Share the types of light microscopes
1. Dark Field Microscopy
Dark field microscope is a kind of optical microscope, also called ultramicroscope. There is a light shield in the center of the condenser of a dark field microscope, so that the illumination light does not directly enter the objective lens, and only the light reflected and diffracted by the specimen is allowed to enter the objective lens, so the background of the field of view is black, and the edge of the object is bright. of. Microparticles as small as 4-200nm can be seen with this microscope, and the resolution can be 50 times higher than that of ordinary microscopes.
2. Phase-contrast microscopy
The structure of the phase contrast microscope: the phase contrast microscope is a microscope that applies the phase contrast method. Therefore, the following accessories are added to the usual microscope: an objective lens equipped with a phase plate (phase annular plate), and a phase difference objective lens. Condenser with phase ring (annular slit plate), phase difference condenser. Monochromatic Filter - (Green).
The monochromatic filter is a green filter with a center wavelength of 546nm (nanometer). It is usually observed with a monochromatic filter. The phase plate shifts 90° to see the phase of the direct light at a specific wavelength. When a specific wavelength is required, an appropriate filter must be selected, and the contrast is improved when the filter is inserted. In addition, the center of the phase annular slit must be adjusted to the correct orientation before it can be operated, and the centering telescope is the part that plays this role.
3. Video microscope
The earliest prototype should be a camera-type microscope. The image obtained under the microscope is projected onto a photosensitive photo through the principle of small hole imaging, so as to obtain a picture. Or directly dock the camera with the microscope to take pictures. With the rise of CCD cameras, microscopes can transfer real-time images to TVs or monitors for direct observation, and can also be photographed by cameras. In the mid-1980s, with the development of the digital industry and the computer industry, the functions of the microscope were also improved through them, making it easier and easier to operate. By the end of the 1990s, with the development of the semiconductor industry, wafers required microscopes to bring more coordinated functions. The combination of hardware and software, intelligence, and humanization made microscopes develop even more in the industry.
4. Fluorescence Microscopy
A microscope that uses ultraviolet light as a light source to make the irradiated object emit fluorescence.
Fluorescence microscope principle:
Light source: A light source radiates light of various wavelengths (from ultraviolet to infrared).
Excitation filter light source: through the specific wavelength of light that can cause the specimen to produce fluorescence, while blocking light that is useless for exciting fluorescence.
Fluorescent specimens: generally stained with fluorescent dyes.
Blocking filter: block the excitation light that is not absorbed by the specimen and selectively transmit the fluorescence, and some wavelengths are selectively transmitted in the fluorescence.
5. Polarizing microscope
Polarizing microscopy is a type of microscope used to study so-called transparent and opaque anisotropic materials. All substances with birefringence can be clearly distinguished under a polarizing microscope. Of course, these substances can also be observed by staining, but some of them are impossible and must be observed using a polarizing microscope.
6. Ultrasonic microscope
The characteristic of ultrasonic scanning microscope is that it can accurately reflect the interaction between the sound wave and the elastic medium of the tiny sample, and analyze the signal fed back from the inside of the sample. Each pixel on the image (C-Scan) corresponds to the The signal feedback on a two-dimensional space coordinate point at a certain depth in the sample, the Z.A sensor with good focusing function can transmit and receive acoustic signals at the same time. A complete image is obtained by scanning the sample point by point and line by line. The reflected ultrasound waves are given a positive or negative amplitude so that the time of signal travel can be used to reflect the depth of the sample. A digital waveform on the user's screen shows the received feedback (A-Scan). Set the corresponding gate circuit, and use this quantitative time difference measurement (feedback time display), you can choose the sample depth you want to observe.
7. Dissecting Microscope
Dissecting microscopes, also known as solid microscopes, stereo microscopes or stereo microscopes, are microscopes designed for different work needs. When observing with a dissecting microscope, the light entering the two eyes comes from an independent path, and the two paths only have a small angle, so when observing, the sample can present a three-dimensional appearance. There are two types of light path designs for dissecting microscopes: The Greenough Concept and The Telescope Concept. Dissecting microscopes are often used for surface observation of some solid samples, or for work such as dissection, clock making, and small circuit board inspection.
8. Confocal Microscopy
The probe light emitted from a point light source is focused on the observed object through the lens. If the object is just in focus, the reflected light should converge back to the light source through the original lens. This is the so-called confocal, or confocal for short. A laser scanning confocal microscope [Confocal Laser Scanning Microscope (CLSM or LSCM)] adds a dichroic mirror to the optical path of the reflected light, refracting the reflected light that has passed through the lens to other directions, and at its focus There is one with a pinhole (Pinhole), the small hole is located at the focal point, behind the baffle is a photomultiplier tube (photomultiplier tube, PMT). It can be imagined that the reflected light before and after the focus of the detection light passes through this set of confocal system, but cannot be focused on the small hole, and will be blocked by the baffle. The photometer then measures the intensity of reflected light at the focal point. Its significance is: a translucent object can be scanned in three dimensions by moving the lens system.
9. Metallographic microscope
Metallographic microscope is mainly used to identify and analyze the internal structure of metals. It is an important instrument for metallographic research and key equipment for industrial departments to identify product quality. The instrument is equipped with a camera device that can capture metallographic images and analyze them. Maps can be measured and analyzed, and images can be edited, output, stored, and managed. There are many domestic manufacturers with a long history.
10. Biological microscope
Biological microscopes are used to observe and study biological slices, biological cells, bacteria, living tissue culture, fluid precipitation, etc., and can observe other transparent or translucent objects, powders, fine particles and other objects. Biological microscopes are also necessary inspection equipment for food factories and drinking water factories to do QS and HACCP certification.
