CA1074852A - Method of manufacturing a post-deflection focusing colour selection electrode - Google Patents
Method of manufacturing a post-deflection focusing colour selection electrodeInfo
- Publication number
- CA1074852A CA1074852A CA269,551A CA269551A CA1074852A CA 1074852 A CA1074852 A CA 1074852A CA 269551 A CA269551 A CA 269551A CA 1074852 A CA1074852 A CA 1074852A
- Authority
- CA
- Canada
- Prior art keywords
- plates
- ridges
- plate
- strip
- colour selection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C29/00—Joining metals with the aid of glass
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
- C03C8/02—Frit compositions, i.e. in a powdered or comminuted form
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/80—Arrangements for controlling the ray or beam after passing the main deflection system, e.g. for post-acceleration or post-concentration, for colour switching
- H01J29/81—Arrangements for controlling the ray or beam after passing the main deflection system, e.g. for post-acceleration or post-concentration, for colour switching using shadow masks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
- H01J9/142—Manufacture of electrodes or electrode systems of non-emitting electrodes of shadow-masks for colour television tubes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
- Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
Abstract
ABSTRACT:
The invention relates to a method of manufacturing a cathode ray tube for displaying coloured pictures, in particular the colour selection means, which are manufactured from single plates which are secured together with the interposition of an insulator so that the plates do not contact each other and in which at least one of the plates, prior to the plates being secured together, is provided with a relief pattern which is composed of substantially parallel ridges between which a number of strip-shaped regions are present in which the plate(s) has (have) a much smaller thickness than at the area of the ridges and the material of said strip-shaped regions is removed after being secured together. In this manner colour selection means can be obtained with which refocusing in the cathode ray tube and an associated brighter picture can be obtained.
The invention relates to a method of manufacturing a cathode ray tube for displaying coloured pictures, in particular the colour selection means, which are manufactured from single plates which are secured together with the interposition of an insulator so that the plates do not contact each other and in which at least one of the plates, prior to the plates being secured together, is provided with a relief pattern which is composed of substantially parallel ridges between which a number of strip-shaped regions are present in which the plate(s) has (have) a much smaller thickness than at the area of the ridges and the material of said strip-shaped regions is removed after being secured together. In this manner colour selection means can be obtained with which refocusing in the cathode ray tube and an associated brighter picture can be obtained.
Description
PHN 8262 ~ ~
~g7485~ ~
The invention relates to a method of manu-facturing a cathode ray tube for displaying coloured pictures and comprising in an evacuated envelope means ~o generate a number of elec~ron beams~ a display S screen compris;ng a large number of regions luninescing in different colours, and colour selection means com-prising a large number of apertures which associate each electron beam with luminescent regions of one colour,: :~
which colour selection means comprise electrodes to Form lU an electron lens in each aperture.
The invention also relates to a cathode ray tube manufactured according to this method and tho the ~:.
colour selection means as used in such a cathode ray tube.
Such a cathode ray tube of the reFocusing ; 15 type is known From the United States Patent SpeciFication 3,398,309 which issued to The Rauland Corporation on ~ .
August 20, 1968. The object of refocusing is to increase the br~ghtness of the displayed plcture by increasing the transmission of the colour selection means. In tubes 2D wl~hout reFocusing a very great part, for example 80 to ~ 85%, of the electrons is intercepted by the so-called :n shadow mask. By the use of refocusing the apertures in the colour selection means can be enlarged since as a result Qf the focusing in the apertures the electron . .
s ' " .:
~3 74~5 Z PHN 8262 spots on the screen are considerably smaller than the apertures so that in spite of the increased si~e of aperture sufPicient landing tolerance exists.
The electron lens which is formed in the apertures of the shadow mask of the known tube is of the unipotential type as a result of which a rather great voltage difference is reqwired between the electrodes which form the lens.
Another refocusing tube is described in the United States Patent Specification 2,728,024 which issued to Radio Corporation of America on December 20, 195~. In this tube the electron beams pass successively through two grids which consist of parallel conductors. The conductors associated with different grids are at right angles to each other. The result of this is that the electron beams are successively focused by two electron-optical cylinder lenses which are rotated 90 relative to each other. As a resul~ of the action of both lenses together, the electron beams are focused in one direction and are de-focused ln a direction at right angles thereto.
Anokher drawback of this known tube is that a rather large voltage difference for the focusing is necessary. In addition, both grids do not form a mechani-cal unit so that the vibration of the grid wires presents ~ -~
great problems. In addition it is necessary for the dis-play screen to be flat.
It is the object of the invention to provide ' a method of manufacturing an improved cathode ray tube ; for displaying coloured pictures of the kind ment-ioned in the preamble.
The invention makes it also possible to manu-facture curved plate-shaped colour selection means of a usual s~ze.
'. . ., . . . . . . , .. - . . .. . .
3L~)74~52 PHN 8262 According to the invention, a method of the kind mentioned in the ~irst paragraph is characterized in that the colour selection means are manuFactured from a few metal plates which are secured together with the inter- .
position of insulation material so that the plates do not contact each other, and in which method at: least one of the plates, prior to the plates being secured together, is provided with a pattern which is composed of a number of substantially parallel ridges between which a number of strip-shaped regions are situated in which the plate has a much smaller thickness than at the area of the ridges, the material of said strip-shaped regions being removed after securing the plates together.
As a result of the removal o~ the material of the strip-shaped regions, the ridges remain which form parallel conductive strips and are secured against the other plate(s) while being separated by an insulator. In ; this manner the electrodes for forming an electron lens aré formed.
The colour selection means may be manufactured : :
From two metal plates which one plate is provided with .
apertures and the other p1ate is provided with the said relief pattern, the method including the step of position-ing the plates together in such manner that the apertures . :
~5 on one plate become situated between the ridges of the other plate, colour selection means are thus obtained which are formed from a meta1 plate having the said apertures with conductive strips between the apertures.
: The apertures may be provided in one plate already in an earlier stage of the process or may be obtained by etching together with the removal of the material ~- ~
.
~ 3 ~
- ~ . ; , . ~ . . , .
~LC~7 ~8~jZ PHN 8262 of the strip-shaped regions of the other plates by means of an etching process. The ridges may be provided on two sides of ; the plate or only on one side which may then be remote from the other plate or may iust be arranged against it.
When the colour selection means according to the invention are formed from two plates which are both provided with the said relief pat~ern and the plates are secured to-gether in such manner that the ridges enclose an angle of approximately 90 with respect to each other, then, after removing the strip-shaped regions, colour sèlection means are formed in this manner which are formed from a grid con-sisting o~ two sets of substantially parallel conductors which cross each other, which conductors are insulated from each other at the crossings and in which ~he conductors of ; 15 each set may be mutually interconnected. In this manner, by applying a voltage difference between the sets, a quadrupole lens is formed in each aperture of the said colour selection means. Since the electric field is at right angles to the - electron pathg quadrupole lenses are very strong as compared with the said cylinder lenses so that much lower voltages than in said cylinder lenses will suffice. That a quadrupole lens focuses in one direction and defocuses in a direction at right angles thereto is no drawback in principle when all quadrupole have the same orientation. Therefore, the .. .
luminescent regions of the display screen preferably have the shape of substantially parallel strip the longitudinal direc-tion of which is substantially parallel to the de~ocuslng direction of quadrupole lenses.
,, . ." ...................................................................... , The relief pattern is provided in the plates by means of known technologies~ for example, etching, rolling, spark ero~ion and moulding.
.. ~
; - 4 -' ~C)~9~5 Z PHN 8262 The great advantage of such a method accordiny to the invention is that the individual plates have a great rigidity so that colour selection means of large dimensions and a curved shape can be manufactured. Moreoverg the con-ductive strips are provided against the other plate at the desired distance from each other.
The embodiment of the method is that in which the insultation material is glass which is provided on at least one of the plates in the form of glass powder~ aFter which n ;t is converted inbo solid glass by a thermal treatment and the excessive glass, after removing the material of the said strip-shaped regions, is removed.
The glass powder may be provided on the plates, for example, by spraying, silk-screening, settling ~depositing) or by means of tape containing glass powder and known com-mercially as Vitta. In order to minimize the quality oP
excessive glass between these p~ates, for example, the area not to be coated may be covered with a template during spraying and depositing.
An elegant method of providing the glass is that in which one of the plates which is provided with a relief pattern ~s then covered with an insulator so that only the ridges remain uncovered~ which ridges are then coated with glass powder electrophoretically, after which the insulator is re-moved, which glass powder is converted into solid glass by a thermal treatment, after which the plate with the covered ` ridges is secured against a second plate. As suitable insula-tors may be used inter alia methacrylate resins, polyimides, beeswax or paraffin.
The electrophoretic coating with glass powder is preferably carried out in an e1ectrophoresis bath which contains as a carrier liquid an alcohol~ preferably ' , - 5 -, ,, . , .. , , ,, . . , ; , . -. , , , ,, , ~ , ,. . i . . :
z methanol, in which the glass powder is suspended.
The removal of the excessive glass may be carried ou~ by means of powder blasting from both sides in which the glass on the apertured plate or the glass at the crossings of the grid is in the "shadow" of the conductive strips. Excens-s;ve glass is the glass which has no adhering and insulating functions, for example, the glass which is present on the conductors, not at the crossings.
Other very suitable insulators for the method according to the invention are re~ractory synthetic materials so that another preferred embodiment of the method according to the invention is characterized in that a refractory synthetic foil ;s provided between the plates as an insulator and that the excessive synthet;c material (no adhering and insulat;ng function) and the material of the said regions are removed.
The synthetic material should be refractory because the cathode ray tube reaches temperatures up to 500C during securing the display window to the oone and during evacuating.
The synthetic foil may also be used read as an adhesive for securing the plates together, when the synthetic fo;l is wetted at least on one side with an adhesive for the synthetic material of which the foil consists before it ;s provided between the plates. A number of synthetic materials adhere only after they have been subjected to a thermal treat-ment. In said treatment gases are formed so that it is recommendable to provide at least one of the plates with a number of small apertures for the escape of the sa;d gases.
Very suitable synthetic materials are the polyi-mides of which the poly~mide of 4-4' d;aminod;phenyl ether and 1-~-4-5 benzenetetracarbonic ac;d dianhydr;de .
, . '' ~ 3L~7 ~35 Z
proves to give particularly good satisfaction and is available inter alia in a foil form under the name of Kapton which is a registered trade mark of Dupont.
; The plates may not contact each other even when the intermediate insulation materials become soft and must remain insulated relative to each other. This can be done by securing them together at the desired distance in a very defined manner. It can be done in a very simple manner by keeping the plates at the said desired distance ; lO by means of spacing elements. The spacing elements may, for example, be spherical and bear between the ridges.
The provision of an insulating layer may also be done quite differently. IF at least one of the plates consists of aluminium at a surface, which sur~ace is at least partly anodized, a suitable insulator layer of A1203 is obtained. -When the material of the strip-shaped regions is not entirely removed, edges are Formed at the ridges which provide a screening of the insulation material for the electron beams and/or possible barium parts `
originating from a getter.
; Fmbodiments of the invention will now be described by the way of example with reference to the diagrammatic drawings in which:
Figure 1 shows a cathode ray ~ube manuFactured by a method embodying to the invention, Figure 2 shows the operation of a quadrupole lens denoted diagrammatically, Figures 3a, b and c show the manufacture in ` 30 steps of a plate having a relief pattern, Figure 4 shows ~wo plates as illustrated in Figure 3c secured together, . ~
~1374~3S~ ~
F;gure 5a shows a part of a cross grid su;table for colour selection means, Figure 5b shows the operation of such a cross grid, Figure 6a and 6b and 7a, 7b and 7c show a few other possible relief patterns, Figure 8 shows diagrammatically a method of electro-phoretic coating with glass powder, ~ .
Figures 9 and 10 show the manufacture of a part ofa cross grid by means of glass powder, Figure 11 shows an apertured relief plate, Figures 12 and 13 show spacing elements, Figure 14 shows a suction plate for securing the plates together, Figures 15a, b and c show an anodized aluminium plate and, I Fiyures 16a and b show an apertured plate provided with conductive strips.
. The cathode ray tube shown in Figure 1 comprises :~, a glass envelope 1, means 2 to generate three electron beams 3, 4 and 5, a display screen 6, colour selection means 7 and deflection coils 8. The electron beams 3, 4 and 5 are gen~
erated in one plane, the plane of the drawing of Figure 1, and are deflected over the display screen 6 by means of the deflection coils 8. The display screen 6 consists of a large number of phosphor strips luminescing in red, green and blue of approximately 0.13 mm wide, the longitudinal direction of which is at right angles ~o the plane of the drawing of Figure 1. During normal operation of the tube the phosphor strips are vertical and Figure 1 hence is a sectional view of .
3U the tube at right angles to the phosphor strips. The colour ~ ~
~ ,;
. "
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. ~ ~ .. .. .... . . . .. .
~1:37~5Z
selection means 7 comprise a large number o~ apertures 9 which are shown diagrammatically only in Figure 1. The three electron beams 3, 4 and 5 pass through the apertures 9 at a small angle to each other (the so-called colour selection angle) and consequently each impinge only upon phosphor strips of one colour. The ape~tures 9 in the colour selection means 7 are thus very accurately posi-tioned relative to the phosphor strips of the display screen 6.
In the nowadays generally used shadow mask tube, in which the colour selection means consist of a metal plate having circular or slot-like apertures, the electron beams 3, 4 and 5 are not focuses upon passing `~ through the apertures 9. It has been suggested to use lS post deflection focusing by means of a potential difference between the colour selection means 7 and the display screen 6 in which, however, annoying effects of secondary electrons !
are experienced.
In a cathode ray tube manufactured by means of one of the methods according to the invention, a quadrupole lens is ~ormed in each aperture o~ the colour selection means 7. Flgure 2 shows diagrammatically such a quadrupole lens with a part of the colour selection means 7 and one of the apertures 9. The potential variation along the edge
~g7485~ ~
The invention relates to a method of manu-facturing a cathode ray tube for displaying coloured pictures and comprising in an evacuated envelope means ~o generate a number of elec~ron beams~ a display S screen compris;ng a large number of regions luninescing in different colours, and colour selection means com-prising a large number of apertures which associate each electron beam with luminescent regions of one colour,: :~
which colour selection means comprise electrodes to Form lU an electron lens in each aperture.
The invention also relates to a cathode ray tube manufactured according to this method and tho the ~:.
colour selection means as used in such a cathode ray tube.
Such a cathode ray tube of the reFocusing ; 15 type is known From the United States Patent SpeciFication 3,398,309 which issued to The Rauland Corporation on ~ .
August 20, 1968. The object of refocusing is to increase the br~ghtness of the displayed plcture by increasing the transmission of the colour selection means. In tubes 2D wl~hout reFocusing a very great part, for example 80 to ~ 85%, of the electrons is intercepted by the so-called :n shadow mask. By the use of refocusing the apertures in the colour selection means can be enlarged since as a result Qf the focusing in the apertures the electron . .
s ' " .:
~3 74~5 Z PHN 8262 spots on the screen are considerably smaller than the apertures so that in spite of the increased si~e of aperture sufPicient landing tolerance exists.
The electron lens which is formed in the apertures of the shadow mask of the known tube is of the unipotential type as a result of which a rather great voltage difference is reqwired between the electrodes which form the lens.
Another refocusing tube is described in the United States Patent Specification 2,728,024 which issued to Radio Corporation of America on December 20, 195~. In this tube the electron beams pass successively through two grids which consist of parallel conductors. The conductors associated with different grids are at right angles to each other. The result of this is that the electron beams are successively focused by two electron-optical cylinder lenses which are rotated 90 relative to each other. As a resul~ of the action of both lenses together, the electron beams are focused in one direction and are de-focused ln a direction at right angles thereto.
Anokher drawback of this known tube is that a rather large voltage difference for the focusing is necessary. In addition, both grids do not form a mechani-cal unit so that the vibration of the grid wires presents ~ -~
great problems. In addition it is necessary for the dis-play screen to be flat.
It is the object of the invention to provide ' a method of manufacturing an improved cathode ray tube ; for displaying coloured pictures of the kind ment-ioned in the preamble.
The invention makes it also possible to manu-facture curved plate-shaped colour selection means of a usual s~ze.
'. . ., . . . . . . , .. - . . .. . .
3L~)74~52 PHN 8262 According to the invention, a method of the kind mentioned in the ~irst paragraph is characterized in that the colour selection means are manuFactured from a few metal plates which are secured together with the inter- .
position of insulation material so that the plates do not contact each other, and in which method at: least one of the plates, prior to the plates being secured together, is provided with a pattern which is composed of a number of substantially parallel ridges between which a number of strip-shaped regions are situated in which the plate has a much smaller thickness than at the area of the ridges, the material of said strip-shaped regions being removed after securing the plates together.
As a result of the removal o~ the material of the strip-shaped regions, the ridges remain which form parallel conductive strips and are secured against the other plate(s) while being separated by an insulator. In ; this manner the electrodes for forming an electron lens aré formed.
The colour selection means may be manufactured : :
From two metal plates which one plate is provided with .
apertures and the other p1ate is provided with the said relief pattern, the method including the step of position-ing the plates together in such manner that the apertures . :
~5 on one plate become situated between the ridges of the other plate, colour selection means are thus obtained which are formed from a meta1 plate having the said apertures with conductive strips between the apertures.
: The apertures may be provided in one plate already in an earlier stage of the process or may be obtained by etching together with the removal of the material ~- ~
.
~ 3 ~
- ~ . ; , . ~ . . , .
~LC~7 ~8~jZ PHN 8262 of the strip-shaped regions of the other plates by means of an etching process. The ridges may be provided on two sides of ; the plate or only on one side which may then be remote from the other plate or may iust be arranged against it.
When the colour selection means according to the invention are formed from two plates which are both provided with the said relief pat~ern and the plates are secured to-gether in such manner that the ridges enclose an angle of approximately 90 with respect to each other, then, after removing the strip-shaped regions, colour sèlection means are formed in this manner which are formed from a grid con-sisting o~ two sets of substantially parallel conductors which cross each other, which conductors are insulated from each other at the crossings and in which ~he conductors of ; 15 each set may be mutually interconnected. In this manner, by applying a voltage difference between the sets, a quadrupole lens is formed in each aperture of the said colour selection means. Since the electric field is at right angles to the - electron pathg quadrupole lenses are very strong as compared with the said cylinder lenses so that much lower voltages than in said cylinder lenses will suffice. That a quadrupole lens focuses in one direction and defocuses in a direction at right angles thereto is no drawback in principle when all quadrupole have the same orientation. Therefore, the .. .
luminescent regions of the display screen preferably have the shape of substantially parallel strip the longitudinal direc-tion of which is substantially parallel to the de~ocuslng direction of quadrupole lenses.
,, . ." ...................................................................... , The relief pattern is provided in the plates by means of known technologies~ for example, etching, rolling, spark ero~ion and moulding.
.. ~
; - 4 -' ~C)~9~5 Z PHN 8262 The great advantage of such a method accordiny to the invention is that the individual plates have a great rigidity so that colour selection means of large dimensions and a curved shape can be manufactured. Moreoverg the con-ductive strips are provided against the other plate at the desired distance from each other.
The embodiment of the method is that in which the insultation material is glass which is provided on at least one of the plates in the form of glass powder~ aFter which n ;t is converted inbo solid glass by a thermal treatment and the excessive glass, after removing the material of the said strip-shaped regions, is removed.
The glass powder may be provided on the plates, for example, by spraying, silk-screening, settling ~depositing) or by means of tape containing glass powder and known com-mercially as Vitta. In order to minimize the quality oP
excessive glass between these p~ates, for example, the area not to be coated may be covered with a template during spraying and depositing.
An elegant method of providing the glass is that in which one of the plates which is provided with a relief pattern ~s then covered with an insulator so that only the ridges remain uncovered~ which ridges are then coated with glass powder electrophoretically, after which the insulator is re-moved, which glass powder is converted into solid glass by a thermal treatment, after which the plate with the covered ` ridges is secured against a second plate. As suitable insula-tors may be used inter alia methacrylate resins, polyimides, beeswax or paraffin.
The electrophoretic coating with glass powder is preferably carried out in an e1ectrophoresis bath which contains as a carrier liquid an alcohol~ preferably ' , - 5 -, ,, . , .. , , ,, . . , ; , . -. , , , ,, , ~ , ,. . i . . :
z methanol, in which the glass powder is suspended.
The removal of the excessive glass may be carried ou~ by means of powder blasting from both sides in which the glass on the apertured plate or the glass at the crossings of the grid is in the "shadow" of the conductive strips. Excens-s;ve glass is the glass which has no adhering and insulating functions, for example, the glass which is present on the conductors, not at the crossings.
Other very suitable insulators for the method according to the invention are re~ractory synthetic materials so that another preferred embodiment of the method according to the invention is characterized in that a refractory synthetic foil ;s provided between the plates as an insulator and that the excessive synthet;c material (no adhering and insulat;ng function) and the material of the said regions are removed.
The synthetic material should be refractory because the cathode ray tube reaches temperatures up to 500C during securing the display window to the oone and during evacuating.
The synthetic foil may also be used read as an adhesive for securing the plates together, when the synthetic fo;l is wetted at least on one side with an adhesive for the synthetic material of which the foil consists before it ;s provided between the plates. A number of synthetic materials adhere only after they have been subjected to a thermal treat-ment. In said treatment gases are formed so that it is recommendable to provide at least one of the plates with a number of small apertures for the escape of the sa;d gases.
Very suitable synthetic materials are the polyi-mides of which the poly~mide of 4-4' d;aminod;phenyl ether and 1-~-4-5 benzenetetracarbonic ac;d dianhydr;de .
, . '' ~ 3L~7 ~35 Z
proves to give particularly good satisfaction and is available inter alia in a foil form under the name of Kapton which is a registered trade mark of Dupont.
; The plates may not contact each other even when the intermediate insulation materials become soft and must remain insulated relative to each other. This can be done by securing them together at the desired distance in a very defined manner. It can be done in a very simple manner by keeping the plates at the said desired distance ; lO by means of spacing elements. The spacing elements may, for example, be spherical and bear between the ridges.
The provision of an insulating layer may also be done quite differently. IF at least one of the plates consists of aluminium at a surface, which sur~ace is at least partly anodized, a suitable insulator layer of A1203 is obtained. -When the material of the strip-shaped regions is not entirely removed, edges are Formed at the ridges which provide a screening of the insulation material for the electron beams and/or possible barium parts `
originating from a getter.
; Fmbodiments of the invention will now be described by the way of example with reference to the diagrammatic drawings in which:
Figure 1 shows a cathode ray ~ube manuFactured by a method embodying to the invention, Figure 2 shows the operation of a quadrupole lens denoted diagrammatically, Figures 3a, b and c show the manufacture in ` 30 steps of a plate having a relief pattern, Figure 4 shows ~wo plates as illustrated in Figure 3c secured together, . ~
~1374~3S~ ~
F;gure 5a shows a part of a cross grid su;table for colour selection means, Figure 5b shows the operation of such a cross grid, Figure 6a and 6b and 7a, 7b and 7c show a few other possible relief patterns, Figure 8 shows diagrammatically a method of electro-phoretic coating with glass powder, ~ .
Figures 9 and 10 show the manufacture of a part ofa cross grid by means of glass powder, Figure 11 shows an apertured relief plate, Figures 12 and 13 show spacing elements, Figure 14 shows a suction plate for securing the plates together, Figures 15a, b and c show an anodized aluminium plate and, I Fiyures 16a and b show an apertured plate provided with conductive strips.
. The cathode ray tube shown in Figure 1 comprises :~, a glass envelope 1, means 2 to generate three electron beams 3, 4 and 5, a display screen 6, colour selection means 7 and deflection coils 8. The electron beams 3, 4 and 5 are gen~
erated in one plane, the plane of the drawing of Figure 1, and are deflected over the display screen 6 by means of the deflection coils 8. The display screen 6 consists of a large number of phosphor strips luminescing in red, green and blue of approximately 0.13 mm wide, the longitudinal direction of which is at right angles ~o the plane of the drawing of Figure 1. During normal operation of the tube the phosphor strips are vertical and Figure 1 hence is a sectional view of .
3U the tube at right angles to the phosphor strips. The colour ~ ~
~ ,;
. "
: '~
. ~ ~ .. .. .... . . . .. .
~1:37~5Z
selection means 7 comprise a large number o~ apertures 9 which are shown diagrammatically only in Figure 1. The three electron beams 3, 4 and 5 pass through the apertures 9 at a small angle to each other (the so-called colour selection angle) and consequently each impinge only upon phosphor strips of one colour. The ape~tures 9 in the colour selection means 7 are thus very accurately posi-tioned relative to the phosphor strips of the display screen 6.
In the nowadays generally used shadow mask tube, in which the colour selection means consist of a metal plate having circular or slot-like apertures, the electron beams 3, 4 and 5 are not focuses upon passing `~ through the apertures 9. It has been suggested to use lS post deflection focusing by means of a potential difference between the colour selection means 7 and the display screen 6 in which, however, annoying effects of secondary electrons !
are experienced.
In a cathode ray tube manufactured by means of one of the methods according to the invention, a quadrupole lens is ~ormed in each aperture o~ the colour selection means 7. Flgure 2 shows diagrammatically such a quadrupole lens with a part of the colour selection means 7 and one of the apertures 9. The potential variation along the edge
2~ of aperture 9 is denoted by ~a ~~ +~ - in such manner that a quadrupole field is formed. The electron beam which passes through the aperture 9 is focused in the horizon-tally drawn plane and is defocused in the vertically drawn plane so that, when the display screen is exactly in the horizontal focus, the electron spot 10 is formed. It is recommendable not to focus exactly on the display screen 6 as a result of which a slightly wider electron spot is ~
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.
3~7 ~35 Z
obtained. It is only a minor effect on the focusing when the electron beam passes through the aperture 9 at a small angle; as a result of this the colour selection of the three electron beams 3, 4 and 5 takes place in a manner qu;te analogous to that in the known shadow mask tube. As a result of this strong focusing, however, the aperture 9 may be much larger than in the known shadow mask tube so far more electrons impinge upon the display screen 6 and a brighter picture is obtained. The defocusing in the vertical direction need not be any objection when the phosphor strips are used which are parallel to the longitudinal direction of the spot 10.
Figures 3a, b and c diagrammatically show a plate provided with a relief and used in the invention can be obtained by etching. Figure 3a is a plan view of a part of such a plate, Figure 3b is the associated sectional view and Figure 3c is a perspective view of the result. The parts of a metal plate 11 which may not be etched away are covered with an etchant-resistant material 12 which is provided on the plate in the desired pattern. A relief pattern as shown in Figure 3c is now obtained by etching, in which a number of ridges 13 (for example approximately 100 /um thick) are separated by a number of strip-shaped regions 14 having a smaller thickness (~or example 30 /um).
The relief pattern can also be provided by moulding it in ~he plate, by spark erosion or during a rolling process.
In Figure 4, two of such plates as in Figure 3c are secured together with the ridges 13 facing each other.
It is also possible ~o secure the plates toge~her with the ridges remote from each other. In certain cases this may even be more favourable since the plates can more easily --be bent in a direction at right angles to the direction -... ~ , . .... . .. . , :.
sz of the ridges. The connection is ef~ected by means of an insulator 15 and in such manner that the plates do not contact each other. How this can be done will be explained herein-after. ey etching away the strip-shaped regions 14 a cross grid as is shown in Figure 5a is obtained which consists of two sets of parallel conductive strips 16 and 17 which are separated from each other at the crossing by an insulator 15 and which are secured together. The provision of the in-sulator 15 will be described hereinafter.
Figure 5b shows the operation of such a cross grid. The colour selection means 7 consist of two sets o~F
parallel conductive strips. Of the first set are shown the horizontally drawn conductive strips 17 and of the second set are shown the vertically drawn conductive strips 16.
Together they determine one of the apertures 9. The strips 16 are insulated from the strips 17 by means of an insulator 15. On the display screen 6 the three phosphor strips associated with the aperture 9 are ;ndicated by R (red), (green), and B (blue). In the Figure only a few rays of the central electron beam 4 are shown which ~orm electron spot 10 on the phosphor strip G. The horizontal conductive strips 17 are connected together and are at a higher potential than the interconnected conductive strips 15 so that the quadru-pole lens shown diagrammatlcally in Figure 2 is ~formed in each aperture 9.
- The following results were obtained with colour selection rr~ans as shown in Figure 5 mounted in a display tube and having conductive strips 16 and 17 having a width o~ 0.2~ mm and a mutual pitch of 0.80 rrlm so that the -:
transmission of the colour selection rrleans was appraximately 50%. With a potential of the display screen 6 of 25 kV and a potential of the horizontal conductors of 25,5 kV and of ~ .
~7~ 5Z
PHN 82~2 the vertical conductors of 24,5 kV, the focal distance of the quadrupole lenses was 18.0 mm in the centre of the display screen with perpendicular incidence and was 12.7 mm with an incidence at 37 in the corners of the display screen. The distance of the colour selection means 7 to the display screen 6 was 15 mm in the centre and 10 mm at the edge so that the focus of the quadrupole lens was every-where just slightly beyond the display screen. As a result o~ this a so-called ~ocus ring was not visible on the dis-play screen. The electron spots are 0.10 mm wide in the centre o~ the display screen and 0.09 mm in the corners.
A suitable width of phosphor strips R, G and B was found to be 0.13 mm, the remainder of the surface of the display screen may or may not be coated with a light-absorbing mater-ial.
Figures 6a and 6b and Figures 7a, b and c are sectional views of a number of possible shapes of relief patterns. With the relief pattern shown in Figure 7a, strip-shaped conductors as shown in Figure 7b can be obtained with edges 20. These edges are chosen to be so that the ~`
electron beams passing through the apertures 9 do not touch the insulation material so that charging o~ the insulator at the crossings by the electron beam is prevented. Besides it can be prevented that barium originating from a barium getter present in the cathode ray tube deposits on the insulation material and causes shortcircuit there.
A particularly suitable insulator 15 both to secure the sets o~ conductive strips 16 and 17 together and to connect a set ~f conductive strips to an apertured metal plate is glass. Suitably the glass is provided in powder form and is then converted into solid glass by heating.
The glass powder may be provided by spraying it on thle plate, the places not to be coated bein~ screened b~ means of a - . - -- . i . . : - ~ ,: - -.
L 1374~3~2 template. The glass powder may alternatively be provided : to means of a silk-screening process, by settling (deposit-ing in a bath) or by securing the glass powder against the metal plate by means of a tape comprising glass powder.
It is alternatively possible to provide glass in foil form and to heat the plates with the intermediate foi1 so that ~ adhesion of the glass to the plate occurs. After removing - the material of the strip-shaped regions, the excessive glass is removed, for example, by etching or powder blast-ing.
Figure 8 shows diagrammatically a par-ticularly suitable method of providing the glass powder 18, namely el~ectrophoretic coating. An electrophoresis bath 21 contains a liquid, preferably an alcohol 23 (for example methanol) in which glass powder 18 is suspended. Two electrodes 22 and 24 are in the bath. Electrode 24 is formed by a ridged plate which comprises a relief and is to be coated with glass powder 18. The glass particles are changed electrically in that ions of a suitable electrolyte present in the bath adhere to the glass particles. Depen-dent on the positive or negative charge, a given voltage is applied between the electrodes 22 and 24 so that the glass particles 18 will move towards the electrode 24. The parts not to be coated are covered with a layer of suitable insulator 199 for example, methacrylate resin, polyimide, beeswax or paraffin. With a voltage between the electrodes 22 and ~4 of approximately 100 volts and a distance between the electrodes of 1 cm, a layer of glass powder 18~ thick-ness approximately 60 /um, would be deposited on an elec-trode surface of 10 sq. cm in 90 seconds.
By etching away3 dissolvdng, evaporating or removing the insulator 19 in a different manner and con-verting the glass powder into solid glass by heating, a .~ .
`` ~IL~37~3S~2 ridged plate is obtained which comprises a re1ief and has a layer of solid glass on the ridges. Such a plate may then be placed against an apertured plate or a~ainst another plate comprising a relief, as has been described above. When the insulator 19 is a polyimide, it can be rleadily dissolved in a solution of approximately 10 normal solution lye, prefer-ably KOH, or in N2H4. H20 (hydrazine hydrate).
In Figure 9, two plates comprising a relief and coated with glass in the above-described manner are provided one on top of the other. The shape of the relief pattern is approximately equal to that shown in Figure 7a.
The plates are secured together by heating. By removing the strip-shaped regions 14, for example by etching, the grid is obtained as is shown in Figure 10. It is alter-natively possible to secure the plates together with the ridges remote from each other instead of, as in Figure 9, with the ridges facin~seach other. In that case the glass powder should be provided on the surfaces 25 not comprising a relief, may also be done non-electrophotoretically.
The securing together o~ the plates when glass is used as an insulator will as a rule be carried out at elevated temperature. Dependent on the kind of glass and the material oF the plates used, this will be done in a reducing or oxidizing atmosphere. In order to contact the reducing or oxidizing atmosphere with the insulator material it is recommendable to provide the plate(s) with a number of apertures 26 as is shown in Figure 11. Said apertures 26 are also desired when a synthetlc foil wetted with an adhesive is used as an insulator, but in this case they are desired for causing any gases formed during heating to flow away. Said gases occur notably when a foil is used of ' "
.
-~7~35~
a polyimide of 4--4' diaminodiphenyl ether and 1, 2, 4, 5 benzenetetracarbonic acid dianhydride which is wetted with a solution of a polyimide of the same materials, in which gases are formed during polymerisation in which the poly-amide is converted into the polyimide.
After folding the plates together they may not contact each other. For that purpose, during assembly so-called suction plates may be used the operation of which will be explained with reference to Figure 14. It consists of a stain1ess steel plate 34 of a fen cms thickness which .. has been made tension free and has the correct shape and flatness within the desired accuracy. The suction plate comprises a number o~ slots 35 which can be made to communi-cate with a vacuum line 36 via a duct. The plates secured one on top of the other are sucked on such suction plates and provided on each other at the desired distance, with . . .
the interposition of the insulator 15, and heated to a ..
temperature which is sufficiently high for the insulation material so that the adhesion is produced. ...
As shown in Figures 12 and 13 in two parts of :
sectional views through two plates 27 and 28 comprising a relief and secured together at an angle of 90, the correct distance can also be obtained by using spacing elements between said plates in the form of a sphere 29 or a rod 30, rPspectively, which spheres or rods are removed together with the strip shaped regions.
Figure 15a is a sectional view of a part of a plate having a relief pattern which consists at least at surface of aluminium. By anodizing the parts 31 of the : 3~ ridges 13 consisting of aluminium at least at the surface, said aluminium is converted at that area into an A1203 layer 31 which, as is known, is an insulator. Another plate :.
~LO 7 ~3~jZ PHN 8262 32 is secured against the anodized layers and the strip-shaped regions are removed again (Figure 15c). Said plate 32 may also be a plate having a relief pattern or may be an apertured plate. In order to ensure the screening of the electron beams from the earth's magnetic field, at least one of the plates of the colour selection means 7 preferably consists of a ferro-magnetic material, for example Fe, Co, Ni or alloys of or with said metals.
Figures 16a and b show a part of colour selection means which comprise a plate 33 having apertures 9. A plate having a relief is secured against said plate by means of an insulator 15 so that the ridges 13 become situated between the ~ .
apertures 9. By removing the strip-shaped regions 14 the .
colour selection means as shown in Figure 16a are obtained.
The operation thereof is shown in Figure 16b. The three phosphor strips associated with the aperture 9 are shown on the display screen 6 in the same manner as in Figure 5b.
; The conductive strips 17 are connected together and are at a lower potential~than the plate 33 so that the desired . 20 quadrupole lens is formed in the aperture as a result of which the electron beam is displayed as a spot 10. .
A display screen for a tube according to the in-vention can be manu~actured by means of a known exposure method in which the colour selection means are displayed on ~S a photosensitive layer on a window portion of the tube. Small variations in the distance between the conduc~ive strips of set 16 cause defects in the width of the phosphor strips. ~ .
The method according to the invention prevents such variations in that during the manufacture of the colour selection rneans the distance between the conductive strips (ridges 13) is ~.
fixed by the strip-shaped regions 14.
. In connection with the great transrnission of the .
. .
- 16 - . :
,5zl colour selection means according to the invention, the exposure method used should be suitable to display the aper-ture 9 in a conslderably narrowed manner to get the phosphor strips with the right width. An exposure method suitable for this purpose uses two or more light sources at some distance from each other, as described in German patent application 2,2~8,878 by Sony and published on April 19, 1973. Of course, a tube according to the invention is also excellently suitable for so-called electronic exposure in which the sensitive layer on the window portion is "exposed" by means of an electron beam.
It will be obvious that constructions in which more than two plates are secured together with the inter-position of an insulator also fall within the scope of the present invention. According to the method of the invention, for example, not one plate but two plates having a relief pattern may be secured against a plate having apertures 33 as shown in Figure 16a, so that a set of parallel strips is formed on two sides of the apertured plate. Very symmetrical quadrupole lenses can be obtained with such a construction.
- 17 ~
. ' '`""~
' . . .. .
.. . .
obtained. It is only a minor effect on the focusing when the electron beam passes through the aperture 9 at a small angle; as a result of this the colour selection of the three electron beams 3, 4 and 5 takes place in a manner qu;te analogous to that in the known shadow mask tube. As a result of this strong focusing, however, the aperture 9 may be much larger than in the known shadow mask tube so far more electrons impinge upon the display screen 6 and a brighter picture is obtained. The defocusing in the vertical direction need not be any objection when the phosphor strips are used which are parallel to the longitudinal direction of the spot 10.
Figures 3a, b and c diagrammatically show a plate provided with a relief and used in the invention can be obtained by etching. Figure 3a is a plan view of a part of such a plate, Figure 3b is the associated sectional view and Figure 3c is a perspective view of the result. The parts of a metal plate 11 which may not be etched away are covered with an etchant-resistant material 12 which is provided on the plate in the desired pattern. A relief pattern as shown in Figure 3c is now obtained by etching, in which a number of ridges 13 (for example approximately 100 /um thick) are separated by a number of strip-shaped regions 14 having a smaller thickness (~or example 30 /um).
The relief pattern can also be provided by moulding it in ~he plate, by spark erosion or during a rolling process.
In Figure 4, two of such plates as in Figure 3c are secured together with the ridges 13 facing each other.
It is also possible ~o secure the plates toge~her with the ridges remote from each other. In certain cases this may even be more favourable since the plates can more easily --be bent in a direction at right angles to the direction -... ~ , . .... . .. . , :.
sz of the ridges. The connection is ef~ected by means of an insulator 15 and in such manner that the plates do not contact each other. How this can be done will be explained herein-after. ey etching away the strip-shaped regions 14 a cross grid as is shown in Figure 5a is obtained which consists of two sets of parallel conductive strips 16 and 17 which are separated from each other at the crossing by an insulator 15 and which are secured together. The provision of the in-sulator 15 will be described hereinafter.
Figure 5b shows the operation of such a cross grid. The colour selection means 7 consist of two sets o~F
parallel conductive strips. Of the first set are shown the horizontally drawn conductive strips 17 and of the second set are shown the vertically drawn conductive strips 16.
Together they determine one of the apertures 9. The strips 16 are insulated from the strips 17 by means of an insulator 15. On the display screen 6 the three phosphor strips associated with the aperture 9 are ;ndicated by R (red), (green), and B (blue). In the Figure only a few rays of the central electron beam 4 are shown which ~orm electron spot 10 on the phosphor strip G. The horizontal conductive strips 17 are connected together and are at a higher potential than the interconnected conductive strips 15 so that the quadru-pole lens shown diagrammatlcally in Figure 2 is ~formed in each aperture 9.
- The following results were obtained with colour selection rr~ans as shown in Figure 5 mounted in a display tube and having conductive strips 16 and 17 having a width o~ 0.2~ mm and a mutual pitch of 0.80 rrlm so that the -:
transmission of the colour selection rrleans was appraximately 50%. With a potential of the display screen 6 of 25 kV and a potential of the horizontal conductors of 25,5 kV and of ~ .
~7~ 5Z
PHN 82~2 the vertical conductors of 24,5 kV, the focal distance of the quadrupole lenses was 18.0 mm in the centre of the display screen with perpendicular incidence and was 12.7 mm with an incidence at 37 in the corners of the display screen. The distance of the colour selection means 7 to the display screen 6 was 15 mm in the centre and 10 mm at the edge so that the focus of the quadrupole lens was every-where just slightly beyond the display screen. As a result o~ this a so-called ~ocus ring was not visible on the dis-play screen. The electron spots are 0.10 mm wide in the centre o~ the display screen and 0.09 mm in the corners.
A suitable width of phosphor strips R, G and B was found to be 0.13 mm, the remainder of the surface of the display screen may or may not be coated with a light-absorbing mater-ial.
Figures 6a and 6b and Figures 7a, b and c are sectional views of a number of possible shapes of relief patterns. With the relief pattern shown in Figure 7a, strip-shaped conductors as shown in Figure 7b can be obtained with edges 20. These edges are chosen to be so that the ~`
electron beams passing through the apertures 9 do not touch the insulation material so that charging o~ the insulator at the crossings by the electron beam is prevented. Besides it can be prevented that barium originating from a barium getter present in the cathode ray tube deposits on the insulation material and causes shortcircuit there.
A particularly suitable insulator 15 both to secure the sets o~ conductive strips 16 and 17 together and to connect a set ~f conductive strips to an apertured metal plate is glass. Suitably the glass is provided in powder form and is then converted into solid glass by heating.
The glass powder may be provided by spraying it on thle plate, the places not to be coated bein~ screened b~ means of a - . - -- . i . . : - ~ ,: - -.
L 1374~3~2 template. The glass powder may alternatively be provided : to means of a silk-screening process, by settling (deposit-ing in a bath) or by securing the glass powder against the metal plate by means of a tape comprising glass powder.
It is alternatively possible to provide glass in foil form and to heat the plates with the intermediate foi1 so that ~ adhesion of the glass to the plate occurs. After removing - the material of the strip-shaped regions, the excessive glass is removed, for example, by etching or powder blast-ing.
Figure 8 shows diagrammatically a par-ticularly suitable method of providing the glass powder 18, namely el~ectrophoretic coating. An electrophoresis bath 21 contains a liquid, preferably an alcohol 23 (for example methanol) in which glass powder 18 is suspended. Two electrodes 22 and 24 are in the bath. Electrode 24 is formed by a ridged plate which comprises a relief and is to be coated with glass powder 18. The glass particles are changed electrically in that ions of a suitable electrolyte present in the bath adhere to the glass particles. Depen-dent on the positive or negative charge, a given voltage is applied between the electrodes 22 and 24 so that the glass particles 18 will move towards the electrode 24. The parts not to be coated are covered with a layer of suitable insulator 199 for example, methacrylate resin, polyimide, beeswax or paraffin. With a voltage between the electrodes 22 and ~4 of approximately 100 volts and a distance between the electrodes of 1 cm, a layer of glass powder 18~ thick-ness approximately 60 /um, would be deposited on an elec-trode surface of 10 sq. cm in 90 seconds.
By etching away3 dissolvdng, evaporating or removing the insulator 19 in a different manner and con-verting the glass powder into solid glass by heating, a .~ .
`` ~IL~37~3S~2 ridged plate is obtained which comprises a re1ief and has a layer of solid glass on the ridges. Such a plate may then be placed against an apertured plate or a~ainst another plate comprising a relief, as has been described above. When the insulator 19 is a polyimide, it can be rleadily dissolved in a solution of approximately 10 normal solution lye, prefer-ably KOH, or in N2H4. H20 (hydrazine hydrate).
In Figure 9, two plates comprising a relief and coated with glass in the above-described manner are provided one on top of the other. The shape of the relief pattern is approximately equal to that shown in Figure 7a.
The plates are secured together by heating. By removing the strip-shaped regions 14, for example by etching, the grid is obtained as is shown in Figure 10. It is alter-natively possible to secure the plates together with the ridges remote from each other instead of, as in Figure 9, with the ridges facin~seach other. In that case the glass powder should be provided on the surfaces 25 not comprising a relief, may also be done non-electrophotoretically.
The securing together o~ the plates when glass is used as an insulator will as a rule be carried out at elevated temperature. Dependent on the kind of glass and the material oF the plates used, this will be done in a reducing or oxidizing atmosphere. In order to contact the reducing or oxidizing atmosphere with the insulator material it is recommendable to provide the plate(s) with a number of apertures 26 as is shown in Figure 11. Said apertures 26 are also desired when a synthetlc foil wetted with an adhesive is used as an insulator, but in this case they are desired for causing any gases formed during heating to flow away. Said gases occur notably when a foil is used of ' "
.
-~7~35~
a polyimide of 4--4' diaminodiphenyl ether and 1, 2, 4, 5 benzenetetracarbonic acid dianhydride which is wetted with a solution of a polyimide of the same materials, in which gases are formed during polymerisation in which the poly-amide is converted into the polyimide.
After folding the plates together they may not contact each other. For that purpose, during assembly so-called suction plates may be used the operation of which will be explained with reference to Figure 14. It consists of a stain1ess steel plate 34 of a fen cms thickness which .. has been made tension free and has the correct shape and flatness within the desired accuracy. The suction plate comprises a number o~ slots 35 which can be made to communi-cate with a vacuum line 36 via a duct. The plates secured one on top of the other are sucked on such suction plates and provided on each other at the desired distance, with . . .
the interposition of the insulator 15, and heated to a ..
temperature which is sufficiently high for the insulation material so that the adhesion is produced. ...
As shown in Figures 12 and 13 in two parts of :
sectional views through two plates 27 and 28 comprising a relief and secured together at an angle of 90, the correct distance can also be obtained by using spacing elements between said plates in the form of a sphere 29 or a rod 30, rPspectively, which spheres or rods are removed together with the strip shaped regions.
Figure 15a is a sectional view of a part of a plate having a relief pattern which consists at least at surface of aluminium. By anodizing the parts 31 of the : 3~ ridges 13 consisting of aluminium at least at the surface, said aluminium is converted at that area into an A1203 layer 31 which, as is known, is an insulator. Another plate :.
~LO 7 ~3~jZ PHN 8262 32 is secured against the anodized layers and the strip-shaped regions are removed again (Figure 15c). Said plate 32 may also be a plate having a relief pattern or may be an apertured plate. In order to ensure the screening of the electron beams from the earth's magnetic field, at least one of the plates of the colour selection means 7 preferably consists of a ferro-magnetic material, for example Fe, Co, Ni or alloys of or with said metals.
Figures 16a and b show a part of colour selection means which comprise a plate 33 having apertures 9. A plate having a relief is secured against said plate by means of an insulator 15 so that the ridges 13 become situated between the ~ .
apertures 9. By removing the strip-shaped regions 14 the .
colour selection means as shown in Figure 16a are obtained.
The operation thereof is shown in Figure 16b. The three phosphor strips associated with the aperture 9 are shown on the display screen 6 in the same manner as in Figure 5b.
; The conductive strips 17 are connected together and are at a lower potential~than the plate 33 so that the desired . 20 quadrupole lens is formed in the aperture as a result of which the electron beam is displayed as a spot 10. .
A display screen for a tube according to the in-vention can be manu~actured by means of a known exposure method in which the colour selection means are displayed on ~S a photosensitive layer on a window portion of the tube. Small variations in the distance between the conduc~ive strips of set 16 cause defects in the width of the phosphor strips. ~ .
The method according to the invention prevents such variations in that during the manufacture of the colour selection rneans the distance between the conductive strips (ridges 13) is ~.
fixed by the strip-shaped regions 14.
. In connection with the great transrnission of the .
. .
- 16 - . :
,5zl colour selection means according to the invention, the exposure method used should be suitable to display the aper-ture 9 in a conslderably narrowed manner to get the phosphor strips with the right width. An exposure method suitable for this purpose uses two or more light sources at some distance from each other, as described in German patent application 2,2~8,878 by Sony and published on April 19, 1973. Of course, a tube according to the invention is also excellently suitable for so-called electronic exposure in which the sensitive layer on the window portion is "exposed" by means of an electron beam.
It will be obvious that constructions in which more than two plates are secured together with the inter-position of an insulator also fall within the scope of the present invention. According to the method of the invention, for example, not one plate but two plates having a relief pattern may be secured against a plate having apertures 33 as shown in Figure 16a, so that a set of parallel strips is formed on two sides of the apertured plate. Very symmetrical quadrupole lenses can be obtained with such a construction.
- 17 ~
. ' '`""~
' . . .. .
.. . .
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
CLAIMS:
1. A method of manufacturing a cathode ray tube for displaying coloured pictures and comprising in an evacuated envelope means to generated a number of electron beams, a display screen comprising a large number of regions luminescing in different colours, and colour selection means comprising a large number of apertures which associate each electron beam with luminescent regions of one colour, which colour selection means comprise electrodes to form an electron lens in each aperture, characterized in that the colour selection means are manufactured from two metal plates which are secured against each other with the inter-position of insulation material so that the plates do not contact each other, at least one of the plates, prior to the plates being secured together, being provided with a relief pattern which is composed of a number of substantially parallel ridges between which a number of strip-shaped regions are present in which the plate(s) has (have) a much smaller thickness than at the area of the ridges, the material of said strip shaped regions being removed after securing the plates together.
2. A method as claimed in claim 1, characterized in that the colour selection means are manufactured from two metal plates of which one plate is provided with apertures and the other plate is provided with the said relief pattern so that the apertures become situated opposite to the said strip-shaped regions.
3. A method as claimed in claim 2, characterized in that the apertures are formed by etching, together with the removal of the material of the strip-shaped region by means of etching.
4. A method as claimed in claim 1, characterized in that the colour selection means are formed from two plates which are both provided with the said relief pattern and that the plates are secured together in such manner that the ridges enclose an angle of approximately 90° with each other.
5. A method as claimed in claims 1, characterized in that the insulation material is glass which is provided in the form of glass powder on at least one of the plates, after which it is converted into solid glass by a thermal treatment and the excessive glass, after removing the material of the said strip-shaped regions, is removed.
6. A method as claimed in claim 5, characterized in that one of the plates which is provided with a relief pattern is then covered with an insulator so that only the ridges remain uncovered, which ridges are then coated with glass powder electrophoretically, after which the insulator is removed, which glass powder is converted into solid glass by a thermal treatment, after which the plate with the covered ridges is secured against a second plate.
7. A method as claimed in claim 6, characterized in that the electrophoretic coating is carried out in an electrophoresis bath which contains an alcohol, preferably methanol, in which glass powder is suspended.
8. A method as claimed in claim 1, characterized in that a refractory synthetic foil is provided between the plates as an insulator and the excessive synthetic material and the material of the said regions are removed.
9. A method as claimed in claim 8, characterized in that the synthetic foil is wetted on at least one side with an adhesive for the synthetic material of which the foil consists prior to being provided between the plates.
10. A method as claimed in claim 8, characterized in that the synthetic foil consists of polyimide.
11. A method as claimed in claim 10, characterized in that the polyimide foil is wetted on at least one side with a solution of a polyamide before being provided be-tween the plates, after which the polyamide is converted into polyimide by heating.
12. A method as claimed in claim 11, characterized in that said polyimide is the polyimide of 4-4' diamino-diphenyl ether and 1-2-4-5 benzenetetracabonic acid dianydride.
13. A method as claimed in claim 5 characterized in that the plates are kept at the desired distance by spacing elements.
14. A method as claimed in claim 13, characterized in that the spacing elements are spherical.
15. A method as claimed in claim 1, characterized in that at least one of the plates consists of aluminium on at least one surface, which surface is at least partly anodized as a result of which the insulation material in the form of aluminium oxide (Al2O3) is formed.
16. A method as claimed in claim 1 characterized in that the material of the strip-shaped regions is not removed entirely so that edges are formed at the ridges.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7600417A NL7600417A (en) | 1976-01-16 | 1976-01-16 | METHOD OF MANUFACTURING A CATHODE RAY TUBE FOR DISPLAYING COLORED IMAGES. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1074852A true CA1074852A (en) | 1980-04-01 |
Family
ID=19825452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA269,551A Expired CA1074852A (en) | 1976-01-16 | 1977-01-12 | Method of manufacturing a post-deflection focusing colour selection electrode |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5289066A (en) |
| BE (1) | BE850408A (en) |
| CA (1) | CA1074852A (en) |
| DE (1) | DE2700139A1 (en) |
| ES (1) | ES455014A1 (en) |
| FR (1) | FR2338567A1 (en) |
| GB (1) | GB1509701A (en) |
| IT (1) | IT1077853B (en) |
| NL (1) | NL7600417A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL7711773A (en) * | 1977-10-27 | 1979-05-02 | Philips Nv | COLOR IMAGE TUBE AND METHOD FOR THE MANUFACTURE OF SUCH COLOR IMAGE TUBE. |
| US4350922A (en) * | 1980-06-20 | 1982-09-21 | Rca Corporation | Multicolor cathode-ray tube with quadrupolar focusing color-selection structure |
| US4311944A (en) * | 1980-06-27 | 1982-01-19 | Rca Corporation | CRT With dipolar deflection and quadrupolar-focusing color-selection structure |
| US4464601A (en) * | 1982-08-11 | 1984-08-07 | Rca Corporation | CRT with quadrupolar-focusing color-selection structure |
| GB2326018B (en) * | 1997-06-07 | 2002-01-09 | Ibm | Grid electrodes for a display device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL7117919A (en) * | 1971-12-28 | 1973-07-02 | ||
| US3923566A (en) * | 1972-06-21 | 1975-12-02 | Rca Corp | Method of fabricating an apertured mask for a cathode-ray tube |
| NL167798C (en) * | 1974-07-17 | 1982-01-18 | Philips Nv | ELECTRON BEAM FOR DISPLAYING COLORED IMAGES. |
-
1976
- 1976-01-16 NL NL7600417A patent/NL7600417A/en not_active Application Discontinuation
-
1977
- 1977-01-04 DE DE19772700139 patent/DE2700139A1/en not_active Withdrawn
- 1977-01-12 CA CA269,551A patent/CA1074852A/en not_active Expired
- 1977-01-13 IT IT1927677A patent/IT1077853B/en active
- 1977-01-13 GB GB130377A patent/GB1509701A/en not_active Expired
- 1977-01-14 FR FR7700981A patent/FR2338567A1/en active Granted
- 1977-01-14 BE BE174105A patent/BE850408A/en unknown
- 1977-01-14 ES ES455014A patent/ES455014A1/en not_active Expired
- 1977-01-17 JP JP386777A patent/JPS5289066A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2338567A1 (en) | 1977-08-12 |
| BE850408A (en) | 1977-07-14 |
| DE2700139A1 (en) | 1977-07-21 |
| JPS5289066A (en) | 1977-07-26 |
| JPS5745013B2 (en) | 1982-09-25 |
| ES455014A1 (en) | 1977-12-16 |
| NL7600417A (en) | 1977-07-19 |
| GB1509701A (en) | 1978-05-04 |
| IT1077853B (en) | 1985-05-04 |
| FR2338567B1 (en) | 1981-08-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |