JPH11307009A - Color cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode ray tube improving a focusing characteristic, by drastically lowering aberration of electron beams of a tripolar part of DF(dynamic focus) method in-line electron guns. SOLUTION: In this color cathode ray tube provided with in-line electron guns 7, the in-line guns 7 are provided with negative electrodes 10, 102 , 103 , a first grid electrode 11, a second grid electrode 12, a first group 13(1) of third grid electrodes, a second group 13(2) of third grid electrodes, and a positive electrode 15. Constant focusing voltage is impressed on the first group 13(1), and variable focusing voltage formed by superposing dynamic voltage on the constant focusing voltage is impressed on the second group 13(2). An electrostatic quadrupole lens is formed between the first group 13(1) and the second group 13(2). And the following formulae are met, G1VR>G2VR, G1HR>G2HR, 0.096<=S1<=0.115, 0.070<=S2<=0.115, where G1VR is a vertical diameter of electron beam passing holes of the first grid electrode 11, G1HR is a horizontal diameter of them, S1 is an area of them, G2VR is a vertical diameter of electron beam passing holes of the second grid electrode 12, G2HR is a horizontal diameter of them, and S2 is an area of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly, to a color cathode ray tube having a dynamic focus type in-line electron gun, having excellent focus performance over the entire display surface, and capable of obtaining good resolution. It relates to a cathode ray tube.

[0002]

2. Description of the Related Art Conventionally, in a color cathode ray tube equipped with an in-line electron gun, a fluorescent surface is attached to an inner surface of a face plate of a panel, a shadow mask is mounted inside the panel so as to face the fluorescent surface, and a funnel is provided. A deflection yoke is mounted on the outer periphery of the unit, and an in-line electron gun is housed in the neck. In this case, the in-line electron gun includes three in-line arranged cathodes, at least a first grid electrode, a second grid electrode, a third grid electrode, and an anode, and projects three electron beams toward the phosphor screen. Let it.

FIG. 6 shows an inline electron gun of the known dynamic focus system (hereinafter referred to as a DF).
FIG. 1 is a cross-sectional view showing a configuration of a color cathode ray tube including a color in-line electron gun).

In FIG. 6, 41 is a panel portion, 41F is a face plate, 42 is a neck portion, 43 is a funnel portion, 44 is a fluorescent screen, 45 is a shadow mask, 46 is an internal conductive film, and 47 is a DF type in-line electronic device. The gun 48 is a deflection yoke.

Further, in the DF mode line electron gun 47, 50 ₁ the left cathode, 50 ₂ is a center cathode, 50 ₃ is right cathode, the first grid electrode 51, the 52 second grid electrode,
53 (1) is a first group of third grid electrodes; 53 (2) is a second group of third grid electrodes; 54 is a fourth grid electrode; 55 is a shield cup (anode); 56 is a vertical electrode piece; It is an electrode piece.

In this case, the glass bulb constituting the color cathode ray tube comprises a panel portion 41, a neck portion 42, and a funnel portion 43. The panel portion 41 has a fluorescent surface 44 formed on the inner surface of the face plate 41F.
A shadow mask 45 is provided at a position facing the fluorescent screen 44 inside.
Is attached. The inner conductive film 46 is formed on the inner surface of the funnel 43, and the deflection yoke 48 is mounted on the outer periphery. The neck portion 42 houses a DF type in-line electron gun 47 therein.

[0007] DF scheme line electron gun 47, the cathodes 50 _1, 50 _2, 50 ₃ are arranged in-line shape in the horizontal direction, along the axial direction of the tube in front of the cathodes 50 _1, 50 _2, 50 ₃ , First grid electrode 51, second grid electrode 52, third grid electrode first group 53 (1), third grid electrode second group 53
(2) The fourth grid electrode 54 and the shield cup 55 are arranged in this order. The fourth grid electrode 54 and the shield cup 55 are connected to each other in the tube axis direction.
The first grid electrode 51, the second grid electrode 52, the third grid electrode first group 53 (1), the third grid electrode second group 53 (2), the fourth grid electrode
Both the grid electrode 54 and the shield cup 55 are located at a position corresponding to the central axis O ₁ of the left cathode 50 ₁ , the center cathode 50.
Position corresponding to the _second center axis O _2, each electron beam apertures at positions corresponding to the central axis O ₃ of the right cathode 50 ₃ are provided.

[0008] In the fourth grid electrode 54, a central electron beam passage hole is provided in a position corresponding to the central axis O ₂ of the cathode 50 ₂ whose center line corresponds to the left and right of the electron beam passage holes, the center the center axis O ₁ of the cathode 50 ₁ the lines corresponding, provided at a position which is slightly displaced outward directions with respect to the central axis O ₃ of the cathode 50 _3. Third grid electrode first
The group 53 (1) is provided with a vertical electrode piece 56 which sandwiches three electron beam passage holes from the vertical direction individually at a position facing the third grid electrode second group 53 (2). The group 53 (2) is provided with a horizontal electrode piece 57 sandwiching the three electron beam passage holes from the horizontal direction in common at a position facing the vertical electrode piece 56. Then, the third grid electrode first group 53
The vertical electrode piece 56 and the horizontal electrode piece 57 provided between (1) and the third grid electrode second group 53 (2) constitute an electrostatic quadrupole lens.

In operation, the first grid electrode 51 is connected to the ground voltage or a negative voltage Vg1 (eg, 0 to-
100 V), and a relatively low positive voltage Vg2 (for example, 400 to 1000 V) is applied to the second grid electrode 52. A constant focusing voltage Vf (for example, 5 to 10 kV) is applied to the first group of third grid electrodes 53 (1).
A focusing voltage (Vf +) in which a dynamic voltage Vd that changes according to the amount of electron beam deflection is superimposed on a constant voltage Vf (for example, 5 to 10 kV) is applied to the second grid electrode group 53 (2).
Vd) is applied. A high anode voltage Vp (for example, 25 to 30 kV) is applied to the fourth grid electrode 54, the shield cup 55, and the internal conductive film 46.

FIG. 7 is an explanatory view showing a focused state of three electron beams in the DF type in-line electron gun 37 shown in FIG.

In FIG. 7, 58 is a heater, 59 is an electron beam, and the same components as those shown in FIG. 6 are denoted by the same reference numerals.

The operation of the known DF type in-line electron gun 37 will be described with reference to FIGS.

By driving the heater 58, each cathode 50 ₁ ,
When 50 ₂ and 50 ₃ are heated, each cathode 50 ₁ , 5
0 _2, 50 ₃ thermoelectrons from are emitted. The emitted thermoelectrons are attracted toward the first grid electrode 51 by the relatively low positive voltage Vg2 applied to the second grid electrode 52,
At the same time, three electron beams 59 are formed.
These three electron beams 59 are applied to the cathodes 50 ₁ , 5
O ₂ , 50 ₃ , a first grid electrode 51, and a second grid electrode 52 are used to form a three-pole lens between the first grid electrode 51 and the second grid electrode 52 or between the second grid electrode 52 and the third grid electrode 53. Crossover between Then these three
The electron beam 59 is diverged while the first grid electrode 51
The light is slightly focused by the pre-focus lens between the first grating electrode 52 and the second grating electrode 52 and is incident on the main lens. The main lens is formed by an electrostatic field caused by a voltage difference between the focusing voltage (Vf + Vd) applied to the third grid electrode second group 53 (2) and the anode voltage Vp applied to the fourth grid electrode 54. The orbits of the three electron beams 59 are bent by the electrostatic field, and each of the three beams 59 is focused.
A focused spot is formed on the phosphor screen 44. At this time, the spots formed on the fluorescent screen 44 are scanned in the horizontal and vertical directions by the deflection magnetic field generated by the deflection yoke 48, and three spots are formed by the shadow mask 45 disposed immediately before the fluorescent screen 44. The electron beam 59 is color-sorted, and irradiates a phosphor of a corresponding color on the fluorescent screen 44 to display a desired image on the fluorescent screen 44.

At this time, the diameter of the spot formed on the fluorescent screen 44 depends on the state of crossover by the three-pole lens,
That depends on the current value of the cathodes 50 _1, 50 _2, 50 _3. Each cathode 50 _1, 50 _2, although the spot diameter is also reduced when 50 small current value of _3, the cathodes 50 _1, 5
0 _2, the current value of 50 ₃ becomes larger when coming spread also spot diameter.

FIG. 8 is a characteristic diagram showing focus characteristics of the in-line electron gun in the color cathode ray tube having the in-line electron gun.

In FIG. 8, the vertical axis represents the electron beam spot diameter Ds formed on the fluorescent screen 44 in mm.
The horizontal axis is the electron beam diameter Dout on the output surface of the main lens expressed in mm. The curve a indicates that each cathode 5
0 _1, 50 _2, the current value of 50 ₃ are characteristic when 0.3 mA, curve b, the current value of the cathodes 50 _1, 50 _2, 50 ₃ are characteristic when 0.1 mA, Curve c is the spherical aberration of the main lens, curve d is the space charge effect, and curve e is the initial thermal velocity dispersion.

As shown in FIG. 8, when the size of the main lens is fixed, the spherical aberration (curve c) of the main lens becomes more remarkable as the electron beam diameter Dout on the output surface of the main lens becomes larger. The spot diameter Ds increases. On the other hand, the space electron effect (curve d) and the thermal initial velocity dispersion (curve e) are obtained by calculating the electron beam diameter Dou at the output surface of the main lens.
The electron beam spot diameter D decreases as t increases.
s is reduced.

The focus characteristics of the in-line electron gun are as follows: the result of combining the spherical aberration (curve c) of the main lens and the space electron effect (curve d) (curve a); and the spherical aberration of the main lens (curve c). Is represented by a composite result (curve b) of the thermal initial velocity dispersion (curve e) and a quadratic function characteristic in any of the focus characteristics, and a certain value of the electron beam diameter Dout on the output surface of the main lens. , An optimum value that minimizes the electron beam spot diameter Ds is obtained.

In this case, the electron beam diameter Dout at the output surface of the main lens is determined by the respective cathodes 50 ₁ , 50 ₂ , 50 ₃ ,
The dimensions of the three-electrode portion including the first grid electrode 51 and the second grid electrode 52, and the electrode of the focusing electrode including the third grid electrode first group 53 (1) and the third grid electrode second group 53 (2) Depends on length etc. In the DF in-line electron gun 47, the spot diameter can be prevented from expanding around the screen due to astigmatism due to the deflection of the electron beam. Therefore, the electron beam diameter Dout is smaller than the optimum value as in the related art. There is no need to set, and it is possible to bring out the maximum performance of the main lens. In this state, in order to further reduce the electron beam spot diameter Ds, the lens strength of the three-pole lens formed in the three-pole part is increased, and the diameter of the electron beam in the crossover part is further reduced. or by reducing the electron beam passing holes of the electron beam passing holes and a second grid electrode 52 of the first grid electrode 51 constituting the triode, the cathodes 50 _1, 50 _2, 50 ₃ and the first grid electrode 5
For example, the distance from the electron beam 1 is reduced, and the aberration of the electron beam at the three poles is reduced.

[0020]

However, a color cathode ray tube equipped with the above-mentioned known DF type in-line electron gun is:
The electron beam passage hole of the first grid electrode 51 and the electron beam passage hole of the second grid electrode 52 in the three-pole portion of the DF in-line electron gun 47 are reduced, and the cathodes 50 ₁ , 5
0 _2, 50 ₃ and by or reduce the distance between the first grid electrode 51, but those that reduce the aberration of the electron beam in the triode reduces the aberration of the electron beam to beyond a certain Then, the cut-off voltage of the color cathode ray tube is reduced. At this time, the three-pole lens becomes weak, and the current density of the cathode current decreases.
There is a problem that the effect of reducing the aberration is reduced by half, and as a result, the focus characteristics cannot be improved.

The present invention solves such a problem. It is an object of the present invention to significantly reduce the aberration of the electron beam in the three-pole portion of the DF type in-line electron gun and improve the focus characteristics. The present invention provides a color cathode ray tube having the above characteristics.

[0022]

In order to achieve the above object, a color cathode ray tube according to the present invention is characterized in that an in-line electron gun comprises a triode comprising a cathode, a first grid electrode, and a second grid electrode; A first lens group, a second group of grid electrodes, and a focusing lens unit including an anode, wherein the first group of grid electrodes has a fixed first focusing voltage, and the second group of grid electrodes has a fixed voltage according to the amount of electron beam deflection. And a second focusing voltage on which a dynamic voltage that varies with the first grating electrode is applied. An electrostatic quadrupole lens is formed between the first group of grating electrodes and the second group of grating electrodes. The vertical diameter of the beam passage hole is G
1VR, horizontal diameter G1HR, area S1, second
The vertical diameter of the electron beam passage hole of the grid electrode is G2VR,
When the horizontal diameter is G2HR and the area is S2, G1
VR> G2VR, G1HR> G2HR, 0.096 ≦ S
Means are provided for satisfying 1 ≦ 0.115 and 0.070 ≦ S2 ≦ 0.115.

According to the above means, the DF type in-line electron gun has an electrostatic quadrupole lens formed on the focusing electrode, so that astigmatism of the electron beam spot caused by deflection can be corrected, and A more uniform spot diameter can be obtained over the entire area. Accordingly, in order to reduce the influence of astigmatism due to deflection, the electron beam diameter Do
Although ut is set smaller than the optimum value and the spot diameter is sacrificed, the electron beam diameter Dout can be set to the optimum value of the main lens.

Further, according to the above-mentioned means, between the vertical diameter G1VR, the horizontal diameter G1HR, and the area S1 of the electron beam passage hole in the first lattice electrode, and in the vertical direction of the electron beam passage hole in the second lattice electrode. G1VR> G2VR between the direction diameter G2VR, the horizontal direction diameter G2HR and the area S2,
G1HR> G2HR, 0.096 ≦ S1 ≦ 0.115,
Since the configuration is such that 0.070 ≦ S2 ≦ 0.115, it is possible to achieve both an increase in lens strength and a reduction in aberration in the three-pole portion, and it is possible to improve focus characteristics.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the present invention, a color cathode ray tube has a fluorescent surface attached to an inner surface of a face plate of a panel, a deflection yoke attached to an outer periphery of a funnel, and an in-line electron gun in a neck. The in-line electron gun has three in-line arrangements.
A three-electrode portion composed of two cathodes, a first lattice electrode and a second lattice electrode, and a focusing lens portion composed of at least a first group of lattice electrodes, a second group of lattice electrodes, and an anode. And a second focusing voltage obtained by superimposing a constant voltage on a dynamic voltage that varies according to the amount of deflection of the electron beam is applied to the second group of grid electrodes. An electrostatic quadrupole lens is formed between the second group and the second group. An electron beam passage hole of the first grid electrode has a vertical diameter G1VR, a horizontal diameter G1HR, an area S1, and a second grid electrode. G2VR, G2HR, G2VR, G1HR> G2HR, G1HR> G2HR when the diameter of the electron beam passage hole in the vertical direction is G2VR, the diameter in the horizontal direction is G2HR, and the area is S2.
0.096 ≦ S1 ≦ 0.115, 0.070 ≦ S2 ≦
It satisfies 0.115.

In one embodiment of the present invention, in the color cathode ray tube, the first group of grid electrodes and the second group of grid electrodes are composed of the first group of third grid electrodes and the second group of third grid electrodes. .

In one specific example of the embodiment of the present invention, the color cathode ray tube has a fourth grid electrode conductively coupled to the anode between the third grid electrode second group and the anode. Is what it is.

In another embodiment of the present invention, the color cathode ray tube comprises a first group of grid electrodes and a second group of grid electrodes comprising a first group of fifth grid electrodes and a second group of fifth grid electrodes. It is.

In one specific example of another embodiment of the present invention, the color cathode ray tube comprises a third grid electrode and a fourth grid electrode between a second grid electrode and a fifth grid electrode first group. An electrode is disposed, and a sixth lattice electrode electrically connected to the anode is disposed between the second group of fifth lattice electrodes and the anode.

In these embodiments of the present invention,
Since the DF in-line electron gun forms an electrostatic quadrupole lens on the focusing electrode, the electrostatic quadrupole lens corrects the astigmatism of the electron beam spot.

Generally, in order to reduce the electron beam spot diameter Ds in a color cathode ray tube having an in-line electron gun, it is necessary to reduce the dimensions of the first grid electrode and the second grid electrode of the in-line electron gun. In response to such a reduction in the size of the first grid electrode and the second grid electrode, the minimum value of the hole area of the electron beam passage holes of the first grid electrode and the second grid electrode is limited by the durability and manufacturing of the press machine. Depends on the accuracy, etc.
We have found that its minimum limit is 0.07 mm ² .

The present inventors examined the relationship between the area of the electron beam passage hole of the first grid electrode and the cut-off voltage of the color cathode ray tube, and found that the area of the electron beam passage hole was 0.0%.
It has been found that when the thickness is 96 mm ² or less, the cut-off voltage of the color cathode-ray tube decreases, and it becomes impossible to secure 110 V required for the cut-off voltage.

Further, the present inventors examined the relationship between the area of each electron beam passage hole of the first grid electrode and the second grid electrode and the electron beam spot diameter of a color cathode ray tube for displaying an ultra-high definition image. , The electron beam spot diameter capable of ensuring a resolution response of 0.2 mm is 0.6 mm, and the area of the electron beam passage hole of the first grating electrode for obtaining such an electron beam spot diameter is 0.115 mm or less. I found something.

Based on these findings, in these embodiments of the present invention, the first grid electrode and the second grid electrode of the DF type in-line electron gun are perpendicular to the electron beam passage holes of the first grid electrode. Direction diameter G1VR and horizontal diameter G
1HR and the area S1, and the vertical diameter G2VR and the horizontal diameter G2HR of the electron beam passage hole of the second grid electrode.
G1VR> G2VR, G1H between
R> G2HR, 0.096 ≦ S1 ≦ 0.115, 0.0
Since the configuration is such that 70 ≦ S2 ≦ 0.115 is satisfied, the aberration of the triode portion can be greatly reduced while maintaining the lens strength in the triode portion, and the focus characteristics of the color cathode ray tube can be improved. .

[0035]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a horizontal sectional view showing the structure of a first embodiment of a color cathode ray tube according to the present invention.

In FIG. 1, 1 is a panel portion, 1F is a panel face plate, 2 is a neck portion, 3 is a funnel portion, 4 is a fluorescent surface, 5 is a shadow mask, 6 is an internal conductive film, and 7 is dynamic focus. System (DF system) inline electron gun, 8 has a saddle / saddle type deflection angle of 10
This is a 0 ° deflection yoke.

In the DF in-line electron gun 7, reference numeral 10 ₁ denotes a left cathode, 10 ₂ denotes a center cathode, 10 ₃ denotes a right cathode, 11 denotes a first grid electrode, 12 denotes a second grid electrode, and 1 denotes a second grid electrode.
3 (1) is a first group of third grid electrodes, 13 (2) is a second group of third grid electrodes, 14 is a fourth grid electrode, 15 is a shield cup (anode), 16 is a vertical electrode piece, and 17 is a horizontal electrode. It is an electrode piece.

The glass bulb constituting the color cathode ray tube has a panel section 1 having a face plate 1F.
And a neck portion 2 having a small diameter, and a funnel portion 3 having a substantially funnel shape connecting the panel portion 1 and the neck portion 2. A fluorescent surface 4 is formed on the inner surface of the face plate 1F, and a shadow mask 5 is mounted inside the panel portion 1 so as to face the fluorescent surface 4. An internal conductive film 6 is formed on the inner surface of the funnel 3, and a deflection yoke 8 is mounted on the outer periphery of the funnel 3. The DF type in-line electron gun 7 is housed inside the neck portion 2.

The DF type in-line electron gun 7 has a left cathode 10 ₁ , a center cathode 10 ₂ , and a right cathode 10 ₃ arranged in-line in the horizontal direction, and the respective cathodes 10 ₁ , 10 ₂ , 10
In front of the ₃ along the axial direction of the tube, the first grid electrode 11, second
The grid electrode 12, the third grid electrode first group 13 (1), the third grid electrode second group 13 (2), the fourth grid electrode 14, and the shield cup 15 are arranged in this order. The fourth grid electrode 14 and the shield cup 15 are connected to each other in the tube axis direction. First grid electrode 11, second grid electrode 1
2, third grid electrode first group 13 (1), third grid electrode second
Group 13 (2), fourth grid electrode 14, shield cup 15
In each case, the center axis of each of the cathodes 10 ₁ , 10 ₂ , 10 ₃
To match the central axes O ₁ , O ₂ , O ₃ of
Three electron beam passage holes are provided on the left, center, and right sides.

[0041] In this case, in the fourth grid electrode 14, a central electron beam passage hole is provided in a position corresponding to the central axis O ₂ of central cathode 10 ₂ whose center line corresponds, the left electron beam passage holes , The left side cathode 1 of which the center line corresponds
0 provided at a position slightly displaced outwardly with respect to the _first center axis O _1, the right electron beam passing holes is slightly outwardly with respect to the central axis O ₃ of the right cathode ₁₀₃ to which the center line corresponds It is provided at a displaced position.

The first group 13 (1) of third grid electrodes includes vertical electrode pieces 16 which individually sandwich three electron beam passage holes from the vertical direction at positions opposed to the second group 13 (2) of third grid electrodes. The second group of third grid electrodes 13 (2) is provided with a horizontal electrode piece 17 sandwiching the three electron beam passage holes from the horizontal direction at a position facing the vertical electrode piece 16. Third grid electrode first group 13 (1) and third grid electrode second group 13 (2)
Vertical electrode piece 16 and horizontal electrode piece 17 provided between
Constitutes an electrostatic quadrupole lens.

A voltage of about 0 V or close thereto is applied to the first grid electrode 11, a relatively low voltage of about 400 to 1000V is applied to the second grid electrode 12, and the third grid electrode first group 13 (1) is applied. ), A constant focusing voltage Vs of about 5 to 10 kV is applied, and the third grid electrode second group 13 is applied.
A focusing voltage (Vs + Vd) in which a dynamic voltage Vd that varies according to the amount of electron beam deflection is superimposed on a constant focusing voltage Vs is applied to (2), and the fourth grating electrode 14, the shield cup 15, and the inner conductive film 6 are applied. Is applied with the anode voltage Vp.

FIGS. 2A and 2B are plan views showing examples of the structure of the electron beam passage holes provided in the first grid electrode 11 and the second grid electrode 12, respectively. Is a configuration example of the first grid electrode 11, and (b) is a second grid electrode 12.
1 shows an example of the configuration.

In FIGS. 2A and 2B, reference numeral 11H denotes three electron beam passage holes provided in the first grid electrode 11, and 12H.
H denotes three electron beam passage holes provided in the second grid electrode 12, and the same components as those shown in FIG. 1 are denoted by the same reference numerals.

As shown in FIGS. 2A and 2B, the three electron beam passage holes 11H of the first grating electrode 11 have the same shape and the same size, that is, have a vertical diameter of G1.
VR, the diameter in the horizontal direction is G1HR, the area is S1, and the three electron beam passage holes 12 of the second grid electrode 12 are formed.
H has the same shape and the same size, the vertical diameter is G2VR, the horizontal diameter is G2HR, and the area is S2.
It is.

In this case, each electron beam passage hole 11H, 1
2H is configured to satisfy G1VR> G2VR, G1HR> G2HR, and as described later,
0.096 ≦ S1 ≦ 0.115, 0.070 ≦ S2 ≦
It is configured to satisfy 0.115.

Next, FIG. 3 is a characteristic diagram showing the relationship between the cut-off voltage of the color cathode ray tube and the area S1 of the three electron beam passage holes 11H of the first grid electrode 11.

In FIG. 3, the vertical axis represents the cut-off voltage of the color cathode ray tube represented by V, and the horizontal axis represents the area S1 of the three electron beam passage holes 11H of the first grating electrode 11 represented by mm ^2. .

FIG. 4 shows a fluorescent screen 4 of a color cathode ray tube.
Of the electron beam spot projected on the substrate and the first grid electrode 11
FIG. 9 is a characteristic diagram showing a relationship between the area S1 of the three electron beam passage holes 11H and the area S2 of the three electron beam passage holes 12H of the second grid electrode 12.

In FIG. 4, the vertical axis represents the electron beam spot diameter in mm, and the horizontal axis represents the area S1 of the three electron beam passage holes 11H of the first grid electrode 11, the second grid electrode 1
2 is the area S2 of the three electron beam passage holes 12H.

Here, the operation of the color cathode ray tube of the first embodiment having the above configuration will be described as follows.

Each cathode 10 of the DF type in-line electron gun 7
_The three electron beams emitted from ₁ , 10 ₂ , and 10 ₃ are along their central axes O ₁ , O ₂ , and O ₃ , respectively, along the first grid electrode 11, the second grid electrode 12, and the third grid electrode. 1 group 13
(1) The third grid electrode second group 13 (2), the fourth grid electrode 14, and the electron beam passing holes provided in the shield cup 15, respectively, advance while being accelerated and focused. The light is emitted toward the light surface 4. The three electron beams emitted from the DF type in-line electron gun 7 are appropriately deflected in the horizontal and vertical directions by receiving a deflection magnetic field generated by the deflection yoke 8, and then are deflected in the corresponding electron beam passage holes of the shadow mask 5. Fluorescent screen 4 through
And a required image is displayed on the fluorescent screen 4.

In this case, the DF type in-line electron gun 7
Is the third grid electrode second group of the third grid electrode first group 13 (1).
The vertical electrode pieces 16 provided on the group 13 (2) side and the horizontal electrode pieces 17 provided on the third grid electrode first group 13 (1) side of the third grid electrode second group 13 (2) are static. An electric quadrupole lens is formed, and a focused voltage (Vs + Vd) including a dynamic voltage Vd that changes according to the amount of electron beam deflection is supplied to the third grid electrode second group 13 (2).

When the electron beam scans the central portion of the fluorescent screen 4 and the electron beam deflection amount is zero or extremely small, the dynamic voltage Vd is zero or extremely small. The focus voltage Vs supplied to the third grid electrode first group 13 (1) and the focus voltage (Vs + V) supplied to the third grid electrode second group 13 (2)
The same or almost the same as d), the lens strength of the electrostatic quadrupole lens is weakened, and the electron beam spot at the central portion of the fluorescent screen 4 does not cause astigmatism. On the other hand, when the peripheral portion of the fluorescent screen 4 is scanned by the electron beam and the electron beam deflection amount is large, the dynamic voltage has a large value.
3 (1), compared with the focusing voltage Vs supplied to the third grid electrode second group 13 (2).
Since d) increases, the lens strength of the electrostatic quadrupole lens increases, and the electron beam spot around the fluorescent screen 4 causes astigmatism. At this time, the astigmatism generated in the electron beam spot is generated by the deflection yoke 8 when the self-convergence deflection yoke is used because the core portion is elongated in the vertical direction and the halo is elongated in the horizontal direction. It is possible to cancel the deflection aberration and improve the resolution of the image displayed on the peripheral portion of the fluorescent screen 4.

As described above, the color cathode ray tube having the DF type in-line electron gun 7 of the first embodiment supplies the focused voltage (Vs + Vd) including the dynamic voltage Vd to the third grid electrode second group 13 (2). Thereby, the astigmatism of the electron beam spot can be corrected.

Further, in the color cathode ray tube of the first embodiment, as shown in FIG. 3, the cut-off voltage of the color cathode ray tube is reduced by the electron beam passage hole 11H of the first grid electrode 11.
The cutoff voltage decreases as the area S1 of the electron beam passage hole 11H decreases, and the cutoff voltage increases as the area S1 of the electron beam passage hole 11H increases.

In this case, the cut-off voltage required for the color cathode ray tube is at least 110 V. Based on the characteristics shown in FIG. 3, the electron beam of the first grid electrode 11 can secure the cut-off voltage of at least 110 V. The minimum value of the area S1 of the passage hole 11H is 0.096 mm ² .

Further, in the color cathode ray tube of the first embodiment, as shown in FIG. 4, the diameter of the electron beam spot projected on the fluorescent surface 4 of the color cathode ray tube is The electron beam spot diameter changes with the area S1 of the hole 11H and the area S2 of the electron beam passage hole 12H of the second grid electrode 12, and as the area S1 of the electron beam passage hole 11H and the area S2 of the electron beam passage hole 12H decrease. The electron beam passage hole 11
As the area S1 of H and the area S2 of the electron beam passage hole 12H increase, the electron beam spot diameter increases.

In this case, the smaller the electron beam spot diameter is, the higher the resolution of an image can be displayed. The maximum electron beam spot diameter capable of ensuring a resolution response of 0.2 is 0.6 mm. is there. Then, based on the characteristics shown in FIG. 4, the area S1 of the electron beam passage hole 11H of the first lattice electrode 11 and the electron beam passage hole 12H of the second lattice electrode 12 that can obtain an electron beam spot diameter of at most 0.6 mm are obtained. The maximum value of the area S2 is 0.115 mm ²
become.

In addition, in the color cathode ray tube of the first embodiment, the electron beam passage holes 11H of the first grid electrode 11 are provided.
The area S2 of the electron beam passage hole 12H is made smaller than the area S1 of the electron beam passage hole 11H in order to increase the lens strength of the prefocus lens formed between the electron beam passage hole 12H and the electron beam passage hole 12H of the second grid electrode 12. Specifically, the vertical diameter G1VR of the electron beam passage hole 11H,
Horizontal diameter G1HR and electron beam passage hole 12H
Between the diameter G2VR in the vertical direction and the diameter G2HR in the horizontal direction, G1VR> G2VR and G1HR> G2HR.

In consideration of these points, in the color cathode ray tube of the first embodiment, the area S1 of the electron beam passage hole 11H of the first grid electrode 11 is set to 0.096 ≦ S
The configuration is such that 1 ≦ 0.115 is satisfied, and the area S2 of the electron beam passage hole 12H of the second grid electrode 12 is configured to satisfy 0.070 ≦ S2 ≦ 0.115.

With such a configuration, the size of the electron beam diameter on the output surface of the main lens can be selected to be a size that minimizes the diameter of the electron beam spot projected on the fluorescent screen 4. (3) The aberration of the electron beam in the triode portion is greatly reduced, and the focus characteristics of the color cathode ray tube can be improved.

FIG. 5 is a sectional view showing the structure of a color cathode ray tube according to a second embodiment of the present invention.

In FIG. 5, reference numeral 18 denotes a third grid electrode;
(1) is a first group of fifth grid electrodes, 19 (2) is a second group of fifth grid electrodes, 20 is a sixth grid electrode, and other components that are the same as those shown in FIG. The same reference numerals are used.

The third grid electrode 18 is disposed immediately after the second grid electrode 12 (on the fluorescent screen 4 side).
Immediately after (the fluorescent screen 4 side), the fourth grid electrode 14 is arranged. The first group 19 (1) of the fifth grid electrodes is the fourth grid electrode 14
(The fluorescent screen 4 side), and the fifth grid electrode second group 19 (2) is provided immediately after the fifth grid electrode first group 19 (1) (the fluorescent screen 4 side). The sixth grid electrode 20 is disposed immediately after the fifth grid electrode second group 19 (2) (on the fluorescent screen 4 side), and a shield cup (anode) 15 is disposed in a state of being conductively connected to the sixth grid electrode 20. Is done.

The first group 19 (1) of fifth grid electrodes has vertical electrode pieces 16 which individually sandwich three electron beam passage holes from the vertical direction at positions facing the second group 19 (2) of fifth grid electrodes. The second group 19 (2) of fifth grid electrodes is provided with a horizontal electrode piece 17 sandwiching the three electron beam passage holes from the horizontal direction in common at a position facing the vertical electrode piece 16. Fifth grid electrode first group 19 (1) and fifth grid electrode second group 19 (2)
Vertical electrode piece 16 and horizontal electrode piece 17 provided between
Constitutes an electrostatic quadrupole lens.

A voltage of about 0 V or a voltage close thereto is applied to the first grid electrode 11, a relatively low voltage of about 400 to 1000V is applied to the second grid electrode 12 and the fourth grid electrode 14, and the third grid electrode 18 and the fifth grid electrode first group 19 (1) have a constant focusing voltage V of about 5 to 10 kV.
s is applied to the fifth grid electrode second group 19 (2), and a focusing voltage (Vs + V) obtained by superimposing a constant focusing voltage Vs and a dynamic voltage Vd that varies according to the amount of deflection of the electron beam.
d) is applied, the sixth grid electrode 20, the shield cup 1
Anode voltage Vp is applied to 5 and internal conductive film 6.

As shown in FIG. 2, the lens strength of the prefocus lens formed between the electron beam passage hole 11H of the first lattice electrode 11 and the electron beam passage hole 12H of the second lattice electrode 12 is reduced. In order to increase the area S2 of the electron beam passage hole 12H, the area S2 of the electron beam passage hole 11H is increased.
1, specifically, the electron beam passage hole 11
H, a vertical diameter G1VR, a horizontal diameter G1HR, and a vertical diameter G2VR of the electron beam passage hole 12H.
G1VR> G2VR, G between horizontal diameters G2HR
1HR> G2HR, and at the same time,
In order to reduce the size of the electron beam diameter on the output surface of the main lens to the size that minimizes the diameter of the electron beam spot projected on the fluorescent screen 4, the area S1 of the electron beam passage hole 11H of the first grating electrode 11 is set. , 0.096 ≦ S1 ≦ 0.1
15 and the second grid electrode 12
About the area S2 of the electron beam passage hole 12H of
The configuration is such that 70 ≦ S2 ≦ 0.115 is satisfied.

In the color cathode ray tube of the second embodiment having such a configuration, the size of the electron beam diameter on the output surface of the main lens is determined by the electron beam spot diameter, similarly to the color cathode ray tube of the first embodiment. The size can be selected to be minimized, and as a result, the aberration of the electron beam at the triode portion is greatly reduced, and the focus characteristic can be improved.

[0071]

As described above, according to the present invention, since the electrostatic quadrupole lens is formed on the focusing electrode in the DF type in-line electron gun, the electron beam spot is formed by the electrostatic quadrupole lens. Astigmatism can be corrected, and the vertical diameter G1VR and the horizontal diameter G1HR of the electron beam passage hole of the first grid electrode are provided with respect to the first grid electrode and the second grid electrode of the DF in-line electron gun. And the area S1 and the vertical diameter G2VR, the horizontal diameter G2HR, and the area S2 of the electron beam passage hole of the second grid electrode.
G1VR> G2VR, G1HR> G2H
R, 0.096 ≦ S1 ≦ 0.115, 0.070 ≦ S2
≦ 0.115, the size of the electron beam diameter on the output surface of the main lens can be selected to be the size corresponding to the minimum value of the electron beam spot diameter. This has the effect that the aberration of the electron beam in the section is greatly reduced, and the focus characteristics of the color cathode ray tube are improved, so that good resolution can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a first embodiment of a color cathode ray tube according to the present invention.

FIG. 2 is a plan view showing a configuration example of an electron beam passage hole provided in each of a first grid electrode and a second grid electrode.

FIG. 3 is a characteristic diagram showing a relationship between a cut-off voltage of a color cathode ray tube and areas of three electron beam passage holes of a first grid electrode.

FIG. 4 shows a relationship between the diameter of an electron beam spot projected on a fluorescent screen of a color cathode ray tube, the area of three electron beam passage holes of a first lattice electrode, and the area of three electron beam passage holes of a second lattice electrode. FIG.

FIG. 5 is a sectional view showing a configuration of a second embodiment of the color cathode ray tube according to the present invention.

FIG. 6 is a cross-sectional view showing a configuration of a color cathode ray tube including a known DF type in-line electron gun.

FIG. 7 is an explanatory diagram showing a focused state of three electron beams in the DF in-line electron gun shown in FIG.

FIG. 8 is a characteristic diagram showing focus characteristics of an inline electron gun in a color cathode ray tube having the inline electron gun.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Panel part 1F Panel part face plate 2 Neck part 3 Funnel part 4 Fluorescent surface 5 Shadow mask 6 Internal conductive film 7 Dynamic focus type (DF type) in-line electron gun 8 Deflection yoke 10 ₁ Left cathode 10 ₂ Central cathode 10 ₃ Right cathode 11 First grid electrode 12 Second grid electrode 13 (1) Third grid electrode first group 13 (2) Third grid electrode second group 14 Fourth grid electrode 15 Shield cup (anode) 16 Vertical electrode piece 17 Horizontal electrode piece 18 Third grid electrode 19 (1) Fifth grid electrode first group 19 (2) Fifth grid electrode second group 20 Sixth grid electrode

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shinichi Kato 3300 Hayano, Mobara City, Chiba Prefecture Inside the Electronic Device Business Division, Hitachi, Ltd. (72) Inventor Shoji Shirai 3300 Hayano, Mobara City, Chiba Prefecture Electronic Device Business, Hitachi, Ltd. (72) Inventor Tsuyoshi Uchida 3300 Hayano, Mobara City, Chiba Pref.Hitachi, Ltd.Electronic Device Division

Claims (5)

[Claims] 1. A color cathode ray tube wherein a fluorescent surface is attached to an inner surface of a face plate of a panel portion, a deflection yoke is attached to an outer periphery of a funnel portion, and an in-line electron gun is accommodated in a neck portion. A grid comprising three cathodes, a first grid electrode, and a second grid electrode, and a focusing lens unit including at least a first group of grid electrodes, a second group of grid electrodes, and an anode; A constant first focusing voltage is applied to the first electrode group, and a second focusing voltage obtained by superimposing a dynamic voltage that varies according to the amount of electron beam deflection on the constant voltage is applied to the second group of grid electrodes. An electrostatic quadrupole lens is formed between the first group of grid electrodes and the second group of grid electrodes, and the vertical diameter of the electron beam passage hole of the first grid electrode is G1VR,
The horizontal diameter is G1HR, the area is S1, and the vertical diameter of the electron beam passage hole of the second lattice electrode is G2VR.
When the diameter in the horizontal direction is G2HR and the area is S2, G1VR> G2VR, G1HR> G2HR, 0.096
≦ S1 ≦ 0.115, 0.070 ≦ S2 ≦ 0.115. 2. The color cathode ray according to claim 1, wherein the first group of grid electrodes and the second group of grid electrodes are a first group of third grid electrodes and a second group of third grid electrodes. tube. 3. The color cathode ray according to claim 2, wherein a fourth grid electrode conductively coupled to the anode is arranged between the second group of the third grid electrodes and the anode. tube. 4. The color cathode ray according to claim 1, wherein the first group of grid electrodes and the second group of grid electrodes are a first group of fifth grid electrodes and a second group of fifth grid electrodes. tube. 5. A third grid electrode and a fourth grid electrode are arranged between the second grid electrode and the fifth grid electrode first group, and the fifth grid electrode second group, the anode, 5. The color cathode ray tube according to claim 4, wherein a sixth grid grid electrode conductively coupled to the anode is disposed between the cathode grid electrodes.