12
Fig. 11
are weakest refractive power and strongest refractive power on two mutually
vertical sections.
When this device is used to measure such kind of lens, two long green lines
and three long green lines of drone cannot be focused to be clear simultaneously.
Measurement shall be conducted according to following procedures:
1.
Confirm the mode of spherical lens mesurement.
2.
Turn diopter measuring hand-wheel so that round dot drone is focused
distinctly.
3.
Lightly move lens to enable drone to be positioned at the center of eyepiece
visual field.
4.
Turn astigmatism turning hand-wheel so that two long green lines of round
dot drone and cross-line drone are parallel.
5.
Then finely regulate diopter measuring hand-wheel to obtain clearest focus
of two long green lines of round dot drone and cross-line drone (Fig.11).
6.
By pressing measurement switching key S/C, the device sends out sound of
“Du Du”, and it is switched to mode of cylindrical lens measurement (Fig.12).
