JP4170320B2 - Light guide plate and flat illumination device - Google Patents

Description

  In the present invention, a reflection element that totally reflects incident light in the direction of the emission surface portion is provided on the opposite emission surface portion, and the reflection light from the reflection element is refracted so as to be paired with this reflection element, and the emission is emitted outside. An angle characteristic element is provided on the exit surface, and the reflection element and the exit angle characteristic element are always paired, and the light from the light source is guided by the side surface and the end as the entrance end surface, and the light received by the reflection element. Is reliably directed to the output angle characteristic element as reflected light, and the output angle characteristic element surely emits light with a spread from the output surface portion, so that it is possible to obtain output light with a wide viewing angle and uniform brightness. The present invention relates to a light guide plate capable of obtaining a bright emitted light and a flat illumination device using the light guide plate and the like.

  As a conventional flat illumination device, a reflective member is provided on the front surface portion and the back surface portion of the light guide plate, and a cutout portion that is a band-like slit is provided on either one, and the smaller the cutout portion is closer to the light source, the light source is a dot-like shape. In some cases, an arc-shaped slit centering on the light emitting part of the point light source is provided so that the distance between the slits becomes narrower as the distance from the light source increases.

  Further, the conventional flat illumination device has a diffusing member on the front surface side of the light guide plate, a reflective member on the back surface side, and a V-shaped cross section having a predetermined length on the reflective surface (back surface) of the light guide plate. The V-shaped grooves are arranged in a row parallel to the light source and spaced apart from each other by a predetermined distance. Adjacent rows of the V-shaped grooves are alternately arranged in a staggered pattern, and the distance gradually increases as the distance from the light source increases. Those that are arranged so as to become smaller are also known.

  Furthermore, as a conventional light guide plate, a large number of V-groove recesses that are reflected and refracted on the entire front and back surfaces are provided intermittently in a staggered or arcuate manner parallel to the incident direction, and between the recesses along the light traveling direction. There is known a structure in which a gap is provided in the gap so that the interval gradually decreases as the distance from the light source increases.

Further, as a conventional flat illumination device, at least one substantially point-shaped primary light source, a light incident surface on which light emitted from the primary light source is incident, and a light output surface on which incident light is guided and emitted A surface light source system is constituted by a light guide body having a light source and a light deflection element that controls the direction of light emitted from the light guide body, and the primary light source is disposed at a corner portion or an end face of the light guide body. There are also known ones in which a large number of lens rows are arranged in parallel in a substantially arc shape so as to surround the primary light source on at least one side.
JP 62-109003 A Japanese Patent Laid-Open No. 5-216030 JP-A-8-286037 JP 2002-245823 A

The above-described conventional flat illumination device is provided with a reflective member on the front surface portion and the back surface portion of the light guide plate, and provided with a notch portion that is a strip-shaped slit on one of them, and by making the notch portion closer to the light source, the light source is reduced. The amount of light leaking from the slit is controlled as it is closer to, so that the entire light is emitted uniformly. However, since the emitted light has a slit shape, it looks bad. In particular, since the slit is small in the vicinity of the light source, it appears as a bright line, and there is a problem that the light is close to the light source and the energy of the light is large, resulting in a stronger bright line.
In addition, when the light source is point-like, an arc-shaped slit centering on the light emitting part of the point light source is provided so that the gap between the slits becomes narrower as the distance from the light source becomes larger. There is a problem that arc-like bright lines appear.

Further, as a conventional flat illumination device, the light guide plate has a diffusing portion on the front surface side, a reflective member on the back surface side, and a reflective surface (back surface) of the light guide plate having a predetermined length in a V shape. The V-shaped grooves are arranged in a row parallel to the light source and spaced apart from each other by a predetermined distance. Adjacent rows of the V-shaped grooves are alternately arranged in a staggered pattern, and the distance gradually increases as the distance from the light source increases. In a configuration in which the light guide plate is arranged to be small, the light incident on the light guide plate is reflected by the inclined surface of the V-shaped groove with respect to the traveling direction and deflected to the surface side. For this reason, since particularly strong emitted light is always emitted parallel to the light source, there is a problem that, for example, the luminance of the emitted light is lowered at both ends of the light source.
In particular, when the light source is a point light source, the luminance distribution is often not uniform depending on the position from the light source.

  In addition, as a conventional light guide plate, a large number of V-groove recesses that are reflected and refracted on the entire front and back surfaces are provided in a staggered or arcuate manner in parallel with the incident direction, and between the recesses along the light traveling direction In a configuration in which a gap is provided so that the interval gradually decreases as the distance from the light source increases, there is a problem that a large light guide plate is blocked by the depression even if the interval is gradually decreased as the distance from the light source increases.

  In addition, a large number of V-groove dents are provided intermittently in an arc shape with respect to the incident direction on the entire front and back surfaces, and the distribution is uniform even when the central portion of the cathode ray tube is strong and weak at the peripheral portion. However, in order to reflect the light from the central part of the cathode ray tube, it has an arc shape, and the parallel light from the cathode ray tube cannot be used. For this reason, the light from the central portion of the cathode ray tube can only be used from the oblique direction, has lower energy than the parallel light from the cathode ray tube, and the emission position (shape) of the reflected light is different (as a whole). There is a problem with the luminance distribution emitted from the surface.

  Further, as a conventional flat illumination device, at least one substantially point-shaped primary light source, a light incident surface on which light emitted from the primary light source is incident, and a light output surface on which incident light is guided and emitted A surface light source system comprising a light guide having a light source and a light deflection element for controlling the direction of light emitted from the light guide, wherein the primary light source is disposed at a corner or an end face of the light guide, In the case where a large number of lens arrays are arranged in parallel in a substantially arc shape so as to surround the primary light source on at least one side, firstly, the light of the primary light source is completely emitted from the light guide from the light incident surface. There is no means. Secondly, since all the light from the back surface is positively raised upward by the light deflecting element, there is a problem that the emitted light does not spread and becomes a narrow viewing angle as well as luminance spots.

  In any case, the conventional light guide plate is simply provided on the front surface portion or the back surface portion in the various reflection or refraction means provided on the front surface portion or the back surface portion. There was a problem that the light could not be used sufficiently because of the lack of relevance.

(Object of invention)
In the present invention, the position and the amount of light reflected by the back surface portion are directly applied to the front surface portion (exit surface portion) because the light reflected from the light source from the light source is emitted directly from the front surface portion. However, there is a problem in luminance spots, viewing angles, etc., but a reflection element that totally reflects incident light in the direction of the emission surface is provided on the anti-emission surface, and the reflected light from the reflection element is refracted to the outside. An exit angle characteristic element that emits light with a spread is provided on the exit surface part, and the reflection element and the exit angle characteristic element are always provided in pairs so that the light from the light source guided into the light guide plate The reflection element is totally reflected in the direction of the exit surface portion, and this reflected light reaches the exit angle characteristic element paired with the reflection element provided on the exit surface portion, and this light is reliably refracted by the exit angle characteristic element, and is emitted. Exit from the surface A light guide plate capable of obtaining a uniform bright outgoing light without luminance unevenness can be to provide a planar lighting device using the light guide plate or the like.

The light guide plate according to claim 1 of the present invention uses at least one side surface portion or at least one side surface portion as an incident end surface portion, and a reflection element that totally reflects incident light in the direction of the output surface portion. The exit surface is provided with an exit angle characteristic element that has an aperture on the exit surface and emits the totally reflected light from the reflection element by controlling the polar angle and the azimuth angle at the aperture and reflects the exit angle characteristic element and the reflection surface. the element characterized in that the kick set such that a pair always.

The light guide plate according to claim 1 has at least one adjacent side surface portion or at least one side surface as an incident end surface portion, and a reflection element that totally reflects incident light in the direction of the output surface portion is provided on the counter-exit surface portion . and with emission angle characteristic element provided emission angle characteristic element that emits totally reflected light from the reflecting element has an opening to exit face by controlling the polar angle and the azimuth angle at the opening on the exit surface and a reflective element since kicking set such that the pair always, can be emitted with a spread light guided to the light guide plate from reliably exit surface.

  The light guide plate according to claim 2 is characterized in that the reflective element is a reflective surface having an inclined surface portion in the direction of the incident end surface, and the reflective surface is a flat surface or a curved surface.

  In the light guide plate according to claim 2, the reflective element is a reflective surface having an inclined surface portion in the direction of the incident end surface, and the reflective surface is a flat surface or a curved surface. Different reflected light can be obtained.

  Furthermore, the light guide plate according to claim 3 is characterized in that the emission angle characteristic element is a refracting surface having an inclined surface portion in a direction opposite to the emitting surface portion, and the refracting surface is a flat surface or a curved surface.

  In the light guide plate according to claim 3, the output angle characteristic element is a refracting surface having an inclined surface portion in the direction of the counter-exiting surface, and the refracting surface is a flat surface or a curved surface. Light can be refracted in directions with different polar angles and azimuth angles.

  Further, in the light guide plate according to claim 4, the reflective element has at least one reflecting surface, and is from any one of a triangular prism concave shape, a trapezoidal cylindrical concave shape, a triangular pyramidal concave shape, a quadrangular pyramidal concave shape, and a conical concave shape. It is characterized by comprising.

  In the light guide plate according to claim 4, the reflecting element has at least one reflecting surface and is formed of any one of a triangular prism concave shape, a trapezoidal cylindrical concave shape, a triangular pyramid concave shape, a quadrangular pyramid concave shape, and a conical concave shape. The light from the incident end face can be totally reflected in the direction of the exit surface by the at least one reflecting surface, and the light from the other can also be totally reflected in the direction of the exit surface by the other reflecting surface.

  Furthermore, the light guide plate according to claim 5 is characterized in that the emission angle characteristic element has a plurality of refracting surfaces and is formed of any one of a triangular pyramid concave shape, a quadrangular pyramid concave shape, and a conical concave shape.

  In the light guide plate according to claim 5, the output angle characteristic element has a plurality of refractive surfaces and is formed of any one of a triangular pyramid concave shape, a quadrangular pyramid concave shape, and a conical concave shape. The total reflected light can be refracted by a plurality of refracting surfaces, and the number of refracting surfaces can be selected according to the purpose. For example, three faces can be selected for the triangular pyramid concave shape, four faces for the quadrangular pyramid concave shape, and an infinite plane for the conical concave shape.

  The light guide plate according to claim 6 is characterized in that the reflection element and the emission angle characteristic element are provided in parallel or in an arc shape with respect to the incident end face portion.

  In the light guide plate according to the sixth aspect, the reflection element and the emission angle characteristic element are provided in parallel or in an arc shape with respect to the incident end face portion, and therefore, can correspond to the directivity characteristic of light from the light source.

Furthermore, the flat illumination device according to claim 7 includes a light source,
An incident end face part that guides incident light from the light source, an exit face part that emits light from the incident end face part, a counter-exit face part that is located on the opposite side of the exit face part, and a side surface that intersects the exit face part and the counter exit face part A reflection element that totally reflects incident light in the direction of the exit surface portion is provided on the exit surface portion, and at least one side surface portion or at least one side surface portion is an entrance end surface portion. the emission angle characteristic element total reflection light from the reflection element has an aperture to control the polar angle and the azimuth angle at the opening for emitting is provided on the exit surface emission angle characteristic element and the reflective element pair always characterized in that at least and a set only LGP so that.

The flat illumination device according to claim 7 includes a light source,
An incident end face part that guides incident light from the light source, an exit face part that emits light from the incident end face part, a counter-exit face part that is located on the opposite side of the exit face part, and a side surface that intersects the exit face part and the counter exit face part A reflection element that totally reflects incident light in the direction of the exit surface portion is provided on the exit surface portion, and at least one side surface portion or at least one side surface portion is an entrance end surface portion. the emission angle characteristic element total reflection light from the reflection element has an aperture to control the polar angle and the azimuth angle at the opening for emitting is provided on the exit surface emission angle characteristic element and the reflective element pair always at least comprising a set only LGP so that guides light from a light source into the light guide plate, always because the reflective element and the emission angle characteristic elements are paired, from reliably emit face the light It can be emitted with a spread In addition, by selecting the quantity of light sources corresponding to the emission brightness and the size and shape of the light guide plate, the quantity of the incident end face part and the shape of the exit angle characteristic element of the exit face part and the reflection element of the non-emission face part (triangular pyramid) Concave shape, quadrangular pyramid concave shape, conical concave shape, etc.) can be changed.

As described above, the light guide plate according to claim 1 has a reflection element that totally reflects incident light in the direction of the exit surface portion with the end portion of at least one adjacent side surface portion or at least one side surface portion as the entrance end surface portion. An exit angle characteristic element is provided on the exit surface section, and an exit angle characteristic element is provided on the exit surface section. The exit surface section includes an opening section on the exit surface section, and emits totally reflected light from the reflection element by controlling the polar angle and azimuth angle at the opening section. a reflective element so kicking set so as to be paired always with the light guided in the light guide plate can be emitted with a spread from reliably exit surface. Therefore, it is possible to obtain outgoing light with a wide viewing angle and obtain uniform and bright outgoing light free from luminance spots.

  Further, in the light guide plate according to claim 2, since the reflecting element is a reflecting surface having an inclined surface portion in the direction of the incident end surface, and the reflecting surface is a flat surface or a curved surface, Reflected light with different angles can be obtained. For this reason, various types of light can be obtained with respect to the emission angle characteristic elements provided in pairs on the emission surface portion, and diversity can be obtained in the emission light, so that it is flexible with respect to the size and shape of the light guide plate. The size of the reflecting element and the emission angle characteristic element can be freely controlled as well as being able to cope. For example, even if the reflecting element is made small by making the inclined surface portion of the reflecting element a curved surface, the reflected light traveling toward the emission angle characteristic element can have the same positional relationship as when the inclined surface portion of the reflecting element is flat.

  Further, in the light guide plate according to claim 3, since the output angle characteristic element is a refracting surface having an inclined surface portion in the counter-exiting surface portion direction, and the refracting surface is a flat surface or a curved surface, Can be refracted in directions with different polar angles and azimuth angles. Therefore, the outgoing light can be refracted as outgoing light with more changes.

  Further, in the light guide plate according to claim 4, the reflective element has at least one reflecting surface, and is from any one of a triangular prism concave shape, a trapezoidal cylindrical concave shape, a triangular pyramidal concave shape, a quadrangular pyramidal concave shape, and a conical concave shape. Therefore, the light from the incident end face can be totally reflected in the direction of the exit surface by the at least one reflection surface, and the light from the other can also be totally reflected in the direction of the exit surface by the other reflection surface. Therefore, the light can be utilized to the maximum without waste. Further, because of these shapes, it is possible to easily manufacture a molding die or the like.

  Furthermore, in the light guide plate according to claim 5, since the output angle characteristic element has a plurality of refracting surfaces and is formed of any one of a triangular pyramid concave shape, a quadrangular pyramid concave shape, and a conical concave shape, Total reflected light from the element can be refracted by a plurality of refracting surfaces, and the number of refracting surfaces can be selected according to the purpose. For example, three faces can be selected for the triangular pyramid concave shape, four faces for the quadrangular pyramid concave shape, and an infinite plane for the conical concave shape. Therefore, the outgoing azimuth angle of the outgoing light can be freely selected, and the polar angle can be freely selected according to the inclination of the refracting surface.

  In the light guide plate according to the sixth aspect, the reflection element and the emission angle characteristic element are provided in parallel or in an arc shape with respect to the incident end face portion, and therefore can correspond to the directivity characteristic of light from the light source. Therefore, it is possible to freely select the type of light source and the overall shape.

Furthermore, the flat illumination device according to claim 7 includes a light source,
An incident end face part that guides incident light from the light source, an exit face part that emits light from the incident end face part, a counter-exit face part that is located on the opposite side of the exit face part, and a side surface that intersects the exit face part and the counter exit face part A reflection element that totally reflects incident light in the direction of the exit surface portion is provided on the exit surface portion, and at least one side surface portion or at least one side surface portion is an entrance end surface portion. the emission angle characteristic element total reflection light from the reflection element has an aperture to control the polar angle and the azimuth angle at the opening for emitting is provided on the exit surface emission angle characteristic element and the reflective element pair always at least comprising a set only LGP so that guides light from a light source into the light guide plate, always because the reflective element and the emission angle characteristic elements are paired, from reliably emit face the light It can be emitted with a spread In addition, by selecting the quantity of light sources corresponding to the emission brightness and the size and shape of the light guide plate, the quantity of the incident end face part and the shape of the exit angle characteristic element of the exit face part and the reflection element of the non-emission face part (triangular pyramid) Concave shape, quadrangular pyramid concave shape, conical concave shape, etc.) can be changed. Therefore, it is possible to obtain outgoing light with a wide viewing angle and obtain uniform and bright outgoing light without luminance spots.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the present invention, the incident end surface portion that guides the light from the light source to the light guide plate is the end portion or side surface portion of the adjacent side surface portion of the light guide plate as the incident end surface portion, and the light emitted from the guided light source is emitted to the outside. With the surface portion and the opposite side of the exit surface portion as the opposite exit surface portion, a reflective element having a triangular pyramid concave shape, a quadrangular pyramid concave shape, a conical concave shape or the like that totally reflects incident light in the direction of the exit surface portion is provided on the opposite exit surface portion. Reflecting the reflected light from the reflective element so that it is always paired with the reflective element so that it always receives the reflected light from the reflective element, an outgoing angle characteristic element that radiates and emits the light outside is provided on the outgoing surface part for reflection. The reflected light from the element reaches the emission angle characteristic element, and the reflected light is reliably refracted by the emission angle characteristic element and emitted from the emission surface with a spread, so that emission light having a wide viewing angle can be obtained. Uniform and bright with no brightness spots A light guide plate capable of obtaining emission light and is intended to provide a planar lighting device.

  1 to 3 are schematic perspective views of a flat illumination device according to the present invention, FIG. 4 is a schematic enlarged view of a reflecting element provided on the light exit surface side of the light guide plate according to the present invention, and FIG. FIG. 6 is a schematic enlarged view of an emission angle characteristic element provided on the emission surface side of the light plate, and FIG. 6 is a three-dimensional light locus diagram of the light guide plate according to the present invention. 1 to 3, only a part of the reflecting element provided in a pair with the emission angle characteristic element is indicated by a broken line.

  A flat illumination device 1 shown in FIG. 1 includes a light guide plate 2, a light source 9, a reflector 10, and a case 11. Here, a cold cathode fluorescent discharge tube (CCFL) is used as the light source 9.

  The light guide plate 2 is formed of a transparent acrylic resin (PMMA) or polycarbonate (PC) having a refractive index of about 1.4 to 1.7. As shown in FIG. 1, the light guide plate 2 is positioned on the opposite side of the exit surface portion 6, the entrance end surface portion 3 that guides light from the light source 9, the exit surface portion 6 that emits light from the entrance end surface portion 3. The light emitting surface portion 5 and the side surface portion 4 intersecting the light emitting surface portion 6 and the light emitting surface portion 5 are formed. A plurality of reflection elements 7 that totally reflect in the direction of the emission surface portion 6 are provided on the non-emission surface portion 5. The exit surface portion 6 is paired with the reflecting element 7 provided on the counter-exit surface portion 5 with an output angle characteristic element 8 that refracts the reflected light from the reflection element 7 provided on the counter-exit surface portion 5 and emits the light with a spread outside. A plurality of them are provided.

  A flat illumination device 1 b shown in FIG. 2 is schematically configured to include a light guide plate 2, a light source 9, and a case 11. Here, a plurality of semiconductor light emitting elements are used as the light source 9.

  A flat illumination device 1c shown in FIG. 3 is schematically configured to include a light guide plate 2b, a light source 9, and a case 11. Similar to the light guide plate 2, the light guide plate 2b is formed of a transparent acrylic resin (PMMA) or polycarbonate (PC) having a refractive index of about 1.4 to 1.7. As shown in FIG. 3, the light guide plate 2 b is located on the incident end surface portion 3 that guides light from the light source 9, the emission surface portion 6 that emits light from the incident end surface portion 3, and the opposite side of the emission surface portion 6. The light-exiting surface portion 5 and the side surface portion 4 intersecting with the light-emitting surface portion 6 and the anti-light-emitting surface portion 5 are provided, and the incident end surface portion 3 is provided at the end portion of the adjacent side surface portion 4. Here, a semiconductor light emitting element is used as the light source 9 at the corner of the light guide plate 2b.

The light incident from the incident end face part 3 of the light guide plate 2 or the light guide plate 2b enters the light guide plate 2 or the light guide plate 2b within a range where the refractive index γ satisfies 0 ≦ | γ | ≦ Sin ⁻¹ (1 / n). move on. For example, since the refractive index of acrylic resin, which is a resin material used for the general light guide plate 2 and light guide plate 2b, is about n = 1.49, the maximum incident angle is 90 °. The refraction angle γ refracted at the incident end face portion 3 is in a range of γ = 0 to ± 42 °, and propagates from the incident end face portion 3 into the light guide plate 2 and the light guide plate 2b.

  Further, the light incident on the light guide plate 2 or the light guide plate 2b within the range of the refraction angle γ = 0 to ± 42 ° is a boundary between the light guide plate 2 or the light guide plate 2b and the air layer (refractive index n = 1). In the plane, the critical angle can be expressed by Sinα = (1 / n). For example, since the refractive index of acrylic resin, which is a resin material used for the general light guide plate 2 and light guide plate 2b, is about n = 1.49, the critical angle α is about α = 42 °. For this reason, if the light-emitting plate 2 or the light-exiting surface portion 5 of the light-guide plate 2b does not have a convex or concave portion that deflects the light beam or does not exceed the critical angle α, the light-guide plate 2 or the light-guide plate 2b The light travels in the opposite direction to the incident end face 3 while being totally reflected by the exit face 6 and the counter exit face 5.

  The non-emission surface portion 5 is provided with a plurality of reflection elements 7 as shown in FIG. 4 and totally reflects light from the incident end surface portion 3 in the direction of the emission surface portion 6.

  In addition, there are various methods for providing the reflective element 7 according to the purpose. For example, when the entire side surface 4 corresponding to the linear light source 9 in FIG. 1 is used as the incident end face 3 so as to be totally reflected substantially perpendicular to the direction of the exit face 6 (the polar angle is extremely small), The reflecting element 7 is provided in one direction so that the reflecting surface 17b reflecting the reflecting element 7 is parallel or the normal line of the incident end face part 3 coincides with the normal line of the reflecting surface 17b reflecting the reflecting element 7 (light source 9 when the azimuth angle of light from 9 is one direction).

  Similarly, the end portions of the adjacent side surface portions 4 corresponding to the substantially point-like light sources 9 are made incident end surfaces so as to be totally reflected substantially at right angles to the exit surface portion 6 direction (the polar angle is extremely small) as shown in FIG. In the case of the portion 3, the reflective elements 7 are radially provided so that the reflective surface reflected by the reflective element 7 matches the normal line of the incident end face portion 3 with the normal line of the reflective surface reflected by the reflective element 7 ( (When the azimuth angles of light from the light source 9 are different (radial)).

  Further, the anti-emission surface portion 5 reflects and reflects the light from the incident end surface portion 3 such that the azimuth angle and polar angle of the totally reflected light from the reflection element 7 change with respect to the direction of the emission surface portion 6 by the reflection element 7. The element 7 is provided so that the normal line of the reflecting surface is different (deviation).

  As shown in FIG. 4, the reflecting element 7 includes a triangular prism concave shape 7a, a trapezoidal cylindrical concave shape 7b, a triangular pyramid concave shape 7c, a quadrangular pyramid concave shape 7d, a conical concave shape 7e, etc., and has at least one reflective surface 17b. Thus, at least one reflecting surface 17b can be provided in the direction of the incident end surface portion 3, and the light from the incident end surface portion 3 can be totally reflected in the direction of the emitting surface portion 6 by the reflecting surface 17b. The reflective element 7 is not limited to the triangular pyramid concave shape 7c or the quadrangular pyramid concave shape 7d, but may be a polygonal pyramidal concave shape.

  Moreover, the triangular prism concave shape 7a of the reflecting element 7 has a reflecting surface 17b that totally reflects light from the direction of the incident end face 3 and a reflecting surface 17c on the opposite side of the reflecting surface 17b, and also emits light from the other side. Total reflection is possible in the direction of the surface portion 6.

  When the reflecting surface 17c does not have an inclination angle (perpendicular to the counter-exiting surface portion 5 direction or the emitting surface portion 6 direction), only the light from the incident end surface portion 3 direction is totally reflected.

  Similarly, the trapezoidal columnar concave shape 7b has a reflection surface 17b that totally reflects light from the direction of the incident end surface portion 3, a reflection surface 17c on the opposite side of the reflection surface 17b, and the reflection surface 17b and the reflection surface 17c. The planar surface 17d is connected, and the light from the other side can be totally reflected in the direction of the exit surface 6 by the reflective surface 17c, and the light that has not reached the reflective surface 17b or the reflective surface 17c is again completely reflected by the planar surface 17d. Propagate in the opposite direction of reflection and propagation.

  Furthermore, the triangular pyramid concave shape 7c has a reflecting surface 17b that totally reflects light from the direction of the incident end surface portion 3 and two reflecting surfaces 17c that are connected to the reflecting surface 17b, and light from the other side also faces the exit surface portion 6 direction. Can be totally reflected.

  When the two reflecting surfaces 17c are perpendicular to the opposite exit surface 5 direction and the exit surface 6 direction (the reflecting surface 17c has no inclination angle), only the light from the incident end surface 3 direction is totally reflected. . Further, when the connecting portions (ridges) of the adjacent reflecting surfaces 17b and reflecting surfaces 17c are directed in the direction of the incident end surface portion 3, the polar angle and the azimuth are different in the direction of the emitting surface portion 6 opposite to the incident end surface portion 3. Can be totally reflected.

  Similarly, the concave quadrangular pyramid shape 7d has a reflection surface 17b that totally reflects light from the direction of the incident end surface portion 3 and three reflection surfaces 17c that are similar to the reflection surface 17b. With the three reflection surfaces 17c, light from all the other can also be totally reflected in the direction of the exit surface portion 6.

  In addition, when the connection part (ridge) of the adjacent reflective surface 17b and the reflective surface 17c is orient | assigned to the incident end surface part 3 direction, a polar angle and an azimuth angle differ in the output surface part 6 direction opposite to the incident end surface part 3. Can be totally reflected.

  Furthermore, the conical concave shape 7e has a reflection surface 17b that totally reflects not only light from the direction of the incident end face 3 but also light from all directions, and can totally reflect in all directions.

  A plurality of emission angle characteristic elements 8 as shown in FIG. 5 are provided on the emission surface portion 6, and the totally reflected light from the reflection element 7 is refracted by the plurality of refracting surfaces 18b and emitted to the outside with a spread.

  The distribution of providing the emission angle characteristic element 8 is provided so as to be paired with the reflection element 7 of the non-emission surface portion 5. For example, when the emission angle characteristic element 8 is provided so that the reflected light from the reflection surface 17b of the non-emission surface portion 5 is paired with the reflection element 7 that has a remarkably small polar angle and is totally reflected substantially perpendicular to the emission surface portion 6 direction. The output angle characteristic element 8 is directly above the reflecting element 7 (the position where the thickness direction of the light guide plate 2 is Z and the other is the XY direction, the XY directions are the same and only the Z direction is changed). Provided on the exit surface 6.

  Further, the reflection element 7 is provided on the anti-emission surface portion 5 so that the normal line of the reflection surface 17b of the reflection element 7 is different from the straight line of light from the incident end surface portion 3, or the triangular pyramid shape of the reflection element 7 When the reflection surface 17b adjacent to each other such as the concave shape 7c or the concave pyramid shape 7d or the connection portion (ridge) of the reflection surface 17c is provided on the anti-light-emitting surface portion 5 in the direction of the incident end surface portion 3, the reflection from the reflection element 7 occurs. Since the light is totally reflected from the position of the reflecting element 7 with a polar angle and an azimuth angle different from each other, the light is provided on the emitting surface portion 6 at a position different in azimuth angle from the reflecting element 7 (the opposite direction of the incident end surface portion 3 having a spread, etc.) ).

  As shown in FIG. 5, the emission angle characteristic element 8 includes a triangular pyramid concave shape 8 b, a quadrangular pyramid concave shape 8 a, a conical concave shape 8 c, and the like, and reflects reflected light from the reflective element 7 on the counter-exit surface 5 to the opening 18. When the light is emitted from the outside, it can be refracted by the plurality of refracting surfaces 18b and emitted outside with a spread. Note that the emission angle characteristic element 8 is not limited to the triangular pyramid concave shape 8b or the quadrangular pyramid concave shape 8a, but may be a polygonal pyramidal concave shape.

  When the exit angle characteristic element 8 emits light with a spread to the outside, the azimuth angle changes depending on the shape of the triangular pyramid concave shape 8b, the quadrangular pyramid concave shape 8a, the conical concave shape 8c, and the position provided on the emission surface portion 6. In addition, the polar angle can be changed by the inclination of the refracting surface 18b of the emission angle characteristic element 8.

  Further, the triangular pyramid concave shape 8b of the emission angle characteristic element 8 has three refracting surfaces 18b and is connected to each other and intersects at the vertex 18c, and the reflected light from the reflecting element 7 on the non-emission surface portion 5 is reflected to the three refracting surfaces 18b. Thus, the light can be radiated from the opening 18 and spread outward in three directions (with a larger polar angle).

  Note that the exit portion can be controlled by changing the direction in which the triangular pyramid concave shape 8 b is provided on the exit surface portion 6. For example, when all the refracting surfaces 18b of the triangular pyramid concave shape 8b are directed in the direction of the incident end face part 3, and when all the ridge sides of the refracting surfaces 18b of the triangular pyramid concave shape 8b are directed in the direction of the incident end face part 3, The emission distribution is different and can be controlled according to the target distribution, and the refracting surface 18b of the triangular pyramid concave shape 8b and the ridge side of the refracting surface 18b may be provided alternately.

  Furthermore, the quadrangular pyramid shape 8a has four refracting surfaces 18b and is connected to each other and intersects at the apex 18c, and the reflected light from the reflecting element 7 on the counter-emitting surface portion 5 is refracted by the four refracting surfaces 18b to be opened. It is possible to emit light with a broadening from 18 to 4 directions (with a larger polar angle).

  Further, similarly to the triangular pyramid concave shape 8b, the emission portion can be controlled by changing the direction in which the quadrangular pyramid concave shape 8a is provided on the emission surface portion 6. For example, in the case where all the refracting surfaces 18b of the quadrangular pyramid shape 8a are directed in the direction of the incident end surface part 3, and in the case where all the ridge sides of the refracting surfaces 18b of the quadrangular pyramid concave shape 8a are directed in the direction of the incident end face part 3. The emission distribution is different and can be controlled according to the target distribution, and the refracting surface 18b of the quadrangular pyramid shape 8a and the ridge side of the refracting surface 18b may be provided alternately.

  The conical concave shape 8c has a peripheral refracting surface 18b having an apex 18c, and refracts the reflected light from the reflecting element 7 of the counter-exiting surface portion 5 on all the refracting surfaces 18b, and omnidirectionally from the opening 18 It is possible to emit light with a broadening outside (by increasing the polar angle). In addition, the way of spreading can be controlled by the inclination of the refractive surface 18b.

  The trajectory of light between the reflection element 7 on the opposite exit surface portion 5 and the exit angle characteristic element 8 on the exit surface portion 6 will be described with reference to FIG. This figure is a partially enlarged view.

  A reflective element 7 having a triangular prism concave shape 7 a is provided on the light-exiting surface portion 5 of the light guide plate 2 or 2 b, and the output angle characteristic element 8 having a quadrangular pyramid concave shape 8 a is reflected on the light-exiting surface portion 6 opposite to the anti-light-emitting surface portion 5. Provided in pairs (in the Z direction) with respect to the element 7.

  The linear light L0 guided into the light guide plate 2 or the light guide plate 2b from the incident end face part 3 of the light guide plate 2 or the light guide plate 2b (unless it is not coherent) is a light beam having a certain extent (practically more than light). As the reflecting element 7 is larger than the comparison, the light beam L1, the light beam L2, and the light beam L3 travel in the direction of the triangular prism concave shape 7a of the reflective element 7 and are substantially perpendicular (perpendicular) by the reflecting surface 17b of the triangular prism concave shape 7a. Reflected light Lr1, reflected light Lr2, reflected light Lr3, etc. (originally, four rays should be drawn but omitted because they are difficult to see) are true of the triangular prism concave shape 7a. The outgoing light L1o and the outgoing light L2o refracted from the opening 18 when reaching the refracting surface 18b of the quadrangular pyramid concave shape 8a which is the outgoing angle characteristic element 8 existing above and exiting from the refractive surface 18b to the outside (air layer). , Outgoing light L3o (Because it is difficult to see the figure here, the light beam to the refracting surface 18b opposite to the direction of the incident end face 3 is not drawn.) As shown in FIG. The light is emitted with a larger corner.

  As described above, the reflecting element 7 on the counter-exit surface portion 5 and the output angle characteristic element 8 on the exit surface portion 6 are provided in pairs. At this time, corresponding to the distribution (matrix, zigzag, random, radial, etc.) in which one of the reflective element 7 and the emission angle characteristic element 8 is provided on the light guide plate 2, the other is also made the same distribution.

  The light source 9 is a semiconductor light emitting device composed of integrated red light emission (R), green light emission (G), and blue light emission (B), a monochromatic light emitting semiconductor light emitting device of these semiconductor light emitting devices, and a single color light emitting semiconductor light emitting device in an array shape. Or a pseudo white semiconductor light emitting device using a blue light emitting semiconductor light emitting device and a fluorescent material, or the like. Further, as the light source 9, CCFL (cold cathode fluorescent discharge tube) or HCFL (hot cathode fluorescent discharge tube) can be used, and an emitted light color suitable for the purpose can be selected.

  The reflector 10 is made of a sheet in which a white material such as titanium oxide is mixed into a thermoplastic resin or a sheet of a thermoplastic resin such as aluminum or a metal foil laminated or a sheet metal. The light source 9 provided in the vicinity of the incident end face portion 3 of the optical plate 2 is surrounded.

  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. To.

  The case 11 is made of a material in which a white material such as titanium oxide is mixed in a thermoplastic resin, a material in which a metal vapor deposition such as aluminum is applied to a thermoplastic resin, or a metal foil is laminated. The case 11 is configured to house the light guide plate 2 and the light guide plate 2b in the illustrated example, but basically covers the light source 9 except the light emitting surface, the incident end surface portion 3 and the light emitting surface portion 6, and the light source 9 and the light emitting surface 9. Light such as leakage light other than that emitted to the surface portion 6 is reflected and incident again on the light guide plates 2 and 2b.

  In place of the case 11 of this example, a reflector is provided on the back side of the light guide plates 2 and 2b to reflect light such as leaked light other than that emitted to the light source 9 and the exit surface 6 and again to the light guide plates 2 and 2b. It can also be set as the structure which injects into 2b. Further, a reflector may be disposed on the back side of the light guide plates 2 and 2 b and provided in the case 11.

  Thus, the flat illumination device 1, the flat illumination device 1 b, and the flat illumination device 1 c have a triangular prism concave shape 7 a and a trapezoid that totally reflects incident light in the direction of the emission surface portion 6 toward the light-exiting surface portion 5 of the light guide plate 2 or the light guide plate 2 b. A reflecting element 7 such as a columnar concave shape 7b, a triangular pyramidal concave shape 7c, a quadrangular pyramidal concave shape 7d, and a conical concave shape 7e is provided, and is always paired with the reflective element 7 so as to always receive the reflected light from the reflective element 7. As shown, the output angle characteristic element 8 such as a triangular pyramid concave shape 8b, a quadrangular pyramid concave shape 8a, and a conical concave shape 8c that refracts the reflected light from the reflective element 7 and emits the externally widened light to the outgoing surface portion 6 is formed. The reflected light from the reflecting element 7 reaches the emission angle characteristic element 8, and the reflected light is reliably refracted by the emission angle characteristic element 8 and emitted from the emission surface portion 6 with a spread, so that the viewing angle is wide. Can get outgoing light A light guide plate capable of obtaining bright light emitted uniform no brightness unevenness with and is intended to provide a flat lighting device.

  Suitable for all sizes from the backlight of small mobile products to large backlights, and the light of the final emitted light from the flat illumination device has a wide spread, so a wide viewing angle can be obtained. For this reason, it is possible to provide a light guide plate and a flat illumination device that can be widely used from mobile liquid crystal devices such as outdoors and car navigation systems to large-sized liquid crystal televisions.

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. 1 is a schematic perspective view of a flat illumination device according to the present invention. FIG. 6 is a schematic enlarged view of a reflective element provided on the opposite side of the light guide plate according to the present invention. It is a substantially enlarged view of the emission angle characteristic element provided on the emission surface side of the light guide plate according to the present invention. It is a three-dimensional light locus diagram of the light guide plate according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1b, 1c Planar illuminating device 2, 2b Light-guide plate 3 Incident end surface part 4 Side part 5 Anti-emission surface part 6 Output surface part 7 Reflective element 7a Triangular prism concave shape 7b Trapezoidal column concave shape 7c Triangular pyramid concave shape 7d Square pyramidal concave shape 7e Conical concave shape 8 Output angle characteristic element 8a Quadrangular pyramidal concave shape 8b Triangular pyramidal concave shape 8c Conical concave shape 9 Light source 10 Reflector 11 Case γ Refraction angle n Refractive index α Critical angle L0, L1, L2, L3, Lr1, Lr2, Lr3 , L1o, L2o, L3o rays

Claims (7)

An incident end face part that guides incident light from a light source, an exit face part that emits light from the incident end face part, a counter-exit face part located on the opposite side of the exit face part, the exit face part and the counter-exit face part In the light guide plate having a side portion intersecting with
At least one of the adjacent side surface portions or at least one of the side surface portions is used as the incident end surface portion, and a reflection element that totally reflects the incident light in the direction of the output surface portion is provided on the anti-output surface portion, and the output surface portion the reflection and the emission angle characteristic element with the emission angle characteristic element total reflection light from the reflecting element has an opening for emitting by controlling the polar angle and azimuth angle in the opening provided in the exit surface portion a light guide plate and the element, characterized in that the kick set such that a pair always. The light guide plate according to claim 1, wherein the reflection element is a reflection surface having an inclined surface portion in the direction of the incident end surface portion, and the reflection surface is a flat surface or a curved surface. The light guide plate according to claim 1, wherein the emission angle characteristic element is a refracting surface having an inclined surface portion in a direction opposite to the opposite emission surface portion, and the refracting surface is a flat surface or a curved surface. 2. The reflective element according to claim 1, wherein the reflective element has at least one reflective surface and is formed of any one of a triangular prism concave shape, a trapezoidal cylindrical concave shape, a triangular pyramidal concave shape, a quadrangular pyramidal concave shape, and a conical concave shape. The light guide plate described. 2. The light guide plate according to claim 1, wherein the emission angle characteristic element has a plurality of the refracting surfaces and has any one of a triangular pyramid concave shape, a quadrangular pyramid concave shape, and a conical concave shape. The light guide plate according to claim 1, wherein the reflection element and the emission angle characteristic element are provided in parallel or in an arc shape with respect to the incident end face portion. A light source;
An incident end face part that guides incident light from the light source, an exit face part that emits light from the incident end face part, a counter-exit face part located on the opposite side of the exit face part, the exit face part, and the counter-exit face part A reflecting element that totally reflects the incident light in the direction of the exit surface portion, with the end portion of at least one adjacent side surface portion or at least one of the side surface portions as the entrance end surface portion. An exit angle characteristic element provided on the opposite exit surface portion and having an opening portion on the exit surface portion and emitting totally reflected light from the reflection element by controlling a polar angle and an azimuth angle at the opening portion is provided on the exit surface portion. flat illumination device, wherein said that the emission angle characteristics element and said reflecting element has at least and a set only LGP so that the pair always provided with.

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