Finite. Total Magnification: 40-400X. 10X Eyepiece;10X Reticle Eyepiece. 4X 10X 40X Plan Achromatic Polarizing Objective. Standard Coupler: 0.5X. Eye Tube Angle: 30°. Eyepiece Field of View: Dia. 18mm. Illumination Type: Halogen Transmitted Light. Input Voltage: AC 90-240V 50/60Hz.
Environmental , Asbestos, Industrial , Glass Industry, Materials Science, Metallurgy , Archaeology, Petrology
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.
|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.
Mechanical Tube LengthClose Λ
|For objective lens design of finite microscope, its mechanical tube length is the distance from the objective nosepiece shoulder of the objective lens to the eyepiece seat in the tubes, that is, the eyepiece shoulder.|
There are two standards in the traditional microscope structure, namely, DIN and JIS. DIN (Deutsches Institute fur Normung) is a popular international standard for microscopes, using 195mm standard conjugate distance (also known as object to primary image distance, 36mm objective lens parfocal distance, and 146.5mm optical tube length.
JIS (Japanese Industrial Standard) is a standard adopted by some Japanese manufacturers, using 160mm standard conjugate distance (also known as object to primary image distance), 45mm objective lens parfocal distance), and 150mm optical tube length.
Using the same microscope standard design, the objective lenses can be used interchangeably.
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.
System Working DistanceClose Λ
|Working distance, also referred to as WD, is usually the vertical distance from the foremost surface end of the objective lens of the microscope to the surface of the observed object.|
When the working distance or WD is large, the space between the objective lens and the object to be observed is also large, which can facilitate operation and the use of corresponding lighting conditions.
In general, system working distance is the working distance of the objective lens. When some other equipment, such as a light source etc., is used below the objective lens, the working distance (i.e., space) will become smaller.
Working distance or WD is related to the design of the working distance of the objective lens. Generally speaking, the bigger the magnification of the objective lens, the smaller the working distance. Conversely, the smaller the magnification of the objective lens, the greater the working distance.
When it is necessary to change the working distance requirement, it can be realized by changing the magnification of the objective lens.
|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.
Reticle EyepieceClose Λ
|Reticle eyepiece. The eyepiece focal length (10mm below the eyepiece mounting surface eyepiece shoulder) of the reticle eyepiece is equipped with a reticle for measuring and positioning the object to be observed.|
For one microscope, a reticle can be installed only on one eyepiece, and it requires that the two eyepieces should be completely identical. If two are installed, it is generally very difficult to make the two reticles of both the left and the right eyepiece completely overlap, which may cause eye discomfort.
The reticle eyepieces are generally used on 10X and 20X eyepieces.
The mounting dimension of the reticle refers to the size of the inner diameter of the lower end tube of the eyepiece. It requires that the eyepiece that can be equipped with a reticle needs a preset thread and a pressing ring. The reticle is facing up (in the direction of the eyepiece lens), placed flat on the reticle mounting surface of the eyepiece, and screwed in with a pressure ring, and press tight. Ordinary users can also install the reticle on their own as needed.
The reticle is generally made of glass material, and the etched printed surface is the front side. It is mounted on the end close to the eye, which is the position of the eyepiece image plane; when avoiding the use of different reticle, the focal length is different due to the different thickness of the glass, which makes the scribe line of the reticle fall on the unclear image plane position.
The reticle is placed under the eyepiece. When measuring the object, the reticle and the object to be measured are also magnified by the eyepiece, so the actual length of the reading has no relation at all with the magnification of the eyepiece.
When the reticle reads the length value in the eyepiece of the microscope, because the length of the image to be measured passes through the objective lens and reaches the image plane position of the reticle, the length read is actually the length magnified by the objective lens. The real numerical value should be the length of the reading, divided by the numerical value of magnification of the objective lens. If it is the zoom microscope body with also magnification, it should also be divided by the magnification (objective lens X zoom).
In this measurement method, the error mainly lies in that the magnification of the objective lens is not calibrated, and the magnification error of ordinary microscope objective lens can reach +-5%. Therefore, for accurate measurement, it should be used after calibration with the objective micrometer. For the calibration method, please refer to the introduction of “Reticle”.
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.
Objective Optical MagnificationClose Λ
|The finite objective is the lateral magnification of the primary image formed by the objective at a prescribed distance.|
Infinite objective is the lateral magnification of the real image produced by the combination of the objective and the tube lens.
Infinite objective magnification = tube lens focal length (mm) / objective focal length (mm)
Lateral magnification of the image, that is, the ratio of the size of the image to the size of the object.
The larger the magnification of the objective, the higher the resolution, the smaller the corresponding field of view, and the shorter the working distance.
Objective TypeClose Λ
|In the case of polychromatic light imaging, the aberration caused by the light of different wavelengths becomes chromatic aberration. Achromatic aberration is to correct the axial chromatic aberration to the two line spectra (C line, F line); apochromatic aberration is to correct the three line spectra (C line, D line, F line).|
The objective is designed according to the achromaticity and the flatness of the field of view. It can be divided into the following categories.
Achromatic objective: achromatic objective has corrected the chromatic aberration, spherical aberration, and comatic aberration. The chromatic portion of the achromatic objective has corrected only red and green, so when using achromatic objective, yellow-green filters are often used to reduce aberrations. The aberration of the achromatic objective in the center of the field of view is basically corrected, and as its structure is simple, the cost is low, it is commonly used in a microscope.
Semi-plan achromatic objective: in addition to meeting the requirements of achromatic objective, the curvature of field and astigmatism of the objective should also be properly corrected.
Plan achromatic objective: in addition to meeting the requirements of achromatic objectives, the curvature of field and astigmatism of the objective should also be well corrected. The plan objective provides a very good correction of the image plane curvature in the field of view of the objective, making the entire field of view smooth and easy to observe, especially in measurement it has achieved a more accurate effect.
Plan semi-apochromatic objective: in addition to meeting the requirements of plan achromatic objective, it is necessary to well correct the secondary spectrum of the objective (the axial chromatic aberration of the C line and the F line).
Plan apochromatic objective: in addition to meeting the requirements of plan achromatic objective, it is necessary to very well correct the tertiary spectrum of the objective (the axial chromatic aberration of the C line, the D line and the F line) and spherochromatic aberration. The apochromatic aberration has corrected the chromatic aberration in the range of red, green and purple (basically the entire visible light), and there is basically no limitation on the imaging effect of the light source. Generally, the apochromatic aberration is used in a high magnification objective.
Objective for Mechanical Tube LengthClose Λ
|Objective for mechanical tube length is a design parameter of the mechanical tube length of the microscope that the objective is suitable for.|
Objective Working DistanceClose Λ
|The objective working distance is the vertical distance from the foremost surface end of the objective of the microscope to the object surface to be observed.|
Generally, the greater the magnification, the higher the resolution of the objective, and the smaller the working distance, the smaller the field of view. Conversely, the smaller the magnification, the lower the resolution of the objective, and the greater the working distance, and greater the field of view.
High-magnification objectives (such as 80X and 100X objectives) have a very short working distance. Be very careful when focusing for observation. Generally, it is after the objective is in position, the axial limit protection is locked, then the objective is moved away from the direction of the observed object.
The relatively greater working distance leaves a relatively large space between the objective and the object to be observed. It is suitable for under microscope operation, and it is also easier to use more illumination methods. The defect is that it may reduce the numerical aperture of the objective, thereby reducing the resolution.
Numerical Aperture (N.A.)Close Λ
|Numerical aperture, N.A. for short, is the product of the sinusoidal function value of the opening or solid angle of the beam reflected or refracted from the object into the mouth of the objective and the refractive index of the medium between the front lens of the objective and the object.|
Simply speaking, it is the magnitude of the luminous flux that can be brought in to the mouth of the objective adapter, the closer the objective to the specimen for observation, the greater the solid angle of the beam entering the mouth of the objective adapter, the greater the N.A. value, and the higher the resolution of the objective.
When the mouth of the objective adapter is unchanged and the working distance between the objective and the specimen is constant, the refractive index of the medium will be of certain meaning. For example, the refractive index of air is 1, water is 1.33, and cedar oil is 1.515, therefore, when using an aqueous medium or cedar oil, a greater N.A. value can be obtained, thereby improving the resolution of the objective.
N.A. = refractive index of the medium X sin solid angle of the beam of the object entering the front lens frame of the objective/ 2
Numerical aperture of the objective. Usually, there is a calculation method for the magnification of the microscope. That is, the magnification of the microscope cannot exceed 1000X of the objective. For example, the numerical aperture of a 100X objective is 1.25, when using a 10X eyepiece, the total magnification is 1000X, far below 1.25 X 1000 = 1250X, then the image seen in the eyepiece is relatively clear; if a 20X eyepiece is used, the total magnification will reach 2000X, much higher than 1250X, then eventhoughthe image actually seen by the 20X eyepiece is relatively large, the effect will be relatively poor.
Objective Cover Glass ThicknessClose Λ
|The thickness of the cover glass affects the parfocal distance of the objective. Usually, in the design of the focal length of the objective,the thickness of the cover glass should be considered, and the standard is 0.17mm.|
Objective Immersion MediaClose Λ
|The use of different media between the objective and the object to be observed is to change and improve the resolution. For example, the refractive index of air is 1, water is 1.33, and cedar oil is 1.515. Therefore, when using an aqueous medium or cedar oil, a greater N.A. value can be obtained, thereby increasing the resolution of the objective.|
Air medium is called dry objective, where oil is used as medium iscalled oil immersion objective, and water medium is called water immersion objective.
However, because of the working distance of the objective, when the working distance of the objective is too long, the use of liquid medium will be relatively more difficult, and it is generally used only on high magnification objective having a shorter working distance, such as objectives of 60X, 80X and 100X.
When using oil immersion objective, first add a drop of cedar oil (objective oil) on the cover glass, then adjust the focus (fine adjustment) knob, and carefully observe it from under the side of the objective of the microscope, until the oil immersion objective is immersed in the cedar oil and close to the cover glass of the specimen, then use the eyepiece to observe, and use the fine focus knob to lift the tube until the clear imageof the specimen is clearly seen.
The cedar oil should be added in an appropriate amount. After the oil immersion objective is used, it is necessary to use a piece of lens wiping tissue to dip xylene to wipe off the cedar oil, and then wipe dry the lens thoroughly with a lens wiping tissue.
Objective Screw ThreadClose Λ
|For microscopes of different manufacturers and different models, the thread size of their objectives may also be different. |
In general, the objective threads are available in two standard sizes, allowing similar objectives between different manufacturers to be used interchangeably.
One is the British system: RMS type objective thread: 4/5in X 1/36in,
One is metric: M25 X 0.75mm thread.
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.
Focusing Knob Tightness AdjustableClose Λ
|Different microscope bodies, different human operations, and different requirements for observation and operation, all require adjustment of the pre-tightening force of the stand that support microscope body.|
Facing the stand just right, use both hands to reverse the force to adjust the tightness. (face the knob of one side just right, clockwise is to tighten, counterclockwise is to loosen)
In general, after long-time use, the knob will be loose, and adjustment is necessary.
Kohler IlluminationClose Λ
|Kohler illumination: is a secondary imaging illumination that overcomes the shortcoming of direct illumination of critical illumination. After the filament of the light source passes through the condenser and the variable field diaphragm, the filament image falls for the first time in the condenser aperture diaphragm, the condenser forms a second image at the back focus plane position there, so that there is no filament image at the plane of the object to be observed, and the illumination becomes uniform.|
During observation, by changing the size of the condenser aperture diaphragm, the light source fills in the entrance pupil of the objective lens, and the numerical aperture of the condenser is matched with the numerical aperture of the objective lens. At the same time, the condenser images the field diaphragm at the plane of the observed object, and the illumination range is controlled by the size of the field diaphragm. Since the thermal focus of Kohler illumination is not at the plane of the object to be observed, the object to be observed will not be damaged even if it is irradiated for a long time.
Abbe Condenser Close Λ
|Abbe condenser is a kind of bright field condenser, a condenser that can only finitely correct the spherical aberration, but not the chromatic aberration. When the numerical aperture of its objectives is higher than 0.6, Abbe condenser will show chromatic aberration and spherical aberration.|
Color FilterClose Λ
|Color filter is a type of filter that allows light of only a certain wavelength and color range to pass, while light of other wavelengths is intercepted. Color filter is made of colored glass, and it has various bandwidths and color for selection.|
Both artificial light source (lamp light) and natural light (daylight) are all full-color light, including seven colors, namely, red, orange, yellow, green, blue, indigo and purple. As the microscope illumination, different types of light sources have different color temperatures and brightness. In order to adjust the color of the light source, it is necessary to install a filtering device at the light exit port of the light source, so that the spectrum of a certain wavelength band is transmitted or blocked. Color filter generally can only be added to the illumination path to change the color of the illumination source and improve the contrast of the image, but generally it is not installed in the imaging path system, which affect the image quality.
There are many types of color filters. In addition to the color requirements, color filters of different colors also contribute to the imaging quality. Color filters using the same color will brighten the color of the image.
Of the traditional daylight filter, there are relatively more red and yellow light in the lamp light, the resolution is not high, and the observation is not comfortable. The use of daylight filter can absorb the color between yellow to red spectrum emitted by the light source, thus the color temperature becomes much closer to daylight, making microscope observation more comfortable, and it is one of the most used microscope color filters.
Daylight blue filter can get close to the daylight spectrum, obtain more short-wave illumination, and improve the resolution of the objective lens. For example, using blue color filter (λ=0.44 microns) can improve the resolution by 25% than green color filter (λ=0.55 microns). Therefore, blue color filter can improve the resolution, and improve the image effect observed under the microscope. However, the human eye is sensitive to green light with a wavelength of about 0.55 microns. When using blue color filters for photomicrography, it is often not easy to focus on the projection screen.
Yellow and green filters: both yellow and green filters can increase the contrast (i.e. contrast ratio) of details of the specimen. As far as the achromatic objective lens is concerned, the aberrations in the yellow and green bands are better corrected. Therefore, when yellow and green color filters are used, only yellow and green light passes, and the aberration will be reduced, thereby improving the imaging quality. For semi-apochromatic and apochromat objectives, the focus of visible light is concentrated. In principle, any color filter can be used, but if yellow and green filters are used, the color will make the human eye feel comfortable and soft.
Red filter. Red has the longest wavelength and the lowest resolution in visible light. However, red light image can filter and eliminate the variegated background in the image. Therefore, so it has a very good effect for some applications that do not require color features for identification, and the edges and contours of the image are also the clearest, which is more accurate for measurement.
Medium gray filters, also known as neural density filters, or ND for short, can uniformly reduce visible light. It is suitable for photomicrography and connection to computer monitors for observation. ND can be used for exposure control and good light absorption, and reduce the light intensity while not changing the color temperature of the microscope light source.
|After unpacking, carefully inspect the various random accessories and parts in the package to avoid omissions. In order to save space and ensure safety of components, some components will be placed outside the inner packaging box, so be careful of their inspection.|
For special packaging, it is generally after opening the box, all packaging boxes, protective foam, plastic bags should be kept for a period of time. If there is a problem during the return period, you can return or exchange the original. After the return period (usually 10-30 days, according to the manufacturer’s Instruction of Terms of Service), these packaging boxes may be disposed of if there is no problem.
|Microscope Optical Data Sheet|
|P/N||Objective||Objective Working Distance||Eyepiece|
|PL05072231 (10X Dia. 18mm)||BM05072212 (10X Dia. 18mm)|
|Magnification||Field of View(mm)||Magnification||Field of View(mm)|
|1. Magnification=Objective Optical Magnification * Body Magnification * Eyepiece Optical Magnification|
|2. Field of View=Eyepiece Field of View /（Objective Optical Magnification*Body Magnification）|
|3. The Darker background items are Standard items, the white background items are optional items.|
|Desiccant Bag||1 Bag|
|Allen Key||M2.5 1pc|
|Product Instructions/Operation Manual||1pc|
|Packaging Type||Carton Packaging|
|Packaging Material||Corrugated Carton|
|Packaging Dimensions(1)||46x25x55cm (18.110x9.843x21.654″)|
|Inner Packing Material||Plastic Bag|
|Ancillary Packaging Materials||Expanded Polystyrene|
|Gross Weight||9.59kg (21.14lbs)|
|Minimum Packaging Quantity||1pc|
|Transportation Carton||Carton Packaging|
|Transportation Carton Material||Corrugated Carton|
|Transportation Carton Dimensions(1)||46x25x55cm (18.110x9.843x21.654″)|
|Total Gross Weight of Transportation(kilogram)||9.59|
|Total Gross Weight of Transportation(pound)||21.14|