Apparatus and method for providing electron beam patterns using expanded beam array
AssigneeInternational Business Machines Corporation
InventorVernon D. Beck
Life of this patent
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Abstract
An apparatus and method for forming scanned electron beam patterns which finds particular use in multiple beam cathode ray tubes. Instead of using the vertical line array of electron beam sources which is used in conventional multiple beam tubes, a two dimensional expanded beam array is provided. The expanded array is such that no two electron beams in the array are disposed in the same scan line and it is of a geometric shape having comparable length and width dimensions. In order to form characters or other patterns logic circuitry is provided to control each beam of the expanded array at respective scanning positions as the array is deflected or scanned across the screen of the cathode ray tube.
Claims16
An apparatus for forming a scanned electron beam pattern which substantially avoids or reduces mutual beam repulsion, beam intermodulation, and grid mounting problems, comprising:
- electron beam emitter means (40, 42) for emitting a plurality of electron beams which are disposed in relation to each other so as to form an array of beams,
- means for deflecting (72) each of said beams through a plurality of spaced apart, parallel scan lines, each said scan line being comprised of a plurality of successively disposed scanning positions,
- said array of beams being such that at any one time each beam lies on a different scan line and having a geometric shape such that a first line connecting the two points on the outline of said shape which are spaced furthest from each other and a second line perpendicular to and bisecting said first line and connecting two other points on said outline, are of comparable length, and
- means for selectively controlling each of said beams (80-120) at each of said scanning positions to effect said pattern.
A method of forming a scanned electron beam pattern which substantially avoids or reduces mutual beam repulsion, beam intermodulation, and grid mounting problems, comprising the steps of,
- emitting a plurality of electron beams which are disposed in relation to each other so as to form an array of beams,
- deflecting each of said beams through a plurality of spaced apart, parallel scan lines, each said scan line being comprised of a plurality of successively disposed scanning positions,
- said array of beams being such that at any one time each beam lies on a different scan line and having a geometric shape such that a first line connecting the two points on the outline of said shape which are spaced furthest from each other and a second line perpendicular to and bisecting said first line and connecting two other points on said outline, are of comparable length, and
- selectively controlling each of said beams at each of said scanning positions to effect said pattern.
Dependencies are inferred from the claim text.