Multi-layer optical designs of under-screen optical sensor module having spaced optical collimator array and optical sensor array for on-screen fingerprint sensing

• US 10,331,939 B2
• Filed: 07/05/2018
• Issued: 06/25/2019
• Est. Priority Date: 07/06/2017
• Status: Active Grant

• Current Assignee: Shenzhen Goodix Technology Co., Ltd.
• Original Assignee: Shenzhen Goodix Technology Co., Ltd.
• Inventors: He, Yi, Pi, Bo
• Primary Examiner(s): Shin, Soo
• Application Number:
  US16/028,399
• Publication Number:
  US 20190012512A1
• Time in Patent Office: 355 Days
• Field of Search: None
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06V 10/96 Management of image or video recognition tasks
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• 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 40/1365 Matching; Classification
• CPC Class Codes: G06V 40/1376 Matching features related to ridge properties or fingerprint texture
• CPC Class Codes: G06V 40/1382 Detecting the live character of the finger, i.e. distinguishing from a fake or cadaver finger
• CPC Class Codes: G06V 40/1388 using image processing
• CPC Class Codes: G06V 40/1394 using acquisition arrangements
• CPC Class Codes: H01L 27/14678 Contact-type imagers
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens
• CPC Class Codes: H10K 59/65 OLEDs integrated with inorganic image sensors

Abstract

Devices and optical sensor modules are provided for provide on-screen optical sensing of fingerprints by using an under-LCD or OLED screen optical sensor module that captures and detects returned light.

Claims

1. An electronic device capable of detecting a fingerprint by optical sensing, comprising;

a liquid crystal display (LCD) screen that provides touch sensing operations and includes a LCD display panel structure to display images;

a LCD backlighting light module coupled to the LCD screen to produce backlghting light to the LCD screen for display images;

a top transparent layer formed over the LCD screen as an interface for being touched by a user for the touch sensing operations and for transmitting the light from the display structure to display images to a user;

an optical sensor module, located below the LCD screen and below the top transparent layer, and structured to include an optical sensor array to receive probe light that is reflected from the top transparent layer and passes through the LCD screen to detect the fingerprint;

one or more probe light sources, separate from the LCD backlighting light module, located under the LCD display panel structure, to produce the probe light that passes through the LCD display panel structure to illuminate a designated fingerprint sensing area on the a top transparent layer to be visibly different from a surrounding area of the top transparent layer for a user to place a finger for optical fingerprint sensing; and

a device control module coupled to the optical sensor module to process an output of the optical sensor module to determine whether a detected fingerprint by the optical sensor module matches an authorized user fingerprint, in addition to optically detecting the fingerprint, detect a biometric parameter different from the detected fingerprint by optical sensing to indicate whether a touch at the top transparent layer associated with the detected fingerprint is from a live person,

wherein the optical sensor module includes one or more optical filtering layers to transmit probe light for optical sensing of the fingerprint while blocking background day light at optical wavelengths longer than the probe light, and wherein the optical sensor module includes one or more layers between the LCD screen and the optical sensor array to be within a predetermined thickness to reduce an effect of Moiré

patterns on the detected fingerprint.

2. The device as in claim 1, wherein:

the one or more probe light sources produces the probe light at different optical wavelengths so that the optical sensor module captures optical properties in reflected probe light by an object in contact with the designated fingerprint sensing area on the top transparent layer at the different optical wavelengths, and

the device control module is operable to process the captured optical properties in reflected probe light by the object at the different optical wavelengths to determine whether the object is a finger of a live person.

3. The device as in claim 1, wherein:

the LCD display panel structure includes a light diffuser layer that diffuses light and the light diffuser includes holes at a selected area above the optical sensor module to allow light to be transmitted to reach the optical sensor module.

4. The device as in claim 1, wherein:

the LCD display panel structure includes a light diffuser layer that diffuses light and the light diffuser layer includes a selected area above the optical sensor module that diffuses less light than other parts of the light diffuser layer to allow more light to transmit through to reach the optical sensor module.

5. The device as in claim 1, comprising:

an optical reflector layer formed on a bottom region of the LCD display panel to reflect light back to the LCD display panel structure;

holes formed in a selected area above the optical sensor module to allow light to be transmitted to reach the optical sensor module.

6. The device as in claim 1, wherein:

the device control module is configured to operate the one or more probe light sources to intermittently emit the probe light, while turning off power to the LCD display panel structure, when the LCD display panel structure is in the sleep mode, to direct the intermittently probe light to the designated fingerprint sensing region of the top transparent layer for monitoring whether there is a person'"'"'s skin in contact with the designated fingerprint sensing region for waking up the device from the sleep mode.

7. The device as in claim 1, wherein:

the device control module coupled to the optical sensor module to receive information on multiple detected fingerprints obtained from sensing a touch of a finger, and the device control module measures a change in the multiple detected fingerprints and determines a touch force that causes the measured change.

8. The device as in claim 7, wherein:

the change includes a change in the fingerprint image due to the touch force, a change in the touch area due to the touch force, or a change in spacing of fingerprint ridges.

9. The device as in claim 1, wherein:

the optical sensor module includes an optical collimator array of optical collimators that receives the probe light and the optical sensor array of optical sensors is placed to receive the probe light from the optical collimator array, and

the optical collimators include a substrate having an array of through holes formed in the substrate as the optical collimators.

10. The device as in claim 1, wherein:

the optical sensor module includes an optical collimator array of optical collimators that receives the probe light and an optical sensor array of optical sensors to receive the probe light from the optical collimator array, and

the optical collimators include an array of optical waveguides or optical fibers.

11. The device as in claim 1, wherein:

the optical sensor module includes an optical collimator array of optical collimators that receives the probe light and an optical sensor array of optical sensors to receive the probe light from the optical collimator array, and

the optical collimators include a micro lens array of micro lenses and each micro lens focuses received light without imaging the received light.

12. The device as in claim 1, wherein:

the LCD screen includes a light diffuser layer that is configured to include a selected area that includes light transmission paths to allow reflected light from the top transparent layer above the LCD screen to transmit through to reach the optical sensor module.

13. The device as in claim 1, wherein:

the LCD display panel structure includes one or more backlight enhancement film layers each including an optical polarized prism structure having two sets of prism grooves that are perpendicular to each other; and

the one or more probe light sources and the optical sensor module under the LCD display panel structure are arranged so that the optical sensor module receives the reflected probe light that is reflected from the top transparent layer and produced by the one or more probe light sources at a direction that is different from a direction of a prism groove.

14. An electronic device capable of detecting a fingerprint by optical sensing, comprising:

a display pan&

that includes light emitting display pixels, each pixel operable to emit light for forming a portion of a display image;

a top transparent layer formed over the display panel as an interface for being touched by a user and for transmitting the light from the display panel to display images; and

an optical sensor module located below the display panel to receive light that is emitted by at least a portion of the light emitting display pixels and is returned from the top transparent layer to detect the fingerprint, the optical sensor module including an optical sensor array of optical detectors, an array of optical collimators located between the display panel and the optical sensor array to collect the returned light from the display panel and to separate light from different locations in the top transparent layer while directing the collected returned light to the optical sensor array,

wherein the optical sensor module includes one or more optical filtering layers to transmit probe light for optical sensing of the fingerprint while blocking background day light at optical wavelengths longer than the probe light, wherein the probe light is separate from a liquid crystal display (LCD) backlight, and wherein the optical sensor module includes a first layer between the display panel and the optical collimator array and a second layer between the optical collimator array and the optical sensor array so that both first and second layers are within a predetermined thickness to reduce an effect of Moiré

patterns on the detected fingerprint.

15. The device as in claim 14, wherein:

the optical sensor module includes an optical layer between the optical collimators and the display panel to select angled probe light returned from the display panel to enter the optical collimators while reducing an amount of the returned probe light that is perpendicular to the display panel and enters the optical collimators.

16. The device as in claim 15, wherein the optical layer includes an optical diffraction pattern that diffracts the returned probe light to direct the angled probe light returned from the display panel to enter the optical collimators.

17. The device as in claim 15, wherein the optical collimators are elongated channels in a direction perpendicular to the display panel and the optical layer between the optical collimators and the display is structured to direct the angled probe light from the display panel to be substantially perpendicular to the display panel to enter the optical collimators while directing a portion of the probe light from the display panel that is perpendicular to the display panel to be away from the direction of the optical collimators.

18. The device as in claim 14, further comprising:

a device electronic control module coupled to the display panel structure to supply power to the light emitting display pixels and to turn off power to the light emitting display pixels in a sleep mode, and

wherein the device electronic control module is configured to wake up the display panel structure from the sleep mode when the optical sensor module detects the presence of a person'"'"'s skin.

19. The device as in claim 14, wherein:

the optical sensor module is configured to, in addition to detecting fingerprints, also detect a biometric parameter different a detected fingerprint to indicate whether a touch at the top transparent layer associated with the detected fingerprint is from a live person; and

the device further includes a device electronic control module configured to grant a user'"'"'s access to the device if;

a detected fingerprint matches a fingerprint an authorized user, and

the detected biometric parameter indicates the detected fingerprint is from a live person.

20. The device as in claim 14, wherein:

two or more optical filtering layers are present to transmit probe light for optical sensing of fingerprints while blocking background day light at optical wavelengths longer than the probe light, and

an optical absorbing material between two adjacent optical filtering layers to absorb light in a rejected light band of the two adjacent optical filtering layers so that bouncing light between the two optical filtering layers is absorbed by the optical absorbing material.

21. The device as in claim 14, wherein:

the optical collimator array includes a periodic pattern that is misaligned to another periodic pattern of the display panel to reduce undesired Moiré

fringes.

22. The device as in claim 21, wherein:

the periodic pattern is rotated at an angle with respect to the other periodic pattern of the display panel to reduce undesired Moiré

fringes.

23. An electronic device capable of detecting a fingerprint by optical sensing, comprising:

a display panel that displays images;

a top transparent layer formed over the display panel as an interface for being touched by a user and for transmitting the light from the display panel to display images;

a protection layer engaged to a bottom of the display panel and shaped to include an opening;

an optical collimator interfacing layer located inside the opening of the protection layer and engaged to a bottom of the display panel within the opening;

an optical collimator array that is located within the opening of the protection layer and is engaged to the optical collimator interfacing layer to receive light is returned from the top transparent layer to detect the fingerprint;

an optical sensor array of optical detectors located below the display panel and spaced from the optical collimator array to collect the returned light from the display panel via the optical collimator array, wherein the optical sensor array is engaged to the protection layer to hold the optical sensor array below the optical collimator array; and

one or more optical filtering layers to transmit probe light for optical sensing of the fingerprint while blocking background day light at optical wavelengths longer than the probe light, wherein the probe light is separate from a liquid crystal display (LCD) backlight,

wherein the optical collimator interfacing layer and spacing between the optical collimator array and the optical sensor array are within a predetermined thickness to reduce an effect of Moiré

patterns on the detected fingerprint.

24. The device as in claim 23, wherein the space between the optical collimator array and the optical sensor array includes an air gap.

25. The device as in claim 23, wherein the space between the optical collimator array and the optical sensor array includes a filling material.

26. The device as in claim 23, wherein:

the optical collimator array includes a periodic pattern that is misaligned to another periodic pattern of the display panel to reduce undesired Moiré

fringes.

27. The device as in claim 26, wherein:

the periodic pattern is rotated at an angle with respect to the other periodic pattern of the display panel to reduce undesired Moiré

fringes.

28. The device as in claim 26, wherein:

the optical sensor module includes an optical layer between the optical collimators and the display panel to select angled probe light returned from the display panel to enter the optical collimators while reducing an amount of the returned probe light that is perpendicular to the display panel and enters the optical collimators.

29. The device as in claim 23, wherein the display panel is an OLED display panel.

30. The device as in claim 23, wherein the display panel is a LCD display panel.