Multiple channel illumination system

• US 7,390,097 B2
• Filed: 08/23/2004
• Issued: 06/24/2008
• Est. Priority Date: 08/23/2004
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Magarill, Simon
• Primary Examiner(s): Dowling; William C.
• Application Number:
  US10/923,945
• Publication Number:
  US 20060039140A1
• Time in Patent Office: 1,401 Days
• Field of Search: 353/31, 353/20, 353/30, 353/33, 353/34, 353/37, 353/99, 353/102, 353/94, 353/38, 362/227, 362/231, 362/235, 362/800
• US Class Current: 353/94
• CPC Class Codes: F21V 19/001 the light sources being semiconductors devices, e.g. LEDs
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G02B 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• CPC Class Codes: G02B 27/102 for generating a colour image from monochromatic image signal sources
• CPC Class Codes: G02B 27/123 The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power
• CPC Class Codes: G02B 27/149 using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

An illumination system, used for illuminating a target area, includes a plurality of light generating elements and a plurality of light collection units disposed to collect light from respective light generating elements. Imaging lens units are disposed to relay images of respective light collection units to the target area, light from different light generating elements overlapping at the target area. In some embodiments, the illumination system also includes color combining elements to combine light from differently colored light generating elements. The illumination system may be used in a projection system, with the light from the illumination system incident on an image-forming device placed at the target area.

Claims

1. An illumination unit for illuminating a target area, comprising:

a plurality of light generating elements;

a plurality of light collection units disposed to collect light from respective light generating elements; and

a plurality of imaging lens units disposed to relay images of respective light collection units to proximate the target area, light from different light generating elements overlapping at the target area, wherein the light generating elements are arranged on a planar surface, wherein the illumination axis is positioned centrally with respect to the target area, and wherein the imaging lens units positioned at an increased lateral distance from the illumination axis have an increased optical axis offset with respect to the light received from the respective light collecting optical element.

2. A unit a recited in claim 1, wherein the light generating elements arc light emitting diodcs(LEDs).

3. A unit as recited in claim 1, wherein the light propagating from each of the light collection units towards its respective imaging lens unit propagates generally along a direction parallel to a single illumination axis.

4. A unit as recited in claim 1, wherein each image substantially illuminates the entire target area.

5. A unit as recited in claim 1, wherein an image-forming device is positioned at the target area.

6. A unit as recited in claim 5, further comprising a field lens disposed between the image-forming device and the plurality of imaging lens units.

7. A unit as recited in claim 5, wherein the image-forming device comprises one of a liquid crystal image-forming device and an array of individually rotatable mirrors.

8. A unit as recited in claim 5, further comprising a control unit coupled to the image-forming device to control an image formed by the image-forming device and a projection lens unit disposed to project image light received from the image-forming device.

9. A unit as recited in claim 1, wherein the plurality of imaging lens units comprises a plurality of lenses, light from each light source being imaged by at least one respective lens of the plurality of lenses.

10. A unit as recited in claim 9, wherein the lenses have substantially the same focal length.

11. A unit as recited in claim 1, wherein the plurality of light collection units comprises arrangements of at least one lens associated with each light generating clement.

12. A unit as recited in claim 1, wherein the light generating elements emit light of the same color.

13. A unit as recited in claim 1, wherein at least one of the light generating elements emits light of a color different from other light generating elements.