JP2007087900A - Backlight system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with a large backlight system having a large light emitting area with a light source having a small light emitting area, and the system can be reduced in size and weight.
The backlight system includes a planar light source L having a light emitting surface 21 having an area SL smaller than an area SB of the light emitting surface 22 and light from the light emitting surface of the planar light source. Light magnifying means 12 for magnifying to the area of the light emitting surface of the system before reaching the light emitting surface is provided.
[Selection] Figure 5

Description

  The present invention relates to a backlight system such as a liquid crystal display.

  As a flat fluorescent lamp mounted on a backlight system for a liquid crystal display, one shown in FIGS. 1 and 2 of JP-A-2005-32722 (Patent Document 1) is known. This conventional flat fluorescent lamp is referred to as a surface light source device 100 in this document. The front plate surface light source device 100 includes a light source body 110, a space dividing wall 120, and a discharge voltage application unit 130. The light source body 110 has a flat space 112. The light source body is disposed with the bottom surface 110a and the light emitting surface 110f facing each other, and the periphery thereof is surrounded by side walls 110b, 110c, 110d, and 110e to form a discharge vessel. At least one or more space dividing walls 120 are disposed inside the light source body 110, and a plurality of discharge spaces are formed. The pair of discharge voltage application units 130 are arranged in a direction perpendicular to the length direction of the space dividing wall 120. The discharge gas 114 contains one or more of trace amounts of argon, neon, xenon, and krypton together with mercury. The fluorescent layer 116 is formed in the form of a thin film on the inner wall of the light source body 110 and the surface of the space dividing wall 120. The phosphor layer 116 converts ultraviolet rays generated from the discharge gas 114 into visible light. The light reflecting layer 199 is formed on the inner surface of the bottom surface 110a and the side walls 110b, 110c, 110d, and 110e, and reflects the light generated from each discharge space to the light emitting surface f. The discharge voltage application unit 130 is disposed on the surface of the light source body 110 in order to cause discharge inside the light source body 110. The discharge voltage application unit 130 is arranged in a direction perpendicular to the length direction of the space dividing wall 120.

  FIG. 47 of Patent Document 1 shows a backlight assembly using the flat fluorescent lamp. The backlight assembly includes a surface light source device 100, a storage container 200, and an optical member 300. The storage container 200 includes a storage container bottom surface 210, a storage container side wall 220, a discharge voltage application unit module 230, and an inverter 240. The storage container bottom surface 210 has a bottom area sufficient for bonding the surface light source device 100 and the same shape as the surface light source device 100. The storage container bottom surface 210 has a rectangular parallelepiped plate shape in the same manner as the bottom surface 110 a of the surface light source device 100. The container side wall 220 is extended from the container bottom surface 210 so that the surface light source device 100 is not detached outside. The discharge voltage application module 230 applies a discharge voltage to the discharge voltage application unit 130 of the surface light source device 100. The discharge voltage application module 230 includes a first voltage application module 232 and a second discharge voltage application module 234. The first discharge voltage application module 232 includes a first conductive body 232a and a first conductive clip 232b formed on the first conductive body 232a. The second discharge voltage application module 234 includes a second conductive body 234a and a second conductive clip 234b formed on the second conductive body 234a. The pair of discharge voltage application units 130 formed in the surface light source device 100 are clipped and fixed to the first conductive clip 232b and the second conductive clip 234b. The inverter 240 applies a discharge voltage to the first discharge voltage application module 232 and the second discharge voltage application module 234. The inverter 240 and the first discharge voltage application module 232 are connected by a first power supply application line 242, and the inverter 240 and the second discharge voltage application module 234 are connected by a second power supply application line 244. Since the luminance is reduced where the dividing wall 120 is located in the surface light source device 100, an optical member 300 is disposed on the upper surface of the surface light source device 100 in order to improve the luminance distribution. The optical member 300 is a diffusing plate that diffuses light generated from the surface light source device 100 to make the luminance distribution more uniform.

  In recent years, with the widespread use of large LCD TVs, the size of backlight systems has been increasing. In order to cope with this, in the case of a backlight system using a conventional flat fluorescent lamp as shown in FIG. 47 of Patent Document 1, the light emitting area on the diffusion plate, which is the light emitting surface of the backlight system, Since the light emitting area of the flat fluorescent lamp as the light source is substantially equal, the flat fluorescent lamp as the light source needs to be enlarged to the same size as the backlight increases.

However, when the flat fluorescent lamp becomes larger,
(A) When manufacturing a lamp, a large-scale manufacturing facility is required, which increases the cost of the lamp.
(B) Since the distance between the electrodes of the lamp increases and the applied voltage becomes high, there is a limit to the enlargement of the lamp.
(C) Since the amount of the glass member used increases, the lamp becomes heavy and the backlight cannot be reduced in weight.
Cause problems.

  Further, in the case of a lamp configured to enclose mercury as an ultraviolet ray source of the above flat fluorescent lamp, the brightness of the fluorescent lamp is greatly influenced by the vapor pressure of the enclosed mercury, that is, the tube wall temperature of the lamp, Since the lamp tube wall temperature at which the luminous efficiency is maximized has a characteristic of 50 to 60 ° C., the following problems occur when the lamp is enlarged.

One of the problems is that since the heat capacity of the glass material constituting the discharge vessel is increased, the rise of the tube wall temperature is slow and the rise rate of the brightness is slow even when power is supplied to the lamp. Another problem is that the input power per lamp light emitting area is low and the heat radiation area of the glass member is large, so that it is difficult to reach the optimum tube wall temperature for the light emitting efficiency, resulting in the lamp light emitting efficiency being lowered. It is.
Japanese Patent Laying-Open No. 2005-32722

  The present invention has been made in view of the above-mentioned problems of the prior art. Even for a large backlight system having a large light emitting area, the light source has a light emitting surface with a light emitting area smaller than the light emitting area of the system. It is an object of the present invention to provide a backlight system that can be handled by what it has, and that can solve the above-mentioned problems of the prior art.

  A backlight system according to a first aspect of the present invention includes a planar light source having a light emitting surface area smaller than the light emitting surface area of the backlight system, and light from the light emitting surface of the planar light source. And a light magnifying means for magnifying the area of the light emitting surface of the system before reaching the light emitting surface.

  According to a second aspect of the present invention, in the backlight system of the first aspect, a predetermined interval is provided between the light emitting surface of the planar light source and the light emitting surface of the backlight system as the light expanding means. It is what.

  According to a third aspect of the present invention, in the backlight system of the first aspect, as the light expanding means, a predetermined interval is provided between the light emitting surface of the planar light source and the backlight light emitting surface of the system, and A light expanding optical lens is installed on the backlight emission surface of the system.

  According to a fourth aspect of the present invention, in the backlight system of the third aspect, the optical lens is a combination of one or more of a lens, a Fresnel lens, a linear Fresnel lens, and a prism sheet. is there.

  According to a fifth aspect of the present invention, in the backlight system according to any one of the first to fourth aspects, the light diffusing means is disposed on the backlight irradiation surface side of the light expanding means.

  According to a sixth aspect of the present invention, in the backlight system of the fifth aspect, the light diffusion means is a diffusion plate or a diffusion sheet.

  The invention according to claim 7 is the backlight system according to any one of claims 1 to 6, wherein a side wall having a slope shape is disposed between the light emitting surface of the planar light source and the irradiation surface of the backlight. It is.

  According to an eighth aspect of the present invention, in the backlight system of the seventh aspect, the non-light-emitting portion of the planar light source is shielded from light on the side wall.

  A ninth aspect of the invention is the backlight system of the eighth aspect, wherein the non-light emitting portion of the planar light source shielded on the side wall is an electrode portion or a side wall portion of the planar light source. .

  A tenth aspect of the present invention is the backlight system according to the seventh to ninth aspects, wherein a lighting circuit for the planar light source is housed on the back side of the side wall.

  The invention of claim 11 is the backlight system of claims 1 to 10, wherein a plurality of the planar light sources are arranged.

  According to a twelfth aspect of the present invention, in the backlight system of the eleventh aspect, a plurality of the light magnifying means are arranged.

  The invention of claim 13 is the backlight system of claim 11 or 12, characterized in that the plurality of planar light sources are separated by side walls.

  According to a fourteenth aspect of the present invention, in the backlight system of the thirteenth aspect, the height of the side wall of the adjacent section of the planar light source is set to be greater than the distance between the irradiation surface of the planar light source and the irradiation surface of the backlight. It is characterized by being shortened.

  The invention of claim 15 is the backlight system of claims 11 to 14, wherein the plurality of planar light sources emit light simultaneously.

  A sixteenth aspect of the present invention is the backlight system according to any one of the eleventh to fourteenth aspects, wherein the plurality of planar light sources emit light so that their light emission periods are different from each other.

  The invention according to claim 17 is the backlight system according to any one of claims 1 to 16, wherein the planar light source is a planar fluorescent lamp or a small backlight combining a light source and an optical member. .

  The invention according to claim 18 is the backlight system according to claim 17, wherein the planar light source is a light source using mercury.

  The invention according to claim 19 is the backlight system according to claims 1 to 15, wherein the planar light source is a single LED, a single LED dispersed or a light source in which LEDs are linearly or planarly integrated, or It is the backlight used.

  The backlight system of the present invention is characterized in that a planar light source having a light emitting surface smaller than the light emitting surface area of the backlight system is mounted, and the light emitting surface of the system Even if the area of the light source increases, it is possible to cope with a light source having a light emitting surface of a smaller area, and the cost and weight of the backlight system can be reduced by reducing the cost and weight of the light source.

  Further, according to the present invention, even if the area of the light emitting surface is increased as a backlight system, it can be handled by a light source having a light emitting surface of a smaller area. Therefore, when mercury is used as the light source of the light source, The amount of glass used can be reduced from the above configuration, the tube wall temperature can be easily reached to the optimum value of luminous efficiency of 50-60 ° C, the brightness rise speed is fast, and a highly efficient backlight system is provided. Can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) FIGS. 1 to 3 show a flat fluorescent lamp L as a flat light source mounted on a backlight system according to one embodiment of the present invention. In the flat fluorescent lamp L of the present embodiment, a front substrate 1 made of a translucent glass plate and a rear substrate 2 integrally formed with a side wall 3 and a spacer 5 are opposed to each other at a substantially constant interval. The peripheral portion is sealed with frit glass 7 to form a flat discharge vessel structure.

  In this flat fluorescent lamp L, mercury vapor as a discharge medium, one gas of xenon, krypton, argon, neon, helium, or two or more kinds of gases are mixed, and from several kPa It is sealed at a sealing pressure of several hundred kPa. As an example of the sealed gas, mercury vapor and a mixed gas of argon and neon can be given. In that case, the ratio of neon to argon is 50:50 to 99: 1 when the luminous efficiency and low voltage starting of the lamp are prioritized, and the composition of the neon is increased, and the rising speed of the light is prioritized. Can be configured to increase the argon compounding ratio from 1:99 to 50:50. The gas pressure is in the range of 1 Torr to 700 Torr, and is preferably set in the range of 20 to 100 Torr from the viewpoint of low voltage startability, luminous efficiency, and life.

  On the outer surface of the front substrate 1, an external electrode 6a for applying a high voltage and an external electrode 6b for applying a low voltage are arranged along the end of the discharge vessel so as not to contact the discharge medium. In the present embodiment, the external electrodes 6a, 6b and the discharge medium are blocked by the front substrate 1 itself, which is a glass material, but may be blocked using a dielectric layer. In the present embodiment, both electrodes 6a and 6b are shielded from the discharge medium, but one electrode may be an internal electrode and only the other electrode may be shielded from the discharge medium. In the present embodiment, the external electrodes 6 a and 6 b are provided only on the front substrate 1, but the external electrodes are formed only on the rear substrate 2 or on both the front substrate 1 and the rear substrate 2. It is possible to adopt a configuration or a configuration in which the front substrate 1, the rear substrate 2, and the side surface where the front substrate 1 and the rear substrate 2 are joined are also formed.

  As an electrode forming method, a method of forming a conductive tape such as aluminum on a discharge vessel via a conductive adhesive, or screen printing a conductive paste in which a metal powder such as silver, a solvent and a binder are mixed, After being applied to the surface of the discharge vessel by applying a dispenser or dipping, drying and baking are performed, and solder containing at least one of tin, indium, bismuth, lead, zinc, antimony, or silver is heated and melted. For example, a method of applying a product to the surface of the discharge vessel by a dispenser or immersion while applying ultrasonic vibration can be employed. In order to improve the adhesion between the electrode layer and the discharge vessel, a method can be used in which the surface of the discharge vessel at the position where the electrode is formed is made uneven by, for example, sandblasting.

  The external electrodes 6a and 6b can have various different shapes such as forming a convex portion toward each discharge space 8 separated by the spacer 5 in addition to the strip shape shown in the figure. Further, although a pair of electrodes is shown in the figure, a plurality of pairs of electrodes may be used.

  The elongated spacers 5 formed integrally with the rear substrate 2 are arranged at a predetermined interval, and the distance between the front substrate 1 and the rear substrate 2 is kept constant, and at the same time the lamp due to the pressure difference between the inside and outside of the discharge vessel is maintained. Prevent damage from implosion. The spacer 5 is arranged in a direction perpendicular to the electrodes 6 a and 6 b and divides the electrodes 6 a and 6 b into a plurality of discharge spaces 8.

  In addition to the trapezoidal cross section shown in the figure, the spacer 5 can have an arbitrary shape such as a wave shape as shown in FIG. 4A and a semi-elliptical shape as shown in FIG. Moreover, as shown in FIG.4 (c), it can also be set as the structure which made the front substrate 1 and the back substrate 2 flat plate shape, and provided the spacer 5 separately. In the present embodiment, the rear substrate 2 is integrally formed by thermal processing. However, as shown in FIGS. 4D and 4E, the front substrate 1 is thermally processed to form a flat rear substrate. 2 and a configuration in which the front substrate 1 and the rear substrate 2 are bonded together by thermal processing as shown in FIG.

  The size of the discharge space 8 divided by the spacer 5 is set according to the required starting voltage / tube voltage and light amount of the lamp. For example, the width W of the discharge space 8 is in the range of 0.5 to 30 mm. The height H of the discharge space 8 is set in the range of 0.5 to 6 mm. Although FIG. 4 illustrates a case where the areas of the divided discharge spaces 8 are all the same, the cross-sectional area of the discharge space may be different depending on the location.

  A phosphor layer 4 is formed inside each of the front substrate 1, the back substrate 2, and the spacer 5. The phosphor layer 4 converts ultraviolet rays radiated from the discharge medium by discharge into visible light. The phosphor layer 4 uses phosphors used in general illumination, cold cathode fluorescent lamps, and PDPs, and is coated with several kinds of phosphors having different emission colors. In addition, the fluorescent substance layer 4 can also be comprised by apply | coating the fluorescent substance of a different luminescent color separately in stripe shape or dot shape.

  The phosphor layer 4 of the front substrate 1 on the light extraction side has, for example, an average particle size (primary particle size) of about 2.5 μm or more in order to transmit the phosphor light from the back substrate 2 side without loss. The phosphor particles are formed as thin as 5 to 15 μm. On the other hand, the phosphor layer 4 of the back substrate 2 from which light is not extracted has a thickness of 30 to 100 μm, for example, with a phosphor particle having an average particle size of about 2.5 μm or less in order to guide much light to the front substrate 1 side. The thickness is increased to increase the reflection luminance. Although not shown, in the substrate 1 on which the electrodes 6a and 6b are formed, when the phosphor layer 4 is inside the substrate at the position where the electrode is formed, the phosphor layer 4 is sputtered by discharge and gas In general, the phosphor layer is not provided inside the substrate 1 where the electrodes 6a and 6b are provided.

  Between the back substrate 2 and the phosphor layer 4, a fine metal oxide reflective layer can be formed. In addition, a metal oxide layer such as titanium oxide, aluminum oxide, yttrium oxide is formed between the front substrate 1 and the rear substrate 2 and the phosphor layer 4 to prevent mercury from moving to the glass surface. It is also possible to absorb ultraviolet rays generated from discharge. Furthermore, in this Embodiment, although the fluorescent substance layer 4 is provided in the inner surface of the board | substrates 1 and 2 of both glass materials, it can also be set as the structure which abbreviate | omits either fluorescent substance layer. Further, the phosphor layer 4 on both the front substrate 1 and the rear substrate 2 can be omitted, and the visible light emitted from the discharge medium can be directly used.

  By applying a rectangular wave voltage, a triangular wave voltage, a sine wave voltage or a pulse voltage having a frequency of 10 to 200 kHz between the high-voltage side external electrode 6a and the low-voltage side external electrode 6b, mercury in the discharge distribution space is applied. In addition, the rare gas is excited to cause discharge to generate ultraviolet rays, and this is irradiated onto the phosphor to emit visible light, which is emitted to the outside.

  A backlight system using the planar light source L is shown in FIGS. The casing of the backlight system includes a front frame 11a and a back frame 11b. The planar light source L is arranged at a distance of 0.1 mm to 5 mm from the bottom surface of the back frame 11b of the backlight system. The light emitting area SL of the light emitting surface 21 of the flat light source L is set smaller than the light emitting area SB of the light emitting surface 22 of the backlight system. The light emitting area ratio SL / SB is preferably set to 0.95 to 0.2.

  Since the light emission area SL of the planar light source L is smaller than the light emission area SB of the backlight system, a side wall 12 having a slope shape is arranged around the planar light source L to efficiently guide light to the backlight light emitting surface 21. The light emission uniformity of the backlight system is improved. Further, since there is a free space on the back surface of the side wall 12, for example, the side wall and the electrodes 6a and 6b, which are non-light emitting portions of the flat light source L, are shielded by the side walls, and the lighting circuit 16 of the flat light source L is accommodated. Thus, the backlight system can be made thin.

  Further, in order to further improve the light emission uniformity of the lamp, a diffuser plate 13 having a transmittance of 40% or more is arranged on the front substrate 1 side of the flat light source L with an interval of about 0.1 to 30 mm. Yes. Furthermore, an optical sheet 14 such as a diffusion sheet, a condensing sheet, and a polarization reflection sheet is disposed on the upper surface of the diffusion plate 13 in order to improve the light emission uniformity and luminance. This optical sheet 14 is employed when necessary.

  By increasing the distance DL from the planar light source L to the diffusion plate 13, even if the light emission area SL of the planar light source L is reduced, the light emission of the light emitting surface 22 of the backlight system can be made uniform.

  In the backlight system according to the first embodiment having the above-described configuration, the light emitted from the planar light source L is emitted by providing a distance DL between the light emitting surface 21 of the planar light source L and the light emitting surface 22 of the system. Since the light is diffused and emitted to the light emitting surface 22 of the system and then emitted as a backlight from there, the light emitting area SL of the light emitting surface 21 of the flat light source L is set to the light emitting surface 22 of the backlight system. The light emitting area SB can be made smaller, so that even when the light emitting area SB of the backlight system is increased, the planar light source L does not need to have the same size, and a small one can be adopted. As a result, the cost and weight of the backlight system can be reduced by reducing the cost and weight of the light source. Moreover, even if the area of the light emitting surface is increased as a backlight system, it can be handled by a planar light source having a light emitting surface of a smaller area. Therefore, when mercury is used as the light source of the light source, the conventional configuration The amount of glass used can be reduced, the tube wall temperature can easily reach the optimum luminous efficiency value of 50 to 60 ° C., the brightness rise speed is fast, and a highly efficient backlight system can be realized.

  (Second Embodiment) FIGS. 7 and 8 show a backlight system according to a second embodiment of the present invention. In the backlight system of the present embodiment, instead of the optical sheet 14 in the first embodiment, a plate or sheet, for example, a lens, in which grooves are formed linearly or circularly on the surface as light expanding means there. A light expanding sheet 15 or a plate in which one or more prism sheets are combined with a Fresnel lens or a linear Fresnel lens is provided. The planar light source L employed in the present embodiment is the same as that employed in the first embodiment, and is the planar fluorescent lamp shown in FIGS. In FIGS. 7 and 8, elements common to the first embodiment are denoted by common reference numerals.

  The casing of the backlight system includes a front frame 11a and a back frame 11b. The planar light source L is disposed at a distance of 0.1 mm to 5 mm from the bottom surface of the back case 11b of the backlight. The light emitting area SL of the light emitting surface 21 of the flat light source L is set smaller than the light emitting area SB of the light emitting surface 22 of the backlight system. The light emission area ratio SL / SB is set to 0.95 to 0.2.

  Since the light emission area SL of the flat light source L is smaller than the light emission area SB of the backlight, a side wall 12 having a slope shape is disposed around the flat light source L to efficiently guide light to the backlight light emitting surface. The light emission uniformity of the light system is improved. On the front substrate 1 side of the planar light source L, a light expanding sheet 15 is arranged with an interval of about 0.1 to 30 mm.

  According to the present embodiment, the light from the light source L can be greatly expanded by replacing the optical sheet 14 with the light expansion sheet 15 as compared with the case of the first embodiment. The light emission area SL can be reduced further. In the case where the light expanding sheet 15 is used, since the light emitted from the backlight system has a finger-lighting property in a certain direction, the diffusion sheet similar to the first embodiment is further above the light expanding sheet 15, An optical sheet such as a diffusion plate may be disposed.

  (Third Embodiment) Next, a backlight system according to a third embodiment of the present invention will be described with reference to FIGS. In the backlight systems of the first and second embodiments, only one planar light source is mounted. However, the backlight system of the present embodiment has four smaller planar light sources, that is, a planar light source. It is characterized by mounting the mold light sources LA, LB, LC, and LD. In the case of the present embodiment, the total light emitting area SL of the light emitting surfaces 21 of the planar light sources LA, LB, LC, LD is set smaller than the light emitting area SB of the light emitting surface 22 of the backlight system. A plurality of light expansion sheets 15A, 15B, 15C, and 15D are arranged so as to correspond to the respective planar light sources LA, LB, LC, and LD. In FIGS. 9 and 10, elements common to the first and second embodiments are denoted by common reference numerals.

  As a liquid crystal control method using the backlight system of the present embodiment, the liquid crystal screen is divided into a plurality of sections, and the backlight corresponding to each section of the liquid crystal according to the brightness of the image displayed by each section There is a method of controlling the brightness of each section. In this case, if the light emission of the backlight of each section leaks to the adjacent light emission section, the liquid crystal emits white light when attempting to display a black screen. Therefore, in the backlight system of the present embodiment, side walls 12A, 12B, 12C, and 12D having slopes are arranged on the four sides of each of the planar light sources LA, LB, LC, and LD, and light from adjacent light sources is received. Separated so as not to mix. Since there is a free space on the back surface of the side wall 12A and the like, for example, the side walls and the electrodes 6a and 6b, which are non-light emitting portions of the flat light source, are shielded by the side wall 12A or the flat light sources LA, LB and LC. , LD can be housed to house the lighting circuits 16A, 16B, 16C, 16D, and the backlight can be made thin.

  (Fourth Embodiment) A backlight system according to a fourth embodiment of the present invention will be described with reference to FIGS. The feature of the fourth embodiment is that the height HT of the inclined side walls 12A, 12B, 12C, 12D, which is an intermediate partition, is different from that of the light source LA, LB, LC, LD in the third embodiment. The distance DL is lower than the distance DL from the light emitting surface 21 to the light emitting surface 22 of the system. All other configurations are the same as those in the third embodiment. Therefore, in FIGS. 11 and 12, elements common to the third embodiment are denoted by common reference numerals.

  The backlight system of the present embodiment is a system that is turned on with the light emission timings of the plurality of light sources LA, LB, LC, and LD being the same. For this purpose, the side wall 12A of the adjacent section such as the planar light source LA is used. By reducing the height HT, etc., the light emission is guided to the adjacent sections, thereby improving the light emission uniformity of the backlight system.

  In the backlight system of each of the embodiments described above, the flat fluorescent lamp shown in FIGS. 1 to 3 is adopted as the flat light source L. However, in addition to such a flat fluorescent lamp, a tube-type fluorescent lamp is used. A small backlight combining a light source such as a light source or an LED and a light source member, for example, a direct type or an edge type small backlight, can also be used as a planar light source. Moreover, the light source which disperse | distributed LED single-piece | unit, disperse | distributing LED single-piece | unit, or integrated LED linearly or planarly, and a backlight using the same can be used.

The perspective view of the flat fluorescent lamp mounted in the backlight system of the 1st Embodiment of this invention. FIG. 3 is a perspective view in which the flat fluorescent lamp is partially broken. FIG. 3 is a partially broken perspective view seen from the back substrate side of the flat fluorescent lamp. Sectional drawing of the modification of the said planar fluorescent lamp. 1 is an exploded perspective view of a backlight system according to a first embodiment of the present invention. Sectional drawing of the backlight system of the said 1st Embodiment. The disassembled perspective view of the backlight system of the 2nd Embodiment of this invention. Sectional drawing of the backlight system of the said 2nd Embodiment. The disassembled perspective view of the backlight system of the 3rd Embodiment of this invention. Sectional drawing of the backlight system of the said 3rd Embodiment. The disassembled perspective view of the backlight system of the 4th Embodiment of this invention. Sectional drawing of the backlight system of the said 4th Embodiment.

Explanation of symbols

L Planar light source 11a Front frame 11b Back frame 12 Side wall 12A, 12B, 12C, 12D Side wall 13 Diffusion sheet 14 Optical sheet 15 Light expansion sheet 21 Light emission surface 22 Light emission surface

Claims (19)

A planar light source having a light emitting surface area smaller than the light emitting surface area of the backlight system;
And a light expanding means for expanding light from the light emitting surface of the planar light source to the area of the light emitting surface of the system before reaching the light emitting surface of the backlight system. system.   2. The backlight system according to claim 1, wherein a predetermined interval is provided between the light emitting surface of the planar light source and the light emitting surface of the backlight system as the light expanding means.   As the light magnifying means, a predetermined interval is provided between the light emitting surface of the planar light source and the backlight light emitting surface of the system, and a light expanding optical lens is installed on the backlight light emitting surface of the system. The backlight system according to claim 1.   The backlight system according to claim 3, wherein the optical lens is one or a combination of a lens, a Fresnel lens, a linear Fresnel lens, and a prism sheet.   The backlight system according to any one of claims 1 to 4, wherein a light diffusing unit is disposed on a backlight irradiation surface side of the light expanding unit.   The backlight system according to claim 5, wherein the light diffusion means is a diffusion plate or a diffusion sheet.   The backlight system according to claim 1, wherein a side wall having an inclined surface is disposed between the light emitting surface of the planar light source and the irradiation surface of the backlight.   The backlight system according to claim 7, wherein a non-light emitting portion of the planar light source is shielded from light on the side wall.   The backlight system according to claim 8, wherein the non-light-emitting portion of the planar light source shielded on the sidewall is an electrode portion or a sidewall portion of the planar light source.   The backlight system according to claim 7, wherein a lighting circuit for the planar light source is housed on the back side of the side wall.   The backlight system according to claim 1, wherein a plurality of the planar light sources are arranged.   The backlight system according to claim 11, wherein a plurality of the light expanding means are arranged.   The backlight system according to claim 11 or 12, wherein the plurality of planar light sources are separated by side walls.   14. The backlight system according to claim 13, wherein the height of the side wall of the adjacent section of the planar light source is shorter than the distance between the irradiation surface of the planar light source and the irradiation surface of the backlight. .   The backlight system according to claim 11, wherein the plurality of planar light sources emit light simultaneously.   The backlight system according to claim 11, wherein the plurality of planar light sources emit light such that their light emission periods are different from each other.   The backlight system according to claim 1, wherein the planar light source is a planar fluorescent lamp or a small backlight combining a light source and an optical member.   The backlight system according to claim 17, wherein the planar light source is a light source using mercury. 16. The planar light source according to claim 1, wherein the planar light source is a single LED, a light source in which LEDs are dispersed, or a light source in which LEDs are linearly or planarly integrated, or a backlight using the light source. The backlight system described in Crab.

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