Electroluminescent display device integrated with fingerprint sensor

• US 10,579,854 B2
• Filed: 11/26/2017
• Issued: 03/03/2020
• Est. Priority Date: 11/28/2016
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Choo, Kyoseop, Kim, Hongchul, Kang, Hoon, Lee, Buyeol, Ryu, Seungman
• Primary Examiner(s): Azongha, Sardis F
• Application Number:
  US15/822,170
• Publication Number:
  US 20180150671A1
• Time in Patent Office: 828 Days
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• 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: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens
• CPC Class Codes: H10K 59/65 OLEDs integrated with inorganic image sensors

Abstract

An electroluminescent display device integrated with a fingerprint sensor comprises: a display panel comprising a plurality of display pixels; a transparent substrate bonded to the top of the display panel; and an image sensor bonded to the bottom of the display panel, wherein each of the display pixels in at least some part of the pixel array on the display panel comprises a light transmission area, the image sensor comprises a plurality of photosensors, one or more of the photosensors are exposed within the light transmission area, and the resolution of the image sensor is higher than or equal to the resolution of the display panel.

Claims

1. An electroluminescent display device integrated with a fingerprint sensor, comprising:

a display panel comprising a plurality of display pixels, each display pixel disposed in at least some of pixel arrays comprising a light transmission area;

a transparent substrate attached to a top surface of the display panel;

a light source disposed under an edge of the transparent substrate;

a light-entering element and a light-exiting element disposed between the light source and the transparent substrate, wherein the light-entering element and the light-exiting element are formed as a single film and are adjacent to each other; and

an image sensor attached to a bottom surface of the display panel and comprising a plurality of photosensors,

wherein, at least one photosensor among the plurality of the photosensors is exposed within the light transmission area, and the image sensor has a resolution higher than or equal to a resolution of the display panel.

2. The electroluminescent display device of claim 1, wherein the light-entering element refracts light from the light source at an angle of total reflection within the transparent substrate;

and

the light-exiting element refracts part of light traveling within the transparent substrate so that the part of the light traveling within the transparent substrate travels towards the display panel through an underside of the transparent substrate.

3. The electroluminescent display device of claim 1, wherein at least some of the display pixels emit light in a sensor mode, and the emitted light from the display pixels is reflected from a fingerprint on the transparent substrate and travels towards the image sensor through the light transmission area.

4. The electroluminescent display device of claim 1, further comprising:

one or more light source attached to the bottom of the display panel; and

a light-entering element disposed between the light source and the transparent substrate and refracting light from the light source at an angle of total reflection within the transparent substrate.

5. The electroluminescent display device of claim 1, further comprising a light focusing element disposed between the display panel and the image sensor and focusing light traveling towards the image sensor.

6. The electroluminescent display device of claim 1, further comprising a low refractive index layer disposed between the light-exiting element and the display panel and having a refractive index lower than the light-exiting element.

7. The electroluminescent display device of claim 1, wherein the light-entering element and the light-exiting element include an optical element having a holographic pattern.

8. An electroluminescent display device integrated with a fingerprint sensor, comprising:

a display panel comprising a plurality of display pixels, each display pixel disposed in at least some of pixel arrays comprising a light transmission area;

a transparent substrate attached to a top surface of the display panel;

a light source disposed under an edge of the transparent substrate;

a light-entering element and a light-exiting element disposed between the light source and the transparent substrate, wherein the light-entering element and the light-exiting element are formed as a single film and are adjacent to each other; and

an image sensor attached to a bottom surface of the display panel and comprising at least one photosensor exposed within the light transmission area, wherein at least some of the display pixels are driven as photosensors in a sensor mode, or photosensors are embedded in the display panel, and the image sensor has a resolution higher than or equal to a resolution of the display panel.

9. The electroluminescent display device of claim 8, wherein, in a sensor mode, organic light-emitting diodes of at least some of the display pixels operate as photosensors by applying a reverse bias to the organic light-emitting diodes, and in a display mode, the organic light-emitting diodes of at least some of the display pixels having the organic light-emitting diodes display pixel data of an input image by applying a forward bias to the organic light-emitting diodes.

10. The electroluminescent display device of claim 9, wherein the display pixels where the reverse bias is applied sense a fingerprint pattern, and the image sensor senses a finger vein pattern.

11. The electroluminescent display device of claim 8, further comprising a light focusing element disposed between the display panel and the image sensor and focusing light traveling towards the image sensor.

12. An electroluminescent display device integrated with a fingerprint sensor, comprising:

a display panel comprising a plurality of display pixels, each display pixel disposed in at least some of pixel arrays comprising a light transmission area and sensing a fingerprint pattern;

a transparent substrate attached to a top surface of the display panel;

a light source disposed under an edge of the transparent substrate;

a light-entering element and a light-exiting element disposed between the light source and the transparent substrate, wherein the light-entering element and the light-exiting element are formed as a single film and are adjacent to each other; and

an image sensor attached to a bottom surface of the display panel, comprising a plurality of photosensors and sensing a finger vein pattern,

wherein at least one photosensor among the plurality of the photosensors is exposed within the light transmission area, and the image sensor has a resolution at least equal to a resolution of the display panel.

13. The electroluminescent display device of claim 12, wherein the display pixels are applied by a reverse bias when the fingerprint pattern is sensed.

14. The electroluminescent display device of claim 12, further comprising a light focusing element disposed between the display panel and the image sensor and focusing light traveling towards the image sensor.

15. The electroluminescent display device of claim 12, wherein the light-entering element refracts light from the light source at an angle of total reflection within the transparent substrate;

and

the light-exiting element refracts part of light traveling within the transparent substrate so that the part of the light traveling within the transparent substrate travels towards the display panel through an underside of the transparent substrate.

16. The electroluminescent display device of claim 12, wherein at least some of the display pixels emit light in a sensor mode, and the emitted light from the display pixels is reflected from a fingerprint on the transparent substrate and travels towards the image sensor through the light transmission area.

17. The electroluminescent display device of claim 12, further comprising:

at least one light source attached to the bottom of the display panel; and

a light-entering element disposed between the light source and the transparent substrate and refracting light from the light source at an angle of total reflection within the transparent substrate.

18. The electroluminescent display device of claim 12, wherein at least some of the display pixels have organic light-emitting diodes operating as photosensors by applying a reverse bias to the organic light-emitting diodes in a sensor mode.

19. The electroluminescent display device of claim 12, wherein at least some of the display pixels having organic light-emitting diodes display pixel data of an input image by applying a forward bias to the organic light-emitting diodes in a display mode.

20. The electroluminescent display device of claim 12, further comprising a low refractive index layer disposed between the light-exiting element and the display panel and having a refractive index lower than the light-exiting element.