Position detecting system

A detecting system operating under cyclic fluorescent light, comprising:

• a light emitter which emits light during even multiple cycles of the fluorescent light;
• and
• a light receiver which receives light from said light emitter during a half cycle of a light emitting cycle, wherein
• the effect of the fluorescent light is removed by operation of said light emitter and said light receiver.

A detecting system operating under fluorescent light, comprising:

• a light emitter providing emission during one cycle of the fluorescent light, stopping emission, and maintaining a non-emitting condition during at least one following cycle of the fluorescent light;
• and
• a light receiver receiving light from said light emitter in a cycle which is related to the fluorescent light cycle such at the fluorescent light cycle is an integer multiple of the light receiving cycle;
• wherein the effect of the fluorescent light is removed by operation of said light emitter and said light receiver.

A position detecting system for detecting a relative position between a first object and a second object under cyclic fluorescent light, comprising:

• a light emitter provided on the first object to emit light in a cyclic manner, the light emitter emitting light for a predetermined period during each light emitting cycle of the light emitter, wherein the light emitting cycle is a multiple of a cycle of the fluorescent light;
• a light receiver provided on the second object, the light receiver receiving light from the light emitter in a light receiving cycle which is related to the light emitting cycle in a manner such that the light emitting cycle is an integer multiple of the light receiving cycle;
• and
• a calculator calculating the relative position of the first and second objects based on an output of the light receiver, wherein the effect of the fluorescent light is removed by operation of the light emitter and the light receiver.