| 摘要 |
PROBLEM TO BE SOLVED: To solve problems of increase of power consumption and costs since many LED lamps are required because the light of the LED lamp is poorly collected since a single focus inner lens is adopted to the conventional type LED traffic signal lighting tool. SOLUTION: The problems are solved by constituting the LED traffic signal lighting tool so that homogeneous brightness is obtained on an outer lens surface and further light distribution characteristics to satisfy regulations is obtained by a smaller number of LED lamps in the front direction by constituting the LED traffic signal lighting tool 1 in which the focal distance f3 of the inner lens 3 in the outer circumference is made equal to the distance between the outer circumference and a point where the extension of a line connecting the outer circumference of the lens and the LED lamp provided on the outer end of a light source board crosses the center line Z and the focal distance 1 is made equal to the distance to the LED lamp 5 at the center of an outer lens and the focal distance changes between both focal distances at the intermediate position. |
