KR19980014886A - Electron gun for color cathode ray tube - Google Patents

Abstract

A third aspect of the present invention provides an electron gun for a color cathode ray tube in which a plurality of third grid electrodes are divided to prevent focus deterioration at the periphery of the screen and electron beam transverse boom at the periphery of the screen due to use of the self-convergence deflection yoke.

The electron gun for a color cathode ray tube comprises a cathode for emitting electron beams, a first grid electrode and a second grid electrode for controlling and accelerating the electron beams, and a third, fourth and fifth grid electrodes and a bipotential In the cathode ray tube having the electron gun including the fifth and sixth grid electrodes forming the lens, the third grid electrode is divided into two electrodes to improve the resolution at the periphery of the screen.

Description

Electron gun for color cathode ray tube

The present invention relates to a color cathode ray tube (CCRT), and more particularly to an electron gun for a color cathode ray tube.

FIG. 1 is a vertical cross-sectional view of a conventional color cathode ray tube, which includes a panel 1 having an explosion-proof glass (not shown) fixed to the front surface thereof to maintain explosion-proof characteristics, A funnel 2 constituting a vacuum tube and having a neck portion 2a integrally formed on the rear portion thereof and a funnel 2 enclosing the electron beam 3 of red, Green, and blue applied to the inner surface of the panel 1 in a dot or stripe manner, and a fluorescent screen 5 having a predetermined interval from the fluorescent screen 5, A shadow mask 6 on which the panel 1 is fixed so as to perform color sorting and has a plurality of small holes of a pore shape or a circular shape on the surface thereof and a shadow mask 6 provided on the outer surface of the funnel 2, And a deflection yoke 7 for deflecting the deflection yoke.

Therefore, the electron beam emitted from the electron gun collides with the predetermined phosphor applied to the inner surface of the panel 1 through the fine holes of the shadow mask 6 serving as the color screening, so that the image signal applied to the electron gun 4 is reproduced do.

2 is a vertical sectional view and a cross sectional view showing a conventional In-Line type Uni-Bi electron gun in which a heater 9 embedded in a cathode 8 of an electron gun 4 is connected to a stem pin 10, the hot electrons are emitted from the heated cathode 8 by the generated heat.

The emitted three-color electron beam 3 radiates hot electrons from the cathode 8.

The emitted three-color electron beams 3 reach the screen through a plurality of electrode holes positioned in-line at regular intervals in the direction of the screen (Screen) from the cathode 8.

The process of reaching the electron beam 3 starting from the cathode 8 will be described in more detail as follows.

The electron beam 3 emitted from the cathode 8 of the electron gun 4 is irradiated to a beam forming region consisting of a first grid electrode 11, a second grid electrode 12 and a third grid electrode 13, (Uni-Potential Electro Static Lens) formed by a voltage difference that is appropriately controlled and accelerated by the third grid electrode 13, the fourth grid electrode 14, and the fifth grid electrode 15, Lt; / RTI >

Thereafter, the electron beam is focused again and accelerated by the Bi-Potential Electro Static Lens formed by the voltage difference applied to the fifth grid electrode 15 and the sixth grid electrode 16.

The electron beam passing through the electrostatic lens which is the main lens of the electron gun 4 is deflected by the influence of the magnetic field formed by the intensity of the current applied to the deflection yoke 7 provided so as to be wrapped around the outer surface of the funnel 2 do.

Thus, the electron beam 3 traveling along the determined path passes through the fine holes (not shown) of the shadow mask 6 provided at a predetermined interval from the fluorescent screen 5, collides with the fluorescent screen to emit the fluorescent material, do.

In order to make the electron beams 3 of blue, green, and red three colors coincide with each other at the center of the screen when passing through the respective electrodes as described above, an outer beam (an electron beam that implements blue and red) The hole passing through the hole is offset to the hole formed at the center, or the electrostatic lens is formed so that the path of the outer beam is directed toward the center beam (electron beam implementing green) by another suitable method.

As shown in the electron gun, a self-convergence deflection yoke 7 is used to uniformly match the electron beams 3 that emit blue, green, and red colors over the entire screen.

As shown in FIG. 3, the deflection yoke 7 forms a pin cushion magnetic field in the horizontal direction and a parallel magnetic field in the vertical direction, so that the three electron beams coincide with each other on the screen.

At this time, the respective electron beams of blue, green, and red are diverged in the horizontal direction according to the magnetic field formed by the deflection yoke 7, and are subjected to the connecting force in the vertical direction.

Halo phenomenon occurs when the electron beam is focused in the vertical direction due to the geometrical structure of the panel 1, and a very small halo phenomenon occurs in the horizontal direction as compared with the vertical direction.

Accordingly, research has been conducted for a long time to remove the halo phenomenon occurring in the vertical direction of the electron beam at the periphery of the screen projected on the screen. FIG. 4 shows an example of the halo phenomenon.

4, an electron gun according to the related art includes an electrode 15a to which a static voltage is applied (hereinafter referred to as a static electrode) 15a and an electrode to which a dynamic voltage is applied Quot;) 15b.

The stator electrode 15a is formed with a race h-shaped hole h through which three electron beams pass simultaneously to the dynamic electrode 15b side.

A plate-shaped electrode 18, in which three electron beam passing holes are formed, is positioned at a position spaced apart from the hole h of the race track shape by a predetermined distance.

Vertical barrier ribs 19 are fixed to one side of each electron beam passage hole that directs the dynamic electrode 15b in the plate electrode 18 located in the static electrode 15a.

A pair of horizontal barrier rib electrodes 20 parallel to the in-line direction of the electron beam passage hole formed on the static electrode 15a side are fixed to the dynamic electrode 15b.

At this time, a portion of the horizontal barrier rib electrode 20 fixed to the dynamic electrode 15b is configured to be inserted into the razor track-shaped hole h formed in the static electrode 15a.

Therefore, in the electrode configuration as described above, due to the difference between the constant voltage applied to the static electrode 15a and the voltage applied to the dynamic electrode as shown in Fig. 5, which is tuned to the deflection yoke 7, By forming the same quadruple lens between the static electrode 15a and the dynamic electrode 15b, an electron beam passing through the electrode is made into an elongated electron beam whose horizontal direction is smaller than the vertical direction.

When the electron beam is deflected to the periphery of the screen due to the deflection yoke 7 of this electron gun, the over-focusing phenomenon (the phenomenon in which the focal length is shortened) in the vertical direction of the electron beam by the deflection magnetic field is compensated. The halo phenomenon can be eliminated.

The conventional electron gun for a color cathode ray tube fails to compensate for the increase in the horizontal direction of the electron beam at the periphery of the screen generated by the self-convergence yoke.

In addition, a vertical length of a smaller electron beam in which halo is removed in the vertical direction causes a Moire phenomenon in a low current region.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a plasma display panel in which a plurality of third grid electrodes are divided into a plurality of sub- And it is an object of the present invention to provide an electron gun for a color cathode-ray tube capable of suppressing horizontal shrinkage.

1 is a longitudinal sectional view showing a general color cathode ray tube,

FIG. 2 is a longitudinal sectional view and a cross-sectional view showing a conventional in-line type Univ.

3 is a schematic view showing the horizontal and vertical deflection magnetic fields of the screen,

4 is a longitudinal sectional view and a cross-sectional view of an electron gun to which a conventional dynamic voltage is applied,

FIG. 5 is a waveform diagram showing a dynamic voltage applied to a screen in the configuration of FIG. 4,

6 is a potential distribution diagram due to a voltage difference between the static electrode and the dynamic electrode,

7 is a longitudinal sectional view and a cross-sectional view showing an electron gun for a color cathode ray tube according to the present invention.

Description of the Related Art [0002]

3: electron beam 4: electron gun

7: deflection yoke 8: cathode

11: first grid electrode 12: second grid electrode

13: third grid electrode 13a, 13b: electrode

14: fourth grid electrode 15: fifth grid electrode

15a: Static electrode 15b: Dynamic electrode

16: sixth grid electrode

According to an aspect of the present invention, there is provided an electron gun for a color cathode ray tube, comprising: a cathode for emitting electron beams; a first grid electrode and a second grid electrode for controlling and accelerating the electron beams; 3, 4 and 5 grid electrodes, and fifth and sixth grid electrodes forming a bipotential lens, wherein the third grid electrode is divided into two electrodes, So that the resolution of the display device can be improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of an electron gun for a color cathode ray tube according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 7 is a longitudinal sectional view and a cross-sectional view showing an electron gun for a color cathode ray tube according to the present invention. FIG. 7 is a cross-sectional view of a cathode ray tube Third, fourth, and fifth grid electrodes 13 (see FIG. 1) forming a uniform potential lens to appropriately focus and accelerate the electron beam so that the phosphor is coated and focused on the screen 14, 15), a second grid electrode (12, 14, 15), a second grid electrode (15, 16) disposed on one side of the fourth grid electrode and forming a bipotential lens and sequentially arranging the fifth and sixth grid electrodes And the fourth grid electrode 14 are divided into at least two or more electrodes 13a and 13b so that the divided electrodes are spaced apart from each other.

The fifth grid electrode 15 is divided into a static electrode 15a and a dynamic electrode 15b and sequentially arranged. The vertical grid electrode 15 in the vertical direction, which is an electron beam path of the static electrode 15a, ).

In addition, in the horizontal direction, which is an electron beam path of the dynamic electrode 15b, the horizontal barrier electrode 20 is fixed and a variable voltage is applied to the dynamic electrode 15b in synchronization with the deflection yoke 7.

Further, the connection is made to the static electrode 15a of the fifth grid electrode 15 so that a connection voltage is applied to the first electrode 13a of the third grid electrode formed in a divided manner.

The electron beam passage hole of the second electrode 13b of the third grid electrode is axisymmetric and is connected to the dynamic electrode 15b of the fifth grid electrode so that a variable voltage is applied to the deflection yoke 7 .

In addition, among the third grid electrodes formed in a divided shape, the first electrode 13a formed in a plate-like shape has a horizontally long length that is longer than the vertical length, and two of the third grid electrodes are welded The process of the plate-shaped electrode on the cathode 8 side of the second electrode 13b constituted is a longitudinal type in which the length in the vertical direction is longer than the length in the horizontal direction.

The operation of the electron gun for a color cathode ray tube according to the present invention will be described as follows.

As the voltage applied to the dynamic electrode 15b of the fifth grid electrode increases in synchronism with the deflection yoke 7, the asymmetric structure between the static electrode 15a and the dynamic electrode 15b causes the first quadrupole A lens is formed.

Also, as the voltage applied to the dynamic electrode 15b increases, the intensity of the bipotential lens formed between the fifth grid electrode 15 and the sixth grid electrode 16 becomes weak.

In addition, as the voltage applied to the second electrode 13b of the third grid electrode increases, a second quadrilar lens is formed due to the asymmetric structure between the electrodes 13a and 13b constituting the third grid electrode .

As the voltage applied to the second electrode 13b of the third grid electrode increases, the potential of the third grid electrode 13, the fourth grid electrode 14, and the fifth grid electrode 15, The intensity of the lens is increased.

The operation of the lens formed by applying the variable voltage tuned to the deflection yoke 7 to the dynamic electrode 15b and the second electrode 13b of the third grid electrode will now be described in detail.

Since the first quadrupole lens converges the electron beam in the horizontal direction and diverges in the vertical direction, the vertical direction of the electron beam converged at the rotation peripheral portion by the self-convergence yoke is appropriately diverted in advance in the electron gun, .

The bi-potential lens whose intensity is weakened allows an accurate image to be formed on the screen in the horizontal direction of the electron beam focused by the first quadrupole lens.

As the intensity of the bipotential lens is weakened, the distance from the bipotential lens to the object point increases and the angle of incidence of the electron beam incident on the binoculars must be decreased. Therefore, the intensity- Lens so as to form a smaller electron beam on the screen.

Also, since the second quadrupole lens diverges the electron beam in the horizontal direction and focuses the electron beam in the vertical direction, the self-convergence yoke and the first quadrupole lens and the bi-potential lens that weakens the intensity are used And serves to compensate for the horizontal size of the increased electron beam and the vertical size of the reduced electron beam.

As described above, according to the electron gun for a color cathode ray tube according to the present invention, there is an effect of compensating for a transversely-stretched beam characteristic at the periphery of a screen generated by a self-convergence yoke.

In addition, there is also an effect that the moiré phenomenon in the low current region is removed and the horizontal direction length of the electron beam in the entire screen is made smaller, thereby increasing the resolution.

Claims (5)

A first grid electrode and a second grid electrode for controlling and accelerating the electron beams, a third, a fourth, and a fifth grid electrodes forming a universal lens, and a second electrode for forming a bipotential lens 5. A cathode-ray tube having an electron gun including grid electrodes, Wherein the third grid electrode is divided into two electrodes so as to improve the resolution at the periphery of the screen. The method according to claim 1, Wherein the first electrode of the third grid electrode is electrically connected to the electrode of the fifth grid electrode to which a constant static voltage is applied. The method according to claim 1, Wherein the second electrode of the third grid electrode is electrically connected to an electrode to which a voltage that is varied and tuned to the deflection yoke of the fifth grid electrode is applied. The method according to claim 1, Wherein the first electrode of the third grid electrode has a pore shape of a transverse elongated shape. The method according to claim 1, And the second electrode of the third grid electrode is axially symmetric in a longitudinal shape.