JP2021128310A - Observation optical system and observation device - Google Patents

Abstract

To provide a compact observation optical system with an anti-shake function.SOLUTION: An observation optical system is provided, comprising an objective optical system, an erecting optical system for turning an object image formed by the objective optical system into an erect image, and an ocular optical system arranged in order from the object side to the image side. The objective optical system comprises, in order from the object side to the image side, a first lens group L1f having positive refractive power and a second lens group L2 having negative refractive power. The second lens group consists of one negative lens, or one negative lens and one positive lens. The second lens group is moved relative to an optical axis of the objective optical system to provide an anti-shake function. The observation optical system satisfies a condition expressed as: 0.03≤-f2/f0≤0.24, where f0 represents a focal length of the objective optical system and f2 represents a focal length of the second lens group L2.SELECTED DRAWING: Figure 1

Description

The present invention relates to an observation optical system suitable for an observation device such as binoculars and a telescope.

When observing an object through an observation optical system, the higher the magnification of the optical system, the greater the image shake due to the user's camera shake. Patent Document 1 is an observation optical system in which an object image formed by an objective lens is made into an erect image by an erecting prism, and the erect image is magnified and observed through an eyepiece. An observation optical system having an anti-vibration function for moving a group is disclosed.

Japanese Unexamined Patent Publication No. 2016-166907

However, in the observation optical system of Patent Document 1, the refractive power of the anti-vibration lens group is weak and its size is large. Therefore, not only is it disadvantageous in reducing the size of the observation optical system, but also the mechanism for driving the anti-vibration lens group becomes large and the power consumption increases.

The present invention provides a small observation optical system having an anti-vibration function and an observation device having the same.

The observation optical system as one aspect of the present invention includes an objective optical system arranged in order from the object side to the image side, an erect optical system that makes an object image formed by the objective optical system an erect image, and an eyepiece. It has an optical system. The objective optical system has a first lens group having a positive refractive power and a second lens group having a negative refractive power in this order from the object side to the image side. The second lens group is composed of one negative lens or one negative lens and one positive lens. Vibration isolation is performed by moving the second lens group with respect to the optical axis of the objective optical system. When the focal length of the objective optical system is f0 and the focal length of the second lens group L2 is f2,
0.03 ≦ −f2 / f0 ≦ 0.24
It is characterized by satisfying the above conditions.

An observation device having the above observation optical system also constitutes another aspect of the present invention.

According to the present invention, it is possible to realize a small observation optical system having an anti-vibration function.

FIG. 3 is a cross-sectional view of the observation optical system of the first embodiment. FIG. 5 is a longitudinal aberration diagram of the observation optical system of Example 1 when vibration isolation is not performed. FIG. 5 is a lateral aberration diagram of the observation optical system of Example 1 when vibration isolation is not performed. FIG. 3 is a lateral aberration diagram of the observation optical system of Example 1 at the time of vibration isolation. FIG. 5 is a cross-sectional view of the observation optical system of the second embodiment. FIG. 5 is a longitudinal aberration diagram of the observation optical system of Example 2 when vibration isolation is not performed. FIG. 5 is a lateral aberration diagram of the observation optical system of Example 2 when vibration isolation is not performed. FIG. 3 is a lateral aberration diagram of the observation optical system of Example 2 at the time of vibration isolation. FIG. 3 is a cross-sectional view of the observation optical system of Example 3. FIG. 3 is a longitudinal aberration diagram of the observation optical system of Example 3 when vibration isolation is not performed. FIG. 3 is a lateral aberration diagram of the observation optical system of Example 3 when vibration isolation is not performed. FIG. 3 is a lateral aberration diagram of the observation optical system of Example 3 at the time of vibration isolation. The figure which shows the binoculars provided with the observation optical system of Examples 1-3.

Hereinafter, examples of the present invention will be described with reference to the drawings. First, prior to the description of specific examples, items common to each embodiment will be described using the observation optical system of Example 1 shown in FIG.

The observation optical systems of each embodiment are an objective optical system arranged in order from the object side to the observation side (image side), and an erect prism (upright) having an object image formed by the objective optical system as an erect image. It has an optical system) and an eyepiece optical system. By using an observation optical system having this configuration, an object image can be observed as an upright image. The IP in the figure is an eye point, and the object image can be observed by locating the observer's eye here.

The objective optical system has a first lens group L1 having a positive refractive power and a second lens group L2 having a negative refractive power in this order from the object side to the observation side. When the user's camera shake occurs, the image shake is reduced (corrected), that is, prevented by moving (shifting) the second lens group L2 in the direction orthogonal to the optical axis of the objective optical system (that is, the observation optical system). You can shake. By configuring the objective optical system in this way, it is possible to realize an anti-vibration function with a simple and compact configuration.

The second lens group L2 as the anti-vibration lens group is composed of one negative lens or two lenses, one negative lens and one positive lens. With this configuration, the anti-vibration lens group can be made smaller and lighter, and good optical performance can be maintained even at the time of anti-vibration.

In the observation optical system of each embodiment, when the focal length of the objective optical system is f0 and the focal length of the second lens group L2 is f2,
0.03 ≦ −f2 / f0 ≦ 0.24 (1)
Satisfy the conditions. When −f2 / f0 exceeds the upper limit of the conditional expression (1), the refractive power of the second lens group L2 becomes too weak and the second lens group L2 becomes large or the amount of movement (shift amount) for vibration isolation. Is not preferable because it increases. If −f2 / f0 is less than the lower limit of the conditional expression (1), the refractive power of the second lens group L2 becomes too strong and the optical performance at the time of vibration isolation deteriorates, which is not preferable.

It is more preferable to set the numerical range of the conditional expression (1) as follows.
0.04 ≦ −f2 / f0 ≦ 0.23 (1a)
Further, it is more preferable to set the numerical range of the conditional expression (1) as follows.
0.05 ≦ −f2 / f0 ≦ 0.22 (1b)
The observation optical system of each embodiment preferably satisfies at least one of the following conditional expressions (2) to (5) in addition to the above-mentioned conditional expression (1).

In the observation optical system of each embodiment, the distance on the optical axis from the surface on the most object side in the objective optical system to the surface on the most object side of the erecting prism is d0, and the distance on the optical axis is from the surface on the most observation side of the second lens group L2. When the distance on the optical axis to the surface of the upright prism on the most object side is d02,
0.020 ≦ d02 / d0 ≦ 0.220 (2)
It is preferable to satisfy the above conditions. If d02 / d0 exceeds the upper limit of the conditional expression (2), the distance between the second lens group L2 and the upright prism becomes too long, and the second lens group L2 becomes large, which is not preferable. If d02 / d0 is less than the lower limit of the conditional expression (2), the distance between the second lens group L2 and the upright prism may become too close and they may interfere with each other, which is not preferable.

In the observation optical system of each embodiment, when the thickness of the second lens group L2 on the optical axis is t2,
0.010 ≦ t2 / d0 ≦ 0.110 (3)
It is desirable to satisfy the above conditions. When t2 / d0 exceeds the upper limit of the conditional expression (3), the thickness of the second lens group L2 becomes too thick and the weight of the second lens group L2 increases, so that the second lens group L2 is driven during vibration isolation. Is not preferable because it makes it difficult. If t2 / d0 is less than the lower limit of the conditional expression (3), the thickness of the second lens group L2 becomes too thin, which makes it difficult to manufacture the second lens group L2, which is not preferable.

In the observation optical system of each embodiment, when the lateral magnification of the second lens group L2 is β2,
1.0 ≤ β2 ≤ 5.5 (4)
It is preferable to satisfy the above conditions. If β2 exceeds the upper limit of the conditional expression (4), the refractive power of the second lens group L2 becomes too strong and the optical performance at the time of vibration isolation deteriorates, which is not preferable. Further, when β2 falls below the lower limit of the conditional expression (4), the refractive power of the second lens group L2 becomes too weak, the second lens group L2 becomes larger, and the shift amount at the time of vibration isolation increases. , Not preferable.

When the focal length of the eyepiece optical system is fe, the observation optical system of each embodiment is used.
9.0 ≤ f0 / fe ≤ 31.0 (5)
It is preferable to satisfy the above conditions. If f0 / fe exceeds the upper limit of the conditional expression (5), the magnification (observation magnification) of the observation optical system becomes too high, making it difficult to observe the object, which is not preferable. If f0 / fe is less than the lower limit of the conditional expression (5), the observation magnification of the observation optical system becomes too low and the necessity of the vibration isolation function itself diminishes, which is not preferable.

It is more preferable to set the numerical range of the conditional expressions (2) to (5) as follows.
0.025 ≦ d02 / d0 ≦ 0.215 (2a)
0.013 ≤ t2 / d0 ≤ 0.100 (3a)
1.4 ≤ β2 ≤ 5.2 (4a)
9.5 ≤ f0 / fe ≤ 30.0 (5a)
Further, it is more preferable to set the numerical range of the conditional expressions (2) to (5) as follows.
0.030 ≦ d02 / d0 ≦ 0.210 (2b)
0.015 ≤ t2 / d0 ≤ 0.090 (3b)
1.8 ≤ β2 ≤ 5.0 (4b)
10.0 ≦ f0 / fe ≦ 29.0 (5b)
Further, in the observation optical system of each embodiment, the first lens group L1 includes a lens group (normal lens group) L1f having a positive refractive power, and the positive lens group L1f is moved in the optical axis direction for focusing. With this configuration, the focus function can be realized with a simple configuration.

Hereinafter, specific examples (numerical examples) 1 to 3 of the present invention will be described.

FIG. 1 shows the configuration of the observation optical system of Example 1 (Numerical Example 1). The details of the configuration are as described above, and the second lens group L2 is composed of a junction lens of one positive lens and one negative lens. The observation optical system of this embodiment is an observation optical system having an observation magnification of about 20.0 times, a pupil diameter of about 2.5 mm, and a half angle of view of about 1.8 °.

FIG. 2 shows spherical aberration, astigmatism, distortion, and chromatic aberration, which are longitudinal aberrations when the observation optical system of this embodiment is non-vibration-proof (when the center of the second lens group L2 is located on the optical axis). .. In the spherical aberration, the solid line shows the spherical aberration with respect to the d line, and the two-point chain line shows the spherical aberration with respect to the g line. In the astigmatism, the broken line indicates the astigmatism on the meridional image plane, and the solid line indicates the astigmatism on the sagittal image plane. The distortion is for the d line. The chromatic aberration shows the chromatic aberration of magnification with respect to the g-line.

3 and 4 show vibration isolation of the observation optical system of this embodiment during non-vibration isolation and vibration isolation (when the second lens group L2 is shifted by +1.938 mm to perform vibration isolation with a correction angle of 1.0 °, respectively. ) Indicates the lateral aberration for each angle of view. When the half angle of view is ω, each figure shows + 100% (ω = 1.8 °), + 50% (ω = 0.9 °), center (ω = 0 °), and -50% (ω) in order from the top. It shows the lateral aberration with respect to the d line at the angle of view of −0.9 °) and −100% (ω = -1.8 °). The broken line shows the lateral aberration on the sagittal image plane, and the solid line shows the lateral aberration on the meridional image plane. The description of the longitudinal aberration diagram and the transverse aberration diagram is the same in Examples 2 and 3 described later except for the shift amount of the second lens group L2 at the time of vibration isolation.

Specific numerical values of the observation optical systems of this example and Examples 2 and 3 are summarized below.

FIG. 2 shows the configuration of the observation optical system of Example 2 (Numerical Example 2). The details of the configuration are as described above, and the second lens group L2 is composed of a junction lens of one positive lens and one negative lens. The observation optical system of this embodiment is an observation optical system having an observation magnification of about 15.0 times, a pupil diameter of about 3.33 mm, and a half angle of view of about 2.4 °.

FIG. 6 shows the longitudinal aberration of the observation optical system of this embodiment when it is not vibration-proof. 7 and 8 show a correction angle of 1.0 ° by shifting the observation optical system of this embodiment by +1.862 mm in the direction orthogonal to the optical axis when the observation optical system is non-vibration-proof and vibration-proof (the second lens group L2 is shifted by +1.862 mm in the direction orthogonal to the optical axis, respectively. The lateral aberration for each angle of view at (when vibration isolation is performed) is shown.

FIG. 9 shows the configuration of the observation optical system of Example 3 (Numerical Example 3). The details of the configuration are as described above, and the second lens group L2 is composed of one negative lens. The observation optical system of this embodiment is an observation optical system having an observation magnification of about 12.0 times, a pupil diameter of about 4.18 mm, and a half angle of view of about 2.9 °.

FIG. 10 shows the longitudinal aberration of the observation optical system of this embodiment when it is not vibration-proof. 11 and 12 show vibration isolation of the observation optical system of this embodiment during non-vibration isolation and vibration isolation (when the second lens group L2 is shifted by +1.883 mm to perform vibration isolation with a correction angle of 1.0 °, respectively. ) Indicates the lateral aberration for each angle of view.

Numerical examples 1 to 3 are shown below. In each numerical example, ri is the radius of curvature (mm) of the i-th surface from the object side, di is the lens thickness or air spacing (mm) between the i-th and (i + 1) -th surfaces, and ndi is the i-th optical. The refractive index of the material of the member (lens and prism) at line d. νdi is an Abbe number based on the d-line of the material of the i-th optical member.

The Abbe number νd is when the refractive indexes of the Fraunhofer line d line (587.6 nm), F line (486.1 nm), and C line (656.3 nm) are Nd, NF, and NC.
νd = (Nd-1) / (NF-NC)
It is represented by.

The "*" attached to the surface number means that the surface has an aspherical shape. For the aspherical shape, the optical axis direction is the X axis, the direction orthogonal to the optical axis is the H axis, the light traveling direction is positive, R is the paraxial radius of curvature, K is the conical constant, and A4, A6, A8, and A10 are. When it is an aspherical coefficient, it is expressed by the following formula. ^{The aspherical coefficient "ex} " means 10-x.

(Numerical example 1)
Unit mm

Surface data Surface number rd nd ν d
1 44.966 9.75 1.49700 81.5
2 -645.511 17.86
3 46.689 7.42 1.43875 94.9
4-59.386 2.70 1.80400 46.6
5 75.307 27.85
6 27.167 2.66 1.48749 70.2
7 72.012 6.17
8-54.278 3.88 1.77250 49.6
9 -18.417 1.50 1.64000 60.1
10 21.646 6.79
11 ∞ 37.70 1.65844 50.9
12 ∞ 37.70 1.65844 50.9
13 ∞ 5.25
14 * -9.489 2.12 1.53160 55.8
15 27.611 1.07
16 49.112 7.97 1.84666 23.8
17 -22.630 14.68
18 -103.919 2.00 1.84666 23.8
19 20.323 13.16 1.65160 58.5
20 -33.475 1.00
21 40.835 5.24 1.77250 49.6
22 -211.685 0.29
23 32.252 5.30 1.60311 60.6
24 ∞ 20.00

14th surface of aspherical data
K = 0.00000e + 000 A 4 = 1.53388e-004 A 6 = 2.72143e-006 A 8 = -4.55814e-008 A10 = 5.42766e-010

Various data Objective optical system Start surface 1 End surface 10
Upright prism start surface 11 end surface 13
Eyepiece optical system Start surface 14 End surface 24
1st lens group L1 Start surface 1 End surface 7
Lens group L1f Start surface 6 End surface 7
2nd lens group L2 Start surface 8 End surface 10

(Numerical example 2)
Unit mm

Surface data Surface number rd nd ν d
1 44.506 10.21 1.49700 81.5
2 -342.333 13.71
3 56.382 7.51 1.43875 94.9
4-58.189 2.70 1.80400 46.6
5 109.473 16.57
6 36.841 3.47 1.48749 70.2
7 104.510 6.47
8-67.921 2.43 1.77250 49.6
9 -24.593 1.50 1.64000 60.1
10 28.917 10.13
11 ∞ 42.00 1.65844 50.9
12 ∞ 42.00 1.65844 50.9
13 ∞ 5.80
14 * -10.400 2.12 1.53160 55.8
15 30.857 2.43
16 453.338 10.26 1.84666 23.8
17 -18.743 13.45
18 -178.240 2.00 1.84666 23.8
19 25.953 13.27 1.69680 55.5
20 -37.800 1.00
21 39.700 5.41 1.60311 60.6
22 -378.542 0.29
23 33.731 5.30 1.48749 70.2
24 ∞ 20.00

14th surface of aspherical data
K = 0.00000e + 000 A 4 = 1.03277e-004 A 6 = 1.85689e-006 A 8 = -2.83912e-008 A10 = 2.50449e-010

Various data Objective optical system Start surface 1 End surface 10
Upright prism start surface 11 end surface 13
Eyepiece optical system Start surface 14 End surface 24
1st lens group L1 Start surface 1 End surface 7
Lens group L1f Start surface 6 End surface 7
2nd lens group L2 Start surface 8 End surface 10

(Numerical example 3)
Unit mm

Surface data Surface number rd nd ν d
1 42.953 10.32 1.49700 81.5
2 -509.782 13.23
3 41.042 9.13 1.43875 94.9
4-63.321 2.70 1.80400 46.6
5 91.372 8.25
6 38.122 2.27 1.48749 70.2
7 52.304 6.32
8-2466.075 1.50 1.64000 60.1
9 26.334 10.49
10 300.000 1.50 1.48749 70.2
11 ∞ 1.50
12 ∞ 43.60 1.65844 50.9
13 ∞ 43.60 1.65844 50.9
14 ∞ 5.12
15 * -11.511 2.12 1.53160 55.8
16 30.000 1.71
17 96.659 8.75 1.84666 23.8
18 -20.514 12.46
19 -58.504 2.00 1.84666 23.8
20 30.661 14.61 1.69680 55.5
21 -27.837 1.00
22 37.656 8.21 1.60311 60.6
23 -225.736 0.29
24 49.786 5.30 1.48749 70.2
25 ∞ 20.00

15th surface of aspherical data
K = 0.00000e + 000 A 4 = 1.56384e-004 A 6 = -1.46641e-007 A 8 = 4.27699e-009 A10 = 1.91538e-011

Various data Objective optical system Start surface 1 End surface 11
Upright prism start surface 12 end surface 14
Eyepiece optical system Start surface 15 End surface 25
1st lens group L1 Start surface 1 End surface 7
Lens group L1f Start surface 6 End surface 7
2nd lens group L2 Start surface 8 End surface 9

Table 1 summarizes the numerical values of the conditional expressions (1) to (5) in each embodiment (numerical example).

FIG. 13 shows binoculars as an observation device using the observation optical system of Examples 1 to 3. In FIG. 13, each reference numeral corresponds to the reference numeral in FIG.

In FIG. 13, 1R is an observation optical system for the right eye, and 1L is an observation optical system for the left eye. The runout sensor 1 is a vibration gyro or the like, and includes a pitch runout sensor that detects vertical runout and a yaw runout sensor that detects horizontal runout. The sensitivity axes of these two runout sensors are orthogonal to each other. The runout sensor 1 detects the runout (angular acceleration) of the binoculars and outputs the information to the microcomputer 2. The microcomputer 2 calculates the driving amount of the second lens group L2 for vibration correction based on the information of the angular acceleration, and outputs it to the lens actuator 3. The lens actuator 3 translates the second lens group L2 in a direction orthogonal to the optical axis or rotates around a point on the optical axis according to the amount of drive from the microcomputer 2. The position sensor 4 detects the position of the second lens group L2 and outputs the result to the microcomputer 2. When the detected position matches the position corresponding to the driving amount obtained by the calculation, the microcomputer 2 stops the driving of the second lens group L2 by the lens actuator 3. As a result, image shake caused by the shake of the binoculars is reduced.

By using the observation optical systems of Examples 1 to 3 in this way, it is possible to realize binoculars that are compact and have good optical performance even at the time of vibration isolation.

The observation optical systems of Examples 1 to 3 can be used not only for binoculars but also for various observation devices such as a telescope and an optical finder for a camera.

Each of the above-described examples is only a representative example, and various modifications and changes can be made to each of the examples in carrying out the present invention.

L1 1st lens group L1f Positive lens group L2 2nd lens group IP eye point

Claims (7)

An observation optical system having an objective optical system arranged in order from the object side to the image side, an erect optical system for making an object image formed by the objective optical system an erect image, and an eyepiece optical system.
The objective optical system is arranged in order from the object side to the image side.
The first lens group with positive refractive power and
It has a second lens group with a negative refractive power,
The second lens group is composed of one negative lens or one negative lens and one positive lens.
The second lens group is moved with respect to the optical axis of the objective optical system to perform vibration isolation.
When the focal length of the objective optical system is f0 and the focal length of the second lens group L2 is f2,
0.03 ≦ −f2 / f0 ≦ 0.24
An observation optical system characterized by satisfying the above conditions. The distance on the optical axis from the most object-side surface in the objective optical system to the most object-side surface in the erecting prism is d0, and the most object in the erecting prism from the most image-side surface in the second lens group. When the distance on the optical axis to the side surface is d02,
0.020 ≤ d02 / d0 ≤ 0.220
The observation optical system according to claim 1, wherein the observation optical system satisfies the above conditions. When the thickness of the second lens group on the optical axis is t2,
0.010 ≤ t2 / d0 ≤ 0.110
The observation optical system according to claim 1 or 2, wherein the observation optical system satisfies the above conditions. When the lateral magnification of the second lens group is β2,
1.0 ≤ β2 ≤ 5.5
The observation optical system according to any one of claims 1 to 3, wherein the observation optical system satisfies the above-mentioned condition. When the focal length of the eyepiece optical system is fe,
9.0 ≤ f0 / fe ≤ 31.0
The observation optical system according to any one of claims 1 to 4, wherein the observation optical system satisfies the above-mentioned condition. The observation optical system according to any one of claims 1 to 5, wherein the first lens group has a positive lens group, and the positive lens group moves in the optical axis direction for focusing. .. An observation device comprising the observation optical system according to any one of claims 1 to 6.

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