Videocolor

Carlo L Fonda

Paolo Spina

Nicola D Cagna

Eric M Jego

Marco Visconti

A process for forming a color selection mask for a CRT, in a press containing a punch and a counter-punch, after a temperature build-up stage in a shaping chamber, through the circulation of pressurized hot gas injected by inlets placed on the walls of the counter-punch, includes the step of distributing the hot gas through a distribution device to uniformly heat the mask's surface.

Forming process for a sheet of perforated metal and process

The present invention provides an improved method of forming a shadow mask for a color picture tube from a flat apertured mask. The mask has an central apertured portion, a solid border portion and a skirt portion. The improved method comprises several steps. First, a flat apertured mask is placed beneath an upper punch. Next, the periphery of the mask at the skirt portion is clamped. The punch then is pressed against the mask to contour the mask in its central apertured and solid border portions. Thereafter, the periphery of the mask at the skirt portion is unclamped, and the solid border portion of the mask is pressed between a bead die and the punch to form a peripheral bead in the solid border portion of the mask. Finally, the skirt portion is swept back to substantially parallel a central longitudinal axis of the formed mask, while the border portion is held between the bead die and the punch.

Method of forming a color picture tube shadow mask

In colored image tube having a perforated mask for the selection of colors in order that an electron beam intended for one color only reaches on the screen the luminescent material of that color. This mask presents an edge fixed to a frame through the intermediary of bimetallic strips. This frame is integral with the internal face of the glass wall of the tube adjacent to the screen. The bimetallic strips between the edge of the mask and the frame are flat. When the edge of the mask is inside the frame, one of the ends of each strip is welded to an internal projection of the frame and the other end to the edge of the mask in order to provide a space between the corresponding arm of the frame and the edge.

Shadow mask for a colored image tube and image tube comprising the same

In a color cathode-ray tube having a perforated mask for the selection of colors, one edge of the mask is fixed to the frame through intermediary of bimetallic strips. The frame is integral with the internal face of the glass wall of the tube adjacent to the screen. The bimetallic strips between the edge of the mask and the frame are disposed along the length of the vertical sides with first bimetallic strips at the center of each of the vertical sides and second bimetallic strips adjacent to the corners. The bending of the bimetallic strips adjacent to the corners is greater than the bending of the bimetallic strip in central position.

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Anagni, Italy

Carlo L Fonda