Phase difference control device
US11402320B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 30, 2019 |
| Grant date | Aug 2, 2022 |
| Priority date | — |
| Expiry date | Apr 11, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/211
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A phase difference control device comprises: a splitting polarizer splitting a light incident from a light source into a measurement light and a reference light, both of which are linearly polarized; a PEM imparting a phase difference to the measurement and reference lights to correspond to the spectrometry; a PEM driver supplying a modulation voltage to the PEM; a PEM control circuit inputting the reference light as a feedback signal and outputting a modulation control quantity signal to the PEM driver; and a CPU circuit monitoring the wavelength of the light in the splitting polarizer to input a wavelength variation as a wavelength signal, wherein the CPU circuit converts the wavelength signal to a feedforward signal which is output to the PEM control circuit; and the PEM control circuit performs arithmetic processing by the feedback and feedforward signals to output the modulation control quantity signal to the PEM driver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.