Low birefringent light redirecting film

• US 20080285255A1
• Filed: 07/11/2008
• Published: 11/20/2008
• Est. Priority Date: 07/13/2005
• Status: Abandoned Application

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: Rohm and Haas Denmark Finance A/S
• Inventors: Bourdelais, Robert P., Neerbasch, Steven J., Brickey, Cheryl J.
• Application Number:
  US12/218,103
• Publication Number:
  US 20080285255A1
• Time in Patent Office: Days
• US Class Current: 362/19
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects

Abstract

The invention relates to a polymeric optical film comprising a base provided with integral optical features on at least one side, wherein the features have two or more sides that form a ridge line, wherein the optical film has light leakage through crossed polarizers of less than 1.0%.

Claims

1-35. -35. (canceled)

36. A liquid crystal display comprising a backlight section, the backlight section comprising:

a light source for providing light to the display;

a waveguide for receiving the light;

a reflector on a back side of the waveguide for reflecting the light towards normal;

a diffuser film on the front side of the waveguide for diffusing incoming light;

a light redirecting film having a birefringence of between 1.0×

10<sup>−

5</sup> to 5.0×

10<sup>−

3</sup>;

a first polarizer crossed from a second polarizer; and

wherein the light redirecting film is provided between the first and second polarizers and the light leakage through the crossed first and second polarizers and the light redirecting film is less than 1.0%.

37. The liquid crystal display of claim 36, wherein the light leakage is between 0.05 to 0.5%.

38. The liquid crystal display of claim 36, wherein the first polarizer is a reflective polarizer.

39. The liquid crystal display of claim 36, wherein the second polarizer is an absorptive polarizer.

40. The liquid crystal display of claim 36, wherein the light redirecting film comprises a cellulose triacetate polymer.

41. The liquid crystal display of claim 36, wherein the light redirecting film comprises a cyclo-olefin.

42. A liquid crystal display comprising a backlight section, the backlight section comprising:

a light source for providing light to the display;

a polarizing waveguide for receiving the light;

a reflector on a back side of the waveguide for reflecting the light towards normal;

a light redirecting film having a birefringence of between 1.0×

10<sup>−

5</sup> to 5.0×

0-3;

an absorptive polarizer crossed from the polarizing waveguide; and

wherein the light redirecting film is provided between the polarizing waveguide and the absorptive polarizer and the light leakage through the crossed polarizing waveguide and the absorptive polarizer, and the light redirecting film is less than 1.0%.

43. A liquid crystal display comprising:

a light source for providing light to the display;

a waveguide for receiving the light;

a reflector on a back side of the waveguide for reflecting the light towards normal;

a diffuser film on the front side of the waveguide for diffusing incoming light;

a light redirecting film having a birefringence of between 1.0×

10<sup>−

5</sup> to 5.0×

10<sup>−

3</sup>;

a liquid crystal cell for transmitting polarized light;

a first absorptive polarizer crossed from a second absorptive polarizer; and

wherein the light redirecting film and the liquid crystal cell are provided between the first and second absorptive polarizers and the light leakage through the crossed first and second absorptive polarizers, and the light redirecting film and liquid crystal cell is less than 1.0%.