STRUCTURED ILLUMINATION MICROSCOPE, OBSERVATION METHOD, AND MICROSCOPE CONTROL PROGRAM

Provided is a structured illumination device capable of switching structured illumination at high speed. A structured illumination microscope (2) includes: a brancher (13) that includes a first substrate on which a plurality of pixel electrodes are provided; a second substrate opposed to the first substrate; and a ferroelectric liquid crystal disposed between the first substrate and the second substrate, and branches light from a light source (20) into diffracted light beams; an illumination optical system (14) that illuminates a sample with interference fringes formed by at least some of the diffracted light beams; an imaging device (3) that forms an image of the sample irradiated with the interference fringes; a demodulator (4); and a controller (15) that controls a direction and a phase of the interference fringes. In one frame period during which the imaging device takes the image, the controller (15) applies a first voltage pattern and a second voltage pattern obtained by inverting the first voltage pattern to at least some of the pixel electrodes.