A Compact and Low-Cost Optical Pickup Head-Based Optical Microscope

An optical pickup head (OPH) is a compact and low-cost but of high-precision optical system. In the past, it has been used for much scientific research besides optical disc storage, in particular, for the length-related measurements. In this paper, we propose a compact and low-cost OPH-based optical microscope (OM). A CMOS sensor disassembled from the web camera is fixed below the fold mirror of the OPH. The revised structure is simple and low cost but without permanently altering the original structure of the OPH. The user can choose operation modes of either the OPH or OM by a simple switching. We estimated that the optical magnification of the OM is 15.5X. The experimentally measured resolution of the OM is ~2 μm for the visible light, and it achieved diffraction limit for narrow-band light source. From the results of optical simulation, the main factor deteriorating the resolution is chromatic aberration. Astigmatic aberration is not important. Some plant cells investigation results using the microscope are also demonstrated in this paper.