LIGHT CONTROL ELEMENT AND ILLUMINATING DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a light control element which realizes a well designed light guide type pole illuminating device in which loss of light from a light source caused by illuminating upwards or returning to the light source is reduced. SOLUTION: The light control element which controls light distribution to prescribed direction is disposed in front of a light emitting portion of a light source. The light control element has a reflective prism 4 consisting of a plurality of element prisms 3 each of which has a cross-section of a right angle isosceles triangular shape and each base of which faces the light emitting portion 2 of the light source. The element prisms 3 are disposed in a radial manner around a summit 6 of a right circular cone setting their bases along on the side of the right circular cone. Thereby the reflective prism 4 reflexes the light from the light source to the prescribed light distribution direction. A refracting prism 12 is disposed between the light emitting portion 2 of the light source and the reflective prism 4 in order to refract and guide the light which deviates from a prescribed beam angle into the reflective prism 4. By these constitution, the light leak upwards or the light loss caused by the direct returning of the reflected light to the power source is reduced, and illumination efficiency is improved. The design of the illuminating device is also improved because its transparency is raised. COPYRIGHT: (C)2004,JPO