Lens compression molded over LED die

• US 9,081,167 B2
• Filed: 03/14/2008
• Issued: 07/14/2015
• Est. Priority Date: 11/15/2004
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.), Koninklijke Philips N.V.
• Inventors: Basin, Grigoriy, West, Robert Scott, Martin, Paul S., Harbers, Gerard, Smits, Willem H., Hendriks, Robert F. M., Konijn, Frans H.
• Primary Examiner(s): REAMES, MATTHEW L
• Application Number:
  US12/049,239
• Publication Number:
  US 20080157114A1
• Time in Patent Office: 2,678 Days
• Field of Search: 257/98, 257/99, 257/E33.073
• US Class Current: 1/1
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/056 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/81 using a bump connector
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 33/46 : Reflective coating, e.g. dielectric Bragg reflector
• 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 33/54 : having a particular shape
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence

Abstract

One or more LED dice are mounted on a support structure. The support structure may be a submount with the LED dice already electrically connected to leads on the submount. A mold has indentations in it corresponding to the positions of the LED dice on the support structure. The indentations are filled with a liquid optically transparent material, such as silicone, which when cured forms a lens material. The shape of the indentations will be the shape of the lens. The mold and the LED dice/support structure are brought together so that each LED die resides within the liquid silicone in an associated indentation. The mold is then heated to cure (harden) the silicone. The mold and the support structure are then separated, leaving a complete silicone lens over each LED die. This over molding process may be repeated with different molds to create concentric shells of lenses. Each concentric lens may have a different property, such as containing a phosphor, providing a special radiation pattern, having a different hardness value, or curable by a different technique (e.g., UV vs. heat).

Claims

1. An intermediate product during the fabrication of a light emitting device, the device having been separated from a mold, defining a lens, to form an encapsulating lens over the die, the mold not including a liquid channel through which liquid lens material is injected into the mold, the device being at a time immediately after the LED die and lens are separated from the mold, the device comprising:

a light emitting diode (LED) die attached to a support structure; and

a molded lens, entirely formed of cured lens material as a continuous homogeneous member, directly over, encapsulating, and contacting the LED die, the lens being completely composed of the cured lens material, wherein there is no lens material extending from the lens that is remaining from a liquid channel immediately after the LED die and lens are separated from the mold,

wherein there is no additional solid material covering and in contact with the molded lens.

2. The device of claim 1 wherein the support structure comprises a submount having metal leads in electrical contact with metal contacts on the LED die.

3. The device of claim 1 wherein the LED die is one of a plurality of LED dice affixed to the support structure.

4. The device of claim 1 wherein the lens is generally hemispherical to emit light in a Lambertian pattern.

5. The device of claim 1 wherein the lens is generally rectangular with rounded edges.

6. The device of claim 1 wherein the lens contains a first phosphor.

7. The device of claim 1 further comprising a backlight for a liquid crystal display, the backlight incorporating the LED and the lens.

8. The device of claim 1 further comprising a rear projection television, the television incorporating the LED and the lens.

9. The device of claim 1 wherein a shape of the lens is symmetrical about a center axis.