KR840001000B1 - Self conversing color image display system - Google Patents

Abstract

This invention concentrates multiplex electron-beams at all the points of a scanning raster without using a dyanmic convergence apparatus. The TV set(10) includes a glass-tube(11) whose front side has a surface panel (12). The inside of the surface panel is coated with red, green, and blue fluorescent elements (13) (13a) (13b).

Description

Self Converging Color Image Display System

1 is a plan view of a cross section of a color television display system according to the invention;

2 is an explanatory diagram of a deflection magnetic field generated by the deflection yoke described in FIG.

3 illustrates the convergence of the electron beam of the FIG. 1 system under the influence of the deflection magnetic field of FIG.

4 is a winding distribution diagram of a toroidal deflection yoke suitable for use in the system of FIG.

FIG. 5 (a) is a view showing an electron gun that can be suitably used in the system of FIG.

Fig. 5 (b) (c) is a diagram for explaining the present invention, and Fig. 5 (c) is a diagram corresponding to the configuration of Fig. 5 (a).

6 is a screen structure in which an aperture mask and a phosphor element are coated for use in the FIG.

The present invention is directed to a color television display system that allows virtually all points of a multi-beam scanning raster to be used without the use of a dynamic convergence device.

All color television receivers used today use cathode ray tubes in which a plurality of electron beams are generated by an electron gun disposed on one inner side thereof and scanned onto a screen containing a plurality of different color phosphors disposed on the other side thereof. An aperture mask or other color selector, such as an aperture grill or focusing grill, is placed between the screen and the electron gun to screen the electron beam so that each electron beam is scanned only on their corresponding color phosphor. The deflection yoke disposed around the outside of the cathode ray tube is driven to generate a magnetic field that deflects the beams horizontally and vertically to form a raster scanned on the screen. Such display systems may additionally have other devices capable of performing dynamic convergence correction. One requirement in this display system is that the beams should be concentrated on every point on the scanned raster.

Misconvergence causes unwanted fringes of colors that appear on the edges of the picture. Misconvergence can be measured as the ideally overlapping red, green and blue lines of the crosshatch pattern appearing on the raster when the appropriate test signal is applied to the receiver.

It has been common practice to focus the beam at the center of the raster using a device, such as a permanently placed permanent magnet for the beam, around the abdomen's abdomen. Since the screen is relatively flat and the distance between the center of deflection of the yoke and the screen increases as these beams are deflected from the center of the screen, the beam is not concentrated as it is deflected from the center of the raster to the edge. In addition, deflection yoke errors such as image field curvature, astigmatism or coma cause additional convergence errors.

Conventionally, these beams usually have a device for dynamically concentrating them as they are injected onto the raster. The water tube using a delta-type gun with three electron guns placed at the vertex of an equilateral triangle uses an electron-convergence part, which is located outside the tubule and moves the beams in the radial direction as the magnetic poles are excited. Move to. These electromagnets are excited by waveforms at horizontal and vertical refresh rates to provide a convergence field that changes over time as the beam is scanned. Sometimes the horizontal refresh rate waveform is modulated from the vertical refresh rate waveform and combines the waveforms at the horizontal and vertical refresh rates and applies this combined waveform to the convergence electromagnet or deflection yoke winding to converge the beam at the corners of the raster. Needs to be improved.

Conventionally, color television receivers, which have a color receiver which is equipped with an electron gun which generates three types of coplanar or in-line beams, are usually located in a horizontal line. By applying suitable horizontal and vertical scanning waveforms to the electromagnet or electrostatic convergence device, the beam can be dynamically concentrated in the horizontal direction. These beams may be concentrated by deflected yokes, but other yoke errors, such as commas, must be corrected for the yoke to accomplish this purpose. The device used for dynamic coma correction negates the cost savings obtained by eliminating the horizontal dynamic convergence device.

Unnecessary effects of coma and misconvergence can be reduced by reducing the spacing between in-line beams in the yoke deflection plane. This can be accomplished by reducing the spacing between adjacent beam forming elements of the electron gun. The closer the in-line beams are in the deflection plane, the smaller the passage of the beam in the aperture mask is to maintain the screen tolerance between the fluorescent element and the fluorescent spot printed on the screen.

Although a reasonable and acceptable amount of coma can be produced by a system using in-line electron beams with relatively low separation, if the screen is not clear enough to view comfortably under normal viewing conditions, The result is unacceptable.

It is an object of the present invention to provide a color television display system which does not require dynamic convergence and coma correction devices and whose screen brightness is commercially acceptable.

The color image display system according to the present invention comprises a color television receiver having an electron gun generating three horizontal in-line beams, a color selection electrode having a plurality of openings for screening the beam, and a plurality of applied to the screen. Of different color phosphor elements.

The electron gun includes at least one common beam forming electrode with three openings. Because the deflection yoke was installed around the outside of the water pipe, the beam scans the raster on the screen. The yoke's deflection winding is chosen to establish a negative horizontal isotropic astigmatism and a positive vertical isotropic astigmatism shape. This causes the beam to be underconverged along the horizontal axis and overconverber the beam along its vertical axis, thereby substantially concentrating on all points of the raster.

According to one embodiment of the present invention, the screen of the receiving tube is composed of phosphor strips formed by adjacent three different phosphors. The color selection electrode used for this screen contains a number of slit apertures that extend in line with the phosphor strips, allowing more electrons to excite the phosphor strip to generate more light output.

According to another embodiment of the present invention, the electron gun includes magnetic shielding means installed around a passage of two outer beams of the three electron beams.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1 the color television receiver 10 according to the invention comprises an evacuated glass tube 11, the front side of which has a surface plate 12 and the inner surface of the surface plate having a number of red, green and blue colors. The phosphor elements 13, 13a and 13b are coated. In the tubing is located an aperture mask 14 comprising a plurality of openings 15 adjacent the phosphor elements.

The openings 15 are arranged such that the electron beams through these openings impinge only on their corresponding color phosphor elements.

The outer trumpet-shaped portion of the glass tube 11 has a deflection yoke 17, which is operated by a suitable power source, not shown, to generate a magnetic field which is deflected to the electron beams and scanned onto the screen. Form the studs. The deflection plane C, where the beam which deflects and reaches the screen, begins to spread, is located perpendicular to this side in the middle of the yoke axis.

A more detailed description of the deflection yoke 17 is described above with reference to FIGS. 3 or 4.

At the neck of the glass tube 11 is located a static convergence assembly 18 behind the deflection yoke 17. The static convergence assembly 18 has a magnet that can move its position to compensate for errors in the alignment of the electron beam and to focus the beam at the center of the screen when the electron beams are not biased. To be.

Suitable static convergence parts that can be used with in-line guns are Robert L. It is described in Baibin's US patent application (RCA 65707) “Self-adjustment Structure”. Behind the beam convergence assembly 18 is a beam purifier 19 having a conventional structure, which serves to allow the beams to land on their corresponding collar narrower elements.

The electron gun 16 of the knitted yoke 17 will be described later in this description of the components of the device shown in FIG. 1, but using a supplementary device for dynamically concentrating the beam or correcting coma effects. There is no work, and the electron beams cooperate to focus on satisfactory opponents at all points on the scanning raster.

FIG. 2 shows the polarization field generated by the yoke of FIG. 1 where the non-uniformity of the horizontal and vertical magnetic fields can vary at various points along the axis of this tube, but the overall effect of this magnetic field is As shown in the figure. The horizontal polarization magnetic field generated by the pair of horizontal polarization coils is indicated as a solid magnetic flux line 21 extending vertically. This magnetic field has a pincushion shape, and this magnetic flux line is convex on the convex surface when viewed from the center of the drawing. This horizontally polarized magnetic field produces a negative horizontal isotropicastigmatism of the entire beam.

The vertically polarized magnetic field generated by the pair of vertically polarized coils of the knitted yoke 17 is represented as a magnetic flux line 22. This vertically polarized field has a barrel shape and has two concave surfaces when viewed from the center of the drawing. This vertically polarized magnetic field produces a positive perpendicular orthotropic astigmatism of the beam. The purpose of generating the deflection field described above is explained with reference to FIG.

FIG. 3 illustrates a large version of the electron beam of the system shown in FIG. 1 at the nutritional value of the magnetic field of FIG. FIG. 3 (a) shows the relative positions of the green, chuck, and blue beams 20a, 20b and 20c, respectively, as they appear in the yoke's plane of plane (plane C in FIG. 1). FIG. 3 (b) shows, in magnification, the large version of the beam at the corners of the scanning master and also at the vertical and horizontal deflection axes 25 and 26. Each electron beam simultaneously illuminates several phosphor elements of a particular color. These narrower elements are of course separated from each other, which is not shown in Figure 3 (b), which illustrates the large version of the total beam in the various areas of the surface plate.

At the center of this raster are concentrated green, red and blue beams.

This central large shift is achieved by the alignment of the electron beams established by the structure of the electron layer and the action of the static convergence assembly 18. On the horizontal deflection axis 16, the green, red and blue beams are undevolved, i.e. the beams are separated along the horizontal axis, the order of separation being the order of the beams in the plane of deflection in Figure 3 (a). Is the same as

This state exists at both ends of the raster along its horizontal axis. Underbeam of the beam at both ends of this level is reduced as a function of distance from the center of the raster. Underversion of this horizontal beam is generated by the horizontal polarization magnetic field shown in FIG.

On both sides of the vertical axis 25 of FIG. 3 (b), the red, green, and blue beams are marked as over-verified, i.e., in the surface plate where the fluorescent and blue beams intersect at some point, These blue and green beams are located on opposite sides of the yoke in comparison to their positions in the planar plane.

Overconvergence of these beams along the vertical axis is reduced as a function of distance from the center of the raster, which is also caused by the vertically polarized magnetic field shown in FIG.

This convergence state of the beams is the result of designing the biasing yoke to exhibit some negative horizontal homogeneous astigmatism and some positive vertical isotropic astigmatism. Although the beam has been described for overconverging along the vertical axis and undeconverging along the horizontal axis, other states of misconvergence connected to these axes can be used to make an acceptable concentration throughout the raster. Be aware that it can be.

By proportionally balancing the astigmatism in the deflection coils, it has been described above that the electron beams can be practically concentrated at the corners as well as at all other points of the raster, as shown in Figure 3 (b). Next, the Coney convergence shown in the raster's upper and lower constitutions of FIG. 3 (b) shows that the blue and green beams have a slight offset in the vertical direction compared to the red beams. In the upper left corner, the blue and green beams have different positions for the red beams as opposed to the ones in the right corner. This effect on rasters is known as a "tram" and under these conditions, these rasters form a floating-side rectangular shape whose overall shape is slightly shaped from a rectangular shape. Conventionally, line-focus yokes are used to produce a large traverse of the beam ideally depending on the lateral side, but to generate a large tram that is unacceptable only in the corners. The switch state is characterized by the horizontal side as well as the large vertical difference between the beams.

The ideal line focus yoke has negative horizontal isotropic aberration and positive vertical isotropic astigmatism. This type of astigmatism is necessary to maintain the convergence of three horizontal in-line beams along the horizontal and vertical deflection axes. Biaxial convergence conditions can lead to prolonged cornering of the raster and thus ideally achieve beam convergence at all points of the raster. In practice, it has been demonstrated that this ideal line focus condition may only be possible in a water tube with a screen diagonal length of 14 inches (about 35.56 cm) or less. The line focus condition is not realized in the picture tube having a larger screen diagonal length, and the trap condition of FIG. 3 (b) is generated. In the presence of this trap as a feature of the present invention, the positive and negative astigmatism must be proportionally balanced between the vertical and horizontal deflection coils, so that the conductors are established so that practical convergence conditions are established at all points of the raster. This can be done by appropriately selecting the winding division.

The actual convergence described herein indicates a convergence condition that can be tolerated commercially. It is common to set a misconvergence limit in the design specification of this receiver in the production of a given television receiver. It is necessary to keep this misconvergence as close to zero as possible. In practice, zero misconvergence is impossible due to manufacturing error. For example, according to the manufacturer's design limitations, the beam's misconvergence measured at a half inch distance from the edge of the scanned raster has a screen diagonal length of 15 inches (about 38 cm). It should be less than 50 mils (approximately 1.6 mm) from the water. This design limit can be increased for large screens and can be about 62 mils (about 1.6 mm) in a water tube with a 25 inch (63.5 cm) diagonal screen. In real history, the manufacturing errors described above, in particular the color receiver and yoke errors, establish the distribution of convergence errors for each receiver. Some receivers may have much less error than the 50-mil (about 1.6) design limit, while other receivers manufactured through the same parts and the same manufacturing process may have larger misconvergence. It was found that the actual commercially available water receiver had a misconvergence error of more than 125 mils (about 3.18 mm). The actual convergence used here means a miss convergence of less than 125 mils (about 3.18 mm). The misconvergence of the beams can be observed by the separation of the ideally overlapping red, blue and green scan lines of the crosshatch pattern appearing on the screen when a suitable test signal is applied to the television receiver. Fabrication errors in yokes and water pipes can cause convergence errors of more than 0.125 inches (about 3.18 mm), especially if they are assembled properly, but this condition is not common, which is why the present invention can be used appropriately. The result is not generated.

The deflection yoke described here and described in William Ech Barkow's U.S. Patent Application (RCA 60857) "Bias Yokes Used in In-Line Electron Guns" provides a raster by distributing astigmatism between the horizontal and vertical deflection windings. At all points in the beam, the true convolution of the beam is established.

The winding distribution of the toroidal deflection yoke shown in FIG. 4 is suitable for generating the convergence characteristics shown in FIG. 3 (c), and the yoke is connected to the conductors forming a pair of vertical deflection coils. 31) and a pair of horizontal deflection coils are formed as conductors 32, which are wound around a ferrite core 30 in the form of a toroid (conical curved surface). Its return conductors are located outside of the ferrite core 30.

In FIG. 5 (a), the electron gun 16 has three cathodes 35a, 35b and 35c, which generate three electron beams. Electrons emitted by these cathodes are sequentially accelerated by the G ₁ ′ electrode 36, the G ₂ electrode 37, the G ₃ electrode 38, and the G ₄ electrode 39, formed into a beam, and connected. Although not shown, these cathodes and other electrodes are held in relative positions, respectively, by suitable beading strips attached to them.

This electron gun 16 provides three electron beams concentrated at the center of the screen of FIG. 1 when there is no deflection magnetic field formed by the deflection yoke. In order to establish this concentrated condition, the straight alignment and spacing of the relative positions with respect to each of the electrodes, in particular, the other electrodes of G3 38 and G4 39, becomes an important factor. In addition, the difference between the curvature of G4 and the aperture with respect to the G3 electrode 38 leads to two beams along the convergence path to the center beam. All of these electrodes have three openings through which the beam passes. This facilitates the construction of the correct citron gun to achieve the required alignment in the unique vertical direction. Minor errors in the beam alignment (convergence at the center of the screen) are corrected by appropriate measures of the static convergence portion described above. The electron gun should be selected to establish spacing of less than 250 mils (about 6.36 mm) between the beams in its deflection plane.

In order to achieve the concentrated state, alignment in the spacing between the various electrodes, in particular the G3 electrode 38 and the G4 electrode 39, is critical.

Looking at the fifth (a) (b) (c), it can be seen that the apertures of the G4 electrode 39 are offset outward from the apertures of the G3 electrode 38. To account for this offset effect on the electron beam, basic electro-optical theory can be employed. In this regard, to make the construction of FIG. 5 (a) easier to understand, the diagram of FIG. 5 (b) (c) is shown as “pictorial”. 5 (b) (c) is G3 (38). The effect on the electric field and the beam associated with the G4 electrode 39 is illustrated. These beams are not deflected from the straight path as they are accelerated through the center of the G3 electrode 38 and the center rode of its equipotential line. In FIG. 5 (b) these beams are also accelerated through the offset outer apertures of the G4 electrode 39 so that they do not pass through the center of the equipotential line of the G4 electrode 39. Since the beams tend to escape in a direction perpendicular to the tangent of the equipotential line, the outer beams are bent inward. (Focused). As shown in FIG. 5 (c), the curved G4 electrode 39 may have a larger offset of the equipotential line from the non-passage path than the offset of the unbent wire, thereby causing the beam to be bent in the concentrated direction to increase. .

In large color water tubes with screen lengths greater than 15 inches (about 38 cm), the raster injected by the two beams may need to be coma corrected to be the same size as the one scanned by the center beam on the screen. have. Coma is generated by the deflection yoke, and if present, tends to be more disturbing to viewers as the screen size increases. To fix this coma effect, annular shields 40 and 41 made of permeable material such as Nickel-Iron can be placed around the exit hole of the G4 electrode 39. The shield protects both beams from a portion of the deflection field so that the effects of the deflection field are given equally to the beam, resulting in three equally sized rasters. An electron gun of the type described above is described in detail in US application 217,758, "In-line electron gun for color receivers" of Richard Henry Hughes, filed January 19, 1972.

Deflection yokes have a relatively small gap between the inner surface of the yoke and the glass surface and are installed around the outside of the surface of the water pipe, which is about 1/4 inch (6.35 mm) or less. The deflection yoke of the described type can be moved vertically to the side of the water pipe to generate the optimum convergence of the beam. The static convergence portion is first adjusted to establish the beam's convergence at the center of the raster, and then the yoke is moved perpendicular to the water column axis until the optimal total convergence is achieved at the raster. The yoke is then fixed.

The satisfactory convergence of the beam in all parts of the raster is achieved with the present invention by the use of a yoke of the type described above, the yoke being properly positioned and the exact in-line described in conjunction with the fifth (a) diagram. Combined with an electron gun. The use of porous common electrodes in the electron gun combination allows the electron gun to provide a determined straight array of beams so that they are actually concentrated in the center of the screen. The yoke's coil windings are beams without unevenness in the net deflection field, i.e., negative horizontal isotropic aberration and positive vertical isotropic aberration, without causing the beam to fall from the experimental convergence at all points of the stripes. It is chosen to allow deflection of. In particular, the astigmatism characteristics are chosen to produce under convergence of the beam along the horizontal axis and over convergence of the beam along the vertical axis. This particular axis of convergence results in the actual coowner convergence of the beam described in Figure 3b.

The effect of coma, i.e., non-sized chrominance stripes, increases as the space between the electron beams increases and the picture tube screen size increases. If the diagonal length of the screen does not exceed 14 inches (35.6 cm), no correction for coma is necessary. As the water pipe screen diagonal increases, the effect of the coma increases proportionally, and therefore, it is necessary to use the coma shielding device described in FIG. 5 (a). Although toroidal yokes have been described in the above embodiments, suitable deflection yokes using saddle coils may also be used. The coma characteristics of the saddle coil can be controlled by the distribution of the saddle winding at the inlet and the middle of the coil. The similar astigmatism of the saddle coil can be controlled by the distribution of windings in the middle and outlet portions of this deflection bean. In some cases the coma shield described in FIG. 5 can be omitted because the coma characteristics of the saddle-shaped yoke can be controlled.

6 illustrates an aperture mask and linear phosphor element screen arrangement suitable for use in the water tube of FIG. The combination of the linear mask and the mold provides more light output than the dot screen mask array. 3, the three electron beams 20a, 20b, and 20c are red and blue of the line tongue applied to the screen 12 through the long aperture slit 15 in the aperture mask 14. And green phosphor elements. This type of coupling, in which the slit aperture is collinear with the vertical phosphor element lines, is advantageously used with the horizontal in-line electron gun described in FIG. 5 (a). The long slit aperture 15 in the aperture mask 14 passes more beams than the dot aperture used for the screen with dot phosphor elements. More mask transfer results in the long slit aperture vertical hollow element arrangement of FIG. 6 are to increase the light output of the water tube.

Unlike dela guns, the in-line gun used in the present invention does not require dynamic convergence and thus beam trio degrouping, ie beam trio as the beams are deflected from the center of the last. It does not cause the expansion of the spacing. Therefore, the lens arrangement for printing the phosphor elements becomes hard.

Another advantage of the present invention is that it provides improved sharpness and convergence of the screen edges by the absence of the shielded distortion caused by such internal devices.

The system also does not require a dynamic boat for misconvergence and coma effects. Since miss convergence and coma effects increase with increasing screen size, the present invention can be used well with in-line color water tubes with screen diagonal lengths of 23 and 25 inches (about 58.4 cm and 63.5 cm). In this case, however, this self-convergence characteristic may be corrected with a simplified dynamic convergence device. Such a scheme may use electrostatic or electronic convergence devices that are placed in the neck of the receiver and run only at one of the line and feed scan ratios. For example, by using only the horizontal dynamic convergence correction device with the horizontal in-line electron gun described above, it is possible to establish a raster in which the beams are satisfactorily concentrated at all points.

Claims (1)

The evacuated glass sealing tube 11 and the three different kinds of colored phosphor stripes form a vertically repeating pattern, vertically aligned to match the phosphor stripes on the screen 12 and the phosphor stripes on the screen 12. A shadow mask 14 in the glass encapsulation tube 11 having a plurality of elongated slit-shaped openings, and a glass encapsulation tube opposite the screen line 12 to generate three horizontal in-line electron beams. (11) a cathode ray tube composed of an electron gun (16) installed in the neck portion and which does not contain a dynamic convergence device at all: to concentrate the three beams at one point in the center portion of the screen (12). With a static convergence device 18 installed around the electron gun 16 to generate a magnetic field in the neck portion of the electron gun 16: a tube for deflecting while concentrating substantially the beam in the vertical and horizontal directions. A horizontal coil that generates a variable nonuniform deflection magnetic field along the longitudinal axis of the beam and generates a pure negative isotropic astigmatism that acts on the beam in the horizontal axis direction, and generates a nonuniform deflection magnetic field along the horizontal axis of the tube. In a self-conveying color image display system consisting of a deflection coil (17) with a vertical coil that produces pure positive isotropic astigmatism acting on the beam, at least two from the right end of the electron gun (16) that the electron beam emits. The electron gun 16 includes two adjacent common electrodes G3 and G4 so that the outer two of the three apertures of the common electrode G4 of the two common electrodes G3 and G4 are adjacent to each other. Self-converging color image display system characterized by a difference outward from the relevant apertures of (G3).

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