JP6849452B2 - Eyepiece optical system and observation device and imaging device having it - Google Patents

Description

The present invention relates to an eyepiece optical system and an observation device and an imaging device having the same, and is suitable for observing an image displayed on an image display element, for example, in an electronic viewfinder used in a video camera, a still camera, or a broadcasting camera. It is a thing.

Conventionally, an electronic viewfinder used in an optical device such as a video camera or a broadcasting camera is provided with an eyepiece optical system for magnifying and observing an image displayed on an image display surface provided inside the camera.

In recent years, with the increasing functionality of image pickup devices, there is a demand for an electronic viewfinder that has a wide field of view and can project a large image. As a method for realizing such a demand, there are a method of enlarging the image display surface such as a liquid crystal screen and a method of increasing the observation magnification of the eyepiece optical system.

Here, since enlarging the image display surface causes an increase in the size of the finder, it is preferable to increase the observation magnification of the eyepiece optical system in order to reduce the size of the finder as a whole. In order to increase the observation magnification of the eyepiece optical system, it is necessary to increase the positive refractive power in the eyepiece optical system. Here, if the eyepiece optical system is configured only with a positive lens, a large amount of axial chromatic aberration, chromatic aberration of magnification, and the like occur, and it becomes difficult to correct these. Therefore, in order to obtain a high-definition observation image while increasing the observation magnification of the eyepiece optical system, it is preferable to configure the eyepiece optical system by using a negative lens in addition to the positive lens. As a result, it is possible to obtain an observation image in which axial chromatic aberration and chromatic aberration of magnification are satisfactorily corrected.

In addition, there is a demand for a finder with a long eye relief that can be used even when the user wears glasses.

Patent Document 1 is composed of a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens having a positive refractive power in this order from the object side to the observation side. The eyepiece optical system is disclosed. By appropriately setting the refractive powers of the two positive lenses arranged on the observation side, the observation magnification is improved and the viewing angle is expanded.

JP-A-2015-75713

In the eyepiece optical system of Patent Document 1, in order to realize miniaturization, the radius of curvature of the lens surface on the observation side of the first lens is shortened, and the distance between the first lens and the second lens is narrowed. As a result, the light rays greatly refracted on the exit surface of the first lens are greatly refracted again on the incident surface of the second lens, and off-axis aberrations such as curvature of field are likely to occur.

An object of the present invention is to provide an eyepiece optical system having a long eye relief, a wide viewing angle, and high optical performance, and an observation device and an imaging device having the same.

In the eyepiece optical system of the present invention, a first lens having a positive refractive force, a second lens having a negative refractive force, a third lens having a positive refractive force, and a positive refractive force arranged in order from the object side to the observation side. The eyepiece optical system composed of the fourth lens, the focal distance of the third lens is f3, the focal distance of the eyepiece optical system is f, and the radius of curvature of the lens surface on the observation side of the first lens is R12. The radius of curvature of the lens surface on the object side of the second lens is R21, the radius of curvature of the lens surface on the observation side of the third lens is R32, and the radius of curvature of the lens surface of the fourth lens on the object side is R41 . When the radius of curvature of the lens surface on the object side of the third lens is R31 ,
1.50 ≦ f3 / f ≦ 20.00
-6.84 ≤ (R21 + R12) / (R21-R12) ≤ 0.00
-3.40 ≤ (R41 + R32) / (R41-R32) ≤ 8.00
-25.00 ≤ (R32 + R31) / (R32-R31) ≤ -1.71
It is characterized in that it satisfies the conditional expression.

According to the present invention, an eyepiece optical system having a long eye relief, a wide viewing angle, and high optical performance can be obtained.

It is a lens sectional view of the eyepiece optical system of Example 1 of this invention. It is each aberration diagram of the eyepiece optical system of Example 1 of this invention. It is a lens sectional view of the eyepiece optical system of Example 2 of this invention. It is each aberration diagram of the eyepiece optical system of Example 2 of this invention. It is a lens sectional view of the eyepiece optical system of Example 3 of this invention. It is each aberration diagram of the eyepiece optical system of Example 3 of this invention. It is a lens sectional view of the eyepiece optical system of Example 4 of this invention. It is each aberration diagram of the eyepiece optical system of Example 4 of this invention. It is a lens sectional view of the eyepiece optical system of Example 5 of this invention. It is each aberration diagram of the eyepiece optical system of Example 5 of this invention. It is a lens sectional view of the eyepiece optical system of Example 6 of this invention. It is each aberration diagram of the eyepiece optical system of Example 6 of this invention. It is a lens sectional view of the eyepiece optical system of Example 7 of this invention. It is each aberration diagram of the eyepiece optical system of Example 7 of this invention. It is a schematic diagram of the main part of the image pickup apparatus of this invention.

Hereinafter, the eyepiece optical system of the present invention, an observation device having the same, and an imaging device will be described in detail with reference to the accompanying drawings. The eyepiece optical system of the present invention is arranged in order from the object side to the observation side (eye point side), the first lens L1 having a positive refractive power, the second lens L2 having a negative refractive power, and the third lens L2 having a positive refractive power. It is composed of a lens L3 and a fourth lens L4 having a positive refractive power.

FIG. 1 is a cross-sectional view of the lens of the eyepiece optical system of Example 1 in a diopter-1 diopter (reference state). FIG. 2 is an aberration diagram in the reference state of the eyepiece optical system of Example 1. FIG. 3 is a cross-sectional view of the lens of the eyepiece optical system of the second embodiment in the diopter-1 diopter (reference state). FIG. 4 is an aberration diagram in the reference state of the eyepiece optical system of the second embodiment.

FIG. 5 is a cross-sectional view of the lens of the eyepiece optical system of Example 3 in the diopter-1 diopter (reference state). FIG. 6 is an aberration diagram in the reference state of the eyepiece optical system of Example 3. FIG. 7 is a cross-sectional view of the lens of the eyepiece optical system of the fourth embodiment in the diopter-1 diopter (reference state). FIG. 8 is an aberration diagram in the reference state of the eyepiece optical system of Example 4.

FIG. 9 is a cross-sectional view of the lens of the eyepiece optical system of Example 5 in the diopter-1 diopter (reference state). FIG. 10 is an aberration diagram in the reference state of the eyepiece optical system of Example 5. FIG. 11 is a cross-sectional view of the lens of the eyepiece optical system of Example 6 in the diopter-1 diopter (reference state). FIG. 12 is an aberration diagram in the reference state of the eyepiece optical system of Example 6.

FIG. 13 is a cross-sectional view of the lens of the eyepiece optical system of Example 7 in the diopter-1 diopter (reference state). FIG. 14 is an aberration diagram in the reference state of the eyepiece optical system of Example 7. FIG. 15 is a schematic view of a main part of an image pickup apparatus including the eyepiece optical system of the present invention.

The eyepiece optical system of each embodiment is used in an electronic viewfinder of an imaging device such as a digital camera or a video camera. In the cross-sectional view of the lens, the left side is the object (image display surface) side, and the right side is the observation side. CG is a cover glass for protecting the eyepiece optical system. The EP is an eye point for the user to observe the image displayed on the image display element. Here, the eye point EP may be moved in the optical axis direction within a range in which the off-axis light rays emitted from the image display element can pass through the observer's pupil.

The eye relief is the distance from the lens surface on the observation side of the eyepiece optical system to the eye point EP, and it can be said that the longer the eye relief is, the more convenient the eyepiece optical system is for the user.

Each aberration diagram shows the aberration that occurs in the eyepiece optical system of each embodiment when the finder diopter is -1 diopter (reference state). In each aberration diagram, spherical aberration, astigmatism, distortion, and chromatic aberration are shown in order from the left.

The spherical aberration diagram shows spherical aberration with respect to the d-line (wavelength 587.6 nm) and the F-line (wavelength 486.1 nm). In the astigmatism diagram, dΔS and dΔM indicate astigmatism in the sagittal image plane and the meridional image plane with respect to the d line, respectively. fΔS and fΔM indicate astigmatism in the sagittal image plane and the meridional image plane with respect to the F line, respectively. Distortion is shown for line d. The chromatic aberration diagram shows the chromatic aberration on the F line.

Here, if the eyepiece optical system is configured only with a positive lens, a large amount of axial chromatic aberration, chromatic aberration of magnification, and the like occur, and it becomes difficult to correct these. Therefore, in the present invention, the eyepiece optical system is configured by using a negative lens in addition to the positive lens.

In addition, if an eyepiece with a long eye relief and a wide viewing angle is realized, the lens diameter of the eyepiece will increase, and off-axis rays will pass through a position far away from the optical axis, resulting in curvature of field, etc. Off-axis aberration is likely to occur. Therefore, in the present invention, by appropriately setting the shape of each lens constituting the eyepiece optical system, an eyepiece optical system in which the eye relief is long and off-axis aberrations such as curvature of field are satisfactorily corrected is realized. ..

The eyepiece optical system of each embodiment is characterized in that the following conditional expression is satisfied.
1.50 ≦ f3 / f ≦ 20.00… (1)
-15.00 ≤ (R21 + R12) / (R21-R12) ≤ 0.00 ... (2)
-3.40 ≤ (R41 + R32) / (R41-R32) ≤ 8.00 ... (3)

Here, the focal length of the third lens L3 is f3, the focal length of the entire eyepiece optical system is f, the radius of curvature of the lens surface on the observation side of the first lens L1 is R12, and the lens surface of the second lens L2 on the object side. Let R21 be the radius of curvature of. Further, the radius of curvature of the lens surface on the observation side of the third lens L3 is R32, and the radius of curvature of the lens surface of the fourth lens L4 on the object side is R41.

The conditional expression (1) is a conditional expression that defines the ratio between the focal length f3 of the third lens L3 and the focal length f of the entire eyepiece optical system. When the focal length f3 of the third lens L3 becomes shorter than the lower limit of the conditional expression (1), the refractive power of the third lens L3 becomes too strong. As a result, it becomes difficult to secure a sufficient eye relief, which is not preferable.

When the focal length f3 of the third lens L3 becomes longer than the upper limit of the conditional expression (1), the refractive power of the third lens L3 becomes too weak. As a result, the refractive power of the entire eyepiece optical system cannot be sufficiently strengthened, and it becomes difficult to improve the observation magnification, which is not preferable.

The conditional expression (2) is a conditional expression that defines the shape of the air lens formed by the lens surface on the observation side of the first lens L1 and the lens surface on the object side of the second lens L2. If it is less than the lower limit of the conditional expression (2), the curvatures of the lens surface on the observation side of the first lens L1 and the lens surface on the object side of the second lens L2 become too close. Considering the miniaturization of the eyepiece optical system, the distance between the first lens L1 and the second lens L2 becomes shorter, and the light rays greatly refracted on the exit surface of the first lens are greatly refracted again on the incident surface of the second lens. The lens. As a result, many off-axis aberrations such as curvature of field occur, which is not preferable.

If the upper limit of the conditional expression (2) is exceeded, the radius of curvature of the lens surface on the object side of the second lens L2 becomes too long with respect to the lens surface on the observation side of the first lens L1. As a result, it becomes difficult to greatly refract the light beam on the lens surface of the second lens L2 on the object side, and it becomes difficult to sufficiently expand the viewing angle, which is not preferable.

The conditional expression (3) is a conditional expression that defines the shape of the air lens formed by the lens surface on the observation side of the third lens L3 and the lens surface on the object side of the fourth lens L4. If it is less than the lower limit of the conditional expression (3), the radius of curvature of the lens surface on the observation side of the third lens L3 becomes too short. As a result, it becomes difficult to secure a sufficient eye relief, which is not preferable. If the upper limit of the conditional expression (3) is exceeded, the radius of curvature of the lens surface of the fourth lens L4 on the object side becomes too long. As a result, it becomes difficult to sufficiently expand the viewing angle, which is not preferable.

In the eyepiece optical system of each embodiment, by setting the shape of each lens so as to satisfy the conditional expressions (1) to (3), the eyepiece has a long eye relief, a wide viewing angle, and high optical performance. An optical system can be obtained.

In each embodiment, the numerical range of the conditional expressions (1) to (3) is preferably set as follows.
1.55 ≦ f3 / f ≦ 15.00 ... (1a)
-12.000 ≤ (R21 + R12) / (R21-R12) ≤ -1.50 ... (2a)
-2.00 ≤ (R41 + R32) / (R41-R32) ≤ 5.00 ... (3a)

Further, it is more preferable to set the numerical range of the conditional expressions (1) to (3) as follows.
1.60 ≦ f3 / f ≦ 10.00 ... (1b)
-10.00 ≤ (R21 + R12) / (R21-R12) ≤ -2.50 ... (2b)
-1.00 ≤ (R41 + R32) / (R41-R32) ≤ 4.00 ... (3b)

Further, in each embodiment, it is more preferable to satisfy one or more of the following conditional expressions.
0.00 <d23 / d12 ≦ 0.75 ... (4)
-25.00 ≤ (R32 + R31) / (R32-R31) ≤ 0.50 ... (5)
0.70 ≦ f3 / f4 ≦ 30.00… (6)
1.45 ≤ Nda ≤ 1.85 ... (7)

Here, the distance between the first lens L1 and the second lens L2 on the optical axis is d12, the distance between the second lens L2 and the third lens L3 on the optical axis is d23, and the distance between the third lens L3 and the lens surface on the object side is d23. The radius of curvature is R31, and the focal length of the fourth lens L4 is f4. Further, the average value of the refractive indexes of the materials of each lens constituting the eyepiece optical system is defined as Nda.

If the distance d12 on the optical axis between the first lens L1 and the second lens L2 becomes shorter than the upper limit of the conditional expression (4), many off-axis aberrations such as curvature of field occur, which is not preferable. Further, when the distance d23 on the optical axis between the second lens L2 and the third lens L3 becomes longer than the upper limit value of the conditional equation (4), the second lens L2 having a negative refractive power and the positive refractive power th It is not preferable because it becomes difficult to sufficiently obtain the effect of correcting chromatic aberration by the three-lens L3.

The conditional expression (5) is a conditional expression that defines the shape of the third lens L3. The lens surface of the third lens L3 on the object side has a relatively long radius of curvature to correct chromatic aberration. The radius of curvature of the lens surface on the observation side of the third lens L3 is relatively short, and the angle of light rays incident on the fourth lens L4 is loosened to reduce curvature of field.

If it falls below the lower limit of the conditional expression (5), the curvature of the lens surface on the object side of the third lens L3 and the curvature of the lens surface on the observation side become too close to each other, and both correction of chromatic aberration and reduction of curvature of field are achieved. This is not preferable because it makes it difficult. If the upper limit of the conditional expression (5) is exceeded, the radius of curvature of the lens surface on the observation side of the third lens L3 becomes too short. As a result, it becomes difficult to secure a sufficient eye relief, which is not preferable.

The conditional expression (6) is a conditional expression that defines the ratio between the focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4. When the focal length f3 of the third lens L3 becomes shorter than the lower limit of the conditional expression (6), the refractive power of the third lens L3 becomes too strong. As a result, it becomes difficult to secure a sufficient eye relief, which is not preferable. When the focal length f4 of the fourth lens L4 becomes longer than the upper limit of the conditional expression (6), the refractive power of the fourth lens L4 becomes too weak. As a result, it becomes difficult to sufficiently expand the viewing angle, which is not preferable.

The conditional expression (7) is a conditional expression that defines the average value Nda of the refractive indexes of the materials of each lens constituting the eyepiece optical system. If it is less than the lower limit of the conditional expression (7), it becomes difficult to sufficiently expand the viewing angle, which is not preferable. If the upper limit of the conditional expression (7) is exceeded, the observed image tends to be yellowish, which is not preferable.

In each embodiment, the numerical range of the conditional expressions (4) to (7) is preferably set as follows.
0.00 <d23 / d12 ≦ 0.60 ... (4a)
-23.00 ≤ (R32 + R31) / (R32-R31) ≤ 0.10 ... (5a)
0.80 ≦ f3 / f4 ≦ 25.00 ... (6a)
1.50 ≤ Nda ≤ 1.80 ... (7a)

Further, it is more preferable to set the numerical range of the conditional expressions (4) to (7) as follows.
0.00 <d23 / d12 ≦ 0.50 ... (4b)
-18.00 ≤ (R32 + R31) / (R32-R31) ≤ 0.00 ... (5b)
0.90 ≦ f3 / f4 ≦ 20.00 ... (6b)
1.55 ≤ Nda ≤ 1.75 ... (7b)

When the eyepiece optical system of each embodiment is used for the observation device for observing the image displayed on the image display surface, it is preferable that one or more of the following conditional expressions are satisfied.
0.25 ≤ H / f ≤ 0.55 ... (8)
0.00 <d1 / f ≦ 0.80 ... (9)

Here, half of the diagonal length of the image display surface is H, and the distance from the image display surface to the first lens L1 in the diopter −1.0 diopter (reference state) is d1.

If the image display surface becomes too large beyond the upper limit of the conditional expression (8), the height of the light beam incident on the first lens L1 becomes high and the effective diameter of the first lens L1 increases, which is not preferable. If the image display surface becomes too small below the lower limit of the conditional expression (8), it becomes necessary to increase the magnification of the eyepiece optical system in order to project a large image. It is not preferable to increase the refractive power of the entire eyepiece optical system in order to increase the magnification of the eyepiece optical system because it becomes difficult to satisfactorily correct various aberrations.

When the distance d1 from the image display surface to the first lens L1 becomes longer than the upper limit of the conditional expression (9), the height of the light beam incident on the first lens L1 becomes higher and the effective diameter of the first lens L1 becomes higher. Is not preferable because it increases. Further, it is necessary to greatly bounce the light rays greatly refracted by the first lens L1 by the second lens L2, which causes a lot of curvature of field, which is not preferable.

In each embodiment, the numerical range of the conditional expressions (8) and (9) is preferably set as follows.
0.30 ≤ H / f ≤ 0.50 ... (8a)
0.00 <d1 / f ≦ 0.60 ... (9a)

Further, it is more preferable to set the numerical range of the conditional expressions (8) and (9) as follows.
0.35 ≤ H / f ≤ 0.45 ... (8b)
0.00 <d1 / f ≦ 0.55 ... (9b)

Next, numerical examples 1 to 7 corresponding to Examples 1 to 7 of the present invention are shown. In each numerical embodiment, i indicates the order of the optical surfaces from the image display surface side. ri is the radius of curvature of the i-th optical plane (i-plane), di is the distance between the i-th plane and the i + 1 plane, and ndi and νdi are the refraction of the material of the i-th optical member with respect to the d line, respectively. Shows the rate and Abbe number. r1 indicates an image display surface. The surface on the most observing side shows the eye point EP in the reference state of the eyepiece optical system of each embodiment.

Further, when K is the eccentricity, A4, A6, and A8 are the aspherical coefficients, and the displacement in the optical axis direction at the position of the height h from the optical axis is x with respect to the surface apex, the aspherical shape is
x = (h ² / R) / [1 + [1- (1 + K) (h / R) ² ] ^1/2 ] + A4h ⁴ + A6h ⁶ + A8h ⁸
Is displayed. However, R is the radius of curvature of the paraxial axis. The surface marked with * on the right side of the surface number indicates that it is an aspherical surface. In addition, the display of the "E-Z" means ^{"10 -Z".}

The focal length of the eyepiece optical system of Example 1 is 18.41 mm, and the viewfinder including the eyepiece optical system of Example 1 has a diagonal length of 2H = 12.5 mm and a viewing angle of 2ω = 37.1 degrees on the image display surface. .. The focal length of the eyepiece optical system of Example 2 is 17.85 mm, and the viewfinder including the eyepiece optical system of Example 1 has a diagonal length of 2H = 12.5 mm and a viewing angle of 2ω = 37.8 degrees on the image display surface. .. The focal length of the eyepiece optical system of Example 3 is 13.32 mm, and the viewfinder including the eyepiece optical system of Example 3 has a diagonal length of 2H = 10.0 mm and a viewing angle of 2ω = 40.0 degrees on the image display surface. .. The focal length of the eyepiece optical system of Example 4 is 13.20 mm, and the viewfinder including the eyepiece optical system of Example 4 has a diagonal length of 2H = 10.0 mm and a viewing angle of 2ω = 40.7 degrees on the image display surface. ..

The focal length of the eyepiece optical system of Example 5 is 22.00 mm, and the viewfinder including the eyepiece optical system of Example 5 has a diagonal length of 2H = 16.8 mm and a viewing angle of 2ω = 40.9 degrees on the image display surface. .. The focal length of the eyepiece optical system of Example 6 is 19.86 mm, and the viewfinder including the eyepiece optical system of Example 6 has a diagonal length of 2H = 12.5 mm and a viewing angle of 2ω = 34.3 degrees on the image display surface. .. The focal length of the eyepiece optical system of Example 7 is 15.43 mm, and the viewfinder including the eyepiece optical system of Example 7 has a diagonal length of 2H = 10.0 mm and a viewing angle of 2ω = 34.9 degrees on the image display surface. ..

[Numerical Example 1]
Unit mm
Surface data

Aspherical data

[Numerical Example 2]
Unit mm
Surface data

Aspherical data

[Numerical Example 3]
Unit mm
Surface data

Aspherical data

[Numerical Example 4]
Unit mm
Surface data

Aspherical data

[Numerical Example 5]
Unit mm
Surface data

Aspherical data

[Numerical Example 6]
Unit mm
Surface data

Aspherical data

[Numerical Example 7]
Unit mm
Surface data

Aspherical data

Subsequently, Table 1 shows the numerical values of the above-mentioned conditional expressions in each numerical example.

Next, an embodiment of the image pickup apparatus using the eyepiece optical system shown in each example will be described with reference to FIG. The object image formed by the image pickup optical system 101 is converted into an electric signal by the image pickup element 102 which is a photoelectric conversion element. As the image sensor 102, a CCD sensor, a CMOS sensor, or the like is used.

The output signal from the image sensor 102 is processed by the image processing circuit 103 to generate image data. The image data is recorded on a recording medium such as a semiconductor memory, a magnetic tape, or an optical disk. The finder unit 105 includes an image display element 1051 and an eyepiece optical system 1052 of each embodiment. The image display element 1051 is composed of a liquid crystal display element or the like, and displays an image based on the image data generated by the image processing circuit 103.

By applying the eyepiece optical system of the present invention to an image pickup device such as a digital camera or a video camera in this way, it is possible to obtain an image pickup device having a long eye relief, a wide viewing angle, and high optical performance.

L1 1st lens L2 2nd lens L3 3rd lens L4 4th lens CG cover glass EP eye point

Claims (8)

It is composed of a first lens with a positive refractive power, a second lens with a negative refractive power, a third lens with a positive refractive power, and a fourth lens with a positive refractive power, which are arranged in order from the object side to the observation side. It is an eyepiece optical system
The focal distance of the third lens is f3, the focal distance of the eyepiece optical system is f, the radius of curvature of the lens surface on the observation side of the first lens is R12, and the radius of curvature of the lens surface of the second lens on the object side. R21, the radius of curvature of the lens surface on the observation side of the third lens is R32, the radius of curvature of the lens surface of the fourth lens on the object side is R41 , and the radius of curvature of the lens surface of the third lens on the object side is R31 . When you do
1.50 ≦ f3 / f ≦ 20.00
-6.84 ≤ (R21 + R12) / (R21-R12) ≤ 0.00
-3.40 ≤ (R41 + R32) / (R41-R32) ≤ 8.00
-25.00 ≤ (R32 + R31) / (R32-R31) ≤ -1.71
An eyepiece optical system characterized by satisfying the conditional expression. When the distance between the first lens and the second lens on the optical axis is d12 and the distance between the second lens and the third lens on the optical axis is d23,
0.00 <d23 / d12 ≦ 0.75
The eyepiece optical system according to claim 1, wherein the conditional expression is satisfied. When the focal length of the fourth lens is f4,
0.70 ≤ f3 / f4 ≤ 30.00
The eyepiece optical system according to claim 1 or 2 , wherein the conditional expression is satisfied. When the average value of the refractive indexes of the materials of each lens constituting the eyepiece optical system is Nda,
1.45 ≤ Nda ≤ 1.85
The eyepiece optical system according to any one of claims 1 to 3, wherein the conditional expression is satisfied. An image display device for displaying an image, and having an ocular optical system according to any one of claims 1 to 4 for observing the image displayed on the image display surface of the image display device Observation device. When half of the diagonal length of the image display surface is H,
0.25 <H / f <0.55
The observation device according to claim 5 , wherein the observation device satisfies the conditional expression. When the distance from the image display surface to the first lens in the diopter -1.0 diopter is d1
0.00 <d1 / f ≦ 0.80
The observation device according to claim 5 or 6 , wherein the conditional expression is satisfied. With the image sensor
An imaging optical system that forms an object image on the image sensor,
An image display element that displays the object image and
An image pickup apparatus comprising the eyepiece optical system according to any one of claims 1 to 4 , which is used for observing an image displayed by the image display element.

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