KR100884794B1 - Electron gun for multi-media monitor - Google Patents

Abstract

According to the present invention, the electron gun includes a cathode, a control electrode and a screen electrode, and a plurality of focusing electrodes for focusing and accelerating the electron beam, and the thickness of the control electrode is T mm and passes through the electron beam formed on the control electrode. When the diameter of the ball is D mm,?, The value obtained by dividing the thickness by the diameter, is 0.233 or more.

Electron gun, electrode, current density, battery beam through hole

Description

Electron gun for multimedia cathode ray tube {Electron gun for multi-media monitor}

1 is a graph showing a relationship between a drive voltage and a cathode current applied to an electron gun of a cathode ray tube;

2 is a cross-sectional view showing a triode of an electron gun according to the present invention;

3 is a graph showing a relationship between a cathode drive voltage and a cathode current.

The present invention relates to an electron gun for a cathode ray tube, and more particularly, to an electron gun of a cathode ray tube for multimedia with improved triode.

Recently, color cathode ray tubes used as computer display monitors are required to have high resolution, high brightness quality and low price. In addition to the high brightness of images, the spread of asymmetric distal subscriber lines (ADSL) and cable TVs adds the capability of a television tuner or video capture to a personal computer, so that TV broadcasts can be viewed and recorded. Various computers are commercialized. Therefore, the cathode ray tube for a display monitor should be able to simultaneously display a still image, character information and a moving image.

In such a display monitor cathode ray tube, in order to realize high brightness, there is a method of increasing the current value of the cathode, improving the utilization efficiency of the electron beam, and improving the luminous efficiency of the fluorescent surface.

In the case of increasing the current of the cathode, a high cathode drive voltage is required to emit a large amount of current. Saturation occurs and the electron beam spreads. This makes the screen more explanatory at high currents on the screen.

In order to improve this, the stable amplification characteristics of the chassis circuit can form an accurate square wave even in the amplitude of a large signal, and it is necessary to supplement the circuit components with high reliability and capacity so that the response speed is not delayed. do.

In view of the foregoing, a method of increasing the current density while reducing the cost of implementing the circuit is to lower the spot-ket off voltage applied to the cathode of the electron gun. In this case, however, the area of application of the cathode beam becomes large. This lowers the focus characteristic.

In the state where the spot cut-off voltage is lowered, the decrease in the focus characteristic reduces the electron beam passing hole diameter of the cathode of the electron gun and the control electrode adjacent to the electron gun, thereby reducing the crossover diameter of the electron beam at the three poles of the electron gun. The beam diameter can be reduced by reducing the aberration of the prefocus lens formed in the triode. However, in this case, since the diameter of the control electrode is substantially very small, the assembly of the electron gun becomes difficult.

An example of a conventional electron gun for solving the above problems is disclosed in Japanese Laid-Open Patent Publication No. 1999-224618.

The disclosed electron gun has first, second and third electrodes sequentially installed from a cathode, and a modulation electrode is provided between the second electrode and the third electrode.

US Patent No. 5,689,158 discloses an electron gun in which a plurality of electron beam through holes are provided for each of the electron guns in the control electrode and the screen electrode to improve focus characteristics even at high luminance. The disclosed electron gun is difficult to assemble because a plurality of electron beam through holes are formed in the control electrode and the screen electrode, and the number of electrodes to be controlled increases, which makes it difficult to apply practically.

 Korean Unexamined Utility Model Publication No. 1999-033989 includes three cathodes and a heater for heating the cathodes and six electrodes heated in the heater to focus electrons generated from the cathode to form an electron beam. After providing an insulator of a predetermined thickness on one side of the second electrode for accelerating the electrons generated in the to form an electrode portion of a predetermined thickness on the other side of the insulator, the voltage of the second electrode is applied to this electrode portion One electron gun is disclosed.

Korean Unexamined Utility Model Publication No. 1999-008925 discloses an example of a multimedia type electron gun device.

In the disclosed electron gun device, electrons emitted from several cathodes are focused through a first electrode means, a second electrode, and a main lens portion to a screen, and the first electrode means is composed of two first and second electrodes, A fixed spacer is inserted between the first electrode and the second electrode and between the first electrode and the second electrode, and a hole is formed in the center of the fixed spacer so that the electron beam can pass therethrough.

An object of the present invention is to provide an electron gun of a cathode ray tube for multimedia with a low control voltage of the cathode and improved focus performance.

Another object of the present invention is to provide an electron gun of a cathode ray tube for multimedia having high brightness and low resolution and high brightness and low brightness of about 100 cd / m 2 used in a general personal computer.

In order to achieve the above object, the electron gun of the cathode ray tube for multimedia of the present invention

A cathode, a control electrode and a screen electrode, and a plurality of focusing electrodes for focusing and accelerating the electron beam,

The thickness of the control electrode is T mm, and when the diameter of the electron beam through hole formed in the control electrode is Dmm, β, the value obtained by dividing the thickness by the diameter, satisfies 0.233.

In the present invention, the β value is greater than or equal to 0.223 and smaller than 0.316, and the diameter Dmm of the electron beam through hole formed in the control electrode is preferably set to be larger than about 0.3 mm.                     

The electron gun of the cathode ray tube for multimedia of another aspect of the present invention for achieving the above object comprises a cathode, a control electrode and a screen electrode, and a plurality of focusing electrodes for focusing and accelerating the electron beam,

The thickness of the control electrode is called T mm,

When the area of the electron beam through hole of the control electrode is A, the circumference is C, and their relationship is 2 x (A / C) ^0.5 = DS.

It is characterized in that M which is the value obtained by dividing the thickness by the DS is 0.222 or more.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

The cathode ray tube for multimedia according to the present invention should be capable of realizing high brightness, low resolution, low brightness and high resolution. However, since the monitor is driven at a higher frequency than a normal television, a drive voltage of 50 V is usually applied due to the limitation of the commercial frequency band. A typical cathode ray tube can emit about 320 mA when a drive voltage of 50 V is applied as shown in FIG. 1, but at least 600 mA of beam current is required to obtain a luminance of 300 cd / m 2.

 Figure 2 shows an embodiment of the electron gun with improved drive characteristics.

Referring to the drawings, the electron gun of the cathode ray tube includes a cathode 21, a control electrode 22, and a screen electrode 23 forming a triode, and are sequentially installed from the screen electrode 23 to focus and accelerate the electron beam. It includes a plurality of electrodes (not shown).                     

In the electron gun, a voltage of which the cathode spot cut-off voltage applied to the cathode is lowered from 122 V to 50 to 80 V is applied to implement the high brightness and the high resolution. A voltage of 0v is applied to the control electrode, a voltage of 400 to 1000v is applied to the screen electrode 23, and a voltage of 6 to 10kv is substantially applied to an electrode adjacent to the screen electrode 23.

On the other hand, as described above, when the cathode spot cut-off voltage is lowered, the electron beam quality is deteriorated by about 20 to 40% in the tripolar region of the electron gun, and the focus characteristic is also deteriorated. It offset by improving the thickness (Tmm) of (22) and the diameter (Dmm) of the electron beam through-hole 22H. In more detail, the thickness of the control electrode 22 is referred to as T mm, the diameter of the electron beam through hole 22H formed in the control electrode 22 is referred to as Dmm, and the thickness of the control electrode 22 is defined as Dmm. When the value obtained by dividing (Tmm) by the diameter (Dmm) is β (β = T mm / Dmm), the thickness Tmm of the control electrode 22 and the diameter of the electron beam through hole ( D mm) was set to cancel the focus specific degradation. Herein, the diameter Dmm of the electron beam through hole 22H was set to the length of the shortest distance passing through the center of the electron beam through hole. On the other hand, the β value is preferably to have a range of inequality 0.222 ≤ β <0.316. When the β value is set in such a range, the diameter (D mm) of the electron beam passing hole 22H formed in the control electrode 22 is preferably set to be larger than 0.3, but more specifically, 0.3 to 0.4 mm. This is preferable. If the through hole diameter of the control electrode is smaller than 0.3mm, the diameter of the nozzle inserted into the through hole of the control electrode must be made very small in the assembly process of the cathode and the control electrode, thus making it difficult to process the nozzle and to secure productivity. .

When the diameter of the electron beam through hole (D mm) formed in the control electrode 22 is reduced, the area emitted from the surface of the cathode 21 becomes small, which causes a lifetime problem by increasing the load of the cathode. In order to improve this, it is preferable to use an impregnated cathode.

As another embodiment of the present invention, when the electron beam through hole formed in the control electrode 22 constituting the electron gun is non-circular, it can be converted into a value twice the value obtained by dividing the square root by the circumferential ratio of the area of the electron beam through hole. That is, when the thickness of the control electrode 22 is T mm, the area of the electron beam through hole of the control electrode is A, the circumference is C, and their relationship is 2 x (A / C) ^0.5 = DS. The focus specification could be improved by setting the thickness of the control electrode 22 and the electron beam through hole so that M, the thickness divided by the DS, became 0.222 or more. Herein, the M value is preferably set to have a range of inequality 0.222 ≦ M <0.316.

As described above, the action of the electron gun for the color cathode ray tube with improved triode is as follows.

 When the spot cut-off voltage (EK-ECI) is applied to the cathode 21 of the electron gun 20 according to the present invention at 50 to 80 V, and a predetermined voltage is applied to each electrode constituting the electron gun, each cathode ( 21, a signal voltage is applied, and the electron beam is soon to be launched toward the screen surface. A cathode lens is formed between the cathode 21, the control electrode 22, and the screen electrode 23, and a prefocus lens is formed between the screen electrode 23 and an electrode adjacent thereto. A focusing lens is formed between the electrodes to focus and accelerate the electron beam.

Therefore, the electron beam emitted from the cathode 21 is focused and accelerated by the pre-focused and accelerated focusing lenses by the cathode lens and the prefocus lens and landed on the fluorescent film. In this process, the spot cut-off voltage of 50 to 80 V, which is lower than the spot cut-off voltage of the cathode ray tube for a computer, which is generally used at about 120 volts, is applied to the cathode 21, so that the electron beam current emitted even at a low amplitude cathode drive voltage is applied. Sensitively increased. The decrease in the focus characteristic caused by the increase of the beam current is 0.223 when the value obtained by dividing the thickness Tmm of the control electrode 22 by the diameter Dmm is β (β = T mm / Dmm). By setting the thickness (T mm) and the size of the electron beam through hole (D mm) of the control electrode 22, the divergence of the electron beam can be suppressed by the cathode lens, so that the diameter of the electron beam bundle can be reduced in the triode. In other words, the deterioration of the focus characteristic is prevented by reducing the aberration by the prefocus lens.

The effects as described above will become more apparent through the experiments of the inventors.

Experiment 1

In this experiment, the electron beam size was measured by varying the thickness of the control electrode, the diameter of the electron beam through hole, and the distance between the control electrode and the screen electrode according to the spot cutoff voltage applied to the cathode forming the triode of the electron gun. Could.

Table 1

                  Experimental Example     Experimental Example 1  Experimental Example 2   Experimental Example 3 Voltage applied to the screen electrode       600      600     600  Spot cutoff voltage applied to the cathode (volt)       62      62     62  Diameter of electron beam through hole of control electrode (D μm)      360      330     300  Control Electrode Thickness (T ㎛)      90      80     70   Tmm / D mm     0.25      0.24     0.233  Electron beam diameter (㎛)     0.406      0.411     0.417  Current when 50V AC signal (video signal) is applied     850

As can be seen from Table 1, the thickness of the control electrode lowers the spot cutoff voltage applied to the cathode and increases the beam diameter on the screen even in a low current region by increasing the beam divergence angle due to the low cutoff voltage. By controlling the ratio of the diameter of the electron beam passing hole and the strong triode lens at the triode, it was possible to secure the character resolution in the low current region, which is the character region. It is also found that high cathode drive characteristics can be achieved at the same cathode signal voltage.

In Table 1, the screen voltage level used for a typical cathode ray tube for a computer is 600v applied to the screen electrode, and the spot cut-off voltage (volt) applied to the cathode is 62v lower than that of a conventional cathode ray tube. The thickness of the control electrode (T mu m) and the diameter (D mu m) of the electron beam through hole of the control electrode were changed to change their ratio (T / D) to compare the size of the electron beam focused on each screen.                     

Table 1 shows that the beam size on the screen gradually decreases as the value of T / D increases. In Table 1, when the T / D value is 0.233 or more, the beam size on the screen can be reproduced on the screen even at the spot cutoff voltage applied to the low cathode. It can be shown that the performance of the focus can be secured by adjusting the T / D.

Comparative Example

In this experiment, the beam diameter of the electron beam current (about 200 mA) at 120 cd / m 2 was measured on the screen while varying the spot cutoff voltage applied to the cathode that forms the triode of the electron gun used in the conventional cathode ray tube. Had to get.

TABLE 2

              Comparative example     Comparative Example 1  Comparative Example 2  Spot cutoff voltage applied to the cathode (volt)       122      62 Current when 50vdml cathode signal is applied (IK㎂)        320       850  Diameter of electron beam through hole of control electrode (D μm)      360      360   Thickness of control electrode (T㎛)       65      65      Tμm / D μm              0.18  Electron beam diameter (mm) (IK = 200㎂)     0.43      0.51

As can be seen from Table 2, the spot cutoff voltage applied to the cathode was changed from 122V to 62V in the electron gun structure using the same control electrode as the diameter of the electron beam through hole of the control electrode, respectively, 360 μm and the thickness of 65 μm, respectively. The beam currents generated when the same cathode applied voltage of 50V was applied were compared. The cathode generation current IK of Comparative Example 2 shows that it has a current increase characteristic of about 850 ㎂, that is, about 2.6 times that of Comparative Example 1. A much higher current response can be obtained when the same cathode voltage is applied. However, in this case, when the same 200 mA, which is a beam current band used as a character screen, is generated, the electron beam diameter at the lower surface of the comparative example 1 is lower than that of the comparative example 2, which has a lower cutoff voltage. This indicates that the image quality characteristics are so bad. It can be seen that there is a problem with the computer that requires the implementation of the advanced character.

Therefore, it is necessary to design the character area, which is the basic area of the computer, so that the resolution does not fall in the low luminance area and the electron beam size on the screen does not deteriorate.

Experiment 2

In this experiment, the spot cut-off voltage of 62v is applied to the cathode that forms the triode of the electron gun, and when the beam is focused on the screen by generating the same 200 ㎂ load current, which is used as a letter, the thickness of the control electrode (Tmm) and When the relationship between the diameter (Dmm) of the electron beam through hole, that is, the value obtained by dividing the thickness (T mm) of the control electrode by the diameter (D mm) of the electron beam is β, the relationship between the value of β and the electron beam diameter is measured. Got it.

TABLE 3

   Tmm / D mm        β   Beam diameter (mm) Finding between cathode and control electrode (L1 mm)    0.12 / 0.36     0.333    0.369     0.061    0.11 / 0.36     0.316    0.371     0.070    0.09 / 0.36     0.250    0.377     0.107    0.08 / 0.36     0.222    0.43     0.123    0.07 / 0.36     0.194    0.452     0.138    0.06 / 0.36     0.167    0.53     0.095

The electron beam diameter of the cathode ray tube used for multimedia is not deteriorated in the character area even when compared to the electron beam diameter of the conventional cathode ray tube. Therefore, the electron beam diameter of the cathode ray tube should be 0.222 or more, as shown in Table 3. In Table 3, the change of the beam diameter on the screen was observed while fixing the diameter of the control electrode and changing the thickness of the control electrode. Especially when it becomes 0.222 or less, a load diameter increases rapidly.

On the other hand, if the thickness of the through hole of the control electrode is increased to increase the value of β, the thickness of the study moves to the surface side of the cathode, and the distance between the control electrode and the cathode surface becomes closer.

The gap between the cathode 21 and the control electrode 22 should be maintained at least about 70 μm in order to ensure the error of the insertion of the cathode during the assembly process of the electron gun and the control electrode and the margin of the cathode thermal deformation. In addition, the gap between the cathode 21 and the control electrode 22 should be secured in consideration of surface imprinting, short-circuit, and white balance characteristics of the cathode due to process dispersion and thermal strain dispersion. When the gap between the cathode 21 and the control electrode 22 is 70 μm, the β value is 0.316 from Table 3, so rather than the thickness Tmm of the control electrode 22, the diameter (D mm) of the electron beam through-hole thereof. Divided by.

 Therefore, if the value of β is in the range of inequality 0.233 ≦ β ≦ 0.316, the cathode loading radius of the beam can be enlarged through a low spot cutoff voltage, and the CDT can be discharged at a low voltage as high as CPT. In addition, it is possible to secure a small beam diameter even in the implementation of the image of the low current region to implement the character screen.

On the other hand, when the electron beam through hole formed in the control electrode 22 is non-circular, it is possible to convert the area of the electron beam through hole by the circumferential ratio and convert it to twice the value of the square root. In this case, the area of the electron beam through hole is A. Where the circumferential ratio is C and their relationship is 2 x (A / C) ^0.5 = DS. Setting could improve the focus specification. The M value could be calculated in the same manner as in the above-described limitation of the circular electron beam through hole of the control electrode, and it was found that the M value is preferably set to have an inequality of 0.222 ≦ M <0.316.

As described above, the cathode ray tube electron gun for multimedia according to the present invention increases the amount of electric current by about twice at 50 V electron gun drive voltage by applying a low spot cutoff voltage to the cathode constituting the triode and defining the control electrode and the electron beam through hole formed therein. The effect was obtained and the spot size of the electron beam could be reduced by more than 20%.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (10)

A cathode, a control electrode and a screen electrode, and a plurality of focusing electrodes for focusing and accelerating the electron beam, When the thickness of the control electrode is T mm and the diameter of the electron beam through hole formed in the control electrode is Dmm, β, the value obtained by dividing the thickness by the diameter, satisfies the inequality 0.222 ≤ β ≤ 0.316, Electron gun of the cathode ray tube for multimedia, characterized in that the cathode spot cut-off voltage applied to the cathode is 50 to 80V. delete The method of claim 1, Electron gun of the cathode ray tube for multimedia, characterized in that the minimum diameter of the electron beam through hole formed in the control electrode is larger than 0.3mm and smaller than 0.4mm. delete A cathode, a control electrode and a screen electrode, and a plurality of focusing electrodes for focusing and accelerating the electron beam, When the thickness of the control electrode is T mm and the diameter of the electron beam through hole formed in the control electrode is Dmm, β, which is the value obtained by dividing the thickness by the diameter, satisfies the inequality 0.222 ≤ β <0.316, Electron gun of the cathode ray tube for multimedia, characterized in that the cathode spot cut-off voltage applied to the cathode when the voltage of 0V is applied to the control electrode and 600V to the screen electrode is applied to the cathode . A cathode, a control electrode and a screen electrode, and a plurality of focusing electrodes for focusing and accelerating the electron beam, The thickness of the control electrode is called T mm, When the area of the electron beam through hole of the control electrode is A, the circumference is C, and their relationship is 2 x (A / C) ^0.5 = DS. An electron gun of a cathode ray tube for multimedia, characterized in that M, which is a value obtained by dividing the thickness by DS, satisfies the inequality 0.222? M? 0.316. delete The method of claim 6, Electron gun of the cathode ray tube for multimedia, characterized in that the minimum diameter of the electron beam through hole formed in the control electrode is larger than 0.3mm and smaller than 0.4mm. The method of claim 6, Electron gun of the cathode ray tube for multimedia, characterized in that the cathode spot cut-off voltage applied to the cathode is 50 to 80V. The method of claim 6, A voltage of 0 V is applied to the control electrode, and a voltage of 600 V is applied to the screen electrode.

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