JP2010040351A - Light guide plate and planar light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate that performs a uniform illumination by suppressing brightness and darkness in a wide range on an emitting face without using a diffusion plate. <P>SOLUTION: The light guide plate 10 includes a light guide body 11 in which light from a light source 20 enters from an end face 11a, a plurality of protrusions 12 which are formed projecting to an outgoing side of the light guide body 11 and emit light guided in the light guide plate body 11, and a plurality of reflection parts 13 which are formed in a plurality of groove shapes in parallel so as to cross the light guide direction X on an opposed face opposing on the outgoing side of the light guide body 11, and reflect the light toward the protrusions 12. The protrusions 12 have first protrusions 121 which are formed in a near area E1 of the end face 11a and second protrusions 122 formed in a far area E2 separated further from the end face 11a than the near area E1. The number of the reflection parts 13 mutually opposed to the second protrusions 122 is made larger than the number of the reflection parts 13 mutually opposed to the first protrusions 121, and the amount of light emitted from the second protrusions 122 is made more than the amount of light emitted from the first protrusions 121. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light guide plate that guides light from a light source incident from an end surface of a light guide body and emits the light from an exit surface, and a surface light emitting device having the light guide plate.

  Some display devices have a surface light source device arranged as a backlight on the back side of the liquid crystal panel. The backlight is roughly classified into an edge light system and a direct system. The edge light system is a system in which light from a light emitter (CCT, LED, etc.) at the end of a light guide plate provided behind a display is transmitted and reflected by a light guide plate to a predetermined area. The direct method is a method in which a light source such as an LED is disposed behind the display and light diffused by a diffusion plate or the like is transmitted.

Patent Document 1 describes a structure for efficiently emitting incident light to the front surface of a light guide plate without using a diffuser plate such as a prism sheet even when a light source arranged in a dot shape is used in the edge light system. Has been. Specifically, in the light guide plate, a plurality of grooves for reflecting the light incident on the light guide plate from the point light source toward the exit surface are arranged, and a lens-shaped protrusion on the exit surface is orthogonal to the direction in which the grooves extend. A plurality are provided so as to extend in the direction of the movement. The lens-shaped protrusions efficiently emit incident light to the front surface of the light guide plate without using a diffusion plate, and suppress the generation of bright lines.
JP-A-2005-71610

  However, in the light guide plate shown in Patent Document 1 described above, a lot of light is emitted from the front side near the light source, and less light is emitted from the front side than the light source near the light source. There was a problem that. For this reason, the amount of light emitted from the front surface of the light guide plate cannot be made uniform, and the luminance difference is visually recognized as a spot by a viewer. That is, when the light guide plate of Patent Document 1 is used in a wide range, incident light from the light source cannot be efficiently emitted from the front surface of the light guide plate, and thus it is necessary to use a diffusion plate or a plurality of small light guide plates.

  Therefore, in view of the above-described problems, the present invention has an object to provide a light guide plate and a surface light emitting device capable of uniform illumination by suppressing the brightness of the exit surface over a wide range without using a conventional diffusion plate. It is said.

  The light guide plate according to claim 1, which is made according to the present invention to solve the above-described problems, includes a light guide plate main body on which light from a light source is incident from an end surface, and a plurality of light guide plates along the light guide direction of the light guide plate main body. A plurality of protrusions that project from the light guide plate main body so as to be arranged and project light that has been guided through the light guide plate main body, and an opposing surface that faces the light emission plate main body. In the light guide plate provided in the back of the illumination object, having a plurality of reflecting portions that are formed in a plurality of grooves arranged so as to intersect with the light guide direction and reflect the light toward the protruding portion, The ridge has a first ridge formed in a vicinity region near the end surface, and a second ridge formed in a far region farther from the end surface than the vicinity region. The number of the reflection parts facing the second ridge part is the first ridge part. And greater than the number of the reflecting section which faces, characterized in that the amount of light emitted from the second ridge portion is adapted to more than the amount emitted from the first ridge portion.

  According to the light guide plate of the present invention described in claim 1, when the light incident from the end face of the light guide plate body is guided in the light guide direction in the light guide plate body, the plurality of reflecting portions project the ridges. Is reflected toward the outside of the light guide from the protruding portion. At that time, in the far region of the light guide plate main body, the number of the reflective portions opposite to the second ridges is larger than the number of the reflective portions opposite to the first ridges in the vicinity region. The amount of light reflected at the second ridge and reflected toward the second ridge can be made larger than the amount of light toward the first ridge. Therefore, the amount of light emitted from the vicinity region of the light guide body close to the light source can be smaller than the amount of light emitted from a distant region away from the light source.

  According to a second aspect of the present invention, in the light guide plate according to the first aspect, the first ridge is formed smaller than the size of the second ridge, and the plurality of reflection portions are The light guide plate main body is formed at equal intervals on the opposing surface.

  According to the light guide plate of the present invention described in claim 2, the first protrusion is formed smaller than the second protrusion and the plurality of reflection parts are formed at equal intervals. More reflective parts can be made to oppose the 2 protrusion part than a 1st protrusion part.

  According to a third aspect of the present invention, in the light guide plate according to the first or second aspect, the relative size of the first ridge portion and the second ridge portion is the light emission side of the light guide plate main body. The illuminance in the vicinity area and the far area is set to be substantially the same.

  According to the light guide plate of the present invention described in claim 3 above, the relative sizes of the first protrusion and the second protrusion are determined based on the illuminance in the vicinity region and the distant region on the exit side of the light guide plate body. Is set to be substantially uniform, the amount of light emitted to the outside from the vicinity region and the far region of the light guide plate body can be made uniform.

  The surface light-emitting device according to claim 4 made according to the present invention in order to solve the above-described problem, the light guide plate according to any one of claims 1 to 3, a light source disposed on an end surface of the light guide plate, It is characterized by having.

  According to the surface light-emitting device of the present invention described in claim 4, the light emitted from the light source enters the light guide plate from the end surface, is reflected to the exit side by each of the plurality of reflecting portions, and is outside the light guide plate. It is injected. At that time, light can be emitted with a uniform amount of light from the vicinity region and the far region of the light guide plate.

  As described above, according to the light guide plate of the present invention described in claim 1, the number of the reflective portions facing the second protrusions in the far region of the light guide plate main body is set to the first protrusions in the vicinity region. Since the amount of light emitted from the vicinity of the light guide body close to the light source can be less than the amount of light emitted from a distant region away from the light source, The amount of light emitted from the emission surface can be made uniform. Therefore, it is possible to perform uniform illumination without spots by suppressing the brightness of the exit surface over a wide range including the near and far regions without using a diffusion plate as in the prior art.

  According to the light guide plate of the present invention described in claim 2, in addition to the effect of the invention described in claim 1, the first protrusion is formed to be smaller than the size of the second protrusion, and a plurality of reflection portions Are formed at equal intervals, so that more reflecting portions can be opposed to the second ridge portion than the first ridge portion. Therefore, the amount of light emitted from the second ridge portion is reduced to the first ridge portion. Can be more than part. Further, the amount of light emitted can be adjusted according to the size of the first and second protrusions.

  According to the light guide plate of the present invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the relative sizes of the first protrusion and the second protrusion are guided. Since the illuminance in the vicinity area and the far area on the exit side of the optical plate body is set to be substantially uniform, the amount of light emitted to the outside from the near area and the far area of the light guide plate body can be made more uniform.

  As described above, according to the surface light emitting device of the present invention described in claim 4, uniform illumination without unevenness is achieved without using a diffuser plate and suppressing the brightness of the exit surface over a wide range including the near and far regions. Since a light guide plate that can be used is used, a point light source can be used, so that the cost of the apparatus can be reduced. In addition, since a wide range can be illuminated by the light guide plate, it can contribute to an increase in the size of a display device or the like.

  Hereinafter, an embodiment of a light guide plate and a surface light emitting device according to the present invention will be described below with reference to the drawings of FIGS.

  In FIG. 1, the surface light emitting device 1 includes a light guide plate 10 and a light source 20. The surface light emitting device 1 is provided behind various displays such as a dial of a vehicle instrument, a liquid crystal panel, and the like. In this embodiment, a case where the surface light emitting device 1 is provided behind a substantially circular dial (not shown) and used as a backlight will be described.

  As is well known, the dial plate is formed in a plate shape by a translucent member, and the surface of the dial plate is covered with a non-translucent member other than indices such as scales and numerals. Then, by transmitting the light emitted from the surface light emitting device 1 from the back surface of the dial, the indicator is emitted by the transmitted light.

  The light guide plate 10 includes a light guide plate main body 11, a plurality of protrusions 12, and a plurality of reflection portions 13.

  The light guide plate body 11 is formed in a substantially plate shape, for example, with a light-transmitting acrylic resin, polycarbonate resin, or the like. The outer shape of the light guide plate body 11 is formed in a substantially ring shape similar to that of the dial plate, and is formed in a shape similar to the outer shape of the illumination object. The light guide plate body 11 is disposed behind the dial so that the light source 20 faces the end surfaces 11a on both sides. The light guide plate main body 11 guides light incident from the light source 20 toward the light guide direction X.

  In the present embodiment, the light guide plate main body 11 is formed around the target center line C. In the light guide plate main body 11, a region away from the end surface 11a by a predetermined distance is a neighborhood region E1 in the vicinity of the end surface 11a, and a region from the neighborhood region E1 to the target center line C is from the end surface 11a to the neighborhood region E1. It is set as a far region E2 that is further away from the center. In addition, about the setting of the near region E1 and the far region E2, it can set suitably according to the brightness | luminance of the light source 20, the dimension of the light-guide plate main body 11, an external shape, etc., for example.

  Each of the plurality of protrusions 12 is formed in a lens shape protruding toward the exit surface 11 b side of the light guide plate body 11 so that a plurality of the protrusions 12 are arranged along the light guide direction X of light in the light guide plate body 11. That is, the plurality of protrusions 12 are formed on the exit surface 11 b as arcuate rows extending in the light guide direction X. And in this embodiment, as shown in FIG. 1, although the case where the several protrusion part 12 forms 6 rows along the light guide direction X is demonstrated, this invention is not limited to this, injection | emission It can be designed in consideration of the amount of light emitted from the surface 11b.

  As shown in FIGS. 2 and 3, the protrusion 12 has a substantially triangular cross section in a direction intersecting the light guide direction X so as to emit light guided through the light guide plate body 11. The protruding portion 12 has an exit surface 12a, and the exit surface 12a is an inclined surface that projects from the exit surface 11b of the light guide plate body 11 so that light reflected by the reflector 13 described later is transmitted. . That is, the exit surface 12a reduces reflected light from being internally reflected by the exit surface 11b. Therefore, the amount of light emitted to the outside from the exit surface 11b is larger than the amount of light emitted to the outside from the surrounding exit surface 11b. In addition, the cross-sectional shape of the protrusion part 12 is not limited to the substantially triangular shape of this embodiment, For example, it can be set as various cross-sectional shapes, such as a circular arc, a semicircle, and a square.

  The ridges 12 are formed in a plurality of first ridges 121 formed in the vicinity region E1 in the vicinity of the end surface 11a of the light guide body 11, and in a far region E2 away from the end surface 11a than the vicinity region E1. And a plurality of second protrusions 122 formed. The first ridge 121 is formed smaller than the size of the second ridge 122. That is, the relative sizes of the first protrusion 121 and the second protrusion 122 are set so that the illuminances of the near area E1 and the far area E2 on the light exit surface 11b side of the light guide plate body 11 are substantially the same. Has been.

  In the present embodiment, each of the plurality of first protrusions 121 has the same size in the vicinity region E1, and each of the plurality of second protrusions 122 has the same size in the far region E2. It has become. However, when it is necessary to change the amount of light emitted in each region, for example, the size is gradually increased from the side closer to the light source 20, and a plurality of types of sizes are arranged in arbitrary patterns. It can be in the form. In the embodiment as well, the size of the first protrusion 121 is smaller than that of the second protrusion 122.

  As shown in FIGS. 2, 4, and 5, each of the plurality of reflecting portions 13 is arranged in a row so as to intersect the light guide direction X on the facing surface (bottom surface) 11 c facing the exit surface 11 b side of the light guide plate body 11. It has a reflective surface 13 a that is formed in a groove shape and reflects light guided inside the light guide plate body 11 toward the ridge 12. The reflecting portion 13 is formed on the facing surface 11c of the light guide plate body 11 as a groove having a substantially V-shaped cross section. The plurality of reflecting portions 13 are formed at equal intervals on the opposing surface 11c in the light guide direction X, and the intervals are arbitrarily designed according to the amount of reflected light reflected toward the ridge portion 12, and the like. The

  In addition, although this embodiment demonstrates the case where the some reflection part 13 is arrange | positioned at equal intervals, this invention is not limited to this, For example, the space | interval of the some reflection part 13 is narrowed in the near region E1. However, various embodiments can be made such as widening the distance in the far region E2.

  As shown in FIGS. 4 and 5, the light guide plate 10 having the configuration described above has a plurality of reflecting portions 13 formed at equal intervals, but the size of the first protrusion 121 (the length in the light guide direction X). ) Is formed to be smaller than the second ridge 122, as shown in FIG. 4, one reflecting portion 13 faces the first ridge 121, and as shown in FIG. The three reflecting portions 13 are opposed to the second protrusion 122. Therefore, the amount of light reflected toward the first ridge 121 is less than the amount of light reflected toward the second ridge 122.

  As the light source 20, an LED (light emitting diode), a bulb, or the like is arbitrarily used. The light source 20 is mounted on the printed board 30, and is positioned so as to face the end surface 11 a of the light guide plate body 11 by the printed board 30. The light source 20 is controlled to be turned on / off by a control unit (not shown) mounted on the printed circuit board 30.

  Next, an example of the operation (action) according to the present invention of the surface light emitting device 1 having the above-described configuration will be described below with reference to the drawings of FIGS.

  When activated, the surface light emitting device 1 turns on the light source 20. Then, the light emitted from the light source 20 enters the light guide plate body 11 from the end surface 11 a of the light guide plate 10 and is guided in the light guide direction X in the light guide plate body 11. First, in the vicinity region E1 of the light guide plate body 11, as shown in FIG. 4, the lights L1 and L3 are reflected toward the first protruding portion 121 by the reflecting surface 13a of the reflecting portion 13, and The light is emitted from the light emission surface 12 a toward the outside of the light guide 10. The light L2 is reflected by the reflecting surface 13a of the reflecting portion 13 toward the exit surface 11b of the light guide body 11, and part of the light L2 is emitted from the exit surface 11b toward the outside of the light guide 10. Is internally reflected by the exit surface 11 b and guided through the light guide plate body 11.

  Further, in the far region E2 of the light guide plate body 11, the light L4 to L6 is reflected toward the second projecting portion 122 by the reflecting surface 13a of the reflecting portion 13 as shown in FIG. The light is emitted from the light emission surface 12 a toward the outside of the light guide 10. Therefore, since the 1st protrusion 121 is formed in the short protrusion, the light inject | emitted on the emission surface 11b side of the light-guide plate 10 compared with the 2nd protrusion 122 with which all the short protrusions were connected. Decrease.

  Thereby, the light emitted to the front surface of the light guide plate 10 near the light source 20 that tends to be bright can be reduced, and the brightness can be suppressed to the same brightness as that of the emission surface 11 b away from the light source 20. Further, by changing the length of the protrusion 12, it is possible to control the brightness of the emitted light to match the brightness away from the light source 20, so that the light emitted from the light guide plate 10 is uniform. Can be. Therefore, the dial, which is the object to be illuminated by the surface light emitting device 1, transmits the light emitted by the surface light emitting device 1, thereby causing the transmitted light to emit an indicator.

  According to the light guide plate 10 described above, the number of the reflective portions 13 that face the second protrusion 122 in the remote region E2 of the light guide plate body 11 is opposite to the first protrusion 121 in the vicinity region E1. Since the number of reflection parts 13 is increased, the amount of light emitted from the vicinity region E1 of the light guide body 11 close to the light source 20 can be smaller than the amount of light emitted from the far region E2 away from the light source 20, The amount of light emitted from the exit surface 11b of the optical plate 10 can be made uniform. Therefore, it is possible to perform uniform illumination without unevenness by suppressing the brightness and darkness of the exit surface 11b over a wide range including the near region E1 and the far region E2 without using a diffusion plate as in the prior art.

  Moreover, since the 1st protrusion part 121 is formed smaller than the magnitude | size of the 2nd protrusion part 122, and the some reflection part 13 is formed at equal intervals, the 2nd protrusion part 122 has a 1st protrusion part in it. Since more reflection parts 13 can be made to oppose than the part 121, the light quantity inject | emitted from the 2nd protrusion part 122 can be increased more than the 1st protrusion part 121. FIG. Further, the amount of light emitted can be adjusted according to the size of the first ridge 121 and the second ridge 122.

  Furthermore, the relative sizes of the first protrusion 121 and the second protrusion 122 are set so that the illuminances of the near area E1 and the far area E2 on the exit side of the light guide plate body 11 are substantially uniform. Since it did in this way, the light quantity inject | emitted outside from the near region E1 and the far region E2 of the light-guide plate main body 11 can be made more uniform.

  Moreover, according to the surface light-emitting device 1, it has the light-guide plate 10 which can suppress the brightness and darkness of the emission surface 11b over a wide range including the near region E1 and the far region E2 and can perform uniform illumination without using a conventional diffuser plate. Since it did in this way, since a point light source can be used, the cost reduction of an apparatus can be aimed at. Moreover, since the light guide plate 10 can illuminate a wide area, it can contribute to enlargement of a display device or the like.

  In the present embodiment described above, as shown in FIG. 1, the first protrusion 121 and the second protrusion 122 have the same size in each of the near region E1 and the far region E2 of the light guide plate 10. Although the case has been described, the present invention is not limited to this. For example, as shown in FIG. 6, the first ridge 121 and the second ridge from the vicinity of the light source 20 from the vicinity region E1 to the far region E2. 122 is formed so as to gradually increase gradually, the second protrusion 122 is formed gradually larger from the light source 20 only in the far region E2, or gradually increased from the light source 20 in stages. Different embodiments can be provided.

  Moreover, although this embodiment mentioned above demonstrated the case where the light-guide plate 10 was formed in substantially ring shape, this invention is not limited to this, For example, it is set as various shapes, such as a square, a rectangle, and a fan shape. be able to. Even in that case, by setting the vicinity 12 of the light source 20 as the near region E1, and the far region as the far region E2, and arranging the protrusion 12 and the reflection part 3 described above, the above-described effects can be obtained. Can do.

  In addition, although this embodiment mentioned above demonstrated the case where the illumination target object of the surface emitting device 1 was the said dial, this invention is not limited to this, For example, a liquid crystal panel, a lighting fixture, etc. It can be set as various different embodiments, such as making it an illumination object.

  As described above, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a perspective view which shows schematic structure of the light-guide plate and surface emitting device of this invention. It is the enlarged view which expanded only the light-guide plate in the part A in FIG. It is the enlarged view to which the part B of the light-guide plate in FIG. 1 was expanded. It is a figure for demonstrating the relationship between the 1st protrusion part and reflection part in the vicinity area | region of the light-guide plate in FIG. It is a figure for demonstrating the relationship between the 1st protrusion part and reflection part in the vicinity area | region of the light-guide plate in FIG. It is a perspective view which shows the other example of schematic structure of the light-guide plate and surface emitting device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface light-emitting device 10 Light guide plate 11 Light guide plate main body 12 Projection part 13 Reflection part 20 Light source 121 First protrusion 122 Second protrusion E1 Near field E2 Far field X Light guide direction

Claims (4)

A light guide plate body in which light from a light source is incident from an end surface; and a plurality of light guide plates that are arranged along the light guide direction X of the light in the light guide plate body. A plurality of protrusions for emitting light guided in the light plate main body, and a plurality of grooves formed in a plurality of rows so as to cross the light guide direction on an opposing surface facing the light emission side of the light guide plate main body and the light A light guide plate provided behind the object to be illuminated,
The ridge has a first ridge formed in a vicinity region near the end surface, and a second ridge formed in a far region farther from the end surface than the vicinity region. ,
Increasing the number of the reflective portions opposed to the second ridge portion to be larger than the number of the reflective portions opposed to the first ridge portion, the amount of light emitted from the second ridge portion is A light guide plate characterized in that the amount of light emitted from the first protrusion is greater than the amount of light emitted from the first protrusion. The first protrusion is formed smaller than the size of the second protrusion, and
The light guide plate according to claim 1, wherein the plurality of reflecting portions are formed at equal intervals on a facing surface of the light guide plate main body.   The relative sizes of the first protrusion and the second protrusion are set so that the illuminance in the vicinity area and the distant area on the exit side of the light guide plate body is substantially the same. The light guide plate according to claim 1 or 2.   A surface light emitting device comprising: the light guide plate according to claim 1; and a light source disposed on an end surface of the light guide plate.

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