Coordinate detecting device

• US 8,576,194 B2
• Filed: 04/13/2009
• Issued: 11/05/2013
• Est. Priority Date: 05/15/2008
• Status: Active Grant

• Current Assignee: Fujitsu Component Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Component Limited (Fujitsu Limited)
• Inventors: Kondoh, Koichi
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): REGN, MARK W
• Application Number:
  US12/422,323
• Publication Number:
  US 20090283339A1
• Time in Patent Office: 1,667 Days
• Field of Search: 345/174, 178/18.05
• US Class Current: 345/174
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A coordinate detecting device includes a resistive film formed over a substrate; and a common electrode formed over the resistive film for applying a voltage to the resistive film. The coordinate detecting device generates potential distribution in the resistive film by applying the voltage to the resistive film from the common electrode and detects a coordinate of a contact position of the resistive film by detecting a potential of the contact position of the resistive film. The substrate is formed of an insulator in a square shape. The common electrode is formed along an edge part of the substrate. The resistive film under the common electrode has one or more areas where the resistive film does not exist. An L-shaped resistive film absent area where the resistive film does not exist is provided in one or more corners of the substrate and on the same side of the common electrode as a side where a center of the substrate is situated.

Claims

1. A coordinate detecting device comprising:

a substrate formed of an insulator;

a resistive film formed over the substrate; and

a common electrode formed along four sides of the substrate over the resistive film for applying a voltage to the resistive film,

wherein the resistive film includes resistive film absent areas where the resistive film does not exist, said resistive film absent areas being arranged along the four sides of the substrate, and L-shaped resistive film absent areas formed apart from each other at each corner of the substrate,

the L-shaped resistive film absent areas are provided on the substrate more inwardly than any of the resistive film absent areas and the common electrode; and

the resistive film absent areas located along any one of the four sides are arranged so as to have pitches which become narrower toward a center part of the any one of the four side of the substrate.

2. The coordinate detecting device as claimed in claim 1, wherein an insulating film having a contact hole at a position corresponding to a predetermined area of the common electrode is formed on the common electrode;

and a conductive material is provided in the contact hole, to form a driving voltage applying unit for applying a voltage to the resistive film through the common electrode.

3. The coordinate detecting device as claimed in claim 1, wherein the resistive film is formed of a material that is transparent in a visible region of spectrum;

and the L-shaped resistive film absent area is formed by irradiating the resistive film with a laser light having a light emission wavelength of an infrared region or an ultraviolet region.

4. The coordinate detecting device as claimed in claim 1, further comprising a wire stacked over the common electrode with an interlayer insulating film interposed therebetween.

5. The coordinate detecting device as claimed in claim 1, further comprising a resistive type coordinate positioning unit for detecting a coordinate position.

6. The coordinate detecting device as claimed in claim 1, further comprising an electrostatic capacitor type coordinate positioning unit for detecting a coordinate position.

7. The coordinate detecting device as claimed in claim 1, wherein each of the resistive film absent areas is formed so that only outer periphery portion of the resistive film of each of the resistive film absent areas is removed while the resistive film surrounded by the outer periphery portion remains.

8. A coordinate detecting device comprising:

a substrate formed of an insulator;

a resistive film formed over the substrate; and

a common electrode formed along four sides of the substrate for applying a voltage to the resistive film,

wherein the resistive film includes a first resistive film absent area where the resistive film does not exist, said first resistive film absent area being arranged along the four sides of the substrate;

a space between adjacent sides of the common electrode and the first resistive film absent area is 0 mm to 5 mm; and

the resistive film further includes an L-shaped second resistive film absent areas formed apart from each other at each corner of the substrate;

the L-shaped resistive film absent area is provided on the substrate more inwardly than any one of the first resistive film absent area and the common electrode; and

the first resistive film absent areas located along any one of the four sides are arranged so as to have pitches which become narrower toward a center part of the any one of the four side of the substrate.

9. A coordinate detecting device comprising:

a substrate formed of an insulator;

a resistive film formed over the substrate; and

a plurality of common electrodes, each of the plurality of common electrodes being formed along one of four sides of the substrate over the resistive film for applying a voltage to the resistive film,

wherein the resistive film includes resistive film absent areas where the resistive film does not exist, said resistive film absent areas being arranged along the four sides of the substrate, and L-shaped resistive film absent areas formed at each corner of the substrate, and

the L-shaped resistive film absent areas are provided on the substrate more inwardly than any of the resistive film absent areas and the common electrode.

10. The coordinate detecting device according to claim 9, wherein each of the resistive film absent areas is formed along sides of a rectangular area, and resistive film outside the resistive film absent area and resistive film remaining inside the resistive film absent area are electrically insulated from each other.

11. The coordinate detecting device according to claim 9, wherein

the resistive film absent areas are formed within an area surrounded by the common electrodes.