Quick Overview
Infinite. Total Magnification: 50-1000X. 10X Adjustable Eyepiece. 5X 10X 20X 50X 100X Infinity Plan Semi-Apochromatic Polarizing Objective. Standard Coupler: 0.5X. Eye Tube Angle: 0-35°. Eyepiece Field of View: Dia. 25mm. Illumination Type: Halogen Reflection Light. Coaxial Reflection Light Type: Bright Field.
Nexcope-NP900RF-Trinocular Trinocular Reflected Polarizing Microscope
Optical System Specifications
| Optical System | Infinite |
| System Optical Magnification | 50-1000X |
| Trinocular Optical Magnification | 2.5-50X |
| Total Magnification | 50-1000X |
| Standard Eyepiece | 10X Adjustable Eyepiece |
| Standard Objective | 5X 10X 20X 50X 100X Infinity Plan Semi-Apochromatic Polarizing Objective |
| Standard Coupler | 0.5X |
| System Field of View | Dia. 0.25-5mm |
Microscope Eyepiece Tube
| Eye Tube Optical System | Infinite |
| Eye Tube Type | For Compound Microscope |
| Eye Tube Adjustment Mode | Siedentopf |
| Eye Tube Angle | 0-35° |
| Erect/Inverted Image | Inverted Image |
| Eye Tube Rotatable | 360° Degree Rotatable |
| Interpupillary Adjustment | 47-78mm |
| Eye Tube Inner Diameter | Dia. 30mm |
| Eye Tube Diopter Adjustable | Not Adjustable |
| Image Port Switch Mode | 0/100 Switch Trinocular |
Eyepiece
| Eyepiece Type | Adjustable Eyepiece |
| Eyepiece Optical Magnification | 10X |
| Plan Eyepiece | Plan Eyepiece |
| Eyepiece Size for Eye Tube | Dia. 30mm |
| Eyepiece Field of View | Dia. 25mm |
| Eyepoint Type | High Eyepoint Eyepiece |
| Eyepiece Diopter Correction | ±5° |
Nosepiece
| Inward/Outward Nosepiece | Nosepiece Inward |
| Number of Holes on Nosepiece | Sextuple (6) Holes |
| Nosepiece Switch Mode | Manual |
| Nosepiece Screw Thread for Objective | M25x0.75mm |
| Nosepiece with Slot | Slot with Analyzers / D.I.C. |
Microscope Stand
| Base Type | Illumination Base |
| Base Shape | T-shape |
| Focus Mode | Manual |
| Coarse/Fine Focus Type | Coaxial Coarse/Fine Focus |
| Focus Distance | 35mm |
| Fine Focus Travel Distance | Same as Focus Distance |
| Fine Focus Minimum Scale | 1μm |
Microscope Stage
| Rotary Stage Top Diameter | Dia. 190mm |
| Rotary Stage Click Stop | 360° Click Stop Function |
| Rotary Stage Angle Graduate | 360°Graduated in 1° increments |
| Rotary Stage Lock | Lockable in Any Position |
Microscope Illuminator
| Illumination Type | Halogen Reflection Light |
| Coaxial Reflection Light Type | Bright Field |
| Coaxial Reflection Illuminator Light Source Type | Halogen Light |
| Lamp House Light Center Adjustable | Lamp House Light Center Adjustable |
| Polarizer Rotation Range | 360° |
| Gypsum Test Plate | 1/4 Wavelength Retardation Plate Optical Path Difference 137nm |
| Mica Test Plate | 1/4 Wavelength Retardation Plate Optical Path Difference 530nm |
| Quartz Wedge | 1/4 Wavelength Retardation Plate |
Other Parameters
| Color | White |
Series
| NP900 | Nexcope-NP900RF-Trinocular |
Technical Info
Instructions
Polarizing MicroscopeClose Λ
| Polarizing microscope, also known as polarized microscope, is widely used in geology and mining, and is therefore often referred to as the polarized metallographic microscope or geology microscope. The polarized light is used to observe the phenomenon of "optical anisotropy" (refers to the uneven spatial distribution of optical properties) and measure the relevant parameters, the ordinary light of the microscope is changed to polarized light, to this end, the polarized light attachment device is added. In some general-purpose microscopes, two polarizing plates are added: a polarizer is added to the incident light path, and an analyzer is added to the observing optical path to obtain polarized light illumination, which becomes a polarizing microscope. Polarizing microscope is often used for research in the field of opaque objects such as minerals, general biology, and medicine. Dedicated transmissive or reflective polarizing microscopes, their series of components, including eyepieces, objectives, stages, microscope tubes with Bertrand Lens, condensers and compensators, are all designed to meet specific needs. The polarizing microscope can perform single-polarization observation, orthogonal polarization observation, conoscopic observation, and identification of birefringent materials by the polarization characteristics of light for crystallography research, stress science and research of other disciplines. At the same time, it is also widely used in the fields of minerals, petroleum, semiconductor industry, chemistry, etc., as well as medicine, biology and botany. Polarizing microscopes can be divided into reflection, transmitted, and reflective and transmitted microscopes. The main special structures and accessories of polarizing microscopes include polarizers, analyzers, and some polarizing accessories. Polarizer and analyzer are the most important polarizing devices for polarized microscopes. They were originally composed of Nicola Prism. Nowadays, artificial polarizers, PL for short, are mostly used. Light that vibrates in a certain direction can pass through selectively, and becomes linearly polarized light that vibrates in a straight line. What is mounted between the light source and the observed sample is called polarization lens (polarizer), also known as lower polarization lens. What is mounted between the objective lens and the eyepiece is called analyzer, also known as lower analyzer, can change direction by rotation and is marked with a rotation angle scale. The light source of the polarizing microscope usually uses full-color light. Generally, a common white light source can be used. If necessary, monochromatic light can be used, or a color filter can be added, so that the speed, refractive index, and interference phenomenon of the light differ depending on the wavelength. Polarizers usually filter out most of the light, so polarized microscopes must use a relatively strong light source. For objective lenses of polarized light microscopes, a "stress free" achromatic objective lens should be used, usually marked with a "P" mark, especially higher power apochromatic and semi-apochromatic objective lens, as they themselves contain fluorite components, which can cause polarization to form interference. The nosepiece is usually mounted with an adjusting device to compensate the eccentric position of each objective lens, so that the field center of the objective lens is aligned with the center of the microscope stage, and for some microscopes, their rotating table is mounted with centering knob. The eyepiece of polarizing microscope requires the use of an eyepiece with a cross-hair reticle. The built-in cross-line scale is used in combination with a polarizing microscope-specific "polarizing tube" to adjust the center position of the centering nosepiece, so that the target crystal sample is rotated at the intersection of the cross for observation. The Bertrand Lens, also known as the B Lens, is located between the eyepiece and the analyzer, and is combined with the eyepiece to form a set of telescopes that can be pulled out from the optical path and centered for focus. When used in conic optical detection system, conic optical lens can be added on the basis of orthogonal polarization for interferogram observation The stage of the polarizing microscope is a kind of circular stage that can rotate 360°. It can be scaled around, and some have a main scale and a sub-scale. It can measure the rotation degree and the division number of the specimen details, and some also have a rotational reading that measures the solid angle. Some stages are also provided with a 45° positioning device from any angle, so that the extinction position and the diagonal position can be judged from the hand feeling. For condenser of polarized light microscopes, it is required that the lens has no stress. In order to achieve parallel polarized light, a swing out condenser that can push out the upper lens should be used. Use of Polarized Microscope The principle of polarized microscope is mainly to use the characteristics of the optical "anisotropy". When a beam of light is incident on an anisotropic crystal, it is split into two beams of light propagating in different directions. This phenomenon is called birefringence. Birefringence is a basic property of crystals, such as calcite in uniaxial crystals, quartz lamps, mica in biaxial crystals, gypsum crystals, and various kinds of biocrystals. When the light passes through the birefringent body, the vibration directions of the two polarized lights are different depending on the type of the object. A polarizing microscope can detect the single refraction (isotropic) or birefringence (anisotropic) of a substance. When the light emitted by the light source passes through the two polarizers, if the directions of the polarizer and the analyzer are parallel to each other, the linearly polarized light formed by the polarizer can completely pass, and the field of view is the brightest at this time. If the two are perpendicular to each other, the light cannot pass at all, and the field of view is completely dark at this time. This vertical position of the polarizing plate and the analyzing plate is called "orthogonal analyzer position"; if the two are tilted, only a part of the light is passed, and the field of view has medium brightness. Single polarized specimens does not use the above-mentioned analyzer, the condenser and the Bertrand Lens , but only the polarization observation method wherein a polarizer is used to observe in one direction, and it is often used to observe the topographical features of minerals, such as crystallinity, cleavage, color, matte and bulge Cross polarized specimens, also known as "positive image inspection", is that under the cross detection position, there is no light transmitted, and the field of view is dark. If the object to be inspected is optically isotropic (single refractor), the field of view of the rotating stage will still be dark; if the object to be inspected has birefringence characteristics or contains a material having birefringence characteristics, the field of view of the position with birefringence characteristics will become brighter, this is because the linearly polarized light emitted from the polarizer generates two types of linearly polarized light with different vibration directions after entering the birefringent body. When these two kinds of light pass through the analyzer, as the other beam is not orthogonal to the polarization direction of the analyzer, the image can be seen by the human eye through the analyzer. When rotating the stage while the birefringent is at the quadrature analyzer position, the image of the birefringent has four times of changes in brightness in the 360° rotation, and darkens every 90°. The darkened positions are where the two vibration directions of the birefringent coincide with the vibration directions of the two polarizers, which are called "extinction positions". When rotated 45° from the extinction position, the object to be observed becomes the brightest, which becomes the “diagonal position”. This is because when the polarized light reaches the object while deviating from 45°, part of the light decomposed can pass through the analyzer, so it is bright. Conoscopic observation is commonly used for the discrimination of uniaxial crystals, biaxial crystals, confirmation of the cutting surface orientation and axial direction, as well as discrimination of normal crystals and negative crystals, etc. Conoscopic observation is to illuminate the sample with a large numerical aperture of light in the observation while the polarized microscope is at its quadrature analyzer position, and use the objective lens to focus with also a large numerical aperture in order to see the information of the light passing through the sample in all directions through the back focal plane of the objective lens. This method of not observing the sample itself directly, but by observing the back focus plane of the objective lens is called conoscopic microscopic examination. Interference color observation is to observe the birefringent body with mixed light of various kinds of different wavelengths as the light source in the case of quadrature analyzer position of the polarized microscope. When rotating the stage, not only the brightest diagonal position in the field of view appears, but also the color, these colors can help us detect more chemical components of the specimen. The reason for the appearance of color is mainly caused by the interference color (it is also possible that the object itself being inspected is not colorless and transparent). The distribution characteristics of the interference color are determined by the type of the birefringer and its thickness, which is due to the dependence of the corresponding delay on the wavelength of the light of different colors. If the delay of a certain area of the object to be inspected is different from the delay of another area, the color of the light passing through the analyzer will be different. Polarized Microscope Adjustment Method 1. Polarized microscope rotating platform and the objective optical axis adjustment center position Place a slice on the rotary table and find a small feature point in the slice that coincides with the center of the crosshair of the eyepiece. Turn the work table. If the center of the optical axis of the objective lens is inconsistent with the center of the table, then the position of the feature point will rotate away from the center of the crosshair around a circle, and the center of the circle is the center of the workbench. Adjust the nosepiece, or the two adjustment screws on the platform, so that the objective optical axis coincides with the center of the rotary table. 2. Adjust the Position of the Polarizer First, the polarizer should be calibrated. The polarized microscope sometimes uses only one polarizer to observe, and it must be confirmed that the vibration direction of the polarizer is consistent with the horizontal and vertical directions of the eyepiece crosshair. Adjust the vibration direction of the polarizer and the crosshair of the eyepiece reticle: find a piece of cleavage and clear black mica sheet, exit the above-mentioned analyzer, and use only the polarizer below to observe, parallel the cleavage seam of the black mica with the horizontal wire of the crosshair of the eyepiece reticle. At this time, the black mica is light yellow, rotate the polarizer, when the color of the black mica reaches the darkest, the cleavage direction is consistent with the vibration of the polarizer, by this time, its scribe line should be aligned to 0° or 180°. 3. The polarizer and the analyzer should be in an orthogonal position, which is consistent with the horizontal and vertical directions of the eyepiece crosshair. After the direction of the lower polarizer is calibrated, remove the black mica sheet, push it into the upper analyzer, and observe whether the field of view is in the extinction state. If it is completely dark, it indicates that the vibration directions of the analyzer are orthogonal to each other, otherwise it must be calibrated, that is, turn the upper analyzer to the darkest point in the field of view. When turning, the stop screw of the upper polarizer must be loosened first, and then tighten it after calibrating. Polarized light microscopes must be kept clean, as most of the material around us is birefringent, such as dust in the air and the mineral dust in the soil, the textile fibers in our clothing, etc., which can interfere with the polarization effect. For more precautions on the use of polarized light microscopes, please refer to the Biological Microscope on the BoliOptics website. |
InfiniteClose Λ
| Microscopes and components have two types of optical path design structures. One type is finite optical structural design, in which light passing through the objective lens is directed at the intermediate image plane (located in the front focal plane of the eyepiece) and converges at that point. The finite structure is an integrated design, with a compact structure, and it is a kind of economical microscope. Another type is infinite optical structural design, in which the light between the tube lens after passing the objective lens becomes "parallel light". Within this distance, various kinds of optical components necessary such as beam splitters or optical filters call be added, and at the same time, this kind of design has better imaging results. As the design is modular, it is also called modular microscope. The modular structure facilitates the addition of different imaging and lighting accessories in the middle of the system as required. The main components of infinite and finite, especially objective lens, are usually not interchangeable for use, and even if they can be imaged, the image quality will also have some defects. The separative two-objective lens structure of the dual-light path of stereo microscope (SZ/FS microscope) is also known as Greenough. Parallel optical microscope uses a parallel structure (PZ microscope), which is different from the separative two-object lens structure, and because its objective lens is one and the same, it is therefore also known as the CMO common main objective. |
System Optical MagnificationClose Λ
| The magnification of the objective lens refers to the lateral magnification, it is the ratio of the image to the real size after the original image is magnified by the instrument. This multiple refers to the length or width of the magnified object. System optical magnification is the product of the eyepiece and the objective lens (objective lens zoom set) of the optical imaging part within the system. Optical magnification = eyepiece multiple X objective lens/objective lens set The maximum optical magnification of the microscope depends on the wavelength of the light to which the object is illuminated. The size of the object that can be observed must be greater than the wavelength of the light. Otherwise, the light cannot be reflected or transmitted, or recognized by the human eye. The shortest wavelength of ultraviolet light is 0.2 microns, so the resolution of the optical microscope in the visible range does not exceed 0.2 microns, or 200 nanometers. This size is converted to the magnification of the microscope, and it is the optical magnification of 2000X. Usually, the compound microscope can achieve 100X objective lens, the eyepiece is 20X, and the magnification can reach 2000X. If it is bigger, it will be called "invalid magnification", that is, the image is large, but the resolution is no longer increased, and no more details and information can be seen. |
Trinocular Optical MagnificationClose Λ
| When the instrument is conducting electronic image magnification and observation through a camera or the like, the optically magnified portion may not be the optical path that passes through the "eyepiece-objective lens" of the instrument, at this time, the calculation method of the magnification is related to the third-party photo eyepiece passed. The trinocular optical magnification is equal to the multiplier product of objective lens (objective lens set) and the photo eyepiece Trinocular optical magnification = objective lens X photo eyepiece |
Total MagnificationClose Λ
| Total magnification is the magnification of the observed object finally obtained by the instrument. This magnification is often the product of the optical magnification and the electronic magnification. When it is only optically magnified, the total magnification will be the optical magnification. Total magnification = optical magnification X electronic magnification Total magnification = (objective X photo eyepiece) X (display size / camera sensor target ) |
System Field of ViewClose Λ
| Field of View, is also called FOV. The field of view, or FOV, refers to the size of the object plane (i.e., the plane of the point of the observed object perpendicular to the optical axis), or of its conjugate plane (i.e., object to primary image distance), represented by a line value. System field of view is the size of the actual diameter of the image of the terminal display device of the instrument, such as the size of the image in the eyepiece or in the display. Field of view number refers to the diameter of the field diaphragm of the objective lens, or the diameter of the image plane formed by the field diaphragm. Field of view number of objective lens = field of view number of eyepiece / (objective magnification / mechanical tube length) Large field of view makes it easy to observe the full view and more range of the observed object, but the field of view (FOV) is inversely proportional to the magnification and inversely proportional to the resolution, that is, the larger the field of view, the smaller the magnification, and also the lower the resolution of the object to be observed. There are usually two ways to increase the field of view, one is to replace with an objective lens of a smaller multiple, or to replace with an eyepiece of a smaller multiple. |
SiedentopfClose Λ
| For siedentopf eyetube, when changing the interpupillary distance, it requires two hands pushing or pulling the two eyetubes left and right simultaneously, and the two eyepiece tubes or eyetubes will change their position at the same time. |
Eye Tube AngleClose Λ
| Usually the Microscope Eyetube is 45°, some is 30°, Tiltable Eyetube Angle design of a microscope is also known as the ergonomics microscope. 0-30° or 0-45° is an ergonomic design. When the mechanical tube length / focal length of the tube of the microscope is relatively big, the microscope is relatively high, and the user's height or the seat of the work desk is not suitable, long-term use of microscope may cause sitting discomfort. Eyepiece tube with variable angle can freely adjust the angle without lowering the head. Especially when it is close to 0 degree and the human eye is close to horizontal viewing, long-time or long-term use can avoid fatigue damage to the cervical vertebra. |
Erect/Inverted ImageClose Λ
| After imaging through a set of objective lenses, the object observed and the image seen by the human eye is inverted. When the observed object is manipulated, move the specimen or object, the image will move in the opposite direction in the field of view. Most of the biological microscopes are reversed-phase designs. When needing to operate works with accurate direction, it is necessary to design it into a forward microscope. Generally stereo microscopes and metallurgical microscopes are all of erect image design. When observing through the camera and display, the erect and inverted image can be changed by the orientation of the camera. |
360° Degree RotatableClose Λ
| The eyepiece of the microscope can have different viewing or observing directions. When the position of the microscope is uncomfortable, the direction of the eyepiece tube of the microscope can be adjusted, to facilitate observation and operation. Placement method of different viewing angles of the microscope: General direction: the support column is behind the object to be observed Reverse direction: the support column is in front of the object to be observed Lateral direction: the support column is on the side of the object to be observed Rotating eyepiece tube, different microscopes may have different methods, for some, the direction is confirmed when installing the eyepiece tube of the microscope, for some, by rotating the body of the microscope, and for some, by rotating the support member on the support or holder of the microscope. |
Interpupillary AdjustmentClose Λ
| The distance between the two pupils of the human eye is different. When the image of exit pupil of the two eyepieces of the microscope are not aligned with the entry pupil of the eye, the two eyes will see different images, which can cause discomfort. Adjust the distance between the two eyepieces, to accommodate or adapt to the pupil distance of the observer's eyes. The adjustment range is generally between 55-75mm. |
Eye Tube Diopter AdjustableClose Λ
| For most people, their two eyes, the left and the right, have different vision; for the eyepiece tube, the eyepoint height of the eyepiece can be adjusted to compensate for the difference in vision between the two eyes, so that the imaging in the two eyes is clear and consistent. The range of adjustment of the eyepiece tube is generally diopter plus or minus 5 degrees, and the maximum differential value between the two eyepieces can reach 10 degrees. Monocular adjustable and binocular adjustable: some microscopes have one eyepiece tube adjustable, and some have two eyepiece tubes adjustable. First, adjust one eyepiece tube to the 0 degree position, adjust the microscope focusing knob, and find the clear image of this eyepiece (when the monocular adjustable is used, first adjust the focusing knob to make this eyepiece image clear), then adjust the image of another eyepiece tube (do not adjust the focusing knob again at this time), repeatedly adjust to find the clear position, then the two images are clear at the same time. For this particular user, do not adjust this device anymore in the future. As some microscopes do not have the vision adjustment mechanism for the eyepiece tube, the vision of the two eyes are adjusted through the eyepiece adjustable. |
Image Port Switch ModeClose Λ
| The third eyepiece splitting in the trinocular microscope is to borrow one of the two sets of eyepiece optical paths as the photographic light path. The beam split prism or beam splitter can reflect part of the image light to the eyepiece, and part passes through to the third eyepiece photographic light path, such a trinocular microscope is called trinocular simultaneous imaging microscope, or true-trinocular. The beam split prism or beam splitter of the trinocular simultaneous imaging microscope or true-trinocular often has different splitting modes, such as 20/80 and 50/50, etc. Usually, the former is the luminous flux ratio of the eyepiece optical path, and the latter is the luminous flux ratio of the photographic optical path. The advantage of true-trinocular is that, the real three optical paths can be imaged at the same time, and are not affected by the simultaneous use of the eyepiece observation and the photographic optical path (display). The disadvantage is that, because of the reason of the splitting, the image light of the photography is only a part. In theory, the image effect will be affected, and the effect is more obvious in the binocular eyepiece observation. If viewed closely, one will find that the eyepiece of the light path is relatively dark. However, in the current optical design and materials, the impact on the actual work is not very big, especially in the observation of low magnification objective lens, it has basically no effect at all, and therefore used by many people. |
Adjustable EyepieceClose Λ
| The adjustable eyepiece is between the lens of the eyepiece and the focal plane, with distance adjustable device. For most people, their two eyes, the left and the right, have different vision. For adjustable eyepieces, the eyepoint height of the eyepiece can be adjusted to compensate for the difference in vision between the two eyes, making the image in the two eyes clear and consistent. The range of adjustment of the general eyepiece is that the diopter is plus or minus 5 degrees, and the maximum difference between the two eyepieces can reach 10 degrees. Before use, it is generally necessary to adjust both eyepieces to the initial position where the scale is displayed as 0, which is used as a baseline to facilitate up and down adjustment. The reticle position of the eyepiece is generally 10mm below the fixed position of the eyepiece tube. Because the vision of each person is different, some people may not be able to see the reticle clearly. For adjustable eyepiece, the height of the reticle position can be adjusted to make the reticle and the observed object clear at the same time, this is the advantage of adjustable eyepiece that mounts the diopter adjustment on the eyepiece tube compared with non-adjustable eyepiece. When non-adjustable eyepiece is equipped with a reticle, if the diopter is adjusted, the reticle will rotate accordingly, thereby affecting the position of the measurement. For adjustable eyepiece, when its diopter is adjusted, its reticle does not rotate. |
Eyepiece Optical MagnificationClose Λ
| Eyepiece optical magnification is the visual magnification of the virtual image after initial imaging through the eyepiece. When the human eye observes through the eyepiece, the ratio of the tangent of the angle of view of the image and the tangent of the angle of view of the human eye when viewing or observing the object directly at the reference viewing distance is usually calculated according to 250 mm/focal length of eyepiece. The standard configuration of a general microscope is a 10X eyepiece. Usually, the magnification of the eyepiece of compound microscope is 5X, 8X, 10X, 12.5X, 16X, 20X. As stereo microscope has a low total magnification, its eyepiece magnification generally does not use 5X, but can achieve 25X, 30X and other much bigger magnification. |
Eyepiece Field of ViewClose Λ
| The eyepiece field of view is the diameter of the field diaphragm of the eyepiece, or the diameter of the image plane of the field diaphragm imaged by the field diaphragm. The diameter of a large field of view can increase the viewing range, and see more detail in the field of view. However, if the field of view is too large, the spherical aberration and distortion around the eyepiece will increase, and the stray light around the field of view will affect the imaging effect. |
Eyepoint TypeClose Λ
| Eye point refers to the axial distance between the upper end of the metal frame of the eyepiece and the exit of pupil. The exit of pupil distance of high eyepoint eyepiece is farther than that of the eye lens of the ordinary eyepiece. When this distance is greater than or equal to 18mm, it is a high eyepoint eyepiece. When observing, one does not need to be too close to the eyepiece lens, making it comfort to observe, and it can also be viewed with glasses. Generally, there is a glasses logo on the eyepiece, indicating that it is a high eyepoint eyepiece. |
Nosepiece with SlotClose Λ
| The nosepiece has a slot for mounting polarizers, filters and other devices. |
Illumination BaseClose Λ
| Illumination base is a modular light source component, suitable for microscope stand base that has no light source of itself, and it is usually dedicated components supporting some stands. Illumination base typically includes at least one bottom lighting, and there are also illumination base that includes the circuit portion of the upper light source. |
Coaxial Coarse/Fine FocusClose Λ
| Focus mechanism, the coarse / fine focus knobs are in a coaxial center position, they are connected together by a gear reduction mechanism, which can be coarse/ fine focus adjusted at any time during the entire stroke. Generally, the coarse focus diameter is relatively big, which is inside close to the body of the microscope, and the fine focus diameter is relatively small, which is outside of the body of the microscope. Coarse focus adjustment is used to quickly move to find the image, and the fine focus adjustment is used to finely adjust the clarity of the image. Generally, the minimum read value of the fine focus adjustment can be accurate to 1 micron, and single circle can reach a stroke of 0.1 mm. Mechanical fine focus plays a very important role in the accuracy of the microscope resolution. If the fine focus accuracy is not enough, or cannot be stabilized at the sharpest focusing position, the image will be out of focus and become blurred. The tightness of coarse focus is generally adjustable. Generally, on one side of the knob (usually on the right side), there is a textured knob on the inside of the coarse knob, which is tightened if rotated clockwise; and loosened if rotated counterclockwise. In the process of focusing, direct focusing should not be on the objective of high magnification; instead, find the object of low magnification first, and gradually adjust to high magnification. Usually, the coarse focus knob is rotated first, and when the objective lens is gradually lowered or the platform is gradually rising, find the object, and then adjust with the fine focus, until the object image in the field of view is clear. Generally, when changing from low magnification to high magnification objective, one only need to slightly adjust the fine focus knob to make the object image clear. During the process, the distance between the objective and the specimen should be observed from the side, to understand the critical value of the object distance between the lens and the specimen. When using a high magnification objective, since the distance between the objective and the specimen is very close, after the image is found, the coarse focus knob cannot generally be used, and the fine focus knob can only be used to avoid excessive distance of movement, damaging the objective and the slide or specimen. By using the characteristics of the fine focus, the height or thickness of the observed object can be roughly measured under the microscope, such as measuring the thickness of the cell or tissue, the thickness of the cover glass, and the thickness of small objects that cannot be measured by various conventional measuring instruments. Method of measurement: place the object to be measured at the center of the field of view of the stage. After the image is clearly focused, try to use the highest magnification objective as much as possible, and align the adapter of the top feature point of the object to be measured. After adjusting clear, record the position of scale of the fine focus knob. Then, move the objective down to the adapter of the lowest feature point of the object to be measured, and record the position of scale of the fine focus knob. Then, according to the above fine focus, record the number of rounds of movement, and based on the parameters of conversion of each round into stroke (see the microscope fine focus knob parameters), the number of rounds is converted into the total stroke, which is the height of the object to be measured. If it is repeated a few times for average, a more accurate measurement can be obtained. |
