PRESSURE SENSING DISPLAY DEVICE

• US 20130265256A1
• Filed: 04/05/2013
• Published: 10/10/2013
• Est. Priority Date: 04/07/2012
• Status: Abandoned Application

• Current Assignee: Cambridge Touch Technologies, Ltd.
• Original Assignee: Cambridge Touch Technologies, Ltd.
• Inventors: Nathan, Arokia, Lai, Jackson Chi Sun, Church, Corbin, Cha, Suk-Bae
• Application Number:
  US13/857,742
• Publication Number:
  US 20130265256A1
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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

Abstract

A pressure sensing architecture for use with liquid crystal (LC), organic light emitting diode (OLED), electrophoretic, or other similarly fabricated displays. The described architecture includes a bottom TFT structure and a top structure with color filter material, and with liquid crystal, electrophoretic or OLED material provided in between. A piezoelectric or equivalent material is provided within the display assembly. Transmitting and receiving electrodes can be used to electrically bias the piezoelectric or equivalent material, which provides an analog electrical signal in response to incident touch pressure.

Claims

1. A pressure sensing display device, comprising:

a cover layer;

a base layer;

a plurality of display pixels provided above the base layer and below the cover layer;

a plurality of pressure sensing elements provided above the base layer, wherein each of the pressure sensing elements is addressable to provide an output based on a force applied to the pressure sensing element; and

at least one amplifier configured to detect the output of each addressed pressure sensing element and provide an output pressure value.

2. The device of claim 1, wherein an integrated circuit layer is provided above the base layer, and the integrated circuit layer comprises a thin film transistor circuit.

3. The device of claim 1, wherein an output of the pressure sensing element is coupled to an input of the at least one amplifier.

4. The device of claim 1, wherein the at least one amplifier is a charge amplifier, and wherein charge at an output of the pressure sensing element is coupled to an input of the at least one amplifier by an addressing transistor.

5. The device of claim 1, wherein each of the pressure sensing elements further comprises an integrator, and wherein an amplifier output of the integrator is coupled to an input of the at least one amplifier by an addressing transistor.

6. The device of claim 5, wherein an output of a pressure sensing portion of the pressure sensing element is resettable by a reset transistor.

7. The device of claim 5, wherein an output of the at least one amplifier is coupled to an input of a correlated double sampler.

8. The device of claim 1, further comprising an insulating layer provided between the pressure sensing elements and the base layer.

9. The device of claim 1, further comprising an insulating layer provided between multiple layers of pressure sensing elements and the base layer.

10. The device of claim 8, wherein the insulating layer is formed of a dielectric material.

11. The device of claim 10, wherein the dielectric material is selected from the group consisting of aluminum oxide, silicon dioxide and silicon nitride.

12. The device of claim 10, wherein the dielectric material is optically transparent.

13. The device of claim 1, wherein the pressure sensing elements are provided in a layer above the display pixels.

14. The device of claim 1, wherein the pressure sensing elements are provided in a layer below the display pixels.

15. The device of claim 1, wherein the pressure sensing elements are substantially co-planar with the display pixels.

16. The device of claim 1, wherein the display pixels are arranged in a grid, and wherein the pressure sensing elements replace display pixels in the grid at selected intervals.

17. The device of claim 1, wherein the display pixels are arranged in a first grid, and wherein the pressure sensing elements are arranged in a second grid.

18. The device of claim 17, wherein the second grid corresponds to the first grid.

19. The device of claim 1, further comprising a controller, wherein the controller detects a blanking interval of the display pixels, and wherein each pressure sensing element is addressed during the blanking interval.

20. The device of claim 19, wherein the blanking interval is a horizontal blanking interval.

21. The device of claim 19, wherein the blanking interval is a vertical blanking interval.

22. The device of claim 19, wherein the blanking interval is selectively determined by the controller between a horizontal and a vertical blanking interval.

23. A method of pressure sensing in a display device comprising:

providing a plurality of display pixels provided above a base layer and below a cover layer of the display device;

providing a plurality of pressure sensing elements above the base layer;

addressing each of the pressure sensing elements is addressable to provide an output based on a force applied to the pressure sensing element; and

detecting the output of each addressed pressure sensing element at at least one amplifier to provide an output pressure value.