Design Of The Lens Type Light Screen Target And Research On Detection Sensitivity With A 90°Field Of View

The detection sensitivity which stands for detection ability of the speeding target is an important index.When the velocity measurement target is designed, the detection sensitivity is a primary factor to consider. The detection sensitivity is directly related to the light energy which distributes in the target surface. Therefore, researching distribution of light energy is important. This thesis designs the Lens Type Light Screen Target. This kind of target meets the demand of large detection area. The concrete contents of research are as follows:Firstly,detection sensitivity is analyzed theoretically.L-shaped rectangular light screen is evolved by the arc light screen. The factors that affect detection sensitivity of L-shaped rectangular light screen are obtained by analyzing detection sensitivity of arc light screen.Secondly, the distribution of light energy is simulated. The simulation analysis is divided into two parts:1)On the one hand, under the ideal condition, the mathematical models of illuminance values are built respectively. Due to different sizes of L-shaped rectangular detecting light screen and numbers of detecting lens, those models are different.With the help of MATLAB software, illuminance values are simulated. According to the simulation results, a conclusion is drawn. When the size of L-shaped rectangular detecting light screen is the same, the number of detecting lens is numerous, and distribution of illuminance values are even.However, the number of detecting lens is the same, L-shaped rectangular detecting light screen is big, and distribution of illuminance values are uneven.2)On the other hand, the diameter of projectile is considered. The mathematical model of illuminance values of target surface is established. The illuminance values are simulated by the MATLAB software. The simulation diagram shows that detection sensitivity is related to the distance where the projectile is from away light source. The distance is short, and detection sensitivity is high. And detection sensitivity of the edge of the field is mainly affected by the View Angle.Finally, according to the simulation results, the Lens Type Light Screen Target is designed. In order to ensure that there is no deviation between the detection device and the light source, the mechanical structure can move 15 mm in the horizontal direction and adjust slightly ± 1.5mm in the vertical direction.By doing the experiments and analyzing the experimental results, detection sensitivity of the Lens Type Light Screen Target is consistent with the theoretical analysis and simulation analysis.So the Lens Type Light Screen Target can be used for the actual measurement.