Optical system with high contrast

• US 8,405,895 B2
• Filed: 11/10/2008
• Issued: 03/26/2013
• Est. Priority Date: 11/26/2007
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hitschmann, Guido, Schenke, Kay-Uwe
• Primary Examiner(s): Jones, James
• Application Number:
  US12/744,457
• Publication Number:
  US 20100328749A1
• Time in Patent Office: 1,597 Days
• Field of Search: 359/238
• US Class Current: 359/238
• CPC Class Codes: B60K 35/00 Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02F 2201/38 Anti-reflection arrangements

Abstract

An optical system is disclosed that includes a housing that has an interior, a reflective interior surface, and a first opening. The optical system further includes a spatial light modulator that is disposed proximate the first opening and a light source that is disposed within the interior of the housing. The spatial light modulator modulates the light that is emitted by the light source to form image rays. The optical system further includes a first light redirecting film that is disposed proximate the first opening between the spatial light modulator and the light source. The first light redirecting film recycles at least a portion of the light that is emitted by the light source. The optical system further includes an optically absorptive film that is disposed proximate the first opening between the spatial light modulator and the viewing position. The optically absorptive film receives the image rays from the spatial light modulator and displays the received image rays to the viewing position.

Claims

1. An optical system for displaying an image to a viewing position, comprising:

a housing comprising an interior, a reflective interior surface, and a first opening;

a spatial light modulator disposed proximate the first opening;

a light source disposed within the interior of the housing, the spatial light modulator modulating light emitted by the light source to form image rays;

a first light redirecting film disposed proximate the first opening between the spatial light modulator and the light source and recycling at least a portion of light emitted by the light source; and

an optically absorptive film disposed proximate the first opening between the spatial light modulator and the viewing position, the optically absorptive film receiving the image rays from the spatial light modulator and displaying the received image rays to the viewing position.

2. The optical system of claim 1, wherein the reflective interior surface of the house is diffusively reflective.

3. The optical system of claim 1, wherein the housing further comprises a black exterior.

4. The optical system of claim 1, wherein the reflective interior surface includes a reflective coating.

5. The optical system of claim 1, wherein the reflective interior surface includes a reflective film laminated to the interior surface.

6. The optical system of claim 1, wherein the light source comprises a plurality of light emitting elements.

7. The optical system of claim 1, wherein the light source comprises an LED.

8. The optical system of claim 1, wherein the first light redirecting film comprises and array of linear prisms.

9. The optical system of claim 1 further comprising a second light redirecting film disposed proximate the first opening between the first light redirecting film and the spatial light modulator and recycling at least a portion of light emitted by the light source.

10. The optical system of claim 1, wherein the optically absorptive film comprises:

an optically absorptive layer; and

a plurality of optically transparent beads partially embedded in the optically absorptive layer, the embedded portion of the beads facing the viewing position.

11. The optical system of claim 1, wherein the spatial light modulator forms the image rays within an emitted cone having an emitted angle, and wherein the optically absorptive film has an acceptance angle that is at least as large as the emitted angle.

12. The optical system of claim 1 further comprising a cover attached to a viewing side of the optically absorptive film facing the viewing position.

13. The optical system of claim 12, wherein the cover and the optically absorptive film are releasably attached to the housing.