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Diffusion plate, surface light source device and transmission type display device

A diffuser plate and surface light source technology, which is applied in the field of transmissive display devices, can solve the problems of optical axis deviation, low light utilization efficiency, light intensity spots, etc., achieve correction and convergence of light emission directions, improve diffusion characteristics, and improve The effect of transmittance

Inactive Publication Date: 2005-10-19
DAI NIPPON PRINTING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in such a conventional direct-type surface light source device, there is a problem that the more optical plates are required, the less the converging characteristics of light will be sufficient. In order to make up for this, the structure of the transmissive display unit itself such as LCD panel has been improved. , so that the image quality will not be degraded under the incident light incident from an oblique direction
However, there are problems in this conventional method that not only the utilization efficiency of light is low, but also the structure of a transmissive display such as an LCD panel is complicated, resulting in an increase in cost.
[0005] In addition, there is a problem in the existing direct-type surface light source device that, due to the difference of whether it is close to the cathode tube (that is, the position very close to the cathode tube or the position very close to the gap between the parallel cathode tubes) Can easily cause spots on light intensity (brightness)
[0006] Here, the method for suppressing the above-mentioned light spot can be to increase the distance between the cathode line tube and the transmissive display part such as the LCD panel, but there is a problem that the overall thickness of the display device becomes thicker in this method.
[0007] In addition, the method for suppressing the above-mentioned light spots may be to enhance the degree of diffusion caused by the optical plate arranged between the cathode line tube and the transmissive display part such as the LCD screen, or to limit the amount of light transmission; but in this method There is a problem of reduced light usage
[0008] More specifically, for example, JP-A-5-119703 and JP-A-11-242219 propose a method of maintaining light uniformity in a surface light source device by providing light-shielding parts such as lighting curtains or light-shielding dot layers. , but this method has the same problem as the above method, which has the problem of reducing the amount of light used
[0009] In addition, JP-A-6-347613 proposes a method of controlling diffusion in two directions by using an optical plate provided with cylindrical lenses on both sides in a surface light source device, but this method does not have sufficient light intensity. Convergence function, therefore, there is a problem that different positions in the plane of transmissive display parts such as LCD screens will have optical axis deviations due to different positional relationships with cathode line tubes, and brightness fluctuations will also occur due to different positions of the observed screen. spot

Method used

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  • Diffusion plate, surface light source device and transmission type display device
  • Diffusion plate, surface light source device and transmission type display device
  • Diffusion plate, surface light source device and transmission type display device

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no. 1 Embodiment approach

[0071] first use Figure 1 to Figure 17 The transmissive display device in the first embodiment of the present invention will be described.

[0072] Such as figure 1 As shown, the transmissive display device 10 in the first embodiment of the present invention is a transmissive liquid crystal display device that displays image information by controlling light transmission / non-transmission by using a liquid crystal display element. display part) 11, and a surface light source device 16 that illuminates the LCD screen 11 from the back. Here, the surface light source device 16 at least includes a converging plate 12, a cathode line tube 13, a diffuser plate 14, and a reflective polarizer 15, and uses the surface light source device 16 to irradiate the LCD screen 11 that forms image graphics according to image information from the back side, Thus, an image is displayed on the LCD panel 11 . Additionally, include figure 1 The following figures including the structure are only sc...

no. 2 Embodiment approach

[0157] Second, according to Figure 18 to Figure 21 A transmissive display device in a second embodiment of the present invention will be described. In addition, in the second embodiment of the present invention, the converging plate included in the surface light source device of the transmissive display device is Figure 1 to Figure 17 The shape of the incident-side unit lens 121 of the converging plate 12 shown in the first embodiment is improved, and the converging plate 22 is used as the incident-side unit lens 221. Figure 1 to Figure 17 The first embodiment shown is substantially the same. exist Figure 18 to Figure 21 In the second embodiment shown, for the Figure 1 to Figure 17 In the first embodiment shown, parts having the same functions are denoted by the same symbols, and repeated explanations are appropriately omitted.

[0158] Such as Figure 18 As shown in the cross-section, the converging plate 22 according to the first embodiment of the present invention...

no. 3 Embodiment approach

[0170] Next, according to Figure 22 to Figure 26B A transmissive display device according to a third embodiment of the present invention will be described. In addition, in the third embodiment of the present invention, the diffusion plate included in the surface light source device of the transmissive display device is Figure 1 to Figure 17 The shape of the diffuser lens array 141 of the diffuser plate 14 shown in the first embodiment is modified and the diffuser plate 24 is used as the diffuser lens array 241. Figure 1 to Figure 17 The first embodiment shown is substantially the same. exist Figure 22 to Figure 26B In the third embodiment shown, for the Figure 1 to Figure 17 In the first embodiment shown, parts having the same functions are denoted by the same symbols, and repeated explanations are appropriately omitted.

[0171] Such as Figure 22 As shown, the diffusion plate 24 according to the third embodiment of the present invention is an optical plate for diff...

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Abstract

A diffusing sheet, a surface light source unit, and a transmission type display that can attain uniform illumination so that the brightness of light on the display screen appears uniform regardless of the position from which the display screen is observed. The diffusing sheet includes, on its light-emerging side surface, a diffusion lens array having a plurality of unit lenses, each unit lens being in a shape equivalent to a part of an elliptic cylinder having an elliptical cross section. The surface light source unit includes the diffusing sheet and a convergent sheet 12 that has a plurality of unit lenses 121 having almost trapezoidal cross sections, formed on one surface thereof. It is possible to attain uniform illumination by diffusing light from cathode ray tubes in the surface light source unit, and, at the same time, to converge the light serving as backlight to enhance optical efficiency.

Description

technical field [0001] The present invention relates to a display device such as a liquid crystal display device, particularly a diffusion plate used in a surface light source device for illuminating a transmissive liquid crystal display device from the back, a surface light source device, and a transmissive display using the same device. Background technique [0002] As a surface light source device for illuminating a transmissive liquid crystal display device or the like from the back, various types of surface light source devices have been proposed and put into practical use. Such surface light source devices are mainly classified into edge-lit type and direct-light type according to the method of converting a non-surface light source into a surface light source. [0003] Among them, for example, a direct-type surface light source device utilizes cathode line tubes arranged side by side to directly introduce light from the rear side of a transmi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F21S2/00F21Y103/00G02B3/00G02B3/06G02B3/08G02B5/02G02B27/10G02F1/1335G02F1/13357G09F9/00
CPCG02F2001/133607G02B3/0056G02B19/0047G02B17/0868G02B3/0062G02B3/005G02B3/0031G02B3/04G02B3/08G02B19/0028G02F1/133607B42F7/065B42D15/0006B42D15/008
Inventor 后藤正浩饭田满德原渡
Owner DAI NIPPON PRINTING CO LTD
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