JP2001116989A - Objective with vibration-proofing function and binoculars using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an objective with a vibration-proofing function which corrects a blur of an image when the objective vibrates (at the time of a hand shake) while simplifying the mechanism and binoculars using the objective. SOLUTION: The objective has a 1st group with positive refracting power, a 2nd group with positive refracting power, a 3rd group with negative refracting power, and an erecting optical system which forms as an erect image an object image formed through the three lens groups in order the object side and one of the 1st, 2nd, and 3rd groups is moved at right angles to the optical axis to correct an image blur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens having a function of correcting a blur of an observed image due to camera shake or vibration proof, so-called vibration proof function, and binoculars using the same, and more particularly to an objective lens for vibration proof. Some of the movable lens groups are moved, for example, in a direction orthogonal to the optical axis to improve the anti-vibration effect and prevent deterioration of the optical performance when the optical axes of the left and right eyes are exerted. It can be observed in a state.

[0002]

2. Description of the Related Art Conventionally, various anti-vibration optical systems having a shake correcting means for correcting a shake of an observed image or a photographed image have been proposed.

For example, in Japanese Patent Application Laid-Open No. Hei 10-186228, in order from the object side, an objective composed of a first lens group having a positive refractive power, a second lens group having a negative refractive power, and an erecting prism system. A lens system and an eyepiece lens system having an overall positive refractive power for enlarging and viewing an erect image formed on the eye side of the erecting prism system by the objective lens system. An image stabilizing optical system that stabilizes an image by displacing an image by moving a lens group in a direction substantially orthogonal to an optical axis has been proposed.

Further, binoculars having an image stabilizing function have been proposed, for example, in Japanese Patent Application Laid-Open No. 55-99718.

In this publication, image blur is corrected by spatially stabilizing a prism suspended in the optical system by a gimbal frame by a gyro motor.

[0006]

Problems to be Solved by the Invention JP-A-10-18
The image stabilizing optical system proposed in Japanese Patent No. 6228 can perform image blur correction with a relatively simple configuration.

However, as an objective lens for binoculars, the Fno is as low as 6.5, and correction of high-order spherical aberration, lateral chromatic aberration, and axial chromatic aberration is not always sufficient when there is no image blur correction. In addition, the optical performance tends to deteriorate during image blur correction. Further, since the lateral magnification of the second group is as small as 2.5, the shift amount of the eccentric group when the ray deflection angle on the object side is 0.5 ° is as large as 1.513,
The value is larger than that of other anti-vibration lenses for photographic lenses.

In addition, the binoculars having an anti-vibration function proposed in Japanese Patent Application Laid-Open No. 55-99718 tend to increase the size and complexity of the entire apparatus because the prism is driven by a gyro motor. there were.

According to the present invention, the Fno is bright, has an anti-vibration function, realizes an improvement in basic optical performance when no anti-vibration is performed, and has a small deterioration in optical performance during anti-vibration operation. It is another object of the present invention to provide an objective lens having a small shift amount of an eccentric group in a certain lens configuration.

In addition, according to the present invention, the optical axis is adjusted by parallel eccentricity of a part of the lens groups constituting the objective lens, and the vibration is prevented by parallel eccentricity of another lens group. It is an object of the present invention to provide binoculars having the objective lens in which deterioration of optical performance is small at the time of parallel decentering of each lens group.

[0011]

The objective lens according to the first aspect of the present invention comprises, in order from the object side, a first group having a positive refractive power, a second group having a positive refractive power, and a third group having a negative refractive power. And an erecting optical system that turns an object image formed through the three lens groups into an erect erect image, wherein the first group, the second group,
It is characterized in that any one lens group of the third group is moved in a direction perpendicular to the optical axis to correct image blur.

A second aspect of the present invention is characterized in that, in the first aspect, each of the first, second, and third groups includes at least one positive lens and at least one negative lens. .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the first group is composed of one cemented lens cemented in order from the object side with a positive lens and a negative lens. And

According to a fourth aspect of the present invention, in the first aspect of the present invention, the second group includes, in order from the object side, two single lenses, a positive lens and a negative lens. And

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the third unit is a single cemented lens in which a positive lens and a negative lens are cemented in order from the object side. It is characterized by comprising.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the second lens unit includes, in order from the object side, one positive lens, a negative lens, and a positive lens. It is characterized by comprising one cemented lens.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the third unit is cemented in the order of a negative lens and a positive lens from the object side. One
It is characterized by consisting of two cemented lenses.

The invention of claim 8 is the invention according to any one of claims 1 to 7, wherein the focal length of the entire objective lens system is f and the focal length of the first group is f _1. It is characterized by satisfying a conditional expression of f ₁ /f<1.2.

According to a ninth aspect of the present invention, when the focal length of the entire objective lens system is f and the focal length of the second lens unit is f ₂ , 0.5 <0.5. It is characterized by satisfying a conditional expression of f ₂ /f<0.9.

In a tenth aspect of the present invention, when the focal length of the entire objective lens system is f and the focal length of the third group is f ₃ , 0.2 <0.2. | F ₃ /f|<0.6.

[0021] The invention of claim 11 in the invention of any one of 10 claims 1, the focal length of the objective lens system f, and the principal point interval between the first group and the second group was e ₁₂ It is characterized by satisfying 0.15 <conditional expression e ₁₂ /f<0.35 time.

[0022] The invention of claim 12 in the invention of any one of claims 1 to 11, the focal length of the objective lens system f, and the principal point interval between the second group and the third group was e ₂₃ It is characterized by satisfying the following condition: 0.1 <e ₂₃ /f<0.3.

According to a thirteenth aspect of the present invention, in the invention of any one of the first to twelfth aspects, the length from the first surface on the object side to the paraxial image plane when the length of the erecting optical system is converted to air is calculated. When the distance is L and the focal length of the entire objective lens system is f, the condition of L / f <0.9 is satisfied.

According to a fourteenth aspect, in the first aspect, the first group, the second group, and the third
The third-order spherical aberration coefficients of the group are denoted by I ₁ , I ₂ , I ₃ ,
The third-order coma aberration coefficients of the second and third groups are represented by II ₁ , II ₂ , II ₃
Where | I ₁ | <3 | II ₁ | <4 | I ₂ | <3 and | II ₂ | <4 | I ₃ | <3 | II ₃ | <4 I have.

According to a fifteenth aspect, in the first aspect, the first group includes a cemented lens of a positive lens and a negative lens, and the second group includes a positive lens and a negative lens. The third unit has a positive lens and a negative lens, the focal length of the i-th unit is fi, the focal length of the entire objective lens system is f, the principal point interval between the first and second units is e ₁₂ , and the second unit is when the third group of the main point interval time was _{e 23 0.8 <f 1 /f<1.2 0.5} <f 2 /f<0.9 0.2 <| f 3 / f | <0 0.6 0.15 <e ₁₂ /f<0.35 The condition that 0.1 <e ₂₃ /f<0.3 is satisfied.

According to a sixteenth aspect of the present invention, in the fifteenth aspect, the first, second, and second lens units are moved from the first lens surface of the first lens unit.
When the distance to the object image formed by the third lens unit (when the length of the erecting optical system is converted to air) is L, the conditional expression L / f <0.9 is satisfied. .

According to a seventeenth aspect of the present invention, there is provided a binocular according to any one of the first to sixteenth aspects, wherein a lens system comprising an objective lens having a vibration-proof function and an eyepiece having a positive refracting power is provided on the left and right sides of the viewer. It is characterized by having one pair for the eye.

[0028] According to an eighteenth aspect, in the seventeenth aspect, at least one of the first group, the second group, and the third group is moved in a direction perpendicular to the optical axis. ,
It is characterized in that the optical axes of the lens systems for the left and right eyes are adjusted.

A nineteenth aspect of the present invention is characterized in that, in the seventeenth aspect or the eighteenth aspect, the erecting optical system has an incident optical axis and an outgoing optical axis deviated.

A twentieth aspect is characterized in that, in the seventeenth, eighteenth, or nineteenth aspect, the erecting optical system comprises a Porro prism.

[0031]

FIG. 1 is a sectional view of a numerical example 1 of an objective lens according to the present invention. Objective lens OB of FIG.
Is composed of a first lens unit L having a positive refractive power in order from the object side.
1, a second unit L2 having a positive refractive power, a third unit L having a negative refractive power
3, and an erecting optical system P including a Porro prism and the like.

The first unit L1 includes a positive lens L11 from the object side,
The second lens unit includes one cemented lens cemented in the order of the negative lens L12, and the second lens unit includes a positive lens L21, a negative lens L
The third group includes one cemented lens cemented in order from the object side with a positive lens L31 and a negative lens L32. When correcting the image blur when the objective lens OB shakes the camera, the second unit is moved in a direction perpendicular to the optical axis. IP is an image plane, and an erect object image is formed.

The reason why the objective lens OB of this embodiment is constituted by a lens unit having positive, positive and negative refractive powers in order from the object side will be described. This will be described below in comparison.

FIGS. 13 (A) and 13 (B) show a three-group objective lens composed of a lens group having positive, positive and negative refractive power and a lens group having positive, negative and positive refractive power from the object side. It is a schematic diagram of a paraxial structure with a thin wall at the time.

In the lens system having positive, negative, and positive refractive powers shown in FIG. 13B, the area between the second group G2 and the third group G3 is close to afocal. Becomes longer, so that it is difficult to reduce the telephoto ratio. Further, if the telephoto ratio is reduced, the absolute value of the power of each group becomes large, so that the occurrence of aberration increases.

On the other hand, in the lens system having positive, positive and negative refractive powers shown in FIG. 13A, when the first unit G1 and the second unit G2 are considered as one positive lens, the third unit G3 is a negative lens. Because of this, it is a teletype, which is advantageous in that the overall length is shortened.

From the above, FIG.
It can be said that the lens system of (A) having positive, positive, and negative refractive power is advantageous.

Returning to FIG. 1, the first lens unit L1, the second lens unit L2, the third lens unit
The reason that each of the groups L3 is composed of one positive lens and one negative lens is that at least one positive lens and one negative lens are required for achromatism, and that each lens group is reduced in weight. is there.

The reason for arranging the first lens unit in the order of the positive lens and the negative lens from the object side is to make the object side principal point of the first lens unit as far as possible from the lens unit to the object side. Accordingly, the effective diameter of the lens on the image plane side of the first lens group is reduced, and the weight is reduced.

The reason for arranging the second lens unit in the order of the positive lens and the negative lens from the object side is to make the object-side principal point of the second lens unit as close as possible to the object side of the lens unit. Accordingly, the effective diameter of the lens on the image plane side of the second lens group is reduced, and the weight is reduced.

The reason for disposing the third lens unit in the order of the positive lens and the negative lens from the object side is that the object side principal point of the third lens unit is located as close to the object side as possible with respect to the lens unit. Accordingly, the effective diameter of the lens on the image plane side of the third lens group is reduced, and the weight is reduced.

When the image blur due to camera shake is corrected, the small-diameter and light-weight second unit is moved to reduce the size of an actuator (not shown) that operates the second lens unit.

FIG. 2 shows a numerical example 2 of the objective lens according to the present invention.
It is a lens sectional view of. In FIG. 2, a first unit L1 having a positive refractive power, a second unit L2 having a positive refractive power, a third unit L3 having a negative refractive power, and an erecting optical system P are arranged in this order from the object side.

The first unit L1 includes a positive lens L1 from the object side.
1. The second lens unit L2 is composed of one positive lens L from the object side.
The third lens unit L3 includes one cemented lens cemented in the order of a negative lens L31 and a positive lens L32 from the object side in the order of a negative lens L22 and a positive lens L23. It is made up of lenses.

To correct image blur caused by camera shake, the second lens unit is moved in a direction perpendicular to the optical axis.

The first group L1 and the third group L3 are each composed of one positive lens and one negative lens, and the second group is composed of two positive lenses and one negative lens. This is because at least one lens and one negative lens are required, and the weight of each lens group is reduced.

The reason for arranging the first lens unit in the order of the positive lens and the negative lens from the object side is that the object-side principal point of the first lens unit is located as close as possible to the object side of the lens unit. Thus, the effective diameter of the lens on the image side of the first lens group is reduced, and the weight is reduced.

The second group is composed of one positive lens from the object side, and one cemented lens which is cemented in the order of a negative lens and a positive lens. The object-side principal point is located closer to the object side than the second lens group, thereby reducing the effective diameter of the lens on the image side of the second lens group.

The third unit is composed of one positive lens and one negative lens for achromatization and weight reduction.

FIG. 3 shows a numerical example 3 of the objective lens according to the present invention.
It is a lens sectional view of. The lens configuration and the number of lenses of each group in this embodiment are the same as those in FIG.

FIG. 4 is a sectional view of a numerical example 4 of a lens system having an objective lens according to the present invention. The lens system shown in FIG. 4 includes the objective lens OB and the eyepiece EB shown in FIG. 1 having an image stabilizing function.

The eyepiece EB includes, in order from the incident side, one negative lens L41 concave on the incident side and having a stronger power on the incident side than the exit side, and one meniscus having a convex surface facing the exit side. Positive lens L42, a cemented lens L4 having a positive refractive power as a whole in a meniscus shape with the convex surface facing the exit side
3a, a positive lens L45, and a cemented lens L46a having a meniscus shape having a convex surface facing the incident side and having a positive refractive power as a whole.

The eyepiece EB has a positive refractive power as a whole. The cemented lens L43a is composed of a negative lens L43 with both lens surfaces concave, and a positive lens L44 with both lens surfaces convex.

The cemented lens L46a comprises a negative meniscus lens L46 having a convex surface facing the incident side and a positive lens L47 having a convex surface facing the incident side.

In this embodiment, an observation system for observing an erect object image formed by the objective lens OB with the eyepiece EB is constructed.

FIG. 5 is a sectional view of a main part of an optical system when a pair of the observation systems shown in FIG. 4 are applied to binoculars.

FIG. 7 shows a case where a Porro II prism is used as the erecting optical system P. In the figure, the objective lens O
The object image formed by the BJR (OBJL) is observed via the erecting optical system PR (PL) as an erect image via an eyepiece OCLR (OCLL) having a positive refractive power.

In FIG. 5, two right and left erecting optical systems P
R and PL are each composed of a Porro II prism formed by joining three right-angle prisms, and the optical axes O of two constantly fixed left and right objective lenses OBJR and OBJL.
The eye width adjustment is performed by rotating two right and left erect optical systems PR and PL and two right and left eyepieces OCLR and OCLL around AR and OAL (rotation centers CR and CL). Left and right two objective lenses OBJR,
By constantly fixing the optical axes OAR and OAL of the OBJL, a movable interlock mechanism (not shown) of the first group L1 and the second group L2 of the two left and right objective lenses is easily configured.

Further, by arranging the vertices A and B of the large right-angle prisms DPR, DPL of the two right and left erecting optical systems PR, PL so as to face each other, the erecting optical systems PR, P
As a whole, small binoculars with little protrusion of L are configured.

In the binoculars of this embodiment, at least one of the first group, the second group, and the third group of the two right and left objective lenses having a vibration reduction function is perpendicular to the optical axis. To adjust the left and right optical axes.

Further, in the binoculars, the erecting optical systems of the two right and left objective lenses having the image stabilizing function are different in the incident optical axis and the outgoing optical axis.

FIG. 6 is a longitudinal aberration diagram when the camera shake correction according to the first embodiment of the present invention is not performed. FIG. 7 is a longitudinal aberration diagram when the camera shake correction according to the second embodiment of the present invention is not performed. FIG. 8 is a longitudinal aberration diagram when the camera shake correction according to the third embodiment of the present invention is not performed. FIG. 9 is a longitudinal aberration diagram when the camera shake correction according to the fourth embodiment of the present invention is not performed.

FIGS. 10A and 10B show a comparison of lateral aberration diagrams at the center when each group of Numerical Embodiment 1 of the present invention is moved in a direction perpendicular to the optical axis. FIG. (B) when the first lens unit is decentered by 0.5 mm in parallel, (c) when the second lens unit is decentered by 0.5 mm, and (d) when the ray deflection angle on the object side is 0.3 °. (E) is the case where the third lens unit is parallel eccentrically 0.5 mm.

Here, the evaluation of the optical performance at the time of eccentricity of the first group is performed with the shift amount of the first group being 0.5 mm because the shift amount of the eccentric group at the time of optical axis adjustment is about 0.5 mm at the maximum. The reason why the optical performance of the second lens unit at the time of decentering is evaluated when the light beam deflection angle on the object side is 0.3 ° is that 90% of human hand shake is 0.1%. This is based on past experimental data that falls within 3 °.

FIGS. 11A and 11B show a comparison of the lateral aberration diagrams at the center when each group of Numerical Embodiment 2 is moved in a direction perpendicular to the optical axis. FIG. 11A shows a reference position, and FIG. (C) shows that the first lens unit is 0.5 mm in parallel when the first lens unit is decentered by 0.5 mm.
(D) when the second lens group is parallel eccentric when the ray deflection angle on the object side is 0.3 ° when the lens is parallel decentered by 5 mm; Is the case.

FIGS. 12A and 12B show a comparison of the lateral aberration diagrams at the center when each group of Numerical Embodiment 3 is moved in a direction perpendicular to the optical axis. FIG. 12A shows the reference position, and FIG. (C) shows that the first lens unit is 0.5 mm in parallel when the first lens unit is decentered by 0.5 mm.
(D) when the second lens group is parallel eccentric when the ray deflection angle on the object side is 0.3 ° when the lens is parallel decentered by 5 mm; Is the case.

The objective lens of the present invention and the binoculars using the objective lens are achieved by the above-described configuration, but it is more preferable that at least one of the following configurations is satisfied.

[0068] The conditional expression (a-1) the focal length of f of 0.8 and a focal length of the first group was _{f 1 <f 1 /f<1.2 ‥‥‥ (} 1) To be satisfied.

Conditional expression (1) represents the total system of the objective lens of the present invention.
Focal length f and the first group focal length f ₁Limited about the ratio of
In the region exceeding the lower limit of conditional expression (1),
The focal length of the first lens group is too short, and as a result
The occurrence of higher-order aberrations in the lens group is
In the region exceeding the upper limit, the positive
The axis that is too weak and is emitted from the first lens group
The convergence range of external rays is large, and the effective diameter of the second group is large.
It is not preferable because it becomes worse.

(A-2) Assuming that the focal length of the second lens unit is f ₂ , the conditional expression 0.5 <f ₂ /f<0.9‥‥‥(2) is satisfied.

Conditional expression (2) represents the total system of the objective lens of the present invention.
Focal length f and focal length f of the second group _TwoLimited about the ratio of
In the region exceeding the lower limit of conditional expression (2),
The focal length of the second lens group is too short, and as a result
The occurrence of higher-order aberrations in the lens group is
In the region exceeding the upper limit, the positive
Power is too weak, shift amount of the second group during vibration isolation
Is undesirably increased.

(A-3) Assuming that the focal length of the third lens unit is f ₃ , the following conditional expression is satisfied: 0.2 <| f ₃ /f|<0.6‥‥‥(3)

Conditional expression (3) represents the total system of the objective lens of the present invention.
Focal length f and focal length f of the third group _ThreeLimited about the ratio of
In the region exceeding the lower limit of conditional expression (3),
The power of the third lens group is increased and the lateral magnification of the third group is large.
And the aberrations generated in the first and second groups are large.
Because it is magnified by the ratio
Is increased, and in the region exceeding the upper limit,
The negative power of the third group is too weak, the second group at the time of anti-vibration operation
Is undesirably large.

(A-4) The distance between the principal points of the first and second lens units is e
_When it is set to ₁₂ , the conditional expression 0.15 <e ₁₂ /f<0.35 (4) is satisfied.

[0075] Conditional expression (4) and the focal length f of the objective lens of the present invention, which has a range for the ratio of the first group and the second group of the main point interval e _12, expression (4) In the area exceeding the lower limit, the effective diameter of the lens on the object side of the second lens group becomes large and the weight increases, and in the area exceeding the upper limit, the back focus becomes short and the erecting optical system is arranged. It is inconvenient to do so.

(A-5) The principal point interval between the second group and the third group is e
_{When 23} is satisfied, the following conditional expression is satisfied: 0.1 <e ₂₃ /f<0.3 (5)

[0077] and conditional expression (5) is the focal length f of the entire system of the objective lens of the present invention, which has a range for the ratio of the second group and the third group of the main point interval e _23, expression (5) In a region exceeding the lower limit, the effective diameter of the third lens group is increased, so that the weight of the entire objective lens is increased, and further, the shift amount of the second group during the camera shake correction operation is increased. Further, in a region exceeding the upper limit, the back focus becomes short, which is inconvenient for arranging the erecting optical system.

(A-6) When the length of the erecting optical system is converted into air, the distance from the first surface on the object side to the paraxial image plane is L, and the focal length of the entire system is f. /F<0.9‥‥‥(6)

Condition (6) limits the telephoto ratio of the objective lens according to the present invention. If the upper limit of condition (6) is exceeded, the total length is undesirably long.
It is desirable to satisfy

(A-7) The first group, the second group, and the third group
The third order spherical aberration coefficient is I₁, I_Two, I _Three, The first group, the second
Set the third-order coma aberration coefficient of the second and third groups to II₁, II_Two, II_ThreeToss
| I₁| <3 | II₁| <4 | I_Two| <3 and | II_Two| <4 | I_Three| <3 | II_Three| <4 ‥‥‥ (7).

Next, the meaning of conditional expression (7) will be described.

"Yoshiya Matsui's 3rd Optical System with Eccentricity"
The following is written in the “Theory of Next Aberration” (JOEM technical text).

A description will be given of the aberration generated by the parallel movement of an arbitrary element. As shown in FIG.
It is assumed that the element has been translated by a small amount _Eν .

The term added to the lateral aberration due to the eccentricity is expressed as follows.

[0085]

(Equation 1)

Α ′: angle between the optical axis of the paraxial ray of the object after passing through the final lens surface R: entrance pupil radius converted on the object-side principal plane φ _R : azimuth ω of _R : object point and object-side principal An angle formed by a straight line connecting the point H and the reference axis φω: azimuth N of ω: refractive index of the object field, and

[0087]

(Equation 2)

Is as follows.

I to V are third-order aberration coefficients, P is Petzval sum, and k is the number of elements. The above (ΔE)
_{From ν} to (IIE) _ν is an eccentric aberration coefficient representing the influence of eccentricity, and functions to express a defect of an image having the following contents.

(ΔE) _ν : prism action (lateral displacement of image) (VE1) _ν , (VE2) _ν : rotationally symmetric distortion (IIIE) _ν , (PE) _ν : rotationally asymmetric astigmatism, image plane tilt (IIE) _ν : rotationally asymmetric coma aberration also appearing on the axis As is apparent from the conditional expression (8), the amount of eccentricity E _ν is applied to the entire right side, so that the amount of aberration generated by eccentricity is proportional to E _ν .

Since the binoculars have a narrow angle of view, attention is paid particularly to the eccentric coma aberration at the center, and the magnitude of the absolute value of the eccentric coma aberration coefficient will be considered below.

The eccentric coma aberration coefficient (IIE) _ν can be summarized as follows.

[0093]

(Equation 3)

Here,

[0095]

(Equation 4)

And φ _ν is the power of the ν-th element, h _ν

[0097]

[Outside 1]

Are the incident height of the object paraxial ray and the incident height of the pupil paraxial ray at the ν element.

The following can be considered as conditions for reducing the absolute value of conditional expression (10).

I) The absolute values of the third-order aberration coefficients I and II in each group are small. Ii) α _ν , h _ν ,

[0101]

[Outside 2]

Since the absolute values of the expressions are small, the absolute values of the expression and the expression are both small.

The condition (ii) will be described. To reduce the absolute value of the equation, α _ν ,

[0104]

[Outside 3]

Considering that the absolute value of α ₂ , α ₂ , α ₂ ,

[0106]

[Outside 4]

When the absolute values of
The group's power becomes weaker and therefore h _Two,

[0108]

[Outside 5]

The absolute value of the eccentric coma coefficient of the second group can be reduced because the absolute value of the eccentric coma coefficient of the second group increases. Not necessarily.

In order to reduce the absolute value of the equation, h
_ν ,

[0111]

[Outside 6]

Considering that the absolute value of each is made smaller, since the lens configuration is positive, positive, and negative from the object side,
h ₂ ,

[0113]

[Outside 7]

When the absolute values of
The power of the group is increased, and therefore the possibility that the absolute value of the term of the eccentric coma aberration coefficient of the first group is increased is increased, and the possibility that the eccentric coma aberration coefficient of the first group is increased is increased.

From the above, it can be said that it is not easy to satisfy the conditional expression (ii).

The condition (i) will be described. From equation (10) for the eccentric coma aberration coefficient, it is considered that the absolute value of the eccentric coma aberration coefficient can be reduced by reducing the absolute values of the third-order aberration coefficients I and II of each group.

Here, according to the conditional expressions (1) to (3),
Since the power of each group cannot be made smaller than a certain value, the third-order aberration coefficients I and II cannot be made smaller than a certain value. The third-order aberration coefficients I and II have the following dependency.

II _ν = J · I _ν where the coefficient J is a value calculated from paraxial tracking. Therefore, if the absolute value of I is reduced, the absolute value of II is also reduced.

From the above, it can be seen that the third-order aberration coefficients I and II are desirably as small as possible to satisfy the conditional expression (7).

As described above, according to the present invention, the optical axis is adjusted by parallel eccentricity of a part of the lens groups constituting the objective lens, and is prevented by parallel eccentricity of another lens group. The binoculars having the objective lens can be achieved by performing the shaking and having a small deterioration in optical performance when the respective lens groups are decentered in parallel.

In addition, according to the present invention, it is possible to realize an objective lens having an image stabilizing function with little deterioration in optical performance at the time of camera shake correction. Further, with respect to binoculars composed of two left and right objective lenses and two right and left eyepieces having a positive refractive power, the left and right optical axes can be adjusted by decentering the first group of the objective lenses in parallel. Binoculars having a vibration reduction function that can perform camera shake correction by parallel eccentricity of the second lens group and have a small deterioration in optical performance when the first lens group and the second lens group are respectively eccentrically parallel. realizable.

Next, numerical examples will be shown. In the numerical examples, ri is the radius of curvature of the i-th surface in order from the object side, di
Is the distance between the i-th surface and the (i + 1) -th surface in order from the object side, and ni and νi are the refractive index and Abbe number of the glass of the i-th optical member in order from the object side. Tables below show the relationship between the above-described conditional expressions and various numerical values in the numerical examples.

(Numerical Example 1) f = 179.8 FNo = 4 2ω = 4.46 ° r 1 = 108.4486 d 1 = 7.32986 n 1 = 1.496999 ν 1 = 81.54 r 2 = -73.9573 d 2 = 1.9 n 2 = 1.60562 ν 2 = 43.7 r 3 = -245.613 d 3 = 51.26688 r 4 = 42.95312 d 4 = 4.97023 n 3 = 1.48749 ν 3 = 70.23 r 5 = -910.651 d 5 = 2.60075 r 6 = 34337.56 d 6 = 1.5 n 4 = 1.805181 ν 4 = 25.42 r 7 = 232.9455 d 7 = 16.17475 r 8 = -674.245 d 8 = 1.77953 n 5 = 1.805181 ν 5 = 25.42 r 9 = -117.823 d 9 = 1.2 n 6 = 1.603112 ν 6 = 60.64 r10 = 37.25163 d10 = 5.15564 r11 = ∞ d11 = 86 n 7 = 1.56883 ν 7 = 56.13 r12 = ∞ d12 = 9.97376 (Numerical Example 2) f = 179.9 FNo = 4 2ω = 4.46 ° r 1 = 108.223 d 1 = 7.55146 n 1 = 1.496999 ν 1 = 81.61 r 2 = -80.6476 d 2 = 3.50036 n 2 = 1.60562 ν 2 = 43.7 r 3 = -366.636 d 3 = 41.60088 r 4 = 54.19616 d 4 = 3.73477 n 3 = 1.72342 ν 3 = 37.95 r 5 = 167.0193 d 5 = 4.86855 r 6 = 41.19286 d 6 = 1.79573 n 4 = 1.784696 ν 4 = 26.29 r 7 = 26.82575 d 7 = 0 n 5 = 1.784696 ν 5 = 26.29 r 8 = 26.82575 d 8 = 3.06718 n 6 = 1.48749 ν 6 = 70. 21 r 9 = 41.62657 d 9 = 19.41166 r10 = 379.7065 d10 = 1.44791 n 7 = 1.72342 ν 7 = 37.95 r11 = 28.46757 d11 = 0 n 8 = 1.72342 ν 8 = 37.95 r12 = 28.46757 d12 = 3.10218 n 9 = 1.846659 ν 9 = 23.78 r13 = 43.8268 d13 = 3.83406 r14 = ∞ d14 = 86 n10 = 1.56883 ν10 = 56.13 r15 = ∞ d15 = 10.01153 (Numerical Example 3) f = 179.9 FNo = 4 2ω = 4.46 ° r 1 = 111.1579 d 1 = 7.89938 n 1 = 1.496999 ν 1 = 81.61 r 2 = -67.5968 d 2 = 3.49967 n 2 = 1.548141 ν 2 = 45.79 r 3 = -462.294 d 3 = 40.09574 r 4 = 52.58082 d 4 = 3.81355 n 3 = 1.72342 ν 3 = 37.95 r 5 = 145.0381 d 5 = 5.03602 r 6 = 41.33485 d 6 = 2.13453 n 4 = 1.784696 ν 4 = 26.29 r 7 = 27.12508 d 7 = 0 n 5 = 1.784696 ν 5 = 26.29 r 8 = 27.12517 d 8 = 3.01831 n 6 = 1.48749 ν 6 = 70.21 r 9 = 41.72931 d 9 = 19.39628 r10 = 332.4285 d10 = 1.29003 n 7 = 1.72342 ν 7 = 37.95 r11 = 27.91964 d11 = 0 n 8 = 1.72342 ν 8 = 37.95 r12 = 27.91964 d12 = 2.16198 n 9 = 1.846659 ν 9 = 23.78 r13 = 43.44738 d13 = 3.35805 r14 = ∞ d14 = 86 n10 = 1.56883 ν10 = 56.13 r15 = ∞ d15 = 11.45665 (Numerical example 4) Magnification 15.0 2ω = 4.46 ° r 1 = 108.4486 d 1 = 7.32986 n 1 = 1.496999 ν 1 = 81.54 r 2 = -73.9573 d 2 = 1.9 n 2 = 1.60562 ν 2 = 43.7 r 3 = -245.613 d 3 = 51.26688 r 4 = 42.95312 d 4 = 4.97023 n 3 = 1.48749 ν 3 = 70.23 r 5 = -910.651 d 5 = 2.60075 r 6 = 34337.56 d 6 = 1.5 n 4 = 1.805181 ν 4 = 25.42 r 7 = 232.9455 d 7 = 16.17475 r 8 = -674.245 d 8 = 1.77953 n 5 = 1.805181 ν 5 = 25.42 r 9 = -117.823 d 9 = 1.2 n 6 = 1.603112 ν 6 = 60.64 r10 = 37.25163 d10 = 2.87432 r11 = ∞ d11 = 86 n 7 = 1.56883 ν 7 = 56.13 r12 = ∞ d12 = 4.37 r13 = -11.155 d13 = 1.2 n 8 = 1.517417 ν 8 = 52.41 r14 = 78.48 d14 = 1.88 r15 = -20.766 d15 = 4 n 9 = 1.834 ν 9 = 37.17 r16 = −11.973 d16 = 12.5 r17 = -23.27 d17 = 1.5 n10 = 1.805181 ν10 = 25.43 r18 = 35.239 d18 = 12.4 n11 = 1.622992 ν11 = 58.15 r19 = -19.307 d19 = 0.2 r20 = 44.9 d20 = 7.75 n12 = 1.622992 ν12 = 58.15 r21 =- 44.9 d21 = 0.2 r22 = 23.968 d22 = 1.5 n13 = 1.728249 ν13 = 28.46 r23 = 13.424 d23 = 7.7 n14 = 1.622992 ν14 = 58.15 r24 = 78.226 d24 = 15 (eye relief)

[0124]

[Table 1]

[0125]

[Table 2]

[0126]

[Table 3]

[0127]

[Table 4]

[0128]

According to the present invention, the Fno is bright, has an anti-vibration function, improves the basic optical performance when the anti-vibration is not performed, and degrades the optical performance during the anti-vibration operation. In addition, an objective lens with a small shift amount of the eccentric group can be achieved with a certain lens configuration.

[Brief description of the drawings]

FIG. 1 is a sectional view of a numerical example 1 of an objective lens according to the present invention.

FIG. 2 is a sectional view of a numerical example 2 of the objective lens according to the present invention;

FIG. 3 is a sectional view of a numerical example 3 of the objective lens according to the present invention;

FIG. 4 is a sectional view of a numerical example 4 of the objective lens according to the present invention;

FIG. 5 is an explanatory diagram of a lens shape when a Porro II prism according to Numerical Example 4 of the present invention is inserted.

FIG. 6 is a longitudinal aberration diagram when the camera shake correction according to Numerical Embodiment 1 of the present invention is not performed.

FIG. 7 is a longitudinal aberration diagram when camera shake correction is not activated in Numerical Example 2 of the present invention.

FIG. 8 is a longitudinal aberration diagram when the camera shake correction according to Numerical Embodiment 3 of the present invention is not performed.

FIG. 9 is a longitudinal aberration diagram when camera shake correction is not activated in Numerical Example 4 of the present invention.

FIG. 10 is a lateral aberration comparison diagram on the optical axis when the optical axis is adjusted and when camera shake is corrected according to Numerical Embodiment 1 of the present invention.

FIG. 11 is a comparison diagram of lateral aberration on the optical axis when the optical axis is adjusted and when camera shake is corrected according to Numerical Example 2 of the present invention.

FIG. 12 is a diagram illustrating a comparison of lateral aberrations on the optical axis when the optical axis is adjusted and when camera shake is corrected according to Numerical Embodiment 3 of the present invention.

FIG. 13 is an explanatory diagram of a refractive power arrangement of the objective lens of the present invention.

FIG. 14 is an explanatory diagram of the optical principle of the vibration proof optical system according to the present invention.

[Explanation of symbols]

 L1 First group of objective lens L2 Second group of objective lens L3 Third group of objective lens P Expanded erecting optical system 4 Eyepiece OBJR Right objective lens group OBJL Left objective lens group PR Polo II for right Prism PL Porro II prism for left OCLR Right eyepiece group OCLL Left eyepiece group OAR Optical axis of right objective lens group OAL Optical axis of left objective lens group DPR Right roof prism DPL Left roof prism IP Image plane OB Objective lens EB eyepiece

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H039 AA05 AB16 AB22 AB32 2H087 KA16 LA01 LA11 NA07 PA04 PA05 PA19 PA20 PB06 PB07 QA02 QA03 QA06 QA14 QA19 QA21 QA22 QA25 QA26 QA32 QA39 QA41 QA42 QA45 QA46 RA

Claims (20)

[Claims] A first group having a positive refractive power, in order from the object side;
An objective lens comprising: a second group having a positive refractive power, a third group having a negative refractive power, and an erecting optical system that turns an object image formed through the three lens groups into an erect image. An objective lens having an image stabilizing function, wherein one of the first group, the second group, and the third group is moved in a direction perpendicular to the optical axis to correct image blur. . 2. An object having an anti-vibration function according to claim 1, wherein each of the first, second, and third groups includes at least one positive lens and at least one negative lens. lens. 3. The anti-vibration function according to claim 1, wherein the first group includes one cemented lens in which a positive lens and a negative lens are cemented in order from the object side. Objective lens. 4. The anti-vibration function according to claim 1, wherein the second group includes two single lenses, a positive lens and a negative lens, in order from the object side. Objective lens. 5. The third lens unit according to claim 1, wherein the third lens unit includes one cemented lens in which a positive lens and a negative lens are cemented in order from the object side. Objective lens with anti-vibration function. 6. The apparatus according to claim 1, wherein the second group includes, in order from the object side, one positive lens, and one cemented lens cemented in the order of a negative lens and a positive lens. 3
An objective lens having the anti-vibration function according to any one of the above. 7. The third lens unit according to claim 1, wherein the third lens unit includes a cemented lens in which a negative lens and a positive lens are cemented in this order from the object side. Objective lens with anti-vibration function. 8. The focal length of the entire objective lens system is f,
Let the focal length of one group be f ₁0.8 <f₁8. The method according to claim 1, wherein the following conditional expression is satisfied.
An objective lens having the anti-vibration function according to any one of the above. 9. The focal length of the whole objective lens system is f,
Let the focal length of the two groups be f _Two0.5 <f_Two9. The method according to claim 1, wherein the following conditional expression is satisfied.
An objective lens having the anti-vibration function according to any one of the above. 10. When the focal length of the entire objective lens system is f and the focal length of the third group is f ₃ , the following conditional expression is satisfied: 0.2 <| f ₃ /f|<0.6. An objective lens having a vibration-proofing function according to any one of claims 1 to 9. 11. The conditional expression 0.15 <e ₁₂ /f<0.35 is satisfied, where f is the focal length of the entire objective lens system, and e ₁₂ is the distance between the principal points of the first and second groups. 11. The method according to claim 1, wherein
An objective lens having the anti-vibration function according to any one of the above. 12. The conditional expression 0.1 <e ₂₃ /f<0.3 is satisfied, where f is the focal length of the entire objective lens system, and e ₂₃ is the distance between the principal points of the second and third groups. 12. The method according to claim 1, wherein
An objective lens having the anti-vibration function according to any one of the above. 13. The distance from the object-side first surface to the paraxial image plane when the length of the erecting optical system is converted to air is L, and the focal length of the entire objective lens system is f. 13. The condition of f <0.9 is satisfied.
An objective lens having the anti-vibration function according to any one of the above. 14. The third-order spherical aberration coefficients of the _first , _second , and third groups are I ₁ , I ₂ , and I ₃ , and the third-order spherical aberration coefficients of the _first , _second , and third groups are three. when the coma aberration coefficient and _{II 1, II 2, II 3} , | I 1 | <3 | II 1 | <4 | I 2 | <3 , and _{| II 2 | <4 | I} 3 | <3 | II 3 | <4, wherein the condition: | <4 is satisfied.
An objective lens having the anti-vibration function according to any one of the above. 15. The first group comprises a cemented lens of a positive lens and a negative lens, the second group has a positive lens and a negative lens, and the third group has a positive lens and a negative lens. And
The focal length of the i-th group is fi, the focal length of the entire objective lens system is f, the distance between the principal points of the first and second groups is e ₁₂ , and the distance between the principal points of the second and third groups is e ₂₃ . when _{0.8 <f 1 /f<1.2 0.5 <f} 2 /f<0.9 0.2 <| f 3 /f|<0.6 0.15 <e 12 / f <0. 2. The objective lens having an image stabilizing function according to claim 1, wherein the objective lens satisfies the following conditional expression: 35 0.1 <e ₂₃ /f<0.3. 16. The distance from the first lens surface of the first group to the object image formed by the first, second, and third groups (when the length of the erecting optical system is converted to air) 16. The objective lens having an anti-vibration function according to claim 15, wherein the conditional expression L / f <0.9 is satisfied. 17. A pair of lens systems each comprising an objective lens having a vibration reduction function according to any one of claims 1 to 16 and an eyepiece having a positive refractive power are provided for left and right eyes of an observer. Binoculars characterized by the following. 18. The optical axis adjustment of the left and right lens systems by moving at least one of the first group, the second group, and the third group in a direction perpendicular to the optical axis. 18. The binoculars according to claim 17, wherein: 19. The binoculars according to claim 17, wherein the erecting optical system has an incident optical axis and an outgoing optical axis which are shifted from each other. 20. Binoculars according to claim 17, 18 or 19, wherein said erecting optical system comprises a Porro prism.