Reading Division Board (Fig. 5)
In (9) eyepiece’s field of vision, the reading window is in the lower part of (8) eyepiece reticule. The range of
reading (8) eyepiece reticule is +/-25D. The graduations between 0 and +/-5D are at an interval of 0.125D.
Those b/-5D and +/-25D are at an interval of 0.25D.
Prism Compensation Device (Fig. 6)
The (6) prism compensation device is needed when measuring a lens diopter value above 5
Δ
. There are two
lines of graduation on the prism compensation device. The upper line measures the angle from 0º to 180º at
5º intervals. The lower line measures prism diopters in the range from 0 to 15
Δ
in each direction at 1
Δ
intervals.
Fig. 6
4
