JP3272413B2 - Decenterable lens and vibration compensation lens system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decenterable lens and a vibration compensation lens system using the same.

[0002]

2. Description of the Related Art When photographing from an automobile or an aircraft, or when using a long focal length lens, image degradation due to the effects of blurring tends to be remarkable, and various proposals have conventionally been made on means for compensating for the effects of blurring. It has been done.

As a conventional technique for vibration compensation, for example, Japanese Patent Laid-Open No. 57-7416 discloses a variable apex prism in which a transparent liquid is sealed between two plane plates in a taking lens.
An apparatus is disclosed that compensates for image movement by changing the vertex angle of a prism in response to vibration.

[0004]

However, in the above-mentioned conventional vibration compensating lens system, the flat plate has only the function of holding the liquid, and it cannot be said that it is effectively used as an optical material. In addition, one variable apex angle prism has four boundaries of the medium, which are likely to cause a light amount loss and a ghost due to reflection at the boundary surface.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and has been made in view of the above-mentioned problems. The aim is to get a lens.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, a decenterable lens according to the present invention has a flat surface between two lenses or lens groups, and a closed space between these flat surfaces. It is characterized in that it is formed so as to enclose a transparent liquid, and that the optical axes of the two lenses or the lens groups can be relatively inclined by an external force.

Further, the vibration compensating lens of the present invention includes the decenterable lens configured as described above in a lens group,
It is characterized in that the relative inclination of the optical axis is adjusted according to the vibration.

[0008]

Embodiments of the present invention will be described below.

The embodiment is a vibration compensating lens system including a decenterable lens according to the present invention. For example, as shown in FIG. 1, the vibration compensating lens system includes seven lenses represented by a first surface r1 to a thirteenth surface r13. Normal fixed lens group A and the fourteenth surface r14
To the seventeenth surface r17, and a decenterable lens B composed of a liquid prism constituted by enclosing a liquid in a sealed space formed by opposing planes of these lenses. I have.

In the eccentric lens B of this example, the sixteenth surface r
A concave lens composed of the sixteenth surface and the seventeenth surface r17 is provided so as to be tiltable with respect to the entire optical axis. The tilt changes the apex angle of the liquid prism and deflects the optical path, thereby tilting the entire system. Is configured to compensate for image movement due to

In order to suppress the occurrence of color misregistration during deflection by the liquid prism, it is desirable to use a liquid with a small dispersion. In addition, although it is possible to provide an aberration correction effect on the boundary surface by the refractive index difference between the lens provided with the liquid and the liquid, it is possible to reduce the refractive index difference to reduce the reflectance of the light beam at the boundary surface. It is effective for lowering and reducing the ghost due to reflection.

Since the decenterable lens B has two lenses that serve both as a lens function and for holding a liquid, a variable apex angle prism composed of a parallel plane plate as in the prior art and a normal lens are used. The effect of one sheet can be provided at the same time. By integrating components having two functions, the boundary surface of the medium can be reduced by two, and the influence of reflection can be reduced.

In particular, when the optical element is arranged in strong converging light or strong diverging light, if the plane on the incident side and the plane on the exit side are flat, a large aberration will be generated in these planes. It is desirable to deflect the optical path by tilting these surfaces as surfaces that are substantially perpendicular to the paraxial principal ray or surfaces that are substantially perpendicular to the marginal ray.

In general, a liquid has a large refractive index change due to a temperature change. Therefore, if a configuration is provided in which a liquid prism portion is given power to correct aberration, a focus shift occurs due to a temperature change in an imaging optical system. . Therefore, it is important not to give power to the liquid prism, and the opposing surfaces of the lenses sandwiching the liquid need to be flat.

Further, when the decenterable lens of the present invention is compared with a conventional variable apex angle prism, the thickness of the parallel flat plate used for filling the liquid is reduced, so that the overall length of the lens is reduced in optical design. And vignetting of the off-axis light beam can be reduced, which is effective in reducing the size of the entire lens.

[0016]

FIG. 1 is a lens configuration diagram of a vibration compensation lens system according to a first embodiment when the lens is not decentered. This lens system is an inner focus type telephoto lens having an F number of 1: 5.6 and a focal length of 400 mm, and has an eccentric lens B closest to the image side. The decenterable lens B is formed by separating one meniscus convex lens that contributes to the light condensing action, the correction of distortion, and the like in the middle, and sealing the liquid therebetween.

The specific numerical configuration of the first embodiment is shown in Table 1. In the table, FNO. Is the F number, f is the focal length, ω is the half angle of view, r is the radius of curvature, d is the lens thickness or air gap,
n is the refractive index at d-line (588 nm), and ν is the Abbe number.

[0018]

[Table 1] FNO = 1: 5.6 f = 400.00 fB = 117.42
ω = 3.1 °

FIG. 2 shows the spherical aberration SA, sine condition SC, d-line, and g of the vibration compensating lens of Example 1 when the lens is not decentered.
Line, chromatic aberration indicated by spherical aberration in the C line, chromatic aberration of magnification, astigmatism (S: sagittal, M: meridional),
The figure shows distortion.

FIG. 3 shows that the most image-side plano-concave lens is set to 3.4 when the lens system of Embodiment 1 is tilted by 0.5 ° as a whole.
FIG. 6 is a lens cross-sectional view when a light beam incident parallel to an optical axis before tilting is corrected by being tilted by 7 ° so that an image is formed on the tilted optical axis.

FIG. 4 is a spot diagram on the image plane after the state of FIG. 3, that is, the tilt of the lens system is corrected by the decenterable lens. (a), (b), and (c) show image heights of 21.6 mm and 0 mm, respectively, if the lens system is not tilted.
(Incident angle: 0 °), the state of the light beam which forms an image at -21.6 mm after falling down is shown.

When the correction by the eccentric lens is not performed, the moving amount of the image is expressed by f, where f is the focal length and θ is the tilt angle.
2. In the case of the lens system of Example 1, it is expressed by tan θ.
It becomes 49mm. Compared with this movement amount, the swelling amount of the spot is about 1/10 even at the outermost peripheral portion where deterioration is most severe, and it can be understood from the spot diagram that the movement of the image can be corrected well.

It should be noted that the spot diagram in the case of an incident angle of 0 ° shown in FIG. 4B is separated into two parts because the spot diagram of the C, d, e, F, g lines This is because the image is displayed using only five colors.

[0024]

Second Embodiment FIG. 5 shows a cross section of a vibration compensating lens according to a second embodiment when the lens is not decentered. The specific numerical configuration is shown in Table 2. FIG.
Various aberrations due to this configuration are shown.

In the lens system according to the second embodiment, the convex / planar lens provided closest to the object side is divided into a convex / planar lens and a plane-parallel plate, and a liquid is sealed between them to form a decenterable lens.

[0026]

[Table 2] FNO = 1: 5.7 f = 400.00 fB = 84.60
ω = 3.1 °

In this embodiment, when the whole lens system is tilted by 0.5 °, the parallel plane plate of the eccentric lens is tilted by 4.89 °, so that the light beam incident parallel to the optical axis before tilting is tilted. Correction can be made so that an image is formed on the optical axis.

FIG. 7 is a spot diagram on the image plane after the tilt of the lens system of 0.5 ° is corrected by the decenterable lens. Three spot diagrams (a), (b),
(c) shows an image height of 21.6 mm, 0 mm (incident angle 0 °), and −2 if the lens system is not tilted, as in the first embodiment.
This shows a state after a light beam which forms an image at 1.6 mm has fallen.

[0029]

Third Embodiment FIG. 8 shows a cross section of a vibration compensation zoom lens according to a third embodiment at the short focal length extremity when the lens is not decentered. Specific numerical configurations are shown in Tables 3 and 4. FIGS. 9, 10 and 11 are graphs showing various aberrations at a focal length of 39 mm, 70 mm and 102 mm, respectively, when the lens is not decentered.

The lens system of the third embodiment has a configuration in which a convex plano lens represented by a tenth surface r10 and an eleventh surface r11 and a cemented plano-convex lens represented by a twelfth surface r12 to a fourteenth surface r14. This is a three-group type zoom lens having a decenterable lens formed by enclosing a liquid in a second lens group.

[0031]

[Table 3]

[0032]

[Table 4] FNO 1: 4.0 6.1 8.2 f 39.12 70.00 102.00 fB 8.80 28.93 49.20 ω 28.6 ° 16.8 ° 11.8 ° d6 3.50 11.03 14.56 d16 13.36 5.83 2.31

In the case of this embodiment, the whole lens system is 0.5 °
When tilted, 0.95 ° for a focal length of 39mm,
1.09 ° for 70 mm, 1.
By decentering the eccentric lenses by 17 °, the movement of the image can be corrected.

FIGS. 12, 13, and 14 are spot diagrams when the tilt of the entire system is corrected by the decenterable lens at the focal lengths of 39 mm, 70 mm, and 102 mm, respectively.
As in the case of the first embodiment, the three spot diagrams in each figure have an image height of 21.6 unless the lens system is tilted.
This figure shows the state of a light beam which forms an image at mm, 0 mm (incident angle 0 °), and -21.6 mm after falling.

[0035]

As described above, the decenterable lens according to the present invention uses a member which functions both as a lens and as a liquid, thereby making it possible to compare with a conventional variable apex prism in which a liquid is sealed between parallel plane plates. Then, the boundary surface of the medium can be reduced by two, and ghost and decrease in light amount due to reflection can be reduced. Furthermore, since the lens that encloses the liquid contributes to aberration correction and power in the optical system as an element having a lens function, the thickness in the optical axis direction must be smaller than that after simply forming a prism with a parallel plane plate. Can be.

Therefore, by using this decenterable prism, it is possible to provide a small-sized vibration compensation lens having good performance.

[Brief description of the drawings]

FIG. 1 is a lens diagram of a vibration compensation lens according to a first embodiment when no eccentricity occurs.

FIG. 2 is a diagram illustrating various aberrations of the vibration compensation lens according to the first exemplary embodiment when the lens is not decentered.

FIG. 3 is a lens diagram when the tilt of the vibration compensating lens according to the first embodiment is corrected by eccentricity.

FIG. 4 is a spot diagram when the tilt of the vibration compensation lens according to the first embodiment is corrected by eccentricity.

FIG. 5 is a lens diagram of the vibration compensation lens according to a second embodiment when there is no eccentricity.

FIG. 6 is a diagram illustrating various aberrations of the vibration compensation lens according to the second embodiment when no eccentricity occurs;

FIG. 7 is a spot diagram when the tilt of the vibration compensation lens according to the second embodiment is corrected by eccentricity.

FIG. 8 is a lens diagram of the vibration compensation zoom lens according to a third embodiment when there is no eccentricity.

FIG. 9 is a diagram illustrating various aberrations at a focal length of 39 mm when the vibration compensation zoom lens according to the third embodiment is not decentered.

FIG. 10 is a diagram illustrating various aberrations at a focal length of 70 mm without decentering of the vibration compensation zoom lens according to the third embodiment.

FIG. 11 is a diagram illustrating various aberrations at a focal length of 102 mm without decentering of the vibration compensation zoom lens according to the third embodiment.

FIG. 12 is a spot diagram at a focal length of 39 mm when the tilt of the vibration compensation zoom lens according to the first embodiment is corrected by eccentricity.

FIG. 13 is a spot diagram at a focal length of 70 mm when the tilt of the vibration compensation zoom lens according to the first embodiment is corrected by eccentricity.

FIG. 14 is a spot diagram at a focal length of 102 mm when the tilt of the vibration compensation zoom lens of the first embodiment is corrected by eccentricity.

Claims (2)

(57) [Claims] 1. An opposing surface of two lenses or a lens group is a plane, a sealed space is formed between the planes, a transparent liquid is sealed, and the optical axes of the two lenses or the lens groups are relatively adjusted by an external force. An eccentric lens, characterized in that the lens can be tilted to an angle. 2. An optical system comprising at least one set of eccentric lenses according to claim 1, comprising a plurality of lenses, and adjusting the relative tilt of the optical axis according to the tilt of the entire lens system. A vibration compensation lens system characterized by the above.