KR0177117B1 - Deflection yoke of in-line type color cathode ray tube - Google Patents

Abstract

The present invention discloses an improved deflection yoke capable of achieving even convergence across the full screen in an inline electron gun system of a color CRT.

The conventional self-convergence electron gun system uses a convergence preservation method such as adjusting the winding distribution of the deflection yoke by using a magnetic component for correction and applying a compensation signal, resulting in an increase in manufacturing cost. There was an unstable problem.

In the present invention, a good self-convergence is achieved over the full screen by using the coupling of the error and the correlation of the distance between the deflection yoke and the screen.

Description

Deflection yoke of inline colored cathode ray tube

1 is a cross-sectional view of a cathode ray tube having an inline electron gun.

2 is a conceptual diagram illustrating isotropic astigmatism.

3 is a conceptual diagram illustrating anisotropic astigmatism.

* Explanation of symbols for main parts of the drawings

1: electron gun 2: screen

3: shadow mask 5: deflection yoke

The present invention relates to an in-line type cathode ray tube, and more particularly to a deflection yoke.

In a general self convergence inline electron gun system, a magnetic component for correcting an electron beam propagation trajectory is applied to the three electron beams at the periphery of the screen to achieve stable convergence and improved raster distortion. In the yoke, a compensation signal is applied, and the winding distribution of the deflection yoke is adjusted to compensate for this. However, these correction methods are causing an increase in manufacturing cost, such as requiring a separate component.

In addition, although convergence can be stably achieved at the center of the screen by such various correction means, it is common to show an unstable convergence state in the periphery of the screen, as shown in FIGS. 2 and 3. Convergence correction can reduce the picture quality of the entire screen.

An object of the present invention is to achieve good self-convergence over the entire screen by using the coupling of the error and the correlation between the deflection yoke and the screen in order to improve the convergence error on the nominal axis.

In order to achieve this object, the deflection yoke of the present invention includes the effective distance of the basic (0th order) magnetic field distribution function Ho (Z), the distance from the deflection center to the screen D, and the electron gun array spacing at the deflection plane d. When the isotropic astigmatism coefficients of the horizontal and vertical deflection coils are A4 and B5, and the anisotropic astigmatism coefficients of the horizontal and vertical deflection coils are A6, B6 and J are 2 / D-1 / le, respectively, leD / 2, J0, A4 = B5 = 0, A40 at the horizontal end, B50 at the vertical end, and (A6 + B6) 0 at the corners of the raster.

In another type of deflection yoke of the present invention, the effective distance of the zeroth order magnetic field distribution function Ho (Z) is le, the distance from the deflection center to the screen D, the electron gun array spacing on the deflection plane d, horizontal and vertical deflection coils. The isotropic astigmatism coefficients of A4 and B5 are respectively, and the anisotropic astigmatism coefficients of the horizontal and vertical deflection coils are A6 and B6, respectively, and J = 2 / D-1 / le. It is characterized by providing the conditions of A4 = B5 = 0 and on-axis trap A6 + B6 = 0 at 0, horizontal and vertical axis ends.

In addition, the deflection yoke of the present invention is the effective distance of the zero-order magnetic field distribution function Ho (Z), the distance from the deflection center to the screen D, the electron gun array spacing in the deflection plane d, the isotropicity of the horizontal and vertical deflection coils When the astigmatism coefficients are A4 and B5, respectively, and the anisotropic astigmatism coefficients of the horizontal and vertical deflection coils are A6 and B6, and J is 2 / D-1 / le, respectively, J0, L / le3, and A40 at the horizontal end. It is characterized by providing a condition of B50 at the vertical end and (A6 + B6) 0 at the raster corner.

Such specific features and advantages of the present invention will become more apparent from the following description of the preferred embodiments with reference to the accompanying drawings.

The convergence error (Δx, Δy) due to the astigmatism of the two outer beams on the screen is given by the following third-order aberration theory.

[Equation 1]

[Equation 2]

Here, Xs and Ys are Gaussian points of the center beam, and X's is the tilt of the beam when it is not deflected. A4 is a horizontal deflection coil, B5 is an isotropic astigmatism coefficient of a vertical deflection coil, and A6 and B6 are respective anisotropic astigmatism coefficients.

From this equation, the inventors found that the fundamental (0th order) magnetic field distribution function Ho (z), which affects the 3rd order spherical aberration coefficient, is mainly in the geometry of the deflection yoke, and the 3rd order astigmatism coefficient is From the fact that it is determined by the winding distribution and the fact that Ho (z) due to horizontal and vertical deflection coils are equivalent approximations in most deflection devices, from equations 1 and 2 of the isotropic and anisotropic astigmatism coefficients It is found that the same relationship as in Equation 3 is achieved.

[Equation 3]

Then, the effective length (le) of the common Ho (z) function by the horizontal and vertical deflection coils related to the actual deflection yoke length is appropriately defined, and the equation is obtained by using the deflection center and the distance D to the screen. Got 4.

[Equation 4]

Equations 3 and 4 obtained in this way are generally inline type cathode ray tubes having deflection yokes and tube lengths, whereby stable deflection of the outer beam on the axis is achieved by setting A4 = B5 = 0 by the winding distribution of suitable deflection coils. At the corners of the screen, there is still a convergence error. That is, it can be seen that J is a constant as (A6 + B5) + A4-B5 = J = 2 / D-1 / le.

Based on these results, the present invention minimizes the convergence error of the vertical horizontal and corner portions between the two outer beams at any part around the raster, and the horizontal and vertical deflection coils are independent of the winding distribution, and the deflection yoke and the tube We found the following equation, which represents the sum of convergence errors due to astigmatism, which can be negative or positive by other combinations of ubes.

[Equation 5a]

[Equation 5b]

[Formula 5c]

By design, a unique trap shape exists even after the winding distribution of the vertical horizontal coil along the length of the deflection yoke is determined for stable convergence on the virtual axis. Based on this, the inline system is divided into the following three embodiments (a) (b) (c).

(a) Short deflection yoke type of short tube

In this case, leD / 2, and the constant J is positive, and if A4 and B5 on the axis are zero, the intrinsic trap (A6 + B6) is positive ((A6 + B6) 0). This type of system uses a deflection yoke that provides A40 at the horizontal end, B50 at the vertical end, and (A6 + B6) 0 at the corners of the raster. Then, one of the convergence errors in the virtual axis by design disappears.

(b) Ideal deflection yoke and tube length

In this case, le = D / 2, the constant J = 0, and when A4 and B5 are 0, the on-axis trap A6 + B6 = 0. In this case, after making A4 = B5 = 0 based on the distance L from the deflection coil inlet to the screen, A6 + B6 = 0 is possible. In order to increase the above conditions and L / le, D = L × le / 2, but J = 0.2 / le0.

(c) Short deflection yoke long tubular

In this case, leD / 2, J0, (A6 + B6) 0, the requirement for the neck combination is L / le3, and the negative value of J induces a negative trap at the corner when the axis is in the normal range. .

The flat yoke produces a negative trap of A40 at the horizontal end, B50 at the vertical end and (A6 + B6) 0 at the raster corner. Therefore, one convergence error is eliminated by design.

1 is a cross-sectional view of a cathode ray tube having an inline electron gun used in the present invention.

In the figure, 1 is an electron gun, 2 is a screen, 3 is a shadow mask, 4 is a glass evelope, 5 is a deflection yoke, 6 is a purity control magnet (PCM), and 7 is a color purity adjusting device (CPAD). And R, G and B are red (R), green (G) and blue (B) beams.

In the in-line cathode ray tube, the arrangement of the electron guns in the screen shows that, in the BGR order, each of the inclinations of the beam characteristic determinants, that is, Xs'B = d / D and Xs'R = -d / D. Here, d is the distance between the arrays of electron guns on the deflection plane, and D is the distance from the deflection plane to the screen. Convergence due to astigmatism independent of the winding distribution of the horizontal and vertical deflection coils, subject to the conditions in a), b) and c), which can be negative or positive by a combination of deflection yoke and tubing. By minimizing the distance between the two beams at the periphery of the screen using the above six equations representing the sum of the errors, good self-convergence is possible over the entire raster. The deflection yoke provides a balance between the slight convergence error on the axis and the convergence error at the corners, depending on the sign shape of the trap difference (A6 + B6) remaining after the winding second of the coil has been determined to obtain good on-axis convergence. It is used according to the conditions a), b) and c).

The self-converging cathode ray tube when A4 = B5 = 0 and leD / 2, (A6 + B6) 0 has some over-convergence (A40) at the horizontal end and some under-convergence (B50) at the vertical end. At the corner portion, the deflection yoke is adjusted so as to have a positive trap difference [(A6 + B6) 0].

After convergence is achieved at the four corners of the screen, adjustment of the winding distribution has no effect on achieving more convergence. This is caused by the interaction between the shaft end and the convergence error occurring at the corners of the raster and is defined as the sum of the same amount as the amount of the trimmer, so the present invention is independent of the winding distribution of the horizontal and vertical coils. However, in the case of a deflection yoke tube combination, it can be assumed to be a negative or positive value. If the amount of trimmer is constant, the trimmer can be removed from an inline cathode ray tube with a 110 ° deflection angle using a shorter vertical deflection coil and core than a horizontal coil. By balancing the convergence error of the nominal axis and the nominal corner based on the trap shape remaining after the winding distribution is established, it does not eliminate the misconvergence in all parts of the screen, but minimizes the longest distance between the outer beams around the raster. And virtually stable convergence is achieved across the screen.

Claims (3)

The effective distance of the basic magnetic field distribution function Ho (Z) is le, the distance from the deflection center to the screen is D, the spacing of electron guns at the deflection plane is d, and the isotropic astigmatism coefficients of the horizontal and vertical deflection coils are A4 and B5, When the anisotropic astigmatism coefficients of horizontal and vertical deflection coils are A6 and B6 and J is 2 / D-1 / le, respectively, leD / 2, J0, A4 = B5 = 0, A40 at the horizontal axis and B0 at the vertical axis, respectively. And a deflection yoke of an inline type color cathode ray tube, characterized by satisfying the condition of (A6 + B6) 0 at the corner of the raster. The effective distance of the basic magnetic field distribution function Ho (Z) is le, the distance from the deflection center to the screen is D, the spacing of electron guns at the deflection plane is d, and the isotropic astigmatism coefficients of the horizontal and vertical deflection coils are A4 and B5, When the anisotropic astigmatism coefficients of the horizontal and vertical deflection coils are A6 and B6 and J is 2 / D-1 / le, respectively, le = D / 2, J = 0 and A4 = B5 = 0 at the horizontal and vertical shaft ends. A deflection yoke of an inline colored cathode ray tube, characterized by satisfying a condition of a trap A6 + B6 = 0. The effective distance of the basic magnetic field distribution function Ho (Z) is le, the distance from the deflection center to the screen is D, the spacing of electron guns at the deflection plane is d, and the isotropic astigmatism coefficients of the horizontal and vertical deflection coils are A4 and B5, When the anisotropic astigmatism coefficients of the horizontal and vertical deflection coils are A6 and B6, J is 2 / D-1 / le, respectively, J0, L / le3, A40 at the horizontal end, B50 at the vertical end, and raster A deflection yoke of an inline type color cathode ray tube, characterized by satisfying a condition of (A6 + B6) 0 at a corner.