| 摘要 |
PURPOSE:To decrease emission spots on the surface of a front lens by mounting an inner lens group consisting of a first lens synthetically functioning as a concave lens and a second lens, which has the same axis and collectively takes a convex shape by Fresnel cut, etc., in succession from the side of a light- emitting diode. CONSTITUTION:A light-emitting diode 1 is fitted to a printed substrate 2, and a front lens 3 is set up on the front side of the diode 1. An inner lens group 4 composed of a first lens 4a, which has the same axis as an optical axis for the light-emitting diode and is cut in a concave lens manner, and a second lens 4b, which has an optical axis approximately coinciding with the optical axis for the first lens 4a and is formed to a convex lens by using a cut means such as one for a Fresnel lens, is mounted between the light-emitting diode 1 and the front lens 3. The first lens widens the angle of radiation of narrow beams from the light-emitting diode, and the second lens changes the beams having the widened angle of radiation into parallel beams. Accordingly, beams are projected uniformly to the front lens, thus removing emission spots on said front lens surface. |
