NEMATIC LIQUID CRYSTAL DEVICES
LIQUID CRYSTAL MODES
Modes correlate to the behavior mechanisms of liquid crystal devices. BVO manufactures nematic phase liquid crystal devices and each mode has its advantages.
Electronically Controlled Birefringence (ECB) Mode: Versatile tunable retarder. Analog control of LC molecule phase allows specific wavelength control. Products: variable retarders and modulators.
Optically Compensated Bend (Pi-cell) Mode: High speed modulator. Differs from ECB mode by having parallel aligned molecules reducing rotational torque, which increases switching speed. Products: fast optical shutters, rapid Lyot tunable filters.
Twisted Nematic (TN) Mode: Most achromatic variable attenuator. LC molecules have 90 degree twist due to orthogonal rubbed alignment layers resulting in polarization rotation to incoming polarized light. The rotation of LC is unwound as voltage is increased. Products: achromatic variable broadband attenuators.
Vertically Aligned (VA) Mode: Highest contrast ratio. LC molecules are vertically aligned with zero voltage with no residual birefringence due to pre-tilt. The result is an exceptional dark state. Products: high contrast variable attenuators.