The microscope is not just a magnifying device, a rather complicated optical device. It is a device that will allow you to experience the exciting and fascinating microcosm.
Molecules, atoms, elementary particles – all these, at first glance, insignificant elements of our vast world, actually are the Foundation of all things, and to observe the processes associated with their “livelihoods”, a very interesting exercise.
However, in order to purchase a quality appliance, you need to have at least a superficial representation of its functional features, structure, and properties.
Next, we’ll talk about those features and characteristics which are decisive in the selection of the microscope.
Currently, there are several types of microscopes:
The structure of device entry-level includes:
They do not have full capacitor. Microscopes for novice researchers can give increase to about 200×.
Educational microscopesusually buy for children of school age. Their design is the following:
These microscopes guarantee increase to 650×.
Instrumental stereoscopic microscope, stereo microscope, designed for observing relatively large objects:
The microscope provides magnification up to 100× and with a separate optical system creates a three-dimensional image for each eye.
Device biological microscope is:
This model will increase 1000-1500×. It is worth noting that the device with binocular nozzle projects a flat image.
The use of the electron microscope, mainly takes place in the laboratory because they are in many respects superior to optical devices.
But electronic devices are unlikely to be useful in a home environment, because in order to understand their design and principle of operation, it is necessary to be seven spans in a forehead. Therefore, to burden the ordinary reader a very daunting information makes no sense, but the person who really could use a microscope, for sure no need to comment about it.
Digital microscope is the most functional character of the article, and the cost, naturally, is appropriate.
This arrangement allows you to send the resulting image to the monitor of the computer and to connect various information devices such as a camcorder or camera. You can save images on digital media and even correct.
The advantage of digital microscopes in front of electronic devices is their compactness and low energy consumption.
The microscope consists of a tube that holds the eyepiece and lens. The tube is fixed on the rack, which is attached to the stage and condenser with lighting fixture. As the illuminator acts as a built-in light or a mirror. With the help of an electric lighting device, the image acquires a greater brightness than when using a mirrored illuminator.
The capacitor is for adjustment of illumination. In the most primitive models of the microscope condenser is missing or it is equipped with a single lens with wheel aperture. For comfortable use we strongly recommend you to get a device with a movable subject table.
The lens is fixed in the turret of a microscope, so it is possible install 3-4 lenses simultaneously and very quickly change the magnification. The entry-level microscopes equipped with only one lens. Adjusting the gain of such a device is possible by replacing eyepieces.
There are three types of lenses:
The use of immersion allows to significantly increase the resolution of the lens. As a rule, by immersion of the lens it is possible to increase from 40 or more times. Raw material for oil-immersion is a cedar or a special synthetic oil, but for water – distilled water.
Immersion lenses have the markings:
Lenses with a water immersion include the following indexing:
In the case of a dry lens marking on the lens is missing.
The type of optical correction lenses divided into:
Chromatic difference of magnification and curvature of field of the lenses-achromats are established, therefore, the edges of the field of view of the image will smear.
Apochromatic fixed exclusively chromatic aberration, and chromatic difference of magnification and curvature of field is not. In the marking code specified lens optical correction:
Planachromatic fully corrected the curvature of field, chromatic aberration and difference of magnification. This lens is used to produce small gains, because it generates a sharp crisp image throughout the field. Marked code optical correction:
Planapochromat have fully corrected for chromatic aberrations. Also they are characterized by the flat field and corrected chromatic difference of magnification. In the marking of such lenses specified the following code optical correction:
Options optical correction lenses-semiplane are between Framatome and planachromatic. In addition, the curvature of the field is reduced. In the marking code configured optical correction:
If you are going to observe through the microscope objects with relatively large dimensions, in this case it’s better to get a lens with a small increase in code correction:
Similar lens ensures a sharp image across the entire field of view. If you want to take pictures through a microscope, it is worth looking at the lens with full correction of chromatic aberration, correction of field and chromatic difference of magnification.
Looking at the lens, you’ll clearly see there magnification lens, and a fraction numerical aperture NA, which shows the limit of useful magnification, and also indicates the resolution of the lens. It happens that on the lens indicate the length of the tube of the microscope and the thickness of the cover glass with which the lens will “cooperate” with regular increase.
On the magnification of the microscope is affected by the characteristics of the objective lens and eyepiece, it is measured in crats (×). To calculate the magnification with the following formula: increase of the lens multiplied with the rate of increase of the eyepiece.
The magnification of the microscope depends on the magnification of the lens. The magnification of the lens, in turn, are divided into:
The magnification of the microscope may reach the level of 2000×.
Magnification of eyepiece microscopes for research is 10× and the magnification of their lenses – 4-100×. Also the magnification of the microscope depends on its device. For a child at the time will be instrument with magnification of 200×, for school-age children and beginners, it is best device with magnification 400×, and for the experienced user – with an increase of 1,500-2,000×.
In addition to the increase of the microscope there is another, not less important feature, responsible for the quality and sharpness of the picture. This parameter is the resolution.
This parameter is determined by the condenser and the lens, and calculate it as follows: the wavelength of light divided by two numerical apertures. The higher the number of aperture of the lens, the higher, in fact, the resolution of the microscope.
High resolution – the minimum distance at which all points can be seen in focus. Limit the resolution of optical devices is equal to 0.2 µm. There is also a useful magnification of the microscope at which the object can be observed under the maximum allowable angle for the human eye. The maximum useful magnification depends on the numerical aperture of the lens, which is increased 500-1000 times.
Bezymianny numerical aperture of the lens is 1.0, thus limiting useful magnification is 1000×. Numerical aperture immersion lens is 1.25, so the maximum of this index is equal to 1250×. Both low and higher magnification of the microscope is considered to be ineffective because it generates a fuzzy, unclear and blurry image.
Eyepieces come in 3 types:
Monocular head, as you can tell from the title, are equipped with a single eyepiece in which you will be able to immerse themselves in only one eye. Binocular – its structure vaguely resemble a pair of binoculars, they will let you in the study of the microcosm to arm themselves with two eyes. Trinocular head – universal, it is a hybrid binocular and monocular eyepieces.
School microscopes equipped with conventional eyepieces of Huygens system, the frame lists only their increase. These eyepieces have a modest field of view and are not provided for correction of the chromatism. Index To denotes for compensating eyepieces. These eyepieces will be useful for microphotography using digital devices. Release several types of compensating eyepieces, including wide-angle and marked WF.
Eyepieces with a scale to be useful for accurate measurement of the dimension indices of the object. These eyepieces is equipped with a grid that allows to measure the area of the observed object.
Eyepiece with pointer, which is a special removable needle, comes with educational microscopes. Using this needle you can specify the specific location of the object.
Choosing a microscope should focus on its ergonomics: the eyes should not strain even during long observation. Also, rate the clarity, saturation and contrast of the image. If you are looking to buy binocular microscope, check the distance between the pupils.
It is wise to give preference to a movable subject table, because it is adjusted by means of micrometer screws and allows you to move the object without the use of hands. In a situation with a static table you will be forced to move the object manually.
If you get a device provided by the option of connecting to the camera, in addition to it you must make a special photoadapter, set of eyepieces and slides. Pay attention to the quality of each element of the device, in particular, lenses and eyepieces.
Operation and maintenance of the microscope should be comfortable, and also the device shall be subject to detailed setup. When choosing a microscope make sure that the mount tube to the rack is carried out appropriately. When purchasing a microscope, it is better to stay on the device with electric lighting, because this method is much more effective than the use of mirrored lights.
The binocular device is more preferable option. He ensures the comfort when observing an object, because it allows to consider the object with both eyes. It is advisable to buy a microscope with a turret, as it is equipped with several lenses simultaneously, so you can easily change the magnification of the observed object.
There are General rules of safety in the operation microscope of different brands and designs, as well as a certain technique to work, setting up and care of these devices. To ensure that the device has served you in good stead, it must be preserved as the Apple of his eye.
To protect the microscope from dust can keep it in a plastic bag or under a cover glass. If you are the owner of a microscope, I advise you to hide it in a closet or in a drawer. Protect the device from mechanical damages, during transportation it is advisable to hold the microscope stand with one hand and the base of the second.
Regularly check the fixing of the lenses in the nest turret of the device. Ensure lens lenses, eyepieces and condensers do not come into contact with a variety of reagents. It is not necessary to remove the binocular head and to come into contact with any surface of the fingers, especially with an a lens, so as not to leave a greasy residue.
Do not remove the metal lens body and disassemble it. Lenses should be kept in a lowered position during use. Make sure that they never touched the subject table. Before or after use of the microscope in the imperative to wipe the lenses, eyepieces and condensers.
Twice a year you need to clean and lubricate metal components of the device silicone grease. The microscope must be set exclusively on a solid surface without defects to avoid his fall. Keep the device at a safe distance from the water in a cool, dry place at a temperature of about +10◦C, to protect it from zaplesnevelye and corrosion.
Sometimes check lens for the forming of dust layers. If the lens accumulates dust, it is this “disease” is removed with a soft brush, previously soaked in ether. In any case it is impossible to put pressure on the lens when cleaning, because there’s a risk to leave a scratch, even if you use the special cloths designed for this purpose. If contaminated, the lenses need to be wiped with a clean linen or cotton cloth, soaking it in ether or benzene.
To wipe off the oil with lens, as a rule, armed with cloth and a special liquid. When finished with the microscope, the immersion lens should be cleaned using a special set. The lens clean with a cotton Bud or swab soaked in alcohol. Removing foreign elements from the lens, do not press down on it, otherwise the lens may simply fall out of the rim.
Particularly neat is to clean the condenser, because the lighting system of the device may be damaged. Do not put pressure on the lens and is strongly dampened it with rubbing alcohol. The housing of the illuminator must be purged by means of a rubber pear.
Clean the metal tripod is performed using a cotton swab dipped in alcohol mixture. Never apply pressure to the body of the microscope. For the comprehensive care of the microscope should fall special kit, which includes wool, flannel wipes, cloths, designed for cleaning lenses, ether, pure alcohol and stick with a pointed tip.
When choosing a microscope it is first necessary to determine the tasks that you intend to impose on him. You should also consider the level of your “skill” with this device, because currently the buyer’s market offers a large assortment, among which you can find options, so to speak, for dummies, and models with more intricate requirements for use.
And, of course, before operation it is necessary at least in General terms to familiarize yourself with the basic requirements for operation and storage of this, is truly, ingenious device.
Recent search terms: