Apparatus having blue light source, dichroic mirror and phosphor converter to generate white light

• US 10,458,612 B2
• Filed: 12/21/2017
• Issued: 10/29/2019
• Est. Priority Date: 06/26/2014
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Bhakta, Vikrant R.
• Primary Examiner(s): May, Robert J
• Application Number:
  US15/850,698
• Publication Number:
  US 20180135823A1
• Time in Patent Office: 677 Days
• CPC Class Codes: F21S 41/148 the main emission direction of the LED being perpendicular to the optical axis
• CPC Class Codes: F21S 41/16 Laser light sources
• CPC Class Codes: F21S 41/173 Fluorescent light sources
• CPC Class Codes: F21S 41/176 Light sources where the light is generated by photoluminescent material spaced from a primary light generating element
• CPC Class Codes: F21S 41/255 Lenses with a front view of circular or truncated circular outline
• CPC Class Codes: F21S 41/265 Composite lenses; Lenses with a patch-like shape
• CPC Class Codes: F21S 41/30 characterised by reflectors
• CPC Class Codes: F21S 41/33 Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature
• CPC Class Codes: F21S 41/645 by electro-optic means, e.g. liquid crystal or electrochromic devices
• CPC Class Codes: F21S 41/675 by moving reflectors
• CPC Class Codes: G03B 21/204 using secondary light emission, e.g. luminescence or fluorescence using different colours G03B33/00; if related to video signals H04N9/3197
• CPC Class Codes: H01S 5/0071 for beam steering, e.g. using a mirror outside the cavity to change the beam direction
• CPC Class Codes: H01S 5/0087 for illuminating phosphorescent or fluorescent materials, e.g. using optical arrangements specifically adapted for guiding or shaping laser beams illuminating these materials
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

An illumination apparatus is provided that includes a yellow phosphor converter to receive a blue laser light beam and to convert a portion of the blue laser light beam to yellow light, a dichroic mirror optically coupled to the yellow phosphor converter to receive the phosphor-emitted light beam and to filter the phosphor-emitted light beam to provide a dichroic-filtered light beam, the dichroic mirror configured to pass yellow light and to reflect at least some blue light, and a blue light source optically coupled to the dichroic mirror to provide a blue light beam, the dichroic mirror configured to reflect the blue light beam in a same direction as the dichroic-filtered light beam.

Claims

1. An apparatus comprising:

a first blue light source configured to provide a first blue light beam, the first blue light source being a blue laser light source, and the first blue light beam being a blue laser light beam;

a collimating lens, optically coupled to the first blue light source, configured to collimate the first blue light beam into a collimated blue light beam;

an optical diffuser, optically coupled to the collimating lens, configured to optically homogenize the collimated blue light beam into a top hat spatially distributed beam;

a yellow phosphor converter configured to convert the top hat spatially distributed beam into a phosphor-emitted light beam, at least a majority of the phosphor-emitted light beam being yellow light converted from blue light of the top hat spatially distributed beam;

condensing and collimating lenses, optically coupled to the yellow phosphor converter, configured to condense and collimate the phosphor-emitted light beam into a condensed and collimated phosphor-emitted light beam;

a dichroic mirror, optically coupled to the condensing and collimating lenses, configured to filter the condensed and collimated phosphor-emitted light beam into a dichroic-filtered light beam passed by the dichroic mirror, including by passing yellow light and reflecting at least some blue light; and

a second blue light source, optically coupled to the dichroic mirror, configured to provide a second blue light beam, the dichroic mirror configured to reflect the second blue light beam in a same direction as the dichroic-filtered light beam to generate a white light beam.

2. The apparatus of claim 1, wherein the yellow phosphor converter is one selected from a group consisting of a yellow phosphor plate and a yellow phosphor wheel.

3. The apparatus of claim 1, wherein the second blue light source includes a blue light emitting diode.

4. The apparatus of claim 1, wherein a portion of the phosphor-emitted light beam is unconverted blue laser light.

5. The apparatus of claim 1, wherein the dichroic mirror is configured to reflect all blue light.

6. The apparatus of claim 1, wherein the apparatus is a component of a headlamp.

7. The apparatus of claim 1, wherein the phosphor-emitted light beam has a same direction as the top hat spatially distributed beam.

8. A headlamp, comprising:

a first blue light source configured to provide a first blue light beam, the first blue light source being a blue laser light source, and the first blue light beam being a blue laser light beam;

a collimating lens, optically coupled to the first blue light source, configured to collimate the first blue light beam into a collimated blue light beam;

an optical diffuser, optically coupled to the collimating lens, configured to optically homogenize the collimated blue light beam into a top hat spatially distributed beam;

a yellow phosphor converter configured to convert the top hat spatially distributed beam into a phosphor-emitted light beam, at least a majority of the phosphor-emitted light beam being yellow light converted from blue light of the top hat spatially distributed beam;

condensing and collimating lenses, optically coupled to the yellow phosphor converter, configured to condense and collimate the phosphor-emitted light beam into a condensed and collimated phosphor-emitted light beam;

a dichroic mirror, optically coupled to the condensing and collimating lenses, configured to filter the condensed and collimated phosphor-emitted light beam into a dichroic-filtered light beam passed by the dichroic mirror, including by passing yellow light and reflecting at least some blue light; and

a second blue light source, optically coupled to the dichroic mirror, configured to provide a second blue light beam, the dichroic mirror configured to reflect the second blue light beam in a same direction as the dichroic-filtered light beam to generate a white light beam;

a spatial light modulator configured to modulate the white light beam at a pixel level to generate an image;

illumination optics, optically coupled between the dichroic mirror and the spatial light modulator, the illumination optics configured to illuminate the spatial light modulator with the white light beam; and

projection optics, optically coupled to the spatial light modulator, configured to receive the generated image and project a larger version of the generated image at a distance away from the headlamp.

9. The headlamp of claim 8, wherein the spatial light modulator is a digital micromirror device.

10. The headlamp of claim 8, wherein the yellow phosphor converter is one selected from a group consisting of a yellow phosphor plate and a yellow phosphor wheel.

11. The headlamp of claim 8, wherein a portion of the phosphor-emitted light beam is unconverted blue laser light.

12. The headlamp of claim 8, wherein the dichroic mirror is configured to reflect all blue light.

13. The headlamp of claim 8, wherein the phosphor-emitted light beam has a same direction as the top hat spatially distributed beam.

14. A method comprising:

providing a first blue light beam, the first blue light beam being a blue laser light beam;

with a collimating lens, collimating the first blue light beam into a collimated blue light beam;

with an optical diffuser, optically homogenizing the collimated blue light beam into a top hat spatially distributed beam;

with a yellow phosphor converter, converting the top hat spatially distributed beam into a phosphor-emitted light beam, at least a majority of the phosphor-emitted light beam being yellow light converted from blue light of the top hat spatially distributed beam;

condensing and collimating the phosphor-emitted light beam into a condensed and collimated phosphor-emitted light beam;

with a dichroic mirror, filtering the condensed and collimated phosphor-emitted light beam into a dichroic-filtered light beam passed by the dichroic mirror, including by passing yellow light and reflecting at least some blue light;

providing a second blue light beam; and

with the dichroic mirror, reflecting the second blue light beam in a same direction as the dichroic-filtered light beam to generate a white light beam.

15. The method of claim 14, wherein the phosphor-emitted light beam has a same direction as the top hat spatially distributed beam.