Light-emitting device and manufacturing method thereof

• US 7,812,516 B2
• Filed: 11/28/2007
• Issued: 10/12/2010
• Est. Priority Date: 11/28/2006
• Status: Expired due to Fees

• Current Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited)
• Original Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited)
• Inventors: Maruyama, Tsukasa, Ikuta, Tetsuya
• Primary Examiner(s): Patel; Ashok
• Application Number:
  US11/987,176
• Publication Number:
  US 20080122343A1
• Time in Patent Office: 1,049 Days
• Field of Search: None
• US Class Current: 313/503
• CPC Class Codes: H01J 1/63 characterised by the luminescent material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A light-emitting device includes: a light-emitting element whose main emission wavelength is 410 nm or less; and one phosphor layer or more stacked to cover a light-emitting surface of the light-emitting element and containing phosphors that absorb light from the light-emitting element and wavelength-convert the absorbed light to emit light.

Claims

1. A light-emitting device comprising:

a light-emitting element whose main emission wavelength is 410 nm or less; and

one phosphor layer or more stacked directly on a light-emitting surface of said light-emitting element and containing phosphors that absorb light from said light-emitting element and wavelength-convert the absorbed light to emit light,

wherein said phosphor layer is composed of two or more stacked phosphor forming layers in each of which the phosphors are disposed on an adhesive whose thickness is equal to or less than an average particle size of the phosphors, and

wherein a difference between a maximum thickness and a minimum thickness of said phosphor layer is equal to or less than two times an average particle size of the phosphors, and an occupancy ratio of the phosphors in said phosphor layer is 50% or more.

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

wherein said phosphor layer is composed of a plurality of phosphor layers containing different phosphors, and the difference between the maximum thickness and the minimum thickness of the phosphor layer closest to said light-emitting element, among said plural phosphor layers, is equal to or less than two times the average particle size of the phosphors contained in the phosphor layer closest to said light-emitting element.

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

wherein a thickness of said phosphor layer is equal to or less than five times the average particle size of the phosphors.

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

wherein said phosphor layer is stacked in two layers or more on the light-emitting surface of said light-emitting element, and

wherein a main emission wavelength of the phosphors contained in the phosphor layer closest to said light-emitting element is different from a main absorption wavelength of the phosphors contained in the phosphor layer farthest from said light-emitting element.

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

wherein the occupancy ratio of the phosphors in the phosphor forming layer farthest from said light-emitting element, among the two or more phosphor forming layers, is 50% or less and an occupancy ratio of the phosphors in the other phosphor forming layers is 60% or more.

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

wherein the phosphors have an adjusted particle size.