JP2006310031A - Light guide plate and flat lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively use light refracted downward from a light-incident part. <P>SOLUTION: This flat lighting system 1 is equipped with a light source 9, a light guide plate 2, which is composed of a light-incident part 3 to guide light from the light source 9, a light-emitting surface part 4 to emit light to the outside, and a side part 6 almost perpendicularly connecting with these light-incident part 3 and light-emitting surface part 4, and in which a plurality of mirror finished parts 8 totally reflecting light entered into the inside from the light-incident part 3 in the direction almost perpendicular to the light-incident part 3, and light-reflecting parts 7 having those positions in contact with continuously changing normal lines as mirror finished surfaces which totally reflect a part of the light made incident on the inside from the light-incident part 3 while having an angle of refraction close to its maximum value in the second direction, substantially in parallel with the light-incident part 3 are provided on the facing side 5 facing the light-emitting surface 4, a reflector 11 to reflect light from the side part 6 and the facing side 5 of the light guide plate 2, and a case 12 to house at least the light source 9 and the reflector 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a mirror surface portion that totally reflects light incident on the inside from the incident portion with respect to a first direction substantially perpendicular to the incident portion, and light in the vicinity of the maximum value of the refraction angle incident on the inside from the incident portion. A plurality of light reflecting portions having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion are provided on the front surface portion and the back surface portion. A light guide plate that can be condensed and emitted in the second direction when emitted to the outside, and can be incident in a direction having a spread with respect to the second direction inside by the light reflecting portion; The present invention relates to a flat illumination device using the light guide plate and a reflector.

  As a conventional light guide plate, a plurality of diffusing prisms having a substantially isosceles cross section with a ridge line in a direction perpendicular to the axis of the tubular light source on the surface and a vertex angle ranging from 65 ° to 85 ° are formed. Things are known.

Further, as a conventional light guide plate, a prism having a light deflection pattern with a prism ridge parallel to the incident portion on the back surface, a prism with a light condensing pattern perpendicular to the incident portion on the surface portion, A light source having a cylindrical lens-shaped light condensing pattern in the vicinity of the light deflection pattern is known, and a surface light source device using this light guide plate is also known.
Japanese Patent Laid-Open No. 11-024584 JP 09-1113730 A

By the way, in this type of light guide plate, the light incident from the incident end face portion travels in the light guide plate in a range where the refraction angle γ satisfies the expression 0 ≦ | γ | ≦ Sin ⁻¹ (1 / n). For example, since the refractive index n of acrylic resin, which is a resin material used for a general light guide plate, is about n = 1.49, the incident light is in the range of the refraction angle γ = ± 42 °.

  Further, the light incident on the light guide plate within the range of the refraction angle γ = ± 42 ° is expressed by the equation Sin α = (1 / n) at the boundary surface between the light guide plate and the air layer (refractive index is n = 1). Can represent the critical angle. For example, since the refractive index n of acrylic resin, which is a resin material used for general light guide plates, is about n = 1.49, the critical angle α is about α = 42 °.

  Therefore, if there are no projections or depressions that deflect the light beam on the front or back surface of the light guide plate, or if the critical angle α is not exceeded, all the light in the light guide plate is totally reflected on the front and back surfaces, and the incident end face It moves away from the part and proceeds in the direction opposite to the incident end face part.

  In addition, when the entire light guide plate has a wedge shape (generally, the front surface is flat and the back surface side is tapered), the light beam reflected by the back surface is reflected by the taper angle. Is deflected and proceeds to the surface. Then, when the light beam having an angle that breaks the critical angle reaches the surface portion while repeating this total reflection, the incident angle becomes an angle that breaks the critical angle α, and is emitted from the surface portion to the outside (taper leak).

  When verified based on the logic for the light guide plate as described above, the cross-section is substantially isosceles triangle shape with a ridge line in the direction perpendicular to the axis of the tubular light source on the conventional surface described above, and the apex angle is 65 °. In the light guide plate in which a plurality of diffusion prisms in the range of ˜85 ° are formed, the light (light in the range of refraction angle γ = + 42 °) directed toward the surface portion of the light incident from the incident portion of the light guide plate has a cross section. It works effectively for a diffusing prism with an isosceles triangle shape with an apex angle in the range of 65 ° to 85 ° (the luminance distribution of the emitted light is shifted in the direction of 120 °), but toward the back surface. There is a problem that light (light having a refraction angle γ = −42 °) is not effectively used.

  Further, in the case of a light guide plate in which the ridge of the prism of the conventional light deflection pattern is provided in parallel with the incident portion, the light beam from the incident portion to the opposite side of the incident portion is always transmitted by the light deflection pattern in front of the incident portion side. There is a problem that prevents it.

  In addition, in the case of a light guide plate provided with a cylindrical lens-shaped light condensing pattern having a focal point near the light deflection pattern, the light deflection pattern certainly places the light in the light condensing pattern into the light guide plate. However, there is a problem that a luminance spot that recognizes a different brightness from the other along the arrangement of the light converging pattern occurs.

(Object of invention)
An object of the present invention is to provide a mirror surface portion that totally reflects light incident from the light source into the light guide plate in a first direction substantially perpendicular to the incident portion, and a vicinity of the maximum value of the refraction angle incident from the incident portion to the inside. By providing a plurality of light reflecting portions on the front surface, the back surface, etc. with the mirror surface at the position in contact with the continuously changing normal that is totally reflected in the second direction substantially parallel to the incident portion in the light When the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, the light is condensed and emitted in the second direction, and the light from the outside of the light guide plate to the inside of the light guide plate by the light reflecting portion. A light guide plate that can be incident in a direction that is wide with respect to the direction of 2 and that can totally advance light from the inside of the light guide plate by the light reflecting portion and condense the light in the direction of the exit surface. It is to provide.

  In addition, a light guide plate that can effectively use the light refracted downward from the incident portion described above, a reflector that reflects light from a side surface portion and a front surface portion or a back surface portion of the light guide plate, and the light source and the light guide plate. And a case for housing the reflector, the light collected by the reflector in the second direction is reflected on the opposite exit surface of the light guide plate, and the reflected light is guided by the light reflector. An object of the present invention is to provide a flat illumination device capable of entering a light plate in a direction having a spread with respect to the second direction.

  The light guide plate according to claim 1 of the present invention includes a mirror surface portion that totally reflects light incident from the incident portion into the light guide plate with respect to the first direction substantially perpendicular to the incident portion, and the incident portion into the light guide plate. A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the incident refraction angle. It is characterized in that a plurality of surfaces are provided on the opposing surface.

  The light guide plate according to claim 1 includes a mirror surface portion that totally reflects light incident from the incident portion into the light guide plate in a first direction substantially perpendicular to the incident portion, and refraction incident from the incident portion into the light guide plate. A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the angle is opposed to the emission surface portion. Since a plurality of light beams are provided on the opposing surface, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion. Moreover, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it can be condensed and emitted in the second direction. Moreover, the light from the outside of the light guide plate can be incident on the inside of the light guide plate in the direction having a spread with respect to the second direction by the light reflecting portion.

Further, the light guide plate according to claim 2 is provided with a supercritical portion that breaks a critical angle of light existing in the light guide plate on an emission surface portion that emits light incident on the light guide plate from the incident portion,
A mirror surface portion that totally reflects light incident on the light guide plate from the incident portion with respect to the first direction substantially perpendicular to the incident portion, and light in the vicinity of the maximum refraction angle incident on the light guide plate from the incident portion. And a plurality of light reflecting portions having a mirror surface at a position in contact with a continuously changing normal line that is totally reflected in a second direction substantially parallel to the incident portion. To do.

The light guide plate according to claim 2 is provided with a supercritical portion that breaks a critical angle of light existing in the light guide plate on an output surface portion that emits light incident on the light guide plate from the incident portion,
A mirror surface portion that totally reflects light incident on the light guide plate from the incident portion with respect to the first direction substantially perpendicular to the incident portion, and light in the vicinity of the maximum refraction angle incident on the light guide plate from the incident portion. The light guide plate is provided with a plurality of light reflecting portions having a mirror surface at a position in contact with a continuously changing normal line that is totally reflected in a second direction substantially parallel to the incident portion. Light in the vicinity of the maximum value of the refraction angle incident inside can be totally reflected by the light reflecting portion. In addition, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, the light is condensed with respect to the second direction and the light is condensed in the direction of the emission surface portion. Light can enter the light guide plate in a direction having a spread with respect to the second direction by the light reflecting portion.
In addition, light near the maximum value of the refraction angle incident in the light guide plate from the incident portion reaching the vicinity of the output surface portion or light incident in the direction in which the light reflection plate spreads out can be emitted from the output surface portion. it can.

  Furthermore, the light guide plate according to claim 3 has a mirror surface portion that totally reflects the light incident inside from the incident portion with respect to the first direction substantially perpendicular to the incident portion, and a refraction angle incident inside from the incident portion. The light reflecting portion having a mirror surface at a position in contact with the continuously changing normal that totally reflects in the second direction parallel to the incident portion in the light near the maximum value is 6 ° or less with respect to the incident portion. A plurality of them are provided at least on the exit surface portion or the opposing surface with an inclination deviation.

The light guide plate according to claim 3 includes a mirror surface part that totally reflects light incident inside from the incident part with respect to a first direction substantially perpendicular to the incident part, and a maximum value of the refraction angle incident inside from the incident part. The light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in the second direction parallel to the incident portion in the vicinity of the light is inclined to 6 ° or less with respect to the incident portion. Since a plurality of deviations are provided at least on the emission surface portion or the opposite surface, when the light from the inside of the light guide plate is emitted to the outside by the light reflection portion with an overall deviation of 6 ° or less, the second direction is used. It can be condensed and emitted. In addition, light from the outside of the light guide plate can be incident on the light guide plate in a direction that is wider than the second direction by the light reflecting portion.
Furthermore, the light from the inside of the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.

  The light guide plate according to a fourth aspect is characterized in that the light reflecting portion is provided continuously or in parallel with respect to the second direction.

  In the light guide plate according to the fourth aspect, since the light reflecting portion is connected or juxtaposed with respect to the second direction, the second direction when light from the inside of the light guide plate is emitted to the outside by the light reflecting portion. In contrast, the light condensed and emitted can be emitted continuously or discontinuously. Moreover, the light from the outside of the light guide plate can be continuously or discontinuously incident in the light guide plate in the direction in which the light spreads from the second direction with respect to the second direction.

  Furthermore, the light guide plate according to claim 5 is characterized in that the crossing angle between two tangents of the maximum width of the light reflecting portion extending and intersecting is 50 ° to 90 °.

  The light guide plate according to the fifth aspect of the present invention can be configured with a small number of convex portions with respect to a large curvature radius because the crossing angle between the two tangents of the maximum width of the light reflecting portion extending and intersecting is 50 ° to 90 °.

Moreover, the flat illumination device according to claim 6 includes a light source,
An incident portion that guides light from the light source, an emission surface portion that emits the light to the outside, and a side surface portion that is connected to the incidence portion and the emission surface portion at a substantially right angle, and incident light from the incident portion to the inside A mirror surface part that totally reflects in a first direction perpendicular to the first part, and total reflection in a second direction that is substantially parallel to the incident part in light near the maximum value of the refraction angle incident from the incident part. A light guide plate provided with a plurality of light reflection portions on the opposite surface facing the emission surface portion, with a mirror surface at a position in contact with the continuously changing normal line;
A reflector that reflects light from the side surface and the opposing surface of the light guide plate;
At least the light source, the light guide plate, and a case for housing the reflector are provided.

A flat illumination device according to claim 6 includes a light source,
An incident portion that guides light from the light source, an emission surface portion that emits the light to the outside, and a side surface portion that is connected to the incidence portion and the emission surface portion at a substantially right angle, and incident light from the incident portion to the inside A mirror surface part that totally reflects in a first direction perpendicular to the first part, and total reflection in a second direction that is substantially parallel to the incident part in light near the maximum value of the refraction angle incident from the incident part. A light guide plate provided with a plurality of light reflection portions on the opposite surface facing the emission surface portion, with a mirror surface at a position in contact with the continuously changing normal line;
A reflector that reflects light from the side surface and the opposing surface of the light guide plate;
Since at least the light source, the light guide plate, and the case for housing the reflector are provided, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it is condensed and emitted in the second direction. The reflected light can be reflected by the reflector to the anti-emission part of the light guide plate, and at least these reflected lights can be incident in the light guide plate in a direction that is wider than the second direction by the light reflection part.
In particular, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.

Furthermore, the flat illumination device according to claim 7 includes a light source,
An incident portion that guides light from the light source, an emission surface portion that emits the light to the outside, and a side surface portion that is connected to the incidence portion and the emission surface portion at a substantially right angle, and emits light incident inside from the incident portion. A supercritical portion that breaks the critical angle of light existing inside is provided on the exit surface portion, a mirror surface portion that totally reflects the light incident inside from the entrance portion in a first direction substantially perpendicular to the entrance portion, and the entrance portion A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the refraction angle incident on the inside from A plurality of light guide plates provided on the opposing surface facing the emission surface portion,
A reflector that reflects light from the side surface and the opposing surface of the light guide plate;
At least the light source, the light guide plate, and a case for housing the reflector are provided.

The flat illumination device according to claim 7 includes a light source,
An incident portion that guides light from the light source, an emission surface portion that emits the light to the outside, and a side surface portion that is connected to the incidence portion and the emission surface portion at a substantially right angle, and emits light incident inside from the incident portion. A supercritical portion that breaks the critical angle of light existing inside is provided on the exit surface portion, a mirror surface portion that totally reflects the light incident inside from the entrance portion in a first direction substantially perpendicular to the entrance portion, and the entrance portion A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the refraction angle incident on the inside from A plurality of light guide plates provided on the opposing surface facing the emission surface portion,
A reflector that reflects light from the side surface and the opposing surface of the light guide plate;
Since at least the light source, the light guide plate, and the case for housing the reflector are provided, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it is condensed and emitted in the second direction. The reflected light can be reflected by the reflector to the light-exiting surface portion of the light guide plate, and at least the reflected light can be incident on the light guide plate in a direction that is wider than the second direction by the light reflection portion.
In particular, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.
In addition, light near the maximum value of the refraction angle incident in the light guide plate from the incident portion reaching the vicinity of the output surface portion or light incident in the direction in which the light reflection plate spreads out can be emitted from the output surface portion. it can.

  The flat illumination device according to claim 8 is characterized in that the light guide plate is placed with an inclination of 6 ° or less with respect to the light source parallel to the incident portion.

  In the flat illumination device according to the eighth aspect, since the light guide plate is placed with an inclination of 6 ° or less with respect to the light source parallel to the incident portion, the light emitted from the light exit surface portion of the light guide plate and the upper portion of the light guide plate When a prism sheet, a liquid crystal display device, or the like is placed on the liquid crystal display device, it is possible to prevent the occurrence of moire because the pitch of the light reflecting portions does not match the phase of the prism sheet or the pitch of the liquid crystal pixels of the liquid crystal display device.

Furthermore, the flat illumination device according to claim 9 includes a light source,
An incident portion that guides light from the light source, and a front surface portion, a back surface portion, and a side surface portion that are connected at a substantially right angle to the incident portion, and the light incident on the inside from the incident portion with respect to the first direction substantially perpendicular to the incident portion. And a mirror surface portion that totally reflects, and a continuously changing normal line that totally reflects in a second direction parallel to the incident portion in the light near the maximum value of the refraction angle incident inside from the incident portion. A light guide plate provided with a plurality of light reflection portions whose positions are mirror surfaces at least on the front surface portion or the back surface portion with an inclination shift of 6 ° or less with respect to the incident portion;
A reflector that reflects light from the side surface and the front or back surface of the light guide plate;
At least the light source, the light guide plate, and a case for housing the reflector are provided.

A flat illumination device according to claim 9 includes a light source,
An incident portion that guides light from the light source, and a front surface portion, a back surface portion, and a side surface portion that are connected at a substantially right angle to the incident portion, and the light incident on the inside from the incident portion with respect to the first direction substantially perpendicular to the incident portion. And a mirror surface portion that totally reflects, and a continuously changing normal line that totally reflects in a second direction parallel to the incident portion in the light near the maximum value of the refraction angle incident inside from the incident portion. A light guide plate provided with a plurality of light reflection portions whose positions are mirror surfaces at least on the front surface portion or the back surface portion with an inclination shift of 6 ° or less with respect to the incident portion;
A reflector that reflects light from the side surface and the front or back surface of the light guide plate;
Since at least the light source, the light guide plate, and the case for housing the reflector are provided, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it is condensed and emitted in the second direction. The reflected light can be reflected by the reflector to the light-exiting surface portion of the light guide plate, and at least the reflected light can be incident on the light guide plate in a direction that is wider than the second direction by the light reflection portion.
In particular, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.
Further, since the inclination is shifted to 6 ° or less with respect to the incident portion, the light reflected from the light emitted from the light exit surface portion of the light guide plate and the prism sheet, the liquid crystal display device, or the like is placed on the light guide plate. The occurrence of moire can be prevented because the pitch of the prism does not coincide with the pitch of the prism sheet or the pitch of the liquid crystal pixels of the liquid crystal display device.

  As described above, the light guide plate according to claim 1 includes the mirror surface portion that totally reflects the light incident from the incident portion into the light guide plate in the first direction substantially perpendicular to the incident portion, and the light guide plate from the incident portion. A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the refraction angle incident inside Since a plurality of light beams are provided on the facing surface that faces the light emitting surface portion, the light near the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion. Moreover, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, the light is condensed and emitted in the second direction, and the light from the outside of the light guide plate to the inside of the light guide plate by the light reflecting portion. It can enter in the direction which has a breadth with respect to the 2nd direction. Therefore, the light refracted downward from the incident portion of the light guide plate can be used effectively, and high-luminance outgoing light can be obtained.

Further, the light guide plate according to claim 2 is provided with a supercritical portion that breaks a critical angle of light existing in the light guide plate on an emission surface portion that emits light incident on the light guide plate from the incident portion,
A mirror surface portion that totally reflects light incident on the light guide plate from the incident portion with respect to the first direction substantially perpendicular to the incident portion, and light in the vicinity of the maximum refraction angle incident on the light guide plate from the incident portion. The light guide plate is provided with a plurality of light reflecting portions having a mirror surface at a position in contact with a continuously changing normal line that is totally reflected in a second direction substantially parallel to the incident portion. Light in the vicinity of the maximum value of the refraction angle incident inside can be totally reflected by the light reflecting portion. In addition, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, the light is condensed with respect to the second direction and the light is condensed in the direction of the exit surface portion, and the light from the outside of the light guide plate is advanced. Can be incident on the inside of the light guide plate in a direction broadening with respect to the second direction by the light reflecting portion.
In addition, light near the maximum value of the refraction angle incident in the light guide plate from the incident portion reaching the vicinity of the output surface portion or light incident in the direction in which the light reflection plate spreads out can be emitted from the output surface portion. it can. Therefore, the light refracted downward from the incident portion of the light guide plate can be effectively used, and uniform and high-luminance outgoing light can be obtained.

Furthermore, the light guide plate according to claim 3 has a mirror surface portion that totally reflects the light incident inside from the incident portion with respect to the first direction substantially perpendicular to the incident portion, and a refraction angle incident inside from the incident portion. The light reflecting portion having a mirror surface at a position in contact with the continuously changing normal that totally reflects in the second direction parallel to the incident portion in the light near the maximum value is 6 ° or less with respect to the incident portion. Since there are a plurality of inclinations at least on the emission surface part or the opposing surface, the light reflection part emits light from the inside of the light guide plate in the second direction with an overall deviation of 6 ° or less. On the other hand, it can be condensed and emitted. In addition, light from the outside of the light guide plate can be incident on the light guide plate in a direction that is wider than the second direction by the light reflecting portion.
Furthermore, the light from the inside of the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.
The light emitted from the light exit surface of the light guide plate is tilted to 6 ° or less with respect to the incident portion when, for example, a prism sheet or a liquid crystal display device is placed above the light guide plate. The occurrence of moire can be prevented because the pitch of the portion and the pitch of the prism sheet and the pitch of the liquid crystal pixels of the liquid crystal display device do not coincide with each other.

  In the light guide plate according to the fourth aspect, since the light reflecting portion is connected or juxtaposed in the second direction, the second light is emitted when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion. It is possible to continuously or discontinuously emit light that is condensed and emitted in the direction of. Moreover, the light from the outside of the light guide plate can be continuously or discontinuously incident in the light guide plate in the direction in which the light spreads from the second direction with respect to the second direction. Therefore, it is possible to control the outgoing light of the light for the purpose as the final outgoing light.

  Furthermore, the light guide plate according to claim 5 is formed of a small convex portion with respect to a large curvature radius because the crossing angle is 50 ° to 90 ° extending and intersecting two tangents of the maximum width of the light reflecting portion. Can do. Therefore, a large amount of light from the inside of the light guide plate can be received by the light reflecting portion, and the light refracted downward from the incident portion of the light guide plate can be used effectively.

Moreover, the flat illumination device according to claim 6 includes a light source,
An incident portion that guides light from the light source, an emission surface portion that emits the light to the outside, and a side surface portion that is connected to the incidence portion and the emission surface portion at a substantially right angle, and incident light from the incident portion to the inside A mirror surface part that totally reflects in a first direction perpendicular to the first part, and total reflection in a second direction that is substantially parallel to the incident part in light near the maximum value of the refraction angle incident from the incident part. A light guide plate provided with a plurality of light reflection portions on the opposite surface facing the emission surface portion, with a mirror surface at a position in contact with the continuously changing normal line;
A reflector that reflects light from the side surface and the opposing surface of the light guide plate;
Since at least the light source, the light guide plate, and the case for housing the reflector are provided, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it is condensed and emitted in the second direction. The reflected light can be reflected by the reflector to the anti-emission part of the light guide plate, and at least these reflected lights can be incident in the light guide plate in a direction that is wider than the second direction by the light reflection part.
In particular, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion. Therefore, it is possible to obtain outgoing light having a wide viewing angle and high luminance from the outgoing surface portion.

Furthermore, the flat illumination device according to claim 7 includes a light source,
An incident portion that guides light from the light source, an emission surface portion that emits the light to the outside, and a side surface portion that is connected to the incidence portion and the emission surface portion at a substantially right angle, and emits light incident inside from the incident portion. A supercritical portion that breaks the critical angle of light existing inside is provided on the exit surface portion, a mirror surface portion that totally reflects the light incident inside from the entrance portion in a first direction substantially perpendicular to the entrance portion, and the entrance portion A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the refraction angle incident on the inside from A plurality of light guide plates provided on the opposing surface facing the emission surface portion,
A reflector that reflects light from the side surface and the opposing surface of the light guide plate;
Since at least the light source, the light guide plate, and the case for housing the reflector are provided, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it is condensed and emitted in the second direction. The reflected light can be reflected by the reflector to the light-exiting surface portion of the light guide plate, and at least the reflected light can be incident on the light guide plate in a direction that is wider than the second direction by the light reflection portion.
In particular, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.
In addition, light near the maximum value of the refraction angle incident in the light guide plate from the incident portion reaching the vicinity of the output surface portion or light incident in the direction in which the light reflection plate spreads out can be emitted from the output surface portion. it can. Therefore, it is possible to obtain emitted light having a wide viewing angle and a uniform brightness from the emitting surface portion.

  In the flat illumination device according to the eighth aspect, the light guide plate is mounted with an inclination of 6 ° or less with respect to the light source parallel to the incident portion, so that the light emitted from the light exit surface portion of the light guide plate and the light guide plate When a prism sheet, a liquid crystal display device, etc. is placed on the top of the LCD, the pitch of the light reflecting portion and the pitch of the prism sheet or the pitch of the liquid crystal pixels of the liquid crystal display device do not coincide with each other to prevent the occurrence of moire. it can. Therefore, it is possible to obtain easy-to-see outgoing light.

Furthermore, the flat illumination device according to claim 9 includes a light source,
An incident portion that guides light from the light source, and a front surface portion, a back surface portion, and a side surface portion that are connected at a substantially right angle to the incident portion, and the light incident on the inside from the incident portion with respect to the first direction substantially perpendicular to the incident portion And a mirror surface portion that totally reflects, and a continuously changing normal line that totally reflects in a second direction parallel to the incident portion in the light near the maximum value of the refraction angle incident inside from the incident portion. A light guide plate provided with a plurality of light reflection portions whose positions are mirror surfaces at least on the front surface portion or the back surface portion with an inclination shift of 6 ° or less with respect to the incident portion;
A reflector that reflects light from the side surface and the front or back surface of the light guide plate;
Since at least the light source, the light guide plate, and the case for housing the reflector are provided, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, it is condensed and emitted in the second direction. The reflected light can be reflected by the reflector to the light-exiting surface portion of the light guide plate, and at least the reflected light can be incident on the light guide plate in a direction that is wider than the second direction by the light reflection portion.
In particular, light in the vicinity of the maximum value of the refraction angle incident on the light guide plate can be totally reflected by the light reflecting portion, and the light can be condensed in the direction of the exit surface portion.
Further, since the inclination is shifted to 6 ° or less with respect to the incident portion, the light reflected from the light emitted from the light exit surface portion of the light guide plate and the prism sheet, the liquid crystal display device, or the like is placed on the light guide plate. The occurrence of moire can be prevented because the pitch of the prism does not coincide with the pitch of the prism sheet or the pitch of the liquid crystal pixels of the liquid crystal display device. For this reason, it is possible to obtain uniform and easy-to-see high-luminance outgoing light with a wide viewing angle.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The present invention includes a mirror surface portion that totally reflects light incident from the incident portion with respect to a first direction substantially perpendicular to the incident portion, and a portion of light near the maximum refraction angle incident from the incident portion. And a light guide plate provided with a plurality of light reflection portions on the front surface portion, the back surface portion, etc., with a mirror surface at a position in contact with a continuously changing normal that totally reflects in a second direction substantially parallel to the incident portion, A flat illumination device is configured by including a light source, a reflector that reflects light from a side surface portion and a front surface portion or a back surface portion of the light guide plate, and a case that houses the light source, the light guide plate, and the reflector. .
Thereby, when the light from the inside of a light-guide plate is radiate | emitted outside by a light reflection part, it can condense and radiate | emit with respect to a 2nd direction. In addition, light from the outside of the light guide plate can be incident on the light guide plate in a direction that is wider than the second direction by the light reflecting portion.

In addition, since light from the inside of the light guide plate is totally reflected by the light reflecting portion and condensed in the direction of the exit surface, the light refracted downward from the incident portion of the light guide plate can be used effectively. High-intensity outgoing light can be obtained.
Then, by the reflector provided at the lower part of the back surface of the light guide plate, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, the light emitted by being condensed in the second direction is guided. The light is reflected on the light exit surface of the light plate. Accordingly, the reflected light can be incident on the light guide plate in a direction having a spread with respect to the second direction by the light reflecting portion.
In addition, light near the maximum value of the refraction angle incident in the light guide plate from the incident portion reaching the vicinity of the output surface portion or light incident in the direction in which the light reflection plate spreads out can be emitted from the output surface portion. it can. Therefore, it is possible to obtain emitted light having a wide viewing angle and a uniform brightness from the emitting surface portion.

  Furthermore, since the light guide plate itself and the light guide plate are tilted at an angle of 6 ° or less with respect to the incident portion, the light emitted from the light exit surface portion of the light guide plate and the prism sheet, the liquid crystal display device, etc. are placed on the light guide plate. In this case, it is possible to prevent the occurrence of moire because the pitch of the light reflecting portion and the pitch of the prism sheet and the pitch of the liquid crystal pixels of the liquid crystal display device do not coincide with each other.

  1 and FIG. 2 are schematic perspective views of a flat illumination device according to the present invention, FIGS. 3 to 6 are schematic light trajectories of the light guide plate according to the present invention, and FIG. 7 is a schematic partial cross section of the light guide plate according to the present invention. 8 is a schematic rear view of the light guide plate according to the present invention, and FIG. 9 is a schematic perspective view of the flat illumination device 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, a reflector 10, a reflector 11, and a case 12.

  The light guide plate 2 includes an incident portion 3 that guides light from the light source 9, a reflection end surface portion 3 b (anti-incident portion 3 b) located in the opposite direction of the incident portion 3, and an emission surface 4 (here, surface). Portion 4, hereinafter referred to as surface portion 4), a back surface portion 5 positioned in the direction opposite to the surface portion 4, and the incident surface 3, the surface portion 4, and the side surface portion 6 connected to the back surface portion 5. The light guide plate 2 has a wedge shape such that the thickness of the light guide plate 2 decreases from the incident portion 3 toward the reflection end surface portion 3b (anti-incident portion 3b).

A plurality of mirror surface portions 8 and light reflection portions 7 are alternately provided on the back surface portion 5 of the light guide plate 2. The mirror surface portion 8 totally reflects the light incident from the incident portion 3 into the light guide plate 2 in a first direction substantially perpendicular to the incident portion 3. The light reflecting portion 7 has a convex section with an arc cross section extending from the incident portion 3 toward the reflecting end surface portion 3b, and is in the vicinity of the maximum value of the refraction angle incident from the incident portion 3 into the light guide plate 2. The position in contact with the continuously changing normal that is totally reflected in the second direction substantially parallel to the incident portion 3 is defined as a mirror surface.
Furthermore, although the mirror surface portion 8 and the light reflection portion 7 are alternately provided here, the light reflection portion 7 may be provided continuously, or the number of the light reflection portions 7 may be increased and the number of the mirror surface portions 8 may be decreased. good.
Although not shown here, the mirror surface portion 8 and the light reflecting portion 7 are provided only on the back surface portion 5, but the mirror surface portion 8 and the light reflecting portion 7 may be provided on the front surface portion 4. You may provide the mirror surface part 8 and the light reflection part 7 in both surfaces of the back surface part 5. FIG.

  Here, the light guide plate 2 is shown as having a wedge shape such that the thickness of the light guide plate 2 decreases from the incident portion 3 toward the reflection end face portion (anti-incident portion) 3b. In the case of a wedge shape in which the size (height) of the light reflecting portion 7 itself is constant and the thickness of the light guide plate 2 itself becomes thinner from the incident portion 3 toward the reflecting end surface portion (anti-incident portion) 3b. In the case of a wedge shape in which the thickness of the light guide plate 2 itself is constant and the size (height) of the light reflecting portion 7 itself decreases from the incident portion 3 toward the reflecting end surface portion (anti-incident portion) 3b. There is.

  In the case of a wedge shape in which the size (height) of the light reflecting portion 7 itself is constant and the thickness of the light guide plate 2 itself becomes thinner from the incident portion 3 toward the reflecting end surface portion (anti-incident portion) 3b. The action of the light reflecting part 7 is constant from the incident part 3 through the reflection end face part (anti-incident part) 3b.

Further, a supercritical portion 14 is provided on the surface portion 4 of the light guide plate 2 so as to be emitted from the surface portion 4 so as to break the critical angle α.
In addition, as the supercritical part 14, processing, such as what was described in Unexamined-Japanese-Patent No. 2003-035824 etc., is given, for example.

  Here, FIG. 3 shows the trajectory of light reaching the light reflecting portion 7 of the back surface portion 5 of the light guide plate 2 from the outside. This FIG. 3 explains using the light which exists in the light-guide plate 2 for the reflector 11 provided in the lower position of the back surface part 5 of the light-guide plate 2. FIG. In FIG. 3, a light beam L1 (substantially most refracted light beam in the range of the refraction angle γ in the light guide plate 2) is reflected by the reflector 11 (here, completely reflected), and is reflected as a reflected light L1r. Proceed in 7 directions. The reflected light L1r is refracted by the light reflecting portion 7 and travels as a light beam L1G in the light guide plate 2 toward the surface portion 4.

  Similarly, the light beams L2, L3, and L4 are reflected (here, completely reflected) by the reflector 11, and travel in the direction of the light reflecting portion 7 as reflected light L2r, L3r, and L4r. These reflected lights L2r, L3r, and L4r are refracted by the light reflecting portion 7 and travel as light rays L2G, L3G, and L4G toward the inside of the light guide plate 2 and the surface portion 4 thereof.

As described above, the light beams L1, L2, L3, and L4 having the spread can be refracted by the light reflecting portion 7 and travel to the inside of the light guide plate 2 as the light beams having the spread.
Therefore, the light from the outside of the light guide plate 2 can be incident on the light reflecting portion 7 in the direction in which the light guide plate 2 spreads with respect to the second direction.

  4 shows parallel light rays Lh1, Lh2, Lh3, Lh4, and Lh5 emitted from the light reflecting portion 7 of the back surface portion 5 from the inside of the light guide plate 2, and provided at a lower position of the back surface portion 5 of the light guide plate 2. The light beam that has been completely reflected by the body 11 and then travels again from the light reflecting portion 7 into the light guide plate 2 will be described. In FIG. 4, a light ray Lh1 is refracted from the inside of the light guide plate 2 and radiated to the outside as outgoing light L01, reflected by the reflector 11 (here, completely reflected), and reflected light Lr1 is light. Proceed in the direction of the reflector 7. Then, the reflected light Lr1 is refracted again by the light reflecting portion 7, and proceeds as a light beam LG1 in the direction of the surface portion 4 inside the light guide plate 2.

  Similarly, the light beams Lh2, Lh3, Lh4, and Lh5 are refracted by the light reflecting portion 7 and emitted to the outside as outgoing lights L02, L03, L04, and L05, reflected by the reflector 11, and reflected light Lr2, Lr3, Lr4. It progresses to the light reflection part 7 direction as Lr5.

  Further, the reflected lights Lr2, Lr3, Lr4, and Lr5 that have traveled in the direction of the light reflecting portion 7 are refracted by the light reflecting portion 7 again, and light rays LG2, LG3, LG4, and LG5 are formed inside the light guide plate 2 and in the surface portion 4 direction. move on.

In this way, the light from the inside of the light guide plate 2 is refracted by the light reflecting portion 7 and condensed and emitted in the second direction when emitted to the outside.
In addition, the light refracted by the light reflecting portion 7 again is condensed with respect to the second direction.

  Further, in FIG. 5, similarly to the above, the light from the inside of the light guide plate 2 is emitted from the light reflecting portion 7 of the back surface portion 5 and is completely reflected by the reflector 11 provided at the lower position of the back surface portion 5 of the light guide plate 2. After that, the light beam that travels from the light reflecting portion 7 into the light guide plate 2 will be described again.

  In FIG. 5, the light beam LI <b> 1 is refracted from the light reflecting portion 7 from the inside of the light guide plate 2 and is emitted to the outside as outgoing light L <b> 01, reflected by the reflector 11, and proceeds to the light reflecting portion 7 as reflected light Lr <b> 1. The reflected light Lr1 is refracted again by the light reflecting portion 7 and travels as a light beam L1G in the light guide plate 2 toward the surface portion 4.

Similarly, the light beams LI2 and LI3 are refracted by the light reflecting portion 7 and are emitted to the outside as emitted light L02 and L03, reflected by the reflector 11, and travel in the direction of the light reflecting portion 7 as reflected light Lr2 and Lr3. These reflected lights Lr2 and Lr3 are refracted by the light reflecting portion 7 again and travel as light rays LG2 and LG3 in the light guide plate 2 and in the direction of the surface portion 4.
However, among the light beams, LI 4 is totally reflected by the light reflecting portion 7 and proceeds as a light beam Lp in the light guide plate 2 toward the surface portion 4.

  In this way, light that converges on the light reflecting portion 7 is emitted from the light reflecting portion 7 to the outside once and then completely reflected, and then proceeds to the light reflecting portion 7 again and refracted by the light reflecting portion 7. The flow of light travels in the direction of the surface portion 4 with a spread as a reversible symmetrical direction.

  In addition, FIG. 6 illustrates light at an incident angle with respect to the light reflecting portion 7 such as a light ray (light ray LI4) totally reflected by the light reflecting portion 7 in FIG.

In FIG. 6, the light beam LoP1 from the inside of the light guide plate 2 is totally reflected by the light reflecting portion 7 and travels in the direction of the surface portion 4 inside the light guide plate 2 as reflected light LP1.
Similarly, the light beams LoP2, LoP3, LoP4, and LoP5 are totally reflected by the light reflecting portion 7 and travel in the direction of the surface portion 4 inside the light guide plate 2 as reflected light LP2, LP3, LP4, LP5.

  In this way, the light totally reflected by the light reflecting portion 7 from the inside of the light guide plate 2 is condensed and travels in the direction of the surface portion 4 (outgoing surface portion).

  Further, although not shown here, the light beam that has been emitted from the light reflecting portion 7 from the inside of the light guide plate 2 and has been reflected by the reflector 11 and reached the mirror surface portion 8 of the light guide plate 2 is refracted by the mirror surface portion 8. Later, it proceeds in the direction of the surface portion 4.

  Therefore, the mirror surface part 8 that totally reflects the light incident from the incident part 3 into the light guide plate 2 with respect to the first direction substantially perpendicular to the incident part 3, and the refraction angle incident from the incident part 3 into the light guide plate 2. A light reflecting portion 7 having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion 3 in the light near the maximum value of By providing a plurality, the light refracted downward from the incident portion 3 of the light guide plate 2 can be used effectively. In particular, the light near the maximum value of the refraction angle incident on the light guide plate 2 is totally reflected to increase the luminance. Can be obtained.

  Although not shown here, the light guide plate 2 breaks the critical angle of light existing in the light guide plate 2 at the surface portion 4 (outgoing surface portion) that emits the light incident into the light guide plate 2 from the incident portion 3. By providing the supercritical portion 14, the light incident on the surface portion 4 at an angle close to the critical angle can break the incident angle by the supercritical portion 14 and be emitted to the outside of the surface portion 4. For this reason, the light from the incident part 3 can be used more effectively, and uniform and high-intensity outgoing light can be obtained.

FIG. 7 shows a schematic cross-sectional view in which the mirror surface portions 8 and the light reflection portions 7 are alternately provided. In the example of FIG. 7, the crossing angle β that extends and intersects the two tangent lines s1 of the maximum width of the light reflecting portion 7 (the width between the connection points with the mirror surface portions 8 on both sides) is provided in the range of 53 ° to 62 °.
Here, as an example of the actual light guide plate 2, the crossing angle β = 52.3888 °, the radius of curvature r = 0.0285 mm, the convex height of the light reflecting portion 7 is 0.148 mm, and the width is 0.05 mm. And processed. The width of the mirror surface portion 8 was 0.005 mm.

  The mirror surface portion 8 is formed of a plane substantially parallel to the surface portion 4, and the action of light in the light guide plate 2 is as described above, and light incident on the light guide plate 2 is (refractive index in the case of acrylic resin). N = 1.49) It proceeds into the light guide plate 2 within the range of the refraction angle γ = ± 42 °, and the critical angle α is about 42 ° at the boundary surface between the light guide plate 2 and the air layer. If the accumulated angle by the angle does not exceed the critical angle α, it does not leak to the outside of the light guide plate 2, and the same applies to light from the outside of the light guide plate 2 (light from the reflector 11, etc.). Since the light from 11 etc. has a reflection angle greater than the critical angle α, the light from the outside is guided into the light guide plate 2.

The light reflecting portion 7 refracts light from the inside of the light guide plate 2 and condenses and emits the light in the second direction when the light is emitted to the outside. The light totally reflected by the light reflecting portion 7 is condensed in the direction of the surface portion 4 and proceeds.
In addition, light from the outside of the light guide plate 2 can be incident on the inside of the light guide plate 2 in a direction having a spread with respect to the second direction by the light reflecting portion 7.

  In this way, the crossing angle β extending and intersecting the two tangents s1 of the maximum width of the light reflecting portion 7 of the light guide plate 2 is a small convex portion with respect to a large curvature radius such as 53 ° to 62 °. A large amount of light from the inside of the light plate 2 can be received by the light reflecting portion 7, and light refracted downward from the incident portion 3 of the light guide plate 2 can be used effectively.

  Although not shown here, when the light from the inside of the light guide plate 2 is emitted to the outside by the light reflecting portion 7 by the combination of the light reflecting portion 7 and the mirror surface portion 8, the light is condensed in the second direction. The light emitted from the outside of the light guide plate 2 can be emitted continuously or discontinuously, and the light from the outside of the light guide plate 2 can be made continuous by the light reflecting portion 7 in the direction extending in the second direction inside the light guide plate 2. Or can be incident non-continuously, and the final outgoing light can be controlled with respect to the outgoing light.

  Further, as shown in FIG. 8, the light guide plate 2 can be provided with a plurality of light reflecting portions 7 and mirror surface portions 8 with an inclination angle of θ = 6 ° or less with respect to the incident portion 3. Here, the light reflecting portions 7 and the mirror surface portions 8 are alternately provided.

  Although not shown here, as described above, the light reflection portion 7 and the mirror surface portion 8 of the light guide plate 2 itself are not provided with an inclination deviation of the inclination angle θ = 6 ° or less with respect to the incident portion 3. The light guide plate 2 having no inclination (inclination angle θ = 0) is placed with an inclination angle θ of 6 ° or less with respect to the light source 9, the reflector 10, and the side surface of the case 12 or the reflector 11 on the light source 9 side. You may do it.

  Here, the inclination angle θ = 6 ° or less is that light reflection occurs when the side surface of the reflecting portion 7 parallel to the direction of the side surface portion 6 of the light guide plate 2 has an inclination of 6 ° or more with the incident portion 3. Since the critical angle α is exceeded in the side surface direction of the portion 7 and light leaks from the light reflecting portion 7, the inclination angle θ is set to 6 ° or less.

  As described above, since the entire light guide plate 2 has a deviation of 6 ° or less, the light emitted from the surface portion 4 (light emission surface portion) of the light guide plate 2 is, for example, a prism sheet or a liquid crystal display device (not shown) above the light guide plate 2. And the like, the tilt angle of 6 ° or less with respect to the incident angle 3 is provided, so that the phase of the pitch of the light reflecting portion 7 and the pitch of the prism sheet and the pitch of the liquid crystal pixels of the liquid crystal display device do not coincide with each other. In addition, generation of moire can be prevented.

The light source 9 includes a cold cathode fluorescent lamp (CCFL) or a semiconductor light emitting element (such as an LED or a laser).
Cold cathode fluorescent lamps (CCFLs) are provided with electrodes on both ends of a thin quartz glass tube, etc., and are colored by a fluorescent material applied to the inside of the tube and applied to almost the entire wavelength range of color temperature including ultraviolet rays and RGB. It emits light in a cylindrical shape.
In addition, the semiconductor light emitting device uses three primary colors of red light emission, green light emission, and blue light emission in a linear form (array form) such as a high-intensity light emitting element of a quaternary compound or a compound such as InGaAlP, InGaAlN, and InGaN. .

Further, a light emission color mixed by a light emission color from a wavelength conversion material (YAG system) excited and emitted by light from the semiconductor light emitting element and a light emission color of the semiconductor light emitting element itself may be used.
In this case, for example, a wavelength conversion material (YAG system) that is excited by light from a blue light emitting InGaAlN semiconductor light emitting element and emits yellow or orange light is provided around the semiconductor light emitting element, and the blue color of the semiconductor light emitting element itself is provided. It is possible to obtain a white emission color mixed by the emission color and the emission color such as yellow or orange from the wavelength conversion material.

  The reflector 10 is composed of a sheet metal or a thermoplastic resin mixed with a white material such as titanium oxide or a sheet of a thermoplastic resin, such as a metal vapor deposition such as aluminum, or a metal foil laminated. The light source 9 provided in the vicinity of the incident portion 3 of the light plate 2 is surrounded except for the portion opposed to the incident portion 3 of the light guide plate 2.

  In addition, the reflector 10 has a reflection surface having a concavo-convex shape or a prism shape, and the reflected light from the reflector 10 is made to be scattered light, so that the portion where the luminance is reduced near the electrode of the light source 9 is corrected and the uniform reflected light is obtained. Then, most of the light emitted from the light source 9 is directed to the incident portion 3 of the light guide plate 2.

The reflector 11 is made by press-molding a thin metal plate having excellent reflectivity such as aluminum or stainless steel.
Further, it is made by injection molding a thermoplastic resin mixed with a white material such as titanium oxide, or by depositing metal such as aluminum on the thermoplastic resin, or by laminating a metal foil.

  The reflector 11 is provided below the back surface portion 5 of the light guide plate 2 to return the leaked light from the light guide plate 2 and the light source 9 to the light guide plate 2 again.

  The case 12 is made of an insulating resin material such as a thin metal plate having excellent reflectivity such as aluminum or stainless steel, a modified polyamide, polybutylene terephthalate, nylon 46, an aromatic polyester, or the like, and has a light reflectivity. In order to improve the light-shielding property, white powder such as titanium oxide is mixed into a shape having an upper opening by heat injection molding.

  Further, the case 12 may be directly used by omitting the reflector 11 when the reflector 11 is placed on the bottom or made of a thin metal plate having excellent reflectivity.

  2 includes a light guide plate 2b, a light source 9a, a light source 9b, a reflector 10a, a reflector 10b, a reflector 11, and a case 12.

  The light guide plate 2 b includes two incident portions 3 that guide light from two light sources 9, an emission surface 4 that emits light (here, a surface portion 4, hereinafter referred to as a surface portion 4), and the opposite side of the surface portion 4. It has a planar rectangular shape including a back surface portion 5 positioned in the direction and the incident portion 3, the front surface portion 4, and a side surface portion 6 connected to the back surface portion 5.

  Similarly to the flat illumination device 1, the light guide plate 2 b totally reflects light incident on the back surface portion 5 from the incident portion 3 into the light guide plate 2 in a first direction substantially perpendicular to the incident portion 3. Of the mirror surface portion 8 and the light in the vicinity of the maximum value of the refraction angle incident on the light guide plate 2 from the incident portion 3, and continuously changing to be totally reflected in the second direction substantially parallel to the incident portion 3. A plurality of light reflecting portions 7 having a mirror surface at a position in contact with the normal line are provided.

Furthermore, although the mirror surface portion 8 and the light reflection portion 7 are alternately provided here, the light reflection portion 7 may be provided continuously, or the number of the light reflection portions 7 may be increased and the number of the mirror surface portions 8 may be decreased. good.
Although not shown here, the mirror surface 8 and the light reflecting portion 7 are provided only on the back surface portion 5, but may be provided on the front surface portion 4 or on both surfaces of the front surface portion 4 and the back surface portion 5.
Further, similarly to the light guide plate 2, a supercritical portion 14 is provided on the surface portion 4 of the light guide plate 2b.

In addition, the description about the part which overlaps with the planar illuminating device 1 demonstrated using FIG. 1 in the planar illuminating device 1b is abbreviate | omitted.
However, since the thickness of the light guide plate 2b is constant in the flat illumination device 1b, the taper leak unlike the flat illumination device 1 does not occur.
The case 12 houses the light guide plate 2 or the light guide plate 2b, the light source 9 or the light source 9a, the light source 9b, the reflector 10 or the reflector 10a, the reflector 10b, and the reflector 11, but other electronic components such as, for example, Parts necessary for a liquid crystal display device and the like may be stored together.

  Here, FIG. 9 shows an example of a flat illumination device in the case where the light reflecting portion 7 and the mirror surface portion 8 are provided on the emission surface portion (the front surface portion 4 and the back surface portion 5).

  The flat illumination device 1 shown in FIG. 9 has a mirror surface portion 8 that totally reflects light incident inside from the incident portion 3 in a first direction substantially perpendicular to the incident portion 3 and is incident inside from the incident portion 3. A light reflecting portion 7 having a mirror surface at a position in contact with a continuously changing normal that totally reflects in a second direction substantially parallel to the incident portion 3 in the light near the maximum value of the refraction angle. 4 and a plurality of light guide plates 2 c provided on the back surface portion 5, a light source 9, a reflector 10, a reflector 11, and a case 12.

On the back surface portion 5 side of the light guide plate 2c, the light reflecting portion 7 is provided so that the size (height) of the light reflecting portion 7 itself becomes lower from the incident portion 3 toward the reflection end surface portion (counter-incident portion) 3b. .
Therefore, the width of the light reflecting portion 7 becomes narrower from the incident portion 3 toward the reflecting end surface portion (anti-incident portion) 3b, and the mirror surface portion 8 moves from the incident portion 3 toward the reflecting end surface portion (anti-incident portion) 3b. Provide to be as wide as possible.

  In addition, a light reflecting portion 7 having a constant size (height) is provided on the emission surface portion (surface portion 4) so that the light reflecting portion 7 is continuously provided, and a mirror surface portion 8 is provided. The part is provided minutely.

  As described above, the functions and the like provided on the back surface portion 5 by changing the distribution and size of the light reflecting portions 7 provided on the front surface portion 4 and the back surface portion 5 of the light guide plate 2 are described above. Although the explanation is omitted, the action of the light reflecting portion 7 provided on the surface portion 4 can obtain a light collecting effect like a prism lens.

Thus, the mirror surface portion that totally reflects the light incident from the incident portion with respect to the first direction substantially perpendicular to the incident portion, and the light in the vicinity of the maximum value of the refraction angle incident from the incident portion into the light guide plate. In the light guide plate, a plurality of light reflecting portions having a mirror surface at a position in contact with a continuously changing normal line that is totally reflected in a second direction substantially parallel to the incident portion are provided. The light from the inside is totally reflected by the light reflecting portion, in particular, the light in the vicinity of the maximum value of the refraction angle incident on the light guide plate, so that high-luminance outgoing light can be obtained.
Further, when the light from the inside of the light guide plate is emitted to the outside by the light reflecting portion, the light is condensed and emitted in the second direction, and the light from the outside of the light guide plate is brought to the inside of the light guide plate by the light reflecting portion. It can enter in the direction which has a breadth with respect to the 2nd direction. Accordingly, a light guide plate that can effectively use light refracted downward from the incident portion can be provided.

  The light guide plate, the light source, and a case that houses the reflector that reflects light from the side surface portion and the front surface portion or the back surface portion of the light guide plate. The light that is condensed and emitted is reflected on the light-exiting surface portion of the light guide plate, and the reflected light can be incident on the light guide plate in the direction extending from the second direction by the light reflecting portion. Equipment can be provided.

  INDUSTRIAL APPLICABILITY The present invention can be used as a wide variety of backlights from small liquid crystal display devices to large liquid crystal display devices, and can provide light with particularly high luminance. Therefore, the present invention is provided for products that require high luminance such as car navigation systems. be able to.

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 locus diagram of the approximate light of the light guide plate concerning the present invention. It is a locus diagram of the approximate light of the light guide plate concerning the present invention. It is a locus diagram of the approximate light of the light guide plate concerning the present invention. It is a locus diagram of the approximate light of the light guide plate concerning the present invention. It is a general | schematic fragmentary sectional view of the light-guide plate which concerns on this invention. It is a schematic back view of the light guide plate according to the present invention. 1 is a schematic perspective view of a flat illumination device according to the present invention.

Explanation of symbols

1, 1b Planar illumination device 2, 2b, 2c Light guide plate 3 Incident part 3b Reflective end face part (anti-incident part)
4 Surface portion 5 Back surface portion 6 Side surface portion 7 Light reflection portion 8 Mirror surface portion 9, 9a, 9b Light source 10, 10a, 10b Reflector 11 Reflector 12 Case 14 Supercritical portion α Critical angle γ Refraction angle n Refractive index β Crossing angle θ Inclination angle s1 Tangent L1, L2, L3, L4 rays L1r, L2r, L3r, L4r rays L1G, L2G, L3G, L4G rays Lh1, Lh2, Lh3, Lh4, Lh5 rays L01, L02, L03, L04, L05 rays Lr1, Lr2, Lr3, Lr4, Lr5 light beam LG1, LG2, LG3, LG4, LG5 light beam LI1, LI2, LI3, LI4 light beam L1G, L2G, L3G, Lp light beam LoP2, LoP3, LoP4, LoP5 light beam LP1, LP2, LP3, LP4 LP5 rays

Claims (9)

In a light guide plate comprising an incident part that guides light from a light source, an emission surface part that emits the light to the outside, and a side part that is connected to the incident part and the emission surface part at a substantially right angle,
A mirror surface portion that totally reflects light incident on the light guide plate from the incident portion with respect to a first direction substantially perpendicular to the incident portion, and a maximum refraction angle incident on the light guide plate from the incident portion. A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the vicinity of the incident portion, and that faces the emitting surface portion A plurality of light guide plates are provided on the light guide plate. In a light guide plate comprising an incident part that guides light from a light source, an emission surface part that emits the light to the outside, and a side part that is connected to the incident part and the emission surface part at a substantially right angle,
A supercritical portion that breaks a critical angle of light existing in the light guide plate is provided on an exit surface portion that emits light incident on the light guide plate from the incident portion,
A mirror surface portion that totally reflects light incident on the light guide plate from the incident portion with respect to a first direction substantially perpendicular to the incident portion, and a maximum refraction angle incident on the light guide plate from the incident portion. A light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that is totally reflected in a second direction substantially parallel to the incident portion in the vicinity of the incident portion, and that faces the emitting surface portion A plurality of light guide plates are provided on the surface. The light guide plate includes a mirror surface portion that totally reflects light incident on the inside from the incident portion with respect to a first direction substantially perpendicular to the incident portion, and a vicinity of a maximum value of a refraction angle incident on the inside from the incident portion. The light reflecting portion having a mirror surface at a position in contact with a continuously changing normal that totally reflects in a second direction parallel to the incident portion in the light of 6 degrees or less is 6 ° or less with respect to the incident portion. 3. The light guide plate according to claim 1, wherein a plurality of light guide plates are provided at least on the emission surface portion or the opposing surface with an inclination shift. 3. The light guide plate according to claim 1, wherein the light reflecting portion is connected or juxtaposed in the second direction. 3. The light guide plate according to claim 1, wherein the light reflecting portion extends two tangents of the maximum width and has an intersecting angle of 50 ° to 90 °. A light source;
An incident portion that guides light from the light source, an exit surface portion that emits the light to the outside, and a side surface portion that is connected to the incident portion and the exit surface portion at a substantially right angle, and enters the interior from the incident portion. A mirror surface portion that totally reflects light in a first direction perpendicular to the incident portion, and a second portion that is substantially parallel to the incident portion in the light near the maximum value of the refraction angle incident inside from the incident portion. A light guide plate provided with a plurality of light reflection portions on the opposite surface opposite to the emission surface portion, with a mirror surface at a position in contact with a continuously changing normal that totally reflects in the direction of
A reflector that reflects light from the side surface and the facing surface of the light guide plate;
A flat illumination device comprising at least a case for housing the light source, the light guide plate, and the reflector. A light source;
An incident portion that guides light from the light source, an exit surface portion that emits the light to the outside, and a side surface portion that is connected to the incident portion and the exit surface portion at a substantially right angle, and enters the interior from the incident portion. A supercritical portion that breaks the critical angle of light existing inside is provided on the emission surface portion that emits light, and the light incident inside from the incident portion is totally reflected in a first direction substantially perpendicular to the incident portion. A mirror surface portion that is in contact with a continuously changing normal line that is totally reflected in a second direction substantially parallel to the incident portion in the light near the maximum value of the refraction angle incident inside from the incident portion. A light guide plate provided with a plurality of light reflecting portions whose positions are mirror surfaces on the facing surface facing the emitting surface portion;
A reflector that reflects light from the side surface and the facing surface of the light guide plate;
A flat illumination device comprising at least a case for housing the light source, the light guide plate, and the reflector. 8. The flat illumination device according to claim 6, wherein the light guide plate is placed with an inclination of 6 ° or less with respect to the light source parallel to the incident portion. 9. A light source;
The light source includes an incident portion that guides light from the light source, and a front surface portion, a back surface portion, and a side surface portion that are connected to the incident portion at a substantially right angle, and a light incident on the inside from the incident portion is substantially perpendicular to the incident portion. A mirror surface part that totally reflects in the direction of the light beam, and a continuous reflection that totally reflects in the second direction parallel to the incident part in the light near the maximum value of the refraction angle incident inside from the incident part. A light reflecting plate having a mirror surface at a position in contact with the changing normal and a plurality of light guide plates provided at least on the front surface portion or the back surface portion with an inclination of 6 ° or less with respect to the incident portion;
A reflector that reflects light from the side surface portion and the front surface portion or the back surface portion of the light guide plate;
A flat illumination device comprising at least a case for housing the light source, the light guide plate, and the reflector.

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