Device and method to calibrate or verify the displacement-measurement system of an instrumented indenter

A system comprising:

• a stage configured to support a sample and move the sample within an X-Y plane;
• an indenter including a punch having a longitudinal axis normal to the X-Y plane;
• an actuator coupled to the stage and/or the indenter and configured to cause displacement of the punch relative to the stage in a direction substantially parallel to the longitudinal axis of the punch;
• a force detector configured to output data representative of an applied force corresponding to mechanical response of the sample as a reaction to being contacted by the punch;
• a displacement detector configured to output data representative of a depth at which the sample is touched by the punch;
• an optical detector configured to output data representative of a relative depth between two or more positions of the sample;
• and
• a controller in electronic communication with the actuator, the force detector, the displacement detector, and the optical detector, the controller being configured to control the displacement of the punch relative to the stage and the force applied by the punch to the sample and receive the data output by the force detector, the displacement detector, and the optical detector;
• wherein the sample includes an inclined surface, the inclined surface being inclined in an X-direction of the X-Y plane;
• wherein the optical detector is configured to detect a relative depth between a first position and a second position on the inclined surface, the first position and the second position being offset in the X-direction of the inclined surface by a distance moved by the stage, and the controller is further configured to determine a slope of the inclined surface based on the relative depth between the first position and the second position and the distance moved by the stage from the first position to the second position;
• wherein the displacement detector is configured to detect a depth at which the sample is touched by the punch at a plurality of intermediate positions on the inclined surface, the plurality of intermediate positions being located between the first position and the second position in the X-direction, and the controller is further configured to:
• determine a calculated depth of the inclined surface at each of the plurality of intermediate positions based on the slope of the inclined surface and the distance moved by the stage;
• and
• compare the depth measured by the displacement detector at each of the plurality of intermediate positions to each corresponding calculated depth to verify accuracy of the displacement detector.