JP2007214076A - Surface light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface light emitting device capable of obtaining uniform surface emission output having a high luminance. <P>SOLUTION: This surface light emitting device has an almost plate-like light guide plate to derive light to its one main surface, a groove part formed on the side of the light guide plate, and a light emitting diode element at least a part of which is inserted in the groove part to emit light in the in-plane direction of the main surface of the light guide plate. Since the groove part is formed on the side of the guide plate, the light emitting diode element serving as a light source can be inserted into the inside of the groove. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface light-emitting component that emits light to a diffusion plate member having a light-emitting surface, and a surface light-emitting device that is configured by collecting such surface light-emitting components.

  Recently, as a light source for a backlight of a liquid crystal display device, a light emitting diode element (LED) or a cold cathode tube is used to generate light, and light from the light emitting diode element or the cold cathode tube is emitted in a planar shape. The device is used. In such a surface light-emitting device, light-emitting diode elements and the like are usually arranged on one side surface of the light guide plate, and the light incident from the side surface is reflected by one main surface of the light guide plate and faces the opposite side. Ejected from the main surface. A plurality of dots for reflection are formed on one main surface of the light guide plate that performs reflection, and light incident from the side surface is reflected by the plurality of dots to the exit surface.

  As a light guide plate on which such dots for reflection are formed, the dots are arranged so that a band-like area defined as an area having a certain distribution density is formed, and the interval formed by the dots in each band-like area is set. A technique is known in which generation of bright lines is suppressed by setting the area different from the adjacent band-like areas (see, for example, Patent Document 1). As a light diffusing dot pattern on the reflection surface of the light guide plate, a technique is also known in which the area of the dots is sequentially enlarged as the distance from the light source increases, and the area for light diffusion in a region further away from the light source is increased. (For example, refer to Patent Document 2). Further, there is also known a configuration in which a light guide plate itself having a slope is used so that light incident from the side surface can be reflected at a dispersed position on the exit surface and the entrance surface (see, for example, Patent Document 3). .) In addition, there is also known a technique of forming a V-shaped groove that is thin at the central portion to solve the problem that light does not reach the central portion (see, for example, Patent Document 4).

JP 2003-43266 A JP-A-8-271893 JP-A-6-314069 JP 2001-228477 A

  Stable light guide is possible by using the light guide plate, and when the parts are assembled, the light guide plate is located at the center of the part that covers the assembly. For example, the parts are aligned with the end face or surface of the light guide plate. It is possible to improve the assembly accuracy. However, when using a surface emitting device for a relatively large signboard, it is necessary to shine the entire large signboard, so a large-sized light guide plate is indispensable, especially when a large-sized light guide plate is used Then, there also arises a problem that the light amount is insufficient in the central portion that is far from the light source. In general, when a light-emitting diode element is used as a light source, there is a strong directivity in the direction of light emitted from the light-emitting diode element. There has been a need to improve the diffusion of light inside the light guide plate.

  Accordingly, an object of the present invention is to provide a surface light-emitting device that can solve various problems in the conventional surface light-emitting device and obtain a uniform and high-luminance surface light-emitting output.

  In order to solve the above-described technical problem, the surface light-emitting device of the present invention includes a substantially plate-shaped light guide plate that guides light to one main surface, a groove formed on a side surface of the light guide plate, And a light emitting diode element that emits light in an in-plane direction of the main surface of the light guide plate, at least part of which is inserted into the groove. By forming the groove on the side surface of the light guide plate, a light emitting diode element serving as a light source can be inserted into the groove.

  According to a preferred embodiment of the present invention, the shape of the light introducing portion of the groove is set to a shape that functions as a lens. As a shape that functions as a lens, in addition to a lens such as a concave lens or a convex lens, a Fresnel lens or the like can be provided, or a minute prism sheet can be attached. By providing the groove with the lens function, the light from the light emitting diode element can be refracted at the interface of the light introduction part of the groove to widen the reach of the light, and a uniform surface emission distribution can be obtained over a wide area. Can produce light.

  Further, the light introducing portion of the groove portion can be matted, for example, and the matting can diffuse the light in the light introducing portion, and the light can be guided in a wide range over the entire light guide plate. It can be introduced into the light plate. A light emitting diode element is formed in each groove formed on the side surface of the light guide plate. However, the present invention is not limited to the case where one light emitting diode element is formed in one groove, and a plurality of light emitting diode elements are mounted in one groove. It can also be set as a structure. In this way, the plurality of light emitting diode elements may be, for example, two, three or more white diodes arranged side by side, such as red, blue, green, etc. It is also possible to combine and mount diodes of different sizes and shapes in the same groove.

  According to a preferred embodiment of the present invention, the gap between the light emitting diode element inserted into the groove and the groove is filled with an adhesive layer containing a fluorescent material, for example. Furthermore, it is possible to configure the outer portion of the light emitting diode element to fit in the groove. In addition, a plurality of reflective dots may be formed on the surface of the light guide plate that faces the main surface from which light is emitted, and the shape of the reflective dots is not particularly limited. It is a quadrangular pyramid-shaped recess formed on the back surface of the light-emitting diode, and it is also possible to arrange it uniformly in a matrix shape, but the luminance tends to decrease at a position far from the light-emitting diode element. It is also possible to arrange the reflective dots densely at a distant position so that the luminance of the main surface of the light guide plate is made uniform as a whole. Further, the shape of the reflective dot is not limited to the quadrangular pyramid shape, and may be a triangular pyramid shape, a hexagonal pyramid shape, other polygonal pyramid shapes, a cone, a cylinder, a non-standard concave portion, or the like, and protrudes from the back surface. A reflective dot having such a shape may be used.

  According to the surface light-emitting device of the present invention, by forming a groove on the side surface of the light guide plate, a light-emitting diode element serving as a light source can be inserted into the groove, and a range in which light can reach through the groove is reduced. It is possible to generate light having a uniform surface emission distribution over a wide area. Therefore, light with uniform and sufficient surface distribution can be obtained over a wide range of the light guide plate, and light with ideal surface distribution is output.

  A preferred embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic plan view of a surface light emitting device according to this embodiment, which includes a flat light guide plate 10 made of a transparent acrylic resin and having a required thickness. The back surface side of the light guide plate 10 is a reflective dot region 11 in which a plurality of reflective dots for reflecting light incident from the side surface 15 side to the front surface side of the light guide plate 10 is formed. It is formed so as to extend over the entire back surface of the optical plate 10. On the back side of the light guide plate 10, a reflection plate (not shown) or the like can be provided so as to face the reflection dot region 11. When such a reflection plate is provided, the reflected light from the reflection plate and the reflection dot The light reflected by the light is emitted toward the surface 12 side, which is one main surface of the light guide plate 10.

  The side surface 15 of the light guide plate 10 having such a reflective dot region 11 is formed with a plurality of recesses 14 as groove portions, and the light emitting diode elements 13 each having a shell-shaped package with respect to the recesses 14 are respectively provided. The light emitting diode element 13 emits light in the in-plane direction of the main surface of the light guide plate 10. The concave portion 14 is shaped to draw an arc in a horizontal section from the side surface 15 of the light guide plate 10, and functions as a concave cylindrical lens whose axial direction is the thickness direction of the plate. The substantially central portion of the concave portion 14 is a light introducing portion 16. When light from the light emitting diode element 13 passes through the light introducing portion 16, a gap and the concave portion 14 are formed between the light emitting diode element 13 and the concave portion 14. The light from the light emitting diode element 13 functions so as to spread by refraction at the interface between the light guide plates 10, and a wide range of reflective dot regions 11 can be irradiated by one light emitting diode element 13. The light introducing portion 16 in the groove portion can be matted, for example, and the matting can further diffuse the light in the light introducing portion 16, so that light can be transmitted over the entire light guide plate 10. The light guide plate 10 can be introduced in a wide range. The package of the light emitting diode element 13 can be matted. 1 and 2 and the following embodiments, wiring to each light-emitting diode element is omitted, but it is assumed that a required power supply is supplied.

  According to the surface light emitting device of the present embodiment, the concave portion 14 is formed in the side surface 15 of the light guide plate 10 in this way, and the light from the light emitting diode element 13 is spread in the in-plane direction of the light guide plate 10 by the concave portion 14. Eject. Therefore, the light from the light emitting diode element 13 is diffused before the light reaches each reflective dot in the reflective dot region 11 and is output from the light guide plate 10 in a more uniform state. In particular, since a light diffusion phenomenon near the light source can be obtained, for example, the number of light emitting diode elements 13 that need to be arranged on the side surface 15 of the light guide plate 10 can be reduced, and uniform light can be output at a lower price. It is realized to provide a surface light emitting device.

  In the example shown in FIG. 1, the concave portion 14 is formed only on one side surface 15 of the flat light guide plate 10. However, such a concave portion 14 may be formed on all side surfaces of the flat light guide plate 10 or other side surfaces. You may form in a side surface. In the example shown in FIG. 1, the example in which the concave portion 14 having the same size is formed on one side surface 15 of the flat light guide plate 10 has been described. However, the size of the concave portion and the direction of the groove at the end portion and the central portion are described. It is also possible to change or arrange the groove portions of different shapes in order. Furthermore, the shape of the groove can be changed in accordance with the emission wavelength. Further, the interval between the recesses 14 may be uniform, and the interval between the recesses may be changed according to the position.

  The surface light-emitting device of this embodiment is used as a backlight device of a liquid crystal display device, for example, a device that emits light such as a large screen, a signboard, or an advertising panel, alone, a lighting device, a sign, a button, It can be applied to various crafts such as figurines, interiors, and exteriors.

[Second Embodiment]
FIG. 2 is a perspective view of a main part of the surface light emitting device according to the second embodiment. As shown in FIG. 2, a rectangular opening that forms a groove on a side surface 25 of a light guide plate 21 made of a transparent resin flat plate. 24 is formed, and on the back side of the opening 24, a convex portion 26 having a center projecting toward the near side is formed. A light emitting diode element 23 inserted through the rectangular opening 24 is disposed so as to face the convex portion 26. Thus, the groove part formed in the side surface 25 of the light guide plate 21 may have a structure including the convex part 26 as shown in FIG. 2, and even if it functions as a convex lens, it exceeds the focal point. Since the light tends to spread at the different positions, the convex portions 26 may be used for uniform light emission having a surface distribution. Further, a groove portion that is a combination of a concave lens and a convex lens may be formed, and the shape of the opening 24 is not limited to a rectangular shape, and may be a round shape or a square shape.

  In FIG. 2, the opening 24 is formed so as to cut the side surface 25. However, such an opening 24 is formed simultaneously with the formation of the light guide plate 21 when the light guide plate 21 is formed by injection molding. Alternatively, the light guide plate 21 may be formed by a separate process.

[Third Embodiment]
FIG. 3 is a schematic plan view of the surface light emitting device according to the third embodiment, and includes a flat light guide plate 30 made of a transparent acrylic resin and having a required thickness. A reflection dot region 31 is formed in which reflection dots for reflecting light incident from the side surface 36 side to the front surface side of the light guide plate 30 are formed over the entire rear surface of the light guide plate 30. In the case where the reflection plate is provided, the reflected light from the reflection plate and the light reflected by the reflection dots are emitted toward the surface 32 side which is one main surface of the light guide plate 30.

  The side surface 36 of the light guide plate 30 having such a reflective dot region 31 is formed with a plurality of concave portions 35 that are slightly wider grooves, and a pair of light emission having, for example, a shell type package for each concave portion 35. Each of the diode elements 33 and 34 is disposed so that a part of the head portion on the light emission side is inserted. The concave portion 35 is shaped to draw an arc in a horizontal section from the side surface 36 of the light guide plate 30 and functions like a concave cylindrical lens whose axial direction is the thickness direction of the plate. When light from the light-emitting diode elements 33 and 34 passes, the light-emitting diode element is refracted at the interface between the light-guiding plate 30 constituting the gap and the gap 35 between the light-emitting diode elements 33 and 34 and the concave part 35. It functions so that the light from 33 and 34 spreads, and a wide range of reflective dot regions 31 can be irradiated by the respective light emitting diode elements 33 and 34.

  According to the surface light emitting device of the present embodiment, the wide concave portion 35 is formed on the side surface 36 of the light guide plate 30 in this way, and the light from the pair of light emitting diode elements 33 and 34 is transmitted by the concave portion 35 of the light guide plate 30. Inject to spread in the in-plane direction. Therefore, the light from the light emitting diode elements 33 and 34 is sufficiently diffused before the light reaches each reflective dot in the reflective dot region 31, and is output from the light guide plate 30 in a more uniform state. In addition, since a pair of light emitting diodes 34 is formed in one concave portion 35, it is possible to cause light of different emission wavelengths to act in a complementary manner due to the relationship of wavelength regions. It is also possible to realize a display device that realizes a stereoscopic view by distinguishing a combination of light diodes in the light wavelength range, for example, a light-emitting diode for the right eye and a light-emitting diode for the left eye.

  In the example shown in FIG. 3, the pair of light emitting diode elements 33 and 34 is the same white light emitting diode element, but diodes having different luminances and light emission wavelengths may be combined and arranged in a horizontal manner as shown in the figure. Not limited to this, a plurality of light emitting diode elements may be arranged in a vertical direction or an oblique direction. Further, the number of light emitting diode elements corresponding to one recess is not limited to two, and three or four or more elements may be arranged. Further, in the example shown in FIG. 3, the concave portion 35 is formed only on one side surface 36 of the flat light guide plate 30. Such a concave portion 35 is formed on the entire side surface or other side surface of the flat light guide plate 30. You may form in.

[Fourth Embodiment]
FIG. 4 is a schematic plan view of the surface light emitting device according to the fourth embodiment, and includes a flat light guide plate 40 made of a transparent acrylic resin and having a required thickness. A reflection dot region 41 is formed on the entire rear surface of the light guide plate 40 where reflection dots for reflecting light incident from the side surface 36 side to the front surface side of the light guide plate 40 are formed. In the case where the reflection plate is provided, the light reflected from the reflection plate and the light reflected by the reflection dots are emitted toward the surface 42 side, which is one main surface of the light guide plate 40.

  A plurality of substantially rectangular recesses 44 are formed on the side surface 46 of the light guide plate 40 having the reflective dot region 41, and the light emitting diode element 43 having, for example, a shell-shaped package is provided in each recess 44 as a fluorescent material. It is arrange | positioned so that it may be embed | buried under the contact bonding layer 45 containing this. In the surface light emitting device having such a structure, the adhesive layer 45 containing a fluorescent material can increase the output light in accordance with the light output from the light emitting diode element 43, thereby further enhancing the light diffusion effect. it can.

  In the example shown in FIG. 4, an example in which the terminal side end of the light emitting diode element 43 and the side surface 46 of the light guide plate 40 are flush with each other is illustrated. However, the terminal side end of the light emitting diode element 43 is the light guide plate. It may protrude from the side surface 46 of 40 or may be recessed. Further, as shown in FIG. 3, also in this embodiment, a plurality of light emitting diode elements can be simultaneously embedded in the adhesive layer. Further, in the example shown in FIG. 4, the concave portion 44 is formed only on one side surface 46 of the flat light guide plate 40, but such a concave portion 44 may be formed on all side surfaces of the flat light guide plate 40 or other side surfaces. You may form in a side surface.

  In each of the above-described embodiments, the example in which the light emitting diode element has a shell-type package has been described. However, the present invention is not limited to the package structure of the light emitting diode element, and has a package with another structure. Also good.

It is a schematic plan view which shows the surface emitting device of the 1st Embodiment of this invention. It is a principal part perspective view of the surface emitting device of the 2nd Embodiment of this invention. It is a schematic plan view which shows the surface emitting device of the 3rd Embodiment of this invention. It is a schematic plan view which shows the surface emitting device of the 4th Embodiment of this invention.

Explanation of symbols

10, 21, 30, 40 Light guide plate 11, 31, 41 Reflective dot region 13, 23, 33, 34, 43 Light-emitting diode element 14, 35, 44 Recess 15, 25, 36, 46 Side surface 45 Adhesive layer

Claims (7)

A substantially plate-shaped light guide plate that guides light to one main surface;
A groove formed on a side surface of the light guide plate;
A surface light emitting device comprising: a light emitting diode element that is at least partially inserted into the groove and emits light in an in-plane direction of the main surface of the light guide plate. The surface light-emitting device according to claim 1, wherein the shape of the light introducing portion of the groove functions as a lens. The surface light-emitting device according to claim 2, wherein the light introducing portion is matted. 2. The surface light emitting device according to claim 1, wherein a plurality of light emitting diode elements are mounted in the groove portion. 2. The surface light emitting device according to claim 1, wherein a gap is formed between the groove and the light emitting diode element inserted in the groove. 2. The surface light emitting device according to claim 1, wherein an adhesive layer containing a fluorescent material is filled between the groove and the light emitting diode element inserted into the groove. The surface light-emitting device according to claim 1, wherein a plurality of reflective dots are formed on a surface of the light guide plate that faces the main surface that emits light.