Encyclopedia of Microscope Types
It is mainly divided into several categories: digital microscope, measuring microscope, metallographic microscope, three-dimensional video microscope, biological microscope, stereo microscope, industrial camera, industrial lens, microcirculation detector, and a drop of blood detector. The products are widely used in precision Industry, medicine, teaching, health care and other fields.
1. Bright field observation
2. Relief phase contrast microscope (RC)
3. Differential interference contrast DIC
4. Dark field observation
5. Polarizing microscope
6. Phase contrast
7. Fluorescence Microscopy
The above lists 7 common methods of observing microscopes. Let's talk about the differences between each method and how we should choose.
1) Let’s look at a microscope inspection method that everyone is familiar with—bright field microscope inspection, which can be performed by all microscopes;
2) The phase contrast microscope uses the difference in optical path of the object to be inspected, that is, effectively uses the interference phenomenon of light to change the phase difference indistinguishable by the human eye into a resolvable amplitude difference, even for colorless and transparent substances can also become clearly visible;
3) Differential interference microscopy uses a special Wollaston prism to decompose the light beam. The vibration directions of the split beams are perpendicular to each other and the intensity is equal, and the beams pass through the object at two points that are very close to each other, and there is a slight difference in phase. Since the split distance between the two light beams is extremely small, there is no double image phenomenon, so that the image presents a three-dimensional three-dimensional feeling;
4) Dark field is actually dark field illumination. Its characteristics are different from those of bright field. It does not directly observe the light of illumination, but observes the light reflected or diffracted by the object under inspection. Therefore, the field of view becomes a dark background, while the object under inspection presents a bright image. The special accessory required for m..m dark field observation is a dark field condenser;
5) Polarizing microscope is a microscope for identifying the optical properties of the fine structure of substances. All substances with birefringence can be clearly distinguished under a polarizing microscope. Of course, these substances can also be observed with dyed hair, but some of them are impossible and must be observed using a polarizing microscope;
6) In 1975, Dr. Robert Hoffman invented it. In 2002, when the patent expired, various microscope manufacturers launched RC technology products named after themselves. Different shadows, so that the surface of transparent specimens produces light and dark differences, increasing the contrast of observation
7) Fluorescence microscopy is to irradiate the object stained with fluorescein with short-wavelength light, so that it is excited to produce long-wavelength fluorescence, and then observed.
Second, the working distance of the objective lens:
The working distance of the microscope refers to the working distance of the objective lens. The larger the magnification, the larger the numerical aperture, and the shorter the working distance. . The use and classification of microscopes At present, optical microscopes have evolved from traditional biological microscopes to many types of special microscopes. According to their imaging principles, they can be divided into:
① Geometric optical microscope: including biological microscope, epi-light microscope, inverted microscope, metallographic microscope, dark field microscope, etc.
②Physical optical microscope: including phase-contrast microscope, polarized light microscope, interference microscope, phase-contrast polarized light microscope, phase-contrast interference microscope, phase-contrast fluorescence microscope, etc.
③ Information conversion microscope: including fluorescence microscope, microspectrophotometer, image analysis microscope, acoustic microscope, photographic microscope, television microscope, etc.
1. The purpose of the microscope:
a Biological microscope: Generally speaking, microscopes can be divided into two categories: stereo microscopes and biological microscopes. Due to different uses and different requirements, many branches have been produced, but the basic principle is still the same. Polarization, phase contrast, transmission and epimetry, etc. still belong to biological microscopes.
b Stereo microscope: Also known as dissecting microscope, solid microscope and stereo microscope, it is a microscope with many uses. It is easy to operate, does not have high requirements for specimens, has a long working distance, and has a strong sense of three-dimensionality when observing. It can observe real objects, and can also perform some operations on specimens while observing. Instead of slicing specimens like biological microscopes, slicing requires corresponding techniques and equipment. Therefore, stereo microscopes are widely used in the fields of microelectronics, precision instrumentation assembly and maintenance, and micro-carving. It is widely used in anatomical operations and microsurgery (currently classified as operating microscopes) in the fields of biology and medicine. The light source used in the fields of biology and medicine can only use cold light sources (optical fibers); it is used in industries for tiny parts and Integrated circuit observation, assembly, inspection and other work.
c metallographic microscope: Many people like to write it as "golden image microscope". Metallographic microscope is a microscope specially used to observe the metallographic structure of opaque objects such as metals and minerals. These opaque objects cannot be observed in ordinary transmission microscopes, so the main difference between phase and ordinary microscopes is that the former is illuminated with reflected light, while the latter is illuminated with transmitted light. In a metallographic microscope, the illumination beam is projected from the direction of the objective lens to the surface of the object to be observed, reflected by the object surface and then returned to the objective lens for imaging. This reflected lighting method is also widely used in the detection of integrated circuit silicon wafers.
2. Light source: The light sources for microscopes mainly include: fluorescent lamps, LED lamps, halogen lamps, incandescent lamps, cold light sources (fiber optics), etc., but there are many varieties on the market, so good and bad are mixed. Pay more attention when purchasing: Polarizing microscopes It is a microscope used to study so-called transparent and opaque anisotropic materials (identify the optical properties of the fine structure of substances). All substances with birefringence can be clearly distinguished under a polarizing microscope. Of course, these substances can also be observed by staining, but some are not possible, and a polarizing microscope must be used.
