| Summary: | 碩士 === 國立交通大學 === 光電科技學程 === 103 === The modeling of automobile light has become a special design language for describing an automobile brand in the car industry. With an index significance, it is used to show a different charm. Under the leadership of international companies, a light guiding bar is widely applied to the design of car lights. However, common design methods cannot be applied to the design of car tail lights of more than 60 cm in size with a transparent sense and without highlights that visually meet the ECE Regulation No. 7.Therefore, this paper attempts to determine the best optimal design parameter combination that will address the issues mentioned.
This paper discusses the ECE Regulation No. 7, the composition of lights, specifications of a car and the principle behind the design, and the design and composition of car tail lights. LED arrangement spacing, inner surface treatment, reflecting mirror at the base, and other multiple parameters are used to attain no visual highlights. If the LED spacing is 12 mm, the test is conducted for black base accompanied by a transparent plain inner case, inner blasting, inner with white paint, and inner with diffused film. Test results shows that the evenness degree of the inner with diffused film is best at 77.5%. If LED spacing is shortened from 12 mm to 9 mm, the evenness degree of the inner with diffused film is increased by 6.71%, or 84.21% in total. After being accompanied by a reflecting mirror at the base, the average illumination of car tail lights increased by 35.6%, from 140.66 Lux to 190.77 Lux as a result of the reflecting effect of the sidewalls at the base. However, the evenness degree decreased by 11.91% from 84.21% to 72.3%.
This paper shows the optimal conditions that satisfy customer requirements are as follows: no obvious visual highlights 120˚LED, LED spacing of 9mm, inner with diffused film, and a black base. A goniophotometer is used to conduct photometric verification. Photometric results show that the brightness of partial test spots in inner with diffused plate is 17cd, which is higher than the upper limit for tail lights in the ECE Regulation No. 7. Therefore, the inner with white paint with an evenness degree lower than the inner with diffused film is used to conduct the photometric test. The results show that the photometric results of fixed side lights and fixed side lights with movable side lights can meet the photometric requirements of ECE Regulation No. 7 with regard to tail lights.
From the above results, the conditions meeting the customer’s requirements such as no obvious visual highlights, the provisions in the ECE Regulation No. 7 regarding the tail lights include 120˚LED, LED spacing of 9 mm, inner with diffused film, and black base. Car tail lights with these conditions can be approved by the automotive research &; testing center, and receive a certificate from vehicle safety certification center.
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