Tunable Aperture With Liquid Crystal for Real-Time Distance Sensor

For distance detection, a tunable aperture using liquid crystal is proposed, achieving high resolution images in real-time. The tunable aperture inserted into a camera has been designed to two sizes, which can create different Depth of Field images. By analyzing these two images, distance to object can be extracted. Initially, the aperture has large size with zero voltage. When the driving voltage is applied, the aperture transfers itself to smaller size by realignment of liquid crystal molecules in the device. The diameter of aperture is 4.4 mm with f/1.8 and 2.0 mm with f/4.0. The proposed device has low driving voltage of 2.8 V and fast response time of 9.84 ms. Compact size aperture of 10 × 10×1.8 mm
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is assembled in a camera with focal length of 8 mm which contains 5 glass lenses and 1/2.7inch full high definition (FHD) image sensor. The tunable aperture has high stability due to no mechanically moving parts. This distance sensor can be applied to the various field of depth map application which is the self-driving car, drones and manufacturing machine.