KR890002362B1 - Electron gun - Google Patents

Abstract

The aperture diameter of the auxiliary electrode exceeds that diameter of the electron lens which correponds to the aperture diameter of a third and fourth grid. A voltage between the third and fourth grids is applied to the auxiliary electrode to cut off disturbing electrostatic fields in the tube neck. The diameters of the apertures of the auxiliary electrode are greater than the diameters of the apertures of the third, fourth grids in proportion to the distance between the third and fourth grids. Instead of a bipotential lens, a unipotential, quadpotential or periodical potential lens may be used.

Description

Electron gun for cathode ray tube

1 is a side cross-sectional view showing an embodiment of the present invention, wherein a color water gun.

2 (a) and 2 (b) are cross-sectional views of the Y-Z and X-Z axes of FIG.

3 (a), 3 (b) and 4 are equipotential line distribution diagrams for explaining the present invention, and FIGS. 3 (a) and 3 (b) are second (a). Sectional drawing corresponding to FIG. And 2 (b), respectively.

4 is a cross-sectional view of a coaxial cylindrical lens.

The axial potential distribution diagram in FIG. 5 and FIG.

6 (a) and 6 (b) are perspective views of the electrode used in the embodiment of FIG.

7 (a) and 7 (b) and 8 (a) and 8 (b) show another embodiment of the present invention. FIGS. 7 (a) and 8 (a) and 7th (b) and FIG. 8 (b) are sectional drawing in YZ-axis and XZ-axis, respectively.

9 is a cross-sectional view showing a part of the resistor.

An embodiment of the present invention when using the resistor of FIG. 10 and FIG.

11 is an electrical diagram of FIG.

Another embodiment corresponding to FIG. 12. FIG.

13 (a), 14 (b) and 14 (c) are side cross-sectional views showing another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: electron gun 2: insulation support

3a, 3b, 3c: electron beam 13: third grid

14 fourth grid 15 converging electrode

16: auxiliary electrode 54: resistor

The present invention relates to a cathode ray tube electron gun and to an electrostatic lens structure of an electron gun for focusing at least one, preferably more, electron beams.

The cathode ray tube is provided with at least one electron gun and forms an electron beam spot on a predetermined target by the electron gun.

One very important factor that determines the performance of the cathode ray tube with respect to this electron gun is the spot diameter of the electron beam on the target target.

Naturally, the smaller the spot diameter on the target is, the more desirable it is, but the esports diameter is determined by the performance of the electron gun. In general, the electron gun is composed of a portion generating the electron beam and the main lens portion for accelerating the electron beam. One effective means of improving the performance of the electron gun is to improve the performance of the main lens portion.

Most of the main lens parts are formed by disposing a plurality of electrodes having holes on the coaxial as an electrostatic lens and applying a predetermined electric potential.

There are some kinds of electrostatic lenses according to the difference in electrode configuration, but basically, the potential of the electrode changes smoothly by increasing the diameter of the electrode hole, forming a large aperture lens, or by increasing the distance between the electrodes. As a result, the lens performance can be improved by forming a long focus lens.

However, since the electron gun for cathode ray tubes is generally used by being enclosed in a thin glass cylinder, the hole of the electrode, that is, the lens diameter is physically limited, and then a condensing electric field formed between the electrodes is unnecessary. The distance between electrodes is limited in order not to be affected by an electric field. In particular, when several electron guns are used in a line, such as a color receiving tube, the smaller the electron gun spacing (Sg), the easier it is to concentrate multiple electron beams to one point on the front of the screen and to deflect power. Is also advantageous.

Therefore, in order to make the electron gun spacing Sg small, the hole of the electrode must be made smaller.

In the situation of the electron gun for cathode ray tube as described above, in order to further improve the lens performance, a long focal lens is formed which is equivalent to the case where the distance between the cathodes is increased in a small state, and US patent No. 3,863,091 US Pat. No. 3,895,253, US Pat. No. 3,995,194, US Pat. No. 3,932,786, US Pat. No. 4,124,810, and the like.

However, the electron lenses shown in US Patent No. 3,863,091 and US Patent No. 3,895,253 both have a high voltage of 25-30 KV of the anode applied to the first electrode G3 (third grad) of the main lens unit, so the low voltage of the electron beam generating unit is applied. Since it is easy to cause discharge between electrodes, it is not practical. In addition, in the lens of U.S. Patent No. 3,995,194 and U.S. Patent No. 4,124,810, three potential electrodes of cylindrical diameter are sequentially turned into low potential-medium potential-high potential to form a gentle potential change. To achieve the best lens performance, the length of the medium potential electrode is substantially the same as the radius of the electrode hole and further lens performance cannot be improved.

Therefore, in order to improve the performance of the lens, a somewhat bipolar lens of US Patent No. 3,932,786 is proposed, but in such an electron gun, a resistor placed next to several electrodes is too small. Therefore, there is no suitable thing for practical use, and it is very difficult to manufacture because the potential must be taken out from the small resistor at a smaller interval. Also, because the electrode gap is small, the leakage current between the electrodes is easy to flow and the non-impact impact on the leakage current or the electrode. When the electrode potential is changed by the effect of unnecessary current, such as the lens performance is deteriorated, and there is a problem such as difficult to manufacture due to the complicated structure, and the practical use is very difficult.

An object of the present invention is to improve the lens performance of the main lens unit and to reduce the spot diameter focused on a predetermined target by a highly practical method in the electron gun for cathode ray tubes.

The electron gun for cathode ray tube of the present invention has at least two electrodes, each of which has a main lens portion having an electron beam and a hole, and at least a portion of which is located between these electrodes, and at least one having a hole larger than the electron beam and hole of these electrodes. A secondary electrode is provided, and the two opposite electrodes are applied with a relatively low potential and a relatively high potential, and a relatively medium potential is applied to the electric auxiliary electrode. As a result, a long focus lens having a substantially long distance between electrodes can be formed to improve lens performance.

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

FIG. 1 is an example of the color water tube electron gun which implemented this invention, FIG. 2 (a) is sectional drawing of the Y-Z axis | shaft of FIG. 1, and FIG. 2 (b) is sectional drawing of X-Z-axis similarly.

In FIGS. 1, 2 (a) and 2 (b), the electron gun 1 has several electrodes which will be described later, and several insulating supports 2 supporting them.

These electrodes are three for generating three electron beams (3a) (3b) (3c) which strike and strike a red, green, and blue phosphor layer (not shown) of the fluorescent surface to be targeted. And arranged in such a manner that the predetermined electron beam through hole portions protrude from the positions of the cathodes 9a, 9b, 9c arranged in a row to house the heaters 6a, 6b, and 6c of the three cathodes. The first grid 11, the second grid 12, the third grid 13, the fourth grid 14, the converging electrode 15, and the electric third grid 13 having an integrated structure. It consists of the auxiliary electrode 16 which has one large hole between the 4th grid 14, and it is planted in the said electrothermal support body 2, and is fixed.

The first grid 11 and the second grid 12 are plate-shaped electrodes disposed close to each other, and the third grid 13 is disposed close to and joined to the second grid 12. The fourth grid 14 is composed of two cup-shaped electrodes 24a and 24b joined to each other at a predetermined distance from the third grid 13. The converging electrode 15 is composed of one cup-shaped electrode 25a welded to the fourth grid 14. The bottom surface and the plate-shaped electrodes of the cup-shaped electrodes of the grid electrodes and the converging electrodes described above, respectively, are provided with three circular electron beam passage hole portions matched to the respective electron beams.

The electron beam passing holes of the first grid 11 and the second grid 12 are relatively small, and the electron beam passing holes 33a and 33b facing the second grid 12 of the third grid 13 are relatively small. 33c is larger, and the electron beam passing holes 43a, 43b, 43c and the electron beam passing holes of the fourth grid 14 that face the fourth grid 14 of the third grid 13 are larger. 34a, 34b, 34c, and 44a, 44b, 44c have the same diameter and are relatively large in diameter, and the electron beam through holes 35a, 35b, 35c of the converging electrode 15 are larger than that. small.

The above-described auxiliary electrode 16 is composed of two cup-shaped electrodes 26a and 26b, and one large track field shape hole 36 and 46 is provided at the bottom thereof. have.

One cup-shaped electrode of the auxiliary electrode 16 is shown in FIG. 6 (a) and the cup-shaped electrode 23b of the third grid 13 is shown in FIG. 6 (b).

As shown in Fig. 6, the diameters of the X-direction DX and the Y-direction DY of the auxiliary electrode are set to be larger than the diameter of the X-direction dx and the Y-direction diameter dy including the three beam passing holes of the third grid, respectively.

That is, DX> dx and DY> dx.

The above-mentioned convergence electrode 15 is attached with a bulb spacer 17 for applying a high voltage of about 25 Kv applied to an anode terminal (not shown).

Such an electron gun is enclosed in a neck 18 of a thin glass cylinder, and a stem pin 19 is disposed under the neck.

The stem pin 19 supports and fixes the electron gun 1, and is capable of supplying grid potentials other than the convergence electrode 15 and the fourth grid 14 from the outside via the step pin 19.

In the above electrode configuration, each electrode potential is as follows, for example.

The cathode 9 is maintained at a cutoff voltage of about 150 V, to which a modulated signal is applied.

The first grid 11 has a ground potential, and the second grid 12 has a voltage of about 700 V. The third grid 13 has a high voltage of about 6.5 Kv and the fourth grid 14 has a positive high voltage of about 25 Kv. The auxiliary electrode 16 is applied with about 16 Kv, which is approximately an intermediate potential between the potential of the third grid 13 and the potential of the fourth grid 14.

In the electron lens having such an electrode structure in the main lens portion, their potential distributions are as shown in Figs. 3 (a) and 3 (b).

FIG. 3 (a) is a diagram corresponding to FIG. 2 (a) and FIG. 3 (b) is a diagram corresponding to FIG. 2 (b), respectively, and shows an equipotential line 20, each of which describes the main lens portion of the electron gun. For the sake of brevity, a simplified electrode structure is shown.

As shown in FIG. 3 (a) and FIG. 3 (b), the portion of the third grid 13 and the fourth grid 14 that determine the diameter of the electronic lens is roughly the same as the hole (dotted line in the drawing). The potential distribution hardly dissipates in the inside), and as shown in FIG. 14, the potential distribution is equivalent to a state in which the two electric electrodes are not affected by the surrounding electric field when the distance between the electrodes is simply increased. As a result, the axial potential distribution becomes quite smooth as shown in FIG. 5, which reduces the electro-optical magnification by this electron lens and also reduces the spherical aberration coefficient. Performance is significantly improved.

As shown in FIG. 4, simply increasing the distance between electrodes of two electrodes is not practical because the potential distribution is disturbed under the influence of another electric field in the neck as described above. At least one auxiliary electrode with a diameter significantly larger than the lens aperture is disposed between the two electrodes, applying an electric potential approximately midway between the two electrode potentials to the auxiliary electrode, thereby shielding other unnecessary electric fields in the neck and The electric field of the electron lens portion can be prevented from being disturbed.

Therefore, as shown in FIG. 4, it is possible to form a high-performance electron lens equivalent to a case where the distance between two electrodes is simply increased. At this time, the hole of the auxiliary electrode should be one large hole, and like the other electrode, since three electron beam through holes are not necessary, the three hole parts can be enlarged by increasing the distance between the electrodes without changing the distance between the centers. It can easily improve the performance of the electron lens.

In the above embodiment, in order to completely remove the influence of the auxiliary electrode potential, as the electrode gap between the third grid and the fourth grid increases, the hole diameter of the auxiliary electrode does not become larger than that of the third grid and the fourth grid. Can not be done. If the hole diameter of the auxiliary electrode is not sufficient, the electric field of the electron lens formed between the third grid and the fourth grid is disturbed, and the beam spot on the target is crushed.

Distortion of this beam spot can be corrected as the potential of the auxiliary electrode, the hole shape, and the position of the auxiliary electrode.

For example, if the hole diameter of the auxiliary electrode is not large enough in the track feed shape, a kind of quadrupole (between the third grid having a circular hole and the track feed shape auxiliary electrode and similarly between the fourth grid and the auxiliary electrode) A lens is formed, and since the direction of lens action of the two quadrupole lenses is opposite, the direction in which the beam spot is crushed according to the potential of the auxiliary electrode changes.

In other words, when the auxiliary electrode potential is low, the beam length becomes a horizontal beam spot, and when the auxiliary electrode potential is high, the beam length becomes a vertical beam spot.

This suitable potential is a potential that is slightly lower than the potential between the third and fourth grid potentials.

This is because even though the two quadrupole lenses described above have the lens action in the opposite direction, the lens force acting on the beam is different because the beam speed and the beam diameter in the lens are different.

In addition, the same effect as the method of adjusting the auxiliary electrode potential may be achieved by changing the hole shape on the third grid side and the hole shape on the fourth grid side of the auxiliary electrode, or the position of the auxiliary electrode, that is, the third grid and the auxiliary electrode. It is also possible to adjust the spacing between the fourth grid and the auxiliary electrode.

Of course, distortion of the beam may be corrected in the electron lens portions other than the auxiliary electrode.

For example, the electron beam forming unit may have astigmatism beforehand and the auxiliaries may be canceled out.

In the color water tube electron gun of the above embodiment, three electron beams must be converged at one point on a shadow mask or a screen (target), but several methods are known to do this.

That is, a method of tilting and placing both electron guns themselves, a method of tilting both main lenses or other electron lenses, a method of forming an asymmetric lens, and the like.

Also in the present invention, the conventional method of such things can be used as it is, but in the present invention, the above-described convergence can also be achieved by the structure of the auxiliary electrode.

That is, as shown in Fig. 7 (a) and Fig. 7 (b), the electron beams on both sides are made smaller by making the diameter of the X direction DX4 on the fourth grid side of the auxiliary electrode smaller than the diameter of the DX direction on the third grid DX3. Convergence is achieved by slightly deflecting toward the center electron beam.

This is because the potential of the auxiliary electrode on the fourth grid side invades the electron lens portion largely from the potential of the auxiliary electrode on the third grid side in the XZ axis cross section, so that the potential is lower than the average potential at that position. The beams 3a and 3c are forced inwardly.

Alternatively, as shown in FIG. 8 (a) and FIG. 8 (b), two auxiliary electrodes 16-1 and 16-2 are used to form the third grid 13 potential and the fourth grid. (14) Although approximately mid potential of the potential is applied, the potential of the auxiliary electrode 16-2 on the fourth grid side is slightly lower than the potential of the auxiliary electrode 16-1 on the third grid side. As for the same reason, the aforementioned convergence can be achieved.

At this time, the lengths of the electrodes of the two auxiliary electrodes may be adjusted as appropriate.

7 (a) and 8 (a) show the Y-Z axis cross section as shown in FIG. 2, and FIGS. 7 (b) and 8 (b) show the X-Z axis cross section, respectively.

In the above embodiment, the potential of the auxiliary electrode is supplied from the outside through the stem pin, but the present invention is not limited to this, and may be supplied by resistance division.

For example, as shown in FIG. 9, a resistor 54 coated with glass 53 having a resistor 51 and a connection portion 52 disposed on a ceramic substrate 50 having a thin plate phenomenon, as shown in FIG. It is installed behind the insulating support 2 supporting each electrode of the electron gun 1, and one of the resistors is connected to the converging electrode 15 or the fourth grid 14 to apply the positive electrode high voltage Eb, The stem pin 19 is connected to the ground voltage 55 or the low voltage source 56 or the resistor 57 from the outside, and an appropriate position is connected to the auxiliary electrode.

In such a configuration, as shown in FIG. 1, the divided voltage is supplied to the auxiliary electrode by the resistor of the positive electrode high voltage Eb.

Such a resistor 54 is preferably one mainly composed of palladium, ruthenium oxide, or the like, and particularly, a mixture of ruthenium oxide and glass is suitable.

In the embodiment shown in FIG. 10, the resistor is formed in the shape of one plate and is provided behind the insulating support 2. However, the present invention is not limited to this, but the resistor is divided into two parts and used in the auxiliary electrode portion. Needless to say, the application of a resistor directly behind the insulating support, or the use of the insulating support itself as a resistor is within the scope of the present invention.

In the embodiment shown in FIG. 10, one of the resistors is connected to the stem pin. However, the present invention is not limited to this, and may be connected to another grid such as a third grid. Needless to say, it may be supplied.

As described above, by supplying the auxiliary electrode potential by resistance division, there is no need to supply the auxiliary electrode potential of the medium pressure in the stem portion, and the breakdown voltage reliability around the stem portion is improved, thereby providing a practical cathode ray tube. can do.

In addition, supplying even the third grid potential by resistance division further improves the breakdown voltage reliability around the stem portion, and can control the low potential through the stem pin to dynamically control the electronic lens. It is easy to adjust the focusing state.

In addition, dropping the anode high voltage to approximately ground voltage through the high resistor can greatly reduce unnecessary spark currents generated in the water pipe, and can significantly reduce the influence on the water pipe operation circuit. In addition, the IC can protect the IC from spark current in the water pipe.

The electron gun structure of this embodiment is completely different from the structure shown in the US Patent No. 3,932,786.

In other words, the resistor can be made quite large, it is easy to attach to the electrode, it is very easy to manufacture, and because the electrode is wide, the leakage current between the electrodes is difficult to flow, and also the longitudinal and transverse directions of convergence and beam The focusing force adjustment and the beam shape distortion can be easily performed according to the structure of the auxiliary electrode.

Also, it is not necessary to have multiple electrodes and multiple potentials to be supplied thereto, such as the electron gun shown in US Pat. No. 3,932,786, and US Patent No. 3,932,786 as one electrode and potential as in the electron gun of US Pat. Lens performance equivalent to that of the electron gun shown in Fig. 2 can be obtained. Therefore, the resistance splitting voltage is not necessarily required, and since it has many advantages such as being able to obtain a single used voltage through the stem pin, the electron gun of the present invention is very practical as an electron gun having a high performance electron lens.

In addition, in the above embodiment, the auxiliary electrode is disposed while maintaining a predetermined interval between the third grid and the fourth grid, but the present invention is not limited thereto, and as shown in FIG. The effect of the present invention does not change even if it is covered on one or both sides of the four grids.

As shown in FIG. 13, when the auxiliary electrode covers both electrodes, it is possible to completely shield the influence of the unnecessary electric field of the inner wall of the neck. By means of this, it is possible to provide a color receiving tube having excellent performance to completely prevent changes over time.

In addition, in the main lens part of the above-described embodiment, a bipotential lens composed of two electrodes of the third and fourth grids is used, and an auxiliary electrode having a large hole is disposed between the electrodes. The invention is not limited to this, and may be based on a unipotential lens as shown in Fig. 14 (a), and a quadra potential lens as shown in Fig. 14 (b). May be used as the basis, or may be based on a periodic potential lens as shown in FIG. 14 (c), and the nature of the present invention does not change even when the other tripotential lens is used as a basis. .

14 (a) to 14 (c) show an alternative configuration of the main lens portion, and the present invention is applied to all the auxiliary electrodes at the portions forming the electron lens, but the main electron lens is applied. It goes without saying that the present invention may be applied only to a part.

In particular, in the lens system shown in Fig. 14 (b) and Fig. 14 (c), the voltage of the third grid G3 can be set to about 8-9 Kv, so the electron beam from the water spot forming portion is formed. Quality can be used in the best condition, and the performance of the gun is even better.

In the above embodiment, the three electron guns are integrated in a row in the horizontal direction. However, the present invention is not limited thereto, but the three electron guns are arranged in an equilateral triangle. Needless to say, the present invention can be applied to the structure of the arrangement or to the structure of one electron gun.

According to the present invention as described above, at least two electrodes each having an electron beam through hole and at least a portion thereof are located between these electrodes, and at least those having a hole larger than the electron beam through hole of these electrodes. It is provided with one auxiliary electrode, and the lower and relatively high potentials are applied to the two opposing electrodes described above, so that the above-mentioned auxiliary electrode has a relatively middle potential applied thereto. Substantially long long focal length lenses can be formed without problems in practical use.

The electron gun of the present invention is simple in structure and easy to manufacture, and can provide a high-performance cathode ray gun for practical use.

In addition, in the electron gun of the present invention, a high-performance electron gun can be obtained without increasing the distance between the multiple electron beams, that is, the distance between the electron beam through-holes. It can be used as.

Claims (5)

A cathode ray tube electron gun comprising at least an electron beam generating portion and a main lens portion for focusing the electron beam on a predetermined target, wherein the above-mentioned main lens portion is at least two opposite electrodes and at least a portion each having an electron beam passing hole; And having at least one auxiliary electrode positioned between these electrodes and having a larger hole than the electron beam passing hole of the electrodes. The two opposite electrodes described above have a relatively low potential and a relatively high potential. An electron gun for a cathode ray tube, characterized in that the auxiliary electrode is applied to the electrode group to which a relatively medium potential is applied. The method of claim 1, wherein the relatively middle potential applied to the at least one auxiliary electrode described above is divided by a resistor disposed in the vicinity of the above-described main lens portion from the relatively high potential applied to the main lens portion. Electron gun for cathode ray tube, characterized in that the divided resistance potential. The method of claim 1, wherein each of the opposing surfaces of the at least two opposing electrodes disposed on the main lens portion has a plurality of holes corresponding to the electron beams for passing a plurality of electron beams. A hole is an electron gun for cathode ray tubes, characterized in that one hole includes a sufficient number of these holes. The method of claim 1, wherein each of the opposing surfaces of the at least two opposing electrodes disposed on the main lens portion has a plurality of holes corresponding to the electron beams for passing a plurality of electron beams. The hole is a hole containing a sufficient number of these holes, the cathode ray characterized in that the hole diameter in at least one direction of the electron beam incidence side and the outgoing side of the at least one auxiliary electrode hole is different. Tolerance gun. The hole of the auxiliary electrode according to claim 1, wherein each of the opposing surfaces of the at least two opposing electrodes disposed in the main lens portion described above has a plurality of holes corresponding to the electron beams for passing several electron beams. Is a hole containing a sufficient number of these holes, wherein the shape of the holes on the electron beam incidence side and the outgoing side of the holes of the at least one auxiliary electrode is different.

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