JP2007121944A - Imaging optical system and observatory optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical system with low electric consumption and little sound, having a short response time, a simple mechanical structure and a small outer diameter, being small in size and capable of focusing. <P>SOLUTION: The optical system includes a rotation symmetrical lens G in which focusing is carried out or visibility adjustment is controlled by use of a deformable mirror DM. The deformable mirror is rendered into a sculptured surface form in at least one state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a variable focus lens, a variable focus diffractive optical element, a variable deflection prism, an optical characteristic variable optical element such as a variable focus mirror, and an optical system including these optical characteristic variable optical elements, for example, a camera, The present invention relates to an optical apparatus such as a digital camera or TV camera finder, an observation optical system such as a telescope, a microscope, or binoculars, glasses, a video projector, a camera, a digital camera, a TV camera, an endoscope, a camera, a digital camera, and a TV camera.

  The conventional lens system uses a lens manufactured by polishing glass or a lens manufactured by molding, and the focal length cannot be changed by the lens itself.

  In order to perform focusing or zooming, it is necessary to move the lens group in the direction of the optical axis, which complicates the mechanical structure. Since a motor or the like is used to move a part of the lens group, there are disadvantages such as high power consumption, noisy sound, long response time, and time to move the lens.

  The present invention has been made in view of such problems of the prior art, and its purpose is to provide observation optics such as a camera, a digital camera, a TV camera, a mobile phone with an imaging function, a telescope, a binocular, and a microscope. System, endoscope, surveillance camera, imaging optical system of small digital camera, etc., low power consumption, quiet sound, short response time, simple mechanical structure and contribute to cost reduction Another object of the present invention is to provide an optical system capable of focusing and zooming despite its small outer diameter and small size.

  In order to achieve the above object, the imaging optical system according to the present invention performs focusing using a variable optical property optical element.

  The imaging optical system according to the present invention performs focusing using a lens and an optical property variable optical element.

  The imaging optical system according to the present invention is preferably configured to be able to focus on an object having a positive object point distance.

  The imaging optical system according to the present invention is preferably configured to be able to focus on an object whose object point distance extends from a positive region to a negative region.

  In addition, the imaging optical system according to the present invention performs diopter adjustment using a variable optical property optical element.

  In addition, the imaging optical system according to the present invention performs diopter adjustment using a lens and an optical property variable optical element.

  The imaging optical system according to the present invention is preferably configured such that the optical characteristic variable optical element has a free-form surface in at least one state.

  The imaging optical system according to the present invention is preferably configured such that the diopter value representing diopter is negative.

  The imaging optical system according to the present invention is preferably configured such that the diopter value representing the diopter continuously changes from positive to negative.

  According to the invention, it is preferable that the optical property variable optical element is a reflective optical property variable optical element or a shape variable mirror.

  According to the present invention, by using a reflective optical property variable optical element or a shape variable mirror, without changing the surface shape of the optical property variable optical element or mirror without driving the lens group back and forth, An observation optical system or the like that can perform focusing or can adjust diopter can be provided.

Hereinafter, embodiments of the present invention will be described based on illustrated examples. Prior to the description, an optical system to which the present invention can be applied and an optical characteristic variable optical element usable in the present invention will be described.
The deformable mirror is one of the deformable mirrors, and is a mirror that can freely change the optical power or aberration by freely changing the surface shape to a convex surface, a flat surface, or a concave surface. As a result, even when the object distance of the imaging system changes, it is possible to focus by simply changing the shape of the variable mirror. At this time, the shape of the variable mirror may be a rotationally symmetric curved surface, but a rotationally asymmetric free curved surface is desirable for better aberration correction.

  The reason will be described in detail below. First, the coordinate system used and the rotationally asymmetric surface will be described. The optical axis defined by the straight line until the axial principal ray intersects the first surface of the optical system is the Z axis, is orthogonal to the Z axis, and is in the decentered plane of each surface constituting the decentered optical system Is defined as the Y axis, and the axis orthogonal to the optical axis and orthogonal to the Y axis is defined as the X axis. The ray tracing direction will be described by tracing the forward ray from the object toward the image plane.

  In general, in a spherical lens system composed only of spherical lenses, spherical aberration generated by the spherical surface, coma aberration, curvature of field, and other aberrations are corrected for each other on several surfaces to reduce the aberration as a whole. It has become.

  On the other hand, a rotationally symmetric aspherical surface or the like is used to satisfactorily correct aberrations with a small number of surfaces. This is to reduce various aberrations that occur on the spherical surface.

  However, in a decentered optical system, it is impossible to correct rotationally asymmetric aberration caused by the decentration with a rotationally symmetric optical system. The rotationally asymmetric aberration generated by this decentration includes distortion, curvature of field, astigmatism generated on the axis, and coma.

  First, rotationally asymmetric field curvature will be described. For example, a light ray incident on a concave mirror decentered from an object point at infinity is reflected and imaged by hitting the concave mirror. It becomes half the radius of curvature of the part hit. Then, as shown in FIG. 41, an image surface inclined with respect to the axial principal ray is formed. Thus, it is impossible to correct rotationally asymmetric field curvature with a rotationally symmetric optical system.

  In order to correct the tilted field curvature with the concave mirror M itself, which is the source of the tilt, the concave mirror M is formed of a rotationally asymmetric surface, and in this example, the curvature is strong (refractive power is increased in the positive direction of the Y axis). If the curvature is weak (refractive power is weak) with respect to the negative Y-axis direction, the correction can be made.

  In addition, the rotationally asymmetric surface preferably has a rotationally asymmetric surface shape that does not have a rotationally symmetric axis both in and out of the surface.

  Next, rotationally asymmetric astigmatism will be described. As in the above description, in the concave mirror M arranged eccentrically, astigmatism as shown in FIG. In order to correct this astigmatism, it is possible to appropriately change the curvature in the X-axis direction and the curvature in the Y-axis direction of the rotationally asymmetric surface as in the above description.

  Further, rotationally asymmetric coma will be described. Similar to the above description, in the concave mirror M arranged eccentrically, coma aberration as shown in FIG. In order to correct this coma, it is possible to change the inclination of the surface as it moves away from the origin of the X axis of the rotationally asymmetric surface and to change the inclination of the surface appropriately depending on whether the Y axis is positive or negative.

  In the decentered optical system of the present invention, it is possible to adopt a configuration in which at least one surface having the reflection action described above is decentered with respect to the axial principal ray and has a rotationally asymmetric surface shape and power. By adopting such a configuration, it becomes possible to correct the decentration aberration generated by giving power to the reflecting surface by the surface itself, and by reducing the power of the refracting surface of the lens, the occurrence of chromatic aberration can be suppressed. Can be small.

  In addition, it is desirable to correct the decentration aberration by making the surface shape of the variable shape mirror and refractive index variable mirror, which are one of the constituent reflecting surfaces of the decentered optical system of the present invention, into a rotationally asymmetric surface.

  The rotationally asymmetric surface used in the present invention is preferably a plane-symmetric free-form surface having only one plane of symmetry. Here, the free-form surface used in the present invention is defined by the following equation. The Z axis of this defining formula is the axis of the free-form surface.

ここで、（ａ）式の第１項は球面項、第２項は自由曲面項である。

Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

In the spherical term,
c: curvature of vertex k: conic constant (conical constant)
r = √ (X ² + Y ² )
N: A natural number of 2 or more.

ただし、Ｃ_j （ｊは２以上の整数）は係数である。 The free-form surface term is

However, C _j (j is an integer of 2 or more) is a coefficient.

  In general, the free-form surface does not have a symmetric surface in both the XZ plane and the YZ plane, but by setting all odd-order terms of X to 0, the plane of symmetry is parallel to the YZ plane. Is a free-form surface with only one. Further, by setting all odd-numbered terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane is obtained.

  Another defining equation for free-form surfaces is the Zernike polynomial given by the following equation (b). The shape of this surface is defined by the following equation. The Z axis of the defining formula becomes the axis of the Zernike polynomial. The definition of the rotationally asymmetric surface is defined by polar coordinates of the height of the Z axis with respect to the XY plane, R is the distance from the Z axis in the XY plane, A is the azimuth around the Z axis, and the X axis It is expressed by the rotation angle measured from.

x = R × cos (A)
y = R × sin (A)
Z = D ₂
+ D ₃ Rcos (A) + D ₄ Rsin (A)
+ D ₅ R ² cos (2A) + D ₆ (R ² −1) + D ₇ R ² sin (2A)
+ D ₈ R ³ cos (3A) + D ₉ (3R ³ −2R) cos (A)
+ D ₁₀ (3R ³ -2R) sin (A) + D ₁₁ R ³ sin (3A)
^{_{+ D 12 R 4 cos (4A}} ) + D 13 (4R 4 -3R 2) cos (2A)
+ D ₁₄ (6R ⁴ -6R ² +1) + D ₁₅ (4R ⁴ -3R ² ) sin (2A)
+ D ₁₆ R ⁴ sin (4A)
+ D ₁₇ R ⁵ cos (5A) + D ₁₈ (5R ⁵ -4R ³ ) cos (3A)
+ D ₁₉ (10R ⁵ -12R ³ + 3R) cos (A)
+ D ₂₀ (10R ⁵ -12R ³ + 3R) sin (A)
+ D ₂₁ (5R ⁵ -4R ³ ) sin (3A) + D ₂₂ R ⁵ sin (5A)
^{_{+ D 23 R 6 cos (6A}} ) + D 24 (6R 6 -5R 4) cos (4A)
+ D ₂₅ (15R ⁶ -20R ⁴ + 6R ² ) cos (2A)
+ D ₂₆ (20R ⁶ -30R ⁴ + 12R ² -1)
+ D ₂₇ (15R ⁶ -20R ⁴ + 6R ² ) sin (2A)
+ D ₂₈ (6R ⁶ -5R ⁴ ) sin (4A) + D ₂₉ R ⁶ sin (6A)
.... (b)
However, _Dm (m is an integer greater than or equal to 2) is a coefficient. In order to design an optical system symmetrical in the X-axis direction, D ₄ , D ₅ , D ₆ , D ₁₀ , D ₁₁ , D ₁₂ , D ₁₃ , D ₁₄ , D ₂₀ , D ₂₁ , D ₂₂ . Use.

The following definition formula (c) can be given as an example of other aspects.
Z = ΣΣC _nm XY
As an example, when k = 7 (seventh order term) is considered, when expanded, it can be expressed by the following expression.
Z = C ₂
+ C ₃ Y + C ₄ | X |
+ C ₅ Y ² + C ₆ Y | X | + C ₇ X ²
+ C ₈ Y ³ + C ₉ Y ² | X | + C ₁₀ YX ² + C ₁₁ | X ³ |
+ C ₁₂ Y ⁴ + C ₁₃ Y ³ | X | + C ₁₄ Y ² X ² + C ₁₅ Y | X ³ | + C ₁₆ X ⁴
+ C ₁₇ Y ⁵ + C ₁₈ Y ⁴ | X | + C ₁₉ Y ³ X ² + C ₂₀ Y ² | X ³ |
+ C ₂₁ YX ⁴ + C ₂₂ | X ⁵ |
+ C ₂₃ Y ⁶ + C ₂₄ Y ⁵ | X | + C ₂₅ Y ⁴ X ² + C ₂₆ Y ³ | X ³ |
+ C ₂₇ Y ² X ⁴ + C ₂₈ Y | X ⁵ | + C ₂₉ X ⁶
+ C ₃₀ Y ⁷ + C ₃₁ Y ⁶ | X | + C ₃₂ Y ⁵ X ² + C ₃₃ Y ⁴ | X ³ |
+ C ₃₄ Y ³ X ⁴ + C ₃₅ Y ² | X ⁵ | + C ₃₆ YX ⁶ + C ₃₇ | X ⁷ |
... (c)

  In the embodiment of the present invention, the surface shape is expressed by a free-form surface using the equation (a). However, similar effects can be obtained by using the equations (b) and (c). Needless to say.

  In the present invention, all of the odd-numbered terms of X in the equation (a) are set to 0, so that a free-form surface having a symmetry plane parallel to the YZ plane is obtained.

  The above definition formula is shown for the purpose of illustrating a rotationally asymmetric curved surface, and it goes without saying that the same effect can be obtained for any other definition formula. If mathematically equivalent, the curved surface shape may be expressed by another definition.

Embodiments of the present invention will be described below with reference to the drawings.
First, a configuration example of a deformable mirror and a variable focus lens applicable to the present invention will be described. FIG. 1 is a schematic configuration diagram of a Kepler finder for a digital camera using a variable optical property mirror, which is an embodiment of the present invention. The configuration of this embodiment can of course be used for a silver salt film camera. First, the optical property variable shape mirror 409 will be described.

  The optical property variable shape mirror 409 is an optical property variable shape mirror (hereinafter simply referred to as a variable shape mirror) composed of an aluminum-coated thin film (reflecting surface) 409a and a plurality of electrodes 409b, and reference numeral 411 denotes each electrode 409b. A plurality of connected variable resistors 412 is a power source connected between the thin film 409a and the electrode 409b via a variable resistor 411 and a power switch 413, and 414 is for controlling the resistance values of the plurality of variable resistors 411. Arithmetic units 415, 416, and 417 are a temperature sensor, a humidity sensor, and a distance sensor respectively connected to the arithmetic unit 414, and these are arranged as shown in the figure to constitute one optical device.

  Note that each surface of the objective lens 902, the eyepiece lens 901, the prism 404, the isosceles right angle prism 405, the mirror 406, and the deformable mirror does not have to be a flat surface. Spherical surface, plane, rotationally symmetric aspherical surface, aspherical surface having a symmetric surface, aspherical surface having only one symmetric surface, aspherical surface without a symmetric surface, free-form surface, non-differentiable point or line The surface may have any shape, such as a surface having any of the above, and may be a surface that can affect the light in any way, whether it is a reflective surface or a refractive surface. Hereinafter, these surfaces are collectively referred to as an extended curved surface.

The thin film 409a is, for example, edited by P. Rai-choudhury, Handbook of Michrolithography, Michromachining and Michrofabrication, Volume 2: Michromachining and Michrofabrication, P495, Fig.8.58, published by SPIE PRESS, Volume 140 (1997) P187. ˜190, when a voltage is applied between the plurality of electrodes 409b, the thin film 409a is deformed by electrostatic force and its surface shape changes, As a result, not only can the focus be adjusted in accordance with the diopter of the observer, but also the lens 901, 902 and / or the prism 404, the isosceles right angle prism 405, the mirror 406 are deformed or the refractive index is changed due to temperature or humidity changes. Or, the lens frame expansion and contraction and deformation, and the degradation of the imaging performance due to assembly errors of parts such as optical elements and frames are suppressed. Correction of aberration caused by the preparative adjustment may be performed.
In addition, what is necessary is just to select the shape of the electrode 409b according to how to deform | transform the thin film 409a, as shown, for example in FIG. 3, FIG.

  According to the present embodiment, the light from the object is refracted by the entrance and exit surfaces of the objective lens 902 and the prism 404, reflected by the deformable mirror 409, transmitted through the prism 404, and isosceles right angle prism 405. (The + mark in the optical path in FIG. 1 indicates that the light beam travels toward the back side of the paper surface), is reflected by the mirror 406, and enters the eye via the eyepiece 901. It has become. As described above, the lenses 901 and 902, the prisms 404 and 405, and the deformable mirror 409 constitute the observation optical system according to the embodiment of the present invention, and the surface shape and thickness of each of these optical elements are optimized. As a result, the aberration of the object surface can be minimized.

  That is, the shape of the thin film 409a as the reflecting surface is controlled by changing the resistance value of each variable resistor 411 by a signal from the arithmetic unit 414 so that the imaging performance is optimized. That is, a signal having a magnitude corresponding to the ambient temperature, humidity, and distance to the object is input from the temperature sensor 415, the humidity sensor 416, and the distance sensor 417 to the arithmetic device 414, and the arithmetic device 414 is based on these input signals. The resistance value of the variable resistor 411 is set so that a voltage that determines the shape of the thin film 409a is applied to the electrode 409b in order to compensate for a decrease in imaging performance due to the ambient temperature and humidity conditions and the distance to the object. Outputs a signal for determination. As described above, since the thin film 409a is deformed by the voltage applied to the electrode 409b, that is, electrostatic force, the shape thereof takes various shapes including an aspherical surface depending on the situation. The distance sensor 417 may not be provided. In that case, the imaging lens 403 of the digital camera is moved so that the high-frequency component of the image signal from the solid-state imaging device 408 becomes substantially maximum, and the object distance is reversed from the position. And the deformable mirror 409 is deformed to focus on the observer's eyes.

  When the deformable mirror 409 is made by lithography, the processing accuracy is good and a good quality is easily obtained, which is preferable.

  In addition, if the thin film 409a is made of a synthetic resin such as polyimide, it is convenient because a large deformation is possible even at a low voltage. In addition, it is convenient in assembly if the prism 404 and the deformable mirror 409 are integrally formed to form a unit.

  In the example of FIG. 1, since the reflecting surface 409a and the deforming electrode 409k are separately provided and integrated with the deforming substrate 409j interposed therebetween, there is an advantage that several manufacturing methods can be selected. In addition, the electrode 409k that is deformed by the reflecting surface 409a may also be used. Since both become one, there is an advantage that the structure is simplified.

  Although not shown, the solid-state imaging device 408 may be integrally formed on the substrate 409j of the deformable mirror 409 by a lithography process.

  The lenses 901 and 902, the prisms 404 and 405, and the mirror 406 can be easily formed with a curved surface having an arbitrary desired shape by forming them with a plastic mold or the like. In the imaging apparatus of the present embodiment, the lenses 901 and 902 are formed away from the prism 404. However, the prisms 404 and 405, the mirrors can be removed so that aberrations can be removed without providing the lenses 901 and 902. If the 406 and the deformable mirror 409 are designed, the prisms 404 and 405 and the deformable mirror 409 become one optical block, which facilitates assembly. Further, some or all of the lenses 901 and 902, the prisms 404 and 405, and the mirror 406 may be made of glass. With such a configuration, an imaging device with higher accuracy can be obtained. The shape of the reflecting surface of the deformable mirror 409 is preferably a free-form surface. This is because aberration correction is easy and advantageous.

  In the example of FIG. 1, the arithmetic device 414, the temperature sensor 415, the humidity sensor 416, and the distance sensor 417 are provided, and the temperature and humidity change, the change of the object distance, etc. are compensated by the deformable mirror 409. It does not have to be. In other words, the arithmetic device 414, the temperature sensor 415, the humidity sensor 416, and the distance sensor 417 may be omitted, and only the observer's diopter change may be corrected by the deformable mirror 409.

FIG. 2 is a schematic configuration diagram showing another embodiment of the deformable mirror 409 according to the present invention.
In the deformable mirror of this embodiment, a piezoelectric element 409c is interposed between a thin film 409a and an electrode 409b, and these are provided on a support base 423. Then, by changing the voltage applied to the piezoelectric element 409c for each electrode 409b, the piezoelectric element 409c can be partially expanded and contracted to change the shape of the thin film 409a. The shape of the electrode 409b may be a concentric division as shown in FIG. 3, a rectangular division as shown in FIG. 4, or any other appropriate shape can be selected. . In FIG. 2, reference numeral 424 denotes a shake sensor connected to the arithmetic device 414. For example, the arithmetic device detects the shake of the digital camera and deforms the thin film 409a so as to compensate for the image disturbance caused by the shake. The voltage applied to the electrode 409b via 414 and the variable resistor 411 is changed. At this time, signals from the temperature sensor 415, the humidity sensor 416, and the distance sensor 417 are simultaneously considered, and focusing, temperature / humidity compensation, and the like are performed. In this case, since stress accompanying deformation of the piezoelectric element 409c is applied to the thin film 409a, it is preferable that the thin film 409a is made thick to some extent and has a corresponding strength.

FIG. 5 is a schematic diagram showing still another embodiment of the deformable mirror 409 according to the present invention.
The deformable mirror of this embodiment is composed of two piezoelectric elements 409c and 409c 'in which a piezoelectric element interposed between a thin film 409a and an electrode 409b is made of a material having piezoelectric characteristics in opposite directions. This is different from the deformable mirror of the embodiment shown in FIG. That is, if the piezoelectric elements 409c and 409c ′ are made of a ferroelectric crystal, they are arranged so that the directions of the crystal axes are opposite to each other. In this case, since the piezoelectric elements 409c and 409c 'expand and contract in the opposite direction when a voltage is applied, the force for deforming the thin film 409a is stronger than in the embodiment shown in FIG. There is an advantage that the shape can be changed greatly.

Examples of materials used for the piezoelectric elements 409c and 409c 'include piezoelectric substances such as barium titanate, Rossiel salt, crystal, tourmaline, potassium dihydrogen phosphate (KDP), ammonium dihydrogen phosphate (ADP), and lithium niobate. There are polycrystals of the same material, crystals of the same material, piezoelectric ceramics of solid solution of PbZrO ₃ and PbTiO ₃ , organic piezoelectric materials such as polyvinyl difluoride (PVDF), ferroelectrics other than the above, etc., especially organic A piezoelectric material is preferable because it has a small Young's modulus and can be deformed greatly even at a low voltage. When these piezoelectric elements are used, it is possible to appropriately deform the shape of the thin film 409a in the above embodiment if the thickness is made non-uniform.

  The material of the piezoelectric elements 409c and 409c ′ includes polyurethane, silicone rubber, acrylic elastomer, PZT, PLZT, polyvinylidene fluoride (PVDF), and other high molecular piezoelectric materials, vinylidene cyanide copolymer, vinylidene fluoride, and triethylene. A copolymer of fluoroethylene or the like is used.

  When an organic material having piezoelectricity, a synthetic resin having piezoelectricity, an elastomer having piezoelectricity, or the like is used, a large deformation of the deformable mirror surface may be realized.

  2 and 6, when an electrostrictive material such as acrylic elastomer or silicon rubber is used, the piezoelectric element 409c is bonded to another substrate 409c-1 and the electrostrictive material 409c-2. It may be a different structure.

FIG. 6 is a schematic diagram showing still another embodiment of the deformable mirror 409 according to the present invention.
In the deformable mirror of this embodiment, the piezoelectric element 409c is sandwiched between the thin film 409a and the electrode 409d, and a voltage is applied between the thin film 409a and the electrode 409d via the drive circuit 425 controlled by the arithmetic unit 414. In addition, separately from this, a voltage is also applied to the electrode 409b provided on the support base 423 via the drive circuit 425 controlled by the arithmetic unit 414. Therefore, in this embodiment, the thin film 409a can be deformed doubly by the voltage applied between the electrode 409d and the electrostatic force generated by the voltage applied to the electrode 409b. Therefore, there are advantages that more deformation patterns are possible and that the responsiveness is fast.

  If the sign of the voltage between the thin film 409a and the electrode 409d is changed, the deformable mirror can be deformed into a convex surface and a concave surface. In that case, a large deformation may be performed by a piezoelectric effect, and a minute shape change may be performed by an electrostatic force. Further, the piezoelectric effect may be mainly used for the deformation of the convex surface, and the electrostatic force may be mainly used for the deformation of the concave surface. Note that the electrode 409d may be composed of a plurality of electrodes like the electrode 409b. This situation is shown in FIG. In the present application, the piezoelectric effect, the electrostrictive effect, and the electrostriction are collectively referred to as the piezoelectric effect. Therefore, an electrostrictive material is also included in the piezoelectric material.

FIG. 7 is a schematic configuration diagram showing still another embodiment of the deformable mirror 409 according to the present invention.
The deformable mirror of the present embodiment can change the shape of the reflecting surface using electromagnetic force. A permanent magnet 426 is provided on the inner bottom surface of the support base 423, and silicon nitride is provided on the top surface. Alternatively, a peripheral portion of a substrate 409e made of polyimide or the like is placed and fixed, and a thin film 409a made of a metal coat such as aluminum is attached to the surface of the substrate 409e to constitute a deformable mirror 409. . A plurality of coils 427 are disposed on the lower surface of the substrate 409e, and these coils 427 are each connected to the arithmetic unit 414 via a drive circuit 428. Accordingly, an appropriate current is supplied from each drive circuit 428 to each coil 427 by an output signal from the arithmetic unit 414 corresponding to a change in the optical system required by the arithmetic unit 414 based on signals from the sensors 415, 416, 417, and 424. Is supplied, each coil 427 is repelled or attracted by an electromagnetic force acting between the permanent magnet 426 and deforms the substrate 409e and the thin film 409a.

  In this case, each coil 427 can flow a different amount of current. Further, the number of the coils 427 may be one, or the permanent magnet 426 may be attached to the substrate 409e and the coil 427 may be provided on the inner bottom surface side of the support base 423. The coil 427 may be made by a technique such as lithography, and the coil 427 may contain an iron core made of a ferromagnetic material.

  In this case, as shown in FIG. 8, the winding density of the thin film coil 427 may be a coil 428 ′ that is changed depending on the location, so that the substrate 409e and the thin film 409a can be given desired deformation. One coil 427 may be provided, and an iron core made of a ferromagnetic material may be inserted into these coils 427.

FIG. 9 is a schematic diagram showing still another embodiment of the deformable mirror 409 according to the present invention.
In the deformable mirror of this embodiment, the substrate 409e is made of a ferromagnetic material such as iron, and the thin film 409a as a reflective film is made of aluminum or the like. In this case, since it is not necessary to provide a thin film coil, the structure is simple and the manufacturing cost can be reduced. If the power switch 413 is replaced with a switching / power switch, the direction of the current flowing in the coil 427 can be changed, and the shapes of the substrate 409e and the thin film 409a can be freely changed.

  FIG. 10 shows the arrangement of the coil 427 in this embodiment, and FIG. 11 shows another arrangement example of the coil 427, but these arrangements can also be applied to the embodiment shown in FIG. FIG. 12 shows an arrangement of permanent magnets 426 that is suitable when the arrangement of the coil 427 is as shown in FIG. 11 in the embodiment shown in FIG. That is, as shown in FIG. 12, if the permanent magnets 426 are arranged radially, a subtle deformation can be given to the substrate 409e and the thin film 409a as compared with the embodiment shown in FIG. Further, in the case where the substrate 409e and the thin film 409a are deformed by using the electromagnetic force as described above (the embodiment shown in FIGS. 7 and 9), there is an advantage that it can be driven at a lower voltage than the case where the electrostatic force is used.

  Although several embodiments of the deformable mirror have been described above, two or more kinds of forces may be used to change the shape of the mirror as shown in the example of FIG. That is, the deformable mirror may be deformed by simultaneously using two or more of electrostatic force, electromagnetic force, piezoelectric effect, magnetostriction, fluid pressure, electric field, magnetic field, temperature change, electromagnetic wave, and the like. That is, if the optical characteristic variable optical element is made by using two or more different driving methods, large deformation and fine deformation can be realized at the same time, and an accurate mirror surface can be realized.

  FIG. 13 shows an imaging system using a deformable mirror 409 applicable to an optical apparatus according to still another embodiment of the present invention, such as a digital camera for a mobile phone, a capsule endoscope, an electronic endoscope, a digital for a personal computer. It is a schematic block diagram of the imaging system used for a camera, a digital camera for PDAs, etc.

  In the imaging system of this embodiment, the deformable mirror 409, the lens 902, the solid-state imaging device 408, and the control system 103 constitute one imaging unit 104. In the imaging unit 104 of this embodiment, the light from the object that has passed through the lens 902 is collected by the deformable mirror 409 and forms an image on the solid-state imaging device 408. The deformable mirror 409 is a kind of optical characteristic variable optical element and is also called a variable focus mirror.

  According to this embodiment, even if the object distance changes, it is possible to focus by deforming the deformable mirror 409, it is not necessary to drive the lens with a motor or the like, and the size, weight, and power consumption are reduced. Excellent in terms of conversion. The imaging unit 104 can be used in all embodiments as an imaging system of the present invention. Also, by using a plurality of deformable mirrors 409, it is possible to make a zoom and variable magnification imaging system and optical system.

  FIG. 13 shows a configuration example of a control system including a transformer booster circuit using coils in the control system 103. In particular, when a laminated piezoelectric transformer is used, the size can be reduced. The booster circuit can be used for the variable shape mirror and variable focus lens using all the electricity of the present invention, but is particularly useful for the variable shape mirror and variable focus lens when using electrostatic force and piezoelectric effect. In order to perform focusing with the deformable mirror 409, for example, the object image is formed on the solid-state image sensor 408 and the high frequency component of the object image is maximized while changing the focal length of the deformable mirror 409. Find it. In order to detect the high-frequency component, for example, a processing apparatus including a microcomputer or the like may be connected to the solid-state imaging device 408, and the high-frequency component may be detected therein.

  FIG. 14 is a schematic configuration diagram of a deformable mirror 188 in which a fluid 161 is taken in and out by a micropump 180 and a mirror surface is deformed according to still another embodiment of the deformable mirror of the present invention. According to this embodiment, there is an advantage that the mirror surface can be greatly deformed. The micropump 180 is a small-sized pump made by, for example, a micromachine technique, and is configured to move with electric power. Examples of pumps made with micromachine technology include those using thermal deformation, those using piezoelectric materials, and those using electrostatic forces.

  FIG. 15 is a schematic configuration diagram showing an embodiment of a micropump applicable to the present invention. In the micropump 180 of the present embodiment, the vibration plate 181 vibrates by an electric force such as an electrostatic force or a piezoelectric effect. FIG. 15 shows an example of vibration due to electrostatic force. In FIG. 15, reference numerals 182 and 183 denote electrodes. A dotted line indicates the diaphragm 181 when it is deformed. With the vibration of the diaphragm 181, the two valves 184 and 185 are opened and closed to send the fluid 161 from the right to the left.

  In the deformable mirror 188 of this embodiment, the reflective film 189 functions as a deformable mirror by being deformed into irregularities according to the amount of the fluid 161. The deformable mirror 188 is driven by the fluid 161. As the fluid, organic substances such as silicon oil, air, water, jelly, and inorganic substances can be used.

  Note that a high voltage may be required for driving in a deformable mirror, a variable focus lens, or the like using electrostatic force or a piezoelectric effect. In this case, for example, as shown in FIG. 13, the control system may be configured using a boosting transformer, a piezoelectric transformer, or the like.

  In addition, if the reflective thin film 409a is also provided in a portion that is not deformed, it can be conveniently used as a reference surface when measuring the shape of the deformable mirror with an interferometer or the like.

  FIG. 16 (FIG. 18) is a diagram showing the basic configuration of the variable focus lens according to the present invention. The variable focus lens 511 includes a first lens 512a having lens surfaces 508a and 508b as first and second surfaces, and a second lens having lens surfaces 509a and 509b as third and fourth surfaces. 512b and a polymer-dispersed liquid crystal layer 514 provided between these lenses via transparent electrodes 513a and 513b, and converges incident light through the first and second lenses 512a and 512b. The transparent electrodes 513a and 513b are connected to an AC power source 516 via a switch 515 so as to selectively apply an AC electric field to the polymer dispersed liquid crystal layer 514. The polymer-dispersed liquid crystal layer 514 includes a large number of minute polymer cells 518 each having an arbitrary shape such as a sphere or a polyhedron each containing liquid crystal molecules 517, and the volume thereof constitutes the polymer cell 518. To the sum of the volume occupied by the polymer and the liquid crystal molecules 517.

Here, when the size of the polymer cell 518 is, for example, spherical, when the average diameter D is λ, and the wavelength of light to be used is, for example,
2nm ≦ D ≦ λ / 5 (1)
And That is, since the size of the liquid crystal molecules 517 is about 2 nm or more, the lower limit value of the average diameter D is 2 nm or more. The upper limit of D also depends on the thickness t of the polymer-dispersed liquid crystal layer 514 in the optical axis direction of the variable focus lens 511, but if it is larger than λ, the refractive index of the polymer and the liquid crystal molecules 517 Due to the difference from the refractive index, light is scattered at the boundary surface of the polymer cell 518 and the polymer-dispersed liquid crystal layer 514 becomes opaque. Therefore, as described later, it is preferably λ / 5 or less. Depending on the optical product in which the variable focus lens is used, high accuracy may not be required, and D may be equal to or less than λ. The transparency of the polymer dispersed liquid crystal layer 514 becomes worse as the thickness t increases.

As the liquid crystal molecules 517, for example, uniaxial nematic liquid crystal molecules are used. The refractive index ellipsoid of the liquid crystal molecules 517 has a shape as shown in FIG.
_{n ox = n oy = n o} ... (2)
It is. However, n _o is the refractive index of an ordinary ray, n _ox and n _oy are refractive indices in directions perpendicular to each other in a plane including an ordinary ray.

  Here, as shown in FIG. 16, when the switch 515 is turned off, that is, when an electric field is not applied to the polymer dispersed liquid crystal layer 514, the liquid crystal molecules 517 are directed in various directions. The layer 514 has a high refractive index and becomes a lens having a strong refractive power. On the other hand, as shown in FIG. 18, when the switch 515 is turned on and an AC electric field is applied to the polymer dispersed liquid crystal layer 514, the major axis direction of the refractive index ellipsoid is the optical axis of the variable focus lens 511. Therefore, the lens has a low refractive index and a low refractive power.

  Note that the voltage applied to the polymer dispersed liquid crystal layer 514 can be changed stepwise or continuously by a variable resistor 519 as shown in FIG. 19, for example. In this way, as the applied voltage increases, the liquid crystal molecules 517 are oriented so that the elliptical long axis gradually becomes parallel to the optical axis of the variable focus lens 511, so that the refractive power is stepwise or continuous. Can be changed to

Here, the average refractive index n _LC ′ of the liquid crystal molecules 517 in the state shown in FIG. 16, that is, in the state where no electric field is applied to the polymer-dispersed liquid crystal layer 514 is the major axis of the refractive index ellipsoid as shown in FIG. When the refractive index in the direction is nz, approximately (n _ox + n _oy + _nz ) / 3≡n _LC ′ (3)
It becomes. Moreover, average refractive index n _LC when equation (2) is satisfied, it represents a n _z the refractive index n _e of the extraordinary ray,
_{(2n o + n e) /} 3≡n LC ... (4)
Given in. At this time, the refractive index nA of the polymer-dispersed liquid crystal layer 514 is the refractive index of the polymer constituting the polymer cell 518, and n _P is the volume ratio of the liquid crystal molecules 517 to the volume of the polymer-dispersed liquid crystal layer 514. ff, Maxwell Garnet's law
n _A = ff · n _LC '+ (1-ff) n _P (5)
Given in.

Accordingly, as shown in FIG. 19, when the curvature radii of the inner surfaces of the lenses 512a and 512b, that is, the surfaces on the polymer dispersed liquid crystal layer 514 side are R ₁ and R ₂ respectively, the focal length f of the variable focus lens 511 ₁ is
1 / f ₁ = (n _A −1) (1 / R ₁ −1 / R ₂ ) (6)
Given in. R ₁ and R ₂ are positive when the center of curvature is on the image point side. Further, refraction by the outer surfaces of the lenses 512a and 512b is excluded. That is, the focal length of the lens by only the polymer dispersed liquid crystal layer 514 is given by the equation (6).

In addition, the average refractive index of ordinary light,
_{(N ox + n oy) /} 2 = n o '... (7)
Then, the refractive index n _B of the polymer-dispersed liquid crystal layer 514 in the state shown in FIG. 18, that is, the state in which an electric field is applied to the polymer-dispersed liquid crystal layer 514, is
_{n B = ff · n o '} + (1-ff) n P ... (8)
In this case, the focal length f _{2 of the} lens formed only by the polymer-dispersed liquid crystal layer 514 is
1 / f ₂ = (n _B −1) (1 / R ₁ −1 / R ₂ ) (9)
Given in. Note that the focal length when a voltage lower than that in FIG. 18 is applied to the polymer dispersed liquid crystal layer 514 is the focal length f ₁ given by equation (6) and the focal length f ₂ given by equation (9). It becomes a value between.

From the above formulas (6) and (9), the change rate of the focal length by the polymer dispersed liquid crystal layer 514 is
| (F ₂ −f ₁ ) / f ₂ | = | (n _B −n _A ) / (n _B −1) | (10)
Given in. Therefore, in order to increase this rate of change, it is sufficient to increase | n _B −n _A |. here,
_{n B -n A = ff (n} o '-n LC') ... (11)
Since it _{is, | n o '-n LC'} | if the large, it is possible to increase the change rate. In practice, n _B is from is about 1.3 to 2,
0.01 ≦ | _no′− n _LC ′ | ≦ 10 (12)
Then, when ff = 0.5, the focal length of the polymer-dispersed liquid crystal layer 514 can be changed by 0.5% or more, so that an effective variable focus lens can be obtained. Note that | n _o '−n _LC ' | cannot exceed 10 due to the limitation of the liquid crystal substance.

Next, the basis of the upper limit value of the above equation (1) will be described. `` Solar Energy Materials and Solar Cells '' Vol. 31, Wilson and Eck, 1993, Eleevier Science Publishers Bv, pp. 197-214, `` Transmission variation using scattering / transparent switching films '' The change in the transmittance τ when the value is changed is shown. Further, in page 206 of FIG. 6 and FIG. 6, r is the radius of the polymer dispersed liquid crystal, t = 300 μm, ff = 0.5, n _P = 1.45, n _LC = 1.585, λ = When 500 nm, the transmittance τ is a theoretical value, and when τ = 5 nm (D = λ / 50, D · t = λ · 6 μm (where D and λ are in nm, and the same applies below)) It is shown that ≈90%, and τ≈50% when r = 25 nm (D = λ / 10).

  Here, for example, assuming that t = 150 μm, assuming that the transmittance τ varies with an exponential function of t, and estimating the transmittance τ when t = 150 μm, r = When 25 nm (D = λ / 10, D · t = λ · 15 μm), τ≈71%. Similarly, when t = 75 μm, τ≈80% when r = 25 nm (D = λ / 10, D · t = λ · 7.5 μm).

From these results,
D ・ t ≦ λ ・ 15μm (13)
Then, τ is 70% to 80% or more, and it is sufficiently practical as a lens. Therefore, for example, when t = 75 μm, sufficient transmittance can be obtained with D ≦ λ / 5.

Further, the transmittance of the polymer dispersed liquid crystal layer 514 becomes better as the value of n _P is closer to the value of n _LC ′. On the other hand, when the n _o 'and n _P are different values, the transmittance of the liquid crystal layer 514 will be degraded. In the state of FIG. 16 and the state of FIG. 18, the transmittance of the polymer dispersed liquid crystal layer 514 is improved on average.
n _P = (n _o '+ n _LC ') / 2 (14)
When you are satisfied.

Here, since the variable focus lens 511 is used as a lens, the transmittance is almost the same in both the state of FIG. 16 and the state of FIG. For this purpose, there are limitations on the polymer material and the liquid crystal molecule 517 constituting the polymer cell 518.
n _o ′ ≦ n _P ≦ n _LC ′ (15)
And it is sufficient.

If the above equation (14) is satisfied, the above equation (13) is further relaxed,
D ・ t ≦ λ ・ 60μm (16)
If it is good. This is because, according to Fresnel's reflection law, the reflectance is proportional to the square of the difference in refractive index, so that light is reflected at the boundary between the polymer constituting the polymer cell 518 and the liquid crystal molecule 517, that is, polymer dispersion. This is because the decrease in the transmittance of the liquid crystal layer 514 is approximately proportional to the square of the difference in refractive index between the polymer and the liquid crystal molecules 517.

The above is the case of n _o ′ = 1.45 and n _LC ′ = 1.585.
D · t ≦ λ · 15 μm · (1.585−1.45) ² / (n _u −n _P ) ² (17)
If it is. However, (n _u −n _P ) ² is the larger of (n _LC ′ −n _P ) ² and (n _o ′ −n _P ) ² .

In order to increase the focal length change of the variable focus lens 511, it is better that the value of ff is large. However, when ff = 1, the polymer volume becomes zero and the polymer cell 518 cannot be formed.
0.1 ≦ ff ≦ 0.999 (18)
And On the other hand, as ff becomes smaller, τ improves, so the above equation (17) is preferably
4 × 10 ^-6 [μm] ^{2 ≦ D · t ≦ λ ·} 45μm · (1.585-1.45) 2 / (n u -n P) 2
… (19)
And As apparent from FIG. 16, the lower limit value of t is t = D, and D is 2 nm or more as described above. Therefore, the lower limit value of D · t is (2 × 10 ⁻³ μm). ² , that is, 4 × 10 ⁻⁶ [μm] ² .

The approximation that expresses the optical properties of materials in terms of refractive index is valid if D is described in “Iwanami Science Library 8 Asteroids Come”, Masai Mukai, 1994, page 58 of Iwanami Shoten. This is the case when it is larger than 10 nm to 5 nm. On the other hand, when D exceeds 500λ, the light scattering becomes geometric, and the light scattering at the interface between the polymer constituting the polymer cell 518 and the liquid crystal molecules 517 increases according to the Fresnel reflection formula. Is practical
7 nm ≦ D ≦ 500λ (20)
And

  FIG. 20 shows a configuration of an imaging optical system for a digital camera using the variable focus lens 511 shown in FIG. In this imaging optical system, an image of an object (not shown) is formed on a solid-state imaging device 523 made of, for example, a CCD via a diaphragm 521, a variable focus lens 511, and a lens 522. In FIG. 20, illustration of liquid crystal molecules is omitted.

  According to such an imaging optical system, the variable focus lens 511 is adjusted by changing the focal length of the variable focus lens 511 by adjusting the AC voltage applied to the polymer dispersed liquid crystal layer 514 of the variable focus lens 511 by the variable resistor 519. For example, it is possible to continuously focus on an object distance from infinity to 600 mm without moving the lens 522 in the optical axis direction.

FIG. 21 is a diagram showing a configuration of an example of a variable focus diffractive optical element according to the present invention.
The variable focus diffractive optical element 531 includes a first transparent substrate 532 having parallel first and second surfaces 532a and 532b, and a ring-shaped diffraction grating having a sawtooth wave cross section having a groove depth in the wavelength order of light. The second transparent substrate 533 having the third surface 533a and the flat fourth surface 533b is formed, and incident light is emitted through the first and second transparent substrates 532 and 533. As described with reference to FIG. 16, a polymer-dispersed liquid crystal layer 514 is provided between the first and second transparent substrates 532 and 533 via the transparent electrodes 513a and 513b, and the switch 515 is connected to the transparent electrodes 513a and 513b. Then, it is connected to an AC power source 516 so that an AC electric field is applied to the polymer dispersed liquid crystal layer 514.

In such a configuration, a light beam incident on the variable focus diffractive optical element 531 has a grating pitch of the third surface 533a as p and m is an integer.
psin θ = mλ (21)
It is deflected by an angle θ that satisfies the condition and emitted. Further, when the groove depth is h, the refractive index of the transparent substrate 533 is n _33, and k is an integer,
h (n _A −n ₃₃ ) = mλ (22)
h (n _B −n ₃₃ ) = kλ (23)
If the above condition is satisfied, the diffraction efficiency becomes 100% at the wavelength λ, and flare can be prevented.

Here, when the difference between both sides of the above equations (22) and (23) is obtained,
h (n _A -n _B ) = (m−k) λ (24)
Is obtained. Therefore, for example, if λ = 500 nm, n _A = 1.55, and n _B = 1.5, then 0.05 h = (m−k) · 500 nm, and m = 1, k = 0, h = 10000 nm. = 10 μm. In this case, the refractive index n ₃₃ of the transparent substrate 533 may be n ₃₃ = 1.5 from the above equation (22). If the grating pitch p at the periphery of the variable focus diffractive optical element 531 is 10 μm, θ≈2.87 °, and a lens with an F number of 10 can be obtained.

  Since the optical path length of the variable focus diffractive optical element 531 changes depending on whether the voltage applied to the polymer-dispersed liquid crystal layer 514 is turned on or off, for example, the variable focus diffractive optical element 531 is arranged in a portion where the light flux of the lens system is not parallel to adjust the focus. Or for changing the focal length of the entire lens system.

In this embodiment, the formulas (22) to (24) are practically
0.7 mλ ≦ h (n _A −n ₃₃ ) ≦ 1.4 mλ (25)
0.7 kλ ≦ h (n _B −n ₃₃ ) ≦ 1.4 kλ (26)
0.7 (m−k) λ ≦ h (n _A −n _B ) ≦ 1.4 (m−k) λ (27)
Should be satisfied.

  There is also a variable focus lens using twisted nematic liquid crystal. FIGS. 22 and 23 show the configuration of the variable focus glasses 550 in this case. The variable focus lens 551 is provided on the inner surfaces of the lenses 552 and 553 and transparent lenses 513a and 513b, respectively. Alignment films 539a and 539b and a twisted nematic liquid crystal layer 554 provided between the alignment films. The transparent electrodes 513a and 513b are connected to an AC power source 516 via a variable resistor 519, and twisted. An AC electric field is applied to the nematic liquid crystal layer 554.

  In such a configuration, when the voltage applied to the twisted nematic liquid crystal layer 554 is increased, the liquid crystal molecules 555 are homeotropically aligned as shown in FIG. 23, and compared with the twisted nematic state where the applied voltage is low as shown in FIG. The refractive index of the twisted nematic liquid crystal layer 554 becomes small and the focal length becomes long.

Here, the helical pitch P of the liquid crystal molecules 555 in the twisted nematic state shown in FIG. 22 needs to be the same or sufficiently smaller than the wavelength λ of light.
2nm ≦ P ≦ 2λ / 3 (28)
And The lower limit of this condition is determined by the size of the liquid crystal molecules, and the upper limit is a value necessary for the twisted nematic liquid crystal layer 554 to act as an isotropic medium in the state of FIG. 22 when the incident light is natural light. If the upper limit condition is not satisfied, the varifocal lens 551 has a different focal length depending on the polarization direction, and thus a double image is formed and only a blurred image can be obtained.

  FIG. 24A shows the configuration of a variable deflection angle prism according to the present invention. The variable deflection prism 561 has a first transparent substrate 562 on the incident side having first and second surfaces 562a and 562b, and a parallel plate shape on the emission side having third and fourth surfaces 563a and 563b. And a second transparent substrate 563. The inner surface (second surface) 562b of the transparent substrate 562 on the incident side is formed in a Fresnel shape, and a transparent electrode is formed between the transparent substrate 562 and the transparent substrate 563 on the outgoing side, as described with reference to FIG. A polymer dispersed liquid crystal layer 514 is provided through 513a and 513b. The transparent electrodes 513a and 513b are connected to an AC power source 516 via a variable resistor 519, thereby applying an AC electric field to the polymer-dispersed liquid crystal layer 514 to control the deflection angle of light transmitted through the variable deflection prism 561. To do. In FIG. 24A, the inner surface 562b of the transparent substrate 562 is formed in a Fresnel shape. For example, as shown in FIG. 24B, the inner surfaces of the transparent substrates 562 and 563 are relatively inclined. It can be formed in a normal prism shape having a surface, or can be formed in the diffraction grating shape shown in FIG. In the case of forming a diffraction grating, the above equations (21) to (27) are similarly applied.

  The variable deflection prism 561 having such a configuration can be effectively used for preventing blurring of, for example, a TV camera, a digital camera, a film camera, and binoculars. In this case, the refractive direction (deflection direction) of the variable deflection prism 561 is preferably the vertical direction, but in order to further improve the performance, the deflection directions of the two variable deflection prisms 561 are made different. For example, as shown in FIG. 25, it is desirable to arrange so that the refraction angle is changed in the vertical and horizontal directions. In FIGS. 24 and 25, liquid crystal molecules are not shown.

  FIG. 26 shows a variable focus mirror using the variable focus lens according to the present invention. The variable focus mirror 565 includes a first transparent substrate 566 having first and second surfaces 566a and 566b, and a second transparent substrate 567 having third and fourth surfaces 567a and 567b. The first transparent substrate 566 is formed in a flat plate shape or a lens shape, and a transparent electrode 513a is provided on the inner surface (second surface) 566b. The second transparent substrate 567 has an inner surface (third surface) 567a. A reflective film 568 is formed on the concave surface, and a transparent electrode 513b is provided on the reflective film 568. As described with reference to FIG. 16, a polymer-dispersed liquid crystal layer 514 is provided between the transparent electrodes 513a and 513b, and these transparent electrodes 513a and 513b are connected to an AC power source 516 via a switch 515 and a variable resistor 519. Then, an AC electric field is applied to the polymer dispersed liquid crystal layer 514. In FIG. 26, liquid crystal molecules are not shown.

  According to such a configuration, light incident from the transparent substrate 566 side serves as an optical path for folding the polymer-dispersed liquid crystal layer 514 by the reflective film 568, so that the function of the polymer-dispersed liquid crystal layer 514 can be given twice. By changing the applied voltage to the polymer dispersed liquid crystal layer 514, the focal position of the reflected light can be changed. In this case, the light incident on the variable focus mirror 565 is transmitted twice through the polymer-dispersed liquid crystal layer 514. Therefore, if t is twice the thickness of the polymer-dispersed liquid crystal layer 514, the above formulas are the same. Can be used. Note that the inner surface of the transparent substrate 566 or 567 can be formed in a diffraction grating pattern as shown in FIG. 21 to reduce the thickness of the polymer dispersed liquid crystal layer 514. In this way, there is an advantage that scattered light can be reduced.

  In the above description, in order to prevent the deterioration of the liquid crystal, an AC electric field is applied to the liquid crystal using the AC power source 516 as a power source. However, a DC electric field is applied to the liquid crystal using a DC power source. You can also As a method of changing the direction of the liquid crystal molecules, in addition to changing the voltage, the frequency of the electric field applied to the liquid crystal, the strength / frequency of the magnetic field applied to the liquid crystal, or the temperature of the liquid crystal may be changed. In the embodiment described above, the polymer-dispersed liquid crystal may be close to solid rather than liquid. In that case, one of the lenses 512a and 512b, one of the transparent substrate 532, the lens 538, and one of the lenses 552 and 553, FIG. The transparent substrate 563 in (a), one of the transparent substrates 562 and 563 in FIG. 24B, and one of the transparent substrates 566 and 567 may be omitted.

  As described above, the merit of the optical element of the type in which the focal length of the optical element is changed by changing the refractive index of the medium as described in FIGS. 16 to 26 is that the mechanical design is easy because the shape does not change. There is a simple mechanical structure, etc.

FIG. 27 is a schematic configuration diagram of an imaging unit 141 using a variable focus lens 140 according to still another embodiment of the optical apparatus of the present invention. The imaging unit 141 can be used as an imaging system of the present invention.
In the present embodiment, the lens 102 and the variable focus lens 140 constitute an imaging lens. The imaging lens 141 and the solid-state imaging device 408 constitute an imaging unit 141. The variable focus lens 140 is configured by sandwiching a fluid or jelly-like substance 144 that transmits light between a transparent member 142 and a soft transparent substance 143 such as a piezoelectric synthetic resin.

  As the fluid or jelly-like substance 144, silicon oil, elastic rubber, jelly, water, or the like can be used. Transparent electrodes 145 are provided on both surfaces of the transparent material 143. When a voltage is applied via the circuit 103, the transparent material 143 is deformed by the piezoelectric effect of the transparent material 143, and the focal length of the variable focus lens 140 is changed. It is like that.

  Therefore, according to the present embodiment, even when the object distance is changed, focusing can be performed without moving the optical system with a motor or the like, which is excellent in terms of small size, light weight, and low power consumption.

  In FIG. 27, 145 is a transparent electrode, and 146 is a cylinder for accumulating fluid. The material of the transparent material 143 includes polyurethane, silicone rubber, acrylic elastomer, PZT, PLZT, polyvinylidene fluoride (PVDF) and other high molecular piezoelectric materials, vinylidene cyanide copolymer, vinylidene fluoride and trifluoroethylene. A copolymer or the like is used.

  When an organic material having piezoelectricity, a synthetic resin having piezoelectricity, an elastomer having piezoelectricity, or the like is used, a large deformation of the varifocal lens surface may be realized. A transparent piezoelectric material may be used for the variable focus lens.

  In the example of FIG. 27, the varifocal lens 140 may have a structure in which the support member 147 is provided and the cylinder 146 is omitted, as shown in FIG. 28, instead of the cylinder 146. The support member 147 fixes a portion of the periphery of the transparent substance 143 with the transparent electrode 145 interposed therebetween. According to this embodiment, by applying a voltage to the transparent material 143, even when the transparent material 143 is deformed, as shown in FIG. 146 becomes unnecessary. 28 and 29, reference numeral 148 denotes a deformable member, which is made of an elastic body, an accordion-like synthetic resin, a metal, or the like.

  In the embodiments shown in FIGS. 27 and 28, the transparent material 143 is deformed in the reverse direction when a voltage is applied in the reverse direction, so that a concave lens can be formed.

  Note that in the case where an electrostrictive material such as acrylic elastomer or silicon rubber is used for the transparent substance 143, the transparent substance 143 may have a structure in which a transparent substrate and an electrostrictive material are bonded to each other.

  FIG. 30 is a schematic configuration diagram of a variable focus lens 167 according to still another embodiment of the variable focus lens of the present invention, in which the fluid 161 is taken in and out by the micropump 160 to deform the lens surface. The micropump 160 is, for example, a small-sized pump made by a micromachine technique and is configured to move with electric power. The fluid 161 is sandwiched between the transparent substrate 163 and the elastic body 164. In FIG. 30, reference numeral 165 denotes a transparent substrate for protecting the elastic body 164, and it is not necessary to provide it.

  Examples of pumps made with micromachine technology include those using thermal deformation, those using piezoelectric materials, and those using electrostatic forces.

  Then, two micropumps 180 as shown in FIG. 15 may be used, for example, like the micropump 160 used in the variable focus lens shown in FIG.

  In a variable focus lens using an electrostatic force or a piezoelectric effect, a high voltage may be required for driving. In that case, the control system may be configured by using a step-up transformer or a piezoelectric transformer. In particular, when a laminated piezoelectric transformer is used, the size may be reduced.

  FIG. 31 is a schematic configuration diagram of a variable focus lens 201 using a piezoelectric material 200 as another embodiment of the optical characteristic variable optical element according to the present invention. A material similar to the transparent material 143 is used for the piezoelectric material 200, and the piezoelectric material 200 is provided on a transparent and soft substrate 202. Note that a synthetic resin or an organic material is preferably used for the substrate 202.

  In the present embodiment, the piezoelectric material 200 is deformed by applying a voltage to the piezoelectric material 200 via the two transparent electrodes 59, and has a function as a convex lens in FIG.

  In addition, the shape of the substrate 202 is formed in a convex shape in advance, and the size of at least one of the two transparent electrodes 59 is different from that of the substrate 202. For example, one transparent electrode 59 is If it is made smaller than the substrate 202, when the voltage is turned off, as shown in FIG. 32, only a predetermined portion where the two transparent electrodes 59 are opposed to each other is deformed into a concave shape and has a function of a concave lens. Operates as a variable focus lens. At this time, since the substrate 202 is deformed so that the volume of the fluid 161 does not change, there is an advantage that a liquid reservoir becomes unnecessary.

  In this embodiment, there is a great merit in that a part of the substrate holding the fluid 161 is deformed by a piezoelectric material and a liquid reservoir is not required.

  As can be said for the embodiment of FIG. 30, the transparent substrates 163 and 165 may be configured as a lens or a plane.

  FIG. 33 shows still another embodiment of the optical characteristic variable optical element according to the present invention, and is a schematic configuration diagram of a variable focus lens using two thin plates 200A and 200B made of a piezoelectric material.

  The variable focus lens of the present embodiment has an advantage that the amount of deformation is increased and a large variable focus range can be obtained by reversing the directionality of the materials of the thin plates 200A and 200B.

  In FIG. 33, reference numeral 204 denotes a lens-shaped transparent substrate.

  Also in this embodiment, the transparent electrode 59 on the right side of the drawing is formed smaller than the substrate 202.

  In the embodiment shown in FIGS. 31 to 33, the thickness of the substrate 202 and the thin plates 200, 200A, and 200B may be made non-uniform so as to control the deformation when a voltage is applied. By doing so, it is possible to correct aberrations of the lens, which is convenient.

  FIG. 34 is a schematic diagram showing still another embodiment of the variable focus lens according to the present invention. The variable focus lens 207 of the present embodiment is configured using an electrostrictive material 206 such as silicon rubber or acrylic elastomer.

  According to the configuration of the present embodiment, when the voltage is low, it acts as a convex lens as shown in FIG. 34, and when the voltage is increased, as shown in FIG. The focal length increases. Therefore, it operates as a variable focus lens.

  According to the variable focus lens of this embodiment, there is an advantage that power consumption is small because a large power source is not required.

  What can be said in common with the variable focus lens of FIGS. 27 to 35 described above is that the variable focus is realized by changing the shape of the medium acting as the lens. Compared to a variable focus lens that changes the refractive index, there are merits such that the range of change in focal length can be freely selected and the size can be freely selected.

FIG. 36 is a schematic configuration diagram of a variable focus lens using a photomechanical effect, which is still another embodiment of the optical characteristic variable optical element according to the present invention. In the variable focus lens 214 of this embodiment, the azobenzene 210 is sandwiched between transparent elastic bodies 208 and 209, and the azobenzene 210 is irradiated with light via a transparent spacer 211. In FIG. 36, reference numerals 212 and 213 denote light sources such as LEDs and semiconductor lasers having center wavelengths λ ₁ and λ ₂ , respectively.

In this embodiment, when light having a center wavelength of λ ₁ is irradiated onto the trans-type azobenzene shown in FIG. 37A, the azobenzene 210 changes to the cis-type shown in FIG. To do. For this reason, the shape of the variable focus lens 214 becomes light, and the convex lens action is reduced. On the other hand, when the cis-type azobenzene 210 is irradiated with light having a center wavelength of λ ₂ , the azobenzene 210 changes from the cis-type to the trans-type, and the volume increases. For this reason, the shape of the variable focus lens 214 becomes thick, and the convex lens action increases. In this way, the optical element 214 of this embodiment functions as a variable focus lens.

  In the variable focus lens 214, light is totally reflected at the boundary surfaces of the transparent elastic bodies 208 and 209 with the air, so that light does not leak to the outside and efficiency is high. The wavelength of light used as a lens is not limited to visible light, but may be infrared light or the like. As the azobenzene 210, a mixture of azobenzene and another liquid may be used.

  FIG. 38 is a schematic diagram showing still another embodiment of the deformable mirror according to the present invention. In this embodiment, the description will be made assuming that the digital camera is used. In the figure, 411 is a variable resistor, 414 is an arithmetic unit, 415 is a temperature sensor, 416 is a humidity sensor, 417 is a distance sensor, and 424 is a shake sensor.

  The deformable mirror 45 of this embodiment is provided with a divided electrode 409b spaced apart from an electrostrictive material 453 made of an organic material such as acrylic elastomer, and an electrode 452 and a deformable substrate 451 are arranged on the electrostrictive material 453 in this order. Further, a reflection film 450 made of a metal such as aluminum that reflects incident light is provided thereon.

  With this configuration, there is an advantage that the surface shape of the reflective film 450 becomes smoother and optical aberrations are less likely to occur compared to the case where the divided electrode 409b is integrated with the electrostrictive material 453.

  Note that the disposition of the deformable substrate 451 and the electrode 452 may be reversed.

  In FIG. 38, reference numeral 449 denotes a button for zooming or zooming the optical system, and the deformable mirror 45 deforms the shape of the reflective film 450 by pressing the button 449 by the user, Control is performed via an arithmetic unit 414 so that zooming can be performed.

  Note that a piezoelectric material such as barium titanate described above may be used instead of the electrostrictive material made of an organic material such as acrylic elastomer.

  In addition, it can be said that it is common to the deformable mirror of the present application, but the shape when the deformed portion of the reflecting surface is viewed from the direction perpendicular to the reflecting surface is a shape that is long in the direction of the incident surface of the axial ray, for example, It should be oval, oval, polygonal, etc. This is because the deformable mirror is often used at an oblique incidence as in the example of FIG. 13, but in order to suppress the aberration that occurs at this time, the shape of the reflecting surface can be a spheroid, a paraboloid, a rotational biplane. The shape close to the curved surface is good, and in order to deform the deformable mirror like that, the shape when the deformed part of the reflecting surface is viewed from the direction perpendicular to the reflecting surface is the direction of the incident surface of the axial ray. This is because it is better to have a long shape.

Examples of the present invention will be described below. The configuration parameters of each embodiment will be described later.
In each embodiment, the Z axis of the coordinate system on the object plane is defined by a straight line that passes through the center of the object and is perpendicular to the object plane. A direction perpendicular to the Z axis is defined as a Y axis, and an axis constituting the Y axis, the Z axis, and a right-handed orthogonal coordinate system is defined as an X axis.

  In the following embodiments, each surface is decentered in this YZ plane, and the only symmetric surface of each rotationally asymmetric free-form surface is the YZ plane. The origin of the coordinate system when performing eccentricity is the point moved by the surface interval in the Z-axis direction from the surface top position of the k-1 plane when the surface to be eccentric is the k plane. The eccentric surface has a shift distance (X-axis direction, Y-axis direction, and Z-axis direction are X, Y, and Z, respectively) from the origin of the coordinates, and the X-axis, Y-axis, It is given by tilt angles (α, β, γ, and units are degrees, respectively) with the Z axis as the rotation axis. However, regarding the sign of the tilt angle, when viewed from the positive direction of each rotation axis, α and β are clockwise when the tilt angle is positive, and γ is counterclockwise when the tilt angle is positive. The order of eccentricity is X shift, Y shift, Z shift, α tilt, β tilt, and γ tilt.

  In the following embodiments, the eccentricity is performed by decenter and bend. That is, when the k plane is decentered, the surface top position of the (k + 1) plane is a point moved from the surface top position of the k surface after the eccentricity by the surface interval in the Z-axis direction.

  In addition, the coordinate system of the optical system after the light beam is reflected by the reflecting surface is defined as the coordinate system before reflection is rotated by 2α when the rotation angle of the reflecting surface is α, The surface spacing is negative. As a result, the light beam travels along the negative Z-axis direction of the optical system.

  Examples 1 and 2 below relate to an imaging optical system and an observation optical system, but can be applied to various applications. Specific applications of the imaging optical system include film cameras, digital cameras, robot eyes, interchangeable lens digital SLR cameras, TV cameras, video recording devices, electronic video recording devices, camcorders, VTR cameras, electronic endoscopes, etc. There is. Specific examples of the observation optical system include a microscope, a telescope, glasses, binoculars, a loupe, a fiberscope, a viewfinder, and a viewfinder. Even when the observer has astigmatism, it is possible to correct astigmatism and observe a good image. Further, when used in a magnifying glass of an observation apparatus, it is possible to correct a change in diopter caused by a change in an object distance to be photographed.

  Example 1 is an observation optical system that performs diopter adjustment using a deformable mirror, as shown in an optical path diagram including an axial principal ray in FIG. Here, the relationship between the operations when imaging and diopter adjustment will be described with reference to FIG.

  In FIG. 44, the light path from the aperture stop ST to the image group I via the lens group G and the shape variable mirror DM is referred to as a reverse light path, and conversely, the light beam passes from the image surface I to the shape variable mirror DM and the lens group G. The optical path that reaches the aperture stop ST will be referred to as a forward optical path.

  A group of rays incident on the stop ST in the reverse optical path is defined by an object point distance, and is shaped so as to form an incident ray group corresponding to the object point distance within a predetermined range including positive and negative values on the image plane I. Controls the shape of the variable mirror DM. The function of this embodiment in this situation corresponds to imaging.

  On the other hand, in the case of the forward light path, a group of light beams that are imaged on the image plane I are reflected by the shape variable mirror DM and then imaged again on the object plane O via the stop ST. Here, by bringing a human eye to the position of the stop ST, an enlarged image on the image plane I can be observed. In a general zoom finder configuration, an intermediate image is formed on the image plane I by the objective optical system, and this intermediate image is propagated to the human retina through the forward light path. Although not shown in FIG. 39, there are refracting surfaces such as a cornea surface and a crystalline lens between the stop ST and the human retina in the forward light path, and the image quality of the observation image is determined through lens action of these refracting surfaces. .

  However, since there are individual differences in the shape of the corneal surface and the lens adjustment function, it is preferable that the object point distance, that is, the diopter can be changed by the shape adjustment function of the shape variable mirror. In this embodiment, therefore, the shape of the deformable mirror is adjusted, and the observation optical system is designed so that good observation images can be obtained for four diopters from diopter 1 to diopter 4. It was. Here, diopters 1, 2, 3, and 4 are −4D, −2D, −1D, and + 1D (D represents diopter), respectively, and an object point that is represented by a surface interval from the object plane O to the aperture stop ST. In terms of distance, they are −250 mm, −500 mm, −1000 mm, and +1000 mm, respectively. However, the object point distance is defined as taking a negative sign when the line segment from the object plane O to the stop ST in the reverse optical path is leftward and taking a positive sign when it is rightward.

  In the case where imaging is performed using the deformable mirror and the case where diopter adjustment is performed, the traveling direction of the light group in FIG. 39 is different, but ray tracing is performed between planes conjugate to each other such as the object plane O and the image plane I. When performing, parameters such as aberration and MTF representing imaging performance are almost the same in both the forward and reverse optical paths. Therefore, in this embodiment, the MTF in the case of the reverse optical path is used to evaluate the imaging performance of the observation optical system.

  The purpose of the present embodiment is to design the optimum shape of the deformable mirror DM for each of the four diopters, and the parameters other than the object point distance and the deformable mirror DM are the same values as shown below. did. A variable shape mirror with a maximum image height of 3.860 mm (maximum image height in the X-axis direction: 2.316 mm, maximum image height in the Y-axis direction: 3.088 mm) on the image plane I, a diaphragm diameter of 5.00 mm, and a diopter of 1. The shape of DM was a plane, and the incident angle of the paraxial principal ray at this time was 45 °. At diopters 2, 3 and 4, the shape of the deformable mirror DM is basically a free-form surface, and therefore the incident angle of the axial principal ray slightly changes from 45 ° due to the contribution from the odd-order terms of Y.

  Next, the constituent parameters of Examples 1 and 2 will be shown. The free-form surface used in the present invention is defined by the above-described equation (a). The Z axis of the defining formula becomes the axis of the free-form surface.

An aspherical surface is a rotationally symmetric aspherical surface given by the following definition.
^{Z = (Y 2 / R)} / [1+ {1- (1 + K) Y 2 / R 2} 1/2]
+ AY ⁴ + BY ⁶ + CY ⁸ + DY ¹⁰ + ……
... (d)
However, Z is a straight line passing through the center of the object and perpendicular to the object surface, and Y is in a direction perpendicular to Z. Here, R is a paraxial radius of curvature, K is a conic constant, A, B, C, D,... Are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively. The Z axis of this defining formula is the axis of a rotationally symmetric aspherical surface.

The configuration parameters of Example 1 are shown below. In the table below, “FFS” indicates a free-form surface. Note that terms relating to free-form surfaces, aspheric surfaces, etc., for which no data is described, are zero. The refractive index is shown for d-line (wavelength 587.56 nm). The unit of length is mm. In the data, for example, 4.0399e-005 means 4.0399 × 10 ⁻⁵ .

[Diopter 1: -4D]

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ -250.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 2.6465 1.4957 69.5
3 -11.1874 3.3535 1.6044 38.4
4 Aspherical surface [2] 6.0000
5 FFS [1] -16.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Curvature radius 15.8922
k 0.0000e + 000
a 4.0399e-005 b 8.5655e-006 c -2.8943e-007
d 4.0562e-009

Aspherical [2]
Radius of curvature -44.0279
k 0.0000e + 000
a 2.4061e-005 b 9.0354e-006 c -2.6204e-007
d 3.2911e-009

FFS [1]
Radius of curvature ∞

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 45.0000 β 0.0000 γ 0.0000

[Diopter 2: -2D]

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ -500.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 2.6465 1.4957 69.5
3 -11.1874 3.3535 1.6044 38.4
4 Aspherical surface [2] 6.0000
5 FFS [1] -16.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Curvature radius 15.8922
k 0.0000e + 000
a 4.0399e-005 b 8.5655e-006 c -2.8943e-007
d 4.0562e-009

Aspherical [2]
Radius of curvature -44.0279
k 0.0000e + 000
a 2.4061e-005 b 9.0354e-006 c -2.6204e-007
d 3.2911e-009

FFS [1]
Radius of curvature ∞
C4 -1.5683e-003 C6 -7.7971e-004 C8 4.6707e-005
C10 2.0270e-005 C11 1.4426e-005 C13 4.2636e-006
C15 1.9631e-006 C17 1.0900e-006 C19 -1.2983e-006
C21 1.9465e-007 C22 -5.0935e-007 C24 -4.5578e-007
C26 -1.3716e-007 C28 -5.4330e-008

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 45.0000 β 0.0000 γ 0.0000

[Diopter 3: -1D]

Surface number Curvature radius Surface spacing Eccentric Refractive index Abbe number Object surface ∞ -1000.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 2.6465 1.4957 69.5
3 -11.1874 3.3535 1.6044 38.4
4 Aspherical surface [2] 6.0000
5 FFS [1] -16.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Curvature radius 15.8922
k 0.0000e + 000
a 4.0399e-005 b 8.5655e-006 c -2.8943e-007
d 4.0562e-009

Aspherical [2]
Radius of curvature -44.0279
k 0.0000e + 000
a 2.4061e-005 b 9.0354e-006 c -2.6204e-007
d 3.2911e-009

FFS [1]
Radius of curvature ∞
C4 -2.4007e-003 C6 -1.1450e-003 C8 7.5546e-005
C10 3.7600e-005 C11 1.5134e-005 C13 1.2730e-006
C15 9.6704e-007 C17 8.3269e-007 C19 -1.2385e-006
C21 -2.5462e-009 C22 -5.3037e-007 C24 -2.8803e-007
C26 -1.3508e-007 C28 -4.2862e-008

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 45.0000 β 0.0000 γ 0.0000

[Diopter 4: + 1D]

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ 1000.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 2.6465 1.4957 69.5
3 -11.1874 3.3535 1.6044 38.4
4 Aspherical surface [2] 6.0000
5 FFS [1] -16.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Curvature radius 15.8922
k 0.0000e + 000
a 4.0399e-005 b 8.5655e-006 c -2.8943e-007
d 4.0562e-009

Aspherical [2]
Radius of curvature -44.0279
k 0.0000e + 000
a 2.4061e-005 b 9.0354e-006 c -2.6204e-007
d 3.2911e-009

FFS [1]
Radius of curvature ∞
C4 -3.8395e-003 C6 -1.8094e-003 C8 1.2748e-004
C10 6.4026e-005 C11 1.6074e-005 C13 -9.3559e-006
C15 -1.0120e-007 C17 1.6437e-006 C19 -2.7487e-006
C21 8.4396e-008 C22 -5.4634e-007 C24 -2.0311e-007
C26 2.6676e-007 C28 -9.3455e-008

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 45.0000 β 0.0000 γ 0.0000

  Example 2 is an imaging optical system using a deformable mirror as shown in FIG. At a diopter of 1, the incident angle of the axial principal ray on the deformable mirror DM is 25 °, and the design of the lens group G is also a preferred shape according to the incident angle. The diopter setting value, aperture diameter, image height, and evaluation wavelength were the same as those in Example 1.

  In a decentered optical system, generally, the greater the angle of incidence on a decentered surface with curvature, the greater the amount of aberration that occurs on the decentered surface. Also in the embodiment according to the present invention, the MTF characteristic in which the incident angle to the eccentric surface is 25 ° is better than the design of the first embodiment in which the incident angle to the eccentric surface is 45 °. Indicated. However, if the incident angle on the decentered surface is smaller than 25 °, the reflected light group mechanically interferes with optical components such as the lens G, resulting in unnecessary stray light or deterioration in imaging performance. It is not preferable.

The configuration parameters of the second embodiment are shown below. In the table below, “FFS” indicates a free-form surface. Note that terms relating to free-form surfaces, aspheric surfaces, etc., for which no data is described, are zero. The refractive index is shown for d-line (wavelength 587.56 nm). The unit of length is mm. In the data, for example, −7.96585e-005 means −7.9985 × 10 ⁻⁵ .

[Diopter 1: -4D]

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ -250.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 3.2248 1.5098 68.1
3 -7.4027 2.7752 1.6262 35.7
4 Aspherical surface [2] 10.0000
5 FFS [1] -12.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Radius of curvature 37.6065
k 0.0000e + 000
a -7.9685e-005 b 6.6052e-006 c -3.6249e-007
d 6.8395e-009

Aspherical [2]
Radius of curvature -15.4059
k 0.0000e + 000
a -7.8413e-005 b 5.3255e-006 c -2.2088e-007
d 3.0818e-009

FFS [1]
Radius of curvature ∞

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 25.0000 β 0.0000 γ 0.0000

[Diopter 2: -2D]

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ -500.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 3.2248 1.5098 68.1
3 -7.4027 2.7752 1.6262 35.7
4 Aspherical surface [2] 10.0000
5 FFS [1] -12.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Radius of curvature 37.6065
k 0.0000e + 000
a -7.9685e-005 b 6.6052e-006 c -3.6249e-007
d 6.8395e-009

Aspherical [2]
Radius of curvature -15.4059
k 0.0000e + 000
a -7.8413e-005 b 5.3255e-006 c -2.2088e-007
d 3.0818e-009

FFS [1]
Radius of curvature ∞
C4 -1.8380e-003 C6 -1.4650e-003 C8 5.2173e-005
C10 4.0020e-005 C11 1.1427e-006 C13 -6.0540e-006
C15 -1.4391e-006 C17 3.5338e-007 C19 -1.8183e-006
C21 1.5986e-007 C22 3.9744e-008 C24 2.6963e-007
C26 2.1113e-007 C28 1.0422e-007

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 25.0000 β 0.0000 γ 0.0000

[Diopter 3: -1D]

Surface number Curvature radius Surface spacing Eccentric Refractive index Abbe number Object surface ∞ -1000.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 3.2248 1.5098 68.1
3 -7.4027 2.7752 1.6262 35.7
4 Aspherical surface [2] 10.0000
5 FFS [1] -12.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Radius of curvature 37.6065
k 0.0000e + 000
a -7.9685e-005 b 6.6052e-006 c -3.6249e-007
d 6.8395e-009

Aspherical [2]
Radius of curvature -15.4059
k 0.0000e + 000
a -7.8413e-005 b 5.3255e-006 c -2.2088e-007
d 3.0818e-009

FFS [1]
Radius of curvature ∞
C4 -2.7058e-003 C6 -2.1693e-003 C8 6.4411e-005
C10 5.5062e-005 C11 -1.4466e-007 C13 -4.6813e-006
C15 -2.9083e-006 C17 5.2926e-007 C19 -1.7679e-006
C21 1.4804e-007 C22 7.5115e-008 C24 2.0391e-007
C26 1.6700e-007 C28 1.3092e-007

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 25.0000 β 0.0000 γ 0.0000

[Diopter 4: + 1D]

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ 1000.0000
Diaphragm surface ∞ 17.0000
2 Aspherical surface [1] 3.2248 1.5098 68.1
3 -7.4027 2.7752 1.6262 35.7
4 Aspherical surface [2] 10.0000
5 FFS [1] -12.9000 Eccentricity (1)
Image plane ∞ 0.0000

Aspherical [1]
Radius of curvature 37.6065
k 0.0000e + 000
a -7.9685e-005 b 6.6052e-006 c -3.6249e-007
d 6.8395e-009

Aspherical [2]
Radius of curvature -15.4059
k 0.0000e + 000
a -7.8413e-005 b 5.3255e-006 c -2.2088e-007
d 3.0818e-009

FFS [1]
Radius of curvature ∞
C4 -4.3500e-003 C6 -3.4888e-003 C8 1.2411e-004
C10 7.8783e-005 C11 2.4296e-006 C13 1.5983e-006
C15 1.5650e-006 C17 1.9974e-007 C19 -2.4199e-006
C21 6.1783e-007 C22 3.7634e-008 C24 -7.7169e-008
C26 3.4108e-008 C28 -5.2002e-008

Eccentric [1]
X 0.0000 Y 0.0000 Z 0.0000
α 25.0000 β 0.0000 γ 0.0000

  The imaging optical system or the observation optical system according to the present invention can provide a compact and high-performance imaging optical system capable of focusing or an observation optical system capable of adjusting diopter when one or more of the following conditional expressions are satisfied. It ’s still good.

When the incident angle of the axial chief ray (hereinafter referred to as chief ray) to the deformable mirror DM is θ,
5 ° < θ < 70 ° (29)
It is desirable to satisfy.

  By satisfying Expression (29), the decentration aberration of the light beam reflected by the deformable mirror DM can be suppressed.

Furthermore, in a state with the deformable mirror DM,
10 ° < θ < 60 ° (30)
If it satisfies, good performance can be realized as a practical product, so it is even better.

Furthermore, in a state with the deformable mirror DM,
20 ° < θ < 50 ° (31)
If the above is satisfied, good performance can be realized as a product that can be used for various purposes.

Further, in the optical system including the lens G and the deformable mirror DM, when the rear focal length when the reflecting surface shape of the deformable mirror is a plane is f,
_{0 <| C 4 f | <} 1 and _{0 <| C 6 f | <} 1 ... (32)
It is desirable to satisfy.

  By satisfying Expression (32), the deformation amount of the deformable mirror DM can be suppressed within an appropriate range, so that the manufacturing cost of the deformable mirror device can be suppressed.

Furthermore, in a state with the deformable mirror DM,
_{0 <| C 4 f | <} 0.25 and _{0 <| C 6 f | <} 0.25 ... (33)
If this condition is satisfied, the decentration aberration of the light beam reflected by the variable shape mirror can be reduced.

Further, in a state where the deformable mirror DM is present,
0.1 < | C ₄ / C ₆ | cos ² θ < 10 (34)
It is desirable to satisfy.

  By satisfying Expression (34), the paraxial ray on the axis in the x-axis direction (hereinafter, paraxial ray) and the paraxial ray in the y-axis direction intersect with the axial principal ray at substantially the same point, and the image plane Astigmatism in I can be suppressed to an appropriate range. The reason will be described with reference to FIG.

FIG. 45A shows a state where the paraxial light beam RP is reflected by the variable shape mirror DM when the incident angle θ of the principal ray RC incident on the variable shape mirror DM is 0 °. The principal ray RC overlaps the z axis before and after reflection. When the incident angle is 0 °, the optical system is a rotation target around the z-axis, so the x-axis direction and the y-axis direction are not distinguished. Therefore, the x axis and the y axis are collectively shown as the r axis. The free-form surface representing the shape of the reflecting surface of the deformable mirror DM has only a second-order coefficient C. Therefore, the cross section of the reflecting surface of the deformable mirror by the rz plane is a parabola represented by z = Cr ² . 45A, 45B and 45C, the principal ray RC and the paraxial ray RP incident on the deformable mirror DM are parallel to each other, and the distance between both rays is d.

となる。 If the incident angle of the paraxial ray RP to the deformable mirror DM is δ, tan δ is equal to the inclination of the parabola at the incident point A.
tanδ = 2Cd (35)
Holds. If the distance from the incident point A to the focused point F after reflection is f _R (d), the focal length f _R of the deformable mirror DM is

It becomes.

FIG. 45B shows a state in which the principal ray RC and the paraxial ray RP are reflected and collected by the shape variable mirror DM when the incident angle θ of the principal ray incident on the shape variable mirror DM is larger than 0 °. , Shown on the yz plane. Here again, it is assumed that the free-form surface representing the shape of the reflecting surface of the deformable mirror DM has only a second-order coefficient, and the coefficients in the x-axis direction and the y-axis direction are C ₄ and C ₆ , respectively. Therefore, the parabola in the y-axis direction illustrated in FIG. 45B is represented by z = C ₆ y ² .

となるので、ｙｚ平面上における焦点距離、すなわち、平行光を入射角θで形状可変ミラーＤＭへ入射させたときの、入射点からｙ軸方向の近軸結像点までの距離をｆ_Yとすれば、ｆ_Yは以下の式によって与えられる。

45B, the incident angles of the principal ray RC and the paraxial ray RP to the deformable mirror DM are represented by θ and θ + δ, respectively, and tan δ = 2C ₆ from the relationship between δ and the parabola inclination at the point A ′. d / cos θ holds. If the distance from the incident point A ′ to the focused point F ′ after reflection is f _Y (d),

Therefore, the focal length on the yz plane, that is, the distance from the incident point to the paraxial imaging point in the y-axis direction when parallel light is incident on the deformable mirror DM at the incident angle θ is represented by f _Y. Thus, f _Y is given by

となる。 FIG. 45 (c) is a three-dimensional view of the ray diagram in FIG. 45 (b). Even if the incident angle θ is changed, the optical path obtained by projecting the principal ray RC and the paraxial ray RP onto the xz plane is exactly the same as when θ = 0 °, so the shape of the ray diagram projected onto the xz plane can be changed. The focal length of the mirror DM is f ₀ = 1 / 4C as in the equation (36). However, f ₀ is only the focal length in the ray diagram projected on the xz plane, and the actual focal length f _X due to the curvature in the x-axis direction of the deformable mirror DM can be seen from FIG.

It becomes.

In order to make the paraxial ray RP in the x-axis direction and the y-axis direction intersect the principal ray RC at substantially the same point, that is, in order to reduce astigmatism, it is desirable to satisfy f _X = f _Y. In other words, the conditions for reducing astigmatism by using Equation (38) and Equation (39) are:
(C ₄ / C ₆ ) cos ² θ = 1 (40)
It can be seen that it is.

  The above is an explanation of the fact that Expression (34) is satisfied. In order to realize a good imaging state including an area where a paraxial approximation is not satisfied and off-axis rays in an actual design, Expression (40) is Not exactly true. Nevertheless, it is not preferable that the value on the left side of the equation (40) deviates too much from 1.

Furthermore, in a state with the deformable mirror DM,
0.8 < | C ₄ / C ₆ | cos ² θ < 1.2 (41)
If this condition is satisfied, the astigmatism of the light beam reflected by the variable shape mirror can be further reduced.

Further, in a state where the deformable mirror DM is present,
0.1 < | C ₈ / C ₁₀ | cos ² θ < 10 (42)
It is desirable to satisfy.

  By satisfying Expression (42), the paraxial ray in the x-axis direction and the paraxial ray in the y-axis direction intersect with the axial principal ray at substantially the same point, and astigmatism on the image plane I is suppressed to an appropriate range. be able to. The reason is the same as that described above with reference to FIG.

Furthermore, in a state with the deformable mirror DM,
0.5 < | C ₈ / C ₁₀ | cos ² θ < 2 (43)
If this condition is satisfied, the astigmatism of the light beam reflected by the variable shape mirror can be further reduced.

Further, in a state where the deformable mirror DM is present,
_{0 <| (C 10 / C} 6) f | <10 ... (44)
It is desirable to satisfy.

  By satisfying the equation (44), it is not necessary to make the shape of the deformable mirror DM in the y-axis direction so complicated that the manufacturing cost of the deformable mirror device can be reduced.

Furthermore, in a state with the deformable mirror DM,
_{0 <| (C 10 / C} 6) f | <2 ... (45)
If it satisfies, decentration aberrations can be suppressed, which is even better.

  In the above embodiments, the central portion of the variable mirror is fixed. However, the central portion is not necessarily fixed, and the central portion may be changed, or the peripheral portion of the variable mirror may be fixed.

  In addition, as a driving method of the variable mirror, any type shown in the present application such as an electrostatic driving method, an electromagnetic driving method, a method using a piezoelectric effect, or the like may be used. If the electrostatic driving method is used, it is sufficient that the power consumption during mirror driving can be kept low. If an electromagnetic drive system is used, mirror drive control can be easily performed.

  In addition to the above optical system, it goes without saying that the present invention can also be used for robot eyes, mobile phones with an imaging function, door scope cameras, in-vehicle cameras, and the like.

Next, parameter values relating to the conditional expressions (32) to (34) and (41) to (45) of the first and second embodiments will be described.

  In an image pickup optical system used in a conventional image pickup apparatus, the object point distance is generally limited to a positive value. In Examples 1 and 2 according to the present invention, the object distance is a positive value and a negative value, but good imaging performance can be obtained even when the object distance is limited to a positive value. Needless to say.

  Further, in an observation optical system used in a conventional observation apparatus, there are a case where the diopter value indicating diopter generally changes continuously from positive to negative and a case where only negative. In Examples 1 and 2 according to the present invention, the diopter value representing diopter was changed from positive to negative, but good performance can be obtained even when the diopter value representing diopter is only negative. Needless to say.

  Finally, definitions of terms used in the present invention will be described.

  An optical device is a device including an optical system or an optical element. The optical device alone may not function. That is, it may be a part of the apparatus. The optical device includes an imaging device, an observation device, a display device, a lighting device, a signal processing device, and the like.

  Examples of the imaging device include a film camera, a digital camera, a robot eye, a lens interchangeable digital single-lens reflex camera, a television camera, a moving image recording device, an electronic moving image recording device, a camcorder, a VTR camera, and an electronic endoscope. A digital camera, a card-type digital camera, a TV camera, a VTR camera, a moving image recording camera, and the like are all examples of an electronic imaging device.

  Examples of the observation apparatus include a microscope, a telescope, glasses, binoculars, a loupe, a fiberscope, a viewfinder, a viewfinder, and the like.

  Examples of the display device include a liquid crystal display, a viewfinder, a game machine (Sony PlayStation), a video projector, a liquid crystal projector, a head mounted display (HMD), a PDA (personal digital assistant), There are mobile phones.

  Examples of the illumination device include a camera strobe, an automobile headlight, an endoscope light source, and a microscope light source.

  Examples of the signal processing device include a mobile phone, a personal computer, a game machine, an optical disk reading / writing device, an optical computer arithmetic device, and the like.

  The imaging device refers to, for example, a CCD, an imaging tube, a solid-state imaging device, a photographic film, and the like. The plane parallel plate is included in one of the prisms. The change of the observer includes the change of the diopter. The change in the subject includes a change in the object distance as the subject, movement of the object, movement of the object, vibration, blurring of the object, and the like.

The definition of the extended surface is as follows.
In addition to spherical surfaces, flat surfaces, and rotationally symmetric aspheric surfaces, spherical surfaces that are decentered with respect to the optical axis, flat surfaces, rotationally symmetric aspheric surfaces, aspheric surfaces that have a symmetric surface, aspheric surfaces that have only one symmetric surface, and non-symmetrical surfaces Any shape such as a spherical surface, a free-form surface, a non-differentiable point, or a surface having a line may be used. It may be a reflective surface or a refractive surface as long as it can have some influence on light. In the present invention, these are collectively referred to as an extended curved surface.

  The optical characteristic variable optical element includes a variable focus lens, a variable shape mirror, a polarization prism whose surface shape changes, a vertex angle variable prism, a variable diffractive optical element whose light deflection action changes, that is, a variable HOE, a variable DOE, and the like. The variable focus lens includes a variable lens in which the focal length does not change and the amount of aberration changes. The same applies to the deformable mirror. In short, an optical element whose light deflection action such as light reflection, refraction, and diffraction can be changed is called an optical characteristic variable optical element.

  An information transmission device is a device that can input and transmit any information such as a remote control such as a mobile phone, a fixed phone, a game machine, a TV, a radio cassette, a stereo, a personal computer, a keyboard of a personal computer, a mouse, a touch panel, etc. Point to. It shall also include a television monitor with an imaging device, a personal computer monitor, and a display. The information transmission device is included in the signal processing device.

As described above, the optical apparatus of the present invention has the following features in addition to the invention described in the claims.
[1] An imaging optical system having a rotationally symmetric lens and performing focusing using a deformable mirror.

[2] An observation optical system having a rotationally symmetric lens and performing diopter adjustment using a variable shape mirror.

[3] When the incident angle of the axial chief ray (hereinafter, chief ray) to the deformable mirror DM is θ,
5 ° < θ < 70 °
An imaging optical system or an observation optical system having a deformable mirror that satisfies the above.

[4] When the rear focal length of the optical system including the lens G and the deformable mirror DM is f,
_{0 <| C 4 f | <} 1 and _{0 <| C 6 f | <} 1
An imaging optical system or an observation optical system having a deformable mirror that satisfies the above.

[5] In a state where the deformable mirror DM is present,
0.1 < | C ₄ / C ₆ | cos ² θ < 10
An imaging optical system or an observation optical system having a deformable mirror that satisfies the above.

[6] In a state where the deformable mirror DM is present,
0.1 < | C ₈ / C ₁₀ | cos ² θ < 10
An imaging optical system or an observation optical system having a deformable mirror that satisfies the above.

[7] In a state where the deformable mirror DM is present,
_{0 <| (C 10 / C} 6) f | <10
An imaging optical system or an observation optical system having a deformable mirror that satisfies the above.

[8] An imaging optical system or observation optical system having a deformable mirror in which the shape of the reflecting surface of the deformable mirror DM does not become a convex surface in a certain state.

[9] An optical device using the optical system according to any one of claims 1 to 7.

1 is a schematic configuration diagram of a Kepler finder of a digital camera using an optical characteristic mirror according to an embodiment of the optical apparatus of the present invention. It is a schematic block diagram which shows the other Example of the deformable mirror 409 concerning this invention. It is explanatory drawing which shows one form of the electrode used for the deformable mirror of the Example of FIG. It is explanatory drawing which shows the other form of the electrode used for the deformable mirror of the Example of FIG. It is a schematic block diagram which shows the further another Example of the deformable mirror 409 concerning this invention. It is a schematic block diagram which shows the further another Example of the deformable mirror 409 concerning this invention. It is a schematic block diagram which shows the further another Example of the deformable mirror 409 concerning this invention. It is explanatory drawing which shows the state of the winding density of the thin film coil 427 in the Example of FIG. It is a schematic block diagram which shows the further another Example of the deformable mirror 409 concerning this invention. It is explanatory drawing which shows one example of arrangement | positioning of the coil 427 in the Example of FIG. FIG. 10 is an explanatory diagram showing another arrangement example of the coil 427 in the embodiment of FIG. 9. FIG. 12 is an explanatory diagram showing an arrangement of permanent magnets 426 that is suitable when the arrangement of the coil 427 is as shown in FIG. 11 in the embodiment shown in FIG. 7. An imaging system using a deformable mirror 409 applicable to an optical device according to still another embodiment of the present invention, such as a digital camera for a mobile phone, a capsule endoscope, an electronic endoscope, a digital camera for a personal computer, a PDA It is a schematic block diagram of the imaging system used for the digital camera etc. for cameras. It is a schematic block diagram of the variable shape mirror 188 which changes the lens surface by putting in and out the fluid 161 with the micro pump 180 based on the further another Example of the variable shape mirror of this invention. It is a schematic block diagram which shows one Example of the micropump applicable to this invention. It is a figure which shows the fundamental structure of the variable focus lens concerning this invention. It is a figure which shows the refractive index ellipsoid of a uniaxial nematic liquid crystal molecule. FIG. 17 is a diagram illustrating a state in which an electric field is applied to the polymer-dispersed liquid crystal layer illustrated in FIG. 16. FIG. 17 is a diagram illustrating a configuration of an example in the case where a voltage applied to the polymer-dispersed liquid crystal layer illustrated in FIG. 16 is variable. It is a figure which shows the structure of an example of the imaging optical system for digital cameras using the variable focus lens concerning this invention. It is a figure which shows the structure of an example of the variable focus diffractive optical element concerning this invention. It is a figure which shows the structure of the variable focus spectacles which have a variable focus lens using a twist nematic liquid crystal. It is a figure which shows the orientation state of a liquid crystal molecule when the voltage applied to the twist nematic liquid crystal layer shown in FIG. 22 is made high. It is a figure which shows the structure of the two examples of the variable declination prism concerning this invention. It is a figure for demonstrating the usage condition of the variable declination prism shown in FIG. It is a figure which shows the structure of an example of the variable focus mirror as a variable focus lens concerning this invention. It is a schematic block diagram of the imaging unit 141 using the variable focus lens 140 based on the further another Example of the optical apparatus of this invention. It is explanatory drawing which shows the modification of the variable focus lens in the Example of FIG. It is explanatory drawing which shows the state which the variable focus lens of FIG. 28 deform | transformed. It is a schematic block diagram of the variable focus lens 167 which changes the lens surface by putting in and out the fluid 161 with the micro pump 160 based on further another Example of the variable focus lens of this invention. FIG. 6 is a schematic configuration diagram of a variable focus lens 201 using a piezoelectric material 200 as another embodiment of the optical characteristic variable optical element according to the present invention. FIG. 32 is an explanatory diagram of a state of a variable focus lens according to a modification of FIG. 31. FIG. 6 is a schematic configuration diagram of a variable focus lens using two thin plates 200A and 200B made of a piezoelectric material, which is still another embodiment of the optical characteristic variable optical element according to the present invention. It is a schematic block diagram which shows other Example of the variable focus lens concerning this invention. FIG. 35 is a state explanatory diagram of a variable focus lens according to the example of FIG. 34; FIG. 5 is a schematic configuration diagram of a variable focus lens using still another embodiment of the optical characteristic variable optical element according to the present invention and using a photonic effect. It is explanatory drawing which shows the structure of the azobenzene used for the variable focus lens which concerns on the Example of FIG. 36, (a) is a trans | transformer type | mold and (b) has shown the cis type | mold. It is a schematic block diagram which shows the further another Example of the deformable mirror concerning this invention. FIG. 3 is an optical path diagram of a focusing optical system using the variable shape mirror of Example 1 of the present invention. It is an optical path figure of the optical system for focusing using the variable shape mirror of Example 2 of this invention. It is a conceptual diagram for demonstrating the curvature of field which generate | occur | produces with the eccentric reflective surface. It is a conceptual diagram for demonstrating the astigmatism which generate | occur | produces with the eccentric reflective surface. It is a conceptual diagram for demonstrating the coma aberration generate | occur | produced by the eccentric reflective surface. It is a conceptual diagram for demonstrating the focusing function and diopter adjustment function of this invention. It is a conceptual diagram for demonstrating the relationship between the incident angle of an axial principal ray, and the focal distance of an optical system.

Explanation of symbols

ST Aperture G Lens group DM Shape variable mirror O Object surface I Image surface M Concave mirror RC On-axis principal ray RP On-axis paraxial ray 45 Variable shape mirror 59 Transparent electrode 102 Lens 103 Control system 104 Imaging unit 140 Variable focus lens 141 Imaging Unit 142 Transparent member 143 Transparent material 144 Jelly-like material 145 Transparent electrode 146 Cylinder 147 Support member 148 Deformable member 161 Fluid 180 Micro pump 181 Diaphragm 182 and 183 Electrodes 184 and 185 Valve 188 Deformable mirror 189 Reflective film 160 Micro pump 167 Variable focus lens 163 Transparent substrate 164 Elastic body 165 Transparent substrate 200 Piezoelectric material 200A, 200B Thin plate 201 Variable focus lens 202 Substrate 204 Transparent substrate 206 Electrostrictive material 207 Variable focus lens 208, 209 Transparent elastic body 210 Azo Benzene 211 Transparent spacer 212, 213 Light source 214 Variable focus lens 404 Prism 405 Isosceles right angle prism 406 Mirror 408 Solid-state imaging device 409 Optical property variable shape mirror 409a Thin film (reflection surface)
409b Electrodes 409c, 409c ′ Piezoelectric element 409c-1 Substrate 409c-2 Electrostrictive material 409d Electrode 409e Substrate 409j Deformable substrate 409k Deformable electrode 411 Variable resistor 412 Power supply 413 Power switch 414 Arithmetic unit 415 Temperature sensor 416 Humidity sensor 417 Distance Sensor 423 Support base 424 Shake sensor 425 Drive circuit 426 Permanent magnet 427, 428 'Coil 428 Drive circuit 453 Electrostrictive material 452 Electrode 451 Deformable substrate 450 Reflective film 449 Buttons 508a, 508b, 509a, 509b Lens surface 511 Variable focus lens 512a First lens 512b Second lens 513a, 513b Transparent electrode 514 Polymer dispersed liquid crystal layer 515 Switch 516 AC power source 517 Liquid crystal molecule 518 Polymer cell 519 Variable resistance 521 Aperture 522 Lens 523 Solid-state imaging device 531 Variable focus diffractive optical element 532 First transparent substrate 532a First surface 532b Second surface 533 Second transparent substrate 533a Third surface 533b Fourth surface 539a, 539b Orientation Film 550 Variable focus glasses 551 Variable focus lens 552, 553 Lens 554 Twist nematic liquid crystal layer 555 Liquid crystal molecule 561 Variable deflection prism 562 First transparent substrate 562a First surface 562b Second surface 563 Second transparent substrate 563a First Third surface 563b Fourth surface 565 Variable focus mirror 566 First transparent substrate 566a First surface 566b Second surface 567 Second transparent substrate 567a Third surface 567b Fourth surface 568 Reflective film 901 Eyepiece 902 Objective lens

Claims (12)

  An imaging optical system that performs focusing using a variable optical property optical element.   An imaging optical system that performs focusing using a lens and an optical property variable optical element.   The imaging optical system according to claim 1, wherein the optical characteristic variable optical element has a free-form surface shape in at least one state.   The imaging optical system according to claim 1, wherein focusing is possible with respect to an object having a positive object point distance.   The imaging optical system according to claim 1, wherein focusing is possible with respect to an object whose object distance ranges from a positive region to a negative region.   An observation optical system that performs diopter adjustment using a variable optical property optical element.   An observation optical system that performs diopter adjustment using a lens and an optical property variable optical element.   The observation optical system according to claim 6 or 7, wherein the optical characteristic variable optical element has a free-form surface shape in at least one state.   9. The observation optical system according to claim 6, 7 or 8, wherein a diopter value representing diopter is negative.   9. The observation optical system according to claim 6, 7 or 8, wherein a diopter value representing a diopter continuously changes from positive to negative.   11. The optical system according to claim 1, wherein the optical characteristic variable optical element is a reflective optical characteristic variable optical element.   The optical system according to claim 1, wherein the optical characteristic variable optical element is a variable shape mirror.

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