Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Jean Winters

Wilhelmus Marinus Maria Van De Steen

Arnoldus Antonius Maria Hendriks

Piet Christiaan Jozef Van Rens

Theodoor Christiaan Anna Hens

Rudolf Maria Jozef Voncken

Adrianus J Van Mensvoort

Johannes H Gijrath

Theodoor C Hens

Maurice Andreas Wilhelmina Deuss

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.

Display arrangement with reduced mechanical stress

In the manufacturing process of a color display tube ( ), the display window ( ) is assembled with the funnel shaped part ( ) in a furnace by subjecting them to a heat treatment. This heat treatment can lead to deformation of the color selection electrode ( ), because in color display tubes ( ) with an invar shadow mask ( ), the diaphragm parts ( ) are made from invar as well, while the corner sections ( ) 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 ( ) that connect the diaphragm parts ( ) to the corner section ( ). To overcome this problem the invention proposes to provide the diaphragm parts ( ) with slits ( ) or impressions ( ), which are arranged so that no stress occurs between the spot welds ( ) when the color selection electrode ( ) is heated.

Color display tube provided with a color selection electrode

A color display tube ( ) is disclosed with an improved suspension of the color selection electrode ( ). In order to have a color display tube with good properties of, for instance, color purity, it is of eminent importance that the color selection electrode ( ) has and excellent positional stability. Especially wide screen tubes seem to be more sensitive to external shocks by which the color selection electrode ( ) may shift and cause discolorations. The positional stability of the color selection electrode ( ) can be improved by decreasing the friction between the color selection electrode ( ) and the supporting elements ( ) in the display window ( ) of the color display tube ( ). This is achieved by applying a supporting element ( ) with a free end portion ( ) having a small diameter and by applying a low force between the suspension means ( ) and the supporting elements ( ). As a consequence of the lightweight construction of the color selection electrode ( ), this force can be lowered to about 4 newtons.

Color display tube with improved suspension of the color selection electrode

A color display tube (,) is disclosed with an improved suspension of the color selection electrode (,). In order to have a color display tube (,) with good properties of, for instance, color purity, it is of eminent importance that the positional stability of the color selection electrode (,) is excellent. Especially wide-screen tubes seem to be more sensitive to shocks by which the color selection electrode (,) may shift and cause discolorations. The positional stability of the color selection electrode (,) can be improved by increasing the stiffness of the corner sections (,) of the color selection electrode (,). This can be realized by introducing an additional support plate (,) in the corner section (,). Also the optimization of the position of the supporting element (,) with respect to this corner section (,) yields an improvement.

A color cathode ray tube comprises a color selection electrode which is secured to a frame and a magnetic screening cap. The frame has two diaphragm portions one of which is located near the color selection electrode and the other is further removed from the color selection electrode. The distance between the electron beams deflected towards the outermost apertures of the color selection electrode and the further removed diaphragm is at least 1 cm. By virtue thereof, the negative influence of the frame on the screening effect of the magnetic screening cap is substantially reduced.

Colour cathode ray tube having a screening cap

A color selection electrode is suspended in a color display tube from pins which are provided in the corners of the display window. The suspension means comprise a resilient element which is secured to the color selection electrode, and a slide plate slidably secured relative to the flat resilient element rigidly secured to the pin. During the suspension the position of the color selection electrode is adjusted, and the slide plate is rigidly secured to the resilient element.

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Eindhoven, Netherlands

Jean Winters