KR20030071369A - An Electric Gun For The Cathode-ray Tube - Google Patents

Abstract

PURPOSE: An electron gun of a CRT(Cathode Ray Tube) is provided to be capable of improving focus characteristics and resolution by adequately controlling the vertical and horizontal size of electron beam passing holes of the first and second electrode. CONSTITUTION: An electron gun of a CRT includes a triode part, wherein the triode part has a cathode for emitting electron beam to a fluorescent screen, the first electrode spaced apart from the cathode for controlling the electron beam, and the second electrode spaced apart from the first electrode for accelerating the electron beam. When expressing the horizontal width of electron beam passing holes formed at the first electrode as 'H1', the vertical width of the electron beam passing holes formed at the first electrode as 'V1', and the rate between the horizontal and vertical width as 'P1(=H1/V1), the relational expression of '1.1< P1< 1.38' is satisfied. The thickness of the peripheral portion of the second electrode is homogeneous.

Description

Electron Gun for Cathode Ray Tube {An Electric Gun For The Cathode-ray Tube}

The present invention relates to an electron gun for cathode ray tube, and more particularly, to an electron gun for cathode ray tube that improves focus characteristics and resolution by reducing the vertical spot size of the battery beam by adjusting the size of electron beam through holes of the first electrode and the second electrode.

As shown in FIG. 1, the conventional flat color cathode ray tube structure includes a front glass called panel 1 and a rear glass called funnel 2, and a fluorescent surface having a predetermined light emission therein, and the fluorescent surface. An electron gun 8 emitting an electron beam 11 emitting light, a shadow mask 3 serving as color screening, a frame 4 for welding and fixing the shadow mask, a stud pin 6 and a spring 5; It consists of. In addition, the inner shield 7 which serves to shield the cathode ray tube so as to be less affected by external geomagnetism during operation is fixed to the frame 4 and is sealed with high vacuum.

The general principle of cathode ray tube operation is as follows. In the electron gun 8 embedded in the neck of the funnel 2, the electron beam 11 strikes the fluorescent surface formed on the inner surface of the panel 1 by the anode voltage applied to the cathode ray tube, and the electron beam reaches the fluorescent surface. Before the deflection yoke (9) is deflected up, down, left and right to form a screen. And there is a magnet to correct the trajectory so that the electron beam hits the phosphor accurately, thereby preventing poor color purity. In addition, since the cathode ray tube is made of high vacuum, it may be easily deflated due to external impact. In order to prevent this, the reinforcing band 10 is mounted on the skirt portion of the panel to distribute the stress of the cathode ray tube in a high vacuum state, thereby improving impact resistance. Secure.

Referring to the configuration of the electron gun in detail through the drawings, as shown in Fig. 2, the cathode 12 for generating an electron beam, the first electrode 13 is disposed by a predetermined distance from the cathode, arranged at a predetermined interval from the first electrode And a triode consisting of a second electrode 14 for accelerating the electron beam, a third electrode 15, a fourth electrode 16, a focusing electrode 17, 18 disposed at a predetermined distance from the second electrode, and It is composed of a positive electrode 19, a shield cup 20 for attaching to the end of the positive electrode to shield the leakage magnetic field and a BSC 28 for supporting the electron gun. The electrodes are fixed by the bead glass 23 while maintaining a constant interval, the electron gun is inserted into the neck glass 26 constituting the neck portion of the funnel (2) and the neck glass from the outside to the voltage to the electron gun It is fused with a portion of the stem 25 to be applied and mounted on the cathode ray tube.

Referring to the operation of the electron gun, the heater 22 embedded in the cathode 12 receives the voltage applied to the stem pin 27 to emit electrons, and the emitted electrons are the first electrode 13 which is a control electrode. The electron beam is controlled by the second electrode 14, which is an acceleration electrode, and the UPF lens is formed between the third electrode 15, the fourth electrode 16, and the focusing electrode 17. The electron beam is partially focused, and the electron beam is mainly connected and accelerated by the focusing electrode 18 and the anode 19, and passes through the shadow mask 3 provided on the inner surface of the fluorescent surface to collide with the fluorescent surface to generate light. In addition, the electron beam 11 emitted from the electron gun is deflected to the entire screen by the deflection yoke 9 mounted to the outside of the electron gun, thereby realizing a screen.

The shape and dimensions of the first electrode 13 and the second electrode 14 are important factors in determining the shape and size of the electron beam spot constituting the screen of the cathode ray tube. In particular, the first electrode is a prefocus lens. It determines the bright spot erasing voltage and current density, which has the greatest influence on the shape of the initial electron beam.

In general, when the size of the electron beam through hole of the first electrode and the second electrode is reduced, the size of the object point is reduced, and thus the size is reduced without decreasing the divergence angle when the electron beam is incident on the main lens, and thus the electron beam spot size on the screen. Is reduced. However, the reduction of the electron beam passing holes of the first electrode and the second electrode has a lot of difficulties because it may cause a negative effect due to the repulsive force between electrons in the electron gun for CPT requiring high brightness.

In order to overcome the above problem, conventionally, the circular electron beam through-holes are formed in a quadrangle by reducing the horizontal and vertical dimensions of the electron beam through-holes while maintaining the repulsive force between the electrons. That is, the area of the circular through-hole having a diameter of 0.5 mm is 0.25 × 0.25 × π ≒ 0.196mm2. The area of the square having 0.45mm of horizontal and vertical width is 0.45 × 0.45 ≒ 0.203mm2. The area that can trigger the repulsion of the liver is rather enlarged. Therefore, as described above, when the electron beam passing hole is formed in a quadrangle, the electron beam spot can be reduced to improve the resolution.

Also, as another method of reducing the electron beam spot and improving the resolution, the speed modulating coil 30 is mounted on the net of the cathode ray tube in which the electron gun is installed, which is emitted by the image signal and deflected by the deflection yoke. When the screen is configured on the screen, the magnetic field of the speed modulating coil, which is synchronized with the video signal, modulates the deflection speed at the beginning and the end of the video signal, thereby reducing the horizontal size of the electron beam spot by 15 to 30%.

Also, conventionally, to reduce the vertical size of the electron beam spot, the electron beam passing hole of the first electrode is transversely shaped to reduce the repulsive force between electrons that affect the size of the electron beam spot on the screen of the cathode ray tube equipped with a high-brightness CPT electron gun. It was formed into a long rectangle. That is, since the horizontal width is larger than the vertical width, not only the asymmetrical lenses in the vertical and horizontal directions that determine the shape of the electron beam are formed asymmetrically, but also the virtual crossover of the electron beam in the horizontal and vertical directions is different. The repulsive force between the electrons can be significantly reduced. At this time, the size of the horizontal direction of the electron beam spot is enlarged by the transverse rectangular electron beam passing hole, but this can be compensated by the mounting of the speed modulating coil described above.

The above-mentioned method of reducing the electron beam spot was intended to reduce the electron beam size by reducing the physical electron beam passing hole. However, in the case of the actual CPT electron gun, the current is increased to increase the luminance, and thus the repulsive force between the electrons becomes stronger, thereby causing the electron beam. It is not possible to adjust the divergence angle of the electron beam, but rather, the shape of the electron beam is changed, and as the electron beam passing hole is reduced, the bright spot erasing voltage is lowered, which lowers the drive characteristics of the electron beam, thereby causing problems in increasing the current density and luminance. The focus characteristic is rather deteriorated. In addition, workability is poor during span-set work due to the reduction of electron beam through holes.

Accordingly, the present invention is to solve the above problems, in particular by adjusting the vertical and horizontal size of the electron beam through hole of the first electrode and the second electrode appropriately to reduce the vertical spot size of the battery beam to improve the focus characteristics and resolution An object of the present invention is to provide an electron gun for a cathode ray tube.

1 is a structural diagram of a typical color cathode ray tube

2 is a structural diagram of a typical cathode ray tube electron gun

3 is a view illustrating a magnet and a speed modulating coil mounted on a neck part;

4a to 4b are views showing the shape of the electron beam through hole of the electrode according to the present invention.

5A is a view illustrating a change in the size of an electron beam spot according to the vertical width of the first electrode electron beam through hole;

5B is a view showing the size of the electron beam spot according to the horizontal width of the first electrode electron beam through hole;

5C is a diagram illustrating a relationship between an area of a first electrode electron beam through hole and a cut-off voltage.

6 is a view showing a change in the size of the electron beam spot according to the width of the second electrode electron beam through hole

7 is a view showing a change in the size of an electron beam spot according to the electrode thickness around the second electrode electron beam through hole;

*** Explanation of symbols for the main parts of the drawing ***

8: electron gun 9: deflection yoke

13: first electrode 14: second electrode

30: speed modulating coil

The technical means of the present invention for achieving this object is a cathode for emitting an electron beam toward the phosphor screen, a first electrode disposed at a predetermined distance from the cathode to control the electron beam, and arranged at a predetermined interval from the first electrode In the electron gun for a cathode ray tube including a three-pole portion consisting of a second electrode for accelerating the electron beam, the horizontal width of the electron beam through hole formed in the first electrode is H1, the vertical width V1, the ratio of the horizontal width and the vertical width P1 ( = H1 / V1), 1.1 &lt; P1 &lt; 1.38, and the electrode thickness around the electron beam through hole formed in the second electrode is uniform.

When the horizontal width of the electron beam through hole formed in the second electrode is H2, the vertical width is V2, the ratio of the horizontal width to the vertical width is P2 (= H2 / V2), and the electrode thickness around the electron beam through hole is T2. It is characterized by satisfying the following equations.

0.5 × ｛(H2 + V2) / 2｝ <T2 <0.85 × ｛(H2 + V2) / 2｝

0.7 <P2 <1.3

Preferably, V1 &lt; 0.512 mm.

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

4A and 4B illustrate the shapes of electron beam through holes of the first electrode and the second electrode according to the present invention. In order to determine a desirable ratio between the horizontal width H1 and the vertical width V1 of the electron beam passing hole, while changing one of the horizontal width and the vertical width, the size of the electron beam spot that appears on the screen is changed. Was confirmed through a simulation, and the results are shown in FIGS. 5A and 5B. At this time, it is assumed that the shape of the electron beam through hole of the second electrode is the same in the horizontal and vertical widths.

5A and 5B, when the ratio of the horizontal width to the vertical width of the electron beam through hole of the first electrode (P1 = H1 / V1) is 1.12 to 1.14, the shape of the electron beam spot displayed on the screen is circular. It could be known. In addition, when P1 is lower than the above range, the spot has an elongate shape, that is, a vertical size is larger than a horizontal size. On the other hand, when P1 becomes large, the shape of the spot becomes horizontal, that is, the horizontal size is larger than the vertical size. However, even when P1 is 1.23 or more, horizontal spot reduction can be achieved by installing the above-described speed modulating coil.

In addition, even if P1 satisfies the above range, if the absolute dimension of the electron beam through hole is reduced, the repulsive force between electrons becomes stronger due to the reduction of the area of the through hole as mentioned in the problems of the prior art, and thus it is not possible to control the divergence angle of the electron beam. As the erase voltage is lowered, there is a problem that the characteristics of the electron beam drive are drastically lowered.

Therefore, in designing the electron beam through hole of the first electrode, the area of the electron beam through hole should be considered along with the ratio of the horizontal width to the vertical width, and the electron beam through hole area (B1 = H1 × V1) and cut-off. The relationship with the voltage is shown in Fig. 5C. Since the cutoff voltage of a CPT electron gun has a value of 60 to 90 V, the area of the electron beam through hole must be in the range of 0.158 to 0.25 mm 2 to satisfy this.

When the area of the through hole is 0.25 mm 2 or more, the cutoff voltage exceeds 90 V. In this case, the distance between the cathode and the first electrode needs to be increased, which makes it difficult to set conditions for the activation process of the cathode, and Disadvantages.

In the above, the electron beam through hole of the first electrode has been described. However, in order to have the above effects, the shape and dimensions of the second electrode must also be appropriately adjusted. As described above, the simple reduction of the size of the second electrode causes a repulsion effect between the electrons, and thus the vertical and horizontal widths of the second electrode and the thickness of the electrode around the electron beam through hole according to the vertical and horizontal widths of the first electrode. Must be defined.

On the other hand, the spot size of the electron beam through hole in the screen according to the horizontal width and the vertical width of the second electrode is as shown in FIG. Therefore, in consideration of the interelectron repulsion effect, the horizontal width H2 of the electron beam through hole of the second electrode is not less than 0.45 mm, and the ratio of the horizontal width H2 and the vertical width V2 (P2 = H2 / V2) is 0.9. The ratio P1 of the horizontal width to the vertical width of the electron beam through hole of the first electrode is in the range of 1.1 to 1.67, and the horizontal width H1 is the horizontal of the second electrode electron beam through hole. It shall not exceed 1.4 times the width (H2).

When the horizontal width H1 of the electron beam through hole of the first electrode is equal to or greater than 1.4 times the horizontal width H2 of the electron beam through hole of the second electrode, the bright point erase voltage of the electron gun is increased, and when the bright point erase voltage is lowered, the first electrode Since the distance between the cathode and the cathode is too far, not only the productivity of the process is disadvantageous, but also the incident area to the main lens is widened due to the sudden increase in the divergence angle in the horizontal direction, thereby reducing the electron beam spot appearing on the screen.

On the other hand, the electrode thickness around the electron beam through hole of the second electrode is closely related to the size of the water point. In particular, in the electron gun in which the electron beam through hole of the first electrode has a shape where the horizontal width is larger than the vertical width, the electron beam passes through the second electrode. The same electrode thickness around the ball reduces the size of the object in the vertical direction, thereby reducing the size of the vertical spot on the screen. As described above, the vertical reduction of the electron beam spot by reducing the vertical width of the electron beam through hole of the first electrode lowers the cut-off voltage. In this case, as described above, the electron beam through hole around the second electrode is reduced. When the electrode thickness is uniformly applied, the distance between the first electrode and the second electrode can be secured by about 10 to 20 μm, thereby overcoming the limitation caused by the cut-off voltage. .

When the thickness of the electrode around the electron beam through hole of the second electrode is uniform, the size of the electron beam spot on the screen according to the thickness t of the electrode is shown in FIG. 7. In other words, when the thickness of the second electrode is 50 to 85% of the diameter of the electron beam passing hole, the size of the water spot is effectively reduced so that the vertical size of the electron beam spot on the screen is effectively reduced.

In summary, the horizontal width of the first electrode is H1, the vertical width is V1, the ratio of the horizontal width to the vertical width is P1 (= H1 / V1), and the area is B1 (= H1 x V1). When the horizontal width of the second electrode is H2, the vertical width is V2, the ratio of the horizontal width to the vertical width is P2 (= H2 / V2), and the thickness is T2, the following equations are satisfied.

1.1 <P1 <1.38

0.7 <P2 <1.3

0.5 × ｛(H2 + V2) / 2｝ <T2 <0.85 × ｛(H2 + V2) / 2｝

As described above, the present invention can reduce the vertical size of the electron beam spot on the screen by adjusting the vertical and horizontal widths of the electron beam passing holes of the first electrode and the second electrode, thereby improving the resolution and reducing the bright spot erase voltage. It is possible to secure enough electron beam drive characteristics, thereby increasing current density and brightness, thereby improving focus characteristics.

Claims (4)

A triode comprising a cathode for emitting an electron beam toward the phosphor screen, a first electrode disposed at a predetermined distance from the cathode to control the electron beam, and a second electrode disposed at a predetermined interval from the first electrode to accelerate the electron beam In the electron beam for cathode ray tube containing, 1.1 <P1 <1.38 when the horizontal width of the electron beam through hole formed in the first electrode is H1, the vertical width is V1, and the ratio of the horizontal width to the vertical width is P1 (= H1 / V1); The electron gun for a cathode ray tube, characterized in that the electrode thickness around the electron beam through hole formed in the second electrode is uniform. The method of claim 1, An electron gun for a cathode ray tube, wherein the horizontal width of the electron beam through hole formed in the second electrode is H2, the vertical width is V2, and the electrode thickness around the electron beam through hole is T2. 0.5 × ｛(H2 + V2) / 2｝ <T2 <0.85 × ｛(H2 + V2) / 2｝ The method of claim 1, An electron gun for cathode ray tubes, wherein V1 <0.512 mm. The method of claim 1, When the horizontal length of the electron beam through hole of the second electrode is H2, the vertical length is V2, and the ratio of the horizontal width and the vertical width is P2 (= H2 / V2), 0.7 <P2 <1.3, the electron gun for cathode ray tube .