Patent attributes
An image pick-up lens system from an object side to an image side includes an aperture stop (10), and a meniscus-shaped lens (20) having a concave surface on the object side and a convex surface on the image side. The lens has at least one aspheric surface and a diffraction grating provided on the convex surface thereof. The lens system satisfies the following condition: (1) 0.1<R2/R1<0.5, wherein, R1 is an absolute value of a radius of curvature of the concave surface of the lens, and R2 is an absolute value of a radius of curvature of the convex surface of the lens. Condition (1) governs a distribution of refracting power for the lens, in order to correct monochromatic aberrations. The lens system also satisfies other conditions (2)-(4) as disclosed, in order to provide compactness, cost-effectiveness and improved optical performance.
