Touch panel device

• US 6,911,973 B2
• Filed: 11/05/2001
• Issued: 06/28/2005
• Est. Priority Date: 07/16/2001
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Takahashi, Yuji, Katsuki, Takashi, Sano, Satoshi, Nakazawa, Fumihiko
• Primary Examiner(s): Chow, Dennis-Doon
• Assistant Examiner(s): Jorgensen, Leland R.
• Application Number:
  US09/985,527
• Publication Number:
  US 20030011577A1
• Time in Patent Office: 1,331 Days
• Field of Search: 345173-178, 178 1804- 1811, 178 1901- 1907, 178 2001- 2004, 310/313.A, 310/313.R, 310/313.B, 310/313.C, 310/313.D
• US Class Current: 345/177
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

A touch panel device is provided that can detect a touched position with sufficient resolution and accuracy without requiring high accuracy in process for forming a piezoelectric thin film. In the middle portion of the glass substrate, a substantially rectangular touch area is provided. In the periphery of the touch area, plural transmission comb electrodes arranged along one of the neighboring sides of the touch area and plural reception comb electrodes arranged along the other of the neighboring sides make pairs. Surface acoustic wave signals propagate from the transmission comb electrodes to the reception comb electrodes in a slanting direction with respect to four sides of the touch area. The inside edge of the piezoelectric thin film is formed linearly along the sides of the touch area. Each of the comb electrodes 13 and 14 are arranged so that the line along the electrode finger of the transmission comb electrode and the line along the electrode finger of the reception comb electrode are non-parallel with each other in accordance with an angle of refraction of the surface acoustic wave at the boundary between the piezoelectric thin film and the touch area.

Claims

1. A touch panel device comprising:

a non-piezoelectric substrate;

a substantially rectangular touch area located in the middle portion of the non-piezoelectric substrate;

a piezoelectric thin film located around the touch area;

plural pairs of transmission comb electrodes and reception comb electrodes of surface acoustic wave elements around the touch area, the plural transmission comb electrodes located along one of the neighboring sides of the touch area and the plural reception comb electrodes located along the other of the neighboring sides of the touch area constituting plural pairs, so that surface acoustic wave signals propagate from the transmission comb electrodes to the reception comb electrodes in a slanting direction with respect to four sides of the touch area;

the piezoelectric thin film having a linear inside edge along the four sides of the touch area; and

a line along an electrode finger of the transmission comb electrode and a line along an electrode finger of the reception comb electrode being non-parallel with each other in accordance with an angle of refraction of the surface acoustic wave at a boundary between the piezoelectric thin film and the touch area.

2. The touch panel device according to claim 1, wherein the piezoelectric thin film is made of zinc oxide, and each of the comb electrodes is arranged so that the line along the electrode finger of the transmission comb electrode and the line along the electrode finger of the reception comb electrode are non-parallel with each other so as to open at the touch area side.

3. The touch panel device according to claim 1, wherein the piezoelectric thin film is made of aluminum nitride, and each of the comb electrodes is arranged so that the line along the electrode finger of the transmission comb electrode and the line along the electrode finger of the reception comb electrode are non-parallel with each other so as to intersect at the touch area side.

4. A touch panel device comprising:

a non-piezoelectric substrate;

a substantially rectangular touch area located in the middle portion of the non-piezoelectric substrate;

surface acoustic wave transmission elements and reception elements located around the touch area, each of the elements including a continuous comb electrode having a pair of parallel electrodes and comb electrode fingers extending from one of the parallel electrodes toward the other in a slanting direction at a constant pitch alternately and a piezoelectric thin film;

the continuous comb electrode of the transmission element located along one of the neighboring sides of the touch area and the continuous comb electrode of the reception element located along the other of the neighboring sides of the touch area constituting a pair, so that surface acoustic wave signals propagate from the continuous comb electrode of the transmission element to the continuous comb electrode of the reception element in a slanting direction with respect to four sides of the touch area;

the piezoelectric thin film having a linear inside edge along the four sides of the touch area; and

a line along a comb electrode finger of the transmission element and a line along a comb electrode finger of the reception element being non-parallel with each other in accordance with an angle of refraction of the surface acoustic wave at a boundary between the piezoelectric thin film and the touch area.

5. The touch panel device according to claim 4, wherein the piezoelectric thin film is made of zinc oxide, and each of the continuous comb electrodes is formed so that the line along the comb electrode finger of the transmission element and the line along the comb electrode finger of the reception element are non-parallel with each other so as to open at the touch area side.

6. The touch panel device according to claim 4, wherein the piezoelectric thin film is made of aluminum nitride, and each of the continuous comb electrodes is formed so that the line along the comb electrode finger of the transmission element and the line along the comb electrode finger of the reception element are non-parallel with each other so as to intersect at the touch area side.