Thermometer for remotely measuring temperature
AssigneeNorman C. Anderson
InventorRobert E. Rupert
Life of this patent
Estimating the term…
Abstract
A thermometer is provided for remotely measuring the temperature of a heat source. The device utilizes an infrared sensor for detecting the temperature of a remote object and an output of the sensor is processed and used to drive a meter or other display device. An improved resonant circuit is provided for modulating the radiant energy impinging on the sensor to produce a pulsed output from the sensor. The modulating circuit includes a piezoelectric reed which deflects under an applied frequency and is located in the optical path of the system. The reed serves as an active element in an improved phase-locked loop used to drive and stabilize the optical chopper.
Claims6
An instrument for measuring the temperature of an object by means of the infrared radiation emitted therefrom, comprising
- (a) a radiation detector adapted to generate an electrical output in response to radiation impinging thereon,
- (b) means for forming and directing a beam of radiation against said detector,
- (c) temperature indicating means connected to said detector for converting the electrical output of said detector into a display representative of the temperature of said object,
- (d) beam modulating means disposed in the path of said beam for converting said beam into a series of pulses when vibrated in and out of said path,
- (e) said modulating means including a piezoelectric reed element adapted to vibrate when subjected to driving signals at a frequency related to the resonant frequency of said element, and,
- (f) phase locked loop oscillator circuit means connected to said reed element for operating said reed,
- (g) said element adapted to generate a reference signal when vibrated whereby said reference signal functions to lock said circuit means at the resonant frequency of said element.
A resonant circuit, comprising
- (a) a piezoelectric element adapted to vibrate when subjected to driving signals at a frequency related to the resonant frequency of said element, and
- (b) phase locked loop oscillator circuit means connected to said element for operating said element at its resonant frequency,
- (c) said circuit means including a voltage controlled oscillator, a phase comparator receiving signals from said oscillator and from said element and a filter receiving an output from said comparator and providing an input to said oscillator.
Dependencies are inferred from the claim text.