JPS62272438A - Electron emitting device - Google Patents

Abstract

PURPOSE:To stably obtain the quantity of electron emission to the change in an outer environment and in characteristics of an electron emitting element or the like by maintaining the quantity of the electron current indirectly measured by the calculated difference between the in-flow and out-flow currents of the electron emitting element to be constant. CONSTITUTION:A voltage V1 is applied to an electron emitting element 11 in a variable voltage circuit 14 so that a constant voltage V2 is applied to an anode 15. Then, the currents I0, I1 and I2 flow. A voltage is generated on both ends of resistances R0 and R1 by the currents I0, I1 and I2 and inputted into an amplifier 18 through amplifiers 16, 17. In the case of the resistance R0=R1=R2, the output from the amplifier 18 is to be the value corresponding to the difference between currents 10 and 11, which is the indirectly measured value of the electron emitting quantity. The voltage V1 is adjusted in such a manner that said measurement value is compared with the set value by an amplifier 19 and the difference is made to be small. Therefore, it is possible to maintain the electron emitting quantity to the desired set value without reference to the change in enviroment and in efficiency of the element 11.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electron-emitting device, and particularly relates to an electron-emitting device that emits electrons by applying a voltage, and an electron-emitting device that emits electrons by applying a voltage. The present invention relates to an electron emitting device having a seven-node electrode.

[Prior Art] A conventional electron-emitting device uses various electron-emitting elements as described below, and generates an electron flow by attracting electrons emitted from the elements to a seven-node electrode.

The electron-emitting devices used include those that use avalanche breakdown of a PM junction, those that apply a forward bias to the PM junction and inject electrons into the P layer, and those that have a structure in which a thin insulating layer is sandwiched between metal layers. (MIX type), field emission type and surface conduction type elements have been proposed.

Figure 2 (A) shows that the PM junction is forward biased and P
FIG. 2B is a schematic explanatory diagram of an electron-emitting device that injects electrons into a layer, and FIG. 2B is a graph showing a schematic current-voltage characteristic thereof.

In the figure (A), when a bias voltage V in the forward direction of the PM to be bonded is applied, a forward current I as shown in the figure (B) flows, and the electrons injected from the NM into the P layer are transferred from the P layer surface. Released into vacuum. The surface of this P layer is coated with cesium Cs or the like in order to lower the work function and increase the amount of electron emission.

FIG. 3 is a schematic diagram of a diagonal type electron-emitting device, and FIG. 4 is a schematic diagram of a surface conduction type electron-emitting device.

MIX type electron emitting device metal electrode 1. It has a structure in which an insulating layer 2 and a thin metal electrode 3 are laminated, and the electrode! By applying a voltage between 3 and 3, electrons are emitted from the thin electrode 3 side.

Further, in the surface conduction electron-emitting device, electrodes 5 and B are formed on an insulating substrate 4, and a high-resistance thin film 7 is formed between them. Then, by applying a voltage between the electrodes 5 and 8, electrons are emitted from the surface of the high-resistance thin film 7.

FIG. 5 is a schematic diagram of a conventional electron-emitting device.

As shown in the figure, a voltage v1 is applied to the electron-emitting device 8 as described above, and the electrons emitted thereby are attracted to the seven-node electrode 3 to which a voltage v2 is applied, forming an electron flow.

[Problems to be Solved by the Invention] However, in such conventional electron-emitting devices, the amount of electrons emitted changes due to changes in the external environment, changes in element efficiency, etc., and it is difficult to obtain a stable electron flow. There wasn't.

In particular, as shown in the same figure (B), when the applied voltage V exceeds Vf, the current! The change in the amount of electrons increases, making it difficult to stabilize the amount of electron emission.

Furthermore, when MIX type and surface conduction type electron-emitting devices are used, as in the case of the PM type described above, when the applied voltage exceeds a certain level, the current changes greatly, making it difficult to stabilize the electron flow. there were.

Furthermore, since the amount of electron emission changes due to changes in the external environment, changes in element efficiency, etc., it has been impossible to obtain a stable electron flow.

This instability of the electron flow is the same even when W is used in an element utilizing PM bonded avalanche breakdown or a field emission type element.

Also, cesium Cs is applied to lower the work function.
is an unstable element and causes changes in the amount of electron emission.

[Means for Solving the Problems] An electron-emitting device according to the present invention has a structure in which electrons emitted from an electron-emitting element are attracted to a seven-node electrode, and the electron-emitting device has the following features: an inflow current to the electron-emitting element and current detection means for detecting each outflow current from the electron-emitting device; arithmetic means for calculating the difference between the inflow current and outflow current; based on the difference between the inflow current and outflow current, and voltage control means for adjusting the voltage applied to the device.

[Operation] The difference between the inflow current and the outflow current in the electron-emitting device corresponds to the amount of electron flow emitted from the electron-emitting device. For example, in FIG. 5, the outflow current 1o, the inflow current! 1, the current ■2 representing the amount of electron flow emitted from the electron-emitting device 8 is: 12 = Io −1
1. Therefore, the amount of electron flow can be indirectly measured by calculating the difference between the outflow and inflow currents, and the applied voltage is adjusted to maintain the difference at a desired constant value. By making the adjustment, it is possible to always obtain a stable amount of electron emission even if the characteristics of the external environment or the electron-emitting device change.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an electron emitting device according to the present invention.

The electron-emitting device 11 in this embodiment is a PN junction type,
Any MIX type, surface conduction type, or field emission type may be used as long as the amount of electron emission can be controlled by the applied voltage. Here, as an example, a PM junction type electron-emitting device to which j forward bias is applied is used.

Electron-emitting device 11 has electrodes 12 and 13, and electrode 1
2 is an electrode from which current IO flows out, and electrode 13 is an electrode from which current IO flows out.
1 is the inflow electrode. The electrode 12 is a resistor R.

is connected to the negative electrode of the variable voltage circuit 14 through the electrode 1
3 is connected to the positive electrode of the variable voltage circuit 14 via a resistor R1. Further, the electrons 14 emitted from the electron-emitting device 11 are attracted to the seven-node electrode 15 to which voltage v2 is applied, resulting in a current {circle around (2)} representing the amount of electron flow.

Both ends of the resistors Ro and R1 are connected to operational amplifiers 1B and 17, respectively, the output terminal of operational amplifier 16 is connected to the non-inverting input terminal of operational amplifier 18, and the output terminal of operational amplifier 17 is connected to the inverting input terminal of operational amplifier 18. There is. The output terminal of the operational amplifier 18 is connected to the inverting input terminal of the operational amplifier IS, and a desired set value is input to the non-inverting input terminal. The output terminal of the operational amplifier 19 is connected to the control terminal of the variable voltage circuit 14, and the voltage v1 of the variable voltage circuit 14 is adjusted by the output of the operational amplifier 19.

Next, the operation of this embodiment having such a configuration will be explained.

First, a voltage v1 is applied to the electron-emitting device 11 by the variable voltage circuit 14, and a constant voltage v2 is applied to the seven-node electrode 15, so that the current 10.1 is applied as described above.
1 and I2 are flowing.

At this time, the voltage across each of the resistors Re and R is 1o Ro
and 1. R, is input to operational amplifier 18 via operational amplifiers 1B and 17, respectively. KokoteRo
= Rt = R, the output of the operational amplifier 1B is IGRo - It Rt = R (Io - It), and the current! This is a value corresponding to the difference between 0 and 11, that is, an indirect measurement value of the amount of electron emission. The output of the operational amplifier 18, which is the measured value of the amount of electron emission, is the output of the operational amplifier 19.
It is input to the inverting input terminal of , and is compared with the setting value input to the non-inverting input terminal. and.

The voltage v1 of the variable voltage circuit 14 is adjusted so as to reduce the difference between the measured value and the set value. Thereby, the amount of electron emission can be maintained at a desired set value regardless of changes in the environment, changes in the efficiency of the electron-emitting device, and the like.

In this embodiment, control was performed by changing the voltage v1, but it is also possible to change both the voltages v1 and v2 in the same way, and this adjustment is the easiest to control in consideration of the characteristics of the electron-emitting device 11, etc. All you have to do is decide on a method.

[Effects of the Invention] As explained above in detail, the electron-emitting device according to the present invention indirectly measures the amount of electron flow by calculating the difference between the outflow current and the inflow current in the electron-emitting element, and In order to adjust the voltage applied to the electron-emitting device so as to maintain the measured value at a desired constant value, it is possible to always obtain a stable amount of electron emission even if changes in the external environment or characteristics of the electron-emitting device occur. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an electron-emitting device according to the present invention. Figure 2 (A) is a schematic explanatory diagram of an electron-emitting device that injects electrons into two layers by applying a bias in the IIIR direction at PH1, and Figure 2 (CB) shows its general current-voltage characteristics. 3 is a schematic block diagram of a MIX type electron-emitting device, FIG. 4 is a schematic block diagram of a surface conduction type electron-emitting device, and FIG. 5 is a schematic diagram of a conventional electron-emitting device. FIG. 11... Electron-emitting device 14... Variable voltage circuit 15... Anode electrodes 1B to 18... Operational amplifier

Claims (1)

[Claims] (1) In an electron-emitting device having a configuration in which electrons emitted from an electron-emitting element are attracted to an anode electrode, a current detecting means for detecting an inflow current to the electron-emitting element and an outflow current from the electron-emitting element, respectively; , a calculation means for calculating the difference between the inflow current and the outflow current, and a voltage control means for adjusting the voltage applied to the electron-emitting device based on the difference between the inflow current and the outflow current. Characteristic electron emitting device.