Semiconductor light emitting device

• US 5,519,720 A
• Filed: 01/05/1994
• Issued: 05/21/1996
• Est. Priority Date: 03/04/1993
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Omura, Etsuji, Shigihara, Kimio, Hirano, Ryoichi, Takemoto, Akira
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): McNutt, Robert
• Application Number:
  US08/177,466
• Time in Patent Office: 867 Days
• Field of Search: 372/36, 372/34, 372/43, 257/712
• US Class Current: 372/36
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/00011 Not 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/207 Diameter ranges
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements
• CPC Class Codes: H01S 5/02212 Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
• CPC Class Codes: H01S 5/02251 using optical fibres
• CPC Class Codes: H01S 5/0237 by soldering
• CPC Class Codes: H01S 5/024 Arrangements for thermal management

Abstract

A semiconductor light emitting device includes a semiconductor light emitting element mounted on a package stem via a radiating heatsink block, the light emitting point of the light emitting element being positioned on the central axis of the stem and at or near the center of mass of the heatsink block. Another light emitting device includes a light emitting element mounted on a stem via a heatsink block, the light emitting point of the element being positioned on the central axis of the stem with only a portion of a lower surface of the heatsink block close to the central axis of the stem attached to the stem. The movement of the light emitting point with temperature variations is suppressed. Another light emitting device includes a laser chip element mounted on a package stem via a heatsink block, the laser chip element being mounted on the heatsink block so that the emitted light forms an angle θ with a surface of the stem and the position and angle of the emitted light do not vary when the temperature changes.

Claims

1. A semiconductor light emitting device comprising:

a package stem having a central axis;

a radiating heatsink block having a center of mass and mounted on said package stem; and

a semiconductor light emitting element having a light emitting point and mounted on said radiating heatsink block wherein the light emitting point of said semiconductor light emitting element is positioned on the central axis of said package stem and at the center of mass of said radiating heatsink block.

2. A semiconductor light emitting device comprising:

a package stem having a central axis;

a radiating heatsink block having a lower surface and mounted on said package stem; and

a semiconductor light emitting element having a light emitting point and mounted on said radiating heatsink block wherein the light emitting point of said semiconductor light emitting element is positioned on the central axis of said package stem and only a part of the lower surface of said radiating heatsink block close to the central axis of said package stem is attached to said package stem;

3. A semiconductor light emitting device comprising:

a package stem having a central axis.;

a radiating heatsink block mounted on said package stem;

a semiconductor light emitting element having a light emitting point and mounted on said radiating heatsink block wherein the light emitting point of said semiconductor light emitting element is positioned on the central axis of said package stem; and

an expansion restricting stopper comprising a material different from said radiating heatsink block disposed on said package stem in contact with said radiating heatsink block.

4. A semiconductor light emitting device comprising:

a package stem having a surface with a center;

a radiating heatsink block mounted on the surface of said package stem; and

a semiconductor laser chip element having a light emitting point and mounted on said radiating heatsink block wherein light emitted from said semiconductor laser chip element forms an acute angle θ

with the surface of said package stem, wherein a distance from the center of the surface of said package stem measured along the surface to said radiating heatsink block is l1, a height from the center of the surface of said stem to said semiconductor laser chip element along said radiating heatsink block is l2, linear thermal expansion components of said package stem and said radiating heatsink block are α

1 and α

2, respectively, and

space="preserve" listing-type="equation">tanθ

=(l2/l1) and ((l2/l1).sup.2)=(α

1/α

2).

5. A semiconductor light emitting device comprising:

a package stem having a surface with a center;

a radiating heatsink block mounted on the surface of said package stem;

a semiconductor laser chip element having a light emitting point and mounted on said radiating heatsink block wherein light emitted from said semiconductor laser chid element forms an acute angle θ

with the surface of said package stem; and

a submount interposed between said semiconductor laser chip element and said radiating heat sink block wherein positional deviation in light emitted by said semiconductor laser chip element due to different linear thermal expansion lengths of said package stem and said radiating heatsink block is compensated by linear thermal expansion of said submount.

6. The semiconductor light emitting device of claim 5 wherein said submount has a linear thermal expansion coefficient of α

3, a distance from a center of said radiating heatsink block on said submount to an attaching center of said semiconductor laser chip element on said submount is l3, and

space="preserve" listing-type="equation">α

1 l1 sinθ

+α

2·

l2 cosθ

=α

3·

l3.