Ultrasonic fingerprint sensor with a contact layer of non-uniform thickness
地域：
CA
CA San Jose
摘要
An ultrasonic sensor includes a two-dimensional array of ultrasonic transducers, wherein the two-dimensional array of ultrasonic transducers is substantially flat, a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers, and an array controller configured to control activation of ultrasonic transducers during an imaging operation. During the imaging operation, the array controller is configured to control a transmission frequency of activated ultrasonic transducers during the imaging operation, wherein a plurality of transmission frequencies are used during the imaging operation to account for an impact of an interference pattern caused by the non-uniform thickness of the contact layer, and is configured to capture at least one fingerprint image using the plurality of transmission frequencies.
說(shuō)明書(shū)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
This application claims also priority to and the benefit of co-pending U.S. Provisional Patent Application 62/875,479, filed on Jul. 17, 2019, entitled “FINGERPRINT IMAGING UNDER CURVED SURFACE,” by Quy Chau et al., having Attorney Docket No. IVS-921-PR, and assigned to the assignee of the present application, which is incorporated herein by reference in its entirety.
Fingerprint sensors have become ubiquitous in mobile devices as well as other applications for authenticating a user's identity. They provide a fast and convenient way for the user to unlock a device, provide authentication for payments, etc. Current fingerprint sensors are typically area sensors that obtain a two-dimensional image of the user's finger area presented to the sensor. Different technologies can be used to image the finger such as capacitive, ultrasound, and optical sensing. Once an image is obtained, that image is processed by a matcher to extract features and to compare against stored images to authenticate the user. As such, accuracy of captured images is essential to the performance of image matching for user authentication.
The accompanying drawings, which are incorporated in and form a part of the Description of Embodiments, illustrate various embodiments of the subject matter and, together with the Description of Embodiments, serve to explain principles of the subject matter discussed below. Unless specifically noted, the drawings referred to in this Brief Description of Drawings should be understood as not being drawn to scale. Herein, like items are labeled with like item numbers.
權(quán)利要求
What is claimed is:1. An ultrasonic sensor comprising:a two-dimensional array of ultrasonic transducers, wherein the two-dimensional array of ultrasonic transducers is substantially flat; a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers; and an array controller configured to control activation of ultrasonic transducers during an imaging operation, the array controller is configured to:control a transmission frequency of activated ultrasonic transducers during the imaging operation, wherein a plurality of transmission frequencies are used during the imaging operation to account for an impact of an interference pattern caused by the non-uniform thickness of the contact layer; and capture a plurality of portions of a fingerprint image using the plurality of transmission frequencies such that each portion of the plurality of portions of the fingerprint image is captured using one transmission frequency of the plurality of transmission frequencies. 2. The ultrasonic sensor of claim 1 , wherein the array controller is configured to capture a plurality of fingerprint images using the plurality of transmission frequencies. 3. The ultrasonic sensor of claim 2 , wherein the plurality of fingerprint images are captured at different temperatures and wherein the transmission frequency is controlled based on the temperature. 4. The ultrasonic sensor of claim 1 , wherein the array controller is further configured to combine the plurality of fingerprint images into a single output fingerprint image, wherein the single output fingerprint image reduces the impact of the interference pattern caused by the non-uniform thickness of the contact layer. 5. The ultrasonic sensor of claim 4 , wherein the array controller is configured to combine the plurality of fingerprint images into a single output fingerprint image by averaging the plurality of fingerprint images. 6. The ultrasonic sensor of claim 4 , wherein the array controller is configured to combine the plurality of fingerprint images into a single output fingerprint image by combining the plurality of fingerprint images using convolution. 7. The ultrasonic sensor of claim 1 , wherein the array controller is configured to combine the plurality of portions of the fingerprint image to generate the fingerprint image. 8. The ultrasonic sensor of claim 7 , wherein the plurality of transmission frequencies provide constructive interference for corresponding portions of the plurality of portions of the fingerprint image during the imaging operation. 9. The ultrasonic sensor of claim 1 , wherein portions of the plurality of portions comprise a plurality of pixels. 10. The ultrasonic sensor of claim 1 , wherein portions of the plurality of portions comprise a single pixel. 11. The ultrasonic sensor of claim 1 , wherein a transmission frequency for each portion of the plurality of portions is determined according to a corresponding thickness of a region of the contact layer associated with each portion of the plurality of portions. 12. The ultrasonic sensor of claim 11 , wherein groups of portions of the plurality of portions having a same corresponding thickness of the region of the contact layer associated with the groups of portions use a same transmission frequency and wherein groups of portions of the plurality of portions having a different corresponding thickness of the region of the contact layer associated with the groups of portions use a different transmission frequency. 13. A method for generating an image at an ultrasonic sensor, the method comprising:performing an imaging operation at an ultrasonic sensor comprising a two-dimensional array of ultrasonic transducers and a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers, wherein the two-dimensional array of ultrasonic transducers is substantially flat, comprising:controlling a transmission frequency of activated ultrasonic transducers during the imaging operation, wherein a plurality of transmission frequencies are used during the imaging operation to account for an impact of an interference pattern caused by the non-uniform thickness of the contact layer; and capturing a plurality of portions of a fingerprint image using the plurality of transmission frequencies such that each portion of the plurality of portions of the fingerprint image is captured using one transmission frequency of the plurality of transmission frequencies. 14. The method of claim 13 , wherein the capturing the plurality of portions of a fingerprint image using the plurality of transmission frequencies comprises:capturing a plurality of fingerprint images using the plurality of transmission frequencies. 15. The method of claim 14 , wherein the plurality of transmission frequencies operate to cancel out the interference pattern of the plurality of fingerprint images. 16. The method of claim 14 , the method further comprising:combining the plurality of fingerprint images into a single output fingerprint image, wherein the single output fingerprint image reduces the impact of the interference pattern caused by the non-uniform thickness of the contact layer. 17. The method of claim 16 , wherein the combining the plurality of fingerprint images into the single output fingerprint image comprises:combining the plurality of fingerprint images into a single output fingerprint image by averaging the plurality of fingerprint images. 18. The method of claim 16 , wherein the combining the plurality of fingerprint images into the single output fingerprint image comprises:combining the plurality of fingerprint images into a single output fingerprint image by combining the plurality of fingerprint images using convolution. 19. The method of claim 13 , further comprising:combining the plurality of portions of the fingerprint image to generate the fingerprint image. 20. The method of claim 19 , wherein the plurality of transmission frequencies provide constructive interference for corresponding portions of the plurality of portions of the fingerprint image during the imaging operation. 21. The method of claim 13 , wherein portions of the plurality of portions comprise a plurality of pixels. 22. The method of claim 13 , wherein portions of the plurality of portions comprise a single pixel. 23. A non-transitory computer readable storage medium having computer readable program code stored thereon for causing a computer system to perform a method for generating an image at an ultrasonic sensor, the method comprising:performing an imaging operation at an ultrasonic sensor comprising a two-dimensional array of ultrasonic transducers and a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers, wherein the two-dimensional array of ultrasonic transducers is substantially flat, comprising:controlling a transmission frequency of activated ultrasonic transducers during the imaging operation, wherein a plurality of transmission frequencies are used during the imaging operation to account for an impact of an interference pattern caused by the non-uniform thickness of the contact layer; capturing a plurality of portions of a fingerprint image using the plurality of transmission frequencies such that each portion of the plurality of portions of the fingerprint image is captured using one transmission frequency of the plurality of transmission frequencies; and combining the plurality of portions of the fingerprint image to generate the fingerprint image.
意見(jiàn)反饋
使用該功能遇到問(wèn)題
該功能需要專業(yè)版企業(yè)版VIP權(quán)限，您可以：
您也可以聯(lián)系官方QQ: 2157717237 電話: 13264338900