High efficiency illuminator

• US 5,471,371 A
• Filed: 01/08/1993
• Issued: 11/28/1995
• Est. Priority Date: 01/08/1993
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Koppolu, Prasad M., Chinniah, Jeyachandrabose, Fallahi, Amir
• Primary Examiner(s): Dority, Carroll B.
• Application Number:
  US08/002,006
• Time in Patent Office: 1,054 Days
• Field of Search: 362/241, 362/245, 362/247, 362/297, 362/328, 362/347, 362/800, 362/32, 362/307
• US Class Current: 362/555
• CPC Class Codes: F21S 4/28 rigid, e.g. LED bars
• CPC Class Codes: F21S 41/173 Fluorescent light sources
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21S 43/15 Strips of light sources
• CPC Class Codes: F21S 43/241 of complex shape
• CPC Class Codes: F21S 43/251 the light guides being used to transmit light from remote light sources
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/04 Optical design
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An illuminator for use with a light source having a light distribution pattern within a solid angle of 2π steradians. The light source comprises or includes a series of LED'"'"'s or light pipes positioned at or near a focal point of a reflective surface and inclined at an angle to a focal axis of the reflective surface such that all of the light from the light source is collected and distributed by the reflective surface. Whereby the reflective surface is optimized to confine the light output only to the required photometric zones thus maximizing the efficiency of the illuminator.

Claims

1. An illuminator for use with a vehicle comprising:

a light source, said light source having a distribution pattern within a solid angle of 2π

steradians; and

a reflective surface for collecting and distributing substantially all of the light emitted from said light source, said reflective surface having a focal point and a focal axis wherein said light source is positioned near the focal point and inclined with respect to said focal axis such that the light collected and distributed by said reflective surface does not strike said light source.

2. An illuminator as set forth in claim 1 wherein said distribution pattern is a conical pattern having a cone angle of 2θ

; and

said light source is inclined with respect to an axis perpendicular said focal axis at an angle equal to 90°

-θ

.

3. An illuminator as set forth in claim 1 wherein said reflective surface includes a semi-paraboloidal shaped surface.

4. An illuminator as set forth in claim 1 wherein said reflective surface includes a semi-ellipsoidal shaped surface.

5. An illuminator as set forth in claim 1 wherein said reflective surface including an elongated semi-parabolic shaped channel.

6. An illuminator as set forth in claim 5 wherein said collected light is distributed in a predetermined beam pattern and the position of said light source with respect to the focal axis is variable and controls the predetermined beam pattern.

7. An illuminator as set forth in claim 5 wherein said elongated semi-parabolic shaped channel has an arcuate longitudinal axis.

8. An illuminator as set forth in claim 1 including a plurality of reflective surfaces and a plurality of light sources.

9. An illuminator as set forth in claim 1 wherein said light source includes a light guide transmitting light from a remote light source.

10. An illuminator as set forth in claim 1 wherein said light source includes a light emitting diode.

11. An illuminator as set forth in claim 1 including a lens for forming said distributed light into a desired beam pattern.

12. An illuminator for use with a vehicle comprising:

a reflective surface having a focal point and a focal axis;

a light source emitting light in a conical distribution pattern, positioned near the focal point and inclined with respect to said focal axis, said light source illuminating only said reflective surface so that said reflective surface collects and distributes substantially all of the light emitted from said light source; and

said light source positioned such that the light collected and distributed by said reflective surface does not strike said light source.

13. A method of forming a light beam for use with a vehicle comprising,

emitting light from a light source, said light source emitting light in a distribution pattern having a solid angle of less than 2π

steradians;

collecting the light emitted from the light source on a reflective surface, said reflective surface having a focal point and a focal axis, wherein substantially all of the light emitted by said light source strikes said reflective surface;

distributing the light from said reflective surface in a predetermined specified beam pattern; and

positioning said light source near the focal point such that the light distributed from the reflective surface does not strike the light source.

14. A method of forming a light beam as set forth in claim 13 including passing the light through a lens to form the light into said desired specified beam pattern.

15. A method of forming a light beam as set forth in claim 13 wherein the reflective surface includes a semi-paraboloidal surface of a configuration generated by the steps of selecting a required height of the light beam, selecting the distribution pattern of the light source;

utilizing the required height of the light beam and the distribution pattern of the light source to calculate a focal point of the semi-paraboloidal surface and determining the distance between the focal point and a vertex of the semi-paraboloidal surface from which the shape of the semi-parabolodial surface can be determined.

16. A method of forming a light beam as set forth in claim 13 wherein the reflective surface includes a semi-ellipsoidal surface of a configuration generated by the steps of selecting a required height of the light beam, selecting the distribution pattern of the light source;

determining a beam spread angle; and

utilizing the required height of the light beam, the distribution pattern of the light source and the beam spread angle to calculate a focal point of the semi-ellipsoidal surface from which the shape of the semi-ellipsoidal surface call be determined.

17. A method of forming a light beam as set forth in claim 13 wherein the reflective surface includes an elongated surface having a semi-parabolic cross-section, the configuration of the semi-parabolic cross-section generated by the steps of selecting a required height of the light beam, selecting a distribution pattern of the light source;

utilizing the required height of the light beam and the distribution pattern of the light source to calculate a focal point of the semi-parabolic cross-section surface and determining the distance between the focal point and a vertex of the semi-parabolic cross-section from which the shape of the semi-parabolic cross-section can be determined.