摘要 |
Arranging a negative first lens, a positive second lens, a negative third lens, a positive fourth lens, and a positive fifth lens from the object side, in which the image side surface of the fifth lens has an aspherical shape with one or more inflection points and a concave shape toward the image side in a paraxial region, and, when the overall optical length, focal length of the entire lens system, focal length of the first lens, distance between image side surface of the second lens and object side surface of the third lens, refractive index of the second lens, and refractive index of the third lens are taken as TL, f, f1, Dg2-3, N2, and N3 respectively, the image capturing lens is configured to simultaneously satisfy conditional expressions (1a): 1.0≦TL/f≦1.8, (2a): 0.09<Dg2-3/f, (3a): 0.07<|N2−N3|, and (4a): −35≦f1/f≦−2.3. |
主权项 |
1. An image capturing lens substantially consisting of a first lens having a negative power, a second lens having a positive power, a third lens having a negative power, a fourth lens having a positive power, and a fifth lens having a positive power, arranged in this order from the object side, wherein:
the image side surface of the fifth lens has an aspherical shape with one or more inflection points and a concave shape toward the image side in a paraxial region; and the image capturing lens satisfies the following conditional expressions (1a), (2a), (3a), and (4a) simultaneously:
1.0≦TL/f≦1.8 (1a);0.09<Dg2-3/f (2a);0.07<|N2−N3| (3a); and−35≦f1/f≦−2.3 (4a),where:
TL is an overall optical length when a distance from the image side surface of the fifth lens to the image plane is represented by an air equivalent length; f is a focal length of the entire lens system; f1 is a focal length of the first lens; Dg2-3 is a distance (air space) between the image side surface of the second lens and the object side surface of the third lens; N2 is a refractive index of the optical member constituting the second lens; and N3 is a refractive index of the optical member constituting the third lens. |