CA1189898A - Method of and device for determining color-purity- and convergence-correcting quantities on the screen of an in-line color-picture tube having magnetic deflection means - Google Patents
Method of and device for determining color-purity- and convergence-correcting quantities on the screen of an in-line color-picture tube having magnetic deflection meansInfo
- Publication number
- CA1189898A CA1189898A CA000400044A CA400044A CA1189898A CA 1189898 A CA1189898 A CA 1189898A CA 000400044 A CA000400044 A CA 000400044A CA 400044 A CA400044 A CA 400044A CA 1189898 A CA1189898 A CA 1189898A
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- slit
- color
- electron beams
- screen
- convergence
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/44—Factory adjustment of completed discharge tubes or lamps to comply with desired tolerances
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N17/00—Diagnosis, testing or measuring for television systems or their details
- H04N17/04—Diagnosis, testing or measuring for television systems or their details for receivers
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- General Health & Medical Sciences (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Video Image Reproduction Devices For Color Tv Systems (AREA)
- Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
- Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
Abstract
E.Kieale -2 Abstract In color-picture tubes, a maximum of three photode-tectors disposed behind the slit of a diaphragm in front of the screen center are used to determine deviations from color purity by measuring the lumi-nance distribution, and deviations from convergence by measuring the time sequence of the phosphor-stripe illuminations. By means of magnetizing cur-rents in suitable deflection means, the measured deviations are compensated for. The strengths and directions of the compensating currents determine the magnitude and direction of the correction.
With this method, the measurement of deviations for performing corresponding adjustments can be auto-mated at low cost.
With this method, the measurement of deviations for performing corresponding adjustments can be auto-mated at low cost.
Description
T}~e ~?resent invention relates -to a method o-f de~-termininq colo.r-purity- ancl collvc~rcJetlce correct:il-q c~uantl.tie.s on t.he screen of ~ i ll- 1. ine CO l.o r-p:ic tU:Y`C` tu~e wh:ich hasmcl~llcl:i.c del.1.ect:;.on mealls and to devices :Eor car:rying out this met.llod.
In-line color-picture tubes use three eoplanar elec-tron guns in -the tube neck whose beams in-te.rsec-t at a shadow mask in front of the screcn. Aftcr passincJ throu~h the s.Lits o:f` th:is shadow mask, the beallls divc-~:rqe, so that each o thc-~m hits olle o:f^ t:hc~
red, c~reell or bl.ue phospllor slri.pes, assi.qlled f:o cactl ~ow oE mar;lc slits. ~rhus, ~he ~uns and thcia~ beams can be nalllcd a~f.ter Ille colors exi-ted by them on the sereen. rrhe accuracy with wh:ich the red, green, and blue beams intersect at -the slit mask and then st.rike their assicJned phosphor stripes on the screen is not always sufficient due to manufacturinc3 variations. For subsecfuent eorreetion, means are therefore provided whieh permit adjustment on the finished tube. During that adjustment, a beam, preferably at the center of the tube, is directed so as to strike only its assigned phosphor stripe in the desired position. After this color purity adjustment, the red and blue outer beams are brought to coincidence with the center beam, which has been adjusted for green; this is called "conver~ence adjustment". This adjust-ment is performed il9~3 , .ri th ~ e a i.d o~ a ~-ri(t l~aS ter on the screen, where arZ.~ r.lale~djusti.lelZt is sho;m b-~! red or blue patterns oeing out of reg~i.ster ~`~i-th the green patterrZ. To pre-ci.',c.l.,y- Sl1 ~e:t:~imposc? the three pat; terY.Z~C~ t;o :form a whi-te t)at-tern, the re1 arl.d ~)Lue oZl-ter beams are brought to thc col:r.cc-t po~iiti.o~Z by l.le;lns of rllagne-t:lc ;Cie:Lds producect ncar ~llc e:l.ecl;:ron~ ~ sys-tem ei-l;l~e.t.~ outsl(le tn(! tu~ ec~ adJ~ irlg tilctlns, e~,~;., so--c~.ll'L(?d rilu:Lt.ipo.lo ~In.its~ o,r i)~'l (l(~)o~.;lt:in~ m~-lgrle~t;i.c ma-t,e:t.~ial :i.n tlle e:l.cctl:on- ~ln s~stem :i-t;sel:f. In l;he :Cirst case, rlu'l t i n o ter ~ ne t i c r.ings are ro-tated ~ith respec-t to G'~e CillOt'~ei`, and in the second case, a ~ermanent !lat~;rlctic rle~-terial is ?rovided ~;ith -the necessary olari-t~- ïro~. outside, either section by sec-tion or -throllt~hou-t.
rO achieve convergence by these manual adjusting mears recuires s'~ill and tal~es com?aritively long~
i~lso, the resul~ oî the adjustment depends on the adjusting device used, the subjective impression and e''?erience OI the adjuster, the picture tube to boe adjus-ted, and the adjustmZent data ol' that tube.
The object of the inven-tion is to Provide a method of deter~Zinin, the ci~ata renllired to achieve ob-je t.ive s~dausti.len-t lnd to permi-t con-tinuous re-COrCiirl'- O ~ ; le deViatiO3:1S OI the tubes produced cont'd.
Various atteml.ts to attain this ob~ect have been m~1de by usi.nc~ a ~?lura:l:ity ol` ser1sors. Dl.~-OS 27 ~ 65, for example, d~scribes a so1.ut:i.on cml~loyincJ an a1^r.ly of ser1sc)rs i.n front of thc cente:r of the screen. By means o:E eva:Luating circults, information on the positions and coincidence of the exited phosphor areas are obtained, starting Erom the sensor-array pat-terns for red, qreen, and blue. The evaluakinc3 circuitry, like the sensor array itse.1.E, is very e~penslve, particularly iE th(~ eva1.u~t.iot is to be suEficiently :East.
Anothe~r disadval1~-acJe o.E the use o:E sel1sor a.~rays :i.s that :resol.-~
ution is possil~le only down to tl1e size oE the light-sensit.ive cell, i.e., the sensor. If a glass-fiber matri~ is used, the resolution is sufficient, but the cost of the large number of sensors required is unacceptably high.
According to a first broad aspect of the invention, the method set forth in the opening paragraph of this specification is char-acterized in that deviations from the correct angles of incidence of the electron beams (color purity) are de-termined by measuring the luminance distribu-tion produced by the three electron beams on the associated phosphor stripe behind a mask sli-t or a row of mask slits, and ~hat deviations from coincidence (convergence) are determined by measuring the deviatlon of the -three electron beams from their synchronous passaqe through the same mask sli-t or the same row of slits as the time difference between the illum-inations of the associated phosphor stripes, the instant of the passage of the center beam being the reference value for the syn-chronization of the outer beams.
g~
Accordinc~ to another aspect, a device for carryin~ out the metllod i.s characte~ ed in that., to dctermirlc~ the necessary correctin~
C~Uall~..iti.CS, a ';] it e~tend.irl~ pe~rpetldicu:Lar to t.he pl.ane of move-men-t o:E the elc-~ctron beams ancl havlncl a width at l.east equal to the spacing o:E the rows of mask slits measured in the directlon of movemellt of -the electron beams is provided preferably at the center of the screen, beh;nd wh;.ch s].i.t are disposed one or mo:re phot-osensors, and that, to de:Elect the e~ectron beams, cir-cuits inclependellt of the deflectiorl clrcuit are prov~ ed which, for color-purity correction, pass cu~rent throug}l ~n c~ual.ly poled two-coil. group whose axis is normal. to the plane in which the electron beams are ~enerated, and, for convergence correc-tion, pass cur.rent through either of two oppositely poled two-coil groups whose axes are inclined to -the electron-beam plane at 45 and 0 or 90, the two-coil groups consisting of elonga-te, rectangular coils fitted within one another in the circumferential direction above the beam-generating system outside the tube neck.
To achieve fast evaluation and sufficient resolution with only three illumination sensors, one for red, one for green, and one for blue, deviations from the correct anqles of incidenee of -the electron beams (color-purity) are determined by measuring the luminance distribution, -3a-. 4 and -to determlne devlcl-tions :~rom the convergence condit;lon, -the -time sequence of the passages of the be~ms through the sc~me mask slit is evaluated. This is possible because the deflection and the signals ~a.ted into -the grid of the in-line system act on a~Ll -three beams simult~neouslyr 'rhe center b~,~n is used as the rcference beam for the synchroni.2,.ltion o:f -the outer beams~
The inven~ion star-ts :t`rom -the fact that ~ spat:ial convergence of the beams moved by -the deflection fields i.s au-tomatically connected with the -time coincidence of the beams, To de+ermine the color-purity-correcting quantity for the center beam or the outer beams, a slit extending perpendicular to the plane of movement of the electron beams and having a width at least equal to the slit spacing of the shadow mask is pro-vided in fron-t of the screen at the certer thereof.
The luminance so isolated is picked up by three color-sensitive devices (photocells, photodiodes, photo multiplier tubes, etc t ) ~ This permits -the brightness of each color to be determined quantita-tively in real time.
By adjusting currents in an equally poled two-coil group ~hose effective axis is normal to the electron-gun system and which is disposed above the neck-to-cone transition zone of the tube or above the elec-cont'd~
E.~i:ienl~ -2 t:~'OII~ sy~.tem, tllc des:i:re(l :l~umi.nance v~r:i~l~;;.or-is adjusted Lo~; tlle cellter be~-~, WhiC.il .iS theIl c~vailable ~s a reference :Eo:r the ~ynchroni~ation of the outer be~ms.
Convergenc~ must be ad~usted two-dimensionally in tlle hori.~;o.n-tal and vertica:l. di.rections with re5pèct to the 3creen, l.e., in the x- .~nd y-directions, t,llcre fore~ the a(l.;justmen-t is c~ommon.~y pe~ormed w:il;h the ~ic( of rast;ers, ~ccor~:in~ t,o -~h~ in~en-tion, hotrever, -the convergence co.rrectirlg ~arl~:ltg ls cle-terlllined by means o~` a narrow slit e~-tend.ing perpendicular to the plane of deflection.
~ith suitable wiring i-t is possible to use the same sli-t fo~ de-termining both the color~purity-cor-recting quantity and the convergence-correcting quantity, with the slit having to be ro-tated by 90 for the y-correction~
'rhe correction for the bWO outer beams relatl~e to the reference beam at the center can be determined by mounting two oppositely poled two-coil groups of preferably rectangular shape on the outside of the tube neck above the electron-O~un system7 one parallel or perpendicular, and -the other a-t about 45~ to the electron-gun sys-tem, 'rhe adjustment of the posi-tions o~ the outer beams for obtaining the correcting quan-tity as -the ~alue of the deflection current necessary for correction cont'd~
C.~tl .llso ~ r~orl!lod t;it~l t~-L~ id o~ ul-tL-co:il grou~?s consis-ting of t;llree or more pairs of coiLs~
~hi,s ofLers -the adv~tage that -the outer beams can also be influenced in the same direc-tion.
~hile in thls method the number of co:lor-sensitive sensors behind -the dlaphrngm apertu-re equ~ls the number (f coLors -to ~e observe(l, a f`urther ~mbodi~
ueIIt ol` t,he invention IISeS only one netl-~ra'l ~lensor if the informat; iOll on the excited color ls tr~l~rls-fer-red (~lrectly -to an electronic circui-t.
The locations of -the sensors and the diaphragm slit depend on -the ma~imum deviation and the mask structure. According to the invention, -the require-ments placed on posi-tion accuracy are mitigated in both relations by using an additional field w~ich is normal to the direction of deflec-tion and has a high frequency as compared -to that of the deflection field. ~rom the straight-line luminous paths of the beams, sufficiently wide bands are formed, so that the sensor~ i.e., the slit dia-phragm, can be used in the same position for several rows of mask slits~
rrhe method and the device according -to the inven-tion ~ill now be e~plained with reference to the accompanying drawing3~
cont'dO
Fi.g, 1 shows schematica:Lly a sensor l behind a s-1it 2 in a diaphragm 3 placed in .f*~ont of a screen 4 coa-ted wi-th a phosphor layer 5 'rhe phosphor st,r.ipes 6 of the phosphor ,I.ayer 5 are st~lclc by th-.ree electro~ 'be~ms 7. Opposite each slit 8 :in the shadow ma~lc 9 ls one of -the phosphor-stripe tr:Lo3 Qon-sls~irlg of one recl stripe, one gree.ll stript??
and one blue st;r.ipeS, I~S a result o:~ I,heir difEerent angles of incidence 10 (color~
selectlon angles), the red~ g-reen and blue beams will only s-trike their assîgned phos-phor stripes if correctly adjusted.
Fig. 2 shows three phosphor areas about 3 to 9 cm in length and about 3 to 9 mm in width which are located at the center of a screen and are not yet in coincidence~ After the three red, green9 and blue phosphor areas 11 have been brought to coincidence in -the x-direc-tlon, the same is done in the y-direc-tion ~12) until the entire border of the stripe appears white.
Fig, 3 shows a two-coil group 13 above the ~eck of a picture tube 14~ an electron-gun sys-tem 15~ and the deflection unit 16 associated with the tube. lhe coils are posi-tioned so that the ou-ter beams will be deflected in the vertical direction (y-direction) i:E the cont' d o g~
iorlle -2 coiLs arc ol?l;)ositely poLed~
Fig~ ~ 3ho~s the po~ition of the two-~o~l g~oup 13 ~lative to that o~ the electron~
g~un systctn. ~f ti~e coils are oppositely poled~ the curxent will de1ect the outer beams in the ver-tic.ll ~lirectiorl (y~dlrection)~
l~`;g. 5 SllOws t}le ~wo-coiL grollp turned t;hrougl~ abou-t ~l5~, so that the outer be~ms trill be de-flec-ted in the horizon-tal directioIl (x~direc--tlon) when the curren-ts flowing in the two coils have opposite directions.
~ig. 6 shows the relationship be-tween coil position, coil polarity and direction of deflection in a plane perpendicular to the elec-tron beams 17. The resulting field dis-tribution is il-lustrated by the lines 180 ~he arrow 19 in-dicates the direction of change of the beam position.
~ig~ 7 shows a multi-pole coil unit with three two-coil groups 13 fitted within one another in the circumferen-tial direction. ~he coil pair having vertical axes can be used to determine the color~purity ct~rr~ction, in which case the polari--ties of the two coils a~?e chosen so -that the magnetic fields have the same directionsO
~he coil pairs with horizontal axes and with e~es inclined a-t 45 serve to determine the cont 7 d~
8~
E.Kienle -2 convergence-correcting quantities for -the direction and the x~direc-tion, respec-tive-ly. If the current directions are reversicle in all coils, the coil pair having horizontal axes can be omitted.
~irst, color purity is adjusted for the center beam by adjusting the currents in an equally poled two-coil group 13 as sho~rn in ~ig. 3b9 i~e., the color-selection angle is corrected until the desired po-sition of -the elec-tron beam on the phosphor stripe, e,g., the central position7 is reached7 so that the sensor provides the corresponding variation of intensit~ with time.
This is followed by the convergence adjustment~ The beams must strike not only their assigned phosphor stripes but also the phosphor stripes of -the same phosphor-stripe group, i.e., they must pass through -the same mask slits 8 at the same time (see also ~ig. 1). This is again adjusted by means of the currents in the coils, and the magnitudes and direc tions of -the currents are the magnitudes and direc-tions of the deviations to be compensated for. The cri-terion for the spatial convergence of all three beams at an opening in -the shadow mask is time coin~
cidence. According to the in~e-ntion9 the difference in time of arrival bet~reen the two outer beams (red and blue) and the center beam (green) a-t the aper-ture 2 of the diaphragm 3 is observed, To this end~
cont' a .
, T`~ l L ~? --~
;llc~ <~o~ rL~o~ r~ nsors ~ of tl~ tl~OJ~ r~ r~ clrr~ ;ed o~l~
abotr~ e other arld alre e~ci~ sen~i~ive to one color are e~aluated for the vie~Jer. S~nchronism of all beams ~l~ans congruence o~ the phosphor areas 11 or 12 (I~ ') end is t;~lUS e~llival~nt to convergence, ~JI~ tl.o adjustecl by subjective obel~se~vation of t~c ras-ter. ~kl objectlve measllrement oC the cor-xcction~coil curren~s ir~ t~le two- or mllltl-coiL
g~rouos is not; l~oss;b~le ~`~lth a s,r~lall amount of com-ponents ~par-l;;.cularl~y sensors)~ an(l tile mea3ure--ment can be -performed ~ulckly ~nd with high ~c-curac,~, ~'or -l,lle -time meclsurement, all -t;hree bec~ns are tuLned on simultaneously (if three color-sensitive sensors are used) or cyclically (if only one neutral sensor is presen-t, and the electronic is informed otherwise tthich beam is on). The time posi-tion of the sensor signals is adjusted first for the x-direction by means of oppositely poled coils as shown in Fig. 6c and -then in the y-direction ~y means of oppositely poled coils as sho~,n in Fig. 6a.
The sensors can be conven~tional photodiodes, photo-cells, photomultiplier tubes~ etc. During the whole mecasuring process, the beams are additionally de-flected transversel~; -to the main direction of de-1ection at a high Ire uency, so that not only lines but the phosphor areas 11 and 12 are covered, ~rhich facilitates the positioning of -the sensors~
contldo
In-line color-picture tubes use three eoplanar elec-tron guns in -the tube neck whose beams in-te.rsec-t at a shadow mask in front of the screcn. Aftcr passincJ throu~h the s.Lits o:f` th:is shadow mask, the beallls divc-~:rqe, so that each o thc-~m hits olle o:f^ t:hc~
red, c~reell or bl.ue phospllor slri.pes, assi.qlled f:o cactl ~ow oE mar;lc slits. ~rhus, ~he ~uns and thcia~ beams can be nalllcd a~f.ter Ille colors exi-ted by them on the sereen. rrhe accuracy with wh:ich the red, green, and blue beams intersect at -the slit mask and then st.rike their assicJned phosphor stripes on the screen is not always sufficient due to manufacturinc3 variations. For subsecfuent eorreetion, means are therefore provided whieh permit adjustment on the finished tube. During that adjustment, a beam, preferably at the center of the tube, is directed so as to strike only its assigned phosphor stripe in the desired position. After this color purity adjustment, the red and blue outer beams are brought to coincidence with the center beam, which has been adjusted for green; this is called "conver~ence adjustment". This adjust-ment is performed il9~3 , .ri th ~ e a i.d o~ a ~-ri(t l~aS ter on the screen, where arZ.~ r.lale~djusti.lelZt is sho;m b-~! red or blue patterns oeing out of reg~i.ster ~`~i-th the green patterrZ. To pre-ci.',c.l.,y- Sl1 ~e:t:~imposc? the three pat; terY.Z~C~ t;o :form a whi-te t)at-tern, the re1 arl.d ~)Lue oZl-ter beams are brought to thc col:r.cc-t po~iiti.o~Z by l.le;lns of rllagne-t:lc ;Cie:Lds producect ncar ~llc e:l.ecl;:ron~ ~ sys-tem ei-l;l~e.t.~ outsl(le tn(! tu~ ec~ adJ~ irlg tilctlns, e~,~;., so--c~.ll'L(?d rilu:Lt.ipo.lo ~In.its~ o,r i)~'l (l(~)o~.;lt:in~ m~-lgrle~t;i.c ma-t,e:t.~ial :i.n tlle e:l.cctl:on- ~ln s~stem :i-t;sel:f. In l;he :Cirst case, rlu'l t i n o ter ~ ne t i c r.ings are ro-tated ~ith respec-t to G'~e CillOt'~ei`, and in the second case, a ~ermanent !lat~;rlctic rle~-terial is ?rovided ~;ith -the necessary olari-t~- ïro~. outside, either section by sec-tion or -throllt~hou-t.
rO achieve convergence by these manual adjusting mears recuires s'~ill and tal~es com?aritively long~
i~lso, the resul~ oî the adjustment depends on the adjusting device used, the subjective impression and e''?erience OI the adjuster, the picture tube to boe adjus-ted, and the adjustmZent data ol' that tube.
The object of the inven-tion is to Provide a method of deter~Zinin, the ci~ata renllired to achieve ob-je t.ive s~dausti.len-t lnd to permi-t con-tinuous re-COrCiirl'- O ~ ; le deViatiO3:1S OI the tubes produced cont'd.
Various atteml.ts to attain this ob~ect have been m~1de by usi.nc~ a ~?lura:l:ity ol` ser1sors. Dl.~-OS 27 ~ 65, for example, d~scribes a so1.ut:i.on cml~loyincJ an a1^r.ly of ser1sc)rs i.n front of thc cente:r of the screen. By means o:E eva:Luating circults, information on the positions and coincidence of the exited phosphor areas are obtained, starting Erom the sensor-array pat-terns for red, qreen, and blue. The evaluakinc3 circuitry, like the sensor array itse.1.E, is very e~penslve, particularly iE th(~ eva1.u~t.iot is to be suEficiently :East.
Anothe~r disadval1~-acJe o.E the use o:E sel1sor a.~rays :i.s that :resol.-~
ution is possil~le only down to tl1e size oE the light-sensit.ive cell, i.e., the sensor. If a glass-fiber matri~ is used, the resolution is sufficient, but the cost of the large number of sensors required is unacceptably high.
According to a first broad aspect of the invention, the method set forth in the opening paragraph of this specification is char-acterized in that deviations from the correct angles of incidence of the electron beams (color purity) are de-termined by measuring the luminance distribu-tion produced by the three electron beams on the associated phosphor stripe behind a mask sli-t or a row of mask slits, and ~hat deviations from coincidence (convergence) are determined by measuring the deviatlon of the -three electron beams from their synchronous passaqe through the same mask sli-t or the same row of slits as the time difference between the illum-inations of the associated phosphor stripes, the instant of the passage of the center beam being the reference value for the syn-chronization of the outer beams.
g~
Accordinc~ to another aspect, a device for carryin~ out the metllod i.s characte~ ed in that., to dctermirlc~ the necessary correctin~
C~Uall~..iti.CS, a ';] it e~tend.irl~ pe~rpetldicu:Lar to t.he pl.ane of move-men-t o:E the elc-~ctron beams ancl havlncl a width at l.east equal to the spacing o:E the rows of mask slits measured in the directlon of movemellt of -the electron beams is provided preferably at the center of the screen, beh;nd wh;.ch s].i.t are disposed one or mo:re phot-osensors, and that, to de:Elect the e~ectron beams, cir-cuits inclependellt of the deflectiorl clrcuit are prov~ ed which, for color-purity correction, pass cu~rent throug}l ~n c~ual.ly poled two-coil. group whose axis is normal. to the plane in which the electron beams are ~enerated, and, for convergence correc-tion, pass cur.rent through either of two oppositely poled two-coil groups whose axes are inclined to -the electron-beam plane at 45 and 0 or 90, the two-coil groups consisting of elonga-te, rectangular coils fitted within one another in the circumferential direction above the beam-generating system outside the tube neck.
To achieve fast evaluation and sufficient resolution with only three illumination sensors, one for red, one for green, and one for blue, deviations from the correct anqles of incidenee of -the electron beams (color-purity) are determined by measuring the luminance distribution, -3a-. 4 and -to determlne devlcl-tions :~rom the convergence condit;lon, -the -time sequence of the passages of the be~ms through the sc~me mask slit is evaluated. This is possible because the deflection and the signals ~a.ted into -the grid of the in-line system act on a~Ll -three beams simult~neouslyr 'rhe center b~,~n is used as the rcference beam for the synchroni.2,.ltion o:f -the outer beams~
The inven~ion star-ts :t`rom -the fact that ~ spat:ial convergence of the beams moved by -the deflection fields i.s au-tomatically connected with the -time coincidence of the beams, To de+ermine the color-purity-correcting quantity for the center beam or the outer beams, a slit extending perpendicular to the plane of movement of the electron beams and having a width at least equal to the slit spacing of the shadow mask is pro-vided in fron-t of the screen at the certer thereof.
The luminance so isolated is picked up by three color-sensitive devices (photocells, photodiodes, photo multiplier tubes, etc t ) ~ This permits -the brightness of each color to be determined quantita-tively in real time.
By adjusting currents in an equally poled two-coil group ~hose effective axis is normal to the electron-gun system and which is disposed above the neck-to-cone transition zone of the tube or above the elec-cont'd~
E.~i:ienl~ -2 t:~'OII~ sy~.tem, tllc des:i:re(l :l~umi.nance v~r:i~l~;;.or-is adjusted Lo~; tlle cellter be~-~, WhiC.il .iS theIl c~vailable ~s a reference :Eo:r the ~ynchroni~ation of the outer be~ms.
Convergenc~ must be ad~usted two-dimensionally in tlle hori.~;o.n-tal and vertica:l. di.rections with re5pèct to the 3creen, l.e., in the x- .~nd y-directions, t,llcre fore~ the a(l.;justmen-t is c~ommon.~y pe~ormed w:il;h the ~ic( of rast;ers, ~ccor~:in~ t,o -~h~ in~en-tion, hotrever, -the convergence co.rrectirlg ~arl~:ltg ls cle-terlllined by means o~` a narrow slit e~-tend.ing perpendicular to the plane of deflection.
~ith suitable wiring i-t is possible to use the same sli-t fo~ de-termining both the color~purity-cor-recting quantity and the convergence-correcting quantity, with the slit having to be ro-tated by 90 for the y-correction~
'rhe correction for the bWO outer beams relatl~e to the reference beam at the center can be determined by mounting two oppositely poled two-coil groups of preferably rectangular shape on the outside of the tube neck above the electron-O~un system7 one parallel or perpendicular, and -the other a-t about 45~ to the electron-gun sys-tem, 'rhe adjustment of the posi-tions o~ the outer beams for obtaining the correcting quan-tity as -the ~alue of the deflection current necessary for correction cont'd~
C.~tl .llso ~ r~orl!lod t;it~l t~-L~ id o~ ul-tL-co:il grou~?s consis-ting of t;llree or more pairs of coiLs~
~hi,s ofLers -the adv~tage that -the outer beams can also be influenced in the same direc-tion.
~hile in thls method the number of co:lor-sensitive sensors behind -the dlaphrngm apertu-re equ~ls the number (f coLors -to ~e observe(l, a f`urther ~mbodi~
ueIIt ol` t,he invention IISeS only one netl-~ra'l ~lensor if the informat; iOll on the excited color ls tr~l~rls-fer-red (~lrectly -to an electronic circui-t.
The locations of -the sensors and the diaphragm slit depend on -the ma~imum deviation and the mask structure. According to the invention, -the require-ments placed on posi-tion accuracy are mitigated in both relations by using an additional field w~ich is normal to the direction of deflec-tion and has a high frequency as compared -to that of the deflection field. ~rom the straight-line luminous paths of the beams, sufficiently wide bands are formed, so that the sensor~ i.e., the slit dia-phragm, can be used in the same position for several rows of mask slits~
rrhe method and the device according -to the inven-tion ~ill now be e~plained with reference to the accompanying drawing3~
cont'dO
Fi.g, 1 shows schematica:Lly a sensor l behind a s-1it 2 in a diaphragm 3 placed in .f*~ont of a screen 4 coa-ted wi-th a phosphor layer 5 'rhe phosphor st,r.ipes 6 of the phosphor ,I.ayer 5 are st~lclc by th-.ree electro~ 'be~ms 7. Opposite each slit 8 :in the shadow ma~lc 9 ls one of -the phosphor-stripe tr:Lo3 Qon-sls~irlg of one recl stripe, one gree.ll stript??
and one blue st;r.ipeS, I~S a result o:~ I,heir difEerent angles of incidence 10 (color~
selectlon angles), the red~ g-reen and blue beams will only s-trike their assîgned phos-phor stripes if correctly adjusted.
Fig. 2 shows three phosphor areas about 3 to 9 cm in length and about 3 to 9 mm in width which are located at the center of a screen and are not yet in coincidence~ After the three red, green9 and blue phosphor areas 11 have been brought to coincidence in -the x-direc-tlon, the same is done in the y-direc-tion ~12) until the entire border of the stripe appears white.
Fig, 3 shows a two-coil group 13 above the ~eck of a picture tube 14~ an electron-gun sys-tem 15~ and the deflection unit 16 associated with the tube. lhe coils are posi-tioned so that the ou-ter beams will be deflected in the vertical direction (y-direction) i:E the cont' d o g~
iorlle -2 coiLs arc ol?l;)ositely poLed~
Fig~ ~ 3ho~s the po~ition of the two-~o~l g~oup 13 ~lative to that o~ the electron~
g~un systctn. ~f ti~e coils are oppositely poled~ the curxent will de1ect the outer beams in the ver-tic.ll ~lirectiorl (y~dlrection)~
l~`;g. 5 SllOws t}le ~wo-coiL grollp turned t;hrougl~ abou-t ~l5~, so that the outer be~ms trill be de-flec-ted in the horizon-tal directioIl (x~direc--tlon) when the curren-ts flowing in the two coils have opposite directions.
~ig. 6 shows the relationship be-tween coil position, coil polarity and direction of deflection in a plane perpendicular to the elec-tron beams 17. The resulting field dis-tribution is il-lustrated by the lines 180 ~he arrow 19 in-dicates the direction of change of the beam position.
~ig~ 7 shows a multi-pole coil unit with three two-coil groups 13 fitted within one another in the circumferen-tial direction. ~he coil pair having vertical axes can be used to determine the color~purity ct~rr~ction, in which case the polari--ties of the two coils a~?e chosen so -that the magnetic fields have the same directionsO
~he coil pairs with horizontal axes and with e~es inclined a-t 45 serve to determine the cont 7 d~
8~
E.Kienle -2 convergence-correcting quantities for -the direction and the x~direc-tion, respec-tive-ly. If the current directions are reversicle in all coils, the coil pair having horizontal axes can be omitted.
~irst, color purity is adjusted for the center beam by adjusting the currents in an equally poled two-coil group 13 as sho~rn in ~ig. 3b9 i~e., the color-selection angle is corrected until the desired po-sition of -the elec-tron beam on the phosphor stripe, e,g., the central position7 is reached7 so that the sensor provides the corresponding variation of intensit~ with time.
This is followed by the convergence adjustment~ The beams must strike not only their assigned phosphor stripes but also the phosphor stripes of -the same phosphor-stripe group, i.e., they must pass through -the same mask slits 8 at the same time (see also ~ig. 1). This is again adjusted by means of the currents in the coils, and the magnitudes and direc tions of -the currents are the magnitudes and direc-tions of the deviations to be compensated for. The cri-terion for the spatial convergence of all three beams at an opening in -the shadow mask is time coin~
cidence. According to the in~e-ntion9 the difference in time of arrival bet~reen the two outer beams (red and blue) and the center beam (green) a-t the aper-ture 2 of the diaphragm 3 is observed, To this end~
cont' a .
, T`~ l L ~? --~
;llc~ <~o~ rL~o~ r~ nsors ~ of tl~ tl~OJ~ r~ r~ clrr~ ;ed o~l~
abotr~ e other arld alre e~ci~ sen~i~ive to one color are e~aluated for the vie~Jer. S~nchronism of all beams ~l~ans congruence o~ the phosphor areas 11 or 12 (I~ ') end is t;~lUS e~llival~nt to convergence, ~JI~ tl.o adjustecl by subjective obel~se~vation of t~c ras-ter. ~kl objectlve measllrement oC the cor-xcction~coil curren~s ir~ t~le two- or mllltl-coiL
g~rouos is not; l~oss;b~le ~`~lth a s,r~lall amount of com-ponents ~par-l;;.cularl~y sensors)~ an(l tile mea3ure--ment can be -performed ~ulckly ~nd with high ~c-curac,~, ~'or -l,lle -time meclsurement, all -t;hree bec~ns are tuLned on simultaneously (if three color-sensitive sensors are used) or cyclically (if only one neutral sensor is presen-t, and the electronic is informed otherwise tthich beam is on). The time posi-tion of the sensor signals is adjusted first for the x-direction by means of oppositely poled coils as shown in Fig. 6c and -then in the y-direction ~y means of oppositely poled coils as sho~,n in Fig. 6a.
The sensors can be conven~tional photodiodes, photo-cells, photomultiplier tubes~ etc. During the whole mecasuring process, the beams are additionally de-flected transversel~; -to the main direction of de-1ection at a high Ire uency, so that not only lines but the phosphor areas 11 and 12 are covered, ~rhich facilitates the positioning of -the sensors~
contldo
Claims (10)
1. Method of determining color-purity- and convergence-correcting quantities on the screen of an in-line color-picture tube comprising magnetic deflection means, c h a r a c t e r i z e d i n that deviations from the correct angles of incidence of the electron beams (color purity) are determined by measuring the luminance distribution produced by the three electron beams on the associated phosphor stripe behind a mask slit or a row of mask slits, and that deviations from coincidence (convergence) are determined by measuring the deviation of the three electron beams from their synchronous passage through the same mask slit or the same row of slits as the time difference between the illumi-nations of the associated phosphor stripes, the in-stant of the passage of the center beam being the ref-erence value for the synchronization of the outer beams.
cont'd.
E.Kieale -2
cont'd.
E.Kieale -2
2. A method as claimed in claim 1, c h a r a c t e r i z e d i n that deviations from the correct luminance distribution and the synchronous illumination are compensated for by magnetically deflecting the electron beams, and that the current values necessary therefor in the deflection coils are the correcting quantities.
3. Device for carrying out the method claimed in claim 1, c h a r a c t e r i z e d i n that, to de-termine the necessary correcting quantities, a slit extending perpendicular to the plane of move-ment of the electron beams and having a width at least equal to the spacing of the rows of mask slits measured in the direction of movement of the electron beams is provided preferably at the center of the screen, behind which slit are disposed one or more photosensors, and that, to deflect the electron beams, circuits independent of the deflection circuit are provided which, for color-purity correction, pass current through an equally poled two-coil group whose axis is normal to the plane in which the electron beams are generated, and, for convergence correction, pass current through either of two oppositely poled two-coil groups whose axes are inclined to the electron-beam plane at 45° and 0° or 90°, the two-coil groups consisting of elongate, rectangular cont'd.
coils fitted within one another in the circumferential direction above the beam-generating system outside the tube neck.
coils fitted within one another in the circumferential direction above the beam-generating system outside the tube neck.
4. A device as claimed in claim 3, characterized in that color-sensitive sensors are located behind the slit and permanently connected with the slit diaphragm disposed on the outside, prefer-ably at the center, of the screen.
5. A device as claimed in claim 3, characterized in that one neutral sensor is located behind the slit.
6. A device as claimed in claim 3, characterized in that, in addition, one or more deflection coils are provided which pro-duce a field perpendicular to the respective existing main deflec-ting field, and that a generator supplies these coils with a current whose frequency is a multiple of main sweep frequency.
7. A device for carrying out the method claimed in claim 2 characterized in that, to determine the necessary correcting quantities, a slit extending perpendicular to the plane of move-ment of the electron beams and having a width at least equal to the spacing of the rows of mask slits measured in the direction of movement of the electron beams is provided preferably at the center of the screen, behind which slit are disposed one or more photosensors, and that, to deflect the electron beams, circuits independent of the deflection circuit are provided which, for color-purity correction, pass current through an equally poled two-coil group whose axis is normal to the plane in which the electron beams are generated, and, for convergence correction, pass current through either of two oppositely poled two-coil groups whose axes are inclined to the electron-beam plane at 45° and 0° or 90°, the two-coil groups consisting of elongated, rectan-gular coils fitted within one another in the circumferential direction above the beam-generating system outside the tube neck.
8. A device as claimed in claim 7, characterized in that color-sensitive sensors are located behind the slit and permanent-ly connected with the slit diaphragm disposed on the outside, preferably at the center, of the screen.
9. A device as claimed in claim 7, characterized in that one neutral sensor is located behind the slit.
10. A device as claimed in claim 7, characterized in that, in addition, one or more deflection coils are provided which pro-duce a field perpendicular to the respective existing main deflec-ting field, and that a generator supplies these coils with a cur-rent whose frequency is a multiple of main sweep frequency.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19813113454 DE3113454A1 (en) | 1981-04-03 | 1981-04-03 | METHOD AND DEVICE FOR DETERMINING THE COLOR UNIT AND THE CONVERGENCE CORRECTION SIZE ON A COLOR TELEVISION SCREEN OF IN-LINE TYPE WITH MAGNETIC DEFLECTING AGENTS |
| DEP3113454.8 | 1981-04-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189898A true CA1189898A (en) | 1985-07-02 |
Family
ID=6129232
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400044A Expired CA1189898A (en) | 1981-04-03 | 1982-03-31 | Method of and device for determining color-purity- and convergence-correcting quantities on the screen of an in-line color-picture tube having magnetic deflection means |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0062281B1 (en) |
| JP (1) | JPS57188180A (en) |
| CA (1) | CA1189898A (en) |
| DE (2) | DE3113454A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3206913A1 (en) * | 1982-02-26 | 1983-09-22 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | MEASURING HEAD FOR DETECTING COLOR PURITY AND CONVERGENCE IN A COLOR TUBE |
| FR2545264B1 (en) * | 1983-04-26 | 1985-12-13 | Videocolor Sa | METHOD AND APPARATUS FOR ADJUSTING STATIC CONVERGENCE AND PURITY OF COLOR TELEVISION TUBES |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1220900A (en) * | 1969-08-05 | 1971-01-27 | Mullard Ltd | Measuring the beam landing characteristic of a shadow-mask cathode-ray tube |
| JPS493203A (en) * | 1972-04-24 | 1974-01-12 | ||
| JPS5036023A (en) * | 1973-08-03 | 1975-04-04 | ||
| JPS5046443A (en) * | 1973-08-30 | 1975-04-25 | ||
| US4211960A (en) * | 1976-03-19 | 1980-07-08 | U.S. Philips Corporation | Method of manufacturing a static convergence unit, and a color display tube comprising a convergence unit manufactured according to the method |
| JPS5391521A (en) * | 1977-01-24 | 1978-08-11 | Hitachi Ltd | Detector for convergence chromatic aberration |
-
1981
- 1981-04-03 DE DE19813113454 patent/DE3113454A1/en not_active Withdrawn
-
1982
- 1982-03-30 DE DE8282102662T patent/DE3261424D1/en not_active Expired
- 1982-03-30 EP EP82102662A patent/EP0062281B1/en not_active Expired
- 1982-03-31 CA CA000400044A patent/CA1189898A/en not_active Expired
- 1982-04-02 JP JP57054005A patent/JPS57188180A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57188180A (en) | 1982-11-19 |
| EP0062281A1 (en) | 1982-10-13 |
| EP0062281B1 (en) | 1984-12-05 |
| DE3113454A1 (en) | 1982-10-21 |
| DE3261424D1 (en) | 1985-01-17 |
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