Backlighting transmissive displays

• US 7,293,899 B2
• Filed: 11/06/2003
• Issued: 11/13/2007
• Est. Priority Date: 09/10/2001
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Miller, Richard A., Boyd, Gary Timothy, Whitney, Leland Ray, Kotchick, Keith Michael
• Primary Examiner(s): O'Shea; Sandra
• Assistant Examiner(s): Tsidulko; Mark
• Application Number:
  US10/702,976
• Publication Number:
  US 20040136172A1
• Time in Patent Office: 1,468 Days
• Field of Search: 362/296, 362/19, 362/26, 362/600, 362/307, 362/308, 362/328, 362/329, 362/332, 362/97, 349/73, 349/77, 349/62, 349/114, 349/67, 313/110, 428/316.6
• US Class Current: 362/296.07
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A backlight assembly for use in a transmissive display system is described. The backlight assembly includes a light source that illuminates a light chamber. A transmissive display is positioned adjacent the light chamber so that light that exits the chamber illuminates the transmissive display. The backlight assembly may include one or more specular reflectors and one or more other optical elements to ensure that the light that exits the light chamber has the desired spatial uniformity, polarization, color, and/or angular distribution.

Claims

1. A backlight assembly for a transmissive display device comprising:

a light chamber divided into two chamber regions;

a light source that emits light into the light chamber;

a first conditioner disposed between the light source and the light chamber, wherein the first conditioner alters light entering the light chamber;

a reflector within the light chamber that reflects light altered by the first conditioner;

a second conditioner that alters light reflected by the reflector, wherein light exists the light chamber through the second conditioner; and

a third conditioner separating the two chamber regions of the light chamber, wherein light passes from a first chamber region of the light chamber through the third conditioner and into a second chamber region of the light chamber.

2. The backlight assembly of claim 1, wherein the third conditioner includes a diffuser film.

3. The backlight assembly of claim 1, wherein the third conditioner includes a polarizer film.

4. The backlight assembly of claim 1, further comprising a second reflector, wherein the reflectors reside respectively within the two chamber regions.

5. The backlight assembly of claim 1, wherein the light source and the second conditioner are positioned on a same side of the chamber.

6. The backlight assembly of claim 1, wherein the light source and the second conditioner are positioned on opposing sides of the chamber.

7. A transmissive display system comprising:

a light source;

a light chamber; and

a display, wherein the light source illuminates the light chamber and the light chamber illuminates the display, and wherein the light source and the display are positioned along a common side of the light chamber; and

wherein the light chamber includes a first chamber region and a second chamber region, and wherein the light source is positioned adjacent the first chamber region and the display is positioned adjacent the second chamber region.

8. The transmissive display system of claim 7, wherein the light chamber includes at least one reflector that reflects light emitted from the light source toward the display.

9. The transmissive display system of claim 7, further comprising at least one conditioner that alters light emitted from the light source.

10. A backlight assembly for a transmissive display device comprising;

a light chamber including first and second light chamber regions,

a light source that emits light into the first light chamber region,

a first conditioner that alters light that enters the first light chamber region,

a first reflector within the first light chamber region that reflects light altered by the first conditioner,

a third conditioner that alters light reflected by the first reflector, the third conditioner positioned between the first and second light chamber regions, wherein light passes from the first light chamber region of the light chamber through the third conditioner and into the second light chamber region of the light chamber,

a second reflector within the second light chamber region that reflects light altered by the third conditioner, and

a second conditioner that alters light reflected by the second reflector.

11. The backlight assembly of claim 10, wherein the first conditioner and the second conditioner are positioned on a common side of the light chamber.

12. The backlight assembly of claim 10, wherein the first conditioner and the second conditioner are positioned on opposing sides of the light chamber.

13. A backlight assembly for a transmissive display comprising:

a first light chamber,

a first light source that illuminates the first light chamber.

a second light chamber,

a second light source that illuminates the second light chamber, wherein a joining line is defined between the first and second light chambers, and

a diffuser film spanning across both the first and second light chambers such that substantially uniform illumination is achieved along the joining line of the first and second light chambers.