JP5492637B2 - Surface emitting device - Google Patents

Description

  The present invention relates to a surface light-emitting device that can be used for illumination or the like as a planar light source.

As a conventional illumination light source, a point light source such as a light emitting diode (LED) or a linear light source such as a cold cathode tube is used. As a method of configuring a planar light source using these point-like or linear light sources, a scattering sheet or a diffusion plate is arranged on the light source to diffuse light, or the light source is connected to the end face of the light guide plate. And a method of emitting light from the surface of the light guide plate.
In order to emit light more uniformly from the surface of the light guide plate, the unevenness that changes the concentration distribution of light diffusion inside the light guide plate or scatters light toward the exit surface according to the distance from the light source, etc. A more uniform luminance distribution can be obtained by changing the depth, shape, density, etc. of the part (see, for example, Patent Document 1).

JP 2007-109554 A

  However, in the case of a method of diffusing light by arranging a scattering sheet or a diffusion plate, there is a problem that the directivity of outgoing light is low. In addition, when light is reflected toward the exit surface by the uneven portion of the light guide plate, there is light that is transmitted through the light guide plate to the opposite end surface without being reflected by any uneven portion, and is incident on the light guide plate. There is a problem that the utilization efficiency (the rate of emission from the emission surface) decreases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface light-emitting device that uses a light guide plate and has high light utilization efficiency and is capable of emitting light with high uniformity in a planar shape.

In order to solve the above-mentioned problems, the present invention comprises a light guide plate having one side as an incident surface and the other side as an output surface, and a light source that makes light incident on the incident surface of the light guide plate. Comprises a first reflecting portion located on the incident surface side and a second reflecting portion located on the exit surface side, and the entrance surface and the exit surface are planes parallel to each other , The reflectors are provided at predetermined intervals along a direction parallel to the incident surface such that the distance from the surface including the incident surface increases with distance from the light source along the direction parallel to the incident surface. A plurality of first reflecting surfaces each having a shape in which the distance from the surface including the incident surface increases as the distance from the light source increases, and the plurality of first reflecting surfaces in the first reflecting portion are the light guide plate It has become the interface between the low refractive index portion made of a cavity formed therein, the second Morphism unit includes a second reflecting surface having a shape where the distance between the plane including the incident surface further away from the light source along a direction parallel to the incident surface increases continuously, the second reflective The second reflection surface in the portion is an interface with the low refractive index portion formed of a cavity provided inside the light guide plate, and the light guide plate is between the incident surface and the first reflection portion. A first portion located; a second portion located between the first reflecting portion and the second reflecting portion; and a third portion located between the second reflecting portion and the exit surface. It is divided into three parts, the first part and the second part are aligned via a plane or conical split surface, and the second part and the third part are flat or It provides a surface emitting device characterized that you have aligned through the splitting surface of the conical surface.

In the present invention, the plurality of first reflecting surfaces in the first reflecting section may be one or more selected from a flat surface, a convex surface, a concave surface, or a textured shape.
The light guide plate may be made of a material transparent to the light of the light source.
It can also be set as the structure provided with the layer which diffuses light on the output surface of the said light-guide plate.
The outer side surface of the light guide plate is polygonal, the first reflecting section and the second reflecting portion may be configured that have similar shapes to suit the outer shape of the light guide plate.
The outer shape of the side surface of the light guide plate may be a quadrangular shape .
The outer shape of the side surface of the light guide plate may be a semicircular shape or a sector shape .
A configuration may also be adopted in which a reflective film is provided on each of the plurality of first reflective surfaces in the first reflective portion .

  According to the present invention, the light incident on the light guide plate from the light source through the incident surface is reflected mainly by the second reflecting surface in the second reflecting portion in the direction away from the light source along the incident surface, The plurality of first reflection surfaces in the first reflection part can be mainly reflected toward the emission surface. Since the plurality of first reflecting surfaces in the first reflecting portion are provided at predetermined intervals, the light is branched and emitted for each of the plurality of first reflecting surfaces, and is emitted from a wide range of the exit surface of the light guide plate. can do. Thereby, it is possible to emit light with high uniformity in a planar shape.

It is (a) top view and (b) sectional view showing the surface light-emitting device concerning the 1st example of the present invention. It is drawing explaining the light emission state of the surface light-emitting device shown in FIG. 1, The mode of main reflection is shown on the left side of a figure, and the mode of main output is shown on the right side of a figure. It is a perspective view which shows the outline external appearance of the surface emitting device shown in FIG. It is a fragmentary sectional view which shows the modification of the surface emitting device of this invention. It is drawing explaining the shape of a reflective surface, and shows (a) plane, (b) convex surface, (c) concave surface, and (d) embossed shape, respectively. It is a fragmentary sectional view which shows the modification of the surface emitting device of this invention. It is sectional drawing which shows an example of the surface light-emitting device of this invention which provided the light-diffusion layer in the output surface. It is sectional drawing which shows an example of the surface light-emitting device of this invention which can be divided | segmented. It is a perspective view which shows an example of the surface light-emitting device whose external shape of the side surface of a light-guide plate is square shape. It is a top view which shows an example of the surface light-emitting device whose external shape of the side surface of a light-guide plate is square shape. It is a top view which shows an example of the surface light-emitting device whose external shape of the side surface of a light-guide plate is semicircle shape. It is a top view which shows an example of the surface light-emitting device whose external shape of the side surface of a light-guide plate is a 90 degree fan shape. It is (a) top view and (b) sectional drawing which show the surface-emitting device which concerns on a 2nd form example as a reference example . It is drawing explaining the light emission state of the surface light-emitting device shown in FIG. 13, The mode of main reflection is shown on the left side of a figure, and the mode of main output is shown on the right side of a figure.

The present invention will be described below based on preferred embodiments with reference to the drawings.
1 to 3 show a surface light emitting device according to a first embodiment of the present invention. The schematic configuration of the surface light emitting device 10 includes a light guide plate 4 having one side surface as an incident surface 4a and the other side surface as an output surface 4b, and a light source 3 that makes light incident on the incident surface 4a of the light guide plate 4. .
In the case of this embodiment, the light guide plate 4 has a disk shape in which the incident surface 4a and the output surface 4b are parallel planes, and the light source 3 is connected to the approximate center of the incident surface 4a. The cross-sectional view of FIG. 1B shows a cross section along an arbitrary radial direction of the light guide plate 4 having a disc shape, and has a structure of a rotator that is symmetric about the central axis.

  The material constituting the light guide plate 4 is not particularly limited as long as the light from the light source 3 can be sufficiently transmitted. For example, an organic material such as acrylic resin or polycarbonate resin, multi-component glass, quartz glass, or the like can be used. A material transparent to the light of the light source 3 such as an inorganic material is suitable. The color of the light guide plate may be colorless and transparent, or may have a predetermined color.

  Although it does not specifically limit as the light source 3, LED (light emitting diode), a light bulb, various lamps, etc. are mentioned. Moreover, it is also possible to use LED of variable colors such as RGB (Red-Green-Blue). In this case, the luminescent color changes with time, and it becomes possible to obtain a dynamic expression with an arbitrary color, which is preferable because the variety of expression is increased.

Inside the light guide plate 4, a first low refractive index portion 6 is formed on the incident surface 4 a side, and a second low refractive index portion 7 is formed on the output surface 4 b side, and between these low refractive index portions 6, 7. Has a high refractive index portion 5 made of a material having a higher refractive index than these low refractive index portions 6 and 7. Although the high refractive index part 5 is not specifically limited, it can be comprised from said material which comprises the light-guide plate 4. FIG. Further, the low refractive index portions 6 and 7 may be hollow. The cavity may be filled with a fluid such as air, or may be communicated with outside air through a gap (not shown). The difference in refractive index between the high refractive index portion 5 and the low refractive index portions 6 and 7 is a total reflection condition expressed by sin θ _c = n ₂ / n ₁ (where θ _c is a critical angle, and n ₁ is a high refractive index. In consideration of the refractive index of the part, n ₂ is the refractive index of the low refractive index part, and n ₁ > n ₂ ), it is suitable for the first reflecting part 1 and the second reflecting part 2 formed at the interface. It is preferable to set so that the rate can be obtained.

  As shown in FIG. 1B, the first reflecting portion 1 is provided between the high refractive index portion 5 and the first low refractive index portion 6. The first reflecting portion 1 is separated from the light source 3 along the direction parallel to the incident surface 4a (the left-right direction in FIG. 1B), and the distance from the surface including the incident surface 4a (the direction perpendicular to the incident surface 4a). The plurality of first reflecting surfaces 1a, 1b, 1c, 1d, and 1e provided at predetermined intervals so as to increase the distance (the vertical distance in FIG. 1B). 1a, 1b, 1c, 1d, 1e. The plurality of first reflecting surfaces 1a, 1b, 1c, 1d, and 1e have shapes in which the distance from the surface including the incident surface 4a increases as the distance from the light source 3 increases along the direction parallel to the incident surface 4a. Have each.

In the example shown in FIG. 1, the number of the plurality of first reflecting surfaces in the first reflecting unit 1 is five concentrically, but is not particularly limited. If there are two or more light sources 3, the number of first reflection surfaces can be set to a desired number.
The “distance from the surface including the incident surface” refers to the distance from the surface including the incident surface 4a to the reflecting portion (if the incident surface 4a is a sufficiently wide plane, the distance from the incident surface 4a to the reflecting portion). Is equal to the distance) in a direction perpendicular to the incident surface 4a. When the incident surface 4a is a curved surface, a plane in contact with the vicinity of the incident surface 4a facing the light source 3 can be used as a reference.

These first reflecting surfaces 1a, 1b, 1c, 1d, and 1e are arranged at intervals from each other along a direction parallel to the incident surface 4a. As shown in FIG. 1A, the first reflecting surfaces 1a, 1b, 1c, 1d, and 1e are formed concentrically around the installation position of the light source 3 in a plan view perpendicular to the incident surface. . In addition, the space | interval of several 1st reflective surfaces in a 1st reflection part can be set suitably, and does not need to be equal intervals.
In the case of this embodiment, the plurality of first reflection surfaces 1 a, 1 b, 1 c, 1 d, and 1 e in the first reflection unit 1 are interfaces with the low refractive index portion 6 provided inside the light guide plate 4. In particular, a desired reflectance can be obtained without providing a separate reflective film.

In the case of the first reflecting portion 1 shown in FIG. 2, a plurality of first reflecting surfaces 1a, 1b, 1c, 1d, and 1e and the surfaces 11a, 11b, 11c, and 11d between them are connected to each other in a step-like cross section. Have It is only necessary that at least the first reflecting surfaces 1a, 1b, 1c, 1d, and 1e of the first reflecting portion 1 can reflect light.
The surfaces 11a, 11b, 11c, and 11d between the first reflecting surfaces are parallel to the incident surface 4a in the example illustrated in FIG. 1, but as illustrated in FIG. 4, the surfaces 11a, 11b, 11c, and 11d are parallel to the surface 12 parallel to the incident surface 4a. May be inclined, curved, bent or the like.
From the viewpoint of suppressing the thickness of the light guide plate 4, it is preferable that the surfaces 11a, 11b, 11c, and 11d between the first reflecting surfaces are parallel to the incident surface 4a, as shown in FIG.

In addition, the second reflecting portion 2 is provided between the high refractive index portion 5 and the second low refractive index portion 7. The second reflecting portion 2 includes a second reflecting surface 2a having a shape in which the distance from the surface including the incident surface 4a continuously increases as the distance from the light source 3 increases in the direction parallel to the incident surface 4a.
In the case of this embodiment, the second reflecting surface 2a of the second reflecting portion 2 is continuous from the position facing the light source 3 to the outer peripheral edge of the second low refractive index portion 7 with a cross-section bent or curved. It is a single reflective surface.

Note that it is not an essential matter of the present invention that the entire second reflecting portion 2 is the second reflecting surface 2a, and (i) a portion that is not a reflecting surface, or (ii) a light reflecting surface 3 that is a reflecting surface. The location where the distance from the surface including the incident surface 4a does not increase (constant or decrease) in the direction away from the second reflecting portion 2 is locally present within the range of the second reflecting portion 2, whereby the second reflecting portion. 2 may include a plurality of second reflecting surfaces.
In the case of this embodiment, the second reflecting surface 2a of the second reflecting portion 2 is an interface with the low refractive index portion 7 provided inside the light guide plate 4, and no special reflecting film is particularly provided. However, a desired reflectance can be obtained.

  The surface light emitting device 10 according to the present embodiment is configured such that the first reflecting portion 1 located on the incident surface 4a side and the second reflecting portion 2 located on the emitting surface 4b side have the above-described shape, so that the light guide plate 4 is reflected and scattered mainly as shown in FIG. 2 and is emitted from the emission surface 4b. Since the internal structure of the light guide plate 4 is symmetrical, the main reflection state is shown on the left side of FIG. 2, and the main emission state is shown on the right side of FIG.

  Usually, the incident light L incident on the light guide plate 4 from the light source 3 is a beam having a predetermined range of divergence angles and light power distribution. Of the second reflecting surface 2a of the second reflecting portion 2, the vicinity of the light source 3 is conical (conical in this embodiment), and most of the light L is reflected (preferably totally reflected). The light is reflected in the direction away from the light source 3 along the incident surface 4a. The tip of the second reflecting portion 2 facing the light source 3 may be a flat surface parallel to the incident surface 4a or a rounded curved surface such as a spherical surface.

  As shown on the left side of FIG. 2, the light L incident on the light guide plate 4 from the light source 3 through the incident surface 4 a is mainly along the incident surface 4 a by the second reflecting surface 2 a in the second reflecting portion 2. Reflected in a direction away from the light source 3. The shape of the second reflecting surface 2a in the second reflecting portion 2 is preferably designed so that light is almost totally reflected according to the position and angle of incidence from the light source 3 to the second reflecting portion 2. In the vicinity of the center of the light guide plate 4, the interface between the second low-refractive index portion 7 and the high-refractive index portion 5 is substantially parallel to the incident surface 4a, and is output from the vicinity of the center of the output surface 4b without being reflected. There is also a light L0 that plays.

  When the light reflected by the second reflecting surface 2a in the second reflecting portion 2 is further incident on the plurality of first reflecting surfaces 1a, 1b, 1c, 1d, and 1e in the first reflecting portion 1, mainly, Reflected toward the exit surface 4b. As a result, as shown on the right side of FIG. 2, the light L1, L2, L3, L4, and L5 reflected by the first reflecting surfaces 1a, 1b, 1c, 1d, and 1e are different from each other in the radial direction. Exit. Although not shown in FIG. 2 for the sake of brevity, outgoing lights L1, L2, L3, L4, and L5 obtained by reflection on the first reflecting surfaces 1a, 1b, 1c, 1d, and 1e are shown on the left side of FIG. Also occurs. Further, there may be light that is repeatedly reflected between the first reflecting portion 1 and the second reflecting portion 2.

  As a result, the incident light L from the light source 3 can be branched into a plurality of outgoing lights L0, L1, L2, L3, L4, and L5 and emitted from a wide range of the outgoing surface 4b of the light guide plate 4. High planar light emission is possible. Furthermore, although not shown in FIG. 2, light that is scattered or refracted without being regularly reflected by the first reflecting portion 1 or the second reflecting portion 2, light that is reflected at the external interface of the light guide plate 4, etc. Therefore, there are various positions and directions in which light is emitted from the emission surface 4b.

When the outgoing lights L0, L1, L2, L3, L4, and L5 are transmitted through the second reflecting portion 2, and when passing through the surface 8b side of the second low refractive index portion 7, Each may be refracted. Therefore, it is preferable to design the cross-sectional shape of the surface 8 on the emission surface 4b side of the second low refractive index portion 7 in consideration of the refraction angle at the surface 8.
In this embodiment, the center portion of the surface 8 on the exit surface 4b side of the second low refractive index portion 7 is a flat surface 8a. However, this is a convex surface or a concave surface, and the emitted light L0 at the center portion is a surface. It is also possible to further adjust the intensity distribution when the light passes through 8.

  The number, position, area, inclination angle, etc. of the plurality of reflecting surfaces can be arbitrarily controlled according to the desired intensity distribution in the plane of the exit surface. Since the exit surface is located opposite to the entrance surface, not only the light reflected by the reflection surface but also the light transmitted without reflection is emitted from the exit surface, and the amount of light exiting from the entrance surface or side surface is extremely reduced. Therefore, the light from the light source 3 can be used efficiently.

13 to 14 show a surface light emitting device according to a second embodiment as a reference example . The schematic configuration of the surface light emitting device 100 includes a light guide plate 40 having one side surface as an incident surface 40a and the other side surface as an output surface 40b, and a light source 3 that makes light incident on the incident surface 40a of the light guide plate 40. The first reflection part 1 having the plurality of first reflection surfaces 1a, 1b, 1c, 1d, and 1e described above is provided on the incident surface 40a side, and the second reflection surface 2a described above is provided on the emission surface 40b side. A second reflection unit 2.

According to the surface light emitting device 100 of the present embodiment, the incident light L from the light source 3 is branched into a plurality of outgoing lights L0, L1, L2, L3, L4, and L5, as in the first embodiment, and the light guide plate The light can be emitted from a wide range of the 40 emission surfaces 40b, so that planar light emission with high uniformity is possible.
Further, since at least one (both in FIGS. 13 to 14) of the first reflecting portion 1 and the second reflecting portion 2 is provided so as to be exposed on the outer surface of the light guide plate 40, the first reflecting portion 1. And the shaping | molding of the 2nd reflection part 2 becomes easy.
In the present embodiment, the material and shape of the light guide plate 40 can be the same as those of the light guide plate 4 (more specifically, the high refractive index portion 5) of the first embodiment described above.

As shown in FIG. 14, a reflective film 20 can be provided on each of the plurality of first reflecting surfaces 1a, 1b, 1c, 1d, and 1e in the first reflecting portion 1. As a result, the light reflected and diffused inside the light guide plate 40 can be prevented from being transmitted from the exit surface 40b to the opposite side, and the reflectance toward the exit surface 40b can be increased, thereby further improving the light utilization efficiency. It becomes possible to do.
The reflective film 20 can be formed by various methods such as vapor deposition of metal (Al, Ag, etc.) and metal oxide (eg, dielectric multilayer film), sputtering, metal plating, and the like.
The reflection film 20 may be provided on at least the first reflection surfaces 1a, 1b, 1c, 1d, and 1e, and further, the reflection film 20 is also formed on the surfaces 11a, 11b, 11c, and 11d between the first reflection surfaces. May be formed. As shown in FIG. 14, the reflection film 20 is continuously formed over the entire first reflection portion 1 including the first reflection surfaces 1a, 1b, 1c, 1d, and 1e and the surfaces 11a, 11b, 11c, and 11d therebetween. If provided, the formation pattern of the reflective film 20 becomes simple, and the production of the reflective film 20 becomes easy.

As mentioned above, although this invention has been demonstrated based on suitable embodiment, this invention is not limited to the above-mentioned example, Various modifications are possible in the range which does not deviate from the summary of this invention.
In the present invention, as shown in FIG. 5, the plurality of reflecting surfaces may be one or more selected from a flat surface 21, a convex surface 22, a concave surface 23, or a textured shape 24.

At least one of the plurality of first reflection surfaces in the first reflection portion is a convex surface 22 (a shape protruding from the low refractive index portion side toward the high refractive index portion side) or a concave surface 23 (of the high refractive index portion). If the shape is concave from the side toward the side of the low refractive index portion, there is an effect as a lens, and the emitted light can be diverged or converged. In addition, when at least one of the plurality of first reflecting surfaces in the first reflecting portion has a textured shape 24 (a rough surface such as a satin-like shape or a sandy shape) made of fine irregularities, the light incident on the reflecting surface Can be diffused. Therefore, the intensity distribution of the emitted light can be controlled as desired by arbitrarily combining these surface shapes.
The roughening treatment for forming the embossed shape can be carried out by locally applying an embossing process such as sandblasting, etching, or transfer from a mold.

FIG. 6 shows a plurality of first reflections such that as the distance from the light source 3 increases in the direction along the incident surface 4a, the average emission direction of the emitted light L0, L1, L2, L3, L4, and L5 is inclined toward the outer circumferential direction. This is an example in which the inclination angles of the surfaces 1a, 1b, 1c, 1d, and 1e are adjusted. According to the example shown in FIG. 6, it is possible to make the light emission area wider than in the example shown in FIG.
Although not shown in particular, contrary to FIG. 6, the inclination angle of the first reflecting surface is adjusted so that the average emission direction of the light reflected by the plurality of first reflecting surfaces is inclined toward the center of the light guide plate. It is also possible to do. Moreover, it is also possible to configure so that the average emission direction of the light reflected by the plurality of first reflecting surfaces is mixed with those inclined toward the outer periphery of the light guide plate and those inclined toward the center. is there.

The surface light emitting device 15 illustrated in FIG. 7 includes a light diffusion layer 14 that diffuses light on the light exit surface 4 b of the light guide plate 4. Examples of the light diffusion layer 14 include white printing, groove processing, dot processing, roughening processing (sand blasting, etching, embossing, etc.) and the like. Any one or a combination of these can be selected as appropriate in consideration of cost, workability, and the like. Thereby, the intensity distribution of the light emitted from the emission surface 4b can be made more uniform.
When the light diffusing layer is provided on the light guide plate 40 having a curved exit surface 40b as shown in FIGS. 13 to 14, the light diffusing layer does not necessarily need to be in close contact with the exit surface. For example, a light diffusing plate in which a light diffusing layer is provided on another transparent substrate can be laminated on the light exit surface side of the light guide plate.

In FIG. 8, the light guide plate includes a first portion 41 positioned between the incident surface 4 a and the first reflecting portion 1, and a second portion positioned between the first reflecting portion 1 and the second reflecting portion 2. An example is shown that is divided into three parts including a part 42 and a third part 43 located between the second reflecting part 2 and the exit surface 4b. The dividing surface 44 between the first portion 41 and the second portion 42 and the dividing surface 45 between the second portion 42 and the third portion 43 are precisely matched by, for example, a flat surface or a conical surface (tapered surface). be able to.
When a reflective film is provided on the first reflective portion 1, it is preferable to form the reflective film before combining the first portion 41 and the second portion 42.

  The outer shape of the side surface of the light guide plate may be a polygon such as a rectangle (square, rectangle) as shown in FIGS. In the case of the light guide plate 16 shown in FIGS. 9 and 10, the light source 3 is arranged at the center of the light guide plate 16, and the first reflecting portion 1 and the second reflecting portion 2 are similar in shape to the outer shape of the light guide plate 16. It is said. Although not particularly illustrated, the side surface of the light guide body may have a planar shape different from that of the reflection surface, such as a concentric reflection surface formed inside the light guide plate having a rectangular side surface.

The installation position of the light source is not limited to the center of the light guide plate, and the light source can be installed at a position offset from the center. Further, the outer shape of the side surface of the light guide plate 17 can be semicircular as shown in FIG. 11, or the outer shape of the side surface of the light guide plate 18 can be fan-shaped as shown in FIG. In this case, the 1st reflection part 1 and the 2nd reflection part 2 can also be provided in the arbitrary ranges whose circumferential direction centering on the light source 3 is less than 360 degrees.
The circumferential angle around the light source 3 is preferably about 180 ° or about 90 ° when the lighting device is installed so as to be in contact with the wall surface or corner. Moreover, since it attaches to the protruding corner | angular parts, such as a column surface, it is also possible to make the angle of the circumferential direction centering on the light source 3 into about 270 degrees.

  A plurality of light sources may be used for one light guide plate. In this case, the 1st reflection part which has several 1st reflection surfaces by this invention, and the 2nd reflection part which has a 2nd reflection surface can also be provided for every light source.

DESCRIPTION OF SYMBOLS 1 ... 1st reflection part, 1a, 1b, 1c, 1d, 1e ... Several 1st reflection surface, 2 ... 2nd reflection part, 2a ... 2nd reflection surface, 3 ... Light source, 4, 16, 17, 18, 40 ... light guide plate, 4a, 40a ... incident surface, 4b, 40b ... outgoing surface, 5 ... high refractive index portion, 6 ... first low refractive index portion, 7 ... second low refractive index portion, 8: Surface on the exit surface side of the second low refractive index portion, 8a: Flat surface, 9 ... Surface on the incident surface side of the first low refractive index portion, 10, 15, 100 ... Surface light emitting device, 11a, 11b , 11c, 11d ... surfaces between the reflecting surfaces, 12 ... a surface parallel to the incident surface, 13 ... a line perpendicular to the incident surface, 14 ... a layer for diffusing light (light diffusion layer), 20 ... a reflecting film, 21 ... Plane, 22 ... convex surface, 23 ... concave surface, 24 ... embossed shape, 41 ... part between the incident surface and the first reflecting part, 42 ... part between the first reflecting part and the second reflecting part, 43 ... No. Portion between the reflective portion and the exit surface of, 44, 45 ... dividing plane.

Claims (8)

A light guide plate having one side surface as an incident surface and the other side surface as an output surface, and a light source that makes light incident on the incident surface of the light guide plate,
The light guide plate includes a first reflecting portion located on the incident surface side and a second reflecting portion located on the emitting surface side, and the incident surface and the emitting surface are parallel to each other,
The first reflecting portions are provided at a predetermined interval so as to increase a distance from a surface including the incident surface as the distance from the light source increases along a direction parallel to the incident surface. A plurality of first reflecting surfaces each having a shape in which the distance from the surface including the incident surface increases as the distance from the light source increases along the direction, and the plurality of first reflecting surfaces in the first reflecting portion includes: , And an interface with a low refractive index portion consisting of a cavity provided inside the light guide plate,
The second reflecting portion includes a second reflecting surface having a shape in which a distance from a surface including the incident surface increases continuously with distance from the light source along a direction parallel to the incident surface , The second reflecting surface in the second reflecting portion is an interface with the low refractive index portion consisting of a cavity provided inside the light guide plate,
The light guide plate includes a first part located between the incident surface and the first reflecting part, a second part located between the first reflecting part and the second reflecting part, Divided into three parts consisting of a third part located between the reflecting part and the exit surface, and the first part and the second part are separated by a plane or conical split surface. aligned Te, the surface emitting device according to claim is Rukoto been combined via the dividing plane of the planar or conical surface between said second portion and said third portion.   2. The surface light emitting device according to claim 1, wherein the plurality of first reflection surfaces in the first reflection unit are one or two or more selected from a flat surface, a convex surface, a concave surface, or a textured shape.   The surface light-emitting device according to claim 1, wherein the light guide plate is made of a material transparent to light from the light source.   The surface light-emitting device according to claim 1, further comprising a light diffusing layer on an emission surface of the light guide plate. The outer side surface of the light guide plate is polygonal, the first reflecting section and the second reflecting portion is any one of claims 1 to 4 that are similar in shape to match the outer shape of the light guide plate A surface light-emitting device according to item. The surface light-emitting device according to claim 5 , wherein an outer shape of a side surface of the light guide plate is rectangular . The surface emitting device according to any one of claims 1 to 4, wherein the outer side surface of the light guide plate is a semicircular or fan-shaped.   The surface emitting device according to claim 1, wherein a reflective film is provided on each of the plurality of first reflective surfaces in the first reflective portion.

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