JP7451269B2 - Eyepiece optical system and imaging device having the same - Google Patents

Description

The present invention relates to an eyepiece optical system, and particularly to an eyepiece optical system suitable for an electronic viewfinder.

BACKGROUND OF THE INVENTION Hitherto, an eyepiece optical system for observing a small display panel with a diagonal length of about 10 mm has been proposed. This eyepiece optical system consists of a first lens with positive refractive power, a second lens with negative refractive power, and a second lens with positive refractive power in order from the display panel side (object side) to the exit side (observer side). An eyepiece optical system having three lenses is known.

For example, in Patent Document 1, from the display panel side, the first lens has a positive refractive power, the second lens has a negative refractive power and has a meniscus shape with its concave surface facing the display panel side, and the second lens has a positive refractive power. An eyepiece optical system having three lenses is disclosed. Further, in Patent Document 1, the focal length of the second lens, the distance between the first lens and the second lens on the optical axis, and the distance between the second lens and the third lens on the optical axis are appropriately set. In addition, by appropriately setting the paraxial radius of curvature of the exit side surface of the first lens and the paraxial radius of curvature of the display panel side surface of the second lens, the viewing angle is wide and the sensitivity of each lens is increased. We are proposing a high-performance eyepiece optical system that can reduce this.

Furthermore, Patent Document 2 discloses an eyepiece optical system having three lenses, in order from the display panel side: a first lens with a positive refractive power, a second lens with a negative refractive power, and a third lens with a positive refractive power. Disclosed. Furthermore, in Patent Document 2, by appropriately setting the focal length of the first lens, the focal length of the second lens, and the focal length of the entire system, the viewing angle can be widened and various aberrations such as field curvature and distortion can be avoided. We are proposing an eyepiece optical system that suppresses this occurrence.

On the other hand, in order to expand the functionality of the electronic viewfinder, there is an idea to add functions other than viewing the display panel. For example, a line-of-sight detection function is known that detects the line of sight of an observer observing a display panel and detects which position on the panel the viewer is viewing. An idea is known that allows quick camera operations by selecting the main subject and performing various operations based on this line-of-sight direction information. In order to detect the line of sight, it is necessary to provide an optical path branching means on the finder optical path. In other words, by branching and extracting a part of the light beam by the optical path branching means, it becomes possible to detect the line of sight of the observer. A dichroic mirror using a prism is known as an optical path branching means.

JP2014-202770A Japanese Patent Application Publication No. 2014-228583

However, in the conventional techniques disclosed in Patent Document 1 and Patent Document 2 mentioned above, there is not enough space in the eyepiece optical system to arrange the optical path branching means. For this reason, it is not possible to incorporate a line of sight detection function into the eyepiece optical system.

Therefore, an object of the present invention is to provide an eyepiece optical system that can secure a sufficient space within the eyepiece optical system, satisfy a wide viewing angle, and sufficiently correct various aberrations such as field curvature and astigmatism. It is to be.

An eyepiece optical system as one aspect of the present invention includes a first lens with a positive refractive power, a second lens with a negative refractive power, and a second lens with a positive refractive power, which are arranged in order from the display element side to the viewer side. an eyepiece optical system having a third lens, wherein the maximum image height of the display element is H, the focal length of the eyepiece optical system at standard diopter is f, the focal length of the second lens is f2; When the distance on the optical axis from the display element to the lens surface of the first lens on the display element side is skd, a predetermined condition is satisfied.

Other objects and features of the invention are explained in the following embodiments.

According to the present invention, it is an object to provide an eyepiece optical system that can secure a sufficient space in the eyepiece optical system, satisfy a wide viewing angle, and sufficiently correct various aberrations such as field curvature and astigmatism. I can do it.

1 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 1 of the present invention. 3 shows each aberration of the eyepiece optical system according to Example 1 of the present invention. FIG. 3 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 2 of the present invention. It shows each aberration of the eyepiece optical system according to Example 2 of the present invention. FIG. 3 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 3 of the present invention. It shows each aberration of the eyepiece optical system according to Example 3 of the present invention. FIG. 4 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 4 of the present invention. It shows each aberration of the eyepiece optical system according to Example 4 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 5 of the present invention. It shows each aberration of the eyepiece optical system according to Example 5 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 6 of the present invention. It shows each aberration of the eyepiece optical system according to Example 6 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 7 of the present invention. It shows each aberration of the eyepiece optical system according to Example 7 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 8 of the present invention. It shows each aberration of the eyepiece optical system according to Example 8 of the present invention. FIG. 9 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 9 of the present invention. It shows each aberration of the eyepiece optical system according to Example 9 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 10 of the present invention. It shows each aberration of the eyepiece optical system according to Example 10 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 11 of the present invention. It shows each aberration of the eyepiece optical system according to Example 11 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 12 of the present invention. It shows each aberration of the eyepiece optical system according to Example 12 of the present invention. FIG. 7 is a cross-sectional view showing a lens configuration of an eyepiece optical system according to Example 13 of the present invention. It shows each aberration of the eyepiece optical system according to Example 13 of the present invention. 1 is a schematic diagram of main parts of an imaging device of the present invention.

In order to magnify and observe a small display panel LCD with a diagonal length of approximately 10 mm at a viewing angle of 35 to 45 degrees, the eyepiece optical system must have strong positive refractive power. In the peripheral area of the subject, as the height from the center increases, large curvature of field and astigmatism occur, and optical performance deteriorates.

In order to improve such field curvature and astigmatism, in the eyepiece optical system according to this embodiment, as shown in FIG. The lens is configured to have, in order from the viewer's side), a first lens L1 with a positive refractive power, a second lens L2 with a negative refractive power, and a third lens L3 with a positive refractive power.

In addition, the optical path branching means DP is arranged while maintaining the magnification of the observation device, and the distance between the display panel (display element) LCD and the eye point EP is set at a predetermined distance in order to maintain the magnification and optical performance for magnified observation. The range is as follows.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

1 and 2 are cross-sectional views showing a lens configuration of an eyepiece optical system according to Example 1 of the present invention, and diagrams showing each aberration (spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification). 3 and 4 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 2 of the present invention, and diagrams showing each aberration. 5 and 6 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 3 of the present invention, and diagrams showing each aberration. 7 and 8 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 4 of the present invention, and diagrams showing each aberration. 9 and 10 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 5 of the present invention, and diagrams showing each aberration. 11 and 12 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 6 of the present invention, and diagrams showing each aberration. 13 and 14 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 7 of the present invention, and diagrams showing each aberration. 15 and 16 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 8 of the present invention, and diagrams showing each aberration. 17 and 18 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 9 of the present invention, and diagrams showing each aberration. 19 and 20 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 10 of the present invention, and diagrams showing each aberration. 21 and 22 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 11 of the present invention, and diagrams showing each aberration. 23 and 24 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 12 of the present invention, and diagrams showing each aberration. 25 and 26 are cross-sectional views showing the lens configuration of the eyepiece optical system according to Example 13 of the present invention, and diagrams showing each aberration.

Each aberration diagram shows an aberration diagram when the finder diopter is −1 diopter (m ⁻¹ ) (standard diopter). In each aberration diagram, d and F indicate the d-line and F-line, respectively, and ΔM and ΔS indicate the meridional image plane and the sagittal image plane, respectively. In each cross-sectional view showing the lens configuration, the left side is the display panel side, and the right side is the viewer side.

As for the specific lens configuration, in Examples 1 to 7, the eyepiece optical system includes, in order from the display panel side, a first lens L1 with a positive refractive power, a second lens L2 with a negative refractive power, and a second lens L2 with a positive refractive power. It has a third lens L3 with refractive power. In Examples 8 to 13, the eyepiece optical system includes, in order from the display panel side, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, and a third lens L3 with positive refractive power. , and a fourth lens L4 with positive refractive power. In each embodiment, an optical path branching means DP assuming a dichroic prism is arranged between the display panel LCD and the first lens L1. In the eyepiece optical system of each embodiment, the diopter is adjusted by moving the lens back and forth.

The eyepiece optical system satisfies the following conditional expression, where H is the maximum image height of the display panel LCD, and f is the focal length of the eyepiece optical system at standard diopter.

0.300 < H/f <0.400...(1)
The technical meaning of conditional expression (1) will be explained. Conditional expression (1) is an expression that defines the relationship between the maximum image height of the display panel LCD and the focal length of the eyepiece optical system. This is a formula for correcting aberrations. If the upper limit of conditional expression (1) is exceeded, the focal length of the eyepiece optical system becomes short, making it impossible to satisfactorily correct various aberrations such as spherical aberration, curvature of field, and astigmatism. When the lower limit of conditional expression (1) is exceeded, the power of the eyepiece optical system becomes weaker, and the observation magnification of the eyepiece optical system decreases.

Preferably, the numerical range of conditional expression (1) is as follows.

0.305 < H/f < 0.395...(1a)
More preferably, the numerical range of conditional expression (1) is as follows.

0.307 < H/f < 0.393...(1b)
Further, when the maximum image height of the display panel LCD is H, and the distance on the optical axis from the display panel LCD to the lens surface of the first lens L1 on the display panel side is skd, the eyepiece optical system satisfies the following conditional expression. be satisfied.

0.300 < H/skd < 0.600...(2)
The technical meaning of conditional expression (2) will be explained. Conditional expression (2) is an expression that defines the relationship between the maximum image height of the display panel LCD and the distance on the optical axis from the display panel LCD to the lens surface of the first lens L1 on the display panel side. This is a formula for obtaining a wide viewing angle while ensuring the following. If the upper limit of conditional expression (2) is exceeded, the distance between the display panel LCD and the first lens L1 becomes too narrow. In this case, it becomes difficult to arrange the optical path branching means DP. When the lower limit of conditional expression (2) is exceeded, the power for observing the display panel LCD at an appropriate diopter becomes weak, making it difficult to secure a high observation magnification.

Preferably, the numerical range of conditional expression (2) is as follows.

0.305 < H/skd < 0.597...(2a)
More preferably, the numerical range of conditional expression (2) is as follows.

0.310 < H/skd < 0.595...(2b)
The eyepiece optical system satisfies the following conditional expression, where f is the focal length of the eyepiece optical system at standard diopter, and f1 is the focal length of the first lens L1.

0.55 < f1/f < 1.00...(3)
The technical meaning of conditional expression (3) will be explained. Conditional expression (3) is an expression that defines the relationship between the focal length of the first lens L1 and the focal length of the eyepiece optical system. The formula is to satisfy telecentricity on the entrance side (display panel side) of the eyepiece optical system while ensuring high magnification and a sufficient distance from the display panel LCD to the lens surface of the first lens L1 on the display panel side. be. If the upper limit of conditional expression (3) is exceeded, the power of the first lens L1 will be weakened, which will be disadvantageous for achieving high magnification, and the principal point position of the eyepiece optical system will move toward the exit side, so that It becomes difficult to ensure the distance to the lens surface of the first lens L1 on the display panel side. When the lower limit of conditional expression (3) is exceeded, the light beam emitted from the display panel LCD is largely bent by the first lens L1. In order to allow the light beam to pass through to the exit side, it is necessary to increase the exit angle from the display panel LCD, which weakens telecentricity. Since color unevenness and a decrease in light intensity occur in the display panel LCD depending on the emission angle of the light beam, it is preferable that the eyepiece optical system has telecentricity and the emission angle from the display panel LCD is small.

Note that it is preferable that the numerical range of conditional expression (3) is as follows.

0.60 < f1/f < 0.95...(3a)
More preferably, the numerical range of conditional expression (3) is as follows.

0.62 < f1/f < 0.93...(3b)
When the lenses included in the eyepiece optical system are only the first lens L1, second lens L2, and third lens L3, the focal length of the first lens L1 is f1, and the focal length of the third lens L3 is f3. When , the eyepiece optical system satisfies the following conditional expression.

0.70 < f3/f1 < 1.60...(4)
The technical meaning of conditional expression (4) will be explained. Conditional expression (4) is an expression that defines the relationship between the focal length of the third lens L3 and the focal length of the first lens L1. This is a formula for satisfying the distance on the optical axis and the aberration performance. If the upper limit of conditional expression (4) is exceeded, the power balance between the first lens L1 and the third lens L3 will be poor, and field curvature and astigmatism will worsen. When the lower limit of conditional expression (4) is exceeded, the power of the third lens L3 becomes too strong compared to the power of the first lens L1. For this reason, the principal point position of the eyepiece optical system moves too far to the exit side, making it difficult to secure the distance on the optical axis from the display panel LCD to the lens surface of the first lens L1 on the display panel side.

Note that it is preferable that the numerical range of conditional expression (4) is as follows.

0.80 < f3/f1 < 1.50...(4a)
More preferably, the numerical range of conditional expression (4) is as follows.

0.90 < f3/f1 < 1.40...(4b)
When the lenses included in the eyepiece optical system include the fourth lens L4 disposed on the observer side of the third lens L3, the eyepiece optical system satisfies the following conditional expression. Here, the focal length of the first lens L1 is f1, the focal length of the third lens L3 is f3, the focal length of the fourth lens L4 is f4, the combined focal length of the third lens L3 and the fourth lens L4 is f34, and the focal length of the fourth lens L4 is f34. Let d be the distance between the third lens L3 and the fourth lens L4 on the optical axis.

0.70 < f34/f1 <1.60...(4')
f34 = (f3×f4)/(f3+f4-d)
The technical meaning of conditional expression (4') will be explained. Conditional expression (4') is an expression that defines the relationship between the combined focal length of the third lens L3 and the fourth lens L4 and the focal length of the first lens L1, and the display of the first lens L1 from the display panel LCD. This is a formula for satisfying the distance on the optical axis to the lens surface on the panel side and aberration performance. If the upper limit of conditional expression (4') is exceeded, the power balance between the first lens L1 and the third and fourth lenses L3 and L4 will be poor, resulting in worsening of field curvature and astigmatism. When the lower limit of conditional expression (4') is exceeded, the powers of the third and fourth lenses L3 and L4 become too strong compared to the power of the first lens L1. For this reason, the principal point position of the eyepiece optical system moves too far to the exit side, making it difficult to secure the distance on the optical axis from the display panel LCD to the lens surface of the first lens L1 on the display panel side.

Preferably, the numerical range of conditional expression (4') is as follows.

0.75 < f34/f1 <1.55...(4a')
More preferably, the numerical range of (4') is as follows.

0.78 < f34/f1 <1.50...(4b')
When the focal length of the second lens L2 is f2 and the focal length of the eyepiece optical system at standard diopter is f, the eyepiece optical system satisfies the following conditional expression.

-0.90 < f2/f < -0.45...(5)
The technical meaning of conditional expression (5) will be explained. Conditional expression (5) is an expression that defines the relationship between the focal length of the second lens L2 and the focal length of the eyepiece optical system, and is an expression for achieving high magnification and satisfying aberration performance of the eyepiece optical system. If the upper limit of conditional expression (5) is exceeded, the power of the second lens L2 becomes strong and the power of the eyepiece optical system becomes weak, which is disadvantageous for increasing the magnification. When the lower limit of conditional expression (5) is exceeded, the power of the second lens L2 becomes weaker, so that the effect of correcting field curvature and astigmatism becomes weaker, and image performance deteriorates.

Note that it is preferable to set the numerical range of conditional expression (5) as follows.

-0.87 < f2/f < -0.47...(5a)
More preferably, the numerical range of conditional expression (5) is as follows.

-0.86 < f2/f < -0.49...(5b)
When the refractive index of the first lens L1 is Nd1, the eyepiece optical system satisfies the following conditional expression.

1.50<Nd1...(6)
The technical meaning of conditional expression (6) will be explained. Conditional expression (6) is an expression that defines the refractive index of the first lens L1, and is an expression that satisfies the aberration performance of the eyepiece optical system. If conditional expression (6) is not satisfied, the curvature shape of the first lens L1 becomes severe, and spherical aberration and field curvature worsen.

Note that it is preferable to set the numerical range of conditional expression (6) as follows.

1.60 < Nd1...(6a)
More preferably, the numerical range of conditional expression (6) is as follows.

1.70 < Nd1...(6b)
When the refractive index of the second lens L2 is Nd2, the eyepiece optical system satisfies the following conditional expression.

1.60<Nd2…(7)
The technical meaning of conditional expression (7) will be explained. Conditional expression (7) is an expression that defines the refractive index of the second lens L2, and is an expression that satisfies the aberration performance of the eyepiece optical system. If conditional expression (7) is not satisfied, the curvature shape of the second lens L2 becomes severe, and the effect of correcting field curvature and astigmatism deteriorates.

Note that it is preferable that the numerical range of conditional expression (7) is as follows.

1.62 < Nd2...(7a)
More preferably, the numerical range of conditional expression (7) is as follows.

1.63 < Nd2...(7b)
When the refractive index of the third lens L3 is Nd3, the eyepiece optical system satisfies the following conditional expression.

1.50<Nd3...(8)
The technical meaning of conditional expression (8) will be explained. Conditional expression (8) is an expression that defines the refractive index of the third lens L3, and is an expression for satisfying the aberration performance of the eyepiece optical system. If conditional expression (8) is not satisfied, the curvature shape of the third lens L3 becomes severe, which has a negative effect on spherical aberration and curvature of field.

Preferably, the numerical range of conditional expression (8) is as follows.

1.51 < Nd3...(8a)
More preferably, the numerical range of conditional expression (8) is as follows.

1.52 < Nd3...(8b)
When the radius of curvature of the second lens L2 on the display panel side is L2R1, the radius of curvature on the exit side is L2R2, and the shape factor of the second lens L2 is SFL2, the eyepiece optical system satisfies the following conditional expression.

-4.00 < SFL2 < -0.90...(9)
SFL2 = (L2R1+L2R2)/(L2R1-L2R2)
The technical meaning of conditional expression (9) will be explained. Conditional expression (9) is an expression that defines the relationship between the curvatures of the second lens L2, and is an expression for achieving high magnification and satisfying the aberration balance of the eyepiece optical system. If the upper limit of conditional expression (9) is exceeded, the curvature of the exit-side surface becomes weaker, and the positive power that the exit-side surface contributes to the eyepiece optical system becomes weaker, which is disadvantageous for increasing the magnification. If the lower limit of conditional expression (9) is exceeded, the effect of correcting field curvature and astigmatism by the surface on the display panel side will be offset by the surface on the exit side, and the aberration correction effect will not be sufficient.

Note that it is preferable to set the numerical range of conditional expression (9) as follows.

-3.50 < SFL2 < -0.95...(9a)
More preferably, the numerical range of conditional expression (9) is as follows.

-3.30 < SFL2 < -0.98...(9b)
When the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, and the focal length of the eyepiece optical system at standard diopter is f, the eyepiece optical system is as follows: satisfies the conditional expression.

0.60<(f1/f + |f2|/f+f3/f)/3<0.95
…(10)
The technical meaning of conditional expression (10) will be explained. Conditional expression (10) is an expression that defines the relationship between the focal lengths of the first, second, and third lenses L1, L2, and L3 in the focal length of the eyepiece optical system, and in order to satisfy high magnification and aberration performance. The formula is If the upper limit of conditional expression (10) is exceeded, the power of each lens is weak, making it difficult to obtain sufficient positive refractive power or a correction effect using a negative lens, which is disadvantageous for increasing magnification. When the lower limit of conditional expression (10) is exceeded, the power of each lens becomes too strong, which worsens various aberrations such as spherical aberration, curvature of field, and distortion.

Preferably, the numerical range of conditional expression (10) is as follows.

0.65<(f1/f + |f2|/f+f3/f)/3<0.93
...(10a)
More preferably, the numerical range of conditional expression (10) is as follows.

0.67<(f1/f + |f2|/f+f3/f)/3<0.91
...(10b)
When the focal length of the eyepiece optical system at standard diopter is f, and the radius of curvature of the first lens L1 on the display panel side is L1R1, the eyepiece optical system satisfies the following conditional expression.

1.0 < L1R1/f < 4.5...(11)
The technical meaning of conditional expression (11) will be explained. Conditional expression (11) is an expression that defines the relationship between the focal length of the eyepiece optical system and the curvature of the surface of the first lens L1 on the display panel side, and in order to satisfy high magnification and telecentricity of the eyepiece optical system. The formula is When the upper limit of conditional expression (11) is exceeded, the positive power of the display panel side surface of the first lens L1 with respect to the focal length of the eyepiece optical system becomes weak, which is disadvantageous for increasing the magnification. When the lower limit of conditional expression (10) is exceeded, the power of the lens surface of the first lens L1 on the display panel side to bend the light rays becomes stronger, and the panel exit angle increases, resulting in uneven panel color and a decrease in light intensity. Put it away.

Preferably, the numerical range of conditional expression (11) is as follows.

1.1 < L1R1/f < 4.3...(11a)
More preferably, the numerical range of conditional expression (11) is as follows.

1.2 < L1R1/f < 4.2...(11b)
When the focal length of the eyepiece optical system at standard diopter is f and the radius of curvature on the exit side of the third lens L3 is L3R2, the eyepiece optical system satisfies the following conditional expression.

-1.10 < L3R2/f < -0.50...(12)
The technical meaning of conditional expression (12) will be explained. Conditional expression (12) is an expression that defines the relationship between the focal length of the eyepiece optical system and the curvature of the exit side of the third lens L3, and is an expression for satisfying aberration performance and high magnification of the eyepiece optical system. . If the upper limit of conditional expression (13) is exceeded, the curvature of the exit side surface of the third lens L3 becomes too strong, which worsens the curvature of field and astigmatism that occur. When the lower limit of conditional expression (12) is exceeded, the curvature of the exit side surface of the third lens L3 becomes weaker, and the contribution of positive power to higher magnification becomes weaker.

Note that it is preferable to set the numerical range of conditional expression (12) as follows.

-1.06 < L3R2/f < -0.52...(12a)
More preferably, the numerical range of conditional expression (12) is as follows.

-1.05 < L3R2/f < -0.53...(12b)
Examples 1 to 7 are composed of a positive first lens L1, a negative second lens L2, and a positive third lens L3 in order from the display panel side, thereby eliminating spherical aberration, curvature of field, and astigmatism. , various aberrations such as chromatic aberration can be corrected well. In order to further widen the viewing angle, as in Examples 8 to 13, from the display panel side, the positive first lens L1, the negative second lens L2, the positive third lens L3, and the positive fourth lens L4 are used. may be configured. With this configuration, various aberrations such as spherical aberration, field curvature, astigmatism, and chromatic aberration can be favorably corrected while providing a wider viewing angle.

By satisfying the above conditions, the eyepiece optical system according to the present invention has a wide viewing angle and is free from spherical aberration, field curvature, and It is possible to provide an eyepiece optical system in which various aberrations including point aberration and chromatic aberration are sufficiently corrected.

Numerical Examples 1 to 13 corresponding to Examples 1 to 13 of the present invention are shown below.

In each numerical example, the screen display diagonal length means the diagonal length of the display element, and is twice the maximum image height of the object plane (display panel). Further, "ri" indicates the paraxial radius of curvature of the i-th lens curved surface in order from the display panel side, and "di" indicates the on-axis distance between the i-th surface and the i+1-th surface from the display panel side. . Furthermore, "Nd" indicates the refractive index of the glass material for the d-line (wavelength = 578.6 nm), and "vd" indicates the Abbe number of the glass material for the d-line. The Abbe number νd of a certain material is νd when the refractive index at the Fraunhofer line d line (587.6 nm), F line (486.1 nm), and C line (656.3 nm) is Nd, NF, and NC. It is expressed as =(Nd-1)/(NF-NC). Note that the unit of length described is [mm] unless otherwise specified. However, since the optical system can obtain the same optical performance even if it is proportionally enlarged or reduced, the unit is not limited to [mm], and other suitable units can be used.

Furthermore, if the optical surface is an aspherical surface, an * symbol is attached to the right side of the surface number. In each numerical example, the aspherical surface is an aspherical shape defined by the following formula.

x=(h ² /R)/[1+{1-(1+k)(h/R) ² } ^1/2 ]+A ₂ ×h ² +A ₄ ×h ⁴ +A ₆ ×h ⁶ +A ₈ ×h ⁸ +A ₁₀ ×h ¹⁰
In the above equation, x is the distance in the optical axis direction from the apex of the lens surface, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial radius of curvature at the apex of the lens surface, and k is a conic constant, and A ₂ , A ₄ , A ₆ , A ₈ , and A ₁₀ are aspheric coefficients of each order. In the table showing aspherical surface data, "ei" represents an exponential expression with the base of 10, that is, "10 ^-i ".

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

[Numerical Example 1]
At standard diopter focal length f=18.7 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 7.50 1.83400 37.2
4 ∞ (variable)
5 45.231 4.65 1.76802 49.2
6* -15.489 3.49
7* -4.014 1.20 1.63550 23.9
8* -7.629 0.55
9 151.752 6.87 1.76802 49.2
10* -14.490 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-6.66748e-001 A4=-2.85417e-005 A6=1.39887e-006 A8=-1.10652e-008 A10=2.81105e-011
Side 7
K=-2.18343e+000 A4=1.54046e-004 A6=-1.65834e-006 A8=-4.30312e-008 A10=3.85331e-010
Side 8
K=-5.65588e+000 A4=7.37605e-004 A6=-1.02719e-005 A8=6.14376e-008 A10=-1.34191e-010
Side 10
K=-7.64153e-001 A4=3.04449e-005 A6=-4.75055e-007 A8=4.20704e-009 A10=-1.22627e-011

variable interval
0m-1 -1 -5 +2
d4 2.55 2.19 1.07 3.23
d10 1.30 1.65 2.78 0.62


[Numerical Example 2]
At standard diopter focal length f=17.3 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.00
3 ∞ 8.50 1.83400 37.2
4 ∞ (variable)
5 32.488 6.22 1.85135 40.1
6* -14.808 3.68
7* -6.818 1.42 1.65100 21.5
8* -112.547 0.15
9 131.272 6.37 1.85135 40.1
10* -13.950 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-5.17963e-001 A4=1.31147e-004 A6=-9.49493e-007 A8=7.11126e-009 A10=-2.06714e-011
Side 7
K=-2.30355e+000 A4=-4.79553e-005 A6=-4.11730e-007 A8=4.18329e-009 A10=-9.10282e-012
Side 8
K=-2.29196e+002 A4=9.77074e-005 A6=-6.23395e-007 A8=-5.31801e-011 A10=6.30220e-012
Side 10
K=-2.73927e+000 A4=-4.98063e-006 A6=-4.94289e-007 A8=4.69850e-009 A10=-1.20091e-011

variable interval
0m-1 -1 -5 +2
d4 2.68 2.43 1.07 3.61
d10 2.61 3.01 4.29 1.44


[Numerical Example 3]
Standard diopter focal length f=16.8 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 8.50 1.83400 37.2
4 ∞ (variable)
5 26.024 8.71 1.88300 40.8
6* -14.196 3.86
7* -5.853 1.47 1.65100 21.5
8* -155.941 0.20
9 83.161 5.34 1.88300 40.8
10* -14.454 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-7.60898e-001 A4=1.36460e-004 A6=-4.63831e-007 A8=8.36850e-010 A10=2.95605e-013
Side 7
K=-1.99999e+000 A4=2.21098e-004 A6=-2.77198e-006 A8=1.49452e-008 A10=-2.84912e-011
Side 8
K=1.02092e+001 A4=1.52192e-004 A6=-6.32505e-007 A8=-8.14858e-010 A10=2.51890e-012
Side 10
K=-3.81974e+000 A4= 5.47872e-005 A6=-1.08397e-006 A8=7.13369e-009 A10=-9.99804e-012

variable interval
0m-1 -1 -5 +2
d4 2.62 2.38 1.07 3.49
d10 2.61 3.01 4.29 1.44


[Numerical Example 4]
At standard diopter focal length f=20.9 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 11.00 1.51633 64.1
4 ∞ (variable)
5 70.050 5.00 1.53500 55.7
6* -10.453 2.24
7* -8.090 1.47 1.63550 23.9
8* -30.489 0.20
9 565.772 5.30 1.53500 55.7
10* -11.482 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-1.14236e+000 A4=7.88210e-005 A6=-6.98908e-007 A8=6.72781e-009 A10=3.25984e-011
Side 7
K=-7.73767e-001 A4=-1.65804e-004 A6=3.40985e-006 A8=-5.33102e-008 A10=4.56325e-010
Side 8
K=1.10047e+000 A4=-1.61563e-004 A6=1.59586e-006 A8=-2.23675e-008 A10=1.59401e-010
Side 10
K=-5.64372e-001 A4=2.41444e-005 A6=9.78734e-007 A8=-3.91803e-009 A10=-1.07217e-011

variable interval
0m-1 -1 -5 +2
d4 2.80 2.44 1.07 3.97
d10 2.61 3.01 4.29 1.44


[Numerical Example 5]
Standard diopter focal length f=19.4 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 5.50 1.83400 37.2
4 ∞ (variable)
5 53.212 4.23 1.76802 49.2
6* -17.471 3.64
7* -6.264 1.47 1.63550 23.9
8* -17.286 0.20
9 -978.513 6.33 1.76802 49.2
10* -13.131 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-1.77022e-001 A4=1.46611e-005 A6=-2.33559e-007 A8=8.98377e-009 A10=-4.50295e-011
Side 7
K=-1.48356e+000 A4=3.08907e-005 A6=-2.68254e-006 A8=2.86950e-008 A10=-1.19054e-010
Side 8
K=-1.00098e+001 A4=1.17321e-004 A6=-1.03184e-006 A8=1.13551e-009 A10=2.52839e-011
Side 10
K=-8.57586e-001 A4=2.88196e-005 A6=-4.48100e-007 A8=4.84736e-009 A10=-2.05834e-011

variable interval
0m-1 -1 -5 +2
d4 4.60 4.24 2.92 5.72
d10 2.61 3.01 4.29 1.44


[Numerical Example 6]
At standard diopter focal length f=17.3 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 1.40
3 ∞ 7.50 1.83400 37.2
4 ∞ (variable)
5 38.725 6.19 1.76802 49.2
6* -12.483 3.78
7* -6.314 1.47 1.63550 23.9
8* -36.874 0.20
9 142.426 6.67 1.76802 49.2
10* -12.969 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-6.29498e-001 A4=1.19468e-004 A6=-4.49758e-007 A8=8.06285e-010 A10=4.56492e-012
Side 7
K=-1.47340e+000 A4=1.85691e-004 A6=-3.51354e-006 A8=1.54064e-008 A10=-3.68192e-012
Side 8
K=-9.42027e+000 A4=1.27913e-004 A6=-9.21440e-007 A8=-2.65348e-010 A10=7.48724e-012
Side 10
K=-1.26617e+000 A4=6.28629e-005 A6=-9.49756e-007 A8=6.89539e-009 A10=-1.46285e-011

variable interval
0m-1 -1 -5 +2
d4 2.68 2.43 1.07 3.61
d10 2.61 3.01 4.29 1.44


[Numerical Example 7]
At standard diopter focal length f=18.7 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 7.50 1.83400 37.2
4 ∞ (variable)
5 57.475 4.45 1.76802 49.2
6* -14.399 3.52
7* -5.527 2.20 1.63550 23.9
8* -16.114 0.15
9 189.354 6.00 1.76802 49.2
10* -13.731 (variable)
11 ∞ 1.00 1.49171 57.4
12 ∞ 23.00
13 (eye point)

Aspheric data 6th surface
K=-6.90825e-001 A4=8.38523e-005 A6=-6.11664e-007 A8=7.67392e-009 A10=-4.11453e-011
Side 7
K=-1.90508e+000 A4=3.96382e-005 A6=-1.65188e-006 A8=-8.19135e-009 A10=9.04048e-011
Side 8
K=-7.66349e+000 A4=2.88263e-004 A6=-3.08349e-006 A8=1.31547e-008 A10=-1.74846e-011
Side 10
K=-1.83793e+000 A4=-1.51567e-005 A6=-4.27702e-007 A8=4.02270e-009 A10=-1.15184e-011

variable interval
0m-1 -1 -5 +2
d4 2.72 2.37 1.07 3.55
d10 1.45 1.80 3.09 0.62


[Numerical Example 8]
Standard diopter focal length f=18.0 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 8.50 1.83400 37.2
4 ∞ (variable)
5 40.554 6.57 1.88202 37.2
6* -12.558 3.10
7* -5.890 1.50 1.65100 21.5
8* -39.891 0.30
9 48.918 6.09 1.53100 56.0
10* -12.308 0.40
11* -38.395 1.80 1.53100 56.0
12 -26.328 (variable)
13 ∞ 1.00 1.49171 57.4
14 ∞ 23.00
15 (eye point)

Aspheric data 6th surface
K=-7.45019e-001 A4=1.16677e-004 A6=-1.85865e-007 A8=-1.32382e-009 A10=6.82375e-012
Side 7
K=-1.38352e+000 A4=3.55229e-004 A6=-3.42042e-006 A8=1.38479e-008 A10=-1.92068e-011
Side 8
K=-3.54676e+000 A4=1.04902e-004 A6=-4.85409e-007 A8=-6.62833e-010 A10=3.65795e-012
Side 10
K=-2.66672e+000 A4=1.00347e-004 A6=-9.85461e-007 A8=5.19498e-009 A10=-8.12637e-012
Page 11
K=0.00000e+000 A4=1.98485e-009 A6=1.66569e-008 A8=-2.97303e-010

variable interval
0m-1 -1 -5 +2
d4 2.75 2.50 1.07 3.77
d12 2.61 3.01 4.29 1.44


[Numerical Example 9]
At standard diopter focal length f=17.1 pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 8.00 1.83400 37.2
4 ∞ (variable)
5 27.859 9.33 1.85000 40.0
6* -13.571 3.46
7* -5.638 1.47 1.65100 21.5
8* -24.363 0.30
9 38.822 5.44 1.53100 56.0
10* -13.850 0.38
11* 36.543 1.49 1.53100 56.0
12 66.561 (variable)
13 ∞ 1.00 1.49171 57.4
14 ∞ 23.00
15 (eye point)

Aspheric data 6th surface
K=-6.90393e-001 A4=7.11450e-005 A6=8.55692e-008 A8=-9.79932e-010 A10=2.64450e-012
Side 7
K=-1.84620e+000 A4=7.27865e-005 A6=-4.88666e-007 A8=2.40798e-009 A10=-4.18506e-012
Side 8
K=-1.55919e+001 A4=3.12901e-005 A6=-3.51296e-008 A8=-6.43786e-010 A10=2.29239e-012
Side 10
K=-8.02388e+000 A4=3.24660e-006 A6=3.54142e-008 A8=3.14412e-010 A10=2.92609e-012
Page 11
K=0.00000e+000 A4=-3.28708e-005 A6=-1.57784e-008 A8=1.21101e-009

variable interval
0m-1 -1 -5 +2
d4 2.66 2.43 1.07 3.57
d12 2.61 3.01 4.29 1.44


[Numerical Example 10]
At standard diopter focal length f=16.7 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 8.00 1.83400 37.2
4 ∞ (variable)
5 26.560 9.25 1.85135 40.1
6* -11.463 2.78
7* -5.419 1.48 1.65100 21.5
8* -559.787 0.30
9 64.096 4.96 1.85135 40.1
10* -16.116 0.38
11* -330.547 1.50 1.85135 40.1
12 -87.784 (variable)
13 ∞ 1.00 1.49171 57.4
14 ∞ 23.00
15 (eye point)

Aspheric data 6th surface
K=-8.96739e-001 A4=1.40579e-004 A6=-1.40304e-007 A8=-1.20332e-009 A10=4.37568e-012
Side 7
K=-1.72726e+000 A4=2.86825e-004 A6=-2.54542e-006 A8=1.07202e-008 A10=-1.64392e-011
Side 8
K=-2.00703e+001 A4=7.06128e-005 A6=-2.04709e-007 A8=1.03566e-010 A10=7.04374e-013
Side 10
K=-4.88826e+000 A4=1.02869e-004 A6=-1.00942e-006 A8=3.92627e-009 A10=-3.22191e-012
Page 11
K=0.00000e+000 A4=1.40836e-009 A6=-1.47238e-007 A8=8.72409e-010

variable interval
0m-1 -1 -5 +2
d4 2.60 2.36 1.07 3.46
d12 2.61 3.01 4.29 1.44


[Numerical Example 11]
At standard diopter focal length f=19.6 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.00
3 ∞ 15.00 1.83400 37.2
4 ∞ (variable)
5 26.960 6.81 1.88202 37.2
6* -20.302 4.41
7* -6.551 1.50 1.65100 21.5
8* -49.760 0.30
9 31.260 4.87 1.53100 56.0
10* -13.846 0.40
11* -316.353 1.50 1.53100 56.0
12 -60.253 (variable)
13 ∞ 1.00 1.49171 57.4
14 ∞ 23.00
15 (eye point)

Aspheric data 6th surface
K=-3.30456e-001 A4=6.13001e-005 A6=-7.08532e-008 A8=-8.15267e-010 A10=5.59645e-012
Side 7
K=-1.31789e+000 A4=3.64324e-004 A6=-3.19790e-006 A8=1.52536e-008 A10=-2.50693e-011
Side 8
K=7.74508e+000 A4=8.92913e-005 A6=-5.69190e-007 A8=-4.29620e-010 A10=1.40568e-011
Side 10
K=-4.27201e+000 A4=1.60683e-004 A6=-8.25502e-007 A8=4.85238e-009 A10=-2.05050e-011
Page 11
K=0.00000e+000 A4=1.26889e-010 A6=-3.88095e-008 A8=-1.50250e-009

variable interval
0m-1 -1 -5 +2
d4 2.76 2.39 1.07 3.88
d12 2.61 3.01 4.29 1.44


[Numerical Example 12]
Standard diopter focal length f=16.8 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 1.80
3 ∞ 6.00 1.83400 37.2
4 ∞ (variable)
5 26.651 10.55 1.85135 40.1
6* -11.573 3.10
7* -5.936 1.50 1.65100 21.5
8* 1804.804 0.31
9 85.698 5.84 1.85135 40.1
10* -17.409 0.40
11* -84.257 1.65 1.85135 40.1
12 -39.309 (variable)
13 ∞ 1.00 1.49171 57.4
14 ∞ 23.00
15 (eye point)

Aspheric data 6th surface
K=-7.94087e-001 A4=1.43667e-004 A6=-1.50861e-007 A8=-1.21274e-009 A10=5.78175e-012
Side 7
K=-1.66348e+000 A4=2.78452e-004 A6=-2.82867e-006 A8=1.24634e-008 A10=-1.96980e-011
Side 8
K=-1.98339e+001 A4=1.11687e-004 A6=-6.29175e-007 A8=6.08744e-010 A10=2.01111e-012
Side 10
K=-3.25040e+000 A4=7.08690e-005 A6=-9.12462e-007 A8=4.69644e-009 A10=-8.75924e-012
Page 11
K=0.00000e+000 A4=5.18866e-009 A6=-1.31993e-007 A8=6.48056e-011

variable interval
0m-1 -1 -5 +2
d4 2.63 2.39 1.07 3.50
d12 2.61 3.01 4.29 1.44


[Numerical Example 13]
Standard diopter focal length f=19.4 Pupil diameter 10
Screen display diagonal length 6.434

Surface data surface number rd nd νd
1 ∞ 0.70 1.52100 65.1
2 ∞ 2.40
3 ∞ 5.50 1.83400 37.2
4 ∞ (variable)
5 80.942 4.31 1.76802 49.2
6* -17.118 3.84
7* -7.014 1.50 1.63550 23.9
8* -29.619 0.30
9 33.202 6.80 1.53500 55.7
10* -12.491 0.40
11* -231.468 2.20 1.53500 55.7
12 -38.773 (variable)
13 ∞ 1.00 1.49171 57.4
14 ∞ 23.00
15 (eye point)

Aspheric data 6th surface
K=-3.40902e-001 A4=-8.45938e-006 A6=-7.30356e-007 A8=1.19537e-008 A10=-4.78498e-011
Side 7
K=-8.34256e-001 A4=-3.07734e-005 A6=-5.02200e-007 A8=1.44453e-008 A10=-2.23447e-011
Side 8
K=1.61326e+000 A4=9.82052e-005 A6=-8.14780e-007 A8=-4.37799e-009 A10=4.12233e-011
Side 10
K=-9.02152e-001 A4=4.56397e-005 A6=1.40184e-007 A8=4.52440e-009 A10=-2.34725e-011
Page 11
K=0.00000e+000 A4=3.05411e-010 A6=8.29368e-011 A8=-1.89591e-010

variable interval
0m-1 -1 -5 +2
d4 2.76 2.40 1.07 3.87
d12 2.61 3.01 4.29 1.44

Table 1 below shows numerical values corresponding to conditional expressions (1) to (12) in each example.

(imaging device)
Next, an embodiment of a video camera (imaging device) using the eyepiece optical system as shown in each example will be described using FIG. 27.

In FIG. 27, 10 is a video camera body, 11 is an imaging optical system that forms a subject image on an image sensor (not shown), and 12 is a sound collection microphone. Reference numeral 13 denotes an observation device (electronic viewfinder) for observing a subject image (image) displayed on a display element (not shown) via the eyepiece optical system of the present invention. The display element is constituted by a liquid crystal panel or the like, and the object formed by the photographing optical system 11 is displayed on the display element.

As described above, by applying the eyepiece optical system of the present invention to an imaging device such as a video camera, it is possible to satisfy a wide viewing angle while ensuring sufficient space for arranging the optical path branching means in the eyepiece optical system. Therefore, it is possible to obtain an imaging device having an eyepiece optical system that can sufficiently correct various aberrations such as field curvature and astigmatism. Note that the eyepiece optical system of the present invention is not limited to a video camera as shown in FIG. 27, but can also be used for, for example, a mirrorless camera with interchangeable lenses.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

L1 First lens L2 Second lens L3 Third lens

Claims (21)

arranged in order from the display element side to the viewer side,
a first lens with positive refractive power;
a second lens with negative refractive power;
An eyepiece optical system having a third lens with positive refractive power,
A maximum image height of the display element is H, a focal length of the eyepiece optical system at standard diopter is f, a focal length of the second lens is f2, and a lens on the display element side of the first lens from the display element. When the distance on the optical axis to the surface is skd,
0.300<H/f<0.400
0.300<H/skd<0.600
-0.90<f2/f<-0.45
An eyepiece optical system characterized by satisfying the following conditions. When the focal length of the first lens is f1,
0.55<f1/f<1.00
The eyepiece optical system according to claim 1, wherein the eyepiece optical system satisfies the following conditions. arranged in order from the display element side to the viewer side,
a first lens with positive refractive power;
a second lens with negative refractive power;
An eyepiece optical system having a third lens with positive refractive power,
A maximum image height of the display element is H, a focal length of the eyepiece optical system at standard diopter is f, a focal length of the first lens is f1, and a lens on the display element side of the first lens from the display element. When the distance on the optical axis to the surface is skd,
0.300<H/f<0.400
0.300<H/skd<0.600
0.55<f1/f<1.00
An eyepiece optical system characterized by satisfying the following conditions. When the focal length of the first lens is f1 and the focal length of the third lens is f3,
0.70<f3/f1<1.60
The eyepiece optical system according to any one of claims 1 to 3, characterized in that the eyepiece optical system satisfies the following conditions. The eyepiece optical system according to claim 4 , wherein the lenses included in the eyepiece optical system are only the first lens, the second lens, and the third lens. further comprising a fourth lens on the observer side of the third lens,
When the focal length of the first lens is f1, and the combined focal length of the third lens and the fourth lens is f34,
0.70<f34/f1<1.60
The eyepiece optical system according to claim 1 , wherein the eyepiece optical system satisfies the following conditions. The eyepiece optical system according to claim 6 , wherein the lenses included in the eyepiece optical system are only the first lens, the second lens, the third lens, and the fourth lens. When the refractive index of the first lens is Nd1,
1.50<Nd1
The eyepiece optical system according to any one of claims 1 to 7, wherein the eyepiece optical system satisfies the following conditions. When the refractive index of the second lens is Nd2,
1.60<Nd2
The eyepiece optical system according to any one of claims 1 to 8, characterized in that the eyepiece optical system satisfies the following conditions. When the refractive index of the third lens is Nd3,
1.50<Nd3
The eyepiece optical system according to any one of claims 1 to 9, characterized in that the eyepiece optical system satisfies the following conditions. When the radius of curvature of the second lens on the display element side and the radius of curvature on the viewer side are respectively L2R1 and L2R2,
-4.00<(L2R1+L2R2)/(L2R1-L2R2)<-0.90
The eyepiece optical system according to any one of claims 1 to 10, characterized in that the eyepiece optical system satisfies the following conditions. arranged in order from the display element side to the viewer side,
a first lens with positive refractive power;
a second lens with negative refractive power;
An eyepiece optical system having a third lens with positive refractive power,
The maximum image height of the display element is H, the focal length of the eyepiece optical system at standard diopter is f, and the distance on the optical axis from the display element to the lens surface of the first lens on the display element side is skd. , when the radius of curvature of the second lens on the display element side and the radius of curvature on the viewer side are L2R1 and L2R2, respectively,
0.300<H/f<0.400
0.300<H/skd<0.600
-4.00<(L2R1+L2R2)/(L2R1-L2R2)<-0.90
An eyepiece optical system characterized by satisfying the following conditions. When the focal length of the first lens is f1, the focal length of the second lens is f2, and the focal length of the third lens is f3,
0.60<(f1/f+|f2|/f+f3/f)/3<0.95
The eyepiece optical system according to any one of claims 1 to 12 , characterized in that the eyepiece optical system satisfies the following conditions. arranged in order from the display element side to the viewer side,
a first lens with positive refractive power;
a second lens with negative refractive power;
An eyepiece optical system having a third lens with positive refractive power,
The maximum image height of the display element is H, the focal length of the eyepiece optical system at standard diopter is f, the focal length of the first lens is f1, the focal length of the second lens is f2, and the focal length of the third lens is When the focal length is f3 and the distance on the optical axis from the display element to the lens surface of the first lens on the display element side is skd,
0.300<H/f<0.400
0.300<H/skd<0.600
0.60<(f1/f+|f2|/f+f3/f)/3<0.95
An eyepiece optical system characterized by satisfying the following conditions. When the radius of curvature of the first lens on the display element side is L1R1,
1.0<L1R1/f<4.5
The eyepiece optical system according to any one of claims 1 to 14 , characterized in that the eyepiece optical system satisfies the following conditions. When the radius of curvature of the third lens on the observer side is L3R2,
-1.10<L3R2/f<-0.50
The eyepiece optical system according to any one of claims 1 to 15 , characterized in that the eyepiece optical system satisfies the following conditions. arranged in order from the display element side to the viewer side,
a first lens with positive refractive power;
a second lens with negative refractive power;
An eyepiece optical system having a third lens with positive refractive power,
The maximum image height of the display element is H, the focal length of the eyepiece optical system at standard diopter is f, and the distance on the optical axis from the display element to the lens surface of the first lens on the display element side is skd. , when the radius of curvature of the third lens on the observer side is L3R2,
0.300<H/f<0.400
0.300<H/skd<0.600
-1.10<L3R2/f<-0.50
An eyepiece optical system characterized by satisfying the following conditions. The eyepiece optical system according to any one of claims 1 to 17 , further comprising an optical path branching means disposed between the display element and the first lens. The eyepiece optical system according to claim 18 , wherein the optical path branching means is a dichroic prism. The eyepiece optical system according to any one of claims 1 to 19 , further comprising the display element disposed on the display element side of the first lens. An image sensor and
an imaging optical system that forms a subject image on the image sensor;
a display element that displays the subject image;
An imaging device comprising: the eyepiece optical system according to any one of claims 1 to 19 , which is used to observe an image displayed on the display element.