Resources Contact Us Home
Noncontact temperature measuring device

Image Number 6 for United States Patent #4456390.

A portable, battery operated noncontact temperature measuring device including a lens for collecting infrared radiation and a thermopile for producing a signal indicative of the intensity thereof. The thermopile signal is amplified, linearized and summed with an ambient temperature signal derived from a temperature responsive element, e.g. a diode chip mounted immediately adjacent a cold junction of the thermopile. The resulting composite temperature signal is then processed and displayed. The ambient temperature signal is also utilized to control the impedance of a dual field effect transistor, which in turn controls the gain of the amplifier. Thus, temperature induced variations in the responsivity of the thermopile are compensated by corresponding changes in the gain of the amplifier. An adjustable high impedance bias circuit provides bias current to the input of the amplifier, insuring that the signal at the output of the amplifier will not be affected by temperature induced changes in the internal resistance of the thermopile. A switching circuit alternately connects the output of the thermopile and a resistor having a resistance approximately equal to the internal resistance of the thermopile to the input of the amplifier. When the resistor is so connected, an automatic zeroing circuit reduces the amplifier output to approximately zero, thereby essentially eliminating amplifier drift.

  Recently Added Patents
Methods and systems for time-shifting content
Tungsten barrier and seed for copper filled TSV
Method for producing a sulfonated polyarylether block copolymer
Synchronous rectifier network unit circuit and method
Scanning transmission electron microscope and axial adjustment method thereof
Defected ground plane inductor
Device, information processing method, and computer-readable storage medium
  Randomly Featured Patents
Data carrier with an optically variable element
Semiconductor processing methods of forming a contact opening to a semiconductor substrate
System and method for extending the drag function of a computer pointing device
Method and apparatus for controlling deposition process using residual gas analysis
Vulnerability assessment of disk images
Apparatus and method for controlling data transmission
Life preserver storage container
Anchorable urethane foams
Ultrasonic flossing device
Self-learning integrity management system and related methods