Sensitivity determining method for maintenance of an optical sensor system and sensitivity determining filter therefor

Abstract

The present invention provides sensitivity determining method for maintenance of an optical sensor system and sensitivity determining filter used therefor. An attenuation filter is disposed in a projected light area between a light projection unit and a light receiving unit of an optical sensor system, and in the case where the light receiving unit receiving a quantity reduced light transmitted through the attenuation filter outputs a signal indicative of light reception, a decision is made such that sensitivity of the optical sensor system is sufficiently high. On the other hand, in the case where the light receiving unit outputs signal indicative of insufficient light reception, a decision is made such that sensitivity of the optical sensor system is poor. In the case where sensitivity of the optical sensor system is poor, it is possible to readily find the cause of the sensitivity being poor, by wiping a light projection surface, a light receiving surface, a reflection surface in succession, or by investigating an offset of the optical axis.

Dependencies are inferred from the claim text.