JP2005293956A - Surface light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the waste of light emitted from a light source, to effectively utilize the emitted light, and to increase a luminance value on a liquid crystal panel and a liquid crystal contrast. <P>SOLUTION: A surface light source device is provided with: at least light incidence surface; a light guide plate, having a light emission surface for emitting incidence light from the light incidence surface in a planar shape; a reflection member arranged at a surface side opposite to the light emission surface of the light guide plate; an optical member arranged at the light emission surface side of the light guide plate; and the light source for emitting light toward the light incidence surface of the light guide plate. The upper portion of the light emission surface of the light guide plate arranged in the case is covered with a chassis having an opening, and a dustproof member containing a light reflecting substance is provided at the light emission surface side of the chassis. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface light source device.

  The surface light source device includes a direct type and a side light type depending on the arrangement position of the light source. In the present invention, a side light type surface light source device that is generally used will be described. FIG. 5 is an exploded perspective view showing a basic structure of a conventional sidelight type surface light source device, and FIG. 6 is a cross-sectional view seen from the direction of arrow A in FIG. Reference numeral 1 denotes a light source, for example, a light emitting diode (LED). The light source 1 is mounted on a flexible substrate 8, and the flexible substrate 8 on which the light source 1 is mounted is fixed to a side end portion (light incident surface) of the light guide plate 3 with a double-sided tape 7.

  Reference numeral 5 denotes a case, in which the reflecting member 2 is disposed at the bottom of the case 5, and the light guide plate 3 is disposed on the reflecting member 2. The light source 1 is disposed on the light incident surface side of the light guide plate 3, and the optical member 4 is disposed on the light exit surface side of the light guide plate 3. Reference numeral 6 denotes a chassis having an opening light emitting area 9, which covers the light emitting surface side of the light guide plate 3 in correspondence with the opening light emitting area 9, and a dustproof member on the light emitting surface side peripheral portion of the opening light emitting area 9. 10 is arranged to constitute a side light type surface light source device.

  The reflection member 2 is formed in a sheet shape, and is a member having a high reflectance. For example, a metal particle such as silver is vapor-deposited on a polyester, polyolefin, or resin sheet.

  The optical member 4 is formed by laminating several kinds of sheet-like members. In FIGS. 5 and 6, a diffusion sheet, a vertical prism sheet, and a horizontal prism sheet are stacked in this order on the light output surface of the light guide plate 3. Is arranged.

  The dustproof member 10 is formed in a frame shape and is a member having dustproofness and shock absorption. The dust-proof member 10 is obtained by processing foam rubber or foam polyurethane into a desired shape, for example.

  The above-described sidelight type surface light source device includes a reflective member 2 (upper reflective surface) having a high reflectance on the surface side (the lower surface side of the light guide plate 3) facing the light emitting surface of the light guide plate 3 housed in the case 5. ), The light emitted from the light source 1 passes through the light guide plate 3 while being reflected upward by the reflecting member 2. The light launched from the light guide plate 3 passes through the optical member 4 to be adjusted in the emission direction, and is emitted from the opening light emitting area 9 of the chassis 6 to the outside. This device is used as a surface light source device of a liquid crystal display device (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2002-229022 (pages 5 to 6, FIG. 1)

  In the sidelight type surface light source device shown in the background art, a part of light emitted from the light guide plate 3 at the light emitting slope side of the chassis 6 at the periphery of the light opening light emitting area 9 (inside the rectangular frame of the dustproof member 10). However, it may be absorbed by the dust-proof member 10 or transmitted to the outside to be wasted. As a result, there is a problem that the luminance on the liquid crystal panel cannot be increased without effectively using light and the liquid crystal contrast is decreased. In particular, in the small surface light source device, since the light emitting area is small, the ratio of the amount of light that collides with the dust-proof member out of the total amount of light emitted from the light emitting area of the light opening is increased. It was.

  An object of the present invention is to eliminate the waste of light emitted from a light source, effectively use the emitted light, and improve the luminance value and the liquid crystal contrast on the liquid crystal panel.

  A light guide plate having at least a light incident surface and a light emitting surface that emits light incident from the light incident surface in a planar shape, and a reflecting member disposed on a surface facing the light emitting surface of the light guide plate An optical member disposed on the light emitting surface side of the light guide plate, and a light source that emits light toward the light incident surface of the light guide plate, and the light guide plate disposed in the case. The surface light source device is configured by covering a chassis having an opening above the light emitting surface, and providing a frame-shaped dustproof member containing a light reflective material on the light emitting surface side of the chassis.

  The light guide plate, a reflecting member disposed on the surface facing the light exit surface of the light guide plate, an optical member disposed on the light exit surface side of the light guide plate, and toward the light incident surface of the light guide plate A light source that emits light is disposed in a case, and a chassis having an opening is placed over the light emitting surface of the light guide plate disposed in the case, and light reflection is performed on the light emitting surface side of the chassis. The surface light source device is provided with a frame-shaped dustproof member in which the active substance is attached only to the inner surface.

  Since a frame-shaped dust-proof member containing a light-reflective material is provided at the peripheral portion of the light emitting area of the opening on the light emitting surface side, the light emitted from the light source is eliminated, and the emitted light is used effectively. The brightness value and the liquid crystal contrast can be improved.

  A frame-shaped dust-proof member with a light-reflective material attached only to the inner surface is provided at the periphery of the light-emitting area on the light-emitting surface side, eliminating waste of light emitted from the light source and effectively using the emitted light It is possible to improve the luminance value and the liquid crystal contrast on the liquid crystal panel.

  By adopting a structure in which a frame-shaped dust-proof member containing a light-reflective material is provided at the periphery of the light-emitting area of the opening, light that was previously absorbed by the dust-proof member itself and wasted is returned to the light-emitting area. By reusing it, the brightness value and liquid crystal contrast on the liquid crystal panel were improved.

  FIG. 1 is an exploded perspective view showing a side light type surface light source device according to a first embodiment of the present invention. 2 is a cross-sectional view seen from the direction of arrow A in FIG. Parts similar to those of the conventional configuration will be described using the same reference numerals (hereinafter the same). Reference numeral 1 denotes a light source, for example, a light emitting diode (LED). The light source 1 is mounted on a flexible substrate 8, and the flexible substrate 8 on which the light source 1 is mounted is fixed to the side end (light incident surface) side of the light guide plate 3 with a double-sided tape 7.

  Reference numeral 5 denotes a case, in which the reflecting member 2 is disposed at the bottom of the case 5, and the light guide plate 3 is disposed on the reflecting member 2. The reflecting member 2 is a sheet-like member, for example, obtained by evaporating metal particles such as silver on a polyester, polyolefin, or resin sheet. A light source 1 is disposed on the light incident surface side of the light guide plate 3, and an optical member 4 is disposed on the light exit surface side of the light guide plate 3. The optical member 4 is formed, for example, by laminating sheet-like members in the order of a diffusion sheet, a vertical prism sheet, and a horizontal prism sheet from the light emitting surface side of the light guide plate 3. Reference numeral 6 denotes a chassis having an opening light emitting area 9, which covers the light emitting surface side of the light guide plate 3 in correspondence with the opening light emitting area 9, and a dustproof member on the light emitting surface side peripheral portion of the opening light emitting area 9. 11 is arranged to constitute a side light type surface light source device. The dust-proof member 11 is, for example, a rectangular frame shape (in this embodiment, a rectangular shape by adding a light-reflective substance (not shown) to foamable rubber or foamable polyurethane, but the present invention relates to the shape of the frame. (The same applies hereinafter).

  In the side light type surface light source device having the above configuration, the light emitted from the light source 1 passes through the light guide plate 3 while being reflected upward by the reflecting member 2. Most of the light raised from the light guide plate 3 passes through the optical member 4 so that the light emission direction is adjusted, and is emitted from the opening light emitting area 9 to the outside of the sidelight type surface light source device. At this time, a part of the outgoing light passing through the rectangular frame of the dust-proof member 11 and having an angle from the light-emitting surface is reflected inward by the light-reflecting substance contained in the dust-proof member 11. The light reflected thereby is repeatedly reflected within the rectangular frame of the dust-proof member 11 and reused. With this configuration, light is not wasted, the amount of light is increased, and the luminance value and the liquid crystal contrast on the liquid crystal panel can be improved.

  The dust-proof member 11 containing the light-reflective material is a material in which a light-reflective material is dispersed in a foamed rubber or foamed urethane substrate, and reflects light that has entered the dust-proof member by the light-reflective material. By doing so, there is an advantage that the amount of light absorbed by the dustproof member itself and the amount of light transmitted through the dustproof member can be greatly reduced. Further, the dustproof member 11 which is a foam can be said to enhance the light reflection effect because the foamed structure becomes dense when the surface emitting source device is pressed when the liquid crystal panel is attached.

  FIG. 3 is an exploded perspective view showing a side light type surface light source device according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view seen from the direction of arrow A in FIG. In the second embodiment, the light-reflecting material layer 12a is formed so as to adhere only to the inner surface of the rectangular frame-shaped dustproof member shown in the first embodiment to constitute a sidelight type surface light source device.

  The light emitted from the light source 1 passes through the light guide plate 3 while being reflected upward by the reflecting member 2. Most of the light raised from the light guide plate 3 passes through the optical member 4 so that the light emission direction is adjusted, and is emitted from the opening light emitting area 9 to the outside of the sidelight type surface light source device. At this time, out of the emitted light passing through the inside of the rectangular frame of the dust-proof member 12 (in this embodiment, it is rectangular, but the present invention can be applied regardless of the shape of the frame; the same applies hereinafter), from the light emitting surface. A part of the light having an angle is reflected inward by the light-reflecting material layer 12 a attached only to the inner surface of the dust-proof member 12. The light reflected thereby is repeatedly reflected within the rectangular frame of the dustproof member 12 and reused. With this configuration, light is not wasted, the amount of light is increased, and the luminance value and the liquid crystal contrast on the liquid crystal panel can be improved.

  The rectangular dust-proof member 12 in which the light-reflective material 12a is attached only to the inner surface is a method of attaching a white reflective polyester layer to the base surface of foamable rubber or foamable urethane, or deposits metal particles such as silver. Formed by the method. A light-reflective material layer 12a is formed on the inner surface of the rectangular dust-proof member 12 that is a foam, and the light that collides with the inner surface of the rectangular dust-proof member 12 is reflected to be absorbed by the dust-proof member itself. This has the advantage of reducing the amount of light transmitted or transmitted. In addition, since the light-reflective material 12a is attached only to the necessary portion (inner surface) of the rectangular dust-proof member 12, it is difficult to impair other characteristics (dust-proof and shock-absorbing properties) of the dust-proof member 12. There are advantages. Further, the dust-proof member 12 which is a foam can be said to further enhance the light reflection effect because the foamed structure becomes dense when the surface emitting source device is pressed when the liquid crystal panel is attached.

An exploded perspective view showing a surface light source device having a dustproof structure of the present invention (Example 1) Sectional view seen from the direction of arrow A in FIG. 1 (Example 1) An exploded perspective view showing a sidelight type surface light source device of the present invention (Example 2) Sectional view seen from the direction of arrow A in FIG. 3 (Example 2) An exploded perspective view showing a basic structure of a conventional sidelight type surface light source device Sectional view seen from the direction of arrow A in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Reflective member 3 Light guide plate 4 Optical member 5 Case 6 Chassis 7 Double-sided tape 8 Flexible substrate 9 Opening light emission area 10 Dust-proof member 11 Dust-proof member 12 containing light-diffusion substance Dust-proof member 12a Light-reflective material layer

Claims (2)

  A light guide plate having at least a light incident surface and a light emitting surface that emits light incident from the light incident surface in a planar shape, and a reflecting member disposed on a surface facing the light emitting surface of the light guide plate An optical member disposed on the light emitting surface side of the light guide plate, and a light source that emits light toward the light incident surface of the light guide plate, and the light guide plate disposed in the case. A surface light source device comprising a chassis having an opening above a light emitting surface, and a frame-shaped dustproof member containing a light-reflective material provided on the light emitting surface side of the chassis. The light guide plate, a reflecting member disposed on the surface facing the light exit surface of the light guide plate, an optical member disposed on the light exit surface side of the light guide plate, and toward the light incident surface of the light guide plate A light source that emits light is disposed in a case, and a chassis having an opening is placed over the light emitting surface of the light guide plate disposed in the case, and light reflection is performed on the light emitting surface side of the chassis. The surface light source device according to claim 1, further comprising a frame-shaped dustproof member in which the active substance is attached only to the inner surface.

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