LCVR Driver
A small low-cost OEM electronic controller board for liquid crystal devices
with user-programmable magnitude and frequency.
A Liquid Crystal Variable Retarder (LCVR, also called a phase retarder or rotator) is a liquid crystal filled waveplate device placed in the light path of an optical system to allow its electronic modulation, by phase retardation or rotation of the plane of polarization. LCVRs are filled with a solution of nematic liquid crystal (LC) molecules which rotate the plane of polarization of transmitted light. Two transparent conductive films1) allow an AC voltage to be applied across the optics cell. As the voltage is increased, the default orientation of the LC molecules is disrupted, changing the degree of rotation or optical phase retardation of transmitted polarized light. Ferroelectric Liquid Crystal Devices (FLC), are similar to LCVRs, but they have the advantage of being able to switch very rapidly in response to an applied DC field.
LCVRs are compact, robust nematic LC devices ideally suited as OEM components of analytical instrumentation. The voltage used to drive them is provided by a liquid crystal controller which applies a precisely generated 50% duty cycle square wave with zero DC component. While several LCVR manufacturers offer benchtop liquid crystal controllers, the LCVR Driver Wildcard is the only commercially available LC electronic controller-driver suitable for embedding in a microcontroller-based OEM instrument.
LCVRs are used for various types of optical analysis including Polarimetry and Ellipsometry. Used in conjunction with polarizers they become useful optical switches. The LCVR Driver Wildcard may be used to drive OEM LCVRs and optical modulators such as those available from Meadowlark or Thor Labs.
Nematic liquid crystal devices are used for:
- Liquid crystal variable filters and liquid crystal tunable filters (LCTFs),
- Liquid crystal variable attenuators,
- Electronically controlled optical shutters,
- Optical modulation and optical attenuation,
- Polarization rotation,
- Variable phase retarders,
- As optical modulators or optical valves, and,
- Liquid crystal variable waveplates.