JPH0668957B2 - Electron gun structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an electron gun assembly that emits a plurality of beams,
In particular, the present invention relates to an electron gun structure suitable for a three-electron gun structure of a color picture tube.

(Prior Art) As shown in FIG. 8, a color picture tube has an envelope (3) composed of a panel (1) and a funnel (2).
(1) A phosphor screen (4) consisting of a three-color phosphor layer is formed on the inner surface,
A shadow mask (5) is arranged inside the crocodile to face the phosphor screen (4). Also the neck of the funnel (2)
An electron gun assembly (7) that emits three electron beams is arranged in (6), and the three electron beams are transmitted through a shadow mask (5).
The phosphor screen (4)
It is configured to display an image on top.

In such a color picture tube, in order to improve the image on the phosphor screen (4), each electron beam is focused well, the spot diameter of the electron beam on the phosphor screen (4) is reduced, and, It is necessary to properly focus the three electron beams on the phosphor screen (4).

By the way, the electron gun assembly (7) of the color picture tube emits an electron beam, and is emitted from the electron beam generating part including a plurality of electrodes for controlling the generation of the electron beam and the electron beam generating part. Focus the electron beam, accelerate it,
In addition, the main lens portion is composed of a plurality of electrodes that are concentrated on the fluorescent screen (4). Usually, this main lens portion constitutes an electrostatic lens, and there are several types depending on the shape, arrangement, difference in applied voltage of the electrodes, etc., but in order to improve the lens performance in any of them, Is
It is necessary to make the aperture diameter of the electrodes large to make a large-diameter lens, or make the electrode interval large to make a long-focus lens with a gentle potential gradient between the electrodes.

However, since the electron gun assembly (7) is used by being enclosed in the neck (6) which is thinner than the other parts of the envelope (3), there is a limitation in increasing the diameter of the electrode. Further, if the diameter of the electrode is made sufficiently large and the neck (6) is made thick so that it can be enclosed, the power consumption of the deflecting device for deflecting the electron beam increases. In addition, if the electrode spacing of the main lens portion is increased, it becomes easier to be affected by the electric field between the adjacent electrodes and the undesired electric field from the neck (6), and the trajectory of the electron beam changes, so the length is unlimited. It is not possible. In addition, the picture tube becomes longer.

Therefore, conventionally, an electron gun assembly has been developed that solves the above problems. An example is the electron gun structure disclosed in Japanese Examined Patent Publication No. 55-48674. This electron gun assembly is a bipotential type electron gun, and as shown in FIG. 9, a main lens part (9) is sequentially arranged in the electron beam emission direction from the electron beam generation part (10). 1, the second focusing electrode (11),
(12) and a plurality of intermediate electrodes (13) to (18) arranged between these electrodes (11) and (12). A resistor (19) is arranged on one side of the main lens part (9), the second focusing electrode (12) is connected to one end of the resistor (19), and the second focusing electrode (11) is connected to the other end of the resistor. Further, the intermediate electrodes (13) to (18) are connected in the middle thereof.

In this electron gun assembly, when an anode voltage is applied to the second focusing electrode (12), the first focusing electrode (11) and each intermediate electrode (13)
A predetermined voltage divided by the resistor (19) is applied to the electrodes (18) to (18), and the intermediate electrodes (13) to (18) intervene between the first focusing electrode (11) and the second focusing electrode (11). An electric field having a gentle potential gradient is formed in the (12) direction, whereby the electrostatic lens between the first and second focusing electrodes (11) and (12) can be substantially a long focus lens.

However, in this electron gun assembly, the anode voltage applied to the second focusing electrode (12) is divided by the resistor (19) to generate the first focusing electrode.
When the voltage of the first focusing electrode (11) is changed in order to apply it to (11) and each of the intermediate electrodes (13) to (18), the potentials of the intermediate electrodes (13) to (18) also change. As described later, there is a problem that the concentration of the three electron beams changes.

In general, the concentration of the three electron beams is explained by referring to a bipotential type in-line type three electron gun structure which emits a central beam and a pair of side beams arranged in parallel on the same plane. As shown in FIG. Double-sided electron gun with respect to the central axis (21) of the three-electron gun structure that passes through the center of (20G)
The facing surfaces of the first and second focusing electrodes (11) and (12) of (20B) and (20R) are tilted, and the first and second focusing electrodes (11) and (12) of the central electron gun (20G) are tilted.
For the electrostatic lens (22G) formed between (12), the electrostatic formed between the first and second focusing electrodes (11), (12) of the double-sided electron guns (20B), (20R). It is obtained by inclining the lenses (22B) and (22R) so that both sides advance in the electron beam emission direction. That is, the pair of side beams (23B) and (23R) are moved by the electrostatic lens (22B) and (22R) to the central electron gun (20
The orbit changes in the direction intersecting with the central beam (23G) that passes over the center of G) and is subjected to the concentration effect.

The concentration of the three electron beams (23B), (23G), (23R) is
As shown in the figure, the central axis (24) of the second focusing electrode (12) of the double-sided electron guns (20B), (20R) (only one of the electron guns (20B) is shown in the drawing) is connected to the first focusing electrode ( It can also be performed by making the center axis (25) of 11) eccentric in a direction away from the center axis (21) of the three-electron gun assembly. In this case, both focusing electrodes (11), (1
The electrostatic lens shown by the equipotential curve (26) is formed between 2),
Similar to the electron gun assembly shown in FIG. 10, the three electron beams are focused.

By the way, Japanese Patent Publication No. 55-48674 does not disclose a concrete concentrating means for the electron gun assembly shown in FIG. 9, but the three electron beams emitted from this electron gun assembly are used as fluorescent screens. (4) In order to concentrate on the above, one of the above-mentioned concentration means must be used. Assuming that the latter concentrating means shown in FIG. 11 is adopted, in order to change the voltage of the first focusing electrode (11) in order to obtain optimum focusing, the second focusing electrode (12) The anode voltage applied to each intermediate electrode must be changed accordingly.
The voltages of (13) to (18) also change, the concentration of the three electron beams changes, and a predetermined concentration cannot be obtained.

As an electron gun structure that solves such problems, Japanese Patent Publication No. 55-5
3853 discloses an electron gun assembly shown in FIG. This electron gun assembly is a quadra-potential type electron gun, and is composed of third to sixth grids (2
8) to (31), which are connected so as to apply the same voltage to the third and fifth grids (28) and (30), and are connected to the third to fifth grids.
Electrostatic lenses (32) and (33) are formed between (28) to (30) and the fifth and sixth grids (30) and (31), respectively. Also, in this electron gun assembly, the fifth and sixth grids (30), (31) of the pair of double-sided electron guns (20B), (20R) (only one electron gun (20B) is shown in the drawing) are sequentially arranged. It is eccentric in the direction away from the central axis (21) of the electron gun assembly.
And, for example, about 7K on the 3rd and 5th grids (28), (30)
V, about 600V on the 4th grid (29), about 2 on the 6th grid (31)
It is used by applying a voltage of 5KV.

If the three-electron gun assembly is constructed as described above, for example, if the focusing voltage applied to the third and fifth grids (28) and (30) is increased, the electrostatic lens (32) has a strong lens action. Then, the orbits of the pair of side beams (23B) and (23R) (only one of the side beams (23B) is shown) are changed so that they are closer to the central beam (23G). On the contrary, the action is weakened, and as a result, the concentration of the three electron beams cannot be changed. Further, if the focusing voltage applied to the third and fifth grids (28) and (30) is lowered, it is possible to prevent the concentration of the three electron beams from changing due to the lens action opposite to the above. Therefore, in this electron gun structure, the focusing of each electron beam can be adjusted by changing the voltage of the third and fifth grids (28) and (30) without changing the concentration of the three electron beams. .

However, in this electron gun assembly, the side beam passes twice through the electrically distorted electrostatic lenses (32) and (33) formed by decentering the electrodes, so that the side beam is greatly distorted. Easy and therefore central beam (23G)
And the focusing state of the pair of side beams is not uniform, which deteriorates the focusing characteristics of the electron gun assembly.

In addition, Japanese Patent Application No. 60-274958, Japanese Patent Application Laid-Open No. 62-13
No. 6738), as shown in FIG. 13, the main lens portion, focusing electrode (35), acceleration electrode (36) and these electrodes (35), (36)
One intermediate electrode (37) is arranged between them, and a resistor (19) is arranged outside the main lens part, and one end of the resistor (19) is applied with a high voltage (anode voltage) 36) with the other end grounded. In this electron gun structure, a low voltage is independently applied to the focusing electrode (35) without going through the resistor (19), and the intermediate electrode (37) is connected to the middle of the resistor (19). A predetermined medium voltage divided by the resistor (19) is applied. Also, a pair of double-sided electron guns (20B), (20R) of this electron gun structure (in the drawing
Only (20B) is eccentric to the accelerating electrode (36) with respect to the intermediate electrode (37) in a direction away from the central axis (21) of the electron gun assembly.

By the way, when the electron gun assembly is configured in this way, a voltage is applied to the focusing electrode (35) independently of the other electrodes (36) and (37), so that the voltage of the focusing electrode (35) is theoretically applied. Even if is changed, the potentials of the other electrodes (36) and (37) do not change, and it is possible to make the concentration of the three electron beams hardly change. However, in this electron gun structure, when electrons are emitted from the branch point (38) of the resistor (19) to the high voltage side for some reason, the potential at this branch point (38) rises higher than in the normal case. , The potential difference between the intermediate electrode (37) and the accelerating electrode (36) becomes small, and the leak current flows into the branch point (38), which causes the electrostatic lens between these electrodes (36) and (37). The action of may weaken and the concentration of the three electron beams may change.

Note that US Pat. No. 2,859,378 shows a focusing means using a plurality of plate-shaped electrodes. The plurality of plate-shaped electrodes are multi-staged eccentric, and a voltage divided by a resistor arranged outside the envelope is applied. However, the eccentricity of the plurality of plate-shaped electrodes of this electron gun assembly is in the direction of approaching the central axis of the electron gun assembly, and the pair of side beams is concentrated by a concentrating means other than this concentrating means.
It is different from the electron gun assembly of the present invention described later.

(Problems to be Solved by the Invention) As described above, in the color picture tube, in order to display a good image on the phosphor screen, the focusing and concentration of the three electron beams emitted from the electron gun assembly should be good. Need to For that purpose, the aperture diameter of the electrode of the electron gun structure may be increased to form a large-diameter lens, or the electrode interval may be increased to form a long-focus lens, but simply increase the aperture diameter of the electrode, If the electrode spacing is increased, other inconvenient problems will occur. Therefore, various improved electron gun assemblies have been developed, but when the focusing voltage is changed, these electron gun assemblies have different focusing properties due to electron beam concentration or electron beam distortion. There are problems such as deterioration and concentration change easily due to other causes, and there is no perfect one yet.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electron gun assembly that emits a plurality of beams and that improves the focusing and concentration of the electron beams.

[Structure of Invention]

(Means for Solving the Problems) An electron beam generator that emits a plurality of beams, and a low voltage and a high voltage that are sequentially applied to the electron beam generator in the electron beam emission direction. A main lens portion composed of first and second electrodes and a plurality of intermediate electrodes positioned between these electrodes and to which a medium voltage is applied;
Of the intermediate voltage applying means connected to the electrode of the second electrode and the other end of which is grounded, and the intermediate electrode is connected in the middle, and a low voltage is applied to the first voltage independently of the intermediate voltage applying means. In an electron gun assembly having a low voltage applying means for applying, a plurality of intermediate electrodes of the main lens section are provided at two positions between an intermediate electrode and a second electrode adjacent to the first electrode, or between the intermediate electrodes. The eccentricity or the facing surface is inclined with respect to the adjacent electrode at any one position.

(Operation) As described above, a plurality of intermediate electrodes to which the medium voltage is applied are arranged between the first electrode to which the low voltage is applied and the second electrode to which the high voltage is applied, and the intermediate electrode A voltage applying means for the first electrode is provided independently of the voltage applying means for the electrode, and a plurality of intermediate electrodes thereof are provided at two locations between the intermediate electrode and the second electrode adjacent to the first electrode or the plurality of the intermediate electrodes. If the eccentricity or the facing surface is inclined with respect to the adjacent electrode at any one position between the intermediate electrodes, the main lens portion can be a long focus lens having good focusing characteristics, and the focusing of the first electrode can be performed. Even if the voltage is changed, the concentration of the electron beam can be hardly affected. Further, even if a leak current is generated in the resistor for some reason, the concentration of the electron beam can be prevented from being affected.

(Embodiment) Hereinafter, the present invention will be described based on an embodiment with reference to the drawings.

FIG. 1 schematically shows an electron gun assembly of a color picture tube which is an embodiment of the present invention, FIG. 2 schematically shows the electrical connection of its electrodes, and FIG. 3 schematically shows its main lens portion. This electron gun assembly is a bi-potential type in-line type three electron gun assembly, and includes a cathode section (40) and first, second grids (41), (1) arranged sequentially on the cathode section (40). 42), and a main lens section composed of a plurality of electrodes sequentially arranged on the second grid (42). In particular, the main lens portion of the electron gun assembly is provided on the third grid (43) adjacent to the second grid (42), and the fourth and fifth grids (4) which are usually called intermediate electrodes or auxiliary electrodes.
It is configured by arranging a sixth grid (46) via 4) and (45). Moreover, in this electron gun assembly, the electrodes of the pair of double-sided electron guns are located at two positions between the fourth grid (44) and the sixth grid (46) adjacent to the third grid (43), that is, the fourth grid (44). , Between the fifth grids (44) and (45) and between the fifth and sixth grids (45) and (46), the fifth and sixth grids (45) and (46) are the central axes of the electron gun assembly ( It is eccentric in the direction away from 21). And each of the electrodes (40) ~
(46) is integrally fixed by a pair of insulating supports (47).

Of the electrodes (40) to (46), the cathode part (40) has three cathodes (49) arranged in a row and each having a heater (48) installed therein.
The first to sixth grids (41) to (46) sequentially arranged on the cathode part (40) are respectively composed of the three cathodes (4).
It is formed as an integrated structure (unitize structure) having three electron beam passage holes corresponding to 9). That is, the first grid (41) adjacent to the cathode part (40) and the second grid (42) adjacent to the first grid (41) are formed in a flat plate shape, and are sequentially arranged on the second grid (42). Each of the arranged third to sixth grids (43) to (46) is formed by abutting two cup-shaped electrodes. Especially in this electrode structure, the fourth and fifth grids (44), (45) as intermediate electrodes
With regard to the above, it may be configured by abutting two cup-shaped electrodes through a perforated plate having a relatively large plate thickness. The sixth cup (46) has a convergence cup.
(50) fixed together, this convergence cup (50)
When this electron gun structure is installed in the neck (6),
The sixth grid (46) of the electron gun structure is supported by pressure contact with the inner surface of the neck (6) and a high voltage (anode voltage) of about 20 to 30 KV applied to the anode terminal is applied to the internal conductive film ( Five
A plurality of valve spacers (52) are attached which communicate to the convergence cup (50) and the sixth grid via 1).

A plate-shaped resistor (54) is attached to the back surface of one of the pair of insulating supports (47). One end of the resistor (54) is the sixth grid (46) (or the convergence cup (5) to which the high voltage is applied.
0)) and the other end is grounded directly through one of the plurality of stem pins (55) or through a circuit component such as a capacitor or a resistor, and the fourth and fifth grids are in between. (44) and (45) are connected. Then, by dividing the high voltage applied to the one end, the fourth and fifth grids (4
It is designed to be applied to 4) and (45).

In addition, the sixth grid (46) and the fourth and fifth grids
The electrodes other than (44) and (45) are respectively connected to the stem pin (55), and particularly for the third grid (43), a variable resistor (56) is installed via the stem pin (55) for adjusting the focus. ) Is connected.

In the electron gun assembly having such a configuration, the following voltages are applied to each electrode, for example. That is, the cathode (49)
A cut-off voltage of about 150 V is applied to and a modulation signal is applied to it. The first grid (41) is grounded like the other end of the resistor (54), and the second grid (42) has about 700V,
About 6-8KV on the 3rd grid (43), about 25KV on the 6th grid (46) via the convergence cup (50) integrated with it.
High voltage (anode voltage) is applied. The fourth and fifth grids (44) and (45), which are intermediate electrodes, are connected to the anode voltage of the resistor (54) as an intermediate voltage of the third and sixth grids (43) and (46), respectively. A voltage of about 14 KV and 18 KV, which is the divided voltage, is applied.

By the way, when the main lens unit is configured as described above, the electric field with a gentle potential gradient from the third grid (43) to the sixth grid (46) is formed by the interposition of the fourth and fifth grids (44) and (45). Can be formed into an electrostatic lens having a substantially long focal length, whereby spherical aberration can be reduced and lens performance can be improved.

Further, in this electron gun assembly, the fourth and fifth grids (44), (45) are electrically independent of the third grid (43) which is the focusing electrode, so the third grid (43) Even if the focusing voltage is changed, the potentials of the fourth and fifth grids (44) and (45) do not change, and therefore, the concentration action of the pair of double-sided electron guns hardly changes.

In addition, in this electron gun structure, the fifth
Even if the voltage of the grid (45) changes, as shown in FIG. 3, the resistance between the fifth and sixth grids (45), (46) of the resistor (54) is changed to R ₁ , the fourth, the fourth. The resistance between the 5 grids (44) and (45) is R ₂ ,
When the resistance from the fourth grid (44) to the other end of the resistor (54) is R ₃ , the voltage of the fourth grid (44) is It is given by the 4th grid (44) and the 5th grid (4
The voltage ratio of 5) does not change, and therefore does not change the concentration of the pair of double-sided electron guns with respect to the electron beam. When the voltage of the fifth grid (45) changes, the fifth grid (45)
And the voltage ratio of the 6th grid (46) changes, but in this case,
As shown in FIGS. 4 (A) to 4 (C), the curvature of the equipotential curve (58) also changes with the change of the voltage ratio, and the change of the curvature with respect to the concentration of the electron beam The voltage ratio between the fifth and sixth grids (45) and (46) acts in the opposite manner, so that the concentration is hardly changed. The fourth
In the figure, (A) shows (B) and (B) when the voltage ratio is normal.
Figure (C) shows the case where the voltage ratio changes due to the leakage current.

Further, in this electron gun structure, the electrodes are eccentric at two locations. Since the eccentricities at these two locations are performed at close positions, the side beam distortion due to the two-stage eccentricity is different from that in the case of one-stage eccentricity. It can be suppressed to the same level.

Further, in this electron gun structure, the fourth to sixth grids are used.
Since (44) to (46) are electrically connected via the resistor (54), the total resistance value of this resistor (54) is, for example, 500 MΩ to 5 G.
By increasing it to Ω, compared with the conventional electron gun structure having a main lens section composed of simply arranged electrodes,
Arc discharge between the electrodes can be suppressed almost completely. Further, even if arc discharge occurs between the electrodes, the current flowing through the image receiving circuit through the stem pin (55) can be reduced. That is, in the conventional electron gun assembly, when arc discharge occurs, a large current of about 500 to 1000 A flows, but in this electron gun assembly, it can be set to several μA to several A, and the image receiving circuit The impact on it can be reduced.
Therefore, by using this electron gun structure, it is possible to omit the circuit elements such as the inductance, the capacitor, and the resistor for protecting the circuit from the inrush current accompanying the arc discharge which is currently adopted in most image receiving circuits. It is possible to simplify the receiver and improve its reliability.

Next, another embodiment will be described.

FIG. 5 shows an example applied to a quadra-potential type electron gun. In this case, the intermediate electrode is the fifth and sixth grids (6
It is located between 0) and (61). In the illustrated example, the intermediate electrode is composed of two electrodes (62) and (63), one electrode (62) adjacent to the fifth grid (60) and the other electrode (63), and the other electrode. Between the electrode (63) and the sixth grid (61) of the
At the points, the electrode (63) and the sixth grid (61) are eccentric in the direction away from the central axis of the electron gun assembly.

These electrodes (62) and (63) are connected at one end to the sixth grid (61) to which a high voltage (anode voltage) is applied, and at the other end to the middle of the grounded resistor (54). Has been done. The fifth grid (60) is connected to an externally installed variable resistor (56) via a stem pin (not shown). In FIG. 5, (49) is the cathode, (41) is the first grid,
(42) is the 2nd grid, (43) is the 3rd grid, (44) is the 4th grid
It is a grid.

If the quadra-potential type electron gun is configured as described above, unlike the conventional quadra-pontential type electron gun, even if the focusing voltage applied to the fifth grid (60) is changed,
As in the above-mentioned embodiment, the concentration of the three electron beams can be made completely unchanged. Further, even if the potential of the electrode (63) which is the intermediate electrode changes for some reason, the concentration of the three electron beams can be made almost unchanged.

FIG. 6 shows, in the bipotential type electron gun, between the third and sixth grids (43) and (46) constituting the main lens portion, as in the first embodiment, the fourth and the fourth intermediate electrodes are provided. 5 grids (44) and (45) are arranged. Especially, in the electron gun assembly of this example, the electrodes of the pair of double-sided electron guns are located between the fourth and fifth grids (44) and (45). The central axis (2
It is eccentric in the direction away from 1). The fourth and fifth grids (44) and (45) are connected to the sixth grid (46) to which a high voltage is applied at one end and to the middle of the resistor (54) whose other end is grounded. Has been done. In addition, the third grid (4
3) is connected to an externally installed variable resistor (56) via a stem pin (not shown).

When the electron gun assembly is constructed in this way, not only the same effects as those of the first embodiment are obtained, but also the eccentricity of the electrode is performed only at one location, so that the side eccentricity is reduced compared to the case of the two-stage eccentricity. The beam distortion is small and the three electron beams can be well focused.

FIG. 7 corresponds to the quadra-potential type electron gun shown in FIG. 5, in particular, two electrodes (62) as an intermediate electrode between the fifth and sixth grids (60) and (61). , (63),
The electrode (63) is eccentric between the two electrodes (62) and (63) in a direction away from the central axis (21) of the electron gun assembly.

Also in this electron gun structure, the concentration of three electron beams can be made completely unchanged, and the electrode (63) which is an intermediate electrode
Even if the electric potential of 3 changes due to some cause, the concentration of the three electron beams can be kept unchanged.

Next, a specific example of the electron gun assembly shown in the above embodiment will be described.

A bipotential in-line type electron gun assembly having an opening diameter of the main lens portion of 6.2 mm, a distance of 6.6 mm between the central axis of the electron gun assembly and the opening axes of the pair of double-sided electron guns is set at the center of the main lens portion. Mounted in the neck of the color picture tube so that the distance from the screen is 390 mm, and the voltage applied to the 6th grid of this electron gun assembly is 100%, and the 3rd, 4th, 5th
When 28%, 40%, and 65% of the voltage is applied to the grid, the electrode is 0.33 mm between the 5th and 6th grids of the double-sided electron gun.
The conventional eccentric electron gun assembly has a leakage current of 4μ.
A When flowing, the concentration of 3 electron beams is about 6-8 mm on the screen.
This invention has changed, but the fifth grid is eccentric to the fourth grid between the fourth and fifth grids by 0.25 mm, and the sixth grid is eccentric to the fifth grid between the fifth and sixth grids by 0.08 mm. In the electron gun assembly of, when the leak current is 4 μA,
The change in the concentration of the three electron beams on the screen could be reduced to 0.5 mm or less.

The performance is 30 to 30 times that of the voltage applied to the sixth grid, which is the voltage applied to the fourth grid adjacent to the third grid.
80%, the voltage applied to the fifth grid is 50% to 80% of the voltage applied to the sixth grid, and
The eccentricity of the grid and the eccentricity of the sixth grid with respect to the fifth grid are 16 × 10 ⁻³ to 80 × 10 ⁻³ and 6 × 10 ⁻³ to the opening diameter of the electrode of the main lens portion, respectively.
Almost the same result can be obtained by changing the range of 33 × 10 ⁻³ .

In the same bi-potential type in-line type electron gun structure, as in the above specific example, the voltage applied to the sixth grid is set to 100%, and 28% and 40% are applied to the third, fourth and fifth grids, respectively. %, 65% voltage applied, even in the electron gun structure in which the fifth grid is eccentric to the fourth grid between the fourth and fifth grids on both sides of the electron gun by 0.33 mm, when the leakage current is 4 μA, The change in the concentration of the three electron beams on the screen could be reduced to about 0.5 mm or less. In addition, such performance is 30-80% of the voltage applied to the sixth grid, which is the voltage applied to the fourth grid adjacent to the third grid.
%, The voltage applied to the fifth grid is 50% to 80% of the voltage applied to the sixth grid, and the eccentricity of the fifth grid with respect to the fourth grid is 16 × 1 with respect to the aperture diameter of the main lens.
Almost the same result is obtained even when the range is changed from 0 ⁻³ to 80 × 10 ⁻³ .

In each of the above embodiments, the case where two electrodes are arranged as the intermediate electrodes has been described, but the number of the intermediate electrodes may be two or more.

Further, in each of the above embodiments, the electrode was eccentric as the electron beam concentrating means, but instead of the eccentricity of the electrode,
You may make it concentrate by inclining the opposing surface of an electrode.

Further, the present invention can be applied not only to the bipotential type and quadrapotential type electron guns but also to other types of electron guns such as the unipotential type, and not only the inline type electron gun but also the delta type 3 electron gun. Can also be applied to.

〔The invention's effect〕

For an electron beam generator that emits a plurality of beams, between a first electrode to which a low voltage is applied and a second electrode to which a high voltage is applied, which are sequentially positioned in the electron beam emission direction,
A plurality of intermediate electrodes to which a medium voltage between the high and low voltages applied to these electrodes is applied are arranged to form a main lens unit, one end of which is connected to the above-mentioned intermediate electrode and the above-mentioned second electrode, and A predetermined medium voltage is applied through a medium voltage applying means composed of a resistor whose other end is grounded, and a low voltage is applied to the first electrode independently of the middle voltage applying means by the low voltage applying means. And applying the intermediate electrode to the adjacent electrode at two positions between the intermediate electrode and the second electrode adjacent to the first electrode or at any one position between the plurality of intermediate electrodes. On the other hand, if the eccentricity or the opposing surface is provided so as to be inclined, the main lens portion can be a long-focus lens having good focusing characteristics, and even if the focusing voltage applied to the first electrode is changed, Almost no change in concentration, and some cause Even arc discharge is generated between more electrodes may be an electron gun assembly which has little effect on the concentration of the electron beam. In addition, this electron gun structure can reduce the current flowing in the image receiving circuit even if arc discharge occurs between the electrodes, and omits the circuit element that has been conventionally used for circuit protection. Can be simplified and its reliability can be improved.

[Brief description of drawings]

1 to 7 are explanatory views of an embodiment of the present invention.
FIG. 1 is a configuration diagram of a bipotential type in-line type electron gun which is an embodiment of the present invention, FIG. 2 is a diagram showing electrical connection of its electrodes, and FIG. 3 is a configuration diagram of its main lens portion. 4A to 4C are views showing the relationship between the potential distribution and the equipotential curve of the main lens portion, respectively.
FIG. 6 is a diagram of another embodiment applied to a quadra-potential type electron gun, FIG. 6 is a diagram of another embodiment applied to a bi-potential type electron gun, and FIG. 7 is applied to a quadra-potential type electron gun. FIG. 8 is a schematic view of a color picture tube, FIG. 9 is a schematic view of a conventional improved bipotential type electron gun, and FIG. 10 and FIG. FIG. 12 is a diagram for explaining concentration, FIG. 12 is a configuration diagram of a main lens portion of a conventional quadrapotential type electron gun, and FIG. 13 is a configuration diagram of an electron gun according to a prior application of the present application. (40) …… cathode part, (41) …… first grid (42) …… second grid, (43) …… third grid (44) …… fourth grid, (45) …… fifth grid (46) …… 6th grid, (54) …… resistor (56) …… variable resistance, (60) …… fifth grid (61) …… 6th grid, (62) …… electrode (intermediate electrode) ) (63) …… Electrode (intermediate electrode)

Claims (3)

[Claims] 1. An electron beam generator that emits a plurality of beams, a first electrode sequentially positioned in the electron beam emission direction with respect to the electron beam generator, and a low voltage is applied to the electron beam generator, and the first electrode. A main lens portion comprising a second electrode to which a higher voltage is applied and a plurality of intermediate electrodes which are located between the first and second electrodes and to which a middle voltage between the high and low voltages is applied; Is connected to the second electrode and the other end is grounded, and has a resistor for applying a predetermined intermediate voltage to the intermediate electrode; and the first intermediate voltage applying means independently of the first intermediate voltage applying means. Low voltage applying means for applying a low voltage to the electrodes, wherein the plurality of intermediate electrodes are at two positions between the intermediate electrode adjacent to the first electrode and the second electrode or the plurality of intermediate electrodes. Eccentric to the adjacent electrode at any one point between In addition, the electron gun assembly is characterized in that the facing surfaces are inclined. 2. An adjacent intermediate electrode which is eccentric to the adjacent electrode at two locations is set to have a voltage applied to the intermediate electrode near the first electrode of 30 to 80% of a voltage applied to the second electrode, When the voltage applied to the intermediate electrode near the second electrode is 50% to 80% of the voltage applied to the second electrode, the eccentricity of the main lens portion with respect to the opening diameter of the electrode is 16 × 10 ⁻³ to 80 × 10 at the intermediate electrode near the electrode
^-3 , and 6 at the intermediate electrode near the second electrode.
× ^{10 -3} ~33 × ¹⁰ -3 electron gun assembly of the claims paragraph 1, wherein a is. 3. The first intermediate electrode is eccentric to the adjacent electrode.
The voltage applied to the intermediate electrode close to the second electrode is 30 to 80% of the voltage applied to the second electrode, and the voltage applied to the intermediate electrode close to the second electrode is the same as the voltage applied to the second electrode.
The electron gun assembly according to claim 1, wherein the amount of eccentricity with respect to the opening diameter of the electrode of the main lens portion is 16 × 10 ⁻³ to 80 × 10 ⁻³ when 50% to 80%. .