DE1462974A1 - Process for the production of color screens for cathode ray tubes - Google Patents

Description

SONY CORPORATION (SONY KABUSHIKIKAISHA), 351, Kitashinagawa-6, Shinagawa-ku, Tokyo, Japan

Process for the production of color screens for cathode ray tubes »

The invention relates to a method for producing color screens for cathode ray tubes used in color television receivers and in particular the manufacture of strip-shaped screen surfaces, such as those in cathode ray tubes according to the after-deflection-focusing principle (postdeflection-foousing type).

Many color cathode ray tubes have been proposed for this purpose, such as a shadow mask tube, a shadow mask tube with the after-the-distraction-focusinga-principle, a beam-indexing tube, a drill according to the naoh-der-distraction-focussing-principle, the color-so-hold-grids owns. In all such color cathode ray tubes the electron beams emitted by the electron gun

are emitted and by a signal that a predetermined Corresponds to chrominance signal, in which the density is modulated, exactly hit the previously determined phosphor stripes emit a color according to the chrominance signal. To do this, a phosphor dot screen is usually used for the shadow mask tube by an optical printing process in which a shadow mask is used as an optical mask is used. That is, the shadow mask is attached in the same relative position as the mask and the screen in the finished tube, and a light source is placed in the deflection center of the electron beams, whereupon the inner surface of the face plate, which is coated with a photosensitive material, through the mask Light rays is exposed and subjected to a development process thereon. This sequence of steps is for each of the colors represented on the screen is carried out to produce the multi-colored phosphor screen. The optical printing process however, it cannot be used for the other types of color cathode ray tubes which is based on the fact that the real path of the electron beams from their center of deflection until the screen is not straight. In order to overcome the difficulty encountered in this process, the so-called Electron beam printing method proposed in which ■ to the electron beam on a screen, which with an organic photosensitive material is coated, under substantially the same operating conditions as in the finished one Cathode ray tube, and in which phosphorus deposits, each of which is a predetermined color

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emitted, are formed at predetermined locations on the screen.

According to this method, since the electron beam printing is carried out in a tube which is evacuated to the pressure, which is used in the actual operation of the television receiver, the so-called "fog" under the influence generated by dust or the like of the tube in the photosensitive layer, and thus electron beam printing can be permanent can be achieved. Furthermore, one must of course evacuate at least two or more times and an electron beam pressure because a multicolor phosphor screen is produced. Accordingly, it requires conventional Procedure inevitably many steps during the manufacturing process, and consequently is not suitable for mass production.

Accordingly, the present invention aims to provide a method of manufacturing color phosphor screens using a photograph of a screen face made by the electron beam printing process in which an optical mask is placed in front of the screen is made from this photograph and in which a multi-color phosphor screen is formed using the optical mask , thereby obtaining a multi-color phosphor screen with a single evacuation.

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The invention further aims to provide a method of production of color phosphor companies to indicate the advantages of both the electron beam printing process and the optical printing process Printing process used.

In the · objects, features, and advantages of this invention from the following description in connection with the accompanying drawings, in which ι

Fig. 1 shows a son through a "Chromatron" cathode ray tube to provide an example of the process for the Manufacture of a color shade according to the present invention To explain the invention

Figure 2 is an enlarged fragmentary sectional view of the screen of the tube showing the relative placement of the color phosphor strips and grids;

Flg. 3 is an eohematic cut through the frontal surface a cathode ray tube which is used for the manufacture of Ines Farb-Fhoephor-Sohirmes according to the present invention

FIGS. 4 to 6 thus explain, using an example, a sequence of postures according to the present invention}

7 shows an example in an eoheaaUsohtn representation • Ines photographic image taken during the

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Manufacturing processes of the method according to this invention;

Pig. Fig. 8 also shows an example of an optional printing process according to the invention;

Figures 9 and 10 show steps in the second half of the manufacturing method according to the invention; and

FIGS. 11 and 12 are similar positions for explaining the invention.

With reference to the drawings, the present invention will be described on the basis of the production of a multicolor (multicolor) phosphor screen for the "Chromatron" cathode ray tube will.

Like from Pig. 1 can be clearly seen, the "Chromatron" color cathode ray tube, which is generally designated by the reference numeral 1, contains a slectron cannon device 3 which is mounted in a shark part 2 of the cathode ray tube 1 Deflection coil 5, which is attached to the outside of the conical cable 4 of the tube 1, a multicolor phosphor screen 7 which is sprayed onto the inner surface of the end face 6 of the tube 1, and a naoh-Ablenkungs-Jooueierunge-öitter device 8 The combination of the deflection coil 5 and the carbophosphorus tube 7 is attached. The electron gun assembly 3 is usually designed to have one

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Electron beam is generated, and ea are signals corresponding to the colors Bot, Green and Blue, successively on the device 3 is applied, and accordingly a received electron beam modulated in the diohte. In Pig. 2 let us show an example of the color phosphor screens 7, the of red, green and blue phosphor strips 7B, 7G and 7B which are arranged in a repeating sequence of red-green-red-blue «The grid device 8 consists of two Groups of grid elements 8a and 8b which are placed opposite the blue and green phosphor strelves 7B and 7G, each group of elements being interconnected. A switching signal is generated between the grid elements 8a and 8b in accordance with the color signal applied to the Electron gun device 3 is given. The switching signal is, for example, a square wave voltage or a sine wave voltage with a carrier frequency of 3.58 MHz. With such an arrangement, a red color is generated by the impingement of the electrons of a beam on the red phosphor strips 7H when the grid elements 8a and 6b are on the same potential. When the grid elements 8a are positive with respect to the grid elements 8b, the electrons hit of the beam on the green phosphor strips 8G. Under the opposite condition, if dl · grid elements 8a are negative and the grid elements 8b are positive, the electrons of the beam impinge on the blue phosphor strips 7B. The grating device 8 mentioned above is usually in one Bohemia collected and detachably attached exactly dsm phosphor screen 7 opposite. In this embodiment it is from

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primary importance, the grid torque 8 as accurate as possible to attach to the end face 6 in bending.

In the following, the production of such a phosphor screen for the ^M Ohromatron ^N larb cathode ray tubes will be described. A face plate panel 6 is produced as shown in FIG. In the first method, the entire inner surface of the end face disk 6 is first coated with a photosensitive material layer 9, which is hardened by the irradiation with electron beams. Then a grating device 6, held in a frame, similar to the one mentioned above, is attached opposite the inner surface of the end face disk 6 exactly in the position which it assumes in the finished cathode ray tube.

The front surface is then mounted on the conical cable 13 of a removable cathode ray tube 10 as an electron beam and torrlohtung, see FIG. 4 gaseigt, aufeaatst. The detachable cathode ray tube 10 is under construction essentially exactly ao «la the finished cathode ray tube, with the exception that it occupies an "Auapump line 12". Correspondingly, the tube 10 is provided with a gate valve, an electron gun torch 14, a deflection coil 11 and the pump line 12. When raising the frontal surface, 6 The agitator 10 is an adjacent surface 6a of the frontal surface area 6 with the area 1Ya of the Konlsohen Telia · 13 der & 0hre 10 connected. Then the "Ird 41" tube evacuated through the Auapumpleltung 12

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a sealant such as grease on the adjacent surfaces 6a and 13a related, so that an airtight connection between the face disk 6 and the tube 10 is established * The cathode ray tube 10 is kept under such a pressure, e.g., 5 × 10 "" * mmHg, as it is in actual operation of the television receiver is being used. Under such conditions, an accelerating voltage and a deflecting voltage are applied the electron gun device 14 or the deflection coil 11. In this case, however, it is not necessary to rather, the electron gun device 14 will apply voltages according to the red, green and blue color signals the electron gun device 14 is designed so that during the whole time an electron beam of a certain Density is generated. Furthermore, the grid device 8 eo is designed so that the voltages are optionally applied to it - that can be used in the finished tube.

With such an arrangement, such a potential is given to the grid device 8 that the grid elements 8a positive and the grid elements 8b become negative, so that an electron beam therefrom. 17 on the coated inner surface the face disk 6 strikes at such locations which finally should be green phosphor strips 7G, whereby green latent image areas are created.

A second electron beam printing is then carried out, and such a potential is applied to the grid device 8 becomes that the elements 8a negative and the elements 8b poeiti-y

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are to the electron beam 17 in a similar manner to sol- • Chen points to hit the coated inner surface of the face disk 6, where blue phosphorus stripes 7B are intended to be in the finished tube, creating blue latent image areas.

Thereafter, air is let into the tube 10 through the pump-out line 12, and the face disk 6 with the grating device 8 is removed from the conical part 13 of the drill 10. The grating device 8 is also removed from the face disk 6. The inner surface of the face plate 6 is then subjected to a development process which consists in washing the entire inner surface of the face plate 6 with water, for example, in order to optionally wash off the photosensitive material surface 9 from those areas which have not been exposed to the electron beam Areas which are to form the red phosphorus strips JB1 in the finished cathode ray tube 1, as shown in FIG. 1. As shown in Fig. 5,
by this selective removal of the photosensitive Haterialschioht 9 an end face disk 6 'is formed on the
the photo-sensitive material strips 9 ¹ are lying, which have become hard in the places which are supposed to be taken up by the blue and green phosphor strips 7B and 7 &.

After a succession of such trials, practice the front surface 6 * becomes a mask for use with the optically designed printing process », as described in the following

A light source 15 is first placed in the flrtfffHyfyJnrJfcartfgB: deflection center or center point t- opposite the inner surface of the face plate 6 *, while a photographic plate 16 is set up opposite the outer surface of the face plate 6 *. As can be clearly seen from Hg. 11, the deflection center t- is the point at which the straight line 27 intersects the axis XX of the end face disk 6 *, the line 27 being the point P _Q between the grid elements through which the electron beam 17, which is deflected by the deflection coil 11, passes through, connects to the point P ₁ on the inner surface of the face disk 6 ¹ on which the electron beam 17 impinges after passing through the

fine -.- Pocusiersspannung ^ has been deflected, which is applied between the grid device 8 and the conductive layer of the face plate 6 * or its metal backing layer. The photosensitive material strips 9 'are, if necessary, previously made opaque with a suitable paint. Under these conditions, the photographic plate 16 is exposed to light from the light source 15 through the face disk 6 * on which the photosensitive material strips 9 ^{1 are} deposited, whereby latent image areas are formed on the photographic plate 16 in accordance with the stripe pattern formed by the stripes 9 ¹ on the inner surface of the face disk 6 '. The photographic plate 16 is then developed to obtain a negative plate 18.

The next step is that a mask is made for use in the optical printing process

. the negative plate 18 is used. That is, the negative plate 18 and a photographic plate 22 are arranged opposite each other with a line 19 therebetween, as shown in FIG is shown, and the photographic plate 22 is illuminated with light from the outside of the negative plate 18 as it is through the arrows indicated iet, exposed, causing on the plate 22 the photographic image of the negative plate 18 is imaged. The photographic plate 22 is then developed to be a optical mask 24 mask 24 is used to form red phosphor stripes, as will be described later, and this mask 24 is at locations the blue and green phosphor stripes B and 6 correspond to which are to be deposited on the screen of the finished cathode ray tube, opaque, but transparent in places that ultimately correspond to red phosphor stripes B. lying on the screen, such as it is shown in FIG. Reference numeral 25 denotes a transparent carrier film of the mask 24.

The mask 24 then faces the inner surface of the face disk 6 * and the light source 15 is in

apparent
brought the *** "*" deflection center t ₁ , which is at a distance L ₁ from the face disk 6 *, as shown in Hg. β. Under such conditions, the mask 24 is moved along the axis XX of the end face plate _{6 'in order to establish such a distance L 2} between the end face plate 6 * and the mask 24 that the stripe pattern of the mask 24 exactly matches that of the photosensitive material strips 9' coincides, which was previously on the surface of the forehead

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flat washer 6 'have been formed.

. -or . Phosphor slurry Then a liquid phosphor brelY consisting of a red phosphorus and a photosensitive lacquer is spread over the entire inner surface of another end face disk 6 ″, as shown in Fig. 9A by 20E, on which the phosphorus Stripes are to be formed. The application of this red phosphorus pulp layer 2OR can be carried out by any conventional method. The face disk 6 '″ is brought into exactly the same position in relation to the mask 24 and the light source 15 as the face disk 6'. The photosensitive varnish can be a mixture composed of polyvinyl alcohol, ammonium dichromate, water glass, etc.

The coated inner surface of the face washer 6 ″ is then exposed to light through the mask 24 from the light source placed behind the mask 24 as it is indicated by the arrows. The photosensitive material is usually extremely sensitive to ultraviolet light, so that a xenon lamp, a mercury arc lamp or the like. is used as light source 15 in this case. As can be seen from Fig. 9B, only a few become during this exposure Parts of the red phosphorus pulp layer 2OR exposed by the light, since the other parts of the layer 2OR remain be shielded by the opaque parts of the mask 24. The red Phoephormrei hardens in the areas with Lioht have been exposed. In the next stage, the -

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Excess phosphor layer, which has not been exposed to light, washed off by rinsing with water, while the hardened red phosphorus stripes 2OR are left lying next to each other at predetermined intervals, like it is shown in Fig. 9C.

The red phosphor strips 2OR are then colored so that they become opaque, and a material 21, such as, for example, wax or enamel or laok (enamel), which does not let light through and can easily be removed by a solvent, is applied over the another blank area is applied between the red phosphor stripes 2OR, as in Pig. 1ΟΒ shown let · The application can be carried out using any desired method such as spraying, as the red phosphor strips 2OR are a considerable distance from each other. Then, a green liquid phosphor slurry applied to the entire inner surface of the Stirnfläohenschelbe 6 "as indicated in Pig. 100 by the reference numeral 20G. The thus-coated surface is beliohtet with Lioht of the Rüokseite the Stirnfläohensoheibe 6 ^M ago, then is the coated surface is rinsed with water to optionally remove those areas which have not been exposed to the light, and then the material 21 previously applied to the blank areas between the red phosphor strips 20B is rinsed with Toluene or acetone removed, and as a result, green phosphor stripes 2OG are obtained, which are alternately sprayed between the red phosphor stripes 2OR, as shown in Fig. 10B

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Formation of the green phosphor stripes 2OG, the red and green phosphor stripes 2OR and 2OG, which are applied to the inner surface of the face disk 6 ″, are colored or painted to make them opaque, and the entire surface is given a blue - phosphor slurry coated, as shown in Figure 10E by the reference number 2OB, and then the face plate 6 ¹ · forth is exposed to light from the back.. During the exposure, the parts of the blue phosphor pulp that have been applied to the empty areas between the red phosphor strips, while the remaining parts of the blue phosphor pulp, which are over the red and green phosphor strips 20R and 2OG, are shielded by these strips with respect to the effect of the exposure. As in the previous process, the inner surface of the face disk 6 ″ is then rinsed with water, leaving behind blue phosphor stripes 20B, as shown in Pig and blue phosphor stripes that follow one another ^ are arranged in the order red-green-red-blue-red-green etc.

In the foregoing, every other empty space between the red phosphor stripes 2OR against the light through lichtundurohlässiges Material such as wax or the like. Shielded, whether the blue or green phosphor strips according to the one in the FIGS. 91 to 90 to generate the process step shown. In such a case, however, only certain parts can be used

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the green vin ^ sphorbrei coating is exposed to light, by the relative position of the mask 24 in relation to the face washer 6 "is changed without using the wax.

In the following, the refraction of light through the glass of the front ^{surface pane 6 1} during the production of the negative plate 18 will be discussed. Where the screen surface of the end face disk 6 * is flat, essentially the same influence takes place through the refraction of light over the entire surface, so that the refraction does not play a role. However, since the screen surface of the face plate 6 ^{1 is} curved, the refraction of light is of course different over the screen surface. In order to avoid this, the outer surface of the face disk 6 * is formed, for example by foiling or grinding, in such a way that it represents a non-spherical lens. Mg. 12 shows a schematic representation to explain the principle of the correction.

The inner surface of the face disk 6 'is designated by 30. Hit 31 and 31 * are the outer surfaces of the face washer 6 * denotes after and before the correction. A beam of light 32 which the inner surface 30 at an angle of incidence β meets, is broken on the inner surface 30 so that it passes through the face washer 6 'at an angle of β' passes through. In this way, the light beam 32 hits the outer surface 31 at an angle of incidence of (ß-Λ) and it is then shown with an angle of refraction of (* -Λ)

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broken so that it falls on the photographic plate 16 in the Point 33 is projected.

If the angle \ forms an acute angle between the outer surfaces 31 and 31 ', where η ^{indicates the refractive index of the face disk 6 1} , the following equation applies *

3 _ sinfr--

sin

fr-A) fa'-λ)

From these equations, the following expression can be derived:

tan A =

- cosCX

The angle A can be obtained from the angles β and c <. In this case, the point 33 lies on the photographic plate 16 on which the refracted light beam from the outer surface 31 of the face plate 6 ¹ hits ^ on the extension line of the incident light beam 32. Accordingly, the outer surface of the face plate 6 * is corrected so that it corresponds to the angle A is sufficient and consequently the influence of the refraction of the face washer 6 * can be eliminated. The end face disk 6 'is preferably ground by electron beam printing, since the end face disk 6 ¹ becomes mechanically more fragile as a result of the grinding. Furthermore, the influence of the refraction of the face ^{washer 6 1 can} be switched off by the fact that the in Pig. The process shown in FIG. 5 is carried out in a container which is filled with a liquid of the same refractive index as that of the glass of the end face disk 6 ^1.

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As described above, the tube according to the present invention only needs once for the Electron beam printing is used in making the mask 24 to be evacuated, and the color phosphor screen is through optical processes without the need for further evacuation, so that the method according to the present invention requires fewer manufacturing processes than the traditional method in which electron beam printing is used for all processes. The method according to the invention is therefore suitable for the mass production of paraphosphorus cores for cathode ray tubes.

Furthermore, the present invention relates to manufacturing by color phosphorus companies for wide-angle deflection and bipotential cathode ray tubes can be used

Se is believed to be possible, an optical mask as a result, see below that produce a photographic plate with light from the The front side of the face disk 6 * is exposed in the process shown in FIG. 5 with such an arrangement, that a lens is placed in the place of the light source 15 and the photographic plate bo is exposed through the lens, that the pattern of the photosensitive layer 9 'is obtained In a solo case, however, since the solid angle is in the • A visible center of deflection tj, 4 opposite the screen is, however large, required in the Phoephor screen of the wide-angle deflection or bipotential cathode-ray tubes, a wide-angle line, and it becomes practiaoh difficult because of the

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Deterioration of the lens to get a mask that one has a predetermined stripe pattern. According to this invention, however, no lens is used in the exposure of the photographic Plate 16 related to light and the degree of resolution of the stripe pattern of the face disk 6 ·, which is on of the mask 24 and the negative plate 18 is obtained, is small compared to the pail in which a lens is used, βod that a flawless lens with a long focal length according to this invention can be used. Consequently, the color phosphor screen can for wide angle deflection or bipotential cathode ray tubes can be precisely manufactured.

In the foregoing, the color screen is produced before the grating device 8, which is attached to the end face disk 6 ", is introduced, but it is expedient that the grating device 8 is introduced from here and then the color phosphor screen in accordance with In such a case, the face disk 6 ^fl on which the grating device 8 is attached, the mask 24 and the light source 15 are arranged in the same relative positions to one another as shown in FIG. Slurry layer 20E, which is applied to the inner surface of the face disk 6 ¹ ', is fUwefe exposed through the mask 24. Thereafter, the mask 24 is rotated about the axis XX until a spurious pattern or a moiré pattern is shown by of the interferons caused by the mismatch between the stripe patterns of the mask 24 and the grating device 8.

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arises, becomes a predetermined symmetrical pattern. After this setting, the grid device becomes 8 removed from the face disk 6 * 'and the red phosphorus pulp layer 2OE is exposed through the mask 24 and then the same processes as described above are carried out, executed. After the production of the color screen, the grating device 8 is placed on the face disk 6 · 'in

the previously determined location attached to this, whereby the Grid device 8 can be held on the color screen in the predetermined position.

Although the present invention relates to the manufacture of the multicolor phosphor screen for the "Chromatron" color cathode ray tube has been described, the invention can also be applied to color phosphor screens for post-deflection focusing -, Shadow mask and other types of color cathode ray tubes be used.

It is obvious that many modifications and changes can be made without falling outside the scope of the present invention Invention to leave.

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Claims (5)

U62974 claims: 1.) j method for forming an optical mask for producing a color screen for a cathode ray tube, characterized in that such areas of a photosensitive Coating on the concave inner surface of an end face disk by an electron beam which are sensitive to the impact of this beam through row grids are scanned, which are attached near this surface; that a visible record of the impact of the electron beam is developed; that this visible recording of this face disk with light from the concave side of the End face disk is exposed to the pattern corresponding to the visible recording on a photographic Map the plate that is placed on the convex side of the face disk at a distance therefrom It means that this photographic plate is developed to form a photographic pattern and that it is an optical one Mask is formed which is derived from this photographic pattern. 2.) A method for forming an optical mask for producing a Parbechirmee a cathode ray tube according to claim 1, characterized in that "that the light source · in the apparent Deflection center of the cathode ray tube is set up. 809812/0898 3.) Method of forming an optical mask for producing a color screen of a cathode ray tube according to Claims 1 and 2, characterized in that the convex side of the face washer is ground in such a way that that the point on the photographic plate through which the refracted light beam from the convex side of the End face disk passes through, lies on the extension line of the incident light beam. 4.) Method of forming an optical mask for producing a color screen of a cathode ray tube according to Claim 3, characterized in that the grinding of the face disk after scanning by the electron beam is performed. 5.) Process for the production of a color screen for a cathode ray tube, characterized in that an original face washer on which one is visible Recording of the point of impact of the electron beam is attached, is provided; that this visible record is exposed to light that is incident from the concave side of the end face disk that this Exposure pattern corresponding to the visible record is imaged on a photographic plate which is placed on the convex side of the face washer is set up; that this photographic plate is developed to be a to form a photographic pattern} that an optical mask is formed from this photographic pattern, that a 809812/0898 -22- H62974 Cathode ray tube face washer, which has substantially the same shape as the original face washer) is provided; that a phosphor slurry is applied to the inner surface of the end face disk , and that this end face disk is exposed to light which is radiated from the concave side of the end face side through the optical mask. 809812/0898