Spectroradio-meter and spectrophotometer
US4867563A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 1985 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Oct 15, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/127
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To provide sufficient sensitivity, spectral resolution and speed of measurement for field environmental measurements in a portable spectroradiometer, a silicon photodiode receives light: (1) having a bandwidth in the range of between 2 and 15 nm (nanometers) from a pivotable concave holographic diffraction grating within the wavelength range of between 250 and 1150 nm at a scanning rate in the range of 20 to 100 nm per second; (2) having stray light of high intensity and undesired frequencies and the shorter wavelength harmonics of the selected frequency range blocked by filters; and (3) having flux of at least 10 microwatts per square meter of diffuser plate for each nanometer of bandwidth. Automatic electrical zeroing is obtained by blocking all light once at the beginning of each scan, obtaining an electrical drift-related signal and using the drift signal to adjust the measured signal during the scan. Several different sensing interfaces can be used, including a quartz, light fiber probe having at least a 50% packing density and a cone angle of at least 24 degrees. The data and the programming storage is at least 30K bytes but the instrument uses no more than watts of power whe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.