Light emitting device and method for manufacturing same

• US 9,871,170 B2
• Filed: 06/09/2014
• Issued: 01/16/2018
• Est. Priority Date: 06/18/2013
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Oshima, Yukiko, Sato, Yoshiki, Okazaki, Toshiyuki, Wakaki, Takayoshi
• Primary Examiner(s): Breval, Elmito
• Assistant Examiner(s): Farokhrooz, Fatima
• Application Number:
  US14/299,065
• Publication Number:
  US 20140369052A1
• Time in Patent Office: 1,317 Days
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A light emitting device has a light emitting element, a package, a lead, and a cover film. The package is arranged to form at least part of an inner peripheral face of a recess portion. The light emitting element is housed in the recess portion. The lead is disposed on a bottom face of the recess portion. The lead is electrically connected to the light emitting element. The cover film is arranged to cover the inner peripheral face of the recess portion. The cover film has light transmissive and electrical insulation. The package includes a base material and a plurality of particles. The base material includes a resin. A coefficient of thermal expansion of the particles is different from a coefficient of thermal expansion of the base material. The particles are disposed at least near the inner peripheral face of the recess portion.

Claims

1. A light emitting device comprising:

a light emitting element;

a package arranged to form at least a part of an inner peripheral face of a recess portion, the light emitting element housed in the recess portion, the package including base material and a plurality of particles with each of the particles being at least partially arranged within the base material, the base material including a resin, a coefficient of thermal expansion of the particles being different from a coefficient of thermal expansion of the base material, the particles being disposed at least near the inner peripheral face of the recess portion;

a lead disposed on a bottom face of the recess portion, the lead electrically connected to the light emitting element; and

a cover film arranged to cover the inner peripheral face of the recess portion, the cover film having light transmissive and electrical insulation, the cover film having a plurality of microcracks that penetrate through the cover film and that are generated by the particles tearing the cover film.

2. The light emitting device according to claim 1, wherein

the base material is constituted with an epoxy resin and a filler, and

the particles are constituted with silicone.

3. The light emitting device according to claim 1, wherein

the cover film covers a surface of the lead.

4. The light emitting device according to claim 1, wherein

the cover film includes aluminum oxide or silicon dioxide as major components.

5. The light emitting device according to claim 1, wherein

a spacing between the light emitting element and the inner peripheral face of the package is 2 mm or less.

6. The light emitting device according to claim 1, wherein

a peak wavelength of light emitted from the light emitting element is at least 360 nm and no more than 520 nm.

7. The light emitting device according to claim 1, wherein

a percentage in which the plurality of particles are contained with respect to the package is from 0.5 wt % to 5 wt %.

8. The light emitting device according to claim 1, wherein

an equivalent circle diameter of the plurality of particles is 1 μ

m to 10 μ

m.

9. The light emitting device according to claim 1, wherein

a width of each of the plurality of microcracks is 0.5 μ

m to 30 μ

m.

10. The light emitting device according to claim 1, wherein

a proportion of a surface area of the cover film accounted for by the plurality of microcracks is no more than 5%.

11. The light emitting device according to claim 1, wherein

a portion of the cover film which is disposed on the base material has the plurality of microcracks.

12. The light emitting device according to claim 1, wherein

a frequency of the plurality of microcracks is no more than 6000 microcracks per square millimeter on a surface of the cover film.

13. The light emitting device according to claim 1, wherein

the cover film is disposed on the inner peripheral face of the recess portion and an upper surface of the lead, and the plurality of the microcracks are disposed at the inner peripheral face of the recess portion.

14. The light emitting device according to claim 2, wherein

the filler includes at least one of silicon dioxide and/or titanium dioxide.

15. A light emitting device comprising:

a light emitting element;

a package arranged to form at least a part of an inner peripheral face of a recess portion, the light emitting element housed in the recess portion;

a lead disposed on a bottom face of the recess portion, the lead electrically connected to the light emitting element; and

a cover film arranged to cover the inner peripheral face of the recess portion, the cover film having light transmissive and electrical insulation,

the package including base material and a plurality of particles with each of the particles being at least partially arranged within the base material, the base material including a resin, a coefficient of thermal expansion of the particles being different from a coefficient of thermal expansion of the base material, the particles disposed at least near the inner peripheral face of the recess portion,

the cover film being formed thinner over the particles such that a distance between an upper surface of the particles and an upper surface of a portion of the cover film over the particles is smaller than a distance between an upper surface of the base material and an upper surface of other portion of the cover film.