Spectrometer with direct drive high speed oscillating grating
US4969739A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 9, 1989 |
| Grant date | Nov 13, 1990 |
| Priority date | — |
| Expiry date | Jan 9, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2003/1273
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical grating is oscillated at a high rate to scan a narrow wavelength band of light through the spectrum dispersed by the grating. The grating is connected integrally with the rotor of a motor, which is energized to oscillate its rotor between selected limits. The direction of rotation of the motor is controlled by an H drive circuit connected to a coil of the motor. The speed of the motor is controlled by a pulse train applied to the motor coil through the H drive. The pulse train has a duty cycle varying inversely with the motor speed. The duty cycle of the pulse train is controlled by a counter which is connected to count high frequency pulses and which is reset each time the grating rotates through an angular increment. The limits of the oscillation of the grating and the rate of rotation of the grating between the limits are selectively variable. Output readings from the spectrophotometer are taken at equal angular increments of the grating and these readings are converted to values occurring at equal wavelength increments by a computer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.