Optical principles and accessories of optical microscopes
Optical principles
A microscope uses the magnification imaging principle of a convex lens to enlarge small objects that cannot be distinguished by the human eye to a size that the human eye can distinguish. The main purpose is to increase the opening angle of nearby small objects to the eye (objects with a large viewing angle are imaged on the retina over a larger area). ), and use the angular magnification M to represent their magnification capabilities. Because the opening angle of the same object to the eye is related to the distance of the object from the eye, it is generally stipulated that the magnification of the image at a distance of 25 cm from the eye (photopic distance) is the magnification of the instrument. When observing objects through a microscope, the viewing angle is usually very small, so the ratio of the viewing angles can be replaced by the ratio of its tangent.
The microscope consists of two converging lenses, and the optical path diagram is shown in the figure. Object AB passes through the objective lens and becomes a magnified inverted real image A1B1. A1B1 is located inside the object focal length of the eyepiece. After passing through the eyepiece, it forms an enlarged virtual image A2B2 at the clear vision distance.
Accessories
With the development of modern biotechnology and the improvement of people's requirements for microscopes, a single optical microscope imaging system is far from meeting people's requirements for microphotography. The advent of digital microscopes marks the entry of optical microscopes into a new digital era. The digital microscope not only combines the good imaging characteristics of the optical microscope, but also perfectly combines it with advanced photoelectric conversion technology and liquid crystal screen technology, so that the microscope not only has the ability of microscopic observation, but also realizes the digital storage and storage of microscopic images. transmission.
However, the high cost of digital microscopes has not allowed them to be widely used, and a new type of microscopic digital product, the microscopic digital camera, has also emerged. As a dedicated microscopic digital camera, the microscopic digital camera can be easily linked to any microscope to transform an optical microscope into a digital microscope.
As an essential accessory for optical microscopes, microscopic digital cameras are also divided into many different levels according to different needs. Some are more suitable for those with higher image requirements, and some are more suitable for general needs. As a convenient and fast microscopic camera system, the microscopic digital camera will be greatly used.
The accessories of optical microscopes include eyepieces, objectives, light sources, etc. Of course, with the development of science and technology, optical microscopes are gradually equipped with camera systems, so that they can be displayed on the monitor, making viewing more convenient.
In addition, the light source of the light source microscope is also very important. When equipped, the light source can include a ring light source or a clip-on light source. The bases of optical microscopes are also different. Some are made of plastic, and some are made of alloy. The better ones are made of alloy, which is not easy to deform. The magnification factors are also different, some can continuously change the magnification, and some have only one magnification, or two magnifications.
