KR100198559B1 - A convergent electrode structure of the electron-gun used in the color crt - Google Patents

Abstract

[0001] The present invention relates to an electron gun used in a large-color TV or a high-definition industrial watercorrelation, and more particularly to a focusing electrode divided into first and second focusing electrodes, It is possible to reduce the horizontal focusing force of the electron beam passing through the quadrupole lens, that is, the electron beam passing through the quadrupole lens, that is, the horizontal focusing force of the electron beam, thereby eliminating the halo phenomenon occurring on the screen. .

Description

Focus electrode structure of electron gun for color cathode ray tube

[0001] The present invention relates to an electron gun used in a large-color TV or a high-definition industrial watercorrelation, and more particularly, To a focusing electrode of an electron gun for a color cathode-ray tube capable of reducing a halo phenomenon occurring on a screen by changing the shape of an electron beam passing hole to a transverse shape to weaken a horizontal direction acceleration force of an electron beam passing through a quadrupole lens.

As a constituent device of the electron beam gun, the electron beam emitted from the cathode is focused on the fluorescent surface of red, green and blue applied inside the front of the acelor so that the fluorescent material fluoresces in response to each electron beam, .

FIG. 1 is a cross-sectional view showing a schematic installation of an electron gun in a general color number correlation. The color number correlation includes an electron gun 2 for emitting an electron beam 1, and an electron gun 1 for deflecting the electron beam 1 in all directions A deflection yoke 3 for deflecting the electron beam 1, and a water corrector 4 for forming a pixel in response to the electron beam 1.

A screen 5 is provided in front of the water-level corrector 4, and a fluorescent screen 6 coated with red, green and blue phosphors is disposed on the inner surface.

At the rear of the screen 5, there is formed a funnel 7 converging rearwardly on the outer peripheral surface of the screen, and a tubular neck portion 8 having a predetermined diameter is formed in the converging portion.

An electron beam 1 emitted from the electron gun 2 is injected between the fluorescent screen 6 and the electron gun 2, A plate-shaped shadow mask 9 having a plurality of electron beam passing holes is fixed along the front inner circumferential surface of the funnel 7 so as to be selectively projected onto the fluorescent screen 6 of the red, green and blue.

FIG. 2 is a cross-sectional view showing a schematic structure of a color image capturing electron gun. The electron gun 2 is roughly divided into a triode portion 21 and a main lens portion 22. The triode portion 21 includes an embedded heater 23a, A control electrode 24 for controlling the thermoelectrons emitted from the cathode 23 and an accelerating electrode 25 for accelerating the thermoelectrons in the cathode 23 in the order of the cathode 23 for emitting hot electrons in accordance with the heat source of the cathode 23, And the main lens portion 22 is composed of a focusing electrode 26 for focusing the electron beam generated by the triode portion 21 and an anode 27 for accelerating the final acceleration.

Here, the control electrode 24 is grounded, a low voltage of 500 to 1000 V is applied to the accelerating electrode 25, a high voltage of 25 to 35 kV is applied to the anode 27, and a high voltage of 20 ~ 30% of the rated voltage.

In the electron gun for a color cathode-ray tube constructed as described above, an equipotential surface is formed by a voltage difference between the focusing electrode 26 and the anode 27 while a predetermined voltage is applied to each electrode, The electron beam 1 formed in the triode portion 21 is converged by the main lens and then passes through the electron beam passage hole of the shadow mask 9. [

The electron beam 1 having passed through the electron beam passage hole is converged at the center of the screen and strikes the fluorescent screen 6 to form a pixel.

The focusing of the electron beam 1 at the center of the screen is completed by the electrostatic lens due to the arrangement of the electron gun and the potential difference between the focusing electrode and the anode as described above. However, in order to sequentially scan the electron beam onto the screen, Deflection is required.

The following problems arise when deflecting the electron beam with the deflection yoke. The inline-type electron gun generally used in the color TV water can be arranged in a row in the same row as the neck 8, As shown in FIG. 3, in the vicinity of the deflection point at the time of right / left deflection, the center of the electron beam at the right and left sides of the screen is deviated The deviation becomes large.

In order to correct the deviation of the vertical pincushion distortion due to the deflection of the electron beam and the deviation of the electron beam in the horizontal direction, the vertical deflection coil of the toroidal winding and the horizontal deflection coil of the saddle winding, A paralla current is applied to the deflection yoke 3 formed by the deflection yoke 3 to form a barrel type magnetic field in the vertical coil and a pinchusion magnetic field is formed in the horizontal deflection coil to generate the fluorescent screen 6 according to the deflection angle, So as to compensate for the concentration deviation at the time of exposure.

However, this is because, when the electron beam is deflected to the peripheral portion, the over-focus component represented by the distance difference in the horizontal direction is offset from the divergence of the pincushion-type magnetic field by the deflection yoke, The over-focusing component due to the vertical distance difference causes a problem that the convergence of the barrel-shaped magnetic field due to the deflection yoke, that is, superposition of the over-focusing component, and the phase spreading phenomenon in the vertical direction, occurs severely.

More specifically, as shown in FIGS. 4a and 4b, a non-uniform magnetic field divided into a vertical barrel and a horizontal pincushion magnetic field includes a bipolar component that deflects the electron beam vertically and horizontally and a bipolar component that deflects the electron beam by the pincushion magnetic field Polarized components having horizontal focusing and vertical focusing of the electron beam by the barrel magnetic field. Particularly, since the quadrupole component serves as a kind of lens, when the electron beam is deflected to the peripheral portion on the screen, As a result, the focus is distorted in the longitudinal or transverse direction at the periphery of the screen, that is, the astigmatism is generated.

That is, a transverse elongated core, which is a phenomenon that diverges in the horizontal direction at the periphery of the screen and converges at high density in the vertical direction, and haze, which is a low-density phase expansion phenomenon, occurs at the periphery of the screen, Resulting in degraded resolution.

Even if the magnetic field is nearly uniform, astigmatism occurs because of the fine pincushion or the component of the barrel magnetic field. Therefore, when a non-uniform magnetic field is adopted, it is natural that the distortion at the peripheral portion of the screen becomes worse.

This is because the larger the aberration is, or the larger the deflection angle is, the larger the astigmatism becomes.

This is one of the problems to be solved when considering the tendency of consumers who prefer large water correlation and the deflection angle which increases with the size of water correlation.

In order to solve the above problem, there has been a method of correcting an astigmatism in synchronization with a deflection signal when an electron beam is deflected to the periphery of a screen. In general, a focusing electrode is divided into two to constitute first and second focusing electrodes And a quadrupole electrode provided between the electrodes to form a quadrupole lens, thereby correcting the electron beam in the quadrupole lens by the displacement of the electron beam distorted by the astigmatism to correct the astigmatism.

Japanese Unexamined Patent Publication No. 2-72546, which is an embodiment thereof, will be described with reference to Figs. 5a, 5b, 5c and 5d.

A first focusing electrode 261 disposed next to the triode portion for forming an electron beam and adapted to concentrate the electron beam and always receiving the same fixed voltage, and a second focusing electrode 261 disposed next to the first focusing electrode 261, And a variable voltage is applied to the second focusing electrode 262 so that a potential difference of about 300 V to 1000 V is generated depending on the deflection amount of the electron beam, As shown in the drawing, a quadrupole lens whose magnetic field is changed between the first and second focusing electrodes 261 and 262 according to the deflection amount of the electron beam is formed so that the astigmatism can be corrected.

The quadrupole electrodes for generating the quadrupole lens are arranged in such a manner that the opposite end faces 263 and 264 of the first and second focusing electrodes 261 and 262 and the second focusing electrode 263 and 264 are formed so as to allow three electron beams, One electron beam passage hole 265 formed in a rectangular shape on the first focusing electrode section 263 opposite to the electrode and three electron beam passage holes 262 formed in the end face of the second focusing electrode An internal electrode 267 disposed inside the first focusing electrode 261 and opposing to the inner surface of the first current collecting electrode stage 263 and receiving power supply; An electron beam passing hole 268 formed so as to allow each of the electron beams to pass therethrough and a horizontal partition wall 269 formed above and below the electron beam passing hole 266 of the second focusing electrode 262.

Particularly, since the horizontal partition 269 is inserted into the electron beam passage hole 265 of the first focusing electrode, when a potential difference is generated between the first and second focusing electrodes 261 and 262, A quadrupole lens can be formed between the electron beam passing holes 268 of the respective internal electrodes.

In the conventional electron gun which corrects astigmatism as a quadrupole electrode as described above, the electron beam 1 formed in the triode portion 21 is passed through the electron beam passing holes 265, 266 and 268 of the first and second focusing electrodes 26 and the internal electrode 267 Converges by the electrostatic lens according to the voltage difference between the first and second focusing electrodes 261 and 262 and the voltage of the anode 27, and then is deflected to each area of the screen by the deflection yoke 3.

At this time, when the electron beam 1 is scanned to the center of the screen and distortion of the electron beam does not occur, the same voltage is applied to the first and second focusing electrodes 261 and 262, so that a potential difference is not generated, The voltage of the second focusing electrode 262 changes dynamically according to the amount of deflection of the electron beam 1, that is, when the voltage of the second focusing electrode 262 changes to The voltage of the first focusing electrode 261 is higher than the voltage of the first focusing electrode 261 by about 300 V to 1000 V to cause a potential difference between the first and second focusing electrodes 261 and 262.

Thus, as described above, the quadrupole lens is operated to change the electron beam 1 to the longitudinal shape before the electron beam 1 passes through the main lens, so that it is possible to correct the transverse astigmatism caused by the deflection yoke .

However, in such a quadrupole lens, the shape of the electron beam passage hole of the electrode provided inside the focusing electrode 26 and the anode electrode 27 is changed to an EA (Elliptical Aperture) lens which is one kind of main lens developed by Hitachi In order to improve astigmatism removal and the degree of OBCV (Side Bean Convergence Variance), another type of main lens, LB (Large Aperture with Blade) The shape of the electron beam passing hole 271 in the center and the outer side is different from that of the EA lens in which the refractive index of the main lens for refracting the electron beam is the same as the electron beam passing hole shape in the center and the outside.

Therefore, the shape of the quadrupole lens according to the LB lens must be changed. If the quadrupole lens used in the EA lens is used without changing the structure of the quadrupole lens while using the conventional LB lens, The characteristics of the electron beam voltage are as shown in FIGS. 6B and 6C.

First, as shown in FIG. 6B, when the electron beam is deflected to the peripheral portion, the fixed voltage of the first focusing electrode is constant and the variable voltage of the second focusing electrode is exponentially increased do.

As shown in FIG. 6C, when the electron beam is deflected to the peripheral portion, the fixed voltage of the first focusing electrode gradually increases and the variable voltage of the second focusing electrode exponentially increases.

Considering that the first focusing electrode is involved in horizontal focusing and that the second focusing electrode is involved in divergence in the vertical direction, it can be seen that the action of the quadrupole lens on the outer beam, that is, the red electron beam is strong.

Such a phenomenon causes a halo phenomenon in which the electron beam is focused at the periphery of the screen and the shape of the electron beam is blurred in the horizontal direction, as shown in FIG. 6D.

Therefore, when the main lens is used as the L-B lens, it is necessary to weaken the horizontal focusing power outside the quadrupole lens.

As described above, according to the present invention, by changing the shape of the quadrupole electrode so that the action of the quadrupole lens can be changed according to the shape of the main lens such as the LB lens, the color cathode ray And it is an object of the present invention to provide a focusing electrode of a conventional electron gun.

In order to achieve the above object, the present invention is characterized in that, among the electron beam passing holes formed in the inner electrode, the horizontal width of the outer electron beam passage hole is made larger than the vertical width, And the electron beam focusing speed is weakened to compensate for the focusing of the outer electron beam in the main lens.

1 is a cross-sectional view illustrating a schematic installation of an electron gun in a general color number correlation.

FIG. 2 is a cross-sectional view showing a schematic structure of a general color image-capturing electron gun.

FIG. 3 is an example showing the deviation of the focus when the deviation of the electron beam due to the deflection upon deflection of the electron beam is not adjusted.

4A, 4B, and 4C are diagrams showing the distribution of the pincushion-type magnetic field in FIG. 4A and the shape in which the pixel formed by the electron beam is distorted in the horizontal direction in the non-uniform magnetic field of the deflection yoke.

4B is an exemplary diagram showing a distribution of the barrel-shaped magnetic field and a shape in which a pixel formed by the electron beam is distorted in the vertical direction.

4C is an exemplary diagram showing a state in which a pixel is distorted at the periphery of the screen due to astigmatism.

FIGS. 5A, 5B, 5C, and 5D show two conventional focusing electrodes of the conventional electron gun, and FIG. 5A is a vertical sectional view.

5b is a perspective view.

And FIG. 5C is a front view showing one end face of the first focusing electrode facing the second focusing electrode.

FIG. 5d shows an example in which a quadrupole lens is formed between the internal electrode and the second focusing electrode to change the electron beam into a longitudinal shape.

6A is a front view showing a conventional L-B lens.

6B is a graph of a center beam showing characteristics of an electron beam voltage measured on a screen when a quadrupole lens used in an E-A lens is used without changing a quadrupole lens while using an L-B lens.

Figure 6c is a graph of the side beam in Figure 6b.

FIG. 6d shows an example of the horizontal halo phenomenon occurring at the periphery of the screen when the quadrupole lens used in the E-A lens is used without changing the quadrupole lens while using the L-B lens.

FIGS. 7A, 7B, 7C and 7D show focusing electrodes of the electron gun for a color cathode ray tube of the present invention, and FIG. 7A is a longitudinal sectional view.

Figure 7b is a perspective view.

7C is another embodiment of the internal electrode.

7b is another embodiment of the internal electrode.

8 is a graph showing the correlation when the width of the inner electrode outer electron beam passage hole of the present invention is set to the X axis and the Y axis is set to a value obtained by subtracting the fixed voltage of the center beam from the three points of the peripheral portion of the screen .

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG.

A first focusing electrode 21 disposed next to the triode portion 1 forming three electron beams for focusing the electron beam and adapted to receive a fixed voltage and a second focusing electrode 21 disposed next to the first focusing electrode 21, And an electron beam passage hole is formed in the opposite ends 23 and 34 of the first and second focusing electrodes 21 and 22, do.

One electron beam passage hole 25 is formed in the first collector winding stage 23 so as to pass electron beams in common and the electron beam passes through the second collector stage terminal 24 A plurality of electron beam passing holes 26 are formed in the first focusing electrode 21 and a plurality of electron beam passing holes 26 are formed in the first focusing electrode 21, Three electron beam passing holes 28 are formed so as to allow the electron beams to pass through the electron beam passing holes 25 of the first focusing electrode, Barrier ribs 29 are provided so that a quadrupole lens is formed between the first and second focusing electrodes 21 and 22 when a variable voltage is applied.

As a means for weakening the action of the quadrupole lens with respect to the outer electron beam, a horizontal width of the electron beam outer side through hole 28side of the inner electrode is formed larger than a horizontal width of the electron beam central through hole 28center of the inner electrode It is long.

The electron beam central passage hole 28center of the internal electrode can be any shape within a range that does not affect the electron beam passing therethrough, but in the present invention, 7B, 7C, and 7D, it may be in the form of a keyhole formed by a combination of a rectangle, an ellipse, or a circle and a straight line.

A method for obtaining the optimum design value of the outside electron beam passage hole (28side) of the internal electrode will be described by dividing it into a case of a rectangle and a case of a keyhole.

First, the electron beam passing hole of a rectangular shape is formed by setting the vertical length of the outer passage hole to 4 mm, which is the same as the diameter of the central passage hole, and changing the horizontal direction to the focusing voltage It is possible to find the width Wh1 having the smallest change in the voltage, which is 4.6 mm, and the haze in the horizontal direction disappears here.

The experimental results are shown in FIG. 8, where the X axis represents the change of the width Wh1, and the Y axis represents the electron beam measurement value at the 3-point point of the screen (1 cm from the effective surface) Which is obtained by subtracting the electron beam specific value at the center of the screen.

The electron beam passing hole in the keyhole shape is formed so that the outer passing diameter Ds is equal to the central diameter Dc, the vertical length of the electron beam passing hole is fixed to 2.8 mm, The whistle voltage Wh3 that has the smallest change in voltage can be found by measuring the focusing voltage at the three points, which is 4.5 mm, and the haze in the horizontal direction disappears here.

The experimental results are also shown in FIG. 8, where the X-axis represents the change in the width Wh2.

Through the above-described experimental method, an optimal design value can be obtained even for an elliptical electron beam through hole, which is one of the embodiments of the present invention.

According to the present invention configured as described above, since the shape of the outer electron beam passage hole of the inner electrode is transversely elongated, the lens action of the electron beam passing through the quadrupole lens outer portion is weakened and the halo phenomenon Can be completely removed.

Since the shape of the outer electron beam passage hole formed in the inner electrode provided inside the first focusing electrode can be easily changed, the electron gun can be directly applied to production without changing the structure of the electron gun.

Claims (4)

A first focusing electrode to which an electron beam forming means and a focusing electrode for focusing an electron beam are applied and a second focusing electrode which is disposed next to the first focusing electrode and receives a variable voltage according to a deflection amount of the electron beam And one transverse electron beam passage hole through which electron beams commonly pass is formed on one end surface of the first focusing electrode facing the second focusing electrode, And a pair of upper and lower horizontal partition walls are provided on the upper and lower sides of the electron beam passage hole. When a variable voltage is applied to the second focusing electrode, four electron beam passing holes An electron gun for a color cathode ray tube in which an ultrarapic lens is formed, wherein an inner electrode having three electron beam passing holes is provided in the first focusing electrode, The ball shape is formed in a transverse shape so that the action force of the quadrupole lens acting on the central electron beam when the quadrupole lens is formed between the first and second focusing electrodes is stronger than the action force of the quadrupole lens acting on the outer electron beam A focusing electrode structure of an electron gun for a color cathode ray tube. The focusing electrode structure of an electron gun for a color cathode-ray tube according to claim 1, wherein an outer electron beam passage hole of the inner electrode is rectangular. The focusing electrode structure of an electron gun for a color cathode-ray tube according to claim 1, wherein the outer electron beam passage hole of the inner electrode has a rectangular shape in the horizontal direction and a circular shape in the vertical direction. The focusing electrode structure of an electron gun for a color cathode-ray tube according to claim 1, wherein an outer electron beam passage hole of the inner electrode is elliptical.