DE1964180C - Convergence deflection system for a cathode ray tube - Google Patents

Description

The invention relates to a convergence deflection system 60 which is at the same potential as the one close to the axis for a cathode ray tube to achieve the Kon plate.

vergence of diverging from a focusing lens through the grid-shaped auxiliary electrodes, which from

emerging bundles of rays, for each diverging the electric field between the corresponding The bundle of rays emerging from the axis of the tube is due to two plates close to the axis and on the axis In the direction perpendicular to the agitator axis at a distance of 65 their lattice structure penetrated, plate-shaped electrodes arranged on top of one another - the potential gradient in the area of the electrical between which the respective bundle of rays see through the field, that of the bundle of rays in question occurs and in which the plate near the tube axis is traversed, relatively lowered.

3, the potential gradient in this area is in * Essentially constant and almost independent of variations in the plates close to the axis Htasr

_re nhals seated B _B and Bn occur ver d'

out

.,,. _{= £ r} i5

3Hä SSHSSSSS

»5

There is another possibility therein, the grid-shaped auxiliary electrode «from s.ch crossing wires. _

The invention is explained below on the basis of the drawings explained: It shows.

Fig. 1 in a schematic representation of a view .m axial section of a known multi-beam tube mu a single electron gun and e.nem electrostatic Convergence deflection system;

F i g. 2 is a schematic representation of a view ,, oak represents the character of the electric field,

that between the two plates in the electrostatic Convergence deflection system according to Fi g. I to deflect what is passing between these plates Beam is generated;

F i g. 3 one of the F i g. 1 similar view, but of a cathode ray tube with an electrostatic connection

Convergence deflection system according to an embodiment of the invention; .

F i g. 4 one of the F i g. View similar to Fig. 2, but showing the character of the electric field, that between the two plates in the convergence deflection system of FIG. 3 is generated;

F i g. 5 shows a graph of the voltage distributions and the field strengths at two points between the in F i g. 4 plates and shown

F i g. 6A, 6B, 6C and 6D are schematic and diagrammatic Views of auxiliary electrode arrangements which, instead of those shown in FIG. 3 and 4 illustrated arrangements can be used

The following is a more detailed description of Multi-beam color picture tubes with a single electron gun are referred to, however, the Electrostatic convergence deflection systems also find application to other cathode ray tubes which several bundles of rays must be brought to convergence in front of the screen in an unnecessary way.

In Fig. 1 shows a known multi-beam Ka hodei jet tube with an electron gun IC. The electron gun K produces dre. Beam bundle ß «, Bc and Bn. The bundle of rays Ba runs on the tube axis. The three bundles of rays are sent in a known manner d, ah a mill lens L ' , which deflects the two outer bundles of rays so that the field of an electronic focus lens is close to the axis Tick LU . The all sm, hlbunddn gen « " _nd
andj ^ j

_while the outer plates P 1 diverge, as shown, or _to | _ears axis extend. The ₂ 'and the plates P ₁ and P ₁ are % ß the bundles of rays Bn, Bo and *. Plates P ₁ and P ₂ , between the plates _ρ , _{and between} the plates P ₂ and P ₁ h ^ m ^ step. A tension that be.sp.eswe.se

_passes ^r *, _is applied to the plates P,

J ^ ch de ^ AP ^ _ungi de around 200 to

and I », g £ g ^ _e . ^ _dje the plates P. 300 V nieor g _{the plaUen} ^ _d ^ _e , e _g

and Γ, gel * ^^ ^ ^ ^ on the one hand and the PHtten P 'and P ₁ ' on the other hand, there are thus bpan-

™ " ^e " _n ^ _rs "Ji _ede ^l which deflect the bundles of rays Bn and B _n now * underneath ^ ^ ^ _{deflect D}

^ ^m "J ^ _{latten Ρχ and} P ₁ 'as well as on the pat th J dp. of _the convergence _{deflection system F.}

J «""J Λ« _K „ _{and Κρ} , are chosen so that the voltages y ^ and r, ^ ^^ _hl

4 <> three ^{S rahl} ~ _d / _r ' _{position de} r beam _selection ^{preselection de} J'«" * ° for example a grid or a hole ^^^^ "" ^ cut,
arte _: « ^{n tt} · _{the plaUen p and Pad} es know-

, J Konwrenzablenksystems F shows, it can be seen, te η KonwrgenzaDwn y _{sje himlurchlnt} ,

Jß the StraWbundel ß "^ ^ _{between |} .

_{because of the} electricity _generated ^ _d

Lines pichen potential through the letter / Linierι equate r ^ _{deflection of the out} -

so stated s.nd. Per g _{determined by d} , _e

through Mra _{distance rf 2W} j _en

Stress tolerance, _{distance f / h}

the plates P unü r _s ^ _{wjrd de} ,

the. ™ ^ ^ _n J of _{the beam} under the effect of the Ab en Kg voltage differences

des Kldes only mentioned, verur

^^^^ Seniension to one of the plates. ^s ^ _p ^h _p 7'J _r ^e _d ⁿⁿ _b ^U e _{for example} e on the plate P ₂ and a <sometimes w rd ^ ⁰¹⁵ ^ _{iclweise by} 200 to 300 VoI 5o lower ^S P; ⁿⁿ ""J; ^ ^l ^ g _tte ρ _ge | _e gt, changes njedngej. «^ J ^ de ^ latte g ^ g ^ _ver

rungen η «; An ^oüe J ^ _m ^ _changes andeπ ng« = ⁿ ™ £ * '* _d ,, _{ckleS) where changes} due to the At £ Ξ' Älbindclfl «and Bn ,

in the above-described convc

genzablenksystem the lower potential Vp ₁ equally agile. To simplify the circuit, how

the earth potential or zero is chosen to mention the _one placed on the off-axis plate P 1

thereby avoiding the switching arrangement, the emergency voltage K ₁ as ground potential and the auxiliary

v is end to generate the voltage that is placed around 200 electrode 12 and the near-axis plate P ₂

up to 300 volts lower than the anode voltage V _P% , 5 voltage equal to the anode voltage of the tube

the stress gradient is very large, as selected by the.

Line V _n in FIG. 5, and the obtained elec- In this case, the electric field and the

The Irish field is too strong to divert the rays correctly. Stress distribution between the plates P ₁ and P ₂

to steer. and the auxiliary electrode 12 as in FIG. 5 shown.

The undesired misconvergence of the beam, io The strength of the electric field and the voltage

caused by changes in the anode voltage distribution in a plane AA, which covers the space

is caused when this tension is applied to the axis between the wires W ₁ and W ₃ in FIG. 4 halved,

Nearby plates P ₂ and P _{1 of} an electrostatic con are shown in FIG. 5 indicated with Ea and Va, respectively, while

vergence deflection system, the strength of the electric field and the voltage

avoided having an auxiliary electrode between the plates 15 distribution in a plane BB which passes through the center

P ₁ and P ₂ as well as between the plates P ₁ and P _{1 in} front of the wire If ₃ , indicated by E _n and V _n, respectively

is seen. The auxiliary electrode is essentially. In Fig. 5 are the increasing tension and

borrowed the same relatively high voltage as the increasing strength of the static field due to the

on the near-axis plates P ₁ and P ₁ . For example arrows V and E indicated, while arrow X denotes

possesses, as in FIG. 3, in which the illustrated 20 shows the distance from the off-axis plate P ₁ and

The tube is otherwise the same as the one in connection with d, and </ ₂ the distances from the auxiliary electrode 12

F i g. 1 is described, the electrostatic Koriver- to the off-axis plate P ₁ or to the off-axis

Gene deflection system F ' for the beam bundles Bn and Bn. Plate P _{2 are} designated. With d ₃ is the distance

that of the focusing lens Lm diverging longitudinally between the near-axis plate P ₂ and a plane / ',

Paths emanate, in addition to the on-axis and 25, which are located between the auxiliary electrode 12

off-axis panels P ₂ and P ₁ or P ₁ and P ₁ ', which and the near-axis panel P ₂ is located and to which

along the respective diverging paths on which the influence of the auxiliary electrode 12 the existence of a.

Inside and outside, in relation to the tube axis, _{causes tension K 4} , which is significantly higher than the

xx are arranged, auxiliary electrodes 12 and 12 ', which is the one that is in such a plane P ₄ at IcIiIeπ

along the outer sides of the respective diverging 3 ° of the electrode 12 is obtained.

Lanes are arranged and at a distance As mentioned, if the auxiliary electrode 12 .m-

inwards from the axially remote plates P ₁ and P _{1 to} the one in FIG. 3 and 4 shown convergence deflection

condition. These auxiliary electrodes 12 and 12 'are systematically omitted and the illustrated

open areas shown, for example by th stresses K ₁ and K ₂ on the plates P ₁ and / .-

the spaces between parallel conductive wires 35 would be a very steep slope

are formed. Voltage V ₇ , can be obtained as in I-i g. 5 gc / eiiM

From I- i g. 4, which only has the plates P ₁ and P ₂ and and this steep increase in voltage would not 711 a '

between these the auxiliary electrode 12 shows, and lead with perfect convergence of the beam bundles

Consideration of the fact that the plates P ₁ If, however, the auxiliary electrode 12 between ilen

and P ₂ 'as well as the auxiliary electrode 12' is provided in the same 40 plates P ₁ and P ₂ , an essentially

Wcisc work, it follows in particular that the borrowed linear increase in voltage V _A O'n). dc ^r

the axial plate P _{2 applied} stress K ₂ as well as the significantly less steep than the increase in the stress

the voltage applied to the auxiliary electrode K ₃ is essentially '", between the plate P ₂ near the axis and the

are the same relatively high voltage V _n . Level P, available. This stress gradient is im

which can be the anode voltage of the tube, 45 area d ₃ between the axis Piatie P ₂ and the

while the off-axis plate P, a relatively low auxiliary electrode 12, which the beam B traverses

Voltage K ₁ has. which can be the earth potential. will, regardless of changes that are not too big

_{The voltages K 1} , K _{2 of} the anode voltage applied in this way, which are applied to the plate P ₅

and K _a generate an electric field between which is placed, essentially constant,

achsennahcn and the off-axis plate P ₂ and P ₁ . 50 The tension K ₄ at the point in the field caused by du

which is in the area d _{3 of the} same, which is indicated _{between the plane P 4.} is lower than the Spannuni

plate P ₁ close to the axis and the auxiliary electrode 12 be K ₂ . which is placed on the near-axis plate P ₂ . This hai

and the result of the respective bundle of rays Bh is that an electric field of strength Li,

will run, a relatively low voltage gradient - that for the correct deflection of the passing through

th, which is suitable regardless of changes in the 55 beam, between the auxiliary electrode 12 µm

The anode voltage K _n remains essentially constant, the plate P _x close to the axis is maintained. This elck

so that a misconvergence of the bundle of rays in the vertical field is caused by the field which lies between

is avoided. of the off-axis plate P ₁ , at which there is earth potential

In the case of the in FIG. 3 and 4 shown embodiment and the near-axis plate P ₁ , on which the anodes

shape of the auxiliary electrode 12, it is created by a parallel voltage that is generated and by the more open

f. arrangement of straight conductors W ₁ , W *. W ₃ , H ₄ , H ₆ surfaces of the auxiliary electrode 12 penetrates, ar

_v formed. For the purposes of the description, there are five which also lie and deviate from the anode voltage

. Head shown, which are spaced apart from the voltage gradient of the field in the area

and, with reference to the 1 longitudinal axis xx, are between the auxiliary electrode 12 and de ·· near the axis

r of the tube extend in the transverse direction. The auxiliary 65 plate P ₂ lowers. As the tension of the auxiliary

Electrode 12 can be essentially parallel to the plates, corresponding to a change in de

^e all! can be arranged as shown, but this is changed for the anode voltage, which is related to the axle value

^v avoiding Konvcrpenzfchlern no need plate P is placed _2, the effect of the Elektrod

12 consists in keeping the voltage gradient in the region d ₃ essentially constant regardless of changes in the relatively high anode voltage of the plate P _{2 close to the axis.} Furthermore, in FIG. 5 E _a the field strength in the area d _t between the electrode 12 and the off-axis plate P ₁ .

In a particular example of the embodiment according to FIG. 3, the voltage applied to the off-axis plate P _{1 was} 0 volts, the voltage (K ₃ , V ₂ ) applied to both the auxiliary electrode 12 and the plate P ₂ near the axis was 20 kV, the distance d _x between the auxiliary electrode 12 and the off-axis plate P ₁ 5 mm, the distance d ₂ between the electrode 12 and the inner plate P ₂ 9 mm, and the wires forming the auxiliary electrode P ₃ had a diameter of 0.2 mm and a distance between the wires of 1 mm. With the aforementioned dimensions and voltages, the field strength E _a between the electrode 12 and the plate P _{1 is} 4000 V / mm, while the field strength Et between the auxiliary electrode 12 and the inner plate P _{2 is} 116 V / mm so that there is a substantial decrease in the voltage gradient associated with the deflection field traversed by the beam. In the case of the in FIG. 3, the electrical deflection field, which is intended to cause the convergence, is generated between the plates only as a result of the voltage difference between the anode voltage and the earth potential, and there is no need to additionally provide a voltage that is, for example, 200 to 300 volts lower than is the anode voltage. Although this field depends solely on the anode voltage, which can change with respect to the earth potential, the voltage gradient of the field in the area between the auxiliary electrode 12 and the plate P ₃ close to the axis is kept essentially constant. As a result, a desirable electric deflection field for proper beam convergence is obtained, and mu ⁽ convergence of the beams due to changes in the anode voltage is avoided Obtained convergence unit, which requires no additional circuitry nor clamps for applying additional voltages to the tube, and such voltages can easily be applied within the tube structure. However, voltages other than the ground potential and the anode voltage can be applied to the plate P ₁ as well as to the

ίο plate P ₂ or to the electrode 12, if desired, are placed within the scope of the invention. With the use of the auxiliary electrode arranged between the convergence plates and the voltage ratio described above, the convergence of the beams can easily be achieved.

It should be noted that the auxiliary electrode provided can have many different shapes other than the parallel arrangement of straight conductors spaced from one another and extending transversely to the tube axis, as shown in FIG. 3 and 4, or extend parallel to the tube axis, as in FIG. 6A. So z. B., as shown in Fig. 6B, the auxiliary electrode 12B can be a plate, which is connected by a conductive mesh of

² S other connected conductive wires extending in the longitudinal direction and in the transverse direction is formed.

With further in F i g. 6C and 6D the auxiliary electrode can be a plate 12Γ

or 12/3, which is provided with openings, wherein the openings of the embodiment of FIG. 6Π more numerous and smaller than those in the transverse direction elongated openings of the embodiment according to FIG. 6C are.

Of course, for all of the! Ι Embodiments of the auxiliary electrode the degree or extent to which the electric field passes through it penetrates, can be changed to the voltage gradient of the field in the area between the Auxiliary electrode and the inner plate and thus change the deflection of the beam passing through.

1 sheet of drawings

309

Claims (7)

964 180 ι 2 with respect to the plate remote from the tube axis at positive potential lies 1. Convergence deflection system for a cathode 5 & Televisione Receivers ", BTR 14, July 1968, No. 2, ray tube to achieve convergence from p. 19 to 27). . . .
diverging from a focusing lens The amount of deflection experienced by a bundle of rays exiting between a bundle of rays and a bundle of rays diverging from the plate close to the axis and an off-axis plate in the tube axis depends on the distance between the direction perpendicular to the tube axis Plates generated an electric field. In the mutually arranged plate-shaped electro-known electrostatic convergence deflection system, between which the respective beam hangs the electric field, which passes through the deflection of the bundle and in which that of the tube beam bundle and thus its convergence with the plate close to the axis of the tube axis The difference between the anode voltage, which is characterized by the fact that each of the plates close to the axis is acted upon, and the tension of the plate close to the axis and the associated axis opening, with which acts on the plates remote from the axis (P ₁ , P ₂ ; P ₁ ', P ₂ ') on the plate from the axis. The last-mentioned voltage is several remote PIaHe (P _1, P ₁ ") facing side of the intermediate 100 volts lower than the anode voltage. The see the plates by passing beam 20 anode voltage may be a function of a (ßß, Bn) a grid-like Auxiliary electrode (12, 12 ') change in the operating conditions of the tube with distance to the off-axis plate (P ₁ , P ₁ ) change, for example, depending on changes and that the auxiliary electrode (12, 12') struggles in the brightness of the image on the screen, essentially at the same potential (V ₂ ) The voltage of the off-axis plates, which is more than the plate near the axis (P ₂ , P ₂ '). 25 is 100 volts lower than the anode voltage 2. convergence deflection system according to claim 1, but a relatively constant value inde- pendently characterized in that the potential (V ₂ ), depending on changes in the anode voltage, on which the two near-axis plates (P ₂ , P ₂ ') This has the consequence that the changes in the and the two grid-shaped auxiliary electrodes anode voltage changes in the voltage under- (12,12 ') lie, equal to the anode voltage (V _n ) 30 differentiated between the near-axis and the off-axis of the cathode ray tube, and that the two plates cause changes in of the off-axis plates (P ₁ , P ₁ ') are at ground potential. Deflection of the beam due to the changes. in the electric field between the axially and 3. Convergence deflection system according to claim I off-axis plates are caused. this leads to or 2, characterized in that the grating 35 a misconvergence of the beam, which is a misshapen Auxiliary electrodes (12, 12 ') of a much-desired influence on the image. number of conductors (12/4) are formed, which are parallel. and run at a distance from each other. An additional circuit was needed to avoid errors 4. convergence deflection system according to claim 3, required, whereby the circuit structure of the condo characterized in that the conductors (12A) run transversely 40 vergence deflection systems in an undesirable manner in a complicated manner to the tube axis. became more graceful. For example, one of these 5. convergence deflection system according to claim 3, attempting an undesired additional circuit for characterized in that the conductors (12/4) change in relation to the lower voltage Run in the direction of the tube axis. to the changes in the anode voltage 6. convergence deflection system according to claim 1 45 applies to a constant voltage difference or 2, characterized in that the grid between the near-axis and off-axis plates shaped auxiliary electrodes (12, 12 ') each by one to maintain. with openings provided plate (I2C, XID) ge The invention is based on the object that forms are. Convergence deflection system described above 7. Convergence deflection system according to claim 1 50 type to improve that convergence or 2, characterized in that the grid deviations as a result of fluctuations in the anode-shaped Auxiliary electrodes (12, 12 ') are largely avoided from a multivoltage. number of mutually longitudinal and transverse The object is achieved according to the invention, conductive wires (12ß) are formed. that between the near-axis and the assigned 55 listeners off-axis plate on the off-axis plate Plate facing side of the between the plates Arranged through beam bundle a grid-shaped auxiliary electrode at a distance from the off-axis plate and that the auxiliary electrode is essentially