KR20100105424A - Edge-light type lighting device - Google Patents

Abstract

B

3.0 × A₁
식 (2) : 1.2 × A₂

B

3.0 × A₂ (Problem) Providing edge light type lighting device that indoors can feel good brightness.
(Solution means) A substantially rectangular light guide plate 1, a light source 2A disposed on at least one side end surface side of the light guide plate 1, and a light source 2A emitted from the light source plate 2A and incident on the side end surface of the light guide plate 1 A substantially rectangular reflective film 3 disposed on the reflective surface side facing the light exit surface of the light guide plate 1 from which light is emitted, and a substantially rectangular light diffuser plate 6 disposed on the exit surface side of the light guide plate 1 An edge light type lighting device (7) having a diffuse reflection portion for diffusely reflecting light on a reflective surface of the light guide plate (1), the light diffusing plate (6) having an outer surface of the light diffusion plate (6). The luminance A _{1 in the} vicinity of any one side of, the luminance A _{2 in the} vicinity of one side opposite to the one side, and the luminance B in the vicinity of the line drawn equidistant from these two opposite sides are represented by the following formulas (1) and (2): Edgelight type lighting device (7), characterized by
Equation (1): 1.2 × A ₁

B

3.0 × A ₁
Equation (2): 1.2 × A ₂

B

3.0 × A ₂

Description

Edgelight type lighting device {EDGE-LIGHT TYPE LIGHTING DEVICE}

The present invention relates to an edge light type lighting device. Such a lighting device is useful as a lighting device used indoors of an office or a house.

A so-called edge light type lighting device includes a light source, a light guide plate for surface emitting light incident from the light source, and a light diffusion plate on the light emitting surface side of the light guide plate, and the luminance of the light exiting from the light diffusion plate is uniform. Lighting devices controlled to be mounted are widely known (for example, see Patent Documents 1 to 6).

Japanese Patent Laid-Open No. 4-257824 Japanese Patent Application Laid-open No. Hei 8-41831 Japanese Patent Application Laid-Open No. 8-41832 Japanese Patent Laid-Open No. 3-5726 Japanese Patent Laid-Open No. 5-196940 Japanese Patent Laid-Open No. 3-256090

However, when a conventional edge light type lighting device is used indoors of an office or a house, the brightness felt by the person indoors is not necessarily sufficient. Accordingly, an object of the present invention is to provide an edge light type lighting device that enables people indoors to feel good brightness.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, the present inventors came to complete this invention which can achieve the said objective. That is, the present invention relates to an approximately rectangular light guide plate, a light source disposed on at least one side end surface side of the light guide plate, a light exit surface of the light guide plate on which light emitted from the light source and incident on the side end surface of the light guide plate is output; A substantially rectangular reflective film disposed on an opposing reflective surface side, and a substantially rectangular optical diffuser disposed on the light emitting surface side of the light guide plate, and having a diffuse reflection portion for diffusely reflecting light on the reflective surface surface of the light guide plate; An edge light type illumination device comprising: a luminance A ₁ near one of the sides of the light diffusion plate, a luminance A ₂ near the one side facing the one side, and these opposing surfaces on an outer surface of the light diffusion plate. An edge light type illuminating device, wherein luminance B near a line drawn at two sides and equidistant satisfies the following formulas (1) and (2).

B

3.0 × A₁ Equation (1): 1.2 × A ₁

B

3.0 × A ₁

B

3.0 × A₂ Equation (2): 1.2 × A ₂

B

3.0 × A ₂

Industrial Applicability According to the present invention, it is possible to provide an edge light type lighting device in which people indoors can feel good brightness. Furthermore, the edge light type illuminating device of the present invention also has good illuminance just under the normal direction, and is particularly preferable as an illuminating device indoors.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the edge light type illuminating device of this invention by which a light source is arrange | positioned at the two opposing side end surface sides of a light guide plate.
2 is a cross-sectional view schematically showing an example of the edge light type lighting device of the present invention in which a light source is arranged on one side end surface side of the light guide plate.
3 is a perspective view schematically showing an example of the lighting apparatus of the present invention in which a light source is disposed on two side end face sides of the light guide plate facing each other.
4 shows an example of the density distribution [vertical axis: dot occupancy density (%), horizontal axis: distance from the side end surface side on which the light source is arranged] of the dot-shaped diffuse reflection portion formed on the reflecting surface of the light guide plate in Example 1; It is a graph.
FIG. 5 shows an example of the density distribution [vertical axis: dot occupancy density (%), horizontal axis: distance from the side end surface side on which the light source is arranged] of the density distribution of the dot-shaped diffuse reflection portion formed on the reflective surface of the light guide plate in Comparative Example 1; It is a graph.
FIG. 6: is a figure which shows the positional relationship of arbitrary one dot and the dot adjacent to the dot (unit of numerical value in drawing is mm).

EMBODIMENT OF THE INVENTION Although the edgelight type illuminating device of this invention is demonstrated referring FIGS. 1-3, this invention is not limited to these. FIG. 1: is sectional drawing which showed typically an example of the edge light type illuminating device of this invention by which a light source is arrange | positioned at two side end surface sides of a light guide plate opposing. FIG. 2: is sectional drawing which showed typically an example of the edge light type lighting apparatus of this invention by which a light source is arrange | positioned at one side end surface side of a light guide plate. 3 is a perspective view schematically showing an example of the edge light type lighting device of the present invention in which a light source is disposed on two side end surface sides of the light guide plate facing each other. 1 to 3, the edge light type lighting device 7 of the present invention includes a light guide plate 1, a light source 2A disposed on at least one side end surface side of the light guide plate 1, and a light source. Reflecting film 3 disposed on the reflecting surface side opposite to the light emitting surface of light guide plate 1 from which light emitted from 2A and incident on the side end surface of light guide plate 1 is emitted, and the light exit surface of light guide plate 1 A substantially square light diffusing plate 6 arranged on the side is provided.

It is preferable that the light guide plate 1 is a transparent substrate with good light transmittance. As a material of a transparent substrate, 1 or more types of thermoplastic resins, such as a methacryl resin, a polycarbonate resin, a polystyrene resin, a polyolefin resin, etc. are mentioned, for example. Moreover, you may use the laminated body of these resin as a transparent substrate. Especially, methacryl resin is preferable from a viewpoint of transparency, light guide, and workability. As for methacryl resin, it is more preferable that total light transmittance is 90% or more.

It is preferable that the light guide plate 1 is a substantially rectangular flat plate. The substantially rectangular shape here means the shape which consists of four sides, such as a square, a rectangle, and a rhombus, but the vertex part may be rounded. The thickness of the light guide plate 1 is usually about 1 to 10 mm, and preferably 3 to 8 mm. On the other hand, it is preferable that the thickness of the light guide plate 1 is thicker than the thickness of the light source 2A (or the whole unit) from the point that the light exiting from the light source 2A to be described later is well received.

As the light source 2A, as shown in FIG. 2, it may be arranged on one side end surface side of the light guide plate 1, and as shown in FIGS. 1 and 3, it may be arranged on two side end surface sides facing each other. do. As a light source, a fluorescent lamp, a cold cathode tube, LED, etc. are mentioned. When a fluorescent lamp or a cold cathode tube is used, it is usually arrange | positioned substantially parallel to the longitudinal direction in the light guide plate side cross section. In the case of using an LED, a plurality of LEDs are usually disposed substantially parallel to the longitudinal direction in the light guide plate side cross-section. In particular, since LEDs are small in size, they are useful in reducing illumination. Although there is no restriction | limiting in particular about the color of LED, White is preferable when using indoors, such as a house, an office, a commercial facility, a gas station, and a vehicle. Moreover, as a white LED, the LED which emits white light by the combination of a blue LED and a yellow fluorescent substance, and the LED which emits white light by combining each LED of red, blue, and green are mentioned.

As the reflecting film 3 arrange | positioned at the reflecting surface side of the light-guide plate 1, the low foaming film made from white polyester, the film which deposited the metal with high reflectance on glass or a plastic film, etc. are mentioned, for example. have. The thickness of the reflective film 3 is about 50-400 micrometers normally.

The light diffusion plate 6 is disposed on the light exit surface side of the light guide plate 1. As such a light-diffusion plate 6, the conventionally well-known light-diffusion plate with which light-diffusion performance was given to the transparent substrate can be employ | adopted. As a material of such a transparent substrate, 1 or more types of thermoplastic resins, such as a methacryl resin, a polycarbonate resin, a polystyrene resin, a polyolefin resin, etc. are mentioned like a light guide plate mentioned above. Moreover, you may use the laminated body of these resin as a light-diffusion plate. Especially, methacryl resin is preferable from a viewpoint of moldability and surface hardness. As a method for imparting light diffusion performance to the transparent substrate, a conventionally known method can be adopted, and for example, a method of forming an uneven shape on the surface of the transparent substrate, or a refractive index different from that of the transparent substrate in the transparent substrate. The method etc. which contain 1 or more types of light diffusing agents are mentioned. Examples of the light diffusing agent include organic fine particles such as acrylic crosslinked bis and MS crosslinked bis, and inorganic fine particles such as silica, titanium oxide and barium sulfate. Especially, the said organic type microparticles | fine-particles are preferable. It is preferable that haze value is 80 to 100%, and the light-diffusion plate 6 is 35 to 80% of a total light transmittance.

It is preferable that the light-diffusion plate 6 is a substantially rectangular flat plate similarly to the light guide plate 1 mentioned above. The thickness is about 0.1-5 mm normally, Preferably it is 0.5-4 mm.

The edge light type lighting device of the present invention having the above-mentioned members faces the luminance A ₁ near any one side of the light diffusion plate 6 and the one side on the outer surface of the light diffusion plate 6. The luminance A _{2 in the} vicinity of one side and the luminance B in the vicinity of the line drawn at equidistant distances from these two opposite sides satisfy the following formulas (1) and (2).

B

3.0 × A₁ Formula (l): 1.2 × A ₁

B

3.0 × A ₁

B

3.0 × A₂ Equation (2): 1.2 × A ₂

B

3.0 × A ₂

As for the edge light type lighting device which satisfy | fills said Formula (1) and Formula (2), the brightness | luminance of the vicinity of the center part of the said lighting apparatus becomes high substantially compared with the brightness | luminance of the vicinity of the both ends in the said lighting apparatus. (1.2 times or more and 3.0 times or less) means a lighting device. That is, it means that considerable unevenness has arisen in the brightness | luminance of the vicinity of the both ends and the center part of the said lighting apparatus. When the lighting device satisfies such property values, that is, has an appropriate luminance non-uniformity, and the lighting device is installed, for example, on the ceiling of an indoor, an effect that the indoor person can feel good brightness is exerted. In addition, since the illuminance at the inner periphery of the indoor to which light is irradiated is appropriately maintained, sufficient illuminance can be obtained just under the normal direction of the illuminating device, and therefore it is particularly preferable as the illuminating device indoors.

An edge light type lighting device in which the luminance A ₁ , the luminance A ₂ and the luminance B satisfy the following formulas (3) and (4) is more preferable.

B

2.5 × A₁ Equation (3): 1.4 × A ₁

B

2.5 × A ₁

B

2.5 × A₂ Equation (4): 1.4 × A ₂

B

2.5 × A ₂

When the luminance B is less than 1.2 times with respect to the luminance A ₁ or the luminance A ₂ , the brightness felt by the person viewing the lighting apparatus and the illuminance just under the normal direction of the lighting apparatus may not be sufficient. On the other hand, when the luminance B is, in the case of more than 3.0 times the luminance A _1, a brightness A _2, for example, the illuminance at the inner periphery of that the building of using the illumination device in the building is not sufficient There is.

Light emitted from the light source 2A is incident into the light guide plate 1 from the side end surface of the light guide plate 1. And this incident light is diffusely reflected by the diffuse reflection part 10 while repeating reflection in the light guide plate 1, and is then emitted from the light exit surface of the light guide plate 1. In addition, a part of the light in the light guide plate 1 is prevented from being emitted from between the diffuse reflection part 10 or the diffuse reflection part 10, and the reflective film 3 is used to reflect the light and enter the light guide plate 1 again. Arranged (FIGS. 1-3).

The diffuse reflection part 10 is formed in the shape of a dot or stripe which consists of a substantially circular shape, an approximately point shape, an approximately rectangular shape, or the like, and is preferably a dot shape. Moreover, as a formation method of this diffuse reflection part, the method of matting the surface of the light-guide plate 1, the method of performing a specific wedge-shaped process, the method of screen printing or depositing predetermined ink etc. are mentioned, for example. have. Especially, it is preferable to form by screen printing. A conventionally well-known thing can be employ | adopted as the said ink, For example, a volatile-curable ink or ultraviolet curable ink containing microparticles | fine-particles for diffusely reflecting light, such as a titanium oxide microparticle, a silica microparticle, an acrylic bead, a micro hollow particle, etc. Can be mentioned. Screen printing is performed by apply | coating the said ink to a light guide plate in the vicinity of room temperature, and then drying at about room temperature to about 80 degreeC.

It is preferable that the said diffuse reflection part 10 is formed so that the dot density may become high as it moves away from the side end surface side where the light source 2A is arrange | positioned from a viewpoint of illumination intensity. As a method of forming so that a dot density may become high, (1) the pitch (center distance) of a dot is made constant, and the dot area increases as it moves away from the side end surface side where the light source 2A is arrange | positioned, (2) The method of making a dot area constant and shortening the pitch of a dot as it moves away from the side end surface side where the light source 2A is arrange | positioned, etc. are mentioned. In addition, when forming a dot-shaped diffuse reflection part, a dot area is 0.3-2.0 mm <2> normally, Preferably it is 0.4-1.5 mm <2>. The pitch of a dot is 0.5-3.0 mm normally, Preferably it is 1.0-2.0 mm. The density of the dot which occupies per unit area, ie, dot occupancy density, is 10 to 60% normally, Preferably it is 20 to 55%. In addition, these dot-shaped diffuse reflection portions may be arranged in parallel in the longitudinal direction and the transverse direction of the light guide plate 1, or may be arranged to be partially shifted. Further, it is more preferable that the equilateral triangle is arranged so as to draw an equilateral triangle by connecting the center of the dot adjacent to the dot from the center of any one dot.

As described above, the edge light type lighting device of the present invention requires that the luminance B satisfies the above (1) and (2) with respect to the luminance A ₁ and the luminance A ₂ . Such a requirement is provided by appropriately adjusting the formation pattern of the diffuse reflection portion. Specifically, when the above-mentioned dot or stripe diffuse reflection part is formed in the light guide plate 1, and the edge light type illuminating device is actually assembled and evaluated and the above formulas (1) and (2) are not satisfied, Adjust the density to be large or small, and reassemble and evaluate the device again. By repeating such an operation, an edge light type lighting device satisfying the above formulas (1) and (2) is manufactured.

For example, in the case where the diffuse reflection part is formed in a dot shape, the dot density increases as the distance from the side end surface side on which the light source 2A is disposed is formed in a pattern, and the pattern is,

(A) When the luminance B becomes less than 1.2 times the luminance A ₁ or the luminance A ₂ , the dot density in the vicinity of the side cross section side where the light source is arranged is reduced, and the dot density is the highest. Increases dot density,

(B) In the case where the luminance B exceeds 3.0 times the luminance A ₁ or the luminance A ₂ , the dot density in the vicinity of the side cross section side where the light source is arranged is increased, and the dot density is the highest. By reducing the dot density and adjusting the dot density, an edge light type lighting device that satisfies the above formulas (1) and (2) is manufactured.

In this invention, in order to make the light radiate | emitted from the light source 2A favorable to the light guide plate 1, as shown in FIGS. 1-3, the reflective film 3 is extended and arrange | positioned to the vicinity of the light source 2A. It is preferable to further arrange the reflector 4 in the vicinity of the light source 2A. Such a reflector 4 can be arranged in the vicinity of the light source 2A, on the opposite side of the reflective film 3 (FIGS. 1 to 3), and behind the LED light source 2A (in the opposite direction to the light guide plate 1). Can be placed in (not shown). As the reflector 4, the reflector of the same material as the above-mentioned reflective film can be used, for example, and the thickness is about 50-400 micrometers normally.

In addition, as shown in FIG. 2, when the light source 2A is arrange | positioned at one side end surface side of the light guide plate 1, a reflection film is provided in the side end surface side which opposes the side end surface in which the light source 2A is arrange | positioned. It is preferable to attach it. Such a reflective film can use the thing of the same material as the above-mentioned reflective film. Moreover, it is preferable to affix the said reflective film also to the other side end surface in which the light source 2A is not arrange | positioned in the light guide plate 1.

And as shown in FIGS. 1-3, each member, such as the light guide plate 1, the light source 2A, and the reflective film 3, is normally accommodated in the metal frame 5, such as aluminum.

In addition, a prism sheet can be arrange | positioned further outside of the said light-diffusion plate (illustration omitted).

Example

Hereinafter, although the Example and comparative example of this invention are shown, this invention is not limited to these at all. Moreover, about the edge light type lighting apparatus of an Example and a comparative example, it evaluated by the following test method.

(1) luminance measurement

An edge light type lighting device was placed in the center of the ceiling of a box-shaped black thread having a width of 2 m, a depth of 2 m, and a height of 2 m. The reflectance (85 degree reflectance) of the ceiling and the wall was made into 0%. In addition, the power consumption of the edge light type lighting device is 64 W, and the measurement camera is installed at a position 500 mm away from the illumination emission surface in the normal direction of the surface, and the luminance at the following predetermined position It measured using "EyeScales3" by the company.

(A) a light source was from the side of one side of the light diffusion plate is arranged a brightness of the light diffusion plate 20 ㎜ position apart in the longitudinal direction of the A _1.

(B) to the luminance of the one side and the light diffusion plate 1 side from the light diffusion plate 20 ㎜ position apart in the longitudinal direction of the facing in the longitudinal direction of the A _2.

(C) The luminance of each side and equidistant distance (75 mm from each side) described in said (A) and (B) was set to B, respectively.

(2) roughness measurement

An edge light type lighting device was placed in the center of the ceiling of a box-shaped white thread having a width of 3 m, a depth of 3 m, and a height of 2 m. The reflectance (85 degree reflectance) of the ceiling and the wall was made into 30%. In addition, the power consumption of the edge light type illuminating device was 64 W, and the illuminance in the 1100 mm position just below the illumination exit surface was measured using the ANA-F12 illuminometer by the Tokyo photoelectric company.

(3) The brightness that a person feels (called "personality")

When the observer enters the box-shaped white room and visually observes the edge-lit lighting device under evaluation, the observer feels that it is bright enough ◎, when it feels slightly bright ○, when it feels slightly dark △, dark When it felt, it was set as x.

Example 1, Comparative Example 1

The edge light type illuminating device was manufactured using the member shown below.

<Absence of edge light type lighting device>

(Light guide plate)

Methacrylic resin composition ("Sumipex E005 by Sumitomo Chemical Co., Ltd.") shape | molded to thickness 5mm and length 150mm x 1200mm in width was used.

(Ink used for screen printing)

On the surface (reflection surface) of this light guide plate, substantially circular dot shape was formed by screen printing using the following ink.

Volatilization Curable Resin Ink 76.8% by weight

16.4% by weight of acrylic beads

Silica Fine Particles 3.2% by weight

Phosphor 3.6 wt%

(About dot pattern)

The said dot was formed so that the pitch (center distance) might become constant, and that dot area became large as it moved away from the side end surface side in which the light source is arrange | positioned. Moreover, the graph which made the vertical axis the density (dot occupancy density) which occupies per unit area, and made the horizontal axis the distance from the said side end surface side of a light guide plate is shown to FIG. 4 (Example 1) and FIG. 5 (Comparative Example 1). . 6 is a diagram showing the positional relationship between any one dot and the dot adjacent to the dot.

In Example 1, the pitch of the dots is 1.73 mm, the minimum diameter is 0.83 mm, and the maximum diameter is 1.31 mm. In Comparative Example 1, the pitch of the dots is 1.73 mm, the minimum diameter is 1.04 mm, and the maximum diameter is 1.26. It set to mm.

(Light diffusion plate)

The methacryl resin composition ("Sumipex E535" by Sumitomo Chemical Co., Ltd.) shape | molded to thickness 2mm and length 150mm x 1200mm in width was used.

(Light source)

As the light source, 240 white LEDs (0.27 W / piece) manufactured by CREE Corporation were used. Moreover, the said white LED was arrange | positioned so that it might become substantially linear each 120 pieces in two side end surface sides of 5 mm x 1200 mm in a light guide plate.

(Reflective film)

Tore Co., Ltd. "E60" film (180 micrometers in thickness, 150 mm long x 1208 mm) was arrange | positioned at the reflecting surface side of the said light guide plate. And the said "E60" film (180 micrometers in thickness, 5 mm x 150 mm) was also attached to the side end surface side of the light guide plate in which the light source is not arrange | positioned.

(Reflector)

The "E60" film (180 micrometers in thickness, 14mm in length x 1200mm in width) by a Toray Corporation was arrange | positioned as a reflector below the said light source.

Table 1 shows the results of Example 1 and Comparative Example 1.

Luminance A ₁ Luminance A ₂  Luminance B A ₁ / B A ₂ / B Luminance just below the normal direction (lx)  Seal Example 1    1699   1699   2886   1.69   1.69   1290    ◎ Comparative Example 1    2602   2602   2719   1.04   1.04   1280    △

One … Light guide plate
10 ... Diffuse reflection
2A. LED lights
2B. LED array
3…. Reflective film
4 … Reflector
5 ... Aluminum frame
6 ... Light diffusion plate
7 ... Edgelight type lighting device

Claims (6)

A substantially rectangular light guide plate, a light source disposed on at least one side end surface side of the light guide plate, and a reflection surface side opposite to the light exit surface of the light guide plate from which the light emitted from the light source is incident on the side end surface of the light guide plate; An edge light type lighting device comprising: a substantially rectangular reflective film disposed; and a substantially rectangular optical diffuser disposed on the light emitting surface side of the light guide plate, and a diffuse reflection portion for diffusely reflecting light is formed on the reflective surface surface of the light guide plate. ,
On the outer surface of the light diffusion plate, the luminance A ₁ near one of the sides of the light diffusion plate, the luminance A ₂ near the one side opposite to the one side, and the two sides opposite to each other are drawn at equidistant distances. An edge light type illuminating device, wherein the luminance B near the line satisfies the following formulas (1) and (2).
Equation (1): 1.2 × A ₁

B

3.0 × A ₁
Equation (2): 1.2 × A ₂

B

3.0 × A ₂ The method of claim 1,
1 side with the said light-diffusion plate, The illuminating device substantially parallel to the longitudinal direction in the light-guide plate side cross section in which the light source is arrange | positioned. The method of claim 2,
An illuminating device in which a light source is arrange | positioned at two side end surface sides facing a light guide plate. The method of claim 3, wherein
The diffuse reflection part is formed in a dot shape, and is formed in a pattern in which the dot density increases as the distance from the side end surface side on which the light source is arranged is increased, and the pattern is
(A) When the luminance B becomes less than 1.2 times the luminance A ₁ or the luminance A ₂ , the dot density in the vicinity of the side cross section side where the light source is arranged is reduced, and the dot density is the highest. Increases dot density,
(B) In the case where the luminance B exceeds 3.0 times the luminance A ₁ or the luminance A ₂ , the dot density in the vicinity of the side cross section side where the light source is arranged is increased, and the dot density is the highest. Illumination apparatus determined to satisfy said formula (1) and (2) by reducing dot density. The method according to any one of claims 1 to 4,
Furthermore, the illuminating device in which the reflector for injecting the light radiate | emitted from the said light source into the said light guide plate is arrange | positioned in the vicinity of the said light source. 6. The method according to any one of claims 1 to 5,
Lighting device wherein the light source is an LED light source.

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