# A Study of High-Efficiency Laser Headlight Design Using Gradient-Index Lens and Liquid Lens
## 3 Simulation and Analysis of the Headlight Optical System
Liquid optics does not intend to join the full optimization described in Figure 8 only because it is a switch for high beam/low beam. Why not join full optimization in order to achieve best performance for high beam/low beam? It is only because liquid optics is intended to be with aspherical surface which is subject to gravity. We are not able to find the right coefficient to have it optimized. Figure 8: (a,b) Simulation results of the high-beam pattern and experimental results. X and Y axis is the meter. Colors indicate the light intensity via Lux. This center of lighting delivers most powerful lux. Relatively high value of illuminance might be eliminated by control of laser output power. Figure 9: (a,b) Simulation results of low-beam pattern and experimental results. The low-beam lights turned on nine laser sources (2, 3, 4, 5, 6, 7, 8, e, f), with a total power of 4.5 W. Zones I, III and IV had an average illuminance of 20, 0.7 and 17.7 lux, respectively. The light distribution of the low beam is shown in Figure 9a, and detailed experimental data are shown in Figure 9b. The detection point values comply with the specifications, and the cut-off line is also within the specified range. Figure 11a shows the illumination simulation results, which indicates that the cut-off line is within the specified range. Figure 11b shows a bird's eye view of the low beam. To prevent glare, the illumination of Zone III was limited to 0.7 lux, and the height of the cut-off line could not exceed the regulations. The above two conditions of this experiment are within prescribed values, which can effectively prevent glare and the headlight system used modular control. In addition to reducing the laser source power, the cut-off line height could be adjusted to more effectively prevent glare. Figure 11: **(a)** Illumination simulation results from LightTools, **(b)** simulation results of bird’s eye view pattern from LightTools. Figure 10: Optimization process via LightTools based on Monte Carlo merit function. During the optimization process, as soon as the proposed optical design was set up ready in LightTools, the simple ray tracking method will start first, then following LightTool's multiple ray-tracking optimization. If the result is not good, cease then repeat the setting work; restart again for next set up and optimization. Simulation result will be determined after optimization. The experimental simulation proves that, for the high-beam mode, the laser beam passing through the liquid lens was the output of the freeform lens, which fine-tuned the light beam. Consequently, the final high-beam patterns were obtained on the detection surface, as shown in Figure 9a, indicating that the high-beam pattern satisfied the regulatory requirements. Figure 9b shows the corresponding experimental values. The value of each detection point is greater than the regulatory value, suggesting that the optical system of the high-beam mode was in line with expectations. The experimental simulation of the low-beam mode is displayed in Figure 10, suggesting that the output light pattern also satisfied regulatory requirements. The experimental values, shown in Figure 10, were also superior to the regulatory standards, thereby experimentally verifying that the optical system devised in this study is feasible, as shown in Figure 11.