Optical system for image projectors

Patent metadata

Field	Value
Publication number	US-10545351-B2
Application number	US-201916363651-A
Country	US
Kind code	B2
Filing date	Mar 25, 2019
Priority date	Oct 11, 2015
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

A projector system comprising a laser light source, a collimating lens, a fly-eye lens, an integrating rod and a first modulator is disclosed. The light from a laser light source/fiber illuminates a collimator to substantially collimate the light and then is transmitted through a fly's-eye lens. The fly's-eye lens provides a desired angular/spatial light distribution for further processing to a first modulator of the projector system.

First claim

The invention claimed is:

1. A projection system, comprising:
a light source configured to emit light;
an optical collimator configured to collimate the light emitted from the light source;
an integrating rod;
exactly one focusing lens disposed between the optical collimator and the integrating rod and configured to focus the light onto an input of the integrating rod;
exactly one optical homogenizing element disposed between the optical collimator and the integrating rod, the optical homogenizing element being (a) configured to receive the light from the optical collimator and impose thereon an angular distribution before focusing of the light by the focusing lens, and (b) selected from the group consisting of a lenslet array and a fused rod bundle; and
a first modulator configured to receive the light from the integrating rod and perform a modulation to the light for projecting an image.

2. The projection system of claim 1 , wherein the optical homogenizing element is set at an optical distance from the integrating rod such that the optical elements of the optical homogenizing element produce a defocused overlapping pattern on the input of the integrating rod.

3. The projection system of claim 1 , wherein the optical homogenizing element is configured so that the light received by the integrating rod has a substantially uniform illumination.

4. The projection system of claim 1 , wherein the optical homogenizing element is a fly's-eye lens.

5. The projection system of claim 1 , wherein the optical homogenizing element is configured so that the light received by the integrating rod is substantially devoid of structure from the light source.

6. The projection system of claim 1 , further comprising:
a second modulator configured to receive the light from the first modulator and perform an additional modulation to the light for the projection system to project the image.

7. The projection system of claim 6 , wherein the optical homogenizing element is configured so that the light received by the second modulator is substantially devoid of structure from the light source.

8. The projection system of claim 6 , wherein the optical homogenizing element is configured so that the light received by the second modulator has a substantially uniform illumination.

9. The projection system of claim 1 , wherein the light transmitted through the focusing lens substantially creates a rectangular spot on the integrating rod.

10. The projection system of claim 9 , wherein the rectangular spot substantially matches a facet of the integrating rod.

11. A projection system comprising:
three color-specific lighting systems, each lighting system configured to process a respective one of a first color, a second color, and a third color, and each lighting system comprising:
a narrowband light source,
an optical collimator,
an integrating rod, and
exactly one spreading mechanism in an optical path between the optical collimator and the integrating rod, the spreading mechanism consisting of an optical homogenizing element and a focusing lens, the optical homogenizing element being selected from the group consisting of a lenslet array and a fused rod bundle, the focusing lens focusing the light from the optical homogenizing element onto an input of the integrating rod; and

a first color modulator directly illuminated by the integrating rod of the lighting system specific to the first color, such that in an optical path from the narrowband light source of the lighting system specific to the first color, light of the first color travels without being mixed and separated from light of other colors.

12. The projection system of claim 11 , wherein the optical homogenizing element is a fly's-eye lens.

13. The projection system of claim 11 , wherein each of the lighting system specific to the second color and the lighting system specific to the third color respectively illuminates corresponding second and third color modulators.

14. A method for providing a desired distribution of light in a projection system, comprising:
collimating light emitted from a narrowband light source to form collimated light;
using a single optical homogenizing element, diverging the collimated light to form diverging light having an angular distribution, the optical homogenizing element being selected from the group consisting of a lenslet array and a fused rod bundle;
using a single focusing lens, focusing the diverging light having the angular distribution to an input of an integrating rod;
transmitting light, focused to the input by the focusing lens, through the integrating rod to a first modulator; and
using the first modulator, performing a modulation to the light for projecting an image.

15. The method of claim 14 , wherein the optical homogenizing element is set at an optical distance from the integrating rod such that optical elements of the optical homogenizing element produce a defocused overlapping pattern on the input of the integrating rod, the optical elements being (a) lenses when the optical homogenizing element is a lenslet array and (b) rods when the optical homogenizing element is a fused rod bundle.

Assignees

• Dolby Laboratories Licensing Corp

Inventors

• Richards Martin J
• Dewald Duane Scott
• Wainwright Nathan
• Lippey Barret

Classifications

• G02B27/0961 Primary

  Lens arrays (lens arrays per se G02B3/0006) · CPC title

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G03B21/208

  Homogenising, shaping of the illumination light · CPC title

• G03B21/2066

  Reflectors in illumination beam (in projection beam G03B21/28) · CPC title

• G02B27/30

  Collimators · CPC title