Abstract: In a speckle interferometer apparatus 2, an optical member mounting device 10 mounted with optical members including a pair of luminous flux outputting devices 9a, 9b, 9c, 9d is disposed on the object side of a main unit of an imaging device 3 while being separated from the imaging device 3. A light-transmitting area 14 is formed between the pair of luminous flux outputting devices 9a, 9b, 9c, 9d so as to transmit therethrough interference light from an object surface.

Abstract: In a speckle interferometer apparatus 2, an optical member mounting device 10 mounted with optical members including a pair of luminous flux outputting devices 9a, 9b, 9c, 9d is disposed on the object side of a main unit of an imaging device 3 while being separated from the imaging device 3. A light-transmitting area 14 is formed between the pair of luminous flux outputting devices 9a, 9b, 9c, 9d so as to transmit therethrough interference light from an object surface.

Abstract: An oblique incidence interferometer capable of fringe scanning by use of a fringe scan drive association with a first or second diffraction grating member of the interferometer to drive the associated grating member step by step over a micrometric distance in a direction perpendicular to a path of light in travel in a straightforward direction. Laser light from a light source 20 is diffracted into a zero order diffraction wave L1 in travel in a straightforward direction and a +1 order diffraction wave L2 by a first diffraction grating member 26 of a grating assembly 41. The grating assembly 41 is vertically movably supported on a surface plate 42 by a pair of level support members 43 each having a stratified leaf spring structure. The grating assembly 41 sits on a piezoelectric actuator 45 which serves as a fringe scan drive for driving the first diffraction grating member 26 over a micrometric distance in the vertical direction.

Abstract: A .lambda./4 plate is inserted into and retracted from an optical path of polarized light, thereby making it possible to select whether a noise component due to the stress strain within a test object is to be presented in fringes or not. As an operator operates an operation mechanism for a .lambda./4 plate (4), the .lambda./4 plate (4) is inserted into the optical path when a laser beam (2) should be turned into circularly polarized light, whereas the .lambda./4 plate (4) is retracted out of the optical path when the laser beam (2) should be turned into linearly polarized light.