Image recognition controlled USB multichannel liquid crystal driver

Many liquid crystal devices require a number of different voltage signals in order to drive them appropriately. Tunable focus lenses with multiple electrodes [1], beam steering devices or stacked switchable polarization gratings [2] are examples in which multiple driver signals are required. Commercially available Data Acquisition Devices (DAQs) can offer a number of digital and analog in/outputs. For these DAQs either the number of analog outputs is limited, the possible frequencies of the different channels are limited or the cost is very high. For this reason, we have developed a small USB-controlled electronic device which is able to generate 16 analog voltage signals up to -10V/+10V output at a maximum frequency of 6 kHz for each channel. A graphical user interface has been written in Python to set each output channel to the desired voltage signal. In order to demonstrate the possibilities of the electronic driver, a program was written to track an object’s motion using the webcam on a laptop. Depending on the movement of the object, voltage signals are generated to drive a liquid crystal beam steering device. The direction of a laser beam is steered towards different directions based on the object’s movement. In future work, the aim is to implement a head tracking algorithm in order to implement a goggle-free 3D display with LC beam steering. In this way the best 3D experience can be provided irrespective of the position of the observer with respect to the display. [1] O. Willekens, et al., Ferroelectric thin films with liquid crystal for gradient index applications, Optics Express 24, 8088 (2016) [2] M.J. Escuti, et al., Beam steering devices including stacked liquid crystal polarization gratings and related methods of operation, US patent 8982313 B2