This torque limiter is configured from a ring body and a spring-form part provided in the ring body. The charge pump is constituted by first and second cascode current mirrors, as well as first and second switching transistors. This increases efficiency and compatibility with existing design models and reduces cost. The encapsulant has silicon dioxide and exhibits a refractive index of about 1. The fluorescing lens andor any intermediate focusing lenses are made from any desired material that may be impregnated or coated with one or more fluorescing compounds andor one or more light-absorbing dyes or pigments.