KR20010084693A - Electron gun in cathode ray tube - Google Patents

Abstract

PURPOSE: An electron gun for color CRT is provided to correct screen distortion and coma aberration by using a reduced number of focusing electrodes. CONSTITUTION: An electron gun comprises a cathode for emitting electrons; a control electrode for controlling electrons emitted from the cathode; an accelerating electrode for accelerating electrons emitted from the cathode; and a plurality of focusing electrodes(605,606) for focusing electrons. The focusing electrodes have holes(701,702) for applying of variable voltage and passage of electron beam, and holes have one or more variable electrodes at the center of which corresponds to electron beam. The variable electrode facing the hole of the focusing electrode includes a cup-shaped fixed electrode to which a fixing voltage is applied. The fixed electrode has a hole, the variable electrode side center of which is shifted in a horizontal or vertical direction from the center of hole of the variable electrode.

Description

Electron gun in cathode ray tube

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to provide an electron gun for a color cathode ray tube capable of correcting screen distortion and coma aberration of an electron beam by reducing the number of electrodes.

1 is a schematic diagram of a typical colored cathode ray tube.

Referring to FIG. 1, a cathode ray tube generally includes a stem pin 101 to which a voltage is applied, a cathode 102 for emitting electrons, and an element for controlling / accelerating electrons emitted from the cathode and forming a lens. A plurality of control / acceleration / focus electrodes 103 to 111, a panel 117 to which light emitting phosphors are applied, and a funnel connected to the panel 117 to maintain the inside thereof in a vacuum ( funnel 112, a shield cup 113 for fixing the electron gun to the neck portion of the funnel 112 while electrically connecting the electron gun and the funnel 112 to the upper portion of the electrode, A deflection yoke 114 for uniformly deflecting the electron beam 115 formed by the electrons emitted from the electron gun to the entire panel 117 and a color spaced at a predetermined distance from the panel 117. It consists of a shadow mask (116) for screening.

The operation of the cathode ray tube having the above configuration will be briefly described.

First, when a voltage is supplied to the stem pin 101, heat is applied to the cathode 102, and electrons are emitted from the cathode 102 to which the heat is applied. The emitted electrons are focused / accelerated by the first electrode 103 to the sixth electrode 108. The electron beam 115 formed by the electrons focused and accelerated is deflected by the deflection yoke 114 and evenly irradiated onto the entire panel 117, and the electron beam 115 is a shadow mask provided in front of the panel 117. 116 passes through and collides with the phosphor applied to the panel 117 to emit light.

On the other hand, as the screen is enlarged and planarized, distortion of the electron beam becomes more serious at the periphery of the screen, resulting in a decrease in resolution.

In general, when a deflection yoke having a uniform magnetic field is used, three electron beams do not coincide at the front of the screen. In order to match the electron beam at the front of the screen, a self-convergence deflection yoke that forms a non-uniform magnetic field is employed. That is, when the self-convergence deflection yoke having a non-uniform magnetic field as shown in FIGS. 2A and 2B is used, the distance of each electron beam may be changed to compensate for the difference, thereby making the electron beam coincide in front of the screen. The magnetic field is subjected to the diverging force in the horizontal direction and the focusing force in the vertical direction, and the core 201 and the electron beam where the electron beam is concentrated at the periphery of the screen by the force of the electron beam and the geometry of the panel 117. A portion of the haze 202 that is not dense is generated to cause resolution deterioration at the periphery of the screen. In order to solve such a degradation of the resolution, a non-polar magnetic field is inserted by inserting a quadrupole lens corresponding to the deflection yoke in the electron gun, that is, a quadrupole lens that focuses the electron beam in the horizontal direction and emits the electron beam in the vertical direction. Although a method of canceling the generated quadrupole components has been adopted, satisfactory solutions due to the flatness and size of the screen have not been achieved.

In addition, as shown in FIG. 3, the screen distortion phenomenon occurs when the deflection distance of the electron beam is shortened at the centers of the top and bottom of the screen and at the centers of the left and right sides. In order to correct the problem, the center of the hole of the electron beam is moved, and a method of applying a variable voltage to the electrode in synchronization with the deflection yoke is briefly described with reference to FIGS. 3 to 5.

In the control electrode 103, the acceleration electrode 104, and the plurality of focusing electrodes 105 to 110 and the anode 111 for focusing and electrons of the electron gun, the focusing electrodes 105 to 110. Is composed of six first to sixth focusing electrodes, and applies a voltage varying in synchronization with the deflection yoke to the second focusing electrode 106 and the fourth focusing electrode 108, and the first focusing electrode 105. A constant voltage is applied to the third focusing electrode 107 and the fifth focusing electrode 109.

Herein, the variable voltage for correcting the screen distortion phenomenon in the vertical direction is a cap shape that is small at the left and right sides of the screen, the largest at the center, and the left and right symmetry at the center during the horizontal period, and each vertical period. While the amplitude is the largest on the left side of the screen and decreases toward the center, the waveforms at the top and bottom of the screen are rotationally symmetrical 180 ° from the center of the screen, and the waveform of the variable voltage to correct the screen distortion in the horizontal direction is The horizontal period is the largest on the left side of the screen and decreases toward the center and is 180 ° rotationally symmetrical from the center, while the amplitude during each vertical period is small at the top and bottom of the screen and gradually increases to the largest voltage in the center. The order of the second focusing electrode 106 and the fourth focusing electrode 108 to be applied is not limited.

On the other hand, the hole 402 through which the three electron beams of the second focusing electrode 106 pass is formed in front of and behind the first focusing electrode 105 and the second focusing electrode 106 of the third focusing electrode 107. The shape of the hole 402 of the second focusing electrode 106 is formed in an elliptical shape so that the center in the vertical direction is moved downward with respect to the side holes 401 and 403.

In addition, the holes 404 through which the three electron beams of the fourth focusing electrode 108 pass are formed at the front and back of the third focusing electrode 107 and the fourth focusing electrode 108 of the fifth focusing electrode 109. The shape of the hole 404 of the fourth focusing electrode 108 is formed in an elliptical shape so that the center in the horizontal direction is moved to the left side with respect to the side holes 403 and 405.

Meanwhile, a variable voltage (FIG. 5A) is applied to the second focusing electrode 106 to correct the screen distortion phenomenon in the vertical direction, and the screen distortion phenomenon in the horizontal direction is applied to the fourth focusing electrode 108. A variable voltage (FIG. 5B) is applied to correct the voltage, and a constant voltage is applied to the first focusing electrode 105, the third focusing electrode 107, and the fifth focusing electrode 109. Therefore, the second focusing electrode 106 is applied. The voltage applied to is the highest in the center of the top of the screen, the lowest in the center of the bottom, the hole 402 through which the electron beam of the second focusing electrode 106 passes in the elliptical shape of the center is moved downward Since the electrons are deflected in the center of the top of the screen and the center of the bottom of the screen to correct the screen distortion in the vertical direction, the voltage applied to the fourth focusing electrode 108 is the top and bottom of the screen. Small in, largest in left and right middle part, fourth Since the hole 405 through which the electron beam of the inner electrode 108 passes has an elliptical shape and its center is moved to the left side, a large amount of electrons are deflected at the center of the left and right sides of the screen, so that the screen distortion is horizontal. ) Can be corrected.

On the other hand, in the above-described movement of the center of the hole through which the electron beam passes and a method of applying a variable voltage thereto, the electron beam may pass through the center of the main focusing lens by changing the center through which the electron beam passes. The electron beam generates coma on the screen. Therefore, the shorter the distance that the electron beam passes through the focusing electrode, the better.

However, when the screen distortion is corrected by using a uni-type electrode in which the same voltage is applied to both sides and different voltages are applied therebetween, to compensate for the horizontal and vertical screen distortion, At least five focusing electrodes of an electrode for applying a variable voltage in the horizontal direction and an electrode for applying a fixed voltage to both sides thereof are required. Therefore, the distance that the electron beam passes through the focusing lens is long, which causes a coma aberration phenomenon in which the focus of the electron beam is shifted on the screen.

In addition, since the centers of the holes of the second focusing electrode and the fourth focusing electrode, which are plate-shaped electrodes to which a variable voltage is applied, are moved, there is a problem in that the assembly of the electron gun is difficult due to the flow of the electrodes.

The present invention has been made to solve the above problems, and instead of the uni-type electrode, the shape of both holes of one electrode having a cup shape is different, and a bi-coupling of different voltages is applied to two adjacent electrodes. It is an object of the present invention to provide an electron gun for a color cathode ray tube which can reduce the number of focusing electrodes by forming an electrode structure of the form bi, and which can correct screen distortion even with the reduced electrode.

1 is a schematic view of a typical colored cathode ray tube.

2A shows a pincushion type magnetic field of a self-convergence deflection yoke.

2b shows a barrel-shaped magnetic field of a self-convergence deflection yoke.

3 is a view showing a screen distortion phenomenon of a typical color cathode ray tube.

4 is a view showing an electrode of a conventional electron gun for colored cathode ray tubes.

5A is a waveform of a variable voltage for correcting picture distortion in the vertical direction.

5B is a waveform of a variable voltage for correcting picture distortion in the horizontal direction.

6 is a view showing an electron gun for a color cathode ray tube according to the present invention.

7 is a view showing the electrode of the electron gun for the color cathode ray tube according to the present invention.

<Explanation of symbols for the main parts of the drawings>

101 ... Stempin 102, 602 ... Cathode

103, 603 ... control electrode 104, 604 ... acceleration electrode

105, 605 ... first focusing electrode 106, 606 ... second focusing electrode

107, 607 ... third focusing electrode 108, 608 ... fourth focusing electrode

109, 609 ... fifth focusing electrode 110, 610 ... fifth focusing electrode

111 ... anode 112 ... funnel

113 ... shield cup 114 ... deflection yoke

115..E-beam 116 ... shadow mask

117 Panel 201 Core

202.Haze

In order to achieve the above object, a color cathode ray tube electron gun according to the present invention is a color cathode ray tube electron gun including a plurality of electrodes for forming a lens that controls and accelerates the electron beam, a variable voltage is applied to the The hole through which the electron beam passes through includes at least one variable electrode whose center coincides with the center of the electron beam, and one of the holes facing the hole of the variable electrode is horizontal and the other is vertical. At least two cup-shaped fixed electrodes moved from a center of the hole of the variable electrode and to which a fixed voltage is applied.

Here, the waveform of the variable voltage applied to the variable electrode whose center is moved perpendicularly to the center of the hole of the fixed electrode is small at the left and right sides of the screen during the horizontal period, the largest at the center, and symmetrical at the center. Cap shape, the amplitude during each vertical period is the largest on the left side of the screen and decreases toward the center, the waveform at the top and bottom of the screen is 180 ° rotationally symmetrical from the center of the screen, and the center and horizontal of the hole of the fixed electrode The waveform of the variable voltage applied to the variable electrode whose center is moved is the largest on the left side of the screen during the horizontal period and decreases toward the center, and is 180 ° rotationally symmetrical at the center thereof. The amplitude is small at the top and bottom of the screen, and gradually increases, preferably at the center.

In addition, the variable electrode is preferably made of a plate shape.

According to the present invention, it is possible to construct an electron gun capable of correcting the screen distortion phenomenon with a small number of focusing electrodes, thereby shortening the distance through which the electron beam passes through the focusing electrode, thereby preventing coma aberration of the electron beam. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

6 is a view showing an electron gun for a color cathode ray tube according to the present invention, Figure 7 is a view showing an electrode of the electron gun for a color cathode ray tube according to the present invention.

6 and 7, the electron gun for the color cathode ray tube according to the present invention, like the conventional color cathode ray tube electron gun, controls the cathode 602 for emitting electrons and the electrons emitted from the cathode 602. The control electrode 603, the acceleration electrode 604 for accelerating the electrons, and a plurality of focusing electrodes 605 to 609 and the anode 610 for focusing the control / accelerated electrons.

However, the electron gun for the color cathode ray tube according to the present invention, the plurality of focusing electrodes, the variable voltage is applied and the hole through which the electron beam passes therein includes at least one variable electrode whose center coincides with the center of the electron beam, the variable At least two of the cup-shaped fixed electrodes facing one of the holes facing each other are horizontally and the other vertically moved from the center of the hole of the variable electrode and having a fixed voltage applied thereto. Is characterized by different features.

That is, as shown in the drawing, of the focusing electrodes 605 to 609, the second focusing electrode 606 and the third focusing electrode 607 are plate-shaped electrodes, and the holes through which the electron beams pass ( The centers of the 702 and 703 coincide with the center of the electron beam and consist of a variable electrode to which a variable voltage is applied, and the first focusing electrode 605 and the fourth focusing electrode 608 have holes through which the electron beam passes. The electrode hole 701 of the first focusing electrode 605 and the second focusing electrode 606 side of the first focusing electrode 605 has a vertical direction than the hole 702 of the second focusing electrode 606 facing the cup. The hole 704 of the third focusing electrode 607 side of the fourth focusing electrode 608 has an elliptical shape so that its center is moved upward. It has an elliptical shape so that its center is moved to the right side of the horizontal direction.

In addition, the first focusing electrode 605 and the fourth focusing electrode 608 are fixed electrodes to which a fixed voltage is applied, and the first focusing electrode 605 and the second focusing electrode having holes moved in the vertical direction. In order to correct the screen distortion in the vertical direction at 606, a variable voltage (FIG. 5A) is applied to the second focusing electrode 606, and a fourth focusing electrode 608 having a hole whose center is moved in the horizontal direction. A variable voltage (FIG. 5B) is applied to the third focusing electrode 607 in order to correct the horizontal picture distortion in the third focusing electrode 607.

Here, the waveform of the voltage for correcting the screen distortion phenomenon in the vertical direction applied to the second focusing electrode 605 among the variable electrodes is small on the left and right sides of the screen during the horizontal period, the largest in the center and the center thereof In the symmetrical cap shape, the amplitude during each vertical period is the largest on the left side of the screen and decreases toward the center, and the waveforms at the top and bottom of the screen are rotationally symmetrical 180 ° from the center of the screen (see FIG. 5A). The waveform of the voltage for correcting the screen distortion phenomenon in the horizontal direction applied to the third focusing electrode 607 is the largest on the left side of the screen during the horizontal period and decreases toward the center and rotates 180 ° from the center thereof. The amplitude during each vertical period is small at the top and bottom of the screen and gradually increases to the largest in the center (see FIG. 5B).

On the other hand, referring to the operation of the electron gun for the color cathode ray tube according to the present invention having the configuration as described above, the electron beam is emitted from the cathode 602 is controlled and accelerated through the control electrode 603, the acceleration electrode 604, The first focusing electrode 605 passes through the fourth focusing electrode 608 sequentially.

At this time, the screen distortion phenomenon in the vertical direction of the hole 701 of the second focusing electrode 606 side of the first focusing electrode 605 and the vertical direction applied to the second focusing electrode 606 is shown. By the voltage to be calibrated, when the electron beam is deflected by the deflection yoke, it is most deflected at the center of the screen and gradually less deflected to both sides during the horizontal period, and the largest and gradually at the top and bottom of the screen during each vertical period. It is reduced, so that it is less deflected at the center part, and thus it is possible to correct the vertical picture distortion phenomenon (V).

In addition, the movement of the center of the fourth focusing electrode 608 in the horizontal direction of the hole 704 of the third focusing electrode 607 and the distortion of the screen in the horizontal direction of the third focusing electrode 607 are corrected. When the electron beam is deflected by the deflection yoke, it is most deflected on both sides of the screen during the horizontal period and gradually deflected toward the center, and less at the top and bottom of the screen during each vertical period. Towards the center of the screen, the deflection becomes more and more, and the horizontal distortion can be corrected.

That is, the center of the upper and lower portions of the screen is shortened by moving the center of the variable voltage applied to correct the screen distortion in the vertical and horizontal directions and the hole of the electrode to which the variable voltage is applied (V). The center of the left and right sides is shortened (H) to correct the screen distortion phenomenon.

As described above, the electron gun for the color cathode ray tube according to the present invention is an electron gun that can correct the screen distortion with a small number of focused electrodes by forming a bi-type electrode structure for applying different voltages to two adjacent electrodes. By shortening the distance that the electron beam passes through the focusing electrode, it is possible to eliminate the coma aberration phenomenon that the electron beam is out of focus on the screen. In addition, the plate-shaped electrode has the advantage that it is easy to assemble the electron gun does not move the center of the hole therein.

Claims (4)

An electron gun for a cathode ray tube comprising a plurality of electrodes for forming a lens for controlling and accelerating and focusing an electron beam, The hole through which the variable voltage is applied and the electron beam passing therein includes at least one variable electrode whose center coincides with the electron beam, and the at least one electrode facing the hole of the variable electrode has a cup shape to which a fixed voltage is applied. And a fixed electrode, wherein the center of the variable electrode side hole of the fixed electrode is moved horizontally or vertically from the hole center of the variable electrode. The method of claim 1, The waveform of the variable voltage applied to the variable electrode adjacent to the fixed electrode in which the hole is eccentric in the vertical direction is a cap shape that is small at the left and right sides of the screen and is largest in the center and symmetrical at the center during the horizontal period. The amplitude during each vertical period is the largest on the left side of the screen and decreases toward the center, and the waveform at the top and bottom of the screen is rotationally symmetrical 180 ° from the center of the screen. The method of claim 1, The waveform of the variable voltage applied to the variable electrode adjacent to the fixed electrode in which the hole is eccentric in the horizontal direction is the greatest on the left side of the screen and decreases toward the center during the horizontal period, and is rotated by 180 ° from the center thereof. Electron gun for color cathode ray tube, characterized in that the amplitude during one vertical period is small at the top and bottom of the screen and gradually increases to the largest in the center. The method of claim 1, The variable electrode is a electron gun for a color cathode ray tube, characterized in that consisting of a plate-like form.