Luminescent layer and light-emitting semiconductor device

Abstract

A chip-type light-emitting semiconductor device includes: a substrate 4; a blue LED 1 mounted on the substrate 4; and a luminescent layer 3 made of a mixture of yellow/yellowish phosphor particles 2 and a base material 13 (translucent resin). The yellow/yellowish phosphor particles 2 is a silicate phosphor which absorbs blue light emitted by the blue LED 1 to emit a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, inclusive, and which contains, as a main component, a compound expressed by the chemical formula: (Sr 1-a1-b1-x Ba a1 Ca b1 Eu x ) 2 SiO 4 (0≤a1≤0.3, 0≤b1≤0.8 and 0<x<1). The silicate phosphor particles disperse substantially evenly in the resin easily. As a result, excellent white light is obtained.

The invention claimed is: 
     
       1. A luminescent layer comprising phosphor particles, ultra-fine particles and a translucent resin,
 wherein the phosphor particles are dispersed within the translucent resin and primary particles of the ultra-fine particles have an average particle size in the range from 3 nm to 50 nm, both inclusive.   
     
     
       2. The luminescent layer of  claim 1 , wherein the ultra-fine particles are thixotropy improvers. 
     
     
       3. The luminescent layer of  claim 1 , wherein the ultra-fine particles include silicon dioxide and/or aluminum oxide. 
     
     
       4. The luminescent layer of  claim 1 , wherein the resin is any one of an epoxy resin, an acrylic resin, a polyimide resin, a urea resin or a silicone resin. 
     
     
       5. The luminescent layer of  claim 1 , wherein the phosphor particles have a core particle size in the range from 0.5 μm to 30 μm, both inclusive. 
     
     
       6. The luminescent layer of  claim 5 , wherein the phosphor particles have a core particle size in the range from 1 μm to 20 μm, both inclusive. 
     
     
       7. The luminescent layer of  claim 1 , wherein the phosphor particles are silicate phosphor particles. 
     
     
       8. The luminescent layer of  claim 1 , wherein the luminescent layer is formed by any one of a photolithography process, a screen-printing process or a transfer process. 
     
     
       9. A light-emitting semiconductor device utilizing the, comprising:
 a luminescent layer of  claim 1  and including:
 phosphor particles; 
 ultra-fine particles including primary particles, the primary particles having an average particle size of equal to or greater than 3 nm and equal or less than 50 nm; and 
 a translucent resin; 
 
 a light-emitting device in combination,; and 
 a supporter, wherein: 
 the phosphor particles are dispersed in the translucent resin, 
 the light-emitting device is disposed on the supporter, 
 the light-emitting device has a bottom surface facing the supporter, and a main light-extracting surface from which a light is extracted and opposite to the bottom surface, 
 the luminescent layer is in contact with the light-emitting device only at the main light-extracting surface, 
 the luminescent layer covers an entirety of the main light-extracting surface, and extends beyond outer edges of the light-emitting device, and 
 the light-emitting semiconductor device emits mixed light mixed with from light emitted from the light-emitting device and a fluorescence emitted from the phosphor particles. 
 
     
     
       10. The light-emitting semiconductor device of  claim 9 , wherein the light emitted from the light-emitting device has a main emission peak in the a wavelength range greater than 430 nm and less than or equal to 500 nm, and the phosphor particles emit the fluorescence having a main emission peak in a wavelength range equal to or greater than 550 nm and equal to or less than 600 nm. 
     
     
       11. The light-emitting semiconductor device of  claim 10 , wherein the phosphor emits a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive. 
     
     
       12. The light-emitting semiconductor device of  claim 9 , wherein the phosphor emits a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive. 
     
     
       13. The light-emitting semiconductor device of  claim 9 , wherein the light-emitting semiconductor device has a plurality of LEDs light-emitting devices, and the luminescent layer continuously covers the plurality of LEDs light-emitting devices. 
     
     
       14. The light-emitting semiconductor device of claim  13  9, wherein a portion of an upper surface of a portion of the luminescent layer is flat and substantially parallel to the main light extracting surface, and when viewed in plan, the portion of the upper surface is located on a light-extracting surface of inside the outer edges of the light-emitting device is flat and substantially parallel to the light-extracting surface. 
     
     
       15. The luminescent layer of  claim 1  light-emitting semiconductor device of claim 9, wherein the ultra-fine particles have a concentration of 1.11% or more. 
     
     
       16. The luminescent layer of  claim 1 , wherein the resin is a silicone resin. 
     
     
       17. The luminescent layer of  claim 16 , wherein the ultra-fine particles include at least one of silicon dioxide and aluminum oxide. 
     
     
       18. The luminescent layer of  claim 1 , wherein the luminescent layer is formed by a screen-printing process. 
     
     
       19. The luminescent layer of  claim 1 , wherein the luminescent layer has a substantial thickness larger than 50 μm. 
     
     
       20. The luminescent layer of  claim 19  light-emitting semiconductor device of claim 9, wherein: 
 the ultra-fine particles include at least one of silicone silicon dioxide and aluminum oxide, 
 the translucent resin is a silicon silicone resin, and 
 the luminescent layer has a substantial thickness in the range from equal to or greater than 50 μm to and equal to or less than 1000 μm both inclusive. 
 
     
     
       21. The luminescent layer of  claim 1  light-emitting semiconductor device of claim 9, wherein the absolute specific gravity of the phosphor particles is greater than or equal to 3.0. 
     
     
       22. The luminescent layer of  claim 1 , wherein the ultra-fine particles are dispersed within the translucent resin. 
     
     
       23. The light-emitting semiconductor device of claim 9, wherein a thickness of the luminescent layer is equal to or greater than 100 μm and equal to or less than 700 μm. 
     
     
       24. The light-emitting semiconductor device of claim 9, wherein, when viewed in plan, a part of the supporter is exposed from the luminescent layer. 
     
     
       25. The light-emitting semiconductor device of claim 24, wherein the supporter covers a side surface of the luminescent layer. 
     
     
       26. The light-emitting semiconductor device of claim 9, wherein a space is formed between the supporter, the light-emitting device and the luminescent layer.