Super wide angle optical lens system
The present invention relates to a super wide angle optical lens system reduced in size and weight and increased in definition for various electronic devices and vehicles while capable of obtaining satisfactory optical performance, an appropriate wide field angle and exhibiting high image quality and broad image data, thereby reducing distortion of an image.
1. An optical lens comprising of, in adjacent order, from an object side of the optical lens:
a first lens being a negative meniscus lens;
a second lens having a negative refractive power;
a third lens being a negative meniscus lens with a convex image side surface;
a fourth lens having a positive refractive power with a convex image side surface;
a fifth lens having a negative refractive power with a concave object side surface; and
a sixth lens having a positive refractive power with a convex object side surface.
2. The optical lens of claim 1 , wherein at least one of the six lenses satisfies the following conditional expression:
3.0<θ d /TL< 9.0
where, θ d represents a maximum half field angle of an optical system, and TL represents a distance from an object-side surface of a lens closest to the object side to an image forming surface.
3. The optical lens of claim 2 , wherein the fourth and fifth lenses form one lens group, the fourth and fifth lenses cemented together or spaced apart from each other at a predetermined distance.
4. The optical lens of claim 2 , further comprising an aperture stop disposed between the third and fourth lenses to adjust light amount.
5. The optical lens of claim 2 , wherein a curvature radius of an object side surface of the first lens is larger than that of an image side surface.
6. The optical lens of claim 2 , wherein a curvature radius of an image side surface the third lens is larger than that of an object side surface.
7. The optical lens of claim 1 , wherein the second lens has at least one of both surfaces formed of an aspheric surface.
8. The optical lens of claim 1 , wherein the sixth lens has at least one of both surfaces formed of an aspheric surface.
9. The optical lens of claim 2 , further comprising an IR (Infrared) filter between the sixth lens and the image forming surface.
10. The optical lens of claim 1 , further comprising a cover glass between the sixth lens and an image forming surface.
11. The optical lens of claim 1 , wherein a curvature radius of an object side surface of the first lens is larger than that of an image side surface.
12. The optical lens of claim 1 , wherein a curvature radius of an image side surface the third lens is larger than that of an object side surface.
13. The optical lens of claim 1 , wherein the second and sixth lenses are plastic lenses.
14. The optical lens of claim 1 , wherein the fourth and fifth lenses form one lens group, the fourth and fifth lenses cemented together or spaced apart from each other at a predetermined distance.
15. The optical lens of claim 1 , further comprising an aperture stop disposed between the third and fourth lenses to adjust light amount.
16. The optical lens of claim 1 , wherein at least one of the lenses satisfies the following conditional expression:
0.30< Y /( f ×tan θ d )<0.60
where, θ d represents a maximum half field angle of an optical system, Y represents a maximum image height (mm), and f represents focal length (mm) of the optical system.
17. The optical lens of claim 1 , wherein the total number of lenses is six.