JPH0576738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a deflection device for a color picture tube suitable for use in a single tube video projector.

[Conventional technology]

Conventionally, for example, as a beam index type color picture tube deflection device constituting a single tube video projector, a single electron beam is used to convert red, green, and blue colors, as described in Japanese Patent Laid-Open No. 54-88724. A phosphor surface in which colored phosphor stripes are arranged repeatedly in the horizontal scanning direction is scanned, and index phosphor stripes arranged in the horizontal scanning direction on the inner surface of the phosphor surface are scanned by an electron beam. When the electron beam scans the red color phosphor stripe, it uses the red primary color signal, when it scans the green color phosphor stripe, it uses the green primary color signal, and when the electron beam scans the green color phosphor stripe, it uses the green primary color signal. When scanning the color phosphor stripes, some of the blue primary color signals are density modulated.

In such a deflection device for a color picture tube, the shape of the beam spot is elongated in accordance with the color phosphor stripes, so that relatively high brightness can be obtained.

[Problem that the invention seeks to solve]

The width of this color phosphor stripe in the X-axis direction is determined by the resolution, etc., so in order to faithfully produce red when the electron beam is hitting a red color phosphor stripe, the electron beam must be It is necessary to minimize the width of the vertically elongated beam spot in the X-axis direction (hereinafter referred to as the width).

By the way, a uniform magnetic field is generally known as a deflection magnetic field with little deflection distortion. FIG. 6 shows the effective screen and its beam spot when the horizontal and vertical deflection magnetic fields of the above-mentioned beam index type color picture tube are made into uniform magnetic fields. In FIG. 6, beam spot S1 at the center of the screen, beam spot S2 located at the left and right edges of beam spot S1, and beam spot S3 located at the upper and lower edges of beam spot S1 are respectively The longitudinal direction of each is parallel to the Y-axis direction, and the width in the Y-axis direction (hereinafter referred to as vertical width).
Although a1, a2, and a3 are approximately equal, the beam spot S4 located at the corner of the screen is tilted diagonally with respect to the Y-axis direction, and its vertical width
a4 and horizontal axis b4 are the vertical widths of beam spot S1, respectively.
It was wider than A1 and width B1. For this reason,
At the corner of the screen, the beam spot S4 is tilted with respect to the Y-axis direction as shown in Figures 6 and 7, so this is equivalent to an increase in the width of the color phosphor stripes B, R, and G. , when the beam spot S4 strikes, for example, the color phosphor stripe R, the blue and green color phosphor stripes B
and G, and there was a drawback that blue and green lights were emitted in addition to red, resulting in a decrease in color purity.

In view of this, it is an object of the present invention to propose a device which can obtain a vertically elongated beam spot over the entire screen and can obtain an image with high color purity.

[Means for solving problems]

The deflection device for a color picture tube of the present invention is a saddle in which a horizontal deflection yoke and a vertical deflection yoke are used to obtain a barrel magnetic field on the neck side and a pink tension magnetic field on the aperture side, respectively, in a color picture tube designed to obtain a vertically elongated beam spot. The window width on the opening side of the horizontal deflection coil of the horizontal deflection yoke is made a predetermined times larger than the window width on the neck side, and the window width on the opening side of the vertical deflection coil of the vertical deflection yoke is made larger. The window width is made to be a predetermined times larger than the width of the window on the network side.

[Effect]

According to such a configuration, a good vertically elongated beam spot can be obtained over the entire screen, and a good image with high color purity can be obtained.

〔Example〕

Hereinafter, one embodiment of the color picture tube of the present invention will be described with reference to FIGS. 1 to 5. In FIGS. 1 to 5, parts corresponding to those in FIGS. 6 and 7 are given the same reference numerals, and detailed explanation thereof will be omitted.

Before explaining the deflection device for a color picture tube according to the present invention, the relationship between the deflection magnetic field and the beam spot will be explained.

First, in the horizontal deflection coil, a pincushion magnetic field is effective as a deflection magnetic field in order to make the beam spot S4 at the corner of the screen stand in the Y-axis direction. In this case, as shown in Fig. 2, the width of beam spots S4 and S2 at the corner and the upper edge of the X axis is
Since a2 and a4 are wider than the width a1 of the beam spot S1 at the center of the screen, there is no so-called landing allowance. Also, beam spots S4 and S
The vertical widths b4 and b2 of 2 are the vertical width b1 of beam spot S1.
will be shorter than Also, the part that is effective for focusing the beam spot is the neck side of the deflection yoke.
The so-called spot tilt of the beam spot is more effective on the aperture side. In order to make the beam spot stand in the Y-axis direction at the corner with as little deflection distortion as possible, the deflection magnetic field on the neck side should be a barrel magnetic field, and the deflection magnetic field on the aperture side should be a pink tension magnetic field, as shown in Figure 3. It is desirable that the magnetic field received by the electron beam as a whole is uniform.

Next, in the vertical deflection coil, a pincushion magnetic field is effective as the deflection magnetic field in order to make the beam spot stand up in the Y-axis direction at the corner, similar to the above-mentioned horizontal deflection coil. In this way, when the vertical deflection magnetic field is a pink tension magnetic field, the vertical widths b4 and b3 of the beam spots S4 and S3 at the corner and the upper edge of the Y axis are larger than the vertical width b1 of the beam spot S1 at the center of the screen, as shown in Fig. 4. The widths a4 and a3 of beam spots S4 and S3 become narrower than the width a1 of beam spot S1. In this case, the vertical width b4 of beam spots S4 and S3
If b3 is too long, even if the spot tilt is tilted by just 1 degree in the Y-axis direction due to variations in resolution and deflection yoke assembly, the landing allowance will decrease due to the increase in the width of the beam spot due to this tilt, resulting in mislanding. It becomes more likely to occur.

In this example, as shown in FIGS. 1 and 3, a barrel magnetic field is obtained on the neck side of the horizontal deflection yoke and a vertical deflection yoke, respectively, and a pink tension magnetic field is obtained on the opening side of the horizontal deflection yoke, respectively, so that the magnetic field received by the electron beam as a whole is uniform. Each is configured in a saddle shape so that Also, the strength of the magnetic field of the horizontal deflection coil H of the horizontal deflection yoke is measured at the beam spot S1 at the center of the screen.
The vertical width of the beam spot on the X axis at the position of 90% of the effective screen is 75 to 100 of b1.
%, and the strength of the magnetic field of the vertical deflection coil V is determined by the vertical width b1 of the beam spot S1 at the center of the screen, and the vertical width of the beam spot on the Y axis at a position of 90% of the effective screen is 100 to 135 of b1. %, that is, the window width on the opening side of the horizontal deflection coil H.
W1 is made a predetermined times, for example, 3 to 4 times, the window width W2 on the neck side, and the window width W3 on the opening side of the vertical deflection coil V of the vertical deflection yoke is made a predetermined time compared to the window width W4 on the neck side. For example, increase the amount by 3 to 4.5 times.

Note that the configuration is the same as the conventional one so that a vertically elongated beam spot can be obtained.

According to this configuration, the electron beam emitted from the electron gun is deflected in a predetermined manner by the horizontal and vertical deflection coils H and V forming the horizontal and vertical deflection yokes, respectively. At this time, the horizontal and vertical deflection yokes were each constructed in a saddle shape, as shown in Figure 3, so that a barrel magnetic field was obtained on the neck side and a pink tension magnetic field was obtained on the aperture side, so that the magnetic field received by the electron beam was uniform as a whole. Therefore, the deflection distortion experienced by the electron beam can be made relatively small.

A beam spot formed by an electron beam deflected in this manner is shown in FIG. In this case, the strength of the magnetic field of the horizontal deflection coil H is determined by the vertical width b1 of the beam spot S1 at the center of the screen, and the vertical width b1 of the beam spot on the X axis at a position of 90% of the effective screen.
75 to 100% and the strength of the magnetic field of the vertical deflection coil V to the vertical width of the beam spot S1 at the center of the screen.
The vertical width of the beam spot on the Y axis at the position of 90% of the effective screen with respect to b1 is 100 to 135% of the length of b1, that is, on the opening side of the horizontal deflection coil H of the horizontal deflection yoke. The window width W1 on the opening side of the vertical deflection coil V of the vertical deflection yoke is made 3 to 4 times larger than the window width W2 on the neck side, and the window width W3 on the opening side of the vertical deflection coil V of the vertical deflection yoke is 3 to 4 times larger than the window width W4 on the neck side. 4.5 times, the horizontal width a4 and vertical width b4 of the beam spot S4 at the corner are the horizontal width a1 and vertical width b1 of the beam spot S1 at the center of the screen, respectively, due to the above-mentioned relationship between the deflection magnetic field and the resulting beam spot.
The spot tilt of the beam spot S4 at the corner is made equal to the spot tilt of the beam spot S1 at the center of the screen. Also, the width of the beam spot S2 at the upper edge of the X-axis
a2 is greater than the width a1 of beam spot S1,
The vertical width b2 of this beam spot S2 is made smaller than the vertical width b1 of the beam spot S1, and the horizontal width a3 of the beam spot S3 at the upper edge of the Y axis is made less than the horizontal width a1 of the beam spot S1. The vertical width b3 is made larger than the vertical width b1 of the beam spot S1. For this reason,
A vertically elongated beam spot whose longitudinal direction is parallel to the Y-axis direction can be obtained over the entire screen, and a good image with high color purity can be obtained.

As described above, according to this example, in a color picture tube designed to obtain a vertically elongated beam spot,
The horizontal deflection yoke and the vertical deflection yoke are each configured in a saddle shape that provides a barrel magnetic field on the neck side and a pincushion magnetic field on the aperture side, and the strength of the magnetic field of the horizontal deflection coil H is adjusted vertically to the beam spot S1 at the center of the screen. The vertical width of the beam spot on the X axis at the position of 90% of the effective screen with respect to width b1 is 75 to 100% of b1, and the strength of the magnetic field of the vertical deflection coil V is set to beam spot S at the center of the screen.
1, the vertical width of the beam spot on the Y axis at the position of 90% of the effective screen is 100 to b1
The window width W1 on the opening side of the horizontal deflection coil H of the horizontal deflection yoke is made 3 to 4 times the window width W2 on the neck side so that the length is 135%, and the vertical deflection coil V of the vertical deflection yoke is Window width on the opening side of
Since W3 is set to 3 to 4.5 times the window width W4 on the net side, a good vertical beam spot with the longitudinal direction parallel to the Y-axis direction can be obtained over the entire screen.
There is an advantage that a good image with high color purity can be obtained.

It goes without saying that the present invention is not limited to the above-described embodiments, and can take various other configurations without departing from the gist of the present invention.

〔Effect of the invention〕

According to the deflection device for a color picture tube of the present invention, a good vertically elongated beam spot can be obtained over the entire screen, and there is an advantage that a good screen with high color purity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the main part of the deflection device for a color picture tube according to the present invention, FIG. 2, FIG. 4, and FIG.
The figures are a schematic diagram to explain the diagram in Figure 1, Figure 3 is a diagram to explain the deflection magnetic field in Figure 1, and Figures 6 and 7 are diagrams to explain the beam spot of a conventional color picture tube. FIG. H is horizontal deflection coil, V is vertical deflection coil, S
1, S2, S3, and S4 are beam spots at the center of the screen, the upper edge of the X axis, the upper edge of the Y axis, and the corners, respectively, and R, G, and B are color phosphor stripes of red, green, and blue, respectively.

Claims (1)

[Claims] 1. It has a horizontal deflection yoke and a vertical deflection yoke each formed in a saddle shape so as to obtain a barrel magnetic field on the neck side and a pink tension magnetic field on the opening side, and a window on the opening side of the horizontal deflection coil of the horizontal deflection yoke. The width is made 3 to 4 times the width of the window on the neck side, and the window width on the opening side of the vertical deflection coil of the vertical deflection yoke is made 3 to 4.5 times the width of the window on the neck side, and the shape of the beam spot is adjusted. 1. A deflection device for a color picture tube, characterized in that the deflection device is configured to be vertically elongated.