Corrector for bundle deflection distortion in multibeam cathode ray tubes

Claim 1

A display system including a multiple beam cathode ray display tube comprising an array of cathodes and beam forming means, for projecting a matrix array of electron beams onto the screen of said display tube, deflection means for simultaneously deflecting said bundle of electron beams to form a scanning pattern, means external to said tube disposed in electromagnetically interactive relationship with said bundle of electron beams for simultaneously focusing each of said electron beams of said bundle of electron beams and for rotating said bundle of electron beams by an amount sufficient to counter undesired rotational distortion of said bundle, said means including a pair of coils, each coil comprising a single winding, wound to selectively provide opposing axial magnetic fields, and means connected to said coils for supplying corrective signals thereto comprising means for dynamically energizing said coils as a function of the instantaneous location of said projected matrix array on the screen of said display tube.

Claim 6

An apparatus for forming a multiple scan line electron beam pattern on the screen of a cathode ray display tube which substantially avoids or reduces mutual beam repulsion and beam intermodulation problems comprising, electron beam emitter means (14) for emitting a plurality of electron beams which are disposed in relation to each other so as to form a matrix array of beams, means (18) for deflecting each of said beams along a plurality of spaced apart, parallel scan lines, each said scan line being comprised of a plurality of successively disposed scanning positions of a particular beam, said array of beams being such that at any one time each beam lies on a different scan line, split contiguous focus coil means each having at least one winding for selectively producing opposed axial magnetic fields within said tube and, means comprising memory means addressable as a function of the instantaneous beam deflection signals for dynamically supplying corrective signals to said two split focus coil windings which are a function of the beam displacement to simultaneously correct for rotational distortions of said matrix array of beams and maintain optimal focus of said beams.

Claim 7

An apparatus for forming a multiple scan line electron beam pattern on the screen of a cathode ray display tube which substantially avoids or reduces mutual beam repulsion and beam intermodulation problems comprising, electron beam emitter means (14) for emitting a plurality of electron beams which are disposed in relation to each other so as to form a matrix array of beams, means (18) for deflecting each of said beams along a plurality of spaced apart, parallel scan lines, each said scan line being comprised of a plurality of successively disposed scanning positions of a particular beam, said array of beams being such that at any one time each beam lies on a different scan line, split contiguous focus coil means each having at least one winding for selectively producing opposed axial magnetic fields within said tube and, means comprising memory means addressable as a function of the instantaneous beam deflection signals for dynamically supplying corrective signals to said two split focus coil windings which are a function of the beam displacement to simultaneously correct for rotational distortions of said matrix array of beams and maintain optimal focus of said beams.

Claim 9

A method for forming a multiple scan line electron beam pattern which substantially avoids or reduces mutual beam repulsion and beam intermodulation problems, comprising the steps of, forming a plurality of electron beams which are disposed in relation to each other so as to form an M by N matrix array of beams, wherein both M and N are greater than 1 unit and wherein a unit is equal to the minimal spacing between two adjacent beams, deflecting each of said beams along a plurality of spaced apart, parallel scan lines, each said scan line being comprised of a plurality of successively disposed scanning positions of a particular beam, said array of beams bieng such that at any one time each beam lies on a different scan line and dynamically correcting for rotational distortion of said array of beams by providing two selectively opposing axial magnetic fields within the neck of said tube between the cathode structure and the deflecting means therefor wherein said step of dynamically correcting comprises supplying predetermined corrective signals from a previously loaded memory means.

Claim 10

A method for forming a multiple scan line electron beam pattern which substantially avoids or reduces mutual beam repulsion and beam intermodulation problems, comprising the steps of, forming a plurality of electron beams which are disposed in relation to each other so as to form an M by N matrix array of beams, wherein both M and N are greater than 1 unit and wherein a unit is equal to the minimal spacing between two adjacent beams, deflecting each of said beams along a plurality of spaced apart, parallel scan lines, each said scan line being comprised of a plurality of successively disposed scanning positions of a particular beam, said array of beams bieng such that at any one time each beam lies on a different scan line and dynamically correcting for rotational distortion of said array of beams by providing two selectively opposing axial magnetic fields within the neck of said tube between the cathode structure and the deflecting means therefor wherein said step of dynamically correcting comprises supplying predetermined corrective signals from a previously loaded memory means.