KR20020034459A - An Electron Gun for Color Cathode-ray Tube - Google Patents

Abstract

PURPOSE: An electron gun for color cathode ray tube is provided to improve an over-shooting phenomenon of cathode current by reducing a thermal deformation phenomenon of an acceleration electrode. CONSTITUTION: A heater(21) is used for generating heat. A cathode support body(23) is used for supporting three cathodes(22) formed on a front face of the heater(21). The first electrode(24) is used for controlling electron beams emitted from the cathodes(22). The second electrode(25) is installed at a predetermined interval from the first electrode(24). The second electrode(25) is used for accelerating the electron beams. The third electrode(26) and the fourth electrode(27) are installed on a front face of the second electrode(25). The first and the second acceleration focus electrodes(28a,28b) are installed on a front face of the fourth electrode(27). A focus electrode(29) and a shield cup(30) are formed in front faces of the first and the second acceleration focus electrodes(28a,28b). The electrodes(24-30) and the cathode support body(23) are fixed by two insulating support bodies(31).

Description

Electron Gun for Color Cathode-ray Tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for color cathode ray tubes, and more particularly, to an improvement of a three-pole structure composed of a cathode, a control electrode, and an acceleration electrode of a color cathode ray tube electron gun.

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

1 is a cross-sectional view illustrating a structure of a general cathode ray tube, in which a panel 1 having a fluorescent surface coated with R, G, and B fluorescent materials is provided on the inside thereof, and a back surface of the panel 1 is fused using frit glass. It forms an outer skeleton with a funnel (2). In the neck portion of the funnel 2, an electron gun 10 is formed which emits and accelerates and focuses electron beams 19 of three colors R, G and B.

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 path for correcting the trajectory so that the electron beam 19 strikes the phosphor 4 accurately. A magnet (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 spaced apart at predetermined intervals from the front surface of the cathode support 13 and the cathode 12 which support the heater 11 that generates heat according to the application of power and the three cathodes 12 independent from each other. The first electrode 14, which serves as a common lattice of the three cathodes 12, and the second electrode 15 spaced apart from each other at regular intervals.

In addition, the electrodes 14 and 15 are formed at regular intervals 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 periphery of the electron beam through holes 14h and 15h of the first and second electrodes 14 and 15 is formed perpendicular to the path of travel of the electron beam.

In this case, the first electrode 14 is called a control electrode because it controls the electron beam irradiated from the cathode 12, and the second electrode 15 pulls out and accelerates the hot electrons gathered on the surface of the cathode 12. It is called an acceleration electrode because it plays a role. The cathode 12, the first electrode 14, and the second electrode 15 are collectively called a three-pole portion.

In addition, a plurality of electrodes are provided in addition to the three-pole portion, and description thereof will be omitted herein.

Referring to the operation of the three poles in detail as follows.

First, when a constant voltage (6.3V) is applied to the heater 11, the heater 11 and the cathode 12 is heated to 720 ~ 800 ℃ by the heater resistance, the cathode 12 is the first electrode ( 14) It expands about 90 ~ 100㎂ to the side. In addition, the negative electrode support 13 supporting the negative electrode 12 receives heat from the negative electrode and expands by about 20 to 35 mm in the opposite direction to the first electrode 14. Subsequently, the first electrode 14 expands by about 50 to 60 kPa toward the second electrode 15 side, and finally, the second electrode 15 with the lowest heat transfer expands toward the first electrode 14 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 cathode ray tube electron gun, the horizontal axis represents time, the vertical axis represents the current change amount.

As shown in FIG. 3, while the heater receives 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. In this case, the combination of the current characteristics of the above 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, as the cathode receives heat from the heater and thermally expands to the first electrode side, the current rapidly increases along a curve according to the 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 ②. Subsequently, the first electrode expands to the second electrode side with the heat conduction of the cathode, thereby reducing the current as the cathode support, which is shown in section ③.

Finally, the second electrode with the slowest heat transfer from the cathode expands to the first electrode side 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 25 to 30 minutes.

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

Current peak value (%) = (Current peak amount / 200 mA) × 100

Here, the current peak amount means the amount of current when the cathode 12 and the expanded position of each electrode are given the most current at a particular point by the heat of the heater. In the case of the conventional electron gun for cathode ray tube, the current peak value is 150 to It is about 200%.

In the electron gun configured as described above, in particular, the stress generated when the first electrode and the second electrode are combined with the insulating support 31 and the stress of the metal itself remaining during the metal mold production of the electron beam through hole of the first and second electrodes. As a result, the first and second electrodes show a significant amount of thermal expansion. The thermal expansion amount of the first electrode is about 50 to 60 kPa, and the thermal expansion amount of the second electrode is about 15 to 25 kPa, which causes a problem of slowing down the settling time as shown in FIG. In particular, the return time of the original state due to thermal expansion of the second electrode has a close relationship with the settling time. If the current return time of the current due to thermal expansion of the second electrode is closely related to the settling time. If there is no change in current due to thermal expansion of the second electrode, the time point at which the current change due to thermal expansion of the first electrode ends is a stable start time. Therefore, the control of current by thermal expansion of the second electrode is a stabilization characteristic of the cathode ray tube. It's a big contribution to that.

Therefore, the larger the change in the current due to the thermal expansion of the second electrode, the longer the settling time, which often leads to a problem of being treated as a poor overshoot characteristic of the cathode ray tube. On the other hand, in the case of the ultra-high resolution electron gun, the shrinkage, spacing, thickness, etc. of the electron beam passing holes of the first and second electrodes should be small, and the voltage applied to each cathode for color reproduction should be adjusted. However, the control voltage, that is, the cut-off voltage has a problem that the smaller the size of the electron beam through hole of the control electrode, the smaller the spacing and thickness, the more sensitive to thermal expansion.

Therefore, the cut-off voltage in the ultra-high resolution electron gun is lowered, making it difficult to adjust the voltage applied to the cathode for color reproduction, which makes it difficult to manufacture a monitor or a TV chassis and increases the cost.

Accordingly, the present invention is 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 second electrode of the acceleration electrode for a cathode ray tube that can bring a faster stabilization To provide an electron gun.

Another object of the present invention is to reduce the thickness of the electron beam through hole of the ultra-high-resolution electron gun, and to reduce the cut-off voltage even when the gap between the first and second electrodes is small, making it easy and inexpensive to manufacture a chassis of a monitor or a television. To provide a conventional gun.

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 a typical cathode ray gun electron gun;

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

4 is a graph showing the overshoot characteristics of a conventional electron gun for cathode ray tubes,

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 second electrode of a cathode ray tube electron gun according to the present invention;

7 is a cross-sectional view showing a second electrode plan view of an electron gun for a cathode ray tube 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, and

9 is a cross-sectional view showing an electron gun structure of another embodiment according to the present invention.

<Description of Symbols for Major Parts of Drawings>

22: cathode 25: second electrode

25a: through hole forming portion 25b: electron beam through hole

Technical means of the present invention for achieving the above object, a plurality of cathodes for emitting an electron beam by the heating of the heater, a first electrode for controlling the electron beam emitted from the cathode, and a second for acceleration of the electron beam An electron gun for a cathode ray tube including a three-pole portion composed of electrodes, wherein the through-hole forming portion forming the electron beam through-hole of the second electrode is at least partially toward the opposite direction of the cathode with respect to the vertical plane of the second electrode arrangement of the electron beam path. It is configured to protrude.

In addition, the passage hole forming portion of the second electrode may protrude from 20 to 50 μm toward the opposite direction of the cathode with respect to the vertical plane of the second electrode arrangement of the electron beam path, and preferably from about 35 μm.

In addition, the through-hole forming portion of the first electrode is preferably at least partially protruding toward the cathode direction with respect to the vertical plane of the electron beam path.

According to another aspect of the present invention, there is provided a three-pole portion including a plurality of cathodes emitting an electron beam by heat generation of a heater, a first electrode controlling an electron beam emitted from the cathode, and a second electrode for accelerating the electron beam. In the electron gun for a cathode ray tube, the through-hole forming portion for forming the electron beam through hole of the first electrode is configured to protrude at least partially toward the cathode direction with respect to the vertical plane of the first electrode arrangement path of the electron beam path.

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 view showing the structure of a cathode ray tube electron gun according to the present invention, Figure 6 is an enlarged cross-sectional view of an enlarged three-pole structure of the cathode ray tube electron gun according to the present invention, Figure 7 is a cathode ray tube electron gun according to the present invention 8 is a graph showing the amount of thermal expansion according to the plan view of the second electrode, 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 the first electrode 24 spaced apart at regular intervals on the front surface of the cathode 22 to serve as a common lattice of the three cathodes 22 and to control the electron beam irradiated from the cathode 22; It is largely composed of a second electrode 25 spaced apart at regular intervals on the front surface of the first electrode to accelerate the electron beam.

In addition, the third electrode 26 and the fourth electrode 27 are provided on the front surface of the second electrode 25 so as to be spaced apart from each other, thereby forming a prefocus lens and a multi-stage focusing lens together with the triode. 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 27, 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 30 and the cathode support 23 are fusion-fixed to the two insulation supports 31. Each of the electrodes 24 to 30 is positioned at a predetermined interval to be perpendicular to a path through which the electron beam passes so that the electron beam generated from the cathode 22 can be controlled to a constant intensity to reach the screen. An oxide is attached to the cathode 22 so as to emit electrons by the heat generated by the heater 21.

The electron gun 20 for the cathode ray tube configured as described above receives the power (6.3V) from the stem pin 6 installed at one end, and the heater 21 generates heat, and the cathode 22 located at the front of the heater 21 is As the temperature rises to about 720 ~ 800 ℃, the hot electrons are emitted and the electron beam is irradiated. The electron beam is controlled by the first electrode 24 as a control electrode, accelerated by the second electrode 25 as the acceleration electrode, and passes through the first and second acceleration focusing electrodes 28a and 28b. It passes through the focusing electrode 29 which is a lens formation electrode. Subsequently, the electron beam 19 passes through the shadow mask 3 which performs the color discrimination function and impinges on the fluorescent surface 4 to emit light.

On the other hand, as shown in Figure 6, the structure of the second 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 25a") forming the electron beam through hole 25h of the first electrode is inclined with respect to the plane perpendicular to the traveling path of the electron beam is called a plan view. define. The plan view can measure how the through hole forming portion 25a is inclined at a predetermined angle so that the electron beam through hole 25h actually retreats in the opposite direction of the cathode.

The second 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. Here, the direction of the arrow indicates the expansion direction of each electrode due to thermal expansion. In contrast, the second electrode 25 of the electron gun according to the present invention is formed such that the passage hole forming portion 25a is inclined at a predetermined angle in the opposite direction of the cathode so that the electron beam passage hole 25h is retracted in the opposite direction of the cathode. . That is, the electron beam through hole forming portion of the second electrode 25 is formed to protrude toward the opposite side of the cathode with respect to the vertical plane of the second electrode arrangement of the electron beam path.

The plan view of the second electrode of the electron gun according to the present invention is about 20 to 50 µm, which means that the electron beam through hole 25h is retracted about 20 to 50 µm in the opposite direction of the cathode. In particular, the plan view of the second electrode 25 is most preferably about 35㎛, the reason is as follows.

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

7 is a graph showing the amount of thermal expansion according to the plan view of the second electrode of the electron gun for cathode ray tube according to the present invention, the horizontal axis is a plan view around the ball of the second electrode in units of 10㎛, the vertical axis is a plan view of the second electrode The amount of thermal expansion according to the above is expressed in units of μm.

First, it can be seen that the second electrode expands by about 15 to 25 μm in the opposite direction of the cathode. As the plan view of the second electrode increases, that is, as the through hole forming portion is inclined, the electron beam through hole retreats in the opposite direction to the cathode. To this point, the amount of expansion of the second electrode is reduced.

Next, when the planarity of the second 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 second electrode, the planar view of the second electrode should be within an appropriate range.

In this case, when the planarity of the second electrode is about 20 to 50 μm, the expansion amount of the second electrode is about 10 to 15 μm, which is about 40% less than that of the conventional about 15 to 25 μm. have. That is, the through-hole forming portion of the second electrode should be inclined at a predetermined angle so that the electron beam through-hole retreats in the opposite direction of the cathode by about 20 to 50 μm than conventionally.

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

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 heat from the heater and thermally expands toward the first electrode, and the current rapidly increases along the curve according to the section. The current decreases along the curve of section ② while receiving heat from the cathode and performing thermal expansion in the opposite direction to the cathode. Subsequently, as the first electrode expands toward the second electrode with the heat conduction of the cathode, the current decreases along the curve of section 3 ', and finally, the second electrode with the lowest heat transfer from the cathode is in the opposite direction to the cathode. As it expands, the current rises along the curve ④ 'and eventually returns to the initial adjustment.

That is, the electron gun for the cathode ray tube according to the present invention is formed to have a plan view in a range that becomes a plan view of a range in which the thermal deformation of the second electrode is a minimum, so that the second electrode in the opposite direction of the cathode, that is, It can be seen that the expansion in the closer direction is reduced by about 40% compared to the conventional, the amount of current is significantly reduced. As a result, it is possible to quickly return to the initial adjustment amount when the current to the second electrode rises.

Therefore, compared with the conventional stabilization time of about 25 to 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 change in the cathode current caused by the second electrode is significantly reduced, resulting in a relatively low current peak value due to cathode expansion. The current peak value is about 80 to 140%, indicating good overshoot characteristics.

In addition, as shown in FIG. 9 as another embodiment of the present invention, when the first electrode of about 25 to 45 kW is applied to the cathode direction plan view of the first electrode, the thermal expansion amount of the first electrode is equal to the second electrode. It was shown that the change in the direction of about 20 to 30㎂ decreases by about 50% compared to the conventional first electrode. The over shoot characteristic of the cathode ray tube using the first electrode has the same effect as in FIG. 8.

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

Therefore, as the amount of expansion of the second electrode is smaller than that of the related art, as the ultra-high resolution increases, the electron beam through hole of the first and second electrodes becomes smaller, the thickness around the through hole becomes thinner, and the distance between the first and second electrodes becomes smaller. Even though the cut-off voltage is prevented from being lowered, it is effective to provide a low cost electron tube for cathode ray tube, which is easy to manufacture a chassis of a monitor or a TV.

In addition, as the reduction amount of the cathode current due to the thermal deformation of the second electrode is reduced, the current peak value due to the cathode expansion is relatively lowered, and the problem that the overshoot characteristic of the cathode ray tube is poor is significantly reduced. Faster settling time can greatly contribute to improving the reliability of cathode ray tube.

Claims (5)

In a cathode ray tube electron gun comprising a plurality of cathodes comprising a plurality of cathodes for emitting an electron beam by the heating of the heater, a first electrode for controlling the electron beam emitted from the cathode, and a second electrode for accelerating the electron beam, An electron gun for a cathode ray tube, characterized in that the through-hole forming portion for forming the electron beam through hole of the second electrode is formed to at least partially protrude toward the opposite side of the cathode with respect to the vertical plane of the second electrode arrangement of the electron beam path. The method of claim 1, An electron gun for a cathode ray tube, wherein the passage hole forming portion of the second electrode protrudes from 20 to 50 μm in a direction opposite to the cathode with respect to a vertical surface of the second electrode arrangement of the electron beam path. The method of claim 2, The electron gun for a cathode ray tube, characterized in that the through-hole forming portion of the second electrode protrudes about 35㎛ toward the opposite direction of the cathode with respect to the vertical plane of the second electrode arrangement of the electron beam path. 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 protrudes at least partially toward the cathode direction with respect to the vertical plane of the first electrode arrangement of the electron beam path. In a cathode ray tube electron gun comprising a plurality of cathodes comprising a plurality of cathodes for emitting an electron beam by the heating of the heater, a first electrode for controlling the electron beam emitted from the cathode, and a second electrode for accelerating the electron beam, 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 protrudes at least partially toward the cathode direction with respect to the vertical plane of the first electrode arrangement of the electron beam path.