JP4685907B2 - Imaging device - Google Patents

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 viewfinder of a digital camera or a TV camera, an observation optical system such as a telescope, a microscope, or a binocular, a spectacle, a video projector, a camera, a digital camera, a TV camera, and an endoscope.

  The conventional lens uses a lens manufactured by polishing glass or a lens manufactured by molding, and since the focal length cannot be changed by the lens itself, in order to perform focusing or zooming in a certain optical system Since the lens group needs to be moved in the optical axis direction, the mechanical structure is complicated.

JP 2000-131610 A

  In Patent Document 1, 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 an imaging optical system, a finder, a telescope, a binocular, and a microscope for a camera, a digital camera, a TV camera, and a mobile phone with an imaging function. These optical systems, such as observation optical systems such as endoscopes, surveillance cameras, and imaging optical systems for small digital cameras, have low power consumption, quiet sound, short response time, and simple mechanical structure. It is an object of the present invention to provide an optical system that contributes to cost reduction and is capable of focusing and zooming despite its small outer diameter and small size. 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.

The imaging device of the present invention has the following contents, for example.
(1) A zoom optical system having a variable mirror and a moving optical element group, the optical element group having a zooming function, and the variable mirror having a focusing function.
(2) The zoom optical system according to (1), wherein the moving optical element group has negative power.
(3) In an imaging apparatus that performs a mountain-climbing autofocus with a variable mirror, the deformation amount QR of the variable mirror is a deformation range obtained by adding at least a predetermined deformation amount to both ends of the deformation range necessary for focusing. deformed, the predetermined amount of deformation, the image pickup apparatus, which is a deformation amount required for changing the focus by one third of Sd determined by equation 370 below.

Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is.
(4) A zoom optical system having a variable mirror and a moving optical element group, the optical element group having a zooming function, and the variable mirror having a focusing function and a compensator function.
(5) The first optical element group, a variable mirror or variable focus lens disposed behind the first optical element group, and a variable magnification optical element group disposed behind the first optical element group, according to (1) to (4) Zoom optical system.
(6) The first optical element group, the variable mirror or the variable focus lens, the second optical element group or the air gap, the variable magnification optical element group, and the optical element group in order from the front to (1) to (5) The zoom optical system described.
(7) An imaging optical system characterized in that during zooming or focusing, the variable mirror is deformed and the entire variable mirror is translated in a direction substantially perpendicular to the mirror reflection surface.
(8) An imaging optical system characterized in that, during zooming or focusing, the entire variable mirror is translated in a certain direction along with the deformation of the variable mirror.
(9) When the maximum parallel movement amount of the entire variable mirror is x and the focal length of the optical system is f,
0 <| x | / f <1
An imaging optical system characterized by satisfying the above.
(10) The imaging optical system according to (9) subordinate to (7) or (8).
(11) The imaging optical system according to any one of (1) to (10), wherein there is one moving lens group.
(12) A variable mirror is provided, and the two optical element groups before and after a certain optical element group always move with the same movement amount for zooming, and the two moving groups have the same sign power, and A zoom optical system in which the power of the group sandwiched between the moving groups is opposite, and the variable mirror has a focus function or a compensator function.
(13) The zoom optical system according to (12), wherein the powers of the two moving groups are positive.
(14) The zoom optical system according to (12), wherein the powers of the two moving groups are negative.
(15) The zoom optical system according to (12), which includes a group having negative power in order from the front, a variable mirror, a front of the moving group, a group sandwiched between the moving groups, and a rear of the moving group.
(16) A zoom optical system having a variable mirror and a variable power group having a variable power function, wherein the variable mirror has a focusing function, and the variable mirror is disposed in front of the variable power group.
(17) A variable mirror and a moving optical element group, and the optical element group is a zooming group having a zooming function. The variable mirror has a focusing function and a compensator function, and is variable in front of the zooming group. A zoom optical system comprising a mirror.
(18) The zoom optical system according to any one of (16) to (17) subordinate to (7) to (15).
(19) The zoom optical system according to any one of (1) to (18), which includes a rotationally symmetric lens and a variable mirror.
(20) The zoom optical system according to any one of (1) to (18), which includes a rotationally symmetric lens and a variable mirror.
(21) The zoom optical system according to any one of (1) to (20), wherein Expressions 301 to 304 are satisfied.
(22) The zoom optical system according to any one of (1) to (20), wherein Expressions 305 to 309 are satisfied.
(23) The zoom optical system according to any one of (1) to (20), which satisfies expressions 311 to 314.
(24) The zoom optical system according to any one of (1) to (20), wherein Expressions 316 to 321 are satisfied.
(25) The zoom optical system according to any one of (1) to (20), wherein Expressions 322 to 323 are satisfied.
(26) The zoom optical system according to any one of (1) to (20), wherein Expressions 324 to 326 are satisfied.
(27) The zoom optical system according to any one of (1) to (20), wherein Expressions 327 to 329 are satisfied.
(28) The zoom optical system according to any one of (1) to (20), wherein Expressions 330 to 333 are satisfied.
(29) The zoom optical system according to any one of (1) to (20), wherein Expressions 335 to 336 are satisfied.
(30) The zoom optical system according to any one of (1) to (20), wherein Expressions 340 to 347 are satisfied.
(31) The zoom optical system according to any one of (1) to (20), wherein at least two of Expressions 301 to 347 are satisfied.
(32) The zoom optical system according to (1) to (20), wherein at least one of expressions 340 to 347 and at least one of expressions 301 to 336 are satisfied.
(33) The zoom optical system according to any one of (1) to (29), wherein the aperture stop is located behind the variable mirror.
(34) The zoom optical system according to any one of (1) to (16), wherein the moving optical element group has positive power.
(34 ′) The zoom optical system according to any one of (1) to (16), wherein the moving optical element group has negative power.
(35) An image pickup apparatus having a variable mirror driven by static electricity, wherein the shape of the variable mirror is concave within the range of the object distance to be imaged at the time of shooting.
(36) In an imaging apparatus having a hill-climbing type autofocus that changes a focus on an object, detects a high-frequency component of a captured object image, and determines that the in-focus state when the high-frequency component becomes maximum, The imaging device according to (35).
(37) An imaging apparatus including a state in which the shape of the variable mirror is flat when changing the focus with respect to the object when performing autofocus in (36).
(38) In an imaging apparatus that performs a hill-climbing autofocus with a variable mirror, the deformation amount QR of the variable mirror is a deformation range obtained by adding at least a predetermined deformation amount to both ends of the deformation range necessary for focusing. deformed, the predetermined amount of deformation, the image pickup apparatus, which is a deformation amount required for changing the focus only Sd determined by the formula 370.
(39) In an imaging apparatus that performs a hill-climbing autofocus having a zoom optical system having a variable mirror, the deformation amount QR of the variable mirror is at least predetermined at both ends of a deformation range necessary for focusing and compensator The imaging apparatus according to claim 1, wherein the imaging device is deformed within a deformation range including a deformation amount, and the predetermined deformation amount is a deformation amount necessary to change the focus by Sd determined by Expression 370.
(40) In an imaging apparatus that performs a mountain climbing type autofocus with a zoom optical system with a variable mirror, in addition to the variable mirror deformation amount QR necessary as a focus and a compensator, at least Sd determined by Expression 370 An image pickup apparatus having a variable mirror that has a deformation amount necessary to change the focus by 1/3 of both ends of the QR.
(41) The imaging device according to any one of (3) and (38) to (40) having the characteristics described in (35).
(42) An imaging apparatus that includes a variable mirror and performs active autofocus.
(43) An electronic imaging apparatus that includes a variable mirror and an imaging element and performs active autofocus.
(44) The imaging device according to (35) to (43) including the optical system according to (1) to (34 ′).
(45) An imaging device that satisfies Expression 102.
(46) An image pickup apparatus including the optical system according to any one of (1) to (34 ′), including an image pickup element, wherein the positional relationship between the optical element closest to the object and the image pickup element is fixed.
(47) The imaging apparatus according to (44), further including an imaging element, wherein the positional relationship between the optical element closest to the object and the imaging element is fixed.
(48) The optical system or the imaging device according to any one of (1) to (47), wherein a normal mirror is used instead of the variable mirror.
(49) The optical system or the imaging apparatus according to any one of (1) to (47), wherein a variable focus lens is used instead of the variable mirror.

  The deformable mirror is one of the deformable mirrors, and is a mirror that can freely change the optical power or the 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 it is desirable that the variable mirror is a rotationally asymmetric surface or a free-form surface in order to improve 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 perpendicular to the optical axis and perpendicular 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, the spherical aberration generated by the spherical surface, coma aberration, field curvature, and other aberrations are corrected with 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 beam incident on a concave mirror decentered from an object point at infinity is reflected and imaged by hitting the concave mirror, but after the light beam hits the concave mirror, the back focal length to the image plane is the light beam when the image field side is air. It becomes half the radius of curvature of the part hit. Then, as shown in FIG. 14, an image plane tilted 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. Further, by arranging a rotationally asymmetric surface having the same effect as the above configuration in the optical system separately from the concave mirror M, a flat image surface can be obtained with a small number of components.

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.

  Next, 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 prism, 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.

As described above, according to the present invention, by using the deformable mirror, it is possible to perform zooming and focusing only by changing the surface shape of the mirror without driving the lens group back and forth. Etc. can be provided.
The free-form surface used in the present invention is defined by the following equation (a). The Z axis of this defining formula is the axis of the free-form surface.

Z = cr ² / [1 + √ {1- (1 + k) c ² r ² }]
+ Σ _{(j = 2} to ₆₆₎ CjX ^m Y ⁿ (a)
Here, the first term of the above formula (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.

The free-form surface term is
Σ _{(j = 2} to ₆₆₎ CjX ^m Y ⁿ
= C ₂ X + C ₃ Y +
+ C ₄ X ² + C ₅ XY + C ₆ Y ²
+ C ₇ X ³ + C ₈ X ² Y + C ₉ XY ² + C ₁₀ Y ³
+ C ₁₁ X ⁴ + C ₁₂ X ³ Y + C ₁₃ X ² Y ² + C ₁₄ XY ³ + C ₁₅ Y ⁴
+ C ₁₆ X ⁵ + C ₁₇ X ⁴ Y + C ₁₈ X ³ Y ² + C ₁₉ X ² Y ³ + C ₂₀ XY ⁴ + C ₂₁ Y ⁵
+ C ₂₂ X ⁶ + C ₂₃ X ⁵ Y + C ₂₄ X ⁴ Y ² + C ₂₅ X ³ Y ³ + C ₂₆ X ² Y ⁴ + C ₂₇ XY ⁵ +
C ₂₈ Y ⁶
+ C ₂₉ X ⁷ + C ₃₀ X ⁶ Y + C ₃₁ X ⁵ Y ² + C ₃₂ X ⁴ Y ³ + C ₃₃ X ³ Y ⁴ + C ₃₄ X ² Y ⁵
+ C ₃₅ XY ⁶ + C ₃₆ Y ⁷ ...
However, Cj (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.

  Further, another defining formula of the free-form surface that is the surface of the rotationally asymmetric curved surface can be defined by a Zernike polynomial. The shape of this surface is defined by the following equation (b). The Z-axis in equation (b) is 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, A is the distance from the Z axis in the XY plane, R is the azimuth around the Z axis, and Z 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 si
n (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 of 2 or more) is a coefficient. In order to design an optical system that is 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 above definition formula is shown for illustration of 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.

In the present invention, all 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.
For the decentered surface, the amount of decentering from the center of the reference plane of the optical system to the top position of the surface (X, Y, and Z axes are X, Y, and Z, respectively) and the center of the surface Axes (for free-form surfaces, inclination angles (α, β, γ (°), respectively) about the Z axis in the above equation (a) are given.

  Further, as for the order of eccentricity, after the eccentricity in the X, Y, and Z directions is performed, the coordinate system is rotated in the order of α, β, and γ. That coordinate system becomes the local coordinates of the mirror surface. Thereafter, in order to define the coordinate system of the reflected ray, the definition coordinate system is defined by rotating the coordinate system again in the order of α, β, and γ.

When only the tilt of the reflecting surface is shown, the tilt angle of the central axis of the surface is given as the amount of eccentricity.
The aspherical shape is expressed by the following equation (c) where z is the optical axis direction, y is the direction orthogonal to the optical axis, k is the conic coefficient, and a, b, c, and d are the aspheric coefficients. Is done.

z = (y ² / r) / [1+ {1− (1 + k) · (y / r) ² } ^1/2 ] + ay ⁴
+ By ⁶ + cy ⁸ + dy ¹⁰ (c)
The explanation regarding the numerical data is common to the numerical data of each embodiment of the present invention.

As is clear from the above description, according to the imaging apparatus of the present invention, the power consumption is small, the sound is quiet, the response time is short, the mechanical structure is simple and contributes to cost reduction, and the outer diameter is small. An imaging device capable of focusing and zooming despite the small size can be provided.

  FIG. 8 shows an example 302 (Example 8 to be described later) of the present invention, which is an example 302 of a 1.8 × zoom optical system used in an electronic imaging system such as a digital camera or a TV camera using a variable mirror 301.

  A first group 305 composed of a convex lens 303 and a concave lens 304, a lens group 306 placed behind it, a variator (magnification group) 307 having a concave power 307, a convex lens 308, and a fourth group composed of a 309 concave lens 310. 311. Reference numeral 307 moves on the straight line parallel to the Z axis, and zooming is performed. At this time, focus movement occurs, but compensation is made by deforming 301. That is, 301 has the function of a compensator. Further, when the object distance is changed, the image can be formed on 408 by deforming 301. That is, when focusing, it is not always necessary to move the lens. 301 has two functions of a compensator and a focus.

  When zooming with a concave lens, there is an advantage that the same zooming ratio can be obtained with a small amount of movement compared to when zooming is performed by moving a convex lens. In order to obtain a higher performance zoom optical system, it is desirable to satisfy at least one of the following conditional expressions in at least a certain zoom state.

If βv is the magnification of the variator, 0.3 <| βv | <6 Equation 301
If the condition is satisfied, the total length of the optical system may be shortened. This is because the object-to-image distance Io of the lens system is minimum when the magnification is −1 as shown in Expression 306. That is, it is preferable to include a zoom state in which the absolute value of the variator magnification is 1.

0.5 <| βv | <4.0 Formula 302
If so, a smaller zoom optical system can be obtained.
0.6 <| βv | <2.5 Expression 303
Then, further downsizing is possible. Especially when the variator is concave power 0.7 <βv <3.0 Equation 304
If so, further miniaturization is possible.

When the variator magnification at the wide-angle end is βvw and the variator magnification at the telephoto end is βvT, βvw · βvT <5 Equation 305
It is good to satisfy. This is because when the same zoom ratio is realized, the object-to-image distance Io of the variator can be minimized when βvw · βvT = 1. The object-image distance Io is Io = fv (−βv−1 / βv + 2) Equation 306
Therefore, the above conclusion can be obtained. Where fv is the focal length of the variator.

Furthermore, 0.3 <βvw · βvT <3 (Formula 307)
If so, the size can be further reduced. Where βv is the magnification of the variator. Further, since the deformation amount of the variable mirror as the compensator becomes small near βv = −1, the aberration can be improved.

0.5 <βvw · βvT <2 Equation 308
And that's even better. If the variator has positive power,
0.8 <βvw · βvT <1.6 Equation 309
Then, a smaller zoom lens can be obtained. Aberration is also improved for the same reason as in equations 307 and 308.

  The focal length fv of the variator desirably satisfies the following expression 311. f is the focal length of the entire 302. Note that f varies depending on the azimuth angle when the variable mirror has a free-form surface shape, but in the present invention, the focal length calculated by the paraxial ray in the YZ plane is defined as f. In the calculation of f, the power of the variable mirror is ignored.

−3 <fv / f <15 Formula 311
If the value of fv / f falls below the lower limit, the zooming efficiency due to the concave power is reduced, and the effect as a zoom lens is diminished. If the value of fv / f exceeds the upper limit, Io increases from Equation 306, which is not preferable because the total lens length increases.

-2 <fv / f <5 Formula 312
If so, it is advantageous to further reduce the size of the lens. Further, from Equation 306, the smaller | fv |

0.5 <fv / f <5 Formula 313
This is advantageous because the power of the variator becomes positive and it is easy to lower the principal ray height at wide angle.

−3 <fv / f <−0.2 Formula 314
If this is the case, the power of the variator becomes negative, which is advantageous because the magnification can be greatly changed with a small amount of lens movement.

The focal length f1 of the first group preferably satisfies the following expression 316.
f1 / f <0 Formula 316
This is because the first lens unit has a concave power, which is advantageous for a retro-focus type and a wide-angle lens. Further, the lower limit of the following expression 318 is also necessary so that the absolute value of the magnification β4 of the fourth group does not become too small. Because, if the power of the variable mirror is small, this is ignored. F = f1 · β2 · βv · β4 Equation 317
However, assuming that | β2 | ≈1 and | βv | ≈1, f1β4 is in an inversely proportional relationship when f is fixed. Here, β2 is the magnification of the optical system sandwiched between the variable mirror and the variator. When the optical system has an air gap, β2 = 1.

−20 <f1 / f <−0.2 Formula 318
If this is the case, the occurrence of aberrations that occur in the lens system prior to the fourth group may be suppressed by decreasing | β4 |. If f1 / f exceeds the upper limit of Expression 319, the Petzval sum becomes too negative, and field curvature aberration occurs, which is disadvantageous.

−12 <f1 / f <−0.6 Formula 319
This is more advantageous in terms of aberration. If the variator has a convex power, −5 <f1 / f <−0.6 Formula 320
If so, it is more advantageous in widening the angle and aberration. If the variator is concave power −20 <f1 / f <−1 Equation 321
If so, the height of the light beam in the first lens group can be suppressed, which is advantageous in reducing the size of the lens.

The optical system from the variator to the image plane in the rear group is called the fourth group. When the magnification of the fourth group is β4,
0.1 <| β4 | <1.3 Expression 322
It is desirable that When | β4 | is below the lower limit, the aberration generated in the fourth group increases. If | β4 | exceeds the upper limit, | f1 | becomes too small from Equation 317, and the Petzval sum becomes too negative.

0.2 <| β4 | <0.9 Expression 323
If it is, it is still better in terms of aberration.

The front focal position of the optical system combining the variator and the second group is Hv (the sign is measured with the light traveling direction positive and the forefront surface top of the second group as the origin. The second group is a variable mirror and If it is an optical system between variators, air spacing may be used)
−0.2 <−Hv / fv Expression 324
It is desirable that This is because a space for placing the variable mirror in front of the variator is necessary, so that the variator cannot be put forward, and this prevents the variable range of the variator from being limited.

−0.07 <−Hv / fv <30 Formula 325
And that's even better.
When the variator has a convex power, 0 ≦ −Hv / fv <2 Equation 326
If this is the case, the variator is not a strong teletype and is advantageous in terms of aberration.

If Dkv is the air-converted length from the variable mirror to the variator (the sign is positive when the light travels in the positive direction) 0 ≦ | (Dkv + Hv) / fv | <3 Equation 327
It is desirable that Dkv + Hv is an amount indicating how much the principal point position of the variator + second group optical system is “deviation” with respect to the variable mirror. The smaller this “deviation”, the smaller the deformation amount of the variable mirror. This is advantageous in that the generation of aberration is reduced.

0 ≦ | (Dkv + Hv) / fv | <2 Expression 328
If it is better.
If the variator is concave power,
| (Dkv + Hv) / fv | <500 Expression 329
If it is. If the value of | (Dkv + Hv) / fv | exceeds the upper limit value, it will be difficult to correct the aberration.

Dok is the distance from the final surface of the first group to the variable mirror, and Fbo is the back focal position of the first group measured from the final surface of the first group. Both Dok and Fbo are assumed to be positive in the direction in which the light beam travels. When the variator is positive power 0 <(Dok−Fbo) / fv <5 Formula 330
It is good to satisfy. Dok-Fbo gives the distance from the variable mirror to the first group of images. However, since the variator magnification is near -1, if the variator principal point is near the variable mirror, (Dok-Fbo) / fv≈2
At this time, the deformation amount of the variable mirror can be minimized and the aberration can be reduced. Accordingly, the aberration increases regardless of whether the upper limit or the lower limit of Expression 330 is deviated.

0.3 <(Dok-Fbo) / fv <3.5 Formula 331
If it is better. When the variator has a concave power, −60 <(Dok−Fbo) / fv <−3 Equation 332
If so, the object point for the optical system after the first group is sufficiently far away, and aberrations can be reduced. However, if (Dok−Fbo) / fv is lower than the lower limit of the expression 332, the first group protrudes greatly forward, and the lens system becomes large or | f1 | becomes large and it becomes difficult to widen the angle. If the upper limit is exceeded, the object point for the optical system after the first group will be close and the aberration will increase.

−30 <(Dok−Fbo) / fv <−5 Expression 333
If it is better.
When the fourth group is a fixed group, an aspherical surface is preferably provided therein. This is because there is little tilting of the field curvature that occurs in the case of a short-distance object (bending of the image plane in the direction opposite to the direction in which the light beam travels).

The incident angle Φ of the on-axis light beam on the variable mirror is 39 ° <Φ <55 ° (Formula 335)
However, in the case of a rectangular parallelepiped body such as a TV camera or a digital camera, it is advantageous in terms of design, machine design, processing, and assembly.

40 ° <Φ <50 ° ・ ・ ・ Equation 336
If it is better.
A variable focus lens may be used instead of the variable mirror. Most of the above formulas are based on paraxial theory, so they are also valid for variable focus lenses.

  In addition, as is common to the optical system of the present invention, it is preferable to arrange the aperture stop behind the variable mirror. This is because if the lens is arranged in front of the variable mirror, the distance from the stop to the rear group of the variable mirror becomes too long, and the principal ray height becomes too high in the rear group of the stop, making it difficult to correct off-axis aberrations.

  FIG. 17 shows the deformation amount (dent amount) of the variable mirror and the operation of the imaging system. The optical system of the imaging apparatus may be a zoom optical system or a single focus optical system. At the time of photographing, the shape of the variable mirror is in Q to R in the figure. A shape between P2 and R2 is taken at the time of autofocus operation before photographing. P to P2 and R2 to S are margins for absorbing variations in manufacturing errors, but P2 may coincide with P and R2 may coincide with S.

The amount of change in the dents of P2Q and RR2 is the depth of focus Sd of the imaging system:
Sd = k × P × Fno Expression 370
It is better to be larger than the amount of dent required to change the focus by that amount. This is because it is easier to detect the focus position if the object image is blurred to some extent when searching for the focus by autofocus. However,
Px: dimension of one pixel of the image sensor in the x direction Py: dimension of one pixel of the image sensor in the y direction P = √ (Px · Py)
Fno: F number of the photographing optical system k: constant (takes a value between 2 and 3)
It is.

  Furthermore, if the amount of depression of P2Q and RR2 is set to an amount corresponding to a focus change that is twice or more of Sd, the accuracy of autofocusing is better. It is even better if the amount corresponds to a focus change of 4 times or more of Sd.

  If the deformation amount of the variable mirror cannot be taken large, the change in the amount of depression of P2Q and RR2 may be about 1/3 of Sd. This is because autofocusing is possible for most subjects except for subjects with low contrast.

  In the above discussion, the case where the deformable mirror is deformed is described. However, the present invention is not limited to this, and in either case of the convex deformation or the concave deformation of the variable mirror, the change in the deformation amount of Expression 370 and P2Q and RR2 It goes without saying that the conditions can be applied including the following discussion.

  In the case of an imaging apparatus having a zoom optical system, QR may include a deformation amount as a compensator accompanying zooming. Of course, when the variable mirror does not have the function of the compensator, it is sufficient to include only the focus adjustment amount as the QR.

  In the case of an active method in which infrared light or the like is projected onto a subject and distance measurement is performed from reflected light intensity as an autofocus method, deformation corresponding to P2Q and RR2 is unnecessary, and the deformation amount of the variable mirror can be reduced. The aberration of the imaging optical system may be reduced.

  It goes without saying that the optical system according to the embodiment of the present invention can be combined with either the hill-climbing method or the active method autofocus method. Or you may combine with the autofocus which uses both systems together.

  Example 4 to be described later is an example using the above-described contrast autofocus, and k = 2 and P = 2.5 μm.

  As is common to the present invention, the focal length of the entire optical system is denoted by f. f is the focal length calculated by assuming that the variable mirror is concave or convex as a flat surface, that is, the focal length of the system excluding the variable mirror.

  Further, it is desirable that the variable mirror is disposed in front of a lens group that mainly performs zooming. Because if the variable mirror has a focusing function, the power of the variable mirror is changed with the change of the object distance, but if the variable magnification group is located behind the variable mirror, the object distance is changed regardless of the magnification of the variable magnification group. Accordingly, focusing may be performed by changing the power of the variable mirror, and the concept is simple in terms of optical design and control of the variable mirror, and it is easy to design the imaging system. This merit can be said whether the variable mirror has a compensator function or not.

Hereinafter, although an Example is hung up, the lens and imaging device except a variator are being fixed to the lens frame etc. There are an embodiment in which the center portion of the variable mirror is fixed and an embodiment in which the peripheral portion is fixed.
Embodiments of an imaging apparatus according to the present invention will be described below with reference to the drawings.

Cross-sectional views of Examples 1 to 13 are shown in FIGS.
In the lens data of Examples 1 to 13, “ASP” is an aspherical surface, “FFS” is a free-form surface, “DM” is a deformable mirror, and “OB” is an object distance. Refractive index and Abbe number are those of d line (587.56nm). The unit of length is mm. The variable distance Di (i = 1, 2,...) Represents values at the wide-angle end to the standard to the telephoto end in order in the first to eighth and thirteenth embodiments, and sequentially from the telephoto end to the standard to wide-angle in the ninth to twelfth embodiments. Represents the value at the end. Even if the object distance is different, the distance Di is the same value if the zoom state notation (“wide angle”, “standard”, “telephoto”) is the same. In each of the embodiments, two parallel flat plates are inserted on the most image plane side. This assumes a cover glass, an IR cut filter, and a low-pass filter of the image sensor.

Terms relating to free-form surfaces, aspheric surfaces, etc., for which no data is described, are zero.
The values of the conditional expressions for each example are shown in the table of FIG.

Example 1
Object distance Zoom Focal length Diagonal angle of view 1 ∞ Wide angle 4.125 62.44 °
Condition 2 ∞ Standard 5.775 46.82 °
State 3 ∞ Telephoto 7.425 37.22 °
State 4 300mm Wide angle state 5 300mm Standard state 6 300mm Telephoto
Fno .: 2.84 to 3.50
Imaging surface size: 4.4mm x 3.3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -20.37 1.00 1.6346 52.3
2 ASP [1] 8.53
3 ∞ 0.00
4 FFS [1] (DM) 0.00 Eccentricity [1]
5 ∞ -4.50
6 -6.53 -1.50 1.6575 33.0
7 -4.97 -0.31
8 -5.73 -2.46 1.7440 44.8
9 -6.93 D1 = -5.38 to -2.61 to -0.70
10 Diaphragm surface -0.30
11 ASP [2] -1.65 1.5891 61.1
12 42.39 -1.13
13 -5.33 -2.23 1.4875 70.4
14 6.58 -0.87
15 5.84 -1.16 1.7545 28.2
16 -3.91 D2 = -1.36 to -4.13 to -6.04
17 -9.07 -1.69 1.6167 60.5
18 ASP [3] -0.61
19 ∞ -1.44 1.5477 62.8
20 ∞ -0.80
21 ∞ -0.60 1.5163 64.1
22 ∞ -0.30
Image plane ∞
ASP [1]
Curvature radius 10.74, k 0.0000
a -3.1561 × 10 ^-4 , b 7.4345 × 10 ^-6 , c -2.9402 × 10 ^-7 , d 3.8352 × 10 ^-9
ASP [2]
Radius of curvature -7.58, k 0.0000
a 7.2406 × 10 ^-4 , b 3.3243 × 10 ^-5 , c -2.1395 × 10 ^-6 , d 6.9150 × 10 ^-7
ASP [3]
Curvature radius 6.09, k 0.0000
a -3.0714 × 10 ^-3 , b 1.1814 × 10 ^-4 , c -4.5515 × 10 ^-6 , d 6.6703 × 10 ^-8
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
C4 -3.9028 × 10 ^-4 0.0000 -2.1318 × 10 ^-4 -7.1316 × 10 ^-4 -2.7737 × 10 ^-4
-5.3988 × 10 ^-4
C6 -2.0669 × 10 ^-4 0.0000 -1.1191 × 10 ^-4 -3.8008 × 10 ^-4 -1.4380 × 10 ^-4
-2.7559 × 10 ^-4
C8 -1.1153 × 10 ^-5 0.0000 -1.1113 × 10 ^-6 -1.1264 × 10 ^-5 -1.0592 × 10 ^-6
-5.0322 × 10 ^-6
C10 -4.8904 × 10 ^-6 0.0000 -2.1291 × 10 ^-6 -6.9295 × 10 ^-6 -1.7984 × 10 ^-6
-4.2218 × 10 ^{-6
C11 1.2709 × 10 -5 0.0000 -1.4733 ×} 10 -6 1.5502 × 10 -5 3.1151 × 10 -7 -
1.0475 × 10 ^-6
C13 1.3639 × 10 ^-5 0.0000 -5.5535 × 10 ^-7 1.6105 × 10 ^-5 1.7493 × 10 ^-6 9
.5344 × 10 ^-7
C15 3.2175 × 10 ^-6 0.0000 -2.1544 × 10 ^-7 3.7671 × 10 ^-6 -1.5870 × 10 ^-7
-3.8757 × 10 ^-7
Eccentric [1]
X 0.00 Y decy Z decz
α 45.00 β 0.00 γ 0.00
State 1 State 2 State 3 State 4 State 5 State 6
decy 0.003 0 0.003 0.007 0.004 0.005
decz 0.003 0 0.003 0.007 0.004 0.005

  The first embodiment is an example of an imaging apparatus 100 for a digital camera using a variable mirror as shown in FIG.

  This embodiment includes four lens groups, one variable mirror, a parallel plate, and a solid-state image sensor. The variable mirror 102 is disposed between the first lens group 101 having negative power and the second lens group 103 having meniscus positive power. The third lens group 104 is a variator having positive power and moves in a direction parallel to the optical axis in order to change the angle of view of the optical system. The fourth lens group 105 is a lens group that is disposed in front of the solid-state image sensor 107 and has positive power. The parallel plate 106 represents an infrared cut filter, a low-pass filter, a cover glass of an image sensor, and the like.

  In this embodiment, the third lens group 104 functions as a variator, and the variable mirror functions as a compensator and for focusing when the object distance changes, so that a zoom ratio of 1.8 times can be achieved. It is an optical system.

(Example 2) ↓
Object distance Zoom Focal length Diagonal angle of view 1 ∞ Wide angle 4.2 61.53 °
State 2 ∞ Standard 6.3 43.29 °
State 3 ∞ Telephoto 8.4 33.15 °
State 4 300mm Wide angle state 5 300mm Standard state 6 300mm Telephoto
Fno .: 2.84 to 3.49
Imaging surface size: 4.4mm x 3.3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -16.83 1.01 Eccentricity [1] 1.7748 50.1
2 ASP [1] 6.51 Eccentricity [1]
3 ∞ 0.00
4 FFS [1] (DM) 0.00 Eccentricity [3]
5 ∞ -4.00
6 -7.66 -1.37 1.7359 31.0
7 -6.63 -0.16
8 -11.46 -1.20 1.7850 45.2
9 -26.59 D1 = -8.05 to -3.73 to -0.10
10 Diaphragm surface -0.10
11 ASP [2] -2.50 Eccentricity [4] 1.5764 60.3
12 -43.52 -1.38 Eccentricity [4]
13 -5.62 -2.53 Eccentric [5] 1.4900 70.0
14 6.86 -0.87 Eccentric [5]
15 5.31 -1.00 Eccentric [6] 1.7625 28.2
16 ASP [3] D2 = -0.62 ~ -4.95 ~ -8.58
Eccentric [6]
17 -7.77 -2.75 1.5111 67.0
18 6.00 -0.18
19 5.46 -1.47 1.7441 42.1
20 ASP [4] -0.46
21 ∞ -1.44 1.5477 62.8
22 ∞ -0.80
23 ∞ -0.60 1.5163 64.1
24 ∞ -0.50
Image plane ∞ 0.00 Eccentricity [7]
ASP [1]
Curvature radius 8.84, k 0.0000
a -7.3333 × 10 ^-4 , b 2.0902 × 10 ^-5 , c -1.4698 × 10 ^-6 , d 3.8957 × 10 ^-8
ASP [2]
Radius of curvature -6.92, k 0.0000
a 3.4834 × 10 ^-4 , b 1.2367 × 10 ^-5 , c 6.8848 × 10 ^-7 , d 7.0789 × 10 ^-8
ASP [3]
Radius of curvature -5.12, k 0.0000
a -1.5211 × 10 ^-3 , b 5.1273 × 10 ^-5 , c -1.1665 × 10 ^-5 , d 6.4114 × 10 ^-7
ASP [4]
Curvature radius 5.65, k 0.0000
a -2.5044 × 10 ^-3 , b 1.0252 × 10 ^-4 , c -4.3124 × 10 ^-6 , d 8.6293 × 10 ^-8
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
C4 -7.7351 × 10 ^-4 0.0000 -3.6890 × 10 ^-4 -1.0612 × 10 ^-3 -2.8544 × 10 ^-4
-6.5807 × 10 ^-4
C6 -3.8970 × 10 ^-4 0.0000 -1.8472 × 10 ^-4 -5.3605 × 10 ^-4 -1.4050 × 10 ^-4
-3.3171 × 10 ^-4
C8 -1.7161 × 10 ^-5 0.0000 -1.0527 × 10 ^-5 -2.1366 × 10 ^-5 -8.9812 × 10 ^-6
-1.6304 × 10 ^-5
C10 -8.1320 × 10 ^-6 0.0000 -5.5679 × 10 ^-6 -1.0448 × 10 ^-5 -3.9280 × 10 ^-6
-1.0714 × 10 ^{-5
C11 1.2801 × 10 -5 0.0000 -3.3904 ×} 10 -7 1.5724 × 10 -5 4.9259 × 10 -7 -
1.4891 × 10 ^{-6
C13 1.3267 × 10 -5 0.0000 -8.2321 ×} 10 -7 1.5533 × 10 -5 1.8986 × 10 -6 -
8.0202 × 10 ^-7
C15 2.9429 × 10 ^-6 0.0000 -2.2205 × 10 ^-7 3.3239 × 10 ^-6 -2.2832 × 10 ^-7
-7.4651 × 10 ^-7
Eccentric [1]
X 0.00 Y 0.12 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [3]
X 0.00 Y decy Z decz
α 45 β 0.00 γ 0.00
State 1 State 2 State 3 State 4 State 5 State 6
decy 0.005 0 0.003 0.007 0.004 0.005
decz 0.005 0 0.003 0.007 0.004 0.005
Eccentric [4]
X 0.00 Y -0.07 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [5]
X 0.00 Y -0.05 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [6]
X 0.00 Y -0.04 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [7]
X 0.00 Y -0.03 Z 0.00
α -1.74 β 0.00 γ 0.00

  The second embodiment is an example of an imaging apparatus 108 for a digital camera using a variable mirror as shown in FIG.

  This embodiment has substantially the same configuration as the first embodiment, but the fourth lens group is made up of two lenses, so that various aberrations such as lateral chromatic aberration are suppressed, and the zoom ratio is 2.0 times. The optical system can be doubled.

  In this embodiment, each lens of the first lens group 109 and the third lens group 112 and the imaging surface of the solid-state imaging device are decentered in the direction perpendicular to the z axis (the direction of the arrow in FIG. 2). . Further, a tilt with the X axis as the center of rotation is added to the imaging surface of the solid-state imaging device. The deformable mirror 110 is deformed into a free-form surface to suppress decentration aberrations due to reflection. However, lens decentering and imaging surface tilt are effective for remaining decentration aberrations.

By adding decentration in the direction of the arrow in FIG. 2, there is an effect of suppressing trapezoidal distortion unique to the bending optical system.
When the amount of decentration added to each lens is Δ and the focal length of the optical system is f,
0 <| Δ | / f <0.2 Expression 101
It is desirable that

  By decentering the lens within the range of Formula 101, it is possible to effectively suppress aberrations such as trapezoidal distortion. When the upper limit of 0.2 is exceeded, the amount of decentration becomes too large, and the aberration of peripheral rays becomes large, so that it is difficult to correct aberrations in a balanced manner.

In addition, when the tilt amount added to the imaging surface of the solid-state imaging device is C (deg),
0 <| C | <15 (Formula 102)
It is desirable that

  By decentering the lens within the range of Expression 102, it is possible to effectively suppress aberration including an asymmetric component. If the upper limit of 10 is exceeded, the difference between the principal ray tilt angles of incident light at both ends of the image surface becomes too large, and the brightness at both ends of the image surface changes due to shading or the like.

0 <| C | <8 (Formula 103)
If so, it is still better in terms of shading.
0 <| C | <3 Formula 103-2
Even better.

(Example 3)
Object distance Zoom Focal length Diagonal angle of view 1 ∞ Wide angle 4.2 61.53 °
State 2 ∞ Standard 6.3 43.29 °
State 3 ∞ Telephoto 8.4 33.15 °
State 4 150mm Wide angle state 5 150mm Standard state 6 250mm Telephoto
Fno .: 2.84 to 3.49
Imaging surface size: 4.4mm x 3.3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -19.22 1.00 Eccentricity [1] 1.7800 50.0
2 ASP [1] 6.57 Eccentricity [1]
3 ∞ 0.00
4 FFS [1] (DM) 0.00 Eccentricity [3]
5 ∞ -4.00
6 -7.55 -1.45 1.7742 26.1
7 -6.44 -0.20
8 -10.73 -1.29 1.7888 43.6
9 -24.90 D1 = -8.53 to -3.97 to -0.20
10 Diaphragm surface -0.10
11 ASP [2] -2.35 Eccentric [4] 1.5755 60.3
12 -55.56 -1.34 Eccentricity [4]
13 -5.75 -2.61 Eccentricity [5] 1.4900 70.0
14 6.87 -0.83 Eccentric [5]
15 5.53 -1.00 Eccentric [6] 1.7646 28.8
16 ASP [3] D2 = -0.62 ~ -5.18 ~ -8.95
Eccentric [6]
17 -7.35 -2.80 1.4900 70.0
18 6.58 -0.21
19 6.00 -2.02 1.6773 45.5
20 ASP [4] -0.30
21 ∞ -1.44 1.5477 62.8
22 ∞ -0.80
23 ∞ -0.60 1.5163 64.1
24 ∞ -0.50
Image plane ∞ 0.00 Eccentricity [7]
ASP [1]
Curvature radius 7.89, k 0.0000
a -7.8557 × 10 ^-4 , b 2.1256 × 10 ^-5 , c -1.5582 × 10 ^-6 , d 4.1906 × 10 ^-8
ASP [2]
Radius of curvature -7.08, k 0.0000
a 3.2960 × 10 ^-4 , b 1.0965 × 10 ^-5 , c 5.8519 × 10 ^-7 , d 9.2692 × 10 ^-8
ASP [3]
Curvature radius -5.09, k 0.0000
a -1.5174 × 10 ^-3 , b 5.8085 × 10 ^-5 , c -1.6827 × 10 ^-5 , d 1.3452 × 10 ^-6
ASP [4]
Curvature radius 5.70, k 0.0000
a -2.9815 × 10 ^-3 , b 1.1211 × 10 ^-4 , c -3.8893 × 10 ^-6 , d 5.0634 × 10 ^-8
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
C4 -7.2761 × 10 ^-4 0.0000 -4.1810 × 10 ^-4 -1.2865 × 10 ^-3 -5.5229 × 10 ^-4
-7.5325 × 10 ^-4
C6 -3.6010 × 10 ^-4 0.0000 -2.0911 × 10 ^-4 -6.5292 × 10 ^-4 -2.7621 × 10 ^-4
-3.7969 × 10 ^-4
C8 -1.2874 × 10 ^-5 0.0000 -1.1582 × 10 ^-5 -2.3385 × 10 ^-5 -1.1856 × 10 ^-5
-1.9045 × 10 ^-5
C10 -6.2363 × 10 ^-6 0.0000 -5.7799 × 10 ^-6 -1.2413 × 10 ^-5 -6.6142 × 10 ^-6
-1.2098 × 10 ^{-5
C11 8.5992 × 10 -6 0.0000 -1.2374 ×} 10 -6 1.3026 × 10 -5 4.8420 × 10 -7 -
2.8955 × 10 ^{-6
C13 8.0045 × 10 -6 0.0000 -1.7717 ×} 10 -6 1.2539 × 10 -5 2.4473 × 10 -6 -
2.3267 × 10 ^-6
C15 1.8452 × 10 ^-6 0.0000 -4.6466 × 10 ^-7 2.5536 × 10 ^-6 -3.7355 × 10 ^-7
-1.1379 × 10 ^-6
Eccentric [1]
X 0.00 Y 0.17 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [3]
X 0.00 Y decy Z decz
α 45 β 0.00 γ 0.00
State 1 State 2 State 3 State 4 State 5 State 6
decy 0.005 0 0.004 0.007 0.004 0.006
decz 0.005 0 0.004 0.007 0.004 0.006

Eccentric [4]
X 0.00 Y -0.09 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [5]
X 0.00 Y -0.07 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [6]
X 0.00 Y -0.06 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [7]
X 0.00 Y -0.05 Z 0.00
α -2.16 β 0.00 γ 0.00

  The third embodiment is an example of an imaging device 116 for a digital camera using a variable mirror as shown in FIG.

  This embodiment has substantially the same configuration as that of the second embodiment, but is an optical system capable of focusing up to 150 mm by increasing the decentering of each lens and the tilt of the image sensor. . The zoom ratio is 2.0 times.

Example 4
Object distance Zoom Fno. Focal length state 1 ∞ Wide angle 2.8449 4.22127
State 2 ∞ Standard 3.1912 5.75071
State 3 ∞ Telephoto 3.4907 8.08140
Condition 5 300mm Standard 3.1912 5.75071
Imaging surface size: X 4mm x Y 3mm
Px = Py = 2.5μm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 39.4929 1.0000 1.78472 25.68
2 474.3906 7.2046
3 -42.6405 0.5000 1.88300 40.76
4 ASP [1] 8.0018
5 FFS [1] (DM) -0.0018 Eccentricity [1]
6 999.0000 -0.3000
7 999.0000 -0.2307
8 999.0000 -0.5000
9 999.0000 D1 = -10.3161 to -7.2986 to -3.0040
10 Diaphragm surface -0.0027
11 ASP [2] -1.5000 1.58913 61.14
12 35.8649 -0.3000
13 -5.1025 -1.9963 1.49700 81.54
14 7.2438 -0.2906
15 -8.7222 -1.0482 1.51633 64.14
16 -6.4397 -0.6000
17 8.8339 -0.3631 1.78472 25.68
18 ASP [3] D2 = -0.8526 to -3.8655 to -8.1673
19 -5.6538 -2.0000 1.58913 61.14
20 ASP [4] -0.7069
21 ∞ -1.4 400 1.54771 62.84
22 ∞ -0.1000
23 ∞ -0.6000 1.51633 64.14
24 ∞ -0.1000
Image plane ∞
ASP [1]
Curvature radius 12.5383, k 0
a -3.7625 × 10 ^-4 , b 1.6313 × 10 ^-5 , c -5.6290 × 10 ^-7 , d 6.9835 × 10 ^-9
ASP [2]
Radius of curvature -10.8213, k 0
a 1.3870 × 10 ^-3 , b 3.0924 × 10 ^-5 , c 7.9884 × 10 ^-6 , d -8.1500 × 10 ^-7
ASP [3]
Radius of curvature -3.1489, k 0
a -7.5029 × 10 ^-9 , b -8.0505 × 10 ^-9 , c -1.2342 × 10 ^-5 , d -1.9009 × 10 ^-5
ASP [4]
Curvature radius 4.6193, k 0
a -8.9627 × 10 ^-3 , b 4.0263 × 10 ^-4 , c -1.2792 × 10 ^-5 , d 2.4193 × 10 ^-11
FFS [1]
Radius of curvature ∞, k 0
State 1 State 2 State 3 State 5
C4 -2.7980 × 10 ^-3 -1.0000 × 10 ^-3 -1.4138 × 10 ^-3 -1.7067 × 10 ^-3
C6 -1.2465 × 10 ^-3 -7.0000 × 10 ^-4 -6.7280 × 10 ^-4 -7.8841 × 10 ^-4
C8 -1.2017 × 10 ^-5 0.0000 2.7504 × 10 ^-5 3.1915 × 10 ^-5
C10 -8.9620 × 10 ^-6 0.0000 -1.2445 × 10 ^-5 2.7793 × 10 ^-6
C11 3.7102 × 10 ^-5 0.0000 3.3091 × 10 ^-5 -1.7423 × 10 ^-7
C13 1.9287 × 10 ^-5 0.0000 2.5108 × 10 ^-5 -3.3681 × 10 ^-6
C15 4.3329 × 10 ^-6 0.0000 7.7926 × 10 ^-6 -2.4196 × 10 ^-6
Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α -45.00 β 0.00 γ 0.00

  FIG. 4 shows a sectional view of the fourth embodiment. This is an example of a 2 × zoom lens used in a digital camera, a TV camera, or the like. The origin of the coordinate system is the center of the first surface. Five surfaces are variable mirrors and are concave in all states. The 6th to 9th surfaces are virtual surfaces. After the 6th plane, Z in the coordinate system is reversed. For this reason, the signs of R, D, and aspheric coefficients are opposite to the actual ones.

The variable mirror is deformed while the center of the reflecting surface is fixed, but may be deformed while the periphery of the reflecting surface is fixed.
The optical axis bends 90 degrees at the intersection with the variable mirror. The intersection of the optical axis and the variable mirror is the origin of the surface shape of the variable mirror.

  FIG. 4 shows the directions of the coordinate axes. Note that the directions are different between the first, fourth, fifth and sixth surfaces. As shown in the figure, the imaging surface of the imaging element is inclined for 23 minutes. This is performed in order to obtain the best resolution at the time when the tilt of the image plane changes with the deformation of the variable mirror.

The variable mirror is deformed to compensate for the focus movement that occurs when the lens group is moved and zoomed, and to adjust the focus when the object distance changes.
Surfaces 11 to 18 are variable magnification lenses, which move along the optical axis.

  In this embodiment, the electrostatic drive variable mirror is used, but the deformation of the electrostatic drive variable mirror is limited to the concave side. For this reason, even if the object is at infinity, the shape of the variable mirror in the standard state is not flat. The focus position deviates from the design position due to manufacturing errors such as lens parts, frame parts, and assembly errors. This is because the shape of the lens can be brought close to a plane so that the focus can be adjusted.

  Also, when performing contrast detection (mountain climbing) autofocus, deform the variable mirror to move the focus position, detect the high-frequency component of the subject image, and focus when the high-frequency component of the subject image becomes maximum However, in order to move the focus position further from infinity, it is necessary to make the shape of the variable mirror concave in all states.

(Example 5)
Object distance Zoom Fno. Focal length Diagonal angle of view 1 ∞ Wide angle 3.022 4.801 61.2 °
Condition 2 ∞ Standard 3.411 5.756 49.84 °
State 3 ∞ Telephoto 3.740 6.726 42.2 °
Condition 4 300mm wide angle 3.001 4.801
Condition 5 300mm Standard 3.392 5.756
Condition 6 300mm telephoto 3.721 6.726
Imaging surface size: 4mm x 3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -24.306 1.2 1.71297 31.69
2 ASP [1] 2.2345
3 73.3434 2 1.50461 66.38
4 -70.0057 7.0688
5 FFS [1] (DM) -4.2914 Eccentricity [1]
6 -6.4021 -1.0841 1.71164 50.41
7 -5.1257 -0.3865
8 -5.6419 -2.3267 1.89494 24.58
9 -5.7514 D1 = -4.29597 to -2.53996 to -0.99848
10 Diaphragm surface -0.835
11 ASP [2] -2.0224 1.58913 61.14
12 17.503 -1.0067
13 -6.0673 -2.153 1.497 81.54
14 8.6875 -0.8413
15 14.8278 -1.0216 1.84666 23.78
16 -3.8628 D2 = -1.71739 to -3.47341 to -5.01488
17 -16.9294 -2.0604 1.58913 61.14
18 ASP [3] -1.2241
19 ∞ -1.44 1.54771 62.84
20 ∞ -0.8
21 ∞ -0.6 1.51633 64.14
22 ∞ -0.5
Image plane ∞

ASP [1]
Curvature radius 9.4392, k 0.0000
a -2.0683 × 10 ^-4 , b 1.1006 × 10 ^-6 , c -8.0740 × 10 ^-8 , d 5.4537 × 10 ^-10
ASP [2]
Curvature radius -8.9634, k 0.0000
a 8.1855 × 10 ^-4 , b 2.9005 × 10 ^-5 , c -2.9963 × 10 ^-6 , d 3.7358 × 10 ^-7
ASP [3]
Curvature radius 6.002, k 0.0000
a -1.0905 × 10 ^-3 , b 7.2538 × 10 ^-5 , c -7.1600 × 10 ^-6 , d 3.4177 × 10 ^-7
Eccentric [1]
X 0 Y 0 Z 0
α -45 β 0 γ 0
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
C4 -2.2433 × 10 ^-4 0.0000 -9.3831 × 10 ^-5 -5.0582 × 10 ^-4 -2.6002 × 10 ^-4
-3.8015 × 10 ^-4
C6 -1.1925 × 10 ^-4 0.0000 -5.1098 × 10 ^-5 -2.5619 × 10 ^-4 -1.2941 × 10 ^-4
-1.8895 × 10 ^-4
C8 -2.8598 × 10 ^-6 0.0000 -1.6606 × 10 ^-7 -4.9422 × 10 ^-6 -1.1846 × 10 ^-6
-1.0426 × 10 ^-6
C10 -1.6824 × 10 ^-6 0.0000 -8.8244 × 10 ^-7 -2.9138 × 10 ^-6 -1.4327 × 10 ^-6
-2.9231 × 10 ^-6
C11 6.7042 × 10 ^-6 0.0000 -2.1354 × 10 ^-6 8.3102 × 10 ^-6 1.1080 × 10 ^-6 -5
.1439 × 10 ^-7
C13 6.9240 × 10 ^-6 0.0000 -1.9547 × 10 ^-6 8.3939 × 10 ^-6 8.3965 × 10 ^-7 -8
.9360 × 10 ^-7
C15 1.7668 × 10 ^-6 0.0000 -4.1945 × 10 ^-7 1.9693 × 10 ^-6 1.2489 × 10 ^-7 -3
.5666 × 10 ^-7

  The fifth embodiment is a 1.4 × zoom imaging optical system used for a digital camera, a television camera, or the like as shown in FIG.

  Consists of a concave group 211, a variable mirror 212, a convex group 213, an aperture stop 214, a convex group 215, a convex group 216, an infrared cut filter and a moire removal filter 217, and it becomes a retrofocus type optical system as a whole. ing. The convex group 215 is a variator, and performs zooming by moving in the optical axis direction (z-axis direction in the figure).

  The variable mirror 212 has functions of a compensator and a focusing lens, and is deformed to compensate for a focus position shift caused by zooming and a focus shift caused by a change in object distance. The shape is a plane when the object distance is ∞ and the zoom is in the standard state, and the shape is a free-form surface in other states.

  The concave group 211 has a two-lens configuration including a concave lens 218 and a convex lens 219. This has the effect of alleviating strong negative distortion occurring in the concave lens 218, and also has the effect of lowering the light beam height at the concave lens 218. Further, as a result of the two effects, since the burden of aberration correction of the aspheric lens used in the optical system can be reduced, the amount of the aspheric surface can be relaxed and the manufacturing becomes easier.

  The ray diagram of FIG. 5 is representative when the object distance ∞ and the zoom state are wide angle, standard and telephoto. Further, the coordinate system shown in FIG. 5 is common to each state. Note that different coordinate systems are used on the object side from the variable mirror 212 and on the image plane side from the variable mirror 212 and the variable mirror 212, respectively.

(Example 6)
Object distance Zoom Fno. Focal length Diagonal angle of view 1 ∞ Wide angle 3.980 4.652 57.1 °
Condition 2 ∞ Standard 4.477 5.453 49.2 °
State 3 ∞ Telephoto 5.149 6.701 40.5 °
Condition 4 300mm wide angle 3.961 4.652
Condition 5 300mm Standard 4.459 5.453
Condition 6 300mm telephoto 5.133 6.701
Imaging surface size 4mm x 3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -38.5523 2.045 1.744 44.78
2 ASP [1] 3.1074
3 63.3299 3.3731 1.51633 64.14
4 -55.7768 10.5953
5 FFS [1] (DM) -4.5963 Eccentricity [1]
6 -106.8041 -2.0514 1.92286 18.9
7 -4240.8114 D1 = -6.80213 ~ -4.23488 ~ -0.76948
8 Aperture plane -0.0787
9 ASP [2] -6.2388 1.5725 57.74
10 23.4652 -1.2298
11 -8.3423 -2.3156 1.52249 59.84
12 11.2443 -0.8167
13 10.9717 -1.0734 1.84666 23.78
14 -4.447 D2 = -0.68903 ~ -3.25628 ~ -6.72167
15 -9.0599 -3.7612 1.5725 57.74
16 ASP [3] -1.5817
17 ∞ -1.44 1.54771 62.84
18 ∞ -0.8
19 ∞ -0.6 1.51633 64.14
20 ∞ -0.5
Image plane ∞
ASP [1]
Curvature radius 8.6410, k 0.0000
A -4.5614 × 10 ^-4 , B 2.9660 × 10 ^-6 , C -1.3571 × 10 ^-7 , D 1.5429 × 10 ^-9
ASP [2]
Curvature radius -9.4088, k 0.0000
a 2.6088 × 10 ^-4 , b 5.8088 × 10 ^-6 , c -2.4412 × 10 ^-7 , d 2.0243 × 10 ^-8
ASP [3]
Curvature radius 9.0075, k 0.0000
a -1.3159 × 10 ^-3 , b 6.5552 × 10 ^-5 , c -5.2821 × 10 ^-6 , d 2.0025 × 10 ^-7
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
^{C4 -2.4155 × 10 -4 0.0000 2.7301 ×} 10 -5 -4.2833 × 10 -4 -1.7222 × 10 -4 -
1.5675 × 10 ^-4
C6 -1.1909 × 10 ^-4 0.0000 1.5481 × 10 ^-5 -2.1381 × 10 ^-4 -9.1215 × 10 ^-5-
7.6576 × 10 ^-5
C8 -3.5587 × 10 ^-6 0.0000 3.8957 × 10 ^-8 -2.8029 × 10 ^-6 8.3713 × 10 ^-7 5.
9061 × 10 ^-7
C10 -1.6571 × 10 ^-6 0.0000 -6.1292 × 10 ^-8 -1.8332 × 10 ^-6 -6.6528 × 10 ^-7
-1.6575 × 10 ^{-6
C11 9.5081 × 10 -6 0.0000 -3.0453 ×} 10 -6 8.4450 × 10 -6 -1.5904 × 10 -6 -
4.5466 × 10 ^{-6
C13 8.9905 × 10 -6 0.0000 -3.2328 ×} 10 -6 8.0447 × 10 -6 -1.2389 × 10 -6 -
4.7765 × 10 ^{-6
C15 2.3001 × 10 -6 0.0000 -8.8762 ×} 10 -7 1.9921 × 10 -6 -2.5879 × 10 -7 -
1.2345 × 10 ^-6
Eccentric [1]
X 0 Y 0 Z 0
α -45 β 0 γ 0

  The sixth embodiment is a 1.4 × zoom imaging optical system used for a digital camera, a television camera, or the like as shown in FIG.

  Consists of a concave group 221, a variable mirror 222, a convex group 223, an aperture stop 224, a convex group 225, a convex group 226, an infrared cut filter and a moire removal filter 227, and is a retrofocus type optical system as a whole. ing. The convex group 225 is a variator and performs zooming by moving in the optical axis direction (z-axis direction in the figure).

  The variable mirror 222 has functions of a compensator and a focusing lens, and is deformed to compensate for a focus position shift caused by zooming and a focus shift caused by a change in object distance. The shape is a plane when the object distance is ∞ and the zoom is in the standard state, and the shape is a free-form surface in other states.

In this embodiment, the convex group 223 has a single lens configuration, and the number of lenses is smaller than that of the convex group 213 in the fifth embodiment. Therefore, the cost can be further reduced.
The ray diagram of FIG. 6 is representative when the object distance ∞ and the zoom state are wide angle, standard and telephoto. The coordinate system shown in FIG. 6 is common to each state. However, care is required because different coordinate systems are used on the object side from the variable mirror 222 and on the image plane side from the variable mirror 222 and the variable mirror 222, respectively.

(Example 7)
Object distance Zoom Fno. Focal length Diagonal angle of view 1 ∞ Wide angle 3.416 4.613 57.7 °
Condition 2 ∞ Standard 3.859 5.452 48.8 °
State 3 ∞ Telephoto 4.415 6.703 39.8 °
Condition 4 300mm wide angle 3.393 4.613
Condition 5 300mm standard 3.839 5.452
Condition 6 300mm telephoto 4.394 6.703
Imaging surface size 4mm x 3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -28.7616 1.6339 1.72916 54.68
2 ASP [1] 5.017
3 54.6152 2.9255 1.497 81.54
4 -49.9256 4.5
5 FFS [1] (DM) D1 = -12.1381 to -10.03316 to -7.33504
Eccentric [1]
6 Diaphragm surface -0.1297
7 ASP [2] -5.2993 1.58313 59.38
8 22.9382 -1.1742
9 -6.7237 -2.2996 1.456 90.33
10 9.6725 -0.8548
11 9.7133 -1.0241 1.72151 29.23
12 -3.9774 D2 = -1.10099 ~ -3.20589 ~ -5.90401
13 -11.478 -2.244 1.603 65.44
14 ASP [3] -1.4865
15 ∞ -1.44 1.54771 62.84
16 ∞ -0.8
17 ∞ -0.6 1.51633 64.14
18 ∞ -0.5
Image plane ∞
ASP [1]
Curvature radius 10.0576, k 0.0000
a -4.0835 × 10 ^-4 , b 4.3979 × 10 ^-6 , c -1.5633 × 10 ^-7 , d 1.9974 × 10 ^-9
ASP [2]
Radius of curvature -9.1682, k 0.0000
a 3.4194 × 10 ^-4 , b 2.4869 × 10 ^-9 , c 9.8662 × 10 ^-7 , d -5.8064 × 10 ^-8
ASP [3]
Curvature radius 7.7704, k 0.0000
a -1.5911 × 10 ^-3 , b 8.6440 × 10 ^-5 , c -7.3116 × 10 ^-6 , d 2.9293 × 10 ^-7
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
C4 -3.2829 × 10 ^-4 0.0000 -2.6321 × 10 ^-6 -6.0794 × 10 ^-4 -2.5035 × 10 ^-4
-2.8099 × 10 ^-4
C6 -1.6462 × 10 ^-4 0.0000 -5.8132 × 10 ^-6 -3.0603 × 10 ^-4 -1.2764 × 10 ^-4
-1.4301 × 10 ^-4
C8 -8.0 161 × 10 ^-6 0.0000 1.3356 × 10 ^-6 -5.9070 × 10 ^-6 2.6211 × 10 ^-6 3.
7096 × 10 ^{-6
C10 -3.1928 × 10 -6 0.0000 1.6332 ×} 10 -7 -2.6085 × 10 -6 2.7854 × 10 -7 -
8.1693 × 10 ^{-7
C11 1.1826 × 10 -5 0.0000 -4.6352 ×} 10 -6 1.1156 × 10 -5 -1.8158 × 10 -6 -
6.0249 × 10 ^{-6
C13 1.1056 × 10 -5 0.0000 -4.1022 ×} 10 -6 1.0686 × 10 -5 -1.3540 × 10 -6 -
5.7482 × 10 ^{-6
C15 2.8228 × 10 -6 0.0000 -1.0533 ×} 10 -6 2.5287 × 10 -6 -5.8769 × 10 -7 -
1.5497 × 10 ^-6
Eccentric [1]
X 0 Y 0 Z 0
α -45 β 0 γ 0

  The seventh embodiment is a 1.4 × zoom imaging optical system used for a digital camera, a television camera, or the like as shown in FIG.

  A concave group 231, a variable mirror 232, an aperture stop 233, a convex group 234, a convex group 235, an infrared cut filter and a moire removal filter 236 are configured as a retrofocus type optical system as a whole. The convex group 234 is a variator, and performs zooming by moving in the optical axis direction (z-axis direction in the figure).

  The variable mirror 232 has functions of a compensator and a focusing lens, and is deformed to compensate for a focus position shift caused by zooming and a focus shift caused by a change in object distance. The shape is a plane when the object distance is ∞ and the zoom is in the standard state, and the shape is a free-form surface in other states.

  In the present embodiment, there is no convex group corresponding to the convex group 213 of the fifth embodiment and the convex group 223 of the sixth embodiment. As a result, the number of lenses can be reduced, the cost can be further reduced, and the movement range of the convex group 234 as a variator can be expanded, so that an optical system with a higher zoom ratio can be easily obtained. There is.

  The ray diagram of FIG. 7 is representative when the object distance ∞ and the zoom state are wide angle, standard and telephoto. Further, the coordinate system shown in FIG. 7 is common to each state. However, care is required because different coordinate systems are used on the object side from the variable mirror 232 and on the image plane side from the variable mirror 232 and the variable mirror 232.

(Example 8)
Object distance Zoom Fno. Focal length state 1 ∞ Wide angle 5.0000 9.04749
State 2 ∞ Standard 3.8000 7.01436
State 3 ∞ Telephoto 2.8000 5.08010
Imaging surface size X 4mm × Y 3mm
Px = Py = 5μm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 ∞ 0.0000
2 35.1214 1.0000 1.78472 25.68
3 167.8232 1.0000
4 130.3582 0.2969 1.51633 64.14
5 ASP [1] 18.7302
6 FFS [1] (DM) -4.3019 Eccentricity [1]
7 ∞ 0.0000
8 -7.7555 -2.3000 1.58913 61.14
9 32.1532 (Aperture surface) -0.1123
10 1000.0000 -0.1000
11 1000.0000 D1 = -4.225292 to -2.62378 to -1.01260
12 ∞ -0.7833
13 ASP [2] -0.1000
14 1000.0000 -0.1000
15 5.7308 -0.6694 1.84666 23.78
16 -15.1681 -0.2586
17 1000.0000 -0.1000
18 ASP [3] D2 = 0.204107〜-1.36283〜-2.96276
19 -15.3016 -2.0000 1.69680 55.53
20 13.8966 -0.3000
21 -8.9786 -5.3922 1.58913 61.14
22 ASP [4] -0.6387
23 49.9212 -1.0000 1.51633 64.14
24 -69.5147 -1.1964
25 ∞ -1.4 400 1.54771 62.84
26 ∞ -0.1000
27 ∞ -0.6000 1.51633 64.14
28 ∞ -2.1000
Image plane ∞
ASP [1]
Radius of curvature 11.4689, k 0
a -1.4142 × 10 ^-4 , b 1.4501 × 10 ^-7 , c 1.0445 × 10 ^-8 , d -4.0703 × 10 ^-13
ASP [2]
Curvature radius 1000.0000, k 0
ASP [3]
Curvature radius 1000.0000, k 0
ASP [4]
Curvature radius 11.0623, k 0
a -2.8728 × 10 ^-3 , b 1.4022 × 10 ^-4 , c -3.9838 × 10 ^-6 , d 3.4424 × 10 ^-10
FFS [1]
Radius of curvature ∞, k 0
State 1 State 2 State 3
C4 1.6713 × 10 ^-3 0.0000 -7.2848 × 10 ^-4
C6 1.0083 × 10 ^-3 0.0000 -8.1095 × 10 ^-4
C8 -1.1132 × 10 ^-4 0.0000 3.4637 × 10 ^-5
C10 -1.8948 × 10 ^-5 0.0000 2.3972 × 10 ^-6
C11 8.9426 × 10 ^-5 0.0000 -4.4633 × 10 ^-5
C13 3.1405 × 10 ^-5 0.0000 4.9175 × 10 ^-5
C15 1.8300 × 10 ^-5 0.0000 -9.5845 × 10 ^-6
Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α -45.00 β 0.00 γ 0.00

  FIG. 8 shows a sectional view of the eighth embodiment. This is an example of 1.8 × zoom in which 15 to 16 concave lenses are moved to perform zooming. The six surfaces are variable mirrors that perform focus movement accompanying zooming and focus movement accompanying object distance change by changing the surface shape. By performing zooming with a concave lens, there is a merit that large zooming can be performed with a small amount of lens movement compared to zooming with a convex lens.

Example 9
Object distance Zoom Fno. Focal length state 1 ∞ Telephoto 5.0000 8.15692
State 2 ∞ Standard 3.8000 6.89107
State 3 ∞ Wide angle 2.8000 4.52486
Condition 5 300mm Standard 3.8000 6.89107
Imaging surface size X 4mm × Y 3mm
Px = Py = 5μm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 ∞ 0.0000
2 -303.0641 0.7000 1.51633 64.14
3 9.2736 1.0000
4 20.6261 1.2000 1.78472 25.68
5 ASP [1] 7.0000
6 FFS [1] (DM) -7.2293 Eccentricity [1]
7 ∞ 0.0000
8 -6.7720 -2.3000 1.58913 61.14
9 70.7255 (diaphragm surface) -0.0225
10 ∞ -0.1000
11 ∞ D1 = -2.74171 ~ -1.85566 ~ 0.13614
12 ∞ -0.7833
13 ASP [2] -1.0000 1.69680 55.53
14 189.1667 -0.4000
15 4.6448 -1.2571 1.84666 23.78
16 -22.3831 -0.1403
17 ∞ -0.1000
18 ASP [3] D2 = -0.29533〜-1.23656〜-3.19451
19 -14.4658 -2.0000 1.69680 55.53
20 9.9717 -0.3000
21 -9.2901 -3.5540 1.58913 61.14
22 ASP [4] -0.3626
23 107.3171 -0.8865 1.51633 64.14
24 -291.5336 -0.6489
25 ∞ -1.4 400 1.54771 62.84
26 ∞ -0.1000
27 ∞ -0.6000 1.51633 64.14
28 ∞ -2.1000
Image plane ∞
ASP [1]
Curvature radius 342.4201, k 0
a -9.1895 × 10 ^-5 , b 5.4102 × 10 ^-7 , c -2.4185 × 10 ^-8 , d -2.3500 × 10 ^-11
ASP [2]
Radius of curvature -186.8247, k 0
ASP [3]
Radius of curvature ∞, k 0
ASP [4]
Radius of curvature 9.1729, k 0
a -3.2236 × 10 ^-3 , b 1.6799 × 10 ^-4 , c -5.5687 × 10 ^-6 , d 5.0927 × 10 ^-10
FFS [1]
Radius of curvature ∞, k 0
State 1 State 2 State 3 State 5
C4 2.2386 × 10 ^-3 1.5000 × 10 ^-3 5.5152 × 10 ^-4 4.7137 × 10 ^-4
C6 1.4954 × 10 ^-3 1.0000 × 10 ^-3 3.2716 × 10 ^-4 3.3428 × 10 ^-4
C8 -5.4914 × 10 ^-5 0.0000 -7.2448 × 10 ^-6 2.5619 × 10 ^-5
C10 -8.2461 × 10 ^-7 0.0000 1.7986 × 10 ^-6 6.2461 × 10 ^-6
C11 1.0352 × 10 ^-5 0.0000 1.1053 × 10 ^-7 -2.7914 × 10 ^-5
C13 -3.9167 × 10 ^-5 0.0000 -5.9980 × 10 ^-6 1.2558 × 10 ^-5
C15 -1.2899 × 10 ^-7 0.0000 -3.8539 × 10 ^-7 -1.2580 × 10 ^-5
Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α -45.00 β 0.00 γ 0.00

  FIG. 9 shows a sectional view of the ninth embodiment. This is an example of a 1.8 × zoom lens that changes magnification by moving a concave lens group having 13 to 16 surfaces. The variable magnification lens has a two-concave structure, and realizes improved aberrations.

By making the first and second lenses concave and convex, the distance to the surface of the variable mirror 6 was shortened, and thereby an optical system having a thickness thinner than that of Example 8 could be realized.
The six surfaces are variable mirrors that perform focus movement accompanying zooming and focus movement accompanying object distance change by changing the surface shape. By performing zooming with a concave lens, there is an advantage that a large zooming can be performed with a small amount of lens movement compared to when zooming with a convex lens.

  In addition, although the eighth and ninth embodiments are designed for the concave variable magnification group, in this case, the system of the first group, the deformable mirror, and the second group has a positive power as a whole, and the negative power is changed. It is configured to create imaginary points for double groups. By doing so, it is possible to effectively perform zooming with a zooming group of negative power.

(Example 10)
Object distance Zoom Fno. Focal length state 1 ∞ Telephoto 3.9000 8.23940
State 2 ∞ Standard 3.2000 6.41384
State 3 ∞ Wide angle 2.8000 5.47790
Condition 5 300mm Standard 3.2000 6.41384
Imaging surface size X 4mm × Y 3mm
Px = Py = 2.5μm, k = 2.0

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 ∞ 0.0000
2 -504.0444 0.7000 1.51633 64.14
3 8.6811 1.0000
4 20.3265 1.2000 1.78472 25.68
5 ASP [1] 7.0000
6 FFS [1] (DM) -4.0000 Eccentricity [1]
7 ∞ -2.2293
8 ∞ D1 = 1.20003 to 0.21911 to -0.43913
9 ∞ -1.0000
10 -9.4331 -2.3000 1.58913 61.14
11 222.2495 (diaphragm surface) -1.0000
12 ∞ D2 = -1.20003 to -0.21911 to 0.43913
13 ∞ -0.6475
14 ∞ -1.0000
15 ASP [2] -1.0000 1.69680 55.53
16 2905.0515 -0.4000
17 4.9561 -0.1711 1.84666 23.78
18 -32.876 -0.0972
19 ∞ -0.3953
20 ASP [3] D3 = 1.20003 to 0.21911 to -0.43913
21 ∞ -1.0000
22 -11.9555 -2.0000 1.69680 55.53
23 11.2189 -0.3000
24 -6.4379 -4.2823 1.58913 61.14
25 ASP [4] -1.5598
26 ∞ D4 = -1.20003 to -0.21911 to 0.43913
27 ∞ -0.9296
28 ∞ -1.4 400 1.54771 62.84
29 ∞ -0.1000
30 ∞ -0.6000 1.51633 64.14
31 ∞ -2.1000
Image plane ∞
ASP [1]
Radius of curvature 419.2460, k 0
a -9.4595 × 10 ^-5 , b 7.2229 × 10 ^-7 , c -2.5763 × 10 ^-8 , d -1.0490 × 10 ^-10
ASP [2]
Radius of curvature -1848.9723, k 0
ASP [3]
Radius of curvature ∞, k 0
ASP [4]
Curvature radius 23.0340, k 0
a -2.5469 × 10 ^-3 , b 3.9717 × 10 ^-5 , c -4.6619 × 10 ^-6 , d 1.1907 × 10 ^-8
FFS [1]
Radius of curvature ∞, k 0
State 1 State 2 State 3 State 5
C4 2.2824 × 10 ^-3 1.5000 × 10 ^-3 1.9335 × 10 ^-4 1.1794 × 10 ^-3
C6 1.0312 × 10 ^-3 1.0000 × 10 ^-3 1.0345 × 10 ^-4 6.0055 × 10 ^-4
C8 9.4653 × 10 ^-6 0.0000 7.2377 × 10 ^-6 -2.1271 × 10 ^-5
C10 -1.2969 × 10 ^-5 0.0000 2.2733 × 10 ^-7 -6.3319 × 10 ^-6
C11 -2.6948 × 10 ^-5 0.0000 -4.0076 × 10 ^-6 -6.459 × 10 ^-6
C13 7.0776 × 10 ^-6 0.0000 -5.7967 × 10 ^-7 5.0297 × 10 ^-6
C15 -1.0268 × 10 ^-6 0.0000 -9.5026 × 10 ^-7 -2.6466 × 10 ^-6
Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α -45.00 β 0.00 γ 0.00

  FIG. 10 shows a sectional view of the tenth embodiment. 2 groups (10 to 11 surfaces) and 4 groups (22 to 25 surfaces) before and after the 3 groups from the 15th surface to the 18th surface are always moved by the same movement amount for zooming. That is, it can be considered that the second group and the fourth group are mechanically integrated. The second group and the fourth group have the same code power, and the third group has a different power code. That is, if the third group is negative power, the second and fourth groups are positive power. If the third group is positive power, the second and fourth groups are negative power.

  For applications that require that the chief ray emitted from the imaging optical system is telecentric, such as a solid-state imaging device, it is preferable that the third group has a negative power and the second and fourth groups have a positive power. This is because if the fourth group has positive power, the chief rays can be easily telecentric. This type of zoom lens is similar to what is called an optically corrected zoom, but in this embodiment, the focus movement accompanying the movement of the lens group and the focus movement accompanying the object distance change are corrected by the variable mirror. is doing. Of course, either one may be corrected.

  Since the two lens groups move in the same way, no cam is required, the cost is low, and if the power distribution is selected, there is little focus movement at the time of zooming, and there is an advantage that the deformation amount of the variable mirror can be reduced.

Group 3 may move. Although the variable mirror is arranged between the first group and the second group, it may be arranged after the fourth group or the like.
In this type of optical system, a variator refers to a group having the highest ratio of change in magnification among optical element groups that move during zooming. In Example 10, there are 4 groups. Group 4 changes from -0.976 times to -0.78 times from the telephoto end to the wide-angle end, while Group 2 changes from -0.325 times to -0.314 times from the telephoto end to the wide-angle end. Therefore, the definition of the fourth group may be the variator itself in addition to the above definition.

  The conditional expressions described so far are also applied to this type of optical system, but for the expressions 324 to 329, the variator refers to a lens group that is close to a variable mirror among the lens groups that move during zooming. .

As can be said for all of the present invention, an optical element group is a block composed of one or more optical elements.
The following conditional expression should be satisfied.

0.3 <| f2 / f | <10 Expression 340
Here, f2 is the focal length of the front optical element group among the moving optical element groups.

When | f2 / f | is less than the lower limit, the aberration increases. Or 0.6 <| f2 / f | <5 Expression 341
And that's even better.

1.1 <| f2 / f | <5 Expression 341-2
Even better.
Moreover, it is preferable to satisfy the following conditional expression.

0.15 <| f3 / f | <6 Expression 342
Here, f3 is the focal length of the optical element group sandwiched between the moving optical element groups.

  When | f3 / f | is below the lower limit, the aberration increases, and when it exceeds the upper limit, the zooming action combined with the moving optical element group or the action as a compensator is insufficient.

0.25 <| f3 / f | <3 Expression 343
And that's even better.
0.35 <| f3 / f | <2.2 Formula 343-2
Even better.

Moreover, it is preferable to satisfy the following conditional expression.
0.15 <| f4 / f | <7 Expression 344
Here, f4 is the focal length of the rear optical element group among the moving optical element groups.

  When | f4 / f | is below the lower limit, the aberration increases. When | f4 / f | is higher than the upper limit, the zooming function or the function as a compensator is insufficient.

0.25 <| f4 / f | <3 Expression 344-2
And that's even better.
0.4 <| f4 / f | <2 Equation 345
Even better. Expressions 340 to 345 may be applied to other embodiments of the present invention as long as there is no problem.

(Example 11)
Object distance Zoom Fno. Focal length state 1 ∞ Telephoto 4.5000 8.74026
State 2 ∞ Standard 3.2000 6.42951
State 3 ∞ Wide angle 2.8000 4.79958
Condition 5 300mm Standard 3.2000 6.42951
Imaging surface size X 4mm × Y 3mm
Px = Py = 2.5 μm, k = 2.1

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 ∞ 0.0000
2 -964.7304 0.7000 1.51633 64.14
3 9.5889 1.0000
4 17.7453 1.2000 1.78472 25.68
5 ASP [1] 7.0000
6 FFS [1] (DM) -4.0000 Eccentricity [1]
7 ∞ -0.5000
8 ∞ D1 = 1.68135 ~ 0.59966 ~ -0.57528
9 ∞ -1.0000
10 -10.4257 -1.3000 1.58913 61.14
11 388.0611 -1.0000
12 ∞ D2 = -1.68135 to -0.59966 to 0.57528
13 ∞ 0.0000
14 Diaphragm surface -1.0000
15 ASP [2] -1.0000 1.69680 55.53
16 14410 -0.4000
17 4.1865 -0.1711 1.84666 23.78
18 -34.6352 -0.0967
19 ∞ -1.3953
20 ASP [3] D3 = 1.68135 ~ 0.59966 ~ -0.57528
21 ∞ -1.0000
22 -15.1800 -2.0000 1.69680 55.53
23 9.5514 -0.3000
24 -6.4630 -4.8432 1.58913 61.14
25 ASP [4] -1.2137
26 ∞ D4 = -1.68135 to -0.59966 to 0.57528
27 ∞ -0.7234
28 ∞ -1.4 400 1.54771 62.84
29 ∞ -0.1000
30 ∞ -0.6000 1.51633 64.14
31 ∞ -2.1000
Image plane ∞
ASP [1]
Curvature radius 559.6254, k 0
a -1.1630 × 10 ^-4 , b 8.6486 × 10 ^-7 , c -1.4621 × 10 ^-8 , d -1.0484 × 10 ^-10
ASP [2]
Radius of curvature -9397.6126, k 0
ASP [3]
Radius of curvature ∞, k 0
ASP [4]
Curvature radius 16.8496, k 0
a -3.0683 × 10 ^-3 , b 7.9412 × 10 ^-5 , c -6.1481 × 10 ^-6 , d 7.1383 × 10 ^-10
FFS [1]
Radius of curvature ∞, k 0
State 1 State 2 State 3 State 5
C4 -5.0000 × 10 ^-4 -6.2241 × 10 ^-4 -5.0000 × 10 ^-3 -1.7652 × 10 ^-3
C6 -1.5288 × 10 ^-4 -3.4826 × 10 ^-4 -2.2850 × 10 ^-3 -8.0538 × 10 ^-4
C8 2.1605 × 10 ^-5 4.2421 × 10 ^-11 5.9732 × 10 ^-5 4.6464 × 10 ^-5
C10 -1.4053 × 10 ^-6 3.0300 × 10 ^-12 4.4807 × 10 ^-5 1.5296 × 10 ^-5
C11 2.7287 × 10 ^-6 2.1366 × 10 ^-10 3.8387 × 10 ^-5 8.945 × 10 ^-6
C13 9.4480 × 10 ^-7 7.2849 × 10 ^-11 2.0863 × 10 ^-5 9.2071 × 10 ^-6
C15 -1.5247 × 10 ^-6 9.1322 × 10 ^-12 1.6418 × 10 ^-6 -1.7323 × 10 ^-6
Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α -45.00 β 0.00 γ 0.00

  FIG. 11 shows a cross-sectional view of the eleventh embodiment. This embodiment has the same type as that of the tenth embodiment. The diaphragm is fixed in the vicinity of a fixed group of concave power. For this reason, there is an advantage that there is little fluctuation of the light beam height at the time of zooming.

Each conditional expression is satisfied similarly to the tenth embodiment.
The variable mirror is concave in all shooting states, and is designed to be suitable for an electrostatically driven variable mirror. Of the shape of the variable mirror, the range from the flat surface to the concave surface in the photographing state is a margin for contrast-type autofocus. That is, it corresponds to P2Q in FIG.

  Similarly, for autofocusing at the near point, the variable mirror is deformed into a deeper concave surface than the shape of the variable mirror at the near point 300 mm. In other words, it is a margin for autofocus at near points. This corresponds to RR2 in FIG.

As can be said in common with the present invention, in the case of a zoom lens having a relatively narrow angle of view, the expression 316 may be replaced by the following expression 347.
f1 / f <0 or f1 / f> 5 Formula 347
This is because when the angle of view is narrow, the light beam height in the optical system can be kept low even if it is not a retrofocus type.

(Example 12)
Object distance Zoom Fno. Focal length state 1 ∞ Telephoto 4.5000 8.73317
State 2 ∞ Standard 3.2000 6.27299
State 3 ∞ Wide angle 2.8000 4.29905
Condition 5 300mm Standard 3.2000 6.27299
Imaging surface size X 4mm × Y 3mm
Px = Py = 2.5 μm, k = 2.5

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 ∞ 0.0000
2 -482.8203 0.7000 1.51633 64.14
3 6.3094 1.0000
4 27.9840 1.2000 1.78472 25.68
5 ASP [1] 5.0000
6 FFS [1] (DM) -4.0000 Eccentricity [1]
7 ∞ -0.5000
8 ∞ D1 = 2.93012 ~ 1.71055 ~ 0.01162
9 ∞ -1.0000
10 -9.1491 -1.3000 1.58913 61.14
11 1065.1375 -1.0000
12 ∞ D2 = -2.93012 ~ -1.71055 ~ -0.01162
13 ∞ 0.5000
14 Diaphragm surface -1.0000
15 ASP [2] -1.0000 1.69680 55.53
16 290 700 -0.4000
17 5.8684 -0.1711 1.84666 23.78
18 -80.3252 -0.2000
19 ∞ -1.8953
20 ASP [3] D3 = 2.93012 ~ 1.71055 ~ 0.01162
21 ∞ -1.0000
22 -15.1465 -2.0000 1.69680 55.53
23 10.5668 -0.3000
24 -8.2373 -4.3398 1.58913 61.14
25 ASP [4] -2.0230
26 ∞ D4 = -2.93012 ~ -1.71055 ~ -0.01162
27 ∞ -1.2057
28 ∞ -1.4 400 1.54771 62.84
29 ∞ -0.1000
30 ∞ -0.6000 1.51633 64.14
31 ∞ -2.1000
Image plane ∞
ASP [1]
Radius of curvature 322.8961, k 0
a -1.8286 × 10 ^-4 , b -4.7666 × 10 ^-6 , c -3.6610 × 10 ^-8 , d -1.0357 × 10 ^-9
ASP [2]
Curvature radius -125 200, k 0
ASP [3]
Radius of curvature ∞, k 0
ASP [4]
Curvature radius 53.5355, k 0
a -2.0411 × 10 ^-3 , b 1.8960 × 10 ^-4 , c -2.1343 × 10 ^-5 , d 7.5729 × 10 ^-7
FFS [1]
Radius of curvature ∞, k 0
State 1 State 2 State 3 State 5
C4 -1.0000 × 10 ^-3 8.0649 × 10 ^-4 -1.0000 × 10 ^-3 2.6458 × 10 ^-4
C6 -3.8000 × 10 ^-4 4.0553 × 10 ^-4 -3.5320 × 10 ^-4 1.0179 × 10 ^-4
C8 -6.5634 × 10 ^-7 9.6342 × 10 ^-6 8.1981 × 10 ^-6 8.9472 × 10 ^-6
C10 -3.2350 × 10 ^-6 6.8916 × 10 ^-6 1.4590 × 10 ^-5 3.6633 × 10 ^-6
C11 -8.6083 × 10 ^-6 -2.7438 × 10 ^-5 3.6593 × 10 ^-6 -2.4821 × 10 ^-5
C13 -9.4944 × 10 ^-6 -9.8705 × 10 ^-6 -1.0661 × 10 ^-6 -9.8971 × 10 ^-7
C15 -8.2680 × 10 ^-6 -8.2617 × 10 ^-6 -1.2234 × 10 ^-5 -6.6129 × 10 ^-6
Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α -45.00 β 0.00 γ 0.00

  FIG. 12 shows a sectional view of the twelfth embodiment. This example is also of the same type as the tenth and eleventh embodiments, but is designed to be deformed to both concave and convex sides in order to reduce the deformation amount of the variable mirror.

  In addition, the negative power of the first group is increased and the wide angle is set. The distance from the variable mirror to the first lens is small, suitable for small digital cameras and card-type digital cameras.

(Example 13)
Object distance Zoom Focal length Diagonal angle of view 1 ∞ Wide angle 4.2 61.53 °
State 2 ∞ Standard 6.3 43.29 °
State 3 ∞ Telephoto 8.4 33.15 °
State 4 300mm Wide angle state 5 300mm Standard state 6 300mm Telephoto
Fno .: 2.82 to 3.52
Imaging surface size: 4.4mm x 3.3mm

Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ (Object distance)
1 -14.36 1.00 Eccentricity [1] 1.7291 45.7
2 ASP [1] 6.45 Eccentricity [1]
3 ∞ 0.00
4 FFS [1] (DM) 0.00 Eccentricity [3]
5 ∞ -3.80
6 -7.65 -2.19 1.6831 31.6
7 -6.02 -0.14
8 -8.31 -2.00 1.7453 41.7
9 -16.30 D1 = -7.11 to -3.37 to -0.12
10 Diaphragm surface -0.10
11 ASP [2] -2.69 Eccentricity [4] 1.5821 62.5
12 -31.78 -1.38 Eccentricity [4]
13 -5.27 -2.44 Eccentricity [5] 1.4875 70.4
14 6.74 -0.96 Eccentric [5]
15 4.81 -0.80 Eccentricity [6] 1.7551 27.6
16 ASP [3] D2 = -0.58 ~ -4.32 ~ -7.57
Eccentric [6]
17 -9.41 -2.61 1.6001 61.4
18 6.52 -0.20
19 5.89 -1.54 1.7444 43.9
20 ASP [4] -0.10
21 ∞ -1.44 1.5477 62.8
22 ∞ -0.80
23 ∞ -0.60 1.5163 64.1
24 ∞ -0.50
Image plane ∞ 0.00 Eccentricity [7]
ASP [1]
Curvature radius 9.74, k 0.0000
a -6.2519 × 10 ^-4 , b 1.2541 × 10 ^-5 , c -7.6432 × 10 ^-7 , d 1.7319 × 10 ^-8
ASP [2]
Radius of curvature -6.60, k 0.0000
a 4.2068 × 10 ^-4 , b 2.6754 × 10 ^-5 , c -3.3993 × 10 ^-6 , d 5.4375 × 10 ^-7
ASP [3]
Radius of curvature -5.34, k 0.0000
a -1.4669 × 10 ^-3 , b -2.5868 × 10 ^-5 , c 2.4908 × 10 ^-5 , d -3.9721 × 10 ^-6
ASP [4]
Curvature radius 5.62, k 0.0000
a -2.9782 × 10 ^-3 , b 1.2391 × 10 ^-4 , c -4.8542 × 10 ^-6 , d 7.6341 × 10 ^-8
FFS [1]
State 1 State 2 State 3 State 4 State 5 State 6
C4 -7.5312 × 10 ^-4 0.0000 -3.4212 × 10 ^-4 -1.0695 × 10 ^-3 -3.0806 × 10 ^-4
-6.5191 × 10 ^-4
C6 -3.7728 × 10 ^-4 0.0000 -1.7218 × 10 ^-4 -5.4546 × 10 ^-4 -1.5079 × 10 ^-4
-3.2651 × 10 ^-4
C8 -1.3987 × 10 ^-5 0.0000 -7.6019 × 10 ^-6 -1.5925 × 10 ^-5 -6.6752 × 10 ^-6
-1.7035 × 10 ^-5
C10 -5.6901 × 10 ^-6 0.0000 -3.6267 × 10 ^-6 -8.3321 × 10 ^-6 -2.9455 × 10 ^-6
-7.9035 × 10 ^-6
C11 1.0628 × 10 ^-5 0.0000 9.5627 × 10 ^-7 1.4199 × 10 ^-5 1.1005 × 10 ^-6 4.
3390 × 10 ^-7
C13 1.0528 × 10 ^-5 0.0000 8.5460 × 10 ^-7 1.3836 × 10 ^-5 2.1106 × 10 ^-6 1.
0298 × 10 ^{-6
C15 2.4609 × 10 -6 0.0000 2.2087 ×} 10 -7 2.9930 × 10 -6 -5.0391 × 10 -8 -
1.4066 × 10 ^-7
Eccentric [1]
X 0.00 Y 0.10 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [3]
X 0.00 Y decy Z decz
α 45 β 0.00 γ 0.00
State 1 State 2 State 3 State 4 State 5 State 6
decy 0.009 0 0 0.008 0.002 0.001
decz 0.009 0 0 0.008 0.002 0.001
Eccentric [4]
X 0.00 Y -0.02 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [5]
X 0.00 Y -0.01 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [6]
X 0.00 Y 0.00 Z 0.00
α 0.00 β 0.00 γ 0.00
Eccentric [7]
X 0.00 Y 0.00 Z 0.00
α -1.86 β 0.00 γ 0.00

  The thirteenth embodiment is an example of an imaging apparatus 101 for a digital camera using a variable mirror as shown in FIG.

  This embodiment has substantially the same configuration as the second and third embodiments described above in that the lens and the image sensor are decentered, but is perpendicular to the mirror reflection surface when the deformable mirror is deformed. Parallel movement of the entire variable mirror in the direction is also performed at the same time. This suppresses decentration aberrations generated by the variable mirror.

  In this embodiment, the entire variable mirror is also translated in parallel with the deformation of the surface of the variable mirror during zooming and focusing. As a result, aberrations that cannot be corrected only by deformation of the mirror surface can be suppressed within an appropriate range.

When the maximum parallel movement amount of the entire variable mirror is x and the focal length of the optical system is f,
0 <| x | / f <1
It is desirable to satisfy. When the upper limit is exceeded, it is difficult to secure a space for moving the mirror in parallel. In addition, it becomes difficult to make the optical system compact.

  As is common to the present invention, in the case of a zoom optical system, it is sufficient that each conditional expression of the present invention satisfies the conditional expression in at least one zoom state. In the case of a zoom optical system, if the variable power group has positive power, the lens configuration can easily be a retrofocus type, and the wide angle can be easily increased. If the zooming group has negative power, a large zooming may be realized with a small movement amount of the zooming group.

Finally, the definition of the coordinate system in each embodiment will be described.
(Examples 1-3, 13)
A z-axis is a straight line that exits the center of the object and is perpendicular to the object plane. The traveling direction of light incident on the optical system is the positive direction of the Z-axis, the plane that includes the Z-axis and the center of the image plane is the YZ plane, passes through the origin, is orthogonal to the YZ plane, and the back side from the front of the page The direction toward the X axis is the X axis positive direction, and the X axis, the Z axis, and the axis constituting the right-handed orthogonal coordinate system are the Y axis.

In these embodiments, each surface is decentered in the 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 a 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 decentered is the k plane.

  For eccentric surfaces, from the origin of the corresponding coordinate system, the amount of eccentricity of the surface top position (X-axis direction, Y-axis direction, and Z-axis direction are X, Y, and Z, respectively) and the center axis of that surface ( For free-form surfaces, inclination angles (α, β, γ (°), respectively) about the X axis, the Y axis, and the Z axis of the equation (a) are given. In this case, the signs of α and β are positive counterclockwise with respect to the positive directions of the X axis and Y axis, respectively, and the sign of γ is positive with respect to the positive direction of the Z axis.

  Eccentricity is done by decenter and return. That is, when the k plane is decentered, the surface top position of the (k + 1) plane is a point moved by the surface interval in the Z-axis direction from the surface top position of the k plane before decentering.

  The order of eccentricity is that the surface apex position of the surface is decentered by X, Y, Z in the X-axis direction, Y-axis direction, and Z-axis direction, respectively, and then the rotation angles α, Y around the X-axis of the surface Tilt is performed in the order of rotation angle β around the axis and rotation angle γ around the Z axis.

  The expression of the eccentricity of the reflecting surface is as follows. Since all decentering is performed in the YZ plane, the rotation angle of the reflecting surface can be expressed only by the rotation angle α about the X axis. β and γ are always 0. Then, when the reflecting surface is rotated by α, 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 being rotated by 2α. At this time, care should be taken because the traveling direction of the axial principal ray and the positive Z-axis direction of the optical system are reversed before and after reflection.

Regarding the sign of the deformation of the mirror surface, when the mirror surface is deformed into a free-form surface, when the power components C4 and C6 are positive, the mirror surface is a convex mirror. In other words, it becomes a mirror with negative power. On the contrary, when C4 and C6 which are power components are negative, it becomes a concave mirror. In other words, it becomes a mirror with positive power.
(Examples 4 to 12)
The signs α, β, and γ are the same as described above except that the clockwise direction is positive with respect to the positive directions of the X axis, the Y axis, and the Z axis, respectively.

In the above description, an optical system using a variable mirror has been described. However, even when a normal mirror (the shape does not change) is used in place of the variable mirror, the above-described conditional expressions and restrictions may be applied as long as there is no particular problem. This is because the merit of miniaturization of the bending optical system using the mirror is maintained as it is. Moreover, since the power of the variable mirror is weak, it is technically easy to replace it with a normal mirror.
The zoom optical system according to the present invention as described above can be applied to a film camera, a digital camera, a television camera, a camera for a mobile terminal, a surveillance camera, a robot eye, an electronic endoscope, and the like.

  In the zoom optical system described above, the zoom optical system having a reflection surface in the lens group has been described. However, an optical element having a deformable surface also in a zoom optical system having a reflection surface, for example, By using a variable focus lens or the like, it is possible to achieve effects such as downsizing, cost reduction, power saving, and quiet operation noise. Further, a variable focus mirror having no variable shape surface may be used in the above embodiment. An example of the variable focus mirror will be described later with reference to FIG.

Next, a configuration example of a deformable mirror applicable to the optical system or the imaging apparatus of the present invention will be described.
FIG. 19 is a schematic configuration diagram of a Kepler finder of a digital camera using a variable optical property mirror as a variable mirror applicable to the zoom optical system of the present invention. The configuration of this example 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 variable resistors 412 are connected to 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 used to control resistance values of the plurality of variable resistors 411. , 415, 416 and 417 are a temperature sensor, a humidity sensor and a distance sensor respectively connected to the arithmetic device 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 Michrolitho Graphy, Michromachinin G and Michrofabrication, Volume 2: Michromachinin G and Michrofabrication, P495, FiG.8.58, published by SPIE PRESS, Volume 140 When a voltage is applied between the plurality of electrodes 409b as in the membrane mirror described in ˜190, 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 imaging performance due to assembly errors of parts such as optical elements and frames are suppressed, and the focus adjustment is always performed properly. Correction of aberrations caused by cement 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. 21, FIG.
According to this example, 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 transmitted by the isosceles right angle prism 405. Further reflected (in FIG. 19, the + mark in the optical path 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. ing. Thus, the lenses 901, 902, the prisms 404, 405, and the deformable mirror 409 constitute the observation optical system of the optical device of this example, and the surface shape and thickness of each of these optical elements are optimal. 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 deforming the deformable mirror so that the eyes of the observer are in focus.

  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. Note that the prism 404 and the deformable mirror 409 can be integrally formed to form a unit. Although not shown, the solid-state imaging device 408 may be integrally formed on the substrate 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 this example, the lenses 901 and 902 are formed away from the prism 404. However, the prisms 404 and 405, the mirror 406, and the like can be removed without providing the lenses 901 and 902. If the deformable mirror 409 is designed, the prisms 404 and 405 and the deformable mirror 409 become one optical block, and assembly becomes easy. 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.

  In the example of FIG. 19, 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. 20 is a schematic configuration diagram showing another example of a deformable mirror 409 applicable as a deformable mirror used in the zoom optical system of the present invention.
In the deformable mirror of this example, a piezoelectric element 409c is interposed between a thin film 409a and an electrode 409b, and these are provided on a support base 423. 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. 21, a rectangular division as shown in FIG. 22, or any other appropriate shape.

  In FIG. 20, reference numeral 424 denotes a shake (blur) 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 due to 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 considered at the same time, 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. 23 is a schematic configuration diagram showing still another example of a deformable mirror 409 applicable as a deformable mirror used in the zoom optical system of the present invention. The deformable mirror of this example is composed of two piezoelectric elements 409c and 409c ′ in which a piezoelectric element interposed between the thin film 409a and the 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 the material 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 PbZrO3 and PbTiO3, organic piezoelectric materials such as polyvinyl difluoride (PVDF), ferroelectrics other than the above, especially organic piezoelectric materials Is preferable because it has a small Young's modulus and can be deformed greatly even at a low voltage. Note that when these piezoelectric elements are used, the shape of the thin film 409a can be appropriately deformed in the above example if the thickness is made non-uniform.

  The piezoelectric elements 409c and 409c ′ may be made of a piezoelectric material such as polyurethane, silicone rubber, acrylic elastomer, PZT, PLZT, polyvinylidene fluoride (PVDF), vinylidene cyanide copolymer, vinylidene fluoride and tri-vinyl chloride. 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.

  20 and 24, 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. 24 is a schematic configuration diagram showing still another example of a deformable mirror 409 applicable as a deformable mirror used in the zoom optical system of the present invention.
In the deformable mirror of this example, 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 example, the thin film 409a can be deformed doubly by the voltage applied between the electrode 409d and the electrostatic force by the voltage applied to the electrode 409b, more than any of those shown in the above example. Many deformation patterns are possible and there is an advantage that the response 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 the piezoelectric effect, and a minute shape change may be performed by 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 invention, 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. 25 is a schematic configuration diagram showing still another example of a deformable mirror 409 applicable as a deformable mirror used in the zoom optical system of the present invention.
The deformable mirror of this example 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 or 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. 26, the winding density of the thin film coil 427 can be changed depending on the location, whereby desired deformation can be applied to the substrate 409e and the thin film 409a. One coil 427 may be provided, and an iron core made of a ferromagnetic material may be inserted into these coils 427.

FIG. 27 is a schematic configuration diagram showing still another example of a deformable mirror 409 applicable as a deformable mirror used in the zoom optical system of the present invention.
In the deformable mirror of this example, 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. Further, 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. 28 shows the arrangement of the coil 427 in this example, and FIG. 29 shows another arrangement example of the coil 427, but these arrangements can also be applied to the embodiment shown in FIG. FIG. 30 shows the arrangement of permanent magnets 426 that is suitable when the coil 427 is arranged as shown in FIG. 33 in the example shown in FIG. That is, if the permanent magnets 426 are arranged radially as shown in FIG. 30, it is possible to give a subtle deformation to the substrate 409e and the thin film 409a compared to the example shown in FIG. Further, when the substrate 409e and the thin film 409a are deformed by using electromagnetic force in this way (examples of FIGS. 25 and 27), there is an advantage that they can be driven at a lower voltage than when electrostatic force is used.

  Although several examples 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.

  Also, the outer shape of the deformable part of the deformable mirror is preferably long in the direction parallel to the incident surface of the axial light beam, and if configured in this way, it has a shape close to an elliptical surface advantageous for aberration correction. There is an advantage that it is easy to deform. As a shape that is long in the direction parallel to the incident surface, a track shape, a polygon, an ellipse, or the like can be used.

  FIG. 31 shows an imaging system using a deformable mirror 409 as a deformable mirror applicable to an imaging apparatus using the zoom optical system of the present invention, such as a digital camera of a mobile phone, a capsule endoscope, an electronic endoscope, a personal computer 1 is a schematic configuration diagram of an imaging system used for a digital camera for a digital camera, a digital camera for a PDA, and the like.

  In the imaging system of this example, 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 example, the light from the object that has passed through the lens 102 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 example, even if the object distance changes, it is possible to focus by deforming the deformable mirror 409, and there is no need to drive the lens with a motor or the like, and the size, weight and power consumption are reduced. Is excellent in terms of. 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. 31 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.

  FIG. 32 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 example applicable as a deformable mirror used in the zoom optical system of the present invention. According to this example, 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. 33 is a schematic configuration diagram showing an example of a micropump applicable to the variable shape mirror used in the zoom optical system of the present invention. In the micropump 180 of this example, the vibration plate 181 vibrates by an electric force such as an electrostatic force or a piezoelectric effect. FIG. 33 shows an example in which vibration is caused by electrostatic force. In FIG. 33, 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 example, 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 that case, for example, as shown in FIG. 31, a 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. 34 shows a variable focus mirror using a variable focus lens, which can be applied to the zoom optical system of 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. 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, and an AC electric field is applied to the polymer dispersed liquid crystal layer 514. Is applied. In FIG. 34, liquid crystal molecules are not shown. It has a structure in which a variable focus lens made up of 513a, 514 and 513b and a concave mirror made up of 567 and 568 are combined.

  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 shape 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 present invention, a variable focus mirror whose shape does not change as shown in FIG. 34 is also included in the variable shape mirror.

  FIG. 35 is a schematic configuration diagram showing still another example of a deformable mirror applicable as a deformable mirror used in the zoom optical system of the present invention. In this example, it is assumed that it is used for a digital camera. In FIG. 35, 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 example 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 provided on the electrostrictive material 453 in order. Further, a reflective 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. 35, 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.
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.

Since the optical system of the present invention is small and light, it is effective when used in an electronic imaging device, a signal processing device, particularly a digital camera or a mobile phone imaging system.
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, or a surface having non-differentiable points or lines 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 imaging apparatus or optical system according to the present invention has the following features, for example.
(1) A zoom optical system having a variable mirror and a moving optical element group, the optical element group having a zooming function, and the variable mirror having a focusing function.
(2) The zoom optical system according to (1), wherein the moving optical element group has negative power.
(3) In an image pickup apparatus that performs a hill-climbing autofocus with a variable mirror, in addition to the amount of deformation QR of the variable mirror required for focusing, the focus is at least 1/3 of Sd determined by the following expression 370 An imaging device having a variable mirror that has deformation amounts necessary to change the angle at both ends of the QR.

Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is.
(4) A zoom optical system having a variable mirror and a moving optical element group, the optical element group having a zooming function, and the variable mirror having a focusing function and a compensator function.
(5) The first optical element group, a variable mirror or variable focus lens disposed behind the first optical element group, and a variable magnification optical element group disposed behind the first optical element group, according to (1) to (4) Zoom optical system.
(6) The first optical element group, the variable mirror or the variable focus lens, the second optical element group or the air gap, the variable magnification optical element group, and the optical element group in order from the front to (1) to (5) The zoom optical system described.
(7) An imaging optical system characterized in that during zooming or focusing, the variable mirror is deformed and the entire variable mirror is translated in a direction substantially perpendicular to the mirror reflection surface.
(8) An imaging optical system characterized in that, during zooming or focusing, the entire variable mirror is translated in a certain direction along with the deformation of the variable mirror.
(9) When the maximum parallel movement amount of the entire variable mirror is x and the focal length of the optical system is f,
0 <| x | / f <1
An imaging optical system characterized by satisfying the above.
(10) The imaging optical system according to (9) subordinate to (7) or (8).
(11) The imaging optical system according to any one of (1) to (10), wherein there is one moving lens group.
(12) A variable mirror is provided, and the two optical element groups before and after a certain optical element group always move with the same movement amount for zooming, and the two moving groups have the same sign power, and A zoom optical system in which the power of the group sandwiched between the moving groups is opposite, and the variable mirror has a focus function or a compensator function.
(13) The zoom optical system according to (12), wherein the powers of the two moving groups are positive.
(14) The zoom optical system according to (12), wherein the powers of the two moving groups are negative.
(15) The zoom optical system according to (12), which includes a group having negative power in order from the front, a variable mirror, a front of the moving group, a group sandwiched between the moving groups, and a rear of the moving group.
(16) A zoom optical system having a variable mirror and a variable power group having a variable power function, wherein the variable mirror has a focusing function, and the variable mirror is disposed in front of the variable power group.
(17) A variable mirror and a moving optical element group, and the optical element group is a zooming group having a zooming function. The variable mirror has a focusing function and a compensator function, and is variable in front of the zooming group. A zoom optical system comprising a mirror.
(18) The zoom optical system according to any one of (16) to (17) subordinate to (7) to (15).
(19) The zoom optical system according to any one of (1) to (18), which includes a rotationally symmetric lens and a variable mirror.
(20) The zoom optical system according to any one of (1) to (18), which includes a rotationally symmetric lens and a variable mirror.
(21) The zoom optical system according to any one of (1) to (20), wherein Expressions 301 to 304 are satisfied.
(22) The zoom optical system according to any one of (1) to (20), wherein Expressions 305 to 309 are satisfied.
(23) The zoom optical system according to any one of (1) to (20), which satisfies expressions 311 to 314.
(24) The zoom optical system according to any one of (1) to (20), wherein Expressions 316 to 321 are satisfied.
(25) The zoom optical system according to any one of (1) to (20), wherein Expressions 322 to 323 are satisfied.
(26) The zoom optical system according to any one of (1) to (20), wherein Expressions 324 to 326 are satisfied.
(27) The zoom optical system according to any one of (1) to (20), wherein Expressions 327 to 329 are satisfied.
(28) The zoom optical system according to any one of (1) to (20), wherein Expressions 330 to 333 are satisfied.
(29) The zoom optical system according to any one of (1) to (20), wherein Expressions 335 to 336 are satisfied.
(30) The zoom optical system according to any one of (1) to (20), wherein Expressions 340 to 347 are satisfied.
(31) The zoom optical system according to any one of (1) to (20), wherein at least two of Expressions 301 to 347 are satisfied.
(32) The zoom optical system according to (1) to (20), wherein at least one of expressions 340 to 347 and at least one of expressions 301 to 336 are satisfied.
(33) The zoom optical system according to any one of (1) to (29), wherein the aperture stop is located behind the variable mirror.
(34) The zoom optical system according to any one of (1) to (16), wherein the moving optical element group has positive power.
(34 ′) The zoom optical system according to any one of (1) to (16), wherein the moving optical element group has negative power.
(35) An image pickup apparatus having a variable mirror driven by static electricity, wherein the shape of the variable mirror is concave within the range of the object distance to be imaged at the time of shooting.
(36) In an imaging apparatus having a hill-climbing type autofocus that changes a focus on an object, detects a high-frequency component of a captured object image, and determines that the in-focus state when the high-frequency component becomes maximum, The imaging device according to (35).
(37) An imaging apparatus including a state in which the shape of the variable mirror is flat when changing the focus with respect to the object when performing autofocus in (36).
(38) In an image pickup apparatus that performs auto-focusing of a mountain climbing method having a variable mirror, it is necessary to change the focus by at least Sd determined by Expression 370 in addition to the deformation amount QR of the variable mirror required for focusing. Imaging device with a variable mirror that has a large amount of deformation at both ends of the QR.
(39) In an image pickup apparatus that performs a hill-climbing autofocus with a zoom optical system with a variable mirror, in addition to the amount of deformation QR of the variable mirror required as a focus and a compensator, Sd determined by at least Expression 370 An imaging device that has a variable mirror that has the deformation amount necessary to change the focus at both ends of the QR.
(40) In an imaging apparatus that performs a mountain climbing type autofocus with a zoom optical system with a variable mirror, in addition to the variable mirror deformation amount QR necessary as a focus and a compensator, at least Sd determined by Expression 370 An image pickup apparatus having a variable mirror that has a deformation amount necessary to change the focus by 1/3 of both ends of the QR.
(41) The imaging device according to any one of (3) and (38) to (40) having the characteristics described in (35).
(42) An imaging apparatus that includes a variable mirror and performs active autofocus.
(43) An electronic imaging apparatus that includes a variable mirror and an imaging element and performs active autofocus.
(44) The imaging device according to (35) to (43) including the optical system according to (1) to (34 ′).
(45) An imaging device that satisfies Expression 102.
(46) An image pickup apparatus including the optical system according to any one of (1) to (34 ′), including an image pickup element, wherein the positional relationship between the optical element closest to the object and the image pickup element is fixed.
(47) The imaging apparatus according to (44), further including an imaging element, wherein the positional relationship between the optical element closest to the object and the imaging element is fixed.
(48) The optical system or the imaging device according to any one of (1) to (47), wherein a normal mirror is used instead of the variable mirror.
(49) The optical system or the imaging apparatus according to any one of (1) to (47), wherein a variable focus lens is used instead of the variable mirror.

It is sectional drawing of Example 1 of this invention. It is sectional drawing of Example 2 of this invention. It is sectional drawing of Example 3 of this invention. It is sectional drawing of Example 4 of this invention. It is sectional drawing of Example 5 of this invention. It is sectional drawing of Example 6 of this invention. It is sectional drawing of Example 7 of this invention. It is sectional drawing of Example 8 of this invention. It is sectional drawing of Example 9 of this invention. It is sectional drawing of Example 10 of this invention. It is sectional drawing of Example 11 of this invention. It is sectional drawing of Example 12 of this invention. It is sectional drawing of Example 13 of this invention. It is explanatory drawing of a rotationally asymmetric field curvature. It is explanatory drawing of a rotationally asymmetric astigmatism. It is explanatory drawing of a rotationally asymmetric coma aberration. It is a figure which shows the deformation | transformation amount of a variable mirror, and operation | movement of an imaging system. It is a table | surface which shows the value of the conditional expression of each Example. It is a schematic block diagram of a Kepler type finder of a digital camera using an optical property variable mirror as a shape variable mirror applicable to the present invention. It is a schematic block diagram which shows the other example of the deformable mirror 409 applicable as a deformable mirror used for 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 applicable as a deformable mirror used for this invention. It is a schematic block diagram which shows the further another example of the deformable mirror 409 applicable as a deformable mirror used for this invention. It is a schematic block diagram which shows the further another example of the deformable mirror 409 applicable as a deformable mirror used for 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 applicable as a deformable mirror used for the zoom optical system of this invention. It is explanatory drawing which shows the example of 1 arrangement | positioning of the coil 427 in the example of FIG. It is explanatory drawing which shows the other example of arrangement | positioning of the coil 427 in the example of FIG. In the example shown in FIG. 25, it is explanatory drawing which shows arrangement | positioning of the permanent magnet 426 suitable when the coil 427 is arrange | positioned like FIG. It is a schematic block diagram of the imaging system using the deformable mirror 409 as a deformable mirror applicable to the imaging device using the zoom optical system of the present invention. It is a schematic block diagram of the variable shape mirror 188 of the further another example applicable as a variable shape mirror used for this invention. It is a schematic block diagram which shows an example of the micropump applicable to the variable shape mirror used for this invention. It is a figure which shows the variable focus mirror which applied a variable focus lens applicable to this invention. It is a schematic block diagram which shows the further another example of the deformable mirror applicable to the deformable mirror used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Imaging device 101 1st lens group 102 Variable mirror 103 2nd lens group 104 3rd lens group 105 4th lens group 106 Parallel plate 107 Solid-state image sensor

Claims (6)

In an imaging device that performs auto-focusing of a mountain climbing method with a variable focus lens,
The deformation amount QR of the variable focus lens is deformed within a deformation range obtained by adding at least a predetermined deformation amount to both ends of the deformation range necessary for focusing,
The predetermined deformation amount is a deformation amount required to change the focus by one third of Sd determined by equation 370 below
The imaging apparatus as described above .
Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is. In an imaging device that performs auto-focusing on a mountain climbing system with a variable mirror,
The deformation amount QR of the variable mirror is deformed in a deformation range obtained by adding at least a predetermined deformation amount to both ends of the deformation range necessary for focusing,
The predetermined deformation amount is a deformation amount required to change the focus by one third of Sd determined by equation 370 below
The imaging apparatus as described above .
Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is. In an imaging apparatus that performs auto-focusing of a mountain climbing method having an optical element with variable optical characteristics,
The deformation amount QR of the optical property variable optical element is deformed in a deformation range obtained by adding at least a predetermined deformation amount to both ends of a deformation range necessary for focusing,
The predetermined deformation amount is a deformation amount required to change the focus by one third of Sd determined by equation 370 below
The imaging apparatus as described above .
Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is. In an imaging apparatus that performs auto-focusing of a mountain climbing system having a zoom optical system having a variable focus lens,
The deformation amount QR of the variable focus lens is deformed in a deformation range obtained by adding at least a predetermined deformation amount to both ends of a deformation range necessary for focusing and compensator,
The predetermined deformation amount is a deformation amount required to change the focus by one third of Sd determined by equation 370 below
The imaging apparatus as described above .
Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is. In an imaging apparatus that performs auto-focusing of a mountain climbing method having a zoom optical system having a variable mirror
The deformation amount QR of the variable mirror is deformed within a deformation range obtained by adding at least a predetermined deformation amount to both ends of a deformation range necessary for focusing and compensator,
The predetermined deformation amount is a deformation amount required to change the focus by one third of Sd determined by equation 370 below
The imaging apparatus as described above .
Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is. In an image pickup apparatus that performs auto-focusing of a mountain climbing method having a zoom optical system having a variable optical property optical element,
The deformation amount QR of the optical property variable optical element is deformed in a deformation range obtained by adding at least a predetermined deformation amount to both ends of a deformation range necessary for focusing and compensator,
The predetermined deformation amount is a deformation amount required to change the focus by one third of Sd determined by equation 370 below
The imaging apparatus as described above .
Sd = k × P × Fno Expression 370
However,
P = √ (Px · Py)
Px: Dimension in the x direction of one pixel of the image sensor Py: Dimension in the y direction of one pixel of the image sensor Fno: F number of the photographing optical system k: Constant (takes a value between 2 and 3)
It is.

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