JPH04269435A - Color television picture tube - Google Patents

Abstract

PURPOSE:To improve focusing characteristics by profitably using the advantage of a self-convergence method without degrading the quality of an image. CONSTITUTION:A color television picture tube is composed of a fluoroscent plane 20 consisting of 3-color phosphor-dots 26B, 26G, 26R which are arranged to form a delta and arranged in a row vertically, an electron gun 22 for emitting 3 electron beams which are arranged in a row and pass the same vertical plane as hat of the 3-color phosphor dots, a shadow mask 21 in which a large number of circular electron beam passing holes 27, are formed, and a deflecting apparatus having a horizontally deflecting coil which generates a horizontally deflecting magnetic field mainly in barrel-type magnetic flux density distribution to deflect horizontally the above 3 electron beams and a vertically deflecting coil which generates a vertically deflecting magnetic field mainly in pin-cushion-type magnetic flux density distribution to deflect those electron beams vertically.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and more particularly to a color picture tube with good focus characteristics useful for high-definition displays such as character displays and graphic displays.

0002

2. Description of the Related Art Generally, a color picture tube has a glass envelope consisting of a panel 1 and a funnel 2 integrally joined to the panel 1, as shown in FIG. A phosphor screen 3 made of three-color phosphor layers that emit light in , green, and red is formed, and a shadow massmer 4 having a large number of electron beam passage holes formed inside the phosphor screen 3 is arranged opposite to this phosphor screen 3. ing. Also, the neck 5 of funnel 2
An electron gun 7 that emits three electron beams 6B, 6G, and 6R is arranged inside. The three electron beams 6B, 6G, and 6R emitted from the electron gun 7 are deflected into a horizontal deflection magnetic field generated by a horizontal deflection coil of a deflection device 8 mounted on the outside of the funnel 2 and a vertical deflection generated by a vertical deflection coil. The phosphor screen 3 is deflected by a magnetic field to horizontally and vertically scan the phosphor screen 3, thereby displaying a color image on the phosphor screen 3.

By the way, regarding color picture tubes that perform high-definition displays such as character displays or graphic displays, various performance improvements have been made to the above-mentioned general color picture tubes.

One of the main improvements in performance is focus characteristics. This focus characteristic is determined by the size and shape of the beam spot on the phosphor screen, and in order to improve the focus characteristic, it is necessary to make the beam spot as small as possible and as close to a perfect circle as possible.

However, since a color picture tube is usually configured in a landscape type with a horizontally long screen, the deflection distance of the electron beam that scans the horizontally long screen (from the time it is emitted from the electron gun to the phosphor screen) is ) is longer in the horizontal direction than in the vertical direction, and this difference in deflection distance affects the focus characteristics.

Another major improvement in performance is 3.
This is a convergence characteristic that focuses the electron beam on a single point on the phosphor screen.

Regarding this convergence characteristic, currently, the electron gun is an in-line type electron gun that emits three electron beams arranged in a row at a predetermined interval, consisting of a center beam and a pair of side beams passing on the same horizontal plane, and a deflection device. A self-convergence type in-line collar that self-concentrates the three electron beams arranged in a row emitted from the in-line electron gun using the non-uniform magnetic field that appropriately distorts the horizontal and vertical deflection magnetic fields generated by the in-line electron gun. Picture tubes have become the mainstream color picture tube.

This concentration by a non-uniform magnetic field is a method that utilizes the aberration (astigmatism) that occurs when three electron beams pass through the distorted magnetic field lens at a certain interval, and the three electron beams arranged in a row are self-concentrated. It is possible to concentrate, but
At the same time, astigmatism is generated in each electron beam itself.

That is, for the three electron beams arranged in a row passing on the same horizontal plane, a deflection device is used which generates a horizontal deflection magnetic field mainly having a pincushion-shaped magnetic flux density distribution and a vertical deflection magnetic field mainly having a barrel-shaped magnetic flux density distribution. used. In a horizontal deflection magnetic field with a mainly pincushion-shaped magnetic flux density distribution, the magnetic flux density distribution becomes 9 as shown in FIG. 11a, 11
When it receives a deflection force indicated by b , its cross-sectional shape is distorted into an ellipse with the long axis in the horizontal direction (X-axis direction) as indicated by 10 b . In addition, in a vertical deflection magnetic field mainly having a barrel-shaped magnetic flux density distribution, the magnetic flux density distribution becomes 12 as shown in (b), and the cross-sectional shape of the electron beam emitted from the electron gun is a perfect circle 10
However, the electron beam is subjected to deflection forces shown by arrows 12a and 12b, distorting its cross-sectional shape into an ellipse with the long axis in the horizontal direction as shown by 10c, and deteriorating the focusing characteristics.

[0010] Moreover, the degree of deterioration of the focus characteristic is more likely to be affected as the deflection distance becomes longer. Therefore, the landscape type color picture tube is significantly affected by horizontal deflection, and the greater the deflection angle, the greater the effect. As a result, high-definition TVs (High D), which are even wider than current color picture tubes
Color picture tubes for finition TVs will be more affected.

In addition, in a full square tube where the curved surface of the panel is made more flat, the electron beam will be incident on the phosphor screen more obliquely, and the beam spot on the phosphor screen will form an ellipse with its long axis in the horizontal direction. This will further encourage In particular, the influence on the focus characteristics due to the flattening of the panel acts to offset in the vertical direction and to enhance it in the horizontal direction, resulting in a significant deterioration of the focus characteristics.

Conventionally, there are the following two methods for improving this deterioration of focus characteristics.

One of the methods is to form the cross-sectional shape of the electron beam emitted from the electron gun into a vertically elongated ellipse in advance. However, in order to make the beam spot uniform over the entire screen using this method, it is necessary to apply a dynamic voltage (usually It is necessary to apply a parabolic waveform), which requires a large-scale drive circuit for the color picture tube. Furthermore, with this method, the correction is limited to the halo portion at the periphery of the beam spot, and does not extend to the core portion at the center. Furthermore, there are other problems such as difficulty in controlling the correction.

Another method is to improve convergence over the entire screen. However, this method uses a convergence correction coil and a correction circuit in addition to the normal deflection device, which increases the cost and is not a good method.

[0015]

[Problems to be Solved by the Invention] As mentioned above, focus characteristics and convergence characteristics are the main improvements in the performance of color picture tubes. In a tube, the deflection magnetic field is a nonuniform magnetic field with mainly a pincushion-shaped magnetic flux density distribution in the horizontal direction and a mainly barrel-shaped magnetic flux density distribution in the vertical direction, so the cross-sectional shape of the electron beam is shaped like an ellipse with the long axis in the horizontal direction. distorts and deteriorates focus characteristics. The degree of deterioration in focus characteristics is significantly affected by horizontal deflection in landscape-type color picture tubes, and the larger the deflection angle, the greater the effect. Pipes will be more affected. Also,
In a full square tube where the curved surface of the panel is more flat, the electron beam will be incident on the phosphor screen more obliquely, which will further promote the ovalization of the beam spot on the phosphor screen with the long axis in the horizontal direction. , the focus characteristics are significantly deteriorated.

Conventionally, as means for improving this deterioration of focus characteristics, there are a method in which the cross-sectional shape of the electron beam emitted from an electron gun is made into a vertically elongated ellipse, and a method in which convergence is improved over the entire screen. However, the method of forming the cross-sectional shape of the electron beam emitted from the electron gun into a vertically elongated ellipse requires a large-scale drive circuit for the color picture tube, and correction is limited to the halo area around the beam spot. There are problems in that the correction does not reach the core portion in the center and it is difficult to control the correction. Also,
The method of achieving good convergence over the entire screen uses a convergence correction coil and a correction circuit in addition to a normal deflection device, which poses problems such as increased costs.

The present invention was made in view of the above-mentioned problems, and aims to construct a color picture tube with good focus characteristics by adopting the self-convergence method, which is the mainstream of current color picture tubes. shall be.

[Configuration of the invention]

[0019]

[Means for solving the problem] In a color picture tube,
The phosphor screen is made up of multiple sets of three-color phosphor dots, one set of three-color phosphor dots in a Δ arrangement, and the three-color phosphor dots are arranged in a line in the vertical direction,
The electron gun is an electron gun that emits three electron beams arranged in a row that pass on the same vertical plane, and a shadow mask is arranged to face the fluorescent screen, and the three electron beams emitted from the electron gun are emitted from the three-color fluorescent screen. A shadow mask is formed with a large number of circular electron beam passage holes for sorting out the body dots, and a deflection device is used to horizontally deflect the three electron beams emitted from the electron gun, mainly with a barrel-shaped magnetic flux density distribution. The deflection device has a horizontal deflection coil that generates a magnetic field and a vertical deflection coil that generates a vertical deflection magnetic field mainly having a pincushion-shaped magnetic flux density distribution that deflects the three electron beams emitted from the electron gun in the vertical direction.

[0020]

[Operation] As mentioned above, if the horizontal deflection magnetic field is mainly a magnetic field with a barrel-shaped magnetic flux density distribution, and the vertical deflection magnetic field is mainly a magnetic field with a pincushion-shaped magnetic flux density distribution, which has a short deflection distance and relatively little deterioration of focus characteristics. The horizontal deflection magnetic field mainly having a barrel-shaped magnetic flux density distribution can reduce the ellipticalization of the beam spot with the long axis in the horizontal direction, compared to the conventional horizontal deflection magnetic field mainly having a pincushion-shaped magnetic flux density distribution. Therefore, by combining this with a phosphor screen in which three-color phosphor dots arranged in a Δ arrangement are arranged vertically in a row, and an electron gun that emits three electron beams arranged in a row that pass on the same vertical plane, a self-convergence method can be realized. Taking advantage of these characteristics, a color picture tube with good focus characteristics can be constructed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments with reference to the drawings.

FIG. 1 shows a color picture tube which is one embodiment of the present invention. This color picture tube has an approximately rectangular panel 1.
and an envelope consisting of a funnel-shaped funnel 2 integrally joined to this panel 1, a fluorescent screen 20 is formed on the inner surface of the panel 1, and a rectangular A shadow mask 21 is arranged. Further, an electron gun 22 is arranged within the neck 5 of the funnel 2. Furthermore, a deflection device (not shown) is attached to the outside of the boundary between the cone portion 23 of the funnel 2 and the neck 5.

As shown in FIG. 2, the phosphor screen 20 has a Δ
Dot-shaped three-color phosphor layer 2 that emits blue, green, and red light in an arrangement
It consists of a mosaic arrangement of many sets of three-color phosphor layers 26B, 26G, 26R, each set being 6B, 26G, 26R. In the phosphor screen of a conventional color picture tube that has dot-shaped three-color phosphor layers arranged in a Δ arrangement, the three-color phosphor layers are arranged in a row on a line that intersects at an angle of 60° with the horizontal axis as one alignment axis. However, the phosphor screen 20 of the color picture tube in this example has three color phosphor layers 26B and 26G.
, 26R are arranged in a line on a line that intersects at an angle of 60° with the vertical direction (Y-axis direction) as one arrangement axis.

These three color phosphor layers 26B, 26G, 2
As shown in FIG. 3, the shadow mask 21 for the 6R arrangement includes a set of three-color phosphor layers 26B,
A large number of electron beam passing holes 27 corresponding to 26G and 26R are formed, and the electron beam passing holes 27 are arranged in a line on a line that intersects at an angle of 30° with the vertical axis direction as one alignment axis.

Further, the electron gun 22 is connected to three of the fluorescent screens 20.
Corresponding to the arrangement of the color phosphor layers 26B, 26G, 26R and the arrangement of the electron beam passing holes 27 of the shadow mask 21, three electron beams arranged in a row consisting of a center beam and a pair of side beams passing on the same vertical plane are arranged. It is an in-line type electron gun that emits electrons. This electron gun 2
No. 2 has the same structure as the in-line electron gun of a conventional color picture tube, but differs in the arrangement direction of the emitted three electron beams. That is, the electron gun 22 in this example is an in-line type electron gun arranged in a vertical direction, in which unit electron guns 28 that emit each electron beam are arranged in a vertical direction.

Further, in the deflection device, the horizontal deflection coil generates a horizontal deflection magnetic field mainly having a barrel-shaped magnetic flux density distribution,
The vertical deflection coil mainly generates a vertical deflection magnetic field with a pincushion-shaped magnetic flux density distribution. This deflection device is different from the conventional self-convergence type in-line color picture tube deflection device in which the horizontal deflection magnetic field is mainly a pincushion-shaped magnetic flux density distribution, and the vertical deflection magnetic field is mainly a barrel-shaped magnetic flux density distribution. The difference is that the shape of the deflection magnetic field is reversed.

By the way, when the color picture tube is configured as described above, the deterioration of focus characteristics, which is a problem with conventional color picture tubes, can be easily improved by making use of the characteristics of the self-convergence system.

That is, by making the horizontal deflection magnetic field generated by the deflection device 24 barrel-shaped, a beam spot having a long axis in the horizontal direction, which is generated because the deflection distance in the horizontal direction is longer than the deflection distance in the vertical direction, can be reduced. Ovalization can be reduced compared to the conventional pincushion type horizontal deflection magnetic field (see FIGS. 5(a) and 5(b)), and good focusing characteristics can be obtained. In other words, the electron gun 22 is an in-line electron gun that emits three electron beams arranged in a row passing on a vertical plane, and the horizontal deflection, which tends to deteriorate focus characteristics due to a long deflection distance, is shaped like a barrel, and the deflection distance is By adopting a self-convergence system that combines a deflection device 24 that generates a non-uniform magnetic field with a pincushion-shaped vertical deflection that has a relatively short length and has little effect on focus characteristics, the characteristics of the self-convergence system can be utilized. This reduces the ellipticalization of the beam spot due to horizontal deflection, and reduces the difference between the ellipticalization of the beam spot due to horizontal deflection and the ellipticalization of the beam spot due to vertical deflection, resulting in good focus characteristics over the entire screen. It can be used as a color picture tube.

In this case, if the phosphor screen is composed of three-color phosphor layers in the form of long and narrow stripes in a direction perpendicular to the direction in which the three electron beams are arranged, as in the conventional in-line color picture tube, the stripe-like phosphor Since the body layer extends in the horizontal direction, it interferes with the horizontal scanning line and causes an extreme moiré phenomenon. ,26G ,26R
and its three-color phosphor layers 26B and 26G
, 26R are arranged in a line in the vertical axis direction and have no alignment axis in the horizontal direction, thereby making it possible to prevent moiré phenomena caused by interference between the phosphor layer and the horizontal scanning line.

[0030]

[Effect of the invention] Three color phosphor dots arranged in Δ on the phosphor screen
The phosphor screen is made up of multiple sets of three-color phosphor dots, and the three-color phosphor dots are arranged in a line in the vertical direction, and the electron gun is arranged in a line that passes through the same vertical plane.
The electron gun emits an electron beam, the shadow mask is a shadow mask with a large number of circular electron beam passing holes, and the deflection device is mainly a barrel-shaped magnetic flux that horizontally deflects the three electron beams emitted from the electron gun. A deflection device having a horizontal deflection coil that generates a horizontal deflection magnetic field with a density distribution and a vertical deflection coil that generates a vertical deflection magnetic field with a mainly pincushion-shaped magnetic flux density distribution that vertically deflects the three electron beams emitted from the electron gun. Then,
A color picture tube with good focusing characteristics can be easily constructed by taking advantage of the characteristics of the inexpensive self-convergence method and not degrading the quality of the image drawn on the phosphor screen.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing the structure of a color picture tube according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of the phosphor screen.

FIG. 3 is a diagram showing an arrangement of electron beam passing holes in a shadow mask of the color picture tube.

FIG. 4 is a diagram showing the configuration of a conventional color picture tube.

[Figure 5] Figure 5(a) is a diagram showing the influence of the horizontal deflection magnetic field in a conventional color picture tube on the shape of the beam spot, and Figure 5(b) is a diagram showing the influence of the vertical deflection magnetic field in the conventional color picture tube on the beam spot shape. It is a figure which shows the influence which it has on the shape.

[Explanation of symbols]

1...Panel 20...Phosphor screen 21...Shadow mask 22...Electron guns 26B, 26G, 26R...Three-color phosphor layer 27...Electron beam passing hole

Claims (1)

[Claims] 1. A phosphor screen comprising multiple sets of three-color phosphor dots, one set of three-color phosphor dots in a Δ arrangement, and the three-color phosphor dots are arranged in a line in the vertical direction; An electron gun that emits three electron beams arranged in a row passing on the same vertical plane, and an electron gun that is arranged opposite to the phosphor screen and selects the three electron beams emitted from the electron gun against the three-color phosphor dots. a shadow mask with a large number of circular electron beam passing holes formed therein;
A horizontal deflection coil that generates a horizontal deflection magnetic field with a mainly barrel-shaped magnetic flux density distribution that deflects the electron beam in the horizontal direction; and a vertical deflection coil with a mainly pincushion-shaped magnetic flux density distribution that deflects the electron beam vertically in the three electron beams emitted from the electron gun. 1. A color picture tube, comprising: a deflection device having a vertical deflection coil that generates a deflection magnetic field.