Patent ID: 8193726

Claim:
A fluorescent light temperature sensor, comprising: a fluorescent material; a light projecting element projecting light onto the fluorescent material; a driving circuit driving the light projecting element; a light receiving element receiving fluorescent light emitted from the fluorescent material and producing an output signal based on the fluorescent light; a signal processing circuit generating a temperature signal, for a temperature measurement environment separate from the light projecting element, from the output signal of the light receiving element; a controlling circuit controlling the driving of the driving circuit through sending a control signal to the driving circuit so as to maintain a uniform intensity for the fluorescent light of the fluorescent material based on the output signal from the light receiving element; and an evaluating device evaluating the service life of the light projecting element in advance based on a control signal from the controlling circuit, wherein the control signal is based on at least one of an actuation frequency of the controlling circuit and a compensating current provided to the light projecting element.