TOUCH SYSTEMS AND METHODS EMPLOYING ACOUSTIC SENSING IN A THIN COVER GLASS

• US 20150009185A1
• Filed: 07/02/2014
• Published: 01/08/2015
• Est. Priority Date: 07/08/2013
• Status: Abandoned Application

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Shi, Zhiqiang, Yang, Ningli
• Application Number:
  US14/322,227
• Publication Number:
  US 20150009185A1
• Time in Patent Office: Days
• US Class Current: 345/177
• CPC Class Codes: G06F 3/043 using propagating acoustic waves
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

Touch systems and methods that employ acoustic sensing in a thin glass sheet are disclosed. The touch system includes a generally planar acoustic-sensing assembly that includes the thin glass sheet. Thin-film piezoelectric acoustic transducers are arranged on the top surface or the bottom surface and adjacent the perimeter and serve as either transmitters or receivers. A signal-processing algorithm run on a controller is used to process the receiver signals to determine at least one characteristic of a touch event. Use of a thin glass sheet allows for the acoustic transducers to operate at a frequency f in the range from 0.5 MHz to 5 MHz, thereby providing for excellent pressure sensitivity and spatial resolution of touch events.

Claims

1. A touch system for sensing at least one touch event, comprising:

a glass sheet having a body with a perimeter and generally parallel top and bottom surfaces that define a substantially constant thickness d in the range from 0.1 mm≦

d≦

1 mm;

a plurality of piezoelectric thin-film acoustic transducers formed adjacent the perimeter of the glass sheet on either the top or bottom surface, wherein a first set of the acoustic transducers serve as acoustic-wave transmitters and a second set of the acoustic transducers serve as acoustic-wave receivers that generate receiver signals in response to receiving acoustic waves, wherein the acoustic waves have a frequency f in the range from 0.5 MHz≦

f≦

5 MHz; and

controller means for controlling the activation of the acoustic-wave transmitters and processing the receiver signals to determine at least once characteristic of the at least one touch event.

2. The touch system according to claim 1, wherein the at least one characteristic of the at least one touch event is selected from the group of characteristics comprising:

a touch-event occurrence, a touch-event location, a touch-event duration, a touch-event pressure, and a time-evolution of the touch-event pressure.

3. The touch system according to claim 1, wherein the glass sheet is made of a chemically strengthened glass.

4. The touch system according to claim 1, wherein the acoustic waves comprise pulses having a pulse frequency γ

in the range 1 Hz≦

γ

≦

100 Hz.

5. The touch system according to claim 1, wherein the glass sheet and acoustic transducers are operably disposed relative to a display panel that has touch-sensing capability.

6. The touch system according to claim 5, wherein the display panel includes a transparent acoustic-absorbing film, and wherein the glass sheet locally contacts the acoustic-absorbing film at a location corresponding to the at least one touch event.

7. An acoustic-sensing assembly for a touch system for sensing at least one touch event, comprising:

a glass sheet having a body with a perimeter and generally parallel top and bottom surfaces that define a substantially constant thickness d in the range from 0.1 mm≦

d≦

1 mm;

a plurality of interdigital piezoelectric thin-film acoustic transducers formed adjacent the perimeter of the glass sheet on either the top or bottom surface, wherein a first set of the acoustic transducers serve as acoustic-wave transmitters and a second set of the acoustic transducers serve as acoustic-wave receivers, with each acoustic transducer being adapted to generate acoustic waves having a frequency f in the range from 0.5 MHz≦

f≦

5 MHz when provided with a transmit signal.

8. The acoustic-sensing assembly according to claim 7, wherein the glass sheet is made of a chemically strengthened glass.

9. The acoustic-sensing assembly according to claim 8, wherein the chemically strengthened glass consists of Gorilla®

glass.

10. The acoustic-sensing assembly according to claim 7, wherein the glass sheet has a generally rectangular shape.

11. The acoustic-sensing assembly according to claim 7, wherein the acoustic-wave transmitters and receivers are configured so that the acoustic wave transmitted by a given acoustic-wave transmitter is received by between one and 50 acoustic-wave receivers.

12. A method of sensing at least one touch event, comprising:

sending acoustic waves through a glass sheet having generally parallel top and bottom surfaces that define a substantially constant thickness d in the range 0.1 mm≦

d≦

1 mm, wherein the acoustic waves have a frequency f in the range 0.5 MHz≦

f≦

5 MHz, wherein the acoustic waves are generated by a first set of piezoelectric thin-film acoustic transducers formed on either the top or bottom of the glass sheet;

receiving the acoustic waves with a second set of the acoustic transducers and generating in response receiver signals; and

processing the receiver signals to determine at least once characteristic of the at least one touch event.

13. The method of claim 12, wherein the at least one characteristic of the at least one touch event is selected from the group of characteristics comprising:

a touch-event occurrence, a touch-event location, a touch-event duration, a touch-event pressure, and a time-evolution of the touch-event pressure.

14. The method of claim 12, wherein processing the receiver signals includes performing a baseline measurement when there is no touch event.

15. The method of claim 14, wherein processing the receiver signals includes performing either a line algorithm or a projection algorithm.