KR920001982Y1 - Multi-step focusing electron gun of crt - Google Patents

Abstract

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Description

Multi-Stage Focusing Gun for Cathode Ray Tubes

1 is a cross-sectional view showing a voltage application state of a conventional multi-stage focused electron gun.

2 is a sectional view showing a multi-stage focused electron gun according to the present invention, showing a voltage applied state.

3 is a perspective view showing an extract of the G ₆ electrode of the multi-stage focused electron gun for cathode ray tube according to the present invention.

* Explanation of symbols for main parts of the drawings

K: cathode G ₁ : control electrode

G ₂ : screen electrode G ₃ , G ₄ , G ₅ , G ₆ , G ₇ : focus electrode

G ₈ : Anodized electrode Ve: Constant voltage

Vf: Focus Voltage Vd: Dynamic Focus Voltage

Vn: Anode Voltage

The present invention relates to a multi-stage focused electron gun for a cathode ray tube, and more particularly, to improved astigmatism focus characteristics by improving an electrode arrangement structure and a voltage application method thereof.

There are many factors in determining the resolution of the cathode ray tube, but the biggest factor is the size of the beam spot where the electron beam emitted from the electron gun lands on the red, green, and blue phosphors on the screen surface. The size of the beam spokes is commonly referred to as the beam diameter, and when the electron beam is in optimal focus, the smallest spot can be formed, so that the best resolution can be obtained. However, when the electron beam emitted from the electron gun mounted on the neck of the cathode ray tube is deflected by the deflection yoke to the periphery of the screen surface, the trajectory of each optimum focus point forms a parabola with respect to the electron gun enclosed in the neck of the cathode ray tube. do. At this time, the beam spot is distorted into a horizontal ellipse due to the deflection aberration of the deflection yoke and the geometric curvature of the cathode ray tube panel even when the focus is optimally in the center and the peripheral portion of the screen surface. The conventional electron gun for compensating for the distortion of the electron beam spot is shown in Fig. 1 as the cathode (K), the control electrode (G ₁ ), the screen electrode (G ₂ ) and the auxiliary lens system and the main constituting the pre-triode tube portion as shown in FIG. It consists of a focus electrode (G ₃ ~ G ₇ ) and an anode electrode (G ₈ ) constituting a lens system, one of the electrodes G ₇ electrode is formed separately from the G _7a electrode and G _7b . A constant voltage Ve is applied to the screen electrode G ₂ , the G ₄ electrode and the G ₆ electrode, and a focus voltage Vf is applied to the G ₃ electrode, the G ₅ electrode, and the G _7a electrode, which are the focus electrodes. The G _7b electrode is applied with a dynamic focus voltage Vd, which is changed parabolic according to the focus voltage and the vertical synchronization signal period, and also varies according to the horizontal synchronization signal. An anode voltage Vn is applied to the G ₈ electrode, which is the anode electrode.

In the conventional multi-stage focused electron gun, the dynamic focus voltage Vd is applied to the G _7b electrode when the electron beam is emitted from the cathode K and is deflected to the periphery of the screen surface, where the vertical voltage is horizontal. The cross section of the electron beam passing through the main lens system formed between the G _7b electrode and the G ₈ electrode is lengthened by the effect of the quadrupole lens which becomes higher than the voltage in the direction and becomes the elongate shape, thereby correcting astigmatism due to deflection aberration. can do. However, when the cross-sectional phenomenon of the electron beam is changed in the main lens system, the focus characteristic is deteriorated due to the influence of spherical aberration. In addition, when the dynamic focus voltage Vd is applied by dividing the G ₇ electrode into two as described above, the number of electrodes constituting the electron gun increases, which makes the assembly of the electrode difficult and causes the generation of defective products. In particular, since the G ₇ electrode is not long in length (electron gun longitudinal direction), there is a drawback that an effective quadrupole lens cannot be formed when divided into two.

The present invention aims to provide a multi-stage focused electron gun for cathode ray tubes that can easily correct astigmatism and realize optimal focus on the entire screen surface in view of the above problems.

In order to achieve the above object, the present invention includes a cathode, a control electrode, a screen electrode, and an electron beam through-hole, which form an auxiliary triode, and a focus electrode constituting an auxiliary lens system and a main lens system, and an anode electrode. In the electron gun, an electron beam passing hole of the G ₆ electrode is formed in an elongated shape, a constant voltage is applied to the control electrode and the G ₄ electrode, a focus voltage is applied to the G ₃ electrode and the G ₆ electrode, and the G _The dynamic focus voltage is applied to the ₅ electrode and the G ₇ electrode.

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

2 is a cross-sectional view of a cathode ray tube multi-stage focused electron gun according to the present invention, which includes a cathode (K), a control electrode (G ₁ ), a screen electrode (G ₂ ), and a main lens unit and It consists of a focus electrode (G ₃ ~ G ₇ ) and an anode electrode (G ₈ ) constituting the auxiliary lens.

According to a feature of the present invention, a constant voltage Ve is applied to the screen electrode G ₂ electrode and a G ₄ electrode which is the focus electrode, and a focus voltage Vf is applied to the G ₃ electrode and the G ₆ electrode which are the focus electrodes. As shown in the figure, the electron beam passing hole H of the G ₆ electrode is formed in an elongated shape. The dynamic focus voltage Vd, which is varied according to the vertical synchronization signal and the horizontal synchronization signal, is applied to the G ₅ and G ₇ electrodes, which are the focus electrodes, and the anode voltage Vn is applied to the G ₈ electrode, which is the anode electrode.

The multi-stage focused electron gun for a cathode ray tube configured as described above has a prefocus fence formed by the G ₂ electrode which is the screen electrode and the G ₃ electrode which is the focus electrode, and the G ₃ electrode, the G ₄ electrode, the G ₅ electrode, and the G ₅ electrode which are the focus electrodes. Uni-potential type first and second auxiliary lenses are formed by the electrode, the G ₆ electrode, and the G ₇ electrode, respectively. The bi-potential is formed by the G ₇ electrode and the G ₈ electrode, which is an anode wood electrode. ) The main lens is formed. Accordingly, when the electron beam emitted from the cathode K is scanned to the center of the screen surface, the dynamic focus voltage Vd is not applied to the G ₅ and G ₇ electrodes, which form the second auxiliary lens. The voltage applied to the G ₅ electrode, the G ₆ electrode, and the G ₇ electrode, that is, the potential difference is the same, so that the electrostatic lens is not formed. Accordingly, the electron beam emitted from the cathode K is preliminarily diverged, focused, and accelerated in the prefocus lens and the first auxiliary lens, and finally connected and accelerated in the main lens to be landed in an optimal focus state in the center of the screen surface. .

When the electron beam emitted from the cathode K is deflected by the deflection yoke to the periphery of the screen, the G ₅ and G ₇ electrodes are parabolic according to a vertical synchronization signal and a horizontal synchronization signal. When the variable dynamic focus voltage Vd is applied, an electrostatic lens is formed. In this case, since the G ₆ electrode has an electron beam through hole H, the electric field distribution of the electrostatic lens is weakly formed on the horizontal side. Strongly formed on the vertical side. Therefore, the focusing force on the vertical side is weaker than the focusing force on the horizontal side, so that the cross section of the electron beam passing through the second auxiliary lens has an elongated elliptical shape. As such, the longitudinal electron beam passes through the main lens and is finally focused and accelerated, and then deflected by the deflection yoke to the periphery of the screen. A circular beam spot can be obtained at the periphery of the screen surface by correcting the long spreading distortion.

As described above, the multi-stage focused electron gun for the cathode ray tube is used to correct the deflection aberration and astigmatism caused by the non-uniform magnetic field of the deflection yoke by changing the electric field distribution of the horizontal vertical constituting the auxiliary lens in synchronization with the deflection signal applied to the deflection yoke. In addition, it is possible to form a beam spot having a substantially uniform size on the entire screen surface, and to obtain an optimal focus characteristic, and furthermore, to produce a color cathode ray tube capable of realizing a clear image.

Claims (1)

Pre-triode portion for forming the cathode, a control electrode and a screen electrode and the electron beam G ₃ to G ₇ of the focus electrode, and a cathode-ray tubes multistage focusing type electron gun with by having the anode electrode pass by having a hole forming the auxiliary lens system and juren perimeters The electron beam passing hole H of the G ₆ electrode is formed in an elongated shape. A constant voltage Ve is applied to the control electrode and the G ₄ electrode, a focus voltage Vf is applied to the G ₃ electrode and the G ₆ electrode, and a dynamic focus voltage Vd is applied to the G ₅ electrode and the G ₇ electrode. A multistage focused electron gun for cathode ray tubes, characterized in that it is applied.