Displacement measurement device, measurement system, and displacement measurement method

A displacement measurement device comprising:

• a light projecting unit configured to generate a light beam having a predetermined wavelength width;
• a sensor head configured to emit the light beam through a member by which wavelength dispersion occurs according to a refractive index so that a focus is formed on a measurement target surface of a measurement target object, and receive a light beam that is reflected at the measurement target surface within the emitted light beam;
• a storage unit configured to store a function using a distance between the sensor head and the measurement target surface as a variable;
• and
• a control unit configured to calculate the distance based on a wavelength of the light beam received by the sensor head,
• wherein the control unit calculates a value of the function by using a first distance between the sensor head and a measurement target surface of a first measurement target object which is the measurement target object as a value of the variable, and corrects the calculated first distance using the calculated value of the function.

A displacement measurement method comprising:

• a step of generating a light beam;
• a step of emitting the light beam to a measurement target object of which a measured value and an actual displacement are nonlinear from a sensor head so that a focus is formed on a measurement target surface of the measurement target object;
• a step of receiving a light beam that is reflected at the measurement target surface within the emitted light beam;
• a step of calculating a distance between the sensor head and the measurement target surface based on a wavelength of the received light beam;
• a step of calculating a value of a function by serving the calculated distance as a value of a variable in the function using the distance as the variable;
• and
• a step of correcting the calculated distance using the calculated value of the function.

A displacement measurement method comprising:

• a step of generating a light beam having a predetermined wavelength width;
• a step of emitting the light beam from a sensor head through a member by which wavelength dispersion occurs according to a refractive index so that a focus is formed on a measurement target surface of a measurement target object;
• a step of receiving a light beam that is reflected at the measurement target surface within the emitted light beam;
• a step of calculating a distance between the sensor head and the measurement target surface based on a wavelength of the received light beam;
• a step of calculating a value of a function by serving the calculated distance as a value of a variable in the function using the distance as the variable;
• and
• a step of correcting the calculated distance using the calculated value of the function.