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EP0172615A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Liquid crystal panel display apparatus

Assignee: Wacom Co Ltd
•
Filing: 1985-06-10
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Granted: —
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Expires: 2005-06-10
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Abstract

Abstract A liquid crystal panel display apparatus has a generally rectangular tabular light guide plate (10) having a flat upper surface (11), the underside of the light guide plate having at least one tapered surface (15,16) which extends from near one longitudinal end of the light guide plate towards the other end such as to progressively approach the flat upper surface of the light guide plate. The tapered surface is provided with fine convexities and concavities. The apparatus further has a liquid crystal cell device (50) provided on the portion of the upper surface opposing the tapered surface. Light from a light source (30,40) is introduced into the light guide plate and is spread uniformly over the entire area of the portion of the flat upper surface opposing the tapered surface of the light guide plate so as to obtain a uniform illumination over the entire area of the liquid crystal cell device. Only a thin light guide plate and a reflecting mirror need be disposed under the liquid crystal cell device. Consequently, this liquid crystal PAD can be used on a digitizer.

Inventors

  • 👤 Yoji Eto
  • 👤 Hideo Sawa

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-04 20:06
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/046; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/133615

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 89 words
A liquid crystal panel display apparatus comprising: a generally rectangular tabular light guide plate having a flat upper surface, the underside of said light guide plate having at least one tapered surface which extends from a portion of said light guide plate near one longitudinal end surface of said light guide plate towards the other end such as to progressively approach said flat upper surface of said light guide plate; and a transmission-type liquid crystal cell device provided on the portion of said upper surface opposing said tapered surface.
Claim 2
Dependent Claim 89 words
A liquid crystal panel display apparatus comprising: a generally rectangular tabular light guide plate having a flat upper surface, the underside of said light guide plate having at least one tapered surface which extends from a portion of said light guide plate near one longitudinal end surface of said light guide plate towards the other end such as to progressively approach said flat upper surface of said light guide plate; and a transmission-type liquid crystal cell device provided on the portion of said upper surface opposing said tapered surface.
Claim 3
Dependent Claim 43 words
A liquid crystal panel display apparatus according to claim 1, further comprising fine convexities and concavities formed on said tapered surface of said light guide plate, and a reflecting mirror disposed such as to oppose said tapered surface of said light guide plate.
Claim 4
Dependent Claim 32 words
A liquid crystal panel display apparatus according to Claim 1 or Claim 2, comprising a light source means disposed in the vicinity of said one end surface of said light guide plate.
Claim 5
Dependent Claim 25 words
A liquid crystal panel display apparatus according to Claim 2 or Claim 3, wherein a data inputting tablet is disposed under said light guide plate.
Claim 6
Dependent Claim 25 words
A liquid crystal panel display apparatus according to any one of the preceding claims wherein the light guide plate is of an acrylic plastics material.

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