JP2008147040A - Light guide plate and flat lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize effectively light from a light source without loss and obtain high luminance emitting light without reflection of the strong light from the light source. <P>SOLUTION: The flat lighting device 1 is equipped with a light guide plate 2, a light source 9, and a reflector 14. The light guide plate 2 has a front surface part 7 to emit light, a rear face part 8 on the side opposite to the front surface part 7, and side face parts 3 to cross the front surface part 7 and the rear face part 8, and has an opening part 5 of nearly circular shape at the inner side of at least one end part 4. The light source 9 emits the light radially in 360° and is installed in the opening part 5 of the light guide plate 2. The reflector 14 has reflection performance and covers the front surface part 7 and the side face parts 3 emitting the light of the light guide plate 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a substantially rectangular light guide plate in which a substantially circular opening is provided inside at least one end, and the outside of the side surface of the outer side is substantially similar to the opening. Is a light guide plate having a substantially opening-shaped end portion that protrudes outward from the side surface portion, and is finely formed on the outside of the substantially side surface portion that is similar to the opening portion or on the outside of the substantially opening shape shape. Applying convex or concave processing, applying fine convex or concave processing to the inner wall of the opening that connects the front and back surfaces, and tilting the side surface from the end of the approximate opening shape Or the middle part of the side parts having a plurality of inclinations is arranged so that the distance between the side parts facing each other is the shortest, and the front part and the back part are concentric with the opening. Concentric concave ridges, concentric convex ridges or concentric dot-shaped micro light deflecting elements are provided A light source and a light source that deflects light emitted in the thickness direction between the front surface portion and the back surface portion in the opening direction and provided with a reflection portion in the direction of 360 ° in the direction of the side surface is provided in the opening portion, so that light from the light source is not wasted The present invention relates to a light guide plate and a flat illumination device that can be effectively used to obtain high-luminance outgoing light, avoid the occurrence of dark portions and bright portions, and avoid reflection of strong light from a light source.

  2. Description of the Related Art Conventionally, there has been known a flat illumination device in which a light guide plate is formed in a polygonal shape, a corner portion of the light guide plate is an incident end surface portion, and a light source is disposed corresponding to the incident end surface portion.

  Further, there is also known a technique in which microprisms are formed in a concentric pattern on the surface, the center of the pattern corresponds to a point light source, and the point light source is provided in the vicinity or corner of the light guide plate.

  In addition, the angle at which each diffuse pattern is viewed from the light source on the surface opposite to the light exit surface is smaller in the region closer to the light source than in the region away from the light source. A surface light source device is known in which a diffusion pattern is randomly arranged in a circumferential direction centering on a light source at least in the vicinity of the light source.

  Furthermore, when printing a white light scattering agent on the opposite side of the exit surface of the conventional light guide plate, the incident end surface is increased even if the printed portion is increased as the distance from the incident end surface portion is increased or dots such as irregularities are provided on the light guide plate. The dots increased as the distance from the part increased.

In addition, as a conventional flat illumination device using a point light source such as an LED, a plurality of LEDs are arranged on the side surface of the light guide plate, and a convex or concave such as a prism is formed on the incident end surface portion of the light guide plate at a position facing these LEDs. It is also known that a shape is provided so that light rays reach part of the corners of both ends of the light guide plate.
JP 2001-184923 A JP 2001-143512 A JP-A-11-250714

  In the conventional flat illumination device in which the light guide plate described above is formed in a polygonal shape, and the light source is arranged corresponding to the incident end surface portion with the corner portion of the light guide plate as the incident end surface portion, the incident end surface portion is flat with respect to the light source. Therefore, only light from which the light from the light source travels at right angles to the incident end face portion is incident straight into the light guide plate, and the other light is refracted and incident. For this reason, in particular, the S wave in the light always has a reflectivity, the reflectivity is approximately 20% at an incident angle of 60 °, and the reflectivity is approximately 50% at an incident angle of approximately 80 °. Will be exceeded. Further, there is a problem that even the P wave has an incident angle of about 80 ° and the reflectance exceeds 20%, and the light from the light source is not used well.

  In addition, as described above, even in the case of a conventional configuration in which microprisms are formed in a concentric pattern on the surface, the center of the pattern corresponds to a point light source, and the point light source is provided in the vicinity or corner of the light guide plate. Because the directivity of the point light source is radial, even if the microprism is formed in a concentric pattern on the surface, the light from the light source can be completely guided into the light guide plate if the shape of the incident portion is flat. There is a problem that cannot be done.

  In addition, the angle at which the individual diffusion pattern is viewed from the light source on the surface opposite to the light exit surface is smaller in the region closer to the light source than in the region away from the light source. Even in the case of a surface light source device that is randomly arranged in the circumferential direction around the light source, at least in the vicinity of the light source, as in the case of the point light source described above, individual diffusion patterns are generated from the light source. The angle of view is smaller in the region closer to the light source than in the region away from the light source because the directivity of the point light source is radial, and the circumferential direction around the light source is simply the center of the light source. However, there is a problem that the light from the light source cannot be completely guided into the light guide plate if the shape of the incident portion is flat even if randomly arranged.

(Object of invention)
The present invention has been made in order to solve the above-described problems. The end portion of a general rectangular light guide plate is formed in an arc shape, and no incident end surface portion is provided on a side surface portion. A substantially circular opening is provided, and a light source that emits 360 ° radially without directivity is provided in the opening. The front and back portions are concentrically continuous or discontinuous with the opening. Concentric concave ridges and concentric convex ridges in which the angle between the apex is 45 ° to 174 ° and the angle between the inclined surface facing the opening and the front surface portion and the back surface portion is 3 ° to 67.5 ° Alternatively, a concentric dot-shaped minute light deflecting element is provided so that the light from the light source can be used efficiently without waste without negatively affecting the effective light exit surface area of the light guide plate, thereby obtaining high-brightness outgoing light. In addition, it is a flat illumination device that can avoid the occurrence of dark and bright areas and avoid the reflection of strong light from the light source. The
In addition, an end having a substantially opening shape that is a multiple of the opening is provided outside the side surface, or connected to the side surface with an inclination from the end of the approximately opening shape. The side surfaces having slopes are connected to each other from the end portions of the light guide plates and the respective substantially opening-type shapes, and the distance between the side portions facing each other at the middle portion of the adjacent end portions is the shortest distance. In addition, a mirror surface is provided without providing anything on the front surface or back surface outside the opening of the end portion, and concentric concave ridges or concentric convex ridges are provided on the front surface or back surface. A plurality of minute light deflecting elements are provided on the front surface portion and the back surface portion opposite to the side on which the light source is provided.
Further, fine convex or concave processing is performed on the outer side of the arc-shaped end portion or the end portion of the substantially opening shape, and fine convex or concave processing is performed on the inner wall of the opening portion.
With the light guide plate and the light source provided in the opening, the light directed toward the front surface and the back surface in the outer direction of the opening is not leaked to the outside, but remains in the light guide plate, and the bright line extends toward the center of the light guide plate. Generation of light can be mixed, light from multiple light sources can be mixed, light emission colors from light sources of different light emission colors can be mixed, and bright emission light free from spots can be obtained. An object of the present invention is to provide a light guide plate and a flat illumination device.

  The light guide plate according to claim 1 of the present invention is characterized by having a substantially circular opening through which light enters at least one end.

  Since the light guide plate according to the first aspect has a substantially circular opening through which light enters at least one end, light can be prevented from leaking outside the light guide plate.

  Furthermore, the light guide plate according to claim 2 is characterized in that the end portion has an outer side surface corresponding to the opening and has a size that is a multiple of the opening and an approximate shape of the opening.

  In the light guide plate according to claim 2, since the end portion is formed such that the outside of the side surface portion corresponding to the opening portion is a multiple of the opening portion and the shape of the opening portion, the end portion is substantially perpendicular to the outside of the side surface portion. Can be eliminated.

  The light guide plate according to claim 3 is characterized in that the end portion is provided outside the side surface portion and has a substantially opening portion shape having a size that is a multiple of the opening portion.

  In the light guide plate according to claim 3, since the end portion is provided outside the side surface portion and has a substantially opening shape that is a multiple of the size of the opening, the end portion that is substantially perpendicular to the outside of the side surface portion is formed. It can be eliminated and a large emission area from the light guide plate can be secured.

  Furthermore, the light guide plate according to claim 4 is characterized in that the side surface portion is connected with an inclination from the end portion of the substantially opening shape.

  In the light guide plate according to the fourth aspect, since the side surface portion is connected with an inclination from the end portion of the substantially opening shape, the side surface portion is used to guide the incident light from the opening portion into the light guide plate. be able to.

  Further, the light guide plate according to claim 5 connects the side portions with an inclination from each end portion of the substantially opening shape, and the distance between the side portions where the intermediate portions of the adjacent end portions face each other. Is the shortest distance.

  The light guide plate according to claim 5 connects the side surface portions with an inclination from each end portion of the substantially opening shape, and the distance between the side surface portions where the positions of the intermediate portions of the adjacent end portions face each other is the longest. Since the distance is short, the side surface can be used to guide the incident light from each opening into the light guide plate, and the side surface connected from each substantially opening shape is the same distance from the opening. be able to.

  Furthermore, the light guide plate according to claim 6 is characterized in that a fine convex shape and / or a concave shape processing is applied to the end portion on the outer side surface corresponding to the opening portion or on the outer side of the substantially opening portion shape.

  In the light guide plate according to the sixth aspect, since the end portion is subjected to fine convex shape and / or concave shape processing on the outer side of the side surface portion corresponding to the opening portion or the outer side of the substantially opening shape, the inside of the light guide plate from the opening portion. Of the light incident on the light, the light traveling in the end direction can be reflected in the inner direction of the light guide plate without being emitted to the outside by the fine convex shape or concave shape provided on the outer side surface of the end portion.

  The light guide plate according to claim 7 is characterized in that a fine convex shape and / or a concave shape processing is applied to the inner wall connecting the front surface portion and the back surface portion of the opening.

  In the light guide plate according to the seventh aspect of the invention, since the inner wall that connects the front surface portion and the back surface portion of the opening portion is subjected to fine convex or / and concave processing, the light guided from the opening portion into the light guide plate is the front surface portion. It can be diffused or condensed in the radial direction from the thickness direction with the back surface portion or the opening.

  Furthermore, the light guide plate according to claim 8 is provided with a concentric concave ridge or / and a concentric convex ridge or concentric dot-like micro-concentration that is concentrically continuous or discontinuous with the opening on the front surface and / or back surface. An optical deflection element is provided.

  The light guide plate according to claim 8 includes: a concentric concave ridge or / and a concentric convex ridge or concentric dot-shaped minute light deflection that is concentrically continuous or discontinuous with the opening on the front surface and / or back surface. Since the element is provided, the light guided into the light guide plate from the opening and the minute light deflection element are always connected in a perpendicular direction, and all the minute light deflection elements receive the same luminance with respect to the distance from the opening. Can do.

  The light guide plate according to claim 9 is provided with a plurality of micro light deflecting elements on the surface portion or the back surface portion opposite to the side where the concentric concave ridge or / and the concentric convex ridge is provided on the front surface portion and the back surface portion. It is characterized by that.

  The light guide plate according to claim 9 is provided with a plurality of micro light deflecting elements on the surface portion or the back surface portion opposite to the side where the concentric concave ridge or / and the concentric convex ridge is provided on the front surface portion and the back surface portion. Even if the incident angle with respect to the opposite surface does not reach the critical angle when the reflected light travels to the opposite surface provided with the concentric concave ridge or concentric convex ridge, the minute optical deflection element The incident angle that breaks the critical angle can be emitted to the outside.

  Furthermore, the light guide plate according to claim 10 is characterized in that the end portion is a mirror surface without providing anything on the front surface and the back surface in the outer direction of the opening.

  In the light guide plate according to claim 10, since the end portion is a mirror surface without providing anything on the surface portion and the back surface portion in the outside direction of the opening portion, the light is emitted from the surface portion and the back surface portion in the outside direction of the opening portion. Can be suppressed.

  The light guide plate according to claim 11 has concentric concave ridges and vertexes of the concentric convex ridges of 45 ° to 174 ° and has an inclined surface in the direction of the opening and parallel to the front surface portion or the back surface portion. The angle formed with the virtual horizontal plane is in the range of 3 ° to 67.5 °.

  The light guide plate according to claim 11 is a virtual horizontal plane in which the angle of the apex of the concentric concave ridge and the concentric convex ridge is 45 ° to 174 ° and has an inclined surface in the opening direction and parallel to the front surface portion or the back surface portion. Since the angle formed between the light beam and the light traveling from the opening into the light guide plate is a small angle inclined surface formed by the parallel virtual horizontal plane, the total reflected light exceeding the critical angle is generated. It is possible to obtain a totally reflected light which is once reflected on the front surface and the back surface by the inclined surface having a large angle formed with the parallel virtual horizontal plane and totally reflected again to travel in the opposite surface direction. it can.

Furthermore, the flat illumination device according to claim 12 has a front surface portion or / and a back surface portion that emits light, and a side surface portion that intersects with the front surface portion and the back surface portion, and is substantially circular inside at least one end portion. A light guide plate having an opening of
A light source that emits light radially at 360 °;
A reflector having reflectivity that covers the surface opposite to the light emitting surface of the light guide plate and the side surface portion;
A light source is provided in the opening.

The flat illumination device according to claim 12 has a front surface portion or / and a back surface portion that emits light, and a side surface portion that intersects with the front surface portion and the back surface portion, and a substantially circular opening inside at least one end portion. A light guide plate having a portion;
A light source that emits light radially at 360 °;
A reflector having reflectivity that covers the surface opposite to the light emitting surface of the light guide plate and the side surface portion;
Since the light source is provided in the opening, the light from the light source can be used effectively, the light from the light source can be prevented from leaking to the outside, and the light can reach a position away from the light source.

  In the planar illumination device according to claim 13, the light source deflects light emitted in the thickness direction of the front surface portion and the back surface portion by 360 ° in the direction of the side surface with a reflection portion in front of the emission direction. And

  In the flat illumination device according to claim 13, since the light source emits light emitted in the thickness direction of the front surface portion and the back surface portion and includes a reflection portion in front of the emission direction and deflects 360 ° in the direction of the side surface portion, directivity is improved. It can be emitted in all horizontal directions.

As described above, since the light guide plate according to the first aspect has the substantially circular opening that allows light to enter inside at least one end, light can be prevented from leaking outside the light guide plate.
Therefore, the light can be used effectively to the maximum, and high-intensity outgoing light that is uniform and free from spots can be obtained.

In the light guide plate according to claim 2, since the end portion is formed such that the outside of the side surface portion corresponding to the opening portion is a multiple of the opening portion and the shape of the opening portion, the end portion is substantially perpendicular to the outside of the side surface portion. Can be eliminated.
Therefore, it is possible to efficiently reflect light directed toward the side surface portion without hitting the plane and to prevent generation of bright lines in the central direction of the light guide plate.

In the light guide plate according to claim 3, since the end portion is provided outside the side surface portion and has a substantially opening shape that is a multiple of the size of the opening, the end portion that is substantially perpendicular to the outside of the side surface portion is formed. It can be eliminated and a large emission area from the light guide plate can be secured.
Therefore, it is possible to efficiently reflect light directed toward the side surface portion without hitting the plane and to prevent generation of bright lines in the central direction of the light guide plate. In addition, it is possible to prevent the prism body, the liquid crystal panel, and the like provided in the upward direction from being affected by heat from the light source.

In the light guide plate according to the fourth aspect, since the side surface portion is connected with an inclination from the end portion of the substantially opening shape, the side surface portion is used to guide the incident light from the opening portion into the light guide plate. be able to.
For this reason, the light utilization rate is good, the light can reach a position away from the light source, and bright outgoing light can be obtained.

The light guide plate according to claim 5 connects the side surface portions with an inclination from each end portion of the substantially opening shape, and the distance between the side surface portions where the positions of the intermediate portions of the adjacent end portions face each other is the longest. Since the distance is short, the side surface can be used to guide the incident light from each opening into the light guide plate, and the side surface connected from each substantially opening shape is the same distance from the opening. can do.
Therefore, the utilization factor of light is good and light can reach a position away from the light source, and bright outgoing light without spots can be obtained.

In the light guide plate according to the sixth aspect, since the end portion is subjected to fine convex shape and / or concave shape processing on the outer side of the side surface portion corresponding to the opening portion or the outer side of the substantially opening shape, the inside of the light guide plate from the opening portion. Of the light incident on the light, the light traveling in the end direction can be reflected in the inner direction of the light guide plate without being emitted to the outside by the fine convex shape or concave shape provided on the outer side surface of the end portion.
For this reason, light from the light source can be used without waste, and more light can be introduced into the light guide plate, so that bright emitted light can be obtained. In addition, when light sources having different emission colors are provided in the openings, the light diffuses and proceeds toward the inside of the light guide plate, so that different emission colors can be mixed better.

In the light guide plate according to the seventh aspect of the invention, since the inner wall that connects the front surface portion and the back surface portion of the opening portion is subjected to fine convex or / and concave processing, the light guided from the opening portion into the light guide plate is the front surface portion. It can be diffused or condensed in the radial direction from the thickness direction with the back surface portion or the opening.
Therefore, the light from the opening can be spread more widely, the light from the opening at each end can be mixed, and brighter light can be emitted, and further from different ends Different emission colors can be mixed thoroughly. For example, by providing R (red light emission color) G (green light emission color) B (blue light emission color) in the opening at each end, a clearer white light can be obtained.

The light guide plate according to claim 8 includes: a concentric concave ridge or / and a concentric convex ridge or concentric dot-shaped minute light deflection that is concentrically continuous or discontinuous with the opening on the front surface and / or back surface. Since the element is provided, the light guided into the light guide plate from the opening and the minute light deflection element are always connected in a perpendicular direction, and all the minute light deflection elements receive the same luminance with respect to the distance from the opening. Can do.
Therefore, bright outgoing light without spots can be obtained.

The light guide plate according to claim 9 is provided with a plurality of micro light deflecting elements on the surface portion or the back surface portion opposite to the side where the concentric concave ridge or / and the concentric convex ridge is provided on the front surface portion and the back surface portion. Even if the incident angle with respect to the opposite surface does not reach the critical angle when the reflected light travels to the opposite surface provided with the concentric concave ridge or concentric convex ridge, the minute optical deflection element The incident angle that breaks the critical angle can be emitted to the outside.
Therefore, more light existing in the light guide plate can be emitted from the emission surface, and a brighter emission surface can be obtained.

In the light guide plate according to claim 10, since the end portion is a mirror surface without providing anything on the surface portion and the back surface portion in the outside direction of the opening portion, the light is emitted from the surface portion and the back surface portion in the outside direction of the opening portion. Can be suppressed.
Therefore, the light directed toward the front surface and the back surface in the outer direction of the opening can be retained in the light guide plate without leaking to the outside, and the light can be used for light emitted from a necessary light exit surface.

The light guide plate according to claim 11 is a virtual horizontal plane in which the angles of the vertices of the concentric concave ridge and the concentric convex ridge are 45 ° to 174 ° and have an inclined surface in the opening direction and parallel to the front surface portion or the back surface portion. Since the angle formed between the light beam and the light traveling from the opening into the light guide plate is a small angle inclined surface formed by the parallel virtual horizontal plane, the total reflected light exceeding the critical angle is generated. It is possible to obtain a totally reflected light which is once reflected on the front surface and the back surface by the inclined surface having a large angle formed with the parallel virtual horizontal plane and totally reflected again to travel in the opposite surface direction. it can.
Therefore, it can radiate | emit from the surface which provided the concentric concave ridge and the concentric convex ridge, and the emitted light of the direction away from an opening part or the direction approaching an opening part can be obtained.

The flat illumination device according to claim 12 has a front surface portion or / and a back surface portion that emits light, and a side surface portion that intersects with the front surface portion and the back surface portion, and a substantially circular opening inside at least one end portion. A light guide plate having a portion;
A light source that emits light radially at 360 °;
A reflector having reflectivity that covers the surface opposite to the light emitting surface of the light guide plate and the side surface portion;
Since the light source is provided in the opening, the light from the light source can be used effectively, the light from the light source can be prevented from leaking to the outside, and the light can reach a position away from the light source.
Therefore, it is possible to mix light from multiple light sources, especially to mix emission colors from light sources with different emission colors, and to prevent bright lines from appearing and preventing reflection of the light source itself. it can.

In the flat illumination device according to claim 13, since the light source emits light emitted in the thickness direction of the front surface portion and the back surface portion and includes a reflection portion in front of the emission direction and deflects 360 ° in the direction of the side surface portion, directivity is improved. It can be emitted in all horizontal directions.
Therefore, it is possible to avoid the reflection of strong light from the light source itself, and it is possible to obtain outgoing light with good appearance.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The present invention has a substantially circular opening that allows light to enter inside at least one end, or corresponds to the substantially circular opening by projecting the end outward from the side surface. The outside of the side surface is a positive multiple of the size of the opening and the shape of the opening, and the end is subjected to fine convex or concave processing on the outside of the side surface corresponding to the opening, and the surface of the opening The inner wall that connects the back and back parts is processed to have a fine convex or concave shape, and the edges are mirrored on the front and back surfaces in the outer direction of the opening, and open on the other front and back parts. Concentric continuous or discontinuous concentric concave ridges, concentric convex ridges or concentric dot-shaped micro light deflecting elements are provided, and the side surface of the light guide plate is inclined from the end of the substantially opening shape The distance between the side parts where the middle part of the adjacent end parts face each other is the shortest distance. A planar surface provided with a light guide plate, a light source that emits light radially at 360 °, and a reflective body that covers a surface opposite to the light emitting surface of the light guide plate and a side surface portion; An illumination device is provided.

  1 and 2 are schematic perspective views of a flat illumination device according to the present invention, FIGS. 3 and 4 are schematic front views of a light guide plate according to the present invention, and FIG. 5 is a schematic front view of the light guide plate according to the present invention. FIGS. 6 to 13 are a schematic cross-sectional view and a light locus diagram of the light guide plate according to the present invention.

  As shown in FIG. 1, the flat illumination device 1 includes a light guide plate 2, a light source 9, and a reflector or case 14.

The light guide plate 2 is formed of a transparent acrylic resin (PMMA) or polycarbonate (PC) having a refractive index of about 1.4 to 1.7. The light guide plate 2 shown in FIG. 1 has a substantially rectangular shape, four side surface portions 3, four end portions 4 to which the side surface portions 3 are connected to each other, a surface portion 7 that emits light, and the surface portion 7 And a back surface portion 8 located on the opposite side. Further, inside the four end portions 4 of the light guide plate 2, incident portions of substantially circular opening portions 5 for guiding light from the light source 9 are provided.
Here, the opening 5 is used as the incident part, and the incident part is in the direction of the four end parts 4 of the four side surface parts 3 of the light guide plate 2 having a substantially rectangular shape. Not.

  Further, the light guide plate 2 has a uniform distance (thickness of the light guide plate 2) between the front surface portion 7 and the back surface portion 8, but it is minimized (thin) near the opening portion 5, or the opening portion. A shape that is maximum (thick) in the vicinity of 5 may be used.

  The end 4 has a size obtained by multiplying the outer side portion of the side surface 3 corresponding to the substantially circular opening 5 by a multiple of the opening 5 similar to the shape of the opening 5.

The opening 5 includes a light source 9 therein, and the entire wall of the opening 5 serves as an incident portion to guide light from the light source 9 into the light guide plate 2.
In FIG. 1, the opening 5 is a through hole, but the opening 5 is provided on the back surface 8 side so as to be opposite to the emission surface, and the back surface portion is a flat surface having nothing on the surface portion 7. A concave portion may be provided on the 8 side, and an opening 5 of the concave portion may be provided at least on the front surface portion 7 or the back surface portion 8.

The light incident on the light guide plate 2 having the above configuration travels into the light guide plate 2 in a range where the refraction angle γ satisfies the expression 0 ≦ | γ | ≦ Sin ⁻¹ (1 / n). For example, since the refractive index of acrylic resin, which is a resin material used for the general light guide plate 2, is about n = 1.49, the refraction angle γ refracted at the incident portion of the opening 5 is γ = 0 ± 42. Within the range of °°.

  Further, the light incident on the light guide plate 2 within the range of the refraction angle γ = 0 to ± 42 ° is Sin α = (1 / n) at the boundary surface between the light guide plate 2 and the air layer (n = 1). The critical angle can be expressed by an equation. For example, since the refractive index of acrylic resin, which is a resin material used for the general light guide plate 2, is about n = 1.49, the critical angle α is about α = 42 °. For this reason, there are no grooves or the like for deflecting light beams on the front surface portion 7 and the back surface portion 8 of the light guide plate 2, or the thickness of the light guide plate 2 gradually decreases from the direction of the opening 5 of the incident portion of the light guide plate 2. If the critical angle α is not exceeded so that the overall inclination angle is about 6 °, the light in the light guide plate 2 travels in the direction of the counter opening 5 while being totally reflected by the front surface portion 7 and the back surface portion 8. .

In addition, although not shown, a fine convex shape and / or a concave shape processing is performed on a portion outside the side surface portion 3 corresponding to the opening portion 5 of the end portion 4. For example, in the thickness direction of the light guide plate 2 (between the front surface portion 7 and the back surface portion 8), a fine prism shape, a triangular pyramid, an arc-shaped dot, or the like is provided in the arc-shaped portion of the end portion 4. As a result, the light that has traveled in the direction of the end 4 among the light that has entered the light guide plate 2 from the opening 5 is caused by the fine convex shape or concave shape applied to the outer side portion of the side surface portion 3 that is the end portion 4. The light can be reflected again toward the inside of the light guide plate 2 without being emitted to the outside.
Therefore, light from the light source 9 can be used without waste, more light can be introduced into the light guide plate 2, and bright outgoing light can be obtained. Further, when the light source 9 having a different emission color is provided in the opening 5, the light diffuses and proceeds toward the inside of the light guide plate 2. For this reason, different emission colors can be mixed better.

Furthermore, although not shown in the drawing, the inner wall connecting the front surface portion 7 and the back surface portion 8 of the opening 5 is subjected to fine convex or / and concave processing. For example, a fine prism shape, a triangular pyramid, an arc-shaped dot, or the like is provided in the thickness direction of the light guide plate 2 (between the front surface portion 7 and the back surface portion 8).
Thereby, the light guided into the light guide plate 2 from the opening 5 can be diffused or condensed in the thickness direction of the front surface portion 7 and the back surface portion 8 or in the radial direction from the opening 5. As a result, the light from the opening 5 can be spread more widely, the light from the opening 5 at each end 4 can be mixed, and brighter light can be emitted.
Further, different emission colors from the openings 5 at the plurality of different end portions 4 can be completely mixed. For example, if R (red light emission color) G (green light emission color) B (blue light emission color) is provided in the opening 5 of each end portion 4, more beautiful white light can be obtained.

The front surface 7 and the back surface 8 are provided with concentric concave ridges 10 or / and concentric convex ridges 11 or concentric dot-shaped micro light deflecting elements 12 that are concentrically continuous or discontinuous with the opening 5.
Although not shown, the dot-shaped minute light deflection element 12 has a convex shape or a concave shape such as a part of a sphere and an elliptical sphere, and a triangular pyramid, a cone, a quadrangular pyramid, a triangular prism, a quadrangular prism, and a cylinder.

Furthermore, nothing is provided in the outer side direction of the opening part 5 of the front surface part 7 of the light guide plate 2 and the end part 4 of the back surface part 8, and it is a mirror surface.
Therefore, the emission from the front surface portion 7 and the back surface portion 8 in the outer direction of the opening portion 5 can be suppressed, and the light directed to the front surface portion 7 and the back surface portion 8 in the outer direction of the opening portion 5 is guided without leaking to the outside. The light can be retained in the light plate 2 and used for light emitted from an emission surface that requires the light.

  6 and 8, as shown in FIG. 2, concentric concave ridges 10 (or concentric dots formed concentrically and continuously with the opening 5 on the back surface 8 side of the light guide plate 2. FIG. 6 is a locus diagram of light when a triangular prism-shaped concave light deflecting element 12) is provided.

  In FIG. 6, the concentric concave ridge 10 has a small apex angle θ <b> 1 and a large angle θ formed by the back surface portion 8 and the inclined surface 10 a. In FIG. 6, among the light incident on the light guide plate 2, the light beam L 0 having the maximum refraction angle γ = 42 ° is totally reflected by the back surface portion 8 of the light guide plate 2. The total reflected light Lbr is totally reflected again by the inclined surface 10a of the concentric concave ridge 10 when traveling in the surface portion 7 direction. The reflected light Lrr travels in the direction of the surface portion 7 substantially perpendicularly and is emitted from the surface portion 7 as emitted light L00.

  Further, in FIG. 8, the concentric concave ridge 10 has a large apex angle θ1 and a small angle θ formed by the back surface portion 8 and the inclined surface 10a. In FIG. 8, a light ray L0mx having a maximum refraction angle γ = 42 ° or a light ray L0mi having a small refraction angle γ out of the light incident into the light guide plate 2 travels in the direction of the back surface portion 8 of the light guide plate 2. Total reflection is performed on the inclined surface 10a. Then, the light beam L0mx corresponding to the incident angle travels in the direction of the surface portion 7 as the reflected light Lrmx with a small reflection angle, and is emitted from the surface portion 7. The light ray L0mi travels in the direction of the surface portion 7 as a reflected light Lrmi with a large reflection angle, and exits from the surface portion 7 away from the concentric concave ridge 10.

  7 shows the detailed light trajectory of FIG. 6, FIG. 9 shows the detailed light trajectory of FIG. 8, and the apex angle θ1 of the concentric concave ridge 10 is 45 ° to 174 °. An example is shown in which an angle θ formed by a virtual horizontal plane having an inclined surface 10a in the direction of the opening 5 (not shown) and parallel to the front surface portion 7 or the back surface portion 8 is in the range of 3 ° to 67.5 °.

  The concentric concave ridge 10 of FIG. 7 has a vertex angle θ1 as small as 45 ° (sharp), an angle θ formed between the back surface 8 and the inclined surface 10a is 66 °, and an angle θ2 formed between the inclined surface 10b is 69 °. Consists of.

  In FIG. 7, the light incident on the light guide plate 2 is a light beam having a relatively large refraction angle γ (γ = 30 to 42 °), and the refraction angle γ is close to the maximum (γ = about 42 °). The light beam L02 is totally reflected by the back surface portion 8 toward the back surface portion 8 of the light guide plate 2. The total reflected light L12 is totally reflected again by the inclined surface 10a of the concentric concave ridge 10 when traveling in the direction of the surface portion 7, and proceeds in the direction of the surface portion 7 substantially vertically as the reflected light L22 and is emitted from the surface portion 7.

  Similarly, light L01 having a relatively large refraction angle γ (about γ = 30 to 42 °) among light incident on the light guide plate 2 and having a slightly small refraction angle γ (about γ = 30 °). The light beam L03 is totally reflected by the rear surface portion 8 toward the rear surface portion 8 of the light guide plate 2. The total reflected light L11 and the total reflected light L13 are again totally reflected by the inclined surface 10a of the concentric concave ridge 10 when traveling in the direction of the surface portion 7, and are slightly reflected on the surface portion on the incident light side as the reflected light L21 and the reflected light L23. The light travels in 7 directions and exits from the surface portion 7.

  In this way, the light traveling from the opening 5 into the light guide plate 2 is totally reflected once by the front surface portion 7 and the back surface portion 8 by the inclined surface 10a having a large angle θ formed by the parallel virtual horizontal surface at the concentric concave ridge 10. Then, the reflected light is totally reflected again, and the totally reflected light traveling in the direction of the opposing surface can be obtained. And it can radiate | emit from the surface which provided the concentric concave ridge 10, and the emitted light of the direction which approaches the opening part 5 can be obtained.

  The concentric concave ridge 10 shown in FIG. 9 has a large apex angle θ1 of 166 ° (gradual), an angle θ formed by the back surface 8 and the inclined surface 10a is 7 °, and an angle θ2 formed by the inclined surface 10b (not shown). ) Consists of 7 °.

  In FIG. 9, among the light incident on the light guide plate 2, a light beam L0L1 having a small refraction angle γ (γ = about 10 to 31 °) and a small refraction angle γ (γ = about 10 °) is When going in the direction of the back surface 8 of the light guide plate 2, the light advances toward the inclined surface 10a of the concentric concave ridge 10 at a large incident angle and is totally reflected at a large reflection angle. The total reflected light LrL1 travels in the direction of the surface portion 7 so as to be slightly along the back surface portion 8 and the like, and is emitted from the surface portion 7 away from the concentric concave ridge 10.

  Of the light incident on the light guide plate 2, a light beam L0L3 having a slightly small refraction angle γ (γ = about 10 to 31 °) and a relatively large refraction angle γ (γ = about 31 °) is When the light guide plate 2 proceeds in the direction of the back surface 8, total reflection is performed on the inclined surface 10 a of the concentric concave ridge 10. The total reflected light LrL3 travels in the direction of the surface portion 7 and is emitted from the surface portion 7.

  Similarly, of the light incident on the light guide plate 2, a light beam L0L2 having a slightly small refraction angle γ (γ = about 10 to 31 °) and a relatively small refraction angle γ (about γ = 22 °). Is totally reflected by the inclined surface 10 a of the concentric concave ridge 10 when proceeding in the direction of the back surface portion 8 of the light guide plate 2. The total reflected light LrL2 proceeds in the direction of the surface portion 7 and is emitted from the surface portion 7.

  In this way, the light traveling from the opening 5 into the light guide plate 2 is opposed by the inclined surface 10 a having a small angle θ formed by the parallel virtual horizontal plane (the front surface portion 7 and the back surface portion 8) at the concentric concave ridge 10. Total reflection light traveling in the surface direction can be obtained. Moreover, the total reflected light can exceed the critical angle α, and the outgoing light in the direction away from the opening 5 can be obtained by proceeding to the opposing surface away from the concentric concave ridge 10.

  10 and 12 show concentric convex ridges 11 concentrically or discontinuously provided on the surface 7 side of the light guide plate 2 on the surface 7 side, or concentrically dotted triangular prisms. FIG. 6 is a locus diagram of light when a convex minute light deflection element 12 is provided.

  In FIG. 10, the apex angle θ1 is small, and the concentric convex ridge 11 has a large angle θ (θ2) formed by the surface portion 7 and the inclined surface 11a (inclined surface 11b). In FIG. 10, the light ray L0 having the maximum refraction angle γ = 42 ° among the light incident on the light guide plate 2 travels into the concentric convex portion 11 when traveling in the direction of the surface portion 7 of the light guide plate 2, and concentric convex ridges. Since the incident angle is small with respect to the 11 inclined surfaces 11b, it is refracted. This refracted light is emitted as outgoing light L00 from the surface portion 7 slightly upward. Further, the light beam L0m having a slightly large refraction angle γ travels into the concentric convex ridge 11 and has a small incident angle with respect to the inclined surface 11b, and thus is emitted as the emitted light Lmp from the surface portion 7 without being refracted so much.

  In FIG. 12, the apex angle θ <b> 1 is large, and the concentric convex ridge 11 has a small angle θ (θ <b> 2) formed by the surface portion 7 and the inclined surface 11 a (inclined surface 11 b). In FIG. 12, the light ray L0 having the maximum refraction angle γ = 42 ° among the light incident on the light guide plate 2 travels into the concentric convex ridge 11 and has a critical angle α at the marginal surface 11b of the concentric convex ridge 11. The light is refracted so as to break, and is emitted from the surface portion 7 as the light beam Lp1 along the surface portion 7. The light L0r having a very small refraction angle γ travels into the concentric convex ridge 11 and has a large incident angle with respect to the inclined surface 11b. Therefore, the light L0r is totally reflected by the inclined surface 11b and is reflected again into the light guide plate 2. As shown in FIG.

  Here, FIG. 11 shows the detailed light trajectory of FIG. 10, FIG. 13 shows the detailed light trajectory of FIG. 12, and the apex angle θ1 of the concentric convex ridge 11 is 45 ° to 174 °. An example is shown in which the angle θ formed by a virtual horizontal plane having an inclined surface 11b in the direction of the opening 5 and parallel to the front surface portion 7 or the back surface portion 8 is in the range of 3 ° to 67.5 °.

  The concentric convex ridge 11 shown in FIG. 11 has an apex angle θ1 as small as 45 ° (sharp), an angle θ2 formed by the surface portion 7 and the inclined surface 11b is 69 °, and an angle θ formed by the inclined surface 11a is 66 °. Consists of.

  In FIG. 11, the light incident on the light guide plate 2 is a light beam having a relatively large refraction angle γ (γ = 25 to 42 °) and the refraction angle γ is close to the maximum (γ = 42 °). The light ray L011 travels into the concentric convex ridge 11 provided on the surface portion 7 of the light guide plate 2 and has a small incident angle with respect to the inclined surface 11b of the concentric convex ridge 11, and therefore is refracted by the inclined surface 11b. The light is emitted from the portion 7 (concentric convex ridge 11) as an outgoing light beam L110.

  Similarly, light having a relatively large refraction angle γ (γ = 25 to 42 °) among light incident on the light guide plate 2 and a light ray L012 having a refraction angle γ of the middle (γ = about 35 °). ) And the light beam L013 (about γ = 25 °) proceed into the concentric convex ridge 11 provided on the surface portion 7 of the light guide plate 2, and are inclined at a small incident angle on the inclined surface 11b of the concentric convex ridge 11. The light is refracted a little at the surface 11b and emitted from the surface portion 7 (concentric convex ridge 11) as an outgoing light beam L120 and an outgoing light beam L130.

  In this way, the light traveling from the opening 5 into the light guide plate 2 is refracted by the inclined surface 11b having a large angle θ2 formed with the parallel virtual horizontal surface at the concentric convex ridge 11 so as to be separated from the surface portion 7 upward. The outgoing light can be obtained.

  The concentric convex ridge 11 shown in FIG. 13 has a large apex angle θ1 of 166 ° (slow), an angle θ formed by the surface portion 7 and the inclined surface 11a is 7 °, and an angle θ2 formed by the inclined surface 11b is 7 °. Consists of.

  In FIG. 13, among the light incident on the light guide plate 2, a light ray L 0 having a refraction angle γ of the maximum refraction angle (γ = about 42 °) is within the concentric convex ridge 11 provided on the surface portion 7 of the light guide plate 2. Then, since the incident angle is about the critical angle α on the inclined surface 11b of the concentric convex ridge 11, it is refracted at a large outgoing angle by the inclined surface 11b and is emitted from the surface portion 7 (concentric convex ridge 11) as an outgoing light beam Lp1. The light is emitted along the surface portion 7 (concentric convex ridge 11). The outgoing light Lp1 is 42 ° + 7 ° = 49 ° from the maximum refraction angle γ = 42 ° and the inclination angle of the concentric convex ridge 11 (angle θ2 = 7 °), and can break the critical angle at 48 °. .

  Of the light incident on the light guide plate 2, the light L0r1 having a relatively small refraction angle γ (about γ = 30 °) out of light rays having a small refraction angle γ (about γ = 10-30 °) is The light travels into the concentric convex ridge 11 provided on the front surface portion 7 of the light guide plate 2, undergoes total reflection at the inclined surface 11 b, and proceeds in the direction of the back surface portion 8 as reflected light L0rr1.

  Similarly, among the light incident on the light guide plate 2, the light L0r2 having a small refraction angle γ (γ = about 10 °) and a small refraction angle γ (about γ = 10 °) is guided. Proceeding into the concentric convex ridge 11 provided on the front surface portion 7 of the optical plate 2, total reflection is performed on the inclined surface 11b, and the reflected light L0r22 proceeds in the direction of the back surface portion 8.

  In this way, the light traveling from the opening 5 into the light guide plate 2 is particularly refracted by the inclined surface 11b having a small angle θ2 formed by the parallel virtual horizontal surfaces (the front surface portion 7 and the back surface portion 8) at the concentric convex ridges 11. Some light rays having an angle γ of the maximum refraction angle γ are refracted by the inclined surface 11 b and emitted along the surface portion 7 of the light guide plate 2. However, since most of the light beams have a large incident angle with respect to the inclined surface 11 b, they are totally reflected by the inclined surface 11 b and travel in the direction of the opposite back surface portion 8 away from the concentric convex ridge 11. In particular, a light beam having a small refraction angle γ is also totally reflected by the back surface portion 8 because the inclination angle (angle θ2) of the inclined surface 11b is small, and the emitted light is obtained from the surface portion 7 or the like largely separated from the concentric convex ridge 11. be able to.

In addition, here, a description has been given of the case where the concentric concave ridge 10 is provided on the back surface portion 8 of the light guide plate 2 and the case where the concentric convex ridge 11 is provided on the front surface portion 7. 7 is the same as when the concentric concave ridge 10 is provided on the back surface 8 and when the concentric convex ridge 11 is provided on the back surface portion 8, the ray trajectory is the same. The ideal outgoing light is obtained by changing the angle θ and the angle θ2 of the inclined surface 10a and the inclined surface 11b of the convex ridge 11.
Further, the light beam directly transmitted and refracted from the inclined surface 10a and the inclined surface 11b on the back surface portion 8 of the light guide plate 2 is reflected by the reflective reflector, the case 14 and the like, and returned to the light guide plate 2 again. .

  Here, the cross section of the shape of the concentric concave ridge 10 or the concentric convex ridge 11 that is concentrically continuous or discontinuous with the opening 5 is a triangular or concentric dot-shaped triangular prism concave shape or a triangular prism convex minute shape. Although the description has been made with respect to the optical deflecting element 12, the shape may be a trapezoid or the like, and it is only necessary to have the inclined surface 10a in the direction of the opening 5.

  Further, as shown in FIG. 1, a plurality of minute amounts are formed on the front surface portion 7 and the back surface portion 8 opposite to the side where the concentric concave ridges 10 and / or the concentric convex ridges 11 are provided on the front surface portion 7 and the back surface portion 8 of the light guide plate 2. An optical deflection element 12 can also be provided.

In particular, if the back surface 8 is provided with a concentric concave ridge 10 or a concentric minute light deflecting element 12 such as a dot-like triangular prism concave shape, and a plurality of minute light deflecting elements 12 are provided on the surface portion 7 on the opposite side, The critical angle α can be broken by refracting light rays close to the critical angle α. In addition, the light amount reaching the surface portion 7 by the concentric concave ridges 10 can be adjusted by condensing or diffusing the light by condensing action or diffusing action by refraction.
Furthermore, even when the light beam directly traveling in the direction of the surface portion 7 does not reach the critical angle α, the micro light deflecting element 12 can break the critical angle α to be emitted to the outside, and light existing in the light guide plate 2 can be emitted. More light can be emitted from the emission surface, and a brighter emission surface can be obtained.

  Although not shown, the dot-shaped minute light deflection element 12 has a convex shape or a concave shape such as a part of a sphere and an elliptical sphere, and a triangular pyramid, a cone, a quadrangular pyramid, a triangular prism, a quadrangular prism, and a cylinder.

Next, the flat illumination device 1b shown in FIG. 2 includes a light guide plate 2b in which an opening 5 is provided at one end portion 4, a light source 9 provided in the opening 5, and a back surface portion of the light guide plate 2b. 8 and a case 14 having reflectivity.
The light guide plate 2b shown in FIG. 2 is positioned on the opposite side of the four side portions 3, the four end portions 4b to which the side portions 3 are connected, the surface portion 7 that emits light, and the surface portion 7. It consists of a back surface portion 8. In addition, an incident portion of a substantially circular opening 5 that guides light from the light source 9 is provided inside only one end 4 of the four ends 4b of the light guide plate 2b.
Here, the opening 5 is a through hole. However, the concave opening 5 may be provided on the back surface 8 side so as to be opposite to the emission surface.

Here, concentric concave ridges 10 and concentric convex ridges 11 are provided on the back surface portion 8, and nothing is provided on the front surface portion 7 and is a mirror surface.
In particular, in FIG. 2, the front surface portion 7 and the back surface portion 8 in the outer side direction of the opening 5 are mirror surfaces without providing anything, and thus the light is emitted from the front surface portion 7 and the back surface portion 8 in the outer direction of the opening 5. The light directed toward the front surface portion 7 and the back surface portion 8 in the outer direction of the opening 5 can be kept in the light guide plate 2b without leaking to the outside, and the light is used for light emitted from the light emission surface that needs it. can do.

Further, as described with reference to FIG. 1, the end portion 4 has an outer side surface portion 3 corresponding to the substantially circular opening portion 5 at a positive multiple of the opening portion 5 similar to the shape of the opening portion 5. Make the size.
Further, as described with reference to FIG. 1, a fine convex shape and / or concave shape processing is applied to a portion outside the side surface portion 3 corresponding to the opening 5 of the end portion 4, although not shown. Furthermore, although not shown in the drawing, the inner wall connecting the front surface portion 7 and the back surface portion 8 of the opening 5 is subjected to fine convex or / and concave processing.
In addition, since an operation and an effect overlap with the description in FIG. 1, they are omitted here as well as the embodiment.

  In this way, since the light guide plate 2b has the substantially circular opening 5 that enters the light inside one end portion 4, the light can be prevented from leaking outside the light guide plate 2b, and the light can be maximized. It can be used effectively, and high-intensity outgoing light that is uniform and free from spots can be obtained. In addition, since the end 4 has an outer side corresponding to the substantially circular opening 5 having a size that is a multiple of the opening 5 and a substantially shape of the opening 5, the substantially right end 4 b outside the side surface 3. The light directed toward the side surface portion 3 can be efficiently reflected without hitting the plane, and the generation of bright lines in the central direction of the light guide plate 2b can be prevented.

Further, the light guide plate 2c shown in FIG. 3 is provided with an end portion 4a where the side surface portions 3 are connected to each other outside the side surface portion 3, and the outside of the end portion 4a is a multiple of the opening 5 in size. This is a substantially opening 5 type shape.
The end 4a may be substantially concentric with the opening 5 or may have an elliptical shape slightly different from the end 4a. What is necessary is just to make it reflect efficiently in the internal direction of the light-guide plate 2c so that it may avoid.

Further, as described with reference to FIG. 1, a fine convex shape and / or concave shape processing is applied to a portion outside the side surface portion 3 corresponding to the opening portion 5 of the end portion 4a, though not shown. Furthermore, although not shown in the drawing, the inner wall connecting the front surface portion 7 and the back surface portion 8 of the opening 5 is subjected to fine convex or / and concave processing.
Similarly, concentric concave ridges 10 and / or concentric convex ridges 11 are provided on the front surface portion 7 and the rear surface portion 8 of the light guide plate 2c as shown in FIG. A plurality of minute light deflection elements 12 are provided.
In addition, since an operation and an effect overlap with the description in FIG. 1, they are omitted here as well as the embodiment.
Further, like FIG. 1 and FIG. 2, the opening 5 is also formed as a through hole here, but the concave opening 5 may be provided on the back surface 8 side so as to be opposite to the emission surface.
Moreover, although the opening part 5 was provided in the edge part 4a of four corners here, it may be two places or two places of the both ends 4a, or one place.

  As described above, since the end portion 4a is provided outside the side surface portion 3, the substantially perpendicular end portion 4 outside the side surface portion 3 can be eliminated and a large area of light emission from the light guide plate 2c can be secured. . Further, the light directed toward the outer side of the end portion 4a can be efficiently reflected without hitting a flat surface, and generation of bright lines in the central direction of the light guide plate 2c can be prevented. Furthermore, it is possible to prevent the prism body, the liquid crystal panel, and the like provided above the light guide plate 2c of the present invention from being affected by heat from the light source.

Further, the light guide plate 2d shown in FIG. 4 is provided with an end portion 4a provided outside the side surface portion 3b, and the side surface portion 3b is connected with an inclination from each end portion 4a having a substantially opening 5 shape and adjacent to each other. The distances between the end portions 4a and 3c at the same distance are connected with different inclination directions, and the distance between the side surface portions 3b at which the intermediate portions 3c face each other is the shortest.
The end 4a may be substantially concentric with the opening 5 or may have an elliptical shape slightly different from the end 4a. In order to avoid this, the light may be efficiently reflected in the inner direction of the light guide plate 2d.

In addition, as described with reference to FIG. 1, a fine convex or / and concave process is performed on the outer portion of the side surface 3 b corresponding to the opening 5 of the end 4 a, although not shown. Further, although not shown, the inner wall connecting the front surface portion 7 and the back surface portion 8 of the opening 5 is processed with a fine convex shape and / or concave shape.
Similarly, concentric concave ridges 10 and / or concentric convex ridges 11 are provided on the front surface portion 7 and the rear surface portion 8 of the light guide plate 2d as shown in FIG. A plurality of minute light deflection elements 12 are provided.

In addition, since an operation and an effect overlap with the description in FIG. 1, they are omitted here as well as the embodiment.
Further, like FIG. 1 and FIG. 2, the opening 5 is also formed as a through hole here, but the concave opening 5 may be provided on the back surface 8 side so as to be opposite to the emission surface.
Moreover, although the opening part 5 was provided in the edge part 4a of four corners here, it may be two places or two places of the both ends 4a, or one place.

  As described above, the side surface portion 3b can be used to guide the incident light from each opening portion 5 into the light guide plate 2d, and the side surface portion 3b connected from each substantially opening portion 5 shape is formed from the opening portion 5. , The light utilization rate is good, the light can reach a position away from the light source 9, and bright outgoing light without spots can be obtained.

Further, the light guide plate 2e shown in FIG. 5 is provided with one end portion 4a that connects the side surface portions 3b to the outside of the side surface portion 3b, and the side surface portion 3b from the end portion 4a having a substantially opening 5 shape to the other side. It has an inclination to the end 4b.
Further, the outer side of the end portion 4a is a substantially opening portion 5 type shape that is a multiple of the opening portion 5, and the other end portion 4b is not a substantially opening portion 5 shape but has a general corner end. The side surface portions 3 connecting the end portions 4b are straight and have no inclination.

Here, the light trajectory of the light guide plate 2e will be described.
Although not shown, the light from the light source 9 that emits light in a 360-degree radial manner is processed on the inner wall of the opening 5, but a fine convex shape or a fine concave shape is applied to spread the light incident from the opening 5. The light travels in the outward direction of the end 4. In addition, although not shown in the drawing, the outer portion corresponding to the opening 5 of the end portion 4 is processed into a fine convex shape or a fine concave shape, and the light beam Lr totally reflected here is inside the light guide plate 2e. The light from the light source 9 can be used without waste, more light can be introduced into the light guide plate 2e, and bright outgoing light can be obtained. Further, since the light diffuses when the light source 9 of different emission color is provided in the opening 5 and proceeds toward the inside of the light guide plate 2e, different emission colors can be mixed better.
Further, the light incident from the opening 5 diffuses with a spread, and part of the light travels in the inner direction of the light guide plate 2e as it is. In particular, the light beam Lss uses the side surface portion 3b to guide the incident light from the substantially opening portion 5a shaped end portion 4a into the light guide plate 2e by the inclined side surface portion 3b, and the side surface portion facing the opening portion 5 You can go in three directions. Thereby, the utilization factor of light is good and light can reach a position away from the light source 9, and bright emission light can be obtained.

Similar to FIG. 3, the end 4 may have a substantially concentric shape with the opening 5, or may have an elliptical shape slightly different from the end 4, and the light beam traveling in the outward direction of the end 4, What is necessary is just to make it reflect efficiently in the internal direction of the light-guide plate 2e so that the opening part 5 may be avoided.
Further, as in FIG. 3, the opening 5 is also used as a through hole here, but the concave opening 5 may be provided on the back surface 8 side so as to be opposite to the emission surface.
Similarly, concentric concave ridges 10 and / or concentric convex ridges 11 are provided on the front surface portion 7 and the rear surface portion 8 of the light guide plate 2e as shown in FIG. A plurality of minute light deflection elements 12 are provided.
In addition, since an operation and an effect overlap with the description in FIG. 1, they are omitted here as well as the embodiment.

  The light source 9 emits light radially at 360 °. Although not shown, a semiconductor light emitting element is mounted on a mounting surface on a lead frame or a substrate, and a transparent resin is disposed in the light emitting direction from the semiconductor light emitting element. Etc. are molded by the above method. More specifically, the mold has a cylindrical shape as a whole, and has a shape in which the position facing the semiconductor light emitting element at the bottom is cut into a conical shape in the opposite direction, and emits light radially. Further, as the mold, the lower portion has a cylindrical shape, the upper position facing the semiconductor light emitting element at the bottom is a funnel shape having a radial curve outside the cylindrical shape, and the upper position is a conical shape with the opposite direction In other words, the light may be emitted radially in the circumferential direction from the tip of the funnel shape by repeating total reflection with a conical conical surface and a curved curved surface. Further, the mold as a whole has a substantially conical shape, the shape facing the semiconductor light emitting element is cut into a conical shape in the opposite direction, totally reflected by the conical conical surface, and slightly downward The light may be emitted radially with an inclination.

The light emitting body of the light source 9 is a semiconductor light emitting element, and is composed of an LED, a laser, or the like, and RGB (red, green, blue) monochromatic light is provided in the opening 5 or RGB (red light emission, green light emission, A plurality of semiconductor light emitting elements composed of blue light emission) may be combined into one light source 9.
In particular, when the light source 9 requires high luminance, a high-intensity light-emitting element of a quaternary compound or a compound such as an InGaAlP-based, InGaAlN-based, or InGaN-based compound is used.

  Further, white light may be obtained using a semiconductor light emitting element and a wavelength conversion material. For example, a wavelength conversion material (YAG system) that is excited by blue light emitted from an InGaAlN-based semiconductor light-emitting element and emits light in yellow, orange, or the like is provided. The light source 9 may be a light source 9 in which the emission color mixed with the emission color in orange or the like becomes white.

As described above, the emitted light emitted from the semiconductor light emitting element in the thickness direction of the front surface portion 7 and the back surface portion 8 is emitted in a 360 ° radial manner with a reflection portion in front of the emission direction, and 360 ° in the direction of the side surface portion 3. Since it is deflected, it can be emitted in all horizontal directions without directivity.
For this reason, it is possible to avoid the reflection of strong light from the light source 9 itself, and it is possible to obtain outgoing light with good appearance.

  The case 14 or the reflector 14 is made of a thermoplastic resin mixed with a white material such as titanium oxide, or a metal such as aluminum is vapor-deposited on the thermoplastic resin. The light from the cover light source 9 is reflected or irregularly reflected by the light guide plates 2, 2 b, 2 c, 2 d, and 2 e, and is incident on the light guide plates 2, 2 b, 2 c, 2 d, and 2 e again. All the light from the light source 9 is emitted from the surface portion 7.

  Further, when the reflecting surface of the case 14 or the reflector 14 is provided with an uneven shape or a prism shape, light of the three primary colors such as RGB from the light source 9 is reflected by the prism surface to reflect the light guide plates 2, 2b, 2c, 2d and 2e can be mixed, and the efficiency of converting light from the light source 9 into light emitted from the light guide plates 2, 2b, 2c, 2d and 2e can be improved without wasting it.

  As described above, the light guide plate 2 and the flat illumination device 1 of the present invention are provided with the substantially circular opening 5 inside the at least one end portion 4 of the light guide plate 2, and the outside of the side surface portion 3 outside thereof is the opening. 5, an end 4 having a substantially opening 5 shape that is a multiple of the size of the opening 5 is provided outside the side surface 3, and has a substantially side surface similar to the opening 5. Fine convex or concave processing is performed on the outer side of the portion 3 or the outer shape of the substantially opening portion 5, or fine convex or concave processing is performed on the inner wall connecting the front surface portion 7 and the back surface portion 8 of the opening portion 5. Further, the side surface portion 3 is connected with an inclination from the end portion 4 of the substantially opening 5 type shape, or the position 3c of the intermediate portion of the side surface portion 3 having a plurality of inclinations is opposed to each other. The distance is the shortest, and concentric concave ridges 10 that are continuous or discontinuous concentrically with the opening 5 on the front surface 7 and the back surface 8 A light guide plate 2 provided with a core-like convex ridge 11 or a concentric dot-shaped minute light deflection element 12, and light emitted in the thickness direction of the front surface portion 7 and the back surface portion 8 is provided with a reflection portion in front of the emission direction. A light source 9 that deflects 360 ° in the direction of the side surface is provided in the opening 5 to effectively use the light from the light source 9 without waste, to obtain high-luminance outgoing light, and to avoid the occurrence of dark and bright parts The light guide plate 2 and the flat illumination device 1 can avoid the reflection of strong light from the light source.

  Suitable for backlights such as small liquid crystal display devices to backlights for large liquid crystal display devices, etc., and in particular, because it is possible to obtain emitted light with high brightness and no luminance spots or color temperature spots, for example, from mobile products to liquid crystal televisions, etc. It is possible to provide a light guide plate and a flat illumination device ranging from general-purpose products to special applications.

1 is a schematic perspective view of a flat illumination device according to the present invention. 1 is a schematic perspective view of a flat illumination device according to the present invention. It is a schematic front view of the concept of the light guide plate according to the present invention. It is a schematic front view of the concept of the light guide plate according to the present invention. It is a schematic front view of the light-guide plate which concerns on this invention, and a locus diagram of light. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram. It is a schematic sectional view of the light guide plate according to the present invention and a light locus diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1b Planar illuminating device 2,2b, 2c, 2d, 2e Light guide plate 3,3b Side surface part 3c Intermediate position 4,4a, 4b End part 5 Opening part 7 Front surface part 8 Back surface part 9 Light source 10 Concentric concave ridge 10a, 10b Inclined surface 11 Concentric convex ridges 11a, 11b Inclined surface 12 Small optical deflecting element 14 Case or reflector L0, Lbr, Lrr, L00 ray L0mx, L0mi, Lrmx, Lrmi ray L02, L12, L22 rays L01, L03, L11 , L13, L21, L23 rays L0L1, LrL1 rays L0L3, LrL3 rays L0L2, LrL2 rays L00, L0m, Lmp rays Lp1, L0r, L0rr rays L011, L110 rays L012, L013, L120, L0r rays LL0r L0r , L0r22 ray Lr Lss rays γ refraction angle n the refractive index α critical angle θ1 apex angle theta, .theta.2 angle

Claims (13)

In a light guide plate having a front surface part or / and a back surface part that emits light, and a side surface part that intersects with the front surface part and the back surface part,
A light guide plate having a substantially circular opening through which light enters at least one end. 2. The light guide plate according to claim 1, wherein the end portion has an outer side surface corresponding to the opening and has a size that is a multiple of the opening and an approximate shape of the opening. 2. The light guide plate according to claim 1, wherein the end portion is provided outside the side surface portion and has a substantially opening shape having a size that is a multiple of the opening portion. The light guide plate according to claim 3, wherein the side surface portion is connected with an inclination from the end portion of the substantially opening shape. The side surface portion is connected with an inclination from each of the end portions of the substantially opening shape, and the distance between the side surface portions where the intermediate portions of the adjacent end portions face each other is the shortest distance. The light guide plate according to claim 3. 4. The light guide plate according to claim 3, wherein the end portion is processed with a fine convex shape and / or a concave shape on the outside of the side surface portion corresponding to the opening portion or on the outside of the substantially opening shape. 5. 2. The light guide plate according to claim 1, wherein the opening has a fine convex and / or concave shape formed on an inner wall connecting the front surface portion and the back surface portion. The front surface portion and / or the back surface portion is provided with a concentric concave ridge or / and a concentric convex ridge or concentric dot-shaped micro light deflection element concentrically continuous or discontinuous with the opening. The light guide plate according to claim 1. The front surface portion and the back surface portion are provided with a plurality of minute light deflection elements on the front surface portion or the back surface portion opposite to the side on which the concentric concave ridge or / and the concentric convex ridge is provided. The light guide plate according to claim 8. The light guide plate according to claim 1, wherein the end portion is a mirror surface without providing anything on the front surface portion and the back surface portion in the outer direction of the opening. The concentric concave ridge and the concentric convex ridge have a vertex angle of 45 ° to 174 ° and have an inclined surface in the opening direction and a virtual horizontal plane parallel to the front surface portion or the back surface portion. The light guide plate according to claim 8, wherein the angle is in a range of 3 ° to 67.5 °. A light guide plate having a front surface part or / and a back surface part for emitting light, a side surface part intersecting with the front surface part and the back surface part, and having a substantially circular opening inside at least one end part;
A light source that emits light radially at 360 °;
A reflector having reflectivity that covers the surface opposite to the surface from which light is emitted from the light guide plate and the side surface portion;
A flat illumination device, wherein the light source is provided in the opening. 13. The flat surface according to claim 12, wherein the light source includes a reflecting portion in front of the emitting direction and deflects light emitted in the thickness direction of the front surface portion and the back surface portion by 360 ° toward the side surface portion. Lighting device.

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