KR20070071782A - The current and voltage measurement method of using a hall sensor in electron gun sub-power - Google Patents

Abstract

A method for measuring current and voltage of an auxiliary power source of an electron gun by a hall sensor is provided to stably operate the electron gun by preventing a short circuit, and to decrease complexity of a circuit by adopting a direct measurement method. A method for measuring current of an auxiliary power source(15) connected between a cathode(30) and a filament(20) in an electron gun measures the current by disposing a hall sensor(60) on a lead wire for connecting the cathode and the auxiliary power source. The hall sensor has a digital display device(70) for digitally displaying the measured current. A control unit generates a current restriction signal according to a measured current value and keeps the current value applied from the auxiliary power source to a load, below a predetermined value by feeding back the current restriction signal to the auxiliary power source.

Description

Current and voltage measurement method using Hall sensor of electron gun auxiliary power supply {THE CURRENT AND VOLTAGE MEASUREMENT METHOD OF USING A HALL SENSOR IN ELECTRON GUN SUB-POWER}

1 is a schematic diagram of a general high voltage electron gun internal structure;

2 is a view showing an example of a method for measuring the voltage and current of the electron gun auxiliary power supply using the Hall sensor according to the present invention;

Figure 3 is a view showing the connection state and the principle of the conductor shown in Figure 2 to measure the voltage and current of the electron gun auxiliary power supply by the Hall sensor according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: main power source, 15: auxiliary power source, 20: filament, 30: cathode, 40: anode, 60: hall sensor, 70: display device, 110: lead wire, 113: magnetic core, 115: hall device

The present invention is a method for measuring the current and voltage in the circuit of the electron gun power supply device, and more specifically, by measuring the voltage and current accurately and safely in the ion shock circuit of the electron gun power supply device, the stable control and operation technology of the electron gun system It is to provide a method for securing.

In general, an electron gun refers to a device for generating an electron beam in an electron tube such as a cathode ray tube or an electron microscope. It consists of a cathode that emits electrons and a focusing system that accelerates and produces an electron beam. Thermoelectron radiation is commonly used for cathodes, but field emission is also used for special applications such as high resolution electron microscopes.

Acceleration and focusing meters vary depending on the application and are largely divided into small currents of less than 1 mA (milliamperes) such as CRT and electron microscopes, and large currents used for microwave tubes. The electron gun of the CRT represents a cathode ray tube, which uses a heat-dissipating cathode coated with an oxide on a nickel base. The first electrode controls the electron beam with an electrical signal, and the second electrode is followed. This forms a triode and at the same time forms a first lens.

The second and third electrodes are formed to form a prefocus lens, and are then connected to the third and fourth (or third, fourth and fifth) electrodes constituting the second lens to form an electron gun as a whole. . A small spot is caused by bombarding the electron beam with the formed electron gun and colliding with the fluorescent surface.

The structure of the large-capacity electron gun is described below with reference to FIG. 1.

As shown in FIG. 1, electrons generated in the filament 1 are accelerated to a voltage of about 1 kV to 2 kV to heat the block cathode 2. Electrons generated at the cathode are accelerated toward the anode 3 in the high voltage range.

Here, the focusing coil 4 and the deflection coil 5 for adjusting the position of the electron beam on a plane perpendicular to the electron beam traveling direction are provided in one body to adjust the diameter of the electron beam. In addition, in order to increase the current density of the electron beam, the strength of the electric field must be large at the front of the cathode, thereby shortening the gap between the cathode and the anode.

The average life of the cathode 2 is mainly dependent on the evaporation of the cathode surface due to heating and the extent to which the metal ions accelerated in the opposite direction to the traveling direction of the electron beam hit the cathode surface and cause physical damage.

In order to stably operate and control electron guns of various capacities as described above, stable control of the power supply device is essential. For stable control of such a power supply device, it is necessary to measure voltage and current accurately and stably in order to apply a high voltage between the heating wire (filament) and the cathode plate (cathode) inside the electron gun.

In particular, in the measurement of the voltage and current of the ion bombardment power source applied as the main auxiliary power source in the 30 kW high-capacity, high-voltage electron gun power supply device, the ion shock circuit has no grounding and high voltage is applied. This is necessary.

In other words, connect the current transformer directly in series with the conductor to measure the ion bombardment voltage and current. In the operation of the ion shock circuit, the current flowing through the circuit operates the current transformer to obtain an output signal from the current transformer, and measures the output signal of the current transformer by comparing the output signal of the current transformer with a reference value from an external source.

However, as an indirect measuring method to measure compared with a reference signal, the reference value must be input and compared, so that not only the occurrence of error is large, but also has a disadvantage in that the configuration of the measurement circuit is complicated. In addition, since the current transformer is directly connected to the conductor, there is a risk of short circuit accident, which requires attention to the insulation work, it is difficult to operate the electron gun stably.

The technical problem to be solved by the present invention is to provide a method for measuring the current and voltage of the electron gun auxiliary power supply according to the present invention, there is no risk of short circuit in a non-contact measuring method, it is possible to operate the electron gun stably In addition, the direct measurement method can reduce the complexity of the circuit to a large extent, and there is no error in the output of the measured value by comparison with the reference value, thereby allowing more accurate and accurate measurement.

According to a first aspect of the present invention, there is provided a current measuring method for measuring a current of an auxiliary power source connected between a cathode and a filament in an electron gun power supply, wherein a hall sensor is positioned on a wire connecting the cathode and the auxiliary power source. It is characterized by measuring the current.

In addition, the Hall sensor preferably includes a digital display device capable of digitally displaying the measured current, and generates a current limit signal according to the current value measured by the Hall sensor, the generated current limit signal It is also preferable to include a control means for feeding back to the auxiliary power supply to control the current value applied from the auxiliary power supply to the load to a predetermined value or less.

According to a second aspect of the present invention, there is provided a voltage measuring method for measuring a voltage of an auxiliary power supply connected between a cathode and a filament of an electron gun power supply, wherein the voltage is measured by placing a Hall sensor on a conductor connected in parallel with the auxiliary power supply. It is characterized by.

In addition, the Hall sensor preferably includes a digital display capable of digitally displaying the measured voltage, and generates a voltage limit signal in accordance with the voltage value measured by the Hall sensor, the generated voltage limit It is also preferable to include a control means for feeding back a signal to the auxiliary power supply and controlling the voltage value applied from the auxiliary power supply to the load to a predetermined value or less.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the voltage and current measurement method of the electron gun auxiliary power supply using the Hall sensor according to the present invention.

2 is a view showing an example of a method for measuring the voltage and current of the electron gun auxiliary power supply using the Hall sensor according to the present invention. As shown in FIG. 2, the electron gun has a main power source 10 for applying a voltage between the cathode 30 and the anode 40, and for increasing the output efficiency of the electron beam between the cathode 30 and the filament 20. It includes a power supply device formed of the auxiliary power source (15).

Here, hall sensors 60 and 100 are installed in contact with the conductive wires to measure voltage and current of the auxiliary power supply 15. That is, it installs so that a conductor may pass through a hole. Since there is a space between the lead wire and the hole, it is non-contact, which can completely prevent a short circuit accident. In addition, since the sensor directly detects the magnetic field generated by the current flowing through the wire and detects the voltage and current values, it is possible to eliminate the occurrence of measurement error.

FIG. 3 is a view illustrating a connection state 100 and a principle thereof with the conductive wire shown in FIG. 2 to measure the voltage and current of the electron gun auxiliary power supply by the Hall sensor according to the present invention.

Referring to the principle and advantages of the Hall sensor in more detail with reference to Figure 3, the hall sensor (hall sensor) 100 is a voltage and current sensor having a good response to convert the strength of the current magnetic field to a voltage. As shown in FIG. 3, the structure of the hall sensor is formed by arranging the magnetic core 113 and installing the Hall element 115 between the gaps.

First, the Hall Effect, which is the basic principle of Hall sensors, was described. The Hall Effect was discovered in 1879 by American physicist E. H. Hall. When a solid such as a metal or a semiconductor is placed in a magnetic field and a current flows in the solid at a right angle to the direction of the magnetic field, an electric field appears in the solid at a right angle in each of the two directions. This is called electromotive force. When charged particles (for example, electrons) move in a magnetic field, the direction of movement is bent under the force of Lorentz. Therefore, the electric field appears because the current flow in the solid is biased to one side and the distribution of charges is unbalanced.

In addition, even in the same direction, the direction of the electric field generated by the negative and positive charge (the electron is negative) is different, and the intensity of the electric field varies depending on the particle concentration. This effect is used to measure the concentration or mobility of electrons (especially called free electrons) that carry current in a solid, and in particular in semiconductors, identifying and measuring free holes with free electrons. You can also

By the Hall effect, the induced electromotive force (hole electromotive force) Vh which is proportional to the current I flowing on the conductive line 110 can be measured with high sensitivity, and the voltage and the current can be measured from the electromotive force. Hereinafter, the measuring principle will be described in detail.

When current (direct current, alternating current, direct current + alternating current) I flows through the bus line 110, a magnetic flux B proportional to the current I is generated in the gap, and penetrates perpendicularly to the hole element surface. In this state, when the control current Ic flows in a direction perpendicular to the magnetic flux B of FIG. 3, a voltage Vh proportional to the bus current I is generated between the terminals a-b.

The Hall sensor has a Hall voltage V _h of a few tens of mV, but an amplifier may be used to amplify its output. The hall voltage is output by the following equation.

V _h = K * Ic * B ----------------------- Formula (1)

(Vh: Hall voltage, K: sensitivity constant, Ic: control current, B: magnetic flux density)

As described above, the Hall sensor 100 may measure first, direct current, alternating current, direct current + alternating current, and secondly, contact the semiconductor 115 to be measured to be completely insulated. Third, there is no power loss, fast response characteristics, excellent straightness, simple structure and good reliability.

As shown in FIG. 2, the hall sensor 100 measures the current by placing the hall sensor in a non-contact manner on a conductor connecting the cathode and the auxiliary power source 15. The connection 100 of the conductive wire and the hall sensor is shown in detail in FIG. 3.

In order to measure the current of the electron gun auxiliary power source, in the related art, a method in which a current transformer is connected in series with a current transformer is used. As an auxiliary power source of the electron gun, a circuit for inducing an ion shock to increase the output efficiency of the electron beam is grounded. There is always a risk of short circuit accident due to high voltage.

However, according to the current measuring method proposed in the present invention, it can be connected to the conductor in a non-contact by using the Hall sensor, it is possible to measure the current stably without the risk of short circuit.

In the conventional measuring method using a current transformer, since a method of inputting a reference value and comparing the measured value with the measured value is outputted, there is a complexity in that a comparison circuit must be separately configured. Due to this, the accuracy of the measured output value is disadvantageous. However, if the current is measured by the method proposed in the present invention, the current can be measured more precisely and accurately by directly measuring the current without having to configure a comparison circuit.

Here, the Hall sensor 100 is configured to obtain an output converted to a voltage of 5V when a current of 2A flows in the conducting wire passing through the hall sensor to the center of the wire in which the DC high voltage of 1000V is applied. Is connected to the digital meta 70 to read the measured current value.

As such, the Hall sensor preferably includes a digital display 70 capable of digitally displaying the measured value. In general, the Hall sensor may use various types of display devices including a digital meta device and also include an ana-roll-to-digital converter. More accurate and accurate measurement.

In addition, a current limit signal according to the current value measured by the Hall sensor is generated, and the generated current limit signal is fed back to the auxiliary power supply, so that the current value applied from the auxiliary power supply to the load is set to a predetermined value. It is preferable to include a control means for controlling the following.

Such control means may be connected between the hall sensor and the auxiliary power supply, and may be constituted by a logic arc that sends a limit signal to the auxiliary power source so that the current value measured by the hall sensor does not exceed a predetermined value initially set.

In addition, as shown in FIG. 2, the Hall sensor 60 is positioned on a conductor connected in parallel with the auxiliary power source 15 to measure the voltage in the method of measuring the voltage of the auxiliary electron power supply device according to the present invention.

In this case, when the DC voltage of 1000 V is applied to the resistor, 20 mA flows, and when the hall sensor detects the 20 mA, the output is converted into a voltage of 1 V, and the output is converted into a digital meta (70). It is possible to read the digital signal by measuring the measured voltage value.

This voltage measurement method is also the same as the current measurement principle, and generates a current limit signal according to the voltage value measured by the Hall sensor 60, and feeds back the generated voltage limit signal to an auxiliary power supply. It is also preferable to include control means for controlling the voltage value applied from the auxiliary power supply to the load to a predetermined value or less.

The control means is connected by the Hall sensor 60 and the auxiliary power supply 15, and constituted by a logic arc that sends a limit signal to the auxiliary power supply so that the voltage value measured by the Hall sensor does not exceed a predetermined value initially set. It is also possible.

Thus, when using the method of measuring the current and voltage of the electron gun auxiliary power supply 15 according to the present invention, there is no risk of short circuit in the non-contact measuring method, it is possible to operate the electron gun stably, and also is a direct measurement method Not only can the complexity of the circuit be significantly reduced, but there is no error in the output of the measured value by comparison with the reference value, and thus, there is an advantage that more accurate and accurate measurement can be performed.

While the invention has been shown and described in connection with specific embodiments thereof, it is well known in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

As described above, by providing a method for measuring the current and voltage of the electron gun auxiliary power supply according to the present invention, since there is no risk of short circuit by the non-contact measuring method, the electron gun can be stably operated, and also the direct measurement method In addition to significantly reducing the complexity of the circuit, there are no errors in the output of the measured value compared to the reference value, allowing more accurate and accurate current and voltage measurements.

Claims (6)

In the current measuring method for measuring the current of the auxiliary power supply connected between the cathode and the filament in the electron gun power supply, And measuring a current by placing a hall sensor on a wire connecting the cathode and the auxiliary power source. The method of claim 1 And the hall sensor comprises a digital display capable of digitally displaying the measured current. The method according to claim 1 or 2, Generates a current limit signal according to the current value measured by the Hall sensor, and feeds back the generated current limit signal to the auxiliary power supply, so that the current value applied from the auxiliary power supply to the load is lower than a predetermined value. Current measuring method comprising a control means for controlling. In the voltage measuring method for measuring the voltage of the auxiliary power supply connected between the cathode and the filament of the electron gun power supply, And measuring a voltage by placing a hall sensor on a wire connected in parallel with the auxiliary power source. The method of claim 4, wherein And the hall sensor comprises a digital display capable of digitally displaying the measured voltage. The method according to claim 4 or 5, A voltage limit signal is generated according to the voltage value measured by the hall sensor, and the generated voltage limit signal is fed back to the auxiliary power supply, so that the voltage value applied from the auxiliary power supply to the load is lower than a predetermined value. Voltage measuring method comprising a control means for controlling.

Images