Touch panel device

• US 20020097231A1
• Filed: 04/26/2001
• Published: 07/25/2002
• Est. Priority Date: 12/01/2000
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Satoh, Yoshio, Sano, Satoshi, Nakazawa, Fumihiko
• Granted Patent: US 6,762,753 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

A touch panel device includes a plurality of input IDTs for exciting surface acoustic waves and a plurality of output IDTs for receiving the surface acoustic waves, corresponding to a plurality of tracks on a non-piezoelectric substrate, and each input IDT has a wideband electrode structure and each output IDT has a matched filter structure for outputting a large output upon receipt of a specific binary signal sequence. A signal obtained by arranging a plurality of specific signal sequences in time series is applied to each input IDT.

Claims

1. A touch panel device for detecting a position of an object by using a surface acoustic wave, comprising:

a plurality of input IDTs, disposed to correspond to a plurality of tracks of a substrate where the surface acoustic wave can be propagated, respectively, for exciting surface acoustic waves; and

a plurality of output IDTs, disposed to correspond to said plurality of tracks, respectively, for receiving the surface acoustic waves which have been excited by said plurality of input IDTs and propagated along said substrate,

wherein each of said plurality of input IDTs has a wideband electrode structure, and each of said plurality of output IDTs has a matched filter structure for obtaining an output signal upon receipt of a specific signal sequence, the specific signal sequence varying according to each of said plurality of tracks.

2. The touch panel device of claim 1, further comprising:

an application unit for generating the mutually different specific signal sequences in time series and simultaneously applying the generated time-series signal sequences to said plurality of input IDTs, respectively; and

a detection unit for synthesizing output signals of said plurality of output IDTs and detecting a position of a track on which the object exists, based on a result of the synthesis.

3. The touch panel device of claim 2, wherein

during application of the time-series signal sequences to said plurality of input IDTs, respectively, a predetermined time interval is introduced between adjacent signal sequences arranged in time series.

4. The touch panel device of claim 1, wherein

gate signals are generated according to receiving timings of signal sequences matching said plurality of output IDTs, respectively, to selectively fetch an output signal of each of said plurality of output IDTs by masking.

5. The touch panel device of claim 1, wherein

said plurality of input IDTs and/or said plurality of output IDTs are grouped into a plurality of blocks, and the position of the object is detected independently in each block.

6. The touch panel device of claim 5, wherein

a same specific signal sequence is used for different blocks.

7. The touch panel device of claim 1, further comprising at least one set of input/output IDTs for detecting a temperature of said substrate.

8. The touch panel device of claim 7, wherein

an amplifier is connected to said input/output IDTs for temperature detection so as to construct a surface acoustic wave oscillator, and temperature compensation is performed using an oscillation signal of said surface acoustic wave oscillator.

9. The touch panel device of claim 8, wherein

said input/output IDTs for temperature detection have a fundamental period identical with a fundamental period of said input IDT and output IDT for position detection, synthesize said oscillation signal and said specific signal sequences, and apply the resultant synthesized signal to said input IDT for position detection.

10. The touch panel device of claim 1, wherein

said substrate is a transparent non-piezoelectric substrate.

11. The touch panel device of claim 10, wherein

quartz is used as said transparent non-piezoelectric substrate.