Electro-optical board assembly for measuring the temperature of an object surface from infra-red emissions thereof, including an automatic gain control therefore
US5717608A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 1994 |
| Grant date | Feb 10, 1998 |
| Priority date | — |
| Expiry date | Sep 26, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J5/0893
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An automatic gain control technique integrates samples of an incoming analog signal a controlled amount of time so that the magnitudes of the samples lie within the desired input window of an analog-to-digital converter or other signal processing device. The values of the samples are then determined from a combination of the output of the signal processing device and their integration time. This is utilized in a system for determining the temperature of a surface of an object, without contacting the surface, by measuring the level of its infra-red radiation emission. A particular application of the system is to measure the temperature of a semiconductor wafer within a processing chamber while forming integrated circuits on it. The measuring system is configured on a single printed circuit board with an extra height metal heat sink structure to which a cooling unit is mounted. A photodetector and a circuit chip which performs the signal integrations are mounted within the cooling unit and operated at a uniform temperature. The combination of the variable time integration and cooling techniques greatly increases the signal-to-noise ratio of the measuring system. This allows surface t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.