Apparatus for determination of elastic isodynes and of the general state of birefringence whole field-wise using the device for birefringence measurements in a scanning mode (isodyne polariscope)

Claim 1

Apparatus for the determination of elastic isodynes, photoelastic isodynes, and of general and particular states of optical anisotropy, in solid and liquid birefringent bodies, comprising: (1) a source of radiant energy producing a single narrow collimated radiation beam called the primary light beam; (2) means to circularly or linearly polarize and adjust the plane of vibration of the said primary light beam; (3) means to guide the said primary light beam into the said birefringent body along any selected direction and at any position; (4) means for selecting sheets of radiant energy consisting of light beams scattered in the said birefringent body along the path of the said primary light beam in directions close to normal to the said primary light beam at each scattering point and inclined to the plane of measurement at such angles that the intensities of the said scattered light beams carry directly optimal information on the state of optical anisotropy (birefringence) at the said scattering points in the said body; (5) means for isolation of a single sheet of scattered light; (6) means for secondary selecting and focusing of selected sheets of scattered light which transmits and focuses only those scattered light beams within particular light sheets which are scattered in the direction normal to the line of measurement; (7) means for optical noise reduction in the selected light sheets, which eliminates the background noise and transmits only those light beams which are scattered perpendicularly from the primary light beam, and which are focused by the means for secondary selecting; (8) means for producing real images of the distribution of the scattered light intensities along the path of the primary light beam within the plane of measurement using any of the said scattered light sheets, the optic axis of which is perpendicular both to the measurement plane and to the image plane; (9) means for recording or storing the said images of the light intensity distribution along the path of the primary light beam produced by the selected scattered light sheet when the primary light beam scans the plane of measurement and produces the image of the isodyne field; (10) means for electronic numerical processing and evaluation of information supplied by the recorded light intensity distribution at the plane of measurement, called isodyne image processor; (11) means for positioning and continuous displacing in horizontal and vertical directions the isodyne scanner, consisting of the mechanically and optically connected means (1) to (5), called driving unit; (12) means to eliminate refraction of the primary beam at the boundary of the object being investigated, called immersion tank.