Optical apparatus
First Claim
1. An optical apparatus comprising at least one negative lens, a meniscus lens that is convex on an object side, an aperture stop, and a double-convex positive lens arranged from the object side to an image side,wherein at least one of the lenses positioned on the object side of the aperture stop and the positive lens include respective aspherical surfaces, andwherein, when va is an average Abbe number of all of the lenses excluding the meniscus lens, vb is an Abbe number of the meniscus lens, f is a focal length of the entire system, f12 is a combined focal length of the negative lens unit and the meniscus lens, ts is a distance between the aperture stop and the positive lens along an axis, L is a distance between a vertex of a lens surface nearest to the object side and a vertex of a lens surface nearest to the image side, t2 is a central thickness of the meniscus lens, θ
- s is an incident angle of a chief ray that passes through the aperture stop at a maximum angle of view, the following Expression 1 is satisfied;
1.4<
va/vb;
0<
ts/L<
0.1
0.2<
t2/L<
0.5;
−
10<
f12/f<
−
1.0; and
25°
<
θ
s<
40°
[Expression 1].
2 Assignments
0 Petitions
Accused Products
Abstract
To provide a high-brightness, small, low-cost optical apparatus which covers a wide-angle to super-wide-angle region and which reliably corrects various aberrations with a small number of lenses.
At least one negative lens unit 1, a meniscus lens 2 that is convex on an object side, an aperture stop S, and a double-convex positive lens 3 are arranged in order from the object side. At least one of the lenses positioned on the object side of the aperture stop S and the positive lens 3 include respective aspherical surfaces. When va is an average Abbe number of all of the lenses excluding the meniscus lens, vb is an Abbe number of the meniscus lens, f is a focal length of the entire system, f12 is a combined focal length of the negative lens unit and the meniscus lens, ts is a distance between the aperture stop and the positive lens along an axis, L is a distance between a vertex of a lens surface nearest to the object side and a vertex of a lens surface nearest to the image side, t2 is a central thickness of the meniscus lens, θs is an incident angle of a chief ray that passes through the aperture stop at a maximum angle of view, 1.4<va/vb, 0<ts/L<0.1, 0.2<t2/L<0.5, −10<f12/f<−1.0, and 25°<θs<40° are satisfied.
15 Citations
10 Claims
-
1. An optical apparatus comprising at least one negative lens, a meniscus lens that is convex on an object side, an aperture stop, and a double-convex positive lens arranged from the object side to an image side,
wherein at least one of the lenses positioned on the object side of the aperture stop and the positive lens include respective aspherical surfaces, and wherein, when va is an average Abbe number of all of the lenses excluding the meniscus lens, vb is an Abbe number of the meniscus lens, f is a focal length of the entire system, f12 is a combined focal length of the negative lens unit and the meniscus lens, ts is a distance between the aperture stop and the positive lens along an axis, L is a distance between a vertex of a lens surface nearest to the object side and a vertex of a lens surface nearest to the image side, t2 is a central thickness of the meniscus lens, θ - s is an incident angle of a chief ray that passes through the aperture stop at a maximum angle of view, the following Expression 1 is satisfied;
1.4<
va/vb;
0<
ts/L<
0.1
0.2<
t2/L<
0.5;
−
10<
f12/f<
−
1.0; and
25°
<
θ
s<
40°
[Expression 1]. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
- s is an incident angle of a chief ray that passes through the aperture stop at a maximum angle of view, the following Expression 1 is satisfied;
-
2. An optical apparatus comprising at least one negative lens, a positive meniscus lens that is convex on an object side, an aperture stop, and a double-convex positive lens arranged from the object side to an image side,
wherein at least one of the lenses positioned on the object side of the aperture stop and the positive lens include respective aspherical surfaces, wherein an amount of correction of sagittal field curvature by the lenses positioned on the object side of the aperture stop is larger than an amount of correction of sagittal field curvature by the positive lens, and wherein, when va is an average Abbe number of all of the lenses excluding the meniscus lens, vb is an Abbe number of the meniscus lens, L is a distance between a vertex of a lens surface nearest to the object side and a vertex of a lens surface nearest to the image side, ts is a distance between the aperture stop and the double-convex lens, and t2 is a central thickness of the meniscus lens, the following Expression 2 is satisfied: -
1.4<
va/vb;
0<
ts/L<
0.1; and
0.2<
t2/L<
0.5
[Expression 2].
-
Specification