The goal of the present work is to create a miniature 2D light scanning device without any moving parts using integrated electro-optic (EO) liquid crystal (LC) material. The design is based on changing the propagation direction of a light beam when it is incident to an electro-optic medium with a voltage-controlled index of refraction. To achieve 2D beam steering and scanning, the device is designed in two stages. For horizontal beam steering, a LC prism (thickness = 10 μm) created between two glasses is used to deflect beam by refraction due to change in refractive index of LC. For vertical beam steering, a virtual prism is created between two glasses by offsetting top and bottom electrodes. When an electric field is applied to the electrodes, LC directors create a virtual prism due to physical offset between top and bottom electrodes help to achieve beam deflection in vertical direction. In this work, a simulation study is conducted on the proposed design to achieve 2D deflection of laser beam (λ=632 nm). According to Snell’s law, theoretically, a maximum horizontal deflection of 10.52° is achieved at a prism angle, and incident angle of 66.1° and 21.99° respectively. Whereas through a simulation study, maximum horizontal deflection of 34° and maximum vertical deflection of 13° is achieved at given incident angle. This low-cost and lightweight optical scanner can fit inside a tube with a diameter of less than 5 mm and can be implemented for augmented reality (AR), virtual reality (VR), or standalone microdisplay applications.
Many of the electroactive polymers are dielectric and often demand high operating voltages for actuation (<<10 MV/m). These EAP-based actuators require metallic electrode layers on the surface to apply the voltage. Due to high operating voltage, heat is produced at the surface of electrodes due to resistive heating and dielectric losses in polymer material. In the case of actuators based on active and passive layer configurations with metallic electrodes, this heat could affect the performance, as the generated heat is transferred between the layers. In the present work, a PVDF terpolymer and Kapton tape-based bilayer actuator is developed, and simulation and experimental study are carried out to check the effect of DC high voltages on heat production within layers. The contribution of this heat to the bending of the actuator is also analyzed. It is found that significant heat is generated that can affect deflection process of the EAP actuator. The total electromechanical bending deflection produced at the E-field of 20 MV/m is ~80 degrees whereas deflection due heat generated at this voltage is ~15 degrees. Hence, the total deflection produced can be claimed as a combination of thermal and electro-mechanical effects.
Light beam deflectors and scanners have great potential in displays and microscopy for industrial and medical applications. A liquid crystal (LC) material that responds to external stimuli is a promising candidate for such applications. The goal of the proposed work is to create a miniature light scanning device without any moving parts using integrated electro-optic(EO) LC material. The design is based on changing the propagation direction of a light beam when it is incident to an electro-optic medium with a voltage-controlled index of refraction. The current design consists of two horizontal LC cell cascaded prisms (active Prism I and II) for horizontal beam deflection and a vertical prism (passive) at the end of the horizontal stage for vertical beam deflection. In the present work, a mathematical model and simulation study is conducted on the proposed design to achieve 2D deflection of the beam (λ=632 nm). The optimized prism or apex angle of active prisms I and II are 63 and 56.7 respectively, whereas the prism angle of the passive prism is 37.5. With an incident beam angle (θ1) of 9 at the entry of prism I, maximum horizontal deflection of >36 and maximum vertical deflection of >13 is achieved through theoretical and simulation study.
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