Liquid-crystal varactors with fast switching times for microwave applications

2008 ◽  
Vol 44 (7) ◽  
pp. 480 ◽  
Author(s):  
F. Goelden ◽  
A. Gaebler ◽  
S. Mueller ◽  
A. Lapanik ◽  
W. Haase ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Fast Switching ◽  
Switching Times ◽  
Microwave Applications

Ferroelektrische Flüssigkristall - Mischungen mit Kohlenhydrat - Derivaten als Dotierstoffe / Ferroelectric Liquid Crystal Mixtures with Carbohydrate Derivates as Dopants

1989 ◽  
Vol 44 (7) ◽  
pp. 675-679 ◽  
Author(s):  
V. Vill ◽  
F. Fischer ◽  
J. Thiem
Keyword(s):  
Liquid Crystal ◽  
Chiral Center ◽  
Ferroelectric Liquid Crystal ◽  
Fast Switching ◽  
Switching Times ◽  
Smectic Phases ◽  
First Time ◽  
Helical Twisting Power

Abstract For the first time carbohydrate derivatives were studied as dopants for calamitic smectic phases. Fast switching ferroelectric cells could be realized, and electroclinic effects were observed. By inversion of configuration at a chiral center of these compounds switching times, solubility, and helical twisting power vary by orders of magnitude. The studied derivatives showed modest solubility properties.

scholarly journals Holographic Polymer-Dispersed Liquid Crystals: Materials, Formation, and Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-52 ◽  
Author(s):  
Y. J. Liu ◽  
X. W. Sun
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Refractive Index Profile ◽  
Single Step ◽  
Fast Switching ◽  
Polymer Dispersed Liquid Crystal ◽  
Current State ◽  
Index Matching ◽  
Polymer Dispersed ◽  
Materials Used

By combining polymer-dispersed liquid crystal (PDLC) and holography, holographic PDLC (H-PDLC) has emerged as a new composite material for switchable or tunable optical devices. Generally, H-PDLC structures are created in a liquid crystal cell filled with polymer-dispersed liquid crystal materials by recording the interference pattern generated by two or more coherent laser beams which is a fast and single-step fabrication. With a relatively ideal phase separation between liquid crystals and polymers, periodic refractive index profile is formed in the cell and thus light can be diffracted. Under a suitable electric field, the light diffraction behavior disappears due to the index matching between liquid crystals and polymers. H-PDLCs show a fast switching time due to the small size of the liquid crystal droplets. So far, H-PDLCs have been applied in many promising applications in photonics, such as flat panel displays, switchable gratings, switchable lasers, switchable microlenses, and switchable photonic crystals. In this paper, we review the current state-of-the-art of H-PDLCs including the materials used to date, the grating formation dynamics and simulations, the optimization of electro-optical properties, the photonic applications, and the issues existed in H-PDLCs.

Design Method for Fast Switching Seat Valves for Digital Displacement® Machines

2014 ◽  
Author(s):  
Daniel B. Roemer ◽  
Per Johansen ◽  
Henrik C. Pedersen ◽  
Torben O. Andersen
Keyword(s):  
Pressure Loss ◽  
Design Method ◽  
Thermal Dissipation ◽  
Valve Design ◽  
Stroke Length ◽  
Efficient Operation ◽  
Fast Switching ◽  
Switching Times ◽  
High Bandwidth ◽  
Electro Magnetic

Digital Displacement® (DD) machines are upcoming technology where the displacement of each pressure chamber is controlled electronically by use of two fast switching seat valves. The effective displacement and operation type (pumping/motoring) may be controlled by manipulating the seat valves corresponding to the piston movement, which has been shown to facilitate superior part load efficiency combined with high bandwidth compared to traditional displacement machines. However, DD machines need fast switching on-off valves with low pressure loss for efficient operation, especially in fast rotating operation, where switching times must be performed within a few milliseconds. These valve requirements make a simulation based design approach essential, where mechanical strength, thermal dissipation, fluid dynamics and electro-magnetic dynamics must be taken into account. In this paper a complete design method for DD seat valves are presented, taking into account the significant aspects related to obtaining efficient DD valves with basis in a given DD machine specifications. The seat area is minimized and the stroke length is minimized to obtain fast switching times while considering the pressure loss of the valves. A coupled optimization is finally conducted to optimize the electro-magnetic actuator, leading to a valve design based on the chosen valve topology. The design method is applied to an example DD machine and the resulting valve design fulfilling the requirements is presented.

Chiral-induced self-assembly sphere phase liquid crystal with fast switching time

2014 ◽  
Vol 104 (9) ◽  
pp. 091116 ◽  
Author(s):  
Ji-Liang Zhu ◽  
Shui-Bin Ni ◽  
Chao Ping Chen ◽  
Dong-Qing Wu ◽  
Xiao-Long Song ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Self Assembly ◽  
Switching Time ◽  
Fast Switching ◽  
Phase Liquid

40‐1: Invited Paper: Fast‐Switching Liquid Crystal Devices for Near‐Eye and Head‐Up Displays

2020 ◽  
Vol 51 (1) ◽  
pp. 567-570
Author(s):  
Tao Zhan ◽  
Jianghao Xiong ◽  
Guanjun Tan ◽  
Shin-Tson Wu
Keyword(s):  
Liquid Crystal ◽  
Fast Switching ◽  
Liquid Crystal Devices
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