DE2700616A1 - A METHOD OF MANUFACTURING A COLOR TUBE AND A COLOR TUBE MANUFACTURED BY THIS METHOD - Google Patents

Description

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A method of manufacturing a color picture tube and a color picture tube manufactured by this method

The invention relates to a method for producing a color picture tube contained in an evacuated envelope an electrode system for generating two electron beams, a screen with a plurality of in different colors of illuminated areas is covered, sovae arranged a short distance in front of the screen Color selection means, with the help of which each electron beam illuminates areas of a certain color is assigned, this color selection means a first

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ORIGINAL

and a second lens electrode system and wherein a lens electrode belonging to the first system
via an insulating body with one to the second system
associated lens electrode is connected.

The invention also relates to a color picture tube manufactured by this method.

In color picture tubes, color selection means are used in the form of a perforated plate arranged a short distance in front of the screen, which is usually referred to as a perforated mask.
Such a mask has the disadvantage that a large part, e.g. B. 80 to 85 %, of the electrons being intercepted,
whereby the highest achievable brightness of the reproduced image is limited. It is known to increase the brightness of the displayed image by enlarging the openings in the color selection means and by refocusing the
To enlarge electron beams.

A tube in which the electron beams are refocused is known from US Pat. No. 3,398,309. In this tube, a unipotential type lens is formed in each of the openings of the color selection means. For such a lens there is a relatively large voltage difference
between the electrodes that make up the lens.

The object of the invention was to provide a method for producing a color picture tube of the refocusing type in which the color selection means are of simple construction. Furthermore, the invention is to provide a color picture tube in which the color selection means contain only two lens electrode systems in such a way that when one is applied
Voltage difference between these two systems in each of the openings of the color selection means a quadrupole lens is formed.

To solve this problem, a method for producing a color picture tube of the type mentioned according to the invention is

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Finding characterized in that for the production of the Color selection means from an electrically insulating foil is assumed, on the one hand a first lens electrode system and on the other hand a second lens electrode system is formed, while the desired openings in the color selection means are obtained by the insulating Foil is etched through locally.

Preferably, for the production of the color selection means, one coated on both sides with a metal layer is used insulating film assumed from which the one metal layer locally to form the first lens electrode system and the other metal layer is locally etched to form a second lens electrode system. That Local etching of the metal layers can be carried out by means of photographic techniques known per se.

According to another embodiment of the erfindungsgomäße In the process, the two lens electrode systems are directly applied by depositing metal on the respective one Sides of the insulating film received. In order to obtain the desired pattern of the lens electrode systems, v / any photographic techniques can be used, while known techniques, such as vapor deposition or sputtering, can be used to deposit the metal.

A particularly favorable embodiment of the color selection means is obtained in that a lens electrode system is formed on one side of the insulating film, which consists of a provided with openings arranged in rows metal coating that on the other side of the insulating film a lens electrode system is formed, which consists of a metal grid interconnected between said Rows of openings of arranged strips consists, and daij the film is etched through at least at the locations of the openings mentioned. In those obtained according to this embodiment Color selection means v / ird when applying a voltage

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ORIGINAL INSPECTtb "*

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Difference between the first and the second lens electrode system a quadrupole lens is formed in each of the openings of the color selection means, the electric field of which perpendicular or nearly perpendicular to the electron beams passing through them. According to the invention built-up color selection means then have the advantage that they are compared to the color selection means according to the above US-PS can be operated with a lower difference in energy efficiency because a viorpole lens is relatively stronger than is a unipotential lens.

The fact that a quadrupole lens will focus in one direction and in a direction perpendicular to that direction defocused is basically not a cause for concern if the areas that light up on the screen almost match the shape have parallel strips, the longitudinal direction of which is parallel to the defocusing direction of the quadrupole lenses.

Another embodiment of the color selection means is obtained in that on one side of the insulating Foil a lens electrode system is formed, which consists of a first metal grid of interconnected strips consists that on the other side of the insulating film, a lens electrode system is formed that of one second metal grid consists of interconnected strips, this second grid crossing the first grid, and that the foil is then etched through between the strips belonging to the same grid. Even with those obtained in this way Color selection means is a quadrupole lens in each of the openings when applying a voltage difference between the first and second grids.

In the case of the color selection agents obtained by this last process the insulating film does not contribute or almost no longer contributes to the strength of the color selection means. In particular if only parts of the insulating film remain at the intersection points of the strips, the mechanical strength

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ORIGINAL INSPECTED

The speed of the color selection means is entirely due to the strength of the strips forming the grids. It is then preferable to stiffen at least one of the grids in that an additional metal layer is applied thereon. this can be obtained by galvanic or chemical means.

According to the invention, suitable insulating foils are foils of glass and in particular of plastic. Preference is given to using polyimide films, the polyimide in particular of 1,2,4,5-benzenetetracarboxylic acid dianhydride and 4,4'-diaminodiphenyl ether is suitable for the purpose sought according to the invention.

The invention is explained in more detail below, for example with reference to the drawing. Show it Fig. 1 is a horizontal section through a color picture tube according to the invention,

2 shows the principle of the refocusing effect of a quadrupole lens,

Figures 3a, b, c and d show an embodiment of the invention Procedure,

Fig. 4 shows a detail of the color selection means shown in Fig. 3d, and

Figure 5 shows a detail of another embodiment of the color selection means.

The tube shown in Fig. 1 contains a glass bulb 1, Means 2 for generating three electron beams 3, 4 and 5, a screen 6, color selection means 7 and deflection coils 8. The electron beams 3, 4 and 5 are generated in a plane, namely the plane of the drawing of FIG. 1, and by the Deflection coils 8 deflected over a plurality of red, green and blue flashing fluorescent strips, their longitudinal direction is perpendicular to the plane of the drawing of FIG. During normal operation of the tube, the fluorescent strips are vertical directed and Fig. 1 thus shows a horizontal

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Cut through the tube. The color selection means 7 contain a multiplicity of openings 9, which are only shown schematically in FIG. 1 are shown. The three electron beams 3, 4 and 5 pass through the openings 9 at a small angle each other and therefore only meet fluorescent strips of a certain color. The openings 9 in the color selection means 7 are therefore very precisely aligned with the fluorescent strips of the screen 6.

Fig. 2 illustrates the principle of refocusing Effect of a quadrupole lens. They are part of the color selection means 7 and one of the openings 9 is shown. The potential profile along the edge of the opening 9 is with + »-> +» - specified in such a way that a four-pole field is generated. The electron beam that passes through the opening 9 is focused in the plane drawn horizontally and in the vertical drawn plane defocused, which, if the screen exactly in the horizontal focus point is located, the electron spot 10 is formed. As will be explained in more detail, it is best not to look closely to focus the screen 6, whereby a somewhat wider electron spot is obtained. It affects the focus only to an insignificant extent when the electron beam passes the opening 9 at a small angle. The color choice of the three electron beams 3> 4 and 5 takes place in exactly the same way as in the known shadow mask tube. Due to the strong focusing, however, the opening 9 can be much larger than in the known shadow mask tube, as a result of which a much larger number of electrons will hit the screen 6 and a brighter picture will be obtained. The defocusing in the vertical direction is unobjectionable if fluorescent strips are used that face the longitudinal direction of the spot 10 are parallel.

A first embodiment of the color selection means 7 is explained with reference to FIGS. 3a to 3d. A polyimide film 20

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ORIGINAL · "INSPECTED

with a thickness of 125 μm is covered on both sides with a metal layer 21 or 22 coated. The film consists of the polyimide of 1,2,4,5-benzene tetracarboxylic acid dianhydride and 4,4'-diaminodiphenyl ether. Such a film is commercially available under the trade mark "Kapton". The metal layers v / earth attached to the film by vapor deposition or sputtering and can e.g. B. made of copper, nickel, cobalt, Aluminum, iron, gold or a double layer of two of these metals exist. Preferably there is at least one these layers made of a ferromagnetic !! Material to the electron beams generated in the tube against the earth's magnetic Shield field. A double layer is also possible, such as a first layer of copper on top of one second layer / j ^ lrifkel attached v / ird. The nickel layer can be done by galvanic means or by a process known as electroless nickel plating ("electroless nickel-plating ").

After the metal layers 21 and 22 to a thickness of about 30 / um are brought to the layered plate of Fig. 3a obtain. A layer of photoresist material is then applied to the two surfaces of this layered plate, These layers are each converted into a pattern of parallel bars by photographic exposure and development will. The exposed after development parts of the metal layers 21 and 22 are with the help of a suitable Etching liquid removed.

After removing the remaining photoresist material is then a film 20 covered on both sides with metal strips 23 and 24 is obtained, as shown in FIG. 3b. In this the strips 23 form a first lens electrode system and the strips 24 form a second lens electrode system. The connection between the conductors belonging to the same system is established in that at the ends of the conductors a connecting strip (not shown in the drawing) is retained.

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In the next stage of the process shown in FIG. 3c the parts of the film 20 lying between the conductors 23 are etched without the conductors being attacked. One for this purpose. a suitable etchant consists of hydrazine hydrate or a dilute lye, preferably KOH, and is sprayed onto the side of the film 20 covered with the strips 23. By removing said parts of the film, a matrix of rectangular openings 9 is obtained at the same time, after which basically the color selection is finished.

Although the side surfaces of the bars 27 remaining from the film 20 are shown straight in FIG. 3c, occurs in reality a certain undercut. This is un-

.dq through

questionable because the bars 27 are better shielded from the electron beams by the lens electrodes. The possibility of a possible charging of the insulating material

the

terials by / electron beams can thereby be further degraded v / ground that the part of the beams 27 lying between the conductors 24 is removed. As shown in Fig. 3d is, then only blocks 26 of the original film remain, which are located at the points where the ladder 23 cross the ladder 24.

Many variations on the method described above are possible. Instead of first the metal layers 21 and 22 on to attach the foil and to etch the ladder from it, it is also possible to use the ladder directly according to the desired To apply pattern to the foil. For this purpose, the film is coated on both sides with a layer of photoresist material, in a bar pattern is attached by photographic means. Then a metal layer is applied over this pattern, which adheres to the parts of the film that are not coated with photoresist material. Eventually the remaining will Pbotoresistoiaterial removed from the foil and only the metal directly adhering to the foil according to the desired one Pattern remains on the film.

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ORlGlNAL INSPECTED

It is also possible, first of all, from the onto the film vapor-deposited Motallschichten to etch the conductor and then z. B. to bring the conductor to the desired thickness by electrolytic means.

Instead of vapor deposition or sputtering, it is still possible to obtain the layered plate according to FIG. 3a by that the film 20 is coated on both sides with a metal foil. The metal phones are grounded on one side with a Wets adhesive that is made from the polyamide of 1,2,4,5-benzene tetracarboxylic acid dianhydride and 4,4'-diaminodiphenyl ether. The two metal foils are then against the polyimide foil 20 is printed and the structure thus obtained is placed in an oven under a non-corrosive atmosphere for about Heated to a temperature of 350 ° C. for 30 minutes. The polyamide v.'ird is converted into the polyimide with expulsion of water and the metal foils adhere firmly to the foil 20. Incidentally, the method can be continued in the manner described with reference to FIGS. 3b, 3c and 3d.

Although the invention has been explained on the basis of an insulating film made of polyimide, it is also possible to make films another insulating material, such as. B. glass to use. The advantage of a plastic film, however, is that it is not fragile and easy to handle.

In FIG. 4, a part of the color selection means according to FIG. 3d, lying around an opening 9, is shown on an enlarged scale. The strips 23 and 24 now have a width of 0.24 and each of the openings 9 forms a square of 0.56 0.56 mm, so that the permeability of the color selection means is about 50 % . For refocusing the electron beams, of which only the beam directed onto the fluorescent path G is shown in FIG. 4, the color selection means can be operated at the following voltages.

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- 10 -ORIGINAL · INSPECTED '"

At a potential of the screen 6 of 25 kV and one Potential of the horizontal conductors 23 of 25 »45 IcV and the vertical conductor 24 of 24.55 kV, the focal length of the four-pole lens is 18.0 mm in the center of the screen normal incidence and 12.7 mm at the edge of the curved screen, where the electron beams are at an angle from about 37 ° to the normal on the screen. The distance between the color selection means 7 and the screen 6 is 15 mm in the middle and 10 mm on the edge, which means that the focus point of the four-pole lens is just a little bit beyond of the screen. This prevents a so-called focus ring from being visible on the screen is. The electron impact spots are then in the middle of the screen 0.10 mm wide and 0.09 mm wide at the corners. A suitable width of the fluorescent strips R, G and B is then 0.13 mm. The remaining part of the surface of the screen can optionally be covered with a light-absorbing Material to be coated.

In the illustrated in Fig. 5 the color selection means 7, the EIRC ^{Linsenelektrodens3>>} stem of a formed on a polyimide film 30 of aluminum mesh 31 with rectangular openings 9 of 0.5 mm + ^ χ 0.54 mm. The second lens electrode system consists of a grid of nickel strips 32, shown horizontally in the drawing, with a width of 0.26 mm. The permeability of the color selection means is again about 50 %. The refocusing effect of this embodiment of the color selection means is analogous to that of the embodiment described with reference to FIG. 4 when, during operation of the tube, the grid 31 has a potential of about 23 kV and the strips 32 a potential of about 25 kV at a potential of the screen 6 lead from about 25 kV. An advantage of the color selection means of FIG. 5 over those of FIG. 4 is that the film 30 contributes significantly to the mechanical strength of the color selection means. An additional stiffening

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- rr-

layer on the strip 32 or the grid 31 is then not absolutely necessary.

Patent claims;

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ORIGINAL INSPECTED

Claims (1)

Claims: ^ 7 O O 616 Cl.) Process for the production of a color picture tube containing an electrode system for generating in an evacuated envelope at least two electron beams, a screen that lights up with a multitude of different colors Areas is covered and a short distance in front of the screen arranged color selection means, with the help of each Electron beam illuminating areas of a specific color are assigned, this color selection means being a contain first and a second lens electrode system and wherein a lens electrode belonging to the first system is connected via an insulating body to a lens electrode belonging to the second system, characterized in that that an electrically insulating film is used as the starting point for the production of the color selection means which on the one hand a first lens electrode system and on the other hand a second lens electrode system is formed, while the desired openings in the color selection means are obtained by localizing the insulating film is etched through. 2. The method according to claim 1, characterized in that for the production of the color selection means of a two-sided with a metal layer coated insulating film is assumed, of which the one metal layer locally to Formation of a first lens electrode system and the other metal layer locally to form a second lens electrode system is etched away. 3. The method according to claim 1, characterized in that at least one of the lens electrode systems directly by depositing metal on the foil. A. The method according to claim 1, 2 or 3, characterized in that at least one of the lens electrode systems mechanically is stiffened by the fact that an additional metal layer is attached. pm 8273 709829/0720 _ ORIGINAL INSPECTED 5. The method according to claim 1, 2, 3 or 4, characterized in that that on one side of the insulating film, a lens electrode system is formed, which consists of a provided with openings arranged in rows metal coating that on the other side of the insulating Foil a lens electrode system is formed, which consists of a metal grid interconnected between the said openings positioned strips, and that the film at least at the points of said Openings is cut through. 6. The method according to claim 1, 2, 3 or 4, characterized in that that on one side of the insulating film, a lens electrode system is formed, which consists of a first metal grid of electrically connected strips that is on the other side of the insulating film a lens electrode system is formed, which is electrically connected to one another from a second metal grid Strip consists, with the second grid crossing the first grid, and that then the film between the to the same Strips belonging to the grid is etched through. 7. The method according to any one of the preceding claims, characterized in that the insulating film consists of a glass film consists. 8. The method according to any one of claims 1 to 6, characterized in that that the insulating film consists of a plastic film. 9. The method according to any one of claims 1 to 6, characterized in that that the insulating film consists of a polyimide film. 10. Color picture tube produced by the method according to one of the preceding claims is made. , HN ₈₂₇₃ ^ ⁹⁸²⁹ ^ -14- 11. Color picture tube contained in an evacuated envelope Means for generating a number of electron beams illuminating a screen with a plurality of different colors Areas and color choices with a variety of openings with the help of which each electron beam lights up Areas of a certain color is assigned, these color selection means a first and a second Containing lens electrode system, and wherein a lens electrode belonging to the first system by means of an insulating body connected to a lens electrode belonging to the second system is characterized in that said insulating body consists of at least one of the locations of said openings perforated foil consists of an electrically insulating material. 12. Color picture tube according to claim 11, characterized in that that the first lens electrode system consists of a metal coating located on one side of the foil in the form of a Grid with openings arranged in rows, while the second lens electrode system consists of one on top of the other Side of the foil located metal coating in the form of electrically connected strips between the rows of openings are positioned. 13. Color picture tube according to claim 11 or 12, characterized in that that the film is a glass film. 14. Color picture tube according to claim 11 or 12, characterized in that that the film is a plastic film. 15. Color picture tube according to claim 11 or 12, characterized in that that the film is a polyimide film. PHN 8273 709829/0720 ORIGINAL INSPECTED