OPTICAL FINGERPRINT SENSOR UNDER A DISPLAY

• US 20170220844A1
• Filed: 06/30/2016
• Published: 08/03/2017
• Est. Priority Date: 01/29/2016
• Status: Active Grant

• Current Assignee: Beijing Jiiov Technology Company Limited
• Original Assignee: Synaptics Incorporated
• Inventors: Jee, Alvin, Klenkler, Richard Andrew, Mackey, Bob Lee, Jones, Eric, Wickboldt, Paul, Smith, Patrick, Lee, Young Seen
• Granted Patent: US 10,268,884 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/1172 using fingerprinting
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: G02B 13/24 for reproducing or copying at short object distances
• CPC Class Codes: G02B 2207/123 Optical louvre elements, e.g. for directional light blocking
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G06F 1/1637 Details related to the display arrangement, including those related to the mounting of the display in the housing
• CPC Class Codes: G06F 1/1684 Constructional details or arrangements related to integrated I/O peripherals not covered by groups G06F1/1635 - G06F1/1675
• 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 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement
• CPC Class Codes: G06V 40/1341 Sensing with light passing through the finger
• CPC Class Codes: G06V 40/1359 Extracting features related to ridge properties; Determining the fingerprint type, e.g. whorl or loop
• CPC Class Codes: G06V 40/15 Biometric patterns based on physiological signals, e.g. heartbeat, blood flow
• CPC Class Codes: H04N 23/54 : Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H10K 59/65 : OLEDs integrated with inorganic image sensors

Abstract

An optical sensor system includes: an input surface providing a sensing region for a biometric object; a plurality of display elements, disposed beneath the input surface, configured to emit light to provide a display; an aperture layer, disposed beneath the plurality of display elements; a collimator layer, disposed beneath the aperture layer; and a plurality of light sensing elements, disposed beneath the collimator layer, wherein the plurality of light sensing elements are configured to detect light from the sensing region that has passed through the aperture layer and the collimator layer.

Claims

1. An optical sensor system, comprising:

an input surface providing a sensing region for a biometric object;

a plurality of display elements, disposed beneath the input surface, configured to emit light to provide a display;

an aperture layer, disposed beneath the plurality of display elements;

a collimator layer, disposed beneath the aperture layer; and

a plurality of light sensing elements, disposed beneath the collimator layer, wherein the plurality of light sensing elements are configured to detect light from the sensing region that has passed through the aperture layer and the collimator layer.

2. The optical sensor system according to claim 1, wherein the plurality of display elements comprise a plurality of light-emitting diodes (LEDs) or organic light-emitting diodes (OLEDs), wherein the plurality of LEDs or OLEDs are a source for the light from the sensing region.

3. The optical sensor system according to claim 1, wherein the input surface is part of a cover lens;

and

wherein the optical sensor system further comprises a polarizer film between the plurality of display elements and the cover lens.

4. The optical sensor system according to claim 1, wherein the collimator layer further comprises:

a gap or a transparent layer; and

a plurality of light-blocking structures forming a collimator beneath the gap or the transparent layer.

5. The optical sensor system according to claim 4, wherein the plurality of light-blocking structures are formed of etched silicon.

6. The optical sensor system according to claim 4, wherein the plurality of light-blocking structures have heights of 100 um or less.

7. The optical sensor system according to claim 4, wherein the plurality of light-blocking structures have vertical walls.

8. The optical sensor system according to claim 4, wherein the plurality of light-blocking structures have slanted walls.

9. The optical sensor system according to claim 1, wherein the aperture layer and the collimator layer are configured to provide an aspect ratio of at least 15:

1 for the light passing through the aperture layer and the collimator layer.

10. The optical sensor system according to claim 1, further comprising:

an auxiliary light source, configured to provide light to the sensing region, wherein the light from the light source is reflected from the sensing region, passed through the aperture layer, and detected by the plurality of light sensing elements.

11. The optical sensor system according to claim 1, wherein the plurality of display elements and the aperture layer are part of a display stack.

12. The optical sensor system according to claim 1, wherein the aperture layer, the collimator layer, and the plurality of light sensing elements are part of an optical biometric sensor attached to a display stack.

13. The optical sensor system according to claim 1, wherein apertures of the aperture layer are aligned to respective light collimating areas of the collimator layer, wherein the light collimating areas are disposed between light blocking portions of the collimator layer.

14. The optical sensor system according to claim 1, wherein the plurality of display elements are formed on a thin-film transistor (TFT) layer;

and

wherein the aperture layer is part of the thin-film transistor (TFT) layer.

15. The optical sensor system according to claim 1, wherein the plurality of display elements are formed on a thin-film transistor (TFT) layer;

and

wherein the TFT layer comprises apertures in addition to the apertures of the aperture layer.

16. The optical sensor system according to claim 1, wherein apertures of the aperture layer are non-circular, and the apertures are oriented such that sides of nearest adjacent apertures are not facing one another.

17. An optical sensor system, comprising:

an input surface providing a sensing region for a biometric object;

a plurality of display elements, disposed beneath the input surface, configured to emit light to provide a display;

a pinhole layer, comprising a plurality of pinholes, disposed beneath the plurality of display elements; and

an image sensor, disposed beneath the pinhole layer, wherein the image sensor is configured to detect a plurality of sub-images corresponding to the biometric object, each sub-image of the plurality of sub-images being projected onto the image sensor by a respective pinhole of the pinhole layer.

18. The optical sensor system according to claim 17, further comprising:

a processing system, configured to combine the detected plurality of sub-images into an image of the biometric object.

19. An optical sensor system, comprising:

an input surface providing a sensing region for a biometric object;

a plurality of display elements, disposed beneath the input surface, configured to emit light to provide a display, wherein the plurality of display elements include sub-pixels corresponding to red light and sub-pixels corresponding to green light;

an image sensor, disposed beneath the plurality of display elements, configured to detect light from the plurality of display elements that is reflected from the sensing region; and

a processor, configured to cause the plurality of display elements to alternately illuminate the biometric object with red light and green light using the plurality of display elements, and to detect, based on detection of red light and green light reflected from the sensing region by the image sensor, a pulse corresponding to the biometric object.

20. The optical sensor system according to claim 19, wherein the processor is further configured to determine, based on the detection of the red light and the green light reflected from the sensing region, an oxygenation level or measure of blood oximetry corresponding to the biometric object.

21. An optical sensor system, comprising:

an input surface providing a sensing region for a biometric object;

a plurality of display elements, disposed beneath the input surface, configured to emit light to provide a display;

an aperture layer, disposed beneath the plurality of display elements, configured to diffract light from the plurality of display elements reflected from the sensing region; and

an image sensor, disposed beneath the aperture layer, wherein the image sensor is configured to detect the diffraction patterns of the diffracted light.

22. The optical sensor system according to claim 21, further comprising:

a collimator layer, configured to limit the diffraction patterns of the diffracted light to a central peak for detection by the image sensor.

23. The optical sensor system according to claim 21, further comprising:

a collimator layer, configured to limit each of the diffraction patterns to a central peak and first-order maxima for detection by the image sensor; and

wherein the system further comprises a processor, configured to deconvolve the limited diffraction patterns detected by the image sensor.

24. A method for producing an optical biometric sensor for a display device, comprising:

forming a display stack, wherein the display stack includes an input surface providing a sensing region for a biometric object and a plurality of display elements configured to emit light to provide a display;

forming a biometric object sensor, the biometric object sensor includes a collimator layer and a plurality of light sensing elements;

forming an aperture layer; and

attaching the biometric object sensor to the display stack.

25. The method according to claim 24, wherein the aperture layer is formed as part of the display stack.

26. The method according to claim 24, wherein the aperture layer is formed as part of the biometric object sensor.

27. A method for using an optical biometric sensor to detect vascular information relating to a biometric object, the method comprising:

illuminating, by a plurality of display elements of a display device, a biometric object above a cover lens of the display device with green and red light in an alternating manner; and

detecting, by a plurality of light sensing elements of the display device, green and red light, respectively, reflected from a sensing region above the cover lens during the illuminating, wherein the reflected light passes through an aperture layer and a collimator layer of the display device before being detected; and

detecting, by a processor of the display device, a pulse corresponding to the biometric object based on the detected green and red light.

28. The method according to claim 27, further comprising:

determining, by the processor, an oxygenation level or measure of blood oximetry corresponding to the biometric object based on the detected green and red light.