Integrated resistor for measuring touch position in a liquid crystal display device

• US 6,204,897 B1
• Filed: 08/18/1998
• Issued: 03/20/2001
• Est. Priority Date: 08/18/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Colgan, Evan George, Schappert, Michael Alan, Levine, James Lewis
• Primary Examiner(s): Parker, Kenneth
• Application Number:
  US09/135,586
• Time in Patent Office: 945 Days
• Field of Search: 345/174, 345/104, 178/18.05, 349/12
• US Class Current: 349/12
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 2203/04113 Peripheral electrode pattern in resistive digitisers, i.e. electrodes at the periphery of the resistive sheet are shaped in patterns enhancing linearity of induced field
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners

Abstract

The present invention provides for a liquid crystal display device with a signal layer integrated onto a substrate. Circuitry derives touch position based upon response to signals applied to the signal layer. At least one resistor is integrated onto the substrate. The resistor is coupled between the signal layer and the circuitry. The resistor is formed in conjunction with the signal layer. Preferably, the resistor is part of a resistor network for linearizing resistance of the signal layer in a vertical direction and horizontal direction.

Claims

1. A liquid crystal display device comprising;

a substrate;

a signal layer integrally disposed on said substrate, wherein touch position is derived by circuitry according to response to signals applied to said signal layer, wherein said signal layer is formed from a substantially transparent conductive material;

a patterned layer integrally diagnosed on said substrate wherein said patterned layer comprises a light absorbing material that has low reflectivity and blocks transmission of light; and

at least one resistor integrally disposed on said substrate, coupled between said signal layer and said circuitry, wherein said at least one resistor comprises a first layer formed from said substantially transparent conductive material of said signal layer and a second layer formed from said light absorbing material of said patterned layer.

2. The liquid crystal display of claim 1, wherein said light absorbing material comprises one of chromium and chromium oxide.

3. The liquid crystal display device of claim 2, wherein said substantially transparent conductive material comprises indium tin oxide.

4. The liquid crystal display device of claim 1, wherein said at least one resistor is part of a resistor network for linearizing resistance of said signal layer in a vertical direction and horizontal direction.

5. The liquid crystal display device of claim 4, wherein said resistor network comprises a plurality of resistive strips and a plurality of serpentine resistors coupled between said resistive strips and said signal layer.

6. A method for manufacturing a liquid crystal display device comprising the steps of;

forming a signal layer integrally disposed on a substrate, wherein touch position is derived by circuitry according to response to signals applied to said signal layer, wherein said signal layer is formed from a substantially transparent conductive material;

forming a patterned layer integrally disposed on said substrate, wherein said patterned layer comprises a light absorbing material that has low reflectivity and blocks transmission of light; and

forming at least one resistor integrally disposed on said substrate, wherein said at least one resistor comprises a first layer formed from said substantially transparent conductive material of said signal layer and a second layer formed from said light absorbing material of said patterned layer.

7. The method of claim 6, wherein said light absorbing material comprises one of chromium and chromium oxide.

8. The method of claim 7, wherein said substantially transparent conductive material comprises indium tin oxide.

9. The method of claim 6, wherein said at least one resistor is part of a resistor network for linearizing resistance of said signal layer in a vertical direction and horizontal direction.

10. The method of claim 9, wherein said resistor network comprises a plurality of resistive strips and a plurality of serpentine resistors coupled between said resistive strips and said signal layer.