Solid state based illumination source for a projection display

• US 6,325,524 B1
• Filed: 01/29/1999
• Issued: 12/04/2001
• Est. Priority Date: 01/29/1999
• Status: Expired due to Term

• Current Assignee: Bench Walk Lighting, LLC
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Trutna, Jr., William R., Weber, Andreas G., Cutler, Gergory M.
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Neils, Peggy A
• Application Number:
  US09/239,571
• Time in Patent Office: 1,040 Days
• Field of Search: 362/245, 362/247, 362/241, 362/545, 362/800
• US Class Current: 362/245
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/2066 Reflectors in illumination beam in projection beam G03B21/28
• CPC Class Codes: G03B 27/545 for enlargers
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light source for generating light that is collected by an optical system that collects light leaving the light source within a predetermined acceptance angle relative to an axis defined in relation to the optical system. The light source includes a plurality of LEDs mounted on a reflecting base. Each of the LEDs generates light that leaves that LED via a top surface, a bottom surface, and one or more side surfaces of the LED. The reflecting base has a reflective surface in contact with the bottom surface of each of the LEDs. Light leaving the side surfaces of the LEDs is reflected into the acceptance angle of the optical system by a plurality of reflectors. In one embodiment of the invention, the reflectors include a plurality of reflecting facets for reflecting light leaving the side surfaces of the LEDs. The facets may be part of the reflective base or separate objects located between the LEDs. In another embodiment of the invention, the reflectors include scattering centers located between the LEDs.

Claims

1. A light source for generating light that is collected by an optical system, said optical system accepting light leaving said light source within a predetermined acceptance angle relative to an axis defined in relation to said optical system, said light source comprising:

a plurality of LEDs mounted on a reflective base, each of said LEDs generating light that leaves that LED via a top surface, a bottom surface, and one or more side surfaces of said LED, said reflective base having a reflective surface in contact with said bottom surface of each of said LEDs, and

a plurality of reflectors for reflecting light leaving said side surfaces of said LEDs into said acceptance angle of said optical system, at least one of said reflectors being located between two of said LEDs.

2. The light source of claim 1 wherein said reflectors comprise a plurality of facets for reflecting light leaving said side surfaces of said LEDs at an angle such that said light leaves said light source at an angle within said acceptance angle.

3. A light source for generating light that is collected by an optical system, said optical system accepting light leaving said light source within a predetermined acceptance angle relative to an axis defined in relation to said optical system, said light source comprising:

a plurality of LEDs mounted on a reflective base, each of said LEDs generating light that leaves that LED via a top surface, a bottom surface, and one or more side surfaces of said LED, said reflective base having a reflective surface in contact with said bottom surface of each of said LEDs, and

a plurality of reflectors for reflecting light leaving said side surfaces of said LEDs into said acceptance angle of said optical system, wherein said reflectors comprise a plurality of facets for reflecting light leaving said side surfaces of said LEDs at an angle such that said light leaves said light source at an angle within said acceptance angle, and

wherein said LEDs are mounted such that said bottom surface of each LED is in contact with one of said facets, that facet reflecting light generated in that LED and light leaving one of said side surfaces of an adjacent LED.

4. A light source for generating light that is collected by an optical system, said optical system accepting light leaving said light source within a predetermined acceptance angle relative to an axis defined in relation to said optical system, said light source comprising:

a plurality of LEDs mounted on a reflective base, each of said LEDs generating light that leaves that LED via a top surface, a bottom surface, and one or more side surfaces of said LED, said reflective base having a reflective surface in contact with said bottom surface of each of said LEDs, and

a plurality of reflectors for reflecting light leaving said side surfaces of said LEDs into said acceptance angle of said optical system, wherein said reflectors comprise a plurality of scattering particles dispersed in a transparent medium between said LEDs, said scattering particles being located such that light leaving the top of said LEDs is not scattered.