Pressure Sensing Display Device

• US 20170359064A1
• Filed: 08/06/2017
• Published: 12/14/2017
• Est. Priority Date: 07/05/2012
• Status: Abandoned Application

• Current Assignee: Cambridge Touch Technologies, Ltd.
• Original Assignee: Cambridge Touch Technologies, Ltd.
• Inventors: Nathan, Arokia, Lai, Jackson Chi-Sun, Cha, Suk-Bae, Church, Corbin
• Application Number:
  US15/669,941
• Publication Number:
  US 20170359064A1
• Time in Patent Office: Days
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: G06F 3/04166 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 Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9625 using a force resistance transducer

Abstract

Integrated touch displays with combined pressure and projected capacitance touch capabilities are provided. A sensing electrode layer and, optionally, a driving electrode layer, has a plurality of discrete pads deposited, patterned, printed or laminated on a cover lens or color filter substrate. Each of the discrete pads may be formed of an optically transparent conductor.

Claims

1. A projected capacitance touchscreen device comprising a pressure sensing assembly, the pressure sensing assembly comprising:

a driving electrode layer;

a sensing electrode layer comprising a plurality of conductive traces, wherein each trace comprises one or more sensing pads;

a piezoelectric layer provided between the driving electrode layer and the sensing electrode layer, wherein the piezoelectric layer acts as a dielectric;

a detection circuit operatively connected to the plurality of conductive traces of the sensing electrode layer, wherein the detection circuit is selectively operable in a first mode and a second mode, wherein in the first mode the detection circuit is configured to detect a change in capacitance at one or more of the conductive traces of the sensing layer, and wherein in the second mode the detection circuit is configured to detect a change in electric current at one or more of the conductive traces of the sensing layer.

2. The device of claim 1, wherein the driving electrode layer comprises a biasing layer.

3. The device of claim 1, wherein the driving electrode layer comprises a plurality of conductive traces, and wherein each trace comprises one or more driving pads.

4. The device of claim 3, wherein each conductive trace of the driving electrode layer terminates in a respective one of the one or more driving pads.

5. The device of claim 3, wherein each conductive trace of the driving electrode layer comprises a plurality of driving pads.

6. The device of claim 3, wherein each driving pad is formed of an optically transparent conductive material.

7. The device of claim 1, wherein the one or more sensing pads are shaped to maximize fringing fields and a change in capacitance between the sensing electrode layer and the driving electrode layer in response to stimulus.

8. The device of claim 1, wherein the one or more sensing pads have a polygonal shape.

9. The device of claim 1, wherein the driving electrode layer comprises a plurality of conductive traces, wherein each trace comprises one or more driving pads, and wherein the one or more driving pads are aligned with the one or more sensing pads.

10. The device of claim 9, wherein the one or more driving pads are shaped to maximize fringing fields and a change in capacitance between the sensing electrode layer and the driving electrode layer in response to stimulus.

11. The device of claim 9, wherein the one or more driving pads have a polygonal shape.

12. The device of claim 1, wherein each conductive trace of the sensing electrode layer terminates in a respective one of the one or more sensing pads.

13. The device of claim 12, wherein each conductive trace of the sensing electrode layer further comprises an external portion at a periphery of the device, wherein the external portion is formed of an optically opaque conductive material.

14. The device of claim 1, wherein the one or more sensing pads are formed of an optically transparent conductive material.

15. The device of claim 1, wherein each conductive trace of the sensing electrode layer comprises a plurality of sensing pads.

16. The device of claim 1, further comprising a processor, wherein the processor is configured to interpret pressure data from the one or more sensing pads as an image map.

17. The device of claim 16, wherein the pressure data comprises a plurality of pressure levels, and wherein each pixel in the image map has a respective pressure level mapped as a level of grey.

18. The device of claim 16, wherein he pressure data is interpreted using correlated double sampling.

19. The device of claim 18, wherein the pressure data is interpreted using compressive sensing.