KR100339372B1 - electron gun for cathode ray tube - Google Patents

Abstract

The present invention relates to an electron gun for a cathode ray tube, and an object of the present invention is to provide an electron gun for a cathode ray tube that can improve the overshoot characteristics of the cathode current by minimizing the thermal deformation of the first electrode as a control electrode to bring a faster stabilization. .

Furthermore, another object of the present invention is to provide an electron gun for a cathode ray tube which is easy to manufacture a monitor or a TV chassis and is inexpensive by preventing the cutoff voltage from being lowered even if the thickness around the electron beam through hole of the ultra-high resolution electron gun becomes thin.

In order to achieve the above object, the cathode ray tube electron gun according to the present invention is formed of a plurality of cathodes for emitting the electron beam by the heating of the heater and the first electrode having an electron beam through hole formed perpendicular to the path of the electron beam and the electron beam In the electron gun for a cathode ray tube including a three-pole portion consisting of a second electrode for acceleration, the through-hole forming portion for forming the electron beam through hole of the first electrode is inclined toward the cathode, the through hole of the first electrode The forming portion is inclined such that the electron beam passing hole retracts 25 to 45 µm in the cathode direction, and in particular, the passing hole forming portion of the first electrode is inclined so as to retreat 35 µm in the cathode direction.

Description

Electron gun for cathode ray tube

TECHNICAL FIELD The present invention relates to a cathode ray tube, and more particularly, to an electron gun for a cathode ray tube that irradiates an electron beam of three colors R, G, and B.

In general, a cathode ray tube is a device that substantially realizes an image in an image display device. The general structure thereof will be described below with reference to the accompanying drawings.

1 is a cross-sectional view showing a structure of a general cathode ray tube, a panel 1 having a fluorescent surface coated with R, G, and B fluorescent materials on its inner side, and a funnel fused using frit glass on the rear of the panel. (2) forms an outer skeleton. In the neck portion of the funnel 2, an electron gun 10 for irradiating electron beams 19 of three colors R, G, and B is enclosed.

In addition, the rear inner surface of the panel 1 includes a shadow mask 3 including a plurality of slits for selecting the color of the electron beam, and a frame assembly (not shown) for supporting the shadow mask.

The funnel 2 includes a deflection yoke 5 for deflecting the electron beam 19 up and down, left and right, and a correction magnet for preventing color purity defects by correcting the traveling trajectory so that the electron beam 19 strikes the phosphor precisely. (Not shown) is provided.

The detailed structure of the electron gun 10 will be described with reference to FIG. 2.

FIG. 2 is an enlarged cross-sectional view illustrating an enlarged structure of an electron gun for a general cathode ray tube, and schematically illustrates a state of a cathode and respective electrodes according to heater heating of the electron gun, and an arrow indicates an expansion direction according to heater heating.

The electron gun 10 is a heater 11 for generating heat by receiving power, a cathode support 13 for supporting three independent cathodes 12 on the front surface of the heater, and a constant on the front surface of the cathode 12. The first electrode 14, which is spaced apart from each other, serves as a common grid of the three cathodes 12, and the second electrode 15 sequentially spaced apart from the first electrode at a predetermined interval.

The electrodes 14 and 15 are formed at regular intervals from each other so as to be perpendicular to the traveling path of the electron beam so that the electron beam irradiated from the cathode 12 is controlled at a constant intensity to reach the screen. . In particular, the electron beam through hole 14h of the first electrode 14 is formed to be completely perpendicular to the path of travel of the electron beam.

At this time, the first electrode 14 is called a control electrode because it controls the electron beam irradiated from the cathode 12, the second electrode 15 serves to accelerate by pulling the hot electrons gathered on the cathode surface. Therefore, it is called an acceleration electrode. The cathode 12, the first electrode 14, and the second electrode 15 are collectively called a tripolar portion.

In addition to the tripolar portion, a plurality of electrodes are provided, but a description thereof is omitted here, and the operation of the tripolar portion will be described in detail as follows.

First, when a predetermined voltage (6.3V) is applied to the heater 11, the heater 11 and the cathode 12 is heated to 720 ~ 800 ° C by the heater resistance so that the cathode 12 is the first electrode 15 90 ~ 100㎛ expanded to the side. In addition, the cathode support 13 supporting the cathode 12 receives heat from the cathode and expands about 20 to 35 μm in a direction opposite to the first electrode 14. Subsequently, the first electrode 14 expands by about 50 to 60 μm toward the second electrode 15, and finally, the second electrode 15 having the lowest heat transfer of the cathode 12 is the first electrode ( 14) expands to the side. At this time, each of these expansions changes the cathode current, which affects the background characteristics.

3 is a graph showing a current change amount according to a heater heating of a conventional electron gun for cathode ray tube, the horizontal axis represents time and the vertical axis represents the current change amount.

As shown in FIG. 3, while the heater is applied with power and generates heat, the cathode expands first to show a current change amount, and then the current change amount is shown in the order of the cathode support, the first electrode, and the second electrode. When the magnitudes of the current change amounts are arranged in order, it can be seen that the cathodes, the first electrode, the second electrode, and the cathode support are arranged in order. At this time, the combination of the current characteristics of each of the elements is called an over shoot characteristic, which is an important factor in determining the settling time.

4 is a graph showing the overshoot characteristics of the conventional electron gun for cathode ray tube, the horizontal axis represents time and the vertical axis represents the amount of current combining the amount of current change of each element of FIG.

As shown in FIG. 4, first, the cathode receives heat from the heater and thermally expands to the first electrode side, and the current rapidly increases along the curve along the A section. Next, while the negative electrode support receives heat from the negative electrode and thermally expands in the opposite direction to the negative electrode, the current decreases along the curve of section B. Subsequently, the first electrode expands to the second electrode side with the heat conduction of the cathode, thereby reducing the current like the cathode support, which is illustrated in section C. Finally, as the second electrode, which has the lowest heat transfer from the cathode, expands to the first electrode side, the current increases along the curve of the section D, and eventually returns to the initial adjustment amount.

At this time, the time taken for the current to rise as the first cathode expands and returns to the initial adjustment amount due to the expansion of the second electrode is called a settling time. According to FIG. 4, the settling time is about 30 minutes.

Meanwhile, the ratio between the current peak amount and the initial adjustment amount is called a current peak value, which is defined as follows.

Here, the current peak amount means when the expanded position of the cathode and each electrode gives the most current at a specific point by the heat of the heater, and the current peak value of the conventional cathode ray tube electron gun is about 150 to 200%. .

However, in the case of the electron gun configured as described above, in particular, the first electrode is due to the stress generated when the first electrode is combined with the insulating support and the stress of the metal itself remaining during the mold making of the electron beam through hole of the first electrode. Significant thermal expansion is shown. The thermal expansion amount of the first electrode is usually about 50 ~ 60㎛, which causes a problem of slowing down the settling time, as can be seen in FIG.

In addition, as the first electrode expands in the opposite direction to the cathode, the reaction rate of the cathode ray tube becomes slow, and in the case of a high resolution cathode ray tube, it is accompanied by a problem that it is difficult to raise a cutoff voltage above a predetermined voltage. .

In addition, as the amount of current reduction caused by the first electrode increases as the overshoot characteristic increases, the current peak value due to cathodic expansion becomes relatively high, resulting in a problem that the overshoot characteristic of the cathode ray tube is treated poor.

On the other hand, in the case of the ultra-high resolution electron gun, it is necessary to adjust the voltage applied to each cathode for color reproduction according to the reduction of the electron beam through hole of the first electrode. However, the adjustment voltage, that is, the cutoff voltage has a characteristic of decreasing when the size of the electron beam through hole of the control electrode is reduced and increasing when it is enlarged. Therefore, in order to have the same cutoff voltage while maintaining the reduced electron beam through hole of the control electrode in the ultra-high resolution electron gun, the thickness around the through hole of the control electrode must be made thin. However, when the thickness around the electron beam through hole of the control electrode is made thinner, a problem of more sensitive to thermal expansion occurs. Therefore, the cutoff voltage is lowered in the ultra-high resolution electron gun, which makes it difficult to adjust the voltage applied to the cathode for color reproduction, thereby making it difficult to manufacture a monitor or a TV chassis and increasing the cost.

The present invention has been made to solve the above problems, an object of the present invention is to improve the overshoot characteristics of the cathode current by minimizing the thermal deformation of the first electrode as a control electrode electron gun for cathode ray tube which can bring a faster stabilization To provide.

Furthermore, another object of the present invention is to provide an electron gun for a cathode ray tube, which is easy to manufacture a monitor or a TV chassis and is inexpensive by preventing the cutoff voltage from being lowered even if the thickness around the electron beam through hole of the ultra-high resolution electron gun becomes thin.

1 is a cross-sectional view showing the structure of a typical cathode ray tube

2 is an enlarged cross-sectional view illustrating an enlarged structure of an electron gun for a typical cathode ray tube.

Figure 3 is a graph showing the amount of current change according to the heater heating of the electron gun for the conventional cathode ray tube

Figure 4 is a graph showing the overshoot characteristics of the conventional electron gun for cathode ray tube

5 is a cross-sectional view showing the structure of an electron gun for a cathode ray tube according to the present invention;

6 is an enlarged cross-sectional view illustrating an enlarged structure of a first electrode of a cathode ray tube electron gun according to the present invention;

7 is a graph showing the amount of thermal expansion according to the plan view of the first electrode of the cathode ray tube electron gun according to the present invention

8 is a graph showing the overshoot characteristics of an electron gun for a cathode ray tube according to the present invention;

Explanation of symbols on the main parts of the drawings

22: cathode 24: first electrode

24a: through hole forming portion 24h: electron beam through hole

In order to achieve the above object, the cathode ray tube electron gun according to the present invention is formed of a plurality of cathodes for emitting the electron beam by the heating of the heater and the first electrode having an electron beam through hole formed perpendicular to the path of the electron beam and the electron beam In the electron gun for a cathode ray tube including a three-pole portion consisting of a second electrode for acceleration, the through-hole forming portion for forming the electron beam through hole of the first electrode is inclined toward the cathode, the through hole of the first electrode The forming portion is inclined such that the electron beam passing hole retracts 25 to 45 µm in the cathode direction, and in particular, the passing hole forming portion of the first electrode is inclined so as to retreat 35 µm in the cathode direction.

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

First, Figure 5 is a cross-sectional view showing a structure of a cathode ray tube electron gun according to the present invention, Figure 6 is an enlarged cross-sectional view of an enlarged structure of the first electrode of the cathode ray tube electron gun according to the present invention, Figure 7 is a cathode ray according to the present invention 8 is a graph showing the amount of thermal expansion according to the plan view of the first electrode of the conventional electron gun, Figure 8 is a graph showing the overshoot characteristics of the electron gun for cathode ray tube according to the present invention.

As shown in FIG. 5, the cathode ray tube electron gun 20 according to the present invention includes a heater 21 for generating heat by receiving power and a cathode support for supporting three cathodes 22 independent from each other on the front surface of the heater ( 23) and a first electrode 24 spaced at a predetermined interval on the front surface of the cathode 22 to serve as a common lattice of the three cathodes and to control the electron beam irradiated from the cathode; It is largely composed of a second electrode 25 spaced apart at regular intervals on the front surface to accelerate the electron beam.

In addition, the third electrode 26 and the fourth electrode 27 forming the prefocus lens on the front surface of the second electrode 25 are spaced apart from each other. In addition, a first acceleration focusing electrode 28a and a second acceleration focusing electrode 28b are provided on the front surface of the fourth electrode 24, and a focusing electrode 29 to which a high voltage is applied on the front surface of the acceleration focusing electrode; A shield cup 30 is provided on the front surface of the focusing electrode to shield the deflected leakage magnetic field.

Meanwhile, the plurality of electrodes 24 to 29 and the cathode support 23 are fused and fixed to the two insulating supports 31.

Each of the electrodes 24 to 29 is positioned at a predetermined distance from each other to be perpendicular to a path through which the electron beam passes so that the electron beam generated from the cathode 22 is controlled at a constant intensity to reach the screen. An oxide is attached to the cathode 22 to emit electrons by the heat generated by the heater 21.

In the cathode ray tube electron gun 20 configured as described above, the heater 21 generates heat by receiving a power supply (6.3V) from the stem pin 6 provided at one end thereof, and the cathode 22 located on the front of the heater has 720 to As the temperature rises to about 800 ° C, it emits hot electrons and irradiates the electron beam. The electron beam is controlled by the first electrode 24, which is a control electrode, and accelerated by the second electrode 25, which is an acceleration electrode, passing through the first and second acceleration focusing electrodes 28a and 28b to form a main lens. It passes through the focusing electrode 29 which is an electrode. Subsequently, the electron beam passes through a shadow mask serving as a color screening function and impinges on the phosphor surface to emit phosphor.

On the other hand, as shown in Figure 6, the structure of the first electrode of the cathode ray tube electron gun according to the present invention can be seen in detail.

First, the degree to which the peripheral portion (hereinafter referred to as "through hole forming portion 24a") forming the electron beam through hole 24h of the first electrode is inclined with respect to the plane perpendicular to the traveling direction of the electron beam is called a plan view. define. The plan view is measured by how much the electron beam passing hole 24h is actually retracted toward the cathode because the through hole forming portion 24a is inclined at a predetermined angle.

The first electrode of the conventional electron gun shown in FIG. 6 is shown by a dotted line, and the electron beam passing hole is formed to be perpendicular to the traveling direction of the electron beam shown by the arrow, and its plan view is usually about ± 10 μm, depending on the manufacturing limit. In contrast, the first electrode 24 of the electron gun according to the present invention is formed such that the passage hole forming portion 24a is inclined at a predetermined angle in the cathode direction so that the electron beam passage hole 24h is retracted in the cathode direction.

The plan view of the first electrode of the electron gun according to the present invention is about 25 to 45 μm, which means that the electron beam through-hole 24h is retracted about 25 to 45 μm in the direction of the cathode. In particular, the plan view of the first electrode is most preferably about 35㎛, the reason is as follows.

Hereinafter, a plan view of the first electrode and a thermal change amount of the first electrode will be described in detail with reference to FIG. 7.

7 is a graph showing the amount of thermal expansion according to the first electrode plan view of the cathode ray tube electron gun according to the present invention, the horizontal axis represents the first electrode plan view in units of 10㎛ and the vertical axis represents the heat according to the plan view of the first electrode The amount of expansion is expressed in units of μm.

First, the planar view of the first electrode of the conventional electron gun is about ± 10 μm. In this case, as described above, the first electrode is expanded about 50 μm toward the second electrode. Subsequently, as the plan view of the first electrode increases, that is, as the through hole forming portion is inclined and the electron beam through hole retreats in the cathode direction, the amount of expansion of the first electrode decreases to a certain point.

Next, when the planarity of the first electrode is approximately 35 µm, the expansion amount becomes minimum, and as the planarity becomes larger, the expansion amount increases again, and when the planarity becomes 55 µm or more, the expansion amount becomes larger than before. Can be.

Therefore, in order to minimize the amount of expansion of the first electrode, the first electrode planarity should be a value within an appropriate range.

In this case, when the first electrode planarity is about 25 to 45 μm, the expansion of the first electrode is about 20 to 30 μm, which is about 50% less than that of the conventional about 50 to 60 μm. have. That is, the through-hole forming portion of the first electrode should be inclined at a predetermined angle so that the electron beam through-hole retreats in the direction of the cathode by about 25 to 45 μm.

On the other hand, the overshoot characteristics of the cathode ray tube electron gun constructed as described above will be described as follows.

Fig. 8 is a graph showing the overshoot characteristics of the cathode ray tube electron gun according to the present invention in comparison with the prior art, in which the horizontal axis represents time in minutes and the vertical axis represents the amount of current in ㎂. The curve shown by the solid line represents the overshoot characteristic of the electron gun according to the present invention, and the dotted line represents the overshoot characteristic of the conventional electron gun.

As shown in FIG. 8, the overshoot characteristic of the electron gun according to the present invention is that the cathode first receives the heat of the heater and thermally expands to the first electrode side while the current rapidly increases along the curve along the section A, and the cathode support is The current decreases along the curve of the section B while receiving the heat of the cathode and performing thermal expansion in the opposite direction to the cathode. Subsequently, while the first electrode expands to the second electrode side with the heat conduction of the cathode, the current decreases along the curve of the section C ′, and finally, the second electrode with the lowest heat transfer from the cathode expands to the first electrode side. As the current increases along the curve of the D 'section, it eventually returns to the initial adjustment amount.

In other words, the electron gun for the cathode ray tube according to the present invention is formed so that the first electrode has a plan view of the range that the thermal deformation is minimized, it is more than conventional to expand the first electrode toward the second electrode, that is, away from the cathode It can be seen that the current reduction is also significantly reduced by 50% reduction. As a result, it is possible to quickly return to the initial adjustment amount when the current by the second electrode rises.

Therefore, compared with the conventional settling time of about 30 minutes, the time taken for stabilization of the cathode ray tube electron gun according to the present invention to about 20 minutes is greatly reduced.

In addition, the amount of reduction of the cathode current caused by the first electrode is remarkably reduced, resulting in a relatively low current peak due to cathode expansion. The current peak value shows good overshoot characteristics of about 80 to 140%.

The electron gun for the cathode ray tube according to the present invention inclines the through hole forming portion of the first electrode so that the electron beam through hole retreats in the cathode direction, thereby minimizing thermal deformation of the first electrode.

Therefore, as the amount of expansion of the first electrode is smaller than that of the related art, the first electrode can maintain a close distance to the cathode, thereby increasing the reaction speed of the cathode ray tube, and it is easy to raise the cutoff voltage above a certain voltage in the high resolution cathode ray tube. It is effective.

In addition, as the reduction amount of the cathode current due to the thermal deformation of the first electrode is reduced, the current peak value due to the cathode expansion is relatively lowered, thereby not only significantly reducing the problem of the overshoot characteristic of the cathode ray tube being reduced. Faster settling time can greatly contribute to improving the reliability of cathode ray tube.

In addition, in the case of the ultra-high resolution electron gun, even if the thickness around the electron beam through-hole of the first electrode is thin, the first electrode is less sensitive to thermal deformation than the prior art, thereby achieving stable background characteristics. As a result, it is possible to eliminate the problem of lowering the cutoff voltage and to easily adjust the voltage applied to the cathode for color reproduction, thereby facilitating the production of a monitor or TV chassis and reducing the production cost.

Claims (3)

An electron gun for a cathode ray tube including a plurality of cathodes that emit electron beams by heat generation of a heater, and a three-pole portion formed perpendicularly to a path of the electron beam and having a first electrode having an electron beam passing hole and a second electrode for accelerating the electron beam. In An electron gun for a cathode ray tube, characterized in that the through-hole forming portion forming the electron beam through-hole of the first electrode is inclined toward the cathode. The method of claim 1, The electron gun for the cathode ray tube, characterized in that the through-hole forming portion of the first electrode is inclined so that the electron beam through-hole retracts 25 to 45㎛ in the cathode direction. The method of claim 2, The electron gun for the cathode ray tube, characterized in that the through-hole forming portion of the first electrode is inclined so that the electron beam through-hole retracts 35㎛ in the cathode direction.