JPS6290094A - Color image receiving tube - Google Patents

Abstract

PURPOSE:To maintain an excellent convergence dignity even if a color image receiving tube is operated at a high horizontal scan frequency by flowing the 1st vertical deflection current to a coil wound on both side leg parts so as to generate a magnetic flux in the same direction as the vertical magnetic flux of a deflection yoke and flowing the 2nd vertical deflection current to a coil wound on a central leg part so that fluxes generated by each auxiliary coils can be positioned in the direction strengthening each other on an electronic gun array surface. CONSTITUTION:When the vertical deflection current flows in coils 3a-3d on the leg parts at both sides, magnetic fluxes 101 and 102 are emitted from the leg parts, and a pin cushion flux synthesized with the neck side flux of the vertical coil is formed. In the pin cushion flux, a deflection force 11 strongly acting on beams 5g, 5r and 5b more strongly acts on the center beam 5g than side beams 5r and 5b to correct a VCR. Deflection forces 131 and 132 caused by fluxes 121 and 121 generated by the coils 4a and 4b at the central leg part is reverse with respect to both side beams 5r and 5b, whereby an YV error can be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color picture tube, and more particularly to a color picture tube for high-resolution displays that incorporates an in-line electron gun.

[Technical Background of the Invention and Problems Thereof 3 Next, an example of a conventional in-line dot type color picture tube for display will be explained with reference to FIGS. 8 to 12.

That is, a panel (21) on the inner surface of which is formed a phosphor screen (20) in which circular phosphor dots that emit light in three colors (usually red, green, and blue) are arranged regularly.

A shadow mask (23) having a circular electron beam hole (22) opposite to this phosphor screen (20)
, a neck (25) connected to the panel (21) via a funnel (24), a center beam (5g), and both side beams (5r) installed inside the neck (25).
, (5b) and a deflection yoke (27) installed on the outer wall from the funnel (24) to the neck (25). ) and consists of at least

The feature of this in-line type is that the deflection yoke (27) generates a non-uniform magnetic field, so that the color picture tube body and the deflection yoke (
Only in combination with 27), 3 beams (3
g) It is possible to realize so-called self-convergence, which makes the rasters of (3r) and (3b) substantially coincident.

Currently, the mainstream structure of color picture tubes for in-line displays is the above-mentioned self-convergence type, which also corrects raster distortion at the top and bottom of the screen.

Typical deflection magnetic field distributions of this self-convergence type deflection yoke are the horizontal deflection magnetic field distribution (27) shown in FIG. 9(a) and the vertical deflection magnetic field distribution (27) shown in FIG. 9(b).
28). However, (0) is the neck side, (Z)
is the tube axis.

However, with a deflection yoke having such a deflection magnetic field distribution, it is possible to substantially match the side beams, that is, the red (R) and blue (B) rasters on the screen; It is difficult to match the center beam, that is, the green (G) raster, and as shown in Figure 10, the green (G) raster is more vertical than the red (R) and blue (8) rasters. Errors at the vertical axis end (VCR) at the axis end and horizontal axis end, respectively.
and horizontal axis end error (HCR). This is generally called a coma error. Among these errors, the vertical axis end error (VCR) is particularly large, causing an error of about 1 to 2 mm even in a 14-inch tube.

In order to correct the above-mentioned coma error, a magnetic element generally called a field controller is placed in the leakage magnetic field of the deflection yoke on the phosphor screen side of the electron gun.

An example of this field controller is as shown in Fig. 11.
), the shank +- (30□), (3
02) and enhancers (31□) and (32□) provided on both sides of the center beam passage hole (32G). By shaping the leakage magnetic field using these magnetic elements, the amount of deflection of both side beams and the center beam can be corrected, and the rasters on the screen can be made to match.

By the way, one of the problems with using the above field controller is unbalanced convergence. Figure 12 is the most obvious example, red (
This is a phenomenon in which the lighter is shifted to the right, shown by the solid line, obtained with the green (G) center beam, rather than the raster shown by the broken line, obtained with both the R) and blue (B) side beams. This is related to horizontal scanning from the left to the right of the screen, and is thought to be caused by the hysteresis characteristics of the magnetic element.

This phenomenon tends to increase as the horizontal scanning frequency (f n ) increases. In other words, if the fi+ is about 15.75kHz, which is currently used in home television equipment, the amount of rubbing is about O.Lmm, which is usually not a problem. The fl of color picture tubes has increased to about 64 kHz, and color picture tubes are also required to provide clear image quality at this frequency. Therefore, it is difficult to maintain good convergence characteristics in a field controller that uses magnetic elements as shown in FIG. 11.

Therefore, in a color picture tube operated at a high horizontal scanning frequency of about 64 kHz, it is desirable to correct the coma error using the deflection yoke itself, without using a field controller consisting of a magnetic element.

Such a deflection yoke is called a coma-free type.

FIG. 13 shows an example of a deflection magnetic field of a self-convergence and coma-free deflection yoke. That is.

Figure 13(a) shows the horizontal deflection magnetic field (33), and the neck side of this horizontal deflection magnetic field (33) becomes a stronger barrel magnetic field than the one shown by the broken line in Figure 7(a). ing. Such a horizontal deflection magnetic field (33) can be realized by increasing the isometric winding angle on the neck side. Moreover, although FIG. 13(b) shows the vertical deflection magnetic field (34),
On the neck side of this vertical deflection magnetic field, a much stronger bottle cushion magnetic field is required compared to the one shown by the broken line in Figure 11(b). It is difficult to achieve this alone.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a color picture tube that can maintain good convergence quality even when operated at a high horizontal scanning frequency.

[Summary of the invention]

That is, the present invention provides a panel having a phosphor screen formed on its inner surface, a shadow mask placed opposite to the phosphor screen, a neck connected to the panel via a funnel, and a shadow mask mounted in the neck. In a color picture tube equipped with an in-line electron gun and a deflection yoke provided on the outer wall from the funnel to the neck, the E-type picture tube has central and opposite legs on the neck side of the deflection yoke.
A pair of auxiliary coils consisting of a letter-shaped magnetic core and a winding wound around each leg are arranged in a plane substantially perpendicular to the tube axis, and each leg is opposed to the in-line electron gun. The first vertical deflection current is passed through the windings arranged symmetrically across the array plane and wound around the legs on both sides to generate a magnetic field in the same direction as the vertical magnetic field of the deflection yoke. A second vertical deflection current is passed through the windings wound around the legs of the electron beam so that the magnetic fields generated by the respective auxiliary coils are strengthened in the electron gun array plane. This is a color picture tube with special features.

[Embodiments of the invention]

Next, one embodiment of the color picture tube of the present invention will be described with reference to FIGS. 1 to 7. In the figure, the same reference numerals as in the conventional example indicate the same parts.

In other words, a color picture tube has three colors (usually red, green, and blue) on its inner surface.
A panel (21) on which a phosphor screen (20) is formed by regularly arranging circular phosphor dots that emit light.
and a shadow mask (2) having a circular electron beam hole (22) opposite to this phosphor screen (20).
3), a neck (25) connected to the panel (21) via a funnel (24), a center beam (5g) installed in the neck (25), and both side beams (5r).
), (5b) and an in-line electron gun (26) arranged along the X-axis to focus and emit
4) to the neck (25), and the neck (27) of the deflection yoke (27).
5) E-shaped core (1), (2) with central and both side legs respectively on the sides and a winding wound around each leg (
A pair of auxiliary coils (6a) consisting of 3a), (3b), (3c), (3d) and (4a) (4b)
) and (6b) are in a plane substantially perpendicular to the tube axis, and the in-line electron gun (26)
are arranged symmetrically across the array plane, and these windings
As shown in the figure, it is connected in series with the vertical deflection coils (7□) (7□). In FIG. 3, (8) is an adjustment resistance for the coma error (VCR) at the vertical axis end, and (9) is an adjustment resistance for the error (Yv) in which the raster size drawn by both side beams is different at the vertical axis end.

These windings (3a), (3b), (3c),
(3d) and winding (4a).

(4b) works differently.

First, as shown in Figure 4, windings (3a) and (3b) on both sides.
, (3c).

The principle of VCR correction based on (3d) will be explained. That is, FIG. 4 is a view seen from the phosphor screen side, and shows the case where the light is deflected to the upper side of the screen. Windings on both legs (3a),
When a vertical deflection current flows through (3b), (3c), and (3d), magnetic flux (10□) (10□) is emitted from the legs, and a bottle cushion magnetic field is formed by combining with the neck side magnetic field of the vertical coil. Ru. For this bottle cushion magnetic field.

The horizontal magnetic field Hx for vertically deflecting the beams (5g), (5r), and (5b) is strongest near the central axis (0) as shown in FIG. Therefore, the beam (5
g) , (5r) , (5b) deflection force (
11) acts more strongly on the center beam (5g) than on the side beams (5r) and (5b), and the VCR is corrected. That is, substantially the entire vertical magnetic field shape is the 13th
It becomes equal to the vertical magnetic field distribution curve (34) in Figure (b).

Next, the action of the windings (4a) and (4b) of the central leg will be explained with reference to FIG. That is, although the color picture tube and the deflection yoke each have assembly errors, both sight beams (5r) due to assembly errors in the horizontal axis direction.
There is a pattern shown in FIG. 7 in the convergence error between (5b). This includes both side beams (5r) and (5r)
b) Errors with different raster sizes are represented by errors on the horizontal axis (XH) and errors on the vertical axis (Yv).

Normally, this type of error can be corrected by tilting the deflection yoke in the horizontal axis direction with respect to the color picture tube when attaching the deflection yoke to the color picture tube, but if both Yv and XH become zero at the same time. However, some errors remain, which is a problem with high-resolution tubes.

Therefore, as shown in Figure 6, the central leg winding (4a)
, (46) generates a magnetic field (12,) (12
The deflection force (13,) (1,3,) due to K) is in the opposite direction to both side beams (5r) and (5b), thereby making it possible to correct the Yv error. Therefore, first, xH is corrected by installing the deflection yoke at an angle with respect to the color picture tube, and then the winding (4a)
, (4b), the convergence error of the pattern shown in FIG. 7 can be almost completely eliminated.

Further, Yv mentioned here is a component generated due to assembly error, and the design center value is zero. Therefore, the number of windings in the central leg (4a) and (4b) is the same as the winding (3a) in both legs that corrects the VCR itself.

It is sufficient if it is compared with the number of windings in (3b), (3c), and (3d). Note that the windings (3a) on both sides, (
3b), (3c), (3d) and the central windings (4a), (4b) are considered to be independent of each other.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a high-resolution color picture tube that has good convergence characteristics and is particularly suitable for operation at high horizontal scanning frequencies. In addition, in the present invention, the magnetic field distribution of the deflection yoke is of a coma-free type as shown in FIGS. That is, it becomes possible to obtain focus characteristics.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a color picture tube of the present invention, and FIG.
The figure is an explanatory diagram showing the relationship between the auxiliary coil in Figure 1 and the beam, Figure 3 is a connection diagram of each winding and the vertical deflection coil in Figure 2,
4 and 5 are explanatory diagrams showing the principle of magnetic flux and beam movement between the legs on both sides of the auxiliary coil, FIG. 4 is an explanatory diagram showing the movement of the auxiliary coil and the beam, and FIG. An explanatory diagram showing the strength distribution of the horizontal magnetic field for vertically deflecting the beam in the case of a bottle cushion magnetic field, Figure 6 is Yv
Figure 7 is an explanatory diagram showing the convergence error pattern due to assembly error. Figure 8 is a partially cutaway side view of a typical color picture tube. Figure 9 is the magnetic field of a self-convergence type deflection yoke. 9(a) is a curve diagram showing the magnetic field distribution of the horizontal deflection coil, FIG. 9(b) is a curve diagram showing the magnetic field distribution of the vertical deflection coil, and FIG. 10 is a curve diagram showing the magnetic field distribution of the vertical deflection coil. An explanatory diagram showing the coma error of a self-convergence type deflection yoke, Fig. 11 is an explanatory diagram showing an example of a field controller, Fig. 12 is an explanatory diagram showing the convergence error of the side beam and center beam that occurs on both sides of the screen, and Fig. 13 13(a) is a curve diagram showing the horizontal deflection magnetic field distribution, and FIG. 13(b) is the vertical deflection magnetic field distribution. It is a curve diagram.

Claims (1)

[Claims] A panel having a phosphor screen formed on its inner surface, a shadow mask placed opposite to the phosphor screen, a neck connected to the panel via a funnel, and an in-line electron gun installed in the neck. and a deflection yoke provided on an outer wall extending from the funnel to the neck, an E-shaped magnetic core having central and opposite leg portions on the neck side of the deflection yoke, and each leg. A pair of auxiliary coils each consisting of a winding wound around the tube are arranged symmetrically across the arrangement plane of the in-line electron gun, with the legs facing each other in a plane substantially perpendicular to the tube axis. A first vertical deflection current is passed through the windings wound around the legs on both sides so as to generate a magnetic field in the same direction as the vertical magnetic field of the deflection yoke. A second vertical deflection current is passed through the windings so as to strengthen the magnetic fields generated by the respective auxiliary coils within the electron gun array plane. A color picture tube featuring