Method and apparatus for providing output indications in response to the presence of an electromagnetic energy receptor
AssigneeELT, Incorporated
InventorJohn Fajt
Life of this patent
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Abstract
A method and apparatus for providing output indications in response to the presence of an electromagnetic energy receptor within a predetermined distance of a glow discharge device the electrodes of which have a voltage applied thereacross at least equal to the maintaining voltage but less than the breakdown voltage, including an excitor for generating an electromagnetic field around the glow discharge device at a strength less than the ionization level but sufficient to ionize the gas when the electromagnetic energy receptor is within the predetermined distance of the glow discharge device.
Claims7
Proximity sensing apparatus comprising:
- a glow discharge device having a pair of electrodes and an inert gas disposed between the electrodes, the gas allowing current to flow through the glow discharge device when the gas is in an ionized state, the gas being ionized when a voltage applied across the electrodes is at least equal to a predetermined breakdown voltage, and remaining in the ionized state so long as the voltage applied across the electrodes is at least equal to a predetermined maintaining voltage;
- a power supply connected to the glow discharge device, the power supply applying a voltage across the electrodes at least equal to the maintaining voltage but less than the breakdown voltage;
- and
- pulse generating means for applying a pulsed signal to each of said electrodes, said pulsed signal having a predetermined frequency from at least about 60 Hz and an amplitude from at least about 1500 volts selected to induce ionization of the inert gas in the glow discharge device when a mass is located within a predetermined positive distance of the glow discharge device, whereby current flow through the glow discharge device provides an output indication in response to the presence of the mass within the predetermined distance.
A method for providing an output indication in response to the presence of a mass within a predetermined distance of a glow discharge device having a pair of electrodes and an inert gas disposed between the electrodes, the method comprising the steps of:
- applying a voltage across the electrodes less than a predetermined breakdown voltage at which the gas will ionize to allow current flow through the glow discharge device, but at least equal to a predetermined maintaining voltage at which the gas will remain ionized;
- and,
- applying a pulsed signal to each of the electrodes, said pulsed signal having a pedetermined frequency from at least about 60 Hz and an amplitude from at least about 1500 volts selected to induce ionization of the gas in the glow discharge device when the mass is located within the predetermined distance of the glow discharge device, whereby current flow through the glow discharge device provides an output indication in response to the presence of the mass within the predetermined distance.
A method for providing an output indication in response to the presence of a mass within a predetermined distance of any one of a plurality of cold cathode diodes, each cold cathode diode having only a pair of electrodes and an inert gas disposed between the electrodes, the method comprising the steps of:
- applying a voltage across the electrodes of each of the cold cathode diodes, the voltage being less than a predetermined breakdown voltage at which the gas disposed in each of the cold cathode diodes will ionize to allow current flow through the respective cold cathode diode, but at least equal to a predetermined maintaining voltage at which the gas will remain ionized;
- and
- applying a pulsed signal to each of the electrodes of each of the cold cathode diodes, the pulsed signal having a predetermined frequency from at least about 60 Hz and an amplitude from at least about 1500 volts selected to induce ionization of the gas in a respective one of the cold cathode diodes when the mass is located within the predetermined distance of the respective cold cathode diode, whereby current flow through the respective cold cathode diode provides an output indication in response to the presence of the mass within the predetermined distance of the respective cold cathod diode.
Dependencies are inferred from the claim text.