Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Patent
1995-07-07
1998-03-24
Ramsey, Kenneth J.
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
451 29, H01J 900, H01J 190
Patent
active
057306354
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a method of providing a plurality of cavities and/or apertures arranged in a pattern in a plate or layer of non-metallic material.
Plates or layers of this patterned type of non-metallic, particularly hard, brittle materials such as glass, oxidic or ceramic material, are particularly used in microelectronic devices such as electro-luminescent gas discharge displays (for example, plasma displays), in field emission displays, cathode ray displays and in displays in which electrons are propagated in ducts having walls of electrically insulating material (referred to as insulating electron duct displays) in which the apertures or cavities are used for manipulating electron currents. They may be formed as (multi-apertured) control plates and provided with (addressable) electrodes cooperating with the apertures, as transport plates having a plurality of parallel cavities (transport ducts), or as apertured spacers (for example, between a control plate and the luminescent screen of a luminescent display).
U.S. Pat. No. 4,388,550 describes a luminescent gas discharge display. This display requires a control plate controlling the individual pixels. This control plate divides the inner space of such displays into two areas, a plasma area and a post-acceleration area. It comprises a "perforated" plate having an array of lines at one side and at the other side an array of columns of metal conductors or electrodes surrounding or extending along the perforations. These enable electrons to be selectively extracted from the plasma area through the apertures to the post-acceleration area and to be incident on the luminescent screen. Other gas discharge displays comprise, for example plates having (facing) cavities.
In a control plate, the number of perforations or apertures in a plate of the type described above is defined by the number of desired pixels.
Present-day television line scan patterns use, for example approximately 500.times.700 pixels having a horizontal pitch of 0.5 mm and a vertical pitch of 0.7 mm. These pixels define the pattern of apertures to be provided in the control plate of electrically insulating material.
It is known from EP 0 562 670 that these patterns can be manufactured by means of an apertured mask and a powder spray process. This process is possible by virtue of the large difference in production rate between the mask material and the material of the object which is to be provided with a pattern of apertures (particularly glass). A problem which appears to occur when a separate (metal) mask is used is, however, that the desired accuracies are not always achieved. The invention is based, inter alia, on the recognition that the mask may assume a convex shape during spraying, inter alia, with the result that it is no longer seated correctly on the product to be provided with a pattern, which is at the expense of the accuracy of this pattern. And that deformation may occur, even when a convex shape does not occur, or will occur to a minor extent, if a very good adhesion is ensured. A change of the absolute dimensions of the mask due to deformation does not only lead to inaccuracies in the pattern but also renders it unsuitable for repeated use.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a (preferably simple) method which mitigates the above-mentioned problems.
The method according to the invention is therefore characterized in that the pattern is made by means of the following steps: using a mask for limiting the areas where the jet impinges upon the surface, which mask has its surface on which the jet impinges coated with a layer preventing substantial mechanical (pressure) stresses from being generated in the mask during the process by the jet of powder particles.
The invention is based on the recognition that the deformation, or warping, is due to the fact that spraying the mask with the powder particles leads to a build-up of stresses, and that this problem can be reduced to a considerable extent if a layer is p
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patent: 5197234 (1993-03-01), Gillenwater
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de Haas Franciscus C. M.
Ligthart Henricus J.
Swinkels Petrus H. W.
Van Beek Johannes G.
Van Laarhoven Franciscus M. H.
Kraus Robert J.
Ramsey Kenneth J.
U.S. Philips Corporation
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