Composite cover material for sensitivity improvement of ultrasonic touch screens

Patent metadata

Field	Value
Publication number	US-11157115-B2
Application number	US-201715476244-A
Country	US
Kind code	B2
Filing date	Mar 31, 2017
Priority date	Mar 31, 2017
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

The present disclosure relates to one or more intermediate layers located on a surface of a cover material of an acoustic touch screen. In some examples, the one or more layers can include one or more intermediate layers. The one or more intermediate layers can include a first layer including a plurality of features and a second layer located between the first layer and the cover material. In a touch condition, the touch object can apply a force to the top surface of the acoustic touch sensor. The applied force can create one or more local bends causing the plurality of features to move closer to the cover material and causing one or more surface discontinuities in the cover material. The acoustic waves can undergo reflections (e.g., causing the signal to be attenuated) due to the discontinuities located in the path of the wave propagation.

First claim

What is claimed is:

1. An acoustic touch sensor comprising:
a cover material;
a transducer coupled to the cover material;
an intermediate material having a first surface configured to receive a force applied by an object contacting the first surface of the intermediate material; and a plurality of predetermined protruding features disposed on a second surface of the intermediate material, opposite the first surface, wherein the plurality of predetermined protruding features includes a plurality of prisms, wherein a first set of the plurality of predetermined protruding features located at a first region of the second surface of the intermediate material has a first density, and wherein a second set of the plurality of predetermined protruding features located at a second region of the second surface of the intermediate material has a second density, different than the first density;
a gap between the plurality of predetermined protruding features disposed on the second surface of the intermediate material and the cover material; and
sensing circuitry configured to determine whether the object is contacting the first surface of the intermediate material based on acoustic energy transmitted by the transducer into the cover material and a contact between the protruding features on the second surface of the intermediate material and the cover material,
wherein determining whether the object is contacting the first surface of the intermediate material comprises:
determining that a first protruding feature of the plurality of predetermined protruding features at a first location is contacting the cover material; and
determining that a second protruding feature of the plurality of predetermined protruding features at a second location, different from the first location, is not contacting the cover material.

2. The acoustic touch sensor of claim 1 , wherein the touch sensor further comprises:
a second layer located between the intermediate material and the cover material.

3. The acoustic touch sensor of claim 2 , wherein the intermediate layer includes one or more bends such that some of the plurality of predetermined protruding features touch the cover material, wherein the one or more bends create one or more surface discontinuities on the cover material.

4. The acoustic touch sensor of claim 2 , wherein:
at least some of the plurality of predetermined protruding features of the intermediate layer are configured to transfer the force applied by the object to the cover material, and
at least others of the plurality of predetermined protruding features of the intermediate layer are configured to maintain structural properties when the force is applied by the touch object.

5. The acoustic touch sensor of claim 4 , the surface of the device including one or more regions capable of being contacted by the object,
at least some of the plurality of predetermined protruding features are located at the one or more regions, and
at least others of the plurality of predetermined protruding features are located outside of the one or more regions.

6. The acoustic touch sensor of claim 2 , wherein the intermediate layer includes one or more other regions that exclude features.

7. The acoustic touch sensor of claim 6 , wherein the one or more other regions are located at a border region of the device.

8. The acoustic touch sensor of claim 2 , wherein the second layer includes one or more of air and a gel.

9. The acoustic touch sensor of claim 1 , wherein the intermediate layer includes one or more of glass, onyx, and sapphire.

10. The acoustic touch sensor of claim 1 , wherein the plurality of predetermined protruding features is non-uniformly distributed throughout the first layer.

11. The acoustic touch sensor of claim 1 , wherein a size of each of the plurality of predetermined protruding features is between 5-10 microns.

12. The acoustic touch sensor of claim 1 , wherein a thickness of the intermediate layer is between 50-60 microns.

13. The acoustic touch sensor of claim 1 , further comprising:
transmit circuitry configured to provide a stimulation signal to the transducer; and
receive circuitry configured to capture a received signal based on motion of the transducer,
wherein the control circuitry is further configured to:
couple the transmit circuitry to the transducer,
couple the receive circuitry to the transducer,
stimulate the transducer to produce an excitation in the cover material,
capture a reflected energy between the transducer and one or more surface discontinuities on the cover material, and
determine a location of the object contacting the surface of the device based on the reflected energy.

14. The acoustic touch sensor of claim 1 , wherein each of the plurality of predetermined protruding features narrows at a constant slope.

15. The acoustic touch sensor of claim 1 , wherein a spacing between the plurality of predetermined protruding features is based on a characteristic of the acoustic energy transmitted by the transducer.

16. The acoustic touch sensor of claim 1 , wherein a pattern of the plurality of predetermined protruding features is known at manufacture time.

17. A method for detecting an object contacting a first surface of an intermediate layer of a device having the first surface configured to receive a force applied by the object contacting the first surface of the first surface and a second surface, opposite the first surface, having a plurality of predetermined protruding features disposed thereon, wherein the plurality of predetermined protruding features includes a plurality of prisms, wherein a first set of the plurality of predetermined protruding features located at a first region of the second surface of the intermediate material has a first density, and wherein a second set of the plurality of predetermined protruding features located at a second region of the second surface of the intermediate material has a second density, different than the first density, the method comprising:
transmitting an acoustic wave into a surface of a cover material, different from the intermediate layer, wherein the acoustic wave is transmitted from a transducer, wherein a gap is present between the plurality of protruding features the cover material;
receiving an acoustic reflection of the acoustic wave transmitted into the surface of the cover material; and
determining whether the object is contacting a first surface of the intermediate layer, wherein determining whether the object is contacting the first surface of the intermediate material comprises:
determining that a first protruding feature of the plurality of predetermined protruding features at a first location is contacting the cover material; and
determining that a second protruding feature of the plurality of predetermined protruding features at a second location, different from the first location, is not contacting the cover material.

18. The method of claim 17 , wherein creating the one or more surface discontinuities includes decreasing a gap between the protruding features and the cover material such that the protruding features contacts the cover material.

19. The method of claim 17 , wherein the one or more bends and one or more surface discontinuities are located in one or more regions of the device, the method further comprising:
maintaining a space between the protruding features included on the second opposing surface of the intermediate material and the cover glass outside of the one or more regions.

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Assignees

• Apple Inc

Inventors

• Khajeh Ehsan
• King Brian Michael
• Yip Marcus
• Tucker Aaron Scott
• YEKE YAZDANDOOST Mohammad
• Yousefpor Marduke
• Gozzini Giovanni

Classifications

• G06F3/0393

  Accessories for touch pads or touch screens, e.g. mechanical guides added to touch screens for drawing straight lines, hard keys overlaying touch screens or touch pads · CPC title

• G06F2203/04103

  Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices · CPC title

• G06F3/04166

  Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving (Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184) · CPC title

• G06F3/0436 Primary

  in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate · CPC title

• G06F3/04142

  the force sensing means being located peripherally, e.g. disposed at the corners or at the side of a touch sensing plate · CPC title