Displacement meter and article manufacturing method

A displacement meter comprising:

• a light source;
• an illumination optical system configured to form a light intensity distribution at a predetermined position on an optical axis by using light from the light source such that a light intensity at a peripheral portion of the light intensity distribution is stronger than a light intensity at a center portion of the light intensity distribution;
• a light deflection portion which has a reflection part on an optical axis and configured to guide light of the light intensity distribution formed by the illumination optical system to a measurement object through an opening in the periphery of the reflection part;
• a first lens unit configured to collect light passing through the opening and illuminate the measurement object;
• a sensor array configured to detect light reflected by the measurement object and reflected by the reflection part of the light deflection portion through the first lens unit;
• and
• a measurement unit configured to detect displacement of the measurement object by using outputs of the sensor array at different timings.

An article manufacturing method comprising:

• measuring displacement of an object by using a displacement meter;
• and
• processing an object based on the measured displacement,
• wherein the displacement meter includes:
• a light source,
• an illumination optical system configured to form a light intensity distribution at a predetermined position on an optical axis by using light from the light source such that a light intensity at a peripheral portion of the light intensity distribution is stronger than a light intensity at a center portion of the light intensity distribution,
• a light deflection portion which has an opening on the optical axis and a reflection part configured to reflect light of the light intensity distribution formed by the illumination optical system at the predetermined position,
• a first lens unit configured to collect light reflected by the reflection part and illuminate a measurement object,
• a sensor array configured to detect light reflected by the measurement object and passing through the opening of the light deflection portion through the first lens unit, and
• a measurement unit configured to detect a displacement of the measurement object by using outputs of the sensor array at different timings.

An article manufacturing method comprising:

• measuring displacement of an object by using a displacement meter;
• and
• processing an object based on the measured displacement,
• wherein the displacement meter includes:
• a light source,
• an illumination optical system configured to form a light intensity distribution at a predetermined position on an optical axis by using light from the light source such that a light intensity at a peripheral portion of the light intensity distribution is stronger than a light intensity at a center portion of the light intensity distribution,
• a light deflection portion which has a reflection part on an optical axis and configured to guide light of the light intensity distribution formed by the illumination optical system to a measurement object through an opening in the periphery of the reflection part,
• a first lens unit configured to collect light passing through the opening and illuminates the measurement object,
• a sensor array configured to detect light reflected by the measurement object and reflected by the reflection part of the light deflection portion through the first lens unit, and
• a measurement unit configured to detect a displacement of the measurement object by using outputs of the sensor array at different timings.