US 5,671,028 AGranted

Liquid crystal display including a control member for providing a transparent visual range within a predetermined viewing angle and an opaque visual range outside the predetermined viewing angle

AssigneeSharp Kabushiki Kaisha

InventorMasanobu Okano

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Abstract

In an lighting device, light rays, which have been illuminated from a discharge tube onto a light-guiding body and have been released from a light-emitting surface of the light-guiding body, are converged toward the normal direction by prisms each of which has a triangle- column shape and is installed on a light-converging control plate. A visual-range control plate provides a transparent visual range with a predetermined viewing angle with respect to the normal direction, while providing an opaque visual range outside the predetermined viewing angle with respect to the normal direction. This arrangement makes it possible to improve the surface luminance of the lighting device and prevent the degradation of the display quality. Thus, it is possible to achieve high-luminance, high quality lighting devices.

Claims13

Dependent claims

A liquid crystal display comprising:

a liquid crystal display panel;
a light-guiding plate on the back side of and in parallel with the liquid crystal display panel;
a light source for allowing light rays to be incident on at least one edge face of the light-guiding plate;
a light-converging plate for transmitting light rays released from the light-guiding plate while converging the light rays in the normal direction, the light-converging plate being positioned between the light-guiding plate and the liquid crystal display panel;
and
a visual range control member for providing a transparent visual range with a predetermined viewing angle with respect to the normal direction as well as for providing an opaque visual range outside the predetermined viewing angle with respect to the normal direction, the visual-range control member being positioned between the light-converging plate and the liquid crystal display panel.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/435,137Filed 5 May 1995
Priority: JP 6-09741111 May 1994
Granted: 23 Sep 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G02B 6/0053
Provided by one optical element, or plurality thereof, placed on the light output side of the light guide: prismatic sheet or layer; Brightness…
G02F 1/133524
Structural association of cells with optical devices, e.g. polarisers or reflectors: light-guides, e.g. fibre-optic bundles, louvered or jalousie…
G02B 6/0043
Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles: provided on the surface of the light guide
G02F 1/133567
Characterised by the placement of the optical elements: on the back side