Display with peripherally configured ultrasonic biometric sensor

• US 9,323,393 B2
• Filed: 11/04/2013
• Issued: 04/26/2016
• Est. Priority Date: 06/03/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Djordjev, Kostadin Dimitrov, Fennell, Leonard Eugene, Buchan, Nicholas Ian, Burns, David William, Gupta, Samir K., Bae, Sanghoon
• Primary Examiner(s): Chang, Kent
• Assistant Examiner(s): Rosario, Nelson
• Application Number:
  US14/071,362
• Publication Number:
  US 20140354596A1
• Time in Patent Office: 904 Days
• Field of Search: 345168-179
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

Various techniques and apparatuses are disclosed that provide for pixelated display modules that integrate an ultrasonic fingerprint or biometric sensing capability. In some implementations, the ultrasonic fingerprint sensor and the display components of the display module may share a common backplane. In some implementations, the ultrasonic fingerprint sensor may share a flex cable with other components in the display module. In some implementations, the ultrasonic fingerprint sensor may leverage conductive traces on a cover glass used to provide for touch input to the display module.

Claims

1. A display module comprising:

a thin-film transistor (TFT) backplane including;

a substrate with a first side and an opposing second side,

an array of display pixel circuits located on the first side, each display pixel circuit configured to cause a display pixel of a display device connectable to the TFT backplane to change light-emitting, light-transmitting, or light-reflecting states, and

an array of sensor pixel circuits located on the first side, each sensor pixel circuit configured to form part of a piezoelectric ultrasonic fingerprint sensor circuit and configured to read a charge provided to the piezoelectric ultrasonic fingerprint sensor circuit from an array location in the array of sensor pixel circuits, wherein

the array of display pixel circuits and the array of sensor pixel circuits occupy non-overlapping areas of the TFT backplane;

one or more display components positioned between the cover glass and the TFT backplane, the one or more display components configured to, in conjunction with the array of display pixel circuits, provide display functionality for the display module; and

a piezoelectric ultrasonic fingerprint sensor, wherein;

the display module has an active display area defined by the maximum extents of the array of display pixel circuits,

the piezoelectric ultrasonic fingerprint sensor is located outside of the active display area,

at least part of the piezoelectric ultrasonic fingerprint sensor is located between the TFT backplane and the cover glass,

the array of sensor pixel circuits forms part of the piezoelectric ultrasonic fingerprint sensor, and

the piezoelectric ultrasonic fingerprint sensor includes one or more layers of material such that a surface of the piezoelectric ultrasonic fingerprint sensor furthest from the TFT backplane is at the same distance from the TFT backplane as a surface of the one or more display components furthest from the TFT backplane.

2. The display module of claim 1, wherein the fingerprint sensor is sized to capture fingerprints from at least two fingers simultaneously.

3. The display module of claim 1, wherein the piezoelectric ultrasonic biometric sensor is a palmprint sensor.

4. The display module of claim 1, further comprising a single sensor pixel circuit separate from the array of sensor pixel circuits, the single pixel circuit configured to perform as an ultrasonic button.

5. The display module of claim 1, further comprising an array of pixel input electrodes, wherein:

each pixel input electrode overlays a sensor pixel circuit in the array of sensor pixel circuits,

the sensor pixel circuits are spaced apart at a first pitch distance in a first direction, and

each pixel input electrode has a nominal width in the first direction greater than about 70% of the first pitch distance and less than the first pitch distance.

6. The display module of claim 1, further comprising a piezoelectric layer that overlays the array of sensor pixel circuits.

7. The display module of claim 1, wherein the sensor pixel circuits are arrayed with a density of approximately 500 sensor pixel circuits per inch or higher.

8. The display module of claim 1, further comprising:

a plurality of display data traces that are substantially parallel to one another and spaced apart by a first pitch distance within the area of the TFT backplane occupied by the array of display pixel circuits; and

a display fanout, wherein;

the display data traces enter the display fanout spaced apart by the first pitch distance and exit the display fanout spaced apart by a second pitch distance less than the first pitch distance, and

the display fanout is located substantially between the array of sensor pixel circuits and the array of display pixel circuits.

9. The display module of claim 8, further comprising:

a plurality of sensor data traces that are substantially parallel to one another and spaced apart by a third pitch distance within the area of the TFT backplane occupied by the array of sensor pixel circuits; and

a sensor fanout, wherein the sensor data traces enter the sensor fanout spaced apart by the third pitch distance and exit the sensor fanout spaced apart by a fourth pitch distance less than the third pitch distance.

10. The display module of claim 9, further comprising:

a display driver chip located on the TFT backplane; and

a sensor driver chip located on the TFT backplane, wherein;

the display driver chip is electrically connected to the display data traces exiting the display fanout,

the sensor driver chip is electrically connected to the sensor data traces exiting the sensor fanout, and

the sensor driver chip and the display driver chip are separate chips.

11. The display module of claim 9, further comprising:

a combined display and sensor driver chip located on the TFT backplane, wherein;

the combined display and sensor driver chip is electrically connected to the display data traces exiting the display fanout and the sensor data traces exiting the sensor fanout, and

the combined display and sensor driver chip is a single, integrated chip.

12. A display module comprising:

a cover glass sized larger than an active display area of the display module;

a thin-film transistor (TFT) backplane with a first side and an opposing second side, wherein the TFT backplane has;

an array of display pixel circuits located on the first side, wherein the display module has an active display area defined by the maximum extents of the array of display pixel circuits, and

an array of sensor pixel circuits located on the first side, each sensor pixel circuit configured to form part of a piezoelectric ultrasonic fingerprint sensor circuit for a piezoelectric ultrasonic fingerprint sensor, wherein the array of sensor pixel circuits is located outside of the active display area;

one or more display components positioned between the cover glass and the TFT backplane, the one or more display components configured to, in conjunction with the array of display pixel circuits, provide display functionality for the display module;

the piezoelectric ultrasonic fingerprint sensor, wherein;

at least part of the piezoelectric ultrasonic fingerprint sensor is located between the TFT backplane and the cover glass, and

the array of sensor pixel circuits forms part of the piezoelectric ultrasonic fingerprint sensor; and

one or more layers of material interposed between the piezoelectric ultrasonic fingerprint sensor and the cover glass, wherein the one or more layers of material is free of gaps between the piezoelectric ultrasonic sensor and the cover glass.

13. The display module of claim 12, wherein:

the ultrasonic sensor system includes an ultrasonic transmitter and an ultrasonic receiver in a stacked arrangement, and

the distance between the ultrasonic transmitter and the cover glass and the distance between the ultrasonic receiver and the cover glass are both substantially free of gaps.

14. The display module of claim 13, wherein:

the ultrasonic transmitter includes a piezoelectric ultrasonic transmitter layer interposed between a first transmitter electrode and a second transmitter electrode, and the ultrasonic receiver includes a piezoelectric ultrasonic receiver layer interposed between the array of sensor pixel circuits and a receiver bias electrode.

15. The display module of claim 14, wherein the ultrasonic receiver is interposed between the TFT backplane and the cover glass.

16. The display module of claim 15, further comprising

the one or more layers of material include one or more spacers arranged in a stacked configuration with the ultrasonic receiver, wherein:

the one or more display components positioned between the cover glass and the TFT backplane has a display stack thickness that defines an offset between the cover glass and the TFT backplane,

the ultrasonic receiver, inclusive of the receiver bias electrode, has an ultrasonic receiver thickness that is less than the display stack thickness, and

the stacked configuration of the one or more spacers and the ultrasonic receiver, inclusive of the receiver bias electrode and any adhesive or bonding layers between the ultrasonic receiver and the one or more spacers, has a first stack thickness that is substantially equal to the display stack thickness.

17. The display module of claim 14, further comprising a conductive touch layer formed on the cover glass, wherein the receiver bias electrode is provided by a portion of the conductive touch layer.

18. The display module of claim 17, wherein the conductive touch layer around the array of sensor pixel circuits is electrically reinforced with an electrically-reinforcing material and the conductive touch layer within the array of sensor pixel circuits is substantially free of the electrically-reinforcing material.

19. The display module of claim 18, wherein the electrically-reinforcing material is silver ink.

20. A display module comprising:

a thin-film transistor (TFT) backplane including;

a substrate with a first side and an opposing second side;

an array of display pixel circuits located on the first side, each display pixel circuit configured to cause a display pixel of a display device associated with the TFT backplane to change light-emitting, light-transmitting, or light-reflecting states, wherein the display module has an active display area defined by the maximum extents of the array of display pixel circuits; and

a piezoelectric ultrasonic sensor pixel circuit located on the first side, the sensor pixel circuit configured to form part of a piezoelectric ultrasonic sensor circuit configured to read a charge provided to the piezoelectric ultrasonic sensor circuit, wherein the sensor pixel circuit is located outside of the active display area;

one or more display components positioned between the cover glass and the TFT backplane, the one or more display components configured to, in conjunction with the array of display pixel circuits, provide display functionality for the display module; and

a piezoelectric ultrasonic sensor, wherein;

at least part of the piezoelectric ultrasonic sensor is located between the TFT backplane and the cover glass,

the piezoelectric ultrasonic sensor pixel circuit forms part of the piezoelectric ultrasonic sensor, and

the piezoelectric ultrasonic sensor includes one or more layers of material such that a surface of the piezoelectric ultrasonic sensor furthest from the TFT backplane is at the same distance from the TFT backplane as a surface of the one or more display components furthest from the TFT backplane.

21. The display module of claim 20, wherein the piezoelectric ultrasonic sensor is configured to be a button control.

22. The display module of claim 20, further comprising one or more additional piezoelectric ultrasonic sensor pixel circuits that form a further part of the piezoelectric ultrasonic sensor.

23. The display module of claim 22, wherein the piezoelectric ultrasonic sensor pixel circuit and the one or more additional piezoelectric ultrasonic sensor pixel circuits are configured to provide a slider control.

24. The display module of claim 20, further comprising:

an array of second piezoelectric ultrasonic sensor pixel circuits located on the first side, each second piezoelectric ultrasonic sensor pixel circuit configured to form part of a second piezoelectric ultrasonic sensor circuit configured to read a charge provided to the second piezoelectric ultrasonic sensor circuit from an array location, wherein;

the array of display pixel circuits and the array of second piezoelectric ultrasonic sensor pixel circuits occupy non-overlapping areas of the TFT backplane.