U.S. Philips Corporation

Leopold C M Beirens

Nicolaas G Vink

Tjerk G Spanjer

Albertus A S Sluyterman

Martinus H E Jansen

Lucius T Vinkenvleugel

A deflection unit of a cathode ray tube is provided with a cooling fan. The fan includes means for reducing the disturbing effect of the electric field generated by the fan on the deflection of the electrons, or the fan is arranged in such a manner that the disturbing effect is small.

Cathode ray tube having a deflection unit

The invention relates to a color display device comprising an in-line electron gun ( ) for generating three electron beams ( ), and a convergence unit ( &prime;) to dynamically influence the convergence of the electron beams, preferably to decrease a distance (p) between the electron beams. The convergence unit ( &prime;) comprises a ring-shaped element ( &prime;) having four coils ( &prime;). The coils ( &prime;) comprise electrically conductive wires, which have been toroidally wound in a winding direction and according to a winding density distribution N (&phgr;) given by N (&phgr;)&equals;N cos (2&phgr;). Here &phgr; is an angle enclosed by the X-direction and a line between an element of the coil and the center, which ranges between 0&deg; and 360&deg;, N is the winding density at &phgr; equal to 0&deg;, and the sign of N &phgr; denotes the winding direction.

Color display device having quadrupole convergence coils

The invention relates to a color display device comprising an in-line electron gun ( ) for generating three electron beams ( ), and a convergence unit ( ) to dynamically influence the convergence of the electron beams, preferably to decrease a distance (p) between the electron beams. The convergence unit ( ) comprises a ring-shaped element ( ) having four coils ( ) and a longitudinal axis ( ). A cross-section of the ring-shaped element ( ) with a plane perpendicular to the longitudinal axis ( ) is a circle with the longitudinal axis as its center and the ring-shaped element ( ) forming the circumference. Each coil extends over the circumference over an angle &phgr; having a value between &deg; and

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Eindhoven, Netherlands

Leopold C M Beirens