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Illumination device and liquid crystal display device

A technology for lighting devices and liquid crystal panels, which is applied to lighting devices, lighting and heating equipment, light guides of lighting systems, etc., can solve the problems of poor brightness distribution characteristics, taking a long time, and rising product costs.

Inactive Publication Date: 2009-05-06
FUJITSU LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reproducibility of the concave-convex pattern by sandblasting is poor, so it takes a long time to obtain a mold of the desired quality, which causes an increase in product cost
[0015] The light guide plate described in Patent Document 2 has the following problem: Since the cylindrical lens is arranged on the side of the light-emitting surface, the light incident from the light source into the light guide plate It emits to the liquid crystal panel side without sufficiently diffusing into the light guide plate, thus degrading the brightness distribution characteristics

Method used

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  • Illumination device and liquid crystal display device
  • Illumination device and liquid crystal display device
  • Illumination device and liquid crystal display device

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Experimental program
Comparison scheme
Effect test

no. 1 approach

[0057] Figure 6 It is a schematic diagram showing the lighting device of the first embodiment of the present invention and a liquid crystal display device using the lighting device. As that Figure 6 As shown, the liquid crystal display device of this embodiment is composed of a liquid crystal panel 50 and a backlight (illumination device) 60 that is arranged on the back side of the liquid crystal panel 50.

[0058] A liquid crystal 52 is sealed between the two transparent substrates 51a and 51b, thereby forming a liquid crystal panel 50. In addition, on the front side of the liquid crystal panel 50 ( Figure 6 The polarizer 53a is arranged in the middle (upper side), and on the back side ( Figure 6 The middle (lower side) is provided with a polarizer 53b. The size of the liquid crystal panel 50 is, for example, 2 to 4 inches.

[0059] The backlight 60 is composed of a plurality of LEDs 61 serving as a light source, a light guide plate 62, a reflection plate (reflector or white...

no. 2 approach

[0066] Picture 10 It is a diagram showing the shape of a cylindrical lens provided on the light guide plate of the lighting device according to the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that the shape of the cylindrical lens provided on the side of the reflection surface of the light guide plate is different, and the other structure is basically the same as that of the first embodiment, so the description will be omitted and repeated with the first embodiment part.

[0067] Such as Figure 8 As shown, in the light guide plate 62 of the first embodiment, the cylindrical lens 65 and the boundary portion between the cylindrical lenses 65 all have a shape formed as a circle with a radius r. In contrast, in the light guide plate 62 of the second embodiment, as Picture 10 As shown, the cylindrical lens 65 and the boundary portion between each cylindrical lens 65 all have a shape formed according to an ellipse wi...

no. 3 approach

[0072] Picture 12 It is a diagram showing the shape of a cylindrical lens provided on the light guide plate of the lighting device according to the third embodiment of the present invention. The difference between this embodiment and the first embodiment is that the shape of the cylindrical lens provided on the side of the reflection surface of the light guide plate is different, and the other structure is basically the same as that of the first embodiment, so the description will be omitted and repeated with the first embodiment part.

[0073] Such as Picture 12 As shown, in the light guide plate of this embodiment, the cylindrical lens 65 and the boundary portion between the cylindrical lenses 65 are all formed along a sinusoidal curve of h=c(1+sin(x)). In the third embodiment, the boundary portion between the cylindrical lenses 65 is also formed of a concave smooth curved surface, so the same effect as the first embodiment can be obtained.

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Abstract

An illumination device which is better in brightness distribution characteristics than a conventional device and a liquid crystal display device in which the illumination is installed are provided. [MEANS FOR SOLVING THE PROBLEMS] Cylindrical lenses (65) are set on a side of a reflective surface of a light guide plate (62) and concave bent surfaces are connected between these cylindrical lenses. Light output from an LED (61) and traveling into a light guide plate (62) is deflected to various directions at boundary portions of the cylindrical lenses (65). With this structure, a ratio of light reflected in a vertical (thickness) direction at the boundary portions of the cylindrical lens (65) to project to the outside of the light guide plate (62) is reduced, and the occurrence of uneven brightness steaks can be avoided. As a result, display quality of a liquid crystal display device is improved.

Description

Technical field [0001] The present invention relates to a lighting device in which one or more light sources are arranged near the end surface of a light guide plate and a liquid crystal display device using the lighting device. Background technique [0002] Liquid crystal display devices are thin and light, and consume little power, so they are widely used in electronic devices such as mobile phones and portable terminals (PDA: Personal Digital Assistant). The liquid crystal display device used in these electronic devices is usually provided with an illumination device called a backlight. [0003] figure 1 It is a schematic diagram showing an example of a conventional liquid crystal display device (transmissive liquid crystal display device). As that figure 1 As shown, the transmissive liquid crystal display device is composed of a liquid crystal panel 10 and a backlight 20 which is arranged on the back side of the liquid crystal panel 10. [0004] The liquid crystal 12 is se...

Claims

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Application Information

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IPC IPC(8): F21V8/00G02F1/13357G02F1/1335G02B6/00G02B3/06F21Y101/02
CPCG02B6/0046G02B6/0068G02B3/06G02B6/0025G02B6/0038G02B3/005G02B6/0073G02F1/1335G02B6/0001
Inventor 前田智司有竹敬和佐竹贵男藤原晋
Owner FUJITSU LTD