JPS6224896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image display device, and more particularly to a thin image display device having a switching circuit using an electron gun.

A conventional device of this type is shown in FIG.

In the figure, 1a to 1f are striped anode strip wires (hereinafter referred to as anode strip wires), in which a metal thin film is provided on a fluorescent film, and 2a to 2e are striped cathode strip wires (hereinafter referred to as cathode strip wires). ), 3a to 3d are anode targets connected to each of the anode strip wires 1a to 1f, 4a to 4e are cathode targets connected to each of the cathode strip wires 2a to 2e, and 5 is orthogonal to the anode strip wires 1a to 1f. Needle cathodes for field emission (hereinafter referred to as needle cathodes) are provided at each point on the cathode band wires 2a to 2e as shown in FIG. A gun 7 is a cathode electron gun for bombarding the cathode target 4 with electrons, and these guns are enclosed in a vacuum container 8 whose front part is made of a transparent material such as glass.

FIG. 2 is a linear development of the relationship between the above-mentioned elements, and the same reference numerals as in FIG. 1 indicate the same elements.

Next, the operation will be explained.

The electron beam emitted from the anode electron gun 6 is scanned by a suitable deflection device (not shown) so as to sequentially impact the anode targets 3a to 3d.
The electron beam from the cathode electron gun 7 is scanned so as to sequentially impact the cathode targets 4a to 4e. At this time, at the point where the anode target 3e receiving the impact of the electron beam and the anode strip wire 1e connected thereto, and the cathode target 4d also receiving the impact of the electron beam and the cathode strip wire 2d connecting it intersect at right angles, The configuration is as shown in FIG.

In this case, the secondary electron emission coefficient σ of the anode target 3e is set to be larger than 1 by appropriately selecting its material and the energy of impact electrons, and the secondary electron emission coefficient σ of the cathode target 4d is set to be smaller than 1. Therefore, due to the impact of the electron beam,
The anode target 3e is positively charged and its potential increases, and the cathode target 4d is negatively charged and its potential decreases.

Therefore, there is an anode strip 1e between the anode strip 1e and the cathode strip 2d, which are exposed to the impact of the electron beam.
A voltage is generated such that If this voltage is sufficiently high, electrons are emitted from the needle electrode 5d by a field emission phenomenon and enter the anode band wire 1e, and the charges on the anode target 3e and the cathode target 4d disappear. At this time, the anode strip wire 4d made of a phosphor film is bombarded with electrons from the needle electrode 5d, so it emits visible light, and the anode strip wire 1e of the targets 3e and 4d, which are bombarded by the electron beam, emit visible light.
One pixel is given to the orthogonal point between and the cathode band line 2d.

Therefore, by scanning the anode target and the cathode target with the electron beams from the anode electron gun 6 and the cathode electron gun 7, respectively, and making the portions of all the anode strips facing the cathode strips emit light, the desired target can be obtained. An image is obtained.

In the conventional device configured as described above, the anode targets 3a to 3d and the cathode targets 4a to
4e is transferred to the needle electrode 5 during one scanning cycle.
need to be discharged by field emission electrons.

However, in a normal vacuum, for example on the order of 10 ^-7 Torr, the field emission electron flow from the needle electrode 5 is not large enough to discharge the charges stored in these targets 3a to 3d and 4a to 4e. As a result, the phosphor films on the anode strip wires 1a to 1f do not emit light at a predetermined brightness, resulting in disadvantages such as an extremely large amount of flicker noise in the image.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and after multiplying the field emission electron flow from the needle-like cathode using an electron multiplier, the field emission electron flow is made to enter the anode strip wire, and the anode An object of the present invention is to provide an image display device capable of displaying an image with small flicker noise by completely discharging the charges stored in a target.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a perspective view of an image display device according to the present invention.

In the figure, 1 is an anode strip wire, which is made of a metal thin film on a striped phosphor film, 2 is a striped cathode strip wire, and 3 is an anode target connected to the anode strip wire 1, which is made of copper beryllium. 4 is a cathode target connected to the cathode band wire 2, which is configured to collect most of the incident electrons; 5 is a cathode band line 2 perpendicular to the anode band line 1
Needle-shaped cathodes for field emission are provided at each point above, and the tip of a thin tungsten wire is made into a needle shape by electrolytic polishing. 6 is an anode electron gun for bombarding the anode target 3 with electrons. 7 is a cathode target. 4 is a cathode electron gun for electron bombardment, and 11 is an electron multiplier for multiplying the field emission electrons emitted from the needle cathode 5, for example, a secondary electron multiplier plate. As shown, each needle cathode 5 has an operating hole 1 at a corresponding position.
5 is provided.

Here, the performance required of the electron emitter of the image display device of the present invention is basically to emit the required amount of electrons when the turn of operation comes around, that is, to emit the required amount of electrons when the corresponding anode target 3 and When the cathode target 4 is bombarded with electrons by the respective electron guns 6 and 7, and the electron emitter is negatively charged and the anode strip wire facing it is positively charged, the electron emitter neutralizes the positive charge on the anode strip wire. In the present invention, since the electrons from the electron emitter are multiplied by the electron multiplier 11, the amount of emitted electrons can be extremely small, and the field emission needle-shaped A small electron emitter such as the cathode 5 can be used.

FIG. 4 shows a linear expansion of the relationship between the elements described above, where the same symbols as in FIG. 3 indicate the same elements, and 12 collects the secondary electrons emitted from the anode target 3 Anode collector for 1
3, 14, and 15 are power supplies.

Note that the anode collector 12 and power supplies 13, 14, and 15 are omitted in FIG.

Next, FIG. 3 shows the operation of the image display device of this invention.
This will be explained using FIG.

An appropriate deflection device (not shown) is used to scan the electron beam emitted from the anode electron gun 6 so as to sequentially impact the anode target 3, and the electron beam from the cathode electron gun 7 to impact the cathode target 4 sequentially.

In this case, the anode target 3 receiving the impact of the electron beam and the anode strip wire 1 connected thereto, and the cathode target 4 and the cathode strip wire 2 connected thereto have a configuration as shown in FIG.

In this case, the secondary electron emission coefficient of the anode target 3, that is, the ratio σ of the secondary electron flow to the primary (incident) electron flow, is made larger than 1 by appropriately selecting the material and the energy of the impact electrons. . For example, since the anode target 3 of this invention uses a copper-berium alloy, the energy of impact electrons is
At 500 to 1000 electron volts, the anode target 3 becomes positively charged depending on the amount of electricity chosen by the electron beam that bombards it.

Here, the anode collector 12 is connected to the anode target 3
The amount of positive charge corresponding to the potential of the anode collector 12 is accumulated in the anode target 3, and the amount of positive charge can be maintained at an appropriate value by setting the potential. .

On the other hand, since the cathode target 4 collects most of the electron beam from the cathode electron gun, it becomes negatively charged according to the amount of electricity, and its potential decreases.

Here, the secondary electrons emitted from the cathode target 4 are very small and are collected by other nearby electrodes, so there is no need to provide a collecting collector on the cathode target 4 side.

As is clear from FIG. 4, between the needle cathode 5 and the electron multiplier 11, there is a positive potential from the power supply 14 applied to the electron multiplier 11 and a negative potential formed on the cathode target 4. A voltage corresponding to the sum of absolute values is generated. Here, only the acicular cathode 5 on the cathode band wire 2 that connects this voltage to the cathode target 4, which is bombarded with electrons by the cathode electron gun 7, emits electrons, and the acicular cathodes on the other cathode band wires emit electrons. If the value is set high enough not to emit electrons, the electrons emitted from the needle cathode 5 are multiplied by the electron multiplier 11 and directed toward the anode strip wire 1. In this case, if a thin tungsten wire tip sharpened to a radius of curvature of 0.1 micron or less is used as the needle cathode 5, then when a voltage of 4.5 KV is applied to the electron multiplier 11 1 mm away from the tip, the needle cathode Electrons in the range of 5 to 10 ^-8 amperes are emitted, and almost no electrons are emitted at 4.0 KV.

Therefore, when using the needle cathode 5 as described above, it is appropriate that the power source 14 of the electron multiplier 11 be 4KV. As the electron multiplier 11, a secondary electron multiplier plate made of lead glass may be used. For example, if a hole diameter of 0.1 mm and a thickness of 4.0 mm is operated with a power supply voltage of 1 KV, the multiplication factor will be approximately 10 ⁴ , and the electrons emitted from one needle cathode 5 will be 10 ^-4 amperes. is multiplied by Among the multiplied electrons heading toward the anode strip wire 1, only those heading toward the anode strip wire 1 connected to the anode target 3 bombarded with electrons by the anode electron gun 6 impact the anode strip wire 1; A phosphor film provided thereon emits light to form one pixel. The remaining electrons then return to the electron multiplier 11.

In this case, the luminance of the phosphor film is determined by the amount of charge stored in the anode strip wire 1. because,
The luminance of the phosphor is proportional to the product of the average impact electron flow during one scanning period and its energy, but in the above embodiment, the impact current is determined by the amount of charge stored in the anode band wire 1, and the impact The energy of the electron stream is supplied to two power sources 13 and 14 connected to the electron multiplier 11.
The voltage of the anode strip wire 1 is determined by the amount of charge stored in the anode strip wire 1, the stray capacitance of the anode strip wire 1, and the voltage of the anode strip wire 1 (with respect to ground), which is determined by the leakage resistance. Of the voltages at each of these parts, only the voltage at the anode band wire 1 changes, but since this is determined by the amount of stored charge, the energy of the impact electron flow is also determined by this amount of charge, and eventually the impact The product of electron flow and its energy is determined by the amount of charge stored in the anode strip wire 1. Therefore, by controlling the amount of charge, the luminance of the phosphor film provided on each anode strip wire 1 can be controlled. This amount of charge is controlled by the anode target 3.
This can be done by using the electron beam current of the anode electron gun 6 that bombards the electron beam.

When displaying an image in the image display apparatus of the present invention as described above, the electron beam from the anode electron gun 6 is used to target the anode target 3, and the electron beam from the cathode electron gun 7 is used to target the cathode target 4.
It is sufficient to modulate the electron beam by sequentially scanning each of the electron beams and controlling the electron beam current from the anode electron gun 6 at the same time. In this embodiment, the electrons emitted from the acicular cathode 5 are multiplied using the electron multiplier 11 to create an electron flow that can sufficiently discharge the charge stored in the anode strip wire 1 during one scanning period. Therefore, the flickering noise that occurs in conventional image display devices of this type, which is caused by the fact that the electron flow emitted from the needle cathode 5 is small and the electric charge stored in the anode strip wire 1 cannot be sufficiently discharged, can be eliminated. Ru.

In the above embodiment, the needle-like cathode 5 is used as the electron emitting body in the cathode band wire 2, but as the electron emitting body, a device that emits electrons such as a hot cathode may be used in the cathode band wire 2. In this case,
If the hot cathode is constantly heated so that it can immediately emit electrons when a voltage is applied to it, even if it is an electron emitter that uses a heater and has a slow rise,
It is possible to perform high-speed operation that follows the scanning by the electron gun. Furthermore, when a hot cathode is used, the amount of electrons emitted from the hot cathode can be extremely small by using an electron multiplier, so that the heating power for the hot cathode can be small.

As described above, according to the present invention, the electron flow from the cathode band wire is multiplied by the electron multiplier and then made incident on the anode band wire to completely discharge the charge stored in the anode band wire. This has advantages such as the ability to obtain clear images without flicker noise.

[Brief explanation of the drawing]

Fig. 1 is a front perspective view of a conventional image display device, Fig. 2 is a linear developed view showing the relationship between each element of the conventional image display device, and Fig. 3 is a partially cutaway view showing an embodiment of the present invention. FIG. 4 is a linear development diagram showing the relationship between each element of an image display device according to an embodiment of the present invention. In the figure, 1 is the anode band line, 2 is the cathode band line, and 3 is the anode band line.
4 is an anode target, 4 is a cathode target, 5 is a needle electrode for field emission, 6 is an anode electron gun, 7 is a cathode electron gun, 8 is a vacuum vessel, 11 is an electron multiplier, 1
3, 14, and 15 are power supplies. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An anode strip wire group to which an anode target is connected and coated with a phosphor film; a cathode strip wire group to which a cathode target is connected and arranged perpendicular to the anode strip wire;
An electron emitter provided on the cathode band wire at all positions facing the anode band wire, and an anode electron gun and a cathode electron gun that sequentially bombard the anode target and the cathode target with electrons, respectively, and the anode The band wire is charged positively and the cathode band wire is charged negatively, and electrons are irradiated from the electron emitter to the phosphor film of the anode band wire, so that the phosphor film at a position facing the electron emitter is charged. An image display device configured to emit light sequentially, characterized in that an electron multiplier for multiplying electrons emitted from the electron emitter is provided between the electron emitter and the anode band wire group. Image display device.