Transmissive optical elements including transparent plastic shell having a phosphor dispersed therein, and methods of fabricating same

• US 7,029,935 B2
• Filed: 09/09/2003
• Issued: 04/18/2006
• Est. Priority Date: 09/09/2003
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald H., Loh, Ban
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nguyen, Dao H.
• Application Number:
  US10/659,240
• Publication Number:
  US 20050051782A1
• Time in Patent Office: 952 Days
• Field of Search: 257/80, 257/89, 257/98, 313/501, 313/503, 438/26, 438/29, 438/116, 200/314, 349/69, 379/433.07
• US Class Current: 438/29
• CPC Class Codes: B29C 39/003 characterised by the choice of material
• CPC Class Codes: B29C 45/0001 characterised by the choice of material
• CPC Class Codes: B29D 11/0074 Production of other optical elements not provided for in B29D11/00009- B29D11/0073
• CPC Class Codes: B29K 2995/0018 having particular optical properties, e.g. fluorescent or phosphorescent
• CPC Class Codes: B29L 2011/00 Optical elements, e.g. lenses, prisms
• CPC Class Codes: B29L 2031/3431 Telephones, Earphones
• CPC Class Codes: H01H 13/83 characterised by legends, e.g. Braille, liquid crystal displays, light emitting or optical elements
• CPC Class Codes: H01H 2219/014 LED
• CPC Class Codes: H01H 2219/052 Phosphorescence
• CPC Class Codes: H01H 2221/07 transparent
• CPC Class Codes: H01H 2229/046 Multi-colour or double shot injection moulding
• CPC Class Codes: H01L 2224/48091 Arched
• 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
• 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: H01L 33/58 Optical field-shaping elements

Abstract

A transmissive optical element is fabricated by filling a mold with molten liquid that includes a transparent plastic and a phosphor additive, and allowing the molten liquid to solidify to produce the transmissive optical element having phosphor dispersed therein. Accordingly, a separate phosphor coating or phosphor-containing encapsulant need not be used. Transmissive optical elements include a shell made of transparent plastic with a phosphor dispersed therein. The phosphor may be uniformly and/or nonuniformly dispersed in the shell.

Claims

1. A method for forming a transmissive optical element comprising:

filling a dome-shaped mold with a molten liquid that comprises a transparent plastic and a phosphor additive;

allowing the molten liquid to solidify to produce a solid dome-shaped transmissive optical element having phosphor dispersed therein and including a dome-shaped inner surface and a dome-shaped outer surface; and

forming a solid transparent dome-shaped shell including a dome-shaped inner surface and a dome-shaped outer surface directly on the dome-shaped inner surface and/or directly on the dome-shaped outer surface of the solid dome-shaped transmissive optical element having phosphor disposed therein.

2. A method according to claim 1 wherein the filling is preceded by forming the solid transparent dome-shaped shell and wherein the filling comprises filling a dome-shaped mold that includes the solid transparent dome-shaped shell with a molten liquid that comprises a transparent plastic and a phosphor additive.

3. A transmissive optical element comprising:

a first solid dome-shaped shell that comprises a transparent plastic including a phosphor dispersed therein, the first solid dome-shaped shell including a dome-shaped inner surface and a dome-shaped outer surface; and

a second solid dome-shaped shell including a dome-shaped inner surface and a dome-shaped outer surface directly on the dome-shaped inner and/or outer surface of the first solid dome-shaped shell.

4. A transmissive optical element according to claim 3 wherein the phosphor is uniformly dispersed in the first solid dome-shaped shell.

5. A transmissive optical element according to claim 3 wherein the phosphor is nonuniformly dispersed in the first solid dome-shaped shell to provide an indicia in the first solid dome-shaped shell.

6. A transmissive optical element according to claim 3 in combination with a semiconductor light emitting device that is configured to emit light into and through the first and second solid dome-shaped shells, to emerge from the first and second solid dome-shaped shells.

7. A transmissive optical clement according to claim 6 in further combination with a mounting substrate that is adjacent the semiconductor light emitting device such that the semiconductor light emitting device is between the mounting substrate and the first and second solid dome-shaped shells.

8. A transmissive optical element according to claim 7 in further combination with an encapsulant between the semiconductor light emitting device and the first and second solid dome-shaped shells.

9. A transmissive optical element according to claim 3 wherein the second solid dome-shaped shell is directly on the inner surface of the first solid dome-shaped shell, the transmissive optical element further comprising a third solid dome-shaped shell directly on the outer surface of the first solid dome-shaped shell.