Multi-electrode field emission device having single power source and method of driving same

Patent metadata

Field	Value
Publication number	US-9351350-B2
Application number	US-201414283755-A
Country	US
Kind code	B2
Filing date	May 21, 2014
Priority date	May 24, 2013
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A field emission device and a method of driving the multi-electrode field emission device having a single driving power source are disclosed. The field emission device includes a cathode electrode, one or more gate electrodes, a voltage division unit, and a power source unit. The cathode electrode is figured such that at least one emitter is formed thereon. The gate electrodes are disposed between an anode electrode and the cathode electrode, and each have one or more openings through which electrons emitted from the emitter can pass. The voltage division unit has one or more divider resistors, and divides a voltage applied from the power source unit using the divider resistors and then applies partial voltages to the one or more gate electrodes. The power source unit includes a single power source, and applies the voltage to the voltage division unit.

First claim

What is claimed is:

1. A field emission device, comprising:
an anode electrode;
a cathode electrode configured such that at least one emitter is formed thereon;
a power source unit including a single power source;
a voltage division unit, including two divider resistors connected in series, configured to divide a voltage applied from the power source unit using the two divider resistors to generate a partial voltage;
a gate electrode disposed between the anode electrode and the cathode electrode, the gate electrode having one or more openings through which electrons emitted from the at least one emitter pass, the gate electrode being electrically connected to a connection point at which the two divider resistors are connected, the partial voltage generated by the voltage division unit being supplied via the connection point to the gate electrode as a gate voltage; and
a current control unit electrically connected between the cathode electrode and the voltage division unit and configured to control a cathode current flowing through the cathode electrode for controlling the partial voltage.

2. The field emission device of claim 1 , wherein the current control unit comprises:
a control signal generation unit configured to input a control signal operative to control the cathode current; and
a current switching unit configured to selectively turn on and off the cathode current in response to the control signal.

3. The field emission device of claim 2 , wherein the control signal is a low voltage pulse signal or a direct current (DC) signal in a range of 0 to 5 V.

4. The field emission device of claim 2 , wherein
the current switching unit comprises a transistor configured such that the power source is connected to a source terminal thereof,
the cathode electrode is connected to a drain terminal thereof and
the control signal is input to a gate terminal thereof.

5. The field emission device of claim 2 , wherein the voltage division unit further comprises an additional divider resistor configured to divide the voltage applied from the power source unit and apply a partial voltage to the control signal generation unit.

6. The field emission device of claim 2 , wherein the control signal generation unit comprises a wireless communication unit, and receives the control signal from an outside via the wireless communication unit and inputs the control signal to the current switching unit.

7. The field emission device of claim 6 , wherein the single power source is a negative power source, and the anode electrode is grounded.

8. The field emission device of claim 2 , wherein values of the divider resistors are arbitrary values that meet both a first condition that a voltage applied to the gate electrode is higher than a minimum required gate voltage and a second condition that during current control of the current control unit, the cathode voltage is not higher than an allowable voltage of the current control unit.

9. The field emission device of claim 8 , wherein the values of the divider resistors are values that belong to the values meeting the first and second conditions and that maximize a sum of the resistance values of the divider resistors.

10. A field emission device comprising:
a cathode electrode configured such that at least one emitter is formed thereon;
one or more gate electrodes disposed between an anode electrode and the cathode electrode, and each configured to have one or more openings through which electrons emitted from the at least one emitter pass;
a power source unit including a single power source;
a voltage division unit including one or more divider resistors connected in series, configured to divide a voltage applied from the power source unit using the divider resistors and apply partial voltages to the one or more gate electrodes; and
a current control unit electrically connected to the cathode electrode and configured to control a cathode current flowing through the cathode electrode, the current control unit including
a control signal generation unit configured to input a control signal operative to control the cathode current, and
a current switching unit configured to selectively turn on and off the cathode current in response to the control signal, the current switching unit including
a variable resistor connected to a gate terminal of a first transistor and configured to control a voltage of the control signal input to a second transistor,
the first transistor configured such that the power source is connected to a source terminal thereof, a source terminal of the second transistor is connected to a drain terminal thereof and the variable resistor is connected to a gate terminal thereof, and
the second transistor configured such that the drain terminal of the first transistor is connected to the source terminal thereof, the cathode electrode is connected to a drain terminal thereof and the control signal whose voltage has been controlled by the variable resistor is input to a gate terminal thereof.

11. The field emission device of claim 10 , wherein the first transistor is a low voltage transistor, and the second transistor is a high voltage transistor.

12. A method of driving a field emission device that includes a single power source, a cathode electrode and an anode electrode, a voltage division unit, including a plurality of divider resistors, connected between the cathode and anode electrodes, a gate electrode electrically connected to a connection point at which two of the divider resistors are connected, and a current control unit electrically connected between the cathode electrode and the voltage division unit, comprising:
applying a voltage to the voltage division unit using the single power source;
dividing, by the divider resistors, a voltage applied from the single power source to generate a partial voltage, and applying, by the voltage division unit, the partial voltage via the connection point to the gate electrode as a gate voltage; and
controlling, by a current control unit, a cathode current flowing through the cathode electrode for controlling the partial voltage to be supplied to the gate electrode as the gate voltage.

13. The method of claim 12 , wherein setting the resistance values of the divider resistors comprises:
calculating values that meet both a first condition that a voltage applied to the gate electrode is higher than a minimum required gate voltage and a second condition that during the current control of the current control unit, the cathode voltage is not higher than the allowable voltage of the current control unit; and
selecting arbitrary values from among the calculated values.

14. The method of claim 13 , wherein selecting the arbitrary values comprises selecting values that belong to the values meeting the first and second conditions and that maximize a sum of the resistance values of the divider resistors.

15. The method of claim 12 , wherein controlling the cathode current includes generating a control signal that is a low voltage pulse signal or a direct current (DC) signal in a range of 0 to 5 V to control the partial voltages to be supplied to the gate electrode as the gate voltage.

16. The method of claim 12 , further comprising
setting the single power source to a negative power source and connecting the anode electrode to ground,
wherein setting the resistance values of the divider resistors comprises receiving, by the current control unit, a control signal from an outside via wireless communication, and setting the resistance values using the received control signal by controlling the cathode cu

Assignees

• Korea Electronics Telecomm

Inventors

• Jeong Jin-Woo
• Song Yoon-Ho
• Kim Jae-Woo
• Kang Jun-Tae

Classifications

• H01J1/304 Primary

  Field-emissive cathodes · CPC title

• H05B33/08 Primary

  Electricity · mapped topic

• H01J3/021

  Electron guns using a field emission, photo emission, or secondary emission electron source · CPC title