JP4295782B2 - Light guide - Google Patents

Description

The present invention is optimal for providing a large flat illumination device, and there is no critical part between the incident end face part and the outgoing face part, and even if a plurality of them are arranged, the adjacent boundary parts are not conspicuous as lines, and are opposed to each other . Alternatively, the light guided in the uniform direction from the two pairs of uniform plane incident end face portions can be emitted from the large flat portion and can be self-supported by the light guide itself without using the support. It is about the body.

  Conventional light guides for large screens use the two side surfaces and the four side surfaces as the incident surface for the purpose of making the light guide itself large and maximally utilizing the light from the light source. Further, a method is known in which the light guide plate is formed into a so-called wedge shape that is thinned away from the incident end face part, and a taper leak of light from the incident end face part in the opposite direction to the incident end face part is used. .

  In the case of a large flat illumination device for a large screen, a method is known in which light sources such as cold cathode fluorescent tubes are arranged in a case without using a light guide, and a diffusion plate is used in the upper part.

  As a conventional light guide for a large screen, it is necessary when the light guide itself is enlarged and the two side surfaces or the four side surfaces are used as the incident surface for the purpose of maximizing the light from the light source. A light guide corresponding to the size is required. For this reason, as the size of the light guide increases, the occurrence of bending occurs due to the weight of the light guide. In order to avoid the occurrence of this bending, it is necessary to increase the thickness of the light guide, and there is a problem that the weight of the light guide increases. In addition, in the method of forming the light guide in a so-called wedge shape that decreases the thickness as the distance from the incident end surface portion increases, the taper leak of light from the incident end surface portion in the opposite direction to the incident end surface portion is used. However, there is a problem that it is difficult to maintain the strength and retention of the portion where the thickness is reduced. In addition, when these light guides are enlarged, it is necessary to increase the number of light sources in order to improve the luminance, and there is a problem that the thickness of the incident end face part must be increased.

  Furthermore, when a plurality of conventional light guides are used in order to increase the screen size, there is a problem that adjacent boundary portions that are end portions of the light guide are conspicuous as lines.

  Further, in the case of a conventional flat illumination device in which a light source is provided on the side surface of the light guide, since the light source is located on the side surface, the light emitted from the light guide is light along the output surface of the light guide. There is a problem that a large amount of light is emitted.

Furthermore, in the case of a conventional large flat illumination device that obtains a large screen, a so-called direct-type back, in which a light source such as a cold cathode fluorescent tube is arranged in a case without using a light guide, and a diffusion plate is used in the upper part. In the flat illumination device of a light, there exists a subject which must enlarge the magnitude | size of a case corresponding to the magnitude | size of a flat illumination device.
Moreover, when it becomes a certain size, there is a problem that the diffusion plate is bent by the weight of the diffusion plate itself. In order to avoid this bending, when a support part is provided, there is a problem in the shadow of the support part and the reduction in the brightness of the support part.

(Object of invention)
The present invention has been made to solve the above problems, there is no critical portion of the incident end face portion and the surface portion, inconspicuous as each other of the adjacent boundary portions that the line be more aligned, opposed 1 Light that is guided in a uniform direction from the pair or two pairs of uniform plane incident end face portions can be emitted from a large flat portion and can be self-supported by the light guide itself without using a support. To provide a light body.

The light guide according to claim 1 of the present invention includes an incident end face portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion that is located in a direction opposite to the exit surface portion, an exit surface portion, and a counter-exit portion. A light-emitting surface portion and a light-exiting surface portion, each of which includes a flat portion and an inclined surface in which two ends of the light-emitting surface portion are inclined in the direction of the light-exiting surface portion. the side portion connected in parallel to the flat portion of the exit surface portions, the two parallel side portions, and the incident end face for guiding the light light emitted from the inclined surface and the flat portion, and the incident end face portion is uniform made a plane, situated outside the flat portion of the exit surface and anti-emitting surface, a plurality of light guide inclined surfaces of mutual emitting surface, characterized in that arranged adjacent to face.

The light guide according to claim 1 includes an incident end surface portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion located in a direction opposite to the exit surface portion, an exit surface portion, and an anti-exit surface portion. And a light emitting surface portion and a non-light emitting surface portion, each of which includes a flat portion and an inclined surface in which two ends of the light emitting surface portion are inclined in the direction of the light emitting surface portion, and the side surface connecting the light emitting surface portion and the light emitting surface portion part was parallel to the flat portion of the exit surface portions, the two parallel side portions, from the incident end face for guiding the light light emitted from the inclined surface and the flat portion, and the incident end face portion is uniform plane becomes positioned outside the flat portion of the exit surface and anti-emitting surface, since a plurality of light guide inclined surfaces to each other of the emission surface portion arranged adjacent to face, the inclined surface and the flat portion of the exit surface portion The light is emitted from and there is no critical part between the incident end face part and the surface part. The boundary portions adjacent to each other are not conspicuous as lines, and light guided from a pair of opposite incident end surface portions can be emitted from a large flat portion and can be self-supported without using a support. .

In addition, the light guide according to claim 2 includes an incident end face portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion that is located in a direction opposite to the exit surface portion, an exit surface portion, and an anti-exit surface portion. The exit surface portion and the counter-exit surface portion are composed of a flat portion and an inclined surface in which the four ends of the exit surface portion are inclined toward the counter-exit surface portion, and the exit surface portion and the counter-exit surface portion are connected to each other. the side surface portion which is parallel to the flat portion of the exit surface portions, the parallel four side portions, and the incident end face for guiding the light light emitted from the flat portion and the inclined surface, and the incident end face portion is uniform It consists of a plane , is located outside the flat portion of the exit surface portion and the counter-exit surface portion, and a plurality of light guides are arranged adjacent to each other so that the inclined surfaces of the exit surface portions face each other.

The light guide according to claim 2 includes an incident end surface portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion located in a direction opposite to the exit surface portion, an exit surface portion, and an anti-exit surface portion. And a light emitting surface portion and a non-light emitting surface portion, each of which includes a flat portion and an inclined surface in which four ends of the light emitting surface portion are inclined in the direction of the light emitting surface portion, and the side surface connecting the light emitting surface portion and the light emitting surface portion. part was parallel to the flat portion of the exit surface portions, the parallel four side portions, from the incident end face for guiding the light light emitted from the inclined surface and the flat portion, and the incident end face portion is uniform plane becomes positioned outside the flat portion of the exit surface and anti-emitting surface, since a plurality of light guide inclined surfaces to each other of the emission surface portion arranged adjacent to face, the inclined surface and the flat portion of the exit surface portion The light is emitted from and there is no critical part between the incident end face part and the surface part. The adjacent boundary portion is not conspicuous as a line, and the light guided from the two pairs of incident end face portions facing each other can be emitted from the large flat portion, and the light guide itself can stand on its own without using a support. it can.

Further, the light guide according to claim 3 is characterized in that light deflecting elements that refract and totally reflect light are provided on the exit surface portion and the opposite exit surface portion .

The light guide according to claim 3 is provided with the light deflecting element that refracts and totally reflects light on the exit surface portion and the opposite exit surface portion , so that the inclined portions at the two ends or the four ends of the light guide inclined toward the surface portion, and Uniform and equivalent light can be emitted from the surface portion.

As described above, the light guide according to claim 1 includes an incident end surface portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion that is located in a direction opposite to the exit surface portion, and an exit surface portion. A light emitting surface portion and a light emitting surface portion, each of the light emitting surface portion and the light emitting surface portion including a flat portion and an inclined surface in which two ends of the light emitting surface portion are inclined toward the light emitting surface portion. Sorted parallel to the flat portion of the emission face side portion connecting the, the two parallel side portions, and the incident end face for guiding the light light emitted from the inclined surface and the flat portion, and the incident end surface portion made from a uniform plane, and located outside the flat portion of the exit surface and anti-emitting surface, a plurality of light guide inclined surfaces of mutual emitting surface portion so arranged adjacently to face, the exit face Light is emitted from the flat part and the inclined surface, and there is no critical part between the incident end face part and the surface part. Even if a plurality of lines are arranged, the adjacent boundary portions are not conspicuous as lines, and light guided from a pair of opposed incident end surface portions can be emitted from a large flat portion, and the light guide itself is self-supporting without using a support. can do. Thereby, the light guide of the magnitude | size corresponding to the planar illuminating device of the target magnitude | size can be obtained by arranging many light guides.

The light guide according to claim 2 includes an incident end surface portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion located in a direction opposite to the exit surface portion, an exit surface portion, and an anti-exit surface portion. And a light emitting surface portion and a non-light emitting surface portion, each of which includes a flat portion and an inclined surface in which four ends of the light emitting surface portion are inclined in the direction of the light emitting surface portion, and the side surface connecting the light emitting surface portion and the light emitting surface portion. part was parallel to the flat portion of the exit surface portions, the parallel four side portions, from the incident end face for guiding the light light emitted from the inclined surface and the flat portion, and the incident end face portion is uniform plane becomes positioned outside the flat portion of the exit surface and anti-emitting surface, since a plurality of light guide inclined surfaces to each other of the emission surface portion arranged adjacent to face, the inclined surface and the flat portion of the exit surface portion The light is emitted from and there is no critical part between the incident end face part and the surface part. The adjacent boundary portion is not conspicuous as a line, and the light guided from the two pairs of incident end face portions facing each other can be emitted from the large flat portion, and the light guide itself can stand on its own without using a support. it can. Thereby, the light guide of the magnitude | size corresponding to the planar illuminating device of the target magnitude | size can be obtained by arranging many light guides.

The light guide according to claim 3 is provided with the light deflecting element that refracts and totally reflects light on the exit surface portion and the opposite exit surface portion , so that the inclined portions at the two ends or the four ends of the light guide inclined toward the surface portion, and Uniform and equivalent light can be emitted from the surface portion. Thereby, plane light can be obtained from the whole light guide including an inclined part.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The flat illumination device using the light guide of the present invention includes a light source, a first light guide that provides uniform light from the light source, and light from the first light guide. It is comprised from the 2nd light guide which can radiate | emit from a large flat part. The second light guide includes an incident end surface portion that guides light, an exit surface portion that emits the guided light, a counter-exit surface portion that is located in a direction opposite to the exit surface portion, and an exit surface portion and a counter-exit surface portion. A light emitting surface portion and a non-light emitting surface portion are formed of a flat portion and an inclined surface, and the incident end surface portion is formed of two opposing pairs of uniform planes and is parallel to the flat portion. Thus, it is wider than the flat portion of the exit surface portion and the opposite exit surface portion, and is positioned below the flat portion of the opposite exit surface portion . Thus, the light incident from the incident end face reaches the exit surface while repeating total reflection at the inclined surface, the light deflecting element is provided on the exit surface and anti emitting surface and the inclined surface portion, a part of the light incident from the incident end face It emits an inclined surface portion, the total reflection on the exit face direction by light deflection element provided in the counter-emitting surface, or emitted from the direct emission surface portion, emitted from the emission surface by the light deflection element the light that has reached the exit surface portion be able to.

Further, the planar light to be incident on the incident end surface portion of the second light guide is incident on the elongated light incident surface portion that guides the light from the light source by the first light guide and the position facing the incident surface portion. The emission surface portion having a width wider than the surface portion, and the incident surface portion and the emission surface portion are connected to each other, and are composed of two inclined side surfaces and two side surfaces facing each other. And, part of the light guided from the light source to the incident surface part directly reaches the output surface part, and the light refracted greatly at the incident surface part is totally reflected by the inclined side surface and reaches the output surface part substantially vertically, and from this output surface part The light is emitted and travels toward the incident end face of the second light guide. Therefore, the exit surface portion of the first light guide has a width approximately twice that of the incident end surface portion of the second light guide, and the second light without leaving the light from the exit surface portion of the first light guide. It is possible to obtain uniform planar light from the flat portion of the emission surface portion of the second light guide.

  1A is a schematic perspective view of a flat illumination device including a light guide according to the present invention, FIG. 1B is a schematic cross-sectional view of the flat illumination device of FIG. 1A, and FIG. FIGS. 3B and 3B are views showing the second light guide according to the present invention, FIG. 4 is a view showing the light path of the second light guide, and FIG. FIG. 6 is a diagram showing the locus of light of the first light guide.

As shown in FIG. 1, the flat illumination device 1 is schematically configured to include a first light guide 3, a second light guide 2, a light source 9, and a reflector 10. In the flat illumination device 1, light is guided from the light source 9 provided in the vicinity of the incident surface portion of the first light guide 3 surrounded by the reflector 10 to the first light guide 3. The second light guide 2 is disposed on the exit surface portion of the first light guide 3 so that a plurality (two) of incident end face portions come in contact with or in the vicinity thereof. Thereby, the light emitted from the emission surface portion of the first light guide 3 is taken in from the incident end surface portion of the second light guide 2, and the light is emitted from the wide flat portion 5 a of the emission surface portion 5.

  The first light guide 3 and the second light guide 2 are formed of a transparent acrylic resin (PMMA) or polycarbonate (PC) having a refractive index of about 1.4 to 1.7.

As shown in FIGS. 2A and 2B, the second light guide 2 (2A) has a flat portion 5a having a large emission surface 5. This 2nd light guide 2A forms the inclined surface part 5b which inclines a pair of 2 opposing both ends of the output surface part 5 in the anti-output surface part 6 direction, and the output surface part 5 and the anti-output surface part 6 connect two A side surface portion 8 (corresponding to the thickness of the light guide 2A) , facing each other and parallel to the exit surface portion 5 and the opposite exit surface portion 6, and incident end surface portions 7 (7a, 7b) for guiding a pair of lights. ) Is formed. That is, FIG. 2 (a), the second light guide body 2A shown in (b), two parallel counter-emitting surface portion 6 end face of the inclined surface portion 5b of 2 ends facing each other and the exit surface portion 5 of the exit face 5 Incident end face portions 7a and 7b are formed.

Further, as shown in FIGS. 3A and 3B, the second light guide 2 (2B) has a flat portion 5a in which the emission surface portion 5 is large. The second light guide member 2B has an outer all four edges of the exit surface 5 to form an inclined surface portion 5b which is inclined in the counter-emitting surface portion 6 direction, two mutually opposed two pairs of the emitting surface portion 5 anti emitting surface portion 6 as input hurt surface 7 parallel to the bets are formed (7a, 7b, 7c, 7d ) a. That is, FIG. 3 (a), the second light guide body 2B shown in (b), the exit surface portion 5 the outer periphery of the inclined surface portion 5b of all four end end surface are four parallel counter-emitting surface portion 6 and the exit surface portion 5 Incident end face portions 7a, 7b, 7c and 7d are formed.

Incidentally, the boundary between the border and the flat portion 6a of the anti-emitting surface portion 6 of the flat portion 5a of the exit surface portion 5 and the inclined surface portion 5b and the inclined surface portion 6b forms a curved surface rounded, can not be recognized as a boundary It is like that.
The width of the incident end surface portion 7a, the width of the incident end surface portion 7b, the width of the incident end surface portion 7c, and the width of the incident end surface portion 7d are approximately the width of the exit surface portion from which the light from the first light guide 3 is emitted. It is half the size.

Furthermore, the flat portion 5a and the flat portion 6a and the inclined surface portion 5b and the inclined surface portion 6b of the anti-emitting surface portion 6 of the exit face 5 of the anti-emitting surface portion 6 of the exit face 5, an optical deflection element 11 for totally reflecting and refracting light, 12 is formed as necessary.

Next, the locus of light of the second light guide 2 (2A, 2B) will be described with reference to FIG.
The light incident from the incident end face portion 7 of the second light guide 2 (2A, 2B) is within the range where the refraction angle γ satisfies the expression 0 ≦ | γ | ≦ Sin ⁻¹ (1 / n). Proceed to 2A, 2B. For example, the refractive index n of acrylic resin, which is a resin material used for general light guides 2A and 2B, is about n = 1.49. Therefore, the maximum incident angle is 90 ° for the light from the inclined surface portion 5b direction to the inclined surface portion 6b direction and the light from the inclined surface portion 6b direction to the inclined surface portion 5b direction of the incident end surface portion 7. As a result, the refraction angle γ refracted at the incident end face portion 7 is in the range of γ = 0 to ± 42 °.
However, a straight line perpendicular to the incident end face portion 7 is γ = 0, and light rays exist in a range of γ = + 42 ° in the direction of each inclined surface portion 5b and γ = + 42 ° in the direction of the inclined surface portion 6b.

  Furthermore, the light that has entered the second light guides 2A and 2B within the range of the refraction angle γ = 0 to 42 ° is reflected between the second light guides 2A and 2B, the air layer (refractive index n = 1), and the like. The critical angle can be expressed by the equation Sinα = (1 / n). For example, since the refractive index n of acrylic resin, which is a resin material used for general light guides, is about n = 1.49, the critical angle α is about α = 42 °.

As described above, the light incident from the incident end face portion 7 is the second light guide in the range γ = 0 to ± 42 ° of the refractive index γ satisfying 0 ≦ | γ | ≦ Sin ⁻¹ (1 / n). 2A, 2B, and at the boundary between the second light guide 2 (2A, 2B) and the air layer (refractive index n = 1), Sin α = (1 / n) and the critical angle α = 42 °. It becomes. Accordingly, when the incident angle is larger than the critical angle, the light is totally reflected and is confined in the second light guides 2A and 2B unless it breaks the critical angle, and cannot escape from the second light guides 2A and 2B. .

A light ray incident from the incident end face portion 7 travels in the second light guides 2A and 2B within a refraction angle γ range γ = 0 ° to ± 42 °. The straight light L1 performs total reflection at the inclined surface portion 5b of the exit surface portion 5, the process proceeds to the flat portion 5a direction of the emission surface portion 5 at the same reflection angle as the incident angle of the inclined surface portion 5b of the exit surface portion 5. Light L2 having reached the flat portion 5a of the exit surface portion 5, an optical deflection element 11 emits light from the flat portion 5a of the to exit face 5 refracted by (where concave shape) L3 provided in the flat portion 5a of the emission surface portion 5 To be emitted.

Furthermore, refracted ± 42 ° beam Lr proceeding to inclined surface 5b direction of the inner exit surface 5 of the order of the ray (lateral direction in this case) at the incident end face portion 7, exit surface reaches the inclined surface 5b of the exit surface 5 5 is refracted by the light deflection element 12 (convex shape in this case) provided on the inclined surface portion 5b, and is emitted from the inclined surface portion 5b of the emission surface portion 5 as the emitted light Lr0.

Similarly, light rays LL of about ± 42 ° refracted on the inclined surface portion 6b direction of the reaction exit surface portion 6 of the entrance end face 7, advances to the inclined surface portion 6b direction of the reaction exit surface portion 6, the inclined surface portion 6b of the anti-emitting surface portion 6 from the inclined surface portion 5b of the exit surface 5 is refracted by the light deflecting device 12 provided on the inclined surface portion 5b of the exit surface portion 5 reaches the inclined surface 5b of the exit surface portion 5 on the opposite side by performing total reflection (here convex) The light is emitted as outgoing light LL0.

In addition, some of the light incident from the incident end face 7, advances while total reflection at the mirror surface portion of the inclined surface 6b of the inclined surface portion 5b and anti emitting surface of the exit surface portion 5, the flat portion 5a and anti of the emission surface portion 5 It reaches the flat portion 6 a of the emission surface portion 6. Then, the light beam L4 that has reached the flat portion 6a of the non -emission surface portion 6 is totally reflected again. Here, light rays L41 light deflector 11 (in this case where the recessed) reached provided in the flat portion 6a of the anti-emitting surface portion 6 is totally reflected by the light deflector 11 emitted from the flat portion 6a of the anti-emitting surface portion 6 proceeds to the flat portion 5a of the surface portion 5, is emitted as light L40.

Here, the light trajectory of only the left portion has been described with reference to FIG. 4, but a similar light trajectory is also obtained for the right portion. In particular, the outgoing light from the flat portion 5a of the outgoing surface portion 5 is incident on the left and right sides (here, two incident end face portions 7a and an incident end face portion 7b as shown in FIG. 2, and four incident lights as shown in FIG. 3). end face 7a, the incident end face 7b, the incident end face 7c, incident from the incident end face 7d.) from two incident end face 7 by incident light, the light from both the incident end face 7 of the exit surface 5 The light is emitted from the flat portion 5a.

Moreover, the optical deflecting elements 11 and the light deflector 12 distribution gradient of the emission surface portion 5 so as to have the brightness equal to that emitted from the luminance and the inclined surface portion 5b of the exit surface portion 5 emitted from the flat portion 5a of the emission surface portion 5 surface 5b, inclined surface 6b of the anti-emitting surface portion 6 can be obtained by controlling the amount of light deflecting device 11 and the light deflector 12 provided in the flat portion 5a and the flat portion 6a of the anti-emitting surface portion 6 of the exit face 5 .

The light deflection elements 11 and 12 emit optimal light from the flat portion 5a of the emission surface portion 5 from a part of a sphere and an elliptical sphere, a triangular pyramid, a cone, a quadrangular pyramid, a triangular prism, a quadrangular prism, and a cylinder. To choose.
For example, when the position of the light deflecting element 12 provided in the flat portion 5a of the emission surface portion 5 is in the leftward of the second light guide member 2 in FIG. 4, be emitted in the direction of the center of the flat portion 5a of the more outgoing surface portion 5 When it is necessary to obtain the outgoing light along the flat part 5a of the outgoing surface part 5 by using a triangular pyramid or a quadrangular pyramid having a smaller angle of the surface to be refracted than a part of the arcuate surface of the convex sphere. Sometimes it is better.

As described above, the light deflection elements 11 and 12 select the necessary direction, brightness, and the like of the emitted light from the flat portion 5a of the emission surface portion 5 and the combination thereof. As a result, the light propagated by total reflection or the like from the incident end surface portions 7a, 7b, 7c, and 7d of the second light guide 2 is refracted and deflected, and is emitted from the central direction of the flat portion 5a of the emission surface portion 5. It can radiate | emit uniformly from the whole flat part 5a of the 2nd light guide 2 by incident light.

Further, the second light guide body 2 is flat portions 5a and the inclined surface portion 5b of the emitted light and output surface portion 5 from the flat portion 5a of the emission surface portion 5 without the boundary between the inclined surface portion 5b of the exit surface 5 of the exit face 5 The emitted light from the entire outgoing surface portion 5 including the inclined surface portion 5b is emitted uniformly.

  As shown in FIG. 5, the first light guide 3 is positioned on the opposite side of the incident surface portion 36, which has a long and narrow rectangular shape for guiding light from the light source 9, and the width of the incident surface portion 36. A light emitting surface 35 that emits light from the light source 9 with a wider width, two slender inclined side surfaces 37 that connect the incident surface portion 36 and the light emitting surface portion 35, and the two inclined side surfaces 37 and the incident surface portion. 36 and two side surfaces 38 that vertically connect the emission surface portion 35.

Further, the first light guide 3 has a width of the exit surface portion 35 that is equal to the width of the incident end surface portion 7a and the width of the incident end surface portion 7b of the second light guide 2, and the width of the incident end surface portion 7c and the incident end surface portion 7d. Is approximately twice as large as the width of.
However, the length of the first light guide 3 is equal to the length of the second light guide 2.

Further, the locus of light of the first light guide 3 will be described with reference to FIG.
As described in the second light guide 2 (2A, 2B), the light incident from the incident surface portion 36 of the first light guide 3 has a refraction angle γ of 0 ≦ | γ | ≦ Sin ⁻¹ (1 / N) is advanced into the light guide 3 within a range satisfying the equation. For example, since the refractive index n of an acrylic resin, which is a resin material used for the general light guide 3, is about n = 1.49, the maximum incident angle is 90 °. Therefore, the refraction angle γ refracted at the incident surface portion 36 is in the range of γ = 0 to ± 42 °.
However, a straight line perpendicular to the incident surface portion 36 is γ = 0, and there is a light beam in a range of γ = + 42 ° to the right of each inclined side surface 37 and γ = + 42 ° to the left of the inclined side surface 37.

  In addition, the light incident on the first light guide 3 within the range of the refraction angle γ = 0 to ± 42 ° is the boundary surface between the first light guide 3 and the air layer (refractive index n = 1). The critical angle can be expressed by the equation Sinα = (1 / n). For example, since the refractive index n of acrylic resin, which is a resin material used for general light guides, is about n = 1.49, the critical angle α is about α = 42 °.

The straight light beam L13 incident from the incident surface portion 36 of the first light guide 3 is directly refracted by the incident surface portion 36 and the output surface portion 35 and is directly emitted from the output surface portion 35.
A light beam having a slight incident angle with respect to the light emission surface portion 35 is emitted from the light emission surface portion 35 with a light beam that is slightly refracted.

The light beam Lr3 that has been refracted by the portion 36 and travels to the left of the inner inclined side surface 37 of a light beam of about ± 42 ° (here, in the left-right direction) is totally reflected by the left inclined side surface 37 and has a reflection angle equal to the incident angle. The light beam Lr31 travels in the direction of the emission surface portion 35, and is slightly refracted by the emission surface portion 35 to be emitted as a light beam Lr30.

  Similarly, a light beam LL3 that has been refracted by ± 42 ° at the incident surface portion 36 and proceeds to the right of the inner inclined side surface 37 is totally reflected by the left inclined side surface 37 and is emitted as a light beam LL31 at a reflection angle equal to the incident angle. Proceeding in the direction of the surface portion 35, the light is slightly refracted by the emission surface portion 35 and emitted as a light beam LL30.

  Note that the light deflection element 11 and the light deflection element 12 provided in the second light guide 2 may be provided on the emission surface portion 35, the two inclined side surfaces 37, and the two side surfaces 38.

  Light emitted from the exit surface portion 35 of the first light guide 3 is incident on the incident end surface portion 7a and the incident end surface portion 7b of the second light guide 2A or the incident end surface portion 7a and the incident end surface of the second light guide 2B. All of the outgoing light is incident on the portion 7b, the incident end face portion 7c, and the incident end face portion 7d.

The light source 9 is formed of a cold cathode tube (CCFL) or the like, which has a linear shape corresponding to the incident surface portion 36 of the first light guide 3, and direct light is incident on the first light guide 3. The light enters the light guide 3 from the surface 36 and other light enters the first light guide 3 through the space between the light source 9 and the reflector while being reflected by a reflector (not shown).
In addition, the light source 9 is a semiconductor light emitting element, which is composed of an LED, a laser, or the like, and is incident on a unit configured in an array shape including a plurality of semiconductor light emitting elements composed of RGB (red light emission, green light emission, blue light emission). You may provide in the surface part 36 vicinity.

  Incidentally, in the conventional flat illumination device, since the light from the light source is emitted from the light guide body immediately to emit the emitted light, there is generation of brightness spots and rainbows. One light guide 3 emits light corresponding to the second light guide 2, and the emitted light can be emitted by the second light guide 2 so that the light further spreads out.

  The reflector 10 has a reflective surface with an uneven shape or a prism shape, and a metal such as aluminum is deposited on a sheet of a thermoplastic resin mixed with a white material such as titanium oxide or a sheet of a thermoplastic resin. It consists of a laminate of foil or sheet metal. The reflector 10 covers portions other than the entrance surface portion 36 and the exit surface portion 35 of the first light guide 3, and light other than light emitted from the light source 9 to the exit surface portion 35 by the first light guide 3. Is reflected or diffusely reflected, and again incident on the first light guide 3, and all the light from the light source 9 is emitted from the emission surface portion 35.

  Further, since the reflecting surface of the reflector 10 has an uneven shape or a prism shape, the light source 9 can mix light of three primary colors such as RGB in the first light guide 3 by reflection by the prism surface, The efficiency of converting light from the light source 9 into light emitted from the light source 9 can be improved without wasting it.

  Although not shown here, a prism sheet may be used above the surface portion of the second light guide 2 as the flat illumination device 1. At this time, the prism surface (prism ridge) of the prism sheet is directed to the light guide 2. Thereby, when there is outgoing light along the second light guide 2, the outgoing light is once taken into the prism sheet, totally reflected on the surface opposite to the taken-in surface, and finally planar illumination A substantially vertical outgoing light can be obtained from the apparatus 1.

  In the above-described embodiment, the configuration in which the first light guide 3 is provided so that the emission surface 35 is located on the incident end surface 7 of the second light guide 2 has been described. Can also be used as the first light guide 3. In this case, the opening width of the reflector 10 is set so as to substantially match the width of the two incident end face portions 7 of the second light guide 2. Thereby, the light from the light source 9 enters from the two incident end surface portions (for example, 7a and 7b) of the two second light guides 2 from the opening of the reflector 10.

As described above, the flat illumination device including the light guide of the present invention guides the linear light source 9 and the light from the light source 9 from the incident surface portion 36 of the first light guide 3, and this first guide. The incident surface portion 36 is wider than the incident surface portion 36 of the light body 3, and is incident from the incident surface portion 36 by an exit surface portion 35 that emits light from the light source 9, and two inclined surface portions 37 that connect the incident surface portion 36 and the exit surface portion 35. The light that has been largely refracted is totally reflected and guided in the direction of the exit surface 35 to emit light substantially perpendicular to the exit surface 35, and is approximately half the width of the exit surface 35 of the first light guide 3. By the incident end surface portion 7 of the second light guide body 2 having a width, the emitted light from the first light guide body 3 is guided from the incident end surface portions 7 of the plurality of second light guide bodies 2, and second out of the 2 ends or 4 end of the exit surface 5 of the light guide 2 is tilted counterclockwise emission surface 6 direction, the second exit surface portion 5 of the light guide 2 anti Surface portion 6 light incident on the incident end face portion 7 obtained by parallel to the second conductive while repeating total reflection at the inclined surface portion 6b inclined to the inclined face portion 5b and anti emitting surface portion 6 side that is inclined exit surface portion 5 side The light is guided to the large flat portion 5a of the emission surface portion 5 of the light body 2, and is emitted to the outside by the light deflection element 11 and the light deflection element 12 provided on the flat portion 5a.
Further, by providing the light deflection element 11 and the light deflection element 12 also on the inclined surface portion 5b inclined to the emission surface portion 5 side, light can be emitted from the inclined surface portion 5b, and the large flat portion 5a and the emission surface of the emission surface portion 5 can be emitted. Equal and uniform light can be emitted from the inclined surface portion 5 b of the surface portion 5.

(A) It is a schematic perspective view of a flat illumination device including a light guide according to the present invention. (B) It is a side view of the same plane illuminating device. (A) It is a schematic perspective view of the light guide which concerns on this invention. (B) It is a side view of the light guide. (A) It is a schematic perspective view of the light guide which concerns on this invention. (B) It is a side view of the light guide. It is a locus diagram of the light guide according to the present invention. 1 is a schematic perspective view of a light guide according to the present invention. It is a locus diagram of the light guide according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar illumination apparatus 2 (2A, 2B), 3 Light guide 5 Output surface part 5a Surface flat part 5b Surface side inclined surface part 6 Anti-emission surface part 6a Back surface flat part 6b Back surface side inclined surface part 7 (7a, 7b, 7c, 7d) Incident end face part 8 Side face part 9 Light source 10 Reflector 11, 12 Light deflection element 35 Outgoing face part 36 Incident face part 37 Inclined side face 38 Side face γ Refraction angle n Refractive index α Critical angle L1, L2, L3, L4, LL, Lr, LL1 , Lr0, LL0, L41, L40, L13, LL3Lr3, LL30, L130Lr30

Claims (3)

A light guide having an incident end face part that guides light, an emission face part that emits the guided light, a counter-emission surface part located in a direction opposite to the emission surface part, and a side part connected to the emission surface part and the counter-emission surface part. A light body,
The exit surface portion and the counter-exit surface portion are composed of a flat portion and an inclined surface in which two ends of the exit surface portion are inclined in the counter-exit surface portion direction, and a side surface portion connecting the exit surface portion and the counter-exit surface portion is formed as described above. and parallel to the flat portion of the exit surface portions, the two parallel of the side portions, and with the entrance end face for guiding the light to the light emitted from said flat portion and the inclined surface, and the incident end face one consist such plane, positioned outward from the flat portion of the emission face and said anti-emitting surface portion, arranged adjacent a plurality of the light guide so that the inclined surface of the exit surface of each other are opposed A light guide characterized by that. A light guide having an incident end face part that guides light, an emission face part that emits the guided light, a counter-emission surface part located in a direction opposite to the emission surface part, and a side part connected to the emission surface part and the counter-emission surface part. A light body,
The exit surface portion and the counter-exit surface portion include a flat portion and an inclined surface in which four ends of the exit surface portion are inclined in the counter-exit surface portion direction, and the side surface portion connecting the exit surface portion and the counter-exit surface portion is the and parallel to the flat portion of the exit surface portions, the parallel four of the side portions, and with the entrance end face for guiding the light to the light emitted from said flat portion and the inclined surface, and the incident end face one consist such plane, positioned outward from the flat portion of the emission face and said anti-emitting surface portion, arranged adjacent a plurality of the light guide so that the inclined surface of the exit surface of each other are opposed A light guide characterized by that. 3. The light guide according to claim 1, wherein a light deflecting element that refracts and totally reflects light is provided on the emission surface portion and the non-light emission surface portion.

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