Devices for use in non-emissive displays

• US 7,573,550 B2
• Filed: 05/20/2004
• Issued: 08/11/2009
• Est. Priority Date: 05/20/2003
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware, Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Brilliant Film, LLC
• Inventors: Laurence, Andrew P., Wojciechowski, Timothy J., Lubart, Neil D.
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): Chien; Lucy P
• Application Number:
  US10/849,984
• Publication Number:
  US 20050018103A1
• Time in Patent Office: 1,909 Days
• Field of Search: 349/64, 349/62, 349/118
• US Class Current: 349/113
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A liquid crystal module comprising a liquid crystal layer containing a plurality of pixels therein, a waveguide layer, and a reflective layer provided between the liquid crystal layer and the waveguide layer, the reflective layer includes a plurality of reflective areas and a plurality of apertures to permit light to pass therethrough. The waveguide layer can include a transparent material having first and second surfaces and a plurality of spaced-apart waveguide structures defining apertures therebetween disposed within the transparent material. The waveguide structures can be configured to guide light, entering the first surface of the transparent material, through the film and permit such light to exit the second surface of the transparent material.

Claims

1. A liquid crystal module comprising:

a liquid crystal layer containing a plurality of pixels therein;

a waveguide layer including;

a transparent material having first and second surfaces, the transparent material having a first index of refraction; and

a plurality of spaced-apart waveguide structures defining apertures therebetween, the waveguide structures being disposed within the transparent film and having a second index of refraction different than the first index of refraction of the transparent material, the waveguide structures being configured to guide light, entering the first surface of the transparent material, through the film and permit such light to exit the second surface of the transparent material; and

a reflective layer provided between the liquid crystal layer and the waveguide layer, the reflective layer includes a plurality of reflective areas and a plurality of apertures to permit light to pass therethrough;

wherein the liquid crystal layer, the reflective layer, and the waveguide layer are all aligned with each other such that;

each pixel in the liquid crystal layer is substantially aligned with two reflective areas separated by one of the apertures in the reflective layer, and

the apertures between each waveguide structure are substantially aligned with the apertures in the reflective layer.

2. The liquid crystal module of claim 1, wherein each waveguide structure has a base associated with the second surface of the transparent material, and each reflective area is substantially aligned with the base of one of the waveguide structures.

3. The liquid crystal module of claim 1, wherein the waveguide structures are defined by voids in the transparent material.

4. The liquid crystal module of claim 3, wherein the voids are filled with air, metal, or polymer.

5. The liquid crystal module of claim 1, wherein the plurality of waveguide structures each include a triangular shaped cross-section having a base adjacent the second surface of the transparent material, and a pair of sidewalls that converge to an apex.

6. The liquid crystal module of claim 5, wherein the angle of each sidewall relative to the base of the triangular shaped waveguide structure is between about 76 degrees and less than 90 degrees.

7. The liquid crystal module of claim 5, wherein each of the plurality of waveguide structures has an aspect ratio of between about 2 and about 22.

8. The liquid crystal module of claim 1, further comprising a backlight assembly provided below the waveguide layer.

9. The liquid crystal module of claim 1, wherein:

light arriving from a first direction facing the first surface of the transparent material is guided by the waveguide structures and transmitted through the transparent material thereby exiting the second surface of the transparent material; and

light arriving from a second direction, opposite the first direction, is reflected by the reflecting areas of the reflecting layer back towards the second direction,

wherein the sum of the percentage of light being reflected back towards the second direction relative to the light arriving from the second direction, and the percentage of light being transmitted relative to the amount of light arriving from the first direction, is greater than 100 percent.

10. A device having transmissive and reflective properties for use in a non-emissive display having a backlight, the device comprising:

a transparent substrate including first and second surfaces, the transparent substrate having;

means for reflecting light arriving from a first direction back towards the first direction having a plurality of reflective regions, and

means for transmitting light arriving from a second direction, opposite the first direction,

wherein the sum of the percentage of light being reflected back towards the first direction relative to the amount of light arriving from the first direction, and the percentage of light being transmitted through the transparent substrate relative to the amount of light arriving from the second direction, is greater than 100 percent when measured from a reference point facing the first surface, and

a light modification layer disposed on the first surface of the transparent substrate, said light modification layer having a polarizing layer configured to polarize reflected light and transmitted light orthogonal to each other, said polarizing layer comprising;

a plurality of reflecting linear polarizing regions, each reflecting linear polarizing region being substantially aligned with each reflective region of the light reflecting means, and

a plurality of transmissive linear polarizing regions, each transmissive linear polarizing region being substantially aligned with apertures between each reflective region of the light reflecting means.

11. The device of claim 10, wherein the light reflecting means includes a plurality of spaced-apart reflective regions adjacent the first surface of the transparent substrate.

12. The device of claim 11, wherein the light transmitting means includes a plurality of waveguide structures, each waveguide structure being associated with each reflective region, each waveguide structure having an index of refraction different than the index of refraction of the transparent substrate.

13. The device of claim 12, wherein the light transmitting means is configured to guide light entering the second surface of the transparent substrate through the transparent substrate so that such light exits the first surface of the transparent substrate.

14. The device of claim 12, wherein the waveguide structure includes a base and converging sidewalls, the base being associated with each reflective region.

15. The device of claim 10, wherein the reflecting and transmissive linear polarizing regions comprise optic axes that are orthogonal to each other.