Three element optical system
View Patent ↗An optical system is provided. In order from an object side to an image side, the optical system includes a first lens element having a positive power, a meniscus shape, and an object side surface. The object side surface of the first lens element is convex toward the object side. A second lens element has a negative power, a meniscus shape, and an object side surface. The object side surface of the second lens element is concave toward the object side. A third lens element has a positive power. An aperture stop is positioned on or in front of an object side of the first lens element.
1. An optical system comprising:
a first lens element having a positive power, a meniscus shape, and an object side surface, the object side surface of the first lens element being convex toward the object side;
a second lens element having a negative power, a meniscus shape, and an object side surface, the object side surface of the second lens element being concave toward the object side;
a third lens element having a positive power, the first, second, and third lens elements being in order from an object side to an image side of the optical system; and
an aperture stop positioned on an object side of the first lens element, wherein the positive power of the first lens element is stronger than the positive power of the third lens element.
2. The optical system according to claim 1 , wherein the first lens element is a singlet.
3. The optical system according to claim 1 , wherein the aperture stop is positioned on the object side surface of the first lens element.
4. The optical system according to claim 1 , further comprising:
a light vignetting aperture located between the first and second lens elements.
5. The optical system according to claim 1 , wherein the first, second, and third lens elements are made from resin materials.
6. The optical system according to claim 1 , the optical system having an effective focal length f 0 , a total length L defining the distance between the vertex of the object side surface of the first lens element and an image plane located at an air equivalent back focus, wherein the optical system satisfies the condition L/f 0 <1.20.
7. The optical system according claim 6 , wherein the first lens element is made from a material having an Abbe V-number, V d >65.
8. The optical system according claim 1 , wherein the optical system has a half field of view in object space of at least 25 degrees.
9. The optical system according claim 1 , wherein the optical system has a relative aperture of less than f/4.
10. The optical system according claim 1 , wherein all of the lens elements have an index of refraction of less than 1.60.
11. The optical system according to claim 1 , wherein the first lens element is made from a material having an Abbe V-number, V d >65.
12. The optical system according to claim 1 , wherein at least one of the lens elements is made from a resin material having a glass transition temperature, T g >300° F.
13. The optical system according to claim 1 , wherein at least one of the lens elements is made from a nanocomposite optical material.
14. The optical system according to claim 1 , wherein the first lens element is spherical, the second lens element is aspheric, and the third lens element is spherical.
15. The optical system according to claim 1 , wherein the first lens element is spherical, the second lens element is bi-aspheric, and the third lens element is spherical.
16. The optical system according to claim 15 , wherein the first lens element is made from a glass, the second lens element is made from a resin material, and the third lens element is made from a glass.
17. The optical system according to claim 15 , wherein the first lens element is made from a glass, the second lens element is made from a resin material, and the third lens element is made from a resin material.
18. The optical system according to claim 15 , wherein the first lens element is made from a resin material, the second lens element is made from a resin material, and the third lens element is made from a glass.
19. The optical system according to claim 15 , wherein the first, second, and third lens elements are made from resin materials.
20. The optical system according to claim 1 , wherein the first lens element is aspheric, the second lens element is spherical, and the third lens element is aspheric.
21. The optical system according to claim 20 , wherein the first lens element is made from a resin material, the second lens element is made from a glass, and the third lens element is made from a resin material.
22. The optical system according to claim 20 , wherein the first, second, and third lens elements are made from resin materials.
23. The optical system according to claim 1 , wherein the first lens element is aspheric, the second lens element is aspheric, and the third lens element is spherical.
24. The optical system according to claim 23 , wherein the first lens element is made from a resin material, the second lens element is made from a resin material, and the third lens element is made from a glass.
25. The optical system according to claim 23 , wherein the first, second, and third lens elements are made from resin materials.
26. The optical system according to claim 1 , wherein the first lens element is aspheric, the second lens element is aspheric, and the third lens element is aspheric.
27. The optical system according to claim 26 , wherein the first, second, and third lens elements are made from resin materials.
28. The optical system according to claim 1 , wherein the maximum chief ray angle in air with respect to the image surface normal is less than 20°, where chief rays are defined as rays that pass through the center of the aperture stop.
29. An optical system comprising:
a first lens element having a positive power, a meniscus shape, and an object side surface, the object side surface of the first lens element being convex toward the object side;
a second lens element having a negative power, a meniscus shape, and an object side surface, the object side surface of the second lens element being concave toward the object side;
a third lens element having a positive power, the first, second, and third lens elements being in order from an object side to an image side of the optical system;
an aperture stop positioned on an object side of the first lens element; and
a light vignetting aperture located between at least one of the first and second lens elements, and the second and third lens elements.
30. An optical system comprising in order from an object side to and image side:
a first lens element having a positive power, a meniscus shape, and an object side surface, the object side surface of the first lens element being convex toward the object side;
a second lens element having a negative power, a meniscus shape, and an object side surface, the object side surface of the second lens element being concave toward the object side;
a third lens element having a positive power, the first, second, and third lens elements being in order from an object side to an image side of the optical system; and
an aperture stop positioned on an object side of the first lens element, the optical system having an effective focal length f 0 , a total length L defining the distance between the vertex of the object side surface of the first lens element and an image plane located at an air equivalent back focus, wherein the optical system satisfies the condition L/f 0 <1.20.