JP2001023423A - Flat light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat light source unit of a edge light system using a point light source such as LED's equipped with an improved uniformity in the brightness of the illuminating light. SOLUTION: A flat light source unit 10 embodied on the edge light system is equipped with a photo-guide member 1 formed in a plate shape from a photo- transmissive material, having a first main surface to serve as a light emitting surface 1b and furnished with a light diffusing means on a second main surface 1a confronting the first main surface, and a light source 2 positioned close to the side face of the photo-guide member 1, wherein the photo-guide member 1 is furnished with a blind hole having an effect to distribute to the left and right the incident light from the source 2 and admit partial passage of the light and also with a reflection part 6 on the side face 1d, and thereby the light from the light source 2 is widened uniformly by means of optical path conversion so as to generate a condition free of directionality and is radiated onto the oversurface and undersurface of the photo-guide member 1, and it is made practicable that a flat light flux having uniform brightness is emitted from the light emitting surface 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar light source unit of a display device having a backlight mechanism for illuminating a transmissive or transflective panel from the back.

[0002]

2. Description of the Related Art In recent years, book-type word processors and computers, portable telephones, small-sized portable telephones such as portable TVs, and the like.
2. Description of the Related Art As a display device of a thin information device, a liquid crystal display device having a thin and easy-to-see backlight mechanism is used. As such a backlight mechanism, a planar light source that irradiates the liquid crystal panel from behind to the entire surface is used. As the planar light source, a fluorescent lamp, which is a linear light emitting source, and a luminous flux of the liquid crystal panel are used. In general, a light guide plate that converts light into a planar light beam to be irradiated has been used.
Plural LEDs (light emitting diodes) instead of fluorescent lamps as linear light sources for the purpose of further thinning and longer life
Are arranged in a line.

FIGS. 9 and 10 show an LED (light emitting diode) as an example of such a conventional backlight mechanism.
FIG. 10 is a diagram showing a planar light source unit for an edge light type panel having an array light source, FIG. 9 is a perspective view, and FIG. 10 is a cross-sectional view thereof. 9 and 10, reference numeral 110 denotes a planar light source unit, which includes a light guide member 101 and a plurality of LEDs 102 arranged linearly as a light source. The light guide member 101 has a plate-like and substantially rectangular parallelepiped shape made of a light-transmitting member such as a transparent plastic material. One of the wide surfaces is a light-emitting surface 101b, and a surface facing the light-emitting surface 101b has As means for reflecting light from the light source toward the opposing light emitting surface, a light diffusing surface 101a such as a plurality of minute grains or a plurality of dot dots is formed on the surface.

Further, a reflection plate 103 such as a white sheet is provided near the light diffusion surface 101a. The light emitted from the LED 102 enters the light guide 101, and most of the light undergoes total reflection once on the upper surface (light emitting surface) 101b, total reflection on the lower surface, or scattering once by the light diffusing surface 101a such as a grain or a dot. Alternatively, the light is emitted from the upper surface to the outside after performing a plurality of times. At this time, a part of the light is transmitted through the lower surface and enters the reflection plate 103. However, the light is reflected here and enters the light guide member 101 again, and is emitted from the upper surface to the outside directly or after being reflected. The light emitted to the outside passes through the liquid crystal panel 107 to illuminate. In order to ensure the uniformity of the luminance in the surface to be illuminated, the roughness of the grain in the lower surface is adjusted, and the shape and density of dot-like dots are changed depending on the location.

[0005]

However, the above-mentioned planar light source unit has the following problems. In other words, it is possible to adjust the degree of uniformity of the luminance in the plane of the illumination to some extent by adjusting the roughness of the grain or changing the shape and density of the dot dots depending on the location, but this also has a limit. The light emitted from one side of the side surface of the light guide member needs to be a linear light source having a certain degree of uniformity. In order to realize this, a linear light source is formed by arranging a plurality of point light sources such as LEDs. I have to make it approximate to That is, if there is only one LED, because of its directivity,
Since the intensity of light emission greatly changes depending on the direction, the influence appears as a non-uniform distribution of the luminance of the illumination light, making uniform illumination impossible. Therefore, many LEDs
Is required, and there is a problem that the cost is increased and the current consumption is increased.

An object of the present invention is to improve the above-mentioned problems in the prior art. The present invention solves the above-described problem, and enables one or a small number of LEDs close to a point light source to be used as a light source in an edge light type planar light source unit to emit a uniform planar light flux. The purpose is to do. This allows
It is possible to provide an inexpensive planar light source unit in which the illumination light is uniform and the cost and power consumption of the light source are reduced.

[0007]

In order to solve the above-mentioned problems, as a first means, the present invention has a plate-like shape made of a light-transmitting material, and has a first main surface as a light-emitting surface. In an edge light type planar light source unit having a light guide member provided with light diffusing means on a second main surface opposite to the first main surface, and a light source arranged close to a side surface of the light guide member. The light guide member is provided with one or more blind holes that have a function of refracting and reflecting light emitted from the light source in the thickness direction.

According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the first aspect, reflecting portions are provided on both sides of a portion facing the light source on a side surface of the light guide member. It is characterized by.

According to a third aspect of the present invention, there is provided the light emitting device according to the second aspect, wherein the reflecting portion comprises a substantially arc-shaped groove substantially parallel to a thickness direction of the light guide member. It is characterized by the following.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problem, in the third aspect, the substantially arc-shaped groove of the reflecting portion is densely arranged as the distance from the light source increases. It is characterized by.

According to a fifth aspect of the present invention, there is provided the light guide member according to any one of the second to fourth means, wherein the light guide member is provided on both sides of a portion facing the light source. An angle formed between the side surfaces is smaller than 180 °, and a substantially triangular protruding portion is formed on a part of the light guide member by these side surfaces.

According to a sixth aspect of the present invention, in order to solve the above-mentioned problems, in any one of the first to fifth means, the blind hole provided in the light guide member is the first means.
Has an opening in the main surface thereof, does not have an opening in the second main surface, has a planar shape that is substantially an inverted triangle when viewed from the light source, and the light source is a vertex of the inverted triangle. Characterized in that it is arranged at a position opposite to.

According to a seventh aspect of the present invention, in order to solve the above problem, in the sixth aspect, the plane shape of the blind hole provided in the light guide member is symmetrical as viewed from the light source. The light source has a substantially triangular shape, and the light source is disposed at a position facing a vertex formed by two equal sides of the triangle.

According to an eighth aspect of the present invention, to solve the above-mentioned problem, the present invention is characterized in that, in the sixth or the seventh means, two sides of the substantially inverted triangular blind hole facing the light source are free. It is characterized by being formed by a part of the object surface.

According to a ninth aspect of the present invention, there is provided the light guide member according to any one of the first to eighth means, wherein the depth of the blind hole provided in the light guide member is the same as that of the first to eighth aspects. It is characterized in that it is set to be deeper according to the distance from the light source.

According to a tenth aspect of the present invention, there is provided a light-emitting device according to any one of the first to ninth aspects, wherein the light is provided on a second main surface of the light-guiding member. The diffusion means is a grain or a depression of a plurality of dot dots.

According to an eleventh aspect of the present invention, there is provided the light guide member according to any one of the first to tenth aspects, wherein at least a part of the second main surface of the light guide member is provided. Is characterized in that the light guide member is inclined with respect to the first main surface, and the thickness of the light guide member decreases as the distance from the light source increases.

According to a twelfth aspect of the present invention, in order to solve the above-mentioned problems, in any one of the first to eleventh means, the light source is an LED.

As a thirteenth means for solving the above-mentioned problems, the present invention is characterized in that in the twelfth means, the LED is a white LED.

According to a fourteenth aspect of the present invention, there is provided the light emitting device according to the twelfth aspect, wherein the LED comprises a plurality of LEDs of different colors arranged vertically in a thickness direction of the light guide member. It is characterized by being.

According to a fifteenth aspect of the present invention, in order to solve the above-mentioned problem, in the fourteenth aspect, the LEDs are LEDs of three colors of R, G, and B.

As a sixteenth means for solving the above problems, the present invention provides a plate-like shape made of a light-transmitting material, wherein the first main surface is a light-emitting surface, and the first main surface is In an edge light type planar light source unit having a light guide member provided with a light diffusing means on the opposing second main surface and a light source arranged close to a side surface of the light guide member, The light emitted from the light source is refracted and provided with a plurality of blind holes concaved in the thickness direction having a function of reflecting, and opposed to each of the blind holes,
It is characterized in that the light sources are arranged separately.

According to a seventeenth aspect of the present invention, in order to solve the above-mentioned problem, in the first aspect, the planar shape of the light guide member is substantially rectangular, and the light source is provided near the corner. It is characterized by having.

According to an eighteenth aspect of the present invention, in order to solve the above-mentioned problems, the present invention is directed to any one of the first to seventeenth means, wherein the second main surface of the light guide member and / or the light source is provided. A reflective sheet or a reflective member formed by silver deposition or the like is provided so as to face or contact both side surfaces of a portion facing the above.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This embodiment relates to a planar light source unit. 1 is a perspective view showing a configuration of a planar light source unit according to the present embodiment, FIG. 2 is a cross-sectional view thereof, FIG. 1 (a) is a cross-sectional view taken along line AA of FIG. 1, and FIG. It is B sectional drawing. In FIG. 1, reference numeral 10 denotes a planar light source unit, which includes a light guide member 1, an LED 2 serving as a light source, and a reflector 3. The light guide member 1 is provided with a substantially inverted triangular planar blind hole 4 having a function of refracting and reflecting light so as to open on an upper surface which is a light emitting surface 1b described later. The blind hole 4 is provided substantially directly above the LED 2. The shape of the blind hole 4 is such that two sides (surfaces) facing the LED 2 are substantially parabolic surfaces 4a. When light coming out of the focus of the paraboloid 4a hits the paraboloid 4a, it is totally reflected,
The light becomes parallel to the axis of the paraboloid. Therefore, by arranging the LED 2 at the focal point of the paraboloid 4a, the light reflected on the paraboloid 4a can be distributed to the left and right as almost parallel rays.

The shape of the incident portion 5 of the light guide member 1 is a semicircular relief portion, and a reflecting portion 6 formed of a plurality of arc grooves parallel to the thickness direction is formed on the side surface 1d of the protruding portion on both sides thereof. ing. The grooves of the reflecting portion 6 are arranged denser as the distance from the LED of the light source increases. Although the reflecting portion shown in this example is formed of a circular arc groove, a reflecting portion may be formed by forming a rough surface or the like that causes irregular reflection partially or entirely on the side surface.

One of the wide surfaces of the light guide member 1 is
b as a radiation means for irregularly reflecting light from the LED 2 toward the light emitting surface 1b on a surface facing the light emitting surface 1b, and a plurality of minute embosses or depressions of a plurality of dot dots on the surface. The light diffusion surface 1a is formed.
The arrangement of the reflection plate 3 such as a white sheet close to the light diffusion surface 1a is the same as in the prior art. The same effect can be obtained by attaching a silver deposition film or the like to the light diffusion surface 1a instead of the reflection plate 3. Although not shown, if necessary, the light guide member 1 faces or contacts the side surface 1d or the other side surface on which the reflection portion 6 formed of the arc groove is formed, and a reflection sheet, silver deposition, or the like is performed. Reflective member can be provided. In addition to the above-described inverted triangular blind hole 4, a plurality of through holes or blind holes (not shown) are formed at desired positions on the left and right sides, and the direction of light emission can be freely adjusted.
The LED used in the present embodiment may be an LED of any one of R, G, and B, or may be a white LED.

As shown in FIG. 2A, the bottom surface 4 of the blind hole 4
c is parallel to the lower surface 1a of the light guide member 1, and a bypass portion 1c of the light guide member 1 exists below the lower surface 1a. The operation of the planar light source unit having the above configuration will be described.
As shown in FIG. 1, light emitted from the LED 2 enters the light guide member 1, a part of which is reflected by the paraboloid 4a of the blind hole 4 as a first route, and the other part is shown in FIG. As shown in a), as a second route, the user enters the bypass section 1c below the blind hole 4. Further, as shown in FIG. 1, the remaining one passes through a portion other than the parabola 4 a and the bypass portion 1 c below the blind hole 4 as a third route, that is,
It passes through the left and right sides of the blind hole 4 and enters the main light emitting portion of the light guide member 1.

As a first route, the light reflected by the paraboloid 4a is refracted and reflected by the reflecting portion 6 formed by an arc groove as shown in FIG. 1, and the light path is changed so that the point light source becomes a linear light source. As shown in FIG. 2B, the light that has been spread right and left by the conversion is incident on the light emitting surface 1b that is the upper surface of the light guide member 1 or the light diffusing surface 1a that is the lower surface, and is totally reflected on the upper surface. On the lower surface, the light is scattered or reflected by the total reflection, the grain, or the depression of the dot, or the transmitted light is scattered by the lower reflecting plate 3 and emitted from the light exit surface 1b as illumination light. At this time, the brightness of the light incident on the reflection unit 6 tends to decrease as the distance from the LED increases due to the solid angle. However, as described above, the density of the plurality of grooves of the reflecting section 6 is LE
As the distance from D increases, the brightness of the light reflected from the reflector 6 into the light guide member 1 does not decrease even near the left and right ends.

As described above, when a reflecting member such as a reflecting sheet is provided so as to face or contact the side surface on which the reflecting portion 6 is formed, light transmitted from the reflecting portion 6 or these side surfaces is reflected. The light is scattered by the sheet or the like and returned to the inside of the light guide member 1 again, so that the efficiency of the optical path conversion is increased, and finally, the brightness of the illumination light is increased.

As a second route, the light entering the bypass portion 1c is totally reflected by the bottom surface 4c of the blind hole 4, and is totally reflected or textured on the light diffusing surface 1a which is the lower surface of the light guide member 1 facing the light. The scattered reflection or transmitted light due to the depression of the dot-like dot or the like is scattered by the lower reflector 3, and after passing through the bypass portion 1c while repeating these reflection and scattering, light is emitted according to the same principle as described above. Light is emitted from the surface 1b as illumination light. Next, as the third route, blind hole 4
Light entering the main light-emitting portion of the light guide 1 through the left and right of the light guide member 1 is incident on the light emitting surface 1b, which is the upper surface of the light guide member 1, or the light diffusing surface 1a, which is the lower surface. Or scattered reflection due to embossing, depression of dot-like dots, or
The transmitted light is scattered by the lower reflector 3 and is emitted from the light exit surface 1b as illumination light.

As described above, light passing through three types of routes is emitted from the light emitting surface 1b.
Since the light reflected by the first route is distributed to the left and right, the brightness of the light tends to be higher in the left and right portions of the light emitting surface 1b than in the center. Since the third route also passes right and left of the blind hole 4, similarly,
The brightness of light tends to be higher in the left and right portions of the light exit surface 1b than at the center. On the other hand, in the case of the second route passing through the bypass portion 1c, since the light passes mainly through the center, the brightness of the light tends to be higher in the central portion of the light emitting surface 1b than in the left and right portions.

Therefore, by appropriately selecting the ratio of the amount of light along the first and third routes and the amount of light along the second route, the characteristics of the luminance are complemented with each other. The brightness of the emitted light for illumination over the entire light emitting surface 1b can be made uniform or substantially uniform. Such a balance of luminance can be achieved, for example, by appropriately selecting the width of the blind hole 4 in the left-right direction and the ratio of the depth t1 to the thickness t2 of the bypass portion 1c. At this time, changing the roughness of the grain on the lower surface 1a or changing the shape and density of the pits of the dot-like dots depending on the location in order to equalize the luminance of the illumination light has the same effect as in the prior art. What to do. In this way, the illumination light emitted from the light exit surface 1b of the light guide member 1 passes through the liquid crystal panel 7, and illumination without luminance unevenness is performed.

Hereinafter, a modified example of the planar light source unit shown in FIG. 1 will be described as another embodiment of the present invention with reference to the drawings. FIG. 3 is a cross-sectional view showing the configuration of the planar light source unit according to the modification. The symbols of each element shown in FIG. 3 are the same as the symbols of the corresponding elements in FIG. As shown in FIG. 3, the planar light source unit 1 of the present modified example
0, the bottom surface 4a of the blind hole 4 is the lower surface 1 of the light guide member 1.
It is inclined with respect to a, and the depth of the blind hole 4 is set so as to increase as the distance from the LED as the light source increases. The planar shape of the planar light source unit according to this modification is the same as that shown in FIG.

Next, the operation of the planar light source unit according to this modification will be described. Its operation is basically the same as that shown in FIGS. 1 and 2 and described above. Here, of the light that has entered the light guide member 1 from the LED 2, the light that has entered the bypass portion 1c as the second route passes through the bypass portion 1c while repeating reflection and scattering according to the same principle as described above. After that, the light is emitted from the light emitting surface 1b as illumination light while repeating the reflection and scattering between the upper and lower surfaces of the light guide member 1, but in this modified example, the shape of the bypass portion 1c is tapered. The amount of light passing through the bypass unit does not change much even if the angle of the light incident on the bypass unit 1c changes. Therefore, even if the position of the LED 2 is slightly shifted up and down, the amount of light passing through the bypass portion is substantially constant, and the alignment of the LED 2 is excessively strictly adjusted in order to make the luminance of the illumination light as the surface light source uniform. There is no need to perform this, making assembly easier.

Hereinafter, another modified example of the planar light source unit shown in FIG. 1 will be described as another embodiment of the present invention with reference to the drawings. FIG. 4 is a perspective view showing the configuration of the planar light source unit according to this modification, and FIG.
FIG. 5 is a sectional view taken along line CC of FIG. 4. The symbols of the elements in FIGS. 4 and 5 are the same as the symbols of the corresponding elements in FIGS. 1 and 2. As shown in FIGS. 4 and 5, in the planar light source unit 10 of the present modified example, the portion of the lower surface (light diffusion surface) 1 a of the light guide member 1 ahead of the blind hole 4 becomes the upper surface (light emission surface) 1 b. As you move away from the light source, LED2,
The thickness of the light guide member 1 is reduced.

As shown in FIG. 5, in this modified example,
For example, even when the light reflected by the reflector 6 as the light of the first route enters the upper surface 1b in parallel or substantially parallel to the lower surface 1a having the gradient, the upper surface 1a is diffused or the like.
b. Similar effects can be obtained for the light of the second route and the third route shown in FIG. In this way, the overall brightness of the illumination of the planar light source unit can be increased by efficient optical path conversion.

Hereinafter, another embodiment of the present invention will be described with reference to the drawings. This embodiment relates to a planar light source unit for multicolor illumination. FIG. 6 is a sectional view showing the configuration of the planar light source unit according to the present embodiment. As shown in FIG. 6, the cross-sectional shape of the light guide member 1 is as shown in FIG.
Is the same as The planar shape of the light guide member is not shown, but is similar to that of FIG. 1 and is symmetrical. As shown in FIG. 6, the LEDs 2 are R LEDs 2 r and G L arranged in a line in the thickness direction of the light guide member 1.
It is composed of an ED 2g and a B LED 2b.
The planar positions of the LEDs 2r, 2g, and 2b are the same as the positions of the LEDs 2 shown in FIG. In other respects, the symbols for each element shown in FIG. 6 are similar to the symbols for the corresponding elements in FIG.

With respect to these LEDs, since the light guide member 1 is symmetrical, when the LEDs of each color are individually turned on, light that does not pass through the bypass portion 1c below the blind hole 4 is The distribution of the luminance of the illumination light emitted from the light exit surface 1b is symmetrical and uniform. or,
Although the LEDs (2r, 2g, 2b) of each color are shifted up and down, since the shape of the bypass portion 1c is tapered,
According to the principle described above, the ratio of the amount of light passing through the bypass portion to the amount of light passing through other portions hardly depends on the positions above and below the LED, and is substantially constant. Any light from the LED can be emitted from the light exit surface 1b of the light guide member 1 as illumination light having a balance between left, right, and center, uniform luminance, and a uniform multicolor (multicolor) light to the liquid crystal panel 7. ) Lighting becomes possible.

Hereinafter, another embodiment of the present invention will be described with reference to the drawings. The present embodiment relates to a planar light source unit having two independent blind holes having an action of distributing incident light to the left and right and LEDs individually opposed to the respective blind holes. FIG. 7 is a perspective view showing the configuration of the planar light source unit according to the present embodiment. The symbols of the elements shown in FIG. 7 are the same as the symbols of the corresponding elements in FIG. As shown in FIG. 7, the planar light source unit 10 according to the present embodiment has a form in which two planar light source units shown in FIG. 1 are connected in parallel. That is, the right and left halves of the planar light source unit are the same, each having an individual blind hole 4, LED2, etc.
Performs substantially the same operation according to the same principle as the planar light source unit shown in FIG. Thus, the planar light source unit 10 can provide illumination with uniform luminance over a wide area regardless of the location. Here, the light guide member 1 is formed integrally, but may be formed by joining two light guide members shown in FIG. 1 in parallel.

Hereinafter, another embodiment of the present invention will be described with reference to the drawings. The present embodiment relates to a planar light source unit in which an LED is provided to face a corner of a light guide member having a substantially square planar shape. FIG. 7 is a top view showing the configuration of the planar light source unit according to the present embodiment. As shown in FIG. 7, in the present embodiment, the light guide member 1 having a substantially rectangular shape has an incident portion 5 at one corner thereof.
And a blind hole 4 having a paraboloid that is symmetrical with respect to the incident portion 5 is provided inside the hole. On the side surface 1d on both sides of the incident part 5, a reflecting part 6 composed of a plurality of arc grooves parallel to the thickness direction is formed. Here, the sectional shape of the blind hole 4 is the same as that shown in FIG. L close to the entrance 5
ED2 is arranged.

One wide surface of the light guide member 1 is defined as a light emitting surface 1b, and a surface facing the light emitting surface 1b is provided as a radiation means for irregularly reflecting light from the LED 2 toward the light emitting surface 1b. The light diffusing surface 1a is formed of a plurality of minute embosses or depressions of a plurality of dot dots. A reflection plate 3 such as a white sheet is provided near the light diffusion surface 1a.

The light emitted from the LED 2 enters the light guide member 1 from the incident portion 5, and by the action of the blind hole 4 and the reflecting portion 6, according to a principle basically similar to that of the planar light source unit shown in FIG.
The point light source is converted directly or through a conversion to a linear light source, and finally the light path is converted to a planar light source. Illumination with uniform brightness from the light emitting surface 1b which is a main part of the upper surface of the light guide member 1 It is emitted as light.

[0044]

As described above, according to the present invention, one or a small number of point light sources such as LEDs are used as light sources in a surface light source unit of an edge light system, and incident light is directed to a light guide member. The light from the light source is evenly spread by efficient optical path conversion by providing a blind hole that has the function of passing a part of the light, and the light is guided from a state without directivity like a linear light source. The light is emitted to the upper and lower surfaces of the optical member, and a planar light beam having uniform luminance can be emitted from the emission surface. This makes it possible to provide an inexpensive planar light source unit in which illumination light is uniform and the cost and power consumption of the light source are reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a planar light source unit according to an embodiment of the present invention.

FIG. 2 is a sectional view of the planar light source unit shown in FIG.

FIG. 3 is a sectional view showing a modification of the planar light source unit shown in FIG.

FIG. 4 is a perspective view showing another modification of the planar light source unit shown in FIG. 1;

FIG. 5 is a sectional view taken along line CC of FIG. 4;

FIG. 6 is a cross-sectional view showing a configuration of a planar light source unit according to another embodiment of the present invention.

FIG. 7 is a perspective view showing a configuration of a planar light source unit according to another embodiment of the present invention.

FIG. 8 is a perspective view showing a configuration of a planar light source unit according to another embodiment of the present invention.

FIG. 9 is a perspective view showing a configuration of a conventional planar light source unit.

FIG. 10 is a sectional view of the planar light source unit shown in FIG. 9;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light guide member 1 a light diffusing surface 1 b light emitting surface 1 c bypass portion 1 d side surface 2 LED 3 reflector 4 blind hole 4 a parabolic surface 5 incident portion 6 reflector 7 liquid crystal panel 10 planar light source unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // F21Y 101: 02 F term (Reference) 2H038 AA52 AA55 BA06 2H091 FA14Z FA16Z FA23Z FA31Z FA45Z FB08 FC02 LA12 LA18

Claims (18)

[Claims] A first plate formed of a light-transmitting material;
A light guide member provided with a light diffusing means on a second main surface opposite to the first main surface, and a light source disposed close to a side surface of the light guide member. In the edge light type planar light source unit, the light guide member is provided with at least one blind hole recessed in a thickness direction having a function of refracting and reflecting light emitted from the light source. unit. 2. The planar light source unit according to claim 1, wherein reflection portions are provided on both sides of a portion of the side surface of the light guide member facing the light source. 3. The planar light source unit according to claim 2, wherein the reflecting portion comprises a substantially arc-shaped groove substantially parallel to a thickness direction of the light guide member. 4. The planar light source unit according to claim 3, wherein the substantially arc-shaped grooves of the reflecting portion are arranged denser as the distance from the light source increases. 5. An angle formed between both side surfaces of a portion of the light guide member facing the light source is smaller than 180 °.
The planar light source unit according to any one of claims 2 to 4, wherein a substantially triangular protruding portion is formed in a part of the light guide member by these side surfaces. 6. The blind hole provided in the light guide member has an opening in the first main surface, and has no opening in the second main surface.
6. The light source according to claim 1, wherein the planar shape is a substantially inverted triangle when viewed from the light source, and the light source is disposed at a position facing a vertex of the inverted triangle. The planar light source unit as described in the above. 7. A plane shape of a blind hole provided in the light guide member is a substantially triangular shape which is bilaterally symmetric when viewed from the light source, and the light source is located at a position facing a vertex formed by two equal sides of the triangle. The planar light source unit according to claim 6, wherein the planar light source unit is arranged. 8. The planar light source according to claim 6, wherein two sides of the substantially inverted triangular blind hole facing the light source are formed by a part of a paraboloid. unit. 9. The light guide member according to claim 1, wherein a depth of the blind hole provided in the light guide member is set to be deeper according to a distance from the light source. The planar light source unit as described in the above. 10. The light diffusing means provided on the second main surface of the light guide member is a grain or a depression of a plurality of dot-like dots. The planar light source unit as described in the above. 11. The light guide member according to claim 1, wherein at least a part of the second main surface of the light guide member is inclined with respect to the first main surface, and the thickness of the light guide member decreases as the distance from the light source increases. The planar light source unit according to any one of claims 1 to 10. 12. The planar light source unit according to claim 1, wherein the light source is an LED. 13. The planar light source unit according to claim 12, wherein the LED is a white LED. 14. The planar light source unit according to claim 12, wherein the LEDs are a plurality of LEDs of different colors arranged vertically in a thickness direction of the light guide member. 15. The LED is an LE of three colors of R, G and B.
The planar light source unit according to claim 14, wherein D is D. 16. A light guide having a plate-like shape made of a light-transmitting material, a first main surface serving as a light-emitting surface, and a light diffusing means provided on a second main surface facing the first main surface. In a planar light source unit of an edge light type having a member and a light source arranged in close proximity to a side surface of the light guide member, in the thickness direction having a function of refracting and reflecting light emitted from the light source to the light guide member. A planar light source unit, wherein a plurality of concave blind holes are provided, and each of the light sources is disposed separately from each of the blind holes. 17. The planar light source unit according to claim 1, wherein the light guide member has a substantially square planar shape, and the light source is provided near a corner thereof. 18. A light-reflecting sheet or a light-reflective member made of silver or the like is provided so as to face or contact the second main surface of the light guide member and / or the side surface on both sides of the portion facing the light source. A planar light source unit according to any one of claims 1 to 17.