Infrared thermometer with fiber optic remote pickup
US4919505A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1989 |
| Grant date | Apr 24, 1990 |
| Priority date | — |
| Expiry date | Jan 12, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/3624
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An infrared thermometer (10) with a fixed aperture (99), focusable remote pickup head (12) conveys infrared light (16) from a target (14) to a photosensor (52) of a defocused sensor head (20). The remote pickup head (12) has a reimaging lens (84) and means for selectively adjusting the focus of the lens (84) relative to the target (14) after the pickup head has been fixedly mounted. The aperture setting is kept fixed during the focus adjustment to eliminate the need to recalibrate after the focus adjustment. The defocused sensor head (20) has a defocused relay lens (50) which is selectively out of focus to convey a slightly blurred, out of focus image of the output end of the fiber optic cable (18) to the photosensor (52) to reduce noise, average the light signal and reduce calibration difficulties due to high intensity spots in the image field and to make the unit less susceptible to misfocusing. Precision is further enhanced by provision of a field stop member (86) with a narrow slot, for instance, for passing light only to selected parts of the input end of the fiber optic cable (18) which makes up the optical field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.