Image lens with high resolution and small distance
An image lens, in the order from the object side to the image side thereof, includes a first lens including a first surface and a second surface, a second lens including a third surface and a fourth surface, a third lens including a fifth surface and a sixth surface, a fourth lens including a seventh surface and a eighth surface, a fifth lens including a ninth surface and a tenth surface, and an image plane. The image lens satisfies the following formulas: (1) D/TTL>0.94; (2) D/L>1.21; wherein D is the maximum image diameter of the image plane; TTL is a total length of the image lens, and L is a distance from an outmost edge of the tenth surface to an optical axis of the image lens along a direction perpendicular to the optical axis.
1. An image lens, in the order from an object side to an image side thereof, comprising:
a first lens having positive refraction power and comprising a first surface facing the object side and a second surface facing the image side;
a second lens having negative refraction power and comprising a third surface facing the object side and a fourth surface facing the image side;
a third lens having positive refraction power and comprising a fifth surface facing the object side and a sixth surface facing the image side;
a fourth lens having positive refraction power and comprising a seventh surface facing the object side and a eighth surface facing the image side;
a fifth lens having negative refraction power and comprising a ninth surface facing the object side and a tenth surface facing the image side; and
an image plane;
wherein the image lens satisfies the following formulas:
D/TTL> 0.94; (1)
D/L> 1.21; (2)
wherein D is the maximum image diameter of the image plane; TTL is a total length of the image lens, L is a distance from an outmost edge of the tenth surface to an optical axis of the image lens along a direction perpendicular to the optical axis of the image lens;
wherein the image lens further satisfies the formulas:
Z/Y> 0; and (3)
wherein Z is a distance from a central point of the seventh surface to an outmost edge of the eighth surface along the optical axis, Y is a distance from an outmost edge of the eighth surface to the optical axis along a direction perpendicular to the optical axis.
2. The image lens as claimed in claim 1 , wherein the image lens further satisfies the formulas:
R 31 /F 3 >R 11 /F 1>0; (4)
R 12 /F 1 <R 32 /F 3<0; (5)
Wherein R 11 is the curvature radius of the first surface of the first lens; R 12 is the curvature radius of the second surface of the first lens; R 31 is the curvature radius of the fifth surface of the third lens, R 32 is the curvature radius of the sixth surface of the third lens; F 1 is focal length of the first lens, and F 3 is focal length of the third lens.
3. The image lens as claimed in claim 2 , wherein the image lens further satisfies the formulas:
R 51 /F 5 <R 52 /F 5<0; (6)
Wherein R 51 is the curvature radius of the ninth surface of the fifth lens; R 52 is the curvature radius of the tenth surface of the fifth lens; F 5 is focal length of the fifth lens.
4. The image lens as claimed in claim 3 , wherein the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth surfaces are aspherical surfaces.
5. The image lens as claimed in claim 4 , wherein the first surface is a convex surface facing the object side, the second surface is a convex surface facing the image side, the third surface is a concave surface facing the object side, and the fourth surface is a concave surface facing the image side, the fifth surface is a convex surface facing the object side, the sixth surface is a convex surface facing the image side, the seven surface is a concave surface facing the object side, the eighth surface is a convex surface facing the image side, the ninth surface is a concave surface facing the object side, the tenth surface is a concave surface facing the image side.
6. The image lens as claimed in claim 5 , wherein the image lens further comprises an aperture stop positioned between the first lens and the second lens.
7. The image lens as claimed in claim 6 , further comprising an IR-cut filter, wherein the IR-cut filter is positioned between the fifth lens and the image plane.