# US 5,227,820 A · Shading device of the LCD projecting plate

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- Number: US 5,227,820 A
- Document ID: US5227820A
- Status: Granted
- Kind: A
- Application number: 07/890,862
- Filed: 1992-06-01
- Granted: 1993-07-13
- Earliest claimed: 1992-06-01
- Assignees: CTX-Electronics Corporation
- Inventors: Kazuhiro Miyashita; Chia-Chen Liao; Chien-Chung Chang
- Web page: https://patentgrep.com/patent/US5227820A

## CPC

- G03B 21/132: Overhead projectors, i.e. capable of projecting hand-writing or drawing during action (epidiascopic projectors G03B21/08)
- Y10S 353/05: Transparency holder accessories
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A shading device of LCD projecting plate has a pair of shading board being capable of being adjusted to shade the rest projecting areas which are uncovered by the plate and to project the drawing or letters on the optical glass to a wall or a screen clearly whenever used with any projectors.

## Claims

### Claim 1

A shading device for an LCD projection plate member located on a projection plane of a projector comprising:
(a) a projection plate member having a pair of guide recesses formed within a bottom section of said projection plate member, said guide recesses extending in a longitudinal direction and being transversely displaced each from the other on opposing transverse ends of said projection plate member;
(b) a pair of shading board members slidably insertable within said guide recesses, each of said shading board members having a pair of longitudinally directed and transversely displaced through openings for insert therethrough of respective threaded members for securement to said bottom section of said projection plate member, whereby said shading board members may be longitudinally displaced to cover said projection plane external to said LCD projection plate member.