Touch panel device

• US 20030234773A1
• Filed: 01/29/2003
• Published: 12/25/2003
• Est. Priority Date: 06/24/2002
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Takahashi, Yuji, Katsuki, Takashi, Sano, Satoshi, Nakazawa, Fumihiko
• Granted Patent: US 7,230,612 B2
• Time in Patent Office: Days
• 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

Surface acoustic waves are propagated in a lower-left oblique direction and a lower-right oblique direction from an excitation element located on the upper side of a non-piezoelectric substrate and then received by receiving elements located on the left side and the right side, while surface acoustic waves are propagated in an upper-left oblique direction and an upper-right oblique direction from an excitation element located on the lower side of the non-piezoelectric substrate and then received by the receiving elements located on the left side and the right side. Based on the received results at the two receiving elements, a position of an object in contact with the non-piezoelectric substrate is detected. The sensitivity in a region near the diagonal, which is influenced largely by propagation loss of the surface acoustic waves, is improved by increasing the widths of the electrode fingers of the excitation elements and/or the receiving elements, the number of pairs of the electrode fingers, or the aperture width of comb-like electrodes, according to an increase in the propagation distances of the surface acoustic waves, i.e., toward the region near the diagonal.

Claims

1. A touch panel device comprising:

a rectangular substrate; and

excitation elements for exciting surface acoustic waves and receiving elements for receiving surface acoustic waves, said excitation elements and said receiving elements being disposed at peripheral sections in diagonal directions of said substrate to form pairs,

wherein surface acoustic waves are propagated between said excitation elements and said receiving elements in diagonal directions on said substrate, and a position of an object in contact with said substrate is detected based on received results at said receiving elements, and

wherein said excitation elements and said receiving elements have comb-like electrode fingers, and widths of said comb-like electrode fingers of said excitation elements and/or said receiving elements are set according to lengths of propagation distances of the surface acoustic waves.

2. The touch panel device of claim 1,

wherein each of said excitation elements and said receiving elements comprises a film-like piezoelectric body, a comb-like electrode formed on one surface of said piezoelectric body, and a plate electrode formed on the other surface of said piezoelectric body.

3. A touch panel device comprising:

a rectangular substrate; and

excitation elements for exciting surface acoustic waves and receiving elements for receiving surface acoustic waves, said excitation elements and said receiving elements being disposed at peripheral sections in diagonal directions of said substrate to form pairs,

wherein surface acoustic waves are propagated between said excitation elements and said receiving elements in diagonal directions on said substrate, and a position of an object in contact with said substrate is detected based on received results at said receiving elements, and

wherein said excitation elements and said receiving elements have comb-like electrode fingers, and the number of pairs of said comb-like electrode fingers of said excitation elements and/or said receiving elements is set according to lengths of propagation distances of the surface acoustic waves.

4. The touch panel device of claim 3,

wherein each of said excitation elements and said receiving elements comprises a film-like piezoelectric body, a comb-like electrode formed on one surface of said piezoelectric body, and a plate electrode formed on the other surface of said piezoelectric body.

5. A touch panel device comprising:

a rectangular substrate; and

excitation elements for exciting surface acoustic waves and receiving elements for receiving surface acoustic waves, said excitation elements and said receiving elements being disposed at peripheral sections in diagonal directions of said substrate to form pairs,

wherein surface acoustic waves are propagated between said excitation elements and said receiving elements in diagonal directions on said substrate, and a position of an object in contact with said substrate is detected based on received results at said receiving elements, and

wherein each of said excitation elements and said receiving elements comprises a comb-like electrode having a plurality of electrode fingers, and an aperture width of said comb-like electrode of said excitation elements and/or said receiving elements is set according to lengths of propagation distances of the surface acoustic waves.

6. The touch panel device of claim 5,

wherein each of said excitation elements and said receiving elements comprises a film-like piezoelectric body, a comb-like electrode formed on one surface of said piezoelectric body, and a plate electrode formed on the other surface of said piezoelectric body.

7. A touch panel device comprising:

a rectangular substrate; and

excitation elements for exciting surface acoustic waves and receiving elements for receiving surface acoustic waves, said excitation elements and said receiving elements being disposed at peripheral sections in diagonal directions of said substrate to form pairs,

wherein surface acoustic waves are propagated between said excitation elements and said receiving elements in diagonal directions on said substrate, and a position of an object in contact with said substrate is detected based on received results at said receiving elements, and

wherein each of said excitation elements and said receiving elements has a plurality of terminals at different positions for connection to an external device, and the terminal on a side where a propagation distance of the surface acoustic waves is longer is selectively used.

8. The touch panel device of claim 7,

wherein each of said excitation elements and said receiving elements comprises a film-like piezoelectric body, a comb-like electrode formed on one surface of said piezoelectric body, and a plate electrode formed on the other surface of said piezoelectric body.

9. A touch panel device comprising:

a rectangular substrate; and

excitation elements for exciting surface acoustic waves and receiving elements for receiving surface acoustic waves, said excitation elements and said receiving elements being disposed at peripheral sections in diagonal directions of said substrate to form pairs,

wherein surface acoustic waves are propagated between said excitation elements and said receiving elements in diagonal directions on said substrate, and a position of an object in contact with said substrate is detected based on received results at said receiving elements, and

wherein said touch panel device further comprises additional excitation elements for exciting surface acoustic waves and additional receiving elements for receiving surface acoustic waves, disposed at four corners of said substrate to form pairs.

10. The touch panel device of claim 9,

wherein each of said excitation elements and said receiving elements comprises a film-like piezoelectric body, a comb-like electrode formed on one surface of said piezoelectric body, and a plate electrode formed on the other surface of said piezoelectric body.