IC Chip Coating Material and Vacuum Fluorescent Display Device Using Same

Abstract

An IC chip coating material includes first metal oxide particles; a metal alkoxide; an organic solvent; and second metal oxide particles and/or flat particles of a composite oxide, the second metal oxide particles having a composition identical to or different from that of the first metal oxide particles and also having a mean particle size and/or a shape different from that of the first metal oxide particles. Further, a vacuum fluorescent display device includes an IC chip, wherein the IC chip is at least partially coated by a coating material layer including the first metal oxide particles; a metal forming metal alkoxide; and the second metal oxide particles and/or flat particles of a composite oxide.

1 . A vacuum fluorescent display device comprising:
 an IC chip,   wherein the IC chip is at least partially coated by a coating material layer which includes:
 first metal oxide particles for coloring the coating material layer, the first metal oxide particles including particles of alumina; 
 second metal oxide particles serving as a fixing material, the second metal oxide particles being formed from an alumina-based metal alkoxide; and 
 flat composite oxide particles including particles of mica, wherein the first metal oxide particles have a mean particle size different from that of the second metal oxide particles. 
   
     
     
         2 . The vacuum fluorescent display device of  claim 1 , wherein the coating material layer for coating the IC chip is white. 
     
     
         3 . The vacuum fluorescent display device of  claim 1 , wherein the first and second metal oxide particles consist of alumina. 
     
     
         4 . The vacuum fluorescent display device of  claim 1 , wherein the flat composite oxide particles consist of the particles of the mica. 
     
     
         5 . The vacuum fluorescent display device of  claim 1 , wherein the mean particle size of the first metal oxide particles is about 0.3 μm. 
     
     
         6 . The vacuum fluorescent display device of  claim 1 , wherein a mean particle size of the flat composite oxide particles is about 25 μm. 
     
     
         7 . The vacuum fluorescent display device of  claim 1 , wherein the first metal oxide particles have a shape different from that of the second metal oxide particles. 
     
     
         8 . The vacuum fluorescent display device of  claim 1 , wherein a mean particle size of the flat composite oxide particles is different from these of the first and the second metal oxide particles. 
     
     
         9 . The vacuum fluorescent display device of  claim 1 , wherein the flat composite oxide particles have a shape different from these of the first and the second metal oxide particles. 
     
     
         10 . The vacuum fluorescent display device of  claim 1 , wherein the flat composite oxide particles serve to reduce a stress of the coating material layer due to a thermal expansion when the coating material layer is formed. 
     
     
         11 . The vacuum fluorescent display device of  claim 1 , wherein the flat composite oxide particles serve to reduce an elasticity of the coating material layer. 
     
     
         12 . The vacuum fluorescent display device of  claim 1 , wherein the coating material layer serves as a layer protecting the IC chip from the surroundings thereof. 
     
     
         13 . The vacuum fluorescent display device of  claim 1 , further comprising: one or more bonding wires each of which is connected to an electrode of the IC chip. 
     
     
         14 . The vacuum fluorescent display device of  claim 3 , wherein the flat composite oxide particles consist of the particles of the mica. 
     
     
         15 . The vacuum fluorescent display device of  claim 7 , wherein a mean particle size of the flat composite oxide particles is different from these of the first and the second metal oxide particles. 
     
     
         16 . The vacuum fluorescent display device of  claim 8 , wherein the flat composite oxide particles have a shape different from these of the first and the second metal oxide particles. 
     
     
         17 . The vacuum fluorescent display device of  claim 9 , wherein the IC chip and the bonding wires are entirely coated by the coating material layer. 
     
     
         18 . The vacuum fluorescent display device of  claim 15 , wherein the flat composite oxide particles have a shape different from these of the first and the second metal oxide particles. 
     
     
         19 . The vacuum fluorescent display device of  claim 1 , wherein a mean particle size ratio of the first metal oxide particles to the flat composite oxide particles is set to be 1:5 or more. 
     
     
         20 . The vacuum fluorescent display device of  claim 1 , wherein an amount of the flat composite oxide particles is about 20% of a total amount of the first metal oxide particles and the flat composite oxide particles in the coating material layer.