Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Wilhelmus Marinus Maria Van De Steen

Jean Winters

Arnoldus Antonius Maria Hendriks

Piet Christiaan Jozef Van Rens

Theodoor Christiaan Anna Hens

Rudolf Maria Jozef Voncken

Hernes Jacobs

J&ouml;rg Meissner

Jan Harmannus Post

Hendrik Pancratius Maria Bergmans

Maurice Andreas Wilhelmina Deuss

Ludovic Peter Willem Huysmans

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 color display tubes ( ) the color purity performance is of the utmost importance. One of the factors adversely affecting this color purity performance is the microphony behavior of the shadow mask ( ). Vibrations or shocks coming from outside the color display tube ( ) can be transferred to the shadow mask ( ) via the suspension means ( ) of the color selection electrode ( ). By introducing a vibration damping element ( ) coupled to the resilient element ( ) of the suspension means ( ), the amount of spot shift on the screen ( ) due to these vibrations is reduced by at least 50%. The vibration damping element ( ) is preferably a flat plate which is rigidly coupled with one side to the suspension means ( ), while the other side is in close contact with the resilient element ( ), as a result of which it is capable of absorbing said vibrations.

Color display tube with improved color selection electrode

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, which comprises an improved suspension system of the color selection electrode ( ). The color display tube has suspension means that are constructed so as to be self-locking. The suspension means ( ) are provided with an additional flat portion ( ). This plate has an aperture ( ) that is shaped such that it has at least three surfaces of engagement ( ) for the free end portion ( ) of the supporting elements ( ) connected to the inside of the upright edge ( ) of the display window ( ). When the color display tube is exposed to shock loading, the construction of the flat portion ( ) is capable of absorbing this shock without the color selection electrode ( ) becoming detached from the supporting elements ( ). The action is based on the friction between the surfaces of engagement ( ) and the free end portion ( ). When a force is applied in the plane ( ) of the resilient element ( ), the suspension means ( ) slip from their rest position and are locked by a surface of engagement ( ), whereby the preload caused by the resilient element ( ) and the spring ( ) will cause the suspension means ( ) to resume its original position. In this manner, a color display tube ( ) with a good positional stability of the color selection electrode ( ) is obtained. Furthermore, the color selection electrode ( ) can be reclaimed in case the color display tube ( ) is rejected because there is no need to weld the suspension means ( ) to the free end portions ( ) anymore.

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 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.

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.

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Eindhoven, Netherlands

Wilhelmus Marinus Maria Van De Steen