Abstract: A display arrangement includes a cathode ray tube, inside which tube a mask with at least one curved outer edge is located. The mask is at least partly attached by at least part of the curved edge to the tube by means of at least a diaphragm arrangement. The diaphragm arrangement includes at least one diaphragm part in the form of an elongated folded sheet including a straight fold, said sheet extending from the straight fold to a curved fold and from the curved fold to a curved part of the sheet for attaching to the curved mask edge. Preferably, the straight fold has a varying folding angle and the curved fold follows a curve which enables the transition from the straight fold to the curved fold to provide a folded sheet which is free from inherent mechanical stress.

Abstract: In present day color display tubes (1) the microphony performance of the shadow mask (13) is becoming increasingly important, especially in color display tubes (1) with a flat or nearly flat outer side of the display window (3). This invention discloses a mask frame (14) which by means of the transfer of vibrations from the outside of the color display tube (1) to the shadow mask (13) is hampered. This makes the shadow mask (13) less sensitive to vibrations, leading to an improved performance with respect to color purity. This object is achieved by providing the diaphragm parts (15), which form a part of the mask frame (14), with indents (27). Preferably, the skirt (19) of the shadow mask (13) is connected to the diaphragm part 15 by providing one spot weld (28) in between each pair of adjacent indents (27).

Abstract: In the manufacturing process of a color display tube (1), the display window (3) is assembled with the funnel shaped part (4) in a furnace by subjecting them to a heat treatment. This heat treatment can lead to deformation of the color selection electrode (12), because in color display tubes (1) with an invar shadow mask (13), the diaphragm parts (15) are made from invar as well, while the corner sections (16) are made from iron in order to obtain enough stiffness. The difference in expansion coefficient between invar and iron leads to shearing of the welds (22) that connect the diaphragm parts (15) to the corner section (16). To overcome this problem the invention proposes to provide the diaphragm parts (15) with slits (23) or impressions (24), which are arranged so that no stress occurs between the spot welds (22) when the color selection electrode (12) is heated.

Abstract: A display arrangement comprises a cathode ray tube, inside which tube a mask with at least one curved outer edge is located. The mask is at least partly attached by at least part of the curved edge to the tube by means of at least a diaphragm arrangement. The diaphragm arrangement comprises at least one diaphragm part (300) in the form of an elongated folded sheet comprising a straight fold (302), said sheet extending from the straight fold to a curved fold (304) and from the curved fold to a curved part (305) of the sheet for attaching to the curved mask edge. Preferably, the straight fold has a varying folding angle and the curved fold follows a curve which enables the transition from the straight fold to the curved fold to provide a folded sheet which is free from inherent mechanical stress.

Abstract: In the manufacturing process of a color display tube (1), the display window (3) is assembled with the funnel shaped part (4) in a furnace by subjecting them to a heat treatment. This heat treatment can lead to deformation of the color selection electrode (12), because in color display tubes (1) with an invar shadow mask (13), the diaphragm parts (15) are made from invar as well, while the corner sections (16) are made from iron in order to obtain enough stiffness. The difference in expansion coefficient between invar and iron leads to shearing of the welds (22) that connect the diaphragm parts (15) to the corner section (16). To overcome this problem the invention proposes to provide the diaphragm parts (15) with slits (23) or impressions (24), which are arranged so that no stress occurs between the spot welds (22) when the color selection electrode (12) is heated.