JPH06267456A - Color television display device - Google Patents

Abstract

PURPOSE: To obtain initial concentration even if the tube axis of an image tube and the center axis of a deflection yoke are slightly non-aligned by providing a deflection yoke for producing a horizontal magnetic field having a particular horizontal magnetic field distribution function. CONSTITUTION: A deflection yoke 16 is constructed by combining a hybrid type and a troidal type, and a horizontal deflection winding wire 20 having the winding wire 22 of an electron beam exit end is provided. A vertical deflection winding wire 28 is wound around a magnetic core 26 in a troidal shape. An insulator 18 provided between the horizontal deflection winding wire 20 and the vertical deflection winding wire 28 maintains the mutual positions of both winding wires and makes it easy to attach a yoke 16 to an image tube 10. Thus, for the horizontal and vertical deflection winding wires 20 and 28, even if the deflection yoke 16 is moved vertically or horizontally with respect to the tube axis of the image tube 10 or inclined, no substantial change occurs in the degree of concentration, and thus a gap 32 exceeding necessary machine assembling tolerance is not necessary at all between the yoke 16 and the image tube 10. Therefore, power consumed for deflection is greatly reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-focusing color television display which does not require precise adjustment of alignment or tilt between the x and y axes of a deflection yoke of a picture tube and the x and y axes of an electron gun. Regarding the device.

[0002]

2. Description of the Related Art A color picture tube forms a color image by causing electrons to collide with phosphors which emit light having different wavelengths. The phosphors that normally emit red, green, and blue light are used, and the phosphors are grouped into three groups each including three regions each containing one of the three colors.

In the picture tube, the phosphors of each of the three colors are excited by the electron beams that are made to impinge only on the phosphors of that color, and therefore each electron beam is identified by the color emitted by the phosphors that it excites. To be done. The area of impact of each electron beam is large compared to the area of the triad of phosphors, and each beam at any position on the display screen will have phosphors of each particular color in several triads. To excite.
The three electron beams are generated by three electron guns provided in the neck portion of the picture tube facing the display screen formed of the phosphor. The three electron guns are oriented such that the undeflected electron beam emitted from them follows a concentrated path towards the display screen.

In order for the display screen to provide a faithful color reproduction of the scene, the position of the beam relative to the picture tube must be adjusted to achieve color purity and static beam concentration at the center of the display screen. To control the color purity, the red, green, and blue electron beams excite only the phosphors of the respective colors, which is performed by the shadow mask. This shadow mask is in the form of a screen or a grid having a large number of apertures through which the electron beam can pass, and the apertures are located at fixed positions with respect to each of the three groups of color phosphor regions. Illuminates the phosphor of the appropriate color depending on its direction of incidence through one or more of its apertures. Color purity depends on the accuracy of the placement of the phosphor triad with respect to the aperture and the apparent electron beam source.

Static focusing refers to focusing the three beams at one scanning point at or near the center of the display screen. The concentration at the center of the display screen is attached to the neck of the picture tube, using a static concentration structure that is adjusted or excited to generate a static magnetic field to concentrate the three beams at the center of the display screen. It can be carried out.

To form a two-dimensional image, the emission points on the display screen excited by the three concentrated electron beams are scanned both horizontally and vertically across the display screen to form an emission raster area. There is a need to. This is done by the magnetic field generated by the deflection yoke mounted on the neck of the picture tube. The deflection yoke deflects the electron beam by substantially independent horizontal and vertical deflection systems. The horizontal deflection of the electron beam is mainly performed by a yoke ring that forms a magnetic field having vertical magnetic field lines. The strength of this magnetic field varies with time at relatively high frequencies. The vertical deflection of the electron beam is performed by a coil which produces a time-varying, mainly horizontal magnetic field at a relatively low frequency. A magnetically permeable magnetic core is provided on the yoke coil. The conductor of the coil may surround the magnetic core to form a toroidal deflection winding, or it may form a saddle coil that does not surround the magnetic core.

The display screen of the picture tube is relatively flat,
The electrons of each electron beam travel a longer distance when going to the edges of the display screen than when going to the center. Since the three electron guns are separately provided, when the three beams are deflected toward the edge of the display screen, the irradiation points of the respective beams may be separated. Also, with the nearly uniform deflection field of the prior art, the electron beam may become over-concentrated when deflected outward from the center of the display screen. These effects are combined to separate the light spots of the three beams at a point away from the center of the display screen. This is a known poor concentration and causes color edging around the displayed image. This concentration failure is allowed to some extent, but one in which the three irradiation points are completely separated is not allowed.

Concentration failure can be measured as the deviation from perfect alignment of the red, green and blue lines in the crosshatch pattern of the lines produced on the display screen when an appropriate test signal is applied to the picture tube. Since the three electron beams scan the rasters identified by their respective colors, an in-line image in which the central electron beam excites the green phosphor and the outer electron beams excite the red and blue phosphors, respectively. In the tube, the green raster is regularly scanned by the central electron beam and the outer beams scan the red and blue rasters. The cross-hatch pattern is formed by red, green, and blue rasters, including the vertical and horizontal lines that form the outline of the raster, and some other vertical and horizontal lines that pass through the center of the raster.

Previously, picture tube electron guns had a triangular or delta configuration. In this delta type electron gun system, as described in U.S. Pat. No. 3942067, a magnetic pole piece mounted around the neck portion of a picture tube and driven at a deflection frequency by a dynamic lumped circuit and provided in the neck portion. A dynamic concentrator including an additional concentrating coil that excites the electron beam concentrated the electron beam at a point away from the center of the display screen.

Recent television displays, as described in US Pat. Nos. 3,789,258 and 3,800,176, have a picture tube with an in-line electron gun assembly and a beam at substantially all points of the raster. A deflection yoke assembly having deflection windings that produce negative horizontal astigmatism and positive vertical astigmatism to be concentrated is used. This eliminates the need for a dynamic concentrator on the color television display. However, the degree of concentration becomes dependent on the position of the longitudinal axis of the yoke with respect to the axis of travel of the undeflected beam due to the non-uniform magnetic field that produces the axial astigmatism required for self-focusing. Because of this sensitivity, which affects the beam position in the tube, and normal manufacturing tolerances, it is necessary to adjust the yoke in a direction orthogonal to the axis of travel of the undeflected beam in order to obtain the best compromise. The magnitude of the change in concentration caused by the change in beam position with respect to the yoke axis is described in US Pat. No. 3,789,258.

Allows the deflection yoke to move (or tilt caused by laterally displacing the free end of the yoke) in a direction transverse to the electron beam in order to obtain the best overall concentration over the display screen. Therefore, the inside diameter of the conventional deflection yoke is slightly larger than the outside diameter of the corresponding portion of the envelope of the picture tube, for example, 2 to 6 mm.

While it is desirable to use as little material as possible in the construction of the deflection yoke, this requires that the deflection yoke be designed to fit snugly into the neck of the picture tube. Due to manufacturing tolerances, the design inner diameter of the deflection yoke should be larger than the nominal outer diameter of the video tube neck so that, in the worst case, the minimum inner diameter of the yoke will exactly fit the maximum outer diameter of the neck. With such a design, it is considered that the yoke fits substantially tightly to the neck portion even if there is a gap between the average inner diameter of the deflection yoke and the average outer diameter of the video tube neck portion.

According to such a tight fitting yoke, substantially all of the magnetic flux generated by the wire ring passes through the inside of the neck portion of the picture tube, but in the deflection yoke which is not tightly fitted, this and the picture tube. There is a magnetic flux passing through the gap with the neck of the. The magnetic flux outside this neck is not used for deflection, but only adds to the total energy stored in the yoke to provide a predetermined amount of deflection. This stored energy needs to be periodically replenished and removed from the deflection yoke, thus increasing the inductive scanning power, which is necessary for yokes that do not fit tightly into the neck of the picture tube. As a result, the yoke loss increases. Therefore, since the deflection yoke tightly fitted to the neck portion of the picture tube can be driven by the deflection circuit having a small inductive power supply, the power consumption of the yoke is small, and the display device is less than the loosely fitted yoke. The deflection sensitivity and reliability of are improved.

In the conventional self-concentrating deflection winding, it is necessary to adjust the position of the deflection yoke by moving it in the direction traversing the electron beam in order to obtain the required degree of concentration.
Therefore, it has been impossible to mass-produce the self-concentrating yoke that fits tightly to the neck portion of the picture tube.

Conventionally, various methods have been adopted for adjusting the position of the self-focusing yoke with respect to the beam to control the focusing degree. For example, as described in the above-mentioned US Pat. No. 3,789,258, first, a deflection yoke is attached to a picture tube and then static concentration adjustment is performed, and then the yoke is vertically and / or vertically adjusted to obtain the best concentration. It is moved horizontally, i.e. transverse to the electron beam, and is fixed in place by glue or other suitable fixing means. Such a yoke is tested on a standard picture tube at the time of manufacture, and it is previously assured that its characteristic is within a certain tolerance, that is, it is not a defective product.

In color television display devices recently produced by large corporations, the technique described in US Pat. No. 3,789,258 is used in two stages. In this method, the picture tube has the property that it can be individually adjusted by a standard deflection yoke at the final stage of manufacturing, and this adjustment sets the yoke positioning means at a predetermined position on the tube. This method also uses a pre-adjustable deflection yoke with position adjustment means. In addition, an adjustable circuit associated with the yoke can electrically compensate for the residual unmatched effects of the beam in the vertical deflection field. In this way, since each picture tube and each deflection unit are previously adjusted and adjusted separately, which picture tube and which deflection unit are automatically fitted,
Only push the deflection unit onto the neck of the picture tube until it stops and the end user does not need to make any adjustments.

However, it is desirable to eliminate the costly task of pre-adjusting each picture tube individually to the standard yoke. Further, it is not necessary to adjust the yoke to move or tilt the horizontal and vertical directions with respect to the undeflected electron beam in the picture tube.
It is desired to develop a self-focusing in-line electron gun television display device that can substantially concentrate the beam. Previously,
When deflecting the three electron beams, the differential deflection due to the non-uniform magnetic field necessary to obtain self-focusing, that is, the horizontal deflection action for one outer electron beam (for example, the blue electron beam) and the other outer electron beam ( The desired self-concentration was realized by deflecting with a slight difference in the horizontal deflection action on the red electron beam. In the past, it was believed that in such a non-uniform magnetic field deflection, the degree of concentration depends on the accuracy of matching the yoke magnetic field with respect to the vertical axis of the undeflected electron beam. For example, U.S. Pat. No. 4,060,836 describes that aligning the deflection magnetic field with each axis of the display tube is a condition for obtaining concentration without adding other means.

The magnitude of the concentration error as a function of the magnitude of the horizontal or vertical misalignment of the deflection yoke,
Specifically, the magnitude of the concentration error, which is expressed as a function of the magnitude of the deviation of the central axis of the deflection yoke with respect to the tube axis of the picture tube (or the central axis of the electron gun), separates the outer beams from each other on the display screen. Can be measured in units of mm, for example. By dividing the size of this concentration error by the size of deviation of the deflection yoke with respect to the tube axis or the central axis of the electron gun (also measured in mm), the concentration sensitivity can be obtained as a ratio without dimensions. The value represented is obtained. Therefore, it can be said that the smaller the concentration sensitivity, the smaller the concentration error due to the deviation of the deflection yoke.

The movement of the yoke in one plane may cause concentration errors at both ends in the two deflection directions. For example, if the yoke moves horizontally from the position where the best concentration is obtained, the width or error of the width of the red raster with respect to the blue raster is changed, and the height or height of both rasters is changed or error. Specifically, when the beam is horizontally displaced in the yoke field, the raster scanned by the leading beam, ie the beam displaced in the direction of displacement, becomes wider and taller than the raster scanned by the lagging beam.

Similarly, as the yoke moves vertically with respect to the tube axis of the picture tube, the lines formed by the outer beams of the horizontal and vertical crosshatch lines of the displayed center on the raster rotate in opposite directions. Cause crossover. In detail, when the beam is displaced upward in the yoke magnetic field (when the deflection yoke is displaced downward with respect to the tube axis), it is formed by the electron beam on the right side (when viewed from the display surface side or the exit side of the yoke). The center crosshatch line thus scanned rotates clockwise, and the center crosshatch line scanned by the electron beam on the left rotates counterclockwise.

On the contrary, when the beam is displaced downward in the yoke magnetic field (when the deflection yoke is moved upward with respect to the tube axis), the direction of rotation of the central crosshatch line formed by the electron beams on each side is changed. The rotation direction is opposite to the above.

With respect to some recent display devices, the magnitude of each concentration error when the deflection yoke is moved in a unit distance in the horizontal direction and the vertical direction with respect to the tube axis, that is, the concentration sensitivity (= concentration error / deflection yoke When the amount of movement) was measured, the results shown in Table 1 below were obtained.

[0023]

[Table 1]

Some conventional RCs that do not implement the invention
When the same measurement was performed on the device manufactured by Company A, the results shown in Table 2 below were obtained.

[0025]

[Table 2]

It is desirable that the concentration sensitivity with respect to the horizontal and vertical movements of the deflection yoke is 0.4 or less in any of the items, but in the conventional display devices shown in the above two tables, the concentration sensitivity is low. Even if the condition of 0.4 or less can be partially achieved, the concentration sensitivity cannot be 0.4 or less for all the items.

For example, in the Philips 20AX type and RCA XP74-125Q type display devices, a complete self-concentrating deflection yoke is not used, and the vertical concentration is dynamically concentrated. Since the convergence system is used, the vertical crossover error with respect to the vertical movement of the deflection coil is 0.3, which is relatively small. Specifically, in the 20AX type display device, the height error with respect to the horizontal movement of the deflection yoke and the vertical crossover error with respect to the vertical movement are both 0.3, which are below the allowable value. This is because the vertical astigmatism error is reduced by adopting the above dynamic concentration method. The 20AX type display device employs the dynamic concentration system as described above, and further, the width error and the horizontal crossover error are both 0.5, which exceeds the allowable value concentration sensitivity of 0.4. In the other display devices shown in the above table, the concentration sensitivity of each concentration item cannot be set to the allowable value 0.4 or less.

The dimension calculation of the self-concentrating deflection yoke is performed by the third-order aberration theory as follows. Philips Research Report (Ph
ilips Research Reports) 1975 Volume 12 No. 46-
68 and 1959, Vol. 14, pp. 65-97, J. Haantjes and G. Lubbe.
n) two papers "Errors of Magneti Deflection (Errors of Magneti
c Deflection) ”, the third-order aberration theory of magnetic deflection is used to approximate from the magnetic field distribution functions H ₀ (z) and H ₂ (z) of the yoke that change with the position along the longitudinal axis of the yoke, that is, the Z axis. Electron optical performance can be analyzed. The symbol system used in the following analysis is based on the above paper.

Deflection of the electron beam considering only H ₀ (z), which is the main component of the deflection magnetic field, is called Gaussian deflection and is represented by X or Y. To display the magnetic field more completely, H ₂ (z) representing the nonuniformity of the yoke magnetic field across the electron beam is used. Although the explanation of the yoke magnetic field by the magnetic field distribution functions H ₀ (z) and H ₂ (z) cannot be applied accurately when the total deflection angle is 75 ° or more, the tendency obtained from the explanation about this yoke deflection magnetic field is It is also useful when outlining the performance of magnetic deflection systems with wider deflection angles such as 90 ° and 110 °.

Hahnchez and Leuven in the above paper present a general theory and a pure mathematical analysis of self-concentrating deflection yokes, ie deflection yokes with low concentration sensitivity to concentration error. The inventor of the present application has reorganized a part of the theory described in the above paper in a form corresponding to the actual situation to determine the necessary conditions for actually designing a manufacturable deflection yoke with low concentration sensitivity. We have derived a valid formula.

Equations (1) to (22) described below are derived from the above viewpoints based on the equations and the theory shown in the papers of Hahnchess and Leuven. The deflection magnetic field is represented by the following power series expansion of the electron optical axis of the yoke. That is, the horizontal plane (y
= Horizontal deflection magnetic field in 0) is a _{H IIy = H IIO (z)} + H II2 (z) x 2 (1), wherein the yoke axis along the Z axis of the coordinate system, the vertical plane (x
The vertical deflection field in (= 0) is H _IX = H _IO (z) + HI ₂ (z) y ² + (2). The subscript I represents a vertical deflection magnetic field whose main component is in the X direction, and the subscript II represents a horizontal deflection magnetic field whose main component is in the y direction.

In the general aberration display method, the differences Δx and Δy on the display surface between the Gaussian deflection and the third-order deflection (that is, considering the H ₂ (z)) are described. In the case of a picture tube having an in-line type electron beam, the display for y is simplified by eliminating the term relating to the entrance end of the beam entering the yoke magnetic field at an inclination other than the horizontal plane.

In the case of an in-line type electron beam, the expression for displaying aberrations which is suitable for the present invention is as follows.

[Equation 1] Where X _S and Y _S are Gau deflection on the display screen, x _S 'is the tilt in the horizontal plane of the beam entering the yoke magnetic field, and X _S and Y _S are the undeflected beams measured from the traces of the yoke axis on the display screen. Is the coordinates of the irradiation point. Expressions (3) and (4) are only a part and include only terms related to the present invention, that is, upper and lower pincushion distortion, concentration (astigmatism and coma), and concentration sensitivity of concentration.

Aberration coefficients A ₃ , A ₄ , A ₆ , A ₇ , A ₁₆ ,
A ₁₈ and _{B 2, B 5, B 6} , B 8, B 17, B 18 can be represented by the integral form. The physical importance of this aberration coefficient can be easily understood by making the following assumption for simplicity. (1) The main deflection magnetic fields of the vertical and horizontal _coils are the same, that is, H _IIO
(z) ≈−CH _IO (z), and (2) their Gaussian deflections are substantially coincident and X≈CY (scale coefficient difference C ≠ 1.
Does not affect the aberration coefficient, including the ratio of the magnetic field distribution function). This is very similar to a toroidal type yoke in which the axial length of each vertical and horizontal winding is equal, and in the case of a saddle type or saddle type-toroidal type winding, the shortening of the length of the vertical coil is compensated by the increase of the inner diameter. And the approximation is saved. The details of the winding distribution in the horizontal and vertical windings are different, so their non-uniformity functions are not the same. That is, H _II2 (z) ≠ −CH _I2 (z). Therefore, simplified aberration coefficients necessary for understanding the present invention are as shown in the following equations (5) to (14).

[0035]

[Equation 2]

Here, D is the distance from the main surface of the Gaussian deflection to the display screen, L is the effective length of the deflection yoke, and λ = L /
D, S ₁ , S ₂ , S ₃ , and S ₄ are as defined below.

The terms S _IIi and S _Ii (i = 1, 2, 3, 4) are integral notations including the functions H _IIO , H _II2 , H _IO , and H _I2. 15), coefficient B ₂ + A _{3 of} equations (4) and (5) including both terms represented by (16)
Depends on.

[0038]

[Equation 3]

Where X _S and Y _S are the deflection centers of the yoke z _C
Is a Gaussian deflection on the display screen at z _S at a distance D = (z _S −z _C ), where z is the distance measured along the vertical axis of the yoke. H _II2 and H _I2 are inhomogeneity functions of horizontal and vertical magnetic fields, respectively. The integration is officially from -∞ to +
It should be done up to ∞, but in practice it is sufficient to start from a position approximately equal to the diameter of the yoke from the entrance of the yoke and end at the display screen.

The astigmatism in the horizontal direction is determined by the coefficient A ₄ , which is partially determined by the following equation (17).

[Equation 4] The astigmatism in the vertical direction is determined by the coefficient B ₅ , which is partially determined by the following equation (18).

[Equation 5] Coma aberration is determined by the following equations (19) and (20).

[Equation 6]

These notations represent pincushion distortion, astigmatism, and coma that were considered in the prior art to form a self-focusing yoke with upper and lower pincushion distortion and coma aberration corrected.

The concentration sensitivity is expressed by the following equations (21) and (22).

[Equation 7]

While all parts of the yoke and its magnetic field affect their respective strains, the effects of changes in certain areas of the magnetic field can disproportionately affect a particular strain.

According to the present invention, the portions corresponding to the entrance area, the central area, and the exit area of the H ₂ function, which will be described later, are respectively related to the sensitivity of the concentration degree to the misalignment of the deflection yoke with respect to the picture tube of the display device. It was constructed with the recognition that it has different influences. York magnetic field 3
The area is divided into the area from the exit of the electron gun to the vicinity of the entrance surface of the horizon, the exit area from the vicinity of the exit surface of the magnetic core to the display screen, and the central area from the entrance surface to the exit surface.

The weighting function that appears in the integrand of S _IIi and S _Ii weights the H ₂ function as shown in FIG.
Assuming similar main deflection fields, the vertical magnetic field weighting functions are corresponding, so only the horizontal weighting function need be shown. In FIG. 1, the horizontal axis represents the axial distance in the display system measured from the deflection center z _C , and the vertical axis represents the weighting function in arbitrary units.
The display screen is located at z _S = 25.4 cm from the center of deflection. The approximate positions of the entrance face and the exit face of the deflection yoke are indicated by EN and EX, respectively. The ordinate changes if the function changes.

In equations (15) and (16), the values of the negative weighting functions X ² (z−z _S ) and Y ² (z−z _S ) appearing in both equations as shown in FIG. Since it rises very rapidly from a low value, it indicates that the pincushion distortion is mainly determined by the action of the H ₂ function in the exit region and less affected by the H ₂ function in the central region.

Equations (17) and (18) are positive weighting functions X
Since (z−z _S ) ² and Y (z−z _S ) ² rise rapidly from the value at the entrance, the astigmatism required for self-concentration is determined by the H ₂ function in the center and exit regions of the yoke. Is shown.

In equations (19) and (20), the value of the negative weighting function (z−z _S ) ³ rapidly decreases from its maximum value at the entrance, so that the coma aberration is mainly of the H ₂ function in the entrance region. It is determined by the action, and the central region is less affected by the H ₂ function.

The equations (21) and (22) show that the positive weighting function (z−z _S ) ² drops slowly from the maximum at the entrance, so that the concentration sensitivity to deflection yoke misalignment is mainly in the entrance region and the center. It is shown that it is determined by the action of the H ₂ function in the region and less affected by the H ₂ function in the exit region.

The horizontal deflection magnetic field distribution of all toroidal deflection yokes used in the RCA horizontal in-line electron gun and 17V 90 ° deflection television display shown in Table 2 is shown in FIG. The magnetic field distribution is shown in FIG. Further, FIG. 3A shows the horizontal deflection magnetic field distribution of the horizontal toroidal electron gun manufactured by Hitachi and the semi-toroidal deflection yoke used in the 17V 90 ° deflection television display shown in Table 1 above. Is shown in FIG. 2 (a), 2 (b), 3 (a), 3 (b)
As shown in, the H _I2 and H _II2 functions are multiplied by 10 to make their features clear.

When discussing the characteristics of the deflection yoke used in the conventional television display device, in addition to FIGS. 2 (a), 2 (b), 3 (a) and 3 (b), FIG. It can be based on the weighting function shown in 1. Such a yoke had a non-uniformity function H _II2 of the horizontal magnetic field in which the positive lobe (pincushion distortion type magnetic field) had an excessively large peak near the entrance EN of the yoke. Since the pincushion-type magnetic field near the entrance of the yoke, where the deflection is still small, must have excessive inhomogeneity to achieve self-concentration, such an H _II2 function requires a negative concentration of the offset beam along the horizontal axis. The efficiency of producing the astigmatism was poor. This inefficient axial distribution of the H _II2 function shown in FIGS. 2 (a) and 3 (a) resulted in concentrated sensitivity to beam misalignment in a horizontal magnetic field, causing horizontal coma.

[0052]

The vertical magnetic field non-uniformity function H _I2 of the above-mentioned conventional deflection yoke has a very large negative value (barrel magnetic field) near the entrance of the yoke, and in the case of a toroidal vertical coil. All became negative imbalances or single-rope H _I2 functions as shown in FIGS. 2 (b) and 3 (b).
The effect of the barrel-shaped magnetic field in the entrance area of the yoke on the astigmatism is small, so that the barrel-shaped magnetic field in the central area of the yoke comes to have excessive non-uniformity for achieving self-concentration.
Such a H _I2 function did not efficiently produce the positive astigmatism required for self-focusing along the vertical axis. Thus, FIG.
Due to this inefficient axial distribution of the H _I2 function shown in (b) and FIG. 3 (b), a considerable amount of vertical coma is generated, which results in a high concentration for electron beam misalignment in a vertical magnetic field. There is a problem that it exhibits sensitivity and further causes upper and lower pincushion distortion. It was difficult to correct this upper and lower pincushion distortion without causing gullwing distortion in the upper and lower parts of the raster, that is, distortion of a frequency higher than the horizontal frequency.

According to the present invention, the deflection yoke is tightly fitted to the neck portion of the picture tube without the need for position adjustment in one or both of the horizontal direction and the vertical direction across the electron beam or pre-adjustment. It is an object of the present invention to obtain a color television display device having a self-concentrating deflection yoke which has substantially no concentration sensitivity.

[0054]

A color television display device according to a preferred embodiment of the present invention includes a video tube including an electron gun assembly for generating a plurality of in-line electron beams in a neck portion facing a display screen, and a video tube thereof. A deflection yoke attached to the neck for deflecting the electron beam to form a raster on the display screen. The yoke has a magnetic core and vertical and horizontal deflection windings, each producing a magnetic field with positive and negative on-axis astigmatism for substantially focusing the beam at all points of the raster. This deflection field reduces the relative dimensional change on each side of the raster formed by the outer beams of the plurality of beams, thus reducing the peak of nonuniformity change.

This deflecting magnetic field also gives the relative displacement of both ends of the horizontal and vertical crosshatch lines that are scanned by the outer beam through the center of the raster when the deflection yoke is moved transversely to the beam. When the deflection yoke is moved by 1 mm in the direction traversing the beam, it is possible to reduce the concentration sensitivity to less than 0.4 mm, that is, the concentration sensitivity to 0.4 or less.

[0056]

According to the present invention, the astigmatism deflection magnetic field necessary for self-focusing can be obtained by the deflection yoke having the winding that does not pass the shortest path (geodetic curve) between two points on the inner surface of the wheel. In addition, the coma aberration and the vertical pincushion distortion can be reduced, and at the same time, the degree of concentration affects the alignment error between the central axis of the deflection magnetic field of the yoke and the central axis of the picture tube or the undeflected electron beam. Is not received, that is, a deflection magnetic field with low concentration sensitivity is generated.

This yoke balances the minimum inhomogeneity of the horizontal and vertical magnetic fields required for self-concentration and vertical pincushion distortion in the central and outlet regions of the yoke with the opposite inhomogeneity of the yoke inlet region to reduce coma. And minimizes the concentration sensitivity to beam misalignment in the deflection field.
In particular, the horizontal H _II2 function has a positive part smaller than that of the conventional one in the central region, and the peak value occurs near the exit end. This axial distribution of the H _II2 function is efficient because it produces the negative horizontal astigmatism required for self-focusing at the low peak value of the non-uniformity function of the horizontal pincushion type magnetic field.

In the following, while avoiding a complicated description, an ideal deflection yoke having no concentration sensitivity, that is, a horizontal deflection winding having a predetermined H _II2 function and a predetermined H _I2 function will be described. The following describes a deflection yoke that is a combination of a vertical deflection winding and a vertical deflection winding.However, the horizontal deflection winding and the vertical deflection winding described here are used in combination with other vertical deflection windings and horizontal deflection windings, respectively. However, it goes without saying that the horizontal deflection winding having no concentrated sensitivity and the vertical deflection winding having no concentrated sensitivity can be obtained.

[0059]

BEST MODE FOR CARRYING OUT THE INVENTION In a deflection yoke embodying the present invention, in order to minimize the concentration sensitivity to beam misalignment in the yoke magnetic field and to substantially eliminate horizontal and vertical coma aberrations and raster up and down pincushion distortion, The non-uniform function of the magnetic field generated by the deflection yoke satisfies the four requirements expressed by the following equation.

(1) In order to minimize the upper and lower pincushion distortion, it is desirable to set (B ₂ + A ₃ ) in the equation (4) to 0.
Therefore, the following equation is obtained from the equation (5),

[Equation 8] Therefore,

[Equation 9] Thus, the upper and lower pincushion distortion can be minimized.

(2) The magnitudes of the negative horizontal astigmatism and the positive vertical astigmatism required for self-focusing are determined by A in the equation (3).
_{In order to set 4} and B ₅ to A ₄ ≈0 and B ₅ ≈0, from equations (6) and (7)

[0062]

[Equation 10] It is obtained by

This condition A ₄ = B ₅ ≈0 is also used as an approximation in the case of a large screen display device. In this case, in order to minimize A ₆ + B ₆ in the equation (4), A _{4 is set} to a small negative value and B ₅ is set to a small positive value (insufficient concentration along the horizontal axis, Over-focus along the way, thereby gaining substantial concentration over the entire raster).

(3) Coma distortion can be removed by setting A _{7 in} the equation (3) and B ₈ in the equation (4) to A ₇ = 0 and B ₈ = 0. Therefore, the following equations (26) and (27) are obtained from the equations (9) and (10).

[Equation 11]

(4) In order to make the concentration sensitivity to horizontal misalignment substantially zero, A ₁₆ and B ₁₇ in the equation (3) are changed to A ₁₆
= 0 and B ₁₇ = 0. Therefore, the formula (1
According to 1) and the equation (13), S _II4 = 0 (28) and S _I4 = 0 (29).

Further, in order to make the concentration sensitivity to the vertical misalignment substantially zero, A ₁₈ and B ₁₈ in the equation (4) are changed to A ₁₈ =
It is necessary to set 0 and B ₁₈ = 0. Therefore, from equation (12) and equation (14)

[Equation 12] Becomes

However, S _II4 and S _I4 are both 0 at the same time,
Because it cannot be 1 / 2D,

[Equation 13] By doing so, the concentration sensitivity for both horizontal and vertical misalignment can be set to the minimum allowable value.

These six equations (23), (24), (25),
(26), (27) and (32) show the minimum H ₂ magnetic field produced by the new deflection yoke of the present invention (the H ₂ function which exhibits the minimum concentration sensitivity to movement of the deflection yoke across the electron beam). Magnetic field). Given the function given, H _II0 = -CH _I0 , these six equations constitute a set of linear integral equations whose solution is the minimum H ₂ magnetic field function generated by the yoke according to the invention.

H of the deflection yoke according to one embodiment of the present invention
Figures 4 (a) and 4 (b) are diagrams of the ₀ function and the H ₂ function.
Shown in. In the yoke embodying the present invention, as can be seen from FIG. 4 (a), the nonuniformity of the barrel-shaped magnetic field in the central region of the vertical wire loop is small, so the vertical pinwheel distortion due to the vertical wire loop is smaller than that of the conventional yoke. This reduces the non-uniformity of the pincushion magnetic field at the center of the yoke of the horizontal wheel, but spreads over a wider area toward the display screen as shown in FIG. 4 (b) to correct upper and lower pincushion distortion. In this way, since the inhomogeneity of both the horizontal and vertical magnetic fields decreases from the center to the exit region, self-concentration is achieved which is virtually insensitive to the beam position with respect to the magnetic field.

FIG. 5 shows the picture tube 10 and the deflection yoke 16. The picture tube 10 has a neck portion 12 connected to a morning glory valve portion 14 which is enlarged toward the front, and an electron gun assembly 13 (shown by a block) attached to the neck portion 12 has an in-line type electron in the picture tube 10. Generate a beam. The deflection yoke 16 is a hybrid type, that is, a combination of a saddle type and a toroidal type, and has a horizontal winding 20 having a winding 22 at the electron beam exit end. The vertical deflection winding 28 has a magnetic core 26.
It is wrapped in a toroidal shape. The insulator 18 between the horizontal winding 20 and the toroidal vertical winding 28 maintains the mutual positions of both windings, and the yoke structure is attached to the picture tube 10.
To provide a means (not shown) for attachment to the.

According to the present invention, the windings 20 and 28 have a high degree of concentration regardless of whether the yoke 16 is moved vertically or horizontally with respect to the tube axis of the picture tube 10 or the yoke 16 is inclined. It is configured so as to be substantially unchanged. Therefore, the gap 32 between the yoke 16 and the picture tube 10 does not require more than the required mechanical assembly tolerance. As a result, the yoke of the tube is substantially impossible to move in the vertical or horizontal direction with respect to the tube axis of the picture tube 10, and similarly, the yoke is not substantially tiltable with respect to the tube axis. It can be configured to fit snugly on the part.
Therefore, the yoke of the present invention requires less material than a conventional yoke having a large gap 32.

In the structure shown in FIG. 5, a larger amount of magnetic flux generated by the yoke can be used for deflection than the conventional one, so that a predetermined electron beam deflection magnetic flux density can be obtained in the picture tube neck portion with a smaller current than the conventional one. The result is that the deflection sensitivity is increased, the energy circulation between the yoke and the drive circuit is reduced, and the total power consumed for the deflection is very small.

As is well known, among the conductors of the vertical and horizontal windings, only the conductors along the inner circumference of the magnetic core of the deflection yoke have a great influence on the deflection. Therefore, the winding distribution exhibiting the advantage of the present invention is a toroidal type. Any type of saddle type winding can be obtained.

FIGS. 6 (a) and 6 (b) respectively show horizontal and vertical deflection winding distributions of the yoke embodying the present invention as seen from the enlarged beam exit end of the deflection yoke. Although the inlet ring is made large for easy viewing, it is difficult to understand the distribution near the beam inlet end from this figure.

FIGS. 7 (a) to 7 (c) are diagrams showing two quadrants of respective winding distributions in the inlet end region, the central region and the outlet end region of the horizontal winding of the yoke shown in FIG. 6 (a). 7 (d) to 7 (f) are views showing the respective winding distributions in the inlet end region, the central region and the outlet end region of the vertical winding of the yoke shown in FIG. 6 (b) in two quadrants.

In FIG. 7A, areas 300 and 302 are provided.
Indicates a region where windings are distributed near the entrance end of the yoke. The straight lines 304 and 306 represent the centers of the actual winding distribution, not the graphic centers (volume centers) of the regions 300 and 302, respectively. As shown in FIG. 7A, the winding distribution 302 is 70 °.
Opposite the central angle of the winding distribution, the center 304 of the winding distribution itself lies 35 ° from the horizontal plane, which indicates that the actual winding distribution is symmetrical about this center 304. Similarly, in FIG. 7B showing a cross section near the central region of the yoke, a region 310 shows a region in which the horizontal windings are distributed. The regions 310 face the central angle of 53 ° and start from the horizontal plane. There is. Line 312 shows the central angle of the winding distribution occurring in region 310, which is located 27 ° above the horizontal, which indicates that the winding distribution in region 310 is almost symmetrical. ing. However, there is no indication of whether the distribution is concentrated at the ends of region 310, is evenly distributed over the whole region, or has a different distribution.

Similarly, FIG. 7C shows the winding distribution in the vicinity of the outlet area of the yoke occupying the area 324 facing the central angle of 24 °. The figure center of this winding distribution is 12.5 from the horizontal plane.
° Raised position. The winding distribution in region 324 is not symmetrical, but the actual distribution situation is not shown. FIG. 7D shows the vertical winding distribution in the region 334 near the entrance end of the yoke. Each of these areas 334 has a central angle of 5
It is facing 8 °. The center of each winding distribution is 2 from the vertical axis
Located at 4 °, this is not the center of region 334.
Similarly, FIG. 7 (e) shows a region 344 with vertical winding distribution near the central region of the yoke. Each of these regions 344 begins at 6.6 ° from the vertical axis and opposes a central angle of 68 °. The graphic center of the winding distribution of each region 344 is on the straight line 342 at 36.5 ° from the vertical axis, and is not near the center of the region 344. FIG. 7F shows a region 3 near the outlet end of the yoke.
54, the figure center 352 is the winding distribution area 35.
It is near the center of 4. From FIGS. 7A to 7F, it is clear that more detailed description is necessary to properly explain the details of the winding distribution.

FIG. 8 shows a method of displaying two winding distributions according to the present invention. 8 (a), (c), (e), (g),
(I) and (k) are actual conductor distributions, (b), (d),
(F), shows a (n), (j), (m) is wound density distribution derived from the conductor distribution W _H, W _V. The horizontal axis of FIG. 8 represents one quadrant of the periphery of the yoke, and this quadrant is divided into 41 equal sections each having a number. These compartments represent the actual channels on which the wire can be laid or the feed points where the winding machine winds the wire. The symbol 0 at the left end of the horizontal axis represents the end of one quadrant and the beginning of the illustrated quadrant, and the symbol 41 at the right end represents the end of the illustrated quadrant and the beginning of the next quadrant.
The angle of each section is also shown. The conducting wire arranged on the 0 axis is shown by a half-dotted line and a half solid line, showing that half of this conducting line contributes to the magnetic field distribution in the quadrant in question. Although the conductors are shown vertically and horizontally separated in the figure, they are actually closely wound.

The conductor shown in FIG. 8 is a cross section of the conductor forming a toroidal or saddle type winding, so that the same current flows through all conductors. 8 (a) and 8 (b) show the horizontal winding distribution near the outlet end of the yoke embodying the present invention. For this purpose, the outlet end is at or near the end of the magnetic core. The conductors 402 and 404 are located above the zero point on the horizontal axis which corresponds to a break between quadrants in FIG. 8A. For the purpose of analysis, it is assumed that each of them flows 1/2 of the unit current, and therefore acts as 1/2 of the winding in the quadrant shown, that is, 1 winding in total. There is also a third conductor 406 in the first section of the quadrant of FIG. 8 (a), which is completely within the first section and thus corresponds to one complete turn. The action of the winding is also such that the conductor wire 40 spanning the boundary line between the first section and the second section of the quadrant.
7, 408, but these conductors 40
7 and 408 each act as a 1/2 turn, and a total of 1 turn. Therefore, the total number of working turns in the first section of the quadrant of FIG. 8A is 1 for the conductive wires 402, 404, 407, and 408, respectively.
/ 2 units and the conductive wire 406 is 1 unit, for a total of 3 windings.
FIG. 8B shows that the total number of action windings in the first section of this quadrant is three.

The second section of the quadrant of FIG.
7 and 408 each 1/2 turn, each half of the conducting wires 411 and 412 that cross the boundary between the second section and the third section, and each 1 turn of the windings 409 and 410. The total number of action windings is 4 as shown in FIG. 8 (b). Figure 8
The number of working windings in the third section of (a) is also 4, but the number of working windings from the fourth section to the eleventh section is 3 each.
The twelfth section receives the action of 1/2 unit from the windings 414 and 416, respectively, and the total number of action turns is 1, as shown in FIG. 8 (b). The remaining section of this quadrant has no conductor and the number of working turns is zero. Thus, the actual winding distribution of the yoke shown in FIG. 8A can be represented by the discontinuous winding density distribution function W _h 420 as shown in FIG. 8B.

FIG. 8 (c) shows an actual horizontal winding distribution in one quadrant in the central region between the inlet end and the outlet end of the yoke embodying the present invention, and 440 in FIG. 8 (d) shows that winding. A winding density distribution function (W _h ) representing the net action winding number of the wire
Indicates. Similarly, the winding distribution of FIG. 8E shows the horizontal winding distribution near the inlet end of the yoke embodying the present invention.
460 of (f) shows the winding density distribution ( _Wh ).

The vertical winding distribution (W _V ) of the yoke embodying the present invention is shown in FIGS. FIG. 8 (g),
(I) and (k) show the actual vertical winding distributions at the inlet end, central region, and outlet end of the yoke,
(H), (j), (m) show the corresponding vertical winding density distribution functions (W _V ) 470, 480, 490. Figure 8 (a)
7- (c) are compared with FIGS. 8 (g)-(f).
Comparing (m) with FIGS. 7 (d)-(f), the winding distribution representation of FIG. 7 is a little oversimplified in that important structural details about winding distribution have been omitted. It is understood that there is.

Mathematical characterization of the yoke wheel is known and can be done by Fourier expansion of the winding distribution as described in US Pat. No. 4,117,434. That is, for a particular cross section of the yoke, the individual winding distribution of the horizontal and vertical loops of the yoke according to the invention can be represented by the Fourier series expansion of its respective winding density.

[0084]

[Equation 14]

Here, C _n and S _n are odd-order Fourier coefficients of the horizontal and vertical winding density distributions respectively, W (φ) is the winding density distribution, and W (φ) dφ is from φ to φ + dφ. It means the number of turns. The total number of turns N per quadrant (of course the same throughout all cross sections) is given by:

[0086]

[Equation 15]

The figure center (volume center) of the winding density distribution is

[Equation 16] And the angle θ between the center of volume of both halves of the wire ring is

[Equation 17] Note that

The yoke constructed according to the present invention is XP
75-125-CE 90 ° type yoke. The coil of the 90 ° -type yoke according to the present invention has three cross sections (inlet, center,
At the exit) is represented by the fundamental harmonic and the third harmonic of that winding density. In order to make this expression irrelevant to the impedance of the coil, the fundamental component is represented as part of the total number of turns in one quadrant and the third harmonic is represented as part of its fundamental component.

The coefficients in Table 3 below are the toroidal type 90 ° deflection yokes (XP75-125-CE) embodying the present invention.
2) shows the normalization coefficient of the fundamental harmonic and the third harmonic of the winding distribution at the inlet end, the central region and the outlet end.
This horizontal winding distribution is based on the fundamental component (C ₁ / N _H ) and the third harmonic component (C ₃ / C ₁ ), and the vertical winding distribution is based on the fundamental component (S ₁ / N _V ) and the third harmonic component. It is approximated by the component (S ₃ / S ₁ ).

[0090]

[Table 3]

FIG. 9 shows these Fourier coefficients at three axial positions along the yoke (inlet, center, and outlet).

Similarly, for the toroidal type 110 ° deflection yoke (XP75-128-EXQ) embodying the present invention, the wire ring is characterized by the coefficients shown in Table 4 below.

[0093]

[Table 4] This is shown in FIG.

In the yoke according to the present invention, the basic Fourier component C ₁ / N of the winding density standardized with respect to the total number of windings per quadrant whose winding distribution increases from the entrance end to the exit end of the yoke. _H , the third harmonic Fourier component C ₃ which has a negative value at the yoke entrance end but which turns positive in the central region or in front of it and has a positive maximum near the exit / C ₁ and a normalized fundamental Fourier component S ₁ / N _{V in} which the winding distribution decreases from the entrance end of the yoke to the exit end and a negative value at the entrance end of the yoke. , But with a vertical helix that is positively converted in or in the central region and characterized by a normalized third harmonic component S ₃ / S ₁ with a positive maximum near the exit end .

Concentrated sensitivity measurement values of these yokes (mm /
mm) is as shown in Table 5 below, and is substantially insensitive.

[Table 5]

For practical purposes, when the yoke is moved horizontally across the electron beam in the picture tube, or when the yoke is tilted, the vertical cross scanned by the two osset beams on either side of the raster. The hatch line is 0.4mm horizontally when the yoke moves 1mm.
Less than 0.4 mm / mm, and when moving the yoke vertically across the electron beam, the ends of the horizontal line scanned by the offset beam through the center of the raster must move less than 0.4 mm / mm relative to each other. It can be said that the horizontal deflection winding is not sensitive to its movement. Similarly, when the yoke is moved horizontally across the electron beam, the horizontal crosshatch lines scanned by the offset beams above and below the raster move vertically less than 0.4 mm / mm relative to each other, and the yoke Is moved vertically across the electron beam, the ends of the vertical line scanned by the offset beam through the center of the raster are horizontally offset by .0.
It can be said that the vertical deflection winding has no concentrated sensitivity if it moves less than 4 mm / mm.

The saddle yoke is also characterized by Fourier coefficients. The quasi-continuous winding distribution of a saddle type coil within one quadrant of the yoke is represented by a Fourier series expansion of its radial thickness in a constant Z plane representing one section of the winding.

T (φ) = ΣCn cos n φ Here, T (φ) is a thickness that changes according to the angle φ in an arbitrary cross section, and Cn is an nth-order Fourier coefficient. The area A of an arbitrary cross section perpendicular to the inner side R (z) of the saddle type wire wheel is constant because the total number of conductors in all cross sections is equal to (T) ²
<< R is expressed by the following equation.

[0099]

[Equation 18] Where R is the inner radius of the horizontal saddle type wire wheel in the cross section in question, R ′ = dR / dZ, and Z is the axial distance.

The horizontal saddle type wire ring is characterized by the Fourier coefficients of the fundamental harmonic and the third harmonic of its radial thickness in three defined cross sections. Similarly, since the impedance is standardized, the basic component of the cross-sectional area is expressed as a part of the total cross-sectional area corresponding to the standardization for the number of turns or the amount of winding, and the third harmonic component is the basic component. Represented as part of the ingredient.

Other embodiments of the present invention will be obvious to those skilled in the art. For example, the above-mentioned horizontal deflection winding without concentration sensitivity ((insensitive horizontal deflection winding) Vertical deflection winding) and conversely, a vertical deflection winding with no concentration sensitivity (insensitive vertical deflection winding) is used with a horizontal deflection winding with sensitive sensitivity (sensitive horizontal deflection winding). You can also

[0102]

According to the present invention, the degree of concentration is not affected by the alignment error between the center axis of the deflection magnetic field of the yoke and the tube axis of the picture tube or the center axis of the undeflected electron beam, and therefore As a result, it is possible to obtain a self-concentrating deflection yoke which does not require position adjustment or advance adjustment of the deflection yoke and which can be tightly attached to the picture tube and has no concentration sensitivity.

[Brief description of drawings]

FIG. 1 is a diagram showing a weighting function useful for explaining a region having a great influence on various deflection errors.

FIG. 2 is a diagram showing a deflection magnetic field distribution of an example of a conventional deflection yoke, (a) showing a horizontal deflection magnetic field distribution, and (b) showing a vertical deflection magnetic field distribution.

FIG. 3 is a diagram showing a deflection magnetic field distribution of another example of the conventional deflection yoke, in which (a) shows a horizontal deflection magnetic field distribution and (b) shows a vertical deflection magnetic field distribution.

FIG. 4 is a diagram showing a deflection magnetic field distribution of an embodiment of the deflection yoke of the present invention, (a) showing a vertical deflection magnetic field distribution, and (b).
FIG. 4 is a diagram showing a horizontal deflection magnetic field distribution.

FIG. 5 is a cross-sectional side view showing a state in which the deflection yoke of the present invention is attached to a picture tube.

FIG. 6A is a schematic end view of the horizontal deflection winding of one embodiment of the deflection yoke of the present invention as seen from the outlet end side, and FIG.
FIG. 3 is a schematic end view of the vertical deflection winding of one embodiment of the deflection yoke of the present invention as seen from the outlet end side.

7A to 7C are diagrams showing respective winding distributions in the inlet end region, the central region, and the outlet end region of the horizontal deflection winding shown in FIG. 6A in two quadrants. 6D to 6F are views showing respective winding distributions in the inlet end region, the central region, and the outlet end region of the vertical deflection winding shown in FIG. 6B in two quadrants.

FIG. 8 is a diagram showing winding distribution of an embodiment of the deflection yoke of the present invention, in which (a), (c), (e), (g), (i),
(K) shows the actual winding distribution, (b), (d),
(F), it is a diagram showing a (n), (j), (m) is wound density distribution derived from the winding distribution W _H, W _V.

FIG. 9 is a deflection yoke showing the normalized Fourier basic component and third harmonic component coefficient values of the winding distribution at the inlet end, the central region and the outlet end of the toroidal 90 ° deflection yoke according to the present invention. FIG. 5 is a diagram showing a function of the longitudinal position of FIG.

FIG. 10 is a deflection yoke showing the normalized Fourier basic component and third harmonic component coefficient values of winding distribution at the entrance end, the central region and the exit end of the toroidal type 110 ° deflection yoke according to the present invention. FIG. 5 is a diagram showing a function of the longitudinal position of FIG.

[Explanation of symbols]

 10 video tube 12 neck part 16 deflection yoke 20 horizontal deflection winding 26 magnetic core 28 vertical deflection winding EN inlet face EX outlet face

 ─────────────────────────────────────────────────── ————————————————————————————————————————————————————————————— Inventors William Hen Rivercow Pennsawkengsens Avenir 7235, New Jersey, United States 7235

Claims (1)

[Claims] 1. A picture tube having an electron gun structure for generating a plurality of in-line type electron beams in a neck portion facing a display screen; and a picture tube attached to the neck portion, which deflects the electron beam to display on the display screen. A deflection yoke forming a raster, the deflection yoke generating a vertical and a horizontal deflection magnetic field having a magnetic core and positive and negative on-axis astigmatism, respectively, so that the beam is substantially at all points on the raster. Vertical and horizontal deflection windings, which have a negative peak on the electron gun side, and the same magnitude as the negative peak from the turning point near the entrance face of the yoke. A horizontal magnetic field having a horizontal magnetic field distribution function H _II2 that has a _height and changes toward a positive peak located closer to the outlet surface than the inlet surface of the yoke. -Television display device.