JP2008191647A - Optical element, viewfinder, photometric optical system and photographing optical system, imaging method, observation method, photometric method and photographing method - Google Patents

Abstract

An optical element in which a liquid container part and an optical axis deflection surface are integrally formed is provided.
A first liquid (32) and an insulating second liquid (33) that does not mix with the first liquid (32) are sealed in a liquid container part (22), and a voltage applied to the liquid container part (22) is changed. Thus, it has a liquid lens capable of changing the shape of the boundary surface 34 between the first liquid 32 and the second liquid 33, and a deflection member having an optical axis deflection surface, With respect to the optical axis of the liquid lens penetrating the boundary surface between the first liquid and the second liquid, the liquid lens is disposed on at least one of the incident light side and the emission light side.
[Selection] Figure 4

Description

  The present invention relates to an optical element, a finder optical system, a photometric optical system, and a photographing optical system including the optical element, and an imaging method, an observation method, a photometric method, and a photographing method using the optical element.

  Conventionally, in an optical system that performs focusing, zooming, diopter adjustment, etc., focusing, zooming, or diopter adjustment has been performed by moving a fixed focal length lens in the optical axis direction. In order to move the fixed focal length lens, there is a power source such as a motor and a mechanical mechanism such as a gear or a cam for converting the driving force from the power source into movement of the fixed focal length lens in the optical axis direction. Although necessary, these mechanical mechanisms have problems such as an increase in the size of a camera and the like, and generation of driving sound.

  As a method to solve these problems, a variable focal length lens using electrowetting phenomenon, a variable shape mirror that can change the focal length by changing the surface shape, etc. are used electrically without a power source or mechanical mechanism. In recent years, many optical systems capable of performing focusing, zooming, diopter adjustment, and the like have been proposed (see, for example, Patent Document 1 or 2).

JP 2001-249282 A

JP 2004-198636 A

  However, when a variable focal length lens is provided in an optical system having a deflecting member such as a reflecting surface or a prism in the optical path, it is necessary to insert the variable focal length lens separately from the deflecting member such as a reflecting member or a prism. The size of the optical system cannot be reduced, the number of parts is increased by that amount, it is difficult to align the optical axis between the reflecting member and the variable focal length lens when assembling the optical system, and the occurrence of ghosts and flares due to the increased optical surface There is a problem that there are many. Further, when the shape change is performed on the reflecting surface, there is a problem that the influence on the optical aberration due to the shape error of the variable reflecting surface becomes large.

  The present invention has been made in view of such a problem, and it is not necessary to insert separately from a deflecting member such as a reflecting member or a prism, the size of the optical system can be reduced, the number of parts can be reduced, and the optical system can be reduced. An optical element that does not require alignment of the optical axis with the deflecting member during assembly, has little ghost or flare, and has little influence on optical aberration due to variable surface shape error, and a finder optical system and a photometric optical system having this optical element And an imaging optical system, and an imaging method, an observation method, a photometry method, and an imaging method using the same.

  In order to solve the above problems, an optical element according to a first aspect of the present invention includes a first liquid and a second liquid that is not mixed with the first liquid, and is in a container (for example, the liquid container portion 22 in the embodiment). And a liquid lens capable of changing the shape of the boundary surface between the first liquid and the second liquid by changing a physical quantity applied to the container and an optical axis deflection surface (for example, reflection in the embodiment) A deflecting member having a surface 23a), the optical axis deflecting surface being on the incident ray side and the exit ray side with respect to the optical axis of the liquid lens passing through the boundary surface between the first liquid and the second liquid. At least one is disposed.

Further, it is preferable that the optical axis deflecting surface is configured in one or more prism members.
Moreover, it is preferable to have an optical member in contact with the first liquid or the second liquid, and the optical member and the prism member are joined.

  For example, it is preferable that the first liquid has conductivity, the second liquid has insulation, and the physical quantity is a voltage.

  Moreover, it is preferable that the inner wall surface of the liquid lens is configured to be in contact with the boundary surface on the entire circumference around the optical axis of the liquid lens.

  An electrode provided on a member that forms the inner wall surface of the liquid lens (for example, the second electrode 27 in the embodiment), and an insulating means provided between the electrode and the first liquid and the second liquid (for example, The second insulator 29) in the embodiment is preferably configured to change the interface shape by applying a voltage between the first liquid and the electrode.

  Note that the first liquid and the second liquid preferably have substantially the same density.

  Further, the first liquid and the second liquid are preferably configured to have different refractive indexes.

At this time, at least one of the optical axis deflecting surfaces is a refracting surface, and an angle between the refracting surface and the optical axis of the liquid lens is θ [degree], and the boundary from the refracting surface on the optical axis of the liquid lens. When the length to the surface is d and the maximum diameter of the contact portion where the boundary surface and the inner wall surface of the liquid lens are in contact is DL,
θ <88
d / DL> 0.30
Is preferably satisfied.

In addition, at least one of the optical axis deflecting surfaces is a reflecting surface, and the reflecting surface is located on the incident surface side with respect to the boundary surface, and is a boundary from the incident surface on the optical axis including the optical axis of the liquid lens. When the length to the surface is d1, and the maximum diameter of the contact portion where the boundary surface and the inner wall surface of the liquid lens are in contact is DL,
d1 / DL> 0.50
Is preferably satisfied.

Alternatively, at least one of the optical axis deflecting surfaces is a reflecting surface, and the reflecting surface is located on the exit surface side of the boundary surface, and is bounded by the exit surface on the optical axis including the optical axis of the liquid lens. When the length to the surface is d2, and the maximum diameter of the contact portion where the boundary surface is in contact with the inner wall surface of the liquid lens is DL,
d2 / DL> 0.50
Is preferably satisfied.

  The inner wall surface of the liquid lens is preferably formed rotationally symmetrical with respect to the optical axis of the liquid lens.

  The liquid lens container is preferably a deflection member.

  The finder optical system according to the first aspect of the present invention includes an objective lens group having a positive refractive power (for example, the objective lens unit 41 and the field lens 43 in the embodiment) and an eyepiece group having a positive refractive power ( For example, the optical element 47 and the eyepiece lens unit 48) according to the embodiment are configured, and any one of the above-described optical elements is arranged in at least one optical path of the objective lens group or the eyepiece lens group.

  In the finder optical system according to the first aspect of the present invention, the optical element is disposed in the optical path of the eyepiece lens group, and the diopter adjustment is performed by changing the boundary surface of the liquid lens of the optical element. Preferably it is comprised.

  A finder optical system according to the second aspect of the present invention includes a focusing screen provided in the vicinity of the image plane, a variable focal length element that is one of the optical elements described above, and an eyepiece group.

  The finder optical system according to the second aspect of the present invention is preferably configured to adjust diopter by changing the boundary surface of the optical element. Further, it is preferable that the telecentricity adjustment of the emitted light from the optical element is performed by changing the boundary surface of the optical element. Furthermore, it is preferable to have a field lens (for example, the Fresnel lens 52 in the embodiment).

  A photometric optical system according to the present invention includes a field lens (for example, Fresnel lens 72 in the embodiment) and a focusing plate provided in the vicinity of an image forming surface, an image inverting optical system, and any one of the optical elements described above. A variable focal length element disposed on the light exit side of the image inverting optical system, and an optical system having a positive refractive power disposed on the light exit side of the variable focal length element (for example, the positive lens in the embodiment) 84).

  In addition, the photographing optical system according to the present invention has a positive refractive power as a whole, and includes at least one of the above-described optical elements in the optical path.

  Note that the imaging method according to the present invention is a method of forming an image using any of the above-described optical elements, and the observation method according to the present invention is to observe an object using any of the above-described finder optical systems. The photometric method according to the present invention is a method of performing photometry with the above-described photometric optical system, and the photographing method according to the present invention is a method of photographing with the above-described photographing optical system.

  When the optical element, the finder optical system, the photometric optical system, the photographing optical system, the imaging method, the observation method, the photometric method, and the photographing method according to the present invention are configured as described above, a deflecting member such as a reflecting member or a prism is provided. There is no need to insert it separately, the size of the optical system can be reduced, the number of parts can be reduced, optical axis alignment with the deflection member during assembly of the optical system is not required, ghosts and flares are less likely to occur, and the variable surface The influence on the optical aberration due to the shape error can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, the configuration of the optical element according to the embodiment will be described with reference to FIGS. 1 and 2. Here, FIG. 1 shows a sectional view of the optical element 1 according to the first embodiment, and FIG. 2 shows a plan view. The optical element 1 includes a liquid container part 2 and a prism part 3.

  The liquid container portion 2 includes a first container 4 in which a conductive material is formed in a cylindrical bowl shape, and a second container 5 in which the conductive material is formed in a cylindrical bowl shape, for example, an insulating material such as rubber. The formed packing 6 sandwiched between the first container 4 and the second container 5, the second electrode 7 in which the conductive material is formed in a cylindrical shape, and the light transmitting material is formed in a disk shape. The first optical window member 8 and the light transmitting material are formed in a two-stage cylindrical shape including a disk-shaped base portion 9a and a connecting portion 9b which is concentrically arranged with a smaller diameter than the base portion 9a and protrudes upward. The second optical window member 9 is formed. Note that, as will be described later, the first container 4 is also used as an electrode, and therefore will be referred to as the first electrode 4 in the following description.

  The bottom portion 5a of the second container 5 is provided with an opening window 5b formed in a circular shape, and the connection portion 9b of the second optical window member 9 inserted into the second container 5 is connected to the opening window 5b. To the outside of the second container 5. Note that the upper surface of the base portion 9 a of the second optical window member 9 is in contact with the lower surface of the bottom portion 5 a of the second container 5 and is connected by an adhesive or a sealer 10. Further, the prism portion 3 described above is bonded to the upper surface of the connection portion 9b of the second optical window member 9.

  The second electrode 7 is formed with a through hole penetrating in the vertical direction. The second electrode 7 includes an upper portion 7a having a large diameter and a lower portion 7b having a small diameter. The outer diameter of the second electrode 7 is formed to be approximately the same as the inner diameter of the second container 5. The second electrode 7 is inserted into the second container 5 from the upper part 7 a side, and the bottom surface 5 a of the second container 5 is The lower surface and the upper surface of the upper portion 7a of the second electrode 7 are attached in contact with each other. At this time, the height of the through-hole formed in the upper portion 7a is substantially the same as the height (thickness) of the base portion 9a of the second optical window member 9, and the base portion 9a is the second container. 5 and the upper surface of the lower portion 7b of the second electrode 7.

  On the other hand, the bottom portion 4a of the first container 4 is also provided with an opening window 4b formed in a circular shape and penetrating vertically, and the first optical window member 8 inserted into the first container 4 closes the opening window 4b. It is attached as follows. At this time, the bottom surface of the outer peripheral portion of the first optical window member 8 and the top surface of the bottom portion 4 a of the first container 4 are in contact with each other and are connected by an adhesive or a sealer 11. And the 2nd container 5 is inserted in the 1st container 4 and these are combined so that the opening part 4c of the 1st container 4 and the opening part 5c of the 2nd container 5 may be match | combined on both sides of the packing 6. FIG.

  In a space surrounded by the first container 4 and the second container 5, a conductive lithium chloride aqueous solution (referred to as “first liquid 12”), and insulating silicon having the same density as the first liquid 12. Oil (this is called “second liquid 13”) is filled and enclosed. At this time, the first liquid 12 and the second liquid 13 are not mixed, and a boundary surface 14 is formed by surface tension, and these liquids 12 and 13 are arranged with the boundary surface 14 as a boundary to constitute a liquid lens. ing. In addition, since the first liquid 12 and the second liquid 13 are configured with the same density, gravity does not affect the boundary surface 14 at all, and thus the influence of the gravity direction on the boundary surface 14 can be avoided. In addition, mixing by vibration can be avoided.

  1 and 2, the inner wall surface 7c of the lower portion 7b of the second electrode 7 is formed rotationally symmetric, and the optical axis X of the liquid lens can be defined as a rotationally symmetric axis with respect to the inner wall surface 7c. . In FIG. 1, the optical axis X of the liquid lens coincides with the optical axis of incident light incident from the lower side to the upper side (incident light optical axis I), and penetrates the boundary surface 14. The light beam incident along the optical axis X (incident light beam optical axis I) of the liquid lens is transmitted through the first optical window member 8, the first liquid 12, the second liquid 13, and the second optical window member 9 to be a prism. The light enters the portion 3, is totally reflected by the reflection surface 3 a that is an optical axis deflection surface, is guided leftward in FIG. 1, and is emitted from the prism portion 3 as a light beam defined as an emission light beam optical axis O.

  In the optical element 1, the boundary surface 14 between the first liquid 12 and the second liquid 13 is in contact with the inner wall surface 7 c on the entire circumference around the optical axis X of the liquid lens. An insulating film (not shown) is provided on the outer surface of the second electrode 7 forming the inner wall surface 7c, and the first and second liquids 12 and 13 and the second electrode 7 are insulated. On the other hand, the first electrode (first container) 4 that is insulated via the second electrode 7 and the packing 6 is in contact with the first liquid 12 that is a conductive liquid, and the first liquid 12 can be energized. It has become. Therefore, by applying a voltage to the first electrode 4 and the second electrode 7, the voltage can be applied to the second electrode 7 forming the first liquid 12 and the inner wall surface 7c. Thus, the surface tension between the boundary surface 14 and the inner wall surface 7c can be changed. Thereby, the boundary surface shape can be changed by the surface tension of the boundary surface 14, and the boundary surface shape can be changed with respect to the change in voltage. Here, the refractive index at the d-line of the first liquid 12 is n = 1.41, and the refractive index at the d-line of the second liquid 13 is n = 1.55. Thus, the focal length of the entire optical element 1 can be changed.

  In the above description, the case where the inner wall surface 7c of the second electrode 7 is formed to be rotationally symmetric has been described. However, the present embodiment is not limited to this shape. For example, the shape of the inner wall surface 7c is It is also possible to configure a plane symmetry including the optical axis X of the liquid lens. Alternatively, the inner wall surface 7c may be asymmetric. Further, by using two liquids having substantially the same refractive index and different Abbe numbers as the first liquid 12 and the second liquid 13, the chromatic aberration of the entire optical element 1 is caused by the change of the boundary surface shape accompanying the voltage change. Can be configured to be changeable.

  FIG. 3 shows a cross-sectional view of an optical element 1 ′ according to the second embodiment. In addition, in this 2nd Example, the same member as the 1st Example attaches | subjects the same code | symbol, and abbreviate | omits detailed description. In the optical element 1 ′ according to the second embodiment, the liquid container portion 2 ′ is formed in a two-stage cylindrical shape in which the first optical window member 8 ′ is also composed of a base portion 8 a ′ and a connection portion 8 b ′. A first prism portion 15 is bonded to the lower surface of the connection portion 8a ′ of the first optical window member 8 ′ (in order to distinguish it from the first prism portion 15, the prism portion 3 is referred to as a “second prism portion”. Called). The light beam incident along the incident light beam optical axis I from the left side of the first prism unit 15 is totally reflected by the reflection surface 15a which is an optical axis deflection surface, and is liquid container unit 2 'along the optical axis X of the liquid lens. 1 is further reflected by the reflecting surface 3a of the second prism unit 3 and guided to the left in FIG. 1, and is emitted from the second prism unit 3 as a light beam defined as an outgoing light beam optical axis O. Is done. In the second embodiment, the same effects as in the first embodiment can be obtained.

  FIG. 4 shows an optical element 21 according to the third embodiment. The optical element 21 includes a liquid container part 22 and a prism part 23.

  In the third embodiment, the liquid container portion 22 includes a first electrode 24 in which a conductive material is formed in a cylindrical bowl shape, a container 25 in which an insulating material such as plastic is formed in a cylindrical shape, and an insulating material. A first insulator 26 formed in a cylindrical shape, a second electrode 27 formed of a conductive material in a double cylindrical shape, an optical window member 28 formed of a light transmitting material in a disk shape, and An insulating material that transmits light is composed of a second insulator 29 formed in a cylindrical bowl shape. The second electrode 27 has a U-shaped cross section and is attached so as to cover the inner peripheral surface, upper surface, and outer peripheral surface of the container 25. Further, the outer diameter of the first insulator 26 is formed to be substantially the same as the inner diameters of the second electrode 27 and the container 25, and the first insulation with respect to the inner peripheral surfaces of the second electrode 27 and the container 25. A body 26 is inserted and attached. Furthermore, the outer diameter of the second insulator 29 is formed to be approximately the same as the inner diameter of the first insulator 26, and the first insulator 29 is directed so that the opening 29a of the second insulator 29 faces downward. It is inserted into the body 26 and attached.

  In a state where the second electrode 27, the first insulator 26, and the second insulator 29 are attached to the container 25, their upper surfaces are located on substantially the same plane, and the prism portion is located with respect to the upper surface. 23 is joined. The lower surfaces of the container 25, the first insulator 26, and the second insulator 29 are also located on substantially the same plane, and the first electrode 24 is joined to the lower surface. A circular opening window 24b is provided on the bottom 24a of the first electrode 24. The inner diameter of the opening window 24b is formed slightly smaller than the inner diameter of the opening 29a of the second insulator 29. The rotational symmetry axis (the optical axis X of the liquid lens described later) coincides with the opening 24a and the opening 29a. Further, the inner diameter of the first electrode 24 and the outer diameter of the optical window member 28 are formed to be substantially the same size, and the optical window member 28 is inserted and attached to the first electrode 24.

  In the space surrounded by the second insulator 29, the first electrode 27, and the optical window member 28, as in the first embodiment, the first liquid (conductive lithium chloride aqueous solution) 32 having the same density, A second liquid (insulating silicon oil) 33 is filled and enclosed. Also in the third embodiment, the first liquid 32 and the second liquid 33 are not mixed, and the boundary surface 24 including a convex curved surface state on the first liquid 32 side is formed by the surface tension. Further, since the first liquid 32 and the second liquid 33 are composed of the same density liquid, it is possible to avoid the influence of the gravitational direction on the boundary surface 34 and mixing due to vibration. Furthermore, the inner wall surface 29b of the second insulator 29 is formed rotationally symmetrical, and the rotational symmetry axis with respect to the inner wall surface 29b coincides with the optical axis X of the liquid lens. The optical axis X of the liquid lens penetrates the boundary surface 34 in alignment with the incident light optical axis I incident from below to above. Therefore, the light beam incident on the liquid container portion 22 along the incident light beam optical axis I is totally reflected by the reflecting surface 23a which is a light beam deflecting surface of the prism portion 23 and is emitted as a light beam defined by the emitted light beam optical axis O. Is done.

  Also in the optical element 21, the boundary surface 34 between the first liquid 32 and the second liquid 33 is in contact with the inner wall surface 29b on the entire circumference around the optical axis X of the liquid lens. The second electrode 27 is insulated from the first liquid 32 and the second liquid 33 by the first and second insulators 26 and 29, while the opening 24 b of the first electrode 24 is formed in the first liquid 32. It is in contact and electrically connected. Therefore, by applying a voltage to the first electrode 24 and the second electrode 27, the surface tension between the boundary surface 34 and the inner wall surface 29b can be changed, and the boundary surface shape can be changed in response to a change in voltage. It has become a structure.

  In the third embodiment, the refractive index of the first liquid 32 at the d-line is n = 1.44, and the refractive index of the second liquid 33 at the d-line is n = 1.51. The focal length of the entire optical element 21 can be changed by a change in the shape of the boundary surface accompanying a change in voltage. In addition, the shape of the inner wall surface 29b can be configured not only rotationally symmetric but also symmetric with respect to the plane including the optical axis X of the liquid lens. Further, as the first liquid 32 and the second liquid 33, the refractive index is almost equal. By using two liquids having the same Abbe number but different Abbe numbers, it is possible to change the aberration of the entire optical element 21 by changing the shape of the boundary surface according to the voltage change.

  FIG. 5 shows a cross-sectional view of an optical element 21 ′ according to the fourth embodiment. In addition, in this 4th Example, the same member as the 3rd Example attaches | subjects the same code | symbol, and abbreviate | omits detailed description. In the optical element 21 'according to the fourth embodiment, the first electrode 24' constituting the liquid container portion 22 'is formed in a disc shape, and the opening 29a and its rotational symmetry are formed as in the third embodiment. An opening window 24b ′ having an axis (which coincides with an optical axis X of a liquid lens described later) is formed. A first prism portion 35 is bonded to the lower surface of the first electrode 24 '(the prism portion 23 is referred to as a "second prism portion"). Therefore, the light beam incident along the incident light beam optical axis I from the left side of the first prism unit 35 is totally reflected by the reflection surface 35a which is an optical axis deflection surface, and is liquid container unit along the optical axis X of the liquid lens. The light beam is incident on 22 ', further totally reflected by the reflecting surface 23a of the second prism portion 23, and guided to the left in FIG. As injected. In the fourth embodiment, the same effects as in the third embodiment can be obtained.

  In the third embodiment, since the side portion 24c of the first electrode 24 extends along the side surface of the optical window member 28, a voltage is applied by connecting a power cable or the like to the side portion 24c. However, in the fourth embodiment there is no such side. However, as shown in FIG. 6, by making the first electrode 24 'rectangular, a portion that does not overlap with the container 25 or the like formed in rotational symmetry in plan view can be formed at the four corners. Can be connected.

  FIG. 7 shows a case where the optical element of the present embodiment is applied to a finder optical system (real image type finder optical system) as a fifth example. The viewfinder optical system 40 includes, in order from the object side, an objective lens unit 41 including a biconcave lens, a biconvex lens, and a negative meniscus lens having a convex surface facing the object side, a mirror 42, a field lens 43, a roof prism 44, a prism The optical element 47 includes a part 45 and a liquid container part 46, and an eyepiece 48 which is a biconvex lens. In the finder optical system 40 according to the fifth embodiment, the optical element 47 is used for adjusting the diopter of the eyepiece, and the combined focal length of the eyepiece 49 comprising the optical element 47 and the eyepiece 48 is used. Diopter adjustment is realized by changing the afocal degree of the exit configuration from the finder optical system. Therefore, in the optical element 47, the prism portion 45 is used as a function of correcting the optical path difference in the left-right direction in FIG. 7 generated in the roof prism 44 while guiding the emitted light from the roof prism 44 to the eyepiece lens 48. As shown in FIG. 8, an air gap portion 49 is provided between the roof prism 44 and the prism portion 45, and the optical axis is bent at the air gap portion 49. That is, it can be seen that the optical axis deflection surface (refractive surface) 45a of the prism portion 45 functions to bend the incident light beam optical axis I.

  FIG. 9 shows a case where the optical element of the present embodiment is applied to a finder optical system (single-lens reflex finder optical system) as a sixth example. The finder optical system 50 includes, in order from the object side, a mirror 51, a Fresnel lens 52, a focusing screen 53, a liquid container part 54, a pentaprism part 55 joined to the liquid container part 54, a biconcave lens, It is composed of a biconvex lens and an eyepiece unit 57 composed of a negative meniscus lens having a convex surface facing the object side. In the finder optical system 50 according to the sixth embodiment, the optical element 56 includes a liquid container portion 54 and a pentaprism portion 55, and is used as a field lens and an image inverting optical element. The optical axis deflection surfaces of the optical element 56 are the roof reflection surface 55a and the reflection surface 55b. The finder optical system 50 is used as an eye relief changing function of the finder optical system 50 as a result of changing the telecentricity of the emitted light by the focal length conversion function of the optical element 56.

  FIG. 10 shows a case where the optical element of this embodiment is applied to a finder optical system (single-lens reflex finder optical system) as a seventh example. The finder optical system 60 includes, in order from the object side, a mirror 61, a Fresnel lens 62, a focusing screen 63, a pentaprism unit 64, a liquid container unit 65 joined to the pentaprism unit 64, a biconvex lens, The eyepiece lens unit 67 includes a negative meniscus lens having a convex surface facing the object side. In the finder optical system 60 according to the seventh embodiment, the optical element 66 includes a pentaprism part 64 and a liquid container part 65, and is used as a part of the eyepiece lens system and the image reversal optical element as described above. Yes. The optical axis deflection surfaces of the optical element 66 are the roof reflection surface 64a and the reflection surface 64b. The finder optical system 60 is used as a diopter adjusting mechanism by changing the diopter from the eyepiece lens unit 67 by the focal length conversion function of the optical element 66.

  11 and 12 show a case where the optical element of the present embodiment is applied to a photometric optical system attached to the finder optical system as an eighth example. The viewfinder optical system 70 includes, in order from the object side, a mirror 71, a Fresnel lens 72, a focusing screen 73, a pentaprism unit 74, a biconcave lens, a biconvex lens, and a negative meniscus lens having a convex surface facing the object side. An eyepiece unit 75 is configured, and a photometric optical system 80 is attached to the exit side surface of the pentaprism unit 74. The photometric optical system 80 includes, in order from the object side, an optical element 83 including a prism part 81 and a liquid container part 82, a positive lens 84 that is a biconvex lens, a prism 85, and a photometric sensor 86. The optical axis deflection surface 83 is the reflecting surface 81 a of the prism portion 81. In the photometric optical system 80 according to the eighth embodiment, the optical element 83 is used as an optical system for guiding a light beam to the photometric sensor 86 and an angle of view changing means. The angle of view on the sensor 86 can be changed, whereby the photometric range can be changed.

  FIG. 13 shows a case where the optical element of the present embodiment is applied to a photographing optical system as a ninth example. The photographing optical system 90 includes, in order from the object side, a first lens group 94 including a negative meniscus lens having a convex surface directed toward the object side, a prism 91 and a liquid container portion 92, a biconcave lens, a biconcave lens, and a biconvex lens. A second lens group 95, a third lens group 96 composed of a biconvex lens, a biconvex lens and a biconcave lens, a fourth lens group 97 composed of a biconvex lens, a biconvex lens and a biconcave lens, an optical low-pass filter 98, and an image sensor 99. Consists of In the photographing optical system 90 according to the ninth embodiment, the optical element 93 includes a prism part 91 and a liquid container part 92, and is used as a compensator for a zoom lens, focusing, and a beam bending optical system. The optical axis deflection surface of the optical element 93 is the reflection surface 91a of the prism portion 91, and the photographing optical system 90 converts the incident light to the second lens group 95 by the focal length conversion function of the optical element 93. The zoom lens compensator and focus are changed.

  By the way, in this embodiment, when at least one optical axis deflecting surface is a refracting surface, the angle between the optical axis deflecting surface and the optical axis of the liquid lens is θ [degree], and the liquid lens When the length from the optical axis deflection surface to the boundary surface in at least one state along the optical axis is d, and the maximum diameter of the contact portion between the boundary surface and the inner wall surface of the liquid lens is DL, the following conditional expression It is desirable to satisfy (1) and (2).

θ <88 (1)
d / DL> 0.30 (2)

  Conditional expression (1) is a conditional expression for reducing the occurrence of ghosts due to the refractive surface in the optical element according to the present embodiment. If the upper limit value of the conditional expression (1) is exceeded, the refractive surface that is the optical axis deflection surface and the surface of the optical member having the optical axis deflection surface that contacts the liquid, or the first liquid and the second liquid. Ghost is likely to occur between the boundary surface and the ghost and flare generated by the optical element and the optical system. More preferably, the upper limit value of conditional expression (1) is 85 [degrees], more preferably 80 [degrees].

  Conditional expression (2) is a conditional expression for reducing the occurrence of ghost due to multiple reflection of the refractive surface in the optical element according to the present embodiment. If the lower limit value of the conditional expression (2) is not reached, the refracting surface that is the optical axis deflection surface and the surface of the optical member that has the optical axis deflection surface in contact with the liquid, or the first liquid and the second liquid. A ghost due to multiple reflection is likely to occur between the boundary surface and the ghost and flare generated by the optical element and the optical system. More preferably, the lower limit value of conditional expression (2) is 0.35, more preferably 0.40.

  The configuration having the refracting surface as the optical deflection surface is realized in the fifth embodiment shown in FIG. 7, and the specifications and values corresponding to the conditions in the fifth embodiment are shown in Table 1 below.

(Table 1)
[Fifth embodiment]
d = 4.5mm
DL = 7.5mm
(1) θ = 58 degrees (2) d / DL = 0.60

  As described above, in the fifth embodiment, the conditional expressions (1) and (2) are all satisfied.

  Further, in this embodiment, when at least one optical axis deflecting surface is a reflecting surface, and this reflecting surface is closer to the incident surface side of the optical element than the boundary surface, the optical axis of the liquid lens is included. When the length from the incident surface of this optical element along the optical axis to the boundary surface in at least one state is d1, and the maximum diameter of the contact portion where the boundary surface and the inner wall surface of the liquid lens are in contact is DL, It is desirable to satisfy conditional expression (3).

                    d1 / DL> 0.50 (3)

  Conditional expression (3) is for reducing the occurrence of a ghost due to the incident surface on the optical element in the optical element according to the present embodiment. If the lower limit of conditional expression (3) is not reached, the incident surface to the optical element and the surface of the optical member having the optical axis deflection surface that contacts the liquid, or the boundary surface between the first liquid and the second liquid Ghosts are likely to occur between the optical elements and the ghosts and flares generated by the optical elements and optical systems. More preferably, the lower limit value of conditional expression (3) is 0.70, more preferably 0.90.

  In this way, the structure having the reflecting surface as the optical deflection surface and the reflecting surface being closer to the incident surface side of the optical element than the boundary surface includes the second embodiment shown in FIG. Tables 2 and 2 below show the specifications and values corresponding to the conditions in the eighth and ninth embodiments.

(Table 2)
[Second Embodiment]
d1 = 9.0mm
DL = 5.9mm
(3) d1 / DL = 1.52
[Fourth embodiment]
d1 = 10.7mm
DL = 6.2mm
(3) d1 / DL = 1.73
[Seventh embodiment]
d1 = 71.2mm
DL = 14.5mm
(3) d1 / DL = 4.91
[Eighth embodiment]
d1 = 2.8mm
DL = 1.8mm
(3) d1 / DL = 1.56
[Ninth embodiment]
d1 = 22.7mm
DL = 16.0mm
(3) d1 / DL = 1.42

  Thus, in these examples, all the conditional expressions (3) are satisfied.

  Alternatively, in this embodiment, when at least one optical axis deflecting surface is a reflecting surface, and the reflecting surface is closer to the exit surface side of the optical element than the boundary surface, the optical axis of the liquid lens is included. When the length from the exit surface of the optical element to the boundary surface in at least one state along the optical axis is d2, and the maximum diameter of the contact portion between the boundary surface and the inner wall surface of the liquid lens is DL, It is desirable to satisfy conditional expression (4).

                    d2 / DL> 0.50 (4)

  Conditional expression (4) is for reducing the occurrence of a ghost due to the exit surface of the optical element according to the present embodiment. If the lower limit of conditional expression (4) is not reached, the surface between the exit surface to the optical element and the surface of the optical member having the optical axis deflection surface that contacts the liquid, or the boundary surface between the first liquid and the second liquid Ghosts are likely to occur between the optical elements and the ghosts and flares generated by the optical elements and optical systems. More preferably, the lower limit value of conditional expression (4) is 0.70, more preferably 0.90.

  In this way, the configuration having the reflecting surface as the optical deflection surface and the reflecting surface being closer to the exit surface side of the optical element than the boundary surface includes the first, second, and third embodiments shown in FIG. Tables 3 and 3 below show the specifications and values corresponding to the conditions in these examples.

(Table 3)
[First embodiment]
d2 = 9.4mm
DL = 5.9mm
(4) d2 / DL = 1.59
[Second Embodiment]
d2 = 9.4mm
DL = 5.9mm
(4) d2 / DL = 1.59
[Third embodiment]
d2 = 11.2mm
DL = 6.2mm
(4) d2 / DL = 1.81
[Fourth embodiment]
d2 = 11.2mm
DL = 6.2mm
(4) d2 / DL = 1.81
[Sixth embodiment]
d2 = 110.2mm
DL = 21.8mm
(4) d2 / DL = 5.06

  Thus, in these examples, all the conditional expressions (4) are satisfied.

  In each embodiment, a configuration in which the deflection member and the liquid container portion are integrated, that is, a configuration in which the liquid container itself is the deflection member may be employed.

  The optical element, finder, photometric optical system, and photographing optical system shown in the present embodiment are configured as described above, and when an imaging method, an observation method, a photometric method, and a photographing method using these optical elements are used, a reflecting member, There is no need to insert it separately from a deflecting member such as a prism, the size of the optical system can be reduced, the number of parts can be reduced, the optical axis alignment with the deflecting member when assembling the optical system is unnecessary, and ghost and flare The occurrence is small, and the influence on the optical aberration due to the variable surface shape error can be reduced.

  In addition, the form of the liquid container in this embodiment is not limited to the Example shown in this specification, if it has the same function. Further, the liquid material (first and second liquids) is not limited to the examples shown in the present specification as long as they have the same function.

It is a sectional side view of the optical element which concerns on 1st Example. It is a top view of the optical element which concerns on 1st Example. It is a sectional side view of the optical element which concerns on 2nd Example. It is a sectional side view of the optical element which concerns on 3rd Example. It is a sectional side view of the optical element which concerns on 4th Example. It is VI-VI sectional drawing of FIG. It is a sectional side view of the finder optical system which concerns on 5th Example. It is a principal part enlarged view of 5th Example. It is a sectional side view of the finder optical system which concerns on 6th Example. It is a sectional side view of the finder optical system which concerns on 7th Example. It is a sectional side view of the finder optical system containing the photometry optical system which concerns on 8th Example. It is a sectional side view of the photometry optical system which concerns on an 8th Example. It is a sectional side view of the photographic optical system concerning the 9th example.

Explanation of symbols

1,1 ', 21,21' Optical element 2,2 ', 22,22' Liquid container (container)
3, 15, 23, 35, 45, 81, 91 Prism members 3a, 15a, 23a, 35a, 55a, 55b, 64a, 64b, 81a, 91a Reflecting surface (optical axis deflecting surface)
7, 27 Second electrode (electrode) 29 Second insulator (insulating means)
7c, 29b Inner wall surface of liquid lens 12, 32 First liquid 13, 33 Second liquid 14, 34 Liquid lens boundary surfaces 40, 50, 60 Viewfinder optical system 53 Focus plate 41 Objective lens section (objective lens group) 43 Field Lens 45a Refractive surface (optical axis deflection surface) 48, 57, 67 Eyepiece unit (eyepiece group)
55, 64 roof prism (prism member) 73 focusing screen 80 photometric optical system 90 photographing optical system X optical axis of liquid lens I incident light beam optical axis O outgoing light beam optical axis

Claims (27)

A first liquid and a second liquid that is not mixed with the first liquid are sealed in a container, and a physical quantity applied to the container is changed, thereby changing a boundary surface between the first liquid and the second liquid. A liquid lens capable of changing the shape, and a deflection member having an optical axis deflection surface;
The optical axis deflection surface is disposed on at least one of an incident light side and an outgoing light side with respect to an optical axis of the liquid lens penetrating a boundary surface between the first liquid and the second liquid. A featured optical element.   The optical element according to claim 1, wherein the optical axis deflection surface is configured in one or more prism members.   The optical element according to claim 2, further comprising an optical member in contact with the first liquid or the second liquid, wherein the optical member and the prism member are bonded.   The optical element according to claim 1, wherein the first liquid has conductivity.   The optical element according to claim 1, wherein the second liquid has an insulating property.   The optical element according to claim 1, wherein the physical quantity is a voltage.   The optical element according to any one of claims 1 to 6, wherein an inner wall surface of the liquid lens is in contact with the boundary surface along an entire circumference around an optical axis of the liquid lens. An electrode provided on a member forming an inner wall surface of the liquid lens;
Having an insulating means provided between the electrode and the first liquid and the second liquid;
The optical element according to claim 7, wherein the interface shape is changed by applying a voltage between the first liquid and the electrode.   The optical element according to claim 1, wherein the first liquid and the second liquid have substantially the same density.   The optical element according to claim 1, wherein the first liquid and the second liquid are configured to have different refractive indexes. Of the optical axis deflection surfaces, at least one surface is a refractive surface,
The angle between the refractive surface and the optical axis of the liquid lens is θ [degree], the length from the refractive surface to the boundary surface on the optical axis of the liquid lens is d, and the boundary surface and the liquid When the maximum diameter of the contact portion with which the inner wall surface of the lens contacts is DL, the following formula
θ <88
d / DL> 0.30
The optical element according to any one of claims 7 to 10, which satisfies: Of the optical axis deflecting surfaces, at least one surface is a reflecting surface, and the reflecting surface is located closer to the incident surface than the boundary surface,
When the length from the incident surface to the boundary surface on the optical axis including the optical axis of the liquid lens is d1, and the maximum diameter of the contact portion where the boundary surface is in contact with the inner wall surface of the liquid lens is DL ,
d1 / DL> 0.50
The optical element according to any one of claims 7 to 10, which satisfies: Of the optical axis deflecting surfaces, at least one surface is a reflecting surface, and the reflecting surface is located closer to the exit surface than the boundary surface,
When the length from the exit surface to the boundary surface on the optical axis including the optical axis of the liquid lens is d2, and the maximum diameter of the contact portion where the boundary surface is in contact with the inner wall surface of the liquid lens is DL ,
d2 / DL> 0.50
The optical element according to any one of claims 7 to 10, which satisfies:   The optical element according to claim 1, wherein an inner wall surface of the liquid lens is formed rotationally symmetrical with respect to an optical axis of the liquid lens.   The optical element according to claim 1, wherein the liquid lens container is the deflecting member. A finder optical system comprising an objective lens group having a positive refractive power and an eyepiece group having a positive refractive power,
A finder optical system configured by arranging the optical element according to claim 1 in at least one optical path of the objective lens group or the eyepiece lens group.   The viewfinder optical system according to claim 16, wherein the optical element is disposed in an optical path of the eyepiece lens group, and is configured to adjust diopter by changing a boundary surface of the liquid lens of the optical element. . A focusing screen provided near the image plane;
A variable focal length element which is the optical element according to any one of claims 1 to 15,
A viewfinder optical system composed of an eyepiece group.   The viewfinder optical system according to claim 18, wherein diopter adjustment is performed by changing a boundary surface of the liquid lens of the optical element.   The viewfinder optical system according to claim 18 or 19, wherein the telecentricity adjustment of the light beam emitted from the optical element is performed by changing a boundary surface of the liquid lens of the optical element.   The finder optical system according to any one of claims 18 to 20, further comprising a field lens. A field lens and a focusing screen provided near the imaging plane;
An image reversal optical system;
The optical element according to any one of claims 1 to 15, wherein a variable focal length element is disposed on a light emission side of the image inverting optical system;
A photometric optical system comprising an optical system having a positive refractive power and disposed on the light exit side of the variable focal length element; An imaging optical system having a positive refractive power as a whole,
A photographing optical system comprising at least one optical element according to any one of claims 1 to 15 in an optical path.   An imaging method for forming an image using the optical element according to claim 1.   An observation method for observing a subject using the finder optical system according to any one of claims 16 to 21.   A photometric method for performing photometry with the photometric optical system according to claim 22.   A photographing method for photographing with the photographing optical system according to claim 23.

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