DE2313197A1 - TARGET OR IMPACT ELECTRODE CONSTRUCTION AND METHOD OF MANUFACTURING THEREOF - Google Patents

Description

PATE NTAN WALTS 3Ü R O TlEDTKE - BüHLING - ΚϊΝΝΕ

TEL. (0811) 53 9β 53-56 TELEX: 524845 tipat CABLE ADDRESS: Germaniapatent Munich

8 0 0 0 M ü η chen 2 / Bavariaring4

P.O. Box 202403 _{l6> March}

Matsushita Electric Industrial Company, Limited

Osaka, Japan

Target or impingement electrode structure and method for its production

The invention relates generally to a target or Impact electrode assembly for use in charge storage tubes, specifically a method for Production of a target or target electrode structure, which has an organic compound film and this target or landing electrode structure.

The storage of image signals for a predetermined period of time is in many ways in the Telecommunications applications, including the display of a fixed image, for example of documents, in a video telephony system, the monitoring of images that are broadcast or on a Facsimile received and playback of

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Image signals that are interspersed with signals from conventional point television or from systems of civil aviation television or are connected. These needs are met by storage tubes of a number of different types are known. A known storage tube is provided with a target or landing electrode assembly, the one photoelectrically conductive layer or a photocathode, as it is commonly referred to, comprises which on one side of the target or impingement electrode structure is arranged and facing the scene to be imaged, and an insulating layer on the other hand for the purpose of storing charges that arise as a result of the incidence of light on the photocathode, the charge information being read out by the impact of an electron beam. Another known storage tube is instead of a photocathode for applying electron charges to the target or the impingement electrode a write cannon and a read cannon for discharging the electron charges. After all, serve with another Type of storage tube a single electron gun the dual purpose of writing and reading binary Information.

A target or impingement electrode structure used for such cases consists of a metal screen or grid or grid or the like, on which an inorganic compound such as Calcinmfluorid (CaPp) * silicon dioxide (SiOp) or such a porous inorganic compound as potassium

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chloride (KCl) is deposited or precipitated. A Another target or landing electrode structure of known type comprises a silicon substrate or a silicon pad and a layer of deposited thereon in the form of a screen or dots Silicon dioxide.

The important requirements for a charge storage target or a charge storage impingement electrode are the uniformity of the charge contrast, the resolution, the image gradation and the writing and reading speeds over the entire surface of the target or the impingement electrode. To meet these requirements, it is necessary to check the uniformity of the secondary emission properties, the film thickness of the insulator connection and the electrical resistance as well as the capacitance of the Ensure isolator connection.

In the known methods for producing a target or impingement electrode structure, it is necessary perform a number of complicated process steps which include vacuum evaporation, oxidation and photoetching. The products often have to be transported from one place to another during these process steps, and it it often happens that the products are exposed to the external environment, so that in this way the probability the introduction of undesirable or harmful foreign particles into the products and the contamination of the surface of the

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Products with dust, abrasion or the like. increases. The introduction .of foreign particles often has a non-uniformity of the Secondary emission characteristics result. In addition, Mnaus requires a long production time, which in turn leads to high production costs.

With the present invention, a target or. Creation of an impingement electrode structure in which one organic compound is used as a storage element.

Furthermore, the invention proposes a simplified method for producing a target or impingement electrode structure at low cost, which has a uniform storage time from one _{sample to} the other.

Finally, the invention provides an improved target or impingement electrode structure, which has a long service life.

The invention is explained in more detail below with reference to schematic drawings of exemplary embodiments.

1 shows an enlarged side view of a target or landing electrode assembly according to the invention, wherein one sees drops of an organic compound, which on a

Metal screen or grids are deposited; 309840/0862

Fig. 2 shows an enlarged side view of the

Target or impingement electrode structure of FIG. 1, in which the organic compound Spread over the surface of the screen or grid;

Fig. 3 shows an enlarged side view of the

Target or impingement electrode structure B of Fig. 2 in the solid state after a heating or burning process; and

4 shows an enlarged side view of two target or impingement electrode structures 3, which are connected to one another, the rear sides being adjacent to one another.

A first embodiment of the invention is shown in FIG. 1 and includes a target assembly, generally designated by the reference numeral 10. The target or impingement electrode structure 10 comprises a meshed or net-like metal screen or a corresponding grid pattern or the like, which is made, for example, of copper and has a thickness of approximately 3 microns. On the screen or the like. 11 drops 12 of an organic compound such as polyimide enamel, glaze, varnish, coating, known under the trade name of Dupont as "Polyimide Wire Enamel", or of polyamide imide enamel, glaze, varnish, coating are deposited or low

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was beaten by spraying or brushing, brushing or other known methods. The screen or the like. H ₀ is then placed in a gyroscopic device or a centrifugal device or a rapidly rotating device (not shown) and then rotated at high speed so that the drops 12 of the organic compound are driven sideways by centrifugal force and so that they continue to be driven by gravity downwards into the gaps, meshes, spaces or the like. 13 are driven. Because of the viscosity of the bonding material, the drops are spread over the entire surface of the screen, as shown in FIG. Under this condition, irregularities can possibly form over the target or impingement electrode surface. Next, the screen 11 is heated in air to a temperature in the range of 100 ° C to 200 ⁰ C and maintained at this temperature for about three hours. During the heating or heating process, the solvent of the organic compound is evaporated, with the result that a mechanical tension develops within the connection. This voltage acts in such a way that the surface irregularities are made to disappear, so that in this way a film 14 of an organic compound is obtained which has a uniform thickness over the entire surface of the target or the impingement electrode,

In Fig. 4 is a second preferred embodiment

■ - 7 -

illustrated form of the invention. The target or impingement electrode structure 15 comprises a pair of targets or impingement electrodes 10, which by means of the above-described Process have been established. The targets or impingement electrodes 10 are connected to one another so that the The backs face each other or lie on top of each other, with the screen sides facing outwards. The target or impingement electrode assembly 15 can, for example for two cannon storage tubes are used in which one side of the structure 15 as a target or impingement electrode for the write cannon and the other side as a target or impact electrode 'is used for the reading cannon.

In the arrangements described above, the storage time is determined by the resistance, the transverse about the spaces, gaps or the like. 13 is measured. Of the Resistance in turn is determined by the dimension of the space, the gap or the like. »And the thickness of the organic Connection resulting film 14 is determined. For example results in a screen, grid, grid or the like. from 500 to 1500 mesh and a film about 1 micron thick to 20 microns, a charge storage time in the range of 3 to 60 minutes.

The metal screen or the like. 11 can be formed from any metal * that is stable in vacuum, such as Copper, aluminum and silver, or it can be formed or mounted on a glass screen of such material.

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be built to prevent the deposition of metal or conductive Material on it enables and the manufacture of an optically flat or even surface permitted. In addition, the screen 11 may be of a type of grid, which comprises a plurality of parallel metal strips. If metal strips in the arrangement of the target or landing electrode assembly 15 are used, then the targets or impact electrodes 10 are connected to one another in such a way that the * Stripes on one side of the target run perpendicular to the direction of the stripes on the other side of the target.

A test has shown that the inventive

Target or impingement electrode structure no deterioration in performance . exhibited after having been for a period of 6 months was exposed to an impacting electron beam, which by means of a potential of 100 eV onto the surface of the Construction was accelerated.

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Claims (1)

Claims 1. Process for the production of a target or impingement electrode structure for use in charge storage tubes, characterized by the following process steps: Deposition or precipitation of drops of a organic compound of a resistance of at least 15th
10 ohm-cm on a metal screen in which there are gaps, gaps or the like. are located; Rotating the screen at a speed sufficient to drive the drops sideways so that these the spaces, gaps or the like. to complete; and Heating the organic compound to achieve a uniform thickness of the structure. 2. The method according to claim 1, characterized in that the organic compound is ^{heated to a temperature of about 100 0} C to about 20O ⁰ C and held at this temperature for about three hours. 3. The method according to claim 1 or 2, characterized characterized in that the organic compound is selected from the group consisting of polyimide and polyamide-imide is selected. A.! Target or impact electrode assembly for the ^ 309 84 0/0 862 23131S7 . - 10 - Use in charge storage tubes, in particular produced by the method according to one of claims 1 to 3, geke η η ζ eich η et by a screen (11) in which there are gaps, gaps or the like. (13) and a film (14) of an organic compound having a resistance of at least 10 ^ ohm-cm deposited on the screen . . ■ 5. target or impingement electrode structure according to claim 4, characterized in that the organic Compound of that consisting of polyimide and polyamide-imide Group is selected. 6. target or impingement electrode structure according to claim 4 or 5, characterized in that the organic Film (14) has a thickness of 20 microns or less. 7 · Target or impingement electrode structure according to claim 4, 5 or 6, thereby g e k e η η ze i c h η e t that the Screen, the grid, the grid or the like. (11) such or is from 500 to 1500 mesh. 309840/0362