Arc suppression in a cathode ray tube
AssigneeOwens-Illinois, Inc.
InventorsJosef Francel, Galen D. Lemke
Life of this patent
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Abstract
Internal arcing in a cathode ray tube is substantially prevented by coating a portion of the interior of the funnel and neck of the tube with an electrically conductive composition, and coating a portion of the interior of the funnel and neck of the tube with an electrically resistive composition. The electrically conductive composition comprises about 10-30 weight percent iron and about 90-70 weight percent of a glass frit. The electrically resistive composition comprises about 8-24 weight percent iron, about 2-8 weight percent TiO.sub.2 and about 90-68 weight percent glass frit. The use of conventional "dag" coatings is eliminated. The cathode ray tube is especially useful as a picture tube in a color television receiver in which high operating voltages are employed.
Claims8
An electrically conductive composition for use on interior surfaces of a funnel portion and neck portion of a cathode ray tube in order to substantially suppress internal arcing during operation of said tube, said composition consisting essentially of a substantially homogeneous mixture of:
- a. about 10-30 percent by weight of iron having a particle size of about 0.1-20 microns;
- and
- b. about 90-70 percent by weight of a lead borate or lead zinc borate glass frit having a particle size such that about 100% of the glass frit particles pass a 100 mesh U.S. Sieve Series screen;
- said composition being capable of being fired on said funnel and neck portions at a temperature of about 400.degree.-450.degree. C. to form layers each layer having a thickness of about 18-70 microns and an electrical resistivity of about 1 ohm to about 2000 ohms;
- said composition being capable of substantially suppressing arcing within said tube during operation of said tube at a voltage up to about 40,000 volts.
An electrically resistive composition for use on interior surfaces of a funnel and neck portion of a cathode ray tube in order to substantially suppress internal arcing during operation of said tube, said composition consisting essentially of a substantailly homogeneous mixture of:
- a. about 8 - 24 percent by weight of iron having a particle size of about 0.1-20 microns;
- b. about 2 - 8 percent by weight of TiO.sub.2 having a particle size of about 0.1-45 microns;
- and
- c. about 90 - 68 percent by weight of a lead borate or lead zinc borate glass frit having a particle size such that about 100% of glass frit particles pass a 100 mesh U.S. Sieve Series screen;
- said composition being capable of being fired on said funnel and neck portions at a temperature of about 400.degree. - 450.degree. C to form a layer having a thickness of about 18 - 70 microns and an electrical resistivity of about 0.5 megohm to about 80 megohms;
- said composition being capable of substantially suppressing arcing within said tube during operation of said tube at a voltage up to about 40,000 volts.
Dependencies are inferred from the claim text.