Table 1 Classification of constraint conditions for the central element. The constraints arise from the sign of the leading and trailing surfaces (positive or negative) as well as the sign of the marginal ray leaving the leading surface (converging or diverging)
From: Orthogonally coupled geometrical constraints in optics design
Leading surface / Trailing surface | Positive | Negative | ||
|---|---|---|---|---|
Positive | Converging (C++) | Diverging (D++) | Converging (C − +) | Diverging (D − +) |
Negative | Converging (C + −) | Diverging (D + −) | Converging (C − −) | Diverging (D − −) |