Electron gun with lens which changes beam into nonaxisymmetric shape
AssigneeHitachi, Ltd.
InventorsKazunari Noguchi, Syoji Shirai
Life of this patent
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Abstract
An electron gun has one first-type electron lens in the focusing electrode which changes the cross-sectional shape of the electron beam into a nonaxisymmetric shape with increase in the degree of the electron beam deflection by applying a first voltage varying in synchronism with deflection, and one second-type axisymmetric electron lens in the focusing electrode which weakens the lens power with increase in the degree of the electron beam deflection by applying a second voltage increasing with the degree of deflection.
Claims15
A cathode ray tube having an electron gun for producing electron beams which are to be scanned across a screen in response to deflection thereof, comprising:
- first electrode means for generating a plurality of electron beams and directing the electron beams along initial paths parallel to each other in a horizontal plane;
- and
- second electrode means disposed along said initial paths and including a focusing lens unit positioned adjacent to an accelerating electrode to which a highest voltage is applied for forming therebetween a main lens to focus said electron beams on the screen, said focusing lens unit having a plurality of electrode members forming at least one first-type electron lens which changes the cross-sectional shape of said electron beam into a nonaxisymmetric shape with increase in the degree of electron beam deflection in response to a first voltage varying in synchronism with said deflection and at least one second-type axisymmetric electron lens, separate from said main lens, whose lens power is weakened with increase in the degree of the electron beam deflection in response to a second voltage increasing with the degree of said electron beam deflection.
A cathode ray tube having an electron gun for producing electron beams which are to be scanned across a screen in response to deflection thereof, comprising:
- first electrode means for generating a plurality of electron beams and directing the electron beams along initial paths parallel to each other in a horizontal plane;
- and
- second electrode means disposed along said initial paths and including a focusing lens unit positioned adjacent to an accelerating electrode to which a highest voltage is applied for forming therebetween a main lens to focus said electron beams on the screen, said focusing lens unit having a plurality of electrode members forming at least one first-type electron lens which changes the cross-sectional shape of said electron beam into a nonaxisymmetric shape with increase in the degree of electron beam deflection in response to a first voltage varying in synchronism with said deflection and at least one second-type axisymmetric electron lens whose lens power is weakened with increase in the degree of the electron beam deflection in response to a second voltage increasing with the degree of said electron beam deflection;
- characterized in that said first voltage and the second voltage are equal;
- and characterized in that said main lens formed between the accelerating electrode and said focusing lens unit in said second electrode means has a stronger focusing function in the horizontal direction than in the vertical direction when the potentials of all electrode members of said focusing lens unit are equal.
Dependencies are inferred from the claim text.