Selective Reflecting for Laser Projector

• US 20090002816A1
• Filed: 06/29/2007
• Published: 01/01/2009
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Bose Corporation
• Inventors: Lippey, Barret
• Granted Patent: US 7,710,645 B2
• Time in Patent Office: Days
• US Class Current: 359/443
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface

Abstract

A projection screen for selectively reflecting light from a front projector. The screen includes an etalon coating structure with a first layer of reflective material, a second layer of dielectric material, and a third layer of partially reflective semiconductor material. The projection screen produces a reflection having an asymmetric-shaped response in the visible spectrum.

Claims

1. An apparatus for selectively reflecting a beam of light from a front projector, the apparatus comprising:

a projection screen that includes an etalon coating structure comprising;

a first layer comprising a generally reflective material;

a second layer positioned such that it is closer to the projector than the first layer, the second layer comprising a dielectric material; and

a third layer positioned such that it is closer to the projector than the second layer, the third layer comprising a generally partially reflective semiconductor material;

wherein the projection screen produces a reflection having an asymmetric-shaped spectral response in the visible spectrum.

2. An apparatus in accordance with claim 1, wherein the reflection comprises at least two peaks in the visible spectrum.

3. An apparatus in accordance with claim 2, wherein at least one of the peaks has a faster roll-off on the shorter wavelength side of the peak than on the longer wavelength side of the peak.

4. An apparatus in accordance with claim 1, wherein the third layer has an index of refraction between 2 and 6.

5. An apparatus in accordance with claim 1, wherein the third layer has an extinction coefficient between 0.2 and 2.

6. An apparatus in accordance with claim 1, wherein the third layer has an index of refraction between 3.5 and 5 and an extinction coefficient between 0.4 and 1.5.

7. An apparatus in accordance with claim 1, wherein the third layer comprises a mixture of Silicon and Germanium.

8. An apparatus in accordance with claim 7, wherein the third layer comprises a mixture of approximately 50% Silicon and 50% Germanium.

9. An apparatus in accordance with claim 1, wherein the third layer comprises a mixture of Selenium.

10. An apparatus in accordance with claim 1, wherein the beam of light has three spectral peaks with full-width-half-maximum bandwidths of less than 20 nm.

11. An apparatus in accordance with claim 1, wherein the beam of light has three spectral peaks with full-width-half-maximum bandwidths of less than 10 nm.

12. An apparatus in accordance with claim 1, wherein the beam of light has at least one spectral peak with a full-width-half-maximum bandwidth of less than 5 nm.

13. A method of making a selective-reflecting projection screen with an asymmetric-shaped spectral response comprising:

depositing a metal layer onto a substrate;

depositing one or more dielectric layers onto the metal layer; and

depositing a semiconductor layer onto the dielectric layer.

14. A method of making a selective-reflecting projection screen with an asymmetric-shaped spectral response in accordance with claim 13 further comprising:

attaching a diffuser to the semiconductor layer.

15. An optical apparatus comprising:

a front projector;

a projection screen for selectively reflecting abeam of light from the front projector, the screen including an etalon coating structure comprising;

a first layer comprising a generally reflective material;

a second layer positioned such that it is closer to the projector than the first layer, the second layer comprising a dielectric material; and

a third layer positioned such that it is closer to the projector than the second layer, the third layer comprising a generally partially reflective semiconductor material;

wherein the projection screen produces a reflection having an asymmetric-shaped spectral response in the visible spectrum.

16. An apparatus for selectively reflecting a beam of light from a front projector, the apparatus comprising:

a projection screen that includes a coating structure comprising;

a layer of generally partially reflective semiconductor material;

wherein the projection screen produces a reflection having an asymmetric-shaped spectral response in the visible spectrum.

17. An apparatus in accordance with claim 16, wherein the reflection comprises at least two peaks in the visible spectrum.

18. An apparatus in accordance with claim 17, wherein at least one of the peaks has a faster roll-off on the shorter wavelength side of the peak than on the longer wavelength side of the peak.