DE2018943A1 - CATHODE RAY TUBE - Google Patents

Description

This invention relates generally to cathode ray or color picture tubes of the single cathode ray generator type, and more particularly Tubes of the type in which the plurality of beams pass essentially through the optical center of a common Electron lens are passed through which the rays are focused on the color screen.

In the case of color picture tubes with a single beam generator and several beams of the type on which the In accordance with the invention, for example of the type described in US Pat. No. 3,448,316, multiple electron beams are emitted or generated by a beam-generating cathode assembly and converges on them each other at a point between the cathode assembly and cross or overlap the color shade on the the rays strike, and a single · electron focus β ierlinsezii »focusing all rays on the screen

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is arranged in such a way that the optical center is essentially at the stable at which the rays are located Overlapping, reducing coma and spherical aberrations, which are communicated to the rays through the focusing lens, can be reduced significantly. When the rays are converged so that they are substantially at the optical center of the focusing lens overcut, step at least certain of the rays emanate from the lens along diverging paths and pairs of convergence baffles can be arranged along these diverging paths to which voltages are applied to reduce the deflect diverging rays in such directions that all rays at a common point on the beam selection grating or on the mask, that or the color screen is assigned, converge or the diverging beams are allowed to be on the beam selection grating or on the mask hit at a distance from each other, appropriate delays are imparted to the color signals by which the beams are modulated so that a match of the images produced on the screen is obtained. In any case, the rays act on the magnetic fields, which result from the supply of horizontal and Vertical deflection signals result to the corresponding coils of a deflection yoke, thereby causing the beams to scan the screen with the desired button.

In a color picture tube having a single beam generator and more of the type described above fcfchodenstrahlen the only Elektronenfokussierlinse has a sufficiently high capacity have _f fokuesieren on the screen, the beams and they must, therefore, an optically equivalent lens "it strong curvatures, ie, small radii of curvature at their Fleeing corresponds to »which is why the rays» even if they pass through the central part of the single electron focusing lens of high refractive power, are

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know optical aberrations are communicated. Further when the rays are converged so that they meet each other substantially at the optical center of the Cross or intersect electron folcussing lens, which convergence is done by means of an auxiliary line, the one between the beam generator and the focusing lens is arranged, the rays passing through the auxiliary lens at considerable distances from the center of the latter pass through, certain optical aberrations are communicated by the auxiliary line, which may be of low refractive power in order to make these aberrations as small as possible to keep.

The object of the invention is therefore to create a cathode ray or picture tube of the type described, in which optical aberrations of the rays when focusing on the color screen can be further reduced.

Furthermore, the invention is to provide a color picture tube of the type described, in which the Beams communicated by "optical aberrations" that they are converged to intersect at a point between the beam generator and the screen, or fully compensated when the beams are focused on the screen Getting corrected.

IT

Likewise, the invention is to provide a color picture tube of the type described, in which the diametrical size of the rays at the point where they intersect with each other is so limited that the rays apply the screen at sharply delimited points.

According to a feature of the invention, the multiple rays of a color picture tube with a single cathode ray generator and multiple cathode rays on the Screen focused through an electron focusing lens,

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which is formed by several lens elements which are arranged in an axial sequence and an optical center inside the focusing lens and are arranged substantially at the point at which the rays intersect. If the focusing lens is formed by several lens elements, such as evahnt, each of the lens elements can be proportionate be flat or have a low refractive power to get a combined refractive power that sufficient to focus the rays on the screen. Furthermore, the lens elements, which are arranged before or after the point at which the rays intersect, can communicate optical aberrations to the rays, which cancel each other out or completely free the rays from optical aberrations on the screen, even if the rays are made to overlap through an auxiliary lens "

According to a further feature of the invention, an electron lens field is produced for each of the lens elements of the focusing lens by means of a plurality of electrodes of different ones electrical potentials generated, with one of the electrodes arranged at the optical center of the focusing lens is and has a restriction opening through which all rays pass through to a diaphragm to limit the diametrical size of the rays.

The foregoing and other objects, features, and advantages of the invention emerge from the following details Description of exemplary embodiments thereof in conjunction with the accompanying drawings demonstrate:

Fig. 1 is a schematic view in section according to a

horizontal plane through the axis of a color image * -

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tube with a single beam generator and multiple beams according to an embodiment of the Invention;

FIG. 2 is a view similar to FIG. 1, but which

shows a modification of the color picture tube according to the invention;

Fig. 3 is a partial view in schematic representation and in section, which shows a further modification of the Embodiment according to Fig. 1 shows j

Figure H is a view similar to Figure 1, but again a further embodiment of the invention and

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

The color picture tube shown in Fig. 1 with a single beam generator anda plurality of rays "to which the invention is applied may a glass flask (not shown) with einem.Hals and a funnel up λ wise, the latter from the neck to a color screen S extends, which is provided with the usual arrangements of color phosphors and a beam selection grid AG. Within the neck is a single electron gun with cathodes Kj ,, Kq and Kg, each of which is formed by a beam generation source whose beam generation surfaces are arranged in the manner shown, so dft the respective beams B _R , B _Q and B _ß , the are imitated by them, are directed in an essentially horizontal plane which contains the axis of the beam generator, wherein the central beam B _Q coincides with this axis and the side beams B _R and B ₃ converge to the axis.

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A first grid arrangement G ₁ of first grids G _1R , G _1Q and G _1B is located at a distance from the beam generating surfaces of the cathodes K _R , K _Q and K _ß and is formed with openings gi _R i gjg and g _1B , which are with the respective cathode emitter generating surfaces are in alignment. A common grid G »is located at a distance from the first grids and is formed with openings g _2R » g _2G and g _2ß which are in alignment with the respective openings of the first grid. Open-ended tubular grids or electrodes G ₃ , G ^, G ₅ , Gg or «G ₇ are arranged successively in the axial direction _{away from the common grid G 2} , the cathodes K _R , K _Q and K _ß , the grids G ₁ and G ₂ and the electrodes G ₃ , G ^, G _g , G _g and G _{7 are held} in the assembled positions shown by suitable supports, not shown, of insulating material.

For the operation of the electron gun shown in FIG. 1, suitable voltages are applied to the grids G ₁ and G ₂ and to the electrodes G ₃ , G ₁ ^, G ₅ , G and G ₇ . For example, a voltage of 0 to minus 200 V is applied to the grid G ₁ , a voltage of 100 to 500 volts to the grid G ₂ , a voltage of 10 to 25 kV to the electrodes G ₃ , Gg and G ₇ and one Voltage from 0 to U kV to electrodes G ^ and G ₆ , all of these voltages being based on the cathode voltage as the reference voltage.

In the above-described distribution of the applied voltages, an electron lens field is generated around the axis of the electrode G ^ by the electrodes G ₃ , G ₁ ^ and G ₅ to form a first lens element Lm ₁ , which is indicated with dashed lines by its optical equivalent is, and an electron lens field is generated around the axis of the electrode Gg by the electrodes G ₅₁ Gg

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and G _{7 is} generated to form a second lens element Lm ₂ , also indicated in dashed lines by its optical equivalent. Therefore, according to the invention, the lens elements Lm. And Lm ₂ cooperate to form a main focusing lens Lm with an optical center 0 between the lens elements Lm 1 and Lm ₂ . _{Further, the electrodes G 3} , G ₁₄ , G ₅ , Gg and G ₇ forming the main focusing lens Lm are arranged so that the optical center of the main focusing lens is located substantially at the position where the beams B ₁ , B ₂ and B ₃ overlap each other. |

Furthermore, the electron gun shown in Fig. 1 comprises an electron beam convergence deflector F, the shielding plates P and P ¹ , which are arranged in the illustrated spacing relationship on opposite sides of the gun axis, and axÄL extending deflector plates Q and Q ¹ , which, as shown, has ^{The shielding plates P and P 1} are arranged at a distance outwardly opposite the shielding plates P and P 1. Although shown essentially straight, the deflecting plates Q and Q * can optionally be somewhat curved or bent outward in a manner known per se.

The shielding plates P and P 'are equally charged and are arranged so that the central electron beam B _Q passes between the shielding ^{plates P and P 1 with} essentially no deflection, while the deflecting plates Q and Q ^{1 have} negative charges with respect to the plates P and P * so that the electron beams B _ß and B _{R are} deflected in a convergent manner, as shown by the respective course of the same between the plates P and Q as well as P ¹ and Q ^1. In particular, a voltage equal to that at the electrodes G ₃ , G ₅ and G _{7 applied} voltage, are applied to both shielding plates P and P 'and one

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Voltage which is about 200 to 300 volts lower than the ^{voltage applied to the plates P and P 1} can be applied to the respective deflector plates Q and Q ¹ to obtain the same potential on the shield plates P and P 'and the application of a Deflection voltage difference or of convergence deflection voltages between the plates P * and Q ¹ or P and Q to achieve. This convergence deflection voltage V ^ is of course _{communicated to the electron beams B ß} and B _R the required convergence deflection.

In operation, the electron beams B _R , Bg and B _ß , which emanate from the beam generating _{surfaces of the cathodes K R} , K and K _ß , pass through the grid openings g _1R , g _1G and g _lß in order to be brightly controlled by signals which may be referred to as "red", "green" and "blue" brightness control signals which are applied between the aforesaid cathodes and the first grid arrangement G ^. The respective electron beams are then converged by the illustrated arrangement of the cathodes so that they cross each other essentially at the optical center O of the main lens L and emerge from the latter so that the beams B _R and Bq diverge from the beam Bg. The mean electron beam Bg then passes between the shielding plates P and P * essentially without deflection, since the latter have the same potential. The passage of the electron beam Bg between the plates P * and Q * and the electron beam Bp between the plates P and However Q performs the same because of the aischen them applied Konvergenzablenkspannungen and the system of Figure to convergence distractions. 1 is arranged such that the electron Bg, B _g, and B _R converge in the desired manner or intersect at a common point each other, in an opening g of the beam selection grid or the mask A " is centered in such a way that the beams diverge from it, around the respective color phosphors of a corresponding arrangement of the same on the screen S

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to apply. In particular, it should be noted that the color phosphor screen S is composed of a wide variety of sets or arrays of vertically extending "red ¹¹ ," green "and" blue "phosphor stripes or dots S _R , S _Q and Sg, each of which Arrangements or each of the sets of color phosphors form a color picture element, from which it follows that the common point of beam convergence corresponds to one of the color picture elements thus formed.

The electron beam scanning the surface of the screen * Farbphosphor- done by a not shown horizontal and vertical deflection yoke, the horizontal and vertical deflection signals are fed, so that a color image is obtained on the color screen.

In the construction shown in Fig. 1, the convergence of the beams B _R , B _Q and B _β to intersect with each other is effected essentially at the optical center 0 by the arrangement of the respective beam generators, so that this convergence is achieved without any of the beams to communicate optical aberrations »In this case, as shown, the main focusing lens Lm around the optical |

Be symmetrical around the center 0, ie the lens elements Lm. And Lm ₂ are equal and the center 0 is in the middle between them. Since the main focusing lens is _{formed by the two lens elements LH 1} and Lm ₂ , each of these lens elements can have a relatively low refractive power and still have a combined effect that is sufficient to focus the rays sharply on the screen S. The central beam B _Q passes through the relatively flat lens elements Lm 1 and Lm ₂ along their common optical axis, so that no optical aberrations are communicated to it. However, the side _{rays B R and} Bg pass through parts of the Lineenel -

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meivts Lm ^ through which are located at a distance from the optical axis, as well as through parts of the lens element Lm ₂ * which are located at a distance from the optical axis. Since the rays B _R and B "cross or intersect at the optical center in the middle between the lens elements Lm. And Lm ₂ , those parts of the lens elements Lm ₁ and Lm ₂ through which the ray B _R passes are naturally located on opposite sides of the optical axis, and similarly, the portions of the lens elements Lm ^ and Lm ₂ through which the beam B _β passes are on opposite sides of the optical axis. Therefore, although the lens element Lm. Notifies the rays B _R and Β "optical aberrations, _{equal and opposite optical aberrations are communicated to these rays by the lens element Lm 2} so that all three rays are free from optical aberrations at their points of incidence on the screen S »

The color picture tube according to the invention shown in FIG. 2 is essentially similar to that described in connection with FIG and the diametrical Grosse each of the beams B ^, Bq, and B ₃ is provided with a central aperture a, through which pass all the beams at the location of their Oberschneidung, so that the aperture a in the electrode 6 _'5 acts as a limiting diaphragm, so as to limit that the rays impinge with a sharply delimited spot on the screen S. In the tube according to Fig. 2, the three rays are therefore all shielded or diametrically limited by a common diaphragm which is formed by an electrode of the main focusing lens. as shown in Fig. 3, in a tube as described above in connection with Fig® X * the electron

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rays B _R , B _G and B "are limited or masked, for example in that the electrode G _{3 is provided} with limiting openings gop» g _3G and g _3B through which the respective rays enter the electrode G _{3 of} the main focusing lens.

Of course, according to the invention, the number of lens elements for the main focusing lens can be greater than two. So can,

2 As shown in FIG. H, the main focusing lens L m of a color picture tube is formed by successive, axially arranged electrodes G ₃ , G ₁ ,, Gr, Gg, G-, Gg and Gg, which are alternately connected to high and low potentials, to generate electron lens fields, which lens elements Lm ₁ and Lm ₂ around the axes of the electrodes G ₁ . and form Gg hrum and a third lens element Lm ₃ around the axis of the electrode Gg. The third lens element Lm ₃ is shown midway between the lens elements Lm ₁ and Lm ₂ and, when the latter are the same, the median plane of the lens element Lm contains the optical center 0

the main focusing lens Lm, at which the intersection of the rays B _R , B-, and B _ß is essentially. Therefore, as in the embodiment of Fig. 1, optical aberrations imparted to the rays B _{R and Bg passing through the lens element Lm 1} are fully corrected or compensated for by the opposite and equal aberrations generated _{by the lens element Lm 2.} Furthermore, since three lens elements in the main

2
focussing lens L m are present, the required focusing power can be achieved with lens elements which each have a further reduced refractive power, whereby the optical aberrations are greatly reduced, which are communicated to the beams and in particular to beams B_ and B "when they pass through the central lens element Lm ₃ pass along tracks at angles to the optical axis. Of course, the foregoing can be used in conjunction with

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Fig. 3 described arrangement in the color picture tube of Fig. H used to measure the diametrical size of the to limit beams focused on the screen.

Of course, the main focusing lens of a color picture tube according to the invention can comprise more than the three lens elements shown in FIG. For example, as shown schematically in FIG. 5, the main focusing lens L m can consist of four lens elements Lm ₁ , Lm ¹ ^, Lm ¹ ₂ and Lm ₂ , the lens elements Lm ₁ and Lm ^1. , In front of the optical center or the position of the beam intersection 0, while the lens elements Lm ' ₂ and Lm _{2 are arranged} following the center 0, seen in the direction of the rays from the cathodes K_, Κ «and Kg to the screen (not shown). As long as the rays B ₁₃ and B "through the lens elements Lm ₁ and

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If the optical aberrations communicated are counteracted or corrected by the same and opposite optical aberrations _{communicated by the lens elements Lm * 2 and Lm 2} , these rays are free from optical aberrations at their points of incidence on the screen.

In each of the embodiments of the invention described above, the main focusing lens was symmetrical, ie identical lens elements were arranged in front of and behind the optical center or the position of the intersection of the beams. As shown in FIG. 6, however, a color picture tube according to the invention can have an asymmetrical main focus lens L m which is formed by a lens element Lm _{1 in} front of the intersection O of the rays B ₀ , B _n and B _D and two lens elements Im ₂ and _{Im '2} , which are arranged following the upper intersection O and cooperate in such a way that the rays B, _R and B are communicated with optical aberrations which are opposite and equal to the aberrations which the rays are brought about by the lens element Lm ₁ .

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splits so that the rays are again free of aberrations at their points of impact on the screen (not shown) are,

Further, in the foregoing embodiments, the beams B _R , B _β and Bg have been converged to intersect at the optical center 0 of the main focusing lens by arranging the beam generating elements so that the beams B _R and B 'are mimicked along paths that are associated with converge with respect to the path of the central ray B. However, as shown in FIG. 7, the invention can also be applied to color picture tubes in which the beam generating surfaces of the cathodes K-, _KQ and K_ are arranged in a plane which is essentially perpendicular to the axis of the tube, so that the central beam Bg is mimicked coincident with the tube axis and the side beams B _R and Β »are mimicked parallel to the tube axis and on opposite sides of the latter · Furthermore, in this embodiment, the electrode G ' _{3 has} a portion of reduced diameter which extends in the cup-shaped grid G ₂ extends as shown so that when the voltage distribution described in connection with FIG. 1 exists, an electron lens field is created between the grid G ₂ and the electrode G ' ₃ to form an auxiliary lens L ₈ , such as with I indicated dashed lines by which the beams B _R and Bg are converged so that they are each other and the central beam Bg substantially at the optical Cross or intersect the center 0 of the main focusing lens L m, which is formed by the lens elements L m ^ and L m ₂ . In this case, the main focusing lens L m can be asymmetrical, that is, the lens element L m ₂ », which is arranged following the overlap 0, can be provided in such a way that optical aberrations are communicated to the side beams Bg and Bg which are equal to and opposite to the sum of the optical aberrations are "which the rays

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is communicated by the auxiliary _{lens L 8} and the lens element L m., which is arranged in front of the overlap O. Furthermore, in this embodiment, the focusing

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lens L m must be symmetrical, i.e. the lens elements L m.

and L m «can be the same, in which case the lens L m can be arranged with its optical center essentially at the point of intersection of the three beams, but at a small distance therefrom, whereby the aberrations of the beams B _R and B _ß which are brought in through the auxiliary or convergence lens Lg.

The invention is of course not restricted to the exemplary embodiments described, but can experience various changes within their framework.

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Claims (1)

Expectations II cathode ray tube, characterized by a beam generator for generating a plurality of electron beams, a receiving screen which is arranged so that it is acted upon by the rays mentioned, means, f by which the beams are brought to intersect at a point in the tube between the beam generator and the screen, a focusing lens arrangement which is provided so that the beams are focused on the screen, which focusing lens arrangement is formed by a plurality of lens elements which are arranged in axial succession are arranged and determine an optical center of the focusing lens assembly, which center is within the latter, and the focusing lens assembly is provided so that its optical cement is located substantially at the point at which the beams intersect, whereby g reduces the effects of certain optical aberrations' will. 2, cathode ray tube according to claim 1, characterized in that the focusing lens arrangement has a plurality of electrodes comprised of different electrical potentials to produce an electron lens field for each of the mentioned To generate LinFen elements. 3. Cathode ray tube according to claim 2, characterized in that 009846/1592 net that one of the electrodes mentioned on the optical Is arranged in the middle and has a limiting opening, through which all the rays mentioned pass to a diaphragm to limit the diametrical Form the size of the rays so that the rays cover the screen with sharply defined spots on the latter apply. Cathode ray tube according to Claim 1, characterized in that that the diaphragm to limit the diametrical size of the rays within the focusing lens assembly is arranged at the point where the rays intersect, so that the rays sharpen the screen impose limited spots on the latter. Cathode ray tube according to Claim 1, characterized in that that the focusing lens arrangement is a symmetrical arrangement of its lens elements. Cathode ray tube according to Claim 1, characterized in that each of the ones arranged in front of the optical center Lens elements and each of the lens elements arranged subsequent to the optical center, viewed in the direction beams determined from the beam generator to the screen, equal and opposite optical aberrations communicate so that these particular rays upon impingement on the screen are substantially free from the aforementioned optical aberrations. 7. cathode ray tube according to claim 6, characterized in 0 09846/1592 net that different numbers of lens elements are provided before and after the optical center. 8. Cathode ray tube according to claim 1, characterized in that the beam generator has separate beam sources, and the means by which the radiation fire are brought to overlap each other at the mentioned point, carry the separate beam sources so that the rays emerging from them at the mentioned point converge· 9. Cathode ray tube according to claim 1, characterized in that said rays from the beam generator emerge at a distance from one another, the means by which the rays to overlap at the point mentioned are brought, formed by an auxiliary lens arrangement which are arranged between the beam generator and the focusing lens arrangement and a convergence of the Bringing rays to the mentioned location, at least some of these rays passing through the auxiliary lens arrangement pass through areas of the latter which are at a distance from their aid, so that optical aberrations ■ ■ 's; » r / t '' tioneh * these particular rays are communicated through the auxiliary lens arrangement, and the focusing lens arrangement has lens elements which are before or after the mentioned place are arranged at which the Strah len intersect to the mentioned specific Rays communicate opposite optical aberrations, being the optical aberrations caused by the Lens elements and by the auxiliary lens arrangement 0-9 846/1592 be divided, cancel one another, so that the rays when they strike the screen are free of those mentioned are optical aberrations. The patent attorney 009846/1592 Blank page