FI63312C - AOTERGIVNINGSSYSTEM FOER FAERGTELEVISION - Google Patents

Description

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yggr · w ου utlaggningsskrift οόόΊΖ C (^ exam rayunnetty 10 05 1983

Patent tseddelat ^ ^ ^ (51) K * .ik? /Im.a.3 H 04 N 9/28 j FINLAND —FINLAND (21) Pttunttlhukemui —P »MiK» i »eiti * ij 1291/72 (22) Hekemlspllvl —Aw6lu * ig ^ «g 08.05-72 (23) Home - GlkJgk« ttdag 08-05-72 (41) Tullut IuIMmJuI - Latches offuntlig 15-07-73

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Patant- och ragittaratyralaan Anattku utiigd oeh utUkiUtaa puMeirad 31 - ui. 03 (32) (33) (31) Fjrrdsscy «cuolkwt-4« gM prtorttut 1 ^ · 01.72

England-England (GB) 01779/72 (71) RCA Corporation, 30 Rockefeller Plaza, New York, N.Y. 10020, USA (72) Robert Lloyd Barbin, Lancaster, Pennsylvania, USA (7 * 0 Oy Kolster Ab (5I +) Color Television Display System - Atergivningssystem för färg-telev The present invention relates to a color television display system and a method for utilizing it, and in particular a display system including a cathode ray tube including a vacuum jacket including an image surface having a repetitive pattern of three differently colored strips of color phosphorus, a multi-hole perforated plate inside the jacket and a plurality of vertically extending apertures aligned with phosphor strips a cannon structure disposed within the sheath at one end of the neck opposite the image surface and including electrodes forming a main focusing lens near the electron beam output end of the electron gun, a static convergence structure disposed in the vicinity of the electron cannon structure to generate a magnetic field within said neck portion so as to converge said three rays in the center of the image surface, and a deflection coil unit comprising a hollow ferrite magnetic core having an inner circumferential dimension larger than the outer circumference of the sheath or its attachment is disposed around the neck of the sheath; that the deflection coil unit can be moved in the transverse direction with respect to the sheath axis and the horizontal deflection coil forming a magnetic field to deflect the radii in the horizontal axis and having a negative astigmatism, and the vertical deflection coil forming a magnetic field deflecting the windings deflect the rays to sweep three overlapping rasters onto the image surface.

The most common color television receiver currently in use uses a delta cannon-perforated plate picture tube in which three electron beams emanating from the vertices of a triangle formed by the cannons are deflected to scan a raster on a phosphor picture surface. It is essential that the electron beams remain converged at all points on the image surface so that the three different color rasters become superimposed. For this purpose, an electromagnetic, dynamic convergence correction device is usually used, located around the neck of the color picture tube in the area where the rays leave the cannon. This convergence correction device usually includes three electromagnets located around the three inner pole pieces of the picture tube and magnetized at horizontal and vertical scanning frequencies to dynamically adjust the correction for different radii so as to ensure satisfactory convergence at all points on the image surface. The waveforms applied to the electromagnets can be adjusted appropriately to provide the desired correction. Although this dynamic correction device works satisfactorily, it is relatively complex and therefore relatively expensive, thus increasing the cost of a color television receiver. In addition, due to the complexity of the device, considerable time is required for proper adjustment.

In some cases, color television picture tubes with three horizontal in-line electron beams have been used instead of delta cannon picture tubes to simplify the equipment needed to maintain beam convergence. For example, in a color television picture tube using three horizontal, inline beams and a phosphor element image surface using a structure of vertical phosphor strips of different colors, the device for achieving dynamic convergence can be simplified, although dynamic convergence is still required. It is obviously desirable to develop a color television receiver that does not require dynamic convergence correction at all.

It is therefore an object of the present invention to provide a system for parallelizing an electron beam and a deflection coil unit to achieve convergence of a plurality of in-line beams.

According to the invention, a color television display system has been developed, characterized in that the lens electrodes include a common electrode with three apertures defining passage areas of the respective three beams, where the beams are precisely positioned relative to each other as they leave the main focusing lens. the astigmatism characteristics of the fields formed by the vertical windings are proportionally proportional to the convergence of the three radii at the corners of the grids as well as at other raster points;

The method for utilizing the display system described above is characterized in that the deflection coil unit is mounted relative to a color image tube comprising a sheath containing a color phosphor image surface, an electron gun structure for transmitting multiple electron beams to the image surface and deflection region adjacent to the deflection area, the tube and deflection coil unit are used to direct the beams toward the image surface and deflect the beams into separate rasters on the image surface and simultaneously adjust the transverse position of the deflection coil unit fixed to the picture tube in the adjusted position.

The invention is described in more detail in the following description of its preferred embodiment and the accompanying drawings, in which Figure 1 shows a system according to the invention for converging several in-line beams, Figure 2 shows a characteristic curve of the magnetic deflection field produced by the deflection coil unit of Figure 1; The effects of the magnetic deflection field shown in Fig. 2 on the two outer electron beams shown in Fig. 1, and Fig. 5 shows a partial cross-section of the deflection coil unit and the picture tube shown in Fig. 1.

Figure 1 shows a system according to the invention which provides hardening of several in-line electron beams. Figure 1 shows the main parts of a color television receiver. The color television picture tube includes a glass shell 11. At one end of the shell 11 there is a transparent front plate 12, inside which are repeatedly formed groups of blue, red and green phosphor elements 13a, 13b and 13c. A short distance from the phosphor elements is a perforated plate 14 with a plurality of openings 15. Inside the neck portion of the shell 11 is an electron gun structure 16 at one end of the image tube, which provides three horizontal, in-line beams 17a, 17b and 17c. The beams are modulated according to the video signals so that they represent the blue, red, and green colors of the television image, respectively. A deflection coil unit 18 is placed around the neck portion of the image tube and adjacent the applied portion of the shell 11, which, when connected to vertical and horizontal frequency scanning currents, causes the electron beams 17a, 17b and 17c to scan the respective screens over the phosphor elements. The deflection coil unit 18 is held in place by its mounting means 18a, which will be described in more detail later.

Around the neck area of the picture tube in the area where the electron beams emanate from the electron gun structure 16 are a static beam converging device 19 and a beam cleaning device 20. The static beam converging device 19 may include a plurality of permanent magnets 5,63312 that statically converge beams in the center of the phosphor image surface. The beam cleaning device 20 comprises two annular, magnetized rings which are adjusted simultaneously to achieve purity, i. to ensure that the rays corresponding to the corresponding colors coincide with the corresponding color phosphor elements.

In the preferred embodiment, the phosphorus elements 11a, 13b and 13c are vertical phosphor strips and the openings 15 are elongate slits which also extend vertically. Such a vertical structure of the phosphor elements eliminates the vertical alignment problems, because if the rays are slightly misaligned in the vertical direction, however, a certain radius hits its corresponding color phosphor, because the phosphor strips extend over the entire vertical dimension of the screen. However, the vertical error direction of the rays causes a convergence problem and this and its solution are described below. The arrangement described heretofore in connection with Figure 1 is described in detail in U.S. Patent Application No. 217,780, filed January 14, 1972, filed in A.M. Morrell et al. entitled "Safe-converging color television display system".

Fig. 2 shows a characteristic curve of the magnetic deflection field produced by the deflection coil unit shown in Fig. 1. As described in the above application, a certain selection of the electron gun structure 16 and the deflection coil unit 18 provides substantial convergence of the beams at all points of the scanned raster without the need to use a dynamic convergence correction device. The deflection coil unit used for this purpose is characterized by a negative horizontal isotropic astigmatism and a positive vertical isotropic astigmatism. Figure 2 shows a dominant magnetic field provided by a deflection coil unit having these astigmatic properties. In Figure 2, the force lines show 25 horizontal magnetic fields. The pad shape of the field is due to negative horizontal isotropic astigmatism. The strength of this pad-shaped deflection field increases as the distance to the center increases along an axis parallel to the horizontal deflection direction. At the same time, the strength of this cushion-shaped field decreases along an axis perpendicular to the horizontal deflection direction.

In Fig. 2, the force lines 26 show a vertical magnetic deflection field provided by a deflection coil unit having a positive vertical isotropic astigratability. This vertical field is barrel-shaped and this barrel-shaped vertical deflection field intensifies along the horizontal axis and weakens along the vertical axis. The preferred embodiment of an exception coil unit with this type of field is disclosed in Patent Application No. 217,768 filed in the United States on January 14, 1972 by V.H. Barkov et al. titled "Deflection joke for use with in-line Electron Guns".

The magnetic flux distribution of the deflection coil unit, illustrated in connection with Figure 2, is designed to converge completely parallel beams. If the beams are not properly aligned with the center of the magnetic field of the deflection coil unit, the beams will not converge on the image surface. The beams may be misaligned with respect to the magnetic field of the deflection coil unit if the electron gun is misaligned within the picture tube, if the deflection coil unit is misaligned with respect to the radii or the neck of the tube, or if the coils of the deflection coil unit are asymmetrical. In general, if there are variations in the placement of the electron gun inside the picture tube or in the winding of the deflection coil unit, this will result in a bias error trend relative to the magnetic field of the deflection coil unit. In the system of Figure 1, in which no dynamic convergence correction device is used, the rays do not converge unless steps are taken to align the rays with the magnetic field according to the invention.

Figures 3 and 4 show the effects of the magnetic deflection field of Figure 2 on two outer beams of the three in-line electron beams when the beams are misaligned with respect to the magnetic field of the deflection coil unit. Fig. 3a e-shows a state in which the blue and green rays 17a and 17c are misaligned vertically with respect to the center of the horizontal deflection field represented by the force lines 25. The dashed lines indicate magnetic flux and the intact arrows pointing away from the 7 63312 rays indicate the general direction and amount of beam displacement caused by the misaligned position of the rays. To simplify Figures 3 and 4, the middle of the three rays, namely the red beam 17b, has been omitted because it can be generally said that the effect on the central beam is that it is sandwiched between the u-notches, the blue and the green beam.

In Fig. 3a, the blue beam and the green beam are equally strong in the magnetic field because they are equidistant in the horizontal direction from the center of the field, but the directions are different so that when the rays bend to the right, the blue beam also bends up and the green beam down. When bending to the left (when changing the indicated polarity of the magnetic field), the blue beam would be undesirably folded down and the green beam up. The consequence is that along the horizontal or X-axis there is a blue radius at the bottom left of the raster and at the high right in relation to the green radius. If the rays had been misaligned downward from the central axis and not upward, the blue radius would be on the high left and bottom right relative to the green beam.

In Fig. 3b, the blue and green beams are misaligned horizontally to the right in the horizontal deflection field 25. As described by e, the strength of the pad-shaped horizontal deflection field increases as its distance from the center increases along the horizontal axis. A misaligned green beam that is farther from the center than a blue beam is therefore in a stronger magnetic field and bends more. The result is that the green raster is wider than the blue raster. It is obvious that if the polarity of the deflection field were changed, as when the rays have to be folded to the right of the raster, the green beam would bend similarly farther than the blue. If the rays had been misaligned to the left of the center and not to the right as shown, the green raster would be smaller than the blue raster.

Fig. 4a shows the effect on the rays when they are misaligned vertically, in the upward direction, under the influence of the vertical magnetic deflection field shown by the force lines 26. The blue beam moves to the left at the top of the raster and to the right at the bottom of the raster relative to the green beam due to the direction of the magnetic lines 8 63312.

Figure 4b shows the effect of the horizontal error direction of the rays in the vertical deflection field. Because the green ray is farther from the central axis than the blue, it is in the stronger part of the field and therefore bends a greater distance vertically-straight than the blue ray. As a result, the green raster is larger in the vertical direction both at the top and bottom than the blue raster.

It is shown how the error direction of the electron beams with respect to the vertical and horizontal magnetic field causes error convergence. The horizontal error direction of the rays causes variations in the size of the rasters in both the vertical and horizontal directions. The vertical error direction of the rays causes the rasters formed by the two outer rays to rotate in opposite directions from each other.

Figure 5 shows a partial cross-section of the deflection and image tube of Figure 1. According to the invention, it has been found that the error convergence of the beams caused by the error direction of the beams with respect to the magnetic field of the deflection coil unit can be greatly reduced by positioning the deflection coil unit with respect to the radii so that its magnetic deflection center is aligned with the two outermost radii. Fig. 5 shows a deflection coil unit 18, in this case conductors 21, only a part of which is shown, which is toroidally wound around the core, designed so that the smallest inner diameter of the deflection coil unit is larger than the outer diameter of the neck of the picture tube 11. In such an arrangement, the deflection coil unit can be moved laterally in the X and Y directions or in any direction in the X-Y plane so that its magnetic field is aligned with the electron beams to achieve substantial convergence of the rays on the phosphor image surface. It is important to note that according to one aspect of the present invention, the deflection coil unit positioned in the X-Y plane around the picture tube housing 11 is moved transversely so that the center longitudinal axis of the deflection coil unit or its center deflection field is aligned with or parallel to the center radius axis. Previously, mounting means for a deflection coil unit have been developed which allow the deflection coil unit to be tilted relative to the neck of the picture tube so that the deflection coil unit is no longer in the X-Y plane. This tilt corrects a coma in the color television delta artillery tubes, with the result that the blue raster had a different width than the red or green raster. Such an arrangement required dynamic convergence correction of all rays to properly converge the rays on the phosphor image surface. It has been found that in the arrangement described in connection with Figure 1, the mere tilting of the deflection coil unit could result in a beam misalignment on the phosphor image surface. However, by using the described transverse motion of the entire deflection coil unit, the beam orientation with the color phosphor elements is not disturbed and convergence is achieved without the need for a dynamic convergence correction device.

It has been found that, for example, in a color television picture tube described in connection with Figure 1 with a screen diagonal of 38.1 cm (15n), a radial clearance of about 1.27 mm (50 mils) is provided between the outer diameter of the tube neck and the smallest inner diameter of the deflection coil unit. so as to achieve o-alkaline convergence of the rays. It has been found that a displacement of about 1.27 mm (50 mils) in the horizontal direction of the deflection coil unit resulted in a 1.27 mm (50 mils) change in convergence at the horizontal sides of the rasters. According to the examples of Figures 3 and 4, the horizontal displacement of the deflection coil unit by about 1.27 mm (50 mils) to the right causes the blue grid to increase by about 1.27 mm (50 mils) on each side relative to the green as the blue grid size increases and the green grid size decreases. . With this same horizontal displacement, the blue raster becomes about 0.63 mm (25 mils) larger than the green raster at the top and bottom of the raster. The sensitivity for the vertical displacement of the deflection coil unit is approximately the same as for the described horizontal displacement. The changes are such that the blue and green raster move in opposite directions to the red one, which is located between the blue and green itself. The change in convergence at angles as the deflection coil unit moves is a combination of changes in convergence on adjacent vertical and horizontal axes.

10 6331 2

It is obvious that the relatively small displacement of the deflection coil unit can provide a substantial convergence correction. Therefore, it is highly desirable that the deflection coil unit be firmly attached to the desired operating position relative to the picture tube. For this purpose, suitable means for mounting the deflection coil unit are used, by means of which it can be positioned correctly in order to achieve the best overall convergence and then fixed in place. Several easy ways to install the deflection coil unit as described are described in Patent Application No. 217,756, filed in the United States on January 14, 1972 by T.M. Shrader titled "Cathode ray tube-yoke platform-yoke combination and method of assembling.the combination".

In this application, one method of mounting the deflection coil unit is such that the mounting bridge is permanently tied to the picture tube, the mounting portion is permanently attached to the deflection coil unit, and its mounting portion is loosely attached to the bridge while the deflection coil unit and tube are used to determine the best position on the deflection coil. When this position is ensured, such as by observing the convergence of the lines in the grid caused by the picture tube by connecting a suitable test signal to the television set, the deflection coil mounting part and the bridge are firmly attached to each other by a binder or mechanical means such as nuts and bolts.

The described means for mounting the deflection unit do not limit the invention. It should be noted that any mounting means can be used with the present invention which allows the transverse movement of the entire deflection coil unit and not only the tilting movement and which allows the deflection coil unit to be permanently fixed in the desired position.

A method of aligning the magnetic field of the deflection coil unit with the beams to achieve convergence and a device of holding the deflection coil unit permanently in the desired operating position would be utilized during manufacture of the television receiver when the deflection coil unit and tube are used during a suitable pattern such as a lattice pattern? on the phosphor image surface so that the installer can observe this and find out the best position of the deflection coil unit to achieve convergence.

The invention has been described in connection with a color television detection system in which the features of the invention eliminate the need for dynamic convergence correction waveforms and apparatus. However, the invention can also be utilized with a dynamic convergence correction device to supplement the system convergence correction rate or to simplify and reduce the cost of an existing convergence correction system, e.g., by eliminating some or all of the controllable control elements or reducing the number of convergence correction waveform circuits.

Claims (5)

12 6331 2 A color television display system including a cathode ray tube including a vacuum jacket (11) including an image surface (12) having a repeating pattern of three different vertically arranged color phosphor strips (13a, 13b, 13c), a multi-hole perforated plate (14), inside the sheath and including a plurality of vertically extending apertures (15) aligned with the phosphor stripes, an electron gun structure (16) for generating three in-line electron beams disposed inside the sheath at one end of the neck opposite the image surface and including electrodes forming a main focusing lens an electron gun output beam, a static convergence structure (19) disposed in the vicinity of the electron gun structure to generate a magnetic field within said neck portion to converge said three beams in the center of the image surface, and a deflection coil unit (18) disposed around the neck of the sheath (11); a magnetic core having an inner circumferential dimension larger than the outer circumferential dimensions of the sheath (11) in its mounting position with respect to the sheath so that the deflection coil unit can be moved transversely to the sheath axis and a horizontal deflection winding forming a magnetic field a vertical deflection winding which generates a magnetic field for deflection of rays in the vertical axis and has a positive astigmatism, which windings deflect the rays to sweep three overlapping rasters on the image surface, characterized in that the lens electrodes include a common electrode with three apertures defining three apertures positioning the rays precisely with respect to each other as they leave the main focusing lens, the astigmatism characteristics of the fields formed by the horizontal and vertical windings being proportional to the substantial i converge three beams at the corners of the grids as well as at other points of the grids and the deflection coil unit mounting device (18a), 6331 2 13 located outside the sheath to support the deflection coil unit, allows the deflection coil position to be adjusted to accurately align the deflection coil field. A color television display system according to claim 1, characterized in that the deflection coil unit (18) comprises a pair of vertical and a pair of horizontal deflection coils toroidally wound around the core, the coil conductor distribution being selected to produce positive vertical isotropic astigmatism and negative horizontal astigmatism. A method of utilizing a color television display system according to claim 1, characterized by mounting a deflection coil unit relative to a color image tube comprising a sheath (11) including a color phosphor image surface (12), an electron gun structure (16) for transmitting a plurality of electron beams to the image surface and deflection area radii. position, the deflection coil unit is temporarily supported loosely mounted around the picture tube adjacent to the deflection area, the tube and deflection coil unit are used to direct the beams toward the image surface and deflect the beams and finally the son the cooking coil unit is fixedly attached to the picture tube in the adjusted position. 14 6331 2 A transmission system for a television television, including a cathode ray tube, a vacuum and a vacuum oil (11), a monitor and a picture belt (12) having a vertical light source (13a, 13b, 13c), and a mask (14) , the light is isolated on the other side and on the other side of the vertical wire (15) is not in the phosphor structure, in the electron channel structure (16) on the other side of the in-line electronic gear, the light structure is in the light and in the light of the light is not bildskärmen och innehäller elektroder, vilka bildar en huvudfokuseringslins närä elektronsträlarnas agängs-ände ur elektronkanonen, en statisk kongeringsstruktur (19), somä belägen i närheten av electronkanstrucstructen fört alst a bät astär et magnetfält inne i nämnda h , och kring höljets Hals är belägen en avlänkningsspolenhet (18), som innehäller en ihälig, ferritisk magnetkärna, arm dimensioner main inre omkret - its structure is dimensionally fixed (11) and the dimensions of the measuring instruments in the field are fixed to the field in which the magnetic field is fixed, the axis of the magnetic field is fixed, axial displacement and somewhat negative astigmatism and vertical vertical displacement, with alphanumeric magnetic displacement on the ground and vertical displacement of the vertical axis, and positive displacement of the axle, positive axis of rotation Whereas, in the case of a lens electrode, the electrodes of the electrodes are of the same type as those of the field of interest, horizontal and vertical ground the result is proportional to the value of the convergence of the three lines and the value of the number of lines and the number of lines (18a) of the number of spheres and the number of spheres