Since the dawn of human civilization, we have sought to understand the composition and workings of the world around us. Yet, the naked eye can only perceive so much. It was the invention of the microscope that truly opened the door to exploring the microscopic universe. As one of the core tools of modern scientific research, the microscope has not only profoundly transformed fields such as biology, medicine, and materials science but has also continuously driven technological innovation itself.

The development of the microscope dates back to the late 16th century. In 1590, Dutch spectacle maker Zacharias Janssen constructed the first compound microscope. Although its magnification was less than 10x, it laid the foundation for future advancements. In the 17th century, Antonie van Leeuwenhoek, using a self-made single-lens microscope, was the first to observe microorganisms such as bacteria, red blood cells, and sperm, earning him the title "Father of Microbiology."

In the 19th century, German optical scientist Ernst Abbe proposed the theoretical resolution limit of optical microscopes, providing a scientific basis for microscope design. The 1930s saw the invention of the electron microscope, which broke the resolution barrier of optical microscopes and made it possible to observe atomic structures. In recent years, the emergence of super-resolution fluorescence microscopy has enabled scientists to reveal life processes at the molecular level, a breakthrough that earned its inventors the Nobel Prize in Chemistry in 2014.

Based on their imaging principles, microscopes can be broadly categorized as follows:

Using visible light to observe samples, these are widely applied in medical diagnostics, biological research, and education. Examples include upright microscopes, inverted microscopes, and confocal microscopes.

Utilizing electron beams instead of light for imaging, these achieve resolutions at the nanoscale. Scanning electron microscopes (SEM) are used for surface morphology analysis, while transmission electron microscopes (TEM) can observe internal structures of materials.

These employ physical probes to scan sample surfaces, achieving atomic-level resolution. Examples include atomic force microscopes (AFM) and scanning tunneling microscopes (STM).

Breaking the Abbe limit, these push the resolution of optical microscopes to the nanoscale. Examples include STED (Stimulated Emission Depletion Microscopy) and PALM (Photoactivated Localization Microscopy).

In recent years, microscope technology has continued to evolve toward higher resolution and greater intelligence. For instance:

: Deep learning algorithms are now used to enhance image quality, automatically identify cellular structures, and even predict sample properties.

: New microscopes enable long-term, low-phototoxicity observation of living cells, allowing scientists to track biological processes in real time.

: The combination of microscopy with physics, chemistry, and computational science has led to revolutionary methods such as cryo-electron microscopy (Cryo-EM), driving advancements in structural biology.

The microscope is more than just a tool—it is an expander of human cognitive boundaries. It has revealed that a single drop of water contains an entire ecosystem and that the interior of a cell operates with complexity rivaling that of a city. From uncovering disease-causing microorganisms to observing quantum phenomena, the microscope continues to deepen our understanding of natural laws.

As scientists often say, "The microscope has taught us that the visible world is only a small part of reality." As science and technology continue to advance, the microscope will remain the "scientific eye," guiding humanity to explore ever more unknown realms.