Electron source substrate with low sodium upper surface

A sodium containing substrate for carrying an electron-emitting device on the surface thereof, wherein (i) the sodium concentration of said substrate is reduced in the vicinity of a surface for carrying an electron-emitting device as compared to the bulk body of said substrate, and (ii) a layer with a composition such that sodium is partially replaced by potassium as compared to the composition of the bulk body of said substrate is formed to constitute the surface for carrying the electron-emitting device.

An electron source comprising a substrate and an electron-emitting device arranged on the surface of said substrate, wherein said substrate contains (i) sodium with the sodium concentration of said substrate being reduced in the vicinity of a surface carrying said electron-emitting device as compared to the bulk body of said substrate, and (ii) sulfur with a layer having a sulfur concentration smaller than that of the bulk body of said substrate being formed to a depth greater that 0.01 μm from the surface carrying said electron-emitting device, the sulfur concentration of the laver being not greater than 0.1%.

An electron source comprising a substrate and an electron-emitting device arranged on a surface of said substrate, wherein (i) said substrate contains sodium and the sodium concentration of said substrate is reduced in the vicinity of the surface carrying said electron-emitting device as compared to the bulk body of said substrate, and (ii) a layer with a composition such that sodium is partially replaced by potassium as compared to the composition of the bulk body of said substrate is formed to constitute the surface carrying said electron-emitting device.

An image-forming apparatus comprising a substrate, electron-emitting devices arranged on a surface of said substrate and an image forming member for forming images as irradiated with electrons emitted from said electron-emitting devices, wherein said substrate contains (i) sodium with the sodium concentration of the substrate being reduced in the vicinity of the surface carrying said electron-emitting devices as compared to the bulk body of said substrate, and (ii) sulfur with a layer having a sulfur concentration smaller than that of the bulk body of the substrate being formed to a depth greater than 0.01 μm from the surface carrying said electron-emitting devices, the sulfur concentration of the layer being not greater than 0.1%.

An image-forming apparatus comprising a substrate, electron-emitting devices arranged on a surface of said substrate and an image forming member for forming images as irradiated with electrons emitted from said electron-emitting devices, wherein (i) said substrate contains sodium with the sodium concentration of said substrate being reduced in the vicinity of the surface carrying said electron-emitting devices as compared to the bulk body of said substrate, and (ii) a layer with a composition such that sodium is partially replaced by potassium as compared to the composition of the bulk body of said substrate is formed to constitute the surface carrying said electron-emitting devices.