Definition
Stereo microscope, also known as solid microscope or stereo microscope, is an upright microscope that uses optical principles to produce three-dimensional stereo vision. Its imaging characteristics are long working distance and large depth of field, and the sample usually does not need to be prepared complicatedly, and can be directly observed and operated at macroscopic or low magnification.
Principle
The optical design of stereo microscopes is based on the Greenop principle or the conjugate plane principle, which captures images of samples from different angles through two independent optical paths. After passing through the objective lens, the light is divided into two paths by a set of prisms or lens systems, and enters the left and right eyepieces respectively. The observer's eyes receive images with small parallax at the same time, and the brain fuses to form a three-dimensional image with depth perception. The magnification is usually continuous magnification, and the total magnification calculation follows the following relationship: total magnification = objective magnification × magnification factor × eyepiece magnification. Some systems can also be expanded with additional auxiliary objectives or camera interfaces.
Measurement method
In measurement applications, stereo microscopes are often combined with eyepiece micrometers or digital imaging systems for dimensional measurement. Before use, the system needs to be calibrated with a standard scale to determine the actual length of each index at the current magnification. For the measurement of 3D topography, the method of focusing clarity layer by layer scanning or with dual optical path phase difference analysis can be used. Modern digital stereo microscopes can quantitatively analyze multi-point distances, angles, areas and contours through software, taking into account system errors and calibration cycles.
Influencing factors
The imaging quality and measurement accuracy of stereo microscopes are affected by a variety of factors. Optical factors include objective lens resolution, aberration correction level, field of view flatness, and illumination uniformity. Mechanical factors involve multiplier repeatability, stage stability, and focusing mechanism accuracy. Environmental factors such as vibration and ambient light interference may affect observation. The color, reflectivity, transparency, and flatness of the sample itself also play a role in the imaging effect. Operator technical proficiency and visual adaptability are also aspects to consider in practical use.
Application
Stereo microscopes have a wide range of uses in several fields. In the electronics manufacturing industry, it is used for circuit board soldering inspection and component assembly. In the field of life sciences, assist in dissection, microsurgery and specimen screening. Used in materials science to observe fractures, crystal structures, or surface coatings. The field of forensic appraisal can be used for document inspection and trace analysis. In addition, it is also often used in scenarios such as cultural relics restoration, jewelry appraisal, precision assembly and educational demonstrations. Its non-destructive, real-time stereo vision makes it an effective tool for observation of macroscopic and microscopic junction areas.
Selection
Technical parameters and application requirements should be comprehensively considered when selecting. In terms of optical performance, the field of view, working distance, resolution and depth of field should be evaluated to meet the requirements of sample observation. The mechanical structure needs to pay attention to the zoom mode, focus feel and system stability. The selection of lighting system should consider the characteristics of the sample, and there are common configurations such as ring light, coaxial light, and oblique lighting. If recording or analysis is required, it is necessary to examine the compatibility of the image interface and the scalability of the software functions. Ergonomic designs such as eyepiece inclination and interpupillary distance adjustment range affect the comfort of use. In addition, ease of maintenance, accessory availability, and long-term cost of use should also be within the scope of decision-making.