DE2030072A1 - Method for producing a temporary color mask for a color picture tube - Google Patents

Description

RCA Corporation, New York, N. ¥ " _s V" St * A.

Method for making a temporary color mask for a

Color picture tube Λ

The invention relates to a method for producing a provisional color mask for a color picture tube ^, wherein the provisional color mask is made from a thin piece of sheet metal with; a * pattern of openings or holes and with a layer of material attached to one surface with preliminary holes - which coincide with the holes in the sheet metal piece *, but are smaller than the corresponding holes for the purpose of printing the fluorescent dots on the tubular visor in the sheet metal piece ;, consists.

A known type of color picture tube has a © riser ■ color mask. (Shadow mask or perforated. Electrode) for directed att.sbl0sad.en of the fluorescent screen. During the manufacture and operation of the tube. The screen consists of several, usually three, "similar patterns or grids of fluorescent or color elements in the form of lines or points on the inner surface of the tube faceplate Color luminesces. The _{Farbelement-%} raster are joined into one another, daft adjacent elements in each group, each with a color element from each grid "form in"

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v © a &> esi Le ^ atsMsstatfiPas-iSGJm "ni-fc Eo-fe- _s Griisa- and Blau ssinadl dia ο Gi? ü £ ppQEB lsi © ε» ©! © im or Tripelra vom

Ϊ3 der FaspfosasIsQ UQ <sht, see each HasIceialoeSii with each. a aiadaiPQE S ¹ S = IpQl v © tm Lemelires & oiriJGlenGEii-feesi,) s @ that by eiaselnea Liem-QS ⁵ SaiEaflM © k & FG fceffi (I © £ ^eira:?> gleküjjrOjaosastrahl each inHHei m.uf θ-Ib FapfeGleoeK-fe dsa Tripolsj © deir des ⁰ Grsappe -fc ^ iff-fc, while the βεί'ίΪΘίΡΘΒ FairteeiQiQea-fee deir SSE ¹ FEiSpG etoaE ° <2ta the Faybiaaske gedie Elefc & FoaG & steaEiiiQia. © ieEs®Eifeii £, i? N ie-E e ± Be © n'fesps ^ eöSüensdl © Fofeh ^ boxßjpilQisweise the Voss round holes parallel Lassglä-eEiiQifEii (SeIÄit.sesa) feabesii) which form the

The Leia. (S! A'i; s'öGicfGlQneEiit; e im Any Gs ^ appe gisad so

that the ElelcfezOSieastiSOSal at the ÄbleEBETOEig iüfoeK ⁰ the color mask in each case a SlGEiGsaiä eise glQickQBa Fa ^ feifas-aers 1 & 2 »± £ ffc“ Asadere ElektroneBstralileiu 'dK ^ eSase-teaei ^ dK ^ eSase-teae © In the Slene trianaiske s eja ^ sprechesid aiadieipeir 'Fax ° bir £ iber "meet _o

Morma3LQs ° wise iSQ ^ aon die eiraselüaea LewcHi'fcs'fco'ff- or color raster diiE'oa pin © 'öogjpapSiiis © feei3 BjfiaskQEu s.wE the froatplaiiibe of the tube on / brought β Bies cut; alia des ³ Ifei-se ^ that the Fromibplatte with; a 'layer of eiiaeE GeoilGefe des fosifes ^ eiffeldern Leuchibstoffs and a lichibeiHpfiBdüicheia Ä ^- fessGEam-ibsE3l - &'& eiLs (PSaoibolack) beschich-fce "fc is", the mask is placed in the deip Maine the ³ Fjpo fe., which she is the feK = - & igeEa Hötee eiaHairaa-fe _o The Phoibolack-Leuchtstioffschieki; tjis? d dm ^ efe the mask is exposed _s whereby the light the Maskeiilöc & ei ³ iia S-fcraM-eEagSEageia duupclhiseiczibea, die fcrai eiczibea ia Operation of the ³ Eölaire eia-fcsprecfeesao The procedure is used for the asaderesa F & rhwa & bQiP ^ iisdeFhol-fcp where the light> in accordance with asadeipeEs EisIirifoiKtgess duirch the mask ge rich-teib wipd _o Eia Yerfatoeia is this = · Ae ^1- O -Fatenubschrift-fc 3 406 068

When the tubes © bea bescferiebemesi Art · is the width of Leucivbstof £ eleaeatsj, whether eisa Lisaiesieleaejat or © iss Punktele-. ment j usually larger than that of the punishment! stain ^ da der. beam

^BAD ORIQJNAl

be compressed by focusing fields between mask and screen can. Likewise, the one that forms the phosphor element on the screen de or printing light spot larger than the mask hole through which the Lichijhin passes. The size of the phosphor element can also be controlled as it is directly related to the Exposure time is.

In order to increase the light yield and the efficiency of the screen, it is desirable that each individual fluorescent element is fully covered by the electron beam concerned. That is, the width of the beam spot should be as large as or greater than the width of each phosphor element. To achieve this, the mask holes should be smaller when screen printing than they are when the tube is in operation. Is a known method (USA patent "* Document 2 o6l 314) is dai the mask before application of the perforation coated with a photoresist which has the same I ochauster or screens, as is desired for the _t finished mask . The coated mask is subjected to an etching treatment, the metal of the mask being etched away through the perforated photoresist layer. By means of controlled etching, holes penetrating the mask are created which are larger than the holes in the photoleak layer. This "provisional" or preprocessing ipe mask with the smaller holes in the photolecum layer is used for screen printing. Then, the photoresist layer removed and the g "permanent" or final mask used with the larger holes for the finished tube. This mask produces beam spots whose width is larger than that of the corresponding fluorescent elements.

A disadvantage of this known method is that photoresists, as they are normally used, during the Mask and shield manufacture worn or damaged « Masks with photoresist layers cannot be punched without wear or damage to the photoresist, and also not before Stamping will glow when a durable metal such as cold rolled steel is used. The photoresist also has to be added by adding voa opaque material to the normally transparent lacquer

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be made casual, which increases the cost of making the screen raise.

The above-mentioned disadvantages are eliminated in the production of a provisional color mask according to the invention in that one surface of a piece of sheet metal has a layer of metal with a grid of preliminary holes "coated" the other surface of the piece of sheet metal with an etch reserve film with holes coincide with the provisional holes in the metal layer and are essentially the same size as this provisional holes have _{coated 5} through the removal of the holes (the holes in the metal layer and parts of the sheet metal exposed in the etch reserve layer) in this Lö fe®s © * ₉ which layer deekesa and dea preliminary holes in the metal gröltet * as they are formed and ₉ schlxeilich u r ^ AFCS eseiPvagefilia- v © s of the other Ober.-fläch® of the sheet metal piece ejatfermt

In the 2eiclinuiig aeigsas

Fijgui i the 'fceilweise isa
a color picture tube with eisa @ a Müüteff ¹ Verweswämssg eiaer provisori- "see mask entepreeliend eiaer AusfülarisaEigsforsa the fulfillment of the image claiiPiai

Figure 2 to 5 sub-sections of the tube ia mach Fi ^ -1 air hole or color mask © it VeraEaschaialiefeuing used verscSaäedener process steps in the Eerst & Xlung the preliminary mask $

FIG. 6 is a perspective partial representation of a color picture tube screen. .'v '.'- ^ ing with, the vo ^ Xfimirigeift mask according to Figure- 5 J and

FIG. 7 is a diagram of the section of the light used for the manufacture of a preliminary mask according to another embodiment of the invention. Arrangement*

. The cathode ray tube or color picture tube IO shown in FIG. 1 has a glass bulb 12 consisting of a funnel or cone part 14 and a cap 16 with a transparent front plate 18. On the inner surface 22 of the transparent front panel 18 are ″,

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ORIGINAL

203OO72

a plurality of fluorescent or color elements 20, consisting of groups of fluorescent materials which emit light of different colors when an electron beam 2-1 strikes them, attached. The color elements 20 are exaggerated in size and each shown as point-shaped. Instead, the color elements can also be strip _s the tips are arranged in a pattern or grid of alternating strips of the "different phosphors, so that a Linxenrasterschirm..ergibt. The. Color picture tube 10 also contains a number of beam systems as well as either electrostatic or electromagnetic deflection. and directions of convergence (not shown) « g

A color mask or perforated electrode 30 _5, which is held by means of a suitable frame 32, is arranged at a uniform distance from the screen 24. The Farbsaaske 30 consists 34 of a certain size from a piece of sheet or strip of conductive material .and ΙμΛ VloL a number of "permanent" holes or perforations.

While the holes 34 shown in Figure 1 substantially have a cylindrical shape, you can also use holes of other shapes. Instead, the coloring mask can also use the above-mentioned "grid structure ". The holes 34 are corresponding in their size to the position -Color agents 20 of the screen 24 adapted so that the electron beam 21 passing through on the screen 24 "* generates a beam spot which in its width is at least substantially equal to or preferably greater than the width of the individual Color elements 20 on which the electron beam impinges, is. -. "'-' ...

The beam spot width is preferably equal to or greater than the width of the individual color elements, but not so large that the electron beam also hits neighboring color elements that it should not capture, overlaps. To do this, you need the holes 34 of the coloring mask 30 be considerably larger in width than that Width of the corresponding individual color elements, regardless of whether

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Ray fleck klsisaes ³ or large ³ lsi dei ³ width is as eira correspondpecheiad.es F

la Be'fcpieb der- FaipfobildiPoIii ^ e SO t-jes ^ dtes (Μ, ο Elekts * © saenstrahl 21 so directed through the Löelier 34 ^ aa, §> they hit the Fsrbelesiäejnite 20 on © Ba eisi SioFallnlfleck gFößei? er Bs WiPd generated ° age ₅ in the wesesvi; l: i © lhiesa the gesaefee Bjrei-ise eisaes einselsaea Far hast run at ements überdeelrfe ₉ dl FapfebüdliPßEas © © © © S IIaE © yJhöJite Bildhelligkeit- now it eiaesii IaSiirfcoEa K?

According to, eiaep A ^ iEfiiliirpiaiagsfoirO des ⁵ S ^ firadlaassg Wx ^ d ₅ üie ia Figure 2, shown, eiae vcDiflämKige © des * ps? © x ⁷ £ s © Pis © Sa-3 Mask diaFch phoibogpapliisches Aufd ^ uiekea olnos Hwa-fceifs or Rasters iro & elements 40 made ο Sieses MniB ^- & ep ea-fcspE ³ ! © !!!, ^ den Loctnsaiuis-fcejrs that in a die es-ägül'feigG © de :? pe ^ iaaiaea-ibe Fajfbsaaske bildeadea Met all- oder BXeehstüGh 44 ajasufe3? isagea is "fc _o Bie Eleaes ^ te 40 x-jerden aus lieirtempfiadlieheo Ätssctotz- odes = Fho ^ slaeknaterial gebildeibj, the su tieraiäQBadesa Metallätslösung uasilösli ^ fe is ο Beispiol © sslcSaeJ? Mate ^ ialäeB siad Stsscli \ ui ^- fcglacke from with. A53ja © Ki.ian = afes ³ Kalitmiabiclä p

all: »?! i © l odes = from FisefeleiEi imsw ^ff ₀ Bie Bl ^ efeisilbeiPlage 44 is ei® flat Bleefestüsk aas eiiaea effS '& Q® Ke-fcall x-Jäe S-fcahl ^ Sisem _s K fer ₃ Älaaiiaiias odes ⁵ KupfQjp -ETiekQllQgjLGffiaia ^ o to the 01bes ° flähe des Elschstiäeks 44 wl & u Q ± n F

_O etch protection "odes ^ Fjhio-feelaekaa-fce ^ ialj, which is in late d®sa ³ se the MetallätsEnittelia insoluble printed plaotogjpapifexsch ₃ Dei ¹ Filüi 48 has Perforatioaeim © dei? LSsEies ¹ SOjj the see ± m essential HiiiJ dea esatspEOeSasiadeEa PIa © 4 © la "ski3leaea * feea 40 de © kea miad at least as birsit as this one

■ As in Figui? 3 ^, is then in the generally exposed area of the oven surface 42 <? of ³ saicht sait dea Photolackeleaeatea 40 is covered ^ j else iScsBaichifc 52 galvaaisiert of second metal asigebrach-fc _o Bie ScfeicEa-fc 52 Isasäsa example Odey st3? oi9l @ s on plated Wee ° dea _o Baaii'ib. isa des ¹ * metal layer 52 sharply defined Löctoey Eaiifc aesser sharp esa are obtained _s this layer is applied in the Foria eises Filsaes; which is considerably © ädrameE ⁰ than the sheet metal piece 44ο preference

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wisely, the thickness of the metal layer 52 is less than approximately 1/5 that of sheet 44. When sheet 44 is about 0.15 ram (O, OO6 Inch) thick, a thickness of about 0.01 now (0.0004 inch) is appropriate for the metal layer

The metal layer 52 should be considerably more resistant to the etching solutions to be used later than the metal of the sheet 44. For the second metal, preferably those whose redox potentials are considerably lower than those of the first metal. If, for example, the first metal 44 is iron or steel, nickel can be used as the second metal 52 so that the sheet 44 is preferably etched in the subsequent treatment steps. The metal layer 52 may consist essentially of nickel-la Fhosphorlefcierungen, copper, chromium, cobalt, copper £ Kickellegierungen and cobalt-nickel alloys. The nickel phosphoric coatings preferably contain less than 20 percent by weight phosphorus. Furthermore, the metal of the layer 52 preferably has a melting temperature which is higher than the annealing temperature of the metal of the sheet 44 »so that it can withstand the temperatures during the subsequent annealing of the sheet 44 ·

The photoresist elements 40 are then completely removed from the first major surface 42 by solvents such as an alkali solution of KaOH. The photoresist layer 48 can be 40 protected from the alkali solution · Parts of the sheet 44 which now through the holes 54 in the metal layer 52 and the perforations 50 are open like in the photoresist film 48 are removed by etching during the removal of Elenente. If the metal of the sheet 44 is iron or steel, ferric chloride can be used as the etchant, and nickel, which is considerably more resistant to ferric chloride than iron or steel, can be used as the second metal for the layer 52. Electrolessly plated nickel is resistant to ferric chloride unless its temperature exceeds approximately 38 ° C (100 F.). Electroplated phosphorous nickel coatings show a similar behavior.

With a steel base with a thickness of approximately 0.15 mm (0.006 inch) the etch time is approximately 2 to 5 minutes for

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an aqueous ferric chloride solution of 40 to 45 trees, the Etch time changes with the temperature of the etchant. The etching can be carried out, for example, by spraying the etching solution on by means of a spray guns 60 take place. The parts of the Sheet metal piece 44 between perforations 50 in the photoresist film and the preliminary holes 54 are etched away in the metal layer 52, so that permanent holes 62 arise, the final width of which is greater than the width of the preliminary holes 54 · the relative extent and shape (i.e., substantially ellipsoidal) of the walls of the holes 62 are generally as shown in FIG. Preferably are the holes 62 and the corresponding preliminary holes 54 in the essentially in congruence with each other or concentrically. Because the second metal 52 is more resistant to chemical attack the etching solutions is as the first metal, the etchant only minimally affect the shape and dimensions of the preliminary Holes 54. Thus, the width of the phosphor elements 20, which are printed with the aid of these provisional holes 54, determined by the original size of the provisional openings.

A minimum width of the preliminary holes 54 (measured in the center of the screen) of approximately 0.3. ram (12 mils) and a minimum width of permanent holes 62 of about 0.4 mm (16 mils) provide satisfactory results «. A permanent hole width of about 0.4 mm (L6 Mil) produces a beam spot size at the screen of approximately 0.45 "ω (17.8 mil) and a width of the preliminary holes of about O ₅ 3 a 'a (12 mil) gives Phosphor element with a width of approximately 0 ₅ 35 sam (14 mil) ". Instead of the ellipsoidal wall shape shown here, the permanent holes 62 can also be made with other wall shapes (s" B _o essentially cylindrical, spherical or frustoconical).

As in Figure 5 geseigt _9, the PBaofcolacIcscfticlfrt; AB «it ζ« Β. a lye completely 'removed Metallusiterlage so that provisoiPi ^ che mask 64 ait both to preliminary gen holes 54 as atiefa larger' of the Permasientlöclhierüi 6% arises ο If the image of China foaibj an in wesesröljLchen spherically © or Arad »weitiig non-planar Fora, wispd the provisional mask © 64 -

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(with the metal layer 52) for example by annealing and pressing adapted to the general shape of the screen. The mask 64 is then by means of a suitable holder within a Cap 16 attached so that a temporary mask assembly is obtained. The invention is equally applicable to mask arrangements of planar and non-planar form.

To print the screen 24, the provisional mask 64, as shown in FIG. 6, is arranged at a distance from a suitable transparent plate 72 (for example the front plate 18 in FIG. 1). The preliminary mask serves as a photomask for the photographic printing of the color elements 66, 68 and 70 made of red, blue and green luminescent phosphors on the plate 72. A corresponding printing process is described in US Pat. No. 3,406,068. The transparent substrate is coated on one side with a light-sensitive mixture of a first of the desired phosphors and a suitable photoresist and then exposed, the light passing through the preliminary holes 54 of the temporary mask 64 in the same directions as later when the tube is in operation the electron beam in question. The parts of the light-sensitive fluorescent coating hit by the light rays are hardened. The uncured parts of the covering are then removed, for example by washing, so that a pattern or grid of phosphor elements mixed with the cured lacquer material remains. The same similar process steps are repeated for the phosphors of the other colors, the light source jet ^ Eils elsewhere is arranged so that corresponding grid of the other phosphors interwoven with the first color element screen, arise. The hardened photoresist material is then removed from the color elements by baking or chemical dissolution.

In operation the tube is located at points 76, 78 and 80 one beam system each for a corresponding color element grid, in essentially the same spatial relationship to The same screen as that for printing the relevant color element grid used light source, the optical paths of the light rays

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when printing and eier electron beams in the operation of the picture tube are indicated by lines 86, 88 and 00

Preferably, the provisional Mask 64 arranged so that the metal layer 52 peen the Light source is turned. This will cause more rays of light to collide obtained, which results in more sharply defined phosphor points. The relatively thin metal layer 52 results in holes 54 with razor-sharp edges, resulting in more sharply defined color elements or led fluorescent dots

In another embodiment of the method, the temporary mask to werdea used _for a screen with a light-absorbing matrix of opaque, non-reflective material covering to prepare the surface of the plate 72 between the color elements 66, 68 and 70 ,, This can be in such a way happen that first the surface of the transparent plate 72 is coated with a relatively transparent mixture which contains a material with relatively low Licfotabsorption, which can be converted into a highly absorbent state. A suitable material of this type is ζ “Bo ifaegan carbonate, which can be converted from a comparatively transparent, into a dark, light-absorbing state by thermal decomposition. The device also contains a photo-ink of the "positive type" (ie which becomes water-soluble on exposure). "The covering is then exposed to a suitable light source through the preliminary holes of the provisional mask 64 (FIG. 5). The exposed soluble parts of the covering are washed away so that holes arise in the covering, which is next converted into the light-absorbing state by heat treatment, so that a dark, perforated matrix is created. Then, with the help of the provisional mask, the colored elements 66 _g 68 mad 70 are printed on the stiffeners of the holes in the die, as described earlier _s to print by the Perraaneataaske at eatfermte ^ r metal layer 52 so that the edge portions of the esitsprecheiadesi Leiacfitstioffptmkte on dl ©

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BATH

Reach over the die itself. The "effective size" of these phosphor dots however, is equal to the size of the corresponding die holes. If desired, the fluorescent points can with the provisional mask can be printed before converting the matrix material into the light-absorbing state. Instead you can The phosphor dots are also printed before attaching the stencil, using the makeshift mask for making both the matrix and fluorescent points are used. The phosphor dots can absorb light using the the die can be printed on the surface of the plate after it has been applied. The fluorescent printing is done in the way that a phosphor-photoresist mixture in ■ the form of a layer on the exposed surface of the die is applied. This mixture covers both the template and the surface of the plate 72 exposed by the template holes. The fluorescent photoresist layer is then exposed by means of a light source on the surface facing away from the surface provided with the die other side of the pad is arranged. The light rays passing through the die holes print in the areas the die holes the phosphor dots.

After completion of the screen, the metal layer 52 is removed from the perforated base 44 so that the permanent mask electrode 30 results. When the layer 52 is off Nickel on iron or steel sheet 44, it can thereby I removed that the provisional mask 64 in a room temperature Maintained bath of 2 parts of water and 3 parts of sulfuric acid and with a counter DC voltage of -6 volts is applied.

Figure 7 illustrates a further embodiment of the invention Procedure. On a surface 102 of a sheet 104 of a first metal (e.g. steel) is a continuous Metal layer 100 (ζ · Β. Made of nickel) applied. The thickness of the layer 100 is preferably less than 1/5 the thickness of the Sheet 104. On the exposed surface 106 of the metal layer 100 a coating I08 from an iVtz-

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Protective agent attached, which is insoluble in the etchant to be used and contains a pattern of openings or holes 110 of a predetermined width. and includes holes 116 which are at least as large as and correspond to or coincide with the holes in the pad 108. Only those parts of the metal layer 100 that are accessible through the holes 110 in the covering 108 are then removed, for example by electrolytic etching with an aqueous ferric chloride solution as the electrolyte, the second metal being nickel or a phosphorus-nickel alloy, so that in the metal layer 100 preliminary holes (not shown) of a first size arise. These preliminary holes are substantially the same size and shape as the perforations 110. During the electrolytic etching, the surface 112 of the sheet 104 is protected. After etching through or somewhat beyond the phosphor-nickel layer 100, the electrolytic etching is terminated and the sheet metal 104 is subjected to a spray etching in the manner explained in connection with FIG. Instead, the etch protection coating 108 can be completely removed first and the etching of the metal base 104 can be pre-isolated through the preliminary holes (not shown) in the metal layer 100 and / or the perforations 116 in the etch protection film 114 in the manner explained in connection with FIG. This etching process gives the metal base 104 permeate holes, which are larger than the preliminary holes of the first size mentioned ofeera "The materials used and the etching as well as the subsequent process steps (shaping of the mask, new Schiradrwcken") as well as the relative size and shape of the holes rait of the final size are essentially the same as in the previously described AueffiforatagsfoiPsa of the method. ...

The present Verfahr® » for the breeding of the Bildsefeiraea picture tubes and for the production of the finished Farbaaskea soidl © di © made according to this process provisional mask siiad saifc © ines» series of advantages ,, especially & sa more economical ¹

bound. This includes the possibility of glowing and shaping the provisional masks with provisional holes without any significant harmful effects on the provisional mask. This enables the use of continuous manufacturing processes to generate temporary masks from strips of relatively hard conductor material. When using such hard strip material, the risk of tearing and / or deformation during the manufacture of the masks is very low, so that the production yield is relatively high. When using continuous manufacturing processes, the production efficiency is increased and the production costs per mask are reduced. Further advantages are that the provisional for perforated layers of Λ masks materials used (ie metals) are opaque in nature and therefore no special Opakisierungsmaßnahmen must be made and that these materials are sufficiently mechanically stable to normal handling, with little or withstand no damage at all while

they are nevertheless sufficiently pliable to withstand the subsequent shaping of the mask without damage. Furthermore, according to the method, temporary masks are obtained whose preliminary holes are more resistant to the wear and tear and the harmful effects of etching solutions. This results in preliminary holes, the shape and dimensions of which remain largely unaffected by the machining operations. This will give the printed using the provisional mask color elements uniform size \ and shape. In addition, considerably larger differences in size between the permanent holes of the final size of a color mask and the phosphor dots associated with these holes can be obtained (provided the desired picture tube operating tolerances are adhered to) than with the known methods. Furthermore, the screen printing process is considerably less sensitive to prevailing light distribution fluctuations than the known methods, so that there is a greater breadth in the choice of screen printing parameters. Finally, the exposure time for screen printing is not as critical as in the known methods, which makes the printing process easier.

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Claims (8)

Claims j (1 /. Procedure for making a provisional color mask for a color picture tube, with the provisional color mask from a thin piece of sheet metal with a pattern of openings and with a layer of material applied to one surface thereof with temporary openings that coincide with the openings in the sheet metal piece, but for printing fluorescent elements on the tube screen are smaller than the corresponding openings in the sheet metal piece, is characterized by that a surface (42) of a piece of sheet metal (44) is coated with a metal layer (52) with a pattern of preliminary openings (54) wirdj that the other surface (46) of the sheet metal piece with an etch protection film (48) with openings (50), which cover with the preliminary openings (54) in the metal layer (52) and essentially the same size as these preliminary openings, is coated) that by etching away the through the Openings in the metal layer and in the etchant film exposed Parts of the sheet metal piece in this permanent openings (62), which coincide with the preliminary openings in the metal layer and are larger than these are formed ^ and that finally the anti-etching agent fila from the other surface of the sheet metal piece Will get removed. 2. The method according to claim 1, characterized in that that in order to form the perforated metal layer (52) first of all the one surface (42) of the sheet metal piece (44) is coated on a film of photoresist material and the photoresist film is photographically coated into a pattern of photoresist elements (40), which is only part of the surface © of the sheet metal piece cover, is formed that the remaining exposed part of the surface of the sheet metal piece is charged with a metal layer (52) tet is} and that the photoresist elements forming the pre-. running openings (54) in the metal layer are eatferirrfc » 3 · Method according to claim 1, characterized in that g © k e η 0- 009882/1512 BAD ORIQtNAl. shows that the first one surface (102) of the Sheet metal piece (104) is coated with a continuous metal layer (100); that the surface of the continuous metal layer coating with a photoresist film (108); that on photographic one Forming a pattern of openings (110) in the photoresist film exposing portions of the metal layer; that the exposed portions of the metal layer are etched away to form temporary openings (110) in the metal layer; and that the photoresist film (108) is removed. 4. The method according to any one of claims 1 to 3,. through this characterized in that the metal layer (52) and the sheet metal piece (44) consist of different metals, ™ and dall the openings (62) through the sheet metal piece (44) selectively with it an etchant can be etched with the metal of the metal layer chemically does not react. 5. The method according to claim 1, characterized in that the metal layer (52) consists of electroless plated Nickel or a nickel-phosphorus alloy and the sheet metal piece (44) consists of an iron alloy or steel; and that only the sheet metal piece (44) with a ferric chloride solution is etched at a temperature below 38 ° C (100 ° F). 6. The method according to claim 3 »thereby g e k e η n- | shows that the metal layer (100) is made of electrolessly plated Nickel or a nickel-phosphorus alloy and the sheet metal piece (104) consists of an iron alloy or steel; and that the exposed parts of the metal layer (lOO) with a aqueous ferric chloride solution ale electrolyte is electrolytically etched away and then the sheet metal piece (104) «with a ferric chloride solution at a temperature below 38 ° C. (100 ° R) is etched, 7. A method of manufacturing a screen for a color picture tube with faceplate using the according to claim manufactured temporary color mask, thereby ■ ':. ". 009882/1512 BAD ORiGtNAL characterized in that one surface of the faceplate with a film made of a material with low light absorption, but which can be converted into a highly absorbent state and which is mixed with a photoresist, which becomes soluble on exposure, is coated on that part of this film exposed through the provisional openings (54) of the provisional mask (64)? that the film forming the faceplate surface developing openings exposing the exposed areas; that the material of the film in a highly absorbent The condition is that the perforated film is covered with a coating of a mixture of a photoresist and fluorescent material that this coating is covered by the faceplate and the openings of the light-absorbing film or by the preliminary ones Exposing openings of the temporary mask; and that the photoresist-phosphor coating is developed such that Phosphor remains only within the openings of the light-absorbing film. 8. The method according to claim T _3, characterized in that the metal layer (52) is removed from the sheet metal piece (44) after the exposure of the film parts through the preliminary openings (54) that the photoresist-phosphor coating is exposed through the permanent openings (62) of the color mask | and in that the photoresist phosphor coating is developed in such a way that phosphor elements remain which cover the openings in the light-absorbing film and parts of the film surrounding these openings. 2/1512 BATH ORIGINAL Blank page