DE1918913A1 - Convergence deflection device for multi-beam color picture tubes with a single electron gun - Google Patents

Description

Convergence deflection device for multi-beam color picture tube with a single electron gun

The invention relates generally to color picture tubes of the multi-beam type with a single electron gun, especially tubes, in which the multiple beams are guided through the optical center of a common electron lens, which the Rays focused on the fluorescent screen "

In multi-beam color picture tubes with a single electron gun, as listed above and as described, for example, in a pending US patent application by the applicant (Ser _e No. 697 "414 of January 12, 1968), three with a beam generating device or cathode group electron beams guided at a mutual lateral distance in a common, essentially horizontal plane, the central beam coinciding with the optical axis of the single electronic collecting lens and the two outer or lateral beams being brought to convergence so that they

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hit telstrahl in the optical center of the lens and then are guided from this on tracks that diverge from the optical axis. Along these diverging paths, associated beam convergence-inducing pairs of deflector plates are provided which form a convergence deflector and to the voltages which generate electric fields, which deflect the diverging rays laterally in a substantially horizontal plane and cause all rays to strike a common spot on the apertured Beam selection aperture (shadow mask) are brought together, which is assigned to the fluorescent screen. Between the con vergence deflection device and <fem fluorescent screen is also a main deflection yoke provided according to it supplied Sweep signals for horizontal and vertical deflection generate horizontal and vertical magnetic deflection fields, which act on all rays and cause them to scan the luminescent screen in predetermined grid figures. Because the rays are spaced apart in the horizontal direction and during their passage through the horizontal deflection field do not run parallel, the distances that the side rays cover in such a field are greater or smaller than the distance that the central ray travels in the field, provided that the rays follow one or the other Side of the screen, if there is a uniform field strength in the horizontal deflection field the side ray that covers a greater distance in this field more deflected than the side ray that is in this Field travels a shorter distance, and there is poor convergence of the rays. But even if the If the field strength in the horizontal deflection field is not uniform, a deficient convergence can only be achieved with it then avoid when the rays are deflected relative to the two sides of the screen so that this deflection path maintains the middle between the highest and the lowest point of the screen, i.e. if the common plane of the rays passing through the horizontal deflection field horizontally

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is directed, with other places essentially perpendicular to the vertical lines of the magnetic flux of the horizontal Deflection field. However, if the common plane of the rays passing through the horizontal deflection field is against the horizontal is inclined, i.e. when the vertical deflection field deflects the rays so that in cooperation with the horizontal deflection field, the rays are directed into an upper or lower corner of the screen, the larger Difference between the distances covered by the side rays in the horizontal deflection field still water and can ultimately no longer be compensated for by means of a non-uniform field strength distribution in the horizontal deflection field will. Therefore, the raster of the side rays can assume shapes that are opposite to the raster shape of the central ray are recorded.

The invention is therefore intended to provide a multi-beam color picture tube with a simple electron gun, and that of The grids supplied to the various rays of the color picture tube should not show any distortion in relation to one another mutual drawings should also be made with the help of a certain construction of the convergence deflection device can be turned off.

In one embodiment of the invention, those are described Distortions of the side beam grid compared to the center beam grid prevented that the distances between the pair-wise matching plates of the convergence deflection device can be varied appropriately in the direction perpendicular to the common beam exit plane, whereby in corresponding Extent the strength of the electric fields between these plates that cause the side rays to converge be distracted, is varied.

The properties mentioned above and other features and advantages of the invention will become apparent from the following detailed Description of an embodiment of the invention and the

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associated drawings showing:

Fig. 1 is a schematic horizontal section in the plane the axis of a multi-beam color picture tube suitable for the application of the invention with a single Electron gun;

Fig. 2 is a schematic view which will be explained in more detail later;

Fig. 3 is a schematic view of the possible relative Distortions of the grids of the various rays, seen from the observer side of the screen, to be eliminated according to the invention;

4 shows a schematic sectional drawing through the convergence deflection device a color picture tube in a first embodiment of the invention;

FIGS. 5 to 8 are views of others corresponding to FIG. 4 Training opportunities of the invention.

A multi-beam color picture tube equipped with a single electron gun, in which the concept of the invention can be implemented, has, according to FIG. on which the usual groups of color phosphors S _R , S _G and S _ß are arranged and in front of which a shadow mask G _{p is} provided. In the neck part N an electron gun A is accommodated, which has cathodes K _R , Kp and Kg, each of which consists of a beam generating source, the beam generating surfaces of which, as shown, lie in a plane which runs essentially perpendicular to the axis of the electron gun A. . In the case of the drawn

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guide shape, the beam generating surfaces are arranged on a straight line, so that the rays emerging from the surfaces B _R ; B _fi and B _{ß run} in a substantially horizontal plane which includes the axis of the electron gun, the central beam B _{ß coinciding} with this axis. A grid G-mounted at a distance from the beam-generating surfaces of the cathodes K _R , K _G and K _{ß has openings g-R} , g _1G and gj, which are aligned with the associated beam-generating cathode surfaces. At a distance from the first grid G ₁ , a common grid G _{2 is} attached, which has openings g _2R , g _2G ^and g _2B which are aligned with the corresponding openings of the first grid G-. Further offset in the axial direction with respect to the common grid G2 are tubular grids or electrodes G ,, G * and G ₅ with open ends, the cathodes K _R , K _ß and K _ß , the grids G and G ₂ and the electrodes G. ,, G ^ and Gr are held in a suitable manner in the arrangement shown.

To operate the electron gun according to FIG. 1, the grids G-. and G ₂ and the electrodes G ₃ , G ^ and G ^ are supplied with suitable voltages. For example, the grid G- receives a voltage between 0 and 400 V, the grid G ₂ a voltage between 0 and 500 V, the electrodes G, and Gr a voltage between 13 and 20 kV and the electrode G ^ a voltage between 0 and 400 V, all of the voltages mentioned referring to the cathode voltage as a reference value. Accordingly, the voltage distribution between the respective electrodes and cathodes and their respective lengths and diameters can essentially correspond to those of a single-potential single-beam electron gun which consists of a single cathode and a first and a second grid with a single opening.

In the case of the voltage distribution given above, an electron _{lens field is built up between the grid G 2} and the electrode G ₃ , so that an auxiliary lens L ¹ is produced, which is shown in dashed lines

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is drawn, and an electron lens field is also formed around the axis of the electrode G ^ by the electrodes G ₃ , G4 and G ₅ , so that a main lens L is formed, which is also shown in dashed lines. In the usual operating mode as an electron gun bias voltages can of 100 V, OV, 300 V, 20 kV, 200 V and 20 V to the cathode Kp, K "and K _Q, the first and zwaten grid G. and G ₂ and the electrodes G ₃ , G ^ and G5 are used.

On the electron gun A according to FIG. 1, a convergence deflection device F is also provided, which has inner shielding plates P and P ¹ which, as shown, are attached on both sides of the axis of the electron gun at a distance therefrom, as well as in the axial direction extending deflection plates Q and Q ¹ , which, as shown, ^{face the shielding plates P and P 1} at a distance on the outside. The deflection plates Q and Q ¹ run in a straight line, but they can also be designed to be somewhat curved or bent outwards in a manner known per se.

The shielding plates P and P ¹ are equally charged and arranged so that the central electron beam B _G passes between them practically undeflected, while the deflection plates Q and Q * ^{are negatively charged with respect to the plates P and P 1} , so that the electron beams B _ß and B _f are deflected as they pass between the plates P and Q or P ^f and Q ¹ in the manner shown to converge. In particular, a _{voltage V p} equal to the voltage applied _{to electrode G 5} can be applied to the two shielding ^{plates P and P 1} , while a voltage V », which is approximately 200 to 300 V below voltage V _p, is applied to the plates 0 and Q 'is placed so that the plates P and P ^{1 are} at the same potential and a deflection voltage difference or convergence-deflection voltage Vp is between the plates P ¹ and Q ¹ and the plates P and Q, the convergence then Deflection voltage V _c required for converging electron beams B _ß and B _R

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Distraction supplies.

When working the tube, the outgoing electron _ß of the beam-generating surfaces of the cathodes K _R, K "and K B _R, B p and B run _ß by the associated grid openings g _1R" gjg and gi _R "which by red, green and Blau-Heils control signals are brightly controlled, which are placed between the cathodes and the first grid G-. The electron beams then pass through the common auxiliary lens L ¹ and cross each other in the center of the main lens L. After that, the central electron beam B “runs practically undeflected between the shielding plates Γ and P ¹ because they have the same potential. The electron beams B _ß or B _R passing through between the plates P 'and Q ¹ or between the plates P and Q, on the other hand, are deflected to converge because the convergence-deflection voltage V _Q prevails between the plates, and the entire system according to FIG , I is designed so that the electron beams B _ß , B ~ and B _R converge as required or cross each other at a point which is in an opening of the shadow mask G _p , and from there diverge and onto the respective associated color phosphors of a color phosphor group the screen S fall. The fluorescent colored screen S consists of a large number of groups of vertically running colored phosphor strips or spots S _R , S _G and S _ß in "red", "green" or "blue", each representing a color picture element. The common point of incidence of the converging rays corresponds to such a color picture element.

The voltage V _p can also be supplied to the lens electrodes G ₃ and G ₅ and the screen S as an anode voltage, as well as to the shadow mask Gp. The scanning of the surface of the colored fluorescent screen can take place in the usual way, for example by applying horizontal and vertical sweep signals to an arrangement (main deflection yoke D) shown in dashed lines, with which horizontal and vertical deflection fields are generated,

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which cause the beams to scan the screen and produce a color image thereon. As with the described Arrange the respective electron beams to focus through the center of the main lens L of the electron gun A are the spots created by the rays hitting the fluorescent screen essentially free from disturbances caused by coma and / or Astigmatism errors of the main lens are brought about can; this improves the resolution of the color image.

In the color picture tube shown in Fig. 1, the plates P and P ¹ and the plates Q and Q 'are drawn as flat surfaces which are parallel to each other, so that the electrical generated ^{between the plates P and Q and the plates P 1 and Q *} Fields in these areas are essentially uniform, ie in the direction perpendicular to the common horizontal plane of the rays B _fi , B ,, and B-. If, therefore, the rays from the vertical deflection field of the yoke D are guided in the vertical direction-aigeienEt and £ ü : äMifi @ ri ^ nodSrtraf · ^ ^ lower section of the fluorescent screen S and the vertical deflection field displaces the rays vertically within the convergence deflector F , the deflecting effects of the fields between the plates P and Q or the plates P ¹ and Q ¹ on the beams B _ß and B _{R are} practically not changed. If, on the other hand, as indicated in FIG. 2, the horizontal deflection field of the yoke D deflects the rays to the left side of the screen (as seen from the viewer), ie downwards in the representation according to FIG. 2, the side rays Bg and B _R pass through this Horizontal deflection field distances that are larger or smaller than the distance covered by the central beam Bg in the horizontal deflection field. If, conversely, the horizontal deflection field of the yoke D deflects the rays to the right side of the screen (as seen from the viewer), the _{distances traversed by the rays B ß} and B _R in the horizontal deflection field are shorter or longer than the distance that the central ray B _G in this Field. Because

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of the above-mentioned differences in the path of the rays in the horizontal deflection field when the rays are deflected to one or the other side of the screen S, the grids of rays B _ß and B _R would be offset to the left or right with respect to the grid "of ray B _G (respectively seen from the direction of the observer looking at the screen) .If the horizontal deflection field of the yoke D receives a non-uniform distribution of the field strength, e.g. if the sides receive a higher field strength than the center, the identical raster distortions can be compensated for as long as the common beam plane essentially runs horizontally, that is, as long as the rays move essentially in an area midway between the upper and the lower edge of the screen. However, if the horizontal deflection field of the yoke Yoke D deflects the rays in the vertical direction, so that the common beam plane is inclined with respect to the horizontal and the rays get into a corner of the screen, the differences between the distances traversed by the rays in the horizontal deflection field increase compared to the differences in the distances covered in the field when the common plane is horizontal, so that the aforementioned non-uniform distribution of the field strength in the horizontal deflection field of the yoke D is insufficient to avoid distortions of the grid of the beams B _ß and B _R with respect to the grid of the beam B _r .

If one assumes a rectangular shape L _fi (FIG. 3) for the grid of the central _{beam B 0 , the grid L 1 of} the beam B ~ is so drawn (as seen from the screen viewer) that its sides are convex to the right, while the grid L _{R of} the ray B _{R is drawn in the} opposite direction, ie convex to the left.

According to the invention, such distortions of _{rasters of the side rays B ß} and B _R compared to the raster of the central

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91 891 3

Beam B ^ by suitable variation of the distances between the plates P and Q or P * and Q ¹ in the direction perpendicular to the common exit plane of the beams, for example in the vertical direction in the tube of FIG. 1, avoided. For example, in the embodiment according to FIG. 4, the plates P and P * are flat, while the plates Q and Q ¹ are concave in the horizontal or in the direction transverse to the plates, whereby the distances between the plates P and Q or respectively The plates P ¹ and Q ¹ are kept relatively small in the area of the horizontal plane 21 enclosing the tube axis and become increasingly larger up and down in the direction of the vertical plane 22 from the horizontal plane 21, which is also the exit plane of all rays.

Since the convergence deflection device F is arranged near the main deflection yoke D (FIG. 1), the vertical deflection field of the yoke D obviously extends into the device F and thereby affects the vertical position of the beams Bg, Bg and B _R when they are Run through facility F. If now the horizontal and vertical deflection fields of the yoke D control the rays in a corner of the screen, the vertical deflection field of the yoke D displaces the rays B _R , B _ß and Β «from the plane 21 in the deflector F either vertically upwards or vertically below. Because of the greater distance between the plates P.jind Q and the plates P 'and Q1 in these positions of the beams B ¹ _{and B R} , the parts of the electric fields acting on the beams exert less influence, which at the same time deflects the convergence applied to the rays B ″ and B _R is decreased. Therefore, if the beams are deflected vertically and horizontally by the yoke D into the upper or lower left corner of the screen (viewed from the observer's side), the left deflection of the beam Bg in the field between the plates P and Q is reduced and the right deflection of the beam

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B _R in the field between the plates P 'and Q' also reduced, whereby the left sides, the grid L _ß and L _R (Fig. 3) comes in a coincident position with the left side of the grid L ~. Accordingly by vertical and horizontal deflection of the yoke in the upper or lower right corner of the screen (Fig. 3), the left deflection of the beam B _g or · the right Eblen Kung the beam B _R by the fields between the plates P and Q respectively, "the Plates P ^y and Q * are reduced, as a result of which the right-hand sides of the grid L "and L _{R come} into a coincident position with the right-hand side of the grid L". The distortion of the grids Lg and L _R with respect to the grid L _fi can thus be effectively avoided by appropriately positioning the convergence deflection device F with respect to the yoke D and by the shape of the plates Q and Q ¹ .

As can be seen from FIGS. 5 and 7, the above-mentioned can be

Q and Q * and outwardly curved inner panels P and P '(Fig. 5) are used, or if outer panels Q and Q' are provided, which are curved inward, and inner, outwardly curved panels P and P '( Fig. 7). With these modifications, the distance between the plates P and Q or the plates P ¹ and Q ^{1 changes} from a minimum value in the horizontal plane including the tube axis to maximum values at the upper and lower plate edges, with the electric field strength between the plates P and Q or the plates P 'and Q ^{1 is changed} in the opposite sense. Since the plates P and P * are at the same potential, there is no electric field between them and the variable distance between the plates P and P 'in FIGS. 5 and 7 therefore _{does not affect the beam B Q} when it is deflected vertically .

So far it was assumed that the raster distortions at Lg and L _R compared to the raster L ^, which it compensates

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applies, correspond to the illustration in FIG. 3. However, it can also happen, for example due to the special shape of the horizontal deflection field generated by the yoke D, that the grid of the beam B _{ß has} the shape L _R according to FIG. 3, while the grid generated by the beam Bp has the shape Lj , according to Fig. 3 has. In this case, the plates P and Q or the plates P ¹ and Q ^{1 are given} a shape in which the distance between the plates has its maximum value in the horizontal plane containing the tube axis and from there iji in the vertical direction, ie in the direction perpendicular to the common beam exit plane, is continuously smaller. In order to achieve such spacing variations between the plates, the plates P and P ¹ can be made flat, while the plates Q and O ¹ are curved outwards (FIG. 6) or the plates P and P ¹ are bent inwards and the plates 0 and Q ¹ have an outward curvature (Fig. 8).

In the embodiments of the invention described so far, the convergence deflection device F consists of a single pair of plates P and Q or P ¹ and Q ¹ , which act on one of the beams B _β and B _R and converge the respectively assigned beam bring with the central beam B _G. However, the invention can also be applied to other color picture tubes, for example to the color picture tube described in the pending USA application Ser. No. 718.738 of the applicant of April 4, 1968, in which two pairs of deflection plates act one after the other on the paths of the rays diverging after exiting the converging lens, the first pair of plates including an electric field through which the beam passing through is even further from the tube axis is pivoted away, while the second pair of plates includes a field through which the beam is deflected so that it is directed towards the other beams to converge with them. The specified arrangement makes it possible to enlarge the angles of incidence of the side rays Bg and B _R on the shadow mask G _p , as a result of which

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BATH ORIGINAL

the distance between the shadow mask and the luminescent screen decrease and the exact alignment and. Can simplify mounting the shadow mask opposite or on the screen. If, as described, _{two pairs of deflection plates act successively on each side beam B ß} and B _R , according to the invention, the distance between the plates is varied in the direction perpendicular to the common beam exit plane on one of the two plate pairs, preferably on the plate pair closest to the main deflection yoke to prevent the raster of the relevant beam from being distorted.

The invention is not intended to apply to the exemplary embodiments described be limited, and in the professional world numerous modification options are known that can be used, without going beyond the scope of the invention.

I-1

Claims;

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Claims (1)

Patent claims; Multi-beam color picture tube with a single electron gun, with a common exit plane central electron beam and two side beams, all through the optical center of an electron lens run, from which the rays are focused on a color screen, the central ray along the lens whose optical axis leaves, while the two side rays emerge from the lens on paths that are in opposite directions Move direction away from the center beam with an electrostatic convergence deflector, which are arranged along the diverging beam paths at a distance from one another and applied to the voltages are to generate electric fields by which the beams passing through the pairs of plates are deflected substantially in the said common plane, so that they meet at a common point on the central ray, and with a main deflection yoke, through the the rays are deflectable in the direction of the common plane and perpendicular to it, around the luminescent screen by the rays to be scanned, characterized by d, the convergence deflector (F) is disposed relative to the yoke (D) as ₉ that the on from this generated, for deflecting the beam (B) vertically = 'right to the common plane (21) suitable field the beams (B) acts within the convergence deflector (F), and that the distance between the plates of the plate pairs (P, Q; P ¹ , O ¹ ) is variable in the direction perpendicular to the common plane (21) _g §o that dip strength © 009841/1084 BAD ORfGShJAL of the associated field is correspondingly variable in order to avoid all distortions of the grid (L _R , L ") of the side beams (B _R , B _n ) compared to the grid (Lg) of the central beam (B ^). 2, multi-beam color picture tube according to claim 1, characterized in that the distance between the plates of each pair (P ₁ Q; P ¹ , Q ¹ ) progressively from a minimum value in the common plane (21) to a maximum value in the opposite , edges of the plates (P, P ¹ , Q, Q ') remote from the plane (21). Multi-beam color picture tube according to Claim 2, characterized in that the inner plate (P; P ¹ ) of each plate pair (Pt Q » ^pl » Q ') * ^{since it is} closest to the central ray (Bg) is flat, while the other plate (Q; Q *) of the respective pair is convexly curved ^{against the inner plate (P; P 1).} Multi-beam color picture tube according to Claim 2, characterized in that the inner plate (P; P ¹ ) of each plate pair (P, Q; P ¹ , Q ¹ ) which is closest to the central beam (Bg) faces the other plate (Q ; Q ¹ ) of the respective pair is convex, while the other plate (Q; Q ¹ ) is flat. 5. Multi-beam color picture tube according to claim 2, characterized in that the plates of each pair (P, Q; P ^f , Q ¹ ) are mutually convexly curved. BATH 809845/1064 6, multi-beam color picture tube according to claim 1, characterized in that the distance between the plates of each plate pair (P, Q; P ¹ , Q *) progressively from a maximum value in the common plane (21) to a minimum value on the opposite one , edges of the plates (P, P ¹ , Q, Q ^f ) removed from the plane (21). 7. multi-beam color picture tube according to claim 6, characterized in that? the inner plate (P; P ^f ) of each pair of plates (P, Q; P ¹ , Q *) which is closest to the central ray (B ,,) is flat, while the other plate (Q; Q ¹ ) of the respective pair against the inner plate (P; P ¹ ) is concave. 8. Multi-beam color picture tube according to claim 6, characterized in that the plates of each pair (P, Qj P ¹ , Q ¹ ) are concave towards one another. The patent attorney SÖ9845 / 106