WIRE-GRID POLARIZERS, METHODS OF FABRICATION THEREOF AND THEIR USE IN TRANSMISSIVE DISPLAYS

• US 20070242352A1
• Filed: 04/05/2007
• Published: 10/18/2007
• Est. Priority Date: 04/13/2006
• Status: Abandoned Application

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: MacMASTER, STEVEN WILLIAM
• Application Number:
  US11/696,843
• Publication Number:
  US 20070242352A1
• Time in Patent Office: Days
• US Class Current: 359/486
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence

Abstract

Wire-grid polarizers (WGPs) and their use in transmissive displays are disclosed. The displays containing these WGPs possess high contrast and brightness characteristics in comparison to prior art displays.

Claims

1. A wire grid polarizer, comprising:

a) a transparent substrate having an optical property of transmitting electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red;

b) an array of spaced-apart, elongated elements, comprised of an electrically conductive and reflective material and disposed on the substrate, sized to interact with electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of a first polarization, and generally reflect electromagnetic waves of a second polarization;

wherein each element of the array has a surface and an opposing surface and wherein the surface possesses low reflectance.

2. The wire grid polarizer of claim 1 wherein the opposing surface possesses high reflectance.

3. The wire grid polarizer of claim 1 wherein the array interacts with electromagnetic waves having a wavelength in the visible region.

4. The wire grid polarizer of claim 1 wherein the surface of the element has a reflectance that is less than 0.35.

5. The wire grid polarizer of claim 2 wherein the opposing surface of the element has a reflectance that is greater than 0.70.

6. The wire grid polarizer of claim 2 wherein the surface of each element of the array is an outer surface and is characterized to possess low reflectance and the opposing surface of each element of the array is characterized to possess high reflectance and is an inner surface proximate to the transparent substrate.

7. The wire grid polarizer of claim 2 wherein the surface of each element of the array is an outer surface and is characterized to possess high reflectance and the opposing surface of each element of the array is characterized to possess low reflectance and is an inner surface proximate to the transparent substrate.

8. The wire grid polarizer of claim 1 wherein the material is reflective to light in the visible region of the electromagnetic spectrum.

9. A transmissive display comprising:

a) a light source having a reflective optical cavity configured to randomize direction and polarization of light reflected by the optical cavity;

b) a display module; and

c) a wire grid polarizer device placed between the light source and the display module, comprising;

1) a transparent substrate having an optical property of transmitting electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red;

2) an array of spaced-apart, elongated elements, comprised of an electrically conductive and reflective material and disposed on the substrate, sized to interact with electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of a first polarization, and generally reflect electromagnetic waves of a second polarization;

wherein each element of the array has a surface and an opposing surface and wherein the surface possesses low reflectance; and

wherein the surface is nearer the display module than the opposing surface.

10. The transmissive display of claim 9 wherein the display module does not have a rear polarizer.

11. The transmissive display of claim 9 wherein the opposing surface of the wire grid polarizer possesses high reflectance.

12. The transmissive display of claim 9 wherein the array of the wire grid polarizer interacts with electromagnetic waves having a wavelength in the visible region of the electromagnetic spectrum, and the material is reflective to light in the visible region of the electromagnetic spectrum.

13. The transmissive display of claim 9 wherein the surface of the element of the wire grid polarizer has a reflectance that is less than 0.35.

14. The transmissive display of claim 9 wherein the opposing surface of the element of the wire grid polarizer has a reflectance that is greater than 0.7.

15. The transmissive display of claim 9 wherein the surface of each element of the array of the wire grid polarizer is an outer surface and the opposing surface of each element of the array is characterized to possess high reflectance and is an inner surface proximate to the transparent substrate.

16. The transmissive display of claim 9 wherein the surface of each element of the array of the wire grid polarizer is an inner surface proximate to the transparent substrate and the opposing surface of each element of the array of the wire grid polarizer is an outer surface and is characterized to possess high reflectance.

17. The transmissive display of claim 9 further comprising:

d) a geometric structured surface material disposed between the light source and the display module, the structured surface material redirecting a portion of light incident on the structured surface material from an incidence angle to a transmission angle, the transmission angle being less than the incidence angle measured from an axis normal to the plane of the display module.

18. The transmissive display of claim 9 wherein the display does not contain an absorbing polarizer.