Patent ID: 9606003
Date: 2017-03-28
CPC Classifications: G01J

Claim:
1. An apparatus adapted to be held in a user's hand for measuring, from a range of measurement distances from a surface, the temperature of a measured area of the surface, the apparatus comprising: a main housing having a main aperture partially defining an apparatus field of view; a detector within the main housing for measuring infrared energy entering the housing via the main aperture, and having a sensitive area for detecting infrared energy entering the main housing; means within the main housing for generating, outside the housing and at a distance from the main aperture, an optical image of the sensitive area having substantially the same shape as the sensitive area of the detector; and a limiting aperture defined within the main housing between the measured area and the generating means, and having approximately the same size and shape as the optical image, there being defined axially between the optical image and the limiting aperture an imaginary column having a lateral size corresponding generally to the size of the optical image; wherein infrared energy originating at the surface within the column passes through the limiting aperture to strike the sensitive area, and the limiting aperture prevents infrared energy not originating at the surface within the column from striking the sensitive area, wherein further a size of the measured area of the surface remains approximately constant notwithstanding changes in a distance between the measured area and the main aperture.