KR20030068596A - Electron gun for CRT - Google Patents

Abstract

PURPOSE: An electron gun is provided to achieve improved convergence characteristics by minimizing changes of thermal STC drift and electrostatic STC drift caused due to the rise of the internal temperature of the tube. CONSTITUTION: An electron gun comprises a cathode for emitting electron beams; a triode lens constituted by two or more electrodes for adjusting the amount of radiation of electron beam and accelerating electron beams to a screen; a pre-focus lens unit for focusing electron beams; and a main lens unit constituted by two or more electrodes for focusing electron beams on the screen. An elasticity control electrode is arranged on the opposed surfaces of the electrodes forming the main lens in such a manner that the elasticity control electrode is spaced apart from the rim portion forming a common hole for three electron beams. The electrodes constituting each of lens units are made of a plurality of members having different coefficients of thermal expansion.

Description

Electron gun for color cathode ray tube {Electron gun for CRT}

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, an electrode member for changing an electrode material of an electron gun radiating an electron beam for screen reproduction in a cathode ray tube so as to suppress thermal drift and electrostatic drift as much as possible. It is about.

1 is a cross-sectional view of a typical color cathode ray tube 1, in which each electrode of the electron gun for a color cathode ray tube can reach the fluorescent surface 3 by controlling an electron beam 19 emitted from three cathodes 8 in a constant intensity form. In order to be able to do so, the electron beams 19 are arranged in-line at regular intervals from each other to be perpendicular to the path through which the electron beam 19 passes.

The configuration is described in more detail with reference to FIG. 1 as follows.

Three cathodes 8 horizontally arranged side by side independently of each other, a first electrode 9 (G1) arranged to maintain a predetermined distance from the cathode to control hot electrons generated from the cathode, and the first electrode 9 The second electrode 10 (G2) and the third electrode (11; G3) arranged to be maintained at a predetermined interval to serve to pull out and accelerate the hot electrons gathered on the electron emitting material surface (not shown) of the cathode, and ), The fourth electrode 12 (G4), the fifth electrode 13 (G5), and the sixth electrode 14 (G6) are disposed in this order, and the funnel 6 is disposed on one side (the traveling direction side of the electron beam) of the sixth electrode. A shield cup 15 having a plurality of shield springs 16 fixed to the center of the neck portion 7 to serve as a ground for the graphite film coated on the inner surface of the panel and supported at the center of the neck portion 7 is disposed. have.

Different voltages are applied to the cathode 8 so as to obtain a constant current value such that the cut-off voltage of each electron gun is the same.

Therefore, when power is applied from the stem pin 18 to the heater 17 in the cathode 8 constituting the triode of the electron gun, when the heater generates heat, the hot electrons are emitted from the electron emission material applied to the tip of the cathode.

The hot electrons emitted as described above are controlled by the first electrode 9, which is a control electrode, and accelerated by the second electrode 10, which is an acceleration electrode, so that the second, 3, 4, 5 electrodes 10, 11, 12, 13 are controlled. The electron beam is focused and accelerated by the shear focusing lens formed between the first and second focusing lenses, and the electron beam is mainly focused by the fifth electrode 13, also called a focus electrode, which is a main lens forming electrode, and the sixth electrode 14, also called an anode electrode. It accelerates | stimulates, it passes through the shadow mask 4 provided in the inner surface of the fluorescent surface 3, and collides with the fluorescent surface 3, and produces light emission.

In addition, a deflection yoke 2 for deflecting the electron beam 19 emitted from the electron gun from the electron gun to the entire fluorescent surface 3 is positioned to implement a screen.

Particularly, each electrode of the electron gun is extended in the vertical direction of the tube axis according to the difference in thermal stability time and thermal expansion coefficient between the electrodes as the heater 17 generates heat and the temperature inside the tube increases with time. STC (collecting power of both beams to the center beam) which causes cohesion of the liver causes drift over time, which adversely affects the convergence characteristics.

2 is a graph showing the stable temperature and the settling time of each electrode. As shown in the figure, the initial change amount is large in order of G1, G2, G3, G4, G5, etc., but instead, the settling time arrives quickly.

3 is a diagram showing the path change of the electron beam according to the thermal expansion amount between the electrodes.

FIG. 4 is a diagram showing the influence of STC drift due to the covariance difference of each electrode, and FIG. 5 is a graph showing the change over time of STC drift over time.

As shown in FIG. 5, up to about 30 minutes is a variation of thermal STC drift caused by co-eccentricity due to a difference in thermal expansion coefficient due to heat of each pure electrode, and after 30 minutes, the side beam is pulled by a neck charge. It appears as a section where electrostatic drift occurs where under convergence occurs. In order to suppress initial thermal drift and current thermal drift, G1, G2, G4, etc. have a thermal expansion coefficient of about 9 * 10 ^-6 / ° C and use a low-expansion magnetic material, or bead parts of G1, G2 electrodes, etc. A method of modifying a structure such as a shape or forming a high resistance material on the neck inner wall of the high pressure portion is used.

Meanwhile, looking at the contents of US Patent No. 42730 (US42730), which is a previously applied patent, has a thermal expansion coefficient of less than 10 * 10 ⁻⁶ / ° C. on the G1, G2, and G4 electrodes to suppress STC drift, and G3 bottom ( Bottom), it is described that it is advantageous to have a structure having a thermal expansion coefficient of a magnetic substance of 20 * 10 ⁻⁶ / ° C., such as 9.5 * 10 ⁻⁶ / ° C., which is 52% nickel alloy, and 305 stainless steel.

However, when only a single raw material is used for each electrode component, the change in STC drift cannot be sufficiently suppressed only by the amount of thermal expansion inherent in each electrode. In addition, although the thermal expansion amount of the inner electrode opposite to the main lens part is small depending on the temperature and time, even if the amount of change is very small, the effect on the STC is considerably large. Therefore, a significant improvement effect of the STC drift cannot be expected without countermeasures. .

The present invention has been proposed to improve the above-mentioned conventional problems, and aims to maximize the electron gun efficiency for the cathode ray tube by minimizing the variation of STC drift by not using a single raw material when manufacturing each electrode.

1 is a cross-sectional view showing a typical color cathode ray tube.

Figure 2 is a graph showing the change with the stable temperature and time of each electrode of the electron gun.

3 is an effect diagram of the beam due to the covariance of each electrode.

4 is a diagram showing the influence of STC drift due to the covariance of each electrode.

5 is a graph of STC drift over time changes over time.

6 is a state diagram of a G5, G6 electrode configuration according to an embodiment of the present invention.

7 is a comparison of electron beam progress states before and after improvement of the G5 and G6 electrodes.

8A and 8B are graphs comparing changes in STC drift after and before improvement of the G5 and G6 electrodes.

9 to 11 illustrate various embodiments of the G5 and G6 electrodes.

12 is a comparison of electron beam progress states before and after improvement of a G4 electrode;

Figure 13 is an embodiment of a G1 or G2 electrode to which the present invention is applied.

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

1: color cathode ray tube 2: deflection yoke

3: fluorescent surface 4: shadow mask

5: Panel 6: Funnel

7: neck portion 8: cathode

9: first electrode G1 10: second electrode G2

11: third electrode G3 12: fourth electrode G4

13: fifth electrode G5 14: sixth electrode G6

13a, 14a: Rim 13b, 14b: Electrostatic field control electrode body

The object comprises a tripolar lens consisting of a cathode for emitting an electron beam, at least two electrodes for adjusting the radiation amount of the electron beam and accelerating the electron beam to the screen side, and at least two or more for focusing the electron beam a predetermined amount. It consists of a focus lens unit and a main lens unit composed of two or more electrodes for focusing the electron beam on the screen, and the electrostatic field is separated from the rim forming a ball common to the three electron beams on the mutually opposite surfaces of the main lens forming electrode In the electron gun for a cathode ray tube equipped with a control electrode body: The lens forming electrode can be achieved through a color cathode ray tube electron gun, characterized in that composed of a plurality of members each having a different coefficient of thermal expansion in the traveling direction of the electron beam.

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

In the exemplary embodiment of the present invention, as shown in FIG. 6, the fifth electrode 13 and the sixth electrode 14, which are the main lens forming electrodes, are positioned at a predetermined distance from the respective rims 13a and 14a. By constructing the electrostatic field control electrode bodies 13b and 14b located in two layers having different thermal expansion coefficients, an initial thermal STC drift and a long time STC drift were improved.

That is, the screen side of the end faces of the electrostatic field control electrode body 13b inside the G5 electrode to which the focus voltage is applied is manufactured so that the thermal expansion coefficient is smaller than that of the stem side, and the electrostatic field control electrode body 14b inside the G6 electrode is produced. The screen side of both cross-sections were designed to have a larger coefficient of thermal expansion than the stem side, so that the initial thermal STC drift and long time STC drift were improved.

The operation and effect thereof are shown in FIG. 7 in comparison with the related art, and the operation thereof is as follows.

In the case of the electrostatic field control electrode body using a single raw material having a high coefficient of thermal expansion, the temperature inside the tube rises, and when the main lens unit starts thermal expansion after a certain time, the amount of change increases in the vertical direction of the tube axis. The influence of the electrostatic field control electrode body 13b on which the focus voltage is applied and the electrostatic field control electrode body 14b on the high pressure is different when passing through the main lens unit, as shown in the left side of FIG. Volume increases and is not stable.

However, the thermal expansion coefficient on the screen side of the electrostatic field control electrode body 13b inside the G5 electrode to which the focus voltage is applied is made to be smaller than the thermal expansion coefficient on the stem side, and the electrostatic field control electrode body inside the G6 electrode ( If the thermal expansion coefficient on the screen side is made larger than the thermal expansion coefficient on the stem side of 14b), the temperature inside the tube rises over time, and the raw material on the side with the high thermal expansion coefficient expands due to the thermal expansion of the main lens unit. Even if the amount is large, since the amount of expansion on the side having the low coefficient of thermal expansion is small, the same effect as using a component having a single low coefficient of thermal expansion is shown as shown on the right side of FIG. The results before and after the improvement are shown graphically in FIGS. 8A and 8B.

In addition, the arrangement of the two types of thermal expansion coefficients of the G5 and G6 electrodes may have the same effect as that produced by the single low thermal expansion coefficient described above even when various forms are performed as shown in FIGS. 9 to 11. do.

Meanwhile, in another embodiment of the present invention, the STC drift variation can be minimized by the same action in the low voltage portion to which the focus voltage is applied and the electrode to which the potential, such as the voltage applied to the G2 electrode, is applied between another low voltage portion. This can be seen in FIG. 12.

That is, as shown in the drawing, two or more members having different thermal expansion coefficients are used as the raw material of the electrode to which the potential, such as the voltage applied to the acceleration electrode, is applied between the low low voltage portion to which the focus voltage is applied and another low voltage portion. In particular, the thermal expansion coefficient on the screen side of the cross section is made larger than the thermal expansion coefficient on the stem side, so that the temperature inside the tube rises over time, and even if the raw material having the high thermal expansion coefficient becomes large, the low thermal expansion The small expansion coefficient on the side with the coefficient gives the same effect as that produced by the single coefficient of thermal expansion.

Figure 13 shows a state in which the present invention is applied to the G1 electrode or G2 electrode.

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the material structure of the electrode of the present invention may be variously modified and implemented by those skilled in the art.

However, such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments shall fall within the appended claims of the present invention.

As described above, the present invention improves the convergence characteristics of the electron gun by minimizing the change of thermal STC drift and electrostatic STC drift caused by the time and the temperature inside the tube in the electron gun for the color cathode ray tube. Will be.

Claims (7)

A tripolar lens consisting of a cathode for emitting an electron beam, at least two electrodes for adjusting the radiation amount of the electron beam and accelerating the electron beam to the screen side, a prefocus lens portion consisting of at least two or more for focusing the electron beam a predetermined amount; And a main lens unit including two or more electrodes to focus the electron beam on a screen, and a static control electrode body is provided at a predetermined distance away from a rim forming a common ball of three electron beams on opposite surfaces of the main lens forming electrode. In electron gun for cathode ray tube: Electrodes constituting each of the lens portion is a electron gun for a color cathode ray tube, characterized in that made of a plurality of members each having a different coefficient of thermal expansion in the advancing direction of the electron beam. The method according to claim 1, An electron gun for a color cathode ray tube, wherein each of the different thermal expansion coefficients is an electrostatic control electrode body of a low voltage part to which a focus voltage is applied and an electrostatic control electrode body of a high voltage part to which a high voltage is applied. The method according to claim 2, The electrostatic control electrode body of the low voltage part to which the focus voltage is applied is manufactured so that the screen side has a smaller thermal expansion coefficient than the stem side, and the electrostatic control electrode body of the high voltage part to which high pressure is applied is manufactured to have a larger thermal expansion coefficient than the stem side. Electron gun for color cathode ray tube, characterized in that. The method according to claim 1, An electron gun for a color cathode ray tube, wherein each of the different thermal expansion coefficients is an electrode to which a potential equal to a voltage applied to an acceleration electrode is applied between another low voltage portion to which a focus voltage is applied. The method according to claim 4, An electron gun for a color cathode ray tube, characterized in that an electrode to which a potential equal to a voltage applied to an acceleration electrode is applied between another low voltage portion to which a focus voltage is applied is made such that the thermal expansion coefficient on the stem side is smaller than the screen side. The method according to claim 1, The different thermal expansion coefficients, the electron gun for a color cathode ray tube, characterized in that the control and acceleration electrode for controlling the radiation amount of the electron beam. The method according to claim 6, The control electrode and the acceleration electrode is electron gun for color cathode ray tube, characterized in that the thermal expansion coefficient of the stem side is made smaller than the screen side.