Optical chopper for infrared thermometer
AssigneeIVAC Corporation
InventorCharles E. Everest
Life of this patent
Estimating the term…
Abstract
The infrared thermometer optical chopper includes a planar shutter having infrared radiation transmissive and infrared reflective portions arranged on the shutter, and a mechanism for rotating the shutter sequentially through a series of stop positions in which the transmissive and reflective portions are sequentially aligned with the internal optics of the infrared thermometer. A mechanism is also preferably provided for sensing the positioning of the shutter at the stop positions, to determine whether the shutter stop position alignment is in an infrared radiation transmissive phase or in an infrared radiation reflective phase.
Claims38
In an infrared thermometer apparatus of the type having an infrared sensor and means in said thermometer for focusing infrared radiation on said sensor, the improvement in said thermometer of an optical chopper comprising:
- (a) a planar shutter having an axis of rotation, mounted for rotational movement through a plurality of stop positions adjacent and external to said means for focusing, having a first side facing said means for focusing and a second side, said shutter having equally spaced apart infrared radiation transmissive and non-transmissive portions, said non-transmissive portions of said first side having a reflective surface on at least a portion thereof;
- and
- (b) means for rotating said shutter sequentially through said plurality of stop positions corresponding to each of said transmissive and non-transmissive portions, such that each stop position is sequentially aligned with said means for focusing for either transmitting infrared radiation through said shutter or blocking transmission of substantially all external infrared radiation to said sensors and reflecting substantially all internal infrared radiation from said shutter to said sensor.
An infrared thermometer apparatus having an infrared sensor, means for focusing infrared radiation on said sensor, and an optical chopper comprising:
- (a) a planar shutter having an axis of rotation, mounted for rotational movement through a plurality of stop positions adjacent and external to said means for focusing, having a first side facing said means for focusing and a second side, said shutter having equally spaced apart infrared radiation transmissive and non-transmissive portions, said non-transmissive portions of said first side having a reflective surface on at least a portion thereof;
- and
- (b) means for rotating said shutter sequentially through said plurality of stop positions corresponding to each of said transmissive and non-transmissive portions, such that each stop position is sequentially aligned with said means for focusing for either transmitting infrared radiation through said shutter or blocking transmission of substantially all external infrared radiation to said sensor and reflecting substantially all internal infrared radiation from said shutter to said sensor.
An infrared thermometer apparatus comprising a housing, insulating means contained in said housing;
- heat sink means contained within said insulating means and surrounding an infrared sensor adapted to generate a signal indicative of infrared radiation received by said sensor;
- said sensor including means for measuring the temperature of said infrared sensor, means for focusing infrared radiation on said sensor;
- optical chopper means for controlling transmission of infrared radiation through said focusing means;
- and means for displaying a temperature reading operatively connected to receive said sensor signal;
- comprising:
- (a) a planar shutter having an axis of rotation, mounted for rotational movement through a plurality of stop positions adjacent and external to said means for focusing, having a first side facing said means for focusing and a second side, said shutter having equally spaced apart infrared radiation transmissive and non-transmissive portions, said non-transmissive portions of said first side having a reflective surface on at least a portion thereof;
- and
- (b) means for rotating said shutter sequentially through said plurality of stop positions corresponding to each of said transmissive and non-transmissive portions, such that each stop position is sequentially aligned with said means for focusing for either transmitting infrared radiation through said shutter or blocking transmission of substantially all external radiation from said sensor and reflecting substantially all internal infrared radiation from said shutter to said sensor.
Dependencies are inferred from the claim text.