Signal strength enhancement in a biometric sensor array

• US 9,542,589 B2
• Filed: 10/12/2015
• Issued: 01/10/2017
• Est. Priority Date: 10/28/2010
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Thammasouk, Khamvong, Lee, Young Seen, Wickboldt, Paul
• Primary Examiner(s): Seth, Manav
• Application Number:
  US14/880,887
• Publication Number:
  US 20160034740A1
• Time in Patent Office: 456 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06K 19/07756 the connection being non-galvanic, e.g. capacitive
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive 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 40/1365 Matching; Classification
• CPC Class Codes: G07C 9/25 using biometric data, e.g. fingerprints, iris scans or voice recognition
• CPC Class Codes: G07C 9/26 using a biometric sensor integrated in the pass
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 27/14678 Contact-type imagers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/15788 Glasses, e.g. amorphous oxides, nitrides or fluorides
• CPC Class Codes: H01L 2924/19105 in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H01L 2924/19107 off-chip wires
• CPC Class Codes: H04L 9/3231 Biological data, e.g. fingerprint, voice or retina network architectures or network communication protocols for supporting authentication of entities using biometrical features in a packet data network H04L63/0861
• CPC Class Codes: H04N 21/4415 using biometric characteristics of the user, e.g. by voice recognition or fingerprint scanning cryptography using biological data H04L9/3231; authentication in networks using biometric H04L63/0861

Abstract

A biometric imager may comprise a plurality of sensor element traces formed in or on a sensor substrate which may comprise at least a portion of a display screen defining a biometric sensing area and forming in-active pixel locations; an auxiliary active circuit formed in or on the sensor substrate on the periphery of the biometric sensing area and in direct or indirect electrical contact with the sensor element traces; and providing a signal processing interface to a remotely located controller integrated circuit. The sensor element traces may form a portion of one dimensional linear sensor array or pixel locations in a two dimensional grid array capacitive gap biometric imaging sensor. The auxiliary circuit may provide pixel location selection or pixel signal amplification. The auxiliary circuit may be mounted on a surface of the display screen. The auxiliary circuit further comprising a separate pixel location selection controller circuit.

Claims

1. A biometric object image sensor comprising:

a plurality of capacitive gap sensor electrode traces formed on a glass substrate, wherein the plurality of capacitive gap sensor electrode traces form an array of biometric sensor imaging pixel locations within a biometric sensing area of the biometric image sensor, wherein at least one of the capacitive gap sensor electrode traces comprises a transmitter electrode trace and at least one of the capacitive gap sensor electrode traces comprises a receiver electrode trace, wherein a change in a resulting signal received by the receiver electrode trace is indicative of a biometric image characteristic at a respective pixel location in the array of biometric sensor imaging pixel locations; and

a controller integrated circuit (IC) mounted to the glass substrate, wherein the controller IC is in electrical contact with the plurality of capacitive gap sensor electrode traces.

2. The biometric object image sensor of claim 1, wherein the plurality of capacitive gap sensor electrode traces form a two-dimensional grid array of biometric sensor imaging pixel locations within the biometric sensing area.

3. The biometric object image sensor of claim 2, wherein the controller IC is mounted on the glass substrate away from the two-dimensional grid array and outside of the biometric sensing area.

4. The biometric object image sensor of claim 2, wherein the controller IC is mounted over the two-dimensional grid array on the glass substrate and within the biometric sensing area.

5. The biometric object image sensor of claim 1, wherein the controller IC is flip chip mounted over the glass substrate.

6. The biometric object image sensor of claim 1, wherein the glass substrate provides a glass button.

7. The biometric object image sensor of claim 1, wherein the glass substrate provides a cover glass for a mobile device.

8. The biometric object image sensor of claim 1, further comprising:

a molding or filling compound that seals in the controller IC.

9. The biometric object image sensor of claim 1, further comprising:

a molding or filling compound that seals in the controller IC and sides of the glass substrate.

10. The biometric object image sensor of claim 1, further comprising:

a molding compound that seals in the controller IC; and

electrical contacts formed on a first side of the molding compound, wherein the first side of the molding compound is opposite to an exposed side of the glass substrate.

11. The biometric object image sensor of claim 10, wherein the exposed side of the glass substrate provides a surface for a user to place or swipe a finger over the biometric sensing area of the biometric image sensor.

12. The biometric object image sensor of claim 1, further comprising:

a dielectric island positioned at a crossover point between the transmitter electrode trace and the receiver electrode trace, wherein the dielectric island separates the transmitter electrode trace from the receiver electrode trace.

13. The biometric object image sensor of claim 1, wherein the plurality of capacitive gap sensor electrode traces comprises a plurality of transmitter electrode traces and a plurality of receiver electrode traces forming a two-dimensional array of crossover points within the biometric sensing area of the biometric image sensor;

wherein a pattern of dielectric islands are positioned at the crossover points between the plurality of transmitter electrode traces and the plurality of receiver electrode traces;

wherein the pattern of dielectric islands separates the plurality of transmitter electrode traces from the plurality of receiver electrode traces.

14. A fingerprint imaging sensor comprising:

a plurality of capacitive gap sensor electrode traces formed on a glass substrate, wherein the plurality of capacitive gap sensor electrode traces form a two-dimensional array of fingerprint imaging pixel locations within a fingerprint sensing area of the fingerprint imaging sensor, wherein a first plurality of the capacitive gap sensor electrode traces comprises a plurality of transmitter electrode traces and a second plurality of the capacitive gap sensor electrode traces comprises a plurality of receiver electrode traces crossing over the plurality of transmitter electrode traces, wherein changes in resulting signals received by the plurality of receiver electrode traces are indicative of fingerprint image characteristics at the array of fingerprint imaging pixel locations;

a plurality of dielectric islands between the plurality of transmitter electrode traces and the plurality of receiver electrode traces, wherein each dielectric island of the plurality of dielectric islands separates a respective transmitter electrode trace of the plurality of transmitter electrode traces from a respective receiver electrode trace of the plurality of receiver electrode traces at a crossover point therebetween;

a controller integrated circuit (IC) mounted to the glass substrate, wherein the controller IC is in electrical contact with the plurality of capacitive gap sensor electrode traces, wherein the controller IC is mounted away from the two dimensional array of biometric sensor imaging pixel locations and outside of the biometric sensing area; and

a molding compound encapsulating the controller IC.

15. A method of making a biometric object imaging sensor, the method comprising:

providing a glass substrate;

depositing a first metal layer over the glass substrate, wherein the first metal layer is patterned into a first plurality of capacitive gap sensor electrode traces;

depositing a first dielectric layer over the first metal layer, wherein the first dielectric layer is patterned into a plurality of isolation islands;

depositing a second metal layer over the first dielectric layer, wherein the second dielectric layer is patterned into a second plurality of capacitive gap sensor electrode traces;

depositing a second dielectric layer over the second metal layer;

planarizing the second dielectric layer; and

bonding a controller integrated circuit (IC) over the glass substrate.

16. The method of claim 15, further comprising:

cutting the glass substrate into a plurality of glass buttons after bonding the controller IC.

17. The method of claim 15, wherein the first plurality of capacitive gap sensor electrode traces comprise a plurality of transmitter electrode traces, and the second plurality of capacitive gap sensor electrode traces comprise a plurality of receiver electrode traces.

18. The method of claim 15, further comprising:

encapsulating the controller IC with a molding compound.