Multicolor light emitting device

• US 5,841,177 A
• Filed: 07/10/1997
• Issued: 11/24/1998
• Est. Priority Date: 06/25/1993
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Tanaka, Toshiaki, Fujimura, Norio, Komoto, Satoshi
• Primary Examiner(s): Saadat, Mahshid D.
• Assistant Examiner(s): CLARK, JASMINE JHIHAN B
• Application Number:
  US08/890,927
• Time in Patent Office: 502 Days
• Field of Search: 257/431, 257/88, 257/81, 257/89, 257/95, 257/98, 257/99, 257/100, 257/433
• US Class Current: 257/431
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 24/45 of an individual wire connector
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

A semiconductor light emitting device includes at least two semiconductor light emitting elements which emit different colors of light to each other. The device further includes a lead frame for supporting the light emitting elements and a resin molding for sealing these elements. The external form of this resin molding is an ellipsoid or a part of an ellipsoid in which the curvature in the perpendicular direction to the element row is designed to be smaller than that in the parallel direction to the row. As a result, the device has a widely spread mixed color range especially in the perpendicular direction to the element row and high luminous intensity especially in the parallel direction to the element row. So, a multicolor light emitting device having a high ability of color mixture as well as high luminous intensity can be obtained.

Claims

1. A light emitting device, comprising:

a plurality of semiconductor light emitting elements aligned in a row for emitting at least two different colors of light;

a lead frame connected with said semiconductor light emitting elements for supplying electric energy to said semiconductor light emitting elements; and

a transparent molding for sealing said semiconductor light emitting elements and providing an exterior convex ellipsoidal surface through which the light rays of said at least two different colors are passed, a cross section of said molding containing said light emitting elements being an ellipse having a major axis parallel to said row of semiconductor elements and a minor axis perpendicular to said row of elements, said exterior convex ellipsoidal surface having a long radius of exterior surface curvature in the direction of the major axis and a short radius in the direction of the minor axis, thereby to provide a region of enhanced color mixture of the light rays passed through the exterior convex ellipsoidal surface corresponding to a ratio of the long radius to the short radius.

2. The multicolor light emitting device as claimed in claim 1, including at least three spaced and aligned semiconductor light emitting elements, one of which emits red light, another of which emits green light, and the other of which emits blue light.

3. The multicolor light emitting device as claimed in claim 1, wherein said resin molding is so formed that the ratio of the long radius of exterior surface curvature in the direction parallel to the major axis, to the short radius in the direction of the minor axis, is more than 1.2.

4. The multicolor light emitting device as claimed in claim 3, wherein said at least three semiconductor light emitting elements include a GaAlAs or GaAsP light emitting diode for generating red light, a GaP or InGaAlP light emitting diode for generating green light, and a SiC light emitting diode for generating blue light.