The light path of a common optical microscope
1. An ordinary optical microscope is a precise optical instrument. Whereas simple microscopes in the past consisted of only a few lenses, currently used microscopes consist of a set of lenses. Ordinary optical microscopes can usually magnify objects 1500-2000 times. (1) The structure of the microscope The structure of the ordinary optical microscope can be divided into two parts: one is the mechanical device and the other is the optical system. Only when these two parts cooperate well can the microscope function. 1. The mechanical device of the microscope The mechanical device of the microscope includes the lens holder, the lens barrel, the objective lens changer, the stage, the pusher, the coarse motion screw, the fine motion screw and other components
(1) Mirror base The mirror base is the basic bracket of the microscope, which consists of two parts: the base and the mirror arm. The stage and the lens barrel are attached to it, and it is the basis for installing the components of the optical magnification system.
(2) Lens barrel The lens barrel is connected to the eyepiece on the top and the converter on the bottom to form a dark room between the eyepiece and the objective lens (installed under the converter). The distance from the trailing edge of the objective lens to the rear end of the lens barrel is called the mechanical barrel length. Because the magnification of the objective lens is relative to a certain length of the lens barrel. The change in the length of the lens barrel not only changes the magnification, but also affects the image quality. Therefore, when using a microscope, the length of the lens barrel cannot be changed arbitrarily. The standard barrel length of the microscope is set at 160mm internationally, and this number is marked on the housing of the objective lens.
(3) Objective lens converter The objective lens converter can be installed with 3-4 objective lenses, generally three objective lenses (low magnification, high magnification, oil lens). Nikon microscopes are equipped with four objective lenses. By turning the converter, any one of the objective lenses and the lens barrel can be connected as required to form a magnifying system with the eyepiece on the lens barrel.
(4) Stage There is a hole in the center of the stage, which is the light passage. There are spring specimen clamps and pushers on the stage, which are used to fix or move the position of the specimen, so that the microscopic object is just in the center of the field of view.
(5) The pusher is a mechanical device for moving the specimen. It is composed of a metal frame with two propelling gear shafts, one horizontal and one vertical. A good microscope has a scale scale engraved on the vertical and horizontal frame rods, which constitutes a very precise plane coordinate. Tie. If we need to observe a certain part of the examined specimen repeatedly, in the first examination, we can write down the value of the vertical and horizontal scales, and then move the pusher according to the value to find the position of the original specimen.
(6) Coarse-moving screw Coarse-moving screw is a mechanism that moves the lens barrel to adjust the distance between the objective lens and the specimen. In old-fashioned microscopes, the coarse screw is twisted forward, and the lens descends to approach the specimen. When inspecting a newly produced microscope (such as a Nikon microscope), twist the stage forward with the right hand to raise the stage to bring the specimen close to the objective lens, and vice versa to lower the specimen to leave the objective lens.
(7) Micro-movement screw The coarse-movement screw can only adjust the focal length roughly. To get a clear object image, it is necessary to use the micro-movement screw for further adjustment. The lens barrel moves 0.1 mm (100 microns) per revolution of the micro-spiral. The coarse and fine motions of the newer, higher-grade microscopes are coaxial. 2. The optical system of the microscope The optical system of the microscope is composed of a reflector, a condenser, an objective lens, an eyepiece, etc. The optical system enlarges the object and forms an enlarged image of the object.
to make objects slip past and not be found.
