The optical path of an ordinary optical microscope
The general optical microscope is a precision optical instrument. While simple microscopes used to consist of only a few lenses, the microscopes in use today consist of a set of lenses. An ordinary light microscope can usually magnify an object 1500-2000 times.
The construction of a microscope The construction of an ordinary optical microscope can be divided into two main parts: one is the mechanical device and the other is the optical system, which work well together in order to play the role of the microscope.
Mechanical device of microscope The mechanical device of microscope includes the lens holder, lens barrel, objective converter, carrier stage, pusher, coarse-action screw, micro-action screw and other parts.
(1) Mirror Holder The mirror holder is the basic support of the microscope and consists of two parts: the base and the arm. On it is connected to the carrier stage and the lens barrel, it is used to install the optical magnification system components of the foundation.
(2) Lens barrel The lens barrel is connected to the eyepiece on the top and the converter on the bottom, forming a darkroom between the eyepiece and the objective lens (mounted under the converter). The distance from the rear edge of the objective lens to the end of the barrel is called the mechanical barrel length. This is because the magnification of the objective lens is for a certain barrel length. Changes in the length of the lens barrel not only change the magnification, but also affect the image quality. Therefore, when using a microscope, the length of the lens barrel cannot be changed arbitrarily. The standard length of the microscope tube is set at 160mm, and this number is labeled on the housing of the objective lens.
(3) Objective converter The objective converter can be fitted with 3-4 objective lenses, usually three (low magnification, high magnification and oil lens). Nikon microscopes are equipped with four objective lenses. By rotating the converter, any one of the objective lenses can be connected to the lens barrel as required to form a magnification system with the eyepieces on top of the lens barrel.
(4) Stage The stage has a hole in the center of the stage for light passage. On the table is equipped with a spring specimen clip and pusher, its role is to fix or move the position of the specimen, so that the object of microscopy is located in the center of the field of view.
(5) pusher is a mechanical device to move the specimen, which is composed of a horizontal and a vertical two propulsion tooth axis of the metal frame, a good microscope in the vertical and horizontal frame bars are engraved with a graduated scale, constituting a very precise plane coordinate system. If we have to repeat the observation of a part of the specimen has been checked, in the * check, you can write down the value of the vertical and horizontal scales, and then move the pusher according to the value of the original specimen can be found in the position.
(6) coarse spiral coarse spiral is to move the barrel to adjust the distance between the objective lens and the specimen, the old microscope coarse spiral twisted forward, the lens down close to the specimen. Recently produced microscopes (such as Nikon microscopes) when the mirror, the right hand forward twisting the stage rise, so that the specimen close to the objective lens, and vice versa, the decline, the specimen out of the objective lens.
(7) Microscrew The coarse screw can only be used to adjust the focus loosely, to get a clear image, it is necessary to use the microscrew to make further adjustments. The microscrew moves the lens barrel 0.1 mm (100 µm) per revolution. Recently produced higher-grade microscopes of the coarse screw and micro screw is co-axial. The optical system of the microscope consists of a reflector, a condenser, an objective lens, an eyepiece, etc. The optical system magnifies the object and forms a magnified image of the object.
