Optical lens

1. An optical lens, comprising:

a first lens group with a positive refractive power and a second lens group with a positive refractive power arranged in order from a first side to a second side; and

an aperture stop disposed between the first lens group and the second lens group, a total number of lenses with refractive powers in the optical lens being less than four, at least two lenses of the optical lens having an Abbe number of smaller than 50, and the optical lens comprising at least two lenses having an index of refraction of greater than 1.7.

2. The optical lens as claimed in claim 1 , wherein the first lens group comprises a first lens and a second lens with refractive powers, the second lens group comprises a third lens with a refractive power, and the optical lens satisfies one of the following conditions:

(1) the first lens is a meniscus lens, the second lens is a bi-convex lens, and the third lens is a bi-convex lens;

(2) the first lens is an aspheric lens, the second lens is a spherical lens, and the third lens is an aspheric lens.

3. The optical lens as claimed in claim 1 , wherein the optical lens satisfies one of the following conditions:

(1) the optical lens has an aspheric lens between the first side and the aperture stop;

(2) the optical lens has only one aspheric lens between the aperture stop and the second side;

(3) all lenses of the optical lens are made from glass.

4. The optical lens as claimed in claim 1 , wherein an F-number of the optical lens is smaller than or equal to 2.2.

5. The optical lens as claimed in claim 1 , wherein a total lens length of the optical lens is smaller than 20 mm.

6. The optical lens as claimed in claim 1 , wherein a total track length of the optical lens is in the range of 20 to 40 mm.

7. An optical lens, comprising:

a first lens group with a positive refractive power and a second lens group with a positive refractive power arranged in order from a magnified side to a minified side; and

an aperture stop disposed between the first lens group and the second lens group, wherein the first lens group comprises a first lens and a second lens with refractive powers, the second lens group comprises a third lens with a refractive power, and the optical lens satisfies the conditions:

2.5 mm<EFL <3.0 mm and −2.0<L 1 f /EFL <−1.4, where EFL is an effective focal length of the optical lens, and L 1 f is an effective focal length of the first lens.

8. The optical lens as claimed in claim 7 , wherein at least two lenses of the optical lens have an Abbe number of smaller than 50.

9. The optical lens as claimed in claim 7 , wherein the optical lens satisfies one of the following conditions:

(1) the optical lens has an aspheric lens between the magnified side and the aperture stop;

(2) the optical lens has only one aspheric lens between the aperture stop and the minified side;

(3) all lenses of the optical lens are made from glass.

10. The optical lens as claimed in claim 7 , wherein an F-number of the optical lens is smaller than or equal to 2.2.

11. The optical lens as claimed in claim 7 , wherein a total lens length of the optical lens is smaller than 20 mm.

12. The optical lens as claimed in claim 7 , wherein a total track length of the optical lens is in the range of 20 to 40 mm.

13. The optical lens as claimed in claim 7 , wherein the optical lens satisfies one of the following conditions:

(1) the first lens is a meniscus lens, the second lens is a bi-convex lens, and the third lens is a bi-convex lens;

(2) the first lens is an aspheric lens, the second lens is a spherical lens, and the third lens is an aspheric lens.

14. An optical lens, comprising:

a first lens group with a positive refractive power and a second lens group with a positive refractive power arranged in order from a magnified side to a minified side; and

an aperture stop disposed between the first lens group and the second lens group, and the optical lens comprising at least two lenses having an index of refraction of greater than 1.7, wherein the first lens group comprises a first lens with a negative refractive power and a second lens with a positive refractive power, the second lens group comprises a third lens with a positive refractive power, and the optical lens satisfies the condition:

0.2<L 3 D/LT<0.45, where L 3 D is a diameter of a minified-side surface of the third lens, and LT is a total lens length that is a distance along an optical axis between a magnified-side surface of the first lens and the minified-side surface of the third lens, and wherein the optical lens satisfies one of the following conditions:

(1) the first lens is a meniscus lens, the second lens is a bi-convex lens, and the third lens is a bi-convex lens;

(2) the first lens is an aspheric lens, the second lens is a spherical lens, and the third lens is an aspheric lens.

15. The optical lens as claimed in claim 14 , wherein at least two lenses of the optical lens have an Abbe number of smaller than 50.

16. The optical lens as claimed in claim 14 , wherein the optical lens satisfies one of the following conditions:

(1) the optical lens has an aspheric lens between the magnified side and the aperture stop;

(2) the optical lens has only one aspheric lens between the aperture stop and the minified side;

(3) all lenses of the optical lens are made from glass.

17. The optical lens as claimed in claim 14 , wherein an F-number of the optical lens is smaller than or equal to 2.2.

18. The optical lens as claimed in claim 14 , wherein the total lens length LT of the optical lens is smaller than 20 mm.

19. The optical lens as claimed in claim 14 , wherein a total track length of the optical lens is in the range of 20 to 40 mm.

20. The optical lens as claimed in claim 14 ,

wherein the optical lens satisfies the conditions:

2.5 mm<EFL <3.0 mm and −2.0<L 1 f /EFL <−1.4, where EFL is an effective focal length of the optical lens, and L 1 f is an effective focal length of the first lens.