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

• US 20050051782A1
• Filed: 09/09/2003
• Published: 03/10/2005
• 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
• Granted Patent: US 7,029,935 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• 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 mold with a molten liquid that comprises a transparent plastic and a phosphor additive; and

allowing the molten liquid to solidify to produce the transmissive optical element having phosphor dispersed therein.

2. A method according to claim 1 wherein the transmissive optical element is a dome through which a light emitting device emits light and wherein the filling comprises filling a dome-shaped mold with a molten liquid that comprises a transparent plastic and a phosphor additive.

3. A method according to claim 2 further comprising:

forming a transparent core inside the dome.

4. A method according to claim 2 further comprising:

forming a transparent outer shell outside the dome.

5. A method according to claim 3 further comprising:

forming a transparent outer shell outside the dome.

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

7. A method according to claim 1 wherein the transmissive optical element is a keypad key through which a light emitting device emits light and wherein the filling comprises filling a keypad key-shaped mold with a molten liquid that comprises a transparent plastic and a phosphor additive.

8. A method according to claim 1 wherein the transmissive optical element is a keypad key face, through which a light emitting device emits light, the method further comprising:

forming a keypad key wall that is attached to the keypad key face.

9. A transmissive optical element comprising:

a shell that comprises a transparent plastic including a phosphor dispersed therein.

10. A transmissive optical element according to claim 9 wherein the phosphor is uniformly dispersed in the shell.

11. A transmissive optical element according to claim 9 wherein the phosphor is nonuniformly dispersed in the shell.

12. A transmissive optical element according to claim 9 wherein the shell is a dome-shaped shell, the transmissive optical element further comprising a transparent inner core inside the dome-shaped shell.

13. A transmissive optical element according to claim 9 wherein the shell is a dome-shaped shell, the transmissive optical element further comprising a transparent outer core outside the dome-shaped shell.

14. A transmissive optical element according to claim 12 wherein the shell is a dome-shaped shell, the transmissive optical element further comprising a transparent outer core outside the dome-shaped shell.

15. A transmissive optical element according to claim 12 wherein the transparent inner core fills the dome-shaped shell.

16. A transmissive optical element according to claim 12 in combination with a semiconductor light emitting device that is configured to emit light into and through the transparent inner core and through the dome-shaped shell, to emerge from the dome-shaped shell.

17. A transmissive optical element according to claim 16 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 transparent inner core.

18. A transmissive optical element according to claim 17 in further combination with an encapsulant between the semiconductor light emitting device and the transparent inner core.

19. A transmissive optical element according to claim 9 wherein the shell is a keypad key shell, including a keypad key face and a keypad key wall that extends from the keypad key face.

20. A transmissive optical element according to claim 19 wherein the phosphor is uniformly dispersed in the keypad key shell.

21. A transmissive optical element according to claim 19 wherein the phosphor is uniformly dispersed in the keypad key face and is not included in the keypad key wall.

22. A transmissive optical element according to claim 19 wherein the phosphor is nonuniformly dispersed in the keypad key face.

23. A light emitting device comprising:

a mounting substrate;

a semiconductor light emitting device on the mounting substrate;

a dome-shaped shell that comprises a transparent plastic including a phosphor dispersed therein, on the mounting substrate that at least partially surrounds the semiconductor light emitting device; and

a transparent inner core inside the dome-shaped shell.

24. A light emitting device according to claim 23 further comprising:

an encapsulant between the semiconductor light emitting device and the transparent inner core.

25. A light emitting device according to claim 24 wherein the mounting substrate includes therein a cavity, wherein the semiconductor light emitting device is at least partially in the cavity, wherein the dome-shaped shell is on the mounting substrate surrounding the cavity and wherein the encapsulant is in the cavity.

26. A light emitting device according to claim 23 further comprising:

a transparent outer shell outside the dome-shaped shell.