Optical image collecting system
An optical image collecting system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with positive refractive power has a convex object-side surface. The second through sixth lens elements all have refractive power. The fifth lens element has a concave object-side surface and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fifth lens element is aspheric. The sixth lens element has a concave image-side surface at a paraxial region, wherein the image-side surface of the sixth lens element changes from concave at the paraxial region to convex at a peripheral region, and both of an object-side surface and the image-side surface of the sixth lens element are aspheric.
1. An optical image collecting system comprising, in order from an object side to an image side thereof:
a first lens element with positive refractive power having a convex object-side surface;
a second lens element having refractive power;
a third lens element having refractive power;
a fourth lens element having refractive power;
a fifth lens element with refractive power having a concave object-side surface and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fifth lens element is aspheric; and
a sixth lens element with refractive power having a concave image-side surface at a paraxial region, wherein the image-side surface of the sixth lens element changes from concave at the paraxial region to convex at a peripheral region, and both of an object-side surface and the image-side surface of the sixth lens element are aspheric,
wherein the said optical image collecting system has a total of six lens elements with refractive power; and
wherein a focal length of the optical image collecting system is f, a focal length of the fifth lens element is f5, a vertical distance between a non-axial critical point on the image-side surface of the sixth lens element and an optical axis is Yc62, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, and the following relationships are satisfied:
−1.3 <f/f 5<0.7;
0.15 <Yc 62 /f< 0.50;
and
4.6 <f /( CT 3 +CT 4 +CT 5)<7.0.
2. The optical image collecting system of claim 1 , wherein the second lens element has negative refractive power and a concave image-side surface.
3. The optical image collecting system of claim 2 , wherein the object-side surface of the sixth lens element is convex at a paraxial region.
4. The optical image collecting system of claim 3 , wherein the fourth lens element has positive refractive power.
5. The optical image collecting system of claim 4 , wherein the second lens element has a convex object-side surface.
6. The optical image collecting system of claim 4 , wherein the first lens element has a concave image-side surface.
7. The optical image collecting system of claim 4 , wherein the fifth lens element has negative refractive power.
8. The optical image collecting system of claim 2 , wherein the focal length of the optical image collecting system is f, the central thickness of the third lens element is CT3, the central thickness of the fourth lens element is CT4, the central thickness of the fifth lens element is CT5, and the following relationship is satisfied:
4.85 <f /( CT 3 +CT 4 +CT 5)<6.5.
9. The optical image collecting system of claim 2 , wherein a vertical distance between a non-axial critical point on the object-side surface of the sixth lens element and an optical axis is Yc61, the vertical distance between a non-axial point on the image-side surface of the sixth lens element and the optical axis is Yc62, and the following relationship is satisfied:
Yc 62 >Yc 61.
10. The optical image collecting system of claim 2 , wherein the focal length of the optical image collecting system is f, the focal length of the fifth lens element is f5, and the following relationship is satisfied:
−0.7 <f/f 5<0.5.
11. The optical image collecting system of claim 10 , wherein an Abbe number of the first lens element is V1, an Abbe number of the fifth lens element is V5, and the following relationship is satisfied:
0.3 <V 5 /V 1<0.6
12. The optical image collecting system of claim 10 , wherein the focal length of the optical image collecting system is f, a focal length of the third lens element is f3, the focal length of the fifth lens element is f5, a focal length of the sixth lens element is f6, and the following relationship is satisfied:
0.2 <|f/f 3 |+|f/f 5 |+|f/f 6|<1.0.
13. The optical image collecting system of claim 10 , wherein at least one stop is disposed between the third lens element and the sixth lens element.
14. The optical image collecting system of claim 10 , wherein at least four lens elements with refractive power among the first through sixth lens elements of the optical image collecting system have a central thickness less than or equal to 0.300 mm.
15. An optical image collecting system comprising, in order from an object side to an image side thereof:
a first lens element with positive refractive power having a convex object-side surface;
a second lens element with negative refractive power having a concave image-side surface;
a third lens element having refractive power;
a fourth lens element having refractive power;
a fifth lens element with refractive power having a concave object-side surface and a convex image-side surface; and
a sixth lens element with refractive power having a concave image-side surface at a paraxial region, wherein the image-side surface of the sixth lens element changes from concave at the paraxial region to convex at a peripheral region, and both of an object-side surface and the image-side surface of the sixth lens element are aspheric,
wherein the optical image collecting system has a total of six lens elements with refractive power; and
wherein a focal length of the optical image collecting system is f, a focal length of the fifth lens element is f5, a vertical distance between a non-axial critical point on the image-side surface of the sixth lens element and an optical axis is Yc62, a curvature radius of an object-side surface of the fourth lens element is R7, a curvature radius of an image-side surface of the fourth lens element is R8, and the following relationships are satisfied:
−1.3 <f/f 5<0.7;
0.15 <Yc 62 /f< 0.50;
and
−2.0<( R 7 +R 8)/( R 7 −R 8)<0.6.
16. The optical image collecting system of claim 15 , wherein a curvature radius of the object-side surface of the sixth lens element is R11, a curvature radius of the image-side surface of the sixth lens element is R12, and the following relationship is satisfied:
0.2 <R 12 /R 11<1.5.
17. The optical image collecting system of claim 16 , wherein the focal length of the optical image collecting system is f, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, and the following relationship is satisfied:
4.0 <f /( CT 3 +CT 4 +CT 5)<9.0.
18. The optical image collecting system of claim 16 , wherein the fourth lens element has positive refractive power, the curvature radius of the image-side surface of the sixth lens element is R12, a focal length of the second lens element is f2, and the following relationship is satisfied:
−0.6 <R 12 /f 2<0.
19. The optical image collecting system of claim 16 , wherein a central thickness of the fifth lens element is CT5, a central thickness of the sixth lens element is CT6, and the following relationship is satisfied:
0.20 <CT 5 /CT 6<0.65.
20. The optical image collecting system of claim 15 , wherein a curvature radius of the object-side surface of the fifth lens element is R9, a curvature radius of the image-side surface of the fifth lens element is R10, and the following relationship is satisfied:
−0.30<( R 9 −R 10)/( R 9 +R 10)<0.20.
21. The optical image collecting system of claim 20 , wherein an axial distance between the first lens element and the second lens element is T12, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, an axial distance between the fifth lens element and the sixth lens element is T56, and the following relationship is satisfied:
0.15<( T 12 +T 34 +T 56)/( T 23 +T 45)<0.90.
22. The optical image collecting system of claim 20 , wherein all of the lens elements with refractive power are made of plastic material, and each of the object-side surface and the image-side surface of every lens element is aspheric;
the object-side surface of the sixth lens element is convex at a paraxial region; a vertical distance between a non-axial critical point on the object-side surface of the sixth lens element and an optical axis is Yc61, the vertical distance between a non-axial point on the image-side surface of the sixth lens element and an optical axis is Yc62, and the following relationship is satisfied:
Yc 62 >Yc 61.