Method and system for improving the contrast of LCDs using circular polarization

• US 7,274,418 B2
• Filed: 10/21/2003
• Issued: 09/25/2007
• Est. Priority Date: 10/21/2003
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Gurevich, Vladimir, Krichever, Mark
• Primary Examiner(s): QI, ZHI QIANG
• Application Number:
  US10/690,388
• Publication Number:
  US 20050083451A1
• Time in Patent Office: 1,435 Days
• Field of Search: 349/98, 349/114, 349/113, 349/117, 349/12, 349/65, 349 61- 63
• US Class Current: 349/98
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133555 Transflectors

Abstract

A display device displays images with reduced glare from external incident light. The device includes a back light located on a bottom surface of the display device to provide internal light. Moreover, the device includes an internal circular X-polarizer located external to the back light to circularly polarize internal light. In addition, the device includes a mirror to reflect external incident light. Furthermore, the device includes a liquid crystal display located external to the mirror and the internal circular X-polarizer to display images. The device also includes an external circular X-polarizer located external to the liquid crystal display to circularly polarize external incident light, and absorb reflected external incident light and polarized internal light.

Claims

1. A device for displaying images comprising:

a back light within the device for generating light and transmitting light from within the device toward an external surface thereof;

a first circular X-polarizer having a first side adjacent to a first side of the back light;

a liquid crystal display set to quarter-wave retardation having a first side adjacent to a second side of the first circular X-polarizer;

a mirror having a first side adjacent to the first side of the liquid crystal display; and

a second circular X-polarizer having a first side adjacent to a second side of the liquid crystal display.

2. The device for display images as recited in claim 1, further comprising a touch pad interposed between the liquid crystal display and the second circular X-polarizer.

3. The device for displaying images as recited in claim 1, wherein the device is a transflective display.

4. The device for displaying images as recited in claim 1, wherein the device is a reflective display.

5. The device for displaying images as recited in claim 4, wherein the reflective display includes a front light.

6. The device for displaying images as recited in claim 1, wherein the first circular X-polarizer includes a linear X-polarizer on an outer surface thereof and a quarter-wave plate on an inner surface thereof.

7. The device for displaying images as recited in claim 1, wherein the second circular X-polarizer includes a linear X-polarizer on an outer surface thereof and a quarter-wave plate on an inner surface thereof.

8. The device for displaying images as recited in claim 1, wherein the mirror is a two-way mirror.

9. A method for reducing glare in a display device comprising of:

generating and transmitting light using a back light from within the display device toward an external surface thereof;

circularly polarizing transmitted light using a first circular X-polarizer having a first side adjacent to a first side of the back light;

circularly polarizing external incident light using a second circular X-polarizer having a first side adjacent to a second side of the first circular X-polarizer;

reflecting external incident light using a mirror having a first side adjacent to the first side of the second circular X-polarizer; and

absorbing reflected external incident light and transmitted light using the second circular X-polarizer; and

generating images using a liquid crystal display set to quarter wave retardation interposed between the second circular X-polarizer and the first circular X-polarizer.

10. The method according to claim 9, wherein the display device includes a touch pad interposed between the liquid crystal display and the second circular X-polarizer.

11. The method according to claim 9, wherein the display device is a transflective display.

12. The method according to claim 9, wherein the display device is a reflective display.

13. The method according to claim 12, wherein the reflective display includes a front light.

14. The method according to claim 9, wherein the first circular X-polarizer includes a linear X-polarizer on an outer surface thereof and a quarter-wave plate on an inner surface thereof.

15. The method according to claim 9, wherein the second circular X-polarizer includes a linear X-polarizer on an outer surface thereof and a quarter-wave plate on an inner surface thereof.

16. The method according to claim 9, wherein the mirror is a two-way mirror.

17. A transflective display device to display images with reduced glare from external incident light comprising:

a back light located on a bottom surface of the display device to provide internal light;

an internal circular X-polarizer having a first side adjacent to a first side of the back light to circularly polarize internal light;

a mirror to reflect external incident light;

a liquid crystal display set to quarter wave retardation having a first side adjacent to a first side of the mirror and a second side of the internal circular X-polarizer to display images; and

an external circular X-polarizer having a first side adjacent to a second side of the liquid crystal display to circularly polarize external incident light and absorb reflected external incident light and polarized internal light.

18. A computing device, comprising:

a processor processing data; and

a display device displaying the data, the display device including a back light situated within the display device for generating light and transmitting light from within the device toward an external surface thereof, the display device further including a first circular X-polarizer situated between the back light and the external surface, a liquid crystal display set to quarter wave retardation situated between the first circular X-polarizer and the external surface, a mirror adjacent to the liquid crystal display and a second circular X-polarizer situated between the liquid crystal display and the external surface.

19. The computing device according to claim 18, wherein the computing device is a mobile computing device.

20. The computing device according to claim 19, further comprising:

a wireless communication arrangement communicating with a further computing device.

21. The computing device according to claim 18, further comprising:

a data capturing arrangement obtaining the data.

22. The computing device according to claim 21, wherein the data capturing arrangement includes at least one of a barcode reader and an RFID reader.

23. A device for displaying images comprising:

a back light within the device for generating light and transmitting light from within the device toward an external surface thereof;

a first circular X-polarizer situated between the back light and the external surface;

a liquid crystal display set to quarter wave retardation situated between the first circular X-polarizer and the external surface;

a mirror adjacent to a first portion of the liquid crystal display, the first circular X-polarizer adjacent to a second portion of the liquid crystal display; and

a second circular X-polarizer situated between the liquid crystal display and the external surface.