Patent ID: 6242852
Filing Date: 2001-06-05
Classification: H01J

Abstract:
An electron gun comprising:a heater built-in inner sleeve having provided at a leading end thereof an impregnated type cathode, wherein an outside diameter of said heater built-in inner sleeve is in a range of substantially 1.0 mm to 1.2 mm;an outer sleeve in which said heater built-in inner sleeve is inserted; anda plurality of strap-like supporting members attached at first ends thereof at a respective plurality of positions spaced at regular intervals in a peripheral direction to a leading end of said outer sleeve and attached at second ends thereof to a base end of said inner sleeve opposite said leading end, such that said heater built-in inner sleeve is disposed coaxially with said outer sleeve, said impregnated type cathode is positioned at the leading end of said outer sleeve, and said heater built-in inner sleeve is separated from said outer sleeve by an annular space therebetween,wherein said outer sleeve has on the leading end a small-diameter portion having a diameter smaller than a diameter of the remaining portion of said outer sleeve on a base end,said heater built-in inner sleeve is positioned in said small-diameter portion, andthe leading end of said small-diameter portion of said outer sleeve is connected to the base end of said inner sleeve by said plurality of strap-like connecting members.