Light microscopy remains the foundational tool for biological research and clinical diagnostics. The technology relies on the interaction of visible light with a specimen, utilizing a system of glass lenses to magnify images of small objects. The performance of these devices is governed by "Resolution"—the ability to distinguish two closely spaced points as separate entities—which is limited by the diffraction of light. According to Abbe’s Law, the maximum resolution of a standard light microscope is approximately 200 nanometers.

Modern systems have evolved from simple brightfield illumination to specialized techniques like Phase Contrast and Differential Interference Contrast (DIC). These methods allow for the visualization of live, unstained cells by converting phase shifts in light passing through a transparent specimen into brightness changes. For an overview of the technical specifications and configurations of modern optical systems, the Microscopy Devices Market documentation provides a breakdown of inverted, upright, and digital models. These advancements are essential for observing dynamic cellular processes without the need for toxic chemical fixatives.

Digital integration has further transformed optical microscopy. CCD and CMOS sensors have replaced the human eye as the primary detector, allowing for high-speed image acquisition and quantitative analysis. Software-driven deconvolution can now remove "out-of-focus" blur from images, pushing the boundaries of what can be captured with traditional optics. As these systems become more automated, they are increasingly used in high-throughput screening (HTS) for drug discovery and pathology.