Methods and steps of using reading microscope
How to use:
1. Place the instrument on the measured object, so that the measured part of the measured object is illuminated by natural light or light, and then adjust the eyepiece screw, so that the reticle and the object image can be seen clearly in the field of view at the same time;
2. When measuring, firstly rotate the reading drum to move the glass reticle engraved with filaments, and at the same time slightly rotate the reading microscope to align the vertical filaments with the measured part for measuring;
3. An enlarged round hole dent is seen in the field of view. When measuring, first rotate the reading drum to make the vertical filament in the field of view tangent to one side of the round hole dent to get a reading, and then rotate the reading drum to make the vertical filament tangent to the other side of the round hole dent to get another reading;
4. If the diameter of round hole dent is the difference of secondary reading, it is the insulation thickness.
Precautions:
1. When the instrument can be used normally, it must not be disassembled by itself, otherwise it will cripple the original accuracy of the instrument;
2. When the instrument is stored and used, dust, humidity, supercooling and overheating, and steam containing acid and alkali should be avoided;
3. If there is dirt on the lens surface, it must be wiped with soft objects, such as absorbent cotton, soft brush and lens paper. When it comes to oily dirt, you can gently wipe it with absorbent cotton dipped in a little mixture of alcohol and ether.
Three examples:
1. Place the micrometer microscope on the surface of the measured object, with the notch of the lens seat facing the direction of light. Press and hold the lens seat (8) to adjust the eyepiece (2) so that the dividing line in the visual field can be clearly adjusted. Turn the lens seat focusing ring (7) to make the measured object magnified by the objective lens and clearly imaged on the eyepiece dividing ruler (3). Loosen and lock the lens seat (1), then lock the measured object again, and turn the micrometer drum. At the boundary of the area to be measured, read the integer value on the fixed ruler plus the tail value on the micrometer drum as the starting point reading (a), then rotate the micrometer drum to aim at the other end boundary of the area to be measured on the reticle with cross and double score lines, read the integer value on the fixed ruler plus the tail value on the micrometer drum as the end reading (b) of the boundary of the object to be measured, and the difference between the two readings (a-b
2 Measuring Newton's Ring with Reading Microscope
Measuring the radius of curvature of lens with Newton's ring.
Put the convex surface of a plano-convex lens with a large radius of curvature on a flat glass plate, and keep point contact. At this time, if the air layer is illuminated by vertical monochromatic light, there will be interference on the upper and lower surfaces of the air layer outside the contact point, and it is a light and dark halo centered on the contact point, which is called Newton circle in physics. Because the thickness of the air layer at the bright (or dark) circle is equal, it is called equal thickness interference.
Application of equal thickness interference experiment
1. Measure the radius of curvature of lens with Newton's ring.
Put the convex surface of a plano-convex lens with a large radius of curvature on a flat glass plate, and keep point contact. At this time, if the air layer is illuminated by vertical monochromatic light, there will be interference on the upper and lower surfaces of the air layer outside the contact point, and it is a light and dark halo centered on the contact point, which is called Newton circle in physics. Because the thickness of the air layer at the bright (or dark) circle is equal, it is called equal thickness interference.
According to the theory of equal thickness interference, it can be inferred that
Where: R is the radius of curvature of convex lens, λ is the wavelength of monochromatic light.
Dm,Dn—— the diameters of the m and n turns, measured by a reading microscope.
In the experiment: generally | m-n | ≥ 5, and select 5~10 groups of different combinations of Dm and Dn, so as to eliminate the system error.
