Surface light source capable of changing range of spread angle of exit light, and liquid crystal display apparatus using this surface light source

Inactive Publication Date: 2007-06-21
CASIO COMPUTER CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012] It is an object of the present invention to provide a surface light source that can change a range of a spread angle of exit light.
[0013] It is another object of the present invention to provide a liquid crystal display apparatus that can vary a viewing angle by using a surface light source that can change a range of a spread angle of exit light.
[0016] an optical deflection element that changes light emitted from the first light source into first illumination light having a maximum value of an exit light intensity present in a direction parallel to a normal line of the surface light source, a predetermined spread angle range, and high directivity in a direction of the normal line and allows the changed light to exit therefrom; and that changes light emitted from the second light source into second illumination light having a maximum value of an exit light intensity in an oblique direction inclined at a predetermined angle with respect to the normal line of the surface light source and a spread angle range wider than that of the first illumination light and allows the changed light to exit therefrom.

Problems solved by technology

Therefore, the display image of the liquid crystal display device cannot be recognized from the one direction and the direction inclined to the opposite side, the viewing angle of the display image is apparently restricted, and the viewing angle of the display image is narrowed.
However, according the viewing angle restricting liquid crystal element in which liquid crystal molecules are aligned in different alignment states in accordance with each sectional region obtained by dividing a region corresponding to a screen of the liquid crystal display device, complicated alignment processing (rubbing processing of an alignment film) whose direction varies in accordance with each sectional region must be applied to each of the inner surfaces of the pair of substrates, and hence manufacture is difficult.

Method used

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  • Surface light source capable of changing range of spread angle of exit light, and liquid crystal display apparatus using this surface light source
  • Surface light source capable of changing range of spread angle of exit light, and liquid crystal display apparatus using this surface light source
  • Surface light source capable of changing range of spread angle of exit light, and liquid crystal display apparatus using this surface light source

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Experimental program
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first embodiment

[0048] FIGS. 1 to 8B show a first embodiment according to the present invention, wherein FIG. 1 is an exploded perspective view of a liquid crystal display apparatus.

[0049] As shown in FIG. 1, this liquid crystal display apparatus includes: a liquid crystal display device 1, a surface light source 9, and a controller 27. The display device includes a screen region 1a in which a plurality of pixels that control transmission of light are aligned in a matrix form, and displays an image corresponding to an image signal supplied to each of the plurality of pixels. The surface light source 9 is arranged on an opposite side of an observation side (a left side in FIG. 1) of this liquid crystal display device 1. The controller 27 is electrically connected to the liquid crystal display panel 1 and the surface light source 9 to control them. The surface light source 9 emits first and second illumination lights toward the liquid crystal display device 1.

[0050] The first illumination light has...

second embodiment

[0102] FIGS. 9 to 13C show a second embodiment according to the present invention. FIG. 9 is a block circuit diagram of a controller 27 that drives a liquid crystal display device 1 and a surface light source 9.

[0103] In a liquid crystal display apparatus according to this embodiment, the controller 27 includes a fixed image data generating section 28, first and second image data memories 29 and 30, a memory write control section 31, a memory read control section 32, a light source drive section 33, and a drive control section 34. The fixed image data generating section 28 generates fixed image data corresponding to a pre-registered fixed image. The memory write control section 31 writes display image data corresponding to image data supplied from the outside into the first memory 29, and selectively writes the display image data and the fixed image data into the second memory 30 in accordance with a viewing angle selection signal. The memory read control section 32 alternately rea...

third embodiment

[0124]FIGS. 14 and 15 show a surface light source 90 according to a third embodiment of the present invention. FIG. 14 is a front view of the surface light source 90 arranged to face a rear surface of the liquid crystal display device on an opposite side of an observation side as seen from an exit side. FIG. 15 is a cross-sectional view taken along a line XV-XV in FIG. 14. It is to be noted that like reference numerals denote the same members as those in the first embodiment, thereby omitting an explanation thereof.

[0125] The surface light source 90 according to this embodiment is arranged to face a surface of a liquid crystal display device 1 on an opposite side of an observation side like the liquid crystal display apparatus depicted in FIG. 1. This surface light source 90 has a light guide plate 91 formed of a tabular transparent member, e.g., an acrylic resin plate, a prism sheet 92 that allows light from this light guide plate 91 to exit toward the liquid crystal display devic...

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Abstract

A surface light source includes first and second light sources that emit lights, and an optical deflection element. The optical deflection element changes light emitted from the first light source into first illumination light having a maximum value of an exit light intensity present in a direction parallel to a normal line of the surface light source, a spread angle range, and high directivity in a direction of the normal line and allows the changed light to exit therefrom. The optical deflection element also changes light emitted from the second light source into second illumination light having a maximum value of an exit light intensity in an oblique direction inclined at an angle with respect to the normal line and a spread angle range wider than that of the first illumination light and allows the changed light to exit therefrom.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-368290, filed Dec. 21, 2005, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a surface light source capable of changing a range of a spread angle of exit light, and a liquid crystal display apparatus that can vary a viewing angle by using this surface light source. [0004] 2. Description of the Related Art [0005] A liquid crystal display apparatus has a structure in which a surface light source that emits light having a substantially uniform intensity to a substantially entire surface of a liquid crystal display device is arranged on an opposite side of an observation side of the liquid crystal display device having a screen region in which a plurality of pixels that control transmission of light are aligned...

Claims

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Application Information

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IPC IPC(8): F21V7/04
CPCG02B6/0038G02B6/0053G02F1/1335G02B6/0001G02B6/00
InventorDAIKU, YASUHIRO
OwnerCASIO COMPUTER CO LTD