Liquid crystal display apparatus integrated with tablet with non-conductive spacers and smaller conductive substances in compensating layer in tablet

• US 5,831,702 A
• Filed: 11/06/1996
• Issued: 11/03/1998
• Est. Priority Date: 11/15/1995
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Ito, Masaki
• Primary Examiner(s): GROSS, ANITA P
• Application Number:
  US08/744,885
• Time in Patent Office: 727 Days
• Field of Search: 349/12, 345/104, 345/175
• US Class Current: 349/12
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A liquid crystal display apparatus integrated with a tablet for preventing the undesired color development due to double refraction of light passing the STN liquid crystal display cell from occurring also in high-temperature environment. An STN liquid crystal display cell and a tablet are arranged between a pair of polarizing plates. A compensating liquid crystal layer for canceling the wavelength scattering due to double refraction of light passing the liquid crystal display cell is arranged between opposing coordinates detecting electrodes of this tablet. In addition, nonconductive spacer particles and conductive particles are mixed in the compensating liquid crystal layer.

Claims

1. A tablet-integrated liquid crystal display apparatus comprising:

a liquid crystal display cell having a liquid crystal layer oriented in a twisted manner by 180°

or more between a pair of first transparent substrates, said pair of first transparent substrates having inside surfaces with transparent electrodes disposed thereon;

a tablet arranged on a front side of the liquid crystal display cell, said tablet including a pair of second transparent substrates, said pair of second transparent substrates having inside surfaces with coordinate detecting electrodes disposed thereon; and

wherein said liquid crystal display cell comprises a bottom portion of said tablet-integrated liquid crystal display apparatus and said tablet comprises a top portion of said tablet-integrated liquid crystal display apparatus, and further, wherein a pair of polarizing plates are disposed on said bottom and top portions,

wherein a compensating liquid crystal layer for canceling wavelength scattering caused by double refraction of light passing through said liquid crystal display cell is arranged between said pair of second transparent substrates of said tablet, and

wherein non-conductive spacers and conductive substances, lower in height than that of said non-conductive spacers, are disposed in the compensating liquid crystal layer.

2. A tablet-integrated liquid crystal display apparatus as claimed in claim 1, wherein said conductive substances are fixed to one of the transparent substrates of said pair of second transparent substrates of said tablet.

3. A tablet-integrated liquid crystal display apparatus as claimed in claim 1, wherein each said conductive substance is made of a metal-plated plastic bead.

4. A tablet-integrated liquid crystal display apparatus comprising:

a lower transparent substrate;

an intermediate transparent substrate positioned over said lower transparent substrate;

a liquid crystal layer, twisted by at least 180°

, disposed between said lower transparent substrate and said intermediate transparent substrate;

an upper transparent substrate positioned over said intermediate transparent substrate;

a compensating liquid disposed between said upper transparent substrate and said intermediate transparent substrate for canceling wave length scattering caused by a double refraction of light;

a plurality of conductive substances disposed in said compensating liquid;

a plurality of non-conductive spacers disposed in said compensating liquid;

transparent electrodes disposed on an upper surface of said lower transparent substrate and on a lower surface of said intermediate transparent substrate;

coordinate detecting electrodes disposed on an upper surface of said intermediate transparent substrate and on a lower surface of said upper transparent substrate; and

polarizing plates disposed on an upper surface of said upper transparent substrate and on a lower surface of said lower transparent substrate.

5. A tablet-integrated liquid crystal display apparatus of claim 4, wherein each said conductive substance comprises a metal-plated plastic bead.

6. A tablet-integrated liquid crystal display apparatus of claim 4, wherein said conductive substances are fixed to said intermediate transparent layer.

7. A tablet-integrated liquid crystal display apparatus of claim 4, wherein said conductive substances are fixed to said upper transparent layer.