COORDINATE DETECTING DEVICE

• US 20090283339A1
• Filed: 04/13/2009
• Published: 11/19/2009
• 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
• Granted Patent: US 8,576,194 B2
• Time in Patent Office: Days
• US Class Current: 178/18.50
• 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 resistive film formed over a substrate; and

a common electrode formed over the resistive film for applying a voltage to the resistive film,

said coordinate detecting device being configured to generate potential distribution in the resistive film by applying the voltage to the resistive film from the common electrode and configured to detect a coordinate of a contact position of the resistive film by detecting a potential of the contact position of the resistive film,

wherein 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 resistive film absent areas where the resistive film does not exist; and

an L-shaped resistive film absent area where the resistive film does not exist is provided in one or more corners of the square shape of the substrate and on the same side of the common electrode as a side where a center of the substrate is situated.

3. 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.

4. 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 second 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.

5. The coordinate detecting device as claimed in claim 1, wherein the first resistive film absent area has an edge part where the resistive film is removed and an inner part where the resistive film remains on an inner side of the edge part;

and the inner part is electrically insulated from the resistive film and provided outside the edge part.

6. 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.

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

2. A coordinate detecting device comprising:

a resistive film formed over a substrate; and

a common electrode formed over the resistive film for applying a voltage to the resistive film,

said coordinate detecting device being configured to generate potential distribution in the resistive film by applying the voltage to the resistive film from the common electrode and configured to detect a coordinate of a contact position of the resistive film by detecting a potential of the contact position of the resistive film,

wherein the substrate is formed of an insulator in a square shape;

a first resistive film absent area where the resistive film does not exist is provided adjacent to the common electrode and on the same side of the common electrode as a side where a center of the substrate is situated;

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

an L-shaped second resistive film absent area is provided in one or more corners of the square shape of the substrate and on the same side of the common electrode as the side where the center of the substrate is situated.