Color cathode ray tube
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsKoji Shimada, Hiromi Wakasono
Life of this patent
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Abstract
In a color cathode ray tube in which a shadow mask and an inner magnetic shield are supported by a mask frame and an electron shield is provided in the mask frame, at least a part of the electron shield is made to have a smaller anhysteretic magnetic permeability than the shadow mask, the mask frame and the inner magnetic shield when an applied magnetic field is 800 A/m (10 Oe). Since the magnetic resistance of the electron shield increases, it is possible to reduce a leakage magnetic field from a tube-axis-side edge of the electron shield. Thus, a color cathode ray tube that reduces mis-landing due to a terrestrial magnetism and has no color displacement can be provided.
Claims3
A color cathode ray tube comprising:
- a mask frame;
- a shadow mask fixed to the mask frame;
- an inner magnetic shield supported by the mask frame;
- and
- an electron shield extending inwardly of the mask frame;
- wherein at least a part of the electron shield is formed of a material having a smaller anhysteretic magnetic permeability than another part of the electron shield, the shadow mask, the mask frame and the inner magnetic shield when an applied magnetic field is 800 A/m (10 Oe), and
- the part of the electron shield having the smaller anhysteretic magnetic permeability extends to a point inward of a tube axis side edge of the mask frame.
Dependencies are inferred from the claim text.