JP2003068230A - Cathode-ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain an electron beam spot size from being enlarged by improving an incident angle of an electron beam to a fluorescent screen at the periphery of the screen, in a wide angle deflection cathode-ray tube device. SOLUTION: In the cathode-ray tube device 1 comprising, at least, the fluorescent screen formed inside a panel 2, a funnel 3 connected to the panel 2, a neck 5 which is connected to the funnel 3 and has an electron gun 6 for emitting an electron beam, a deflection yoke 7 externally arranged between the funnel 3 and the neck 5, auxiliary horizontal deflection means 9, 9 are arranged in the vicinity of screen horizontal ends of the panel 2 and the funnel 3 to generate a vertical deflection magnetic field to a trace of an electron beam so that the electron beam trace can be curved in the direction of the fluorescent screen in the vicinity of horizontal ends of the screen by the auxiliary horizontal deflection means 9, 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide-angle deflection cathode ray tube device. Specifically, an auxiliary horizontal deflection means for generating a vertical deflection magnetic field with respect to the electron beam trajectory is attached near the horizontal edge of the screen of the panel and the funnel, and this auxiliary horizontal deflection means causes the electron beam trajectory near the horizontal edge of the screen. The present invention relates to a cathode ray tube device capable of suppressing enlargement of the electron beam in the peripheral portion of the screen due to wide-angle deflection by bending the lens in the direction of the fluorescent screen.

[0002]

2. Description of the Related Art Generally, a cathode ray tube, for example, a color cathode ray tube has a rectangular panel 2 as an envelope as shown in FIG.
1, a funnel-shaped funnel 22 connected to the panel 21, and a cylindrical neck portion 23 connected to the funnel 22.

On the inner surface of the panel 21, there is formed a phosphor screen 21a formed of a dot or stripe tricolor phosphor layer which emits blue, green and red light. A color selection mask 25 having a large number of electron beam openings is supported by a frame 26 so as to closely face the phosphor screen 21a.

An electron gun 27 for emitting an electron beam is built in the neck portion 23. Further, a deflection yoke 28 for deflecting and scanning the electron beam horizontally and vertically is arranged on the outer surface extending from the neck portion 23 of the envelope to the funnel 22.

In such a color cathode ray tube, the electron beam emitted from the electron gun 27, focused, and accelerated is deflected and scanned in the horizontal and vertical directions by the deflection magnetic field by the deflection yoke 28, and the electron beam of the color selection mask 25 is opened. The three-color phosphor layers which are selected by the holes and reach the phosphor screen 21a and which emit the blue, green and red light are correctly emitted to display a color image.

By the way, in general, a cathode ray tube is excellent in brightness and sharpness of a displayed image, but has a problem in that it is large in size, particularly large in depth. In particular, with the recent increase in the screen size of television receivers, the depth dimension of the cathode ray tube tends to become larger, and there is a further demand for shortening the overall length of the cathode ray tube.

Therefore, in order to shorten the total length of the cathode ray tube,
That is, in order to realize a thin cathode ray tube, various methods such as a flat cathode ray tube have been tried. Among them, the deflection angle θ of the cathode ray tube has been widened as a method of reliably reducing the depth without requiring a large change in the manufacturing process and requiring a small amount of new technology investment.

[0008]

However, increasing the deflection angle causes the following problems as well as the shortening of the total tube length. (1) Since the phosphor screen is obliquely irradiated with the electron beam in the periphery of the screen, the incident angle of the electron beam in the periphery of the screen is larger than that in the center of the screen, so that the spot size of the electron beam is enlarged and It has a bad influence on the characteristics of the cathode ray tube such as deterioration. FIG. 5 is a diagram showing the relationship between the deflection angle and the beam spot size. As shown by the solid line in FIG. 5, when the deflection angle exceeds 110 degrees, the electron beam spot diameter around the screen rapidly increases. I understand. (2) In the case of a color cathode ray tube, when the incident angle of the electron beam on the color selection mask increases, a part of the electron beam collides with the electron beam aperture wall of the color selection mask, and unnecessary reflected electrons cause a screen change. Unnecessary light emission is generated and the contrast of the displayed image is deteriorated. Although the electron beam aperture of the color selection mask is formed by etching, it is extremely difficult to form a hole capable of coping with an increase in the incident angle beyond the present condition because the shape of the hole is limited. (3) Due to the distortion of the deflection yoke for convergence correction, the size of the beam spot for irradiating the phosphor screen of the electron beam on the periphery of the screen becomes larger than that on the center of the screen. (4) In order to deflect the electron beam in a wider angle range,
The power consumption of the deflection yoke increases.

In order to improve this, there is a thin cathode ray tube incorporating an electrostatic auxiliary deflection function as shown in FIG. 8 (PCT US00-11640). The bulb of the thin cathode ray tube 30 includes a rectangular panel 31, a funnel-shaped funnel 32 connected to the panel 31, and a cylindrical neck portion 33 connected to the funnel 32. The electron beam 36 emitted from the electron gun 35 and arriving at the left and right ends of the screen is deflected by the deflection yoke 37, and then is deflected by the electrode plates (or kickback plates) 39a, 39b, 39c, 39d provided in the funnel 32. The orbit is bent, and in the vicinity of the left and right ends of the screen, it is bent toward the phosphor screen 31a, passes through the electron beam aperture of the color selection mask 40, collides with the phosphor on the phosphor screen 31a, and emits this phosphor. Let Electrode plates 39a, 39b, 39
A voltage slightly lower than the high voltage applied to the cathode ray tube 30 is applied to c and 39d, and the repulsive force caused thereby deflects the trajectory of the electron beam 36.

However, in a thin cathode ray tube incorporating such an electrostatic auxiliary deflection function, it is necessary to incorporate the electrostatic auxiliary deflection function into the cathode ray tube, which requires a drastic change in the manufacturing process and manufacturing equipment. This results in increased costs. Further, since the electrostatic auxiliary deflection function is incorporated in the cathode ray tube, there is a problem that it is necessary to supply a plurality of high voltages.

Therefore, the present invention is a wide-angle deflection cathode ray tube device, which can improve the angle at which the electron beam is incident on the phosphor screen in the periphery of the screen, and can suppress enlargement of the electron beam spot size. It is an object of the present invention to provide a cathode ray tube device that does not require high voltage supply.

[0012]

A cathode ray tube apparatus according to the present invention comprises a phosphor screen formed on an inner surface of a panel, a funnel connected to the panel, and an electron gun connected to the funnel and emitting an electron beam. In a cathode ray tube device including at least an internal neck and a deflection yoke externally provided from the funnel to the neck, a deflection magnetic field perpendicular to the orbit of the electron beam near the horizontal end of the screen of the panel and the funnel. Is provided, and the trajectory of the electron beam is bent toward the fluorescent screen in the vicinity of the horizontal edge of the screen by the auxiliary horizontal deflection means.

In the cathode ray tube device according to the present invention, the auxiliary horizontal deflection means for generating the vertical deflection magnetic field with respect to the orbit of the electron beam is provided near the horizontal end of the screen of the panel and the funnel. Thus, the trajectory of the electron beam can be bent toward the phosphor screen near the horizontal edge of the screen. Thereby, enlargement of the electron beam in the peripheral portion of the screen due to the wide-angle deflection can be suppressed, and deterioration of resolution and the like can be prevented.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a cathode ray tube according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a wide-angle deflection cathode ray tube device according to the present invention.
The glass bulb that constitutes the wide-angle deflection cathode-ray tube device 1 includes a panel 2 having a phosphor screen 2a on its inner surface, a funnel-shaped funnel 3 connected to the panel 2, and a cylinder connected to the funnel 3. The electron gun 6 is built in the neck portion 5. Funnel 3
A deflection yoke 7 is attached to the outer periphery of the neck portion side of the. Auxiliary deflection yokes 9 extending vertically are mounted near the left and right ends of the funnel 3. The auxiliary deflection yoke 9 will be described in detail later.

According to the present invention, an auxiliary deflection yoke 9 for generating a vertical deflection magnetic field with respect to the orbit of an electron beam is mounted in the vicinity of the screen horizontal end of the panel 2 and the funnel 3, and this auxiliary deflection yoke 9 allows the screen horizontal end. By bending the orbit of the electron beam in the vicinity in the direction of the fluorescent screen 2a, enlargement of the electron beam in the peripheral portion of the screen due to wide-angle deflection can be suppressed.

FIG. 2 is a plan partial sectional view of the cathode ray tube device. A color selection mechanism 11 is arranged to face the fluorescent surface 2a on the inner surface side of the panel 2. The phosphor screen 2a is formed by arranging three-color phosphors of red, blue, and green in a stripe shape, for example. The color selection mechanism 11 is composed of a color selection mask 12 arranged so as to face the fluorescent screen 2a on the inner surface of the panel 2, and a frame 13 to which the color selection mask 12 is attached. Since the cathode ray tube device 1 is wide-angle deflected, the funnel 3 is also formed in a wide-angle funnel shape, and the total length is shortened. Auxiliary deflection yokes 9 are mounted near the left and right ends of the funnel 3, respectively.

FIG. 3 is a schematic side view showing the auxiliary deflection yoke 9. The auxiliary deflection yoke 9 is made of a vertically elongated substantially C-shaped ferromagnetic material or a permanent magnet, and has both substantially C-shaped tip portions 9a and 9a 'and a column portion 9b that connects both tip portions 9a and 9a'. And the funnel 3 is sandwiched and mounted between the front end portions 9a and 9a '. The tip portions 9a and 9a 'for correcting the screen corner are formed in an elliptical shape and thick, and the column portion 9b for correcting the screen horizontal edge is formed in a thin shape. This is to make the correction amount of the screen corner larger than the horizontal end of the screen. Here, the screen horizontal edge refers to the left and right edges of the screen when the viewer views the cathode ray tube screen. Then, a magnetic field is generated from the lower tip portion 9a 'toward the upper tip portion 9a, and thereby a stronger magnetic field in the vertical direction of the screen is generated even at the screen corner portion. The deflection of the electron beam by the auxiliary deflection yoke 9 will be described in detail later.

FIG. 4 is a schematic plan view for explaining the principle of the cathode ray tube device according to the present invention. The electron beam 15 emitted from the electron gun 6 of the cathode ray tube is deflected by the deflection yoke 7,
The fluorescent screen 2 passes through the electron beam aperture of the color selection mask 12.
It collides with the phosphor of a and causes this phosphor to emit light.

The dotted line in FIG. 4 shows the trajectory of the electron beam arriving at the screen edge deflected only by the deflection yoke 7. In the conventional wide-angle deflection cathode ray tube, the electron beam is obliquely irradiated around the screen, so that the oblique cross section of the electron beam geometrically illuminates the screen around the screen. Becomes bloated.

Here, assuming that an ideal electron gun and a deflection yoke are realized, the enlargement of the beam spot size due to the geometrical structure ignoring spherical aberration will be described by the following mathematical expression. If the object point diameter of the electron gun is φ, the image magnification at the center of the phosphor screen is M, and the image magnification at the deflection angle α position is M ′, the beam spot diameter at the center of the phosphor screen is φc = Mφ. The beam spot diameters on the surface perpendicular to the beam traveling direction at the deflection angle α position are φe ′ = M′φ and M ′ = M / cos (α / 2). Therefore, since the beam spot diameter φe = φe ′ / cos (α / 2) on the phosphor screen arrival surface at the deflection angle α position, φe = φc / cos ² (α / 2) in the end. An outline of enlargement of spot size due to this geometric structure is shown in FIG.

FIG. 5 shows the relationship between the deflection angle and the beam spot size around the screen. The vertical axis shows the beam spot size on a relative scale, and the horizontal axis shows the deflection angle. As shown by the solid line in FIG. 5, the deflection angle is 1
It can be seen that if the angle exceeds 10 degrees, the electron beam spot diameter around the screen rapidly increases.

Therefore, as shown in FIG. 4, when a region for generating a vertical magnetic field is provided by the auxiliary deflection yoke 9 in the vicinity of the horizontal end of the screen of the cathode ray tube device 1, the electron beam arriving at the left and right ends of the screen is shown in FIG. As indicated by the solid line in FIG. 3, after being deflected by the deflection yoke 7, the auxiliary deflection yoke 9 passes through the vertical magnetic field generation region to receive a leftward force as shown in the drawing, and is bent toward the phosphor screen 2a, and the color is changed. Sorting mask 12
Through the aperture of the electron beam, and collides with the phosphor on the phosphor screen 2a to cause the phosphor to emit light.

The dotted line shown in FIG. 5 shows the relationship between the deflection angle and the beam spot size in the periphery of the screen when the electron beam reaches the fluorescent screen substantially perpendicularly even at the screen edge by the auxiliary deflection yoke 9. It has been shown that the beam spot size does not increase significantly as the deflection angle increases beyond 110 degrees. The magnetic field generated by the auxiliary deflection yoke 9 is basically not an AC magnetic field but a magnetic field static with respect to time may be generated, and a permanent magnet that does not consume power can be used.

Therefore, by providing a region near the horizontal edge of the screen of the cathode ray tube device 1 where the auxiliary deflection yoke 9 generates a magnetic field in the vertical direction of the screen, the orbit of the electron beam is bent toward the fluorescent screen 2a near the edge of the horizontal screen. By
It is possible to improve the geometric enlargement of the electron beam spot size around the screen, which is one of the problems in realizing a wide-angle deflection cathode ray tube. As a result, at present, the deflection angle of the cathode ray tube for wide-angle deflection is limited to 110 degrees in terms of electron beam spot size, but wide-angle deflection is possible up to about 140 degrees.

Since a permanent magnet that does not consume power can be used as the auxiliary deflection yoke 9, it is not necessary to supply an additional high voltage as in the case where the electrostatic auxiliary deflection function is incorporated in the cathode ray tube, and the power consumption is reduced. Can be suppressed.

It is possible to manufacture a thin cathode ray tube having a small depth without making a large change in the current cathode ray tube manufacturing process and manufacturing equipment and increasing the manufacturing cost.

Next, the auxiliary deflection yoke of the second embodiment will be described. FIG. 6 is a schematic side view showing the auxiliary deflection yoke according to the second embodiment. The auxiliary deflection yoke 17 according to the second embodiment is made of a vertically elongated substantially C-shaped magnetic body, and connects both substantially C-shaped tip portions 17a and 17a 'and both tip portions 17a and 17a'. It is formed of a pillar portion 17b, and the funnel 3 is mounted so as to be sandwiched between both tip portions 17a and 17a '. Tip portions 17a, 17a '
A coil 18 is wound around the column 17b, and a current is applied to the coil 18 so as to generate a magnetic field in synchronization with the vertical deflection frequency. The tip portions 17a and 17a 'for correcting the screen corner are formed in an elliptical shape and thick, and the column portion 17b for correcting the horizontal edge of the screen is formed in a thin shape. This is to make the correction amount of the screen corner larger than the horizontal end of the screen.

Therefore, the same effect as the auxiliary deflection yoke 9 of the first embodiment is produced, and the magnetic field is changed by the coil 18 to slightly shift the arrival position of the electron beam with respect to each position on the fluorescent screen 2a. It is possible to make fine adjustments to the screen.

In the first and second embodiments described above, the auxiliary deflection yokes 9 and 17 have a substantially C shape, but the present invention is not limited to this and may have a shape other than the C shape. Alternatively, a plurality of magnetic field generating members may be mounted above and below the horizontal end of the cathode ray tube.

[0030]

As described above, according to the present invention,
Since an auxiliary horizontal deflection means for generating a vertical deflection magnetic field with respect to the electron beam trajectory is provided near the screen horizontal edge of the panel and the funnel, this auxiliary horizontal deflection means causes the electron beam trajectory to fluoresce near the screen horizontal edge. It can be bent in the in-plane direction, so that enlargement of the electron beam in the peripheral portion of the screen due to wide-angle deflection can be suppressed and deterioration of resolution and the like can be prevented.

Since the current manufacturing process of cathode ray tubes and manufacturing facilities are not changed significantly, the manufacturing cost does not increase, and a thin and inexpensive cathode ray tube device with a small depth can be realized.

When a permanent magnet that does not consume power is used as the auxiliary horizontal deflection means, it is not necessary to supply an additional high voltage as in the case where the electrostatic auxiliary deflection function is incorporated in the cathode ray tube, and the power consumption is reduced. Can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a wide-angle deflection cathode ray tube device according to the present invention.

FIG. 2 is a plan partial cross-sectional view of a cathode ray tube device.

FIG. 3 is a schematic side view showing an auxiliary deflection yoke according to the present invention.

FIG. 4 is a schematic plan view illustrating the principle of the cathode ray tube device according to the present invention.

FIG. 5 is a diagram showing a relationship between a deflection angle and a beam spot size around a screen.

FIG. 6 is a schematic side view showing an auxiliary deflection yoke according to a second embodiment.

FIG. 7 is a plan sectional view showing a conventional cathode ray tube.

FIG. 8 is a view showing a thin cathode ray tube incorporating an electrostatic auxiliary deflection function.

[Explanation of symbols]

1 ... Cathode ray tube device, 2 ... Panel, 2a ... Phosphor screen, 3 ... Funnel, 5 ... Neck part, 6 ...
Electron gun, 7 ... Deflection yoke, 9 ... Auxiliary deflection yoke (auxiliary horizontal deflection means), 9a, 9a '... Tip portion,
9b ... Post portion, 12 ... Color selection mask, 17 ...
.Auxiliary deflection yoke (auxiliary horizontal deflection means) 17a, 17
a '... tip portion, 17b ... strut portion, 18 ... coil

Claims (4)

[Claims] 1. A fluorescent screen formed on an inner surface of a panel, a funnel connected to the panel, a neck internally provided with an electron gun connected to the funnel for emitting an electron beam, and the funnel to the neck. In a cathode ray tube device including at least an externally provided deflection yoke, auxiliary horizontal deflection means for generating a vertical deflection magnetic field with respect to the trajectory of the electron beam is provided in the vicinity of a horizontal end of the screen of the panel and the funnel, A cathode ray tube device, characterized in that the trajectory of the electron beam is bent toward the fluorescent screen in the vicinity of the horizontal edge of the screen by the auxiliary horizontal deflection means. 2. The cathode ray tube device according to claim 1, wherein the auxiliary horizontal deflection means is made of a substantially C-shaped magnetic body. 3. The cathode ray tube apparatus according to claim 1, wherein the auxiliary horizontal deflection means is a permanent magnet. 4. The cathode ray tube device according to claim 1, wherein the auxiliary horizontal deflection means is an electromagnetic coil.