Laser diode chip on printed circuit board

• US 10,257,932 B2
• Filed: 02/16/2016
• Issued: 04/09/2019
• Est. Priority Date: 02/16/2016
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Mandelboum, David, Felzenshtein, Shlomo, Shem-Tov, Boaz, Price, Raymond Kirk, Nalla, Ravi Kiran
• Primary Examiner(s): Chen, Xiaoliang
• Application Number:
  US15/044,526
• Publication Number:
  US 20170238420A1
• Time in Patent Office: 1,148 Days
• Field of Search: 174260, 174252, 174262, 372 34, 372 36, 257 99, 257722, 257728
• CPC Class Codes: F21V 19/0015 Fastening arrangements intended to retain light sources
• CPC Class Codes: F21Y 2115/30 Semiconductor lasers
• CPC Class Codes: G03B 15/03 Combinations of cameras with lighting apparatus; Flash units
• CPC Class Codes: H05K 1/0206 by printed thermal vias
• CPC Class Codes: H05K 1/0207 using internal conductor planes parallel to the surface for thermal conduction, e.g. power planes
• CPC Class Codes: H05K 1/0298 Multilayer circuits
• CPC Class Codes: H05K 1/115 Via connections; Lands around holes or via connections H05K1/112 takes precedence
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/09536 Buried plated through-holes, i.e. plated through-holes formed in a core before lamination
• CPC Class Codes: H05K 2201/10121 Optical component, e.g. opto-electronic component
• CPC Class Codes: H05K 2203/049 Wire bonding
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: H05K 3/321 by conductive adhesives
• CPC Class Codes: H05K 3/4602 characterized by a special circuit board as base or central core whereon additional circuit layers are built or additional circuit boards are laminated
• CPC Class Codes: H05K 3/4608 comprising an electrically conductive base or core
• CPC Class Codes: H05K 3/4617 characterized by laminating only or mainly similar single-sided circuit boards
• CPC Class Codes: H05K 3/4644 by building the multilayer layer by layer, i.e. build-up multilayer circuits making via holes in the insulating layers H05K3/0011; special circuit boards as base or core whereon the multilayer is built H05K3/4602
• CPC Class Codes: H05K 3/4652 Adding a circuit layer by laminating a metal foil or a preformed metal foil pattern H05K3/4647 takes precedence
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A light source module comprising a semiconductor light source mounted directly to a conducting trace of a multilayer printed circuit board having a core comprising a plurality of core layers electrically and thermally coupled by a plurality of buried vias wherein at least one of the core layers comprises a heat sink plane.

Claims

1. A light source module comprising:

a multilayer printed circuit board (ML-PCB) having;

a core comprising a plurality of core layers electrically and thermally coupled by a plurality of buried vias wherein at least one of the plurality of core layers comprises a heat sink plane;

a top layer on a first side of the core having formed thereon a first conducting element and second and third conducting elements respectively on either side of the first conducting element, wherein each of the first, second, and third conducting elements is thermally coupled to the heat sink plane of the at least one of the plurality of core layers by a plurality of microvias;

a bottom layer on a second side of the core opposite the first side; and

a semiconducting light source having a first electrode bonded to the first conducting element with a thermally and electrically conducting epoxy and electrically connected to each of the second and third electrodes by a plurality of bond wires.

2. The light source module according to claim 1 wherein a second core layer of the plurality of core layers comprises a second heat sink plane and wherein the heat sink plane and the second heat sink plane are thermally coupled by the plurality of buried vias.

3. The light source module according to claim 2 wherein the plurality of buried vias are arrayed at a pitch less than or equal to about 500 μ

m.

4. The light source module according to claim 2 wherein the at least one of the plurality of core layers and the second core layer of the plurality of core layers comprises all of the plurality of core layers.

5. The light source module according to claim 1 wherein the plurality of microvias that couple the first conducting element to the heat sink plane of the at least one of the plurality of core layers are distributed in array having a pitch less than or equal to about 400 μ

m in an area of the first conducting element to which the first electrode of the semiconducting light source is bonded.

6. The light source module according to claim 5 wherein the pitch is less than or equal to about 300 μ

m.

7. The light source module according to claim 6 wherein the pitch is less than or equal to about 250 μ

m.

8. The light source module according to claim 1 wherein the plurality of bond wires have a length less than about 1.0 mm.

9. The light source module according to claim 1 wherein the plurality of bond wires have a length less than about 600 μ

m.

10. The light source module according to claim 1 wherein the electrically conducting epoxy is characterized by thermal conductivity greater than or equal to about 10 W/m-K (watts per meter-degree Kelvin).

11. The light source module according to claim 1 wherein the core comprises at least four core layers, each of which comprises a heat sink plane.

12. The light source module according to claim 11 wherein the ML-PCB has a 2-4-2 stack-up structure.

13. The light source module according to claim 1 characterized by a thermal relaxation time that is less than or equal to about 1 second.

14. The light source module according to claim 1, further comprising a light source driver electrically connected to the first, second, and third conducting elements that generates current flow to or from the semiconducting light source via the first conducting element and respectively from or to the semiconducting light source via the second and third conducting elements to control emission of light by the semiconducting light source.

15. The light source module according to claim 14 wherein inductance of electrical connections of the light source driver to the first, second, and third conducting elements and electrical connections of the first, second, and third conducting elements to the semiconducting light source is less than or equal to about 1 nanohenries (nH).

16. A camera comprising:

a memory; and

a light source component comprising;

a multilayer printed circuit board (ML-PCB) comprising;

a core comprising a plurality of core layers electrically and thermally coupled by a plurality of buried vias wherein at least one of the plurality of core layers comprises a heat sink plane;

a top layer on a first side of the core having formed thereon a first conducting element and second and third conducting elements respectively on either side of the first conducting element, wherein each of the first, second, and third conducting elements is thermally coupled to the heat sink plane of the at least one of the plurality of core layers by a plurality of microvias;

a bottom layer on a second side of the core opposite the first side; and

a semiconducting light source having a first electrode bonded to the first conducting element with a thermally and electrically conducting epoxy and electrically connected to each of the second and third electrodes by a plurality of bond wires.

17. The camera according to claim 16, further comprising a controller configured to control the light source component to transmit light to illuminate a scene.

18. The camera according to claim 16, wherein a second core layer of the plurality of core layers comprises a second heat sink plane and wherein the heat sink plane and the second heat sink plane are thermally coupled by the plurality of buried vias.

19. The camera according to claim 16, wherein the plurality of microvias that couple the first conducting element to the heat sink plane of the at least one of the plurality of core layers are distributed in array having a pitch less than or equal to about 400 μ

m in an area of the first conducting element to which the first electrode of the semiconducting light source is bonded.

20. A system comprising:

a memory; and

a camera comprising a light source component, the light source component comprising;

a multilayer printed circuit board (ML-PCB) comprising;

a core comprising a plurality of core layers electrically and thermally coupled by a plurality of buried vias wherein at least one of the plurality of core layers comprises a heat sink plane;

a top layer on a first side of the core having formed thereon a first conducting element and second and third conducting elements respectively on either side of the first conducting element, wherein each of the first, second, and third conducting elements is thermally coupled to the heat sink plane of the at least one of the plurality of core layers by a plurality of microvias;

a bottom layer on a second side of the core opposite the first side; and

a semiconducting light source having a first electrode bonded to the first conducting element with a thermally and electrically conducting epoxy and electrically connected to each of the second and third electrodes by a plurality of bond wires.