PHASE DIFFERENCE CONTROL DEVICE

• Main Author: MIYOSHI, Yuichi
• Format: Patent
• Language: English; French; German
• Published: 14.08.2024
• Subjects: COLORIMETRY; CONTROLLING; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT,POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED,VISIBLE OR ULTRA-VIOLET LIGHT; MEASURING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; RADIATION PYROMETRY; REGULATING; SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TESTING

The present invention relates to a technique for improving a response characteristic of a phase difference control device that can be used in a circular dichroism (CD) dispersion meter. The phase difference control device is provided with a splitting polarizer 14 which splits light from a light source 12 into linearly polarized measuring light and linearly polarized reference light, a photoelastic modulator (PEM) 16 which imparts a phase difference to the measuring light and the reference light to correspond to spectral measurement, a PEM driver 18 which supplies a modulation voltage to the PEM 16, a PEM control circuit 24 into which the reference light is input as a feedback signal, and which outputs a modulation control quantity signal to the PEM driver 18, and a CPU circuit 26 which monitors the wavelength of light from the splitting polarizer 14 and into which a change in wavelength is input as a wavelength signal, wherein the CPU circuit 26 converts the wavelength signal into a feed-forward signal, and the feed-forward signal is input into the PEM control circuit 24, and the PEM control circuit 24 performs arithmetic processing using the feedback signal and the feed-forward signal, and outputs the modulation control quantity signal to the PEM driver 18.