In the optical system of the limited reflective sensor, only the regular reflection of a certain limited distance is received because the emitter axis intersects with a receiver axis in the same inclination θ.

Only the regular reflection of a certain limited distance is received with such an optical system.





Moreover, the distance that reaches the peak of the excess gain never changes by the difference of the color because it uses the regular reflection.

(However, the width of detection shortens by the amount of light reflection decrease.)