INTEGRATED TOUCH FOR IMOD DISPLAYS USING BACK GLASS

• US 20110149375A1
• Filed: 12/22/2009
• Published: 06/23/2011
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Palmateer, Lauren Fay, Lavery, Kristopher Andrew, Natarajan, Bangalore Ramaswamiengar, Kothari, Manish, Griffiths, Jonathan Charles, Govil, Alok
• Granted Patent: US 8,149,496 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• 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 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

An interferometric modulator (“IMOD”) display utilizes ambient light and incorporates touch sensing without reducing the amount of ambient light that reaches the MEMS modulators, and without introducing any optical distortion or loss of performance. Electrodes for touch sensing are located at a back glass of the inteferometric display, and are used in conjunction with electrodes whose primary function is to activate the pixels of the MEMS display, in order to sense a touch. The touch deflects the IMOD layers and is sensed through the various display layers at the rear of the display.

Claims

1. An apparatus, comprising:

a first substrate;

an array of microelectromechanical elements disposed on the first substrate;

a first plurality of electrodes configured for conducting electrical signals to the array of microelectromechanical elements;

first control circuitry configured to apply electrical signals for controlling the array of microelectromechanical elements via the first plurality of electrodes;

a second substrate;

a second plurality of electrodes disposed on the second substrate; and

second control circuitry configured to detect capacitance changes between the first plurality of electrodes and the second plurality of electrodes caused by a touch on the first substrate and to determine a location of the touch based at least in part by referencing a stored map of centroid capacitance change versus intersection data.

2. The apparatus of claim 1, wherein the array of microelectromechanical elements comprises interferometric modulation elements, the interferometric modulation elements comprising two walls that define a cavity, one of the walls being movable relative to the other through a range of positions, the walls causing the cavity to operate interferometrically in at least one of the positions, producing a predetermined optical response to visible light.

3. The apparatus of claim 1, wherein the first substrate is substantially transparent.

4. The apparatus of claim 1, wherein the second control circuitry is further configured to compute a centroid of detected capacitance changes.

6. The apparatus of claim 1, wherein the second control circuitry is further configured to compute a centroid of a multi point touch.

7. The apparatus of claim 1, wherein the first plurality of electrodes is part of an optical stack disposed on the first substrate.

8. The apparatus of claim 1, wherein the first plurality of electrodes is adjacent the first substrate.

9. The apparatus of claim 8, wherein the first plurality of electrodes is located between the array of microelectromechanical elements and the first substrate.

10. The apparatus of claim 1, wherein multiple adjacent of the first plurality of electrodes are connected together and sensed simultaneously.

11. The apparatus of claim 1, wherein the apparatus comprises:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

12. The apparatus as recited in claim 11, further comprising:

a driver circuit configured to send at least one signal to said display.

13. The apparatus as recited in claim 12, further comprising:

a controller configured to send at least a portion of said image data to said driver circuit.

14. The apparatus as recited in claim 11, further comprising:

an image source module configured to send said image data to said processor.

15. The apparatus as recited in claim 14, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

16. The apparatus as recited in claim 11, further comprising:

an input device configured to receive input data and to communicate said input data to said processor.

5. (canceled)

17. An apparatus comprising:

a first substantially transparent substrate;

an array of interferometric modulation elements disposed on the first substantially transparent substrate, the interferometric modulation elements comprising two walls that define a cavity, one of the walls being movable relative to the other through a range of positions, the walls causing the cavity to operate interferometrically in at least one of the positions, producing a predetermined optical response to visible light;

a first plurality of electrodes oriented along a first axis configured for conducting electrical signals to the array of interferometric modulation elements;

first control circuitry configured to apply electrical signals for controlling the array of interferometric modulation elements via the first plurality of electrodes;

a second plurality of electrodes oriented along a second axis substantially orthogonal to the first axis; and

a touch screen apparatus configured for sensing a touch and an associated change in resistance at an intersection between electrodes of the first and second plurality.

18. (canceled)

19. (canceled)

20. A method of making an interferometric display apparatus, comprising:

forming a front substrate at a front of the display, the front substrate being substantially transparent;

forming a rear substrate at a rear of the display, the rear substrate being substantially transparent;

forming an array of interferometric modulation elements disposed between the front and rear substrates, the array disposed on the front substrate at the front of the display, the interferometric modulation elements comprising two walls that define a cavity, one of the walls being movable relative to the other through a range of positions, the walls causing the cavity to operate interferometrically in at least one of the positions, producing a predetermined optical response to visible light;

forming a first plurality of electrodes oriented along a first axis and configured for conducting electrical signals to the array of interferometric modulation elements, the first plurality of electrodes in contact with the rear substrate;

forming a second plurality of electrodes oriented along a second axis substantially orthogonal to the first axis; and

configuring a touch screen apparatus for using one or both of the first or second plurality of electrodes as plates of a touch screen, for sensing a change in capacitance generated by a touch at an intersection between the electrodes of the first and second plurality and for referencing a stored map of centroid capacitance change vs. intersection data to determine the location of the touch.

25. The method of claim 20, further comprising configuring the touch screen apparatus for computing a centroid of a multi point touch.

26. The method of claim 20, further comprising providing a plurality of posts within the rear substrate.

27. The method of claim 20, wherein the first plurality of electrodes are disposed atop the posts.

28. The method of claim 26, further comprising providing desiccant between the plurality of posts within the substrate.

21-24. -24. (canceled)

29. A method of making an interferometric display apparatus, comprising:

forming an array of interferometric modulators on an array substrate;

forming an absorber layer;

providing a second substrate opposing the array substrate;

providing a matrix of touch sensors on the second substrate;

configuring the interferometric display apparatus to supply a reference voltage to an electrode of the array of interferometric modulators and to detect a change in capacitance between one of the matrix of touch sensors and the electrode of the array; and

attaching the array substrate and the opposing second substrate.

30. The method of claim 29, further comprising forming a top plate electrode.

31. The method of claim 29, further comprising forming posts within the second substrate and providing desiccant between the posts.

32-35. -35. (canceled)