Multi-function enhacement film

• US 20070115407A1
• Filed: 11/18/2005
• Published: 05/24/2007
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Jones, Clinton, Richard, James
• Granted Patent: US 7,777,832 B2
• Time in Patent Office: Days
• US Class Current: 349/112
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members

Abstract

A light management unit is described for attachment to a display module, especially suited for an LCD TV or LCD monitor. The light management unit includes a directionally recycling layer including a structured side and a planar side where the structured side includes prism structures. The light management unit also includes a reflective polarizer positioned on the planar side of the directionally recycling layer. The light management unit also includes a diffusion structure incorporated into either the directionally recycling layer or between the directional recycling layer and the reflective polarizer. The diffusion structure causes a level of diffusion that is sufficient to prevent the appearance of colored bands when a viewer positioned along a line of sight that is perpendicular to the direction of the prism structures views the light management unit, illuminated from below, at an oblique angle from a vertical axis.

Claims

1. A light management unit for attachment to a display module, including:

a) a directionally recycling layer including a structured side and a planar side where the structured side includes prism structures;

b) a reflective polarizer adapted to transmit light having a first polarization orientation and to reflect light having a different polarization orientation, wherein the reflective polarizer is positioned on the planar side of the directionally recycling layer;

c) a diffusion structure incorporated into the directionally recycling layer or the interfaces between the directional recycling layer and the reflective polarizer, where the diffusion structure diffuses light that passes through the diffusion structure,

(i) wherein the diffusion caused by the diffusion structure is sufficient to prevent the appearance of colored bands when a viewer positioned along a line of sight perpendicular to the prism structures views the light management unit at an oblique angle from a vertical axis.

2. The unit of claim 1, wherein the prism structures have an angle of 90 degrees.

3. The unit of claim 1, wherein the diffusion structure includes a roughened surface on the structured side of the directionally recycling layer.

4. The unit of claim 1, wherein the directionally recycling layer comprises:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structured side;

wherein the diffusion structure includes light diffusing features scattered throughout an interior of the prism structure layer.

5. The unit of claim 4, wherein the light diffusing features are selected from the group of beads of a different refractive index than a resin forming the prism structures, micro-voids of air, and light scattering particles.

6. The unit of claim 1, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structure side;

wherein the diffusion structure includes light diffusing features scattered throughout an interior of the prism substrate layer.

7. The unit of claim 6, wherein the light diffusing features are selected from the group of beads of a different refractive index than a resin forming the prism substrate, micro-voids of air, and light scattering particles.

8. The unit of claim 1, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structure side;

wherein the diffusion structure includes;

a difference in indices of refraction between the prism substrate layer and the prism structure layer; and

a roughened surface on the prism substrate layer that is adjacent to the prism structure layer.

9. The unit of claim 1, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structure side;

wherein the light management unit further comprises an adhesive layer between the prism substrate layer and the reflective polarizer,

wherein the diffusion structure includes;

a difference in indices of refraction between the prism substrate layer and the adhesive layer; and

a roughened surface on the side of the prism substrate layer that is adjacent to the adhesive layer.

10. The unit of claim 1, further comprising:

(a) an adhesive layer between the directionally recycling layer and the reflective polarizer, wherein the diffusion structure includes light scattering particles in the adhesive layer.

11. The unit of claim 1, wherein the diffusion structure comprises:

(a) a reflective polarizer skin layer with diffuse features, positioned between the directionally recycling layer and the reflective polarizer.

12. A display system, comprising:

a) a backlight;

b) a liquid crystal display (LCD) panel comprising upper and lower plates and a liquid crystal layer disposed between the upper and lower plates; and

c) a light management unit disposed between the backlight and the LCD panel, wherein the light management unit includes;

(i) a directionally recycling layer including a structured side and a planar side where the structured side includes prism structures;

(ii) a reflective polarizer adapted to transmit light having a first polarization orientation and to reflect light having a different polarization orientation, wherein the reflective polarizer is positioned on the planar side of the directionally recycling layer;

(iii) a diffusion structure incorporated into the directionally recycling layer or the interfaces between the directional recycling layer and the reflective polarizer,

wherein the diffusion caused by the diffusion structure is sufficient to prevent the appearance of colored bands when a viewer positioned to be parallel to the direction of the prism structures views light management unit at an oblique angle from a vertical axis.

13. The system of claim 12, wherein the prism structures have an angle of about 90 degrees.

14. The system of claim 12, wherein the diffusion structure includes a roughened surface on the structured side of the directionally recycling layer.

15. The system of claim 12, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structured side;

wherein the diffusion structure includes light diffusing features scattered throughout an interior of the prism structure layer.

16. The system of claim 15, wherein the light diffusing features are selected from the group of beads of a different refractive index than a resin forming the prism structures, micro-voids of air, and light scattering particles.

17. The system of claim 12, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structure side;

wherein the diffusion structure includes light diffusing features scattered throughout an interior of the prism substrate layer.

18. The system of claim 17, wherein the light diffusing features are selected from the group of beads of a different refractive index than a resin forming the prism substrate, micro-voids of air, and light scattering particles.

19. The system of claim 12, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structure side;

wherein the diffusion structure includes;

a difference in indices of refraction between the prism substrate layer and the prism structure layer; and

a roughened surface on the prism substrate layer that is adjacent to the prism structure layer.

20. The system of claim 12, wherein the directionally recycling layer includes:

a prism substrate layer that includes the planar side; and

a prism structure layer that includes the structure side;

wherein the light management unit further comprises an adhesive layer between the prism substrate layer and the reflective polarizer,

wherein the diffusion structure includes;

a difference in indices of refraction between the prism substrate layer and the adhesive layer; and

a roughened surface on the side of the prism substrate layer that is opposite from the prism structure layer.

21. The system of claim 12, further comprising:

(a) an adhesive layer between the directionally recycling layer and the reflective polarizer, wherein the diffusion structure includes light scattering particles in the adhesive layer.

22. The system of claim 12, wherein the diffusion structure comprises:

(a) a reflective polarizer skin layer with diffuse features, positioned between the reflective polarizer and the prism layer.