Non-incandescent lightbulb package using light emitting diodes

• US 6,504,301 B1
• Filed: 09/03/1999
• Issued: 01/07/2003
• Est. Priority Date: 09/03/1999
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Lowery, Christopher H.
• Primary Examiner(s): Patel, Vip
• Assistant Examiner(s): WILLIAMS, JOSEPH L
• Application Number:
  US09/390,006
• Time in Patent Office: 1,222 Days
• Field of Search: 313/512, 313/506, 313/509, 313/113, 313/503, 362/800
• US Class Current: 313/512
• CPC Class Codes: F21K 9/233 specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 9/32 characterised by the arrangement of the photoluminescent material
• CPC Class Codes: F21V 9/45 by adjustment of photoluminescent elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An LED package and a method of fabricating the LED package utilize a prefabricated fluorescent member that contains a fluorescent material that can be separately tested for optical properties before assembly to ensure the proper performance of the LED package with respect to the color of the output light. The LED package includes one or more LED dies that operate as the light source of the package. Preferably, the fluorescent material included in the prefabricated fluorescent member and the LED dies of the LED package are selectively chosen, so that output light generated by the LED package duplicates natural white light. In a first embodiment of the invention, the prefabricated fluorescent member is a substantially planar plate having a disk-like shape. In a second embodiment, the prefabricated fluorescent member is a non-planar disk that conforms to and is attached to the inner surface of a concave lens. In this embodiment, the optical properties of the fluorescent member are tested by examining an integrated unit formed by the concave lens and the attached fluorescent member. In both embodiments, the LED package includes a layer of encapsulant material that is deposited between the LED dies and the fluorescent member. In a preferred embodiment, the encapsulant material is an optical grade silicone gel, which has a high thermal stability and a desired refractive index for an efficient light extraction.

Claims

1. A light source package comprising:

a light source that generates primary light having a first spectral distribution;

a layer of transparent material over said light source that encapsulates said light source; and

a nonconformal wavelength converter attached to said layer of transparent material, said wavelength converter being optically coupled to said light source to receive said primary light, said wavelength converter comprising;

a base material selected from the group consisting of acrylic, polycarbonate, and soft, optically clear, silicone rubber; and

a fluorescent material that emits secondary light in response to absorption of said primary light to produce a composite output light, the fluorescent material being contained in the base material.

2. The package of claim 1 wherein said wavelength converter is shaped as a substantially planar plate.

3. The package of claim 1 further comprising a concave lens adjacent to said wavelength converter, said wavelength converter having a non-planar disk shape that conforms to an inner surface of said concave lens.

4. The package of claim 1, wherein said transparent material of said layer that encapsulates said light source is an optical grade silicone gel.

5. The package of claim 1 wherein a physical size and shape of an exterior of said package are compatible with an exterior physical size and shape of an industry standard package selected from a group consisting of MRC-11, MR-16, MRC-16, PAR-36, PAR-38, PAR-56, and PAR-64.

6. The package of claim 1, wherein said light source includes a plurality of gallium nitride-based light emitting diodes.

7. The package of claim 1, further comprising:

a leadframe to which the light source is attached; and

a lens, the lens having a radiation pattern designed to fill a reflector.

8. The package of claim 1, further comprising a lens, the lens being attached to the wavelength converter.