Viewing angle switchable device and viewing angle switchable display module

• US 10,802,306 B2
• Filed: 12/21/2018
• Issued: 10/13/2020
• Est. Priority Date: 12/26/2017
• Status: Active Grant

• Current Assignee: Coretronic Corporation
• Original Assignee: Coretronic Corporation
• Inventors: Chen, Ping-Yeng, Fang, Chong-Yang, Lin, Yang-Ching, Yu, Jen-Wei
• Primary Examiner(s): Nguyen, Thanh Nhan P
• Application Number:
  US16/228,777
• Publication Number:
  US 20190196236A1
• Time in Patent Office: 662 Days
• CPC Class Codes: G02F 1/1323 Arrangements for providing a switchable viewing angle
• CPC Class Codes: G02F 1/133531 characterised by the arrangement of polariser or analyser axes
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133538 with spatial distribution of the polarisation direction
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133632 with refractive index ellipsoid inclined relative to the LC-layer surface
• CPC Class Codes: G02F 1/133634 the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
• CPC Class Codes: G02F 2201/44 Arrangements combining different electro-active layers, e.g. electrochromic, liquid crystal or electroluminescent layers
• CPC Class Codes: H10K 59/50 OLEDs integrated with light modulating elements, e.g. with electrochromic elements, photochromic elements or liquid crystal elements
• CPC Class Codes: H10K 59/877 comprising scattering means
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/8793 Arrangements for polarized light emission H10K59/8791 takes precedence

Abstract

A viewing angle switchable device including an absorptive polarizer, a reflective polarizer and an electrically controlled viewing angle switching element is provided. A transmission axis of the reflective polarizer is parallel to a transmission axis of the absorptive polarizer. The electrically controlled viewing angle switching element is disposed between the absorptive polarizer and the reflective polarizer and includes two transparent substrates, two transparent conductive layers and a liquid crystal layer including a plurality of liquid crystal molecules. When there is a potential difference between the two transparent conductive layers, an orthogonal projection of an optical axis of each of the plurality of liquid crystal molecules on the absorptive polarizer is parallel to or perpendicular to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer. A viewing angle switchable display module including the viewing angle switchable device is also provided.

Claims

1. A viewing angle switchable device, comprising:

an absorptive polarizer;

a reflective polarizer, disposed at a side of the absorptive polarizer, wherein a transmission axis of the reflective polarizer is parallel to a transmission axis of the absorptive polarizer;

an electrically controlled viewing angle switching element, disposed between the absorptive polarizer and the reflective polarizer and comprising two conductive layers and a liquid crystal layer disposed between the two conductive layers; and

a compensation film, disposed between the absorptive polarizer and the reflective polarizer and overlapped with the electrically controlled viewing angle switching element,

wherein the liquid crystal layer comprises a plurality of liquid crystal molecules, and when there is a potential difference between the two conductive layers, an orthogonal projection of an optical axis of each of the plurality of liquid crystal molecules on the absorptive polarizer is parallel to or perpendicular to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

2. The viewing angle switchable device as claimed in claim 1, wherein the compensation film is an A-type plate, an O-type plate, a C-type plate or a composite plate constructed by at least two of the above three types of plates.

3. The viewing angle switchable device as claimed in claim 1, further comprising:

a compensation element, disposed on a surface of the reflective polarizer away from the electrically controlled viewing angle switching element or disposed on a surface of the absorptive polarizer away from the electrically controlled viewing angle switching element,

wherein the compensation element comprises a compensation film and an absorptive polarizer, wherein a transmission axis of the absorptive polarizer of the compensation element is parallel to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer, and

wherein the absorptive polarizer of the compensation element is disposed on a surface of the compensation film of the compensation element away from the electrically controlled viewing angle switching element.

4. The viewing angle switchable device as claimed in claim 3, wherein the compensation film of the compensation element is an A-type plate, an O-type plate, a C-type plate or a composite plate constructed by at least two of the above three types of plates.

5. The viewing angle switchable device as claimed in claim 1, wherein the reflective polarizer has at least one opening, the at least one opening is configured with another absorptive polarizer, and a transmission axis of the another absorptive polarizer is parallel to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

6. The viewing angle switchable device as claimed in claim 1,

wherein the reflective polarizer has at least one opening, and the viewing angle switchable device further comprises another absorptive polarizer, and

wherein the reflective polarizer is disposed between the another absorptive polarizer and the electrically controlled viewing angle switching element, and a transmission axis of the another absorptive polarizer is parallel to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

7. The viewing angle switchable device as claimed in claim 1, wherein the electrically controlled viewing angle switching element further comprises two substrates, and the two conductive layers are disposed between the two substrates.

8. The viewing angle switchable device as claimed in claim 7, wherein the two substrates are transparent.

9. The viewing angle switchable device as claimed in claim 1, wherein at least one of the two conductive layers is transparent.

10. A viewing angle switchable display module, comprising:

a display panel; and

a viewing angle switchable device, disposed on a display surface of the display panel and comprising;

an absorptive polarizer;

a reflective polarizer, disposed at a side of the absorptive polarizer, wherein a transmission axis of the reflective polarizer is parallel to a transmission axis of the absorptive polarizer;

an electrically controlled viewing angle switching element, disposed between the absorptive polarizer and the reflective polarizer and comprising two conductive layers and a liquid crystal layer disposed between the two conductive layers; and

a compensation film, disposed between the absorptive polarizer and the reflective polarizer and overlapped with the electrically controlled viewing angle switching element,

wherein the liquid crystal layer comprises a plurality of liquid crystal molecules, and when there is a potential difference between the two conductive layers, an orthogonal projection of an optical axis of each of the plurality of liquid crystal molecules on the absorptive polarizer is parallel to or perpendicular to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

11. The viewing angle switchable display module as claimed in claim 10, wherein the compensation film is an A-type plate, an O-type plate, a C-type plate or a composite plate constructed by at least two of the above three types of plates.

12. The viewing angle switchable display module as claimed in claim 10, further comprising:

a compensation element, overlapped with the display panel and the viewing angle switchable device,

wherein the compensation element comprises a compensation film and an absorptive polarizer, wherein a transmission axis of the absorptive polarizer of the compensation element is parallel to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

13. The viewing angle switchable display module as claimed in claim 12, wherein the compensation film of the compensation element is an A-type plate, an O-type plate, a C-type plate or a composite plate constructed by at least two of the above three types of plates.

14. The viewing angle switchable display module as claimed in claim 10, wherein the display panel is an organic light-emitting display panel.

15. The viewing angle switchable display module as claimed in claim 10, wherein the display panel is a liquid crystal display panel, and the viewing angle switchable display module further comprises a collimation backlight module and an electrically controlled optical diffuser disposed on a light emitting surface of the collimation backlight module.

16. The viewing angle switchable display module as claimed in claim 10, wherein the display panel is a liquid crystal display panel, and the viewing angle switchable display module further comprises:

a backlight module, wherein the backlight module comprises at least one diffuser and two prism sheets.

17. The viewing angle switchable display module as claimed in claim 10, wherein the reflective polarizer has at least one opening, the at least one opening is configured with another absorptive polarizer, and a transmission axis of the another absorptive polarizer is parallel to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

18. The viewing angle switchable display module as claimed in claim 10,

wherein the reflective polarizer has at least one opening, and the viewing angle switchable device further comprises another absorptive polarizer, and

wherein the reflective polarizer is disposed between the another absorptive polarizer and the electrically controlled viewing angle switching element, and a transmission axis of the another absorptive polarizer is parallel to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.

19. The viewing angle switchable display module as claimed in claim 10, wherein the electrically controlled viewing angle switching element further comprises two substrates, and the two conductive layers are disposed between the two substrates.

20. The viewing angle switchable display module as claimed in claim 19, wherein the two substrates are transparent.

21. The viewing angle switchable display module as claimed in claim 10, wherein at least one of the two conductive layers is transparent.