Alexander L. Andreev

Dynamic parameters of electrically controlled light scattering in helix FLC cells

— The light-scattering structures in monomeric FLCs have been considered and a mechanism for the scattering on transient domains in the helix layers has been proposed. An optical response with a bistable characteristic of light scattering and transmission was realized at a defined electrical pulse regime and boundary conditions in electro-optical FLC cells. The total time of the scattering switching on and switching off is less than 400 μsec at ±36 V. They are quite fast, and FLC cells are quite transparent to be used in a stack of 30–100 light-scattering shutters for a volumetric screen of a 3-D display.

P‐120: Low Voltage FLC for Fast Active Matrix Displays

The process of FLC director reorientation in alternating electric field is considered for the case, when interaction of FLC molecules with the substrates results in portion unwinding of helix structure and domain walls motion. Hysteresis-free electrooptical response as fast as 30÷70 μs was achieved in FLC cells of 1.0 and 1.3 μm thickness at the electric field intensity of 1.0÷2.0 V/μm. This result is very important for the practical use of FLC materials in fast active matrix displays.

11.1: Invited Paper: Ferroelectric Liquid Crystals as a Material for Volumetric Displays

Three types of electrically controlled light scattering distinguished on the physical mechanism were studied in monomeric FLC compositions at different boundary conditions and electrical pulse regimes. The total time of scattering switching on and switching off was less than 150, 250 and 500 us for different scattering types. They are rather fast to be used in a volumetric screen based on a stack of 30–100 light-scattering shutters.

Fast bistable intensive light scattering in helix-free ferroelectric liquid crystals.

A new type of ferroelectric liquid crystal (FLC) is considered, where the reorientation of the director (main optical axes) at the interaction of an electric field with the FLCs spontaneous polarization is due to the movement of spatially localized waves with a stationary profile: solitons arise at the transition due to the Maxwellian mechanism of energy dissipation. Under certain conditions, the appearance of such waves leads to the formation of a structure of transient domains, and as a consequence, to the scattering of light. The Maxwellian mechanism of energy dissipation allows one to reduce the electric field strength at which the maximum efficiency of light scattering is achieved down to 2-3 V/μm and to increase the frequency of light modulation up to 3-5 kHz. Intensive bistable light scattering in an electro-optical cell filled with a specially designed helix-free FLC was studied, and a stable scattering state can be switched on and off for a few tens of microseconds and memorized for a few tens of seconds.

8.3: Stereo Glasses with Fast Low Voltage FLC Shutters

Active stereo glasses are manufactured with FLC based shutters that are capable to modulate the light with frequencies up to 1.0 kHz at ±1.5 V and up to 2.0 kHz at ±3.0 V. Used novel FLC materials and cells of 1.5 μm layer thickness provide 30–100 μs response time under 1.0–2.0 V/μm electric field.

P‐232: Ferroelectric Liquid Crystal Cell for Speckle‐Noise Suppression

A new principle and simple technique of suppressing the speckle-noise in images displayed by the laser projection system is proposed. Wave phasing in a laser beam and speckles are destroyed in real time when this beam passes through a single FLC cell where spatially inhomogeneous phase light modulation takes place due to special FLC material and electrical pulse regime.

Electro-optical parameters of FLC layers stabilized by a typical polymer net

A typical polymer net with microcells of different sizes (from 25 x 25 to 200 x 200 μm) was formed by using a lithographic process, both on glass and flexible polymeric substrates. To investigate the influence of polymeric walls on FLC-display cell operation, the typical electro-optical parameters of FLC layers - light transmission and scattering, optical contrast ratio and response time -were measured under different conditions, such as display cell preparation and processing, driving voltage, microcell dimensions, and temperature.

An Effective Method of Suppressing the Speckle-noise Using a Cell with the Helix-free Ferroelectric LC

We suggest a simple and effective method of suppressing the speckle-noise in the lasergenerated images using the high-speed electro-optical cell with the ferroelectric liquid crystal (FLC), in which the helix is absent (compensated). The nature of deformations of FLC smectic layers in the electric field is indicated, and the mechanism of spatially inhomogeneous phase modulation of the laser beam passing through a cell is considered. The results of destruction of the phase relationships in a laser beam and speckle-noise suppressing are presented in comparison with earlier results, when helix FLC was used.

71.3: Invited Paper: Speckle Suppression by Means of Ferroelectric LC Cell

Simultaneous action of low- and high-frequency electric fields on ferroelectric LC cell causes random variations of the refractive index in FLC layer that results in inhomogeneous space and time phase modulation of a laser beam and suppression of speckle- noise in displayed images in real time.

Experimental model of 3D volumetric display based on a stack of FLC light-scattering shutters

3D display with a volumetric screen is developed because it composes the most realistic 3D image of 3D object or scene. The display experimental model using a stack of light-scattering shutters based on the ferroelectric LC layer was created for the first time. Physical mechanisms of FLC layer scattering were studied. The bistable scattering regime which is most appropriate for practical applications was found, and the total time of scattering switching on and switching off was less than 250μs at ± 80 V. The experiments showed that the possible number of FLC shutters in a volumetric screen of the real time 3D display can be as high as 30-100.