Light emitting diode and method for fabricating the same

• US 7,213,945 B2
• Filed: 05/16/2003
• Issued: 05/08/2007
• Est. Priority Date: 05/17/2002
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: CCS Corporation
• Inventors: Yoneda, Kenji, Inagaki, Yasuhiko, Amano, Takahiro
• Primary Examiner(s): Luebke; Renee
• Assistant Examiner(s): Shallenberger; Julie A.
• Application Number:
  US10/514,221
• Publication Number:
  US 20050174779A1
• Time in Patent Office: 1,453 Days
• Field of Search: 362/267, 362308-310, 362/327, 362/329
• US Class Current: 362/309
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting diode unit comprises a light emitting element D1, a base 1 having a heat dissipating member 12 that dissipates heat generated by the light emitting element D1, and a first lens 2 comprising a reflecting element 214 that reflects light R2 traveling outside of a predetermined angle among the emitted light R emitted by the light emitting element D1 and a refracting element F that refracts light R1 traveling inside of the predetermined angle among the emitted light R, each of which is formed integrally, with the first lens 2 mounted integrally on the base 1, and the emitted light R emitted from the light emitting element D1 is made to travel generally toward the same direction by the reflecting element 214 and the refracting element F.

Claims

1. A light emitting diode unit comprising;

a super high luminance light emitting element, that can pass an electric current of 250 mA;

a base including a heat dissipating member that dissipates heat generated by the light emitting element;

a laminated insulating material covering over the heat dissipating member, and a wiring pattern arranged on the insulating material, wherein a boundary between a P-layer and an N-layer of the light emitting element is within several μ

m to a the wiring pattern, and that the light emitting element is mounted on the wiring pattern via a spacer having a predetermined thickness; and

a first lens comprising a reflecting element that reflects light traveling outside of a predetermined angle among the light emitted by the light emitting element and a refracting element that refracts light traveling inside of the predetermined angle among the light emitted by the light emitting element, each of which is integrally formed, with the first lens mounted integrally on the base, wherein the emitted light from the light emitting element is made to travel generally toward the same direction by the reflecting element and the refracting element,

wherein the refracting element is a Fresnel lens comprising a convex lens portion arranged at the Fresnel lens center and multiple orbicular zone lens portions having an aspherical refracting surface arranged concentrically around the convex lens portion,

a distance between each orbicular zone lens portion and the plane of the light emitting element, parallel to the optical axis, is set to increase for the orbicular zone lens portions located closer to the center, and

an angle, between a connecting surface between the refracting surface of one orbicular zone lens portion and a refracting surface of the orbicular zone lens portion of its outer radial neighbor and the optical axis, is set to be identical with or smaller than an angle between the light traveling from an end of the light emitting element toward a bottom end of the connecting surface and the optical axis.

2. The light emitting diode unit described in claim 1, and characterized in that the first lens is provided with an element protective portion that accommodates the light emitting element, and that a transparent member of resin, fills the element protective portion.

3. The light emitting diode unit described in claim 1, and characterized in that a spacer whose coefficient of heat conductivity is larger than that of the heat dissipating member is arranged between the heat dissipating member and the light emitting element.

4. A light emitting diode unit comprising:

a super high luminance light emitting element, that can pass an electric current of 250 mA;

a base including a heat dissipating member that dissipates heat generated by the light emitting element;

a laminated insulating material covering over the heat dissipating member, and a wiring pattern arranged on the insulating material, wherein a boundary between the P-layer and an N-layer of the light emitting element is within several μ

m to the wiring pattern, and that the light emitting element is mounted on the wiring pattern via a spacer having a predetermined thickness;

a first lens comprising a reflecting element that reflects light traveling outside of a predetermined angle among the light emitted by the light emitting element and a refracting element that refracts light traveling inside of the predetermined angle among the light emitted by the light emitting element, each of which is integrally formed, with the first lens mounted integrally on the base, wherein the emitted light from the light emitting element is made to travel generally toward the same direction by the reflecting element and the refracting element; and

a spacer whose coefficient of heat conductivity is larger than that of the heat dissipating member is arranged between the heat dissipating member and the light emitting element,

wherein, the base further comprises a wiring board mounted on a surface of the heat dissipating member and a wire which supplies electric power to the light emitting element is directly connected to the wiring board.

5. The light emitting diode unit described in claim 4, and characterized in that the spacer is electrically conductive.

6. The light emitting diode unit described in claim 5, and characterized in that a thermal expansion coefficient of the spacer has a value between a thermal expansion coefficient of the light emitting element and a thermal expansion coefficient of the heat dissipating member.

7. The light emitting diode unit described in claim 6, and characterized in that the thermal expansion coefficient of the spacer has a value between the thermal expansion coefficient of the light emitting element and the thermal expansion coefficient of the heat dissipating member, wherein the value is closer to the thermal expansion coefficient of the light emitting element than the thermal expansion coefficient of the heat dissipating member.