Flat panel display embedding optical imaging sensor

• US 10,395,086 B2
• Filed: 05/02/2018
• Issued: 08/27/2019
• Est. Priority Date: 05/02/2017
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Guensik, Choo, Kyoseop, Ryu, Seungman
• Primary Examiner(s): Yushin, Nikolay K
• Application Number:
  US15/969,600
• Publication Number:
  US 20180322325A1
• Time in Patent Office: 482 Days
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: H10K 39/32 Organic image sensors
• CPC Class Codes: H10K 59/65 OLEDs integrated with inorganic image sensors

Abstract

The present disclosure relates to a flat panel display embedding an optical imaging sensor such as a fingerprint image sensor. The present disclosure suggests a flat panel display embedding an image sensor comprising: a display panel including a display area and a non-display area; and a directional optical unit having a length and a width corresponding to the display panel and a thickness, and attached on a top surface of the display panel, wherein the directional optical unit provides a sensing light beam to the display area, and wherein the sensing light is collimated and directionized to a predetermined direction.

Claims

1. A flat panel display embedding an image sensor comprising:

a display panel including a display area and a non-display area, the display panel having a top surface; and

a directional optical unit attached to the top surface of the display panel, the directional optical unit having a length along a length axis of the display panel, a width along a width axis of the display panel and a thickness along to a thickness axis of the display panel,

wherein the directional optical unit includes;

a cover plate having a size corresponding to the length and the width of the directional optical unit;

a light radiating film corresponding to the display area, the light radiating film positioned under the cover plate;

a light incident film positioned under the cover plate and disposed outside of the display area adjacent to a lateral side of the light radiating film;

a low refractive layer disposed under the light radiating film and the light incident film, the low refractive layer attached on the top surface of the display panel, and having a refractive index that is lower than a refractive index of the cover plate and that is lower than a refractive index of the light radiating film; and

a light source positioned under the light incident film,

wherein the directional optical unit provides a sensing light beam to the display area,

wherein the sensing light beam is collimated and directionized along a predetermined direction,

wherein the light source provides an incident light beam to an incident point on a surface of the light incident film,

wherein the light incident film has a first polarization axis along to a predetermined direction; and

wherein the light source provides an infrared light beam polarized in a second polarization axis which is parallel to the first polarization axis.

2. The device according to the claim 1, wherein the light radiating film has a third polarization axis parallel to the first polarization axis.

3. The device according to the claim 1, wherein the display panel further includes a polarization plate disposed on the top surface and having a fourth polarization axis parallel to the first polarization axis.

4. The device according to the claim 1, wherein the light incident film includes a first holographic pattern that converts the incident light beam to a propagating light having an incident angle satisfying an internal total reflection condition of the cover plate, and that transmits the propagating light beam into the cover plate;

and

wherein the light radiating film includes a second holographic pattern that converts a first portion of the propagating light beam into the sensing light beam, the sensing light beam having a reflection angle that satisfies a total reflection condition at a top surface of the cover plate and that satisfies a transmitting condition through the low refractive layer.

5. The device according to the claim 1, wherein the propagating light beam has an expanding angle on a horizontal plane including the length axis and the width axis, and the propagating light beam maintains the collimated state on a vertical plane including the length axis and the thickness axis;

wherein the incident angle is larger than an internal total reflection critical angle at a first interface between the light radiating film and the low refractive layer; and

wherein the reflection angle is larger than a total reflection critical angle at a second interface between the cover plate and an air layer, and smaller than a total reflection critical angle at the first interface between the light radiating film and the low refractive layer.