Electro-Optical Devices from Banana-Shaped Liquid Crystals
Abstract: This invention offers a display that can be switched between scattering and clear states c. 100 times faster than PDLCs with principally 180 degree viewing angle. In addition, the switching modes – from opaque to clear and clear to opaque - can be interchanged in less than a second. After changeover, both the opaque and clear states can be stable at zero fields. The work of the device in reflection mode was also demonstrated. This invention encompasses a liquid crystal device comprising tilted smectic phases of banana-shaped (bent-core) liquid crystal molecules and a method for fabricating a light modulating device. The method comprises the steps of providing a pair of substrates with a cell gap between and permanently disposing at least one banana-shaped liquid crystal material into the cell gap. The present invention also provides a method of generating an image by providing a pair of substrates with a cell gap, providing transparent electrodes on each of the substrates adjacent to the cell gap, disposing at least one banana-shaped liquid crystal material into the cell gap, and applying an electric field across the electrodes. The tilted smectic phases of banana-shaped liquid crystal may be in either a racemic or a chiral state. The application of an electric field transitions the banana-shaped liquid crystal material between the racemic and chiral states, and both the racemic and the chiral states are stable in the absence of an electric field.
Useful wherever PDLCs speed and viewing angle is not enough, for versatile optical devices both in transmission or reflection mode, where both video-rate applications and optical storage capabilities are required. Examples include cell phones, personal computers, electronic books, and in light shutters that use energy only during switchover between modes.
Versatility, faster switching speed, greater viewing angle, and no backlighting required.
Inventors: Drs. Antal Jakli, Dr. Liang-Chy Chien, D. Kruerke, S. Sawade, & G. Heppke
Associate Director, Technology Commercialization
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