JP2017219645A - Imaging optical system and imaging apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging optical system capable of easily temperature-compensating of refraction index even when a resin lens is used for correcting color aberration in a telephoto lens while reducing the size of entire system, and an imaging apparatus having the same.SOLUTION: The imaging optical system has an aperture diaphragm, and at least one lens LA that satisfies Δθ×φ<0 at 20 degrees Celsius at the image side of the aperture diaphragm; and at the image side of the aperture diaphragm, at least one lens LB which has a symbol of focus distance different from that of the lens LA. With this, the abnormality partial dispersion ratio of the lens LA, the power of the lens LA, and the power of the lens LB are properly adjusted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photographing optical system and an image pickup apparatus having the same, and is suitable for, for example, a video camera using a solid-state image pickup device, a digital still camera, a TV camera, a surveillance camera, a film camera using a silver salt film, and the like. It is.

  As a long focal length photographing optical system, a so-called telephoto photographing optical system (telephoto lens) comprising a front lens group having a positive refractive power and a rear lens group having a negative refractive power in order from the object side to the image side. )It has been known. Here, the long focal length means, for example, a long focal length compared to the size of the effective imaging range. In general, in a telephoto lens having a long focal length, a chromatic aberration such as an axial chromatic aberration and a lateral chromatic aberration among the various aberrations increases as the focal length increases.

  These chromatic aberrations are corrected by combining a positive lens using a low-dispersion material with anomalous partial dispersion such as fluorite and the trade name S-FPL51 (made by OHARA) and a negative lens using a high-dispersion material. Various telephoto lenses (which have been achromatic) have been proposed.

  Patent Document 1 discloses a telephoto lens having a focal length of 294 mm to 588 mm and a large aperture ratio of about F number 2.88 to 4.08. In Patent Document 2, in a telephoto lens, lateral chromatic aberration is favorably corrected by using an optical element made of a material having a large abnormal partial dispersion ratio in the rear lens group. Patent Document 3 discloses an optical system that uses an organic material having a large anomalous partial dispersion ratio and corrects chromatic aberration satisfactorily while taking into consideration the temperature dependence of the refractive index.

  In many photographic lenses (optical systems), focusing from an object at infinity to an object at a short distance is performed by moving the entire photographic lens or by moving a part of a lens group of the photographic lens. Among these, in the case of a telephoto lens having a long focal length, the entire lens becomes large and heavy, and it is mechanically difficult to focus by moving the entire telephoto lens.

  For this reason, conventionally, many telephoto lenses focus by moving some lens groups. Among these, an inner focus type is used in which focusing is performed by moving a part of a lens group in the central portion of a relatively small and lightweight optical system other than the front lens group. Each of the telephoto lenses disclosed in Patent Documents 1 to 3 includes, in order from the object side, a first lens group having a positive refractive power and a second lens group having a negative refractive power, and the second lens group is placed on the optical axis. Focusing is performed by moving to the image plane side.

JP-A-8-327897 JP 2009-139543 A JP 2009-271166 A

  In general, in the telephoto lens, the entire lens system becomes larger as the focal length is increased. For this reason, in the telephoto lens, it is important to reduce the size of the entire lens system, and particularly to correct chromatic aberration well among various aberrations generated by increasing the focal length. Furthermore, it is important to perform focusing quickly with a small and light lens group other than the front lens group and with less burden on the driving device.

  In general, in a telephoto lens, the front lens group having a positive refractive power becomes larger as the focal length becomes longer. For this reason, in the telephoto lens, it is important to set the lens configuration of the front lens unit having a positive refractive power appropriately to correct the chromatic aberration and obtain high optical performance while reducing the size of the entire system. It becomes. If the lens configuration of the front lens group is inappropriate, the entire system becomes large, various aberrations increase, and it becomes very difficult to obtain high optical performance.

  However, if an attempt is made to reduce the size beyond a certain total length, the chromatic aberration cannot be corrected with the front lens group alone and remains. Specifically, it becomes difficult to correct both axial chromatic aberration and lateral chromatic aberration with only the front lens group, and either one remains.

  For this reason, it is known that Patent Document 2 should be used to correct both axial chromatic aberration and lateral chromatic aberration satisfactorily. Specifically, axial chromatic aberration and lateral chromatic aberration are corrected with a positive lens made of a material having a large abnormal partial dispersion ratio such as fluorite in the front lens group. Then, it is preferable to correct lateral chromatic aberration by disposing an optical element made of a resin material having a high dispersion and a large abnormal partial dispersion ratio with a negative power in the lens group on the image side of the aperture stop.

  However, in order to reduce the size of the telephoto lens (shortening the total length), if it is configured as in Patent Document 2, it is necessary to apply very large power to the optical element made of the resin material. For this reason, deterioration in imaging performance caused by a change in refractive index due to temperature cannot be ignored.

  Further, as described in Patent Document 3, if optical elements made of a plurality of resin materials including optical elements made of a resin material having a large abnormal partial dispersion ratio are used in combination with powers of different signs, chromatic aberration correction and the optical Temperature compensation of the refractive index of the element is possible.

  However, in order to reduce the size of the telephoto lens (shortening the total length), it is necessary to apply a very large power to the optical element made of the resin material as described above. Therefore, in the temperature compensation technique disclosed in Patent Document 3, It was insufficient and further improvement was necessary.

  The present invention provides an imaging optical system that can easily compensate for the refractive index temperature even when a resin lens is used to correct chromatic aberration in a telephoto lens, and that can reduce the size of the entire system, and an imaging apparatus having the same. For the purpose.

In order to achieve the above object, a photographing optical system according to the present invention includes:
An aperture stop is provided, and at 20 degrees Celsius, at least one lens LA satisfying conditional expression (1) is provided on the image side of the aperture stop. Similarly, the lens LA has a focal length on the image side of the aperture stop. At least one lens LB having a different sign, and at 20 degrees Celsius, the anomalous partial dispersion ratio of the lens LA is Δθ _gFA , the power of the lens LA is φ _A , the power of the lens LB is φ _B , and when focusing at infinity When the power of the whole system is φ,
Δθ _gFA × φ _A <0 (1)
0.0272 <│Δθ _gFA │ <0.3000 (2)

It satisfies the following condition.

  According to the present invention, there is provided a photographing optical system and an image pickup apparatus having the same, in which the temperature compensation of the refractive index is easy even when a resin lens is used for correcting chromatic aberration in the telephoto lens, and the entire system can be downsized. can get.

(A), (B), (C), (D) Lens cross-sectional view and aberration diagram at each environmental temperature of the photographing optical system of Example 1 of the present invention when the object distance is infinite. (A), (B), (C), (D) Lens cross-sectional view and aberration diagram at each environmental temperature of the photographing optical system of Example 2 of the present invention when the object distance is infinite. (A), (B), (C), (D) Lens cross-sectional view and aberration diagram at each environmental temperature of the photographing optical system of Example 3 of the present invention at an object distance of infinity. (A), (B), (C), (D) Lens cross-sectional view and aberration diagram at each environmental temperature of the photographing optical system of Example 4 of the present invention when the object distance is infinite. Explanatory drawing of the imaging device of the present invention The figure explaining the range of conditional expression (2) which concerns on this invention The figure explaining the range of conditional expressions (7)-(10) concerning the present invention Graph showing refractive index change by wavelength of general glass material Schematic diagram of paraxial arrangement for explaining optical action of photographing optical system of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The photographic optical system L0 of each embodiment is composed of a telephoto lens, and the characteristic configuration thereof is as follows.

Each embodiment has an aperture stop, and at 20 degrees Celsius, has at least one lens LA that satisfies the conditional expression (1) on the image side of the aperture stop, and also has a lens LA on the image side of the aperture stop. _Has at least one lens LB with a different focal length sign, and at 20 degrees Celsius, the anomalous partial dispersion ratio of the lens LA is Δθ _gFA , the power of the lens LA is φ _A , the power of the lens LB is φ _B , and infinite When the power of the entire system at the distance is φ,
Δθ _gFA × φ _A <0 (1)
0.0272 <│Δθ _gFA │ <0.3000 (2)

Is satisfied. However, the Abbe number ν _dA and the partial dispersion ratio difference Δθ _gFA are N _dA for the refractive index of the material constituting the optical element A, N _gA for the refractive index for the g line, and N _CA for the refractive index for the C line. If the refractive index at the F-line is N _FA , it is defined by the following equation.

_{ν dA = (N dA -1)} / (N FA -N CA)
_{θ gFA = (N gA -N FA} ) / (N FA -N CA)
θ _gF0 = -1.665 × 10 ^-7 × ν _dA ³ + 5.213 × 10 ^-5 × ν _dA ² −5.656 × 10 ^-3 × ν _dA +0.7278
Δθ _gFA = θ _gFA −θ _gF0
The photographing optical system of the present invention includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power moving in the optical axis direction for focusing, and a positive or negative lens in order from the object side to the image side. A third lens unit having a refractive power is included. FIG. 9 is a schematic diagram of the paraxial refractive power arrangement of the photographing optical system L0. FIG. 9 shows a paraxial refractive power arrangement for explaining the optical action in the reference state (infinite object focusing state) when rear focusing (inner focusing) is assumed in the photographing optical system L0.

  In the figure, L1 is a first lens group having a positive refractive power, and L2 is a second lens group having a negative refractive power that moves in the optical axis direction for focusing. L3 is a third lens group having positive or negative refractive power, but details are omitted in this figure. LX is the optical axis. IP is the image plane. P is the axial paraxial ray, and Q is the pupil paraxial ray. SP is an aperture stop.

  In general, in the telephoto lens, the incident height of the axial paraxial ray P to the lens is higher on the object side than the point SPX (ideal aperture stop position) where the optical axis LX and the pupil paraxial ray Q intersect, and the image It is lower on the side. Thus, the telephoto lens has a so-called telephoto type (telephoto type) configuration.

  At this time, if the overall length is shortened in a telephoto lens having a long focal length f and a small F number Fno (a ratio of the focal length f and the F number Fno−), the following problems arise. Here, the telephoto lens indicates, for example, a lens having a focal length f = 600 mm, an F number Fno = 4.0, a focal length f = 800 mm, and an F number Fno = 5.6.

  If the power of the first lens group is increased while correcting the chromatic aberration by using fluorite or a diffractive optical element for the first lens group, and the total lens length is shortened to a certain extent, the longitudinal chromatic aberration and the lateral chromatic aberration are reduced. The correction balance is lost. For example, if the axial chromatic aberration is sufficiently corrected, the lateral chromatic aberration is insufficiently corrected. In particular, the lateral chromatic aberration between the g line and the F line cannot be sufficiently corrected.

  Some chromatic aberration is allowed if the image quality is equivalent to that of a normal full high-definition display (number of pixels: 1920 × 1080, pixel size: several μm). However, considering higher image quality by increasing the number of pixels or reducing the pixel size, it is necessary to sufficiently correct axial chromatic aberration and lateral chromatic aberration.

  Therefore, in each embodiment, the following is performed.

  At least one lens LA and one lens LB are arranged on the image side from the aperture stop SP. The sign of power is opposite between the lens LA and the lens LB. The lens LA satisfies conditional expressions (1) to (3), and the relationship between the power of the lens LA and the lens LB satisfies the conditional expression (4). Thus, the chromatic aberration of magnification between the g-line and the F-line is corrected while performing temperature compensation between the lens LA and the lens LB.

  First, the mechanism of chromatic aberration correction at this time will be described.

  In the photographing optical system L0 as shown in the paraxial refractive power arrangement model of FIG. 9, the axial paraxial ray P is incident on the lens surface on the object side from the position SPX where the pupil paraxial ray Q intersects the optical axis LX. Since it passes through a high position from the axis LX, more axial chromatic aberration occurs than the lens on the image plane side. Further, the more the pupil paraxial ray Q goes from the position SPX where it intersects the optical axis LX to the object side (or image side), the more the off-axis principal ray passes through the peripheral portion of the lens, and the more chromatic aberration of magnification occurs.

  Therefore, an optical element for correcting chromatic aberration such as a lens or a diffractive optical element made of a material having anomalous dispersion characteristics is arranged on the object side (particularly the first lens group) from the position SPX where the pupil paraxial ray Q intersects the optical axis LX. By doing so, both axial chromatic aberration and lateral chromatic aberration can be corrected. By doing so, it is possible to perform chromatic aberration correction between the C line and the F line and axial chromatic aberration correction between the g line and the F line for the longitudinal chromatic aberration and the lateral chromatic aberration, respectively.

  However, if the power of the first lens group is increased in order to shorten the total lens length, the amount of chromatic aberration particularly between the g-line and the F-line increases. This is because, as shown in FIG. 8, a general optical material used for a lens differs in size due to a difference in dispersion, but the change in refractive index increases as the wavelength becomes shorter. In general, the positive lens in the first lens group has a large anomalous dispersion in an attempt to correct the chromatic aberration between the C-line and F-line and the g-line and F-line in both axial chromatic aberration and lateral chromatic aberration in a balanced manner. A lot of materials are used.

  If the power of the first lens group is further increased, the contribution ratio of correction of axial chromatic aberration and lateral chromatic aberration differs. Therefore, axial chromatic aberration and lateral chromatic aberration only with the glass material or diffractive optical element arranged in the first lens group. In both cases, it is difficult to correct chromatic aberrations of four wavelengths d, g, C, and F. In particular, if the axial chromatic aberration is sufficiently corrected, the lateral chromatic aberration between the g-line and the F-line becomes insufficiently corrected.

  Therefore, at least one lens LA that satisfies the conditional expressions (1), (2), and (3) is arranged on the image side from the aperture stop SP (the technical meaning of the conditional expression will be described later). As a result, the chromatic aberration is satisfactorily corrected as a whole system by correcting the lateral chromatic aberration between the g-line and the F-line while reducing the influence on the longitudinal chromatic aberration. In each embodiment, in this way, a photographic optical system capable of obtaining a small and high-quality image as a whole is configured.

  Next, the temperature compensation mechanism at this time will be described.

  Substances generally expand as the temperature rises and contract as they fall. Similarly, the optical material expands and contracts. This also changes the refractive index. Specifically, when the temperature rises and expands, the refractive index decreases, and conversely when it contracts, the refractive index increases. When this condition is applied to a lens, in the case of a positive lens, the power increases as the refractive index increases, and the power decreases as the refractive index decreases. The same applies to the negative lens. One of the effects of this phenomenon on the optical system is a change in the imaging position.

  Normally, it is sufficient to move the focus lens group and adjust the focus again. However, there are cases where the focusing mechanism cannot be moved any further at both ends (infinite end or near end). If the lens material is made entirely of glass material, the refractive index change due to temperature is an order of magnitude smaller than that of the resin, so there is a little margin to handle minute refractive index changes at both ends of the focusing mechanism. All you need to do is design with a certain amount.

  However, when a material having a very large refractive index change due to temperature, such as a resin material, is used as a lens, a very large margin must be considered, and the mechanism becomes large.

  In view of this, the present invention has a configuration in which the temperature change of the refractive index can be canceled by a plurality of lenses, and can be realized without increasing the size of the mechanism even if there is a temperature change. Specifically, at least one lens LB satisfying conditional expression (4) is arranged on the image side from the aperture stop SP. By doing so, even if the power of the lens LA or the lens LB changes due to the change in the refractive index of the lens LA and the lens LB due to the temperature change, the change amount can be canceled.

  Next, the technical meaning of each conditional expression described above will be described.

  Conditional expression (1) relates to the power of the lens LA of the photographing optical system L0 and the abnormal partial dispersion ratio of the material constituting the lens LA. Exceeding the upper limit of conditional expression (1) means that the power of the lens LA and the abnormal partial dispersion ratio of the material constituting the lens LA have the same sign. Then, the lateral chromatic aberration between the g line and the F line increases, which is not preferable. In order to solve the problem, the signs of the power of the lens LA and the abnormal partial dispersion ratio of the material constituting the lens LA need to be different.

  Conditional expression (2) relates to the anomalous partial dispersion ratio of the material constituting the lens LA. The range indicated by the conditional expression is shown in FIG. If the upper limit of conditional expression (2) is exceeded, there is an advantage that magnification chromatic aberration between g-line and F-line can be corrected by a minute power, but the sensitivity of the relationship between power and magnification chromatic aberration correction amount becomes high. Therefore, it is not preferable because the production becomes difficult. If the lower limit value of conditional expression (2) is exceeded, the power required to correct the lateral chromatic aberration between the g-line and the F-line increases, and it becomes difficult to correct aberrations other than the lateral chromatic aberration. It is not preferable. Conditional expression (2) is more preferably set as follows.

0.0350 <│Δθ _gFA │ <0.2600 (2a)
The conditional expression (2a) is more preferably set as follows.

0.0400 <│Δθ _gFA │ <0.2500 (2b)
A specific example of a material (hereinafter, also referred to as “optical material”) that constitutes the lens LA that satisfies the conditional expression (2) is, for example, a resin. Among various resins, UV curable resin (Nd = 1.635, νd = 22.7, θgF = 0.69) and N-polyvinylcarbazole (Nd = 1.696, νd = 17.7, θgF = 0. 69) is an optical material satisfying conditional expression (2). The resin is not limited to these as long as it satisfies the conditional expression (2).

As an optical material having characteristics different from those of general glass materials, there is a mixture in which the following inorganic oxide nanoparticles (inorganic particles) are dispersed in a synthetic resin (transparent medium). Examples of the inorganic oxide include TiO ₂ (Nd = 2.304, νd = 13.8), Nb ₂ O ₅ (Nd = 2.367, νd = 14.0). Further, ITO (Indium Tin Oxide) (Nd = 1.8571, νd = 5.68), Cr ₂ O ₃ (Nd = 2.2178, νd = 13.4), BaTiO ₃ (Nd = 2.4362, νd = 11.3).

Among these inorganic oxides, when TiO ₂ (Nd = 2.304, νd = 13.8, θgF = 0.87) fine particles are dispersed in a synthetic resin at an appropriate volume ratio, the above conditional expression ( An optical material satisfying 2) is obtained.

TiO ₂ is a material used in various applications, and in the optical field, it is used as a vapor deposition material that constitutes an optical thin film such as an antireflection film. In addition, photocatalysts, white pigments, and the like, and TiO ₂ fine particles are used as cosmetic materials. In the case where ITO fine particles (Nd = 1.8571, νd = 5.68, θgF = 0.29) are dispersed in the synthetic resin at an appropriate volume ratio among the inorganic oxides, the conditional expression (2 ) Is obtained. ITO is generally known as a material constituting a transparent electrode, and is usually used for an infrared shielding element and an ultraviolet shielding element for other purposes such as a liquid crystal display element and an EL element.

In each example, the average diameter of the TiO ₂ fine particles and ITO fine particles dispersed in the synthetic resin is preferably about 2 nm to 50 nm in consideration of the influence of scattering and the like, and a dispersant or the like may be added to suppress aggregation. The synthetic resin material in which TiO ₂ or ITO is dispersed is preferably a polymer, and high mass productivity can be obtained by photopolymerization molding or thermal polymerization molding using a mold or the like.

  The synthetic resin has an optical constant characteristic such as a synthetic resin having a relatively large partial dispersion ratio or a synthetic resin having a relatively small Abbe number, or a synthetic resin satisfying both of them. N-polyvinylcarbazole, styrene, polymethacrylate Acid methyl (acrylic), etc. can be applied. In examples described later, a UV curable resin is used as a synthetic resin in which these fine particles are dispersed. However, the present invention is not limited to this.

The dispersion characteristic N (λ) of the mixture in which the nanoparticles are dispersed can be easily calculated by the following equation derived from the well-known Drude equation. That is, the refractive index N (λ) at the wavelength λ is
N (λ) = [1 + V {N _M ² (λ) -1} + (1-V) {N _P ² (λ) -1}] ^1/2 (A)
It is. Here, lambda is an arbitrary wavelength, N _M is TiO ₂ or ITO refractive index of the refractive index of the N _P synthetic resin, V is a fraction of the total volume of the TiO ₂ fine particles and ITO fine particles for synthetic resin volume.

However, the resin material generally has a larger refractive index change with temperature than the glass material. When the absolute value of the average value of the refractive index change with respect to the d-line with respect to the temperature change in the temperature range of 0 ° C. to 40 ° C. of the resin material is represented by |
│dn / dT│ ＞ 5.0 × 10 ^-5 (B)
Meet.

  When such a resin is used as the material of the lens LA, it is necessary to dispose the lens so that a change in refractive index due to temperature is canceled by the lens LB described later. By doing so, it is possible to reduce the deterioration of the imaging characteristics due to the refractive index change caused by the surrounding temperature change. The parameters of the conditional expressions described below are all numerical values based on 20 degrees Celsius.

Conditional expression (3) relates to the power of the lens LA (the sum of power when there are a plurality of lenses LA). If the upper limit value of conditional expression (3) is exceeded, the absolute value of the power of the lens LA is too large. Then, the lateral chromatic aberration between the g-line and the F-line is overcorrected, and the correction balance of the lateral chromatic aberration at each wavelength of the g-line, F-line, and C-line is not preferable. If the lower limit of conditional expression (3) is exceeded, the absolute value of the power of the lens LA is too small. This is not preferable because the lateral chromatic aberration between the g-line and the F-line becomes insufficiently corrected and chromatic aberration remains. Conditional expression (3) is more preferably set as follows.

The conditional expression (3a) is more preferably set as follows.

Conditional expression (4) relates to the power of the lens LA (total power when there are a plurality of lenses LA) and the power of the lens LB (total power when there are a plurality of lenses LB). If the upper limit (or lower limit) of conditional expression (4) is exceeded, the power of the lens LA and the power of the lens LB will be biased. Then, the power change of each lens caused by the refractive index change of the lens LA and the lens LB caused by the surrounding temperature change cannot be canceled and remains. In such a case, the change in the position of the imaging plane and the aberration become large, and the imaging performance deteriorates. Conditional expression (4) is more preferably set as follows.

The conditional expression (4a) is more preferably set as follows.

  With the configuration as described above, the photographic optical system that is the object of the present invention is achieved, but it is more preferable that at least one of the following conditions is satisfied. The effect of shortening the overall length and high optical performance can be easily obtained.

  The imaging optical system has a first lens unit L1 that is fixed and has positive refractive power on the most object side during focusing, and is movable and has negative refractive power on the image side than the first lens unit L1 when focusing. It has two lens units L2, and has an aperture stop SP closer to the image side than the first lens unit L1. It is preferable that the combined refractive power of the lens located on the object side with the aperture stop SP as a boundary is positive.

  Alternatively, the first lens unit L1 that has a positive refractive power that is fixed at the time of focusing on the most object side is provided. The paraxial axis ray P on the object side from the point SPX where the optical axis LX and the pupil paraxial ray Q cross each other is closer to the optical axis LX and the pupil than the maximum value from the optical axis LX passing through the lens surface. It is preferable that the maximum value from the optical axis at which the paraxial axial ray P on the image side passes through the lens surface is smaller than the point where the axial rays Q intersect.

  By adopting such a configuration, it is easy to shorten the overall length while maintaining the imaging performance, and it is possible to reduce the lens diameter of the lens for performing focusing. Further, by arranging the aperture stop SP on the image side of the first lens unit L1 having a positive refractive power, the aperture stop diameter can be reduced, so that the aperture unit can also be reduced in size.

  The materials constituting the lens LA and the lens LB are preferably resin materials. As long as the resin material is used, a material having a large abnormal partial dispersion ratio as described later can be used, so that it is possible to easily correct lateral chromatic aberration (particularly lateral chromatic aberration between g-line and F-line).

Further, the distance on the optical axis from the aperture stop SP to the object side vertex of the lens arranged at a position close to the aperture stop SP among the lens LA and the lens LB is d _SL , and the aperture stop SP the distance along the optical axis between the surface apex of the image side of the most image side disposed in that lens in the photographic optical system L0 and L _SP. (Although optical member glass block or the like, not optically have power shall not be considered as a lens.) The refractive index of the d-line based material constituting the lens LA and Abbe number N _A, ν _A, The refractive index and Abbe number based on the d-line of the material constituting the lens LB are N _B and ν _B.

The average value of the d-line reference Abbe numbers of the materials constituting the lens LA when there are a plurality of the lenses LA is ν _A0 (when there is only one lens LA, ν _A0 = ν _A ). An average value of d-line reference Abbe numbers of materials constituting the lens LB when there are a plurality of the lenses LB is ν _B0 (when there is only one lens LB, ν _B0 = ν _B ).
The power of the first lens unit L1 of the photographing optical system L0 is φ ₁ , the power of the entire system at the time of focusing at infinity in the photographing optical system L0 is φ, and the most object at the time of focusing at infinity in the photographing optical system L0 Let L be the distance on the optical axis from the apex of the object side lens surface of the lens on the side to the imaging plane. _Let the anomalous partial dispersion ratio of the lens LA be Δθ _gFA and the power of the lens LA be φ _A.

At this time, one or more of the following conditional expressions should be satisfied.
0.40 <d _SL / L _SP <0.97 (5)
│ν _A0 −ν _B0 │ <15 (6)
10 <ν _A <40 (7)
10 <ν _B <40 (8)
^{_{2.800 × 10 -8 × ν A 4}} -7.710 × 10 -5 × ν A 3 + 6.740 × 10 -4 × ν A 2 -2.392 × 10 -2 × ν A +1.750 <N A <3.451 × 10 - ⁸ × ν _A ⁴ -1.088 × 10 ^-5 × ν _A ³ + 1.247 × 10 ^-3 × ν _A ² -6.350 × 10 ^-2 × ν _A +2.707
... (9)
^{_{2.800 × 10 -8 × ν B 4}} -7.710 × 10 -5 × ν B 3 + 6.740 × 10 -4 × ν B 2 -2.392 × 10 -2 × ν B +1.750 <N B <3.451 × 10 - ⁸ × ν _B ⁴ -1.088 × 10 ^-5 × ν _B ³ + 1.247 × 10 ^-3 × ν _B ² -6.350 × 10 ^-2 × ν _B +2.707
... (10)

Here, Σ represents the sum, n represents the number of the lenses LA, and i is a number given in order from the object side when there are a plurality of the lenses LA. The radius of curvature of the lens surface on the object side of the lens LA is R _1A , the radius of curvature of the lens surface of the image side is R _2A , the radius of curvature of the lens surface on the object side of the lens LB is R _1B , and the lens on the image side. Let the radius of curvature of the surface be R _2B (however, the sign of the radius of curvature in the direction that is convex toward the object side is positive).

At this time, the following conditional expressions (13) and (14) are satisfied at the same time, or among the lenses LA and LB, the lens located on the image side has a convex meniscus lens on the object side, the object side It is preferable that the lens located on the side is a meniscus lens having a convex shape on the image side.
R _1A × R _2A <0 (13)
R _1B × R _2B <0 (14)
Conditional expression (5) relates to the arrangement positions of the lens LA and the lens LB. Exceeding the upper limit value of conditional expression (5) is not preferable because a space for arranging one of the lens LA and the lens LB is lost.

  On the other hand, when the lower limit value of conditional expression (5) is exceeded, the lens LA and the lens LB are disposed away from each other, or both the lens LA and the lens LB are disposed relatively close to the aperture stop. become. In the former case, even if the change in the refractive index due to the temperature of the lens LA and the lens LB can be canceled, the way of the light beam is greatly different, so that the aberration cannot be canceled, and in particular, spherical aberration and curvature of field remain. This is not preferable. In the latter case, the height of the off-axis principal ray that passes through the lens LA and the lens LB becomes low, so that the lateral chromatic aberration cannot be effectively corrected and is left unfavorable.

  Conditional expression (5) is more preferably set as follows.

0.50 <d _SL / L _SP <0.95 (5a)
Conditional expression (5a) is more preferably set as follows.

0.55 <d _SL / L _SP <0.90 (5b)
Conditional expression (5b) is more preferably set as follows.

0.60 <d _SL / L _SP <0.87 (5c)
Conditional expression (6) relates to the difference between the Abbe numbers of the materials of the lens LA and the lens LB (the average value of the Abbe numbers when there are a plurality of lenses LA and LB). If the upper limit of conditional expression (6) is exceeded, the Abbe number difference between the materials of the lens LA and the lens LB becomes large. Then, when the refractive indexes of both lenses change with temperature, the deviation of chromatic aberration also increases. For this reason, it is not preferable because the aberration including the chromatic aberration cannot be canceled and the chromatic aberration remains.

  Conditional expression (6) is more preferably set as follows.

│ν _A0 −ν _B0 │ <12 (6a)
Conditional expression (6a) is more preferably set as follows.

│ν _A0 −ν _B0 │ <9 (6b)
Conditional expression (6b) is more preferably set as follows.

│ν _A0 −ν _B0 │ <7 (6c)
Conditional expressions (7) and (8) relate to the Abbe numbers of the materials of the lenses LA and LB. The range indicated by the conditional expression is shown in FIG. When the upper limit value of conditional expressions (7) and (8) is exceeded, the Abbe numbers of the materials of the lens LA and the lens LB become large. If it does so, since it will become low dispersion | distribution, since the chromatic aberration correction effect will become small in the same power, it is not preferable.

  On the other hand, when the lower limit value of conditional expressions (7) and (8) is exceeded, the Abbe numbers of the materials of the lens LA and the lens LB become too small. This is advantageous in terms of chromatic aberration correction power, but is not preferable because the sensitivity of the chromatic aberration correction power due to power becomes too high, making it difficult to manufacture. Conditional expressions (7) and (8) are more preferably set as follows.

12 <ν _A <35 (7a)
12 <ν _B <35 (8a)
The conditional expressions (7a) and (8a) are more preferably set as follows.

15 <ν _A <32 (7b)
15 <ν _B <32 (8b)
The conditional expressions (7b) and (8b) are more preferably set as follows.

17 <ν _A <28 (7c)
17 <ν _B <28 (8c)
Conditional expressions (9) and (10) relate to the refractive indexes and Abbe numbers of the materials of the lenses LA and LB. The range indicated by the conditional expression is shown in FIG. When the upper limit value or lower limit value of conditional expressions (9) and (10) are exceeded, the dispersion of both the lens LA and the lens LB becomes small with respect to the refractive index, or both the lens LA and the lens LB are refracted with respect to the dispersion. The rate will be small. In that case, particularly in order to effectively correct the lateral chromatic aberration between the g-line and the F-line, a large power must be applied. If so, the contribution of other aberrations also increases, and in particular, it becomes difficult to achieve both correction of lateral chromatic aberration and correction of astigmatism and coma aberration.

Conditional expressions (9) and (10) are more preferably set as follows.
_{^{2.800 × 10 -8 × ν A 4}} -7.710 × 10 -5 × ν A 3 + 6.740 × 10 -4 × ν A 2 -2.392 × 10 -2 × ν A +1.780 <N A <3.451 × 10 - ⁸ × ν _A ⁴ -1.088 × 10 ^-5 × ν _A ³ + 1.247 × 10 ^-3 × ν _A ² -6.350 × 10 ^-2 × ν _A +2.677
... Conditions (9a)
_{^{2.800 × 10 -8 × ν B 4}} -7.710 × 10 -5 × ν B 3 + 6.740 × 10 -4 × ν B 2 -2.392 × 10 -2 × ν B +1.780 <N B <3.451 × 10 - ⁸ × ν _B ⁴ -1.088 × 10 ^-5 × ν _B ³ + 1.247 × 10 ^-3 × ν _B ² -6.350 × 10 ^-2 × ν _B +2.677
... Conditional expression (10a)
The conditional expressions (9a) and (10a) are more preferably set as follows.
_{^{2.800 × 10 -8 × ν A 4}} -7.710 × 10 -5 × ν A 3 + 6.740 × 10 -4 × ν A 2 -2.392 × 10 -2 × ν A +1.800 <N A <3.451 × 10 - ⁸ × ν _A ⁴ -1.088 × 10 ^-5 × ν _A ³ + 1.247 × 10 ^-3 × ν _A ² -6.350 × 10 ^-2 × ν _A +2.657
... Condition (9b)
_{^{2.800 × 10 -8 × ν B 4}} -7.710 × 10 -5 × ν B 3 + 6.740 × 10 -4 × ν B 2 -2.392 × 10 -2 × ν B +1.800 <N B <3.451 × 10 - ⁸ × ν _B ⁴ -1.088 × 10 ^-5 × ν _B ³ + 1.247 × 10 ^-3 × ν _B ² -6.350 × 10 ^-2 × ν _B +2.657
... Conditional expression (10b)
Conditional expression (11) relates to the power of the first lens unit L1 and the total length of the photographing optical system L0. When the upper limit of conditional expression (11) is exceeded, the power of the first lens unit L1 becomes too small or the overall length becomes too long. If the power of the first lens unit L1 becomes too small, it is advantageous for aberration correction, but it is not preferable because the convergence effect becomes weak and the problem of downsizing cannot be solved. The same applies to the case where the total length becomes longer.

  On the other hand, if the lower limit value of conditional expression (11) is exceeded, the power of the first lens unit L1 becomes too large or the overall length becomes too short. In order to solve the problem of downsizing, it is advantageous that the total length is short, but if the power of the first lens unit L1 becomes too large, a large number of lenses are required for correcting spherical aberration and coma aberration. . This is not preferable because the problem of downsizing cannot be solved. It is preferable for aberration correction that the balance between the power and the total length of the first lens unit L1 is in the range of the conditional expression (11).

Conditional expression (11) is more preferably set as follows.

The conditional expression (11a) is more preferably set as follows.

Conditional expression (12) relates to the power, Abbe number, and abnormal partial dispersion ratio of the lens LA. This means that when a plurality of the lenses LA are arranged, the sum of Δθ _gFA × φ _A / ν _A is divided by the power φ of the entire system. Exceeding the upper limit value or lower limit value of conditional expression (12) is not preferable because the correction amount balance of the chromatic aberration of magnification between the g line and the F line cannot be achieved with respect to the correction amount of the chromatic aberration of magnification between the C line and the F line.

Conditional expression (12a) is more preferably set as follows.

  Regarding the shapes of the lens LA and the lens LB, the conditional expressions (13) to (14) are satisfied at the same time, or the lens located on the image side of the lens LA and the lens LB is convex on the object side. The meniscus lens is preferably a meniscus lens having a convex shape on the object side.

  Conditional expressions (13) to (14) represent the directions of the curvature radii of the object-side surface and the image-side surface of the lens LA and lens LB. That the product of the radius of curvature of the object side surface and the image side surface indicates a negative value indicates that the signs of the curvature radii of the object side surface and the image side surface are opposite, One of the lens LA and the lens LB is a biconvex shape and one of them is a biconcave shape.

  Then, it becomes possible to cancel the change in aberration (particularly the change in astigmatism) caused by the change in the radius of curvature of each lens surface when the lens LA and the lens LB expand / contract due to the temperature change. Specifically, aberrations (particularly astigmatism) caused by changes in the object-side surface (expansion / contraction) of a biconvex lens and changes in the object-side surface (expansion / contraction) of a biconcave lens ) Cancel each other, and the image side surface can be canceled in the same way. The same applies to the latter meniscus shape.

  However, if the meniscus lens direction is opposite to the above-described direction, the direction of occurrence of astigmatism caused by the curvature change of each surface of the lens LA and the lens LB (especially the object side surface) is the same. This is not preferable because it cannot be canceled out.

  As described above, according to each embodiment, even when a resin lens is used for correcting chromatic aberration in a telephoto lens, the temperature compensation of the refractive index is easy, and the entire system can be miniaturized. Is obtained.

  Next, the features of the lens configuration of each example will be described.

  The reference numeral attached to each lens corresponds to the reference numeral attached to each lens described above. First, the lens configuration common to each embodiment will be described.

  In the photographic optical system of each embodiment, the first lens unit L1 having a positive power (refractive power), the second lens unit L2 having a negative power, and the third lens unit L3 having a positive or negative power in order from the most object side. It is configured. In addition, an opening SP is provided on the image side of the first lens unit L1. The third lens unit L3 includes a thirty-first lens unit L31 having positive or negative power, a thirty-second lens unit L32 having negative power, and a thirty-third lens unit L33 having positive power.

  Then, the correction (vibration compensation) of the photographed image when the photographing optical system vibrates is used as the movable lens group (image displacement correction group). Then, it is moved so as to have a component in a direction orthogonal to the optical axis as indicated by an arrow LT. In each example other than Example 4, a diffractive optical element DOE is used in the first lens unit L1.

In the lens cross-sectional view, DOE is a diffractive optical element. The D surface is a diffractive optical part (diffractive optical surface) constituting a part of the diffractive optical element DOE. Of the diffracted light generated from the diffractive optical part D, the diffraction order m of the diffracted light used in each embodiment is 1, and the design wavelength λ ₀ is the wavelength of the d-line (587.56 nm). The diffractive optical surface D provided in the photographic optical system L0 is not limited to one, and a plurality of diffractive optical surfaces D may be used. According to this, a further excellent optical performance is obtained. The diffractive optical surface D is not limited to a spherical surface but may be an aspherical surface. The base material may be glass or plastic as long as it transmits light.

As for the shape of the diffraction grating, the phase φ (H) at the distance H from the optical axis is expressed by the following equation when the phase coefficient of the 2i-order term is C _2i . Where m is the diffraction order and λ ₀ is the reference wavelength.

In general, the Abbe number (dispersion value) ν _d of refractive optical materials such as lenses and prisms is d, C, F
When the refractive power at each wavelength of the line is N _d , N _C , N _F , it is expressed by the following formula.

ν _d = (N _d −1) / (N _F −N _C )> 0 (b)
On the other hand, the Abbe number ν _d of the diffractive optical unit is ν _d = λ _d / (λ _F −λ _C ) (c) when the wavelengths of the d, C, and F lines are λ _d , λ _C , and λ _F. )
Ν _d = −3.453.

The partial dispersion ratio θ _gF is θ _gF = (λ _g −λ _F ) / (λ _F −λ _C ) (d)
And θ _gF = 0.2956.

Thereby, the dispersibility at an arbitrary wavelength has an adverse effect on the refractive optical element. Further, the refractive power φ _D of the paraxial temporary diffracted light (m = 1) at the reference wavelength of the diffractive optical part is C _{2 as} the coefficient of the second-order term from the previous equation (a) representing the phase of the diffractive optical part. Where φ _D = −2 · C ₂ . From this, the focal length f _DOE by only the diffraction component of the diffractive optical element _DOE is

It becomes. Further, when the arbitrary wavelength is λ and the reference wavelength is λ ₀ , the refractive power change with respect to the reference wavelength of the arbitrary wavelength is expressed by the following equation.

φ _D '= (λ / λ ₀ ) × (−2 · C ₂ ) (g)
Thus, as a feature of the diffractive optical part, by varying the phase coefficients C ₂ of Equation (a), large dispersion can be obtained by a weak paraxial refractive power change. This means that chromatic aberration is corrected without greatly affecting various aberrations other than chromatic aberration. As for the higher-order coefficients after the phase coefficient C _4, the change in refractive power with respect to the change in the incident light height of the diffractive optical part can provide an effect similar to that of an aspherical surface. At the same time, it is possible to change the refractive power at an arbitrary wavelength with respect to the reference wavelength according to the change in the incident light height. Therefore, it is effective for correcting lateral chromatic aberration.

Next, a detailed configuration in each embodiment will be described.
[Example 1]
The imaging optical system L0 of Example 1 in FIG. 1A will be described.

  The first lens unit L1 includes two meniscus positive lenses that are convex from the object side to the object side, a cemented lens of a negative lens and a positive lens, and a biconvex lens. The cemented lens constitutes a diffractive optical element DOE. The diffractive optical part D constituting the diffractive optical element DOE is arranged on the cemented surface of the cemented lens. The object-side lens surface of the most image-side biconvex lens of the first lens unit L1 is aspheric.

  The second lens unit L2 is composed of one negative lens. The aperture that determines the axial maximum luminous flux diameter is disposed between the second lens unit L2 and the third lens unit L3 as an aperture stop SP having a variable aperture diameter. Further, in the third lens unit L3, the 31st lens unit L31 is composed of two sets of cemented lenses. The cemented lens on the object side is a cemented lens composed of a negative lens and a positive lens.

  The cemented lens on the image side is composed of a cemented lens composed of a positive lens and a negative lens. The most image-side surface of the image-side cemented lens is an aspherical surface. The thirty-second lens unit L32 includes a pair of cemented lenses obtained by cementing a positive lens and a negative lens, and one negative lens. The thirty-third lens unit L33 includes a pair of cemented lenses including a positive lens and a negative lens, two positive lenses, and one negative lens. Further, the image side surface of the most image side negative lens of the 33rd lens unit L33 is aspherical.

  In the 33rd lens unit L33, a meniscus positive lens convex on the image side corresponds to the lens LB, and a meniscus negative lens convex on the object side corresponds to the lens LA. The material constituting the lens LA is the thermosetting resin 1, and the material constituting the lens LB is the thermosetting resin 2. The optical characteristics of both materials are shown in Table-1. Note that focusing from an infinite object to a close object is performed by moving the second lens unit L2 on the optical axis to the image plane side.

[Example 2]
The imaging optical system L0 of Example 2 shown in FIG. 2A will be described.

  The first lens unit L1 includes, in order from the object side, a biconvex lens, a meniscus positive lens having a convex shape on the object side, a pair of cemented lenses including a negative lens and a positive lens, and one biconvex lens. The cemented lens constitutes a diffractive optical element DOE. The diffractive optical part D constituting the diffractive optical element DOE is arranged on the cemented surface of the cemented lens. The image side biconvex object-side lens surface of the first lens unit L1 is aspheric.

  The second lens unit L2 is composed of one negative lens. The aperture that determines the axial maximum luminous flux diameter is disposed between the second lens unit L2 and the third lens unit L3 as an aperture stop SP having a variable aperture diameter. Further, in the third lens unit L3, the thirty-first lens unit L31 includes one set of cemented lens and one negative lens. The cemented lens is a cemented lens including one negative lens and one positive lens, and the most image side surface of the cemented lens is an aspherical surface.

  The thirty-second lens unit L32 includes a pair of cemented lenses obtained by cementing a positive lens and a negative lens, and one negative lens. The thirty-third lens unit L33 includes, in order from the object side, a biconvex lens, a cemented lens including a negative lens and a positive lens, a biconvex lens, and a biconcave lens. The image-side surface of the most image-side biconcave lens in the 33rd lens unit L33 is aspheric. In the thirty-third lens unit L33, the biconvex lens disposed closest to the object side corresponds to the lens LB, and the biconcave lens closest to the image side corresponds to the lens LA.

  The material constituting the lens LA is an acrylic UV curable resin, and the material constituting the lens LB is the thermosetting resin 3. The optical characteristics of both materials are shown in Table-1.

  Note that focusing from an infinite object to a close object is performed by moving the second lens unit L2 on the optical axis to the image plane side.

[Example 3]
The photographic optical system L0 of Example 3 shown in FIG. 3A will be described.

  The first lens unit L1 includes, in order from the object side, a biconvex lens, a meniscus positive lens having a convex shape on the object side, a pair of cemented lenses including a negative lens and a positive lens, and one biconvex lens. The cemented lens constitutes a diffractive optical element DOE. The diffractive optical part D constituting the diffractive optical element DOE is arranged on the cemented surface of the cemented lens. The image side biconvex object-side lens surface of the first lens unit L1 is aspheric.

  The second lens unit L2 is composed of one negative lens. The aperture that determines the axial maximum luminous flux diameter is disposed between the second lens unit L2 and the third lens unit L3 as an aperture stop SP having a variable aperture diameter. Further, in the third lens unit L3, the thirty-first lens unit L31 includes one set of cemented lens and one negative lens. The cemented lens is a cemented lens including one negative lens and one positive lens, and the most image side surface of the cemented lens is an aspherical surface.

  The thirty-second lens unit L32 includes a pair of cemented lenses obtained by cementing a positive lens and a negative lens, and one negative lens. The thirty-third lens unit L33 includes, in order from the object side, a meniscus positive lens having a convex shape on the object side, a biconcave lens, a biconvex lens, a biconvex lens, and a biconcave lens. The image-side surface of the most image-side biconcave lens in the 33rd lens unit L33 is aspheric. In the 33rd lens unit L33, the second positive lens (biconvex lens) and the third positive lens (biconvex lens) correspond to the lens LB, and the two biconcave lenses correspond to the lens LA.

  Of the two biconcave lenses constituting the lens LA, the material constituting the object side lens LA is an acrylic UV curable resin, and the material constituting the image side lens LA is N-polyvinylcarbazole. Of the two positive lenses constituting the lens LB, the material constituting the object side lens LB is the thermosetting resin 2, and the material constituting the image side lens LB is the thermosetting resin 3. The optical properties of these materials are shown in Table-1.

  Note that focusing from an infinite object to a close object is performed by moving the second lens unit L2 on the optical axis to the image plane side.

[Example 4]
The photographic optical system L0 of Example 4 shown in FIG. 4A will be described.

  The first lens unit L1 includes, in order from the object side, two meniscus positive lenses having a convex shape on the object side, a cemented lens of a positive lens and a negative lens, a cemented lens of a negative lens and a positive lens, and a biconvex lens. The object-side lens surface of the most image-side biconvex lens of the first lens unit L1 is aspheric.

  The second lens unit L2 is composed of one negative lens. The aperture that determines the axial maximum luminous flux diameter is disposed between the second lens unit L2 and the third lens unit L3 as an aperture stop SP having a variable aperture diameter. Further, in the third lens unit L3, the 31st lens unit L31 is composed of two sets of cemented lenses. The cemented lens on the object side is a cemented lens composed of a negative lens and a positive lens.

  The cemented lens on the image side is composed of a cemented lens composed of a positive lens and a negative lens. The most image-side surface of the image-side cemented lens is an aspherical surface. The thirty-second lens unit L32 includes a pair of cemented lenses obtained by cementing a positive lens and a negative lens, and one negative lens. The thirty-third lens unit L33 includes, in order from the object side, a pair of cemented lenses composed of a positive lens and a negative lens, a pair of cemented lenses composed of a positive lens and two negative lenses, and a negative lens. Yes. The object-side surface of the most image-side negative lens of the thirty-third lens unit L33 is aspheric.

  In the 33rd lens unit L33, a meniscus positive lens convex on the image side corresponds to the lens LA, and a meniscus negative lens convex on the object side corresponds to the lens LB. The material that constitutes the lens LA is an ITO 14.2% -UV curable resin 2 in which 14.2% of ITO fine particles are dispersed in the UV curable resin 2, and the material that constitutes the lens LB is the thermosetting resin 2. The optical characteristics of both materials are shown in Table-1. Note that focusing from an infinite object to a close object is performed by moving the second lens unit L2 on the optical axis to the image plane side.

  Numerical examples 1 to 4 corresponding to the first to fourth embodiments of the present invention will be shown below.

  In each numerical example, i indicates the order of the surfaces from the object side, ri is the radius of curvature of the i-th surface from the object side, di is the i-th and i + 1-th distance from the object side, and ndi and νdi Are the refractive index and Abbe number of the i-th optical member. f, Fno, and 2ω respectively represent the focal length, F number, and angle of view (degree) of the entire system when focusing on an object at infinity. BF is the back focus in terms of air.

In each numerical example, the two surfaces closest to the image side are glass blocks such as filters. The diffractive optical element (diffractive surface) is expressed by giving a phase coefficient of the phase function of the above-described equation (a). The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, k is the eccentricity, and A4, A6, A8, and A10 are aspherical surfaces. As a coefficient

It is expressed by the following formula.

Further, for example, “e-Z” means “10-Z”. Table 1 and Table 2 show the material characteristics of the lens LA and the lens LB and the numbers of the numerical examples used. The refractive index of the ITO fine particle dispersed material is calculated using the value calculated using the above-described equation (A). Table 3 shows the relationship between the above-described conditional expressions and numerical values in the numerical examples.


(Numerical example 1)
f = 585.05mm Fno = 4.12 2ω = 4.24
Surface number rd nd vd Effective diameter
1 171.314 19.14 1.58144 40.8 142.00
2 83547.455 0.35 140.81
3 108.748 19.56 1.43387 95.1 129.36
4 357.504 51.37 126.32
5 -1971.903 5.00 1.91082 35.3 80.97
6 (Diffraction) 66.752 12.92 1.48749 70.2 73.43
7 309.847 42.26 72.46
8 (Aspherical surface) 74.848 11.33 1.48749 70.2 61.18
9 -209.524 5.75 59.92
10 227.418 2.50 1.85026 32.3 52.13
11 53.599 58.83 48.46
12 (Aperture) ∞ 10.50 39.71 Aperture stop SP
13 38.927 2.00 1.91082 35.3 40.56
14 24.857 13.17 1.59551 39.2 37.87
15 -114.453 1.00 37.20
16 65.566 5.03 1.48749 70.2 34.33
17 -179.046 2.00 1.80610 40.4 33.19
18 (Aspherical surface) 52.175 6.21 31.20
19 -338.487 2.81 1.84666 23.8 30.14
20 -95.341 1.70 1.58913 61.1 29.91
21 61.581 2.59 29.05
22 -752.733 2.50 1.67790 55.3 29.04
23 46.069 3.00 29.08
24 50.915 9.12 1.58144 40.8 30.58
25 -28.664 2.00 1.88300 40.8 30.72
26 132.419 5.03 32.58
27 -140.631 3.66 1.63550 23.9 34.77 LB
28 -59.175 3.09 35.84
29 43.833 7.07 1.76182 26.5 41.16
30 -3739.696 1.00 40.78
31 300.000 2.00 1.64040 18.9 40.13 LA
32 (Aspherical) 60.000 7.00 38.77
33 ∞ 2.00 1.51633 64.1 39.00
34 ∞ 60.51 39.09
Image plane ∞

Aspheric data 6th surface (diffractive surface)
C 2 = -4.29178e-005 C 4 = -5.19729e-009 C 6 = -2.59620e-013 C 8 = 2.18343e-015
C10 = -4.62988e-018 C12 = 1.57518e-021 C14 = 3.52327e-024 C16 = -4.20633e-027
C18 = 1.72880e-030 C20 = -2.30398e-034

8th page
K = 0.00000e + 000 A 4 = -3.47572e-007 A 6 = -6.38001e-011 A 8 = 1.46694e-014
A10 = -5.06280e-018 A12 = 1.84681e-021

18th page
K = 0.00000e + 000 A 4 = -1.28898e-006 A 6 = -1.99855e-009 A 8 = -9.38199e-012
A10 = 1.88578e-014 A12 = -6.66408e-017

32nd page
K = 0.00000e + 000 A 4 = 1.46357e-006 A 6 = 1.31515e-009 A 8 = 2.70819e-012
A10 = -4.81189e-015 A12 = -7.40949e-018 A14 = 2.53284e-020

Various data Zoom ratio 1.00

Focal length 585.05
F number 4.12
Angle of View 2.12
Statue height 21.64
Total lens length 384.01
BF 60.51

Entrance pupil position 1082.16
Exit pupil position -75.45
Front principal point position -850.19
Rear principal point position -524.53

Lens group data Group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 181.16 161.92 142.34 -110.07
2 10 -83.03 2.50 1.78 0.42
3 12 1558.42 94.50 -287.73 -318.34
31 12 114.20 33.70 -4.71 -26.12
32 19 -38.96 9.61 4.87 -1.69
33 24 88.04 41.98 11.11 -21.21

Single lens Data lens Start surface Focal length
1 1 295.22
2 3 351.85
3 5 -70.81 (value of single lens excluding diffractive optical element)
4 6 171.54 (value of single lens excluding diffractive optical element)
5 8 114.62
6 10 -83.03
7 13 -80.99
8 14 35.55
9 16 99.11
10 17 -49.93
11 19 155.94
12 20 -63.25
13 22 -63.96
14 24 32.93
15 25 -26.53
16 27 158.00
17 29 56.92
18 31 -117.50
G 33 0.00

(Numerical example 2)
f = 584.95mm Fno = 4.12 2ω = 4.24
Surface number rd nd vd Effective diameter
1 384.411 15.32 1.48749 70.2 141.98
2 -676.196 0.50 141.36
3 116.318 23.15 1.43387 95.1 134.01
4 696.728 63.79 131.00
5 -1287.064 4.20 1.88300 40.8 82.99
6 (Diffraction) 87.310 13.77 1.48749 70.2 77.82
7 531.409 23.26 76.53
8 (Aspherical surface) 98.480 10.87 1.48749 70.2 69.53
9 -2748.116 5.50 67.75
10 2487.103 3.00 1.51633 64.1 64.08
11 149.108 45.61 61.63
12 (Aperture) ∞ 11.00 44.68 Aperture stop SP
13 34.530 1.80 1.88300 40.8 38.00
14 24.490 11.93 1.58313 59.4 35.16
15 (Aspherical) -8550.685 2.00 32.41
16 65.253 2.00 1.88300 40.8 28.73
17 28.552 6.82 26.10
18 73.041 4.64 1.84666 23.8 23.81
19 -62.489 1.80 1.88300 40.8 23.36
20 38.191 3.71 22.60
21 -394.920 1.80 1.88300 40.8 23.04
22 71.906 3.74 23.49
23 69.715 6.16 1.60737 27.0 25.97 LB
24 -43.455 2.37 26.60
25 -37.304 2.00 1.88300 40.8 26.53
26 53.208 8.32 1.60342 38.0 28.66
27 -70.395 2.07 31.01
28 57.369 8.91 1.62588 35.7 34.50
29 -42.973 -0.08 34.67
30 -48.766 2.00 1.63555 22.7 34.46 LA
31 (Aspherical) 274.518 5.00 34.57
32 ∞ 2.00 1.51633 64.1 35.11
33 ∞ 64.99 35.28
Image plane ∞

Aspheric data 6th surface (diffractive surface)
C 2 = -3.59557e-005 C 4 = -2.02690e-009 C 6 = 3.82008e-012 C 8 = -1.13718e-014
C10 = 1.97436e-017 C12 = -1.67663e-020 C14 = 3.56371e-024 C16 = 4.33333e-027
C18 = -3.11803e-030 C20 = 6.17609e-034

8th page
K = 0.00000e + 000 A 4 = -1.14286e-007 A 6 = -6.50288e-012 A 8 = -1.84715e-015
A10 = 4.32359e-019

15th page
K = 0.00000e + 000 A 4 = 6.45595e-007 A 6 = -2.56563e-010 A 8 = 7.72570e-014
A10 = -3.92620e-015 A12 = 1.31566e-017 A14 = -1.33552e-020

No. 31
K = 0.00000e + 000 A 4 = -1.43077e-007 A 6 = 1.02116e-009 A 8 = 5.68615e-013
A10 = -2.01685e-015 A12 = 5.04111e-018

Various data Zoom ratio 1.00

Focal length 584.95
F number 4.12
Angle of View 2.12
Statue height 21.64
Total lens length 363.96
BF 64.99

Entrance pupil position 690.64
Exit pupil position -73.29
Front principal point position -1198.90
Rear principal point position -519.96

Lens group data Group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 234.00 154.86 43.90 -124.61
2 10 -307.34 3.00 2.11 0.13
3 12 -154.18 90.00 44.75 -38.60
31 12 -5133.62 28.73 1161.03 930.14
32 18 -38.64 11.95 7.85 -0.57
33 23 75.37 38.76 9.99 -18.80

Single lens Data lens Start surface Focal length
1 1 505.14
2 3 317.98
3 5 -92.47 (value of single lens excluding diffractive optical element)
4 6 212.16 (Value of a single lens excluding diffractive optical elements)
5 8 195.27
6 10 -307.34
7 13 -104.14
8 14 41.90
9 16 -59.00
10 18 40.41
11 19 -26.62
12 21 -68.77
13 23 45.00
14 25 -24.58
15 26 51.52
16 28 40.64
17 30 -65.00
G 32 0.00

(Numerical Example 3)
f = 585.00 mm Fno = 4.12 2ω = 4.24
Surface number rd nd vd Effective diameter
1 196.192 18.74 1.48749 70.2 141.99
2 -5616.125 0.50 141.99
3 138.712 19.27 1.43387 95.1 133.69
4 725.750 63.17 130.70
5 -975.376 4.20 1.88300 40.8 83.89
6 (Diffraction) 99.639 12.94 1.48749 70.2 79.20
7 600.000 56.18 77.84
8 (Aspherical) 119.024 9.48 1.48749 70.2 61.66
9 -876.113 6.40 59.90
10 492.894 3.00 1.51633 64.1 55.50
11 93.958 64.12 53.02
12 (Aperture) ∞ 11.00 33.72 Aperture stop SP
13 57.511 1.80 1.88300 40.8 32.90
14 41.712 7.35 1.51823 58.9 32.10
15 (Aspherical) -99.565 4.20 31.53
16 205.949 2.00 1.88300 40.8 28.97
17 65.665 4.00 28.07
18 59.071 4.48 1.84666 23.8 27.36
19 -67.171 1.80 1.88300 40.8 26.95
20 34.774 5.13 25.56
21 -116.153 1.80 1.88300 40.8 26.01
22 69.456 4.54 26.89
23 36.490 5.61 1.54814 45.8 33.22
24 352.512 2.61 33.43
25 -675.486 2.00 1.63555 22.7 33.85 LA
26 39.970 0.50 34.77
27 42.290 5.86 1.63550 23.9 35.16 LB
28 -701.287 0.30 35.47
29 74.156 4.57 1.60737 27.0 36.17 LB
30 -504.079 0.50 36.10
31 -502.649 2.00 1.69591 17.7 36.05 LA
32 (Aspherical surface) 297.543 5.00 35.95
33 ∞ 2.00 1.51633 64.1 36.50
34 ∞ 50.94 36.67
Image plane ∞

Aspheric data 6th surface (diffractive surface)
C 2 = -4.17482e-005 C 4 = -1.98068e-010 C 6 = 4.34965e-012 C 8 = -1.33886e-014
C10 = 2.04518e-017 C12 = -1.63832e-020 C14 = 3.48559e-024 C16 = 4.22683e-027
C18 = -3.13657e-030 C20 = 6.40178e-034

8th page
K = 0.00000e + 000 A 4 = -9.42876e-008 A 6 = -5.84084e-012 A 8 = 1.72968e-015
A10 = -1.41651e-019

15th page
K = 0.00000e + 000 A 4 = 1.93187e-006 A 6 = -2.22284e-010 A 8 = -6.20424e-012
A10 = 3.13004e-014 A12 = -6.89496e-017 A14 = 4.68543e-020

32nd page
K = 0.00000e + 000 A 4 = 1.50765e-006 A 6 = 2.96197e-009 A 8 = -3.17602e-012
A10 = 9.35047e-015 A12 = -2.52254e-018

Various data Zoom ratio 1.00

Focal length 585.00
F number 4.12
Angle of View 2.12
Statue height 21.64
Total lens length 388.00
BF 50.94

Entrance pupil position 1249.39
Exit pupil position -64.36
Front principal point position-1133.67
Rear principal point position -534.06

Zoom lens group data Group Start surface Focal length Lens composition length Front principal point position Rear principal point position
1 1 254.84 184.48 97.00 -150.21
2 10 -225.41 3.00 2.45 0.47
3 12 -244.62 79.06 43.60 -27.35
31 12 274.60 26.35 -11.64 -31.02
32 18 -32.25 13.21 9.14 -0.72
33 23 56.35 30.95 3.29 -19.86

Single lens Data lens Start surface Focal length
1 1 389.28
2 3 391.37
3 5 -102.20 (value of a single lens excluding diffractive optical elements)
4 6 243.03 (value of single lens excluding diffractive optical element)
5 8 215.63
6 10 -225.41
7 13 -181.67
8 14 57.75
9 16 -109.91
10 18 37.74
11 19 -25.74
12 21 -49.00
13 23 73.79
14 25 -59.31
15 27 62.95
16 29 106.75
17 31 -268.30
G 33 0.00

(Numerical example 4)
f = 594.73mm Fno = 4.12 2ω = 4.16
Surface number rd nd vd Effective diameter
1 (Aspherical) 156.532 18.22 1.74950 35.3 144.36
2 949.214 0.35 143.05
3 116.336 19.81 1.43387 95.1 130.77
4 630.750 9.30 128.17
5 54031.818 10.88 1.75520 27.5 120.61
6 -233.045 5.00 1.85026 32.3 118.60
7 564.663 37.13 109.95
8 1013.106 5.00 1.74950 35.3 77.72
9 42.085 17.00 1.49700 81.5 66.78
10 185.922 3.50 65.94
11 (Aspherical) 59.673 14.54 1.43387 95.1 64.18
12 -175.521 4.00 62.94
13 387.668 2.50 1.80000 29.8 55.54
14 58.936 59.90 51.39
15 (Aperture) ∞ 10.50 37.53 Aperture stop SP
16 74.707 2.00 1.85026 32.3 34.32
17 22.816 14.84 1.56732 42.8 32.00
18 -48.590 1.00 31.48
19 -165.972 8.44 1.64769 33.8 29.77
20 -24.715 2.00 1.88300 40.8 28.87
21 (Aspherical) -74.386 2.00 29.61
22 -349.740 2.81 1.84666 23.8 28.87
23 -120.341 1.70 1.48749 70.2 28.70
24 48.465 3.22 27.98
25 199.446 2.50 1.62041 60.3 28.08
26 38.357 3.38 28.01
27 46.021 11.86 1.75520 27.5 29.59
28 -26.110 2.00 1.88300 40.8 29.46
29 -72.500 3.08 29.79
30 -65.000 4.50 1.56480 20.0 29.04 LA
31 -40.000 2.00 29.07
32 -30.694 1.50 1.92286 18.9 28.51
33 -51.111 1.04 1.88300 40.8 29.30
34 -80.805 1.00 29.79
35 (Aspherical) 135.111 2.00 1.63550 23.9 30.45 LB
36 60.000 7.00 30.27
37 ∞ 2.00 1.51633 64.1 31.40
38 ∞ 52.00 31.69
Image plane ∞

Aspheric data 1st surface
K = 0.00000e + 000 A 4 = 9.72896e-009 A 6 = 3.80682e-013 A 8 = 9.77088e-017
A10 = -1.33311e-020 A12 = 1.16552e-024

11th page
K = 0.00000e + 000 A 4 = -2.63642e-007 A 6 = -1.98818e-011 A 8 = 3.33813e-014
A10 = 1.44313e-017 A12 = 1.81065e-020

21st page
K = 0.00000e + 000 A 4 = -3.78115e-006 A 6 = -7.41890e-010 A 8 = -3.70695e-011
A10 = 9.02781e-014 A12 = -9.86045e-017

35th page
K = 0.00000e + 000 A 4 = 9.82184e-006 A 6 = -1.13960e-008 A 8 = 4.39014e-011
A10 = -1.00159e-013 A12 = 8.94552e-017 A14 = -4.80733e-020

Various data Zoom ratio 1.00

Focal length 594.73
F number 4.12
Angle of View 2.08
Statue height 21.64
Total length of lens 351.50
BF 52.00

Entrance pupil position 989.90
Exit pupil position -46.86
Front principal point position-1993.09
Rear principal point position -542.73

Lens group data Group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 164.14 140.72 48.26 -98.72
2 13 -87.17 2.50 1.64 0.25
3 15 -208.73 92.38 105.20 23.09
31 15 109.00 38.78 23.39 -5.23
32 22 -43.15 10.23 5.40 -1.87
33 27 104.63 37.99 -23.06 -43.15

Single lens Data lens Start surface Focal length
1 1 247.65
2 3 324.99
3 5 307.29
4 6 -193.46
5 8 -58.71
6 9 105.32
7 11 104.60
8 13 -87.17
9 16 -39.33
10 17 29.59
11 19 43.81
12 20 -42.72
13 22 215.49
14 23 -70.64
15 25 -77.00
16 27 23.74
17 28 -47.17
18 30 172.90
19 32 -86.31
20 33 -160.15
21 35 -171.61
G 37 0.00

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  Next, each attached drawing will be described. FIGS. 1A to 4A are lens cross-sectional views of Examples 1 to 4 of the photographing optical system of the present invention. FIGS. 1B to 4B are longitudinal aberration diagrams of Examples 1 to 4 of the photographing optical system of the present invention in which the environmental temperature of the optical system is 20 degrees Celsius. FIGS. 1C to 4C are longitudinal aberration diagrams of Examples 1 to 4 of the photographing optical system of the present invention when the environmental temperature of the optical system is −20 degrees Celsius. FIGS. 1D to 4D are longitudinal aberration diagrams of Examples 1 to 4 of the photographing optical system of the present invention in which the environmental temperature of the optical system is 40 degrees Celsius. FIG. 5 is a schematic view of the main part of a single-lens reflex camera system (imaging device) in which the photographing optical system of the present invention is mounted on the camera body.

  In each lens cross-sectional view, L0 is a photographing optical system. SP is an aperture stop. The photographing optical system L0 includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit L3 having a positive or negative value. The third lens unit L3 is moved in order from the object side to the image side so as to have a fixed thirty-first lens unit L31 having a component perpendicular to the optical axis, and shifts the image perpendicular to the optical axis direction. The lens unit L32 includes a fixed 33rd lens unit L33.

  IP is an image plane, and when used as a photographing optical system of a video camera or a digital camera, an imaging surface of a CCD sensor, a CMOS sensor or the like (photoelectric conversion element) that receives an image is used for a silver salt film camera. It corresponds to a film surface when used as an imaging optical system. G is a glass block.

  In each aberration diagram, d and g are d line and g line in this order. M and S are a meridional image plane and a sagittal image plane. Lateral chromatic aberration is represented by the g-line. Fno is the F number, and ω is the half angle of view. In all aberration diagrams, when each numerical example described later is expressed in mm, the spherical aberration is 0.4 mm, the astigmatism is 0.4 mm, the distortion is 2%, and the chromatic aberration of magnification is 0.05 mm. It is.

  Next, an embodiment in which the optical system of the present invention is applied to an imaging apparatus (camera system) will be described with reference to FIG. FIG. 5 is a schematic diagram of a main part of a single-lens reflex camera. In FIG. 5, reference numeral 10 denotes an imaging lens having any one of the photographing optical systems 1 of Examples 1 to 4. The photographing optical system 1 is held by a lens barrel 2 that is a holding member. Reference numeral 20 denotes a camera body. The camera body includes a quick return mirror 3 that reflects the light beam from the imaging lens 10 upward, a focusing plate 4 that is disposed at an image forming position of the imaging lens 10, and a pentagon that converts an inverted image formed on the focusing plate 4 into an erect image. A roof prism 5 is provided. Further, it is constituted by an eyepiece 6 for observing the erect image.

  Reference numeral 7 denotes a photosensitive surface, on which an image pickup device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor, or a silver salt film is arranged. At the time of photographing, the quick return mirror 3 is retracted from the optical path, and an image is formed on the photosensitive surface 7 by the photographing lens 10. As described above, the imaging optical system according to the first to fourth embodiments is applied to an imaging apparatus such as a photographic camera, a video camera, or a digital still camera, thereby realizing a lightweight imaging apparatus having high optical performance.

  Note that the photographing optical system of the present invention can also be applied to an image pickup apparatus without a quick return mirror.

L0 photographing optical system, L1 first lens group, L2 second lens group, L3 third lens group,
L31 31st lens group, L32 32nd lens group, L33 33rd lens group,
DOE diffractive optical element, D diffractive optical part, LA lens LA, LB lens LB
G glass block

Claims (12)

Having an aperture stop,
At 20 degrees Celsius, the image side of the aperture stop has at least one lens LA that satisfies the conditional expression (1),
Similarly, at least one lens LB having a different focal length sign from that of the lens LA is provided on the image side of the aperture stop.
At 20 degrees Celsius, when the anomalous partial dispersion ratio of the lens LA is Δθ _gFA , the power of the lens LA is φ _A , the power of the lens LB is φ _B , and the power of the entire system at infinity is φ,
Δθ _gFA × φ _A <0 (1)
0.0272 <│Δθ _gFA │ <0.3000 (2)
An imaging optical system characterized by satisfying the following conditions:   The imaging optical system has a first lens group that is fixed and has positive refractive power at the most object side during focusing, and is a second lens that is movable and has negative refractive power when focusing on the image side than the first lens group. 2. The lens according to claim 1, further comprising an aperture stop closer to the image side than the first lens group, and a combined refractive power of a lens located on the object side with the aperture stop as a boundary. Shooting optical system.   Light that has a first lens group that is fixed at the most object side and has positive refractive power at the time of focusing, and light on the paraxial axis on the object side passes through the lens surface from the point where the optical axis and the paraxial ray of the pupil intersect. The maximum value of the height from the optical axis where the paraxial beam on the image side passes through the lens surface from the point where the optical axis and the pupil paraxial beam intersect is higher than the maximum value from the axis. The photographing optical system according to claim 1, wherein the photographing optical system is small.   The photographic optical system according to any one of claims 1 to 3, wherein a material constituting both the lens LA and the lens LB is a resin material. From the aperture stop at 20 degrees Celsius, the distance on the optical axis to the object side apex of said lens LA and the lens lens is disposed closer to the aperture stop of the LB and d _SL, from the aperture stop the distance along the optical axis between the surface apex of the image side of the most image are arranged in side lens in the photographing optical system and L _SP. At this time,
0.4 <d _SL / L _SP <0.97 (5)
The imaging optical system according to any one of claims 1 to 4, wherein the following condition is satisfied. At 20 degrees Celsius, the d-line reference Abbe number (average value of Abbe numbers when there are a plurality of lenses LA) of the material constituting the lens LA is ν _A0 , and the d-line reference Abbe number of the material constituting the lens LB is used. The number (the average value of the Abbe number when there are a plurality of lenses LB) is represented by ν _B0 . At this time,
│ν _A0 −ν _B0 │ <15 (6)
The imaging optical system according to claim 1, wherein the following condition is satisfied. At 20 degrees Celsius, the Abbe number based on the d-line of the material composing the lens LA is ν _A , and the Abbe number based on the d-line of the material composing the lens LB is ν _B. At this time,
10 <ν _A <40 (7)
10 <ν _B <40 (8)
The imaging optical system according to claim 1, wherein the following condition is satisfied. At 20 ° C, the lens of the material constituting the LA d-line refractive index N _A of _the refractive index of the d line of the material of the lens LB and N _B. At this time,
^{_{2.800 × 10 -8 × ν A 4}} -7.710 × 10 -5 × ν A 3 + 6.740 × 10 -4 × ν A 2 -2.392 × 10 -2 × ν A +1.750 <N A <3.451 × 10 - ⁸ × ν _A ⁴ -1.088 × 10 ^-5 × ν _A ³ + 1.247 × 10 ^-3 × ν _A ² -6.350 × 10 ^-2 × ν _A +2.707
... (9)
^{_{2.800 × 10 -8 × ν B 4}} -7.710 × 10 -5 × ν B 3 + 6.740 × 10 -4 × ν B 2 -2.392 × 10 -2 × ν B +1.750 <N B <3.451 × 10 - ⁸ × ν _B ⁴ -1.088 × 10 ^-5 × ν _B ³ + 1.247 × 10 ^-3 × ν _B ² -6.350 × 10 ^-2 × ν _B +2.707
... (10)
The photographic optical system according to claim 1, wherein the following condition is satisfied. At 20 degrees Celsius, the power of the first lens group of the photographing optical system is φ ₁ , and the optical axis from the vertex of the object side lens surface of the lens closest to the object side to the imaging surface when focused to infinity in the photographing optical system When the upper distance is L and the power of the entire system at the time of focusing at infinity in the photographing optical system is φ,
The imaging optical system according to claim 1, wherein the following condition is satisfied. At 20 degrees Celsius, the anomalous partial dispersion ratio of the lens LA is Δθ _gFA , the power of the lens LA is φ _A , the d-line reference Abbe number of the material constituting the lens LA is ν _A , and the entire system at the time of focusing at infinity When the power of
The imaging optical system according to claim 1, wherein the following condition is satisfied. The radius of curvature of the lens surface on the object side of the lens LA is R _1A , the radius of curvature of the lens surface of the image side is R _2A , the radius of curvature of the lens surface on the object side of the lens LB is R _1B , and the lens on the image side. The radius of curvature of the surface is R _2B (however, the sign of the radius of curvature in the direction of convexity on the object side is positive)
R _1A × R _2A <0 (13)
R _1B × R _2B <0 (14)
Of the lens LA and the lens LB, the lens located on the image side is convex on the object side, and the lens located on the object side is convex on the image side. The imaging optical system according to claim 1, wherein the imaging optical system is a lens.   12. An imaging apparatus comprising: the imaging optical system according to claim 1; and an imaging element that receives an image formed by the imaging optical system.