Liquid crystal display viewable under all lighting conditions

• US 6,909,486 B2
• Filed: 02/18/2003
• Issued: 06/21/2005
• Est. Priority Date: 02/18/2003
• Status: Active Grant

• Current Assignee: Min-Shine C. Wang, Ran-Hong Raymond Wang
• Original Assignee: Min-Shine C. Wang, Ran-Hong Raymond Wang
• Inventors: Wang, Ran-Hong Raymond, Wang, Min-Shine C.
• Primary Examiner(s): Dudek, James A.
• Application Number:
  US10/370,360
• Publication Number:
  US 20040160551A1
• Time in Patent Office: 854 Days
• Field of Search: 349/114, 349/137, 349/112
• US Class Current: 349/137
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133555 Transflectors

Abstract

A liquid crystal display (LCD) viewable under all lighting conditions without excessive power consumption is described. The LCD comprises a first dichroic polarizer, a second dichroic polarizer, an anti-reflection layer positioned in front of the first dichroic polarizer and a liquid crystal cell positioned between the first dichroic polarizer and the second dichroic polarizer. In addition, the LCD comprises a backlight assembly positioned behind the second dichroic polarizer. Finally, the LCD comprises a diffusing transflector positioned between the backlight assembly and the second dichroic polarizer. The diffusing transflector comprises a diffusing element and a transflective element.

Claims

1. A liquid crystal display comprising:

(a) a first dichroic polarizer;

(b) a second dichroic polarizer;

(c) an anti-reflection layer positioned in front of the first dichroic polarizer with reflection energy less than 1% and a surface with a haze value less than 15%, the anti-reflection layer being a high efficiency multi-layer coating;

(d) a liquid crystal cell positioned between the first dichroic polarizer and the second dichroic polarizer;

(e) a backlight assembly positioned behind the second dichroic polarizer; and

(f) a diffusing transflector positioned between the backlight assembly and the second dichroic polarizer, the diffusing transflector comprising a diffusing element and a transflective element, the diffusing element being a corrugated surface with a haze value of 10% to 85%.

2. The liquid crystal display of claim 1 wherein the anti-reflection layer is a separate glass or plastic transmissive substrate with a first side of haze less than 15% and a second side, the first side having a high efficiency multi-layer anti-reflection coating, and the second side adhered to a front side of the first dichroic polarizer.

3. The liquid crystal display of claim 1 wherein the corrugated surface is a roughened surface with a haze value of 10% to 85%.

4. The liquid crystal display of claim 3 wherein the roughened surface is a front surface of one single sheet or multiple sheets of a transmissive substrate, the transmissive substrate being glass, PEN (polyethylene naphthalate), PC (polycarbonate), or PET (polyethylene terephthalate).

5. The liquid crystal display of claim 1 wherein the corrugated surface is a deposited layer on a front surface of a transmissive substrate, the transmissive substrate being glass, PEN (polyethylene naphthalate), PC (polycarbonate), or PET (polyethylene terephthalate).

6. The liquid crystal display of claim 5 wherein dielectric material is deposited on the front surface of the transmissive substrate to form the corrugated surface, the dielectric material being TiO₂ (Titanium dioxide), Ta₂O₅ (Tantalum oxide), SiO2 (Silicon dioxide), SiN (Silicon nitride), ITO (Indium tin oxide), ZnS (Zinc sulphide), Al₂O₃ (Aluminum oxide), LaF₃ (Lanthanum fluoride), MgF₂ (Magnesium fluoride), Ge (Germanium), or Si (Silicon).

7. The liquid crystal display of claim 5 wherein a multi-layer dielectric material is deposited on the front surface of the transmissive substrate to form the corrugated surface, the multi-layer dielectric material including at least one of TiO₂ (Titanium dioxide), Ta₂O₅ (Tantalum oxide), SiO₂ (Silicon dioxide), SiN (Silicon nitride), ITO (Indium tin oxide), ZnS (Zinc sulphide), Al₂O₃ (Aluminum oxide), LaF₃ (Lanthanum fluoride), MgF₂ (Magnesium fluoride), Ge (Germanium), and Si (Silicon).

8. The liquid crystal display of claim 5 wherein particles of metal ranging in size from 10 nm to 10000 nm are deposited on the transmissive substrate to form the corrugated surface, the corrugated surface having a transmission ranging from 10% to 85%, and the metal being silver, gold, aluminum, copper, titanium, tantalum, chromium, nickel or an alloy thereof.

9. The liquid crystal display of claim 8 wherein the transmissive substrate is laminated to a rear side of the second dichroic polarizer.

10. The liquid crystal display of claim 1 wherein the corrugated surface is formed by metal particles ranging in size from 10 nm to 10000 nm deposited on a rear side of the second dichroic polarizer, the corrugated surface having a transmission ranging from 10% to 85%, and the metal being silver, gold, aluminum, copper, titanium, tantalum, chromium, nickel or an alloy thereof.

11. The liquid crystal display of claim 1 wherein the transflective element is a selective reflective polarizer, multiple sheets of selective reflective polarizers, or a diffuser laminated selective reflective polarizer, the transflective element having an extinction coefficient of 1.5 to 9 and an absorption of incident energy value less than 10%.

12. The liquid crystal display of claim 1 wherein a transmission direction of the transflective element and a transmission direction of the second dichroic polarizer form an angle of 0 degrees, between 0 and 60 degrees or between −

60 and 0 degrees for optimal transmission and reflection.

13. The liquid crystal display of claim 1 wherein the transflective element is a multi-layer dielectric material coating beam splitter with a transmission of 30% to 85%, the multi-layer dielectric material coating beam splitter being either applied directly on a rear side of the diffusing element or on a front side of a separate transmissive substrate.

14. The liquid crystal display of claim 1 wherein the backlight assembly comprises 1 to 12 lamps and multiple polymeric films having enhanced light transmission and optical performances, the lamps being edged or back-sided, and the polymeric film being brightness enhancement film and diffuser.

15. The liquid crystal display of claim 1 further comprising a quarter wave plate positioned between the liquid crystal cell and the second dichroic polarizer, the quarter wave plate generating a linear polarization from a circular polarization output of the liquid crystal cell, the linear polarization being parallel to a transmission direction of the second dichroic polarizer.

16. A liquid crystal display comprising:

(a) a first dichroic polarizer with a first transmission direction;

(b) a second dichroic polarizer with a second transmission direction, the second transmission direction forming an angle between 0 and 90 degrees relative to the first transmission direction;

(c) an anti-reflection layer positioned in front of the first dichroic polarizer with reflection energy less than 1% and a surface with a haze value less than 15%;

(d) a liquid crystal cell positioned between the first dichroic polarizer and the second dichroic polarizer;

(e) a backlight assembly positioned behind the second dichroic polarizer, the backlight assembly having 1 to 12 lamps and multiple polymeric films enhancing light transmission and optical performances, the lamps being edged or back-sided; and

(f) a diffusing transflector positioned between the backlight assembly and the second dichroic polarizer, the diffusing transflector comprising a diffusing element and a transflective element, the diffusing element having a corrugated surface with a haze value of 10% to 85%, and the transflective element being either a selective reflective polarizer with an extinction coefficient of 1.5 to 9 and an absorption of incident energy value less than 10%, or a beam splitter with a transmission value of 30% to 85%.

17. A liquid crystal display comprising:

(a) a first dichroic polarizer with a first transmission direction;

(b) a second dichroic polarizer with a second transmission direction, the second transmission direction forming an angle between 0 and 90 degrees relative to the first transmission direction;

(c) an anti-reflection layer positioned in front of the first dichroic polarizer with reflection energy less than 1% and a surface with a haze value less than 15%;

(d) a liquid crystal cell positioned between the first dichroic polarizer and the second dichroic polarizer;

(e) a backlight assembly positioned behind the second dichroic polarizer, the backlight assembly having 1 to 12 lamps and multiple polymeric films enhancing light transmission and optical performances, the lamps being edged or back-sided; and

(f) a diffusing transflector positioned between the liquid crystal cell and the second dichroic polarizer, the diffusing transflector comprising a diffusing element and a transflective element, the diffusing element having a corrugated surface with a haze value of 10% to 85%, and the transflective element being a beam splitter with a transmission value of 30% to 85%.