WO2019054359A1

WO2019054359A1 - Eyepiece optical system, optical device, and method for producing eyepiece optical system

Info

Publication number: WO2019054359A1
Application number: PCT/JP2018/033570
Authority: WO
Inventors: 歩槇田
Original assignee: 株式会社ニコン
Priority date: 2017-09-15
Filing date: 2018-09-11
Publication date: 2019-03-21
Also published as: JPWO2019054359A1; JP2023083485A; JP7280561B2; JP7037730B2; JP2022066386A

Abstract

Provided are: an eyepiece optical system EL having favorable optical performance and a high observation magnification power; an optical device having this eyepiece optical system EL; and a method for producing an eyepiece optical system EL. This eyepiece optical system EL satisfies the following conditional expression, and has, in order from the observation object side: a first lens component having a positive refractive power; a second lens component having a negative refractive power; a third lens component having a positive refractive power; and a fourth lens component having a positive refractive power. 1.38<fe/f1<3.00; fe is the focal distance of the entire eyepiece optical system EL; f1 is the focal distance of the first lens component G1; and a "lens component" refers to a single lens or a cemented lens.

Description

Eyepiece optical system, optical apparatus, and method of manufacturing eyepiece optical system

The present invention relates to an eyepiece optical system, an optical device, and a method of manufacturing the eyepiece optical system.

Conventionally, an eyepiece optical system having high imaging performance has been proposed (see, for example, Patent Document 1). However, Patent Document 1 has a problem that further improvement in optical performance is required.

JP, 2015-075713, A

The eyepiece optical system according to the first aspect of the present invention has a first lens component having a positive refractive power, a second lens component having a negative refractive power, and a positive refractive power in order from the observation object side. A third lens component and a fourth lens component having a positive refractive power are satisfied, and the condition of the following expression is satisfied.
1.38 <fe / f1 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f1: focal length of the first lens component "lens component" means a single lens or a cemented lens.

In the eyepiece optical system according to the second aspect of the present invention, a first lens component having a positive refractive power, a second lens component having a negative refractive power, and a positive refractive power are sequentially arranged from an observation object side. And a fourth lens component having a positive refractive power, and the condition of the following equation is satisfied.
0.48 <fe / f12 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f12: combined focal length of the first lens component and the second lens component "lens component" means a single lens or a cemented lens.

Further, in the manufacturing method of the eyepiece optical system according to the first aspect of the present invention, the first lens component having positive refractive power, the second lens component having negative refractive power, and the positive lens component in order from the observation object side It is a manufacturing method of the eyepiece optical system which has the 3rd lens component which has the following, and the 4th lens component which has positive refractive power, and it arranges so that the conditions of a following formula may be satisfied.
1.38 <fe / f1 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f1: focal length of the first lens component "lens component" means a single lens or a cemented lens.

Further, in the method of manufacturing an eyepiece optical system according to the second aspect of the present invention, a first lens component having positive refractive power, a second lens component having negative refractive power, and a positive lens component in order from the observation object side It is a manufacturing method of the eyepiece optical system which has the 3rd lens component which has the following, and the 4th lens component which has positive refractive power, and it arranges so that the conditions of a following formula may be satisfied.
0.48 <fe / f12 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f12: combined focal length of the first lens component and the second lens component "lens component" means a single lens or a cemented lens.

It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 1st Example. FIG. 5 shows various aberrations of the eyepiece optical system according to the first example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 2nd Example. FIG. 7 shows various aberrations that occurred in the eyepiece optical system according to the second example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 3rd Example. FIG. 7 shows various aberrations that occurred in the eyepiece optical system according to the third example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 4th Example. FIG. 7 shows various aberrations that occurred in the eyepiece optical system according to the fourth example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 5th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the fifth example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 6th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the sixth example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 7th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the seventh example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 8th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the eighth example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 9th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the ninth example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 10th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the tenth example. It is sectional drawing which shows the lens structure of the eyepiece optical system which concerns on 11th Example. FIG. 21 shows various aberrations that occur in the eyepiece optical system according to the eleventh example. It is a sectional view of a camera which carries the above-mentioned eyepiece optical system. It is a flowchart for demonstrating the manufacturing method of the said eyepiece optical system.

Hereinafter, preferred embodiments will be described with reference to the drawings. As shown in FIG. 1, the eyepiece optical system EL according to this embodiment includes, in order from an observation object side (also simply referred to as “object”), a first lens component G1 having positive refractive power and negative refractive power. And a third lens component G3 having a positive refractive power, and a fourth lens component G4 having a positive refractive power.

The term "lens component" refers to a single lens or a cemented lens. Also, "lens element" refers to each lens constituting a single lens or a cemented lens. Also, the “reference diopter” refers to a diopter of −1 [1 / m]. Here, with regard to the unit [1 / m], diopter X [1 / m] is a state in which the image by the eyepiece optical system EL can be positioned at 1 / X [m (meters)] on the optical axis from the eye point (The sign is positive when the image is formed closer to the observer (eye point side) than the eyepiece optical system EL).

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (1) shown below.

1.38 <fe / f1 <3.00 (1)
However,
fe: focal length of the entire eyepiece optical system EL f1: focal length of the first lens component G1

Conditional expression (1) defines the refractive power of the first lens component G1 closest to the object to be observed, in order to intensify the total refractive power of the eyepiece optical system EL while maintaining good spherical aberration and coma aberration. It is. In the above-described eyepiece optical system EL having a positive, negative, positive, or positive refractive power arrangement from the observation object side, the first lens component G1 closest to the observation object side has the least influence on spherical aberration and coma. Although the first lens component G1 greatly affects the deterioration of the field curvature, the field curvature generated by the positive refractive power of the first lens component G1 may be corrected by the negative refractive power of the second lens component G2. It is possible. Therefore, in order to increase the observation magnification of the eyepiece optical system EL while maintaining good spherical aberration and coma aberration, it is necessary to give the first lens component G1 closest to the observation object a strong positive refractive power. . Below the lower limit of this conditional expression (1), the positive refractive power of the first lens component G1 closest to the observation object becomes weak, the refractive power of the entire eyepiece optical system EL becomes weak, and the observation magnification is increased. Is not preferable because it becomes difficult. In order to secure the effect of the conditional expression (1), it is more desirable to set the lower limit value of the conditional expression (1) to 1.45, further 1.48 and further 1.50. If the upper limit value of the conditional expression (1) is exceeded, the positive refractive power of the first lens component G1 closest to the observation object becomes strong, and the curvature of field generated in the first lens component G1 becomes large. The curvature of field can not be completely corrected by the lens component G2, which is not preferable. In order to secure the effect of the conditional expression (1), it is more desirable to set the upper limit value of the conditional expression (1) to 2.00, further preferably 1.65.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (2) shown below.

0.48 <fe / f12 <3.00 (2)
However,
fe: Focal length of the whole system of the eyepiece optical system EL f12: Synthetic focal length of the first lens component G1 and the second lens component G2

Conditional expression (2) defines the combined refractive power of the first lens component G1 and the second lens component G2 in order to increase the observation magnification and correct the field curvature well. The refractive power of the first lens component G1 and the refractive power of the second lens component G2 greatly affect correction and generation of curvature of field. In order not to generate field curvature, it is desirable to weaken the combined refractive power of the first lens component G1 and the second lens component G2. However, if the combined refractive power of the first lens component G1 and the second lens component G2 is weakened, the refractive power of the entire eyepiece optical system EL is weakened, and it becomes difficult to increase the observation magnification. In addition, the combined refractive power of the first lens component G1 and the second lens component G2 is weak, and if the observation magnification is increased excessively, the refractive powers of the third lens component G3 and the fourth lens component G4 become strong, and spherical aberration , Worsen coma. If the lower limit value of the conditional expression (2) is not reached, the synthetic refractive power of the first lens component G1 and the second lens component G2 becomes weak, and the observation magnification can not be increased. In addition, if the observation magnification is increased while the value is below the lower limit value of the conditional expression (2), the spherical aberration and the coma aberration are unfavorably deteriorated. In order to secure the effect of the conditional expression (2), it is more desirable to set the lower limit value of the conditional expression (2) to 0.48, further 0.50, and further 0.55. If the upper limit value of the conditional expression (2) is exceeded, the combined refractive power of the first lens component G1 and the second lens component G2 becomes strong, and curvature of field occurs, which is not preferable. In order to secure the effect of the conditional expression (2), it is more desirable to set the upper limit value of the conditional expression (2) to 1.00 and further to 0.70.

Further, in the eyepiece optical system EL according to the present embodiment, when the lens surface on the eye point side of the lens closest to the eye point is made convex to the eye point side, the light ray near the center of the observation object is the most eye The emission angle from the lens surface on the eye point side of the lens on the point side becomes small, and the amount of generation of spherical aberration can be suppressed. On the other hand, the exit angle of the light beam in the peripheral portion of the screen can be increased, and the coma aberration can be corrected.

Further, in the eyepiece optical system EL according to the present embodiment, it is desirable that at least one of the lens elements constituting the second lens component G2 satisfy the conditional expression (3) shown below.

15.0 <d d2 <35.0 (3)
However,
d d 2: Abbe number for the d-line of the medium of the lens element constituting the second lens component G 2

Conditional expression (3) defines the Abbe number of the lens element having the strongest negative refractive power among the lens elements constituting the second lens component G2 in order to correct the lateral chromatic aberration well. In particular, when the combined refractive power of the first lens component G1 and the second lens component G2 is made to have strong positive refractive power so as to satisfy the conditional expression (2) described above, the negative refractive power of the second lens component G2 is The power is smaller. Therefore, by increasing the dispersion of the lens element having the most negative refractive power among the second lens component G2, the lateral chromatic aberration can be corrected well even with the negative refractive power of the weak second lens component G2. . If the lower limit value of the conditional expression (3) is not reached, overcorrection of magnification chromatic aberration occurs and the magnification chromatic aberration is deteriorated. In order to secure the effect of the conditional expression (3), it is more desirable to set the lower limit value of the conditional expression (3) to 20 and further to 30. If the upper limit value of the conditional expression (3) is exceeded, it is not preferable because lateral chromatic aberration can not be corrected. In order to secure the effect of the conditional expression (3), it is desirable to set the upper limit value of the conditional expression (3) to 22.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (4) shown below.

0.01 <fe / f4 <0.33 (4)
However,
fe: Focal length of the whole system of the eyepiece optical system EL f4: Focal length of the fourth lens component G4

Conditional expression (4) defines the refractive power of the lens closest to the eye point in order to correct spherical aberration and coma aberration well. The fourth lens component G4 closest to the eye point has the largest influence on spherical aberration and coma. Therefore, if the upper limit value of the conditional expression (4) is exceeded, the positive refractive power of the fourth lens component G4 becomes strong, and the spherical aberration and the coma aberration are largely deteriorated. In order to secure the effect of the conditional expression (4), it is more desirable to set the upper limit value of the conditional expression (4) to 0.30, further 0.25, further 0.239. If the lower limit value of the conditional expression (4) is not reached, it is difficult to intensify the refractive power (power) of the entire eyepiece optical system EL, and it is not preferable because the observation magnification can not be increased. Assuming that the refractive power of the fourth lens component G4 falls below the lower limit value of the conditional expression (4) and the observation magnification is increased, the positive refractive powers of the first lens component G1 and the third lens component G3 become extreme. Correction of curvature of field becomes difficult as the second lens component G2 becomes stronger or the negative refractive power of the second lens component G2 becomes weaker. In order to secure the effect of the conditional expression (4), it is more desirable to set the lower limit value of the conditional expression (4) to 0.10, further preferably 0.15.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (5) shown below.

-0.30 <(G2R2-G3R1) / (G2R2 + G3R1) <0.50 (5)
However,
G2R2: curvature radius of lens surface of second lens component G2 closest to eye point G3R1: curvature radius of lens surface of third lens component G3 closest to observation object

Conditional expression (5) defines the shape of the lens surface on the most eye point side of the second lens component G2 and the shape of the lens surface on the most observation object side of the third lens component G3 in order to correct coma aberration well. It is a thing. The lens surface closest to the eye point of the second lens component G2 and the lens surface closest to the observation object of the third lens component G3 greatly affect the generation or correction of coma. In order to correct coma aberration favorably, it is preferable to correct coma aberration generated on the lens surface closest to the eye point of the second lens component G2 with the lens surface closest to the observation object of the third lens component G3. In order to correct coma well, the shape of the lens surface on the most eye point side of the second lens component G2 and the shape of the lens surface on the most observation object side of the third lens component G3 are made similar. It is desirable to make coma aberration generated on the lens surface closest to the eye point of the two lens component G2 similar to coma aberration corrected on the lens surface closest to the observation object on the third lens component G3 to cancel coma aberration. Below the lower limit value of the conditional expression (5), the similarity between the shape of the lens surface on the most eye point side of the second lens component G2 and the shape of the lens surface on the most observation object side of the third lens component G3 collapses. It is not preferable because coma aberration occurs. In order to secure the effect of the conditional expression (5), it is desirable to set the lower limit value of the conditional expression (5) to −0.25. Further, when the upper limit value of the conditional expression (5) is exceeded, the similarity between the shape of the lens surface on the most eye point side of the second lens component G2 and the shape of the lens surface on the most observation object side of the third lens component G3 It is not preferable because it collapses and coma aberration occurs. In order to secure the effect of the conditional expression (5), it is more desirable to set the upper limit value of the conditional expression (5) to 0.25, further to −0.20.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (6) shown below.

-0.75 <(G1R2 + G1R1) / (G1R2-G1R1) <0.00 (6)
However,
G1R1: The radius of curvature of the lens surface of the first lens component G1 closest to the observation object G1R2: The radius of curvature of the lens surface closest to the eye point of the first lens component G1

Conditional expression (6) defines the shape of the first lens component G1 in order to increase the observation magnification and correct the curvature of field and distortion well. The positive refractive power of the first lens component G1 generates a curvature of field, but the curvature of field generated by the negative refractive power of the second lens component G2 is corrected. If the refractive power of the lens surface closest to the eye point of the first lens component G1 is increased, the field curvature generated by the first lens component G1 becomes large, and the negative refractive power of the second lens component G2 is sufficient to correct It disappears. On the other hand, in order to increase the observation magnification, it is necessary to increase the positive refractive power of the first lens component G1. Therefore, the positive refractive power of the lens surface closest to the observation object of the first lens component G1 should be You have to make it bigger. However, if the positive refracting power of the lens surface closest to the observation object of the first lens component G1 is increased too much, distortion will be aggravated. If the upper limit value of the conditional expression (6) is exceeded, the refractive power of the first lens component G1 becomes too large, and the distortion is aggravated, which is not preferable. In order to secure the effect of the conditional expression (6), it is more desirable to set the upper limit value of the conditional expression (6) to −0.20, further preferably −0.30. If the lower limit value of the conditional expression (6) is not reached, the refractive power of the first lens component G1 becomes weak, and the observation magnification can not be increased. In addition, if the observation magnification is increased while the lower limit value of conditional expression (6) is exceeded, the refractive power of the lens surface closest to the eye point of the first lens component G1 increases, and the field curvature is degraded. Not desirable. In order to secure the effect of the conditional expression (6), it is more desirable to set the lower limit value of the conditional expression (6) to −0.57, further −0.56, and further −0.50.

The eyepiece optical system EL according to the present embodiment can correct distortion by setting the lens surface closest to the observation object of the first lens component G1 to be rotationally symmetric aspheric, so that the first lens component G1 can be corrected. This makes it possible to strengthen the refractive power of the lens surface closest to the observation object, which is advantageous for increasing the observation magnification.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (7) shown below.

-1.00 <fe / EnP <-0.48 (7)
However,
fe: Focal length of the whole system of the eyepiece optical system EL: Entrance pupil position of the eyepiece optical system EL at a reference diopter (the code is positive on the eye point side with respect to the surface of the observation object)

Conditional expression (7) defines the entrance pupil position in order to increase the observation magnification while keeping the eye point long. By increasing the passing height of the chief ray of high image height in a region close to the observation object plane, it becomes easy to increase the observation magnification while keeping the eye point long. In order to increase the passing height of the chief ray having a high image height in a region close to the observation object plane, it is effective to set the entrance pupil distance to a near distance opposite to the eye point side from the observation object plane. If the upper limit value of the conditional expression (7) is exceeded, the entrance pupil position is separated from the observation object, and it is not possible to increase the passing height of the chief ray of high image height. It is not preferable because it becomes impossible. In order to secure the effect of the conditional expression (7), it is desirable to set the upper limit value of the conditional expression (7) to −0.50. If the lower limit value of conditional expression (7) is not reached, the entrance pupil position approaches the observation object too much, so the chief ray ray passing height of the first lens component G1 at the high image height becomes high, and a large field curvature occurs. It is not preferable because it In order to secure the effect of the conditional expression (7), it is more desirable to set the lower limit value of the conditional expression (7) to −0.70, further preferably −0.65.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (8) shown below.

-0.40 <fe / f23 <-0.15 (8)
However,
fe: Focal length of the whole system of the eyepiece optical system EL f23: Synthetic focal length of the second lens component G2 and the third lens component G3

The conditional expression (8) reduces the deterioration of the aberration performance when the optical axes of the second lens component G2 and the third lens component G3 are shifted, so the second lens component G2 and the third lens component G3 It defines the ratio of the combined focal length of the above and the focal length of the entire eyepiece optical system EL. By making the combined focal length of the second lens component G2 and the third lens component G3 smaller than the focal length of the entire eyepiece optical system EL, the light of the second lens component G2 and the light of the third lens component G3 due to manufacturing errors Even when the axis deviates, the deterioration of the aberration performance can be reduced. Further, it is possible to reduce the deterioration of the optical performance when the refractive index of the second lens component G2 and the third lens component G3 or the curvature radius changes due to the temperature change. In particular, this is effective when the second lens component G2 and the third lens component G3 are made of an optical resin. If the lower limit value of the conditional expression (8) is not reached, the negative combined refractive power of the second lens component G2 and the third lens component G3 becomes strong, and the deterioration of aberration performance due to manufacturing errors becomes large, which is not preferable. In order to secure the effect of the conditional expression (8), it is desirable to set the lower limit value of the conditional expression (8) to −0.35. If the upper limit value of the conditional expression (8) is exceeded, the negative refractive power of the second lens component G2 decreases, which is not preferable because the correction of curvature of field becomes insufficient. In order to secure the effect of the conditional expression (8), it is more desirable to set the upper limit value of the conditional expression (8) to −0.20, further preferably −0.25.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (9) shown below.

0.58 <D1 / f1 <0.90 (9)
However,
D1: Air conversion distance from the observation object to the lens surface closest to the observation object of the first lens component G1 at the standard diopter f1: Focal distance of the first lens component G1

The conditional expression (9) corrects coma aberration well, so the air conversion distance from the observation object at the reference diopter to the lens surface closest to the observation object of the first lens component G1 and the focal distance of the first lens component G1 Defines the ratio of When the air conversion distance from the observation object to the lens surface closest to the observation object of the first lens component G1 at the reference diopter becomes large, the luminous flux emitted from one point on the observation surface passes high on the first lens component G1. Changes greatly. Therefore, if the air conversion distance D1 from the observation object to the lens surface closest to the observation object of the first lens component G1 becomes large, the positive refractive power of the first lens component G1 causes a large coma aberration, so the first lens component It is necessary to reduce the refractive power of G1. On the other hand, in order to increase the refractive power of the first lens component G1, in order to reduce the coma aberration generated in the first lens component G1, from the observation object to the lens surface closest to the observation object on the first lens component G1. It is necessary to reduce the air conversion distance D1 of If the upper limit value of the conditional expression (9) is exceeded, the refractive power of the first lens component G1 becomes stronger than the air conversion distance D1 from the observation object to the lens surface closest to the observation object of the first lens component G1. It is not preferable because the aberration is aggravated. In order to secure the effect of the conditional expression (9), it is more desirable to set the upper limit value of the conditional expression (9) to 0.71, further preferably 0.68. If the lower limit value of the conditional expression (9) is not reached, the positive refractive power of the first lens component G1 becomes weak, and it is not preferable because the observation magnification can not be increased. In order to secure the effect of the conditional expression (9), it is more desirable to set the lower limit value of the conditional expression (9) to 0.60 and further to 0.63.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (10) shown below. The total length of the eyepiece optical system EL is the distance on the optical axis from the observation object O to the lens surface closest to the eye point of the eyepiece optical system EL.

1.50 <TL / fe <1.80 (10)
However,
TL: total length fe of the eyepiece optical system EL: focal length of the whole system of the eyepiece optical system EL

Conditional expression (10) defines the ratio of the total length of the eyepiece optical system EL to the focal length of the entire system in order to correct the field curvature. If the lower limit value of the conditional expression (10) is not reached, it is not preferable because the refractive power of the entire eyepiece optical system EL becomes weak and the observation magnification can not be increased. In order to secure the effect of the conditional expression (10), it is more desirable to set the lower limit value of the conditional expression (10) to 1.55, further preferably 1.60. If the upper limit value of the conditional expression (10) is exceeded, the curvature of field is deteriorated. In order to secure the effect of the conditional expression (10), it is desirable to set the upper limit value of the conditional expression (10) to 1.70.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (11) shown below. When the first lens component G1 is configured of a cemented lens and has a plurality of lens elements, at least one of the lens elements satisfies the conditional expression (11).

1.550 <nd1 <1.800 (11)
However,
nd1: the refractive index to the d-line of the medium of the lens element constituting the first lens component G1

The conditional expression (11) defines the refractive index to the d-line of the medium of the lens element constituting the first lens component G1 in order to correct distortion and field curvature well. If the lower limit value of the conditional expression (11) is not reached, it is not preferable because the first lens component G1 can not have refracting power and it is difficult to maintain performance and achieve high magnification. In order to secure the effect of the conditional expression (11), it is more desirable to set the lower limit value of the conditional expression (11) to 1.600, further preferably 1.700. If the upper limit value of the conditional expression (11) is exceeded, distortion will deteriorate, which is not preferable. In order to secure the effect of the conditional expression (11), it is desirable to set the upper limit value of the conditional expression (11) to 1.850.

Moreover, as for the eyepiece optical system EL which concerns on this embodiment, it is desirable to satisfy the conditional expression (12) shown below. When the second lens component G2 is formed of a cemented lens and has a plurality of lens elements, at least one of those lens elements satisfies the conditional expression (12).

1.640 <nd2 <1.800 (9)
However,
nd2: the refractive index to the d-line of the medium of the lens element constituting the second lens component G2

The conditional expression (12) defines the refractive index to the d-line of the medium of the lens element constituting the second lens component G2 in order to correct the astigmatism well. If the lower limit value of the conditional expression (12) is not reached, the optical performance is deteriorated due to the decentering of the second lens component G2, which is not preferable. In order to secure the effect of the conditional expression (12), it is desirable to set the lower limit value of the conditional expression (12) to 1.650. If the upper limit value of the conditional expression (12) is exceeded, correction of astigmatism becomes difficult, which is not preferable. In order to secure the effect of the conditional expression (12), it is desirable to set the upper limit value of the conditional expression (12) to 1.750.

In the eyepiece optical system EL according to the present embodiment, the first lens component G1, the second lens component G2, the third lens component G3, and the fourth lens component G4 are configured as single lenses, and are configured by four single lenses. However, sufficiently good aberration performance can be achieved.

The eyepiece optical system EL according to this embodiment can easily adjust the diopter by moving the entire eyepiece optical system in the optical axis direction.

Each of the conditions and configurations described above exerts the above-described effects, and is not limited to one satisfying all the conditions and configurations, and any one of the conditions or configurations, or any one It is possible to obtain the above-described effects even if the above conditions or combinations of configurations are satisfied.

Next, a camera which is an optical apparatus provided with the eyepiece optical system EL according to the present embodiment will be described based on FIG. The camera 1 is a so-called mirrorless camera of an interchangeable lens type provided with an objective lens (shooting lens) OL. In the camera 1, light from an object (object) (not shown) is collected by the objective lens OL, and is taken on the imaging surface of the imaging unit C via an OLPF (Optical Low Pass Filter) (not shown). Form an image of the subject. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit C to generate the image of the subject. This image is displayed on an electronic view finder (EVF) provided in the camera 1. Here, the electronic view finder EVF includes an image display element DP such as a liquid crystal display element and an eyepiece optical system EL for magnifying and observing an image displayed on a display surface (the observation object O described above) of the image display element DP. And is configured. Thus, the photographer can observe the image of the object (subject) formed by the objective lens OL through the eyepiece optical system EL by positioning the eye at the eye point EP.

Further, when the photographer presses a release button (not shown), the image photoelectrically converted by the imaging unit C is stored in a memory (not shown). In this way, the photographer can shoot a subject with the main camera 1. In the present embodiment, an example of a mirrorless camera has been described, but the eyepiece optical system EL according to the present embodiment is a single-lens reflex camera having a quick return mirror in the camera body and observing a subject with a finder optical system. Even when mounted, the same effect as the camera 1 can be obtained.

Thus, the eyepiece optical system EL according to the present embodiment is an optical system (eyepiece lens) for magnifying and observing an image. Here, the image is an intermediate image by an objective lens, or a display surface of an image display element such as a liquid crystal display element or an organic EL display, and particularly preferably a display surface of an organic EL display. Therefore, the eyepiece optical system EL according to the present embodiment is used, for example, as an electronic binocular for observing an image displayed on a display surface, a head mounted display, or an eyepiece lens of an internal or external electronic viewfinder of a camera. Suitable for

Although not shown in FIG. 1 etc., an optical member such as a cover glass or a prism is provided between the observation object O (display surface of the image display element DP shown in FIG. 23) and the first lens component G1. It may be arranged. Also, an optical member such as a cover glass may be disposed between the fourth lens component G4 and the eyepoint EP.

Hereinafter, an outline of a method of manufacturing the eyepiece optical system EL according to the present embodiment will be described with reference to FIG. First, each lens is disposed, and a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, a third lens component G3 having positive refractive power, and positive refractive power A fourth lens component having a force and G4 are prepared respectively (step S100). And it arranges so that the conditions by a predetermined conditional expression (for example, conditional expression (1) mentioned above and conditional expression (2)) may be satisfied (Step S200).

Specifically, in the present embodiment, as shown in FIG. 1, for example, a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are formed in an aspheric shape in order from the observation object side. Negative meniscus lens L11 is disposed as a first lens component G1, and a lens surface on the observation object side and a lens surface on the eye point side are formed in an aspheric shape, and a negative meniscus lens shape concave on the observation object side Is arranged as a second lens component G2, and the lens surface on the observation object side and the lens surface on the eye point side are formed in an aspheric shape, and a positive meniscus lens shape having a concave surface facing the object side A positive meniscus lens in which an aspheric positive lens L31 is disposed to form a third lens component G3, the lens surface on the observation object side and the lens surface on the eye point side are aspheric and the concave surface is directed to the observation object Place the aspherical positive lens L41 Surenzu shape and the fourth lens component G4 with. The lens components thus prepared are arranged in the above-described procedure to manufacture the eyepiece optical system EL.

With the above-described configuration, it is possible to provide an eyepiece optical system EL having a large observation magnification and good optical performance, an optical apparatus having the eyepiece optical system EL, and a method of manufacturing the eyepiece optical system EL.

Hereinafter, each example of the present application will be described based on the drawings. In addition, FIG.1, FIG.3, FIG.5, FIG.7, FIG.9, FIG.11, FIG.13, FIG.15, FIG.17, FIG.19 and FIG. 21 is eyepiece optical system EL (EL1-EL11) which concerns on each Example. And the distribution of refractive power.

In these embodiments, the aspheric surface has a height in the direction perpendicular to the optical axis as y, and the distance along the optical axis from the tangent plane of the apex of each aspheric surface at height y to each aspheric surface (sag amount When S) is S (y), the radius of curvature of the reference spherical surface (paraxial radius of curvature) is r, the conic constant is K, and the nth-order aspheric coefficient is An, the following equation (a) is Ru. In the following examples, “E-n” indicates “× 10 ⁻ⁿ ”.

S (y) = (y ² / r) / {1+ (1−K × y ² / r ² ) ^1/2 }
+ A4 × y ⁴ + A6 × y ⁶ + A8 × y ⁸ + A10 × y ¹⁰ + A12 × y ¹² (a)

In each embodiment, the second-order aspheric coefficient A2 is zero. Further, in the tables of the respective embodiments, the aspheric surface is marked with * on the right side of the surface number.

[First embodiment]
FIG. 1 is a view showing the arrangement of an eyepiece optical system EL1 according to the first embodiment. The eyepiece optical system EL1 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL1, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 in the shape of a negative meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed aspheric and having a concave surface facing the observation object It is done. In the third lens component G3, the lens surface on the observation object side and the lens surface on the eye point side are formed in an aspheric shape, and the third lens component G3 is constituted by an aspheric positive lens L31 having a positive meniscus lens shape concave on the object side. ing. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL1 is performed by moving the entire eyepiece optical system EL1 in the optical axis direction.

Table 1 below presents values of specifications of the eyepiece optical system EL1. In Table 1, fe shown in the overall specifications represents the focal length of the entire system, H represents the maximum object height, and TL represents the value of the total length. The first column m in the lens data shows the order (surface number) of the lens surface from the object side along the traveling direction of the light beam, the second column r shows the radius of curvature of each lens surface, the third column d is the distance on the optical axis from each optical surface to the next optical surface (spacing); column 4 nd and column 5 ν d is the refractive index and Abbe number for d-line (λ = 587.6 nm) Is shown. Also, the radius of curvature 平面 indicates a plane, and the refractive index of air 0000 is omitted. Also, the object plane indicates the observation object O, and the image plane indicates the eye point EP.

Here, the focal length f (fOe, fEe, etc.), radius of curvature r, interplanar spacing d, and other units of length generally used in all the following specification values are generally "mm", but the optical system Is not limited to this, because the same optical performance can be obtained by proportional enlargement or reduction. In addition, the explanation of these symbols and the explanation of the specification table are the same in the following embodiments.

As described above, although not shown in the following embodiments including the present embodiment, between the observation object O and the first lens component G1 or between the fourth lens component G4 and the eye point EP In the case where an optical member such as a cover glass, a prism, a display cover glass or the like is disposed, the surface distance d is an air equivalent length.

(Table 1) First Example [Overall Specifications]
fe = 17.641
H = 6.30
TL = 28.790

[Lens data]
m r d nd d d
Object ∞ D1
1 * 29.01673 6.95 1.77377 47.25
2 *-11.37822 3.03
3 * -6.74812 1.50 1.63552 23.89
4 *-58. 925 77 1.25
5 * -48.01803 5.40 1.53110 55.91
6 *-10.14569 0.50
7 * -1037.93340 2.75 1.53110 55.91
8 *-42.12958 D2
Image plane ∞

In the eyepiece optical system EL1, the first surface, the second surface, the third surface, the fourth surface, the fifth surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. Table 2 below shows data of aspheric surfaces, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 2)
[Aspheric surface data]
First plane K = -1.0414
A4 = -1.29144E-04 A6 = -4.67158E-07 A8 = 1.78024E-08
A10 = -1.65828 E-10 A12 = 6.30320 E-13
Second plane K =-2.2911
A4 = -1.46042E-04 A6 = 1.05047E-06 A8 = -8.71894E-09
A10 = 3.48401 E-11 A12 = 0.00000 E + 00
Third plane K = -0.2684
A4 = 3.35859E-04 A6 = -4.37805E-06 A8 = 2.17895E-08
A10 = -4.94107E-11 A12 = 0.00000E + 00
Fourth plane K = 5.9869
A4 = 9.81668E-05 A6 = -1.20860E-06 A8 = 6.95819E-09
A10 = -1.72138E-11 A12 = 0.00000E + 00
Fifth surface K = 5.9905
A4 = 2.82487E-05 A6 = 1.16190E-06 A8 = -1.23653E-08
A10 = 4.18910E-11 A12 = 0.00000E + 00
Sixth face K = 0.3916
A4 = 1.91131E-04 A6 =-3.21702E-07 A8 =-3.26701E-09
A10 = 2.35655E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.52684E-04 A6 = 1.49017E-06 A8 = -1.20661E-08
A10 = 5.44999E-11 A12 = 0.00000E + 00
Eighth plane K = 3.6084
A4 = -2.40943E-04 A6 = 2.55221E-06 A8 = -1.68422E-08
A10 = 5.77483E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL1, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 3 below shows variable intervals and dioptric pupil positions for each diopter. The diopter represents -1 [1 / m] as "-1 dpt", +2 [1 / m] as "+2 dpt", and -4 [1 / m] as "-4 dpt". The same applies to the following embodiments.

(Table 3)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.41 8.33 6.39
D2 20.60 19.68 21.62
EnP-29.03270-30.46513-27.64176

Table 4 below shows values corresponding to the respective conditional expressions of the eyepiece optical system EL1.

(Table 4)
f4 = 82.602
f12 = 28.790
f23 = -63.706

[Conditional expression corresponding value]
(1) fe / f1 = 1.545
(2) fe / f12 = 0.613
(3) d d 2 = 23.89
(4) fe / f4 = 0.214
(5) (G2R2-G3R1) / (G2R2 + G3R1) =-0.102
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.437
(7) fe / EnP = -0.608
(8) fe / f23 = -0.277
(9) D1 / f1 = 0.649
(10) TL / fe = 1.632
(11) nd1 = 1. 774
(12) nd2 = 1.636

Thus, the eyepiece optical system EL1 satisfies the conditional expressions (1) to (11).

FIG. 2 shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a coma aberration diagram at a standard diopter (−1 dpt) of this eyepiece optical system EL1. The unit of the horizontal axis of the spherical aberration diagram and the astigmatism diagram is “1 / m”, and is indicated by “D” in the diagram. Further, the coma aberration diagram and the magnification chromatic aberration diagram show the components in angle units, and d and g in the diagram show the aberration curve at the d-line and the g-line. Further, the coma aberration diagram shows an aberration curve for each object height. These descriptions also apply to the following embodiments. From these aberration diagrams, it can be seen that this eyepiece optical system EL1 achieves good aberration within the diopter adjustment range.

Second Embodiment
FIG. 3 is a view showing the arrangement of an eyepiece optical system EL2 according to the second embodiment. The eyepiece optical system EL2 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL2, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are formed aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 in the shape of a negative meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed aspheric and having a concave surface facing the observation object It is done. In the third lens component G3, the lens surface on the observation object side and the lens surface on the eye point side are formed in an aspheric shape, and the third lens component G3 is constituted by an aspheric positive lens L31 having a positive meniscus lens shape concave on the object side. ing. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL2 is performed by moving the entire eyepiece optical system EL2 in the optical axis direction.

Table 5 below presents values of specifications of the eyepiece optical system EL2.

(Table 5) Second Example [Overall Specifications]
fe = 18.135
H = 6.30
TL = 28.100

[Lens data]
m r d nd d d
Object ∞ D1
1 * 18.29768 7.45 1.53110 55.91
2 *-8.02783 2.40
3 *-5.08738 2.15 1.6355 23.89
4 * -16.13188 0.50
5 *-46.53675 5.00 1.53110 55.91
6 *-9.94321 0.50
7 * -62.80707 2.30 1.53110 55.91
8 *-36.52997 D2
Image plane ∞

In the eyepiece optical system EL2, the first surface, the second surface, the third surface, the fourth surface, the fifth surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. Table 6 below shows data of aspheric surfaces, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 6)
[Aspheric surface data]
First plane K = 0.4135
A4 = -1.67471E-04 A6 = -2.55937E-06 A8 = 4.54261E-08
A10 = -3.19957E-10 A12 = 1.06400E-12
Second plane K = -2.0545
A4 = -3.02431E-04 A6 = 3.45590E-06 A8 = -3.41508E-08
A10 = 1.41269E-10 A12 = 0.00000E + 00
Third plane K = -0.3061
A4 = 5.48726E-04 A6 = -5.11105E-06 A8 = -4.02571E-10
A10 = 6.06422 E-11 A12 = 0.00000 E + 00
Fourth plane K = -3.9720
A4 = 1.64809E-04 A6 = -6.23672E-07 A8 = -3.44304E-09
A10 = 4.26001E-12 A12 = 0.00000E + 00
Fifth surface K = 5.8883
A4 = -5.24409E-05 A6 = 5.07414E-07 A8 = 3.77890E-09
A10 = -1.41672E-11 A12 = 0.00000E + 00
Sixth face K = 0.4195
A4 = 2.57996E-04 A6 = -1.85757E-06 A8 = 2.18453E-09
A10 = 5.57891E-11 A12 = 0.00000E + 00
Seventh plane K = 4.451
A4 = -8.67424E-05 A6 = 9.74736E-07 A8 = 5.79036E-09
A10 = -6.53413E-11 A12 = 0.00000E + 00
Eighth side K = 5.7525
A4 = -2.08333E-04 A6 = 2.55741E-06 A8 = -6.33475E-09
A10 = -2.34517E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL2, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 7 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 7)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.80 8.77 6.74
D2 20.60 19.63 21.66
EnP-34.92593-37.22500-32.79600

Table 8 below shows values corresponding to the respective conditional expressions of the eyepiece optical system EL2.

(Table 8)
f4 = 162.068
f12 = 33.567
f23 = -93.824

[Conditional expression corresponding value]
(1) fe / f1 = 1.557
(2) fe / f12 = 0.540
(3) d d 2 = 23.89
(4) fe / f4 = 0.112
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.485
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.390
(7) fe / EnP = -0.519
(8) fe / f23 = -0.193
(9) D1 / f1 = 0.670
(10) TL / fe = 1.550
(11) nd1 = 1.531
(12) nd2 = 1.636

Thus, the eyepiece optical system EL2 satisfies the conditional expressions (1) to (10).

FIG. 4 shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram and a coma aberration diagram of the eyepiece optical system EL2 at a standard diopter (-1 dpt). From these aberration diagrams, it can be seen that this eyepiece optical system EL2 achieves good aberration within the diopter adjustment range.

Third Embodiment
FIG. 5 is a view showing the arrangement of an eyepiece optical system EL3 according to the third embodiment. The eyepiece optical system EL3 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL3, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of a biconcave negative lens-shaped aspheric negative lens L12 in which the lens surface on the observation object side is formed in an aspheric shape. The third lens component G3 is composed of an aspheric positive lens L31 having a biconvex positive lens shape in which the lens surface on the eye point side is formed in an aspheric shape. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL3 is performed by moving the entire eyepiece optical system EL3 in the optical axis direction.

Table 9 below presents values of specifications of the eyepiece optical system EL3.

(Table 9) Third Example [Overall Specifications]
fe = 17.654
H = 6.30
TL = 29.118

[Lens data]
m r d nd d d
Object ∞ D1
1 * 37.20780 7.34 1.82098 42.50
2 *-10.78310 2.69
3 *-6.86450 1.58 1.63550 23.89
4 403.03380 0.98
5 365.51190 5.94 1.53110 55.91
6 *-10.45160 0.50
7 *-40.06410 2.69 1.53110 55.91
8 *-25.10660 D2
Image plane ∞

In the eyepiece optical system EL3, the first surface, the second surface, the third surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. Table 10 below shows data of aspheric surfaces, that is, values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 10)
[Aspheric surface data]
First plane K = 3.5010
A4 = -1.08770E-04 A6 = -7.76264E-07 A8 = 1.84546E-08
A10 = -1.13779E-10 A12 = 3.71750E-13
Second plane K = -2.3099
A4 = -1.29893E-04 A6 = 9.59335E-07 A8 = -7.24273E-09
A10 = 3.52620E-11 A12 = 0.00000E + 00
Third plane K = -0.1511
A4 = 4.02440E-04 A6 = -4.00609E-06 A8 = 2.11556E-08
A10 = -1.51294E-10 A12 = 0.00000E + 00
Sixth plane K = 0.5856
A4 = 2.62266E-04 A6 = -6.94589E-07 A8 = -3.75126E-09
A10 = 2.70416E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.21897E-04 A6 = 1.25808E-06 A8 = -5.29696E-09
A10 = 4.01375E-11 A12 = 0.00000E + 00
Eighth plane K = 0.9506
A4 = -2.35090E-04 A6 = 2.42051E-06 A8 = -1.44574E-08
A10 = 7.36171 E-11 A12 = 0.00000 E + 00

In this eyepiece optical system EL3, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 11 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 11)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.41 8.34 6.40
D2 20.60 19.67 21.61
EnP -30.17343 -31.78442 -28.65171

Table 12 below shows values corresponding to the respective conditional expressions of the eyepiece optical system EL3.

(Table 12)
f4 = 119.198
f12 = 34.675
f23 = -70.015

[Conditional expression corresponding value]
(1) fe / f1 = 1.614
(2) fe / f12 = 0.509
(3) d d 2 = 23.89
(4) fe / f4 = 0.148
(5) (G2R2-G3R1) / (G2R2 + G3R1) =-0.049
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.551
(7) fe / EnP = -0.585
(8) fe / f23 = -0.252
(9) D1 / f1 = 0.678
(10) TL / fe = 1.649
(11) nd 1 = 1.821
(12) nd2 = 1.636

Thus, the eyepiece optical system EL3 satisfies the conditional expressions (1) to (11).

FIG. 6 shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a coma aberration diagram at a standard diopter (−1 dpt) of this eyepiece optical system EL3. From these aberration diagrams, it can be seen that this eyepiece optical system EL3 achieves good aberration within the diopter adjustment range.

Fourth Embodiment
FIG. 7 is a view showing the arrangement of an eyepiece optical system EL4 according to the fourth embodiment. The eyepiece optical system EL4 includes, in order from the observation object side, a first lens component G1 having a positive refractive power, a second lens component G2 having a negative refractive power, and a third lens component G3 having a positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL4, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 in the shape of a negative meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed aspheric and having a concave surface facing the observation object It is done. The third lens component G3 is formed of an aspheric positive lens L31 in the shape of a positive meniscus lens whose lens surface on the observation object side and the lens surface on the eye point side are aspheric and whose concave surface is directed to the observation object It is done. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL4 is performed by moving the entire eyepiece optical system EL4 in the optical axis direction.

Table 13 below provides values of specifications of the eyepiece optical system EL4.

(Table 13) Fourth Example [Overall Specifications]
fe = 17.636
H = 6.30
TL = 29.262

[Lens data]
m r d nd d d
Object ∞ D1
1 * 24.08699 7.78 1.77377 47.25
2 *-11.23946 2.66
3 *-6.16897 1.50 1.63550 23.89
4 * -35.90996 1.64
5 * -30.97534 4.55 1.53110 55.91
6 * -9.95862 0.50
7 * -2317.28230 2.89 1.53110 55.91
8 *-41.10583 D2
Image plane ∞

In this eyepiece optical system EL4, the first surface, the second surface, the third surface, the fourth surface, the fifth surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. Table 14 below shows data of aspheric surfaces, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 14)
[Aspheric surface data]
First plane K = 2.7110
A4 = -1.01182E-04 A6 = -1.33523E-06 A8 = 1.97743E-08
A10 = -1.25195E-10 A12 = 4.06080E-13
Second plane K = -2.9040
A4 = -1.58180E-04 A6 = 1.29335E-06 A8 = -1.01444E-08
A10 = 4.38226E-11 A12 = 0.00000E + 00
Third plane K = -0.4456
A4 = 4.04109E-04 A6 = -4.62087E-06 A8 = 2.20818E-08
A10 = -6.21510E-11 A12 = 0.00000E + 00
Fourth plane K = -3.9080
A4 = 1.79698E-04 A6 = -1.03102E-06 A8 =-1.74072E-09
A10 = 1.01196E-11 A12 = 0.00000E + 00
Fifth aspect K = 3.7707
A4 = -3.78236E-06 A6 = 1.16143E-06 A8 = -5.58959E-09
A10 = 1.44702E-12 A12 = 0.00000E + 00
Sixth face K = 0.6581
A4 = 2.55240E-04 A6 = -5.27043E-07 A8 = -3.06199E-10
A10 = 4.00895E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.20441E-04 A6 = 1.18792E-06 A8 = -6.17544E-09
A10 = 2.72498E-11 A12 = 0.00000E + 00
Eighth plane K = -2.5146
A4 = -2.41805E-04 A6 = 2.45866E-06 A8 = -1.44853E-08
A10 = 5.06379E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL4, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 15 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 15)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.75 8.68 6.74
D2 20.60 19.67 21.61
EnP -28.77738 -30.14404 -27.47277

Table 16 below shows values corresponding to the respective conditional expressions of the eyepiece optical system EL4.

(Table 16)
f4 = 78.761
f12 = 26.175
f23 = -44.512

[Conditional expression corresponding value]
(1) fe / f1 = 1.610
(2) fe / f12 = 0.674
(3) d d 2 = 23.89
(4) fe / f4 = 0.224
(5) (G2R2-G3R1) / (G2R2 + G3R1) =-0.074
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.364
(7) fe / EnP = -0.613
(8) fe / f23 = -0.396
(9) D1 / f1 = 0.707
(10) TL / fe = 1.659
(11) nd1 = 1. 774
(12) nd2 = 1.636

Thus, the eyepiece optical system EL4 satisfies the conditional expressions (1) to (11).

FIG. 8 shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a coma aberration diagram of the eyepiece optical system EL4 at a standard diopter (-1 dpt). From these aberration diagrams, it can be seen that this eyepiece optical system EL4 achieves good aberration within the diopter adjustment range.

Fifth Embodiment
FIG. 9 is a view showing the configuration of the eyepiece optical system EL5 according to the fifth example. The eyepiece optical system EL5 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL5, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 in the shape of a negative meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed aspheric and having a concave surface facing the observation object It is done. The third lens component G3 is formed of an aspheric positive lens L31 in the shape of a positive meniscus lens whose lens surface on the observation object side and the lens surface on the eye point side are aspheric and whose concave surface is directed to the observation object It is done. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL5 is performed by moving the entire eyepiece optical system EL5 in the optical axis direction.

Table 17 below provides values of specifications of the eyepiece optical system EL5.

(Table 17) Fifth Example [Overall Specifications]
fe = 18.132
H = 6.30
TL = 27.900

[Lens data]
m r d nd d d
Object ∞ D1
1 * 18.12430 7.15 1.54392 55.90
2 *-8.93740 2.70
3 * -5.25010 2.10 1.63550 23.89
4 * -15.01890 0.55
5 * -24.00760 4.55 1.54392 55.90
6 *-9.36770 0.55
7 * -2317.28230 2.50 1.54392 55.90
8 * -51.99250 D2
Image plane ∞

In this eyepiece optical system EL5, the first surface, the second surface, the third surface, the fourth surface, the fifth surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. Table 18 below shows data of aspheric surfaces, that is, values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 18)
[Aspheric surface data]
First plane K = 1.5721
A4 = -1.48925E-04 A6 = -2.27684E-06 A8 = 2.76091E-08
A10 = -7.95927E-11 A12 = 1.93700E-15
Second plane K =-2.1582
A4 = -2.07700E-04 A6 = 1.44079E-06 A8 =-1.32371E-08
A10 = 7.80799 E-11 A12 = 0.00000 E + 00
Third plane K = -0.3642
A4 = 4.11218E-04 A6 = -4.53688E-06 A8 = 1.52134E-08
A10 = -5.51553E-11 A12 = 0.00000 E + 00
Fourth plane K = -2.1105
A4 = 1.75549E-04 A6 = -6.55035E-07 A8 = -1.17880E-09
A10 = -1.10549E-11 A12 = 0.00000E + 00
Fifth side K =-2.6173
A4 = 3.84318E-05 A6 = 520.426E-07 A8 = -3.63630E-09
A10 = 1.31408 E-11 A12 = 0.00000 E + 00
Sixth face K = 0.5270
A4 = 3.06334E-04 A6 = -1.20258E-06 A8 = -2.58312E-09
A10 = 7.29168E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.44498E-04 A6 = 6.56846E-07 A8 = 4.58887E-09
A10 = -2.74632 E-11 A12 = 0.00000 E + 00
Eighth plane K = 3.4680
A4 = -2.80056E-04 A6 = 2.69450E-06 A8 = -1.10674E-08
A10 = 1.88829E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL5, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 19 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 19)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.80 8.78 6.74
D2 20.70 19.72 21.76
EnP-34.42818 -36.66472 -32.37294

The following Table 20 shows the corresponding values to the conditional expressions of the eyepiece optical system EL5.

(Table 20)
f4 = 97.744
f12 = 31.386
f23 = -77.761

[Conditional expression corresponding value]
(1) fe / f1 = 1.494
(2) fe / f12 = 0.578
(3) d d 2 = 23.89
(4) fe / f4 = 0.186
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.230
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.339
(7) fe / EnP = -0.527
(8) fe / f23 = -0.233
(9) D1 / f1 = 0.643
(10) TL / fe = 1.539
(11) nd 1 = 1.544
(12) nd2 = 1.636

Thus, the eyepiece optical system EL5 satisfies the conditional expressions (1) to (10).

FIG. 10 shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a coma aberration diagram of the eyepiece optical system EL5 at a standard diopter (-1 dpt). From these aberration diagrams, it can be seen that this eyepiece optical system EL5 achieves good aberration within the diopter adjustment range.

Sixth Embodiment
FIG. 11 is a diagram showing the configuration of an eyepiece optical system EL6 according to a sixth example. The eyepiece optical system EL6 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL6, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 in the shape of a negative meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed aspheric and having a concave surface facing the observation object It is done. The third lens component G3 is formed of an aspheric positive lens L31 in the shape of a positive meniscus lens whose lens surface on the observation object side and the lens surface on the eye point side are aspheric and whose concave surface is directed to the observation object It is done. The fourth lens component G4 is composed of an aspheric positive lens L41 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric.

The diopter adjustment in the eyepiece optical system EL6 is performed by moving the entire eyepiece optical system EL6 in the optical axis direction.

Table 21 below provides values of specifications of the eyepiece optical system EL6.

(Table 21) Sixth embodiment [overall specifications]
fe = 18.123
H = 6.30
TL = 28.139

[Lens data]
m r d nd d d
Object ∞ D1
1 * 16.56700 7.54 1.53110 55.91
2 * -8.36450 2.40
3 * -5.15230 2.11 1.63550 23.89
4 * -15.20140 0.72
5 *-23.94520 4.46 1.53110 55.91
6 * -9.83340 0.50
7 * 153.86920 2.57 1.53110 55.91
8 *-57.12010 D2
Image plane ∞

In the eyepiece optical system EL6, the first surface, the second surface, the third surface, the fourth surface, the fifth surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. The following Table 22 shows data of aspheric surfaces, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 22)
[Aspheric surface data]
First plane K = 0.7228
A4 = -1.63997E-04 A6 = -2.61921E-06 A8 = 3.31813E-08
A10 = -1.23005E-10 A12 = 1.44200E-13
Second plane K = -2.0402
A4 = -2.39241E-04 A6 = 1.88690E-06 A8 =-1.74329E-08
A10 = 7.72117 E-11 A12 = 0.00000 E + 00
Third plane K = -0.4513
A4 = 4.08176E-04 A6 = -4.24658E-06 A8 = 1.05383E-08
A10 = -4.81073E-11 A12 = 0.00000E + 00
Fourth plane K = -2.0834
A4 = 1.95661E-04 A6 = -5.64298E-07 A8 = -2.58247E-09
A10 = -1.66041E-11 A12 = 0.00000E + 00
Fifth surface K = -3.9899
A4 = 7.61468E-06 A6 = 4.89100E-07 A8 = 5.08311E-10
A10 = -5.69059E-12 A12 = 0.00000E + 00
Sixth face K = 0.4497
A4 = 2.70507E-04 A6 = -1.61737E-06 A8 = -1.10795E-09
A10 = 7.33076E-11 A12 = 0.00000E + 00
Seventh plane K =-4.0000
A4 = -1.50783E-04 A6 = 6.32142E-07 A8 = 8.23469E-09
A10 = -5.41717E-11 A12 = 0.00000E + 00
Eighth plane K = 4.7540
A4 = -2.61403E-04 A6 = 2.68176E-06 A8 = -9.54981E-09
A10 = 4.35054E-12 A12 = 0.00000E + 00

In this eyepiece optical system EL6, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 23 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 23)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.84 8.82 6.78
D2 20.60 19.62 21.66
EnP-34.03960-36.20254-32.04697

Table 24 below shows the corresponding values to the conditional expressions of the eyepiece optical system EL6.

(Table 24)
f4 = 78.767
f12 = 30.113
f23 = -49.345

[Conditional expression corresponding value]
(1) fe / f1 = 1.550
(2) fe / f12 = 0.602
(3) d d 2 = 23.89
(4) fe / f4 = 0.230
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.223
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.329
(7) fe / EnP = -0.532
(8) fe / f23 = -0.367
(9) D1 / f1 = 0.671
(10) TL / fe = 1.553
(11) nd1 = 1.531
(12) nd2 = 1.636

Thus, the eyepiece optical system EL6 satisfies the conditional expressions (1) to (10).

FIG. 12 shows a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a coma aberration diagram at a standard diopter (−1 dpt) of this eyepiece optical system EL6. From these aberration diagrams, it can be seen that this eyepiece optical system EL6 achieves good aberration within the diopter adjustment range.

Seventh Embodiment
FIG. 13 is a diagram showing the configuration of an eyepiece optical system EL7 according to a seventh example. The eyepiece optical system EL7 includes, in order from the observation object side, a first lens component G1 having a positive refractive power, a second lens component G2 having a negative refractive power, and a third lens component G3 having a positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL7, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 having a negative meniscus lens shape with a concave surface facing the observation object. The third lens component G3 is formed of an aspheric positive lens L31 having a positive meniscus lens shape with a concave surface facing the observation object. The fourth lens component G4 is composed of an aspheric positive lens L41 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric.

The diopter adjustment in the eyepiece optical system EL7 is performed by moving the entire eyepiece optical system EL7 in the optical axis direction.

Table 25 below presents values of specifications of the eyepiece optical system EL7.

(Table 25) Seventh Example [Overall Specifications]
fe = 17.662
H = 6.30
TL = 28.320

[Lens data]
m r d nd d d
Object ∞ D1
1 * 28.07266 7.30 1.74400 44.80
2 *-10. 67758 2. 70
3 * -6.63855 1.55 1.63550 23.89
4 -144.14719 1.00
5 -167.660045 5.95 1.53110 55.91
6 *-11.29042 0.50
7 * 1712.67070 2.70 1.53110 55.91
8 *-31.84183 D2
Image plane ∞

In the eyepiece optical system EL7, the first surface, the second surface, the third surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. The following Table 26 shows aspheric surface data, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 26)
[Aspheric surface data]
First plane K = -2.0140
A4 = -1.26801E-04 A6 = -7.92018E-07 A8 = 1.72033E-08
A10 = −1.32394E-10 A12 = 5.48090E-13
Second plane K = -2.1884
A4 = -1.51405E-04 A6 = 8.63584E-07 A8 = -7.98722E-09
A10 = 2.78537E-11 A12 = 0.00000E + 00
Third plane K = -0.1010
A4 = 3.80395E-04 A6 = -4.01258E-06 A8 = 2.22431E-08
A10 = -1.81820E-10 A12 = 0.00000E + 00
Sixth face K = 0.6429
A4 = 2.44680E-04 A6 = -7.34170E-07 A8 = -4.17875E-09
A10 = 2.11837E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.23377E-04 A6 = 1.23089E-06 A8 = -5.342263E-09
A10 = 3.90858E-11 A12 = 0.00000E + 00
Eighth plane K = -0.0905
A4 = -2.34359E-04 A6 = 2.48218E-06 A8 = -1.41661E-08
A10 = 7.75465 E-11 A12 = 0.00000 E + 00

In this eyepiece optical system EL7, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 27 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 27)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 6.62 7.55 5.61
D2 20.10 19.17 21.11
EnP-30.15672-31.88364-28.53315

Table 28 below shows values corresponding to the respective conditional expressions of the eyepiece optical system EL7.

(Table 28)
f4 = 58.892
f12 = 34.529
f23 = -45.926

[Conditional expression corresponding value]
(1) fe / f1 = 1.562
(2) fe / f12 = 0.512
(3) d d 2 = 23.89
(4) fe / f4 = 0.300
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.075
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.449
(7) fe / EnP = -0.586
(8) fe / f23 = -0.385
(9) D1 / f1 = 0.586
(10) TL / fe = 1.603
(11) nd1 = 1.744
(12) nd2 = 1.636

Thus, the eyepiece optical system EL7 satisfies the conditional expressions (1) to (11).

FIG. 14 shows a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram and a coma aberration diagram of the eyepiece optical system EL7 at a standard diopter (−1 dpt). From these aberration diagrams, it can be seen that this eyepiece optical system EL7 achieves good aberration within the diopter adjustment range.

Eighth Embodiment
FIG. 15 is a view showing the configuration of an eyepiece optical system EL8 according to an eighth example. The eyepiece optical system EL8 includes, in order from the observation object side, a first lens component G1 having a positive refractive power, a second lens component G2 having a negative refractive power, and a third lens component G3 having a positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL8, the first lens component G1 has an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side is aspheric, and an aspheric lens surface on the eye point side And a cemented lens obtained by cementing a positive meniscus lens-shaped aspheric positive lens L12 having a concave surface facing the observation object. The second lens component G2 is formed of an aspheric negative lens L12 having a negative meniscus lens shape with a concave surface facing the observation object. The third lens component G3 is formed of an aspheric positive lens L31 having a positive meniscus lens shape with a concave surface facing the observation object. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL8 is performed by moving the entire eyepiece optical system EL8 in the optical axis direction.

Table 29 below provides values of specifications of the eyepiece optical system EL8.

(Table 29) Eighth Example [Overall Specifications]
fe = 17.671
H = 6.30
TL = 28.340

[Lens data]
m r d nd d d
Object ∞ D1
1 * 36.28535 1.50 1.75520 27.57
2 -256.85195 5.55 1.74400 44.80
3 *-9.58387 2.70
4 *-6.33627 1.60 1.63550 23.89
5 -309.22499 1.00
6-340.41004 5.95 1.53110 55.91
7 *-10.20313 0.50
8 * -118.11140 2.70 1.53110 55.91
9 * -33.13998 D2
Image plane ∞

In the eyepiece optical system EL8, the first surface, the third surface, the fourth surface, the seventh surface, the eighth surface and the ninth surface are formed in an aspheric shape. The following Table 30 shows data of aspheric surfaces, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 30)
[Aspheric surface data]
First plane K =-2.0658
A4 = -1.42501E-04 A6 = -8.76658E-07 A8 = 1.88394E-08
A10 = -1.09268E-10 A12 = 3.68460E-13
Third plane K = -1.7532
A4 = -1.52859E-04 A6 = 8.23715E-07 A8 = -8.45101E-09
A10 = 3.67563E-11 A12 = 0.00000E + 00
Fourth plane K =-0.2498
A4 = 3.64026E-04 A6 = -4.01765E-06 A8 = 2.07275E-08
A10 = -1.61058E-10 A12 = 0.00000E + 00
Seventh plane K = 0.5740
A4 = 2.54149E-04 A6 = -6.232718E-07 A8 = -3.76424E-09
A10 = 2.73 994 E-11 A12 = 0.00000 E + 00
Eighth plane K = 1.0000
A4 = -1.19587E-04 A6 = 1.18521E-06 A8 = -5.01478E-09
A10 = 4.10280E-11 A12 = 0.00000E + 00
The ninth side K = 1.4393
A4 = -2.39375E-04 A6 = 2.51700E-06 A8 = -1.48286E-08
A10 = 7.54336 E-11 A12 = 0.00000 E + 00

In this eyepiece optical system EL8, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 31 below shows variable intervals for each diopter and entrance pupil positions.

(Table 31)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 6.84 7.77 5.83
D2 20.10 19.17 21.11
EnP-31.23485-33.09550-29.49620

Table 32 below shows the corresponding values to the conditional expressions of the eyepiece optical system EL8.

(Table 32)
f4 = 85.790
f12 = 37.94
f23 = -57.363

[Conditional expression corresponding value]
(1) fe / f1 = 1.625
(2) fe / f12 = 0.465
(3) d d 2 = 23.89
(4) fe / f4 = 0.206
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.048
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.582
(7) fe / EnP = -0.566
(8) fe / f23 = -0.308
(9) D1 / f1 = 0.629
(10) TL / fe = 1.604
(11) nd1 = 1.755
(12) nd2 = 1.636

Thus, the eyepiece optical system EL8 satisfies the conditional expressions (1) to (11).

The spherical aberration view, the astigmatism view, the distortion view and the coma view of the eyepiece optical system EL8 at a standard diopter (-1 dpt) are shown in FIG. From these aberration diagrams, it can be seen that this eyepiece optical system EL8 achieves good aberration within the diopter adjustment range.

[Ninth embodiment]
FIG. 17 is a view showing the configuration of an eyepiece optical system EL9 according to a ninth example. The eyepiece optical system EL9 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL9, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. The second lens component G2 is formed of an aspheric negative lens L12 having a negative meniscus lens shape with a concave surface facing the observation object. The third lens component G3 is formed of an aspheric positive lens L31 having a positive meniscus lens shape with a concave surface facing the observation object. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL9 is performed by moving the entire eyepiece optical system EL9 in the optical axis direction.

Table 33 below provides values of specifications of the eyepiece optical system EL9.

(Table 33) Ninth Example [Overall Specifications]
fe = 17.664
H = 6.30
TL = 28.440

[Lens data]
m r d nd d d
Object ∞ D1
1 * 30.06223 7.30 1.74300 49.25
2 *-10.46380 2.70
3 * -6.62848 1.55 1.65093 21.51
4-43.12860 1.00
5 -44.49530 5.95 1.53110 55.91
6 *-10.78420 0.50
7 * -1133.34000 2.70 1.53110 55.91
8 * -34.07780 D2
Image plane ∞

In the eyepiece optical system EL9, the first surface, the second surface, the third surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. Table 34 below shows data of aspheric surfaces, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 34)
[Aspheric surface data]
First plane K = -1.3191
A4 = -1.08297E-04 A6 = -5.23642E-07 A8 = 1.65142E-08
A10 = -1.39777E-10 A12 = 5.22770E-13
Second plane K = -2.1775
A4 = -1.37725E-04 A6 = 9.31664E-07 A8 = -7.77285E-09
A10 = 2.31975E-11 A12 = 0.00000E + 00
Third plane K = -0.0873
A4 = 3.71838E-04 A6 = -4.12160E-06 A8 = 2.25930E-08
A10 = -1.98410E-10 A12 = 0.00000E + 00
Sixth face K = 0.6318
A4 = 2.37664E-04 A6 = -7.12383E-07 A8 = -4.02440E-09
A10 = 2.46401E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.19476E-04 A6 = 1.21154E-06 A8 = -5.10047E-09
A10 = 4.12044E-11 A12 = 0.00000E + 00
Eighth plane K =-0.6189
A4 = -2.332309E-04 A6 = 2.50741E-06 A8 = -1.40702E-08
A10 = 7.88020E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL9, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 35 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 35)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 6.74 7.67 5.73
D2 20.00 19.07 20.01
EnP-31.17085-32. 51888-29.03853

The following Table 36 shows the corresponding values to the conditional expressions of the eyepiece optical system EL9.

(Table 36)
f4 = 66.097
f12 = 29.977
f23 = -51.032

[Conditional expression corresponding value]
(1) fe / f1 = 1.561
(2) fe / f12 = 0.589
(3) d d 2 = 21.51
(4) fe / f4 = 0.267
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.016
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.484
(7) fe / EnP = -0.567
(8) fe / f23 = -0.346
(9) D1 / f1 = 0.596
(10) TL / fe = 1.610
(11) nd1 = 1.743
(12) nd2 = 1.651

Thus, the eyepiece optical system EL9 satisfies the conditional expressions (1) to (12).

The spherical aberration view, the astigmatism view, the distortion view, and the coma view of the eyepiece optical system EL9 at a standard diopter (-1 dpt) are shown in FIG. From these aberration diagrams, it can be seen that this eyepiece optical system EL9 achieves good aberration within the diopter adjustment range.

Tenth Embodiment
FIG. 19 is a diagram showing the configuration of an eyepiece optical system EL10 according to a tenth example. The eyepiece optical system EL10 includes, in order from the observation object side, a first lens component G1 having a positive refractive power, a second lens component G2 having a negative refractive power, and a third lens component G3 having a positive refractive power. And a fourth lens component G4 having a positive refractive power.

In this eyepiece optical system EL10, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which the lens surface on the observation object side and the lens surface on the eye point side are aspheric. There is. Further, the second lens component G2 is configured of an aspheric negative lens L21 having a negative meniscus lens shape whose concave surface is directed to the observation object side, with the lens surface on the observation object side and the lens surface on the eye point side being aspheric. It is done. The third lens component G3 is formed of an aspheric positive lens L31 in the shape of a positive meniscus lens whose lens surface on the observation object side and the lens surface on the eye point side are aspheric and whose concave surface is directed to the observation object It is done. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL10 is performed by moving the entire eyepiece optical system EL10 in the optical axis direction.

Table 37 below provides values of specifications of the eyepiece optical system EL10.

(Table 37) Tenth Example [Overall Specifications]
fe = 17.655
H = 6.30
TL = 28.870

[Lens data]
m r d nd d d
Object ∞ D1
1 * 27.64520 7.35 1.74300 49.25
2 * -10.59980 2.70
3 * -6.62160 1.50 1.66133 20.35
4 *-30.14490 1.00
5 * -33.42740 5.95 1.53110 55.91
6 * -11.06910 0.50
7 *-447.12000 2.70 1.53110 55.91
8 * -33.61500 D2
Image plane ∞

In the eyepiece optical system EL10, the first surface, the second surface, the third surface, the fourth surface, the fifth surface, the sixth surface, the seventh surface, and the eighth surface are formed in an aspheric shape. The following Table 38 shows aspheric surface data, that is, values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 38)
[Aspheric surface data]
First plane K = 1.8706
A4 = -1.58806E-04 A6 = -6.47977E-07 A8 = 2.00513E-08
A10 = -1.19924E-10 A12 = 3.39780E-13
Second plane K = -2.5122
A4 = -1.82235E-04 A6 = 1.26664E-06 A8 = -9.55146E-09
A10 = 4.41287E-11 A12 = 0.00000E + 00
Third plane K = -0.1010
A4 = 3.59553E-04 A6 = -3.81376E-06 A8 = 2.31702E-08
A10 = -1.65901E-10 A12 = 0.00000E + 00
Fourth plane K = 1.2085
A4 = 9.08220E-06 A6 = 4.92684E-09 A8 = 2.99069E-11
A10 = 0.00000E + 00 A12 = 0.00000E + 00
Fifth plane K = -0.6362
A4 = 2.08532E-05 A6 = 3.39041E-08 A8 = -4.09295E-10
A10 = 0.00000E + 00 A12 = 0.00000E + 00
Sixth face K = 0.5759
A4 = 2.44689E-04 A6 = -6.87340E-07 A8 = -4.20734E-09
A10 = 2.20759E-11 A12 = 0.00000E + 00
Seventh plane K = 1.0000
A4 = -1.28197E-04 A6 = 1.23524E-06 A8 = -5.32987E-09
A10 = 3.98596E-11 A12 = 0.00000E + 00
Eighth plane K = 0.3803
A4 = -2.29306E-04 A6 = 2.47452E-06 A8 = -1.42769E-08
A10 = 7.86334E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL10, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 39 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 39)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.17 8.10 6.16
D2 20.10 19.17 21.11
EnP -30.13523 -31.77608 -28.58721

The following Table 40 shows the corresponding values to the conditional expressions of the eyepiece optical system EL10.

(Table 40)
f4 = 68.284
f12 = 26.280
f23 = -47.435

[Conditional expression corresponding value]
(1) fe / f1 = 1.572
(2) fe / f12 = 0.672
(3) d d 2 = 20.35
(4) fe / f4 = 0.259
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.047
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.446
(7) fe / EnP = -0.586
(8) fe / f23 = -0.372
(9) D1 / f1 = 0.638
(10) TL / fe = 1.635
(11) nd1 = 1.743
(12) nd2 = 1.661

Thus, the eyepiece optical system EL10 satisfies the conditional expressions (1) to (12).

The spherical aberration view, the astigmatism view, the distortion view and the coma view of the eyepiece optical system EL10 at a standard diopter (-1 dpt) are shown in FIG. From these aberration diagrams, it can be seen that in this eyepiece optical system EL10, good aberration is achieved within the diopter adjustment range.

Eleventh Embodiment
FIG. 21 is a diagram showing the configuration of an eyepiece optical system EL11 according to an eleventh example. The eyepiece optical system EL11 includes, in order from the observation object side, a first lens component G1 having positive refractive power, a second lens component G2 having negative refractive power, and a third lens component G3 having positive refractive power. And a fourth lens component G4 having a positive refractive power.

In the eyepiece optical system EL11, the first lens component G1 is composed of an aspheric positive lens L11 having a biconvex positive lens shape in which a lens surface on the observation object side is formed in an aspheric shape. The second lens component G2 is a biconcave negative lens-shaped aspheric negative lens L21 in which the lens surface on the observation object side is aspheric, and a lens surface in the eyepoint side is aspheric. It is comprised with the cemented lens which joined the aspheric positive lens L22 of convex positive lens shape. The third lens component G3 is formed of an aspheric positive lens L31 having a positive meniscus lens shape with a concave surface facing the observation object. The fourth lens component G4 is formed of an aspheric positive lens L41 in the shape of a positive meniscus lens having a lens surface on the observation object side and a lens surface on the eye point side formed in an aspheric shape and having a concave surface facing the observation object It is done.

The diopter adjustment in the eyepiece optical system EL11 is performed by moving the entire eyepiece optical system EL11 in the optical axis direction.

Table 41 below provides values of specifications of the eyepiece optical system EL11.

(Table 41) Eleventh embodiment [overall specifications]
fe = 17.623
H = 6.30
TL = 30.240

[Lens data]
m r d nd d d
Object ∞ D1
1 * 28.78836 7.35 1.82098 42.50
2-11.25246 2.70
3 *-7.11620 1.50 1.63552 23.89
4 564.01019 1.48 1.53110 55.91
5 * -165.33547 1.00
6-397.01843 5.95 1.53110 55.91
7 * -11.70908 0.5
8 * -87.51711 2.70 1.53110 55.91
9 * -33.70935 D2
Image plane ∞

In the eyepiece optical system EL11, the first surface, the third surface, the fifth surface, the seventh surface, the eighth surface and the ninth surface are formed in an aspheric shape. The following Table 42 shows aspheric surface data, that is, the values of the conical constant K and the respective aspheric constants A4 to A12.

(Table 42)
[Aspheric surface data]
First plane K = 4.9064
A4 = -1.05219E-04 A6 = -6.2 1990E-07 A8 = 1.81446E-08
A10 = -1. 14918E-10 A12 = 3.47790E-13
Third plane K = -2.7141
A4 = -1.22865E-04 A6 = 1.06684E-06 A8 = -6.77704E-09
A10 = 4.48572E-11 A12 = 0.00000E + 00
Fifth plane K = -0.1268
A4 = 3.96618E-04 A6 = -3.89261E-06 A8 = 2.32375E-08
A10 = -1.45358E-10 A12 = 0.00000E + 00
Seventh plane K = 0.5892
A4 = 2.52841E-04 A6 = -6.99186E-07 A8 = -4.09567E-09
A10 = 2.38163E-11 A12 = 0.00000E + 00
Eighth plane K = 1.0000
A4 = -1.15871E-04 A6 = 1.20055E-06 A8 = -5.20908E-09
A10 = 4.32497E-11 A12 = 0.00000E + 00
The ninth side K = 2.7036
A4 = -2.43083E-04 A6 = 2.51325E-06 A8 = -1.39088E-08
A10 = 7.50477E-11 A12 = 0.00000E + 00

In this eyepiece optical system EL11, the on-axis air gap D1 between the observation object and the first lens component G1 and the on-axis air gap D2 between the fourth lens component G4 and the eyepoint EP change during diopter adjustment. In addition, the entrance pupil position EnP also changes with the change of these intervals. Table 43 below shows variable intervals and dioptric pupil positions for each diopter.

(Table 43)
[Variable interval data]
Diopter -1 dpt +2 dpt -4 dpt
D1 7.06 7.98 6.04
D2 20.10 19.18 21.12
EnP-27.40929-28.67303-26.17269

The following Table 44 shows the corresponding values to the conditional expressions of the eyepiece optical system EL11.

(Table 44)
f4 = 101.468
f12 = 26.176
f23 = -66.090

[Conditional expression corresponding value]
(1) fe / f1 = 1.640
(2) fe / f12 = 0.673
(3) d d 2 = 23.89
(4) fe / f4 = 0.174
(5) (G2R2-G3R1) / (G2R2 + G3R1) = 0.412
(6) (G1R2 + G1R1) / (G1R2-G1R1) =-0.438
(7) fe / EnP = -0.643
(8) fe / f23 = -0.267
(9) D1 / f1 = 0.657
(10) TL / fe = 1.716
(11) nd 1 = 1.821
(12) nd2 = 1.636

Thus, the eyepiece optical system EL10 satisfies the conditional expressions (1) to (11).

The spherical aberration view, the astigmatism view, the distortion view, and the coma view of the eyepiece optical system EL11 at a standard diopter (-1 dpt) are shown in FIG. From these aberration diagrams, it can be seen that in this eyepiece optical system EL11, good aberration is achieved within the diopter adjustment range.

In addition, the content described below can be suitably employ | adopted in the range which does not impair optical performance.

In this embodiment, although the thing of the composition of four lens components was shown as a numerical example of eyepiece optical system EL, it is applicable also to other lens composition, such as five lens components, for example. Further, the lens component may be added to the most object side or the lens component may be added to the most eye point side.

In addition, one or more lens components are moved so as to have a displacement component in the direction orthogonal to the optical axis, or rotationally moved (sway) in the in-plane direction including the optical axis to correct image blurring caused by camera shake. It is good also as an anti-vibration lens group. In particular, it is preferable to use the third lens component G3 as a vibration reduction lens group.

Further, the lens surface of the lens (lens component, lens element) constituting the eyepiece optical system EL of the present embodiment may be a spherical surface, a flat surface, or an aspheric surface. When the lens surface is spherical or flat, it is preferable because lens processing and assembly adjustment can be facilitated, and deterioration of optical performance due to lens processing and assembly adjustment errors can be prevented. In addition, even when the image plane shifts, it is preferable because there is little deterioration in the imaging performance. When the lens surface is aspheric, it is either aspheric by grinding, a glass mold aspheric obtained by molding glass into an aspheric shape, or a composite aspheric made by forming a resin provided on the surface of glass into an aspheric shape. May be. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

In addition, in the lens surface of the lens (lens component, lens element) constituting the eyepiece optical system EL of the present embodiment, flare and ghost are reduced, and high contrast optical performance is achieved in a wide wavelength range. An antireflective film having high transmittance may be provided.

In the eyepiece optical system EL of the present embodiment, the first lens component G1, the second lens component G2, the third lens component G3, and the fourth lens component G4 are integrated, or the entire eyepiece optical system EL is integrally moved. The lens component on the eye point side is fixed most, and the entire lens component on the observation object side with respect to the lens component is integrally moved, or the first lens component G1 and the first lens component G1 are The configuration may be such that at least a part of lens components of the two-lens component G2, the third lens component G3, and the fourth lens component G4 are moved. In particular, it is preferable to move the first lens component G1 and to fix the position of the other lens components with respect to the image plane at the time of diopter adjustment. The diopter adjustment lens group is preferably composed of a single lens.

EL (EL1 to EL11) Eyepiece optical system G1 first lens component G2 second lens component G3 third lens component G4 fourth lens component 1 camera (optical apparatus)

Claims

From the observation object side,
A first lens component having a positive refractive power;
A second lens component having a negative refractive power,
A third lens component having a positive refractive power;
And a fourth lens component having a positive refractive power,
Eyepiece optical system that satisfies the condition of the following equation.
1.38 <fe / f1 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f1: focal length of the first lens component "lens component" means a single lens or a cemented lens.
From the observation object side,
A first lens component having a positive refractive power;
A second lens component having a negative refractive power,
A third lens component having a positive refractive power;
And a fourth lens component having a positive refractive power,
Eyepiece optical system that satisfies the condition of the following equation.
0.48 <fe / f12 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f12: combined focal length of the first lens component and the second lens component "lens component" means a single lens or a cemented lens.
The eyepiece optical system according to claim 1, which satisfies the condition of the following formula.
0.48 <fe / f12 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f12: combined focal length of the first lens component and the second lens component
The eyepiece optical system according to any one of claims 1 to 3, wherein the lens surface on the eye point side of the lens closest to the eye point is convex on the eye point side.
The eyepiece optical system according to any one of claims 1 to 4, wherein at least one of the lens elements constituting the second lens component satisfies the following condition.
15.0 <d d2 <35.0
However,
d d2: Abbe number to the d-line of the medium of the lens element constituting the second lens component
The eyepiece optical system according to any one of claims 1 to 5, which satisfies the following condition.
0.01 <fe / f4 <0.33
However,
fe: Focal length of the whole system of the eyepiece optical system f4: Focal length of the fourth lens component
The eyepiece optical system according to any one of claims 1 to 6, which satisfies the condition of the following formula.
-0.30 <(G2R2-G3R1) / (G2R2 + G3R1) <0.50
However,
G2R2: Radius of curvature of lens surface closest to the eye point of the second lens component G3R1: Radius of curvature of lens surface closest to the observation object of the third lens component
The eyepiece optical system according to any one of claims 1 to 7, which satisfies the condition of the following formula.
-0.75 <(G1R2 + G1R1) / (G1R2-G1R1) <0.00
However,
G1R1: The radius of curvature of the lens surface closest to the observation object on the first lens component G1R2: The radius of curvature of the lens surface closest to the eyepoint on the first lens component
The eyepiece optical system according to any one of claims 1 to 8, which satisfies the following condition.
-1.00 <fe / EnP <-0.48
However,
fe: Focal length of the whole system of the eyepiece optical system EnP: Entrance pupil position of the eyepiece optical system at a reference diopter (the code is positive on the eye point side with respect to the observation object surface)
The eyepiece optical system according to any one of claims 1 to 9, which satisfies the following condition.
-0.40 <fe / f23 <-0.15
However,
fe: focal length of the whole system of the eyepiece optical system f23: combined focal length of the second lens component and the third lens component
The eyepiece optical system according to any one of claims 1 to 10, which satisfies the condition of the following formula.
0.58 <D1 / f1 <0.90
However,
D1: Air conversion distance from the observation object to the lens surface closest to the observation object in the reference diopter f1: Focal distance of the first lens component
The eyepiece optical system according to any one of claims 1 to 11, which satisfies the following condition.
1.50 <TL / fe <1.80
However,
TL: total length of the eyepiece optical system fe: focal length of the entire eyepiece optical system
The eyepiece optical system according to any one of claims 1 to 12, which satisfies the following condition.
1.550 <nd 1 <1.800
However,
nd1: the refractive index to the d-line of the medium of the lens element constituting the first lens component
The eyepiece optical system according to any one of claims 1 to 13, which satisfies the following condition.
1.640 <nd 2 <1.800
However,
nd 2: refractive index to the d-line of the medium of the lens element constituting the second lens component
The eyepiece optical system according to any one of claims 1 to 14, wherein diopter adjustment is performed by moving the entire eyepiece optical system in the optical axis direction.
An optical apparatus comprising the eyepiece optical system according to any one of claims 1 to 15.
In order from the observation object side, a first lens component having a positive refractive power, a second lens component having a negative refractive power, a third lens component having a positive refractive power, and a fourth lens component having a positive refractive power A method of manufacturing an eyepiece optical system having a lens component, comprising:
The manufacturing method of the eyepiece optical system arrange | positioned so that the conditions of following Formula may be satisfied.
1.38 <fe / f1 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f1: focal length of the first lens component "lens component" means a single lens or a cemented lens.
In order from the observation object side, a first lens component having a positive refractive power, a second lens component having a negative refractive power, a third lens component having a positive refractive power, and a fourth lens component having a positive refractive power A method of manufacturing an eyepiece optical system having a lens component, comprising:
The manufacturing method of the eyepiece optical system arrange | positioned so that the conditions of following Formula may be satisfied.
0.48 <fe / f12 <3.00
However,
fe: focal length of the whole system of the eyepiece optical system f12: combined focal length of the first lens component and the second lens component "lens component" means a single lens or a cemented lens.