Taking lens system
A three-lens-element taking lens system for forming an image on a solid-state image sensor has, from the object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power and having a concave surface pointing to the image side. Of the first and second lens elements, one is a glass lens element and the other is a plastic lens element. The third lens element is a plastic lens element.
1. A three-lens-element taking lens system for forming an image on a solid-state image sensor, comprising, from an object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power and having a concave surface pointing to an image side,
wherein, of the first and second lens elements, one is a glass lens element and the other is a plastic lens element,
wherein the third lens element is a plastic lens element, and
wherein the following condition is fulfilled:
0.3 <f/fG <2.6
where f represents a focal length of the taking lens system as a whole; and
fG represents a focal length of the glass lens element having a positive optical power.
2. A taking lens system as claimed in claim 1 , wherein the first to third lens elements each include at least one aspherical surface.
3. A taking lens system as claimed in claim 1 , wherein the first to third lens elements are each formed of a uniform material.
4. A three-lens-element taking lens system for forming an image on a solid-state image sensor, comprising, from an object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power and having a concave surface pointing to an image side,
wherein, of the first and second lens elements, one is a glass lens element and the other is a plastic lens element,
wherein the third lens element is a plastic lens element, and
wherein the following condition is fulfilled:
0.05 <TG/fG< 1.35
where TG represents an axial thickness of the glass lens element having a positive optical power; and
fG represents a focal length of the glass lens element having a positive optical power.
5. A taking lens system as claimed in claim 4 , wherein the first to third lens elements each include at least one aspherical surface.
6. A taking lens system as claimed in claim 4 , wherein the first to third lens elements are each formed of a uniform material.
7. A three-lens-element taking lens system for forming an image on a solid-state image sensor, comprising, from an object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power and having a concave surface pointing to an image side,
wherein, of the first and second lens elements, one is a glass lens element and the other is a plastic lens element,
wherein the third lens element is a plastic lens element, and
wherein the following condition is fulfilled:
| f 3 |/fP< 2.6
where f3 represents a focal length of the third lens element; and
fP represents a focal length of the plastic lens element having a positive optical power.
8. A taking lens system as claimed in claim 7 , wherein the first to third lens elements each include at least one aspherical surface.
9. A taking lens system as claimed in claim 7 , wherein the first to third lens elements are each formed of a uniform material.
10. A three-lens-element taking lens system for forming an image on a solid-state image sensor, comprising, from an object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power and having a concave surface pointing to an image side,
wherein, of the first and second lens elements, one is a glass lens element and the other is a plastic lens element,
wherein the third lens element is a plastic lens element, and
wherein the following condition is fulfilled:
0.05 <T 3 /f< 0.5
where T3 represents an axial thickness of the third lens element; and
f represents a focal length of the taking lens system as a whole.
11. A taking lens system as claimed in claim 10 , wherein the first to third lens elements each include at least one aspherical surface.
12. A taking lens system as claimed in claim 10 , wherein the first to third lens elements are each formed of a uniform material.
13. A three-lens-element taking lens system for forming an image on a solid-state image sensor, comprising, from an object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power and having a concave surface pointing to an image side,
wherein, of the first and second lens elements, one is a glass lens element and the other is a plastic lens element,
wherein the third lens element is a plastic lens element, and
wherein the following condition is fulfilled:
VG> 58
where VG represents an Abbe number of the glass lens element having a positive optical power.
14. A taking lens system as claimed in claim 13 , wherein the first to third lens elements each include at least one aspherical surface.
15. A taking lens system as claimed in claim 13 , wherein the first to third lens elements are each formed of a uniform material.
16. A three-lens-element taking lens system for forming an image on a solid-state image sensor, comprising, from an object side, a first lens element having a positive optical power, an aperture stop, a second lens element having a positive optical power, and a third lens element having a negative optical power,
wherein, of the first and second lens elements, one is a glass meniscus lens element and the other is a plastic meniscus lens element, and
wherein the third lens element is a plastic meniscus lens element having a concave surface pointing to an image side or a plastic biconcave lens element.
17. A taking lens system as claimed in claim 16 , wherein the following condition is fulfilled:
0.3 <f/fG< 2.6
where f represents a focal length of the taking lens system as a whole; and
fG represents a focal length of the glass lens element having a positive optical power.
18. A taking lens system as claimed in claim 16 , wherein the following condition is fulfilled:
0.05 <TG/fG< 1.35
where TG represents an axial thickness of the glass lens element having a positive optical power; and
fG represents a focal length of the glass lens element having a positive optical power.
19. A taking lens system as claimed in claim 16 , wherein the following condition is fulfilled:
| f 3 |/fP< 2.6
where f3 represents a focal length of the third lens element; and
fP represents a focal length of the plastic lens element having a positive optical power.
20. A taking lens system as claimed in claim 16 , wherein the following condition is fulfilled:
0.05 <T 3 /f< 0.5
where T3 represents an axial thickness of the third lens element; and
f represents a focal length of the taking lens system as a whole.
21. A taking lens system as claimed in claim 16 , wherein the following condition is fulfilled:
VG> 58
where VG represents an Abbe number of the glass lens element having a positive optical power.
22. A taking lens system as claimed in claim 16 , wherein the first to third lens elements each include at least one aspherical surface.
23. A taking lens system as claimed in claim 16 , wherein the first to third lens elements are each formed of a uniform material.