DE1639464B2 - CATHODE RAY TUBE - Google Patents

Description

bundle so in the field of the focusing lens on its axis lies in the fact that only an area of the lens field close to the axis is used.

Because only a part of the lens field close to the axis is used, - as is known - the spherical aberrations and coma errors are significantly reduced (book "Technische Elektronik" by M. K η ο 11 and J. E i c h m e i e r, 2nd volume, Berlin 1966, pp. 238/239 and 242). This realization was made so far, however, taken into account that the origin of the electron beams, so the source point on the electron gun, as possible on the Axis of the focusing lens put.

A focusing lens is expediently used which has several electrodes which are applied to different electrical voltages and which produce a focusing of the electron lens field.

When the _o ssystemen of the Strahlerzeugun beam generated are broadcast substantially narallel each other so, an auxiliary lens disposed between the imaging systems and the focusing lens, which causes a cutting of the central rays of the bundle on the axis of the focusing lens. The auxiliary lens can be designed, for example, in such a way that it has a plurality of electrodes or grids applied to different electrical voltages.

Another expedient development of the invention Jarin can exist that the beam generating systems are arranged on a carrier so that a Cutting the central rays of the beam is brought about on the axis of the focusing lens.

If the bundles of rays are to impinge on a common point on the screen, then between the focusing lens and the screen, a deflection device may be provided, which those bundles of rays, which emerge from the focusing lens in directions diverging from the optical axis of the same, distracts so that the desired effect occurs. When the screen through an imminescent screen is formed and a shadow mask is placed in front of it, so all the beam bundles can be with the help of the focusing lens are focused on the screen, the deflection device? all beam bundles to a common Deflect point on shadow mask

If three beam generating systems are used to generate one electron beam each, so the one beam generating system in the optical axis of the focusing lens can use the other two Beam generating systems on both sides of the first at the same distance from the same on one by the the straight line passing through the optical axis may be arranged such that only those of these other two Beam generating systems emanating beam bundles the focusing lens on diverging from the lens axis Leave lanes.

The second grid behind the cathodes can be in the form of a simple disk containing openings be formed, behind which the focusing lens forming electrode ^ successively with tubular Shape and different electrical potentials are arranged, with the disc at its circumferential rim to form the auxiliary lens with a cylindrical one facing the focusing lens Side wall is connected, which is opposite to the electrical potential of the next electrode has different electrical potential.

A. exemplary embodiments of the invention are described with reference to the drawings. In the drawings shows

F i g. 1 is the optical equivalent of a color image Ka provided with three beam generating systems known type of ray tube,

F i g. 2 and 3 the optical equivalent of a tube, which in the already known way with only one A beam generating system is provided for generating several electron beams,

ίο F i g. Figure 4 is the optical equivalent of another embodiment of a known tube with only one Beam generation system for generating several electron beams, F i g. 5 the optical equivalent of a cathode

beam tube with a first embodiment of the beam generating system,

F i g. 6 one of the F i g. 5 corresponding illustration with a second embodiment of the beam generation system,

F i g. 7 and 8 the optical equivalent of embodiments the cathode ray tube according to the invention,

F i g. 9 shows a longitudinal section through one with the optical equivalent according to FIG. 5 provided cathode ray tube,

F i g. IG is an end view of Fig. 9,
Fig. U is an enlarged view of details of a first and second grating of the in the embodiment of FIG. 9 used beam generation system,

F i g. 12 a section along the line II-U of the Fig. 11,

F i g. 13 shows an axial section through a chromatron-type Color picture tube,

Fig. 4Α and 14B a side and an end view a magnetic deflector which is used to converge the electron beams in a Cathode ray tube according to the invention can be used.

For a better understanding of the invention, FIGS. 1 to 4 first the design principles and features of known cathode ray tubes with three beam generating systems or one beam generating system for generating three electron beams each described.

Gf, according to F i g. 1, three mutually independent beam generating systems A _x , A., and A ₃ with three independent beam generating sources K _x , K ₂ and K _z for emitting one electron beam B _x , B., and B. ₆ each are arranged. The three electron beam bundles are focused on a phosphorescent screen S with the aid of separate lens systems L ₁ , L ₂ and ^ ₃ . With such an arrangement, the three independent beam generation

5 ::, systems A _x , A ₂ and A ₃ , which must be accommodated in the neck portion of the tubular piston, take up a relatively large amount of space and limit the extent to which the diameter of the neck portion could be reduced. Difficulties with regard to the precise alignment required for converging the electron beams B _x , B ₁ and Β _λ on the screen S also arise with three Stranlergenerating systems.

In the training according to FIG. 2, a beam generation system A of known type is used with three equivalent beam generation sources K ₁ , K ₂ and K ₃ , which are arranged at mutual distances d , and three electron beam bundles B _x , B ₁ and B ₃

5 6

radiate parallel to each other. These electrons are to be met satisfactorily, so that tubes of this

Beam bundles B _x , B ₂ and ß, go through the common type so far found no practical application

same focusing lens L through and will have through.

this deflected so that it appears on the screen 5. The following is now a cathode ray tube

converge. 5 with only one beam generation system for generation

In the case of a color cathode ray tube with one of three electron beam bundles, the radiation generating system (FIG. 2) is required and can be used in particular as a color picture tube.
that the three electron beams with a case in FIG. 5 shown embodiment angle Δ between the central electron beam, the beam generating system A is provided with three equivalent bundles B ₂ and each lateral electron beam ίο beam generating sources K _x , K ₂ and K ₃ , the bundles B _x and B ₃ converge in such a way that they are arranged on a straight line at distances d ₀ from one another in a ^{shadow plane arranged in front of the screen S 1} , which essentially cross or cut a mask or grid arrangement at right angles to the axis of the beam generating system! and each hit colored dots or stripes, runs. These beam generation sources K _x , K ₂ and K, which are used to emit different colored light beams, generate three electron beam bundles B _x , B ₂ and B _1. So that this requirement is taken into account with respect to the convergence angle / I which is refracted by means of a common auxiliary lens L ' se in a simple radiator, that the intersection of the averaging system is taken into account, it is essential to radiate the beam bundles B _x , B ₂ , B ₃ on the axis de: Hch that the electron beam B _x , B ₂ and B ₃ focusing lens L lies. The electron beam collars when passing through the focusing lens L exactly the 20 then emerge diverging from the focusing lens at a mutual distance d from one another. The outer electron beams B _x and B ₃ , the outer electron beams B _x and B ₃ go first from the axis and the one on this axis through the focusing lens L so that they are the distance from the running central electron beam B. the optical axis of the same d have WO diverge, then again in the direction of da: medium through the impingement of the beams on the image 25 by means of two electron beams B ₂ S Konschirm both due to the coma, and the spherically-convergence deflection devices F ₁ and F ₂ distracted aberration can be distorted, as shown on the right between the screen S and the focussing edge of FIG. 2 is shown. The focusing lens L is arranged at a distance 1 from this and the electron beam is set so that complete convergence is achieved on the screen 5 such a deflection of the electron beam. 30 cause the electron beams B _x , B. As a result, each electron beam and B _{3 will} converge on the screen S and the transmitted focusing effect will inevitably be reduced and overlap.

so that the electron beam is underfocused and in this training, as on the right edge of their points of impact, as shown in FIG. 2, it can be seen from FIG. 5 is shown, very small image points are enlarged. If the focusing voltage 35 becomes, since all three electron beams B _x , B. are set so that the electron beams B ₂ and B ₃ pass through the axis of the focusing lens L on the screen S a sharply focused image and is thereby prevented that results in the image point, the image points B _x , B ₂ and O ₃ points are scattered by coma and spherical aberration ver on the screen S , as shown in FIG. 3 be dragged or blurred. It is therefore shown a picture. It is therefore necessary to generate special measures 40 with high resolution.

are taken in order to remove the pixels thus scattered. In the embodiment according to FIG. 6 they are to be combined or stored one above the other. Like three beam generation sources K _x , K ₂ and K ₃ for the, however, from the illustration in FIG. 3 on the right - three electron beam bundles B _x , B ₂ and B _{1 of} the beam goes, the image points B _x and B ₃ are still distorted by the generation system on a curved surface and the coma. 45, the center of which is in the axis of the focus

When trying to find the contradicting Beier lens L lies. The beam generation sources have conditions for focusing and converging of the three electron beams on the screen S to and from the axis, in this case a straight distance d _{ox from one another.} In this embodiment, it could be thought that the three auxiliary lenses L ' of FIG. 5 is omitted because the electron beams B _x , B ₂ and B ₃ according to FIG. 4 of 50 electron beam bundles B _x , B ₁ and B ₃ due to the arrangement of a single radiation source K in three different voltage of the beam generating sources in the curved angular directions so that they are anyway on the surface on the axis of the focusing point where the focusing lens L is arranged, the lens L as in the embodiment according to FIG. 5 have a distance d from each other. Here you can cut. In the area of the beam path of the outer the two conditions explained simultaneously and 55 electron beams B _x and B ₃ are fulfilled at the distance I with only slight spherical aberration behind the focusing lens L, two convergence deflections. The image points of the side beams B _x and B ₃ devices F ₁ , F ₂ are arranged, through which the rear are, however, as shown in FIG. 4 can be seen on the right, the focusing lens initially blurs the diverging electron beam as before due to the coma, since the side electron beams O ₁ and B _{3 are} again deflected into convergent electron beams by the focusing electron beams, lens L pass through the equi- with each other and with the central electron-valence optical axis of the focusing lens, the bundle of rays B ₂ on the screen 5 have d together. meet. Here, too, as with the P. <isf ab

It can thus be seen that in the case of cathode ray tubes, the form according to FIG. 5, a clear high definition picture

of the known type formed with only one beam generating 65.

system for generating three electron beam As already mentioned, the focusing and converging forms according to FIG. 5 and 6 show the beam generating conditions for the three electron beams not swelling K _x , K ₂ and K ₃ on a straight line im

7 8

Distance d ₀ and d ₀₁ are arranged from one another. Instead of a larger diameter than the end parts 3, 4 of the

however, it is also possible to have the radiation generating electrode G ₃ and has a central section 8

swell, at the corners of an equilateral triangle of even larger diameter. Your arrangement

to be arranged, with convergence deflection devices is so that the rear end portion 4 of the elec-

F ₁ and F ₂ for each of the three electron beams 5 trode G _: , in the front end section 6 with formation

or a radial gap is provided for only two electron beams. The elec-

can be. Preferably, however, the trode G ₅ is provided with a central section 11 of the

Beam generation sources, as shown, on a central section 5 of the electrode 3 of approximately the same size

straight line, because this is the distance diameter and with end sections 9 and 10 of

of the electron beam from the optical axis io smaller in diameter than the rear end portion 7

reduced to a minimum, provided the dynamic condenser electrode G ₄ and intervenes with its

vergence correction facilitated and an asymmetrical end section 9 thereof, in turn, forming a

Convergence of the three Büdpunkte on the screen S of the radial space in the end section 7 of the

can be avoided. Electrode G _{4 on} . The electrodes G ₃ , G ₄ and G ₅ as well

Furthermore, in the embodiments according to FIG. 15, the grids G ₁ , G ₂ and the cathode K are shown in FIG

F i g. 5 and 6 the design such that the three positions explained by a carrier 12 made of insulating material

Electron beams B ₁ , B ₂ and B _{3 held together} on the image. Furthermore is around the rear

screen 5 converge. Instead, however, the end portion 10 of the electrode 5 can have a grid chamber Gr

the convergence deflectors F ₁ and F ₂ also arranged.

can be omitted, so that the three electron beam 20 to operate the electron beam system after they are on the axis of the focusing F i g. 9 are cut to the grid G ₁ and G ₂ and the Eleklinse, troden in diverging directions G ₃ , G ₁ , G ₅ voltages applied z. B. 0 run up to the screen and on this at 400 V on the grid G ₁ or the three different, spaced or in certain grids G ₁₁ , G ₁₂ , G ₁₃ , 0 to 500 V on the grid G ₂ , distance from each other, meet points. 25 13 to 20 KV at the electrodes G ₃ and G _s and 0 to In the case of such a design as shown in FIG. 7 and 8 can be 400 V at the electrode G ₄ , which is shown, the three voltage points on which the voltage of the cathode K is the reference voltage. The screen also does not impair ₁ generic aberration by coma or spherically voltage distribution for the Gittor and electrode G so that distortions to G ₅ as well as their lengths and diameters are or blurred Büdpunkte in accordance with the loading 30 equal to those indirectly unknown essentially of Executions according to FIG. 2 to 4 avoided heated beam generating system for generating one. If the beam points are spaced apart from each other by electron beam bundles in which a first grid element is formed on the screen S , the and a second grid element are transmitted with time differences each with a single opening image signal, which is arranged in the three voltages. At the specified voltage point points on the screen and 35 distribution, _{the three electron beams are modulated between the grid G 2} and the so that the front end section 3 of the electrode G _{3 forms} a lens between the three on the screen through the three field, which the Auxiliary lens L ' of FIG. 5 ent-electron beam generated images corresponds, while at the same time one of the focusing lens L of the mood is reached. F i g. 5 corresponding lens field through the elec-

In Fig. 9 to 12 is an embodiment of a 40 electrodes G ₃ , G ₄ and G ₅ in the axial center of the elec-

Cathode ray tube with one of the optical equi-trode G _{4 is} formed.

valent according to FIG. 5 corresponding radiation generation system Λ shown in one possible mode of operation of the radiation generation system. Here, the cathode K forms the supply system, bias voltages of 100 V, beam generation sources K ₁ , K ₂ and K ₃ . Closely behind 0 V, 300 V, 20 KV, 200 V, 20 KV in this row of the emitting surface of the cathode K is a first control sequence on the electrodes K or G ₁ , G ₂ . G ₃ , G ₄ and G ₅ grid G ₁ arranged, which according to F i g. 11 and 12 given three.

Has grid members G ₁₁ , G ₁₂ and G ₁₃ . These three so that those from the electrode G ₅ in divergent

Grating members are each with openings g _n , g ₁₂ and paths exiting electron beam B ₁ unc

g ₁₃ , which are arranged on a straight line B _{3 are brought} back to converge, there is:

are. Opposite the grating G ₁ is a second grating G ₂ 50 beam generation system according to FIG. 9 with an Ab

with three openings g ₂₁ , g ₂₂ and g ₂₃ arranged, the steering device F with at a mutual distance from

with the openings g _u , g ₁₂ and g _{13 of} the first mutually arranged deflector plates P and P ' ver

Cover grid G ₁ . The second grid can see cup-shaped, which extends in the axial direction from the free endi

be formed and have a disk I in which the electrode G ₅ extend from. The deflector

the openings g ₂₁ , g ₂₂ and g ₂₃ at a distance from one another 55. Device F furthermore has deflector plates Q and Q ' , dl

are arranged on a diameter line II-II and z. B. are convex bent or curved outward

from its peripheral edge a cylindrical and opposite one another on the outer surface)

Side wall 2 are attached in the axial direction of the grid G _{1 of} the baffles P and P '. The Ab

extends away. In this direction follow the baffles P and P ' and the baffles β to

Grids G ₂ rearward tubular grids or elec- tron 60 Q ' are arranged so that the electron beam collars

trode G ₃ , G ₄ and G ₅ (Fig. 9). B ₁ , B ₂ and B ₃ between the baffles 1, respectively

The electrode G ₃ has a central portion 5 of and Q between the baffles P and P ' un <

larger diameter and two end sections 3, 4 between the baffles P ' and Q' hii ^ -mchwalk

of relatively small diameter on and on the baffles P and P ' becomes a tension

engages with its front end section 3 applied below that of the chip applied _{to the electrode G 5}

Allowing a radial distance from the side wall 2 voltage is the same, while at the baffles Q un

of the cup-shaped grid G ₂ in this one. The elec- Q ' a voltage is applied, which by 203 to 300 ¹

Trode G ₄ is provided with end sections 6 and 7 which are lower than those of the baffles P and P '

guided tension. There are therefore between the system A according to the invention in its application

Deflection plates P i'nd Q as well as between the deflection in a chromatron-like color picture tube shown,

plates P ' and Q' generates voltage differences that Da,> the beam generating system has three electrically

the convergence deflection device F ₁ and F ₂ each have separate cathodes Kk, Kn and Kb .

and the respective deflection of the electrons - 5 to which red, green and blue color signals

Beam bundles B ₁ and B ^ in the sense of FIG. 5 can be shown. The three cathodes are arranged so

call. that theirs emit the electron beam

The electron surfaces emanating from the cathode K on a straight line and in alignment with the beam bundles B ₁ , B ₂ and B ₃ pass through the openings g _llt , g, e and g _X B gin Sn ^and d Sis of the lattice members, which are likewise arranged G _n , G ₁₂ and G ₁₃ ιυ of a plate-shaped grid G ₁ lie. Close behind therethrough and with three different signals to the grid G ₁ is a cup-shaped grid G ₂ is modulated, the arranged between the cathode K and the grid, the disc the grid G ₁ turned and broken C _11, G supplied to ₁₂ and G ₁₃ will. They are provided with three openings g ₂ n, g ₂ a and g iB, which then go through the _{openings shown in FIG.} 9, indicated by dot- _{dash lines, in each case congruent} with the openings g lR, g _t c and gjo auxiliary lens L ′, which lie mainly through the 15. As in the previously described embodiment grid G ₂ and the electrode G _{3 is} formed, and shape is the beam generating system with electrodes intersecting on the axis of the also dashed G ₃ , G ₄ and G ₅ provided, which are also indicated by dotted lines Focussing lens L, which are in that they form the electron lenses L ' and L indicated by dash-dotted lines _{through the electrodes G 3} , G ₄ and G ₅ .

forms is. The electron beams B ₁ , B ₂ and B ₃ 20 to the grids G ₁ and G ₂ as well as to the electrodes G ₃ , then after leaving the electrode G _5, G ₄ and G _{5 of} the beam generating system A are in each case between the deflection plates Q. and P, between the base of the cathode voltages, the voltages of the deflection plates P and P ' and between the offs, which are the in connection with FIG. 9 link plates P ' and Q'. Since the baffles P and P ' correspond to given voltages. Of the have the same potential, the electron 25 cathode Kr, Kg and Kb outgoing electron beam B ₂ is not deflected, while, BG, and BB pass through the apertures focusing lens L with divergent paths austre- from the beams B _R g _lR , g ^ and g ₁ ß of the first grid G ₁ and then the electron beam bundles B ₁ and B ₃ so deflected through the openings g ₂ n, g _{2 (;} and g ₂ "of the second, that they are deflected at one point the image grid? G ₂ and then through the auxiliary lens L ' . scLirm converge. 3 ° by which the electron beam is deflected in this way

In the embodiment according to FIG. 9 to 12 it is that they are in the lens field of the focusing lens L.

required that the signals intersect the three grating members on their axis. The electron beam

G ₁₁ , G ₁₂ , G _{13 of} the first grating G ₁ supplied separately bundles B _n and Bu emerge from the focusing lens L in

are, since the three radiation sources K ₁ , K ₂ and K ₃ in diverging directions, but then

a single cathode K are arranged. So that this 35 converges by a deflection device F

is achieved, the three rectangular lattice members are directing the convergence deflectors F ₁

G _n , G ₁₂ and Gi ₃ , in each of which the openings g _n , and F ₂ to F ^; G. 9 and 5 correspond and again

g ₁₂ and g ₁₃ are arranged, with baffles P and P ' and baffles Q from them

outgoing connection pins 13 for receiving the signals and Q ' . The by this deflector

for the independent modulation of the electron beams ß «, which are deflected in a convergent manner.

provided beam bundle. Be and Bu hit a screen S after

So that the mutual position of the openings g _u , g, ₂ they jng by a Strahlauswahleinrichi such. B. one and g, _{3 of} the grid members G ₁₁ , G ₁₂ and G ₁₃ exactly fixed-perforated electrode or shadow mask Gp placed and passed through openings g ₂₁ , g ₂₂ and g _{23 of} the second, which are in front of the screen S ange-grid G _{2 is arranged} at a certain distance D (FIG. 12) 45 and to which a medium-high voltage Vy are brought concentrically into congruence are applied. The screen S is with groups in front between the grids G ₁ and G ₂ according to FIG. 11 red, green and blue phosphorescent strips and 12 two ceramic insulating pieces 14 arranged, provided with Sn, Sg and Sb , which are arranged one after the other, each with a thickness corresponding to the distance D , on a front plate F _P. To have ab. Each of these insulating pieces 14 is provided on a 50 ienkplatten P and Q and P 'and Q' of the deflection before the entire surface with an electrically conductive cover direction F, voltages Vp and Vq are applied layer 15, which are selected on the corresponding surface, that the three electrons z. B. can be formed by metallizing the same. bundles of rays Br, Bg and B _B at the point of scnneider In addition, three electrically conductive layers M ₁ , on which the shadow mask Gp is arranged, and s Ai ₂ and M ₃ are arranged, each of which extends over the 55 only on the corresponding strip Sr, Sg and 5 width of the opposite face of each insulating arrive. In this case the electron pieces 14 will extend and evenly spaced beam bundles B _R , Br, and Br, since they are at the shade from each other. The insulating strips 14 converge on the mask Gp , focused on the screen pane 1 of the second grid G ₂ in a symmetrical fresh position.

attached to the line 11-11, on which the openings öo For horizontal and vertical scanning of the dr

g _2l , g ₂₂ and g., 3 are arranged. You are doing this at the electron beam simultaneously with respect to de

Slice of the second grid with its conductive layer screen like be < known picture tubes are well known

th 13 ζ. B. annoyed by brazing. The grid horizontal and vertical deflection means in Fr τη di

members G _n , G ₁₂ and G ₁₃ bridge the distance bracket D arranged.

between the insulating pieces 14 and are, for. B. also 65 If the color picture tube according to F i g. 13 red, green

by hard soldering on the conductive layers M ₁ , M _% and blue color image signals between the cathodes K

and M _{3 of} the insulating pieces attached. K ₀ and Kb and the grid G _{1 are} supplied,

In Fig. 13 is an example of a beam generation experience, the three electron beams Br, Bg ui

Bn a brightness modulation, whereby a colored picture is generated on the screen.

In the embodiments according to FIG. 9 and 13, the convergence deflection device F is of an electrostatic type. 'nts F are used, as shown in Fig. 14A and 14B Such magnetic deflection F' has a magnetic shield 15 in the form of a tube of rectangular cross-section which g in the axial direction behind the in F i. 14A, electrode G _6, not shown, is arranged so that the central electron beam B ₂ according to FIG. 9 or Bg according to FIG. 13 can go through it. On one side 16a of the shielding 16 (lower side in FIG. 14 A. and 14 B), two magnetic plates 17 a and 176 are arranged opposite one another at such a distance that the electron beam B ₁ and Bn pass between them can. On the other side 166 of the screen two magnetic plates 18a and 186 are mounted in the same way, between which the third electron beam B ₃ and Bb can pass. The ends of the plates 17σ, lib and 18a, 186 facing the shield 16 are, as shown in particular in FIG. 14B can be seen, preferably bent so that they converge towards the shield 16, while the outer ends 19o and 196 of the plates facing away from the shield are preferably each bent outwardly away from one another and run along the inner wall surface of the neck part of the tubular piston N , the by the dash-dotted line in FIG. 14B is indicated. The outer ends ? Ϋα and 206 of the plates 18σ and 186 are bent outward in the same way and, like the ends 19a and 196, form magnetic poles. On the outside of the tubular piston N , electromagnets 21 and 22 are arranged opposite one another, each of which is provided with the windings 23 and 24 that end the magnet cores 25 and 26. The magnetic core 25 has magnetic poles 25a and 256 facing the magnetic poles 19a and 196, while the magnetic core 26 is provided with magnetic poles 26a and 266 facing the magnetic poles 20a and 206.

In the arrangement described, the three electron beams B ₁ , B ₂ and B ₃ , after they have intersected on the axis of the focusing lens L and have emerged from the electrode G ₅ , each between the magnetic plates 17 a, 176 through the Shield 16 and between opposing magnetic plates 18a, 186 therethrough. The electron beam B ₂ is not deflected here because it is shielded from the external magnetic field by the shield 16. The electron beams A ₁ and B ₃ , however, are deflected by the magnetic flux between the magnetic plates 17a and 176 and r-wiping the plates 13a, 186, which is caused by the steady convergence current flow through the electromagnets 21 and 22, so that the three electron beams B ₁ , B ₂ and B ₃ converge in the desired manner either in the image point of the screen or on the shadow mask arranged in front of it. The static convergence currents flowing through the electromagnets 21 and 22 can also be superimposed by dynamic convergence currents, so that in this case a special dynamic convergence is not necessary.

Characterized in that the sides 16 a and 166 of the Abts catch screen 16 facing inner ends of the magnetic plates 17 a, 176 and 18 a, 186 according to FIG. 14B are bent converging inward, the electron beams are guided very close to one another or along the shield 16, so that it is possible to disturb the magnetic fields on the beam path of the electron beams B ₁ and B ₃ by the magnetic flux from the magnetic plates 17a, 176, 18a, 186 to avoid the magnetic shield 16 effectively. This also avoids distortion of the pixels on the screen. If the distance between the opposing magnetic plates is α, the length of the bent part of each of these plates is c, the distance between the free edges of the converging inner ends is 6 and the small rectangular side of the shield 16 is d , then for best results, though

b \ a = 0.625; - = c \ a = 0.325
2a

and the angle between the inner bent ends is about 30 to 60 degrees. If the inner ends of the magnetic plates facing the magnetic shield 16 are not bent, the magnetic field is not evenly distributed because the magnetic flux on the path of the electron beams O ₁ and B _{3 is} under the influence of the. ignite flux from the magnetic plates 17a, 176 and 18a, 186 to the shield 16 is bent. The distortion caused by such a non-uniform magnetic field becomes particularly large if the distance between the adjacent electron beams is reduced so that the electron beams come close to the side face of the magnetic screen 16. However, such distortion can be effectively avoided if the magnetic plates are bent as described.

The electromagnets 21 and 22 can also be replaced by permanent magnets.

For this purpose 2 sheets of drawings

Claims (7)

1 2 Potential of the next electrode (G3) patent claims: has a different electrical potential. 1. Cathode ray tube with one or more Beam generating systems for generating multiple 5 Electron beam, with a screen, against which the electron beam bundles are directed The invention relates to a cathode ray tube with, as well as with one or more beam generating systems common to all beam bundles for seeding and the beam bundles on the bi-screen generating multiple electron beam bundles, with a focusing lens, in which the io Screen against which the electron beam bundles are directed at a single one, as well as with a point between the location of the beam generation and the common and the beam bundles on the screen of a beam selection device in one point focusing lens, in which the center cutting points , characterized in that the beam bundles radiate at a single point that the intersection of the central beams of the beam 15 between the location of the beam generation and a bundle (B ₁ , S _2. B ₃ ; Bn, Ba, B _Jt ) so in the field of the beam selection device cut in one point, rokuss ierliiisi (L) lies on its axis, so that only one such cathode ray tube is known to be used in an area of the lens field close to the axis (e.g. 3. U.S. Patent 2,690,517) and a tube is used as the color image. The known color picture tubes are 2. Tube according to claim 1, characterized by marked 20 mostly with three independent beams that the focusing lens (L) provided several electron beam bundles applied to generating systems for emitting each of a different electrical voltages, which by corresponding electrodes (C ₃ , G ₁ , G ₅ ), which modulates a focus color signal and generates an electron lens field through a grid system. be influenced that they are juf a screen 3. Tube according to claim 1 or 2, in which the 25 is focussed, which is provided with a beam arranged in front of it, beam selection device such as a perforated electrode or a shadow mask, emitted by the beam generating systems, beam selection device, substantially parallel to one another. Derv.erden, characterized in that between the like color picture tubes, in which the three beam generating systems. (K., K ₂ , K ₃ ; Ka, Kn, Kh) and generating systems must be mutually aligned in such a way that the focusing lens (L) and an auxiliary lens (L ') must be arranged so that the emitted electron beam bundle that causes cutting is arranged of the central rays that converge on the screen are bundles on the axis of the focussing lens disadvantageous, as a precise alignment of the beam guides, generating systems and the maintenance of this orientation. 4. Tube according to claim 3, characterized in that the identification direction is difficult and any deviation from the fact that the Hil'sünse (L ') several electron beam bundles emitted on them, an elec- trical voltage applied to the image quality and the resolution electrode deteriorates or grid (G ₂ , G ₃ ). Property of the color image evokes. In addition, 5. Tube according to claim 1 or 2, characterized ^ e- calls for a work with three beam generation systems that the beam generation systems tend color picture tube and can (K ₁ , K. ,, K ₃ ) are arranged on a carrier 40 because of the space requirement for these Strahlerzeugungsdaß cutting the central rays of the beam systems with a relatively large Minbündel (B _1, B ", _Β Ά) on the axis of the focusing be prepared least size. lens (L) is brought about (Figs. 6 and 8). To avoid these disadvantages of the known 6. Tube according to claim 5, with three Sirahl color picture tubes mii several beam generation systems for generating 45 men each has been proposed to use a color picture tube with a beam, characterized in that the only one beam generation system to be used, which has a beam generation system (Kc) in the optical either with three cathodes or with only one Ka-axis of the focusing lens (Z.) and the two method generates three electron beams that pass through other beam generating systems (Kn, Kn) both - a lens-like focusing system, on the one hand at the same distance from the same so that they converge on the screen. In the case of a construction proposed through the optical axis, however, only straight lines are arranged in such a way that one of the electron beam bundles is arranged on the optical axis so that only the other two beam axes of the focusing system pass through it, generating systems (Kn, Kn) outgoing beam while the other two leave the focusing lens at a distance from the bundle ^ 8 _]} , Bn) on paths diverging from the electron beam lens axis passing through the 55 optical axis. bundle the coma and spherical aberration 7. Rölue according to claim 4, characterized thereby exposed. For this reason and because of the fact that the second grid (G ₂ ) in the form of an associated deterioration of the simple _{color image containing openings (g 1, g 22} and g ₂₃ ) have color picture tubes with only one pane (1) _{is behind which the electrodes (G 3} , G _{4 electron beam and G 5} ) forming the 60 beam generating system for irradiating multiple focusing lenses (L) are not found in a widespread use, successively with tubular shapes. staltuiig and various electrical poten- The invention is based on the object of a Tiale are arranged, and in that the cathode ray tube of the type described above To design disk (1) on its peripheral edge for formation 65 so that the aberrations are reduced the auxiliary lens (L ') with one of the focusing lens and the resolution improved, turned cylindrical side wall (2). The object is achieved according to the invention by is blind, the one opposite to the electrical one that the intersection of the middle rays of the ray