Fluorescent dye added to epoxy of light emitting diode lens

• US 5,847,507 A
• Filed: 07/14/1997
• Issued: 12/08/1998
• Est. Priority Date: 07/14/1997
• Status: Expired due to Term

• Current Assignee: Philips Lighting North America Corporation (Koninklijke Philips N.V.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Helbing, Rene P., Butterworth, Mark M.
• Primary Examiner(s): PATEL, NIMESHKUMAR D
• Application Number:
  US08/892,049
• Time in Patent Office: 512 Days
• Field of Search: 313/483, 313/498, 313/501, 313/512, 313/110, 313/112
• US Class Current: 313/512
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A process and apparatus is described to produce efficient light emission over a broad portion of the visible spectrum. A lens containing a fluorescent dye is over molded to a short wavelength light emitter (e.g., a blue LED or laser diode) placed within a reflector cup. The fluorescent dye absorbs at least a portion of the light emitted by the diode and re-emits light of a second, longer wavelength. Concentration of the dye within the lens can be varied to control the extent of a region within the lens where most of the light is re-emitted so the remaining portion of the lens can focus the light. One can readily and consistently tailor the color of the light emitted from the lens through selection of the number and types of fluorescent dyes added to the lens, and through their relative concentrations. Inventory is reduced and there are no additional steps required when building varied color LEDs. One simply controls the color of the LED being made by selecting from one of several possible fluorescent dye-containing lens epoxies.

Claims

1. A light source, comprising:

a light emitter, to emit light of a first wavelength; and

a lens to focus light emitted from the light source, the lens including a non-scattering fluorescent material to absorb light of the first wavelength and re-emit light of a second wavelength.

2. The light source as set forth in claim 1, wherein concentration of the fluorescent material in the lens is such that a significant portion of light re-emission occurs in a particular region of the lens, thereby permitting the lens to focus the re-emitted light.

3. The light source as set forth in claim 1, wherein the fluorescent material is an organic dye.

4. The light source as set forth in claim 1, comprising a second fluorescent material that absorbs light of the first wavelength and re-emits light of a third wavelength.

5. The light source as set forth in claim 1, comprising a second fluorescent material that absorbs light of the second wavelength and re-emits light of a third wavelength.

6. The light source as set forth in claim 1, wherein the light emitter is a light emitting diode.

7. The light source as set forth in claim 1, wherein the light emitter is a laser diode.

8. A method of providing a light source, the method comprising the steps of:

emitting light of a first wavelength from a light emitter; and

using a lens to focus light emitted from the light source, the lens including a non-scattering fluorescent material to absorb light of the first wavelength and re-emit light of a second wavelength.

9. The light source method as set forth in claim 8, wherein concentration of the fluorescent material in the lens is such that a significant portion of light re-emission occurs in a particular region of the lens, thereby permitting the lens to focus the re-emitted light.

10. The light source method as set forth in claim 8, wherein the fluorescent material is an organic dye.

11. The light source method as set forth in claim 8, comprising the step wherein a second fluorescent material absorbs light of the first wavelength and re-emits light of a third wavelength.

12. The light source method as set forth in claim 8, comprising the step wherein a second fluorescent material absorbs light of the second wavelength and re-emits light of a third wavelength.

13. The light source method as set forth in claim 8, wherein the light emitter is a light emitting diode.

14. The light source method as set forth in claim 8, wherein the light emitter is a laser diode.

15. A light source, comprising:

a light emission means for emitting light of a first wavelength; and

a focusing means for focusing light emitted from the light source, the focusing means including a non-scattering fluorescent means for absorbing light of the first wavelength and re-emitting light of a second wavelength.

16. The light source as set forth in claim 15, wherein concentration of the fluorescent means in the focusing means is such that a significant portion of light re-emission occurs in a particular region of the focusing means, thereby permitting the focusing means to focus the re-emitted light.

17. The light source as set forth in claim 15, wherein the fluorescent means is an organic dye.

18. The light source as set forth in claim 15, comprising a second fluorescent means for absorbing light of the first wavelength and re-emitting light of a third wavelength.

19. The light source as set forth in claim 15, comprising a second fluorescent means for absorbing light of the second wavelength and re-emitting light of a third wavelength.

20. The light source as set forth in claim 15, wherein the light emission means is a light emitting diode.

21. The light source as set forth in claim 15, wherein the light emission means is a laser diode.