JP2014137483A5 - - Google Patents

Description

The imaging apparatus according to the present invention includes a first lens unit having a negative refractive power and a second lens group having a positive refractive power in order from the object side to the image side, and the first lens unit during zooming from the wide angle end to the telephoto end. In an imaging apparatus having a zoom lens in which a lens group and the second lens group move on an optical axis and an interval between adjacent lens groups is changed , and an image sensor that receives an image formed by the zoom lens,
The imaging range at the wide-angle end and the telephoto end are different, and the formed image heights at the wide-angle end and the telephoto end of a light beam emitted from an object located at infinity and incident at a shooting half angle of view θ are respectively Yw∞ and Yt∞. The wide angle when the image height at the wide-angle end and the telephoto end of the light beam emitted from an object located at a close distance and incident at a shooting half angle of view θ is focused on an object at Yw, Yt, and infinity, respectively. When the focal lengths of the entire system at the end and the telephoto end are fw∞ and ft∞, respectively, the focal length fi is fw∞ <fi <ft∞.
In the zoom position that satisfies
When the image height at the focal length fi of the light beam incident at the shooting half angle of view θ is Yi,
1.80 ≦ Yt∞ / Yw∞ ≦ 2.5
1.60 ≦ Yt close / Yw close <1.80
However, Yi = 2 × fi × sin (θ / 2) (85 ° ≦ θ ≦ 90 °)
The following conditional expression is satisfied, and the first lens group includes a light shielding member having a variable or fixed aperture diameter.

In addition, the zoom lens of the present invention has a first lens group having a negative refractive power and a second lens group having a positive refractive power in order from the object side to the image side, and during zooming from the wide-angle end to the telephoto end. In a zoom lens in which the first lens group and the second lens group move on the optical axis, and the interval between adjacent lens groups changes , the first lens group shields part of the maximum off-axis light beam at the wide angle end, and telephoto A light-shielding member having a variable or fixed aperture diameter that does not shield the maximum off-axis light beam at the end is characterized.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The imaging apparatus of the present invention includes a first lens group having a negative refractive power and a second lens group having a positive refractive power in order from the object side to the image side, and the first lens is used for zooming from the wide angle end to the telephoto end. There is a zoom lens in which the group and the second lens group move on the optical axis, and the interval between the adjacent lens groups changes . In addition, an image sensor that receives an image formed by the zoom lens is provided.

The imaging apparatus according to the present invention includes a first lens unit L1 having a negative refractive power and a second lens unit L2 having a positive refractive power in order from the object side to the image side, and performs first zooming from the wide angle end to the telephoto end. The first lens unit L1 and the second lens unit L2 have a zoom lens that moves on the optical axis and changes the interval between adjacent lens units . An image sensor that receives an image formed by the zoom lens is included. The imaging range at the wide-angle end and the telephoto end are different. Let Yw∞ and Yt∞ be the image heights at the wide-angle end and the telephoto end of the light beam incident at an infinitely far object at the shooting half angle of view θ. The image heights at the wide-angle end and the telephoto end of a light beam emitted from an object located at a close distance and incident at an imaging half angle of view θ are respectively close to Yw and Yt.

The focal lengths of the entire system at the wide-angle end and the telephoto end when focusing on an object at infinity are fw∞ and ft∞, respectively. At this time, the focal length fi is fw∞ <fi <ft∞.
In a zoom position that satisfies the above, let Yi be an image height at the focal length fi of a light beam incident at a shooting half angle of view θ. At this time,
1.80 ≦ Yt∞ / Yw∞ ≦ 2.5 (1)
1.60 ≦ Yt close / Yw close <1.80 (2)
However, Yi = 2 × fi × sin (θ / 2) (85 ° ≦ θ ≦ 90 °)
The following conditional expression is satisfied.

The first lens unit L1 includes a light shielding member whose aperture diameter is variable or fixed during zooming or focusing. Further, the photographing half angle of the light beam focused on the imaging image height Y in when focusing on an object at infinity in the imaging device of the present invention Shita∞, Yuizozo in when focusing on a close object Let θ mod be the shooting half angle of view of the light beam focused at high Y. At this time,
0.67 <θ∞ / θmod ≦ 1 (3)
The following conditional expression is satisfied. The light shielding member is disposed on the image side of the lens located closest to the object side in the first lens group .

In addition, in the image pickup apparatus of the present invention, the second light-shielding member that shields the maximum field-angle light beam at the telephoto end without shielding the maximum field-angle light beam (the most off-axis light beam) (maximum field-angle light beam) at the wide-angle end is the most object. It is arrange | positioned at the outer peripheral side of the lens located in the side.

1.80 ≦ Yt∞ / Yw∞ ≦ 2.2 (1a)
However, Y = 2 × f × sin (θ / 2) (85 ° ≦ θ ≦ 90 °)
Many common screen sizes have an aspect ratio of 2: 3. In order to include from the circumference fisheye to the diagonal fisheye in the screen size of this ratio, at least the numerical value of the conditional expression (1) is preferably 1.8 or more.

The light-shielding member LC according to the present invention takes advantage of its characteristics and does not significantly affect the light beam L (T) on the telephoto side as shown in FIG. 2 (e), and only the light beam L (W) on the wide-angle side is increased. It is arranged so as to be shielded from light. As shown in FIG. 2 (e), the light blocking member LC is not shield the light flux of the most off-axis light flux (a half field angle of 90 degrees) at the telephoto end, the outermost off-axis light beam at the wide angle end (half angle of 90 degrees) It has an aperture diameter that blocks a part of the light beam. Further, during zooming from the wide-angle end to the telephoto end, the distance (height) from the optical axis through which incident light having the same angle of view passes varies. Therefore, the inner diameter of the light shielding member LC used in the present invention may be variable.

Claims (7)

In order from the object side to the image side, the first lens group having a negative refractive power and the second lens group having a positive refractive power are provided, and the first lens group and the second lens are used for zooming from the wide angle end to the telephoto end. In an imaging apparatus having a zoom lens in which a group moves on an optical axis and an interval between adjacent lens groups changes , and an imaging element that receives an image formed by the zoom lens,
The imaging range at the wide-angle end and the telephoto end are different, and the formed image heights at the wide-angle end and the telephoto end of a light beam emitted from an object located at infinity and incident at a shooting half angle of view θ are respectively Yw∞ and Yt∞. The wide angle when the image height at the wide-angle end and the telephoto end of the light beam emitted from an object located at a close distance and incident at a shooting half angle of view θ is focused on an object at Yw, Yt, and infinity, respectively. When the focal lengths of the entire system at the end and the telephoto end are fw∞ and ft∞, respectively, the focal length fi is fw∞ <fi <ft∞.
In the zoom position that satisfies
When the image height at the focal length fi of the light beam incident at the shooting half angle of view θ is Yi,
1.80 ≦ Yt∞ / Yw∞ ≦ 2.5
1.60 ≦ Yt close / Yw close <1.80
However, Yi = 2 × fi × sin (θ / 2) (85 ° ≦ θ ≦ 90 °)
An imaging apparatus characterized by satisfying the following conditional expression and having a light shielding member with a variable or fixed aperture diameter inside the first lens group. When the focal lengths of the entire system at the wide-angle end and the telephoto end when focusing on an object at infinity are fw∞ and ft∞, respectively, the focal length fi is fw∞ <fi <ft∞.
In the zoom position that satisfies
The imaging half angle of the light beam focused on the imaging image height Y in when focusing on an object at infinity Shita∞, the light beam forms an image on the imaging image height Y in when focusing on a close object When the shooting half angle of view is θ mod,
0.67 <θ∞ / θmod ≦ 1
The imaging apparatus according to claim 1 , wherein the following conditional expression is satisfied. The light blocking member, an imaging apparatus according to claim 1 or 2, characterized in that arranged on the image side of the lens positioned closest to the object side in the first lens group. A second light-shielding member that does not shield the most off-axis light beam at the wide-angle end and shields the most off-axis light beam at the telephoto end is further provided on the outer peripheral side of the lens located closest to the object side in the first lens group. The imaging apparatus according to any one of claims 1 to 3, wherein The light shielding member shields a portion of the outermost off-axis light beam at the wide-angle end, the imaging according to any one of claims 1 to 4, characterized in the go, such shields the outermost off-axis light beam at the telephoto end apparatus. In order from the object side to the image side, it has a first lens group having a negative refractive power and a second lens group having a positive refractive power,
In a zoom lens in which the first lens group and the second lens group move on the optical axis during zooming from the wide-angle end to the telephoto end, and the interval between adjacent lens groups changes .
The inside of the first lens group, and shielding a part of the outermost off-axis light beam at the wide-angle end, the zoom lens characterized by having a light-shielding and a decoction shielding light member outermost off-axis light beam at the telephoto end. A second light-shielding member that does not shield the most off-axis light beam at the wide-angle end and shields the most off-axis light beam at the telephoto end is further provided on the outer peripheral side of the lens located closest to the object side in the first lens group. the zoom lens according to claim 6, wherein.