| 摘要 |
PROBLEM TO BE SOLVED: To prevent lowering of damping ratio of infra-red ray reaching a human body sensor. SOLUTION: The lighting fixture has a main body 2 holding a lamp 1 in an appropriate means covered with a globe 3, a material of which is made to enable to transmit (for instance, made to be of polyethylene resin) infra-red ray (about 9 to 10 μm) emitted from a human body, and at the same time, a human body sensor 4 is set in an inner face side of the globe 3, and further, a part 5 opposite to the human body sensor 4 in the globe 3 is made to be a curved surface (a part of a roughly spherical surface) at nearly the same distance from the sensor 4. In other words, at a part shown in shaded area, each distance from detecting elements within the human body sensor 4 to the above part of the globe 3 almost satisfies the following formula. r1=r2=r3 What is called a pyroelectric infra-red ray sensor is suitable as a human body sensor. Or, more preferably, the human body sensor 4 is to be arranged in opposition to nearly a center of the globe 3, and the vicinity of the center of the globe 3, that is, the above part 5 is to be a curved surface almost at the same distance from the human body sensor 4. Further, with the globe 3, parts other than the above part 5 are to be of a gently curved surface except for the vicinity of a top end. |
