JP3264254B2 - CRT - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly to a cathode ray tube in which an electron gun having a cathode electron source is disposed inside a vacuum vessel.

[0002]

2. Description of the Related Art A conventional cathode ray tube has a neck portion on which an electron gun is arranged, a funnel portion for scanning electrons in a two-dimensional direction, and a panel on which a phosphor for visualizing the electrons is applied and a shadow mask is arranged. And the highest potential Eb inside the shadow mask and the funnel.
Is given. This potential Eb is a high voltage of about 20 kV to 30 kV, and is the highest voltage among the potentials applied to the electron gun.

Here, the application of a voltage to the electron gun will be described with reference to FIG. The potential Eb is applied to G through a metal foot 101 that contacts the funnel interior graphite 100.
It is supplied to four electrodes 102. G3D electrode 103 and G3
The potential application to the S electrode 104 is performed by the G3D potential application wiring 10.
G3D potential applying pin 103b and G3S potential applying pin 1 connected to G3S potential wiring 104a and G3S potential wiring 104a, respectively.
04b.

[0004] In a region between the G4 electrode 102 and the G3D electrode 103, the main lens function of the electron gun is exhibited. As a standard potential, the potential of the G3D electrode 103 is about 25% of the potential Eb applied to the G4 electrode 102. Therefore, when the potential Eb is 24 kV, the G3D electrode 1
03 has a potential of about 6 kV. When this potential relationship is maintained, the beam diameter is reduced to the minimum at the center of the panel surface. Since the electron beam emitted from the electron gun is scanned two-dimensionally in the funnel portion, the traveling length of the beam becomes long at the end portions swung up, down, left, and right, and if it remains at 6 kV, it will be blurred due to overfocus. .

Therefore, in order to adjust the focus at this end, it is necessary to set a potential higher than 6 kV.
The optimum focus potential for 17-inch scanning is set to be about 10% at the corner portion, that is, 600 V higher than at the center portion. Accordingly, an intermediate potential between these potentials is given in an intermediate region between the corner portion where the potential is set to 6.6 kV and the center portion where the potential is set to 6 kV.
The potential of the G3D electrode 103 changes in a range from 6.6 kV to 6 kV during the scanning period.

On the other hand, the G3S potential is fixed at 6 kV, and the cathode electron source 105, the G1 electrode in the immediate vicinity thereof, and the G2 electrode between the G1 electrode and the G3 electrode function comprehensively to adjust the beam as a blur focus lens. Let it. The CRT shown in the figure shows an example of an in-line color system in which three hot cathodes are arranged on a straight line, and the electron gun in the figure is covered with a neck glass 106. As this type of cathode ray tube, a cathode ray tube disclosed in Japanese Patent Application Laid-Open No. 7-153388 is known.

[0007]

The above-mentioned conventional cathode ray tube has the following problems. First, 6k
The fact that it is difficult to generate a high voltage of V or more with good controllability will be described. G3D electrode 103 and G3S electrode 10
4 is the potential Eb generated by the flyback transformer.
Generate using. The potential Eb and the ground potential are connected by a high-resistance thick-film resistance pattern, and a tap electrode is provided in the middle of the resistance to obtain a desired potential.

In general, in order to adjust the potential to the desired value, a component called a focus unit having a mechanical mechanism for bringing a tap into contact with an arbitrary position of a thick film resistor is used. Since this potential adjustment must be performed by rotating the shaft provided in the high-resistance portion, it is dangerous for a purchaser with little electrical knowledge to make an adjustment himself after the purchase. In some cases, the film resistance was rubbed off. Therefore, since the purchaser was not able to expect such fine adjustment, the cathode ray tube had to be adjusted arbitrarily in the manufacturing process, so even though the ideal applied voltage was originally determined as its own characteristic, Regardless, this ideal potential was not sufficiently applied to the G3D electrode 103 and the G3S electrode 104. For this reason, the original characteristics cannot be exhibited, and power consumption due to the leakage current flowing through the thick film resistor and deterioration and damage due to long-term energization have been problems.

The G3D electrode 103 and the G3S electrode 1
04 is supplied to a potential applying pin by tailoring a high-voltage cable, so that a G3D
In addition to the electrode 103 and the G3S electrode 104, each pin of the G2 electrode (about 500 V), the G1 electrode (about 0 V), the cathode (RGB several tens V), and the heater (about 0 V) was tight.
However, considering the withstand voltage, it is impossible to arrange another potential applying pin in the vicinity of a pin to which a potential of 6 kV is applied, so that a large space is required in a valuable stem portion where many pins are to be provided. As described above, in order to generate a high-voltage potential of 6 kV or more and supply it to the G3D electrode 103 or the G3S electrode 104, much labor and cost had to be spent.

[0010] The present invention has been made in view of the above problems, and has as its object to provide a cathode ray tube capable of reducing labor and cost.

[0011]

To achieve the above object, according to an aspect of, the invention according to claim 1, the electron gun comprising a cathode electron source in a cathode ray tube placed inside the vacuum vessel, the inside of the shadow mask and the funnel portion Give electricity
Connected to the middle of a resistor that divides resistance between ground and ground potential.
Supply means for irradiating free electrons to the adjustment terminal
Is provided in a cathode ray tube separately from the cathode electron source .

That is, electron supply means having an electron source separately from the cathode electron source emits electrons and supplies them to the adjustment terminal of the lens electrode of the electron gun. At this time, the cathode potential for supplying the electrons by the amount of electrons jumping into the adjustment terminal of the lens electrode and the potential of the lens electrode
Conductance is generated between the adjustment terminal and the adjustment terminal . Therefore, the lens electrode potential approaches the cathode potential by this conductance, and the lens electrode can be adjusted by adjusting the electron quantity.

By the way, in order to adjust the cathode potential, it is sufficient to control the heater power or the potential of the electrode associated with the electron extraction. Since the potential required for these adjustments can be set to a low potential, as a result, the potential of the lens electrode can be controlled by adjustment in a potential region irrelevant to the actual potential of the lens electrode. Since the jumping electrons travel in a vacuum, there is little fear that a high voltage suddenly flows into the circuit for controlling the amount of the jumping electrons due to some leak current.

As an example of the configuration of the electron source for the adjustment terminal , the invention according to claim 2 is the cathode ray tube according to claim 1, wherein the electron supply means includes a microfield emitter. That is, the microfield emitter emits electrons and supplies them to the adjustment terminal of the lens electrode of the electron gun.

According to a third aspect of the present invention, as an example of a configuration for adjusting the amount of electrons supplied to the adjustment terminal of the lens electrode, a cathode ray tube according to the first or second aspect is provided. The electron supply means includes a lens electrode of the electron gun or a lens electrode of the lens electrode.
The amount of electrons supplied to the lens electrode or the adjustment terminal is controlled by changing the trajectory of the electrons supplied to the adjustment terminal . That is, the electron supply means adjusts the lens electrode of the electron gun or the lens electrode.
The trajectory of electrons supplied to the adjustment terminal is changed, and the amount of electrons supplied to the lens electrode or the adjustment terminal is controlled.

As described above, as an example of a configuration for changing the trajectory of the electrons supplied to the adjustment terminal of the lens electrode,
According to a fourth aspect of the present invention, in the cathode ray tube according to the third aspect, the electron supply means includes an adjustment deflection electrode capable of changing the trajectory of the electrons inside the vacuum vessel. That is, the adjustment deflection electrode arranged inside the vacuum vessel changes the trajectory of the electrons.

As another example, the invention according to claim 5 is the cathode ray tube according to claim 3, wherein the electron supply means changes the trajectory of the electrons to the outside of the vacuum vessel. The configuration is provided with a coil that can be used. That is, the coil arranged outside the vacuum vessel changes the trajectory of the electrons.

The electron supply means may be one having an electron source separate from the cathode electron source, and may be one having another electron source in advance, or the same electron source may be separated. It may be used.

As an example of the configuration of the electron supply means in the latter case, the invention according to claim 6 is the same as that of claim 1
6. The cathode ray tube according to claim 5, wherein the electron supply means applies a plurality of lens electrodes that need to apply different potentials to the electron gun by controlling the amount and trajectory of electrons from a single electron source. It is configured to control the potential. That is, by controlling the amount and trajectory of the electrons from the single electron source and the electron source separated from the cathode electron source, the potential applied to a plurality of lens electrodes of the electron gun that require different potentials is controlled.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration of a neck portion of a color cathode ray tube according to the present embodiment.

In the neck portion 10 of the color CRT,
A G4 electrode 13 connected via a metal foot 12 in contact with the funnel-containing graphite 11, an electron gun G3D14 adjacent to the G4 electrode 13, and an electron gun G3S electrode 15 adjacent to the electron gun G3D14 are arranged. G4
The main lens function of the electron gun is exhibited in a region between the electrode 13 and the G3D electrode 14. As a standard potential, the potential of the G3D electrode 14 is the potential E applied to the G4 electrode 13.
b is applied, the potential Eb becomes 24 kV
In this case, the potential of the G3D electrode 14 is about 6 kV.

When this potential relation is maintained, the beam is narrowed down to the minimum beam diameter at the center of the panel surface. Since the electron beam emitted from the electron gun is scanned two-dimensionally in the funnel portion, the traveling length of the beam becomes longer at the end portions swung up, down, left, and right.
For example, the optimal focus potential for 17-inch scanning is:
Approximately 10% at the corner compared to the center, ie 600
V is set higher. Therefore, an intermediate region between the corner portion of the 6.6 kV potential and the center of the 6 kV potential is provided with an intermediate potential of these potentials.
It changes in the range of 6.6 kV to 6 kV during the scanning period.

On the other hand, the potential of the G3S electrode 15 is fixed at 6 kV, and the cathode electron source 16 and the G2 electrode between the G1 electrode and the G3S electrode 15 in the immediate vicinity function as a prefocus lens. Prepare the beam. In addition,
This electron gun is covered with a neck glass 17.

The G3D electrode 14 has a G3D adjustment terminal 14
a G3D adjustment terminal 14a
Is made of stainless steel with a thickness of 0.5 mm and a length of 2 mm.
The width of the contact surface with the D electrode 14 is a rectangular parallelepiped of 5 mm. The other end of the G3D adjustment terminal 14a is in contact with the G3D resistor 14b. The G3D resistor 14b has a resistance value between both ends of 24 GΩ, and this end is connected to a metal foot 1.
2 and a G3D resistor ground pin 14 at the other end.
c is electrically connected.

The connection position of the G3D adjustment terminal 14a is a position where the resistance of the G3D resistor 14b is divided into 70%: 30%, and the resistance from the G3D resistor ground pin 14c is the resistance of the entire resistor. It is connected so as to be 30%. Therefore, when 24 kV is applied to the potential Eb, 7.2 kV corresponding to 30% of this is applied.

Here, a procedure for finely adjusting the potential of the G3D electrode 14 will be described. Free electrons emitted from the G3D cathode 14d formed of a heater at the ground potential jump into the G3D adjustment terminal 14a. Although the G3D cathode 14d has only one terminal in the drawing, it is actually provided with two terminals for energizing and heating itself. The amount of free electrons jumping out of the G3D cathode 14d is 1 m from the G3D cathode 14d.
It is adjusted by the space charge control electrode 14e having a pinhole with a hole diameter of 0.4 mm arranged at the position of m. If the potential of the space charge control electrode 14e is set to the ground potential, that is, 0V, free electrons are not extracted.

On the other hand, when the potential of the space charge control electrode 14e is set to a positive potential, free electrons are extracted. By appropriately adjusting the filament temperature, the space charge control electrode 1
0 e when the potential of 4e is 0 V, 0.1 when the potential is 20 V
Emit 0.3 μA free electrons at μA and 30V. The control electrode 14f converges the free electrons that have passed through the space charge control electrode 14e and irradiates the G3D adjustment terminal 14a with a narrow beam. At this time, the length is 2 mm,
A voltage of 200 V or more is applied to the control electrode 14f in order to irradiate the entire free electron beam to the electrode having a width of 5 mm.
A desired free electron is generated by the G3D cathode 14d, the space charge control electrode 14e, and the control electrode 14f.
Irradiate the adjustment terminal 14a. In addition, voltage application to these is performed via the G3D adjustment pin 14g. The control electrode 14f may be shared with the G2 electrode in order to reduce the number of the G3D adjustment pins 14g.

The G2 electrode is one of the electrodes constituting the electron gun, and is arranged together with the G1 electrode near the cathode electron source 16 to control space charge and function as a prefocus lens. In some cases, the application of voltage and current to the G3D cathode 14d is common to the cathode heater of the RGB electron gun of the cathode ray tube. In some cases, the convergence characteristics of the control electrode are made slow to form a thick electron beam, thereby performing control to reduce electrons jumping into the G3D adjustment terminal 14a.

Here, the G3D electrode 14 having the configuration described above is used.
The procedure for adjusting the electric potential of is described. G3D resistor 1
4b is 24 Gigaohms and G3D adjustment terminal 14a
Is mounted at a position where the resistance from the ground side is 7.2 gigaohms. If the current amount of free electrons is described as IμA, the G3D potential VG3D (k
V) = 7.2-5.04XI (where I is μA). In the state where free electrons do not flow, the potential of the G3D electrode 14 is about 7.2 kV, and when I = 0.1 μA, about 6.
7 kV, about 5.7 kV. In connection with the free electron emission characteristics described above, the space charge control electrode 14e is set to 0V
When it is set to 7.2 kV, when set to 20 V, 6.7 kV,
When the voltage is set to 30 V, the potential of the G3D electrode 14 can be adjusted to 5.7 kV.

FIG. 2 shows this relationship by an equivalent circuit. The potential of the G3D electrode 14 is given a basic potential by resistance division (24 GΩ) between the potential Eb and the ground potential, and a constant current source having a current I is supplied to the G3D electrode as shown in FIG.
By arranging it at the same position as the electrode 14, the potential of the G3D electrode 14 can be adjusted.

Here, a procedure for adjusting the potential by the G3S potential adjusting mechanism in addition to the potential adjusting by the G3D potential adjusting mechanism described above will be described. The G3S electrode 15 has G3S
An adjustment terminal 15a is attached. The G3S adjustment terminal 15a has the same shape as the G3D adjustment terminal 14a and is made of tungsten. The position of the resistance from the G3S resistor ground pin 15c of the G3S resistor 15b is 70% of the total resistance, that is, 7.2 GΩ.

The microfield emitter 15d is arranged at a position where the G3D adjustment terminal 14a can be seen. The microfield emitter 15d is composed of a gate electrode 15e having a minute hole of 1 micron or less and an emitter cone 15f arranged in the minute hole, and both are insulated by a thin solid insulating film. Voltage is applied to the microfield emitter 15d by the G3S adjustment pin 1
Via 5 g. Free electrons are emitted by setting the G3D cathode 14d to 0 V and the gate electrode 15e to a positive potential.

At this time, by setting the potential around the gate electrode 15e to a potential more negative than that of the gate electrode 15e itself, the emitted electrons can be converged and irradiated to the G3S adjustment terminal 15a as a narrow beam. An example of the relationship between the potential difference and the amount of free electron current is 0 μm from 0 V to 20 V.
A, 0.1 μA at 30 V and 1 μA at 40 V. Note that this relationship is based on the size of the small hole diameter in the gate electrode 15e, the electric field strength due to the shape of the emitter cone 15f,
It changes depending on the number of emitter cones 15f.

In the microfield emitter 15d, the start of free electrons may be bent under the influence of the potential of the cathode electron source 16 and the G1 and G2 electrodes in the vicinity thereof. To prevent the amount of free electrons jumping into the G3S adjustment terminal 15a from changing due to this bending, when the microfield emitter 15d is brought closer to the G3S electrode 15, the distance between the microfield emitter 15d and the G3S adjustment terminal 15a is 1 mm. is there. The procedure for adjusting the potential of the G3S electrode 15 using the microfield emitter 15d is the same as that described above.

FIG. 3 is a sectional view showing the neck portion 20 of the cathode ray tube when the amount of electrons is controlled by changing the trajectory of free electrons. The funnel interior graphite 21 is a conductive layer having the same potential as Eb which is a tube surface voltage of a CRT, and has a potential of 24 kV. G3D electrode 2
The material and shape of the G3D adjustment terminal 22a in contact with 2 are the same as those described above. The potential at the G3D electrode 22 is set to 6.6 kV by adjusting the contact position with the G3D resistor 22b.

A microfield emitter 22c is provided near the stem, which is the bottom of the neck, and a voltage is applied to the gate electrode 22d and the emitter cone 22e by an electric field given by the G3D adjustment deflection electrode 22f. Traveling in vacuum. In the figure, a potential of 100 V is applied to the G3D adjustment deflection electrode 22f, the free electrons are bent to the left, and the feet are irradiated with the free electrons.

When a potential of 0 V is applied to the G3D adjustment deflection electrode 22f, free electrons enter the G3D adjustment terminal 22a,
The potential of the G3D adjustment deflection electrode 22f is 10 V, 2
In the case of 0V and 30V, the microfield emitter and the G3D adjustment deflection are set such that 90%, 80% and 70% of the free electrons enter the G3D adjustment terminal 22a and the rest enter the foot. Electrodes are arranged. When free electrons are directly incident on the foot, G3D
The potential of the electrode 22 remains at 6.6 kV.

When all the free electrons enter the G3D adjustment terminal 22a, the potential of the G3D electrode 22 becomes 6
The current amount of the free electrons is adjusted by adjusting the potential of the gate electrode 22d to be kV. In this state, the potential of the G3D adjustment deflection electrode 22f is driven in the range of 0 V to 100 V, the potential of the gate electrode 22d is driven between the gate electrode adjustment potential and the free electron emission threshold potential, or a combination of both. Thus, a dynamic focus operation can be performed. The G3D electrode 22 is made of a high-resistance material such as iron silicide or the thickness is reduced to increase the resistance.
Since there is an embodiment in which the 3D adjustment deflection electrode 22f is symmetrically disposed on the axis in the vertical direction also on the right side of the G3D electrode 22, the description will be made based on FIG.

In this structure, the electron incidence on the left and right G3D adjustment terminals 22a is alternately performed, that is, the left G3D adjustment terminal 22a is turned on.
When a large number of free electrons are incident on the adjustment terminal 22a, a small number of free electrons are incident on the right G3D adjustment terminal 22a. By this operation, the R held by the color electron gun is
The shift of the focus point due to the difference in the length of the trajectory of the free electrons from each of the GB cathodes can be corrected.

FIG. 4 is a sectional view showing a neck portion 30 of a cathode ray tube in a case where the trajectory of free electrons is changed by a magnetic field generated by a coil to control the amount of electrons. In this case, the above-described components are similarly arranged in a vacuum environment surrounded by the neck glass 31 except for the G3D adjustment deflection electrode 22f. The free electron current is G3
It is controlled by a voltage signal applied via the S adjustment pin 32a. The emitted free electrons bend their trajectories as shown in the figure by the magnetic field generated by the deflecting magnetic field generator 33 formed by the coil. The bent free electrons are
Jump into the G3S resistor 32b.

The diving position and the amount of free electron current are represented by G
The G3S resistor 32b is controlled by the voltage signal applied through the 3S adjustment pin 32a and the amount of current flowing through the coil.
Can be changed. In a range below the position where the G3S adjustment terminal 32c is attached to the G3S resistor 32b, the potential of the G3S electrode 32 decreases as the free electrons having a certain amount of current enter the upper part of the G3S resistor 32b. If the amount of current is increased while the light is incident on the same position in the above range, the potential of the G3S electrode 32 decreases. G
Even in a range above the position where the 3S adjustment terminal 32c is attached to the G3S resistor 32b, the G
The potential of the 3S electrode 32 decreases.

FIG. 5 is a sectional view showing the structure of the neck portion 40 of a cathode ray tube provided with a single electron source. The following members are stored in a vacuum environment surrounded by the neck glass 41. The potential of the G4 electrode 42, which is a high-voltage electrode in the main lens of the electron gun, is obtained from a not-shown interior graphite for tube potential via a metal foot 43. A resistive collector 44 is arranged adjacent to the electron gun at a position from the stem. At a position further from the stem of the resistive collector 44, a microfield emitter is arranged to emit free electrons.

In the vicinity of the microfield emitter, a distribution deflection pin 45 is arranged. The resistive collector 44 has a G3A high voltage pin 4 at each end.
4a and the G3B high voltage pin 44b. The resistive collector resistance between the two high voltage pins 44a and 44b is 1 MΩ. The resistive collector 44 has an intermediate tap 4
4c and 44d are provided at two places.

From the G3A high voltage pin 44a to the intermediate tap 44
The metal wiring from c is connected to the G3S electrode 46, and the metal wiring from the middle tap 44d through the G3B high voltage pin 44b is connected to the electron gun G3D electrode 47. The main factor that changes the focal length of the main lens of the electron gun is G4
This is a potential difference between the electrode 42 and the electron gun G3D electrode 47.

In a 17-inch 90-degree deflection CDT,
When the potential of the G4 electrode 42 is fixed at 24 kV, the potential of the G3D electrode 47 is designed to form a minimum diameter beam at the center of the surface of the cathode ray tube with a potential of about ４ of the potential. When the electron beam is deflected to the peripheral portion of the tube surface, for example, to a corner portion, the minimum diameter beam can be obtained by applying the potential of the G3D electrode 47 to about 600 V higher than the above ４ condition.

An astigmatism lens is formed between the G3D electrode 47 and the G3S electrode 46.
When the potential difference between the 3S electrode 46 and the 3S electrode 46 becomes large, the electron beam is adjusted to be a vertically long electron beam. As described above, the portrait orientation is used to correct the electron beam from being deflected horizontally for the in-line self-convergence operation.

First, the electron beam in the corner portion is adjusted by operating the cathode ray tube so that the electron beam is close to a perfect circle and the beam diameter is small. The specifications of the beam shape and beam diameter are determined in advance and adjusted so as to satisfy the specifications. A voltage is applied to the microfield emitter via the free electron emission adjusting pin 48 to emit free electrons. By applying a positive voltage to the distribution deflection pin 45, free electrons are deflected in a direction closer to the intermediate tap 44d from the G3B high voltage pin 44b of the resistive collector 44. Fine-tune each voltage to satisfy the above specifications.

Next, when the electron beam shape and the beam diameter at the center of the tube surface are adjusted to satisfy the predetermined specifications, free electrons are not emitted. Next, the same adjustment is performed at several positions between the center of the tube surface and the corner. At the time of this adjustment, free electrons are emitted by a predetermined amount determined in advance, and the deflection voltage is adjusted so as to satisfy the specifications. Alternatively, the amount of free electrons may be adjusted, or the voltage application to the two high voltage pins 44a and 44b may be adjusted. By repeating the above adjustment cycle several times, the adjustment is performed so that the beam diameter becomes close to a perfect circle and has a small beam diameter at all places on the tube surface.

Since the G3S electrode 46 also forms a lens between the adjacent G2 electrode, the lens specification with the G2 electrode is optimized at each tube position along with the potential adjustment by the tube surface position. The intermediate tap 44c from the G3A high-voltage pin 44a, the intermediate tap 44d from the G3B high-voltage pin 44b, and the free electron deflection characteristics are designed to be as follows.

FIG. 6 shows the G3D electrodes 47 and G3S shown in FIG.
The application of a potential to each of the electrodes 46 is shown by an equivalent circuit.
The G3A high voltage pin 44a and the G3B high voltage pin 44b and the free electrons apply the potential of the two electrodes 46 and 47. As described above, the cathode electron source 16 is provided inside the neck glass 17.
Since the G3D cathode 14d, which is arranged separately from the above, is controlled at a low voltage and the focus characteristic is adjusted, labor and cost can be reduced.

[0051]

As described above, according to the present invention, the focus characteristics such as the adjustment of the electron beam spot shape on the surface of the cathode ray tube and the adjustment of the beam diameter are easily performed by controlling the free electrons from the electron source for adjustment. be able to. The control of the free electrons can be performed at a low voltage, and since the vacuum is insulated from the high voltage part of the electron gun in the cathode ray tube, the control of the free electrons can be performed reliably without using an expensive protection circuit. A circuit can be configured. As a result, the manufacturing cost of the monitor device using this cathode ray tube is reduced.

Since the focus characteristic of the cathode ray tube can be controlled by the control circuit of the free electrons, the monitor device is completed.
After the sale, the user can adjust the focus characteristics over time according to his / her preference. With this, in addition to satisfaction of the user, since the adjustment of the cathode ray tube and the adjustment of the monitor device can be performed on the premise of the user adjustment, the respective costs, particularly the adjustment cost, can be reduced. Therefore, it is possible to provide a cathode ray tube capable of reducing labor and cost.

According to the second aspect of the present invention, the electron emission source is configured to jump into a region where various potential distributions are concerned by utilizing the characteristic that the amount of electrons generated by the microfield emitter is hardly affected by an external electric field. Can be provided. Further, according to the third aspect of the invention, the electric potential of the lens electrode can be controlled by changing the resistance distribution depending on the position where the electrons enter. Claim 4
According to the present invention, since the trajectory of the electrons can be changed by the adjustment deflection electrode disposed inside the vacuum vessel, the space can be saved.

Further, according to the invention of claim 5,
Since the trajectory of the electrons can be changed by a coil disposed outside the vacuum vessel, it can be realized with a simple configuration. Furthermore, according to the invention according to claim 6, the resistance piece is connected in a state where the plurality of lens electrodes are connected to an intermediate tap of a resistance piece having an intermediate tap and a predetermined potential is applied to both ends of the resistance piece. The potential of the plurality of lens electrodes can be controlled by letting the controlled electrons dive.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a neck portion of a CRT according to an embodiment.

FIG. 2 is an equivalent circuit showing the relationship between the potential of a G3D electrode and free electron emission characteristics.

FIG. 3 is a cross-sectional view showing a configuration of a neck portion of a CRT in a case where the amount of electrons is controlled by changing the trajectory of free electrons.

FIG. 4 is a cross-sectional view showing a configuration of a neck portion of a cathode ray tube in a case where the amount of electrons is controlled by changing the trajectory of free electrons by a magnetic field generated by a coil.

FIG. 5 is a cross-sectional view illustrating a configuration of a neck portion of a CRT provided with a single electron source.

FIG. 6 is an equivalent circuit showing potential application to each of a G3D electrode and a G3S electrode.

FIG. 7 is a cross-sectional view showing a configuration of a neck portion of a cathode ray tube in a conventional example.

[Explanation of symbols]

 Reference Signs List 10 neck part 11 funnel interior graphite 12 metal feet 13 electron gun G4 electrode 14 electron gun G3D electrode 14a G3D adjustment terminal 14b G3D resistor 14c G3D resistor ground pin 14d G3D cathode 14e space charge control electrode 14f control electrode 14g G3D adjustment Pin 15 Electron gun G3S electrode 16 Cathode electron source

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 29/46 H01J 29/50 H01J 29/56

Claims (6)

(57) [Claims] 1. A cathode ray tube having an electron gun having a cathode electron source disposed inside a vacuum vessel , wherein a potential applied to the inside of a shadow mask and a funnel is determined.
A resistor connected in the middle of a resistor that performs resistance division with the ground potential
The electron supply means for irradiating free electrons to the
A cathode ray tube provided inside a cathode ray tube separately from the cathode electron source . 2. The cathode ray tube according to claim 1, wherein said electron supply means includes a microfield emitter. 3. The cathode ray tube according to claim 1, wherein the electron supply means changes a trajectory of electrons supplied to a lens electrode of the electron gun or an adjustment terminal of the lens electrode. A cathode ray tube, wherein an amount of electrons supplied to the lens electrode or the adjustment terminal is controlled. 4. The cathode ray tube according to claim 3, wherein the electron supply means includes an adjustment deflection electrode capable of changing the trajectory of the electrons inside the vacuum vessel. 5. The cathode ray tube according to claim 3, wherein said electron supply means includes a coil capable of changing the trajectory of said electrons outside said vacuum vessel. 6. The cathode ray tube according to claim 1, wherein said electron supply means applies different potentials to said electron gun by controlling the amount and trajectory of electrons from a single electron source. A cathode ray tube characterized by controlling potentials applied to a plurality of necessary lens electrodes.