Electron source substrate, production method thereof, and image forming apparatus using electron source substrate

Abstract

An electron source substrate has an electron-emitting device consisting of a pair of device electrodes and an electroconductive thin film having an electron-emitting region; and metal wiring coupled to the device electrodes and made in a composition different from that of the device electrodes, on a substrate. A shortest distance between the conductive thin film and the metal wiring along an interface between the device electrodes and the substrate is not less than 50 μm. This configuration is able to effectively prevent diffusion of the wiring metal to the conductive thin film and to the electron-emitting region which can cause degradation of electron emission characteristics.

1. An electron source substrate comprising an electron-emitting device consisting of a pair of device electrodes and an electroconductive thin film having an electron-emitting region; and metal wiring coupled to the device electrodes and made in a composition different from that of the device electrodes, on a substrate, wherein a shortest distance between the conductive thin film and the metal wiring along an interface between the device electrodes and the substrate is not less than 50 μm. 
     
     
       2. The electron source substrate according to  claim 1 , wherein said shortest distance is not less than 100 μm. 
     
     
       3. An electron source substrate comprising an electron-emitting device consisting of  having a pair of device electrodes and an electroconductive thin film having  an electron-emitting region  member connected to said pair of device electrodes; and metal wiring coupled to the device electrodes and made in a composition different from that of the device electrodes, on a substrate, wherein the metal wiring includes at least one X- directional wire and at least one Y - directional wire which intersect each other, one of the device electrodes is connected to the X - directional wire and another of the device electrodes is connected to the Y - directional wire, at least one of said pair of device electrodes is defined in shape so that  a path with a shortest distance between the conductive thin film  electron- emitting member  and the metal wiring along an interface between the device electrodes  said at least one device electrode and the substrate is comprised of a combination of straight or curved lines forming an angle. 
     
     
       4. The electron source substrate according to  claim 3 , wherein a region on a linear shortest path between said conductive thin film  electron- emitting member  and said metal wiring has an area without a device electrode. 
     
     
       5. The electron source substrate according to  claim 1  or  3 , wherein said device electrodes are comprised of a metal material containing at least a platinum material. 
     
     
       6. The electron source substrate according to  claim 1  or  3 , wherein said substrate is comprised of a sodium-containing glass base and a sodium diffusion preventing layer formed on the glass base. 
     
     
       7. The electron source substrate according to  claim 6 , wherein
 said sodium-containing glass base is comprised of soda lime glass.  
 
     
     
       8. The electron source substrate according to  claim 6 , wherein said sodium diffusion preventing layer is comprised of a silica film 500 nm or more thick. 
     
     
       9. The electron source substrate according to  claim 8 , wherein said silica film is a phosphorus-doped silica film. 
     
     
       10. The electron source substrate according to  claim 6 , wherein said sodium diffusion preventing layer is comprised of a film 200 nm or more thick containing an electroconductive oxide, and a silica film 80 nm or more thick formed on said film and containing a main component of silica. 
     
     
       11. The electron source substrate according to  claim 10 , wherein said film containing the electroconductive oxide is a microparticle film containing a main component of tin oxide doped with phosphorus. 
     
     
       12. The electron source substrate according to  claim 1  or  3 , wherein said metal wiring is comprised of a metal selected from Ag, Cu, Al, and Au, or an alloy containing said metal. 
     
     
       13. The electron source substrate according to  claim 1  or  3  , wherein said electroconductive thin film having the electron-emitting region is comprised of Pd or PdO, or a mixture thereof. 
     
     
       14. The electron source substrate according to  claim 1  or  3 , wherein said electron-emitting device is a surface conduction electron-emitting device. 
     
     
       15. The electron source substrate according to  claim 1  or  3  , wherein said metal wiring is comprised of a plurality of X-directional wires and a plurality of Y-directional wires and wherein a plurality of electron-emitting devices are matrix-wired by the X-directional wires and the Y-directional wires. 
     
     
       16. A method of producing the electron source substrate as set forth in  claim 1  or  3 , wherein said metal wiring is formed by printing and heat baking of a metal paste. 
     
     
       17. An electron source substrate comprising an electron-emitting device having a pair of device electrodes and an electron-emitting region between the device electrodes  member connected to at least one of said pair of device electrodes; and metal wiring coupled to the device electrodes and made in a composition different from that of the device electrodes, on a substrate, wherein the metal wiring includes at least one X- directional wire and at least one Y - directional wire which intersect each other, one of the device electrodes is connected to the X - directional wire and another of the device electrodes is connected to the Y - directional wire, at least one of said pair of device electrodes is defined in shape so that  a path with a shortest distance between said electron-emitting region  member and said metal wiring electrically coupled to the electron-emitting region  member along an interface between said at least one device electrodes  electrode and said substrate is comprised of a combination of straight or curved lines forming an angle. 
     
     
       18. An image forming apparatus for forming an image on the basis of an input signal, comprising at least an image forming member and the electron source substrate as set forth in one of  claim 1 ,  3 , or  17 . 
     
     
       19. The electron source substrate according to  claim 3 , wherein
 at least one of the straight or curved lines, of which the path with the shortest distance is comprised, has a length in a thickness direction of the substrate.  
 
     
     
       20. The electron source substrate according to  claim 17 , wherein
 at least one of the straight or curved lines, of which the path with the shortest distance is comprised, has a length in a thickness direction of the substrate.  
 
     
     
       21. The electron source substrate according to  claim 3 , wherein
 at least one of the straight or curved lines, of which the path with the shortest distance is comprised, has a length in a direction in parallel to a surface of the substrate.  
 
     
     
       22. The electron source substrate according to  claim 17 , wherein
 at least one of the straight or curved lines, of which the path with the shortest distance is comprised, has a length in a direction in parallel to a surface of the substrate.  
 
     
     
       23. An electron source substrate comprising an electron- emitting device consisting of a pair of device electrodes and an electron - emitting member connected to said pair of device electrodes; and metal wiring coupled to the device electrodes and made in a composition different from that of the device electrodes, on a substrate, wherein the wiring includes at least one X - directional wire and at least one Y - directional wire which intersect each other, one of the device electrodes is connected to the X - directional wire and another of the device electrodes is connected to the Y - directional wire, at least one of said pair of device electrodes is defined in shape so that a linear shortest path between the electron emitting member and at least one of the X - directional and Y - directional wires traverses at least part of one device electrode and an area on the substrate where any part of said at least one device electrode is not defined.   
     
     
       24. An electron source substrate according to any one of claims  3 ,  17 , and  23 , wherein at least one of the device electrodes forms an L- shape.