Composite optical lens with an integrated reflector

• US 7,280,288 B2
• Filed: 06/04/2004
• Issued: 10/09/2007
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald H., Loh, Ban P.
• Primary Examiner(s): Harrington; Alicia M
• Application Number:
  US10/861,639
• Publication Number:
  US 20050270666A1
• Time in Patent Office: 1,222 Days
• Field of Search: 359726-727, 359/707, 362/335, 362/555, 438/29, 438/65, 438/111
• US Class Current: 359/726
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• 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 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 33/58 Optical field-shaping elements

Abstract

A composite optical lens is disclosed. The composite optical lens includes a concave bottom surface adapted to receive light, reflective surface adapted to reflect the received light, and optical surface through which the reflected light leaves the optical lens. The concave bottom surface defines a concave cavity allowing placement of at least a portion of a light emitting device within the concave cavity. The concave bottom surface, the optical surface, or both may have predetermined optical finish to operate on the light such as diffusing or focusing the light. The reflective surface can be coated, designed, or both for total internal reflection effect.

Claims

1. A composite optical lens of a light emitting die package, the package including a leadframe and a molded body having a top portion and a bottom portion, the molded body integrated with portions of the leadframe so that the molded body top portion is above the leadframe and the molded body bottom portion is below the leadframe, a portion of the leadframe located within the molded body defining a mounting pad on which a light emitting device (LED) assembly is mounted, the molded body having a central opening through the top portion that receives the composite optical lens, the lens comprising:

a generally semi-spherical upper portion,

a concave lower portion extending downward from the upper portion of the lens into the central opening towards the molded body bottom portion, the concave lower portion having a concave bottom surface adapted to receive light and to substantially surround the LED assembly, a concave cavity being formed between the concave bottom surface and a top surface of the leadframe within the central opening, the concave cavity at least partially filled with an encapsulant to encapsulate the LED assembly, wherein a lowest point of the concave lower portion of the lens within the central opening does not contact the top surface of the leadframe within the central opening to form a gap between the lowest point of the concave lower portion and the leadframe that is free of the encapsulant for permitting encapsulant expansion and contraction,

a reflective surface on a lower portion of the lens that is adapted to reflect the received light, and

an optical surface on the upper portion of the lens through which the reflected light leaves the lens.

2. The composite optical lens of claim 1, wherein the concave bottom surface is coated with an optical material to influence or change the light emitted by the LED assembly before it leaves the die package.

3. The composite optical of claim 2, wherein the optical material is selected from a group consisting of phosphor, diffusants, and frequency-shifting chemicals.

4. The composite optical lens of claim 1, wherein the reflective surface substantially surrounds the concave cavity.

5. The composite optical lens of claim 1, wherein the reflective surface is coated with a reflective material.

6. The composite optical lens of claim 5, wherein the reflective material is selected from a group consisting of gold, silver, and aluminum.

7. The composite optical lens of claim 1, wherein the reflective surface provides a total internal reflection (TIR) for at least a portion of the light emitted by the light emitting device.

8. The composite optical lens of claim 1, wherein the reflective surface has a given optical finish adapted to scatter the light.

9. The composite optical lens of claim 1, wherein the upper portion of the lens tapers at a ledge of the lens which rests on a horizontal surface of the molded body top portion so that the upper portion of the lens extends above the molded body top portion within the central opening.

10. A composite optical lens of a light emitting die package that has a central opening there through exposing a portion of a leadframe extending through the package, the leadframe portion within the package having an LED assembly mounted thereon, the lens comprising:

a generally semi-spherical upper portion extending upward through the central opening above an upper surface of the package,

a concave lower portion extending downward from the upper portion of the lens into the central opening, the concave lower portion having a concave bottom surface adapted to receive light and to substantially surround the LED assembly, a concave cavity being formed between the concave bottom surface and a top surface of the leadframe portion within the central opening, wherein a lowest point of the concave lower portion of the lens within the central opening does not contact the top surface of the leadframe within the central opening to form a gap between the lowest point of the concave lower portion and the leadframe,

a reflective surface on a lower portion of the lens to reflect received light, and

an optical surface on the upper portion through which the reflected light leaves the lens.

11. A composite optical lens of a light emitting die package, comprising:

a generally semi-spherical upper portion,

a concave lower portion having a concave bottom surface adapted to receive light and to substantially surround a LED assembly of the package, a concave cavity being formed in the lens and at least partially filled with an encapsulant to encapsulate the LED assembly, wherein a gap exists between a lowest point of the concave lower portion and a leadframe of the package that is free of the encapsulant,

a reflective surface on a lower portion of the lens adapted to reflect received light, and

an optical surface on the upper portion of the lens through which the reflected light leaves the lens.