Abstract: The present invention relates to a colour picture tube and to a manufacturing method for a colour picture tube. The colour picture tube includes a shadow mask which is secured to a mask frame. In order to improve the shielding effect, a shielding plate, which shields external magnetic fields, is secured to at least one longitudinal bar of the mask frame. By means of such a shielding plate, the picture quality of a colour picture tube can be improved and the manufacturing efforts can be simplified in comparison with conventional colour picture tubes.

Abstract: The invention refers to a method of manufacturing color CRTs, in which the reject rate is reduced in by increasing the viscosity of the cleaning bath.

Abstract: A color picture tube having a mask-frame combination which consists of a rectangular frame of a first material and of a mask of a second material, wherein the mask is connected to the frame by a plurality of welding spots, and notches and decoupling slots whose dimensions have a specific ratio with one another are provided at both sides of welding spots at the shorter sides.

Abstract: According to the prior art, springs (11/18) of a combination mask/frame (10) of picture tubes are joined to the frame by resistance welding. This welding technique is also customary when one of the springs (18) has a centering washer (20) at its free end. When combination mask/frames (10) designed in this manner are snapped repeatedly into and out of the shielding case (15), and when the shielding case (15) is stabilized or fritted to the neck of the picture tube, it can happen that the expansion characteristics of the combination mask/frame (10) are not homogeneous at the fourth spring (18) as compared to the other springs (11) under the picture tube's operating conditions.

Abstract: The following steps are performed in a method of lacquering the luminophore layer of a color picture tube:the luminophore layer is first prewetted,a first aqueous dispersion of a lacquer is applied to the prewetted luminophore layer,this first dispersion is fully dried and heated to above the film formation temperature of the lacquer, thereby producing a first lacquer film,a second aqueous dispersion is applied directly to the first lacquer film, where the said second aqueous dispersion has exactly the same components as the first dispersion and the concentration of the components in the second dispersion corresponds at least to a large extent to the concentration of these components in the first dispersion, andthis second dispersion is fully dried and heated to above the film formation temperature of the lacquer, thereby producing a second lacquer film.

Abstract: A mask-frame combination for a color picture tube includes a metal mask (12) placed over the frame with a skirting that overhangs the frame with an overhang height (H) and that is bent back toward the frame, and includes spot welds (15.1-15.12) located around the mask skirting for attaching the mask to the frame, wherein the mask skirting (13) bears against the outside of the frame (11) for attaching the mask where it is bent back, wherein the spot welds are arranged on each side of the long sides in such a manner that in each long side there is a central spot weld situated close to the mid-point of the long side and an outer spot weld on each side of the central spot weld and separated from the central spot weld by a distance of between D/14 and D/9, where D equals the length of the diagonal of the frame, and wherein the mask skirting is provided on each long side with openings (17) on two sides of each outer spot weld and adjacent thereto.

Abstract: The following steps are performed in a method of lacquering the luminophore layer of a colour picture tube:the luminophore layer is first prewetted,a first aqueous dispersion of a lacquer is applied to the prewetted luminophore layer,this first dispersion is fully dried and heated to above the film formation temperature of the lacquer, thereby producing a first lacquer film,a second aqueous dispersion is applied directly to the first lacquer film, where the said second aqueous dispersion has exactly the same components as the first dispersion and the concentration of the components in the second dispersion corresponds at least to a large extent to the concentration of these components in the first dispersion, andthis second dispersion is fully dried and heated to above the film formation temperature of the lacquer, thereby producing a second lacquer film.

Abstract: In a combined mask/frame for a colour picture tube, a mask is attached to a frame by means of spot welds which are positioned at the corners and adjacent to the long center axis and the short center axis. Of central importance is the fact that all spot welds are arranged as double spot welds instead of single spot welds which were usual until now. The single spot welds of each double spot weld are located basically at the same height of the mask skirt but are slightly separated from each other.

Abstract: The invention relates to a mask-frame assembly for use as a color-selecting-electrode system in a color-television tube. The structure features of the mask allow for a simplified method of manufacturing such an assembly. The mask and frame are subjected to a common surface treatment in accordance with a particular temperature program after joining them together at given points by spot welding.