JP2016051063A - Ocular lens and observation device including the same, and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ocular lens having a long eye relief, a wide viewing angle, and high optical performance, an observation device including the same, and an imaging apparatus.SOLUTION: An ocular lens includes, in order from an object side to an image side, a first lens having positive refractive power, a second lens having negative refractive power, a third lens having positive refractive power, and a fourth lens having negative refractive power. When R21 represents a curvature radius of a lens surface on an object side of the second lens and R32 represents a curvature radius of a lens surface on an observation side of the third lens, the ocular lens satisfies -12.00<(R21+R32)/(R21-R32)<-3.00.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an eyepiece and an observation apparatus and an imaging apparatus having the same, and is suitable for observing an image displayed on an image display element in an electronic viewfinder used in, for example, a video camera, a still camera, and a broadcast camera. Is.

  2. Description of the Related Art Conventionally, an electronic viewfinder used in an optical apparatus such as a video camera or a broadcast camera is provided with an eyepiece lens for magnifying and observing an image displayed on a liquid crystal screen provided in the camera.

  2. Description of the Related Art In recent years, electronic viewfinders that have a wide field of view and can display a large image have been demanded with the enhancement of functions of imaging devices. As a method for realizing such a demand, there are a method of enlarging an image display surface such as a liquid crystal screen and a method of increasing the observation magnification of the eyepiece.

  Here, when the image display surface is enlarged, the size of the finder is increased. Therefore, in order to reduce the size of the finder as a whole, it is preferable to increase the observation magnification of the eyepiece. In order to increase the observation magnification of the eyepiece, it is necessary to increase the positive refractive power of the eyepiece. Here, if an eyepiece lens is configured only with a lens having a positive refractive power (positive lens), many axial chromatic aberrations, lateral chromatic aberrations and the like are generated, and it is difficult to correct them. Therefore, in order to obtain a high-definition observation image while increasing the observation magnification of the eyepiece, it is preferable to configure the eyepiece using a lens having a negative refractive power (negative lens) in addition to the positive lens. Thereby, an observation image in which the longitudinal chromatic aberration and the lateral chromatic aberration are corrected well can be obtained.

  There is also a need for a finder with a long eye relief that can be used even when the user is wearing glasses.

  Patent Document 1 discloses an eyepiece lens including a positive lens, a negative lens, a positive lens, a negative lens, and a positive lens in order from the object side to the observation side (eye point side). By using a plurality of positive lenses, an eyepiece with a short focal length and a long eye relief is realized.

JP 2001-272610 A

  As described above, in order to realize an eyepiece having a long eye relief and a wide viewing angle, an eyepiece having a positive lens, a negative lens, a positive lens, and a negative lens in order from the object side to the observation side (eye point side). It has been known.

  In the eyepiece of Patent Document 1, since the curvature of the lens surface of the negative lens arranged second from the object side and the positive lens arranged third from the object side is large, coma and astigmatism are sufficiently reduced. There is a possibility that it cannot be corrected.

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

The eyepiece of the present invention includes a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens having a negative refractive power in order from the object side to the observation side. When the radius of curvature of the lens surface on the object side of the second lens is R21, and the radius of curvature of the lens surface on the observation side of the third lens is R32,
−12.00 <(R21 + R32) / (R21−R32) <− 3.00
The following conditional expression is satisfied.

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

1 is a cross-sectional view of an eyepiece lens according to Example 1 of the present invention. Each aberration diagram of the eyepiece of Example 1 of the present invention Sectional view of eyepiece of Example 2 of the present invention Each aberration diagram of the eyepiece of Example 2 of the present invention Lens cross-sectional view of the eyepiece of Example 3 of the present invention Each aberration diagram of the eyepiece of Example 3 of the present invention Lens cross section of the eyepiece of Example 4 of the present invention Each aberration diagram of the eyepiece lens of Example 4 of the present invention Lens cross section of the eyepiece of Example 5 of the present invention Each aberration diagram of the eyepiece lens of Example 5 of the present invention Lens cross section of the eyepiece of Example 6 of the present invention Each aberration diagram of the eyepiece lens of Example 6 of the present invention Lens cross section of the eyepiece of Example 7 of the present invention Each aberration diagram of the eyepiece lens of Example 7 of the present invention Lens cross section of the eyepiece of Example 8 of the present invention Each aberration diagram of the eyepiece lens of Example 8 of the present invention Schematic diagram of main parts of an imaging apparatus of the present invention Relationship between refractive power arrangement of optical system and optical path

  Hereinafter, an eyepiece of the present invention, an observation apparatus having the same, and an imaging apparatus will be described in detail with reference to the accompanying drawings. The eyepiece of the present invention has a first lens having a positive refractive power, a second lens having a negative refractive power, and a first lens having a positive refractive power in order from the object side (image display surface side) to the observation side (eye point side). 3 lenses and a fourth lens having a negative refractive power.

  Specifically, the eyepieces of Examples 1 to 4 are, in order from the object side to the observation side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, The lens is composed of a fourth lens having a negative refractive power and a fifth lens having a positive refractive power.

  The eyepieces of Examples 5 to 8 are, in order from the object side to the observation side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a negative lens having a negative refractive power. The lens includes a fourth lens, a fifth lens having a positive refractive power, and a sixth lens having a positive refractive power.

  FIG. 1 is a lens cross-sectional view when the diopter of the eyepiece of Example 1 is −2.0 diopter (reference state), 2.5 diopter, and −6.0 diopter. FIG. 2 is an aberration diagram of the eyepiece of Example 1 in the reference state. FIG. 3 is a lens cross-sectional view when the diopter of the eyepiece of Example 2 is −2.0 diopter (reference state), 0.7 diopter, and −3.3 diopter. FIG. 4 is an aberration diagram of the eyepiece of Example 2 in the reference state.

  FIG. 5 is a lens cross-sectional view when the diopter of the eyepiece of Example 3 is −2.0 diopter (reference state), 2.0 diopter, and −4.0 diopter. FIG. 6 is an aberration diagram of the eyepiece lens of Example 3 in the reference state. FIG. 7 is a lens cross-sectional view when the diopter of the eyepiece of Example 4 is −2.0 diopter (reference state), 2.0 diopter, and −4.0 diopter. FIG. 8 is an aberration diagram of the eyepiece of Example 4 in the reference state.

  FIG. 9 is a lens cross-sectional view when the diopter of the eyepiece lens of Example 5 is −2.0 diopter (reference state), 2.0 diopter, and −4.0 diopter. FIG. 10 is an aberration diagram of the eyepiece lens of Example 5 in the reference state. FIG. 11 is a lens cross-sectional view when the diopter of the eyepiece of Example 6 is −2.0 diopter (reference state), 2.0 diopter, and −4.0 diopter. FIG. 12 is an aberration diagram of the eyepiece lens of Example 6 in the reference state.

  FIG. 13 is a lens cross-sectional view when the diopter of the eyepiece of Example 7 is −2.0 diopter (reference state), 2.0 diopter, and −4.0 diopter. FIG. 14 is an aberration diagram of the eyepiece lens of Example 7 in the reference state. FIG. 15 is a lens cross-sectional view when the diopter of the eyepiece of Example 8 is −2.0 diopter (reference state), 2.4 diopter, and −5.8 diopter. FIG. 16 is an aberration diagram of the eyepiece lens of Example 8 in the reference state.

  FIG. 17 is a schematic diagram of a main part of an imaging apparatus including the eyepiece of the present invention. FIG. 18 is a diagram showing that the optical path changes depending on the refractive power arrangement of the optical system.

  The eyepiece of each embodiment is used for an electronic viewfinder of an imaging apparatus such as a digital camera or a video camera. In the lens cross-sectional view, the left side is the image display surface side (object side), and the right side is the observation side. In the lens cross-sectional view, L is an eyepiece. I is an image display surface of an image display element such as a liquid crystal element or an organic EL element. EP is an eye point for the user to observe an image displayed on the display surface.

  A plate for protecting the image display surface and the lens may be provided between the image display surface I and the lens surface on the image display surface side of the lens disposed closest to the image display surface. Further, a plate or the like for protecting the lens may be provided between the eyepiece lens L and the eye point EP. Here, the eye point EP may be moved in the optical axis direction as long as the off-axis light beam emitted from the image display surface I can pass through the pupil of the observer.

  Each aberration diagram shows aberrations that occur in the eyepieces of the examples when the finder diopter is in the reference state.

  In the spherical aberration diagram, spherical aberrations with respect to d-line (wavelength 587.6 nm) and g-line (wavelength 435.8 nm) are shown. In the astigmatism diagram, S is a sagittal image plane, and M is a meridional image plane. Distortion is shown for the d-line. The chromatic aberration diagram shows the chromatic aberration at the g-line.

  Next, the relationship between the refractive power arrangement of the eyepiece and the path of the light beam that passes through the eyepiece will be described with reference to FIG.

  First, referring to FIG. 18, the path of the light beam in the optical system in which the positive lens is disposed closest to the image display surface of the eyepiece and the path of the light beam in the optical system in which the negative lens is disposed closest to the image display surface of the eyepiece. Compare FIG. 18A shows a path of light rays in an optical system in which a positive lens is arranged closest to the image display surface of the eyepiece. FIG. 18B shows a light ray path in an optical system in which a negative lens is arranged closest to the image display surface of the eyepiece.

  As shown in FIGS. 18A and 18B, the effective diameter of a lens (hereinafter referred to as an image display surface side lens) arranged closest to the image display surface among the eyepieces is Depends on size. Further, the effective diameter of a lens (hereinafter referred to as an observation side lens) arranged most on the observation side among the eyepiece lenses is determined by the eye point EP, the viewing angle ω, and the eye relief length. Thus, the effective diameters of the image display surface side lens and the observation side lens are determined according to the specifications of the viewfinder.

  Further, when the eyepiece is used in an electronic viewfinder, it is preferable that the angle of light (image emission angle) emitted from the image display surface and incident on the image display surface side lens is as small as possible. This is because the light emitted obliquely from the image display surface such as a liquid crystal tends to decrease in luminance.

  On the other hand, the effective diameter of a lens (hereinafter referred to as an intermediate lens) disposed between the image display surface side lens and the observation side lens changes according to the refractive power arrangement of the optical system. As shown in FIG. 18A, if the image display surface side lens and the observation side lens are positive lenses, the light beam emitted from the image display surface becomes convergent light in the image display surface side lens. This is smaller than the effective diameter of the image display surface side lens and the observation side lens. On the other hand, as shown in FIG. 18B, when the image display surface side lens and the observation side lens are negative lenses, light rays emitted from the image display surface become divergent light in the image display surface side lens. As a result, the effective diameter of the intermediate lens is larger than the effective diameters of the image display surface side lens and the observation side lens.

  As described above, in order to reduce the effective diameter of the intermediate lens, it is preferable to configure the optical system so that the refractive powers of the image display surface side lens and the observation side lens are positive.

  In addition, when an eyepiece having a long eye relief and a wide viewing angle is to be realized, there is a possibility that an observation image becomes unclear. In the present invention, an eyepiece lens is configured by using at least two positive lenses and at least two negative lenses, thereby obtaining a high-definition observation image in which axial chromatic aberration and lateral chromatic aberration are well corrected. Can do.

  Here, in the eyepiece lens L of each embodiment, diopter adjustment can be performed by moving all the lenses integrally in the optical axis direction. By moving each lens integrally, fluctuations in coma due to diopter changes can be reduced.

In each example, when the paraxial radius of curvature of the lens surface on the object side of the second lens is R21 and the paraxial radius of curvature of the lens surface on the observation side of the third lens is R32,
−12.00 <(R21 + R32) / (R21−R32) <− 3.00 (1)
The following conditional expression is satisfied.

  When the upper limit value of conditional expression (1) is exceeded, the curvature of any of the paraxial radius of curvature R21 of the lens surface on the object side of the second lens and the paraxial radius of curvature R32 of the lens surface on the observation side of the third lens The radius is too small. As a result, it is difficult to satisfactorily correct the astigmatic difference, which is not preferable.

  When the lower limit of conditional expression (1) is exceeded, the difference between the paraxial radius of curvature R21 of the lens surface on the object side of the second lens and the paraxial radius of curvature R32 of the lens surface on the observation side of the third lens becomes small. Pass. As a result, it becomes difficult to correct coma well, which is not preferable.

In each embodiment, it is preferable to set the numerical range of conditional expression (1) as follows.
-10.50 <(R21 + R32) / (R21-R32) <-3.10 (1a)

More preferably, the numerical range of conditional expression (1) is set as follows.
−9.00 <(R21 + R32) / (R21−R32) <− 3.20 (1b)

Furthermore, in each embodiment, it is more preferable to satisfy one or more of the following conditional expressions.
−0.95 <f2 / f3 <−0.32 (2)
5.0 <νd2 <33.1 (3)
5.0 <νd4 <28.0 (4)

  Here, the focal length of the second lens is f2, the focal length of the third lens is f3, the Abbe number based on the d-line of the second lens material is νd2, and the d-line of the material of the fourth lens is the reference. The Abbe number is νd4.

The Abbe number νd is NF, NC, Nd when the refractive indices of the materials for the F line (486.1 nm), C line (656.3 nm), and d line (587.6 nm) are respectively
νd = (Nd−1) / (NF−NC)
It is a numerical value represented by

  Conditional expression (2) defines the ratio between the focal length f2 of the second lens and the focal length f3 of the third lens. If the upper limit of conditional expression (2) is exceeded and the focal length f2 of the second lens becomes shorter, the refractive power of the second lens becomes too strong. As a result, it is difficult to correct spherical aberration, which is not preferable.

  When the lower limit value of conditional expression (2) is exceeded and the focal length f3 of the third lens is shortened, the refractive power of the third lens becomes too strong. As a result, it is difficult to satisfactorily correct the astigmatic difference, which is not preferable.

  Conditional expression (3) defines the Abbe number νd2 with reference to the d-line of the material of the second lens having a negative refractive power. Chromatic aberration is favorably corrected by disposing a negative lens using a highly dispersed material in an ocular lens having a positive refractive power as a whole.

  If the Abbe number νd2 exceeds the upper limit value of the conditional expression (3), it is difficult to sufficiently correct chromatic aberration in the eyepiece lens, which is not preferable. When the Abbe number νd2 becomes smaller than the lower limit value of the conditional expression (3), the chromatic aberration is excessively corrected, which is not preferable. Moreover, since the material which can be selected as a lens material will be limited, it is not preferable.

  Conditional expression (4) defines the Abbe number νd4 with reference to the d-line of the material of the fourth lens having a negative refractive power. Chromatic aberration is favorably corrected by disposing a negative lens using a highly dispersed material in an ocular lens having a positive refractive power as a whole.

  If the Abbe number νd4 exceeds the upper limit value of the conditional expression (4), it is difficult to sufficiently correct chromatic aberration in the eyepiece lens, which is not preferable. If the Abbe number νd4 becomes smaller than the lower limit value of the conditional expression (4), the chromatic aberration is excessively corrected, which is not preferable. Moreover, since the material which can be selected as a lens material will be limited, it is not preferable.

In each embodiment, it is preferable to set the numerical ranges of conditional expressions (2) to (4) as follows.
−0.93 <f2 / f3 <−0.34 (2a)
10.0 <νd2 <31.5 (3a)
10.0 <νd4 <25.0 (4a)

More preferably, the numerical ranges of the conditional expressions (2) to (4) are set as follows.
−0.90 <f2 / f3 <−0.36 (2b)
15.0 <νd2 <30.3 (3b)
15.0 <νd4 <24.0 (4b)

Further, when the eyepiece L of each embodiment is used in an observation apparatus for observing an image displayed on the image display surface I, the following conditional expression should be satisfied.
0.52 <H / f <0.91 (5)

  Here, the focal length of the entire eyepiece lens system is f, and the diagonal length of the image display surface I is H.

  Conditional expression (5) is a conditional expression that defines the ratio between the diagonal length H of the image display surface I and the focal length f of the eyepiece.

  If the lower limit of conditional expression (5) is exceeded and the focal length f of the eyepiece becomes too long, the viewing angle becomes too narrow, which is not preferable.

  If the upper limit of conditional expression (5) is exceeded and the focal length f of the eyepiece becomes too short, the effective diameter of the lens arranged on the observation side becomes too large. As a result, in the lens arranged on the observation side, many off-axis aberrations such as coma and astigmatism occur, which is not preferable.

In each embodiment, it is preferable to set the numerical range of conditional expression (5) as follows.
0.56 <H / f <0.87 (5a)

More preferably, the numerical range of conditional expression (5) should be set as follows.
0.60 <H / f <0.85 (5b)

  Next, Numerical Examples 1 to 8 respectively corresponding to Embodiments 1 to 8 of the present invention will be shown. In each numerical example, i indicates the order of the optical surfaces from the image display surface side. ri is the radius of curvature of the i-th optical surface (i-th surface), di is the distance between the i-th surface and the i + 1-th surface, and ndi and νdi are the refractions of the material of the i-th optical member with respect to the d-line, respectively. Indicates the rate and Abbe number. r1 represents an image display surface, and r2 represents a surface on the observation side of the plate for protecting the image display surface. The most observation side surface shows the eye point EP in the reference state of the eyepiece lens of each example.

Further, when K is the eccentricity, A4, A6, and A8 are aspherical coefficients, and the displacement in the optical axis direction at the position of the height h from the optical axis is x with respect to the surface vertex, the aspherical shape is
x = (h ² / R) / [1+ [1− (1 + K) (h / R) ² ] ^1/2 ] + A4h ⁴ + A6h ⁶ + A8h ⁸
Is displayed. Where R is the paraxial radius of curvature. A surface with * on the right side of the surface number indicates an aspheric surface. The display of “e-Z” means “10 ^−Z ”.

[Numerical Example 1]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 -65.737 3.95 2.00069 25.5
4 -22.170 3.52
5 * -14.334 3.00 1.63550 23.8
6 * 110.330 0.30
7 * 48.492 6.84 1.53110 55.9
8 * -21.874 1.20
9 * 128.789 1.41 1.63550 23.8
10 * 22.276 1.20
11 39.057 8.21 1.83481 42.7
12 -39.057 27.00
13 (Eyepoint)
Aspheric data 5th surface
K = -7.28787e-001 A 4 = -6.03675e-005 A 6 = 1.77471e-007
6th page
K = 4.51650e + 001 A 4 = -1.11796e-005 A 6 = -6.19143e-008
7th page
K = -4.38548e + 000 A 4 = -2.38798e-005 A 6 = -2.65742e-008
8th page
K = -1.22703e + 000 A 4 = -4.69821e-006 A 6 = 3.91413e-008
9th page
K = -2.69921e + 002 A 4 = -1.52881e-007 A 6 = -4.63945e-009
10th page
K = -4.63925e + 000 A 4 = 4.39848e-006 A 6 = 5.19693e-010
Various data diopters [diopter] -2.0 +2.5 -6.0
Focal length 28.56 28.56 28.56
d 2 9.12 12.79 5.80

[Numerical Example 2]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 -65.913 3.14 2.00069 25.5
4 -48.248 10.11
5 -34.250 3.19 1.76182 26.5
6 -1000.301 1.69
7 * -4010.368 6.95 1.58313 59.4
8 * -44.146 1.21
9 * 161.388 5.20 1.63550 23.8
10 * 44.387 1.20
11 64.814 8.88 1.83481 42.7
12 -64.313 27.00
13 (Eyepoint)
Aspheric data 7th surface
K = 1.33592e + 004 A 4 = -7.84416e-006 A 6 = 7.50739e-009
8th page
K = -6.98689e-001 A 4 = 3.30466e-006 A 6 = -8.53288e-009
9th page
K = -2.65944e + 002 A 4 = -3.33664e-006 A 6 = -9.10796e-009
10th page
K = -9.09514e + 000 A 4 = -5.30646e-006 A 6 = 3.91499e-009
Various data diopters [diopter] -2.0 +0.7 -3.3
Focal length 61.32 61.32 61.32
d 2 21.46 31.12 17.55

[Numerical Example 3]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 -158.559 2.41 2.00069 25.5
4 -77.911 20.00
5 -30.833 8.00 1.95906 17.5
6 -72.834 3.39
7 188.533 7.00 1.83481 42.7
8 -56.340 1.20
9 40.450 1.71 1.84666 23.8
10 23.822 1.20
11 25.956 4.79 1.91082 35.3
12 64.549 27.00
13 (Eyepoint)
Various data diopters [diopter] -2.0 +2.0 -4.0
Focal length 52.34 52.34 52.34
d 2 11.05 21.99 6.18

[Numerical Example 4]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 * -98.827 11.19 1.85135 40.1
4 * -71.371 20.00
5 * -49.765 3.00 1.63550 23.8
6 * -407.575 1.11
7 * -1171.461 7.94 1.49171 57.4
8 * -82.367 1.20
9 * 219.883 3.76 1.63550 23.8
10 * 74.863 1.23
11 * 95.021 8.12 1.80610 40.7
12 * -92.616 27.00
13 (Eyepoint)
Aspheric data 3rd surface
K = 4.54099e-001 A 4 = 3.40725e-008 A 6 = 7.53032e-011 A 8 = -1.51639e-013
4th page
K = 3.40970e-001 A 4 = 8.48720e-008 A 6 = -4.76459e-011 A 8 = 1.79616e-014
5th page
K = 3.53841e-001
6th page
K = -1.00057e + 003
7th page
K = -2.99780e + 003 A 4 = -5.75156e-006 A 6 = 7.03535e-009
8th page
K = -1.18365e + 000 A 4 = 4.34382e-006 A 6 = -5.53385e-009
9th page
K = 1.75400e + 001 A 4 = -2.52412e-006 A 6 = -7.75632e-009
10th page
K = -1.05760e + 001 A 4 = -6.88282e-006 A 6 = 3.02568e-009
11th page
K = 3.83428e + 000
12th page
K = 1.63448e + 000
Various data diopters [diopter] -2.0 +2.0 -4.0
Focal length 91.98 91.98 91.98
d 2 31.59 66.08 20.00

[Numerical Example 5]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 * 166.099 9.26 1.53110 55.9
4 * -34.164 6.60
5 * -28.931 3.82 1.63550 23.8
6 * -93.400 0.47
7 * -153.697 3.79 1.53110 55.9
8 * -50.254 2.12
9 * -40.174 6.83 1.63550 23.8
10 * -56.296 1.20
11 -3131.870 4.55 1.53110 55.9
12 -62.412 1.20
13 110.718 3.36 1.49700 81.5
14 -332.326 27.00
15 (eye point)
Aspheric data 3rd surface
K = -9.59406e + 001 A 4 = -2.43307e-006 A 6 = -5.82983e-009
4th page
K = 3.24062e-001 A 4 = 2.14830e-006 A 6 = 2.81943e-009
5th page
K = 9.32664e-002 A 4 = -5.63898e-007 A 6 = 2.57659e-008
6th page
K = -8.05489e + 000 A 4 = 6.49218e-007 A 6 = -1.63252e-010
7th page
K = -4.96939e + 001 A 4 = -1.17845e-006 A 6 = -4.58865e-009
8th page
K = 2.90402e-001 A 4 = -2.46377e-006 A 6 = 5.28440e-009
9th page
K = -1.87452e-001 A 4 = 1.66992e-006 A 6 = -7.39182e-009
10th page
K = 2.96336e + 000 A 4 = 4.16642e-007 A 6 = 1.08928e-009
Various data diopters [diopter] -2.0 +2.0 -4.0
Focal length 52.34 52.34 52.34
d 2 22.29 33.23 17.21

[Numerical Example 6]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 -1201.003 20.00 1.48749 70.2
4 -89.718 20.00
5 * -64.550 3.06 1.63550 23.8
6 * -160.023 2.00
7 * -230.109 3.54 1.53110 55.9
8 * -119.762 1.20
9 * -86.800 12.72 1.63550 23.8
10 * -103.753 1.20
11 5354.752 4.23 1.60311 60.6
12 -123.568 1.20
13 178.678 3.96 1.49700 81.5
14 -351.151 27.00
15 (eye point)
Aspheric data 5th surface
K = 2.64919e + 000 A 4 = -7.42759e-007
6th page
K = -6.77987e + 001 A 4 = -2.49183e-008
7th page
K = 6.98083e + 001 A 4 = -1.18509e-006
8th page
K = 5.02189e + 000 A 4 = -2.98254e-006 A 6 = -1.01200e-009
9th page
K = 2.92913e + 000 A 4 = 1.34769e-006
10th page
K = 1.50370e + 000 A 4 = -8.31493e-007
Various data diopters [diopter] -2.0 +2.0 -4.0
Focal length 104.68 104.68 104.68
d 2 32.12 76.83 17.13

[Numerical Example 7]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51000 60.0
2 ∞ (variable)
3 * 136.125 8.69 1.69350 53.2
4 * -43.222 8.67
5 * -28.738 3.00 1.63550 23.8
6 * -89.027 0.30
7 * -231.429 5.74 1.53110 55.9
8 * -46.578 2.68
9 * -39.537 2.66 1.63550 23.8
10 * -55.894 1.84
11 * -2299.162 5.94 1.53110 55.9
12 * -60.213 1.20
13 110.718 4.00 1.55332 71.7
14 -332.326 27.00
15 (eye point)
Aspheric data 3rd surface
K = -6.07439e + 000 A 4 = -1.82896e-006 A 6 = -5.07089e-009
4th page
K = 5.99930e-001 A 4 = 1.41427e-006 A 6 = 4.25770e-010
5th page
K = 1.13826e-001 A 4 = -6.11987e-007 A 6 = 2.58066e-008
6th page
K = -7.86704e + 000 A 4 = 6.27492e-007 A 6 = -5.81898e-010
7th page
K = -3.07481e + 001 A 4 = -8.80513e-007 A 6 = -3.57889e-009
8th page
K = 5.53963e-001 A 4 = -2.76657e-006 A 6 = 4.45282e-009
9th page
K = -1.40844e-001 A 4 = 1.47140e-006 A 6 = -7.32877e-009
10th page
K = 3.06010e + 000 A 4 = 6.99258e-007 A 6 = 1.21727e-009
11th page
K = 1.00225e + 004 A 4 = -2.66396e-007 A 6 = 8.58565e-011 A 8 = 9.72106e-013
12th page
K = -3.51427e-001 A 4 = 2.36708e-007 A 6 = 2.33340e-010 A 8 = -4.05287e-013
Various data diopters [diopter] -2.0 +2.0 -4.0
Focal length 45.99 45.99 45.99
d 2 19.29 27.62 15.12

[Numerical Example 8]
Unit mm
Surface data surface number rd nd νd
1 ∞ 0.70 1.51633 64.1
2 ∞ (variable)
3 547.471 4.04 1.71300 53.9
4 -23.889 2.74
5 -14.779 1.14 1.69895 30.1
6 39.283 9.03 1.91082 35.3
7 -24.063 (variable)
8 -16.665 1.09 1.80809 22.8
9 -94.061 4.60 1.83481 42.7
10 -22.997 0.17
11 184.850 2.92 1.88300 40.8
12 -58.904 27.00
13 (Eyepoint)
Various data diopters [diopter] -2.0 +2.4 -5.8
Focal length 28.97 29.87 27.10
d 2 6.58 9.93 4.95
d 7 8.39 10.64 3.20

  Subsequently, the numerical values of the conditional expressions described above in the respective numerical examples are shown in Table 1.

  Next, an embodiment of a video camera using the eyepiece shown in each example will be described with reference to FIG.

  In FIG. 17, reference numeral 10 denotes a video camera body, 11 denotes an imaging optical system that forms a subject image on an imaging element (not shown), and 12 denotes a sound collecting microphone. Reference numeral 13 denotes an observation apparatus (electronic viewfinder) for observing a subject image displayed on an image display element (not shown) through the eyepiece of the present invention. The image display element is constituted by a liquid crystal panel or the like, and an object image or the like formed by the photographing optical system 11 is displayed on the image display element.

  As described above, by applying the eyepiece of the present invention to an imaging apparatus such as a video camera, an imaging apparatus having a long eye relief, a wide viewing angle, a small size, and high optical performance can be obtained.

L Eyepiece I Image display surface EP Eyepoint

Claims (9)

In order from the object side to the observation side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens having a negative refractive power,
When the radius of curvature of the lens surface on the object side of the second lens is R21 and the radius of curvature of the lens surface on the observation side of the third lens is R32,
−12.00 <(R21 + R32) / (R21−R32) <− 3.00
An eyepiece that satisfies the following conditional expression: When the focal length of the second lens is f2, and the focal length of the third lens is f3,
−0.95 <f2 / f3 <−0.32
The eyepiece according to claim 1, wherein the following conditional expression is satisfied. When the Abbe number of the material of the second lens is νd2,
5.0 <νd2 <33.1
The eyepiece according to claim 1, wherein the following conditional expression is satisfied. When the Abbe number of the material of the fourth lens is νd4,
5.0 <νd4 <28.0
The eyepiece according to claim 1, wherein the following conditional expression is satisfied.   In order from the object side to the observation side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, and a first lens having a positive refractive power. The eyepiece lens according to any one of claims 1 to 4, wherein the eyepiece lens comprises five lenses.   In order from the object side to the observation side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, and a first lens having a positive refractive power. The eyepiece according to any one of claims 1 to 4, comprising five lenses and a sixth lens having a positive refractive power.   The eyepiece lens according to any one of claims 1 to 6, wherein all the lenses move together in diopter adjustment. An image display element that displays an image, and an observation apparatus that observes an image displayed on the image display surface of the image display element using the eyepiece according to any one of claims 1 to 7,
When the focal length of the whole eyepiece lens system is f and the diagonal length of the image display surface is H,
0.52 <H / f <0.91
An observation apparatus that satisfies the following conditional expression: An image sensor;
An imaging optical system for forming an object image on the imaging device;
An image display element for displaying the object image;
An imaging apparatus comprising the eyepiece according to claim 1, which is used for observing an image displayed on the image display element.