| 摘要 |
PURPOSE:To prevent the titled sensor from being affected by environmental temp. by attaching a light receiving element for temp. compensation for which part of the light radiated from a light emitting element is used as a light source into the case of the light emitting element and controlling the power feed quantity to the light emitting element in such a manner that the specified output of the light receiving element for temp. compensation is maintained. CONSTITUTION:The light receiving element 4 for temp. compensation is attached at the point in the case of the light emitting element where the light receiving element can receive the irradiation of the light emitted the body of the element 2, i.e., a photodi ode chip 2. A circuit for controlling the power feed quantity to the light emitting element is provided to invariably maintain the output of the light receiving element 4 by suppressing the floating of the output of the light receiving element when the output of said element is going to float according to the fluctuation of the environmen tal temp. The deterioration in the accuracy of the measurement with the sensor A arising from the influence of the ambient environmental temp. on the electrical characteristics of the light emitting element 2, the light receiving element 3 and the light receiving element 4 for temp. compensation is thereby averted. The elements 2-4 having the approximate temp. characteristics as far as possible are used.
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