CN101529152B

CN101529152B - Backlight unit

Info

Publication number: CN101529152B
Application number: CN2007800400642A
Authority: CN
Inventors: 岸根庆延; 永野英男; 胜本隆一; 佐野芳彦; 涌井博充
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2006-10-27
Filing date: 2007-10-19
Publication date: 2011-04-13
Anticipated expiration: 2027-10-19
Also published as: JP2008112590A; JP5038682B2; CN101529152A

Abstract

The present invention discloses a backlight unit comprising a plurality of linear light sources, and an optical functional sheet, wherein a prism structure having a plurality of prisms is formed on at least one surface of the optical functional sheet, and the values of (Hn-1 + Hn)/(An- An-1) are approximately equivalent, wherein, in a brightness distribution graph that expresses a brightness distribution in the optical functional sheet, A1 is a peak site and H1 is a peak height of a first virtual image, A2 is a peak site and H2 is a peak height of a second virtual image adjacent to the first virtual image, An is a peak site and Hn is a peak height of (n)th virtual image adjacent to (n-1)th virtual image, and these virtual images are derived from the plurality of linear light sources.

Description

Back light unit

Technical field

The present invention relates to be used for the back light unit of the display, display unit, illuminator etc. of liquid crystal indicator, described back light unit is equipped with line source and optical function sheet, and described optical function sheet can show light-focusing function and light diffusion function.

Background technology

In recent years, use lens coating and/or diffusion disk with will be from the light optically focused of light source such as optical waveguide to forward direction, perhaps diffusion be used for the light such as the purposes of liquid crystal display cells and OLED display.

Be used for as shown in Figure 40 TV under type backlight, for example, enter the condensing film 91 of optical function sheet as the output light of optical waveguide from light source 92, the part of incident light in optical function sheet 91 refraction and transmission to change the angle of departure, and towards forward direction emission, and surplus light is reflected and returns towards light source 92.Reverberation from optical function sheet 91 reflects on the surface of light source 92, diffusing panel 93 and diffusion disk 94, enters condensing film then.

Above-mentioned structure can improve directional characteristic, makes by optical function sheet 91 brightness from the light of light source to be uprised on forward direction, and reason is wide and low inherently in the brightness of front side from the Luminance Distribution of the output light of light source.

In order to improve the light diffusion function of the optical function sheet 91 that in back light unit, uses, can be according to the surface structure of the spacing cyclomorphosis prism structure of line source.When improving the light diffusion function of optical function sheet 91, light-focusing function trends towards descending, therefore, and in some cases, can arrange the apex portion or the drift angle of prism structure to a certain extent, perhaps can partly change prism structure to seek light diffusion function and light-focusing function simultaneously.

Particularly, by the meticulous prism structure of change optical function sheet or aligning (alignment) spacing of line source, can reduce the inhomogeneities (referring to for example patent documentation 1) of line source; Yet occurred such as following problem: front face brightness reduces, and mould is essential for each alignment pitch of required line source, and location matches becomes necessary.

By alignment pitch cyclomorphosis prism structure, also can prevent the inhomogeneities (referring to for example patent documentation 2) of line source according to line source; Yet occurred such as following problem: front face brightness reduces, and location matches becomes necessary.

Can also prevent the inhomogeneities of line source in the following manner: the drift angle of prism structure is set at 40 ° to 80 °, thereby make the light diffusion of launching under the line source, and by the summit of prism structure is provided with curved surface, promptly, make the summit bending, the caused secondary lobe of littler drift angle (sidelobe) that can solve by prism structure increases (referring to patent documentation 3, for example); Yet such problem occurred: even location matches is optional, light-focusing function also reduces.Above-mentioned " secondary lobe " is meant this a kind of phenomenon: even purpose is at the front side of display optically focused, according to the shape of concentration piece, except 0 ° front side, one or more peaks also occur on one or more about 70 ° incline directions.

Can provide the drift angle of the prism structure of high diffusive power to calculate in the following manner: molding has the prism of v-depression on the surface of light diffusing board, and limits the spacing and the distance between light diffusing board and line source (referring to for example patent documentation 4) of line source.Yet, light-focusing function occurs and reduce such problem.In addition, below 60 °, promptly increase the drift angle of the cross section of prism structure with respect to the line source rotation, can improve diffusive power by making the prism that forms v-depression on it; Yet following such problem occurred: from being different from the side of front side, the inhomogeneities of line source becomes more obvious, and reason is that Luminance Distribution changes according to angle, and product yield descends along with the increase of rotation.

Patent documentation 1: Japanese Patent Application Publication (JP-A) 06-308485

Patent documentation 2-JP-A 2002-352611

Patent documentation 3:JP-A 2006-140124

Patent documentation 4:JP-A 2006-195276

Summary of the invention

The present invention is intended to solve the problems referred to above in this area, and reaches following purpose.That is, an object of the present invention is to provide a kind of back light unit, described back light unit can improve the light diffusion function, and reduces the inhomogeneities of line source, and does not reduce light-focusing function, produces secondary lobe or reduce productivity ratio etc.

The problems referred to above can solve by following the present invention:

＜1〉a kind of back light unit, it comprises a plurality of line sources and comprises the optical function sheet, wherein forms prism structure with a plurality of prisms and (H at least one surface of optical function sheet _N-1+ H _n)/(A _n-A _N-1) value about equally,

Wherein, in the intensity map of the Luminance Distribution in the display optical functional sheet, B _MaximumFor in the optical function sheet at the high-high brightness and the B of the core of back light unit _MinimumBe minimum brightness; A ₁Be the peak position of first virtual image, and H ₁Be peak height, A ₂Be the peak position and the H of second virtual image of contiguous first virtual image ₂Be peak height,----, A _N-1Be the peak position and the H of (n-1) virtual image of contiguous (n-2) virtual image _N-1Be peak height, and A _nBe the peak position and the H of (n) virtual image of contiguous (n-1) virtual image _nBe peak height, and these virtual images obtain by a plurality of line sources, and

The described virtual image and its peak height H _nSatisfy H _n〉=0.3 * (B _Maximum-B _Minimum) the peak correspondence of condition; And intensity map shows that back light unit wherein not only be not equipped with diffusion disk but also be not equipped with Luminance Distribution in the optical function sheet of diffusing panel.

According to＜1 〉, can improve the light diffusion function, and not reduce light-focusing function, and can reduce the inhomogeneities of linear sources light.

＜2〉according to＜1〉described back light unit, wherein the ratio of the distance between the peak position of the summation of the peak height of the virtual image of the peak height of a virtual image among a plurality of virtual images that obtained by a plurality of line sources and a contiguous described virtual image and described adjacent image about equally.

＜3〉a kind of back light unit, it comprises a plurality of line sources and comprises the optical function sheet, wherein at least one surface of optical function sheet, form prism structure with a plurality of prisms, the virtual image of the optical function sheet that obtains by a plurality of line sources aspect their brightness about equally, and the distance between the contiguous virtual image of optical function sheet is about equally.

According to＜3 〉, the virtual image of the optical function sheet that obtains by a plurality of line sources aspect their brightness about equally, and the distance between the contiguous virtual image of optical function sheet about equally, therefore, can improve the light diffusion function, and do not reduce light-focusing function, and can reduce the inhomogeneities of line source light.

＜4〉according to＜3〉described back light unit, wherein in the intensity map of the Luminance Distribution in the display optical functional sheet, at R ₁To R _nEach zone in exist quantity about equally and luminance peaks highly about equally with about equally interval,

Wherein, R ₁Be the zone of secondary light source among a plurality of line sources from first light source to contiguous first light source, R ₂Be the zone of the 3rd light source from secondary light source to contiguous secondary light source,---, R _N-1Be the zone of (n) light source from (n-1) light source to contiguous (n-1) light source, and R _nIt is the zone of (n+1) light source from (n) light source to contiguous (n) light source.

＜5〉according to＜1〉to＜4 in each described back light unit, wherein said back light unit also comprises diffusion disk, in the region R of described optical function sheet _nThe standard deviation value of inner brightness is divided by the region R of optical function sheet _nInner average brightness is less than 0.0100,

＜6〉according to＜1〉to＜5 in each described back light unit, wherein the aligning of prism (aligning) direction favours the orientation direction of line source.

＜7 〉, wherein be chosen in the feasible (H of distance " d " between line source and the optical function sheet according to＜1〉described back light unit _N-1+ H _n)/(A _n-A _N-1) the value constant.

According to＜7 〉, be chosen in the feasible (H of distance " d " between line source and the optical function sheet _N-1+ H _n)/(A _n-A _N-1) the value constant, therefore can improve the light diffusion function, and not reduce light-focusing function, and can reduce the inhomogeneities of line source light.

＜8〉according to＜7〉described back light unit, wherein among a plurality of virtual images that obtained by a plurality of line sources, the ratio of the distance between the summation of the peak height of the virtual image of the peak height of a virtual image and a contiguous described virtual image and the peak position of described adjacent image about equally.

＜9 〉, wherein be chosen in the distance between line source and the optical function sheet according to＜3〉described back light unit " d " make in the optical function sheet between the contiguous virtual image apart from constant.

According to＜9 〉, the virtual image of the optical function sheet that obtains by a plurality of line sources aspect their brightness about equally, and be chosen in the distance between line source and the optical function sheet " d " make in the optical function sheet between the contiguous virtual image apart from constant, therefore can improve the light diffusion function, and do not reduce light-focusing function, and can reduce the inhomogeneities of line source light.

＜10〉according to＜7〉to＜9 in each described back light unit, the wherein region R of optical function sheet _nThe standard deviation value of inner brightness is divided by the region R of optical function sheet _nInner average brightness is not more than 0.540,

＜11〉according to＜7〉to＜10 in each described back light unit, wherein based on the refractive index " n " of optical function sheet, the prism surface of emission with respect to oblique angle θ from the light of line source emission, and the spacing of line source " p ", by the distance " d " of following equation (1) calculating between line source and optical function sheet

D=(f (p)-27.9n-0.473 θ+65.7)/0.557 ± 5mm equation (1)

Wherein f (p) is a nodal line and near the distance between the virtual image of nodal line, and is the function of spacing " p "; Wherein nodal line be comprise among a plurality of line sources line source and perpendicular to the plane of optical function sheet with comprise a line between the plane of optical function sheet; The described virtual image is the virtual image the virtual image on nodal line among the virtual image of the optical function sheet that is obtained by line source.

＜12〉according to＜7〉to＜11 in each described back light unit, each of wherein said prism is half quadrangle pyramid, and have two reciprocal first surface of emissions, and two reciprocal second surface of emissions, one area in the area summation of two first surface of emissions and two second surface of emissions about equally, and when the aligning direction of prism was parallel to the orientation direction of line source, f (P) was about p/3 or about 2p/3.

＜13〉according to＜7〉to＜11 in each described back light unit, an optical function sheet with prism of band v-depression wherein is set, and when the aligning direction of prism was parallel to the orientation direction of line source, f (P) was about p/4 or about 3p/4.

＜14〉according to＜7〉to＜11 in each described back light unit, each of wherein said prism is the square pyramid, and when the aligning direction of prism during from X ° of the orientation direction inclination of line source, f (p)=p/ (8 * sin X °) or=p/ (5 * sin X °).

＜15〉according to＜7〉to＜11 in each described back light unit, wherein quadrature is provided with two optical function sheets with prism of band v-depression, and when the aligning direction of the prism of an optical function sheet during from X ° of the orientation direction inclination of line source, f (p) is about p/ (8 * sin X °+8 * cos X °) or about p/ (6.5 * sin X °+6.5 * cos X °).

The present invention can solve the problems referred to above in this area, that is, the present invention can provide a kind of back light unit, and described back light unit can improve the light diffusion function, and the inhomogeneities of reduction line source, and do not reduce light-focusing function, produce secondary lobe or reduce productivity ratio etc.And, when in liquid crystal display systems, using this back light unit, can prevent the Moire fringe of liquid crystal pixel.

The accompanying drawing summary

Fig. 1 is the perspective view of structure that shows the optical function sheet of back light unit of the present invention.

Fig. 2 is the block diagram of structure that shows the manufacturing system of the method be used for the optical function sheet shown in the shop drawings 1.

Fig. 3 A be the display line light source and wherein the shape of the prism of the optical function sheet shown in Fig. 1 be the plane of position relation of the optical function sheet of recessed or protruding square pyramid.

Fig. 3 B illustrates when the brightness of the virtual image that is obtained by line source in the optical function sheet is non-constant, the figure that the distance between the contiguous virtual image changes according to virtual image brightness.

Fig. 3 C is the figure of explanation peak height.

Fig. 3 D illustrates that wherein the quantity of a plurality of line sources is the figure of the back light unit core of " n " (even number).

Fig. 3 E illustrates that the quantity of a plurality of line sources wherein is the figure of 8 back light unit core.

Fig. 3 F illustrates that wherein the quantity of a plurality of line sources is the figure of the back light unit core of " n " (odd number).

Fig. 3 G illustrates that the quantity of a plurality of line sources wherein is the figure of 7 back light unit core.

Fig. 4 A be the display line light source and wherein the shape of the prism of the optical function sheet shown in Fig. 1 be that aspect ratio is the plane of position relation of the optical function sheet of 1.5 recessed or protruding half quadrangle pyramid.

Fig. 4 B shows the terminal of the virtual image that obtained by line source and the terminal overlapped figure of the virtual image that obtained by another line source, and wherein the aligning direction of the prism of half quadrangle pyramid does not favour the orientation direction of line source.

Fig. 4 C shows the virtual image that is obtained by line source and the overlapping figure of virtual image appropriateness that is obtained by another line source, and wherein the aligning direction of the prism of half quadrangle pyramid favours the orientation direction of line source.

Fig. 5 be the display line light source and wherein the shape of the prism of the optical function sheet shown in Fig. 1 be recessed or the plane of the position of the optical function sheet of protruding truncated pyramid relation.

Fig. 6 be the display line light source and wherein the shape of the prism of the optical function sheet shown in Fig. 1 be the figure of position relation of the optical function sheet of recessed or protruding half pyramid.

Fig. 7 be the display line light source and wherein the shape of the prism of the optical function sheet shown in Fig. 1 be the figure of position relation of the optical function sheet of recessed or protruding half quadrangle pyramid.

Fig. 8 is the figure of the position relation of the optical function sheet shown in display line light source and Fig. 1.

Fig. 9 is the plane of the optical function sheet shown in Fig. 1, and wherein the aspect ratio that is shaped as of prism is 1.5 recessed half quadrangle pyramid.

Figure 10 is explanation produces the position of the virtual image in optical function sheet shown in Figure 9 when f (p) is p/3 figure.

Figure 11 is explanation produces the position of the virtual image in optical function sheet shown in Figure 9 when f (p) is 2p/3 figure.

Figure 12 is the plane of the optical function sheet shown in Fig. 1, and wherein the shape of prism is recessed square pyramid.

Figure 13 is the plane of the optical function sheet shown in Fig. 1, and wherein the shape of prism is recessed square pyramid, and the aligning direction of prism tilts 18.4 ° from the aligning direction of line source.

Figure 14 is the perspective view of the optical function sheet shown in Fig. 1, and wherein the shape of prism forms and has v-depression.

Figure 15 is the figure that shows according to the structure of back light unit of the present invention.

Figure 16 is the photograph image of the optical function sheet of embodiment 3-A.

Figure 17 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 16.

Figure 18 is the photograph image of the optical function sheet of embodiment 6-A.

Figure 19 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 18.

Figure 20 is the photograph image of the optical function sheet of embodiment 8-A.

Figure 21 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 20.

Figure 22 is the photograph image of the optical function sheet of embodiment 11-A.

Figure 23 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 22.

Figure 24 is the photograph image of the optical function sheet of comparative example 5-A.

Figure 25 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 24.

Figure 26 is the photograph image of the optical function sheet of embodiment 16-A.

Figure 27 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 26.

Figure 28 is the photograph image of the optical function sheet of comparative example 8-A.

Figure 29 is the photograph image at the optical function sheet of taking except that diffusing panel is not set, under the condition identical with Figure 28.

Figure 30 shows the Luminance Distribution in the optical function sheet of embodiment 2-A to 4-A and 6-A.

Figure 31 shows the Luminance Distribution in the optical function sheet of embodiment 7-A to 9-A and comparative example 2-A.

Figure 32 shows the Luminance Distribution in the optical function sheet of embodiment 10-A to 12-A and comparative example 5-A.

Figure 33 shows the Luminance Distribution in the optical function sheet of embodiment 16-A and comparative example 8-A.

Figure in Figure 34 each zone that to be explanation luminance peaks P be present in R1 to R3 with about equally quantity and interval about equally.

Figure 35 is the figure of explanation Moire fringe.

Figure 36 is the figure of explanation Moire fringe.

Figure 37 is the result's of the analog computation that shows that inhomogeneities is estimated figure.

Figure 38 is the figure that shows the back light unit with reflecting plate.

Figure 39 is the figure that shows the back light unit with reflecting plate and reflector plate.

Figure 40 exemplarily show conventional under type schematic cross-section backlight.

Implement best mode of the present invention

Back light unit

Back light unit of the present invention comprises line source, optical function sheet and other member.

Line source

Optical light source can be cold-cathode tube, thermionic-cathode tube, LED arranged in a straight line or and the combination of LED and optical waveguide.

Cold-cathode tube or thermionic-cathode tube be straight line not necessarily, and can allow to have shape such as following: two parallel pipes connect to form the shape of U-shaped by semicircle, and three parallel pipes connect to form the shape of W shape by three semicircles by shape or four parallel pipes that two semicircles connect to form N shape.

For the viewpoint of brightness uniformly, line source is preferably cold-cathode tube, and for the viewpoint of luminous efficiency, line source is preferably the combination of linearly aligned LED and optical waveguide.The optical function sheet

Fig. 1 is the perspective view that shows the section construction of invention optical function sheet.As shown in fig. 1, invention optical function sheet 1 comprises the substrate 3 that forms aftermentioned prism 4 on it at least, and the optional carrier 2 of supporting substrate 3.Carrier 2 and substrate 3 can be formed by resin.

Substrate 3 has: entering surface 3b (below be sometimes referred to as " plane of reference 3b ") enters wherein via carrier 2 from the light of light source such as backlight emission; And form face 3a at the prism of the opposition side of entering surface 3b, almost completely form a plurality of prisms 4 on it so that light is assembled in a predetermined direction.

The structure of optical function sheet 1 is by prismatic lens and biconvex lens and diffraction grating example.

As required, invention optical function sheet 1 can comprise that other layer is as optical diffusion layer, bottom and intermediate layer.

Carrier

The shape of carrier 2 can be selected according to using suitably, for example, can be rectangle, square or circle.

The structure of carrier 2 can be selected according to using suitably, for example, can be individual layer or multilayer.

The size of carrier 2 can be selected according to using suitably.

The material of carrier 2 (sheet material) can suitably be selected, so long as transparent and have suitable intensity and get final product, for example, can be resin molding, paper (resin-coated paper, synthetic paper etc.), metal forming (aluminium tablet) etc.Particularly, the material of resin molding can be conventional resin molding such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyolefin, acrylic compounds (acryl), polystyrene, Merlon, polyamide, PET (PETG), biaxial stretch-formed PETG, polyamidoimide, polyimides, aromatic polyamides, acylated cellulose, cellulose triacetate, cellulose-acetate propionate and cellulose diacetate.Among these, special preferred polyester, acylated cellulose, acrylic compounds, Merlon and polyolefin.

The width of carrier 2 is typically 0.1 to 3 meter, and the length of carrier 2 is typically 1,000 to 100,000 meter, and the thickness of carrier 2 is typically 1 to 300 μ m, and other size can allow.

The thickness of carrier 2 can be by using for example film thickness instrumentation amount, wherein by clamp the thickness that carrier 2 is measured carrier 2 with this film thickness meter, perhaps by using noncontact film thickness instrumentation amount, wherein by using the thickness of optical interferometry carrier 2.

Carrier 2 can be carried out sided corona treatment, plasma treatment, adhesion promotion processing, heat treatment or dust removal process in advance.At the cutoff (cutoff value) of 0.25mm, the surface roughness Ra of carrier 2 is preferably 3 to 10nm.

Carrier 2 can be to apply in advance on it and those of dry solidification priming coat such as adhesive phase, perhaps forms those of other functional layer at its dorsal part.The structure of carrier 2 also can be individual layer or two-layer above structure.

The mist degree of carrier is not more than 50%, preferably is not more than 40%, more preferably no more than 30%, and more preferably no more than 20%.Be higher than 50% mist degree and may significantly reduce light gathering efficiency.

Mist degree is measuring of the fuzzy level of expression, and for example is, estimates on the basis of the value of measuring according to JIS 7105 by measurement mechanism such as haze meter (model HZ-1 is made by Suga Test Instruments Co.).

Be used to prepare the equipment and the method for optical function sheet

The equipment and the method that are used to prepare the optical function sheet can suitably be selected, as long as concaveconvex shape that can be fine for example, preferably uses the method for the production equipment 20 shown in Fig. 2.

Production equipment 20 is made of following: the knurling rolls 23 of feeding sheet materials unit 21, coater unit 22, drying unit 29, concavo-convex roller, nip rolls 24, resin solidification unit 25, stripper roll 26, diaphragm feed unit 27 and sheet material winder unit 28.

Feeding sheet materials unit 21 works the sheet material effect of supplying with, and is made of the discharge rolls of coiling sheet material on it etc.

Coater unit 22 is devices of coating radiation-hardenable resins on the surface of sheet material, and is made of following: storage tank 22A, feedway (pump) 22B, dispense tip 22C, coiling and the backing roll 22D of support sheet and the pipeline that radiation-hardenable resins is supplied to dispense tip 22C from storage tank 22A when coated sheet of supplying with radiation-hardenable resins.Dispense tip among Fig. 4 is the dispense tip of extrusion type die coater.

Drying unit 29 can suitably be selected from conventional drying unit, and as long as the tunnel type drying device shown in Fig. 2 for example is can the drying coated equably coating fluid on sheet material.Specific embodiment is to use those of radiation heating system, hot air circulating system, far infrared system or vacuum system of heater.

Necessary is, and knurling rolls 23 have has precision, the surface structure of mechanical strength and circularity, and this surface structure can be transferred to relief pattern on the sheet surface.Knurling rolls 23 are preferably for example metallic roll.

On the external peripheral surface of knurling rolls 23, form the relief pattern of meticulous rule.Necessary is the opposite structure of lip-deep meticulous regular relief pattern that meticulous regular relief pattern has the embossed sheet of the goods that prepare with conduct.

Embossed sheet as the goods that prepare can be that lens such as two-dimensional arrangements become the lens of micro concavo-convex pattern such as the embossed sheet of biconvex lens or prism lens; Lens such as three-dimensional arrangement become the embossed sheet of fly's eye (fry eye) lens of micro concavo-convex pattern; Perhaps wherein on the X-Y direction, lay the embossed sheet of the flat-plate lens of fine petrosae such as circular cone or pyramid; Make the meticulous regular relief pattern of the external peripheral surface on knurling rolls 23 corresponding with these lens.

Can be by utilizing the surface of diamond bit (single-point) cutting and processing knurling rolls 23, perhaps on knurling rolls 23 surfaces, directly form recess and protuberance, carry out on the external peripheral surface of knurling rolls 23, forming the method for meticulous regular relief pattern by photoetching, beamwriter lithography (electron beam lithography), Laser Processing etc.Can also make knurling rolls 23 with following method: mould etc. by photoetching, beamwriter lithography, Laser Processing, optical mode and on the metal sheet surface, form relief pattern, and metallic plate is fixed on around the roller.In addition, can also make knurling rolls 23 with following method: mould etc. by photoetching, beamwriter lithography, Laser Processing, optical mode and on surface, form relief pattern than the easier material processed of metal, then by opposite pattern molds of formation such as electrical formings, with the preparation metal sheet, and metallic plate is fixed on around the roller.This method has following feature: when forming opposite pattern mold by electrical forming etc., a plurality of identical plates can be formed by original mould (motherboard).

Preferably the surface of knurling rolls 23 being carried out the demoulding handles.On the surface of knurling rolls 23, carry out the demoulding and handle the structure that can suitably keep meticulous relief pattern.According to purpose, the demoulding is handled and can suitably be selected from various conventional demouldings processing.For example, demoulding processing can be the coating of fluororesin.Preferred knurling rolls 23 dispose driver element.

Shown in the arrow among Fig. 2, knurling rolls 23 rotate in the counterclockwise direction.

Nip rolls 24 is a pair of with knurling rolls 23 formation, by roll-in sheet material is handled and molding, therefore, must have certain mechanical strength, circularity etc.Under the too small situation of the longitudinal modulus (Young's modulus) on the surface of nip rolls 24, may be not enough by the molding processing of roller, and under excessive situation, owing to comprising foreign matter such as dust tetchiness, trend towards producing defective; Thus, longitudinal modulus is preferably in suitable scope.Preferred nip rolls 24 disposes driver element.Shown in arrow among Fig. 2, knurling rolls 24 rotate in the clockwise direction.

Preferred knurling rolls 23 or nip rolls 24 dispose presser unit to apply certain inhibition strength between knurling rolls 23 and nip rolls 24.Also preferred knurling rolls 23 or nip rolls 24 dispose fine regulon suitably to control spacing or gap and the pressure between knurling rolls 23 and the nip rolls 24.

Resin solidification unit 25 is in the radiation unit towards the position of the knurling rolls 23 in nip rolls 24 downstreams.Resin solidification unit 25 utilizes the radiation sheet material of transmission with curing resin layer.Preferably can regulate radiation, and the intensity of irradiation can change according to the transfer rate of sheet material according to the curing performance of resin.Resin solidification unit 25 is by the width columnar lamp example about equally of length and sheet material.A plurality of columnar lamps that can be arranged in parallel perhaps can also be provided with reflecting plate at the dorsal part of columnar lamp.

Stripper roll 26 is a pair of with releasing sheet from knurling rolls 23 with knurling rolls 23 formation, therefore must have certain mechanical strength and circularity.

Particularly, peeling off the position, by piercing through sheet material sheet material is being peeled off to be wound on the stripper roll 26 from knurling rolls 23, it is wound up on the circumferential surface of knurling rolls 23 by making knurling rolls 23 and stripper roll 26 rotations.In order to ensure this effect, stripper roll 26 preferred disposition have driver element.Stripper roll 26 is rotated in the clockwise direction.

Stripper roll 26 can also dispose the cooling unit of cooling sheet material when separating, to guarantee to peel off when the temperature by solidifying rising resin etc.

Can be cured processing in the following manner: the position (3 o ' clock position) from position (9 o ' clock position) that knurling rolls 23 are pushed to separator sheet is provided with the many support roller (not shown)s of facing, and pushes sheet material by many support roller and knurling rolls 23 when solidifying.

The sheet material winder unit 28 of the sheet material that storage is peeled off is made of take up roll etc., to roll sheet material.Sheet material winder unit 28 will be supplied on the surface of sheet material by the diaphragm of contiguous diaphragm feed unit 27 supplies, then two films is superposeed to be stored on the sheet material winder unit 28.

Production equipment 20 can also dispose deflector roll between coater unit 22 and the knurling rolls 23 and/or between stripper roll 26 and sheet material winder unit 28, to make up pipeline and other optional member such as jockey pulley to eliminate the lax of sheet material W.

The operation of production equipment 20 will be described below.Sheet material is transported out with constant speed from feeding sheet materials unit 21.With feeding sheet materials to the coater unit 22 with coating resin on the surface of sheet material.After coating, by the solvent in the drying unit 29 evaporation coating fluids.Then with feeding sheet materials to the molding unit that forms by knurling rolls 23 and nip rolls 24.The sheet material of molding unit by moving continuously between 9 o ' clock positions of knurling rolls 23 are by knurling rolls 23 that are pressed in rotation and nip rolls 24 plays the roller die effect thus.That is, sheet material is wound on the knurling rolls 23 of rotation, and will be transferred on the resin bed at the lip-deep relief pattern of knurling rolls 23.

By resin solidification unit 25, utilize the radiation resin bed that passes sheet material, then with curing resin layer under the state that sheet material is wound on the knurling rolls 23.Then, at 3 o ' clock positions of knurling rolls 23, by sheet material being wound on the stripper roll 26, releasing sheet from the knurling rolls 23.

Can after releasing sheet, utilize the radiation sheet material once more, solidify (in Fig. 2, not showing) with further promotion.

The sheet material of peeling off is delivered in the sheet material winder unit 28, will be supplied on the surface of sheet material, two films are reeled under the state of two film stacks, to be stored on the sheet material winder unit 28 then from the diaphragm of diaphragm feed unit 27 supplies.

By this way, on sheet surface, form resin bed, and can be stable and uniformly by the embossing that knurling rolls carry out with homogeneous thickness.Therefore, can be with high-quality the concavo-convex sheet material of the meticulous regular relief pattern that has of zero defect ground preparation.

Production equipment 20 is as above-mentioned exemplary illustration according to the embodiment of using roller shape knurling rolls 23, alternatively, can use the relief pattern band with embossed configuration, as the endless belt, reason is that such band can provide and similarly effect and the operation of column roller.

The material of optical function sheet

The material of sheet material that is used for the optical function sheet is by resin molding, paper (resin-coated paper, synthetic paper etc.), metal forming examples such as (aluminium tablets).

The material of resin molding is by following example: polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyolefin, acrylic compounds, polystyrene, Merlon, polyamide, PET (PETG), biaxial stretch-formed PETG, polyamide-imides, polyimides, aromatic polyamides, acylated cellulose, cellulose triacetate, cellulose-acetate propionate and cellulose diacetate.Among these, special preferred polyester, acylated cellulose, acrylic compounds, Merlon and polyolefin.

Sheet material is wide 0.1 to 3 meter usually, and long 1,000 to 100,000 meter, and thick 1 to 300 μ m; And other size can allow.

Sheet material can be carried out sided corona treatment, plasma treatment, adhesion promotion processing, heat treatment or dust removal process in advance.At the cutoff of 0.25mm, the surface roughness Ra of carrier is preferably 3 to 10nm.

Sheet material can be to apply in advance on it and those of dry solidification priming coat such as adhesive phase, perhaps forms those of other functional layer at its dorsal part.The structure of sheet material also can be individual layer or two-layer above structure.Sheet material is preferably transparent or translucent, with transmitted light.

The resin that uses in resin bed is by containing the compound of reactive group as (methyl) acryloyl group, vinyl and epoxy radicals, and can with contain the compound example that produces the compound reaction of active specy such as free radical and cationic reactive group by irradiation radiation such as UV ray.

Particularly, preferably contain unsaturated group as the compound (monomer) of the reactive group of (methyl) acryloyl group and vinyl and the combination that produces the light-radical polymerization initiator of free radical by the effect of light for the viewpoint that promotes to solidify.Among these, preferably contain the compound of (methyl) acryloyl group, as (methyl) acrylate, carbamate (methyl) acrylate, epoxy (methyl) acrylate and polyester (methyl) acrylate.The compound that contains (methyl) acryloyl group can be to contain those of one or more (methyl) acryloyl group.As required, can be separately or use with the form of two or more combinations and to contain the compound (monomer) of unsaturated group as the reactive group of (methyl) acryloyl group and vinyl.

For the compound that contains (methyl) acryloyl group, the monofunctional monomer that contains (methyl) acryloyl group is by the following compounds example: (methyl) isobornyl acrylate; (methyl) acrylic acid norbornene ester; (methyl) acrylic acid three ring esters in the last of the ten Heavenly stems; (methyl) acrylic acid two ring pentyl esters; (methyl) acrylic acid two cyclopentene esters; (methyl) cyclohexyl acrylate; (methyl) benzyl acrylate; (methyl) acrylic acid 4-butyl cyclohexyl; acryloyl morpholine; (methyl) acrylic acid 2-hydroxyl ethyl ester; (methyl) acrylic acid 2-hydroxypropyl acrylate; (methyl) acrylic acid 2-hydroxy butyl ester; (methyl) methyl acrylate; (methyl) ethyl acrylate; (methyl) propyl acrylate; (methyl) isopropyl acrylate; (methyl) butyl acrylate; (methyl) acrylic acid pentyl ester; (methyl) isobutyl acrylate; (methyl) tert-butyl acrylate; (methyl) acrylic acid pentyl ester; (methyl) acrylic acid isopentyl ester; (methyl) Hexyl 2-propenoate; (methyl) acrylic acid heptyl ester; (methyl) 2-ethyl hexyl acrylate; (methyl) Isooctyl acrylate monomer; (methyl) 2-EHA; (methyl) acrylic acid ester in the ninth of the ten Heavenly Stems; (methyl) decyl acrylate; (methyl) isodecyl acrylate; (methyl) acrylic acid undecyl ester; (methyl) dodecylacrylate; (methyl) lauryl acrylate; (methyl) stearyl acrylate ester; the different stearyl ester of (methyl) acrylic acid; (methyl) tetrahydrofurfuryl acrylate; (methyl) acrylic acid butoxy ethyl ester; ethoxydiglycol (methyl) acrylate; polyethyleneglycol (methyl) acrylate; polypropylene glycol list (methyl) acrylate; methoxyl group diethylene glycol (DEG) (methyl) acrylate; (methyl) acrylic acid ethoxy ethyl ester; methoxy poly (ethylene glycol) (methyl) acrylate and methoxyl group polypropylene glycol (methyl) acrylate.

The monofunctional monomer that contains aromatic group is by the following compounds example: (methyl) acrylic acid phenoxy ethyl, (methyl) acrylic acid phenoxy group-2-methyl ethyl ester, (methyl) acrylic acid phenoxy group ethoxy ethyl ester, (methyl) acrylic acid 3-phenoxy group-2-hydroxypropyl acrylate, (methyl) acrylic acid 2-phenyl phenoxy ethyl, (methyl) acrylic acid 4-phenyl phenoxy ethyl, (methyl) acrylic acid 3-(2-phenyl)-2-hydroxy propyl ester, (methyl) acrylate to cumyl phenol and reacting ethylene oxide, (methyl) acrylic acid 2-bromine phenoxy ethyl, (methyl) acrylic acid 4-bromine phenoxy ethyl, (methyl) acrylic acid 2,4-dibromo-phenoxy base ethyl ester, (methyl) acrylic acid 2,6-dibromo-phenoxy base ethyl ester, (methyl)

acrylic acid

2,4,6 tribromophenyls and (methyl)

acrylic acid

2,4,6-tribromophenoxy ethyl ester.

The commercially available example that contains the monofunctional monomer of aromatic group comprises Aronix M113, M110, M101, M102, M5700, TO-1317 (producing) by Toagosei Co., Viscoat#192, #193, #220,3BM (producing) by Osaka Organic Chemical Industry Co., NK Ester AMP-10G, AMP-20G (producing) by Shin-Nakamura Chemical Co., Light Acrylate PO-A, P-200A, Epoxy Ester M-600A, Light Ester PO (Kyoeisha Chemical Co.), New Frontier PHE, CEA, PHE-2, BR-30, BR-31, BR-31M, BR-32 (producing) etc. by Dai-ichi Kogyo Seiyaku Co.

The example that per molecule contains the unsaturated monomer of two (methyl) acryloyl groups be the alkyl diol diacrylate as 1,4-butanediol diacrylate, 1,6-hexanediyl ester and 1,9-nonanediol diacrylate; Ethylene glycol bisthioglycolate (methyl) acrylate, tetraethylene glycol diacrylate, PAG diacrylate such as tripropylene glycol two (methyl) acrylate; And neopentyl glycol two (methyl) acrylate, tricyclodecane methanol diacrylate etc.

The example that contains the unsaturated monomer of bis-phenol skeleton is bisphenol-A (methyl) acrylate with the oxirane addition, tetrabromobisphenol A (methyl) acrylate with the oxirane addition, bisphenol-A (methyl) acrylate with the expoxy propane addition, tetrabromobisphenol A (methyl) acrylate with the expoxy propane addition, by bisphenol A diglycidyl ether and synthetic bisphenol-A epoxy (methyl) acrylate of (methyl) acrylic acid epoxy addition reaction, synthetic tetrabromobisphenol A epoxy (methyl) acrylate of epoxy addition reaction by tetrabromobisphenol A diglycidyl ether and (methyl) acrylate, by Bisphenol F diglycidyl ether and synthetic Bisphenol F epoxy (methyl) acrylate of (methyl) acrylic acid epoxy addition reaction, and synthetic tetrabromobisphenol F epoxy (methyl) acrylate of epoxy addition reaction that passes through tetrabromobisphenol F diglycidyl ether and (methyl) acrylate.

Example with commercially available unsaturated monomer of such structure is Viscoat#700, #540 (producing) by Osaka Organic Chemical Industry Co., Aronix M 208, M-210 (producing) by Toagosei Co., NK Ester BPE-100, BPE-200, BPE 500, A-BPE-4 (producing) by Shin-Nakamura Chemical Co., Light Ester BP-4EA, BP-4PA, EpoxyEster 3002M, 3002A, 3000M, 3000A (Kyoeisha Chemical Co.), KAYARADR-551, R-712 (producing) by Nippon Kayaku Co., BPE-4, BPE-10, BR-42M (producing) by Dai-ichi Kogyo Seiyaku Co., Lipoxy VR-77, VR-60, VR-90, SP-1506, SP-1506, SP-1507, SP-1509, SP-1563 (producing) by Showa Highpolymer Co., Neopol V779, Neopol V779MA (producing) by Japanese U-PiCA Co..

The example of (methyl) acrylate unsaturated monomer that trivalent is above is above (methyl) acrylate of trivalent of polyalcohol, as trimethylolpropane tris (methyl) acrylate, pentaerythrite three (methyl) acrylate, trimethylolpropane tris oxygen ethyl (methyl) acrylate and three (2-acryloxy ethyl) chlorinated isocyanurates.

The commercially available example of (methyl) acrylate unsaturated monomer that trivalent is above is AronixM305, M309, M310, M315, M320, M350, M360, M408 (producing) by Toagosei Co., Viscoat#295, #300, #360, GPT, 3PA, #400 (producing) by Osaka OrganicChemical Industry Co., NK Ester TMPT, A-TMPT, A-TMM-3, A-TMM-3L, A-TMMT (producing) by Shin-Nakamura Chemical Co., Light AcrylateTMP-A, TMP-6EO-3A, PE-3A, PE-4A, DPE-6A (Kyoeisha Chemical Co.), KAYARAD PET-30, GPO 303, TMPTA, TPA 320, DPHA, D-310, DPCA-20, DPCA-60 (producing) etc. by Nippon Kayaku Co..

Consider suitable viscosity, can other and carbamate (methyl) acrylate oligomer blending with the compound that contains (methyl) acryloyl group.The example of carbamate (methyl) acrylate comprises PPG such as polyethylene glycol and polytetramethylene glycol; By the synthetic PEPA of the reaction between binary acid and the dihydroxylic alcohols, described binary acid is butanedioic acid, adipic acid, azelaic acid, decanedioic acid, phthalic acid, tetrabydrophthalic anhydride and tetrabydrophthalic anhydride for example, and dihydroxylic alcohols is as ethylene glycol, propylene, diethylene glycol (DEG), triethylene glycol, tetraethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexylene glycol, neopentyl glycol; The polyalcohol of poly-epsilon-caprolactone modification; Ester modified polyalcohol in the poly-methylpent; Alkyl polyols such as ethylene glycol, propane diols, 1,4-butanediol, 1,6-hexylene glycol and neopentyl glycol; The polyalcohol of bisphenol-A skeleton alkylene oxide-modification is as the bisphenol-A with the oxirane addition, and with the bisphenol-A of expoxy propane addition; And by the polyalcohol of Bisphenol F skeleton alkylene oxide-modification as with the Bisphenol F of oxirane addition, with Bisphenol F or carbamate (methyl) acrylate oligomer of their combined preparation, organic PIC such as toluene di-isocyanate(TDI), IPDI, hexamethylene diisocyanate, methyl diphenylene diisocyanate and the XDI of expoxy propane addition, and (methyl) acrylate of hydroxyl is as (methyl) acrylic acid 2-hydroxy methacrylate and (methyl) acrylic acid 2-hydroxy propyl ester.

The example of commercially available carbamate (methyl) acrylate monomer is Aronix M120, M-150, M-156, M-215, M-220, M-225, M-240, M-245, M-270 (producing) by ToagoseiCo., AIB, TBA, LA, LTA, STA, Viscoat#155, IBXA, Viscoat#158, #190, #150, #320, HEA, HPA, Viscoat#2000, #2100, DMA, Viscoat#195, #230, #260, #215, #335HP, #310HP, #310HG, #312 (producing) by Osaka OrganicChemical Industry Co., Light Acrylate IAA, L-A, S-A, BO-A, EC-A, MTG-A, DMP-A, THF-A, IB-XA, HOA, HOP-A, HOA-MPL, HOA-MPE, Light Acrylate 3EG-A, 4EG-A, 9EG-A, NP-A, 1,6HX-A, DCP-A (KyoeishaChemical Co.), KAYARADTC-110S, HDDA, NPGDA, TPGDA, PEG400DA, MANDA, HX-220, HX-620 (producing) by Nippon Kayaku Co., FA-511A, 512A, 513A (producing) by Hitachi Chemical Co., VP (producing) by BASF Co., ACMO, DMAA, DMAPAA (producing) by Kohjin Co..

Carbamate (methyl) acrylate oligomer can be by (a) hydroxyl (methyl) acrylate, (b) organic multiple isocyanate and (c) reaction of polyalcohol prepare; Preferably, (methyl) acrylate and (b) organic multiple isocyanate of this oligomer by (a) hydroxyl, and the reaction of (c) polyalcohol of back and preparing.

The example of optical free radical polymerization initiator comprises acetophenone; the acetophenone benzyl ketals; the 1-hydroxycyclohexylphenylketone; 2; 2-dimethoxy-2-phenyl acetophenone; xanthene ketone; Fluorenone; benzaldehyde; fluorine; anthraquinone; triphenylamine; carbazole; the 3-methyl acetophenone; the 4-chlorobenzophenone; 4; 4 ' dimethoxy-benzophenone; 4; 4 '-diaminobenzophenone; Michler's keton; the benzoin propyl ether; the benzoin ethylether; benzyl dimethyl ketal; 1-(4-isopropyl phenyl)-2-hydroxy-2-methyl propane-1-ketone; 2-hydroxy-2-methyl-1-phenyl-propane-1-ketone; thioxanthones; diethyl thioxanthone; the 2-isopropyl thioxanthone; the 2-clopenthixal ketone; 2-methyl isophthalic acid-[4-(methyl mercapto) phenyl]-2-morpholino-propane-1-ketone; 2; 4; 6-trimethylbenzoyl diphenyl phosphine oxide; two-(2; 6-dimethoxy benzoyl)-2; 4; 4-tri-methyl-amyl phosphine oxide; and ethyl-2; 4,6-trimethylbenzoyl ethoxyl phenenyl phosphine oxide.

The example of commercially available optical free radical polymerization initiator is Irgacure 184,369,651,500,819,907,784,2959, CGI1700, CGI1750, CGI11850, CG24-61, Darocur1116,1173 (being produced by Ciba Specialty Chemicals Co.), Lucirin LR8728,8893X (being produced by BASF Co.), Ubecryl P36 (being produced by UCB Co.), KIP150 (being produced by Lamberti Co.).Among these, consider liquid solubility and high sensitivity, preferred Lucirin LR8893X.

Based on the whole composition of resin, the content of optical free radical polymerization initiator is preferably 0.01 to 10 quality %, more preferably 0.5 to 7 quality %.Be higher than at this content under the situation of 10 quality %, the curing performance of composition, the machinery of cured product and optical property and handling property may reduce, and are lower than at this content under the situation of 0.01 quality %, and solidification rate may reduce.

The composition that forms resin can also comprise photosensitizer.The example of photosensitizer comprises triethylamine, diethylamine, N methyldiethanol amine, monoethanolamine, 4-dimethylaminobenzoic acid, benzoic acid 4-dimethylamino methyl esters, benzoic acid 4-dimethylamino ethyl ester, benzoic acid 4-dimethylamino isopentyl ester etc.

The example of commercially available photosensitizer is Ubecryl P102,103,104,105 (being produced by UCB Co.).

Except that mentioned component, as required, composition can also comprise various additives, as surface improver, thermal polymerization inhibitor, levelling agent, surfactant, colouring agent, storage stabilizing agent, plasticizer, lubricant, solvent, filler, antiaging agent, wetability improver and the antitack agent of antioxidant, UV absorbent, light stabilizer, silane coupler, coating.

The example of antioxidant comprises Irganox 1010,1035,1076,1222 (being produced by Ciba SpecialtyChemicals Co.) and Antigen P, 3C, FR, GA-80 (by Sumitomo Chemical Co. production).

The example of UV absorbent comprises Tinuvin P, 234,320,326,327,328,329,213 (being produced by Ciba Specialty Chemicals Co.) and Seesorb 102,103,110,501,202,712,704 (by Shipro Kasei Kaisha, Ltd. produces).

The example of light stabilizer comprises Tinuvin 292,144,622LD (being produced by Ciba SpecialtyChemicals Co.), Sanol LS770 (being produced by Daiichi-Sankyo Co.) and Sumisorb TM-061 (being produced by Sumitomo Chemical Co.).

The example of silane coupler comprises γ-An Jibingjisanyiyangjiguiwan, γ-Qiu Jibingjisanjiayangjiguiwan, γ-methacryloxypropyl trimethoxy silane, and commercially available product such as SH6062,6030 (producing) and KBE903 by Dow Corning Toray Co., 603,403 (producing) by Shin EtsuChemical Co..

The example of the surface improver that applies comprises silicone additives such as dimethyl siloxane polyethers and non-ion fluorin surfactant.

The example of above-mentioned commercially available silicone additives comprises DC-57, DC-190 (being produced by DowCorning Co.), SH-28PA, SH-29PA, SH-30PA, SH-190 (being produced by Dow CorningToray Co.), KF351, KF352, KF353, KF354 (being produced by Shin-Etsu Chemical Co.), and L-700, L-7002, L-7500, FK-024-90 (being produced by Nippon Unicar Co.); The example of commercially available non-ion fluorin surfactant comprises FC-430, FC-171 (being produced by 3M Co.) and Megafac F-176, F-177, R-08 (Dainippon Ink ﹠amp; Chemicals, Inc.).

The example of antitack agent comprises Plysurf A208F (being produced by Dai-ichi Kogyo Seiyaku Co.).

The organic solvent that is used to regulate the viscosity of resin liquid can be any organic solvent, as long as can mix when mixing with resin liquid, and does not have inhomogeneous as deposits, is separated and the gonorrhoea degree gets final product.The example of organic solvent comprises acetone, methyl ethyl ketone, methyl iso-butyl ketone (MIBK), ethanol, propyl alcohol, butanols, 2-methyl cellosolve, cyclohexanol, cyclohexane, cyclohexanone and toluene.These can use separately or with two or more combining forms.

Under the situation of adding organic solvent, step dry and/or the evaporation organic solvent is essential.When organic solvent residues in the product with significant quantity, following such problem may occur: bad mechanical property, perhaps in the process of using as product, organic solvent evaporation and diffusion consequently produce foul smell or negative effect people's health.Therefore, has high boiling organic solvent because higher Determination of Residual Organic Solvents but unsuitable.On the other hand, organic solvent with low boiling point causes violent evaporation, therefore, surface state possibility roughening, water may be assembled, and owing to the heat of evaporation when the drying is deposited on the surface of composition, and these vestiges may cause planar defect, the danger that perhaps higher vapor concentration increase is caught fire.

Therefore, preferred 50 ℃ to 150 ℃ of the boiling point of organic solvent, more preferably 70 ℃ to 120 ℃.Particularly, organic solvent preferable methyl ethyl ketone (boiling point: 79.6 ℃), 1-propyl alcohol (boiling point: 97.2 ℃) etc.

The content that adds the organic solvent in the resin liquid to depends on the kind of organic solvent, and the viscosity of the resin liquid before adding organic solvent; Preferably, this content is typically 10 to 40 quality %, and preferred 15 to 30 quality % are with abundant raising coating performance.When this content was lower than 10 quality %, the raising of coating performance may be not enough, makes that the effect that reduces viscosity or increase coating weight is not remarkable.On the other hand, when this content is higher than 40 quality %, may occur such as following problem: crawling is even, and reason is that liquid flows on the sheet material easily owing to low excessively viscosity, and perhaps liquid turns to the dorsal part of sheet material.In addition, organic solvent may residue in product inside with significant amount owing to drying not enough in drying steps, therefore following such problem may appear: the function reduction of product, perhaps in the process of using as product, organic solvent evaporation consequently produces foul smell or negative effect people's health.

As required, the method that resin liquid can be by routine mixing and solvent components in heating prepares.

The viscosity of Zhi Bei resin liquid is generally 10 to 50,000mPas at 25 ℃ as mentioned above.When viscosity is too high, be difficult to the resin fluid composition is supplied on substrate or the knurling rolls equably, therefore in the manufacture process of lens, trend towards producing being mingled with of inhomogeneities, ripple or bubble of coating, and be difficult to obtain the lens thickness of expection and be difficult to produce enough lens performances, this is significant under higher linear velocity.Therefore, the viscosity of the resin liquid of the reduction that suits in these cases, its viscosity preferred 10 is to 100mPas, and more preferably 10 to 50mPas.Lower viscosity can obtain by adding appropriate amount of organic or the temperature of coating fluid being set in the suitable scope.

On the other hand, when viscosity is crossed when low, by in the process of knurling rolls mold pressing, may be difficult to control the lens that lens thickness and manufacturing have constant thickness.Suitable in these cases rising viscosity, viscosity preferred 100 is to 3000mPas.

Under the situation of mixed organic solvents, when the step of supplying with resin liquid to providing between the step by the knurling rolls mold pressing by heating and dry when evaporating the step of organic solvent, can resin liquid be supplied with under lower viscosity equably at supplying step, and can be in the resin liquid mold pressing equably that will behind dry organic solvent, have viscosity higher by the step of knurling rolls mold pressing.

The curing materials that produces by the radiation to resin liquid irradiation has preferred more than 1.55 at 25 ℃, more preferably the refractive index more than 1.56.When refractive index is lower than 1.55, can not fully guarantee the front face brightness of optical function sheet.

Other member

As required, back light unit can be equipped with other member.Other member is by reflecting plate, diffusing panel or diffusion disk (Figure 38,39) example.Back light unit shown in Figure 38 is equipped with optical function sheet 101 and light box (light box) 102, and the bottom surface and the side attachment of described light box 102 inside have reflecting plate.Back light unit shown in Figure 39 is equipped with optical function sheet 103, one or more diffusion disk 104, diffusing panel 105 and light box 106, and the bottom surface and the side attachment of described light box 106 inside have reflecting plate.

But prism can be formed on diffusion function member such as diffusing panel and the diffusion disk; Thereby, but can optical function sheet and diffusion function member is integrated, and can reduce manufacturing cost.But prism can be at the linear light source on the diffusion function member or the opposition side of line source.

Position relation between line source in the first embodiment and the optical function sheet

Under the situation that is shaped as the recessed or protruding square pyramid as shown in Fig. 3 A of the prism 4 of optical function sheet 1, the aligning direction of prism 4 (arrow 33) with respect to the direction (arrow 34) of line source with optimum 18.4 ° of (=tan in theory ^-11/3) angle tilts, make that the brightness of the virtual image that obtained by line source is roughly the same on optical function sheet 1, and the distance of the contiguous virtual image that is obtained by line source on optical function sheet 1 is roughly the same, therefore the brightness of the virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same, and the distance of the contiguous virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same.Therefore, can improve the light diffusion function, and not reduce light-focusing function, and can reduce the inhomogeneities of line source.When the aligning direction (arrow 33) of prism 4 with respect to the direction (arrow 34) of line source when not tilting, reach the twice of the brightness of other two positions in the brightness of the virtual image of the center of optical function sheet 1.

Fig. 3 A has shown that the inclination angle between the direction (arrow 34) of aligning direction of prism 4 (arrow 33) and line source is 18.4 ° a situation; The inclination angle is not limited to this value, is suitably to be provided with according to the configuration of diffusion disk, diffusing panel or reflecting plate or the distance between kind and line source and the optical function sheet 1 etc.

Under the situation that is shaped as recessed or protruding square pyramid of the prism 4 of optical function sheet 1, situation that the aligning direction (arrow 33) of prism 4 tilts with X ° angle with respect to the direction (arrow 34) of line source with equate with the brightness between the situation of the angle inclination of (90-X) °.

When the brightness of the virtual image that is obtained by a plurality of line sources for optical function sheet 1 was non-constant, suitable is suitably changed distance between the contiguous virtual image according to the brightness of the virtual image.Particularly, as shown in Fig. 3 B, suitably change the distance between the contiguous virtual image, feasible (H ₁+ H ₂)/(A ₂-A ₁), (H ₂+ H ₃)/(A ₃-A ₂), (H ₃+ H ₄)/(A ₄-A ₃) and (H ₄+ H ₅)/(A ₅-A ₄) value reach about equally; B wherein _Maximum: in the optical function sheet 1 in the high-high brightness of back light unit core, B _Minimum: minimum brightness, A ₁: the peak position of first virtual image among a plurality of virtual images that in optical function sheet 1, obtain, peak height: H by a plurality of line sources 30 ₁(peak brightness B ₁-minimum brightness B _Minimum), A ₂: the peak position of second virtual image of contiguous first virtual image, peak height: H ₂(peak brightness B ₂-minimum brightness B _Minimum), A ₃: the peak position of the 3rd virtual image of contiguous second virtual image, peak height: H ₃(peak brightness B ₃-minimum brightness B _Minimum), A ₄: the peak position of the 4th virtual image of contiguous the 3rd virtual image, peak height: H ₄(peak brightness B ₄-minimum brightness B _Minimum), A ₅: the peak position of the 5th virtual image of contiguous the 4th virtual image, peak height: H ₅(peak brightness B ₅-minimum brightness B _Minimum).

In this manual, the virtual image is corresponding to peak height H _nSatisfy H _n〉=0.3 * (B _Maximum-B _Minimum) the peak of condition.In the intensity map shown in Fig. 3 B, shown the Luminance Distribution in the optical function sheet, wherein back light unit both be not equipped with diffusion disk and be not equipped with diffusing panel yet.

Shown below based on the value result calculated shown in Fig. 3 B:

(H ₁+H ₂)/(A ₂-A ₁)＝(300+300)/6＝100

(H ₂+H ₃)/(A ₃-A ₂)＝(300+100)/4＝100

(H ₃+H ₄)/(A ₄-A ₃)＝(100+100)/2＝100

(H ₄+H ₅)/(A ₅-A ₄)＝(100+300)/4＝100

(H ₁+ H ₂)/(A ₂-A ₁), (H ₂+ H ₃)/(A ₃-A ₂), (H ₃+ H ₄)/(A ₄-A ₃) and (H ₄+ H ₅)/(A ₅-A ₄) value (=100) preferably as far as possible little.

In this, make the contiguous virtual image, i.e. summation (the H of the peak height of (n-1) virtual image and (n) virtual image _N-1+ H _n) and the peak position of these two the contiguous virtual images between distance (A _n-A _N-1) ratio at the back light unit core about equally, reason is because shade (shading) effect, and is uncertain in the peak position and the brightness of the marginal position of back light unit.

Although as shown in Fig. 3 B, because the local minimum of brightness waveform figure is steady state value (minimum brightness B fully _Minimum), so peak height H _nBe calculated as (peak brightness B _n-minimum brightness B _Minimum), but as shown in Fig. 3 C, when the local minimum of brightness waveform figure was variable, peak height H was calculated as (peak brightness B _n-brightness B _T).In this relational expression, B _TBe in the brightness of straight line R (line of the local minimum Q of the local minimum P of the starting point at connection peak and the terminal point at peak) with the joining T of straight line S (by the vertical line of peak position).

Below core backlight will be described.

Quantity at a plurality of line sources as shown in Fig. 3 D is under the situation of " n " (even number), core backlight is defined as comprising the zone of three line sources of (n/2-1), (n/2) and (n/2+1) line source, wherein the line source at edge, the leftmost side is that the line source of first line source, contiguous first line source is second line source,--line source of----, contiguous (n-2) line source is (n-1) line source, and the line source of contiguous (n-1) line source is (n) line source.For example, when the quantity of a plurality of line sources as shown in Fig. 3 E was 8, the zone that comprises the 3rd, the 4th and the 5th line source was the core backlight of definition.

Quantity at a plurality of line sources as shown in Fig. 3 F is under the situation of " n " (odd number), core backlight is defined as comprising ((n+1)/2-1), ((n+1)/2) and (zone of three line sources of (n+1)/2+1) line source, wherein the line source at edge, the leftmost side is that the line source of first line source, contiguous first line source is second line source,--line source of----, contiguous (n-2) line source is (n-1) line source, and the line source of contiguous (n-1) line source is (n) line source.For example, when the quantity of a plurality of line sources as shown in Fig. 3 G was 7, the zone that comprises the 3rd, the 4th and the 5th line source was a core backlight.

The recessed or protruding half quadrangle pyramid that is shaped as at the prism 4 of optical function sheet 1 as shown in Fig. 4 A, wherein aspect ratio is 1.5 (bottom surfaces: 50 μ m * 75 μ m, highly: 25 μ m) and the top of pyramid be under the situation of straight line, when the aligning direction (arrow 43) of prism 4 with respect to the direction (arrow 44) of line source when not tilting, the brightness of three virtual images that obtain by line source for optical function sheet 1 about equally, reason is that the area ratio of light-emitting

area

4e, 4f, 4g and the 4h of line source in prism 4 is 2: 1: 1: 2.

In some cases, when the aligning direction (arrow 43) of prism 4 tilts (Fig. 4 C) with respect to the direction (arrow 44) of line source, rather than when the aligning direction (arrow 43) of prism 4 does not tilt (Fig. 4 B) with respect to the direction (arrow 44) of line source, because the virtual image that is obtained by another line source of the virtual image that is obtained by line source of optical function sheet 1 and optical function sheet 1 is overlapping, the inhomogeneities reduction of line source.

According to the bottom surface about the shape of the prism 4 of optical function sheet 1, aspect ratio is not limited to 1.5, is 1.0 to 5.0 scope and allow it.

In addition, under the situation that is shaped as recessed or protruding four limit truncated pyramids of the prism 4 of optical function sheet 1 as shown in Figure 5, the aligning direction of prism 4 (arrow 63) with respect to the direction (arrow 64) of line source with optimum 26.6 ° of (=tan in theory ^-11/2) angle tilts, make that the brightness of the virtual image that obtained by line source is roughly the same on optical function sheet 1, and the distance of the contiguous virtual image that is obtained by line source on optical function sheet 1 is roughly the same, therefore the brightness of the virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same, and the distance of the contiguous virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same.Therefore, can improve the light diffusion function, and not reduce light-focusing function, and can reduce the inhomogeneities of line source.

Fig. 5 has shown that the inclination angle between the direction (arrow 64) of aligning direction of prism 4 (arrow 63) and line source is 26.6 ° a situation; The inclination angle is not limited to this value, suitably is provided with according to the configuration of diffusion disk, diffusing panel or reflecting plate or the distance between kind and line source and the optical function sheet etc.

Area for surface of

emission

4i, 4j, 4k, 4l and 4m, the ratio of the area of preferred emission face 4i and the area of surface of emission 4m (area of the area of surface of emission 4i/surface of emission 4m) is set to 0.25 to 4, and more preferably the area of surface of

emission

4i, 4j, 4k, 4l and 4m equates.

The shape of prism is not limited to as shown in Figure 5 that its top is the quadrangle pyramid (truncated pyramid) on plane, and on the contrary, the top of pyramid can sphering, thereby improves the light diffusion function.

In addition, under the situation that is shaped as recessed or protruding half four limit truncated pyramids (between the truncated pyramid at interval) of the prism 4 of optical function sheet 1 as shown in Figure 6, the aligning direction of prism 4 (arrow 73) with respect to the direction (arrow 74) of line source with optimum 26.6 ° of (=tan in theory ^-11/2) angle tilts, make that the brightness of the virtual image that obtained by line source is roughly the same on optical function sheet 1, and the distance of the contiguous virtual image that is obtained by line source on optical function sheet 1 is roughly the same, therefore the brightness of the virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same, and the distance of the contiguous virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same.Therefore, can improve the light diffusion function, and not reduce light-focusing function, and can reduce the inhomogeneities of line source.

Fig. 6 has shown that the inclination angle between the direction (arrow 74) of aligning direction of prism 4 (arrow 73) and line source is 26.6 ° a situation; The inclination angle is not limited to this value, suitably is provided with according to the configuration of diffusion disk, diffusing panel or reflecting plate or the distance between kind and line source and the optical function sheet 1 etc.

The shape of prism is not limited to the quadrangle pyramid that its top as shown in Figure 6 is the plane (half four limit truncated pyramids), and on the contrary, the top of pyramid can sphering, thereby improves the light diffusion function.

In addition, under the situation that is shaped as recessed or protruding half quadrangle pyramid (between the pyramid at interval) of the prism 4 of optical function sheet 1 as shown in Figure 7, the aligning direction of prism 4 (arrow 83) with respect to the direction (arrow 84) of line source with optimum 26.6 ° of (=tan in theory ^-11/2) angle tilts, make that the brightness of the virtual image that obtained by line source is roughly the same on optical function sheet 1, and the distance of the contiguous virtual image that is obtained by line source on optical function sheet 1 is roughly the same, therefore the brightness of the virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same, and the distance of the contiguous virtual image that is obtained by a plurality of line sources on optical function sheet 1 is roughly the same.Therefore, can improve the light diffusion function, and not reduce light-focusing function, and can reduce the inhomogeneities of line source.

Fig. 7 has shown that the inclination angle between the direction (arrow 84) of aligning direction of prism 4 (arrow 83) and line source is 26.6 ° a situation; The inclination angle is not limited to this value, suitably is provided with according to the configuration of diffusion disk, diffusing panel or reflecting plate or the distance between kind and line source and the optical function sheet 1 etc.

Under the situation that the shape of the prism 4 of optical function sheet 1 is formed by recessed or protruding v-depression, can adopt the foregoing invention design.

Preferably settle the optical function sheet to make that two prismatic lenses are overlapping with vertical between the direction of v-depression in theory, and placement surface is to a prismatic lens of line source, makes that the angle between the aligning direction of the direction of v-depression and cold-cathode tube is 26.6 ° of (=tan ^-11/2).

Under situation vertically superposed between the direction of two prismatic lenses at v-depression, between the situation that the angle between the aligning direction of the direction of the v-depression of a prismatic lens (towards line source) and cold-cathode tube is X ° situation and angle for (90-X) °, the result equates.

Also the drift angle of the prism shape that is preferably formed by v-depression is set to 60 ° to 120 °.

When light source was not linearity but point-like, the direction that connects the imaginary line of point source of light was considered to the aligning direction of line source.

In order to boost productivity or diffusive power, the top flattening or the sphering of prism 4 perhaps can be able to be reduced the oblique angle θ (surface of emission is with respect to the angle of plane of reference 3b) of prism 4.For the viewpoint of optically focused performance, preferred 40 ° to 50 ° of oblique angle θ, more preferably 44 ° to 46 °.Even also should boost productivity or during diffusive power, oblique angle θ preferably is not more than 45 ° with suppressed sidelobes when the optically focused performance reduces.

Light diffusion function and light-focusing function can also improve by the mode that the diffusion particle is attached in all or part of optical function sheet 1.

The surface of emission of prism 4 is that odd number is unsuitable, and reason is to be angle except that 90 ° in the angle between the opposite surface of emission (drift angle), so the optically focused performance reduces.

When prism 4 is the prism of positive hexagon pyramid, can anticipate the similar effect that reduces inhomogeneities, reason is to produce six virtual images, although the virtual image does not occur with the interval that equates.

Be difficult to make the prism 4 of the above pyramid in positive seven limits, it is very close to each other that reason is that prism can not be positioned to.

Diffusive power can also improve by the mode that reduces oblique angle θ (for example, being 47 ° at the center, is 43 ° at the edge) along with center to the edge from optical function sheet 1 slightly.Diffusive power can also be passed through along with outside from the center of optical function sheet 1, and the mode of the spacing of widens slightly line source 30 improves.Position relation between line source in second embodiment and the optical function sheet

Fig. 8 is the figure of the position relation between optical function sheet shown in the key diagram 1 and the line source.

In the relation of position between optical function sheet 1 shown in Fig. 8 and line source 30, f (p) is a nodal line 40 and near the distance between the virtual image of nodal line; Wherein nodal line is to comprise the line source (for example line source 30A) among a plurality of line sources and perpendicular to the plane of optical function sheet 1 with comprise a line between the plane of optical function sheet 1, and this nodal line is at the incident line 40 of the line source among a plurality of line sources (for example line source 30A) on optical function sheet 1; And the described virtual image is the virtual image (for example virtual image 32A) of the most close nodal line 40 the virtual image on nodal line 40 among the virtual image of the optical function sheet 1 that is obtained by line source (for example line source 30A).F (p) is actually according to following equation (1), by oblique angle (cross section angle) θ of the surface of emission 31 of the refractive index " n " of optical function sheet 1, prism 4, in the distance " d " between line source 30 and the optical function sheet 1 (distance " d " between the bottom at the prism 4 (precise shape) of the center of line source 30 and optical function sheet 1), and the distance D between optical function sheet 1 and point of observation is determined.

In this, when at d=0 to 30mm, n=1.5 to 1.7, θ=40 ° are to 50 ° and condition below the D=250mm time, and f (p) may have and is not less than ± error of 1mm.

F (p)=0.557d+27.9n+0.473 θ-65.7 equation (1)

In the virtual image 32 that is obtained by line source 30 on the optical function sheet 1 is when when point of observation sees through optical function sheet 1 observation line light source 30, the virtual image that produces in the position different with the physical location of line source 30.

Therefore, diffusive power can obtain the optimal virtual image distribute and improve (when the brightness of the virtual image 32 that is obtained by line source 30 about equally the time, the distance between the contiguous virtual image is roughly the same) with the spacing " p " according to line source 30 by chosen distance " d " on optical function sheet 1.Because oblique angle (cross section angle) θ is the angle of the geometric cross section of prism 4, so the diffusion level can regulate by rotary optical functional sheet 1, and do not influence the optically focused performance.

In addition, when the brightness of the virtual image 32 that is obtained by a plurality of line sources 30 for optical function sheet 1 was non-constant, suitable is suitably changed distance between the contiguous virtual image 32 according to the brightness of the virtual image 32.Particularly, as shown in Fig. 3 B, suitably select the distance " d " between line source 30 and the optical function sheet 1, feasible (H ₁+ H ₂)/(A ₂-A ₁), (H ₂+ H ₃)/(A ₃-A ₂), (H ₃+ H ₄)/(A ₄-A ₃) and (H ₄+ H ₅)/(A ₅-A ₄) value reach about equally; B wherein _Maximum: in the optical function sheet 1 in the high-high brightness of back light unit core, B _Minimum: minimum brightness, A ₁: the peak position of first virtual image among a plurality of virtual images 32 that in optical function sheet 1, obtain, peak height: H by a plurality of line sources 30 ₁(peak brightness B ₁-minimum brightness B _Minimum), A ₂: the peak position of second virtual image of contiguous first virtual image, peak height: H ₂(peak brightness B ₂-minimum brightness B _Minimum), A ₃: the peak position of the 3rd virtual image of contiguous second virtual image, peak height: H ₃(peak brightness B ₃-minimum brightness B _Minimum), A ₄: the peak position of the 4th virtual image of contiguous the 3rd virtual image, peak height: H ₄(peak brightness B ₄-minimum brightness B _Minimum), A ₅: the peak position of the 5th virtual image of contiguous the 4th virtual image, peak height: H ₅(peak brightness B ₅-minimum brightness B _Minimum).

In this manual, the virtual image 32 is corresponding to peak height H _nSatisfy H _n〉=0.3 * (B _Maximum-B _Minimum) the peak of condition.In the intensity map shown in Fig. 3 B, shown the Luminance Distribution in the optical function sheet, wherein back light unit both be not equipped with diffusion disk and be not equipped with diffusing panel yet.

Shown below based on the value result calculated shown in Fig. 3 B:

(H ₁+H ₂)/(A ₂-A ₁)＝(300+300)/6＝100

(H ₂+H ₃)/(A ₃-A ₂)＝(300+100)/4＝100

(H ₃+H ₄)/(A ₄-A ₃)＝(100+100)/2＝100

(H ₄+H ₅)/(A ₅-A ₄)＝(100+300)/4＝100

In this, make the contiguous virtual image, i.e. summation (the H of the peak height of (n-1) virtual image and (n) virtual image _N-1+ H _n) and the peak position of the contiguous virtual image between distance (A _n-A _N-1) ratio at the back light unit core about equally, reason is because shadow effect, and is uncertain in the peak position and the brightness of the marginal position of back light unit.

The following describes core backlight.

Quantity at a plurality of line sources as shown in Fig. 3 D is under the situation of " n " (even number), core backlight is defined as comprising the zone of three line sources of (n/2-1), (n/2) and (n/2+1) line source, wherein the line source at edge, the leftmost side is that the line source of first line source, contiguous first line source is second line source,--line source of----, contiguous (n-2) line source is (n-1) line source, and the line source of contiguous (n-1) line source is (n) line source.For example, when the quantity of a plurality of line sources as shown in Fig. 3 E was 8, the zone that comprises the 3rd, the 4th and the 5th line source was a core backlight.

Except that the overlapping virtual image, the quantity of the virtual image of appearance is identical with the quantity of the surface of emission of prism 4.Therefore, under the situation of individual layer, in order to improve diffusive power, quadrangle pyramid prism 4 than the prism 4 with v-depression more preferably.

For example, as shown in Figure 9, wherein each prism 4 has reciprocal two first surface of emission 4b and 4c and reciprocal two second surface of emission 4a and 4d, first surface of emission area S _4bAnd S _4cSummation (S _4b+ S _4c) and second surface of emission area S _4aOr S _4dIn an area identical, and prism shape is for having under the situation of prism 4 of half quadrangle pyramid that aspect ratio (vertically/laterally) AR is 1.5 protruding or concave bottom surface, preferably make the aligning direction of prism 4 parallel at (inclination angle: 0 °) with the orientation direction of line source, thereby 3 virtual images that each prism 4 produces from a line source (for example line source 30A), and with distance " d " optimization between optical function sheet 1 and the line source 30.Therefore, can further improve diffusive power.Under this condition, " d ", " n " and θ by defining equation (1) make and the irregularity in brightness of line source 30 can be minimized f (p)=p/3 (Figure 10) or f (p)=2 * p/3 (Figure 11).The aspect ratio AR of bottom surface is not restricted to 1.5, and can be in the scope of 1＜AR≤5.In this, when AR is 1.5, can be by making the impartial inhomogeneities that reduces in interval between the virtual image, reason is that each line source produces three virtual images, and simultaneously, the equal intervals between the virtual image must not be optimum, reason is when AR is different from 1.5, and the brightness of the virtual image is not constant.

When prism 4 as shown in Figure 12 is bottom surface aspect ratio AR when being the prism of 1.0 recessed or protruding square pyramid, the aligning direction of prism 4 and line source 30 preferably are set so that the inclination angle is 18.4 ° of (=tan ^-11/3) (Figure 13), thereby produce 4 virtual images by a line source (for example line source 30A), and with distance " d " optimization between optical function sheet 1 and the line source 30.Under this condition, " d ", " n " and θ by defining equation (1) make and the irregularity in brightness of line source 30 can be minimized f (p)=p/ (18.4 ° of 8 * sin).The aspect ratio AR of bottom surface is not restricted to 1.0, and can be in the scope of 1≤AR≤5.In this, when AR is 1.0, can be by making the impartial inhomogeneities that reduces in interval between the virtual image, reason is that each line source produces four virtual images, and simultaneously, the equal intervals between the virtual image must not be optimum, reason is when AR is different from 1.0, and the brightness of the virtual image is not constant.

When using the prismatic lens BEFII (producing) for example have recessed or protruding v-depression (Figure 14) during as optical function sheet 1 by Sumitomo3M Ltd., the aligning direction of preferred prism 4 (forming the direction of v-depression) is that parallel (inclination angle: 0 °) is provided with line source 30, thereby produce two virtual images, and with distance " d " optimization between optical function sheet 1 and the line source 30 by a line source (for example line source 30A).Under this condition, " d ", " n " and θ by defining equation (1) make and the irregularity in brightness of line source 30 can be minimized f (p)=p/4 or f (p)=3 * p/4.

Also preferred use for example two prismatic lens BEFII (being produced by Sumitomo 3M Ltd.) with recessed or protruding v-depression is settled as optical function sheet 1, make that the crestal line of two prismatic lenses is vertical, and the aligning direction and the line source 30 of the prism 4 of the prismatic lens BEFII prismatic lens of line source 30 (for example towards) form 26.6 ° of (=tan ^-11/2) inclination angle, thus four virtual images produced by a line source (for example line source 30A), and with distance " d " optimization between optical function sheet 1 and the line source 30.Therefore, can further improve light gathering and diffusive power, and can improve front face brightness.Under this condition, " d ", " n " and θ by defining equation (1) make f (p)=p/ (8 * (26.6 ° of sin26.6 °+cos) or f (p)=p/ (6.5 * (26.6 ° of 26.6 °+cos of sin), the irregularity in brightness of line source 30 can be minimized.

In order to boost productivity or diffusive power, the top flattening or the sphering of prism 4 perhaps can be able to be reduced the oblique angle θ (surface of emission is with respect to the angle of plane of reference 3b) of prism.For the viewpoint of optically focused performance, preferred 40 ° to 50 ° of oblique angle θ, more preferably 44 ° to 46 °.Even also should boost productivity or during diffusive power, oblique angle θ preferably is not more than 45 ° with suppressed sidelobes when the optically focused performance reduces.

Diffusive power can also improve by the mode that reduces oblique angle θ (for example, being 47 ° at the center, is 43 ° at the edge) along with center to the edge from optical function sheet 1 slightly.Diffusive power can also be passed through along with outside from the center of optical function sheet 1, and the mode of the spacing of widens slightly line source 30 improves.

Embodiment

Below with embodiment with reference to the explanation the present invention, but the present invention should not be limited to described embodiment.

Embodiment 1-A

By forming the sheet material that thickness is 200 μ m by polycarbonate resin (refractive index: 1.59, produce) extrusion molding by Mitsubishi Chemical Co.; Then under the condition of 200 ℃, 2MPa and 10 minutes, by to have bottom width be 50 μ m and highly be the mould heat pressure sheet material of the protruding square pyramid pattern of 25 μ m, thus preparation 17cm ²The optical function sheet with recessed square pyramid pattern transferring (Fig. 3 A).By the optical function sheet that obtains, the diameter of a plurality of line sources of conduct of parallel alignment is the cold-cathode tube of 3mm, reflection is from the reflection of light plate (light box) of cold-cathode tube, and be set at diffusing panel (D 121Z between cold-cathode tube and the optical function sheet, produce by Tsujiden Co.) (Figure 15), prepare back light unit in the following manner: the optical function sheet is set makes the aligning direction of prism (square pyramid) of optical function sheet from the orientation direction of cold-cathode tube 7 ° (83 °) that tilt.Distance " d " between cold-cathode tube and optical function sheet is 17mm, and the distance D between optical function sheet and the aftermentioned colour brightness meter is 350mm, and the alignment pitch of cold-cathode tube " p " is under the condition of 23mm, lights cold-cathode tube; Then, by colour brightness meter (BM-7FAST, produce by TopconCo.), on the direction of vertical cold-cathode tube with the brightness of uniform interval measurement optical function sheet, thereby directly over the acquisition cold-cathode tube and the mean flow rate of 1 spacing between directly over the contiguous cold-cathode tube and the standard deviation of brightness, and estimate irregularity in brightness based on following evaluation criterion.

The value of irregularity in brightness=(standard deviation of brightness)/(average brightness)

The evaluation criterion of irregularity in brightness

A: do not have irregularity in brightness

B: low-level irregularity in brightness

C: the irregularity in brightness of certain level

D: the irregularity in brightness of quite big level

As a result of, average brightness is 10, and 021cd, the standard deviation of brightness are 57cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0057, and irregularity in brightness be evaluated as C (table 1).

In this, commercial, the degree of diffusion of display is to use diffusing panel etc. further to improve, and simultaneously, such diffusing panel does not use in an embodiment, and reason is that brightness is emphasized, and can easily confirm to reduce the effect of irregularity in brightness.

Embodiment 2-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube is the mode of 9 ° (81 °).As a result of, average brightness is 9, and 996cd, the standard deviation of brightness are 43cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0043, and irregularity in brightness be evaluated as B (table 1).

Embodiment 3-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube is the mode of 11 ° (79 °).As a result of, average brightness is 10, and 052cd, the standard deviation of brightness are 26cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0025, and irregularity in brightness be evaluated as A (table 1).

Figure 16 has shown the image of taking from above-mentioned optical function sheet; And Figure 17 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Embodiment 4-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube is the mode of 13 ° (77 °).As a result of, average brightness is 9, and 999cd, the standard deviation of brightness are 36cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0036, and irregularity in brightness be evaluated as B (table 1).

Embodiment 5-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube is the mode of 18 ° (72 °).As a result of, average brightness is 9, and 994cd, the standard deviation of brightness are 91cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0091, and irregularity in brightness be evaluated as C (table 1).

Embodiment 6-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is so that the mode of the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube parallel (inclination angle: 0 ° (90 °)) is provided with the optical function sheet.As a result of, average brightness is 10, and 074cd, the standard deviation of brightness are 85cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0085, and irregularity in brightness be evaluated as C (table 1).

Figure 18 has shown the image of taking from above-mentioned optical function sheet; And Figure 19 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Comparative example 1-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube is the mode of 27 ° (63 °).As a result of, average brightness is 9, and 996cd, the standard deviation of brightness are 285cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0285, and irregularity in brightness be evaluated as D (table 1).

The result of embodiment 1-A to 6-A and comparative example 1-A shows, when the angle between the orientation direction of the aligning direction of the prism (square pyramid) of optical function sheet and cold-cathode tube is 0 ° to 18 ° (90 ° to 72 °), preferred 7 ° to 13 ° (83 ° to 77 °), when more preferably 11 ° (79 °), the value of (standard deviation of brightness)/(average brightness) can be less than 0.0100, the i.e. brightness of the virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally, and the distance between the contiguous virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally.

Embodiment 7-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is that it is 1.5 (bottom surfaces: 50 μ m * 75 μ m that use has aspect ratio, highly: the optical function sheet of recessed half quadrangle pyramid pattern transferring (Fig. 4) 25 μ m) replaces having the optical function sheet of recessed square pyramid pattern transferring (Fig. 3 A), and so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (square pyramid) and cold-cathode tube is 70 ° a mode optical function sheet is set.As a result of, average brightness is 10, and 005cd, the standard deviation of brightness are 48cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0048, and irregularity in brightness be evaluated as B (table 1).

Embodiment 8-A

Prepare back light unit and measure brightness with the method identical with embodiment 7-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (half quadrangle pyramid) and cold-cathode tube is 72 ° a mode.As a result of, average brightness is 9, and 793cd, the standard deviation of brightness are 24cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0024, and irregularity in brightness be evaluated as A (table 1).

Figure 20 has shown the image of taking from above-mentioned optical function sheet; And Figure 21 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Embodiment 9-A

Prepare back light unit and measure brightness with the method identical with embodiment 7-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (half quadrangle pyramid) and cold-cathode tube is 74 ° a mode.As a result of, average brightness is 9, and 973cd, the standard deviation of brightness are 65cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0065, and irregularity in brightness be evaluated as B (table 1).

Comparative example 2-A

Prepare back light unit and measure brightness with the method identical with embodiment 7-A, difference is so that the mode of the orientation direction parallel (inclination angle: 0 °) of the aligning direction of the prism of optical function sheet (half quadrangle pyramid) and cold-cathode tube is provided with the optical function sheet.As a result of, average brightness is 10, and 157cd, the standard deviation of brightness are 149cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0147, and irregularity in brightness be evaluated as D (table 1).

Comparative example 3-A

Prepare back light unit and measure brightness with the method identical with embodiment 7-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (half quadrangle pyramid) and cold-cathode tube is 63 ° a mode.As a result of, average brightness is 9, and 916cd, the standard deviation of brightness are 181cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0182, and irregularity in brightness be evaluated as D (table 1).

Comparative example 4-A

Prepare back light unit and measure brightness with the method identical with embodiment 7-A, difference is is provided with the optical function sheet so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet (half quadrangle pyramid) and cold-cathode tube is 81 ° a mode.As a result of, average brightness is 9, and 844cd, the standard deviation of brightness are 186cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0189, and irregularity in brightness be evaluated as D (table 1).

The result of embodiment 7-A to 9-A and comparative example 2-A to 4-A shows, when the angle between the orientation direction of the aligning direction of the prism of optical function sheet and cold-cathode tube is 70 ° to 74 °, in the time of preferred 72 °, the value of (standard deviation of brightness)/(average brightness) can be less than 0.0100, the i.e. brightness of the virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally, and the distance between the contiguous virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally.

Embodiment 10-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is to use the prismatic lens (RBEF with v-depression, produce by Sumitomo 3M Ltd.) replace having the optical function sheet of recessed square pyramid pattern transferring (Fig. 3 A), and the optical function sheet is set so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 63 ° a mode.As a result of, average brightness is 10, and 491cd, the standard deviation of brightness are 91cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0087, and irregularity in brightness be evaluated as C (table 1).

Embodiment 11-A

Prepare back light unit and measure brightness with the method identical with embodiment 10-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 64 ° a mode optical function sheet to be set.As a result of, average brightness is 10, and 520cd, the standard deviation of brightness are 71cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0068, and irregularity in brightness be evaluated as C (table 1).

Figure 22 has shown the image of taking from above-mentioned optical function sheet; And Figure 23 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Embodiment 12-A

Prepare back light unit and measure brightness with the method identical with embodiment 10-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 65 ° a mode optical function sheet to be set.As a result of, average brightness is 10, and 416cd, the standard deviation of brightness are 94cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0090, and irregularity in brightness be evaluated as C (table 1).

Comparative example 5-A

Prepare back light unit and measure brightness with the method identical with embodiment 10-A, difference is so that the mode of the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube parallel (inclination angle: 0 °) is provided with the optical function sheet.As a result of, average brightness is 11, and 176cd, the standard deviation of brightness are 521cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0466, and irregularity in brightness be evaluated as D (table 1).

Figure 24 has shown the image of taking from above-mentioned optical function sheet; And Figure 25 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Comparative example 6-A

Prepare back light unit and measure brightness with the method identical with embodiment 10-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 59 ° a mode optical function sheet to be set.As a result of, average brightness is 10, and 280cd, the standard deviation of brightness are 201cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0195, and irregularity in brightness be evaluated as D (table 1).

Comparative example 7-A

Prepare back light unit and measure brightness with the method identical with embodiment 10-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 69 ° a mode optical function sheet to be set.As a result of, average brightness is 10, and 384cd, the standard deviation of brightness are 164cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0158, and irregularity in brightness be evaluated as D (table 1).

The result of embodiment 10-A to 12-A and comparative example 5-A to 7-A shows, when the angle between the orientation direction of the aligning direction of the prism of optical function sheet and cold-cathode tube is 63 ° to 65 °, in the time of preferred 64 °, the value of (standard deviation of brightness)/(average brightness) can be less than 0.0100, the i.e. brightness of the virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally, and the distance between the contiguous virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally.

Embodiment 13-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is the prismatic lens (RBEF that uses two to have v-depression, produce by Sumitomo 3M Ltd.) replace having the optical function sheet of recessed square pyramid pattern transferring (Fig. 3 A), two prismatic lenses are overlapping in the vertical mode of the direction of v-depression, and the direction of the v-depression of a prismatic lens (towards line source) is from 30 ° (60 °) of orientation direction inclination of cold-cathode tube.As a result of, average brightness is 11, and 917cd, the standard deviation of brightness are 104cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0088, and irregularity in brightness be evaluated as C (table 1).

Embodiment 14-A

Prepare back light unit and measure brightness with the method identical with embodiment 13-A, difference is that the direction of v-depression of a prismatic lens (towards line source) is from the orientation direction of cold-cathode tube 32 ° (58 °) that tilt.As a result of, average brightness is 12, and 032cd, the standard deviation of brightness are 67cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0055, and irregularity in brightness be evaluated as C (table 1).

Embodiment 15-A

Prepare back light unit and measure brightness with the method identical with embodiment 13-A, difference is that the direction of v-depression of a prismatic lens (towards line source) is from the orientation direction of cold-cathode tube 34 ° (56 °) that tilt.As a result of, average brightness is 11, and 968cd, the standard deviation of brightness are 54cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0046, and irregularity in brightness be evaluated as B (table 1).

Embodiment 16-A

Prepare back light unit and measure brightness with the method identical with embodiment 13-A, difference is that the direction of v-depression of a prismatic lens (towards line source) is from the orientation direction of cold-cathode tube 36 ° (54 °) that tilt.As a result of, average brightness is 11, and 849cd, the standard deviation of brightness are 18cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0015, and irregularity in brightness be evaluated as A (table 1).

Figure 26 has shown the image of taking from above-mentioned optical function sheet; And Figure 27 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Embodiment 17-A

Prepare back light unit and measure brightness with the method identical with embodiment 13-A, difference is that the direction of the v-depression of a prismatic lens (towards line source) tilts 45 ° from the orientation direction of cold-cathode tube.As a result of, average brightness is 11, and 981cd, the standard deviation of brightness are 26cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0022, and irregularity in brightness be evaluated as A (table 1).

Comparative example 8-A

Prepare back light unit and measure brightness with the method identical with embodiment 13-A, difference is the direction parallel with the orientation direction of cold-cathode tube (inclination angle: 0 ° (90 °)) of the v-depression of a prismatic lens (towards line source).As a result of, average brightness is 12, and 047cd, the standard deviation of brightness are 120cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0100, and irregularity in brightness be evaluated as D (table 1).

Figure 28 has shown the image of taking from above-mentioned optical function sheet; And Figure 29 has shown diffusion disk (D121Z, by Tsujiden Co. produce) wherein has not been set so that the clearer image of the virtual image between cold-cathode tube and optical function sheet.

Comparative example 9-A

Prepare back light unit and measure brightness with the method identical with embodiment 13-A, difference is that the direction of v-depression of a prismatic lens (towards line source) is from the orientation direction of cold-cathode tube 27 ° (63 °) that tilt.As a result of, average brightness is 11, and 928cd, the standard deviation of brightness are 141cd, and the value of (standard deviation of brightness)/(average brightness) is 0.0118, and irregularity in brightness be evaluated as D (table 1).

The result of embodiment 13-A to 17-A and comparative example 8-A to 9-A shows, when the angle between the orientation direction of the aligning direction of the prism of optical function sheet and cold-cathode tube is 30 ° to 45 ° (60 ° to 45 °), preferred 36 ° (54 ° the time, the value of (standard deviation of brightness)/(average brightness) can be less than 0.0100, the i.e. brightness of the virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally, and the distance between the contiguous virtual image of the optical function sheet that is obtained by a plurality of line sources can be about equally.

Reference example 1-A

Prepare back light unit and measure brightness with the method identical with embodiment 1-A, difference is to use the prismatic lens (RBEF with v-depression, produce by Sumitomo 3M Ltd.) replace having the optical function sheet of recessed square pyramid pattern transferring (Fig. 3 A), so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 0 ° a mode optical function sheet is set, and diffusion disk (D121Z is produced by Tsujiden Co.) is not set.As a result of, average brightness is 9, and 688cd, the standard deviation of brightness are 4,674cd, the value of (standard deviation of brightness)/(average brightness) is 0.4825, and irregularity in brightness be evaluated as D (table 1).

Reference example 2-A

Prepare back light unit and measure brightness with the method identical with reference example 1-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 18 ° a mode optical function sheet to be set.As a result of, average brightness is 9, and 715cd, the standard deviation of brightness are 4,163cd, the value of (standard deviation of brightness)/(average brightness) is 0.4285, and irregularity in brightness be evaluated as D (table 1).

Reference example 3-A

Prepare back light unit and measure brightness with the method identical with reference example 1-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 36 ° a mode optical function sheet to be set.As a result of, average brightness is 9, and 755cd, the standard deviation of brightness are 3,613cd, the value of (standard deviation of brightness)/(average brightness) is 0.3704, and irregularity in brightness be evaluated as D (table 1).

Reference example 4-A

Prepare back light unit and measure brightness with the method identical with reference example 1-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 54 ° a mode optical function sheet to be set.As a result of, average brightness is 9, and 528cd, the standard deviation of brightness are 2,968cd, the value of (standard deviation of brightness)/(average brightness) is 0.3115, and irregularity in brightness be evaluated as D (table 1).

Reference example 5-A

Prepare back light unit and measure brightness with the method identical with reference example 1-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 72 ° a mode optical function sheet to be set.As a result of, average brightness is 9, and 206cd, the standard deviation of brightness are 3,264cd, the value of (standard deviation of brightness)/(average brightness) is 0.3546, and irregularity in brightness be evaluated as D (table 1).

Reference example 6-A

Prepare back light unit and measure brightness with the method identical with reference example 1-A, difference is so that the angle between the orientation direction of the aligning direction of the v-depression of prismatic lens and cold-cathode tube is 90 ° a mode optical function sheet to be set.As a result of, average brightness is 9, and 253cd, the standard deviation of brightness are 5,380cd, the value of (standard deviation of brightness)/(average brightness) is 0.5814, and irregularity in brightness be evaluated as D (table 1).

The result of reference example 1-A to 6-A shows, when when the angle between the orientation direction of the aligning direction of the prism of optical function sheet and cold-cathode tube is 54 ° to 72 °, the value of (standard deviation of brightness)/(average brightness) is that 0 ° situation is relatively little than angle.That is, show whether no matter diffusion disk be set (D121Z is produced by Tsujiden Co.), the value of (standard deviation of brightness)/(average brightness) all is roughly the same.

In this, when using haze value, it is believed that best angle will be from 45 ° of skews as its center than the higher diffusion disk of the haze value of diffusion disk (D121Z is produced by Tsujiden Co.) or when using a plurality of diffusion disk.For example, best angle will reach 18 ° for 20 °, and best angle will reach 72 ° for 70 °.

Table 1

	Prism shape	Diffusion disk	The inclination angle (°)	AB (cd)	SDB (cd)	SDB/AB	Irregularity in brightness
								Embodiment 1-A	CRFP	Have	7	10,021	57	0.0057	C
Embodiment 2-A	CRFP	Have	9	9,996	43	0.0043	B
								Embodiment 3-A	CRFP	Have	11	10,052	26	0.0025	A
Embodiment 4-A	CRFP	Have		13	9,999	36	0.0036									B
								Embodiment 5-A	CRFP	Have	18	9,994	91	0.0091	C
Embodiment 6-A	CRFP	Have	0	10,074	85	0.0085	C
								Comparative example 1-A	CRFP	Have		27	9,996	285	0.0285	D
Embodiment 7-A	CSP	Have	70	10,005	48	0.0048	B
								Embodiment 8-A	CSP	Have	72	9,793	24	0.0024	A
Embodiment 9-A	CSP	Have	74	9,973	65	0.0065	B
								Comparative example 2-A	CSP	Have	0	10,157	149	0.0147	D
Comparative example 3-A	CSP	Have	63	9,916	181	0.0182	D
								Comparative example 4-A	CSP	Have	81	9,844	186	0.0189	D
Embodiment 10-A	1 V sheet	Have	63	10,491	91	0.0087	C
								Embodiment 11-A	1 V sheet	Have	64	10,520	71	0.0068	C
Embodiment 12-A	1 V sheet	Have	65	10,416	94	0.0090	C

Comparative example 5-A	1 V sheet	Have	0	11,176	521	0.0466	D
								Comparative example 6-A	1 V sheet	Have	59	10,280	201	0.0195	D
Comparative example 7-A	1 V sheet	Have	69	10,384	164	0.0158	D
								Embodiment 13-A	2 V sheets	Have	30	11,917	104	0.0088	C
Embodiment 14-A	2 V sheets	Have	32	12,032	67	0.0055	C
								Embodiment 15-A	2 V sheets	Have	34	11,968	54	0.0046	B
Embodiment 16-A	2 V sheets	Have	36	11,849	18	0.0015	A
								Embodiment 17-A	2 V sheets	Have	45	11,981	26	0.0022	A
Comparative example 8-A	2 V sheets	Have	0	12,047	120	0.0100	D
								Comparative example 9-A	2 V sheets	Have	27	11,928	141	0.0118	D
Reference example 1-A	1 V sheet	Do not have	0	9,688	4,674	0.4825	D
								Reference example 2-A	1 V sheet	Do not have	18	9,715	4,163	0.4285	D
Reference example 3-A	1 V sheet	Do not have	36	9,755	3,613	0.3704	D
								Reference example 4-A	1 V sheet	Do not have	54	9,528	2,968	0.3115	D
Reference example 5-A	1 V sheet	Do not have	72	9,206	3,264	0.3546	D
								Reference example 6-A	1 V sheet	Do not have	90	9,253	5,380	0.5814	D

CRFP: recessed square pyramid (Fig. 3 A)

CSP: recessed half quadrangle pyramid (Fig. 4 A)

1 V sheet: 1 prismatic lens with v-depression

2 V sheets: 2 prismatic lenses with v-depression

AB: average brightness

SDB: the standard deviation of brightness

Figure 30 has shown embodiment 6-A (square pyramid (Fig. 3 A), inclination angle: 0 °), embodiment 2-A (square pyramid (Fig. 3 A), inclination angle: 9 °), embodiment 3-A (square pyramid (Fig. 3 A), inclination angle: 11 °) and the Luminance Distribution in the optical function sheet of embodiment 4-A (square pyramid (Fig. 3 A), inclination angle: 13 °); Figure 31 has shown comparative example 2-A (half quadrangle pyramid (Fig. 4 A), inclination angle: 0 °), embodiment 7-A (half quadrangle pyramid (Fig. 4 A), inclination angle: 70 °), embodiment 8-A (half quadrangle pyramid (Fig. 4 A), inclination angle: 72 °) and the Luminance Distribution in the optical function sheet of embodiment 9-A (half quadrangle pyramid (Fig. 4 A), inclination angle: 74 °); Figure 32 has shown comparative example 5-A (1 sheet material with v-depression, inclination angle: 0 °), embodiment 10-A (1 sheet material with v-depression, inclination angle: 63 °), embodiment 11-A (1 sheet material with v-depression, inclination angle: 64 °) and the Luminance Distribution in the optical function sheet of embodiment 12-A (1 sheet material, inclination angle: 65 °) with v-depression; Figure 33 has shown the Luminance Distribution in the optical function sheet of comparative example 8-A (2 sheet materials with v-depression, inclination angle: 0 °) and embodiment 16-A (2 sheet materials with v-depression, inclination angle: 36 °).

In each intensity map, vertical line is represented brightness (cd/mm ²), horizontal line represents position (from the distance of reference point), and line source exists in the position of 13.5mm, 36.5mm, 59.5mm and 82.5mm.

The result of Figure 30 to 33 shows, when the aligning direction of the prism of optical function sheet when the orientation direction of line source tilts at a certain angle, the Luminance Distribution line is more flat, and irregularity in brightness does not reduce more from the tilt situation at (inclination angle: 0 °) of the orientation direction of line source than the aligning direction of the prism of optical function sheet.

For the intensity map in the optical function sheet, most preferably there is not luminance peaks; Yet, even there is for example luminance peaks P shown in Figure 34, also preferably exist quantity about equally with about equally interval at each intra-zone of R1 to R3 from line source to its contiguous light source, and luminance peaks P highly about equally, and the interval of the distance from the rightmost side luminance peaks P of region R 1 (or R2) to the leftmost side luminance peaks P of region R 2 (or R3) and the luminance peaks P of region R 1 to R3 inside about equally.

Embodiment 1-B

By forming the sheet material that thickness is 200 μ m by polycarbonate resin (refractive index: 1.59, produce) extrusion molding by Mitsubishi Chemical Co.; Then under the condition of 200 ℃, 2MPa and 10 minutes, by aspect ratio is 1.5 (bottom surfaces: 50 μ m * 75 μ m, highly: the mould heat pressure sheet material of raised design 25 μ m), thus preparation has the optical function sheet of recessed square pyramid pattern transferring (Fig. 9) (oblique angle θ: 45 °).By the optical function sheet that obtains, the cold-cathode tube of a plurality of line sources of conduct of parallel alignment, and reflection prepares back light unit in the following manner from the reflection of light plate (light box) of cold-cathode tube: the optical function sheet is set makes that the angle between the orientation direction of aligning direction and cold-cathode tube of prism (square pyramid) of optical function sheet is parallel (0 °).Distance " d " between cold-cathode tube and optical function sheet is 13.5mm, and the distance D between optical function sheet and the point of observation (aftermentioned colour brightness meter) is 350mm, and the alignment pitch of cold-cathode tube " p " is under the condition of 23mm, lights cold-cathode tube; Then, by colour brightness meter (BM-7FAST, produce by Topcon Co.), on the direction of vertical cold-cathode tube with the brightness of uniform interval measurement optical function sheet, thereby the mean flow rate of 1 spacing between directly over the cold-cathode tube that extremely is close to directly over the acquisition cold-cathode tube and the standard deviation of brightness, and based on following evaluation criterion evaluation irregularity in brightness.

The value of irregularity in brightness: (standard deviation of brightness)/(average brightness)

The evaluation criterion of irregularity in brightness

A: do not have irregularity in brightness

B: low-level irregularity in brightness

C: the irregularity in brightness of certain level

D: the irregularity in brightness of quite big level

As a result of, average brightness is 9, and 240cd, the standard deviation of brightness are 3,220cd, the value of (standard deviation of brightness)/(average brightness) is 0.348, and irregularity in brightness be evaluated as B (table 2).

In this, commercial, the degree of diffusion of display is to use diffusing panel, diffusion disk etc. further to improve, simultaneously, such diffusing panel and diffusion disk do not use in an embodiment, and reason is that brightness is emphasized, and can easily confirm to reduce the effect of irregularity in brightness.

Embodiment 2-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 28.5mm.As a result of, average brightness is 9, and 310cd, the standard deviation of brightness are 3,240cd, the value of (standard deviation of brightness)/(average brightness) is 0.348, and irregularity in brightness be evaluated as B (table 2).

Comparative example 1-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 5.0mm.As a result of, average brightness is 9, and 180cd, the standard deviation of brightness are 5,020cd, the value of (standard deviation of brightness)/(average brightness) is 0.547, and irregularity in brightness be evaluated as D (table 2).

Embodiment 3-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 11.0mm.As a result of, average brightness is 9, and 370cd, the standard deviation of brightness are 3,530cd, the value of (standard deviation of brightness)/(average brightness) is 0.377, and irregularity in brightness be evaluated as C (table 2).

Embodiment 4-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 16.0mm.As a result of, average brightness is 9, and 100cd, the standard deviation of brightness are 3,470cd, the value of (standard deviation of brightness)/(average brightness) is 0.381, and irregularity in brightness be evaluated as B (table 2).

Comparative example 2-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 21.0mm.As a result of, average brightness is 9, and 150cd, the standard deviation of brightness are 5,560cd, the value of (standard deviation of brightness)/(average brightness) is 0.608, and irregularity in brightness be evaluated as D (table 2).

Embodiment 5-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 26.0mm.As a result of, average brightness is 9, and 220cd, the standard deviation of brightness are 3,470cd, the value of (standard deviation of brightness)/(average brightness) is 0.376, and irregularity in brightness be evaluated as B (table 2).

Embodiment 6-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 31.0mm.As a result of, average brightness is 9, and 160cd, the standard deviation of brightness are 3,530cd, the value of (standard deviation of brightness)/(average brightness) is 0.385, and irregularity in brightness be evaluated as C (table 2).

Comparative example 3-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 45.0mm.As a result of, average brightness is 9, and 150cd, the standard deviation of brightness are 8,380cd, the value of (standard deviation of brightness)/(average brightness) is 0.916, and irregularity in brightness be evaluated as D (table 2).

When " d " that adopt equation (1) calculating optimum made f (p)=p/3 or f (p)=2 * p/3, under the condition of embodiment 1-B to 6-B and comparative example 1-B to 3-B, " d " was calculated as 13.9mm or 27.6mm; And obtained the desired value (being not more than 0.540) of (standard deviation of brightness)/(average brightness), and in 8.9 to 18.9mm or 22.6 to 32.6mm scope, irregularity in brightness be evaluated as B or C.

Embodiment 7-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is to use prismatic lens BEFII (being produced by the Sumitomo 3M Ltd.) replacement with v-depression (Figure 14) to have the optical function sheet of recessed half quadrangle pyramid pattern transferring (Fig. 9), and the distance " d " between cold-cathode tube and the optical function sheet is changed into 9.8mm.As a result of, average brightness is 10, and 130cd, the standard deviation of brightness are 4,920cd, the value of (standard deviation of brightness)/(average brightness) is 0.486, and irregularity in brightness be evaluated as C (table 2).

Embodiment 8-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 32.0mm.As a result of, average brightness is 10, and 430cd, the standard deviation of brightness are 4,825cd, the value of (standard deviation of brightness)/(average brightness) is 0.463, and irregularity in brightness be evaluated as C (table 2).

Embodiment 9-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 5.0mm.As a result of, average brightness is 10, and 090cd, the standard deviation of brightness are 5,438cd, the value of (standard deviation of brightness)/(average brightness) is 0.539, and irregularity in brightness be evaluated as C (table 2).

Embodiment 10-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 8.0mm.As a result of, average brightness is 10, and 320cd, the standard deviation of brightness are 5,016cd, the value of (standard deviation of brightness)/(average brightness) is 0.486, and irregularity in brightness be evaluated as C (table 2).

Embodiment 11-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 12.0mm.As a result of, average brightness is 10, and 500cd, the standard deviation of brightness are 4,959cd, the value of (standard deviation of brightness)/(average brightness) is 0.472, and irregularity in brightness be evaluated as C (table 2).

Comparative example 4-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 21.0mm.As a result of, average brightness is 10, and 250cd, the standard deviation of brightness are 8,744cd, the value of (standard deviation of brightness)/(average brightness) is 0.853, and irregularity in brightness be evaluated as D (table 2).

Embodiment 12-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 30.0mm.As a result of, average brightness is 10, and 210cd, the standard deviation of brightness are 4,911cd, the value of (standard deviation of brightness)/(average brightness) is 0.481, and irregularity in brightness be evaluated as C (table 2).

Embodiment 13-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 34.0mm.As a result of, average brightness is 10, and 370cd, the standard deviation of brightness are 4,889cd, the value of (standard deviation of brightness)/(average brightness) is 0.471, and irregularity in brightness be evaluated as C (table 2).

Comparative example 5-B

Prepare back light unit and measure brightness with the method identical with embodiment 7-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 45.0mm.As a result of, average brightness is 10, and 210cd, the standard deviation of brightness are 8,382cd, the value of (standard deviation of brightness)/(average brightness) is 0.821, and irregularity in brightness be evaluated as D (table 2).

When " d " that adopt equation (1) calculating optimum made f (p)=p/4 or f (p)=3 * p/4, under the condition of embodiment 7-B to 13-B and comparative example 4-B and 5-B, " d " was calculated as 10.4mm or 31.1mm; And obtained the desired value (being not more than 0.540) of (standard deviation of brightness)/(average brightness), and in 5.4 to 15.4mm or 26.1 to 36.1mm scope, irregularity in brightness be evaluated as B or C.

Embodiment 14-B

Prepare back light unit and measure brightness with the method identical with embodiment 1-B, difference is to use the optical function sheet with recessed square pyramid pattern transferring to replace having the optical function sheet of recessed half quadrangle pyramid pattern transferring (Fig. 9), so that the angle between the orientation direction of the aligning direction of the prism of optical function sheet and cold-cathode tube is the mode of 18.4 ° (Figure 13) the optical function sheet is set, and the distance " d " between cold-cathode tube and the optical function sheet is changed into 16.3mm.As a result of, average brightness is 9, and 410cd, the standard deviation of brightness are 2,430cd, the value of (standard deviation of brightness)/(average brightness) is 0.258, and irregularity in brightness be evaluated as A (table 2).

Embodiment 15-B

Prepare back light unit and measure brightness with the method identical with embodiment 14, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 27.0mm.As a result of, average brightness is 9, and 190cd, the standard deviation of brightness are 2,834cd, the value of (standard deviation of brightness)/(average brightness) is 0.308, and irregularity in brightness be evaluated as A (table 2).

Comparative example 6-B

Prepare back light unit and measure brightness with the method identical with embodiment 14, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 5.0mm.As a result of, average brightness is 9, and 180cd, the standard deviation of brightness are 5,456cd, the value of (standard deviation of brightness)/(average brightness) is 0.594, and irregularity in brightness be evaluated as D (table 2).

Embodiment 16-B

Prepare back light unit and measure brightness with the method identical with embodiment 14-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 14.0mm.As a result of, average brightness is 9, and 050cd, the standard deviation of brightness are 2,766cd, the value of (standard deviation of brightness)/(average brightness) is 0.306, and irregularity in brightness be evaluated as B (table 2).

Embodiment 17-B

Prepare back light unit and measure brightness with the method identical with embodiment 14-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 18.0mm.As a result of, average brightness is 9, and 260cd, the standard deviation of brightness are 2,590cd, the value of (standard deviation of brightness)/(average brightness) is 0.280, and irregularity in brightness be evaluated as A (table 2).

Embodiment 18-B

Prepare back light unit and measure brightness with the method identical with embodiment 14-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 22.0mm.As a result of, average brightness is 9, and 560cd, the standard deviation of brightness are 4,000cd, the value of (standard deviation of brightness)/(average brightness) is 0.418, and irregularity in brightness be evaluated as C (table 2).

Embodiment 19-B

Prepare back light unit and measure brightness with the method identical with embodiment 14-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 25.0mm.As a result of, average brightness is 9, and 440cd, the standard deviation of brightness are 2,898cd, the value of (standard deviation of brightness)/(average brightness) is 0.307, and irregularity in brightness be evaluated as B (table 2).

Embodiment 20-B

Prepare back light unit and measure brightness with the method identical with embodiment 14-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 29.0mm.As a result of, average brightness is 9, and 640cd, the standard deviation of brightness are 2,910cd, the value of (standard deviation of brightness)/(average brightness) is 0.302, and irregularity in brightness be evaluated as B (table 2).

Embodiment 21-B

Prepare back light unit and measure brightness with the method identical with embodiment 14-B, difference is the distance " d " between cold-cathode tube and the optical function sheet is changed into 34.0mm.As a result of, average brightness is 9, and 090cd, the standard deviation of brightness are 4,894cd, the value of (standard deviation of brightness)/(average brightness) is 0.538, and irregularity in brightness be evaluated as C (table 2).

When " d " that adopt equation (1) calculating optimum made f (p)=p/ (18.4 ° of 8 * sin) or f (p)=p/ (18.4 ° of 5 * sin), under the condition of embodiment 14-B to 21-B and comparative example 6-B, " d " was calculated as 16.4mm or 26.3mm; And obtained the desired value (being not more than 0.540) of (standard deviation of brightness)/(average brightness), and in 11.4 to 21.4mm and 21.3 to 31.3mm scope, irregularity in brightness be evaluated as A, B or C.

The figure of Figure 37 has shown the relation (the analog computation result that inhomogeneities is estimated) between the standard deviation (irregularity in brightness) from line source to distance " d " between the optical function sheet and brightness; Wherein the bottom surface aspect ratio AR that is shaped as of prism 4 is 1.5 half quadrangle pyramid (Fig. 9), forms v-depression (Figure 14), and the bottom surface aspect ratio AR that is shaped as of prism 4 is 1.0 square pyramid (Figure 13).It is believed that, be not more than when the optimum value (local lowest standard deviation value) of the luminance standard deviation of vertical axis in as figure in 500 the scope, and the permissible range of " d " is considered to, and (when (optimum value of " d " that is obtained by equation (1)) ± 5mm), effect is enough.In this, consider typical reflecting plate, virtual image quantity increases, therefore the lower limit of the permissible range of preferred " d " reduces 3mm ((optimum value of " d " that is obtained by equation (1))-8mm), and consider typical diffusing panel or diffusing panel, also the upper limit of the permissible range of preferred " d " increases 3mm ((optimum value of " d " that is obtained by equation (1))+8mm).

Table 2

	Prism shape	Apart from d (mm)	The inclination angle (°)	AB (cd)	SDB (cd)	SDB/AB	Irregularity in brightness
								Embodiment 1-B	CSP	13.5	0	9,240	3,220	0.348	B
Embodiment 2-B	CSP	28.5	0	9,310	3,240	0.348	B
								Comparative example 1-B	CSP	5.0	0	9,180	5,020	0.547	D
Embodiment 3-B	CSP	11.0	0	9,370	3,530	0.377	C
								Embodiment 4-B	CSP	16.0	0	9,100	3,470	0.381	B
Comparative example 2-B	CSP	21.0	0	9,150	5,560	0.608	D
								Embodiment 5-B	CSP	26.0	0	9,220	3,470	0.376	B
Embodiment 6-B	CSP	31.0	0	9,160	3,530	0.385	C
								Comparative example 3-B	CSP	45.0	0	9,150	8,380	0.916	D
Embodiment 7-B	1 V sheet	9.8	0	10,130	4,920	0.486	C
								Embodiment 8-B	1 V sheet	32.0	0	10,430	4,825	0.463	C
Embodiment 9-B	1 V sheet	5.0	0	10,090	5,438	0.539	C
								Embodiment 10-B	1 V sheet	8.0	0	10,320	5,016	0.486	C
Embodiment 11-B	1 V sheet	12.0	0	10,500	4,959	0.472	C
								Comparative example 4-B	1 V sheet	21.0	0	10,250	8,744	0.853	D
Embodiment 12-B	1 V sheet	30.0	0	10,210	4,911	0.481	C
								Embodiment 13-B	1 V sheet	34.0	0	10,370	4,889	0.471	C
Comparative example 5-B	1 V sheet	45.0	0	10,210	8,382	0.821	D
								Embodiment 14-B	CRFP	16.3	18.4	9,410	2,430	0.258	A
Embodiment 15-B	CRFP	27.0	18.4	9,190	2,834	0.308	A
								Comparative example 6-B	CRFP	5.0	18.4	9,180	5,456	0.594	D

Embodiment 16-B	CRFP	14.0	18.4	9,050	2,766	0.306	B
								Embodiment 17-B	CRFP	18.0	18.4	9,260	2,590	0.280	A
Embodiment 18-B	CRFP	22.0	18.4	9,560	4,000	0.418	C
								Embodiment 19-B	CRFP	25.0	18.4	9,440	2,898	0.307	B
Embodiment 20-B	CRFP	29.0	18.4	9,640	2,910	0.302	B
								Embodiment 21-B	CRFP	34.0	18.4	9,090	4,894	0.538	C

CSP: recessed half quadrangle pyramid (Fig. 9)

1 V sheet: 1 prismatic lens (Figure 14) with v-depression

CRFP; Recessed square pyramid (Figure 13)

Industrial usability

Can improve the inhomogeneities of light diffusion function and reduction line source according to back light unit of the present invention, and do not reduce light-focusing function, do not produce secondary lobe or reduce productivity ratio etc., therefore, the luminous efficiency and/or the luminescent properties that can be suitably be used for the various displays, display unit, luminescent system etc. of control liquid crystal display systems, organic EL etc.

Become about 170 ° and vapor deposited metal by the drift angle that makes optical function sheet backlight, described optical function sheet can be used as reflecting plate. Thereby, can the Dimming inhomogeneities, can improve utilization ratio, and can prevent Moire fringe (Figure 35,36).

Claims

1. back light unit, it comprises:

A plurality of line sources and

The optical function sheet,

Wherein said line source is launched light to described optical function sheet,

On at least one surface of described optical function sheet, form prism structure with a plurality of prisms, and (H _N-1+ H _n)/(A _n-A _N-1) value about equally,

Wherein, in the intensity map of the Luminance Distribution in showing described optical function sheet, B _MaximumBe high-high brightness with respect to the part on the described optical function sheet of the core of described back light unit, and B _MinimumBe minimum brightness with respect to the part on the described optical function sheet of the core of described back light unit; A ₁Be the peak position of first virtual image, and H ₁Be the peak height of first virtual image, A ₂Be the peak position and the H of second virtual image of contiguous first virtual image ₂Be the peak height of second virtual image of contiguous first virtual image,----, A _N-1Be the peak position and the H of (n-1) virtual image of contiguous (n-2) virtual image _N-1Be the peak height of (n-1) virtual image of contiguous (n-2) virtual image, A _nBe the peak position and the H of (n) virtual image of contiguous (n-1) virtual image _nBe the peak height of (n) virtual image of contiguous (n-1) virtual image, and these virtual images obtain by described a plurality of line sources, and

The described virtual image and its peak height H _nSatisfy H _n〉=0.3 * (B _Maximum-B _Minimum) the peak correspondence of condition; And described intensity map is illustrated in the Luminance Distribution that described back light unit not only be not equipped with diffusion disk but also be not equipped with described optical function sheet under the situation of diffusing panel,

Select the distance ' ' d ' ' between described line source and the described optical function sheet, feasible (H _N-1+ H _n)/(A _n-A _N-1) the value constant.

2. back light unit according to claim 1, wherein, the ratio of the distance between the peak position of the summation of the described peak height of the virtual image of the described peak height of a virtual image among the described a plurality of virtual images that obtained by described a plurality of line sources and a contiguous described virtual image and described adjacent image about equally.

3. back light unit, it comprises:

A plurality of line sources and

The optical function sheet,

Wherein said line source is launched light to described optical function sheet,

On at least one surface of described optical function sheet, form prism structure with a plurality of prisms,

The virtual image of the described optical function sheet that is obtained by described a plurality of line sources has brightness about equally, and

Distance between the contiguous virtual image of described optical function sheet about equally,

Select the distance ' ' d ' ' between described line source and the described optical function sheet, make in the described optical function sheet between the contiguous virtual image apart from constant.

4. back light unit according to claim 3, wherein, in the intensity map of the Luminance Distribution in showing described optical function sheet, at R ₁To R _nEach zone in exist quantity about equally and luminance peaks highly about equally with about equally interval,

Wherein, R ₁Be the zone of secondary light source among described a plurality of line sources from first light source to contiguous first light source, R ₂Be the zone of the 3rd light source from secondary light source to contiguous secondary light source,---, R _N-1Be the zone of (n) light source from (n-1) light source to contiguous (n-1) light source, and R _nIt is the zone of (n+1) light source from (n) light source to contiguous (n) light source.

5. back light unit according to claim 1, wherein said back light unit also comprises diffusion disk, in the region R of described optical function sheet _nThe standard deviation value of inner brightness is divided by the region R of described optical function sheet _nInner average brightness is less than 0.0100,

6. back light unit according to claim 1, wherein the aligning direction of prism favours the orientation direction of described line source.

7. back light unit according to claim 1, wherein, the ratio of the distance between the peak position of the summation of the described peak height of the virtual image of the described peak height of a virtual image among the described a plurality of virtual images that obtained by described a plurality of line sources and a contiguous described virtual image and described adjacent image about equally.

8. back light unit according to claim 1 is wherein in the region R of described optical function sheet _nThe standard deviation value of inner brightness is divided by the described region R of described optical function sheet _nInner average brightness is not more than 0.540,

9. back light unit according to claim 1, wherein based on the described surface of emission of the refractive index " n " of described optical function sheet, described prism with respect to oblique angle θ from the light of described line source emission, and the spacing of described line source " p ", by the distance ' ' d ' ' of following equation (1) calculating between described line source and described optical function sheet

D=(f (p)-27.9n-0.473 θ+65.7)/0.557 ± 5mm equation (1)

Wherein f (p) is nodal line and the distance between the virtual image of approaching described nodal line, and is the function of described spacing " p "; Wherein said nodal line be comprise among described a plurality of line source line source and perpendicular to the plane of described optical function sheet with comprise a line between the plane of described optical function sheet; The described virtual image is the virtual image the virtual image on described nodal line among the described virtual image of the described optical function sheet that is obtained by line source.

10. back light unit according to claim 9, each of wherein said prism is half quadrangle pyramid, and have reciprocal two first surface of emissions, and reciprocal two second surface of emissions, one area in the area summation of described two first surface of emissions and described two second surface of emissions about equally, and when the aligning direction of described prism was parallel to the orientation direction of described line source, f (P) was about p/3 or about 2p/3

11. back light unit according to claim 1 described optical function sheet with described prism of being with v-depression wherein is set, and when the aligning direction of described prism was parallel to the orientation direction of described line source, f (P) was about p/4 or about 3p/4,

12. back light unit according to claim 1, each of wherein said prism is the square pyramid, and when the aligning direction of described prism during from X ° of the orientation direction inclination of described line source, f (p) is about p/ (8 * sin X °) or about p/ (5 * sin X °)

13. back light unit according to claim 1, wherein said back light unit also comprises another optical function sheet, and the quadrature setting has described two optical function sheets of the described prism of band v-depression, and when the aligning direction of the described prism of an optical function sheet during from X ° of the orientation direction inclination of described line source, f (p) is about p/ (8 * sin X °+8 * cos X °) or about p/ (6.5 * sin X °+6.5 * cos X °)