Abstract: An optical device is disclosed herein. In some embodiments, a optical device includes a liquid crystal element having a top surface, a bottom surface, and sides separating the top surface and the bottom surface, and an outer layer surrounding the sides of the liquid crystal element, wherein the liquid crystal element comprises a first base layer, a second base layer, a liquid crystal layer positioned between the first base layer and the second base layer, a pressure-sensitive adhesive layer positioned between the first base layer and the liquid crystal layer, and a spacer to maintain a gap between the first base layer and the second base layer, wherein the optical device satisfies Equation 1: ?T2×0.4?T1?T2?T2×0.4??[Equation 1] wherein, T1 is a thickness of the outer layer, and T2 is a thickness of the liquid crystal element.

Abstract: The present invention relates to a system for measuring dynamic information of a golf ball for a screen golf, and more particularly to, such a system for measuring dynamic information of a golf ball, which accurately measures the angle and speed of a golf ball and a golf club from four different optical beam planes positioned in front of a golf ball hitting platform in a screen golf facility installed mainly in an indoor driving range so as to implement an expected carry distance and falling point of the golf ball in the form of a three-dimensional image based on the measurements of the angle and speed of the golf ball.