Note: Descriptions are shown in the official language in which they were submitted.
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
--1--
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~
-- 5 --
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~
3898
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 .
- 10 -
, 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
