Patent ID: 9363874
Filing Date: 2016-06-07
CPC Classification: H05B

Claim Text:
1. A current controlling device for controlling an electric field emission current in connection with an electric field emission device which emits electrons in response to an applied voltage, the current controlling device comprising: a first current controlling transistor defining a first current path in response to a first gate voltage, the first gate voltage being provided to a gate of the first current controlling transistor; a second current controlling transistor connected in series between the field emission device and the first current controlling transistor, the second current controlling transistor defining a second current path in response to a second gate voltage, the second gate voltage being provided to a gate of the second current controlling transistor; and a control logic controlling the first and second gate voltages, wherein the control logic controls an upper limit of the field emission current by using the first gate voltage, and wherein the control logic maintains the field emission current at a constant level when the field emission device is operating.