ANGULARLY-SELECTIVE SENSOR-IN-PIXEL IMAGE DETECTION

• US 20110122071A1
• Filed: 11/24/2009
• Published: 05/26/2011
• Est. Priority Date: 11/24/2009
• Status: Active Grant

• Current Assignee: Zhigu Holdings Limited
• Original Assignee: Microsoft Corporation
• Inventors: Powell, Karlton
• Granted Patent: US 8,896,545 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386

Abstract

A display system configured for multi-touch input is provided. The display system comprises a display surface, a local light source to illuminate the display surface with infrared light, and an image-producing display panel. The image-producing display panel comprises a plurality of image sensor pixels positioned within a sensor layer of the image-producing display panel. The image-producing display panel further comprises an angularly-selective layer positioned between the display surface and the sensor layer, wherein the angularly-selective layer is configured to transmit light having a first range of incidence angles with the surface normal of the angularly-selective layer to a first sensor pixel of sensor layer, and to reflect light having a second range of incidence angles from a second sensor pixel of the sensor layer, where the second range is greater than the first range of incidence angles with respect to a surface normal of the sensor layer.

Claims

1. A display system configured for multi-touch input, the display system comprising:

a display surface;

an image-producing display panel comprising;

a plurality of sensor pixels positioned within a sensor layer of the image-producing display panel, and

an angularly-selective layer positioned between the display surface and the sensor layer, the angularly-selective layer configured to transmit infrared light having a first range of incidence angles with a surface normal of the angularly-selective layer to a first sensor pixel of the sensor layer and to reflect infrared light having a second range of incidence angles from a second sensor pixel of the sensor layer, the second range of incidence angles being greater than the first range of incidence angles with respect to a surface normal of the sensor layer; and

a local light source to illuminate the display surface with one or more wavelengths of infrared light.

2. The display system of claim 1, further comprising a rigid, transparent mechanical strength layer configured to direct infrared light reflected from a touch at the display surface to the angularly-selective layer.

3. The display system of claim 1, wherein the angularly-selective layer is configured to transmit more than 85% of incident light having a wavelength of between 400 and 700 nm and having an incidence angle of less than 80 degrees with respect to the surface normal of the angularly-selective layer as measured in air.

4. The display system of claim 1, wherein the light emitted by the local light source is emitted in a wavelength range including one or more wavelengths between 800 and 890 nm.

5. The display system of claim 1, wherein the angularly-selective layer is configured to transmit at least 90% of light incident to the angularly-selective layer within the wavelength range output by the local light source having an incidence angle less than or equal to 10 degrees with respect to the surface normal of the angularly-selective layer as measured in air and wherein the angularly-selective layer is further configured to transmit no more than 15% of light incident to the angularly-selective layer within the wavelength range output by the local light source having an incidence angle of greater than 57 degrees with respect to the surface normal of the angularly-selective layer as measured in air.

6. The display system of claim 1, wherein the angularly-selective layer comprises a film having a periodic composition gradient between a first composition and a second composition of the angularly-selective layer.

7. The display system of claim 1, wherein the angularly-selective layer includes a multi-layer dichroic filter.

8. The display system of claim 7, wherein the multi-layer dichroic filter is patterned to have an array of angularly-selective pixel filters, wherein each angularly-selective pixel filter is optically aligned with a corresponding sensor pixel to filter light incident within a field of view for the corresponding sensor pixel.

9. The display system of claim 1, wherein the local light source comprises an array of light emitting diodes configured to direct infrared light through the sensor layer to illuminate the display surface.

10. The display system of claim 1, wherein the local light source comprises an array of light emitting diodes configured to inject infrared light into a light guide located between the display surface and the sensor layer.

11. An image-producing display panel configured for use with a multi-touch input display system, the image-producing display panel comprising:

a display surface;

a sensor layer comprising an array of sensor pixels configured to capture an image of an object touching the display surface; and

an angularly-selective layer positioned between the display surface and the sensor layer, the angularly-selective layer comprising an array of angularly-selective pixel filters, each angularly-selective pixel optically aligned with a corresponding sensor pixel to filter light incident within a field of view of that sensor pixel, each angularly-selective pixel filter being configured to transmit to a first sensor pixel incidence infrared light having an incidence angle within a first, lower range of incidence angles with respect to a surface normal of the angularly-selective layer, and to reflect from a second sensor pixel incident infrared light having an incidence angle within a second, higher range of incidence angles with respect to the surface normal of the angularly-selective layer.

12. The image-producing display panel of claim 11, where the angularly-selective layer includes a multi-layer dichroic filter.

13. The image-producing display panel of claim 11, wherein the angularly-selective layer is configured to transmit at least 90% of incident infrared light having an incidence angle less than or equal to 10 degrees with respect to a surface normal of the angularly-selective layer as measured in air and wherein the angularly-selective layer is further configured to transmit no more than 15% of incident infrared light having an incidence angle of greater than 57 degrees with respect to the surface normal as measured in air.

14. A method for capturing an image of an object touching a display surface of a display system using a sensor layer included in an image-producing display panel of the display system, the method comprising:

illuminating the display surface with infrared light from a local light source;

receiving infrared light emitted by the local light source and reflected from the object toward the sensor layer at an angularly-selective layer positioned between the sensor layer and the display surface;

transmitting through the angularly-selective layer a first portion of the infrared light having a first range of incidence angles with respect to a surface normal of the angularly-selective layer such that the first portion of infrared light reaches a first sensor pixel of the sensor layer; and

reflecting from the angularly-selective layer a second portion of the infrared light having a second range of incidence angles with respect to the surface normal of the angularly-selective layer.

15. The method of claim 14, further comprising transmitting more than 85% of incident light having a wavelength of between 400 and 700 nm and having an incidence angle of less than 80 degrees with respect to the surface normal of the angularly-selective layer as measured in air.

16. The method of claim 15, where transmitting through the angularly-selective layer a first portion of the infrared light having a first range of incidence angles with respect to the surface normal of the angularly-selective layer such that the first portion of infrared light reaches a first sensor pixel of the sensor layer includes transmitting at least 90% of the first portion of the infrared light having an incidence angle less than or equal to 10 degrees with respect to the surface normal of the angularly-selective layer as measured in air.

17. The method of claim 16, where reflecting from the angularly-selective layer a second portion of the infrared light having a second range of incidence angles with respect to the surface normal of the angularly-selective layer includes reflecting at least 85% of the second portion of the infrared light having an incidence angle of greater than 57 degrees with respect to the surface normal of the angularly-selective layer as measured in air.

18. The method of claim 14, wherein the angularly-selective layer comprises a film having a sinusoidal composition gradient between a first composition and a second composition of the angularly-selective layer.

19. The method of claim 14, wherein the angularly-selective layer includes a multi-layer dichroic filter patterned to have an array of angularly-selective pixel filters, wherein each angularly-selective pixel filter is optically aligned with a corresponding sensor pixel to filter light incidence within a field of view of that sensor pixel.

20. The method of claim 14, wherein illuminating the display surface with infrared light from a local light source includes emitting light in a wavelength range including one or more wavelengths between 800 and 890 nm.