Abstract
The digital light processing (DLP) technique is used to form images through the projector. A key device for the DLP is an array of micromirrors (digital micromirror device: DMD). Firstly, we illuminated microscopic specimens using a DMD. To this end, a light source and a concave mirror of a DLP projector were replaced with a diode laser and a dichroic mirror for effective excitation and detection of the fluorescence. With the modified DLP projector mounted in the place of the light source for a microscope with a x60 objective lens and an image-intensified camera, an epi-fluorescence image of the HeLa cells stained with tetramethylrhodamine was clearly observed. Under this condition, the illumination area could be modified freely by a personal computer. Individual micromirrors of the DMD changed the angle of reflection digitally and rapidly, thus formed pixels with a gray scale on the screen. We, next, attempted to employ a DMD as a novel scanner for the confocal microscope, since a single mirror in the DMD shared a function similar to the confocal pin hole. When micromirrors were controlled to form a light spot containing 5x5 pixels for spatial scanning, optical slicing was achieved in a 4 μm thickness. The thickness of optical slice was variable by changing the number of pixels in the scanning-spot. The plasma membrane and other cellular organelles may be distinguishable clearly by using this novel microscope system. [Jpn J Physiol 54 Suppl:S64 (2004)]
