ファントムボードを用いたLED交通信号灯器の開発

抄録

Blue LEDs are now mass-produced, and road traffic signal heads using LED systems are being used. LED signal heads have advantages such as energy savings and a long life. However, newly proposed LED signal heads have difficulty reducing problems such as the washout phenomenon. In this paper, we have proposed reducing the washout phenomenon of LED signal heads by using LED element 192 and the low-reflection black plate called a“phantom board”on a blank area between the elements. On the basis of light intensity distribution and luminance uniformity measurements, it was confirmed that the LED signal head we proposed satisfies the conditions described in the traffic signal lighting specifications of the National Police Agency. The visibility of the signal head was improved, as apparent from the before and after improvement pictures taken in the morning and the evening when the sun was at a low altitude and as a result of the phantom ratio.