Method for making a semiconductor light source

• US 6,746,885 B2
• Filed: 08/24/2001
• Issued: 06/08/2004
• Est. Priority Date: 08/24/2001
• Status: Expired due to Term

• Current Assignee: Epistar Corporation
• Original Assignee: CAO Group, Inc.
• Inventors: Cao, Densen
• Primary Examiner(s): Pert, Evan
• Assistant Examiner(s): Geyer, Scott B.
• Application Number:
  US09/938,875
• Publication Number:
  US 20030040200A1
• Time in Patent Office: 1,019 Days
• Field of Search: 362/800, 438/22, 438/26, 438/29, 438/106, 438/107, 438/116, 438/118, 438/122, 438/121, 438/125, 438/800, 174/52.1, 174/52.3, 174/260
• US Class Current: 438/26
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 29/67 characterised by the arrangement of fans
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21Y 2107/40 on the sides of polyhedrons, e.g. cubes or pyramids
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A method for making a semiconductor light source for illuminating a physical space has been invented. In various embodiments of the invention, a semiconductor such as a LED chip, laser chip, LED chip array, laser array, an array of chips, or a VCSEL chip is mounted on a heat sink. The heat sink may have multiple panels for mounting chips in various orientations. The chips may be mounted directly to a primary heat sink which is in turn mounted to a multi-panel secondary heat sink. A TE cooler and air circulation may be provided to enhance heat dissipation. An AC/DC converter may be included in the light source fitting.

Claims

1. A method for making a semiconductor light source intended to be used for emitting light to illuminate a space used by humans, the method comprising:

fabricating an enclosure, said enclosure being fabricated from a material substantially transparent to white light, and said enclosure having an interior volume,

fabricating at least one heat sink to be located within said enclosure, said heat sink being shaped to facilitate mounting of semiconductor devices thereon, said heat sink being adapted to draw heat away from semiconductor devices mounted on it,

selecting a plurality of semiconductor devices capable of emitting light emitting devices,

mounting said semiconductor devices on said heat sink(s),

applying a conversion coating for converting monochromatic light emitted by said chips to white light to the interior of said enclosure.

2. A method as recited in claim 1 further comprising the step of applying a light reflective adhesive between said semiconductor device and a heat sink.

3. A method as recited in claim 1 wherein said semiconductor devices are mounted to said heat sink by use of heat conductive adhesive located between said chip and said heat sink and serving to conduct heat from said chip to said heat sink.

4. A method as recited in claim 1 further comprising the step of placing a quantity of light reflective adhesive located between said semiconductor devices and said heat sink.

5. A method as recited in claim 1 wherein said heat sink has an air chamber within it to facilitate air flow and heat dissipation.

6. A method as recited in claim 5 wherein said air chamber has a TE cooler on it.

7. A method as recited in claim 5 further comprising placing a quantity of TE cooler material on the interior of said air chamber.

8. A method as recited in claim 1 wherein at least one of said semiconductor devices includes

a substrate on which epitaxial layers are grown,

a buffer layer located on said substrate, said buffer layer serving to mitigate differences in material properties between said substrate and other epitaxial layers,

a first cladding layer serving to confine electron movement within the chip, said first cladding layer being adjacent said buffer layer,

an active layer, said active layer emitting light when electrons jump to a valance state,

a second cladding layer, said second cladding layer positioned so that said active layer lies between cladding layers, and

a contact layer on which an electron may be mounted for powering said chip.

22. A semiconductor light source for providing illumination visible to humans of a physical space used by humans semiconductor light source being made in accordance with the process of claim 1, 9, 13, 14, 15, 18, 20 or 21.

9. A method for making a semiconductor light source comprising the steps of:

obtaining an enclosure, said enclosure being fabricated from a material substantially transparent to white light,

obtaining a base to which said enclosure may be mounted,

obtaining a secondary heat sink suitable for being located within said enclosure, said secondary heat sink being capable of drawing heat from one or more semiconductors devices, said secondary heat sink having a plurality of panels on it suitable for mounting primary heat sinks thereon, said panels on said secondary heat sink being oriented to facilitate emission of light from the semiconductor light source in desired directions around the semiconductor light source,

obtaining a plurality of primary heat sinks,

obtaining a plurality of semiconductor devices,

mounting at least one semiconductor device on each of said primary heat sinks by use of a light reflective adhesive, and mounting said primary heat sinks on said secondary heat sink panels.

10. A method as recited in claim 9 wherein said enclosure has a light conversion coating bated on its interior for convert light emitted by said semiconductor devices to white light.

11. A method as recited in claim 9 wherein said heat sink has an air chamber within it to facilitate air flow and heat dissipation.

12. A method as recited in claim 11 wherein said air chamber has a TE cooler on it.

13. A method as recited in claim 9 wherein at least one of said semiconductor devices includes

a substrate on which epitaxial layers are grown,

a buffer layer located on said substrate, said buffer layer serving to mitigate differences in material properties between said substrate and other epitaxial layers,

a first cladding layer serving to confine electron movement within the chip, said first cladding layer being adjacent said buffer layer,

an active layer, said active layer emitting light when electrons jump to a valance state, and

a second cladding layer, said second cladding layer positioned so that said active layer lies between cladding layers.

14. A method for making a semiconductor light source comprising the steps of:

obtaining an enclosure,

obtaining a heat sink suitable for being located within said enclosure, said heat sink being capable of drawing heat from one or more semiconductors devices,

obtaining a plurality of light-emitting semiconductor devices, and

mounting said semiconductor devices on said heat sink by use of a light reflective adhesive.

15. A method for making a semiconductor light source comprising the steps of:

obtaining an enclosure,

obtaining a heat sink suitable for being located within said enclosure, said heat sink being capable of drawing heat from one or more semiconductors devices,

said heat sink having an air chamber within its interior through which air may flow in order to facilitate heat dissipation,

obtaining a plurality of light-emitting semiconductor devices, and

mounting said semiconductor devices on said heat sink.

16. A method as recited in claim 15 wherein said enclosure has a light conversion coating located on its interior for converting light emitted by said semiconductor devices to white light.

17. A method as recited in claim 15 wherein said air chamber has a TE cooler on it to facilitate cooling said heat sink.

18. A method as recited in claim 15 wherein at least one of said semiconductor devices includes

a substrate on which epitaxial layers are grown,

a buffer layer located on said substrate, said buffer layer serving to mitigate differences in material properties between said substrate and other epitaxial layers,

a first cladding layer serving to confine electron movement within the chip, said first cladding layer being adjacent said buffer layer,

an active layer, said active layer emitting light when electrons jump to a valance state, and

a second cladding layer, said second cladding layer positioned so that said active layer lies between cladding layers.

19. A method as recited in claim 15 further comprising the step of applying a light conversion coating to the interior of said enclosure, said coating being capable of converting monochromatic light to white light.

20. A method for making a semiconductor light source comprising the steps of:

obtaining an enclosure,

applying a conversion coating to the interior of said enclosure, said conversion coating being capable of converting a monochromatic light to white light,

obtaining a heat sink suitable for being located within said enclosure, said heat sink being capable of drawing heat from one or more semiconductors devices,

said heat sink having an air chamber within its interior through which air may flow in order to facilitate heat dissipation,

obtaining a plurality of light-emitting semiconductor devices, and mounting said light-emitting semiconductors to said heat sink by use of a light-reflective adhesive.

21. A method for making a semiconductor light source comprising the steps of:

obtaining a secondary heat sink suitable for being located within an enclosure, an secondary heat sink being capable of drawing heat from one or more semiconductors devices,

said secondary heat sink having an air chamber within its interior through which air may flow in order to facilitate heat dissipation,

obtaining a plurality of primary heat sinks,

obtaining a plurality of light-emitting semiconductor devices,

mounting said light-emitting semiconductors to said primary heat sinks by use of a light-reflective adhesive,

mounting said primary heat sinks to said secondary heat sink,

forming an enclosure,

applying a conversion coating to the interior of said enclosure, said conversion coating

being capable of converting a monochromatic light to white light, and

locating said secondary heat sink within said enclosure.