COVER-GLASS OPTICAL ISOLATION FOR OPTICAL TOUCH AND FINGERPRINT SENSING

• US 20170109561A1
• Filed: 10/17/2016
• Published: 04/20/2017
• Est. Priority Date: 10/19/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Alam, Khurshid, Wyrwas, John, Gousev, Evgeni
• Granted Patent: US 10,157,305 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06F 2203/0338 Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06V 40/12 Fingerprints or palmprints
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger
• CPC Class Codes: G06V 40/1365 Matching; Classification

Abstract

Methods, systems, computer-readable media, and apparatuses for cover-glass optical isolation for optical touch and fingerprint sensing are presented. One disclosed display assembly includes a cover glass layer; a low refractive index (LRI) layer coupled to a surface of the cover glass layer; a display layer coupled to the LRI layer; a prism structure; and a camera comprising an image sensor optically coupled to the prism structure to capture an image of a fingerprint based on light reflected from a fingertip and propagated within the cover glass layer and directed towards the camera using the prism structure, wherein the cover glass layer defines an overhang region that extends beyond the LRI layer and the display layer, and wherein the prism structure is coupled to the surface of the cover glass layer on the overhang region.

Claims

1. A display assembly comprising:

a cover glass layer;

a low refractive index (LRI) layer coupled to a surface of the cover glass layer;

a display layer coupled to the LRI layer;

a prism structure; and

a camera comprising an image sensor optically coupled to the prism structure to capture an image of a fingerprint based on light reflected from a fingertip and propagated within the cover glass layer and directed towards the camera using the prism structure,

wherein the cover glass layer defines an overhang region that extends beyond the LRI layer and the display layer, and wherein the prism structure is coupled to the surface of the cover glass layer on the overhang region.

2. The display assembly of claim 1, wherein the display layer comprises:

a touch input layer coupled to the LRI layer; and

a display coupled to the touch input layer.

3. The display assembly of claim 2, wherein the touch input layer comprises a capacitive touch sensor or a projected capacitive touch sensor.

4. The display assembly of claim 1, wherein the display layer is coupled to the LRI layer by an optically-clear resin (“

OCR”

) or an optically-clear adhesive (“

OCA”

).

5. The display assembly of claim 1, wherein the cover glass layer has a first refractive index and the LRI layer has a second refractive index lower than the first refractive index.

6. The display assembly of claim 5, wherein a difference between the first and second refractive indices is at least approximately 0.09.

7. The display assembly of claim 5, wherein the second refractive index is between approximately 1.30 and 1.41.

8. An apparatus comprising:

means for propagating light within a display assembly;

means for capturing an image based on light received from the means for propagating light within a display assembly;

means for directing propagating light onto the means for capturing an image coupled to a surface of an overhang region of the means for propagating light; and

a means for displaying coupled to the means for propagating light.

9. The apparatus of claim 8, further comprising means for touch input coupled to the means for propagating light.

10. The apparatus of claim 8, further comprising a means for touch input.

11. The apparatus of claim 10, wherein the means for touch input comprises a capacitive touch sensor or a projected capacitive touch sensor.

12. The apparatus of claim 8, wherein the means for propagating light comprises:

a cover glass means; and

a low refractive index (LRI) means coupled to a surface of the cover glass means.

13. The apparatus of claim 12, wherein the means for directing propagating light is coupled to a surface of the cover glass means.

14. The apparatus of claim 12, wherein the cover glass means has a first refractive index and the LRI means has a second refractive index lower than the first refractive index.

15. The apparatus of claim 14, wherein a difference between the first and second refractive indices is at least approximately 0.09.

16. The apparatus of claim 14, wherein the second refractive index is between approximately 1.30 and 1.41.

17. The apparatus of claim 8, wherein the means for displaying is coupled to the means for propagating light by an optically-clear resin (“

OCR”

) or an optically-clear adhesive (“

OCA”

).

18. A method for forming a display assembly, comprising

providing a display and a cover glass;

applying a low refractive index (LRI) layer to a first portion of a surface of the cover glass;

coupling the display to the LRI layer using at least one of an optically-clear resin (OCR) or an optically-clear adhesive (OCA), wherein coupling the display to the LRI layer defines an overhang region of the cover glass;

coupling a first surface of a prism structure to the surface of the cover glass on the overhang region;

positioning a camera adjacent to a second surface of the prism structure, the camera comprising an image sensor, and

orienting the camera to position the image sensor in to capture light propagating through the second surface of the prism structure.

19. The method of claim 18, further comprising coupling the display assembly to a computing device.

20. The method of claim 18, wherein coupling the display to the LRI layer comprises coupling the display to a touch input layer and coupling the touch input layer to the LRI layer.

21. The method of claim 18, wherein applying the LRI layer comprises one of applying a tape or lamination layer or by using dip coating or spin-on coating process.

22. The method of claim 18, wherein the cover glass has a first refractive index and the LRI layer has a second refractive index lower than the first refractive index.

23. The method of claim 22, wherein a difference between the first and second refractive indices is at least approximately 0.09.

24. The method of claim 22, wherein the second refractive index is between approximately 1.30 and 1.41.

25. A computing device comprising:

a non-transitory computer-readable medium;

a processor in communication with the non-transitory computer-readable medium; and

a display assembly in communication with the processor, the display assembly comprising;

a cover glass layer;

a low refractive index (LRI) layer coupled to a surface of the cover glass layer;

a display layer coupled to the LRI layer;

a prism structure; and

a camera comprising an image sensor optically coupled to the prism structure to capture an image of a fingerprint based on light reflected from a fingertip and propagated within the cover glass layer and directed towards the camera using the prism structure,

wherein the cover glass layer defines an overhang region that extends beyond the LRI layer and the display layer, and wherein the prism structure is coupled to the surface of the cover glass layer on the overhang region.

26. The computing device of claim 25, wherein the display layer comprises:

a touch input layer; and

a display coupled to the touch input layer;

wherein the touch input layer is coupled to the LRI layer.

27. The computing device of claim 25, wherein the computing device comprises a handheld device, a computer monitor, or a television.

28. The computing device of claim 25, wherein the cover glass layer has a first refractive index and the LRI layer has a second refractive index lower than the first refractive index.

29. The computing device of claim 28, wherein a difference between the first and second refractive indices is at least approximately 0.09.

30. The computing device of claim 28, wherein the second refractive index is between approximately 1.30 and 1.41.