Producing distinguishable light in the presence of ambient light

• US 7,724,450 B2
• Filed: 05/05/2008
• Issued: 05/25/2010
• Est. Priority Date: 05/04/2006
• Status: Expired due to Fees

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.), Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Martynov, Yourii, Stassar, Emanuel
• Primary Examiner(s): Harrington; Alicia M
• Application Number:
  US12/115,488
• Publication Number:
  US 20080212320A1
• Time in Patent Office: 750 Days
• Field of Search: 359/726, 362/341, 362/346, 362/347, 362/350
• US Class Current: 359/726
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21S 43/255 Filters
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A process and apparatus for producing distinguishable light, in the presence of ambient light is disclosed. The process involves admitting light in a first wavelength band through a first light admission port into a first optical cavity at least partially defined by a first reflector operably configured to reflect light out of the first optical cavity. The process also involves filtering ambient light reflected into the first optical cavity and entering and exiting a first space defined about the first light admission port such that ambient light outside the first wavelength band is attenuated on entry and exit from the first space.

Claims

1. A process for producing distinguishable colored light in the presence of ambient light, the process comprising:

energizing a light emitting diode (LED) first light source emitting light into a first optical cavity at least partially defined by a first reflector portion configured to reflect light emitted by the first light source out of the first optical cavity, the first light source emitting a non-white colored light within a first wavelength band;

passing the light within the first wavelength band generated by the first light source through a first filter positioned in an optical path between the first light source and the first reflector portion, the first filter attenuating light outside the first wavelength band but allowing light emitted from the first light source to pass substantially unattenuated so as to be reflected out of the first optical cavity by the first reflector portion; and

filtering, by the first filter, ambient light after the ambient light has entered the first optical cavity and reflected off the first reflector portion, such that ambient light outside said first wavelength band is attenuated by the first filter, whereby the ambient light outside said first wavelength band that has entered the first optical cavity is attenuated by the first filter prior to being reflected out of the first optical cavity by the first reflector portion, enabling the light emitted by the first light source within the first wavelength band to be more distinguishable in the presence of the ambient light.

2. The process of claim 1 wherein passing the light within the first wavelength band generated by the first light source through a first filter comprises providing the first filter around a center axis of the first reflector portion, wherein an inner surface of the first filter faces the central axis and an outer surface of the first filter faces the first reflector portion, and wherein light from the first light source enters the first filter from the inner surface of the first filter, and

wherein filtering, by the first filter, ambient light comprises filtering ambient light entering the first filter from the outer surface of the first filter.

3. The process of claim 1 wherein at least a portion of the first reflector portion has a paraboloidal shape.

4. The process of claim 1 wherein the first filter abuts an edge portion of the first reflector portion.

5. The process of claim 1 wherein the first filter is cylindrical around a center axis of the first reflector portion.

6. The process of claim 1 further comprising:

energizing an LED second light source emitting light into a second optical cavity at least partially defined by a second reflector portion configured to reflect light emitted by the second light source out of the second optical cavity, the second light source emitting non-white colored light within a second wavelength band;

passing the light within the second wavelength band generated by the second light source through a second filter positioned in an optical path between the second light source and the second reflector portion, the second filter attenuating light outside the second wavelength band but allowing light emitted from the second light source to pass substantially unattenuated so as to be reflected out of the second optical cavity by the second reflector portion; and

filtering, by the second filter, ambient light after the ambient light has entered the second optical cavity and reflected off the second reflector portion, such that ambient light outside said second wavelength band is attenuated by the second filter, whereby the ambient light outside the second wavelength band that has entered the second optical cavity is attenuated by the second filter prior to being reflected out of the second optical cavity by the second reflector portion, enabling the light emitted by the second light source within the second wavelength band to be more distinguishable in the presence of the ambient light,

wherein the first optical cavity and the second optical cavity are positioned generally coaxially with each other.

7. The process of claim 1 wherein the ambient light is unfiltered prior to being first filtered by the first filter.

8. The process of claim 1 wherein the ambient light is unfiltered when it enters the first optical cavity.

9. A lamp for producing distinguishable colored light in the presence of ambient light, the lamp comprising:

a first reflector portion surrounding a first optical cavity;

a light emitting diode (LED) first light source positioned to emit light into the first optical cavity, the first reflector portion being configured to reflect light emitted by the first light source out of the first optical cavity, the first light source emitting non-white colored light within a first wavelength band when energized;

a first filter positioned in an optical path between the first light source and the first reflector portion such that light generated by the first light source passes through the first filter before being reflected by the first reflector portion, the first filter having characteristics that attenuate light outside the first wavelength band but allow light emitted from the first light source to pass substantially unattenuated so as to be reflected out of the first optical cavity by the first reflector portion; and

the first reflector portion being configured such that ambient light reflected off the first reflector portion is filtered by the first filter before being reflected out of the first optical cavity, such that ambient light outside said first wavelength band is attenuated by the first filter, whereby the ambient light outside said first wavelength band that has entered the first optical cavity is attenuated by the first filter prior to being reflected out of the first optical cavity by the first reflector portion, enabling the light emitted by the first light source within the first wavelength band to be more distinguishable in the presence of the ambient light.

10. The lamp of claim 9 wherein the first filter is located around a center axis of the first reflector portion, wherein an inner surface of the first filter faces the central axis and an outer surface of the first filter faces the first reflector portion, wherein light from the first light source enters the first filter from the inner surface of the first filter, and wherein ambient light enters the first filter from the outer surface of the first filter.

11. The lamp of claim 9 wherein at least a portion of the first reflector portion has a paraboloidal shape.

12. The lamp of claim 9 wherein the first filter contacts an edge portion of the first reflector portion.

13. The lamp of claim 9 wherein the first filter is cylindrical around a center axis of the first reflector portion.

14. The lamp of claim 9 further comprising:

a second reflector portion surrounding a second optical cavity;

an LED second light source positioned to emit light into the second optical cavity, the second reflector portion being configured to reflect light emitted by the second light source out of the second optical cavity, the second light source emitting non-white colored light within a second wavelength band when energized;

a second filter positioned in an optical path between the second light source and the second reflector portion such that light generated by the second light source passes through the second filter before being reflected by the second reflector portion, the second filter having characteristics that attenuate light outside the second wavelength band but allow light emitted from the second light source to pass substantially unattenuated so as to be reflected out of the second optical cavity by the second reflector portion; and

the second reflector portion being configured such that ambient light reflected off the second reflector portion is filtered by the second filter before being reflected out of the second optical cavity, such that ambient light outside said second wavelength band is attenuated by the second filter, whereby the ambient light outside said second wavelength band that has entered the second optical cavity is attenuated by the second filter prior to being reflected out of the second optical cavity by the second reflector portion, enabling the light emitted by the second light source within the second wavelength band to be more distinguishable in the presence of the ambient light,

wherein the first optical cavity and the second optical cavity are positioned generally coaxially with each other.

15. The lamp of claim 14 wherein at least a portion of the second reflector portion has a paraboloidal shape.

16. The lamp of claim 14 wherein the second filter is cylindrical around a center axis of the second reflector portion.

17. The lamp of claim 14 wherein the second light source comprises a light emitting diode (LED) that emits a non-white color light different from the light emitted by the first light source.

18. The lamp of claim 9 wherein the lamp is a tail lamp of a vehicle.