RU97121366A - LIGHT LIGHT - Google Patents

Claims (1)

A fast lens containing four components, the first and second of which are positive menisci convex to the object, the third component is the negative meniscus facing concavity to the image, the fourth component is positive, characterized in that the fourth component is made in the form of a biconvex lens, the following relations hold for this:
0.55f '<f' ₁₂ <0.7f ',
5.5f '<f' ₁₂₃ <7f ',
0.4f '<d ₁ + d ₂ + d ₃ + d ₄ + d ₅ <0.6f',
0.5f '<f' ₄ <0.65f ',
0.2f '<d ₆ <0.3f',
0.5, <r ₃ / r ₄ <0.65,
0.2f '<r ₆ <0.3f',
1.58 <n ₁ = n ₂ = n ₄ <1.65,
where f 'is the focal length of the entire lens;
f _'12 - the focal length of the first, second components,
f ' ₁₂₃ is the focal length of the first, second, third components,
f ' ₄ is the focal length of the fourth component;
d ₁ , d ₂ , d ₃ , d ₄ , d ₅ , d ₆ - thickness and air gaps in the lens;
r ₃ , r ₄ are the radii of curvature of the second component;
r ₆ is the second radius of curvature of the third component;
n ₁ , n ₂ , n ₄ are the refractive indices of the lenses of the first, second and fourth components.