U.S. Philips Corporation

Jan Verweel

Hinne Zijlstra

Willem M Van Alphen

In a first method, a meander-shaped coil (20,21) is provided on each side of the mask (7) having apertures (9). The coil (21) is oriented perpendicularly relative to the coil (21). If a current flows through the coils (20,21) in the correct direction, a magnetic quadrupole is formed along the circumference of each aperture (9). In a second method, a holder (30,31) with permanent magnetic strips (32) is provided on each side of the mask (7). The strips (32) in the one holder (30) are oriented perpendicularly relative to the strips in the other holder (31). A coil 40 is provided around the holders 30 and 31 with which a decaying magnetic alternating field, is generated which initially drives the material of the mask (7) on both sides of the hysteresis curve into saturation. After the decay of said alternating field a magnetic quadrupole is present along the circumference of each aperture (9).

Devices for manufacturing a magnetic quadrupole post-focusing mask

In a first method, a meander-shaped coil (20,21) is provided on each side of the mask (7) having apertures (9). The coil (21) is oriented perpendicularly relative to the coil (21). If a current flows through the coils (20,21) in the correct direction, a magnetic quadrupole is formed along circumference of each aperture (9). In a second method, a holder (30,31) with permanent magnetic strips (32) is provided on each side of the mask (7). The strips (32) in the one holder (30) are oriented perpendicularly relative to the strips in the other holder (31) A coil 40 is provided around the holders 30 and 31 with which a decaying magnetic alternating field is generated which initially drives the material of the mask (7) on both sides of the hysteresis curve into saturation. After the decay of said alternating field, a magnetic quadrupole is present along the circumference of each aperture (9).

Methods of manufacturing a color display tube having a magnetic

A cathode ray tube for displaying colored pictures of the post-focusing type. The color selection means are formed by a plate which is provided with a large number of apertures, which plate is provided on one side with a first plate of parallel strips of hard magnetic material provided between the rows of apertures. The color selection means are magnetized in a direction perpendicular to the plane of the plate so that a magnetic quadrupole is obtained in each aperture.

Cathode-ray tube having a magnetic quadrupole shadow mask

A cathode ray tube for displaying colored pictures of the post focusing type. A magnetic quadrupole lens is formed in each aperture of the color selection means. The defocusing direction of quadrupole lenses is parallel to the phosphor strips of the display screen.

Shadow mask having magnetic quadrupoles around each mask aperture

A post-focusing type color cathode ray tube comprising a quadrupole lens formed in each aperture of the color selection mask.

Growing community of inventors

Eindhoven, Netherlands

Jan Verweel