Method of forming phosphor film and method of manufacturing light emitting diode package incorporating the same

Abstract

The invention relates to a method of forming a phosphor film and a method of manufacturing an LED package incorporating the same. The method of forming a phosphor film includes mixing phosphor and light-transmitting beads in an aqueous solvent such that the nano-sized light-transmitting beads having a first charge are adsorbed onto surfaces of phosphor particles having a second charge. The method also includes coating a phosphor mixture obtained from the mixing step on an area where the phosphor film is to be formed, and drying the coated phosphor mixture to form the phosphor film. The invention further provides a method of manufacturing an LED package incorporating the method of forming the phosphor film.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart showing a method of forming a phosphor film according to the present invention;

FIG. 2 is a schematic view illustrating the operation of nano-beads in the phosphor film formed according to the present invention;

FIG. 3 is a schematic view illustrating a light emitting diode package with the phosphor film formed therein according to the present invention;

FIG. 4 is a Scanning Electron Microscope (SEM) picture of polystyrene nano-beads adopted in an embodiment of the present invention;

FIGS. 5 a and 5b are SEM pictures showing phosphor particles with nano-beads adsorbed thereon before and after drying (phosphor mixture and phosphor film) according to an embodiment of the present invention; and

FIG. 6 is a graph illustrating luminance enhancement effect of a light emitting diode package manufactured according to an embodiment of the present invention.

Claims

1. A method of forming a phosphor film comprising steps of: Mixing phosphor and light-transmitting beads in an aqueous solvent such that the nano-sized light-transmitting beads having a first charge are adsorbed onto surfaces of phosphor particles having a second charge;Coating a phosphor mixture obtained from the mixing step on an area where the phosphor film is to be formed; andDrying the coated phosphor mixture to form the phosphor film.

2. The method according to claim 1, wherein the mixing step comprises adding and mixing a dispersing agent having a first charge together with the phosphor and the light-transmitting beads.

3. The method according to claim 1, wherein each of the light-transmitting nano-beads has a mean diameter of 50 nm to 500 nm.

4. The method according to claim 1, wherein the light-transmitting nano-beads have a glass transition temperature of at least 100° C.

5. The method according to claim 1, wherein the phosphor particles have a positive charge, and each of the light-transmitting nano-beads has a functional group having a negative charge on a surface thereof, selected from a group consisting of sulfonates, phosphates and carboxylates.

6. The method according to claim 1, wherein each of the light-transmitting nano-beads comprises one selected from a group consisting of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephtalate (PET), polyethylene naphthalate (PEN), polybutylene terephtalate (PBT), polyethersulfone (PES), polyetherketone (PEEK), polycarbonate (PC), polyimide (PI), polyetherimide and polyacrylate.

7. The method according to claim 1, wherein the phosphor comprises 2 wt % to 10 wt % of the aqueous solvent.

8. The method according to claim 1 or 7, wherein the light-transmitting nano-beads comprise 5 wt % to 10 wt % with respect to the weight of the phosphor mixed.

9. The method according to claim 1, wherein the aqueous solvent comprises deionized water or alcohol.

10. A method of manufacturing a light emitting diode package, comprising steps of: mixing phosphor and light-transmitting beads in an aqueous solvent such that the nano-sized light-transmitting beads having a first charge are adsorbed onto surfaces of the phosphor particles having a second charge;coating a phosphor mixture obtained from the mixing step on at least a light emitting surface portion of a light emitting diode chip;drying the coated phosphor mixture to form a phosphor film; andforming a resin part on the light emitting diode chip with the phosphor film formed thereon.

11. The method according to claim 10, wherein the mixing step comprises adding and mixing a dispersing agent having a first charge together with the phosphor and the light-transmitting beads.

12. The method according to claim 10, wherein each of the light-transmitting nano-beads has a mean diameter of 50 to 50 nm.

13. The method according to claim 10, wherein each of the light-transmitting nano-beads has a glass transition temperature of at least 100° C.

14. The method according to claim 10, wherein the light-transmitting nano-beads has a refractive index higher than that of the light emitting diode and lower than that of the resin part.

15. The method according to claim 10, wherein the phosphor particles have a positive charge, and the each of the light-transmitting nano-beads has a functional group having a negative charge selected from a group consisting of sulfonates, phosphates and carboxylates on a surface thereof.

16. The method according to claim 10, wherein each of the light-transmitting nano-beads comprises one selected from a group consisting of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephtalate (PET), polyethylene naphthalate (PEN), polybutylene terephtalate (PBT), polyethersulfone (PES), polyetherketone (PEEK), polycarbonate (PC), polyimide (PI), polyetherimide and polyacrylate.

17. The method according to claim 10, wherein the phosphor is mixed in the amount of 2 wt % to 20 wt % of the aqueous solvent.

18. The method according to claim 10 or 17, wherein the light-transmitting nano-beads are mixed in the amount of 5 wt % to 40 wt % with respect to the weight of the phosphor mixed.

19. The method according to claim 10, wherein the aqueous solvent comprises deionized water or alcohol.