Stress visualization device and mechanical property value visualization device

A stress visualization device for tomographically visualizing stress in an object to be measured, the stress visualization device comprising:

• a light source configured to emit light;
• a polarizer configured to linearly polarize the light emitted from the light source;
• a beam splitter configured to split the linearly polarized light into a first beam directed to an object arm including the object and a second beam directed to a reference arm including a reference mirror;
• an optical modulator provided on the object arm which is controlled to adjust a polarization state of the linearly polarized light;
• an optical detection device configured to detect interference light, resulting from superimposition of object light reflected by the object and reference light reflected by the reference mirror, as an optical interference signal, and separate the interference signal into a horizontal polarization component and a vertical polarization component;
• a control computation unit connected to the optical modulator to adjust the polarization state by controlling the optical modulator, and configured to compute distribution of stress at cross-sectional positions, each defined by a position in a depth direction and a position in a direction orthogonal to the depth direction of the object, on a basis of a phase difference between the horizontal polarization component and the vertical polarization component of the interference signal detected by the optical detection device;
• and
• a display device connected to the control computation unit and configured to display tomographically visualized stress distribution of the object on a basis of a computation result of the control computation unit,
• wherein the control computation unit controls the optical modulator to change the polarization state to shift a phase of polarized light with which the object is irradiated, computes the phase difference for the interference signal obtained by each phase shift of the polarized light, computes spatial gradients of tomographic distribution of phase difference on a basis of the computed phase differences, and controls the visual display unit to visually display tomographic distribution of spatial gradient in association with tomographic distribution of stress on the display device.