CA1316977C - Process and apparatus for the manufacture of cathode ray tubes having tension masks - Google Patents

Abstract

ABSTRACT
This invention relates to a reusable factory fixture frame and process for using same in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask. The frame provides for mounting an in-process shadow mask during photoexposure of an in-process faceplate in a lighthouse.
The frame comprises generally rectangular frame means and quick-release mechanical mask-retaining means for temporarily and removably supporting an in-process shadow mask in tension. The frame includes a generally rectangular frame structure having grooves thereabout for receiving an edge of the shadow mask. The mask retaining means may comprise spring-loaded mechanical mask-retaining devices which are secured to the side of the factory fixture frame for temporarily and removably supporting the in-process shadow mask in tension in the grooves. The shadow mask is heated and allowed to expand prior to being temporarily and removably supported on the frame, and the shadow mask is allowed to cool and shrink in tension while so being supported to effect tensing of the shadow mask in clamped condition on the frame.

Description

13~6~7 This invention relates to color cathode `~ ray picture tubes, and is addressed specifically to improved factory means and processes for th.e manu-facture of tuh~.s,, h.~yin.g a tensed ~Qil ~ado~ mas.k..
5 Color tub.es o~ var~Qu~ t~es t~at h.ave, ~ tens,ion ~oil mask can ~e manufactured by th.e process:r including th.ose used in home entertainment televi`sion recei~vers.
The process according to. the ~nvent;on is particularly valuable in the manu~actuxe o~ med~.u~-re~olution, h.igh-~ lO resultion, and ultra-hi~h resolut~Qn~tube~ intended for :,; color monitors., me use of the:.foil-type flat tensed mask and:
flat faceplate provides many ~enefits i.n comparision to the conventional domed shado~ ma$k.~and~ correlatively~
15 curved:faceplate~ Ch.~ef amon~ th,ese is~a greater power-handling:capability w.~ich.makes possible:as much.as a : three-fold increase in brightne~$. The conventional ,~ ~ : curved shadow mas~, wh.i.ch:is not under te.ns-`on, tends .~ :. to "dome" in p:icture areas of hi.gh.br~ghtness where the 20 intensity o~ the electron heam bom~ardment is~greatest.
C~lor impuritieR res~ult.as~the ~ask~moves closex to the aceplate ~nd as:th.e b.eam-passing-apertures move out of reglstration with t~eir associated~phosphor elements on :: the facepl~ate. The te.nsed:~as~ ~:en heate.d dis-t~rts~
25 in a manner ~u~te,di.f~exent fr~m~the con~entional mask..
If;~the ent~re mask ~s heated uni~o~mly~ thère i~ no doming and no dist~rt~on unt;l tens~ion is completely lost: just ~e~re that point, wrinkl~ng m~y~:occur in the corners. I~f only portions ~f t~e mask are h.eatea, those ~31~77 -- 2 ~
portions expand, and the unheated portions contract, r~sulting in displacements within the plane of the mask;
i.e., th.e mask remains flat.
Th.e tensed foil sh~dow mask is a part of the 5 cathode ray tu~e ~ront assemb.ly, and is located in close adjacency to the. faceplate Th.e front assembly comprises the faceplate with its~ screen which consists of deposits of light-emitting phosphors, a shadow mask, and support means for th.e mask.. As used herein, th.e 10 term "shadow mas:k." means an apertured metallic ~oil which. may, hy ~a~ of example, he about 0..001 inch.or less in th.~ckness~. The mask must be supported under high tension a predeterm~.ned di`.stance from the inner sur~ace of t~.e cathode ray tube ~aceplate; this distance 15 is known as: the "Q-distance." As. is well known in the artt the shado~ mask. acts as a color-selection electrode, or parallax barri.er, w.~ch ensures that each oE the three electron ~eams. lands~ Qnly on its assigned phosphor de-posits. :
. 20 The conventional process of depositing pat-;I terns o~ color phosphor elements on th.e screening surface of a color picture tube f~ceplate utilizes th.e well-: known photoscreening process. ~ sK.adow mask, which in effect functions as a perforated optical stencil, is 25 used in conjunction ~i.th a light sou~ce to expose in successive steps, three di~crete ligh.t-sensitiye photc-; resist patterns: on the s.cxeening s.urface. Th.e sh.adow :: ~ mask is typic~lly "~ated" to eac~.faceplate; that is, the same mask.~ u~.ed ~n th.e pxoduction o~ a specific : 30 tube throughout the producti.on process, and is permanently installed ;n tK.e tube ln final assem~ly. At least four engagements and four d~sen~age~ents o~ the mask, as ~ell as six expos:ures, are re~uired in th.e standard screening proces~ n certai.n processes, a "master" may be used 35 for expos.~n~ thQ phDtoresist patterns in lieu of themated sh.adow mask..

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:~3~77 There have been a number of disclosures of tensed ~oil masks ~nd means for applying tension to the mask and retaining the mask under tension. T~pical of these is the disclosure of Law in U.S. Pa~ent No.
3,625,734 ~hich.address:es the. construction of a taut planar foraminous mask. A foil mask hlank is loosely mounted in a two-section frame, and t~e mask is expanaed by the hot-~locking process. Mach.Xne screws peripheral to the frame prov~de for clamp~`ng the. mask tightly in the frame wh.en the ~ask i.s ~n Its expanded state. The mask becomes tensed upon cooling as it is restrained from returni,ng to ~,ts former dimens~ons by ~ts captiva-tion by th.e frame. Th.e frame.~th t~e mas:k enclosed is mounted with th.e phssphor-~earing sc re.en as a unitary assem~ly adjacent to th.e ~nner surface o~ the ~aceplate.
Law in U.S. Patent No. 2j654,940 also discloses means for stretching and captivating b~ frames masks ormed from:wire mesh.. ' U.S. Patent No. 3,894,321 to Moore, is directed to a method for procèssing a color cath.ode ray~ tube faceplate in conjunction with.a thin fo~I tens~on shadow mask.. ~ fr~me scre~-clamp s:upports a tensed mask during lighthouse exposure'o~: an associated screen.
The facepIate i5 registerea with th.e mask.support frame by means: o~ three al~gnment p~sts ~ich extend from the lighthouse, and agains~t w.hich th.e fxa~e:and th.e faceplate are both biased ~b.~ gr~Yity. The. ~cepIate and frame, being~oth.re~e~ence.d t~o, th.e. thxe.e lighth.ouse posts, are thereby:referenced to each.'other.
, In U.5. Patent No. 4,591,344 to Palac, a meth.od of making ~ colo~ ca,thode ray tube i.s d;sclosed in which a frame on whi,ch a s.h~do~ mask is stretch.ed h.as indexing ~.
means coope~ab.le ~ith.~e~stxatiQn-afford;'ng means on a faceplate. Th.e;assem~.ly pxoY~de~ fox mult`ple registexed matings. of th.e faceplate and mas:k durin~ p~otoscreenlng ::
operations. A p~Dtograph~.c plate ~s used in a process for applying the phosp~or elements: to t~e ~aceplate "

scre6~ing surface to provide an interchangeab.le mask system; this in lieu of the more common method of using a shadow mask.permanently mated with.a faceplate, and - which serves as an optical stencil during the photo-5 screenlng process:0 Th.e sealing areas o~ the faceplate andtheframe are joined in a final assernhly operation such that the frame ~ecomes an integral constituent of the cathode ray tube.
~ mask re~istration and supporting system for 10 a cathode ra~ tube having a rounded faceplate with.a skirt for attachment to a funnel Is disclosed b~ Strauss in U.S. Patent N~. 4,547,6q6~ The sk.irt of the face-plate prov~des th.e necessary Q-distance between th.e mask and the screen. A frame d.~mensioned to enclose the 15 screen compris:es. first ~nd s:econd spaced~apart surfaces.
A tensed foil shado~ mas~ h~s a periph.eral po.rtion b.onded to a second suxface of the frame. The fra.me is registered with th.e :faceplate B~ ~all-and-groo~e ~ndexin~ means.
e shadow mask is sand~iched b.etween the frame and a 20 stabilizing or sti.ffening mem~.er. Follo~.ing final as:-sembly, the. fra.me ~ permanently fi`xed in place with.in the tube envelope b.et~en the sealing lands of the face-plate and a funn.el, ~th.a stiffening mem~.er projecting ~ from the frame into th.e funnel.
: 25 In U.~. Patent No. 4,593,224 to P~lac, there is disclos.ed a shadow:ma$k.~unt in the $hape o~ a rec-tangular frame fQr us:e in tens:in~ an i.n~proces~ shado~
mas.k~, and for temporar~ly sup~oXting the rna$k.while in tension. An apertured fo~l:compris~ng th.e in~process 30 mask is ~aid ~cros:s th.e openi:ng in thR ~rame and is : ~ : secured to the. frame~ bxaz~.n~ or welding. The co~
: efficient o~ thermal~ expans~n of the foil is pref-.~ erably equal:to .~r s.lightly les.s th~n that of the fra~e.
A glass fra~e is als.a proyi~ded that con$ists of t~o 35 identical rect~ngular mem~ers ~maller in circumferential dimension than the` metal fra~e. ~.hen joined into a s:ingle ; frame, the mem~.ers are located ~.et~een th.e tu~e faceplate ' ~316~7~
-- 5 --and funnel to become an integral part of the tube en-velope in final assem~ly. Each.member o~ the glass frame has index.i.n~ means, one member for indent-de-tent registrati.on with.the faceplate, and the other for 5 indent-detent registration ~i.th the funneI. Following the application of a l~yer of devitrifying cement in paste form to the fac~ng surfaces of the two members, the mask, held in the metal frame, is sandwiched be~
tween the two memb.ers:. ~s the assembly is heated, the 10 expansi,on of the mask is taken up hy screw means attached to the metal fra~e w.hich ~ress against the periph.eries of th.e memb.exs. Upon cooling of the assembly, the co-eficient of ther~al expansion of th.e mask b,eing great-er than that o~ the glass:, results in the mask being 15 held permanently i.n tension b.~ the ~lass frame through , the,medi~ of the f,r;t cement, which,has: become s:olidified by the heat. The porti.on of th.e mask thàt projects beyond the periphex~ ~f the gl,ass, frame is severed to release the metal frame. The gla$s frame with its cap-20 tivated mask. is then mounted on ~ lighth~use for photo-'.~ screening the faceplate, ~th registration with~the lighthouse ~nd faceplate provided hy the indent-detent means described.;
In a journal articIe, th.ere is described means 25 for mounting a flat tensed mas,k on ~ fr~me for use in a color cathode xay tube having a circular faceplate with a curved Yie~ing s;urface. In one embodiment, the mask, ~hich is als~ c,i~cular, is describ.ed as being welded to : a circular frame compx~s.ed of ~ I/8-inch steel section.
: 30 The frame with captivated mask is mounted ~n spaced relationship to a phosphsr-dot plate, and the combin~
tion is as;sem~led ~nt~ the tu~.e a$ a packa~e located adjacent t~o, the face~late.. ~"Impxovements in the RCA
Three-B..ea~ S~ado~ Mas:k Colo~ K~'nescope," ~.~ Grimes et ': 35 al. The I~E, J~nuar~, lq54; decimal classification ~ R583-61.

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In general this invention aims to provide means to facilitate the manllfacture of color cathode ray tubes having a tensed foil shadow mask by providing improved fixturing means that will greatly facilitate this manufacture.
The present invention therefore provides a reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for temporarily mounting and conveying an in-process shadow mask for processing by manufacturing machinery, said frame comprising a generally rectangular frame means having a first side and an opposed second side, at least one of said sides having at least first and second six-point indexin~ means azimuthally rotated with respect to each other for indexed mating with complementary six-point indexing means on said manufacturing machinery.
The present invention also relates to a reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for temporarily mounting and conveying an in-process shadow mask for processing by manufacturing machinery, said frame comprising generally rectangular frame means having six-point indexing means on a first side for indexed mating first with complementary six-point indexing means located on means for mask tensing and clamping, and subsequently with indexing means located on a lighthouse, and six-point indexing means on a second, opposed side for indexed mating with complementary six-point indexing means on an in-process faceplate.
A related aim is to provide an improved process for the manufacture of color cathode ray tubes.
The present invention therefore provides a process for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask, said process inclu~ing the steps of providing a , . ....
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_7~ 7 reusable, generally rectangular factory fixture frame having releasable mask-reta;ning means, temporarily and removably supporting an in-process shadow mask in tension on sa;d frame with said releasable mask-retaining means, providing a faceplate having indexing means e~tending from the side thereof for registration with indexing means extending internally from said factory fixture frame, providing a shadow-mask-supporting structure and securing said structure to the screen-bearing surface of said faceplate on opposed siaes of the screen, affixing said in-process shadow mask in tension to said supporting structure, and severing the combined mask-faceplate assembly from said frame thereby releasing said frame for reuse.
The present invention also relates to a process for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask, the process comprising providing a reusable, generally rectangular factory fixture frame having quick-release mechanical mask-retaining means~ temporarily and removably supporting an in-process shadow mask in tension on said frame by said mechanical mask-retaining means, providing ~ on a first side of said f~ame si~-point indexing means ; and, using said indexing means, registering said frame and said mask with a photoexposure lighthouse having complementary six-point indexing means, providing on a second, opposed side of said frame six-point indexing means, and registering said frame and said mask with means for affixing said mask to a mask-supporting structure on said faceplate, affixing said mask to said mask-supporting structure, and severing the combined mask and faceplate assembly from said frame thereby releasing said frame for reuse.
~: Another feature of the invention is the provision of a factory fixture frame that is capable of highly precise and repeatable two-sidPfl registration with a ~ ' -7a- 13169~7 lighthouse and a faceplate during faceplate photoscreening, and precis registration with a mask-welding and severing machine.
Still another feature of the invention involving a factory fi~ture frame including tensed foil in-process shadow mask clamping means for quickly and securely clamping and retaining a shadow mask under high tension without damage to the mask~
In general the factory fi~ture frame of the invention is rigid in construction, reusable, and relatively light in weight for easy handling.
Further features and advantages of the present invention will best be understood by reference to the following description of preferred embodiment o~ the invention taken in conjunction with the accompanying : drawings (not to scale~, in the several figures of which like reference numerals identify like elements, and in which:
~ Figure 1 is a side view in perspective of a :
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~31~977 color cathode xay tu~.e having a flat faceplate and a tènsed foil shado~ mask, with.cut-away sections that in-dicate the location and relation of th.e faceplate and sh.adow mask to oth.er ma jor tuhe components;
Figure. 2 i~ an obl~.que Yiew in perspective of a fac~ory ~ixture fr~me according to th.e invention with an in-process shadow mask mounted in tension th.erein.
Figure 3 is a view in elevation and in perspective of a mask tens.in~-clamping machine for re-10 ceiving a facto;ry fixture fra~e according to the invention;
Fi.gure 4 is a plan y~ew of an in-process: shadow mask;
Figure 5 ~s: a pe.rspective view that depicts 15 schematic~lly th.e mountin~ of an in-process shadow mask on a platen.
: ' Fi,gure 6 i.s a pl~n View of a first side of a factoxy fixtuxe.~xa.me accpxdi,ng to th.e. ~nyention and showing details of indexing means;
Figure 7 is a vîe~ similar to th.e figure 6 - view, but showing a s.ecQnd side of a f~ctory f;xture frame accordtng to th inYentiQn, and showing additional details of inde~ing me~ns.;
: , Figure 8 i~ a perspective view: of a photo-25 exposure ligh.t~ou~e ~ith the ~ase partly cut away, and ' wi,th the factoxy fixture frame according to the invention and an in-process f~ceplate indicated as: being exploded .~` there~ro~; ,~ .
Figure 9 i~ a plan vi.e.~ of an in-process face-30 plate showing th.e screeni.ny area, a shadow mask support, ':: and indexi:ng means extending from the sides th.ereof;
: :~ Fi~uxe lQ i,s: a view in perspective that de-: picts di.~gr~atic~lly~ th.e means ~ox mounting:and reg-~; ~ istering the ~ctoxy ~ixture ~ra,~e according to th.e in- :
~ 35 ventiQn w~ith ~e~ns- f~r ~ask ~elding and severt.ng;
: ~guXes: llA ~nd llB.are secti~nal views in ~ :

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~ 3 ~ 7 g elevation taken along lines A-A of Figures 10, and showing the sequence of precision registration of the factory fixture frame according to the invention with means for mask welding and severing.
~ To facilitate understanding of the factory fixture frame and its relation to the process of manufacturing a tensed mask cathode ray tube, a brief description of a tube and its components is provided in following paragraphs.
A color cathode ray tube 20 having a tensed foil shadow mask is shown by Figure 1. The front assembly 22 of tube 20 includes a faceplate 24. On the inner surface 26 of face-plate 24 --known as the "screening surface"-- is indicated as being deposited a phosphor screen 28. A film of aluminum 30 is indicated as covering the screen 28. The peripheral sealing area 32 of faceplate 24 is depicted as being t' : attached to the peripheral sealing area 33 of a funnel . : 34.
Front assembly 22 includes a shadow mask .
: : support structure 48 for mounting a metal foil shadow mask 50 which is secured to support structure 48 in tension.. The anterior-posterior axis of tube 20 is indicated by reference number 56. A magnetic shield 25 58 is shown as being enclosed within funnel 34. High â
: voltage for tube operation is indicated as being : applied to a conductive coating 60 on the inner surface .
~ ~: of funnel 32 by way of an anode button 62 connected : :
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in turn to a high-voltage conductor 64.
Th.e neck 66 of tube 20 is represented as enclosing an in-line electron gun 68, depicted as providing three discrete. in-line electron beams 70, 5 72 and 74 for exciting reSpective red-ligh.t-emitting, :~ green-light-emitting, and blue-light-emitting phosp~or elements on screen 28. Yoke 76 receives s-canning signals and provides ~o,r the scanning of ~eams 70, 72 and 74 across screen 28. A contact spring 78 10 provides an electrical path.~e.tween the funnel coating 60 and mask. support structure 48.
The factory fixture ~rame according to the invention proYides for the h.ig~.precis~ion i.n th.e reg-istration and re-regi.stration of a ~oil in-process 15 Shadow mask with.a Eaceplate during manufacture. Ab-sent the requisite Preci$ion, an error in registra-tion of a,s, little as ~.QO.Q2 inch can result in color impuriti~es. Mas.k 0.-typically-may h~ve a~out 1,700,000 apertures, and the resulting screen 28, after photo-20 screening by means- of the factory fixture frame ac-cording to the~i.nventi.on, will ~.ave three times as many discrete phosph.or deposits t~ereon. There is an absolute minimu~ of tole.rance in registration at any stage of the product~on process.
A resuable factory fixture ~rame 82 accord-ing to the. invention is shown in Figure 2; a first . side 84 of frame 82 i.s indicated. The frame 82 is intended ~or u$:e in t~e ~,a,nufacture ~ a color cathode - ray tube of the type s~own by Figure 1, which is noted , 30 as having a flat faceplate and a tensed foil shadow :~ mask. Factory f~xture ~rame 82 provides for mounting an in-proce$-$. shadow mas:k dur~ng photoexpos:ure of an :~: in-proce.~s ,faceplate ~n ~ l,ig~thouse, and serves as a ~: : fixture for the. proce.iss o~ ~eldin~ and severing the j : 35 in-proce.ss ma~., a,~, will be.de$cribed. A$ depicted in '~' ,.
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``~ ;, ~31~7 Figure 2, reusable factory fixture frame 82 comprises a generally rectangular frame means and quick-release mechanical mask-retaining means for temporarily and removably supporting in-process shadow mask 86 in tension.
5 Frame 82 is indicated as supporting shadow mask 86 in tens.ion by ~eans of mechanical mask-retaining means 88.
Factory fixture frame 82 provides for the cementless and weldless quick-retention of in-process shadow mask 86 out of the plane of mask 86.
The factory fixture frame 82 will be noted as having handles ~OA, 90B and 90C for convenience in h.andlin~ during manufacture. Handles 90A and 90B pro-vide for lifting the frame, and handle 90C provides for inserting and removing the factory fixture frame 82 from 15 the mask. tensing-clamping machine 96 depicted in Figure 3. The mask. tensing-clamping machine 96 provides for receiving th.e factory ~ixture frame 82, which is loaded into the ~ask tensing-clamping machine g6 by an operator , :: using th.e handles described; the factory fixture frame ~0 82 is indicated in Figure 3 as ~eing mounted in machine 96, and ready to tense and clamp an in-process shadow mask.. Mac~ine 96 is indicated as ~.aving an upper platen ; lO.Q and a lo~er platen 102. The platens are heated to provide for expansion Qf the mask ~lank prior to the ~: 25 clamping operation.
An in-process a~.adow mask is depicted in Figure 4. In-process mask 86 comprises a center field lQ4 of apertures intended for the color sele.ction : ~function in the completed tu~e. Center field 104 is 30. indicated as ~eing enclosed ~y a frame 106 ~f u~ erforated :~ ~etal; this frame is trimmed off in a later operation at trim line 108, ~ndicated by the dash.line, b~
means that ~ilI he descr~hed. In-process mask 86 i.s indicated as ha~ing a round perforation 109 in 35 ~ra~e 106, ~nd an elongated perforation 110 opposite. As ; , :

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depi.cted i,n Fi~ure 5, the per~orations 10.9 and llO
provide for registexing the in-process mask 86 ~ith.
respective pins 112 and 114 that project from lower platen 102. Th.e elong~ted per~oration 110 pxovides 5 tolerance for the. expansi,on of the in-process ~ask resultlng from its contact ~ith.th.e heated plate.ns lO0 and 10.2, an expans;`on that is on th.e order of 0.030 inch..
~ ~en the. in-process mask 86 is ~ully expanded :~ lO by the he.at o~ upper and l,o,wer platens lQ0 and 102, the mask. i$. cla,mped, and th.e. ~latens are withdrawn. The mask. tenses a~ i,t cools,, and it i$ held in tension by the clamping means 88 th.at are.aj compone.nt of f~ctory ~ixture frame 82, as: wi,11 b.e described, ' 15 Factory fixture frame 82 has two sides o~
; interest: ~irst side 84, depicted in Figures 2, 6 and 10 and a second s~de 118, depi.cted in Figures 7 and 8.
~ith. reference to ~igure 8, ~rst S.ix-pQint indexing means on first slde 84 provide ~or registration with.' 20 complementary registratiQn-a~fQrding means on an ex-. posure ligh.thou~e 122~ and second $ix-point indexing means on an oppQsed second s~de 118 pxovide for reg-istration w~th complementar~ re~istration-affordin~
~, means on an in-pxocess faceplate 120... As a result~
.~ 25 in-process: shado~ mas;k.86 can be precisely registered and re-registe.red ~ith ligh.thDuse 122 and an in-process faceplate 120 ~hi.le retaining the in-Process shadow mask 86 in tensi~n. Th.e f~i,rs~t si~-point indexing means on t'h.e first s~de 84 also prov~de for register-,~ 30 ing the frame 82 and in-pr~cess s~adow mask 86 with mask ,: tensing and clamping means, noted as being mach.ine 96, ~: ~ which.h~s complementary six-point indexing means, as ~; will be described.
The.clampi~ng means: 88 for clamping and holding ' ~
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in-process mask 86 in tension is depicted in Figure 6 as being in the form of a series of discrete spring clip means which provide for mechanically clamping the mask in tension. The factory fixture frame, while clamping the tensed in-process mask, is removed from the mask tensing-clamping machine 96 in readiness for subsequent photoexposure and screening operations, as will be described.
Photoexposure ligh.th~use 122 is illustrated schematically in Figure 8 as comprisiny a base 124 within which.is: a ligh.t source 126 that emits ultra-violet radi~tion to ~hich.th~ various screening fluids are sensitized. Th.e rays of th.e ligh t source 126 typically pass through.a correction lens and a neutral density filter (not shown~ before reaching the shadow mask. A table top 128 provides for mounting a plat-~ form 13Q for receiving factory ~ixture frame 82.
;~ : The s~x-point indexing means is depicted b.y way of example as: comprising ~all-and~groove means located on th.e parts to he registered. Although ball-and-groo~e indexing means are depicted for this means of indexing in this, and in subsequent depictions, it is noted that other ~eans of indexing may as well be used.
.~ :25 With.reference to the first side 84 of : factory fixture frame ~2, three groove means 132~, : : 132B and 132C are shown; these groove means providefor registr~tion ~ith. thxee ball means:134A, 134B
; and 134C located on ~latform 130 of lighthDuse 122.
As indicated b~ ~igu~e 8r the factory fixture frame 82 : according to th.e inYention is lowered into registration : ~
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:~w f~
A ~ with the li.ghthDuse 122 for exposing the screening surface of in-process faceplate 120 to radiation from light source 126.
Groove means 132A, 132B and 132C also pro-5 vide for the registration of factory fixture frame 82 with the mask tens~ng-clamping machine 96 in conjunc-tion with six-point indexing means 135A, 135B and 135C
depicted in Figure 3 as being in the form of ball means projecting from the lower platform 137 of 10 machine 96, (~all means: 135C is not visible in Figure 3.) Factory fixture frame 82 according to the invention is noted as havi,ng on its: second side 118, second six-point indexing means for registering with complementary registration-affording means on the in-process faceplate lS 120. The indexing means are indicated as comprising ' ball-and-groove means located on th,e parts to be ,~ registered. With refexence to the.second side 118 depicted in Figure 7 three groove means 136A, 136B, and 136C are depicted; these groove means provide for 20 registration with. three halls means 138A, 138B and 138C
~: extending from the s:i.des of faceplate 120, as de-. picted în Figure 9. The bail means 138A, 138B.and 138C comprise temp~rary indexing means. The cement used for attachment of the tempQrary indexing means is s 25 of th.e type that ~ec~mes non-adherent at the frit ~: cycle temperature of 435 degrees C. As a result, the ball means f~ll a~ay from th.e faceplate at the time ~, of final ass,emb.ly, .~:t ~ill b.e obseryed th.at at least .~ ~ one of ~he si.des of the factory~f.~xture frame ac- , 30 cording to the invention has at least fi.rst and second: ,' :: six-point indexing means a~imuth.ally rotated with.re-'~ . spect to each.other for indexed mating with.comple-mentary six-poi.nt ~,nde~ing ~eans on manuf~cturing ma-: chinery, ~i.t~ t~e ~anuf~cturin~ mach~nery noted as 35 being ~ hth,~use in th.ls phase of th,e process. .

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Plastic guides 140, indicated as being eight in number, provide for guiding in-process faceplate 120 into recess 141 of factory fixture frame 82, with the final, precision registration being provided by grooves 136A, 5136B and 136C in registery with ball means 138A, 138B
and 138C that extend from in-process faceplate 120.
In-process faceplate 120 has on its inner surface 142 a screening area 144 for receiving discrete deposits of phosphors. A shadow mask support structure 146 has 10 surface 148 for receiving and securing in-process shadow mask 98 in tension by means to be described. The phot-screening process then follows. The inner surface 142 of the in-process faceplate 120, noted as being the screen-ing surface, is firs-t coated with a light-sensitive ma-15 terial. With reference to Figure 8, the factory fixtureframe 82 according to the invention , with the in-process shadow mask mounted in tension therein, is installed on th.e platform 130 of lighthouse 122, with precise registra-tion of the first side 84 of frame 82 being provided by 2a groove means I32A-C in conjunction with ball means 134A-C, wh.ich are located on ligh.thouse platform 130. The in-process. faceplate 120 is in turn mounted on the fac-tory fixture frame in precise registration with the cap-tivated mask using groove means 136A-C on the second side ; 25 118 of frame 82 in conjunction with ball means 138A-C that extend from the sides of faceplate 120.
The screening surface 142 of faceplate 120 is exposed ~o ligh.t actinic to the coating through each of the apertures in the in-process mask 86. Faceplate 120 30 is then removed from lighthouse 122 to "develop" the coating. As a result of thé preceding steps, a "grille"
~: is formed on th.e screening surface 142 which has three open are~s. in correlation to each aperture of the shadow mask. Th.e opening provide for receiving sequential 35 d~posits o~ red-light-emitting, green-light-emitting and blue-ligh.t-emitting phosphors. The aceplate is coated ~ith.a slurry containing phosphor which may comprise, by way of example, a phosphor that emits red light when ~' ~ '~
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~L3~977 ;~ J6 eY~cited by an electron beam. The faceplate is replaced in the lighthouse in precise registration with the in process shadow mask, and the coating is exposed to light projected through the apertures of the mask from a light 5 source located at a position that corresponds to the emis-sion point of the particular electron beam that is intended to excite the red-light-emitting~phosphor. The light, in effect, "hardens" the phosphor so that lt will remain : in place during a subsequent washing process.
~ 10 Th.e foregoing steps are repeated in turn t.o : deposit the green-ligh.t-emitting phosphor and the blue- I
~ li.gh.t-~mitting phosphor in the respective openings in the grille. At least four such engagements and disengage-ments of the mask are required in the screening process.
15 The final product is a faceplate having on its screening area 144 a pattern of groups of dots or lines capable of . emitting U~on excitation by electron beàms red, green or blue light; this area comprises the screen 145. It is to be noted that, in this process, an in-process shadow 20 mask~is typically "mated'l with.an in-process faceplate;
th~t is, the same mask is used in the photoscreening of a particular faceplate, and is permanently installed in conjunction with the faceplate in final assembly.
Upon completion of the photoscreening process, 25 th in-process. shadow mask 86 is affixed to th.e mask-receiving surface 148 of the shadow mask support struc- 3 ture 146j and th.e mask 86 is removed from the factory .~
fi~tu~e fra~e 82. The apparatus and process however, is descri~ed in th.e following paragraphs in some detail in : 3Q cannection ~ith.Figures 7, 10 and 11 to facilitate a fuller unders.tandin~ of the form and function of the factory : fIxture frame according to th.e invention.
: With.reference to Figure 7, the second side 118 of factory fixture frame 82 is depicted as having 35 third six-point indexing means 152A, 152B and 152C, ... .

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. ': ' ' ' ' ' . ' ' ' , ' ' .. ' ' ' ,~ J~ ~3~6~7 depicted as being in the form of radially oriented grooves.
Second side 118 is also depicted as having fou~th six-point indexiAg means 154A, 154B and 154C, depicted as being in the form of ball means projecting from :Erame 5 82. Third and fourth six-point indexing means provide for gros~ and fine registxation, respectively, of factory fixture frame according to the invention and an in-proces:s- mas.k. ~ith assembly means for affixing the mask to mask-support means extending from and secured to the 10 faceplate, as will be shown and described.
~ ith.reference now to Figure 10, there is in-dicated diagrammatically a receiving fixture 156 which is a part of a mask.welding and severing machine (not sho~nl. The m~ch.ine includes a carousel which rotates 15 to four stations in the process of welding an in-process sh.adow mask h.eld in tension in th.e factory fi~t~re frame to a mask support structure, and severing the re-sulting mask-faceplate assembly from the frame. In consequence of this process, the factory fixture~frame 20 is released for the temporary installation of a new in-process mask, and the faceplate assembly is released for attachment to a funnel.
Receiving fixture 156 is indicated as having three indexing means 158A, 158B and 158C represented as : 25 being in th.e form of ball means extending upwardly from fixture 156. Indexing means 158A, 158B and 158C provide fo.r indexi.ng ~ith.complementary six-point third indexing means. 152~, 152B and 152C located on the second side 118 o~ ~actory fixture frame 82 (see Figure 7); index:ing 3~ means 15~A, 152B and 152C are indicated as being in the ~ : ~form of radially oriented grooves. These indexing means .: provide ~or th.e gross registration of th.e factory fix-. ~ ture frame 82 and the enclosed in-process shadow mask 86 w.ith .t~.e mask welding and tensing machine. Installation 35 of the fr~me 82 on receiving fixture 156 is accomplished ~ manually b.y mea~s of the handles 90A, 90B and 90C.
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The precise configuration of the shadow mask receiving surface 148 in relation to the ball means 138A-C of the in-process faceplate 120 is mapped by optical means in the second station (not shown) of the mask weld-5 ing ~nd severing machine. The receiving fixture 156, with the factory~ fixture frame 82 mounted thereon, is then rotated to a third station of the mask welding and sever-: ing m~chine along with the in-process face-plate 120.
At th.is third station, fine registration means are brought 10 into play to ensure exact and precise registration of the -~ clamped-in mask.with.in-process faceplate 120, and to pre-sent the ma~k.recei.ving surface 148 ;`n a precise relative relationship In order to utilize the above-described : :.napping information to effectively drive the welding 15 head at t~ mas:k.welding and severing machine.
~ ith. referénce again to Figure 7, th.e fourth "finel' registration means compr~se six-po~nt indexing means 154A, 154B.and 154C, depicted as comprising three ~;; ball means extending from th.e second side 118 factory : 20 fixt~.e fxa~e 82. Complementary to six-point indexing b~ll means 154A, 154E and 154C are t~.e associated sIx-point indexing means 16QA, 160E and 160C, indicated ~: in Figure lQ as compr~ing groove means located atop respecti.ve ram heads 161A, 161B and 16].C all three of 25 which.are ~ounted on a platform and raised and lowered in synchronism by a pneumatic piston ~th.e platform and piston are not s:hown~. As indicated ~y the associated arrows, ram heads 161A, 161~ and 161C are caused to rise up to caus.e groove means;160A, 160B and 160C to engage 3Q respectiye the six-point indexing ~all ~eans 154A, 154B
and 154C, lccated on second side 11-8 of th.e frame ~2, and lift factory fixture frame 82 in precise, alignment with th.e drive reference of the laser ~.e~m t~t is used to ~`~ : weld the in-process~mask 86 to mask support structure 146.
~ : 35 In effect, ~actory fixture frame 82 has two related sets of six-point indexing means: the first of the sets ~-, ~

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~ 31~7 provides for transporting frame 82 into a gross positionrelative to an operation utilizing the in-process mask, noted as being a laser mask welding and severing opera-tion. Th.e second of the sets provides for positioning 5 of th.e ~actory fixture frame 82 in the welding and severing operation such that when the in-process :Eaceplate 120 is brough.t into registry with the frame through the conjunction of ball means 138A-C on tEle faceplate with the groove means 136A-C on the frame, the :Eaceplate is so 10 located th~t th.e ~elding head can "find" the mask mounting surface 148 according to the stored mapping information o~tained in the mapping station. In addition, as in light-~ouse exposure processing, mating of the faceplate ball means. 138A-C with. the groove means 136A-C on the factory 15 fixtuxe frame assures ~.r~cise registr~ at the screen 145 witll. the center field oE apertures 104 of the clamped mask during the welding and severing operation.
With. reference again to Figure 7, ball means 154A; 154B and 154C al$o pro~ide for precise registra-20 tion of the factory fixture frame 82 wit~. a frame carrier83 r and h.ence preci~se positioning and mounting o~ the in-pxocess shado~ ma.sk in the factory ~:ixture frame ac-~: cording to the invention.
The function of th:e second of the sets o:E six-25 po.int ~ndex~ng means for assuring a~isolute accuracy isdepicted highly s:ch.ematically in Figures llA and llB.:
~am h.eads. 161P~ and 161B: Cin conjunction wit~. ram head 161C which. i.s not sh.~3wnl are indicated as having lifted factory fixture frame 82 ~rom the gross 30 pos~ition ~7h.erei.n t}~.e frame 82 was res~ing on ball means 158~, 158B. and 158C of receiving fixture 156 ljy the ~: c~njunction of the b.all means with. groove means 152A, 152B
and 152C. Th.e clamping o~ mask 86 in frame 82 is indicated :: sch ati.cally lj~.y arro~ 88A~ Faceplate 12~ is~.depicted as 35 rest.ing on car~iage 162, indicated sym~olically as being Inade of a plastlc. ~ pLastic softer than the glass of the ,, .

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~ 31~77 faceplate is preferred as a carrier as it will not scratch or otherwise abrade the polished surface of the faceplate.
As indicated by the associated arrow, carriage 162 can be raised and lowered by the pneumatic piston 163, 5 depicted in Figure llA as being in the lowered position.
Figure llB. depicts in-process faceplate 120 as having been lifted by piston 163 into exact registration ; with. factory fixture frame 82 and with the in-process ~ shado~ mask 86 contained thereinO The means of registra-:~ 10 tion of the in-process faceplate with. the factory fixture frame are indicated as comprising the conjunction of ball means 138a, 138b (:and 138C, not shbwn~ that extend from faceplate 120 with.groove means 136A, 136B, (.and 136C
; not sh.own) that extend inwardly from factory fixture frame 15 82. The mas.k-receiving surface 14.8 of shadow mask support structure 146 is indicated in Figure llB as bei.ng in inti.mate, uni~orm contact wit~. the s~adow mask 86.
Th.e mask 86 could as ~ell be in a negative interference relationship ~it~ the mask~recei.ving surface 148 masX
2Q s.upp~rt s;tructure 146.
The in-process mas:k 86, still clamped in tension : in th.e factor~ fi:xture frame 82, is welded to mask re-cei.ving surface 148 of the shadow~mask.support structure :~ 146; th.e w.eld line 164 is indicated in Figures 4 and 10.
2S Welding is: pre.~erab.ly accomplished with.the.beam of a carbon dioxide laser. T~e welding process is indicated s.chematically in Figure llB by arrow 166 whic~ represents the laser b.ea~.: Upon completion of t~e welding, th.e power of th.e beam i.s reduced an.d t~e ~rame 106 o~ un-30 perforated metal of in~process shadow mask 86 is severedat trim line lQ8r indicated ~y t~e arrow; th.e trim line 10.8 i.s ~ls.o lndicated in ~igures 4 and 10.
Upon completion of ~he severin~ operation, the in-proces.s sh~do~ ~ask., now secured to mas-k.support struc-35 ture 146, is free ~f the ~actory fixture frame 82, and theassemhly has become a vi:a~le ~aceplate. assembly complete .. ~ .

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wlth a phosphor-bearing screen 145, and ready for at-tachment to a funnel. The attachment of a faceplate as-sembly to a funnel is depicted in Figuxe 1.
The factory fixture frame 82 is reinstalled in 5 the mask tensi.ng-clamping mach1ne 96, and the remainder of the mask 86 that is st.ill clamped i.n the frame 82;
that is, the frame 106 of unperforated metal, is removed from the frame, and a new in-process mask is tensed and clamped in the frame. The cycle of f~ceplate photoscreen-1~ ing, and mask welding and severing, is th.en repeated.
~; In s.ummary, the process according to a prefer-red aspect of the invention for use in t~e manufacture of a color cathode. ray tube having a flat faceplate and a tensed foil shadow mask comprises th.e folLowing--providing a reusable, generall~ rectangular factory flxture frame having quick-release mech.anical mask-xeta~ning means;
~; temporarily and removahl~ supporting an in-pro-ces.s sh.adow mas~ i.n tension on the: frame ~ the mechanical 20 mas:k-retaining means;
pxoYidin~ on ~ first side of the frame six-point index~.ng means and, using th.e indexing means, and ~ registering th.e frame and the mask with a ph.otoexposure :~ lighthsuse h~ving complementary six-point indexing means;
provid~ng on ~ second, opposed side of the fra~e ~ix-point i.ndexing means, and registering the frame and th.e mask.~ith means for affixing th.e mask to a mask-:; supporting s.tructure on the faceplate;
affixing th.e mask to the mask-supportin~ struc-30 ture; and ~ -: ~: se.Yexing th.e com~ined mask and faceplate assembly from th~ fxa~e th.ere~.y releasing the frame for reuse.
Additionally and further in accord with a pre-ferred aspect of th.e:inventive process, third and fourth : 35 six-point indexing means are provided on the second side : 118 of factory fixture frame 82 for gross and fine - 22 - ~3~7~
registration, respectively, of the frame 82 according to the invention, and the in~process mask 86, with comple-mentary six-point indexing means on the mask welding and severing machine~ It is eesential that the material of 5 which the factory fixture frame is made provide a struc-ture th.at is reusable, rigid in construction~ and yet relatively light inw eight for easy handling. A preferred material is cast stainless steel which provides the necessary rigidity and corrosion resistance. The ligh t-10 ness of thR factory fixture frame according to the in-vention is due to its construction, in that it is cast in th.e form of thin m~ln me~bers supported by numerous gussets. Th~ factory fixture frame is made reusable by virtue of th.e fact that the frame 106 of unperforated 15 metal of the in process shadow mask is not permanently secured to th.e factory fixture frame by means such as welding, b.ut instead, by quick-release mechanical means according to the invention. Components of the six-point -.
: indexing means such ~ groove means and ~all means are 20 neces.sarily h~rdened to limit t~e effects of physical wear and the trauma of physical shock. and impact~inherent in the positioning and xetr;eving of t~.e frame ~y hand during production.

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Claims (12)

1. A reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for temporarily mounting and conveying an in-process shadow mask for processing by manufacturing machinery, said frame comprising a generally rectangular frame means having a first side and an opposed second side, at least one of said sides having at least first and second six-point indexing means azimuthally rotated with respect to each other for indexed mating with complementary six-point indexing means on said manufacturing machinery.

2. The factory fixture frame according to claim 1 wherein said first six-point indexing means on said first side also provides for registering said frame and said in-process mask with mask tensing and clamping means having complementary six-point indexing means.

3. The factory fixture frame according to claim 1 including third and fourth six-point indexing means on said second side for gross and fine registration, respectively, of said frame and said in-process mask with assembly means for affixing said mask to mask-support means extending from said faceplate, said assembly means including complementary six-point indexing means for each of said third and fourth six point indexing means of said factory fixture frame.

4. A reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for mounting an in-process shadow mask during photoexposure of an in-process faceplate in a lighthouse, said frame comprising generally rectangular frame means and quick-release mechanical mask-retaining means for temporarily and removably supporting an in-process shadow mask in tension, said frame having first six-point indexing means on a first side for registration with complementary registration-affording means on an exposure lighthouse, and second six-point indexing means on a second, opposed side for registration with complementary registration-affording means on said in-process faceplate, whereby said in-process shadow mask can be precisely registered and re-registered with said lighthouse and said in-process faceplate for the photoexposure of said in-process faceplate while retaining said in-process shadow mask in tension.

5. The factory fixture frame according to claim 4 wherein said quick-release mechanical mask-retaining means of said factory fixture frame provides for the cementless and weldless quick-retention and release of said in-process shadow mask.

6. The factory fixture frame according to claim 4 wherein said quick-release mechanical mask-retaining means of said factory fixture frame provides for the retention of said in-process mask out of the plane of said mask.

7. A reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for mounting an in-process shadow mask during photoexposure of an in-process faceplate in a lighthouse, said frame comprising generally rectangular frame means and quick-release mechanical mask-retaining means for temporarily and removably supporting an in-process shadow mask in tension out of the plane of said mask, and providing for quick cementless and weldless retention and release of said mask, said frame having first six-point indexing means on a first side for registration with complementary registration-affording means on an exposure lighthouse, and second six-point indexing means on a second side for registration with complementary registration-affording means on both said whereby said in-process mask can be precisely registered and reregistered with said lighthouse and said in-process faceplate for the photoexposure of said in-process faceplate while retaining said in-process mask in tension, and whereby said frame and said in-process mask can be registered with said mask tensing and clamping means.

8. The factory fixture frame according to claim 7 including third and fourth six-point indexing means on said second side for the gross and fine registration, respectively, of said frame and said in-process mask with assembly means for affixing said mask to mask-support means secured to said faceplate, said assembly means including complementary six-point indexing means for each of said third and fourth six-point indexing means of said factory fixture frame.

9. A reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for temporarily mounting and conveying an in-process shadow mask for processing by manufacturing machinery, said frame comprising generally rectangular frame means having six-point indexing means on a first side for indexed mating first with complementary six-point indexing means located on means for mask tensing and clamping, and subsequently with indexing means located on a lighthouse, and six-point indexing means on a second, opposed side for indexed mating with complementary six-point indexing means on an in-process faceplate.

10. A reusable factory fixture frame in use of the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask for mounting an in-process shadow mask, said frame comprising generally rectangular frame means and quick-release mechanical mask-retaining means for temporarily and removably supporting an in-process shadow mask in tension, said frame having two related sets of six-point indexing means, the first of said sets providing for transporting said frame into a gross position relative to an operation utilizing said mask, with the second of said sets providing for assuring absolute accuracy in positioning said frame during said operation utilizing said mask.

11. A process for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask, the process comprising:
providing a reusable, generally rectangular factory fixture frame having quick-release mechanical mask-retaining means;
temporarily and removably supporting an in-process shadow ask in tension on said frame by said mechanical mask-retaining means;
providing on a first side of said frame six-point indexing means and, using said indexing means, registering said frame and said mask with a photoexposure lighthouse having complementary six-point indexing means;
providing on a second, opposed side of said frame six-point indexing means, and registering said frame and said mask with means for affixing said mask to a mask-supporting structure on said faceplate; affixing said mask to said mask-supporting structure; and severing the combined mask and faceplate assembly from said frame thereby releasing said frame for reuse.

12. A process for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask, comprising:
providing a reusable, generally rectangular factory fixture frame having quick-release mechanical mask-retaining means;
temporarily and removably supporting an in-process shadow mask in tension on said frame with said mechanical mask-retaining means;
providing a faceplate having indexing means extending from the side thereof for registration with indexing means extending internally from said factory fixture frame;
providing a shadow-mask-supporting structure and securing said structure to the screen-bearing surface of said faceplate on opposed sides of the screen;
affixing said in-process shadow mask in tension to said supporting structure; and severing the combined mask-faceplate assembly from said frame thereby releasing said frame for reuse.