KR20010002780A - Electric gun of the CRT - Google Patents

Abstract

PURPOSE: An electron gun for a cathode ray tube is provided to form the different static lens to respective electron beam when beam is deflected into the peripheral part of the screen without adding voltage, and allow all electron beam to be forward-focused into the horizontal and perpendicular directions in the whole screen. CONSTITUTION: An electron gun for a cathode ray tube consists of a plurality of electrodes, a triode part and free focus lens parts(25,26). In the electron gun for a cathode ray tube, a differential circuit(300) differentiates a dynamic voltage synchronized with the deflection current amount of a deflection york.. A primary lens part includes the first focusing electrode(27-1) applied with a direct current having a described potential, the second focusing electrode(27-2) applied with the wave form of the dynamic voltage differentiated in the differential circuit and the third focusing electrode(27-3) applied with the dynamic voltage.

Description

Electron gun for cathode ray tube {Electric gun of the CRT}

The present invention relates to an electron gun, and more particularly, to an electron gun for a cathode ray tube which allows all electron beams to be positively focused in the horizontal and vertical directions at the periphery of the screen.

Hereinafter, an electron gun for a cathode ray tube according to the prior art will be described with reference to the accompanying drawings.

1 is a cross-sectional view showing a schematic configuration of a general color water pipe, Figure 2 is a view showing a general internal structure of the electron gun shown in Figure 1, Figure 3 is a first and second focusing electrode shown in FIG. It is a figure which shows the waveform of the applied voltage.

As shown in FIG. 1, a general color water pipe is composed of a cathode ray tube and a deflection yoke 12. The cathode ray tube has a fluorescent surface (not shown) and a color screening function coated with red, green, and blue phosphors on the front inner surface. The shadow mask 16 having the shadow mask 16 is coupled to the screen 17 to which the shadow mask 16 is connected, and is formed of a funnel having a tubular neck portion formed rearward.

An electron gun is embedded in the funnel neck portion, and a deflection yoke 12 is coupled to the outside to deflect the electron beams 13, 14, 15 emitted from the electron gun in a horizontal or vertical direction. Step 1 is coupled to the end of the electron gun to apply a voltage to each electrode of the electron gun.

As shown in FIG. 2, the electron gun includes a cathode 3 for emitting an electron beam, an acceleration electrode 5 for accelerating hot electrons of the cathode 3, and a pre-focus electrode 6 for focusing the electron beams. 7), first and second focusing electrodes 8-1 and 8-2 for focusing the focused electron beams in one direction, and an anode 9 for applying a high voltage to the focused electron beams. do.

In particular, the focusing electrode is divided into a first focusing electrode 8-1 and a second focusing electrode 8-2, and a horizontal partition wall is provided on the cathode direction electrode surface of the second focusing electrode 8-2.

The ball of the direction of the anode 9 of the first focusing electrode 8-1 has a rim common to the three electron beams and has a plate having three balls therein, and the second focusing electrode 8-2 The horizontal partition wall 30 is inserted into the rim 29 of the first focusing electrode 8-1.

In the electron gun as described above, the heater 2 embedded in the cathode 3 heats the cathode, and thermal electrons are emitted, and the thermal electrons are electron beams 13, 14, 15 by the control electrode 4, which is a control electrode. ) Is controlled, and the electron beams 13, 14, 15 are accelerated by the accelerating electrode 5, and pass through the second focusing electrode 8-2 and the anode 9, which are the main lens forming electrodes, to the screen ( 17) It passes through the shadow mask 16 provided on the inner surface and collides with the fluorescent surface 17 to emit light.

The deflection yoke 12 deflects the electron beams 13, 14, 15 emitted from the electron gun outside the electron gun to the entire screen 17.

A quadrupole lens is formed between the first focusing electrode 8-1 and the second focusing electrode 8-2, and the lens is applied to the dynamic voltage 21 synchronized by the deflection current as shown in FIG. By the strength thereof.

As shown in FIG. 3, the quadrupole lens formed between the first focusing electrode 8-1 and the second focusing electrode 8-2 has the greatest deflection force of the deflection yoke 12. The corner portion (b) and the quadrupole lens function at the time of deflection and the smallest quadrupole lens function at the center portion (a) of the screen without deflection force.

Inline electron guns without conventional quadrupole lenses cause horizontal spot diameter enlargement at the periphery of the screen due to non-uniform magnetic field of the salve convergence deflection yoke and hollow phenomenon due to vertical spot diameter and focusing. Bring.

This phenomenon refers to the phenomenon of weakening the horizontal (inline) electron beam focusing force by the deflection non-uniform magnetic field and enhancing the electron beam focusing power of the vertical direction (direction perpendicular to the inline direction).

However, the electron gun for the cathode ray tube according to the prior art has the following problems.

First, since the voltage necessary for focusing the electron beam on the peripheral part of the screen does not match, a hollow phenomenon and a blooming phenomenon occur.

Second, the focus quality is reduced by the hollow phenomenon and the blooming phenomenon.

Third, since the connection of the electron beam is unbalanced by the hollow phenomenon and the blooming phenomenon, deterioration of focus is caused.

The present invention has been made to solve such a problem, and when the beam is deflected to the periphery of the screen without adding a separate voltage to form a different electrostatic lens on each electron beam, all the electron beam in the horizontal, vertical direction Its purpose is to provide an electron gun for cathode ray tubes that can be focused in the right direction.

1 is a view showing a typical TV CRT

2 is a view showing a part of the electron gun for the cathode ray tube according to the prior art

3 is a view illustrating voltage waveforms applied to first and second focusing electrodes illustrated in FIG.

4 is a view showing an electron gun for a cathode ray tube according to the present invention;

5 is a circuit diagram showing in detail the differential circuit shown in FIG.

FIG. 6 is a diagram illustrating voltage waveforms applied to first to third focusing electrodes illustrated in FIG. 4.

7a to 7c show an embodiment according to the invention.

Explanation of symbols for main parts of the drawings

21 heater 22 cathode

23: control electrode 24: acceleration electrode

25, 26: pre-focus electrode 27-1: first focusing electrode

27-2: second focusing electrode 27-3: third focusing electrode

28: anode 29: shield cup

31-1: First voltage section 31-2: Second voltage section

33: R beam 34: G beam

35: B beam 36-1: first burring portion

36-2: second burring portion 37: dynamic electrode portion

300: differential circuit

Cathode ray tube electron gun according to the present invention for achieving the above object is a triode consisting of a plurality of cathodes for emitting an electron beam, and at least two or more electrodes for controlling the amount of electron beam emitted from the cathode and accelerate the electron beam to the screen side And a prefocus lens unit comprising a prefocus lens section comprising at least two electrodes for focusing a predetermined amount of electron beams accelerated by the tripolar section, comprising: a differential circuit for differentiating a dynamic voltage synchronized by a deflection yoke deflection current amount; And a first focusing electrode receiving a DC voltage having a constant potential lower than an anode, a second focusing electrode receiving a waveform of a dynamic voltage differentiated in the differential circuit, and a third focusing electrode receiving the dynamic voltage. It is configured to include a lens unit has its features.

Hereinafter, an electron gun for a cathode ray tube according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 4 is a view showing an electron gun for a cathode ray tube according to the present invention, FIG. 5 is a circuit diagram showing the differential circuit shown in FIG. 4 in detail, and FIG. 6 is a voltage applied to the first to third focusing electrodes shown in FIG. A diagram showing a dynamic waveform diagram of the diagram.

As shown in FIG. 4, the cathode 22 is for emitting electron beams, and the control electrode 23 controls the electron beams emitted from the cathode 22.

Acceleration electrode 24 accelerates the hot electrons of the cathode 22 and pre-focus electrodes 25 and 26 focus the electron beams.

The first to third focusing electrodes 27-1, 27-2, and 27-3 focus electron beams focused by the pre-focus electrodes 25 and 26 in one direction, and the anode 28 is A high voltage is applied to the electron beams focused on the first to third focusing electrodes 27-1, 27-2, and 27-3.

The first burring portion 36-1 is formed between the first focusing electrode 27-1 and the second focusing electrode 27-2 at different heights between the three beams in a beam path direction.

At this time, the depth of the burring formed on the first focusing electrode 27-1 satisfies the condition of R beam <G beam <B beam, and the depth of the burring formed on the second focusing electrode 27-2 is R The condition of beam> G beam> B beam is satisfied.

That is, in the first focusing electrode 27-1, the burring depth is the deepest in the B beam, the deepest in the G beam, and the shallowest in the R beam, and the second focusing electrode 27-2. ) Has the opposite structure.

In addition, the second burring portion 36-2 is formed to increase the parasitic capacitance component between the second focusing electrode 27-2 and the third focusing electrode 27-3, and the dynamic electrode portion 37 Condenses the electron beam output through the second burring portion 36-2 by the dynamic electrode applied to the third focusing electrode 27-3.

The differential circuit 300 adjusts the voltage applied to the second focusing electrode 27-2.

As shown in FIG. 5, the differential circuit 300 includes a first voltage unit 31-1 for applying a static voltage to the first focusing electrode 27-1, and the first focusing electrode 27. A resistor (R) connected in series between the second focusing electrode (27-1) and the second focusing electrode (27-2) to form a closed circuit, and connected to the resistor (R) in series with the second focusing electrode (27-2). A capacitor (C) representing the parasitic capacitance component between the third focusing electrodes (27-3) and a capacitor (C) connected in series to apply a dynamic voltage (Vi) to the third focusing electrode (27-3). It consists of the 2nd voltage part 31-2.

In this case, the magnitude of the voltage across the resistor R is Vc, and the dynamic voltage applied to the third focusing electrode 27-3 is Vi, and if Vi = Acosωt, the voltage across the resistor R is assumed. The applied voltage Vo is calculated by the following equation.

Here, it is assumed that Vi = Acosωt, and A means the amplitude of the dynamic waveform.

Therefore, if the product of the magnitude R of the resistance and the magnitude C of the parasitic capacitance component is sufficiently smaller than the period 1 / ω of the dynamic waveform, a differential voltage waveform as shown in Fig. 6 can be obtained. At this time, the amplitude of the differential voltage waveform As determined by, the magnitude of the voltage waveform applied to the second focusing electrode 27-2 may be controlled according to the selected R value.

When the potential of the second focusing electrode 27-2 is deflected to the left of the screen of the beam by the differential voltage waveform, the potential of the first focusing electrode 27-1 is lower than that of the first focusing electrode 27-1 (c), and the beam is moved to the right of the screen. When deflected, it becomes higher than the potential of the first focusing electrode 27-1 to form a weak electrostatic focusing lens between the first focusing electrode 27-1 and the second focusing electrode 27-2.

Here, when the beam is deflected to the left side of the screen as described above, the electrostatic focusing lens formed on the R-beam side is lower than the electrostatic focusing lens on the B and G beams due to the burring depth of the second focusing electrode 27-2 having a low electric potential. Under strong focusing action

On the other hand, when the beam is deflected to the right side of the screen as described above, the electrostatic lens on the B-beam side is stronger than the electrostatic focusing lens on the R and G beam side by the deep burring depth of the first focusing electrode 27-1 having a low potential. Under focus.

Therefore, it can be seen that when the beam is deflected, the inner beam receives a stronger electrostatic focusing lens effect than the center beam and the outer beam, and the outer beam receives the weakest electrostatic focusing lens effect.

Referring to FIGS. 7A to 7C, an electro-optical model formed by such an operation is as follows.

FIG. 7A is a view showing a lens formed in an outer beam in which an overfocused quadrupole generated by a deflection yoke (not shown) is formed by forming a relatively weak electrostatic focusing lens 38 in the outer beam when the beam is deflected. The lens effect 40 is canceled to improve the focus h and f in the horizontal and vertical directions.

7C is a view showing a lens formed in the inner beam, and a relatively strong electrostatic focusing lens 44 is formed in the inner beam to thereby provide the unfocused quadrupole lens effect 46 generated by the deflection yoke (not shown). It cancels and improves the focus k (m) of a horizontal and a vertical direction.

Cathode ray tube electron gun according to the present invention has the following effects.

First, since the burring depths of the first focusing electrode and the second focusing electrode are formed differently according to the respective beams, electrostatic focusing can be selectively performed according to the deflection direction, thereby minimizing the deterioration of focus.

Second, by applying the dynamic voltage to the second focusing electrode as a differential voltage waveform, it is possible to improve the focus quality in the entire area of the screen when the electron beam is deflected.

Third, as the quality of the focus is improved, the larger the size of the cathode ray tube and the larger the deflection angle, the more the required high resolution can be satisfied.

Claims (5)

A triode consisting of a plurality of cathodes emitting electron beams, at least two electrodes for controlling the amount of electron beams emitted from the cathode and accelerating the electron beams to the screen side, and at least a predetermined amount of focusing the electron beams accelerated by the tripoles In the electron beam gun for a cathode ray tube provided with a prefocus lens portion consisting of two or more electrodes, A differential circuit for differentiating a dynamic voltage synchronized with the amount of deflection current of the deflection yoke; The main lens unit includes a first focusing electrode receiving a DC voltage having a constant potential, a second focusing electrode receiving a waveform of a dynamic voltage differentiated in the differential circuit, and a third focusing electrode receiving the dynamic voltage. Electron gun for cathode ray tube, characterized in that configured. The method of claim 1, An electron gun for a cathode ray tube, wherein a first burring portion having a different height is formed between the first focusing electrode and the second focusing electrode between beams. The method of claim 1, And a second burring portion facing the vertical direction of the electron beam path is formed on a third focusing electrode to which the dynamic voltage is applied. The method of claim 3, wherein Electron gun for cathode ray tube, characterized in that the second burring portion is a rectangular plate shape. The method of claim 1, An electron gun for a cathode ray tube, characterized in that a resistor is connected in series between the first focusing electrode and the second focusing electrode to form a closed circuit.