Color-converting light emitting device including fluorescent powder having large grain diameter, method of producing the same, and resin composition used therein

• US 20050285494A1
• Filed: 10/01/2004
• Published: 12/29/2005
• Est. Priority Date: 06/28/2004
• Status: Abandoned Application

• Current Assignee: Lumimicro Corp. Ltd.
• Original Assignee: Lumimicro Corp. Ltd.
• Inventors: Chung, Won-Young, Kim, Young-Hwan, Kim, Hyun-Min, Cho, Sung-Bin, Oh, Young-Sik
• Application Number:
  US10/956,567
• Publication Number:
  US 20050285494A1
• Time in Patent Office: Days
• US Class Current: 313/112
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

Disclosed is a color-converting light emitting device, which includes a light emitting element for emitting light with a predetermined wavelength and a color-converting member for absorbing a portion of light emitted from the light emitting element to convert the wavelength of the light into another wavelength. The present invention provides the color-converting light emitting device, which includes a gallium nitride-based light emitting diode having an emission spectrum at a visible ray region, and a color-converting member absorbing light from the diode to convert the wavelength of the light into another wavelength. The color-converting member includes a transparent resin and a garnet-based fluorescent powder dispersed in the transparent resin, and the fluorescent powder has a grain size distribution in which a minimum grain diameter is 10 μm or more and a mean grain diameter (d₅₀) is 20 μm or more.

Claims

1. A color-converting light emitting device, which includes a gallium nitride-based light emitting diode, and a color-converting member absorbing light from the light emitting diode to convert a wavelength of the light into another wavelength,

wherein the color-converting member comprises a transparent resin and a garnet-based fluorescent powder dispersed in the transparent resin, and the fluorescent powder has a grain size distribution in which a minimum grain diameter is 10 μ

m or more and a mean grain diameter (d₅₀) is 20 μ

m or more.

3. The color-converting light emitting device as set forth in claim 1 or 2, wherein the garnet-based fluorescent powder is expressed by a compositional formula of A₃B₅O₁₂ and doped by Ce, the A including at least one selected from a group consisting of Y, Lu, Sc, La, Gd, and Sm, the B including at least one selected from a group consisting of Al, Ga, In, and Tb.

4. The color-converting light emitting device as set forth in claim 1 or 2, wherein the grain size distribution of the fluorescent powder forms normal or pseudo-normal distributions.

5. The color-converting light emitting device as set forth in claim 1 or 2, wherein the light emitting diode comprises a light emitting layer made of an InGaN-based compound semiconductor, and has a maximum emission peak within a rang of 430-450 nm.

6. The color-converting light emitting device as set forth in claim 1, wherein the transparent resin comprises a solid resin at room temperature.

7. The color-converting light emitting device as set forth in claim 6, wherein the solid resin includes triglycidyl isocyanurate (TGIC).

9. The color-converting light emitting device as set forth in claim 1 or 2, wherein the mean grain diameter of the fluorescent powder is 50 μ

m or less.

2. A color-converting light emitting device, which includes a gallium nitride-based light emitting diode, and a color-converting member absorbing light from the light emitting diode to convert a wavelength of the light into another wavelength,

wherein the color-converting member comprises a transparent resin and a garnet-based fluorescent powder dispersed in the transparent resin, the transparent resin comprises solid and liquid resins at room temperature, a content of the solid resin is 40-60 wt % based on a weight of the transparent resin, and the fluorescent powder has a grain size distribution in which a mean grain diameter (d₅₀) is 20 μ

m or more.

8. The color-converting light emitting device as set forth in claim 2, wherein the solid resin includes triglycidyl isocyanurate (TGIC).

15. The epoxy resin casting composition as set forth in claim 8, wherein the transparent resin includes at least one selected from a group consisting of cyclohexene epoxide derivative, bisphenol A hydride diglycidyl ether, and hexahydrophthalic acid glycidyl ether.

10. An epoxy resin casting composition for a color-converting light emitting element, comprising:

a transparent resin including solid and liquid resins and having a viscosity of 4000-9000 cps; and

an YAG-based fluorescent powder dispersed in the transparent resin and having a mean grain diameter (d₅₀) of 20 μ

m or more.

11. The epoxy resin casting composition as set forth in claim 10, wherein the viscosity of the transparent resin is 7000 cps or more.

12. The epoxy resin casting composition as set forth in claim 10, wherein the mean grain diameter of the YAG-based fluorescent powder is 50 μ

m or less.

13. The epoxy resin casting composition as set forth in claim 10, wherein the transparent resin includes a solid resin consisting of triglycidyl isocyanurate (TGIC).

14. The epoxy resin casting composition as set forth in claim 10, wherein the transparent resin is partially hardened.

16. A method of producing a color-converting light emitting device, comprising:

providing a transparent resin including a solid resin;

partially hardening the transparent resin;

mixing the transparent resin with a garnet-based fluorescent powder having a mean grain diameter of 20 μ

m or more to provide an epoxy resin composition for the color-converting light emitting device;

applying the transparent resin composition onto a gallium nitride-based semiconductor diode chip; and

completely hardening the resulting transparent resin composition.

17. The method as set forth in claim 16, wherein the partial hardening is conducted through a heat hardening process.