Inclination detecting apparatus having an intensity adjusting unit

An inclination detecting device comprising:

• a light emitting system for emitting a parallel light flux to a predetermined detection area on a substrate;
• a light receiving system for condensing the light reflected from said substrate, detecting the reflected light photoelectrically and outputting a photoelectric signal in accordance with the intensity of the reflected light;
• an adjusting unit for changing the intensity of said photoelectric signal in accordance with a change in reflective characteristics of the light flux in said detection area;
• and
• a unit for detecting an inclination of said substrate with respect to a predetermined reference plane based on said photoelectric signal from said light receiving system.

An inclination detecting method comprising:

• the first step of emitting a parallel light flux to a substrate and obtaining, by condensing the light reflected from said substrate and detecting the reflected light photoelectrically, a photoelectric signal in accordance with the intensity of the reflected light;
• the second step of changing the intensity of said photoelectric signal in accordance with at least one of the shape and the size of an illumination area of said parallel light flux on said substrate or variation in reflective characteristics on said substrate;
• and
• the third step of detecting an inclination of said substrate with respect to a predetermined reference plane based on said photoelectric signal changed in the second step.