Coated phosphor filler and a method of forming the coated phosphor filler

• US 6,734,466 B2
• Filed: 10/29/2002
• Issued: 05/11/2004
• Est. Priority Date: 03/05/2002
• Status: Expired due to Term

• Current Assignee: Document Security Systems, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Chua, Bee Yin
• Primary Examiner(s): Hoang, Huan
• Assistant Examiner(s): Nguyen, Thinh T
• Application Number:
  US10/282,859
• Publication Number:
  US 20030168669A1
• Time in Patent Office: 560 Days
• Field of Search: 257/98, 257/82, 257/84, 257/79, 257/81, 257/89, 257/91, 252/301
• US Class Current: 257/82
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/584 with zinc or cadmium
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/7786 with alkaline earth metals
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• 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 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

An improved coated phosphor filler for an optical device includes a plurality of individual phosphor filler particles, and a coating layer having a plastic substance coated on each of the phosphor filler particles.

Claims

1. A light emitting diode (LED) comprising

a LED-chip mounted on a contact base, said LED-chip being electrically connected to a first and a second electrically conducting frame;

and

a coated phosphor filler, said coated phosphor filler including a plurality of phosphor filler particles and covering said LED-chip, wherein said phosphor filler particles are coated with a coating layer comprising a plastic substance.

2. The light emitting diode (LED) according to claim 1, wherein said LED-chip is covered with a drop of said coated phosphor filler in a reflector cup provided in said first electrically conducting frame, and wherein said drop and at least a part of said first electrically conducting frame are over-moulded with an optical dome consisting of an optically transparent epoxy.

3. The light emitting diode (LED) according to claim 1, wherein said LED-chip and at least a part of said first electrically conducting frame are over-moulded with a mixture of a plurality of said individual phosphor filler particles and an optically transparent epoxy, said mixture forming an optical dome.

4. The light emitting diode (LED) according to claim 1, wherein the plastic substance is an optically transparent epoxy composition.

5. The light emitting diode (LED) according to claim 1, wherein said phosphor filler particles are unstable phosphor compound particles coated with a moisture-proof barrier film, the coating layer being provided on the outer surface of said barrier film.

6. The light emitting diode (LED) according to claim 1, further comprising an optical dome, said optical dome covering said LED-chip and consisting of an epoxy material.

7. The light emitting diode (LED) according to claim 1, said barrier material includes an inorganic passivation material.

8. The light emitting diode (LED) according to claim 7, said inorganic passivation material including a material selected from the group consisting of aluminium oxide (Al₂O₃), silicon monoxide (SiO), zinc sulphide (ZnS) or silicon nitride (Si₃N₄).

9. The light emitting diode (LED) according to claim 1, said epoxy composition includes hydrophobic residues forming a moisture-repellent barrier.