DE2018943B2 - CATHODE RAY TUBE - Google Patents

Description

The invention relates to a color display tube with a single electron gun for the generation of several electron beams, with one screen, the arrangements of different Carries color phosphors and from the electron beams to excite the associated phosphors of the assemblies is acted upon, with an electrostatic focusing lens arrangement for focusing the electron beams on the screen, and having means for directing the electron beams so that they form acute angles to each other and cross at one point.

For color display tubes with a single beam generation system for several electron beams according to an older proposal (see German patent application P 16 39 464.2-33) several electron beams are emitted from a cathode arrangement and converges so that it is at a point between the cathode assembly and the screen, on which the rays impinge, cross or intersect, with a single focusing lens for focusing of all rays on the screen is arranged so that their optical center is essentially located at the crossover point of the rays, creating coma and spherical aberrations that cause the Rays impressed by the focusing lens can be significantly reduced. If the rays are like that are converged so that they essentially cross at the optical center of the focusing lens, at least certain of the rays emerge from the focusing lens along diverging paths, and Pairs of convergence baffles are arranged along these diverging paths and with tensions applied to deflect the diverging rays so that all rays at a common Point on a color selection electrode (e.g. shadow mask) converge in front of the screen, or it is allowed to the diverging rays on the color selection electrode at a distance from each other Points impinge, the color signals undergoing suitable delays by which the rays so can be modulated so that a correspondence of the images produced on the screen is obtained. In each Trap act on the rays of magnetic fields, which are generated by the supply of horizontal and vertical deflection

Signals to the corresponding coils of a deflection yoke arise so that the rays scan the screen with the desired grid,

In such a color display tube, the single focusing lens must have a sufficiently large one Have refractive power to focus the rays on the screen, d. ii. an optical lens with strong Curvatures (equal to small radii of curvature of the lens surfaces), which is why the rays, even if they only pass through the near-axis area of such a focusing lens, certain experience optical aberrations.

Similar problems arise with a known color display tube having a similar structure (see German Auslegeschrift 1 024 175).

Even if the proposed color display tube, the beams converge so that they essentially intersect in the optical center of the focusing lens by placing an auxiliary lens <* between the beam generation system and the focusing lens are provided, the rays that pass through the off-axis Pass the area of the auxiliary lens, optical aberrations through the auxiliary lens exposed to the one can have low refractive power in order to keep these aberrations as low as possible.

The object of the invention is therefore in the color display tube of the type described, the optical aberrations of the röhrenach sen distant rays when Focusing on the screen will reduce the result even further.

Likewise, a color picture tube of the type described is to be created by the invention which the diametrical size of the rays at the point of their intersection with one another is so limited that the rays hit the screen at sharply defined points.

This object is achieved in that the focusing lens arrangement is formed from several individual lenses, one behind the other along the tube axis are arranged and in each case several electrodes at different electrical potentials have that at least one lens of the individual lenses between the point of intersection of the electron beams and the single electron gun is arranged and that at least one other lens of the individual lenses between the Kreiizungsstelle and the screen is arranged so that those passing through one and the other lens are remote from the axis of the tube Rays subjected to opposite aberrations through one and the other lens.

Since, according to the invention, the focusing lens is formed by a plurality of individual lenses, each lens can be relatively weakly curved, i.e. have a low refractive power, around a total refractive power the focusing lens sufficient to focus the rays on the screen. Furthermore can the lenses which are arranged before or after the crossover point of the rays are opposite to the rays Imprint optical aberrations that cancel each other out and thus the rays of Completely free optical aberrations on the screen, even if the strai.len through an auxiliary lens to the Be brought across.

An advantageous development of the invention is that one electrode of the electrodes on the Crossing point of the electron beams is arranged and has a limited * · opening to the diameter limit the penetrating electron beams and thus create a sharp luminous ceiling on the Generate screen.

The invention is explained in more detail with reference to the drawing. It shows

F i g. 1 shows a sectional view along a horizontal plane through the axis of an embodiment Color display tube according to the invention with a single electron gun for several Electron beams,

ίο F i g. 2 a fig. I look like a variation the color display tube of Fig. 1,

F i g. 3 shows a partial sectional view according to a further modification of the embodiment according to FIG. 1,
F i g. 4 a fig. 1 similar view of another embodiment of the invention.

F i g. 5, 6 and 7 are schematic views of further embodiments of the invention.

The in F i g. 1 illustrated color display tube with a single electron beam generation system for several electron beams, to which the invention is applied, has a glass envelope (not shown) with a neck and a funnel-shaped expansion extending from the neck to a color screen 5, which with the usual Arrays of color phosphors and is provided with a color selection electrode Ag . Inside the neck is the single electron gun with cathodes Kr, Kc. and Kb , the beam emitting surfaces of which are arranged in the manner shown, so that from

electron beams Br, Br. and Bb emitted from them are aligned in a substantially horizontal plane which contains the axis of the single electron gun, the central beam Br, coinciding with this axis and the side beams Br and B _n converging on the axis. A first grid arrangement G ₁ of first grids G ₁ R, G ₁ G and G ₁ H is located in front of the radiation emission surfaces of the cathodes Kr, K _a and Kb and is formed with openings g ^ R, g _x o and £ i η , which with the respective beam

emission areas align. A common grid G ₂ is located in front of the first grid arrangement G ₁ and is provided with openings £ ₂ / ;, g ₂ n and g ₂ B , which are provided with openings g _x r. g _x r. or g _t r align. Away from the common grid G _2. successive in the axial direction. tubular electrodes G ₃ , G ₄ , G ₅ , G _n and G ₇ are arranged, the cathodes Kn, Kc and Kn. the grids G ₁ and G ₂ and the electrodes G ₃ . G ₁ . G ₅ , G ₆ and G _{7 are held} in the illustrated FinbauHlung by (not shown) supports made of insulating material.

For the operation of the in F i g. 1, suitable voltages are applied to the grids G ₁ and G ₂ and to the electrodes G ₃ . G ₁ . G ₅ , G _e and G ₇ placed. For example, a voltage of 0 to - 200 V is applied to the grid G ₁ , a voltage of 100 to 500 V to the grid G 2, a voltage of 10 to 25 kV to the electrodes G ₃ , G ₅ and G ₇ and a voltage of 10 to 25 kV Voltage of 0 to 4 kV across electrodes G 1 and G 2, all of these voltages being related to the cathode voltage as a reference voltage.

With the described distribution of the applied voltages, an electron lens field is generated around the axis of the electrode G., through the electrodes G ₃ , G ₄ and G ₅ , in order to form a first single lens LzM ₁ , which is indicated with dashed lines by its optical equivalent is, and an electron lens field is made around the axis of the electrode G ₆

5 6

around through the electrodes G ₅ . Because of the convexity created between them in order to form a second individual lens Lm ₁ , G 1 and G ₇ generate the plane deflection stresses. The single electron beam case with dashed lines through its optical equation system of FIG. 1 is arranged so that the valent is given. According to the invention, electron beams Bn, Bq and Br work together in the desired manner, the individual lenses Lw ₁ and Lw ₂ converge in a 5 manner or intersect at a common focusing lens arrangement Lw with an optical point which is the color off center in an opening g _p O between the lenses LhI ₁ and Lm ₁ to the selection electrode (e.g. shadow mask) Ac is so centered. form. Further, the focusing lens array are that the beams of these diverge, forming the electrode Lm jewei- G. ₃ G ₁ , G ₅ , G 1 and G, so-ligen color phosphors arranged in a corresponding arrangement. that the optical center O of the voltage Fo io to apply the same on the screen S, kussierlinsenanordnung substantially at the location is particularly important to mention that the screen S is arranged in, at which the beams B _1, B ₂ and B ₃ a large variety of sets or arrangements intersect. of vertically extending »red«, »green« and

Furthermore, the in FIG. 1 single "blue" phosphor stripes or dots Sc. Sr and electron gun is composed of an electron 15 Sb , each of the arrangements beam convergence deflector F, the shielding or each of the sets of phosphors being a color picture plate P and P '. which forms in the spacer element shown. From this it follows that the common ratio on opposite sides of the radiant point of the beam convergence corresponds to one of the color picture elements arranged on this generation system axis and axially formed, has deflecting plates Q and Q ' extending. As 20 The electron beam scanning of the surface of the shown, at a distance to the outside, opposite the screen S is done by a not shown horizon shielding plates P and P 'are arranged. Although valley and vertical deflection yoke, the horizontal and essentially flat, the deflection vertical deflection signals can be supplied so that a color image is obtained on panels Q and Q ', if necessary in the screen S known per se. Way to be slightly curved or bent outward. 25 In the case of the in F i g. 1 embodiment shown

The shielding plates P and P 'are equal to the convergence of the beams Br, Bn and B _n to the and are arranged so that the central electron beam crosses each other substantially at the optical Bc substantially without deflection between the center O by the arrangement of the respective Shielding plates P and P 'passes while the beam generators cause these convergence baffles Q and Q' to target negative charges with reference to 30 without having any of the beams optically on the plates P and P 'so that the electron Imprint aberrations. In this case it can. % vie rays Bb and Br are deflected converging. The focusing lens arrangement Lm is shown to be symmetrical around the plates P and Q as well as P 'and Q' , as is shown by the respective course thereof between optical center O. Ins- that is, the individual lenses Lm ₁ and Lm ₂ are the same, in particular a voltage which is the same as that applied to the 35 and the center point O is located in the middle of the electrodes G ₃ . G ₅ and G _{7 applied} tension. on between them. Since both shielding plates P and P ^{1 are} placed in the focusing lens arrangement Lm and formed by the two lenses Lw ₁ and Lm ₁ , a voltage that is approximately 200 to 300 V lower than that can be applied to the plates P and P by itself 'tension is laid. to the refractive power but together have a refractive power, respective baffles Q and Q '. around the same 40 which is sufficient to focus the rays sharply on the screen S to obtain potential on the screen plates P and P '. The central beam Br. Passes through the deflection voltage difference or convergence relatively flat lenses Lw ₁ and Lm ₁ along deflection voltages between the plates P 'and Q' of their common optical axis, so that P and O respectively can be achieved. As a result of this convergence, he does not experience any optical aberrations. The side deflection voltage Vc will radiate the electron beams Bb 45. Br and Bb , however, pass through parts of the Lin and Br the required convergence deflection on Lm ₁ , which are distant from the optical axis, and through parts of the lens Lm ₁ . those of

In operation, the electron beams occur Br. B _{g of} the optical axis are removed. As the rays Br

and Bb- those of the beam emitting surfaces of the Ka- and Bb at the optical center O in the middle

methods Kr. Kg and Kb go out through the grating 5 ° between the lenses Lm ₁ and Lw ₂ cross each other or

openings ^ ₁ r. g _x r, and g ^ through, to cut through, are those parts of the lenser

Signals to be brightly controlled, called "red", "green" LiH ₁ and Lm ₁ . through which the beam Bn passes

and "blue" brightness control signals denote on opposite sides of the optical axis

can be, which are located between the cathodes Kr. and in a similar way are the parts de

Kn and Kb and the first grid array G ₁ Toggle 55 lenses Lm ₁ UnULm. ₂ through which the beam Bb passes

be placed. The respective electron beam occurs, on opposite sides of the optical

are then through the arrangement of the axis shown. Therefore, although the lens Lw ₁ at de

Cathodes converges so that they are essentially beams Br and B _B optical aberrations

at the optical center O of the main lens Lm calls, through the lens Lm ₂ these rays in Betra

cross and emerge from the latter in such a way that the 60 work the same but in the opposite sense c

Rays Br and B _P , impressed away from the beam B _{G by} divergent optical aberrations, so that all dr

The mean electron beam B _G then occurs in the beam at their points of incidence on the screen

are essentially free of optical aberrations with no distraction between the two.

shield panels P and P ', since the latter is the die in Fig. 2 illustrated color image reproduction

have the same potential. The passage of the electric tube is that of FIG. 1 essentially similar

electron beam Bn between the plates P 'and Q' and that only differs from this. that the mi

of the electron beam Br between the plates P and lere electrode G ₅ 'of their focusing lens arrangement

However, O leads to deflections of convergence of the same L'm a plate-shaped part in the plane through d

fcmmS «nU limit a sarf F meet. In the case of the tube according to FIG. 2 become idlane three rays all through a * ™ "3 ™ ^ f £ d ditral beg

caused by the lenses Lm ₂ ' and Lm ₁ .

these rays are free from optical aberrations

their points of impact on the screen S.

With each of the above-described guidance

Approximate forms of the invention is the focusing lens assembly symmetrical, d. i.e. identical individual lenses are in front of and behind the optical center or the intersection of the beams. As in Fig. 6 shown, however, an inventive - • uMj ...: _ j — UKK i asymmetrical

meet. At the Konre nat “. .5- '"""" ,,, - "i., _From.. as in Fig. 6, jeaocn cmc * ..... ««. ■ * ·

all three beams by a tf ™ "Nsame B1 walls ^ b ww _Far ^g _bbil ^ _{iedergaberöhre} an asymmetric,

dazzled or diametrically limited ^ which by a _{lens arrangement L} * _{m have} which through

E. . , - j_. tr ^ t. ^^ ^^ ^^ _{before the crossroads} || _e ο the stnih-

blinded or diametrically limited. which major Electrode of the focus lens arrangement formed ^ ira

However, as in FIG. 3 8 « ^ei fj""J vie above in connection with F 'ι% ■ ben, the electron beams B ₁₁ . Bo and B "y ode are dimmed, he.sp.elswe.se dad _u reh. the electrode G ₃ with limiting openings ^ b. ^. and *, "is provided by we, Ich * ej" Igen rays enter the electrode G _{3 of} the focusing arrangement.

^^ _Kreug

len B _n . Ba and ß _B and through two. Lenses ft> », and JJ. £ _WIdet , _{which is} after the crossing point le O an- * | _{are net and so work} together that the rays experience high _aberrations

« _{And the aberrations} are the

^ f - {^ _{through the lens L} , ", is imprinted <o _{that the rays are} again free of aberrations _

their points of impact on the screen (not gc / ci

r Fok _{that the rays are} again free of aberrations _jn

n ^ ^^ _{fQr the focus} . _ao their points of impact on the screen (not gc / cigt)

lens shape must be greater than 2 . So can as m »nd _with ^ _{v existing} execution, -

F i g. 4 shown, the Focused «! enanorfnung L m ^ ^^ _{ßß ßß and ß (} . _{Kreu7en im}

a color display tube through center points "the focusing lens anor,"

the following. axially arranged electrodes .G »G ^. OWP _{ch conv iert} . _{that the} radiation generators:

G ^ G, and G _{9 are} formed. ^d ' ^ea J _m ^e ™ _ons . _S o it was arranged that the rays B _n and Pn

honem and low potential ^ g "■« mf ₍ * ™ ^ _{be emitted along} wages, which refer to au ^

to generate lens fields which LnsenLm, uno β _{de <; mediate strah) s ßf k eren} . _Jedl ,, _

around the axis of electrodes G ₁ and G ^ _mp . _{shown the invention} also U

a third lens Lw ₃ around the axis of the electrode ^ _{color image reproducer () can} be applied ^ K.

make up around. The third lens Z. i. ^ '» ^D _{which the} radiation-emitting surfaces of the cathodes A ;.

between the lenses L »», and L «>, geaig un ^ ^^ ^^ ^ _{einf £ bene dne} t _{smd de} to d ■

lih smd en hai the ^ m _{axis of the tube in essence} thchen vertical, st, o d ..

beam B 'coincident with ^ _{R "lead axis} ^^ _{wjrd and the} side beams,

_{and ßß para} u _e l _{to the} tube axis and on the opposite sides of the latter are emitted. Ferm .. ^. ^^ _{embodiment the} electrode G

^ ₁ ^ _{n reduced diameter} . the m ^ _{bhföi GiU C stretches as} shown s.

between the lenses L »», and L «>, geaig and the latter are the same. en hai die ^ m _p _

Lens Dn ₈ the optical center point α aerr lens arrangement r ^ m. at which s, chd eS ah η «λ.

Bu and ß _B cross. Hence, ™ ^eb £ _icmen

type of management according to Fig. 1. i ^^^ X strahdie through the lens Dii, hm durchtrettmaen

len Bn and B "are imprinted. voHkojti ^ e compensated by the "counterg" ωβα and J ^ aberrations. which through the lens £ "*"? J £ iemer can, as three lenses cn ™ * "£ Z arrangementL *» »« are present which he

Focus with a single Lm «« ^ ¹ _f . each a further lowered bridge

i.e. the optical Α ^^^ Shl

Rays _{h the}

_{after the}

each one

whereby the optical ^

be that the rays, ms

ß _F and B _B. to be imprinted when

n «Ze lens D», 'Jngs ^Ba ^ «S

pass through the optical axis.

above in connection rr "

Arrangement in the color b ^

F i ₂ . 4 used to d ^

beams focused on the screen S ζ _

The focusing lens assembly of the fart) ^

eaberöhre can also be more than the three m. ,

Zeisten lenses include So kaan J »:; _{Ordun (!} shown schematically, the FoKi ^ erimsen

To consist of four individual lenses / - », ^" ^ - _the D ^, where d, eLmsen L ^ unü ^

optical center or which are arranged, while ^d «^ f ^ seen behind the center O. ^ m rays from the cathodes A". Ka screen (not shown), arranged J · «^ _z Shl B and hd lenses

₄₅

^ ₁ ^ _{n reduced diameter} . de ^ _{cup-shaped GiUer Ca extends} . _WI e shown that. if the in connection with F ι g. 1 described. There is a voltage distribution, an electron _{lens- {dd} ^. ^^ _dem ^^ _{G d of} the electrode G.,

_{is generated} . _u m to form an auxiliary lens L. as π. _dashed lines indicated by which <£ rays B _n and β «are converged so that si. _{each other and the} middle ray Ba im wesen l.ch.n optical centers? the Fokussierlin>_c; -

^^. _{0 and L} * _nu _ _gebi i _de t is. In this case »>, ■! ■ - _h kussier lens arrangement Um can be asymmetrical, d I ^ _{the lens} Um ... which is arranged after the optical center point. can be provided so that o _P - ^^ _{Aberratjonen the} side beams 5, and B, _{on AEGT the same and s are} t _g egenge, egg ₇ i _{of the optical Summg Abert} ation smd. what

_the rays through the auxiliary lens L. and the lens L m ^^^ _wgkhe ^ _{d £ m Qptischen Mltt} el _pun kt O an

_{Furthermore, in this} embodiment, _{the focusing lens arrangement Vm} symmetrically ser ^ ^ ^ ^ _n ^ _{and Lef? ji k the same}

in which case the lens Um with its optical _{center 0} essentially at the intersection: ^ _{def drd StraWen however} , _kkmen A

_which it can be arranged where

the

^ _{def drd StraWen however} , _kkmen A

Screen (not shown), arranged J · «^ _{z and 6 stood from which} it can be arranged, causing the rays Bn and S«. through the lenses, ^ ^ _{Ahemüonen of the rays Br and ßß} korng.e Dn ₁ 'impressed optical aberraj * ^. ^ ^ are _{the through the} auxiliary lens L, heremgebrac ik or correction ο ^ ^

Dn ₁ 'impressed optical counter-effect or correction ο ^. ^ _{Will be experienced} de-sea-attached optical λ.

1 sheet of drawings

209 508 / Ξ

Claims (6)

Patent claims: 1. Color display tube with a single electron gun for generating several electron beams, with a screen that carries arrangements of different color phosphors and is acted upon by the electron beams to excite the associated phosphors of the arrangements, with an electrostatic focusing lens arrangement for focusing the electron beams on the screen and with a device for aligning the electron beams so that they form acute angles to one another and intersect at a point within the focusing lens arrangement, characterized in that the focusing lens arrangement (Un) is formed from several individual lenses (Lm ₁ , Lm ₁ ) , which are arranged one behind the other along the tubular lizard and each have several electrodes (G, with G ₇ ) at different electrical potentials, so that at least one lens (Lm ₁ ) of the individual lenses between the intersection points (O) of the electron beams (B _B. B >;. Bn) and the Single electron gun (G ₁ , G ₂ ) is arranged and that at least one other lens (Lm ₂ ) of the individual lenses between the intersection and the screen (S) is arranged so that the one and the other lens extend Rays distant from the tube axis are exposed to opposite aberrations through one and the other lens (Fig. 1). 2. Color display tube according to claim 1, characterized in that one electrode (G'5) of the electrodes is arranged at the intersection (O) of the electron beams and has a limited opening. in order to limit the diameter of the electron beams (Bn, Bo. Bn) passing through and thus to generate sharp light spots on the screen (5) (FIG. 2). 3. Color display tube according to claim 1, characterized in that the one lens (Lm ₁ ) and the other lens (Lm ₁ ) generate identical electrical fields which are arranged symmetrically to the point of intersection (O) of the electron beams around the rays remote from the tube axis to expose the same aberrations, but acting in the opposite sense (FIG. 1). 4. Color display tube according to claim 1, characterized in that between the Krcuzungsstelle (O) of the Elcktronenstrahl (Bh. B _(; , Bn) and the single electron gun {Kn. Ki ;. Ku) on the one hand and between the Kreuzungsstellc and the screen ( S) on the other hand, a different number of individual lenses (Lm ₁ : Im _2. Im ₁ ') of the focusing lens arrangement (L ¹ IU) is arranged (FIG. 6). 5. Farbbildw icdcrgaberöhrc according to claim 1, characterized in that the single-electron beam generating system has individual beam sources (Kn, AV ,. Kn) . that the device for aligning the electron beams (Bn. Ba. Bn) to the point of intersection (O) carries the individual beam sources, the beams emitted by them converge to the point of intersection (Fig. I). 6. color picture display tube according to claim 1): idurch that the emitted from the simple electron beam generation system (Bb, Ba, B _R ) are separated from each other, that the device for aligning the electron beams to the intersection (O) has a HiIFs lens (Ls) , which is located between the single electron gun and the focusing lens arrangement (L ³ m) and allows the electron beams to converge to the point of intersection, the off-axis rays passing through the auxiliary lens being exposed to optical aberrations through the auxiliary lens and the other lens (Lhtu) being exposed to the focusing lens arrangement these off-axis rays apply aberrations which are opposite in size to the sum of the aberrations caused by the auxiliary lens and the one lens (L ₅ W ₁ ) (FIG. 7).