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00054_Field_54.txt
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1997-10-29
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23 lines
LENS DESIGN
SECONDARY CURVE WIDTH DETERMINATION
If the lens is a tricurve lens, then the
width of at least one of the peripheral
curves must be given. Typically the
3rd curve width is specified. For
example the TCW may be 0.2 mm wide.
If the OAD and OZD are known or given,
which they typically are, then the
width of the secondary can be
determined. The SCW is equal to the
overall lens diameter (OAD) minus the
optical zone diameter (OZD) divided
by 2 minus the TCW.
OAD-OZD
SCW= ---------- - TCW
2
For example, if the OAD is 9.4 mm, OZD is 8.0 mm, TCW is 0.2 mm, the SCW would be 0.5 mm.