JP4531273B2 - LIGHTING DEVICE, LIQUID CRYSTAL DISPLAY DEVICE AND DEVICE USING THE SAME - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting device used for a liquid crystal display device of a device such as a mobile phone or a portable information terminal such as a pocket PC, a liquid crystal display device using the lighting device, and a device incorporating the same.
[0002]
[Prior art]
Liquid crystal display devices are widely used from large devices such as word processors and personal computers to small devices such as mobile phones and portable information terminals developed by recent development of various information devices. FIG. 5 is a schematic cross-sectional view of the liquid crystal display device, FIG. 6 is a perspective view showing the positional relationship between the light source and the light guide in the liquid crystal display device, and 8 and 9 are small incandescent bulbs, LEDs, etc. A light source, 17 is a rectangular parallelepiped light guide made of a translucent resin material, 18 is a light reflecting plate disposed on the lower surface side of the light guide, and 19 is disposed on the upper surface of the light guide 17 to guide light. A light control member 20 for controlling the direction of light emitted from the body, 20 is a circuit board on which light sources 8, 9 and other circuit components are attached. The lower surface of the light guide 17 itself is provided with known dot pattern printing and protrusions on the entire surface so that light incident on the light guide is emitted as uniformly as possible to the entire light guide. Further, the light control member 19 may be a light diffusing plate alone, or a light diffusing plate and a prism sheet may be superposed. When the apparatus is incorporated into an actual device, a light reflector or light reflector is provided around the light source so as to surround the light source so that the light from the light source is effectively incident on the light guide.
[0003]
In the apparatus having the above configuration, when the light sources 8 and 9 emit light, the light is incident from one side surface of the light guide 17 and guided through the light guide toward the other side surface. The light that has passed from the lower surface of the light body is emitted again from the upper surface of the light guide body 17 while being incident on the light guide body again, and the direction of the light is controlled by the light control member and the light control member 19 Light is emitted from the top surface. This light is used to illuminate a liquid crystal display element (not shown) from the back and recognize an image of the liquid crystal display element.
[0004]
[Problems to be solved by the invention]
In the above conventional lighting device, the light sources 8 and 9 are arranged close to the side surface of the light guide, and the light guide emits light as uniform as possible from the upper surface by the pattern and protrusions on the lower surface of the light guide. However, when the light sources 8 and 9 are turned on, extremely dark shadows 10, 11 and 12 as shown in FIG. 7 are generated in the vicinity of the light guide where the light sources 8 and 9 are arranged. The shadows 10, 11, and 12 adversely affect the reproduced image and information of the liquid crystal display element. In order to remedy this problem, as shown in FIG. 8, a light guide body 21 in which light sources 8 and 9 are arranged is provided with an incident light adjusting portion for depressions 22 and 23. By providing the incident light adjusting sections 22 and 23, the shadows 10, 11 and 12 described above are still generated as shown in FIG. 9, but the size is small and the density is thin, and the shadow is practically used. It is improved to the extent that there is no problem. However, there is a problem that the luminance of the portion of the light emitting surface R that occupies most of the upper surface of the light guide 21 is lowered. Naturally, it also spills over to the problem that it is difficult for a user of a device such as a mobile phone or a pocket PC of an information terminal incorporating this liquid crystal display device to view bright images and information.
[0005]
Accordingly, the present invention has been made to improve such a problem, and it is a problem in practical use by reducing the density of the shadow of the adjacent portion of the light guide where the light source is disposed and reducing the size thereof as much as possible. A lighting device that does not reduce the brightness of light emitted from the upper surface of the light guide, a liquid crystal display device that reproduces a clear image using such a lighting device, a mobile phone incorporating this liquid crystal display device, An object is to provide a device such as a pocket PC.
[0006]
[Means for Solving the Problems]
In the illumination device according to claim 1 of the present invention, the incident light adjustment unit provided on one side surface of the light guide is provided for each of the two or more light sources arranged in proximity to the side surface of the light guide. The shape of the opening part of the side part which opposes is a rectangle, the height is shorter than the length of the thickness direction of a light guide, and it is perpendicular to the thickness direction of the light guide, Formed from the same number of recesses as the number of the plurality of light sources provided toward the other side surface, and a bottom surface portion connected to the recesses , the shadow of the emitted light near one side surface of the light guide Can be emitted from the upper surface of the light guide without reducing the brightness on the main light emission surface of the light guide.
[0007]
The illumination device according to claims 2 to 4 of the present invention is such that the shape of the concave portion of the incident light adjusting portion is an arc, a trapezoid or a triangle when viewed from the upper surface or the lower surface of the light guide , and is connected to the concave portion. The bottom face is formed into an arc, trapezoid or triangle having the same shape and the same area, and the same effect as described above can be obtained even if the shape of the recess is changed in this way .
[0008]
In the illumination device according to claim 5 of the present invention, the incident light adjustment unit is provided on the upper surface side of the light guide, and the density of the shadow of the emitted light near one side surface of the light guide is reduced with a small area. It is thin and can prevent the luminance of the main emission surface of the light guide from decreasing.
[0009]
In the illumination device according to claim 6 of the present invention, the incident light adjusting section is provided on the lower surface side of the light guide, and the emitted light from the upper surface of the light guide can be improved.
[0010]
The liquid crystal display device according to a seventh aspect of the present invention can visually recognize a reproduced image by the liquid crystal display element in a good state by using the illumination device according to the first to sixth aspects.
[0011]
By using the liquid crystal display device according to claim 7, the device according to claim 8 of the present invention can provide a device with better visibility of reproduced images and information for the user.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a light guide body of a lighting device of the present invention and a plurality of light sources arranged close to the light guide body, and FIG. 2 is a plan view showing a relative arrangement relationship thereof. The light guides 2, 3 are incident light adjustment units provided in the light guide 1, and the incident light adjustment units 2, 3 have a rectangular shape on the side surface facing the light source, and the thickness of the light guide 1. 4 is a concave portion provided at a height H smaller than L and perpendicular to the thickness direction of the light guide toward the other side surface, and the shape viewed from the upper surface or the lower surface of the light guide plate is an arc shape. 6, and the same arc shape connected to the bottom surface portions 5 and 7 having the same area . Further, the width E of the recesses 4 and 6, it is necessary width D equal to or greater than the size of the light source, the width E and height H of the recess 4, 6, emission light from the upper surface of the light guide 1 You may decide while evaluating.
[0013]
The illumination device according to the present invention is characterized by the shape of the incident light adjusting portions 2 and 3 facing the light sources 8 and 9, and the light guide 1 is not provided with the incident light adjusting portion over the entire thickness of the light guide 1. It is provided partially with respect to the thickness. The lighting device of the present embodiment has the same configuration and arrangement as those of the conventional example shown in FIG. 5, although descriptions of the configuration and arrangement of other light reflectors and light control members are omitted.
[0014]
By configuring the light guide body as described above, light emitted from the light sources 8 and 9 is incident on the side surface of the light guide body 1. Specifically, the light from the light sources 8 and 9 is mainly adjusted for light incidence. Light is incident on the light guide 1 from the side portions of the light guides that are positioned below the portions 2 and 3 and relative to the light source, guided through the inside of the light guide 1, and light is emitted from the upper surface thereof. It will be. Looking at the state of the emitted light from the upper surface of the light guide 1, as shown in FIG. 2, shadows 10, 11, 12 are generated near the side surface of the light guide where the light sources 8, 9 are arranged. ing. However, the shadows 10, 11, and 12 have a very small area and extremely low density, and are reduced to such a level that there is no problem in actual use. In addition, the luminance of the main emission light surface R on the upper surface of the light guide 1 was obtained without decreasing as in the conventional case.
[0015]
FIG. 3 shows another embodiment of the incident light adjusting units 13 and 14 provided in the light guide , and the previous embodiment is a circular arc when viewed from the top surface or the bottom surface of the light guide , and the bottom surface is the same. Whereas the shape is an arc having the same area , the present embodiment has a substantially trapezoidal shape when viewed from the upper surface or the lower surface of the light guide of the incident light adjusting portions 13 and 14, and the bottom surface has the same shape. It has a substantially trapezoidal shape with the same area . FIG. 4 also shows the shape of the light guides of the incident light adjusting sections 15 and 16 as viewed from the upper or lower surface in a triangular shape, and the bottom surface also has the same shape and the same area as a triangular shape . As in both the embodiments, the same effect as in the previous embodiment can be obtained even if the shape of the light guide of the incident light adjusting unit viewed from the upper or lower surface and the shape of the connecting bottom surface are trapezoidal or triangular.
[0016]
In the embodiment described above, the incident light adjustment unit is provided from the upper surface side to the lower surface side of the light guide. However, the same effect can be obtained by providing the incident light adjustment unit from the lower surface side to the upper surface side of the light guide.
[0017]
【The invention's effect】
As described above, the illumination device of the present invention is directed from the upper surface side of the light guide to the lower surface side or from the lower surface side to the upper surface side in the light source facing portion of one side surface of the light guide where the light sources are arranged close to each other. In addition, an incident light adjusting portion that enters toward the other side surface of the light guide is provided, and the shadow in the vicinity of one side surface portion of the light guide plate can be made thin and have a small area. The luminance of the main light emitting surface on the upper surface can be reduced without lowering.
[0018]
In addition, by using this lighting device, it is possible to provide a liquid crystal display device with a clear reproduced image, and to improve the visibility of the reproduced image and information of a device such as a mobile phone or an information terminal incorporating the liquid crystal display device. Can be made.
[Brief description of the drawings]
FIG. 1 is a perspective view of a light guide and a light source in the lighting apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view showing a relative arrangement of the light guide and the light source according to FIG. FIG. 4 is a plan view showing a relative arrangement of a light guide and a light source in a lighting apparatus according to a second embodiment of the present invention. FIG. 4 shows a relative arrangement of a light guide and a light source in the lighting apparatus according to a third embodiment of the present invention. Fig. 5 is a schematic cross-sectional view of a conventional lighting device. Fig. 6 is a perspective view showing the arrangement of a light guide and a light source of the lighting device according to Fig. 5. Fig. 7 is an upper surface of the light guide according to Fig. 6. FIG. 8 is a perspective view showing another form of the conventional light guide. FIG. 9 is a plan view showing the relative arrangement of the light guide and the light source according to FIG. Explanation】
DESCRIPTION OF SYMBOLS 1 Light guide 2, 3 Incident light adjustment part 4, 6 Indentation part 5, 7 Bottom part 8, 9 Light source 13, 14, 15, 16 Incident light adjustment part 18 Light reflecting plate 19 Light control member 20 Circuit board

Claims (8)

Light guide and, two or more of the plurality of light sources which are arranged close to one side surface of the light guide, said plurality of light sources provided at a position respectively opposite to the plurality of light sources to the side surface portion of said one An incident light adjusting unit that causes light emission to be incident on the light guide, a light reflection plate that is disposed on a lower surface side of the light guide and reflects light transmitted through the light guide to the light guide, and the light guide And a light control member that controls an emission direction of light emitted from the upper surface of the light guide, and the incident light adjusting portion is a side portion of the light guide. In addition, the same number as the plurality of light sources in the previous period has openings corresponding to the sizes of the plurality of light sources, has a height shorter than the length in the thickness direction of the light guide , and the depth direction is a recess provided such that the direction toward the other side of the light guide, the bottom was connected to the recess Consisting Part illumination device In the concave portion, the shape of the opening portion of the side surface portion of the previous light guide opposite to each of the plurality of light sources is rectangular, and is perpendicular to the thickness direction of the light guide and on the other side surface side. The shape viewed from above , the shape viewed from the upper surface or the lower surface of the light guide body is an arc shape, and the bottom surface connected to the recess is the same shape and an arc shape of the same area. The lighting device according to 1. In the concave portion, the shape of the opening portion of the side surface portion of the previous light guide opposite to each of the plurality of light sources is rectangular, and is perpendicular to the thickness direction of the light guide and on the other side surface side. A shape provided toward the upper surface of the light guide, or a shape viewed from the lower surface, is a substantially trapezoidal shape having a long side on the side end surface side , and a bottom surface connected to the concave portion has the same shape, The lighting device according to claim 1, wherein the lighting device has a substantially trapezoidal shape with the same area . In the concave portion, the shape of the opening portion of the side surface portion of the light guide body facing the plurality of light sources is rectangular, and is perpendicular to the thickness direction of the light guide body, toward the other side surface side. The shape viewed from the upper surface or the lower surface of the light guide is a substantially triangular shape with the side end surface side as the base, and the bottom surface connected to the recess also has the same shape and the same area. The lighting device according to claim 1, wherein the lighting device has a substantially triangular shape . The illumination device according to claim 1, wherein the incident light adjustment unit is provided on an upper surface side of the light guide. The illumination device according to claim 1, wherein the incident light adjustment unit is provided on a lower surface side of the light guide. The liquid crystal display device which arrange | positions a liquid crystal display element on the upper surface of the light control member of the illuminating device of Claims 1-6. A device incorporating the liquid crystal display device according to claim 7.

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