dispersion image disappeared
7. Objectives
Turn the nosepiece to choose the objective and adjust the view field diaphragm and aperture
accordingly
8. View field diaphragm
Adjust the view field diaphragm according to the objective till it_ image touches the edge of
view field as this could eliminate the outside light and increase the contrast of the image.
Notice: There will no image for view field diaphragm when 100X objective is used. So adjust
the diaphragm to it
’s min diameter
Centering view field diaphragm
1_Use the 10X objective and focus the image. Turn the view field diaphragm adjusting
ring with ershins and reduce the diaphragm
’s diameter
__Turn the lifting knob for condenser to focus the image of view field diaphragm
__Turn the two centering screws for condenser and make the image in the center of
view field
__Check the centering and open the view field diaphragm till the image of the
diaphragm touches the edge of view field. Please do the centering again if the image
of the diaphragm doesn
’t touch the edge of view field
__Open the view field diaphragm and make its image a little bigger than the view field in practice
9. Adjusting aperture diaphragm
Adjust the aperture diaphragm adjusting shaft for condenser till the position which stands for
the magnification of objective
_ adjusting the aperture diaphragm
1_Adjust the aperture diaphragm by the adjusting shaft. The brightness and resolution will
be decrease while the contrast and depth of view will increase if the diameter of aperture
diaphragm reduces
2_Adjust the value of aperture diaphragm to 70%-80% of the value of objective
’s N.A.
3_The aperture diaphragm could control the N.A. of condenser. Do not adjusting the
brightness by it while use the brightness adjusting knob to make the adjustment
4_N.A. is marked in each objective
e.g. 40X/0.65 stands for that magnification is 40X and N.A. is 0.65
5_Remove the eyepiece and observe through the eye tubes by eyes directly
N.A. of condenser could tell users the position of aperture diaphragm adjusting shaft in
corresponding magnification. (That is to say, the value of aperture diaphragm should be
70% to 80% of the N.A. of objective when the aperture diaphragm adjusting shaft reaches
some position) If the objective has been changed, please move the shaft to the position with
the same value which is in the objective in the optic path and this will make ideal contrast
10. Observing with oil immersion
There is_ oil_ marked in the oil immersion objective. Please use the oil immersion supplied
by the manufacturer between the objective and cover glass.