WO2014203675A1 - Compound-eye imaging optical system and compound-eye imaging device - Google Patents

Compound-eye imaging optical system and compound-eye imaging device Download PDF

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Publication number
WO2014203675A1
WO2014203675A1 PCT/JP2014/063541 JP2014063541W WO2014203675A1 WO 2014203675 A1 WO2014203675 A1 WO 2014203675A1 JP 2014063541 W JP2014063541 W JP 2014063541W WO 2014203675 A1 WO2014203675 A1 WO 2014203675A1
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lens
imaging optical
eye imaging
optical system
compound
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PCT/JP2014/063541
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French (fr)
Japanese (ja)
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潤 太田
一生 松井
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コニカミノルタ株式会社
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Priority to JP2015522686A priority Critical patent/JPWO2014203675A1/en
Publication of WO2014203675A1 publication Critical patent/WO2014203675A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/0062—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B15/00—Special procedures for taking photographs; Apparatus therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/40—Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
    • H04N25/41—Extracting pixel data from a plurality of image sensors simultaneously picking up an image, e.g. for increasing the field of view by combining the outputs of a plurality of sensors

Definitions

  • the present invention relates to a compound eye imaging apparatus that forms an object image using a lens array composed of a plurality of lenses and a compound eye imaging optical system used therefor.
  • imaging devices have been mounted on thin smartphones, etc., but there has been a great demand for thin imaging optical systems, and so far it has been manufactured to reduce overall length and increase error sensitivity associated with optical design. This has been addressed by improving accuracy.
  • further thinning ultra-thinning
  • the imaging area is divided and one set of optical systems (single-eye imaging optical system) is arranged in each imaging area, so that the optical total length is significantly larger than before.
  • a compound-eye imaging device In such a compound-eye imaging device, the same subject is photographed by a plurality of single-eye imaging optical systems, and a plurality of low-resolution images output from the imaging device are synthesized by image processing, thereby outputting one high-resolution image.
  • a so-called super-resolution technique can be used, whereby a high-resolution image can be obtained while realizing a significantly lower profile than that of an existing optical system.
  • Such a compound-eye imaging optical system has a small imaging area in which one single-lens imaging optical system forms an object image and has a low number of pixels, but each single-lens imaging optical system has a smaller number of pixels than conventional imaging optical systems.
  • High optical performance is required.
  • Patent Document 1 discloses a compound-eye imaging optical system having a plurality of individual lenses that differ for each wavelength component of a subject.
  • the compound-eye imaging optical system described in Patent Document 1 is composed of one lens array, even if a single lens is designed for each wavelength component, aberration correction is performed with a single lens. Is insufficient, and it is difficult to achieve the required optical performance.
  • the single-eye imaging optical system is formed from a plurality of lenses stacked in the optical axis direction
  • the degree of freedom of aberration correction increases and it becomes easy to form a high-quality image.
  • forming the compound-eye imaging optical system by arranging them in the direction perpendicular to the optical axis increases the labor of assembly. Therefore, by laminating a lens array in which a plurality of lenses (single-lens lenses) are integrally formed in the optical axis direction, a plurality of single-eye imaging optical systems composed of the laminated single-lens lenses are formed at a time. There is an attempt to do.
  • a lens array in which a plurality of single-lens lenses are formed integrally has the advantage that the performance variation of each lens in the lens array can be reduced, and the number of incorporation and formation can be reduced to reduce the cost.
  • the compound-eye imaging optical system is composed of two or more lens arrays.
  • tilting and warping of the lens array is one problem. This problem will be described.
  • subject light beams LB1, LB2, and LB3 are incident on the single-eye imaging optical systems IL1, IL2, and IL3 of the compound-eye imaging optical system having the first lens array LA1 and the second lens array LA2, respectively.
  • the imaging plane I becomes the focus position as indicated by the dotted line for the subject lights LB1, LB2, and LB3.
  • Each of the subject images is appropriately formed.
  • the first lens array LA1 is used as a reference and the second lens array LA2 is displaced from the reference position. That is, when the second lens array LA2 is translated from the dotted line to the position indicated by the solid line, the focus position is shifted as indicated by the solid line, but if the relative position between the compound-eye imaging optical system and the imaging surface I is displaced and adjusted, Since all the focus positions are on the imaging surface I, there are few problems.
  • Patent Document 2 discloses a compound-eye imaging optical system unit in which a plurality of lens arrays are stacked.
  • a compound-eye imaging optical system unit in which a plurality of lens arrays are stacked.
  • the present invention has been made in view of such problems, and in a compound eye imaging optical system having an ultra-low profile and high image quality, the lens interval is different for each single-eye imaging optical system due to the tilt and warp of the lens array. Even if there is a change, it is possible to suppress deterioration in the image quality of the reconstructed image due to variations in the amount of change in image plane position between single-eye imaging optical systems, and a compound eye image pickup optical system that has a small amount of change in image plane position relative to lens spacing changes. And it aims at providing the compound eye imaging device using the same.
  • a compound eye imaging optical system reflecting one aspect of the present invention is a compound eye imaging optical system that forms a plurality of object images on an imaging surface of an imaging element.
  • the compound-eye imaging optical system includes, in order from the object side, a first lens array and a second lens array group having at least one lens array, and each lens array is formed by integrally forming a plurality of individual lenses.
  • a plurality of single-lens imaging optical systems are formed by laminating the single-lens lenses of the first lens array and the second lens array group in the optical axis direction, and a plurality of object images are formed by the plurality of single-eye imaging optical systems.
  • f Total focal length (mm) of the single-eye imaging optical system
  • f2 Focal length of the second lens group (if the second lens array group consists of a single lens array, this is the focal length of the single lens of the lens array, and the second lens array group In the case of two or more lens arrays, it means the combined focal length of two or more single-lens lenses stacked in the optical axis direction in each lens array) (mm) The focal length is calculated at the design center wavelength of each single-eye imaging optical system.
  • the present inventor has studied an optical system in which the amount of change in focus position (the amount of change in image plane position) with respect to the change in lens interval is small.
  • the distance between the axes of the first single-lens lens L1 having a focal length of f1 and the second single-eye lens L2 having a focal length of f2 is defined as d.
  • the focus position is considered as a distance fB from the final lens surface to the focal position, counting in order from the object side.
  • the distance between the axes of the first eye lens L1 and the second eye lens L2 is changed by t as shown in FIG. Even if the change in the distance between the axes occurs, the change amount d (fB) / dt of fB with respect to t may be small in order to suppress the change amount of the focus position.
  • d (fB) / dt changes in a parabolic shape with respect to f2 and has an extreme value, so that the value of d (fB) / dt can be kept small within a certain f2 range. That is, it can be seen that the amount of change in fB can be suppressed even if t changes.
  • FIG. 3 is a graph plotting the value of equation (10) with f / f2 on the horizontal axis and d (fB) / dt on the vertical axis. It is ideal to set d (fB) / dt to 0, but it is not always necessary to set it to 0, and an image that is practically inconspicuous can be obtained by suppressing it to ⁇ 2.0 or more. At this time, the range of f / f2 is ⁇ 0.6 to 2.
  • this compound-eye imaging optical system by changing the focal length of the second single-lens lens group so as to satisfy the conditional expression (1), the imaging plane position variation with respect to the lens interval change of each single-eye imaging optical system is reduced. It is possible to reduce the size, and the performance variation between the single-eye imaging optical systems can be reduced. More specifically, when the value of the conditional expression (1) is less than the upper limit value and the second lens unit has a positive refractive power (f / f2> 0), imaging with respect to a change in the lens interval is performed. Surface position variation can be suppressed, and a reconstructed image with good image quality can be obtained.
  • conditional expression (1) exceeds the lower limit, when the second lens unit has a negative refractive power (f / f2 ⁇ 0), the image plane position variation with respect to the change in the lens interval is reduced. Therefore, a reconstructed image with good image quality can be obtained.
  • This compound-eye imaging device has the above-described compound-eye imaging optical system.
  • the image quality of the reconstructed image is deteriorated due to variation in the image plane position change amount between the single-lens imaging optical systems. It is possible to provide a compound-eye imaging optical system in which the amount of change in the image plane position relative to the lens interval change is small, and a compound-eye imaging device using the same.
  • (A)-(d) is a figure for demonstrating the example of deformation
  • (A) (b) is a figure which shows the relationship of the focal distance of a single lens. It is a graph which shows the value of Formula (10) by taking f / f2 on a horizontal axis and taking d (fB) / dt on a vertical axis
  • FIG. 3 is a cross-sectional view of a pair of single-lens lenses (single-eye imaging optical system) stacked in the optical axis direction in the compound-eye imaging system of Example 1;
  • FIG. 4 is an aberration diagram of Example 1 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 2.
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 2.
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 2.
  • FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 3.
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 3.
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 3.
  • FIG. 10 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 3 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 10 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 10 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 4;
  • FIG. 6 is an aberration diagram of Example 4 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 10 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 5.
  • FIG. 6 is an aberration diagram of Example 5 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 12 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 6.
  • FIG. 6 is an aberration diagram of Example 6 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 6 is an aberration diagram of Example 6 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • FIG. 10 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 7.
  • FIG. 10 is an aberration diagram of Example 7 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • the compound-eye imaging optical system is an optical system in which a plurality of lens systems are arranged in an array with respect to one imaging device, and each lens system is different from a super-resolution type in which each lens system images the same subject. It is usually divided into a visual field division type for imaging a visual field.
  • a multi-eye imaging optical system according to a super-resolution type that combines a plurality of low-resolution images of the same subject by image processing and outputs one high-resolution image will be described.
  • FIG. 4 schematically shows the imaging apparatus according to the present embodiment.
  • the imaging device DU includes an imaging unit LU, an image processing unit 1, a calculation unit 2, a memory 3, and the like.
  • the imaging unit LU includes one imaging element SR and a compound-eye imaging optical system LH that forms a plurality of images of the same subject on the imaging element SR.
  • the image sensor SR for example, a solid-state image sensor such as a CCD (Charged Coupled Device) type image sensor or a CMOS (Complementary Metal Oxide Semiconductor) type image sensor having a plurality of pixels is used.
  • CCD Charged Device
  • CMOS Complementary Metal Oxide Semiconductor
  • the compound-eye imaging optical system LH is provided on the light-receiving surface SS that is the photoelectric conversion unit of the imaging element SR so that an optical image of the subject is formed, the optical image formed by the compound-eye imaging optical system LH is Then, it is converted into an electrical signal by the image sensor SR.
  • FIG. 5 is an enlarged cross-sectional view of the compound eye imaging optical system LH of FIG.
  • the compound-eye imaging optical system LH includes a first lens array LA1 and a second lens array LA2 in order from the object side. Each lens array is a so-called wafer lens.
  • the first lens array LA1 is formed by forming a plurality of first object side lens portions L1a on the object side of one first parallel plate PP1 and forming a plurality of first image side lens portions L1b on the image side by molding. Yes.
  • the first object-side lens portion L1a, the first parallel plate PP1, and the first image-side lens portion L1b constitute a first single-lens lens IL1.
  • a plurality of second object side lens portions L2a are formed on the object side of one second parallel flat plate PP2, and a plurality of second image side lens portions L2b are formed on the image side by molding. is doing.
  • the second object-side lens portion L2a, the second parallel plate PP2, and the second image-side lens portion L2b constitute a second single-eye lens group IL2.
  • the first eye lens IL1 and the second eye lens group IL2 stacked in the optical axis direction constitute a single eye imaging optical system.
  • the number of single lenses is made equal to the number of object images (referred to as single images) formed on the imaging surface SS of the image sensor SR. That is, the light rays that have passed through the single-lens lenses stacked in the optical axis direction form one image on the imaging surface SS.
  • S is an aperture stop formed around the first object side lens portion L1a
  • F is a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state image sensor, and the like.
  • At least one of the first lens array LA1 and the second lens array LA2 may be integrally molded. Further, the single lens in one lens array may be designed for at least three different wavelength distributions and have different optical characteristics. Further, the single lens in one lens array may be combined with a plurality of color filters having transmittances corresponding to a plurality of different wavelength distributions.
  • the single-eye composite image ML is compressed by the calculation unit 2 and stored in the memory 3.
  • the first monocular lens that is the monocular lens of the first lens array has a positive refractive power.
  • the first single-lens lens have positive refractive power, the total length of the single-eye imaging optical system can be shortened.
  • the first single-eye lens satisfies the following conditional expression. 0.7 ⁇ f1 / f ⁇ 1.5 (2)
  • f1 Focal length of the first single-lens lens (mm)
  • the focal length of the first single-lens lens can be made closer to the focal length of the entire single-lens imaging optical system, and the focal length of the second single-lens lens group can be increased. It is possible to further increase the performance variation suppressing effect between the single-eye imaging optical systems with respect to the change in the interval. Moreover, shortening the overall length can be expected by reducing the focal length of the first single-lens lens. Specifically, when the value of conditional expression (2) is less than the upper limit value, the focal length of the first single-lens lens is reduced, the principal point is advanced, and the optical total length can be shortened. In addition, the angle of view can be widened by reducing the focal length of the first lens. On the other hand, when the value of conditional expression (2) exceeds the lower limit value, the focal length of the second eye lens increases, and fluctuations in the image plane position due to changes in the lens interval can be suppressed. A configuration image can be obtained.
  • the object side surface of the first single-lens lens which is the single-lens of the first lens array has a convex surface on the object side. Since the object side surface of the first monocular lens has a convex surface on the object side, the total length of the monocular imaging optical system can be shortened.
  • the first single-eye lens satisfies the following conditional expression. -5.0 ⁇ g1 ⁇ -0.5 (3)
  • R1 Curvature radius of object side surface of the first single-lens lens (mm)
  • R2 radius of curvature of the image side surface of the first single-lens lens (mm)
  • conditional expression (3) the optical performance of the compound-eye imaging optical system can be improved, and the moldability of the first lens array can be improved.
  • conditional expression (3) is less than the upper limit value, spherical aberration of the first single-eye lens can be suppressed, and a reconstructed image with good image quality can be obtained. Further, the principal point can be advanced to shorten the optical total length of the single-eye imaging optical system.
  • conditional expression (3) exceeds the lower limit value, the curvature of the first single-lens lens does not become too large, and the incidence of coma and the like can be reduced by reducing the light incident angle on the lens surface. Can be suppressed.
  • liquidity of resin can be ensured and a molding precision can be improved by not making curvature too large.
  • the peripheral portion of the surface closest to the image side in the second single-eye lens group has a convex shape on the image side. Since the periphery of the final surface of the second binocular lens group has a convex surface shape on the image side, the light emission angle at a high image height is reduced, and the telecentricity with respect to the imaging surface is improved. There is an effect of suppressing ray intrusion (crosstalk) into the eye imaging area.
  • d2 the distance (mm) between the image side surface of the first single-lens lens, which is the single-lens lens of the first lens array, and the most object-side surface of the second single-lens group
  • conditional expression (4) when the value of conditional expression (4) is below the upper limit value, the principal point can be advanced and the optical total length of the single-eye imaging optical system can be shortened. On the other hand, when the value of conditional expression (4) exceeds the lower limit value, the degree of freedom of the optical surface shape can be improved and the aberration correction capability can be increased by securing a certain distance between the single lenses. Desirably, the following conditional expression is satisfied. 0.1 ⁇ d2 / f ⁇ 0.19 (4 ′)
  • the focal length f2 of the second single-lens lens group in each single-eye imaging optical system satisfies the conditional expression (1).
  • the difference in the focal length f2 of the second single-lens lens group in each single-eye imaging optical system designed in common for all wavelength ranges is zero in design.
  • conditional expression (5) the difference in the focal length f2 of the second single-lens lens group between the single-eye imaging optical systems becomes small regardless of the specifications, and the lens interval With respect to the change, it is possible to suppress variation in the image plane position variation for each single-lens imaging optical system, and a reconstructed image with good image quality can be obtained.
  • conditional expression is satisfied. 0 ⁇ ⁇ (f / f2) max ⁇ 0.05
  • the focal lengths at the respective reference wavelengths of the single-eye imaging optical systems designed for three different wavelength distributions ⁇ ( ⁇ ), ⁇ ( ⁇ ), and ⁇ ( ⁇ ) are f ⁇ , f ⁇ , and f ⁇ . If the focal lengths of the second lens unit are f2 ⁇ , f2 ⁇ , and f2 ⁇ , then
  • S is a surface number
  • the surface on which the aspheric coefficient is described is a surface having an aspheric shape
  • the aspheric shape has the vertex of the surface as the origin and the Z axis in the optical axis direction.
  • the height in the direction perpendicular to the optical axis is represented by the following “Equation 1”.
  • z sag amount of a plane parallel to the optical axis h: height in a direction perpendicular to the optical axis
  • R radius of curvature
  • k conic coefficient (conical constant)
  • a i i-th order aspheric coefficient
  • Example 1 shows lens data of Example 1.
  • the design center wavelength of Example 1 is 546.1 nm.
  • a power of 10 for example, 2.5 ⁇ 10 ⁇ 02
  • E for example, 2.5E-02
  • FIG. 6 is a cross-sectional view of the single-eye imaging optical system of Example 1.
  • IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power
  • IL2 is a second monocular lens group.
  • the peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side.
  • FIG. 7 is an aberration diagram of Example 1 (spherical aberration (a), astigmatism / field curvature (b), distortion aberration (c)).
  • the solid line represents the ray of wavelength 656 nm
  • the dotted line represents the ray of wavelength 546 nm
  • the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
  • the solid line represents the sagittal direction
  • the dotted line represents the meridional direction (the same applies hereinafter).
  • Example 2 Lens data of Example 2 are shown in Tables 2A to 2C.
  • 8 to 10 are sectional views of the single-eye imaging optical system according to the second embodiment.
  • the first lens array and the second lens array are integrally formed (the same applies to the third, fourth, fifth, and seventh embodiments), and the single-eye imaging optical system is designed for each wavelength.
  • the single-eye imaging optical system shown in Table 2A and FIG. 8 is an example in which the optimum design is performed for the red region, and the design center wavelength is 622.0 nm.
  • the single-eye imaging optical system shown in Table 2B and FIG. 9 is an example in which the optimum design is performed for the green region, and the design center wavelength is 544.0 nm.
  • the single-eye imaging optical system shown in Table 2C and FIG. 10 is an example in which the optimum design is performed for the blue region, and the design center wavelength is 458.0 nm.
  • These single-eye imaging optical systems can be formed as a set of three and used together with a corresponding color filter to form one object image.
  • IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power
  • IL2 is a second monocular lens group.
  • the peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side.
  • FIGS. 11 to 13 are aberration diagrams (spherical aberration (a), astigmatism / field curvature (b), distortion aberration (c)) respectively corresponding to the single-eye imaging optical systems of FIGS.
  • Example 3 Lens data of Example 3 are shown in Tables 3A to 3C.
  • 14 to 16 are sectional views of the single-eye imaging optical system according to the third embodiment.
  • the first lens array and the second lens array are integrally formed, and the single-eye imaging optical system is designed for each wavelength.
  • the single-eye imaging optics shown in Table 3A and FIG. The system is an example in which the optimum design is performed for the red region, and the design center wavelength is 622.0 nm.
  • the single-eye imaging optical system shown in Table 3B and FIG. 15 is an example in which the optimum design is performed for the green region, and the design center wavelength is 544.0 nm. Further, the single-eye imaging optical system shown in Table 3C and FIG.
  • FIGS. 17 to 19 are aberration diagrams (spherical aberration (a), astigmatism / field curvature (b), distortion aberration (c)) corresponding to the single-eye imaging optical systems of FIGS. 14 to 16, respectively.
  • Example 4 shows lens data of Example 4.
  • the design center wavelength of Example 4 is 530.0 nm.
  • FIG. 20 is a cross-sectional view of the single-eye imaging optical system of Example 4.
  • IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power
  • IL2 is a second monocular lens
  • IL3 is a third monocular lens.
  • IL2 and IL3 constitute a second monocular lens group.
  • the peripheral portion of the surface closest to the image side of the third eye lens IL3 has a convex shape on the image side.
  • FIG. 21 is an aberration diagram of Example 4 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • the solid line represents the light beam having a wavelength of 570 nm
  • the dotted line represents the light beam having a wavelength of 530 nm
  • the alternate long and short dash line represents the amount of spherical aberration with respect to the light beam having a wavelength of 490 nm.
  • FIG. 22 is a cross-sectional view of the single-eye imaging optical system of Example 5.
  • IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power
  • IL2 is a second monocular lens group.
  • the peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side.
  • I denotes an imaging surface
  • F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like.
  • Example 23 is an aberration diagram of Example 5 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • the solid line represents the ray of wavelength 656 nm
  • the dotted line represents the ray of wavelength 546 nm
  • the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
  • FIG. 24 is a cross-sectional view of the single-eye imaging optical system of Example 6.
  • IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power
  • IL2 is a second monocular lens group.
  • the peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side.
  • I denotes an imaging surface
  • F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like.
  • Example 6 is an aberration diagram of Example 6 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • the solid line represents the ray of wavelength 656 nm
  • the dotted line represents the ray of wavelength 546 nm
  • the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
  • Example 7 shows lens data of Example 7.
  • the design center wavelength of Example 7 is 546.1 nm.
  • FIG. 26 is a cross-sectional view of the single-eye imaging optical system of Example 7.
  • IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power
  • IL2 is a second monocular lens group.
  • I denotes an imaging surface
  • F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like.
  • FIG. 27 is an aberration diagram of Example 7 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
  • the solid line represents the ray of wavelength 656 nm
  • the dotted line represents the ray of wavelength 546 nm
  • the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
  • Table 8 shows the values of each example corresponding to each conditional expression.

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Abstract

This invention provides a compound-eye imaging optical system, and a compound-eye imaging device using same, in which the amount of change in the positions of imaging planes as a function of changes in lens spacing is low. That is, even if inclination or warpage of a lens array causes lens spacing to change for each unit imaging optical system, degradation in the quality of the reconstructed image due to variation in the amount of change in the positions of the imaging planes of the respective unit imaging optical systems is minimized. This compound-eye imaging optical system, which forms a plurality of object images, satisfies condition (1), in which f represents the overall focal length of the unit imaging optical systems in millimeters and f2 represents the focal length of a second unit-lens group in millimeters. (1) −0.6 < f/f2 < 1.5

Description

複眼撮像光学系及び複眼撮像装置Compound eye imaging optical system and compound eye imaging device
　本発明は、複数のレンズから成るレンズアレイを用いて物体像を形成させる複眼撮像装置及びそれに用いる複眼撮像光学系に関する。 The present invention relates to a compound eye imaging apparatus that forms an object image using a lens array composed of a plurality of lenses and a compound eye imaging optical system used therefor.
　近年、撮像装置を薄いスマートフォンなどに搭載することが行われているが、撮像光学系に対する薄型化の要求が非常に大きく、これまでは光学設計による全長短縮やそれに伴う誤差感度増大に対応した製造精度向上により対応してきた。しかし、さらなる薄型化（超薄型化）の要求に対応するためには、従来のように１組の光学系と撮像素子で像を得る構成では限界が見えている。そこで、超薄型化への要求に対応するために、撮像領域を分割しそれぞれの撮像領域に１組の光学系（個眼撮像光学系）を配置することで、従来よりも大幅に光学全長の短縮化が可能となる複眼撮像装置が開発された。 In recent years, imaging devices have been mounted on thin smartphones, etc., but there has been a great demand for thin imaging optical systems, and so far it has been manufactured to reduce overall length and increase error sensitivity associated with optical design. This has been addressed by improving accuracy. However, in order to meet the demand for further thinning (ultra-thinning), there is a limit to the conventional configuration in which an image is obtained with a set of optical systems and an image sensor. Therefore, in order to meet the demand for ultra-thinness, the imaging area is divided and one set of optical systems (single-eye imaging optical system) is arranged in each imaging area, so that the optical total length is significantly larger than before. Has been developed.
　かかる複眼撮像装置において、複数の個眼撮像光学系により同一被写体を撮影し、撮像素子から出力される複数の低解像度画像を画像処理で合成することで、１枚の高解像度画像を出力する、いわゆる超解像技術を用いることができ、これにより既存の光学系よりも大幅な低背化を実現しながらも高解像な画像を得ることができる。 In such a compound-eye imaging device, the same subject is photographed by a plurality of single-eye imaging optical systems, and a plurality of low-resolution images output from the imaging device are synthesized by image processing, thereby outputting one high-resolution image. A so-called super-resolution technique can be used, whereby a high-resolution image can be obtained while realizing a significantly lower profile than that of an existing optical system.
　このような複眼撮像光学系は、１つの個眼撮像光学系が物体像を形成する撮像領域が小さく、低画素数であるとはいえ、各個眼撮像光学系には従来の撮像光学系よりも高い光学性能が要求される。例えば特許文献１には、被写体の波長成分ごとに異なる複数の個眼レンズを有する複眼撮像光学系が開示されている。しかしながら、上記特許文献１に記載の複眼撮像光学系は、１枚のレンズアレイから構成されているので、たとえ波長成分ごとに異なる個眼レンズを設計したとしても、１枚構成のレンズでは収差補正が不十分であり、要求される光学性能の達成は困難である。 Such a compound-eye imaging optical system has a small imaging area in which one single-lens imaging optical system forms an object image and has a low number of pixels, but each single-lens imaging optical system has a smaller number of pixels than conventional imaging optical systems. High optical performance is required. For example, Patent Document 1 discloses a compound-eye imaging optical system having a plurality of individual lenses that differ for each wavelength component of a subject. However, since the compound-eye imaging optical system described in Patent Document 1 is composed of one lens array, even if a single lens is designed for each wavelength component, aberration correction is performed with a single lens. Is insufficient, and it is difficult to achieve the required optical performance.
特開２００１－７８２１２号公報JP 2001-78212 A 特開２０１１－６５０４０号公報JP 2011-65040 A
　これに対し個眼撮像光学系を、光軸方向に積層した複数枚のレンズから形成すると、収差補正の自由度が高まり、高画質な画像を形成しやすくなるが、別個に個眼撮像光学系を形成した上で光軸直交方向に並べて複眼撮像光学系を形成することは、組み立ての手間が増える。そこで、複数のレンズ（個眼レンズ）を一体的に形成したレンズアレイを、光軸方向に積層することで、積層された個眼レンズからなる個眼撮像光学系を複数個一度に形成しようとする試みがある。複数の個眼レンズを一体に形成したレンズアレイは、レンズアレイ内の各レンズの性能ばらつきを小さくできる他、組み込み回数や形成回数を低減しコストを低くできるメリットがある。 On the other hand, when the single-eye imaging optical system is formed from a plurality of lenses stacked in the optical axis direction, the degree of freedom of aberration correction increases and it becomes easy to form a high-quality image. And forming the compound-eye imaging optical system by arranging them in the direction perpendicular to the optical axis increases the labor of assembly. Therefore, by laminating a lens array in which a plurality of lenses (single-lens lenses) are integrally formed in the optical axis direction, a plurality of single-eye imaging optical systems composed of the laminated single-lens lenses are formed at a time. There is an attempt to do. A lens array in which a plurality of single-lens lenses are formed integrally has the advantage that the performance variation of each lens in the lens array can be reduced, and the number of incorporation and formation can be reduced to reduce the cost.
　ゆえに、複眼撮像光学系としては、２枚以上のレンズアレイから構成されることが望ましいが、レンズアレイの傾きや反りが１つの課題となる。かかる課題について説明する。例えば、図１（ａ）において、第１レンズアレイＬＡ１と第２レンズアレイＬＡ２とを有する複眼撮像光学系の各個眼撮像光学系ＩＬ１，ＩＬ２，ＩＬ３に、それぞれ被写体光ＬＢ１，ＬＢ２，ＬＢ３を入射させたものとする。ここで、実線で示す第１レンズアレイＬＡ１に対し、点線で示す第２レンズアレイＬＡ２が基準位置であるとすると、被写体光ＬＢ１，ＬＢ２，ＬＢ３について点線で示すように撮像面Ｉがピント位置となり、被写体像がそれぞれ適切に形成される。ここで、第１レンズアレイＬＡ１を基準とし、第２レンズアレイＬＡ２が基準位置からずれるような課題を想定する。すなわち、第２レンズアレイＬＡ２が点線から実線で示す位置へと平行移動した場合、実線で示すようにピント位置はずれるが、複眼撮像光学系と撮像面Ｉとの相対位置を変位させて調整すれば、撮像面Ｉ上に全てピント位置が乗るので問題は少ない。 Therefore, it is desirable that the compound-eye imaging optical system is composed of two or more lens arrays. However, tilting and warping of the lens array is one problem. This problem will be described. For example, in FIG. 1A, subject light beams LB1, LB2, and LB3 are incident on the single-eye imaging optical systems IL1, IL2, and IL3 of the compound-eye imaging optical system having the first lens array LA1 and the second lens array LA2, respectively. Suppose that Assuming that the second lens array LA2 indicated by the dotted line is the reference position with respect to the first lens array LA1 indicated by the solid line, the imaging plane I becomes the focus position as indicated by the dotted line for the subject lights LB1, LB2, and LB3. Each of the subject images is appropriately formed. Here, a problem is assumed in which the first lens array LA1 is used as a reference and the second lens array LA2 is displaced from the reference position. That is, when the second lens array LA2 is translated from the dotted line to the position indicated by the solid line, the focus position is shifted as indicated by the solid line, but if the relative position between the compound-eye imaging optical system and the imaging surface I is displaced and adjusted, Since all the focus positions are on the imaging surface I, there are few problems.
　ところが、図１（ｂ）に示すように、第２レンズアレイＬＡ２が点線から実線で示す位置へと傾いた場合、光軸方向位置が殆ど変わらない個眼撮像光学系ＩＬ１を通過した被写体光ＬＢ１については、撮像面Ｉがピント位置に維持されるのに対し、個眼撮像光学系ＩＬ２，ＩＬ３を通過した被写体光ＬＢ２，ＬＢ３については、撮像面Ｉがピント位置からずれてしまうので、局所的にぼけた画像が得られることとなる。 However, as shown in FIG. 1B, when the second lens array LA2 is tilted from the dotted line to the position indicated by the solid line, the subject light LB1 that has passed through the single-eye imaging optical system IL1 whose optical axis direction position hardly changes. In contrast, the imaging plane I is maintained at the focus position, whereas the subject planes LB2 and LB3 that have passed through the single-lens imaging optical systems IL2 and IL3 are shifted locally from the focus position. A blurred image will be obtained.
　同様に、図１（ｃ）、（ｄ）に示すように、第２レンズアレイＬＡ２が点線から実線で示す位置へと反った場合、個眼撮像光学系ＩＬ１～ＩＬ３を通過した被写体光ＬＢ１～ＬＢ３のいずれも、撮像面Ｉがピント位置からずれてしまうので、全体的にぼけた画像が得られることとなる。このように、レンズアレイの傾きや反りが生じた場合、個眼撮像光学系を後から個々に調整することはできないため、何らかの対策が必要になる。 Similarly, as shown in FIGS. 1C and 1D, when the second lens array LA2 warps from the dotted line to the position indicated by the solid line, the subject light LB1˜ In any of LB3, since the imaging surface I shifts from the focus position, an entirely blurred image is obtained. In this way, when the lens array is tilted or warped, the single-eye imaging optical system cannot be individually adjusted later, and some countermeasure is required.
　このように、複眼撮像光学系の場合は、レンズアレイ全体に傾きや反りが発生した場合、各個眼撮像光学系ごとに空気間隔に違いが生じ結像点を変化させるから、その結果として、それぞれの個眼撮像系の性能バラつきが大きくなり良好な再構成画質を得ることが出来ないという問題がある。 In this way, in the case of a compound eye imaging optical system, if tilt or warp occurs in the entire lens array, the air gap differs for each single-eye imaging optical system and changes the imaging point. There is a problem that the performance variation of the single-eye imaging system becomes large and a good reconstructed image quality cannot be obtained.
　これに対し、特許文献２には、複数のレンズアレイを積層した複眼撮像光学系ユニットが開示されているが、上記課題に対する考慮はなく、さらに具体的なレンズ構成および形状の開示はされていない。 On the other hand, Patent Document 2 discloses a compound-eye imaging optical system unit in which a plurality of lens arrays are stacked. However, there is no consideration on the above-described problem, and no specific lens configuration and shape are disclosed. .
　本発明は、このような課題点に鑑みてなされたものであり、超低背でかつ高画質を有する複眼撮像光学系において、レンズアレイの傾きや反りにより個眼撮像光学系ごとにレンズ間隔が変化しても、個眼撮像光学系間の結像面位置変化量のばらつきによる再構成画像の画質劣化を抑制することができ、レンズ間隔変化に対する結像面位置変化量が小さな複眼撮像光学系及びそれを用いた複眼撮像装置を提供することを目的とする。 The present invention has been made in view of such problems, and in a compound eye imaging optical system having an ultra-low profile and high image quality, the lens interval is different for each single-eye imaging optical system due to the tilt and warp of the lens array. Even if there is a change, it is possible to suppress deterioration in the image quality of the reconstructed image due to variations in the amount of change in image plane position between single-eye imaging optical systems, and a compound eye image pickup optical system that has a small amount of change in image plane position relative to lens spacing changes. And it aims at providing the compound eye imaging device using the same.
　上述した目的のうち少なくとも一つを実現するために、本発明の一側面を反映した複眼撮像光学系は、撮像素子の撮像面に複数の物体像を形成する複眼撮像光学系において、
　前記複眼撮像光学系は、物体側から順に、第１レンズアレイと、少なくとも1枚のレンズアレイを有する第２レンズアレイ群からなり、各レンズアレイは複数の個眼レンズを一体に形成してなり、前記第１レンズアレイと前記第２レンズアレイ群の個眼レンズを光軸方向に積層することで複数の個眼撮像光学系が形成され、該複数の個眼撮像光学系により複数の物体像がそれぞれ形成され、前記個眼撮像光学系の数は前記撮像素子に取得される前記物体像の数と等しくなっており、
　下記の条件式を満足することを特徴とする。
　－０．６＜ｆ／ｆ２＜１．５　　　（１）
但し、
　ｆ：前記個眼撮像光学系の全系焦点距離(ｍｍ)
　ｆ２：第２個眼レンズ群の焦点距離（前記第２レンズアレイ群が１枚のレンズアレイからなる場合には、そのレンズアレイの個眼レンズの焦点距離であり、前記第２レンズアレイ群が２枚以上のレンズアレイからなる場合には、各レンズアレイにおける光軸方向に積層された２枚以上の個眼レンズの合成焦点距離をいう）(ｍｍ)
　尚、焦点距離は、各個眼撮像光学系の設計中心波長で計算されるものとする。 In order to achieve at least one of the above-described objects, a compound eye imaging optical system reflecting one aspect of the present invention is a compound eye imaging optical system that forms a plurality of object images on an imaging surface of an imaging element.
The compound-eye imaging optical system includes, in order from the object side, a first lens array and a second lens array group having at least one lens array, and each lens array is formed by integrally forming a plurality of individual lenses. A plurality of single-lens imaging optical systems are formed by laminating the single-lens lenses of the first lens array and the second lens array group in the optical axis direction, and a plurality of object images are formed by the plurality of single-eye imaging optical systems. Are formed, and the number of the single-eye imaging optical systems is equal to the number of the object images acquired by the imaging device,
The following conditional expression is satisfied.
-0.6 <f / f2 <1.5 (1)
However,
f: Total focal length (mm) of the single-eye imaging optical system
f2: Focal length of the second lens group (if the second lens array group consists of a single lens array, this is the focal length of the single lens of the lens array, and the second lens array group In the case of two or more lens arrays, it means the combined focal length of two or more single-lens lenses stacked in the optical axis direction in each lens array) (mm)
The focal length is calculated at the design center wavelength of each single-eye imaging optical system.
　本発明者は、レンズ間隔変化に対するピント位置変化量（結像面位置の変化量）が小さい光学系について検討した。図２（ａ）で、焦点距離がｆ１の第１個眼レンズＬ１と、焦点距離がｆ２の第２個眼レンズＬ２の軸間距離をｄとする。ピント位置は、物体側から順に数えて最終のレンズ面から、焦点位置までの距離ｆＢで考える。 The present inventor has studied an optical system in which the amount of change in focus position (the amount of change in image plane position) with respect to the change in lens interval is small. In FIG. 2A, the distance between the axes of the first single-lens lens L1 having a focal length of f1 and the second single-eye lens L2 having a focal length of f2 is defined as d. The focus position is considered as a distance fB from the final lens surface to the focal position, counting in order from the object side.
　ここで、レンズアレイの反りや傾きにより、図２（ｂ）に示すように、第１個眼レンズＬ１と第２個眼レンズＬ２の軸間距離がｔだけ変化したものとする。この軸間距離の変化が生じても、ピント位置の変化量を抑えるには、ｆＢのｔに対する変化量ｄ（ｆＢ）／ｄｔが小さければ良い。 Here, it is assumed that the distance between the axes of the first eye lens L1 and the second eye lens L2 is changed by t as shown in FIG. Even if the change in the distance between the axes occurs, the change amount d (fB) / dt of fB with respect to t may be small in order to suppress the change amount of the focus position.
　図２（ａ）に示す設計状態での個眼撮像光学系の全系の焦点距離をｆとすると、
　ｆ＝（ｆ１・ｆ２）／（ｆ１＋ｆ２－ｄ）　　　（６）
で表せる。一方、図２（ｂ）に示すように、第１個眼レンズＬ１と第２個眼レンズＬ２の軸間距離がｔだけ変化した状態での、個眼撮像光学系の合成焦点距離をｆ’とすると、
　ｆ’＝（ｆ１・ｆ２）／（ｆ１＋ｆ２－（ｄ＋ｔ））　　　（７）
で表せる。又、このとき第２主点までの距離Ｈ’は、以下の式で表せる。
　Ｈ’＝－ｆ'（ｄ＋ｔ）／ｆ１　　　（８）
　更に、第１個眼レンズＬ１と第２個眼レンズＬ２の軸間距離がｔだけ変化した個眼撮像光学系における最終のレンズ面から焦点位置までの距離ｆＢは、以下の式で表せる。
　ｆＢ＝ｆ’＋Ｈ’
　　　＝（ｆ２（ｆ１－（ｄ＋ｔ））／（ｆ１＋ｆ２－（ｄ＋ｔ））　　　（９）
　（９）式をｔで微分すると、以下のようになる。
　ｄ（ｆＢ）／ｄｔ＝－ｆ２2／（ｆ１＋ｆ２－（ｄ＋ｔ））2　　　（１０） If the focal length of the entire system of the single-eye imaging optical system in the design state shown in FIG.
f = (f1 · f2) / (f1 + f2-d) (6)
It can be expressed as On the other hand, as shown in FIG. 2B, the combined focal length of the single-eye imaging optical system in a state where the interaxial distance between the first single-eye lens L1 and the second single-eye lens L2 is changed by t is f ′. Then,
f ′ = (f1 · f2) / (f1 + f2− (d + t)) (7)
It can be expressed as At this time, the distance H ′ to the second principal point can be expressed by the following equation.
H ′ = − f ′ (d + t) / f1 (8)
Further, the distance fB from the final lens surface to the focal position in the single-eye imaging optical system in which the distance between the axes of the first single-lens L1 and the second single-lens L2 has changed by t can be expressed by the following equation.
fB = f ′ + H ′
= (F2 (f1- (d + t)) / (f1 + f2- (d + t)) (9)
When the equation (9) is differentiated by t, it becomes as follows.
d (fB) / dt = −f2 2 / (f1 + f2- (d + t)) 2 (10)
　式（１０）によれば、ｄ（ｆＢ）／ｄｔはｆ２に対して放物線状に変化し極値を持つから、あるｆ２の範囲でｄ（ｆＢ）／ｄｔの値を小さく抑えることができる、すなわちｔが変化してもｆＢの変化量を抑えることができることが分かる。 According to equation (10), d (fB) / dt changes in a parabolic shape with respect to f2 and has an extreme value, so that the value of d (fB) / dt can be kept small within a certain f2 range. That is, it can be seen that the amount of change in fB can be suppressed even if t changes.
　図３は、横軸にｆ／ｆ２をとり、縦軸にｄ（ｆＢ）／ｄｔをとって、式（１０）の値をプロットして示すグラフである。ｄ（ｆＢ）／ｄｔを０とすることは理想であるが、必ずしも０にする必要はなく、－２．０以上に抑えることで、実用上ぼけの目立たない画像を得ることができる。このとき、ｆ／ｆ２の範囲は－０．６～２となる。 FIG. 3 is a graph plotting the value of equation (10) with f / f2 on the horizontal axis and d (fB) / dt on the vertical axis. It is ideal to set d (fB) / dt to 0, but it is not always necessary to set it to 0, and an image that is practically inconspicuous can be obtained by suppressing it to −2.0 or more. At this time, the range of f / f2 is −0.6 to 2.
　本複眼撮像光学系によれば、条件式（１）を満たすように、第２個眼レンズ群の焦点距離を長くすることで、各個眼撮像光学系のレンズ間隔変化に対する結像面位置変動を小さくでき、個眼撮像光学系間の性能バラつきを低減できる。より具体的には、条件式（１）の値が上限値を下回ることで、第２個眼レンズ群が正の屈折力を有するとき（ｆ／ｆ２＞０）、レンズ間隔の変化に対する結像面位置変動を抑えることができ、良好な画質の再構成画像を得ることが出来る。一方、条件式（１）の値が下限値を上回ることで、第２個眼レンズ群が負の屈折力を有するとき（ｆ／ｆ２＜０）、レンズ間隔の変化に対する結像面位置変動を抑えることができ、良好な画質の再構成画像を得ることが出来る。 According to this compound-eye imaging optical system, by changing the focal length of the second single-lens lens group so as to satisfy the conditional expression (1), the imaging plane position variation with respect to the lens interval change of each single-eye imaging optical system is reduced. It is possible to reduce the size, and the performance variation between the single-eye imaging optical systems can be reduced. More specifically, when the value of the conditional expression (1) is less than the upper limit value and the second lens unit has a positive refractive power (f / f2> 0), imaging with respect to a change in the lens interval is performed. Surface position variation can be suppressed, and a reconstructed image with good image quality can be obtained. On the other hand, when the value of conditional expression (1) exceeds the lower limit, when the second lens unit has a negative refractive power (f / f2 <0), the image plane position variation with respect to the change in the lens interval is reduced. Therefore, a reconstructed image with good image quality can be obtained.
　本複眼撮像装置は、上述の複眼撮像光学系を有することを特徴とする。 This compound-eye imaging device has the above-described compound-eye imaging optical system.
　本発明によれば、レンズアレイの傾きや反りにより個眼撮像光学系ごとにレンズ間隔が変化しても、個眼撮像光学系間の結像面位置変化量のばらつきによる再構成画像の画質劣化を抑制することができ、レンズ間隔変化に対する結像面位置変化量が小さな複眼撮像光学系及びそれを用いた複眼撮像装置を提供することができる。 According to the present invention, even if the lens interval is changed for each single-lens imaging optical system due to the tilt or warp of the lens array, the image quality of the reconstructed image is deteriorated due to variation in the image plane position change amount between the single-lens imaging optical systems. It is possible to provide a compound-eye imaging optical system in which the amount of change in the image plane position relative to the lens interval change is small, and a compound-eye imaging device using the same.
（ａ）～（ｄ）は複眼光学撮像系におけるレンズアレイの傾きや反り等の変形の例を説明するための図である。(A)-(d) is a figure for demonstrating the example of deformation | transformation of the inclination of a lens array, a curvature, etc. in a compound eye optical imaging system. （ａ）（ｂ）は、個眼レンズの焦点距離の関係を示す図である。(A) (b) is a figure which shows the relationship of the focal distance of a single lens. 横軸にｆ／ｆ２をとり、縦軸にｄ（ｆＢ）／ｄｔをとって式（１０）の値を示すグラフである。It is a graph which shows the value of Formula (10) by taking f / f2 on a horizontal axis and taking d (fB) / dt on a vertical axis | shaft. 本実施形態による撮像装置を模式的に示す図である。It is a figure which shows typically the imaging device by this embodiment. 図４の複眼撮像光学系の断面図である。It is sectional drawing of the compound eye imaging optical system of FIG. 実施例１の複眼撮像系における、光軸方向に積層した一組の個眼レンズ（個眼撮像光学系）の断面図である。FIG. 3 is a cross-sectional view of a pair of single-lens lenses (single-eye imaging optical system) stacked in the optical axis direction in the compound-eye imaging system of Example 1; 実施例１の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 4 is an aberration diagram of Example 1 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例２の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 2. 実施例２の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 2. 実施例２の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 2. 実施例２の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例２の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例２の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 6 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例３の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 3. 実施例３の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 3. 実施例３の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 3. 実施例３の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 10 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例３の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 10 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例３の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 10 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例４の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 6 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 4; 実施例４の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 6 is an aberration diagram of Example 4 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例５の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 10 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 5. 実施例５の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 6 is an aberration diagram of Example 5 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例６の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 12 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 6. 実施例６の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 6 is an aberration diagram of Example 6 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). 実施例７の複眼撮像系における、光軸方向に積層した一組の個眼レンズ個眼撮像光学系）の断面図である。FIG. 10 is a cross-sectional view of a pair of single-lens single-lens imaging optical systems stacked in the optical axis direction in the compound-eye imaging system of Example 7. 実施例７の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。FIG. 10 is an aberration diagram of Example 7 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)).
　以下、本発明の実施形態による複眼撮像光学系とそれを用いた撮像装置等を説明する。複眼撮像光学系は、１つの撮像素子に対して複数のレンズ系がアレイ状に配置された光学系であり、各レンズ系が同一被写体の撮像を行う超解像タイプと、各レンズ系が異なる視野の撮像を行う視野分割タイプと、に通常分けられる。本実施形態では、同一被写体の複数の低解像度画像を画像処理にて合成し、1枚の高解像度画像を出力する超解像タイプにかかる複眼撮像光学系について説明する。 Hereinafter, a compound eye imaging optical system according to an embodiment of the present invention and an imaging apparatus using the same will be described. The compound-eye imaging optical system is an optical system in which a plurality of lens systems are arranged in an array with respect to one imaging device, and each lens system is different from a super-resolution type in which each lens system images the same subject. It is usually divided into a visual field division type for imaging a visual field. In the present embodiment, a multi-eye imaging optical system according to a super-resolution type that combines a plurality of low-resolution images of the same subject by image processing and outputs one high-resolution image will be described.
　図４に本実施形態による撮像装置を模式的に示す。図４に示すように、撮像装置ＤＵは、撮像ユニットＬＵ，画像処理部１，演算部２，メモリー３等を有している。そして、撮像ユニットＬＵは、１つの撮像素子ＳＲと、その撮像素子ＳＲに対して同一被写体の複数の像を結像する複眼撮像光学系ＬＨと、を有している。撮像素子ＳＲとしては、例えば複数の画素を有するＣＣＤ（Charged Coupled Device）型イメージセンサまたはＣＭＯＳ（Complementary Metal Oxide Semiconductor）型イメージセンサ等の固体撮像素子が用いられる。撮像素子ＳＲの光電変換部である受光面ＳＳ上には、被写体の光学像が形成されるように複眼撮像光学系ＬＨが設けられているので、複眼撮像光学系ＬＨによって形成された光学像は、撮像素子ＳＲによって電気的な信号に変換される。 FIG. 4 schematically shows the imaging apparatus according to the present embodiment. As illustrated in FIG. 4, the imaging device DU includes an imaging unit LU, an image processing unit 1, a calculation unit 2, a memory 3, and the like. The imaging unit LU includes one imaging element SR and a compound-eye imaging optical system LH that forms a plurality of images of the same subject on the imaging element SR. As the image sensor SR, for example, a solid-state image sensor such as a CCD (Charged Coupled Device) type image sensor or a CMOS (Complementary Metal Oxide Semiconductor) type image sensor having a plurality of pixels is used. Since the compound-eye imaging optical system LH is provided on the light-receiving surface SS that is the photoelectric conversion unit of the imaging element SR so that an optical image of the subject is formed, the optical image formed by the compound-eye imaging optical system LH is Then, it is converted into an electrical signal by the image sensor SR.
　図５は、図４の複眼撮像光学系ＬＨの拡大断面図である。複眼撮像光学系ＬＨは、物体側より順に、第１レンズアレイＬＡ１、第２レンズアレイＬＡ２からなる。各レンズアレイは、所謂ウエハレンズである。第１レンズアレイＬＡ１は、１枚の第１平行平板ＰＰ１の物体側に複数の第１物体側レンズ部Ｌ１ａを形成し、像側に複数の第１像側レンズ部Ｌ１ｂを成形により形成している。第１物体側レンズ部Ｌ１ａと、第１平行平板ＰＰ１と、第１像側レンズ部Ｌ１ｂとで、第１個眼レンズＩＬ１を構成する。 FIG. 5 is an enlarged cross-sectional view of the compound eye imaging optical system LH of FIG. The compound-eye imaging optical system LH includes a first lens array LA1 and a second lens array LA2 in order from the object side. Each lens array is a so-called wafer lens. The first lens array LA1 is formed by forming a plurality of first object side lens portions L1a on the object side of one first parallel plate PP1 and forming a plurality of first image side lens portions L1b on the image side by molding. Yes. The first object-side lens portion L1a, the first parallel plate PP1, and the first image-side lens portion L1b constitute a first single-lens lens IL1.
　又、第２レンズアレイＬＡ２は、１枚の第２平行平板ＰＰ２の物体側に複数の第２物体側レンズ部Ｌ２ａを形成し、像側に複数の第２像側レンズ部Ｌ２ｂを成形により形成している。第２物体側レンズ部Ｌ２ａと、第２平行平板ＰＰ２と、第２像側レンズ部Ｌ２ｂとで、第２個眼レンズ群ＩＬ２を構成する。光軸方向に積層された第１個眼レンズＩＬ１と第２個眼レンズ群ＩＬ２とで、個眼撮像光学系を構成する。 In the second lens array LA2, a plurality of second object side lens portions L2a are formed on the object side of one second parallel flat plate PP2, and a plurality of second image side lens portions L2b are formed on the image side by molding. is doing. The second object-side lens portion L2a, the second parallel plate PP2, and the second image-side lens portion L2b constitute a second single-eye lens group IL2. The first eye lens IL1 and the second eye lens group IL2 stacked in the optical axis direction constitute a single eye imaging optical system.
　個眼レンズの数は、撮像素子ＳＲの撮像面ＳＳ上に形成される物体像（個眼像という）の数と等しくさせてなる。つまり、光軸方向に積層された個眼レンズを通過した光線が、それぞれ撮像面ＳＳ上で１つの像を形成する。尚、Ｓは、第１物体側レンズ部Ｌ１ａの周囲に形成された開口絞りであり、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板である。個眼撮像光学系の全系焦点距離をｆ(ｍｍ)、第２個眼レンズ群の焦点距離ｆ２（ｍｍ）とすると、以下の式が成立する。
　－０．６＜ｆ／ｆ２＜１．５　　　（１） The number of single lenses is made equal to the number of object images (referred to as single images) formed on the imaging surface SS of the image sensor SR. That is, the light rays that have passed through the single-lens lenses stacked in the optical axis direction form one image on the imaging surface SS. Note that S is an aperture stop formed around the first object side lens portion L1a, and F is a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state image sensor, and the like. When the total focal length of the single-eye imaging optical system is f (mm) and the focal length f2 (mm) of the second single-lens lens group, the following equation is established.
-0.6 <f / f2 <1.5 (1)
　第１レンズアレイＬＡ１と第２レンズアレイＬＡ２のうち少なくとも一方を、一体成形しても良い。又、１つのレンズアレイ内における個眼レンズが、少なくとも３つ以上の異なる波長分布に対して各々設計され異なる光学特性を有するようにしても良い。又、１つのレンズアレイ内における個眼レンズが、異なる複数の波長分布に応じた透過率を持った複数のカラーフィルタと組み合わされるようにしても良い。 At least one of the first lens array LA1 and the second lens array LA2 may be integrally molded. Further, the single lens in one lens array may be designed for at least three different wavelength distributions and have different optical characteristics. Further, the single lens in one lens array may be combined with a plurality of color filters having transmittances corresponding to a plurality of different wavelength distributions.
　図４に示すように、画像処理部１は、複眼撮像光学系ＬＨにより撮像素子ＳＲの撮像面ＳＳ上に形成された複数の個眼像Ｚｎ（ｎ＝１，２，３，…）に応じた信号を合成処理し、１枚の個眼合成画像ＭＬを出力することができる。個眼合成画像ＭＬは、演算部２で圧縮されてメモリー３に記憶される。 As shown in FIG. 4, the image processing unit 1 responds to a plurality of single-eye images Zn (n = 1, 2, 3,...) Formed on the imaging surface SS of the imaging element SR by the compound-eye imaging optical system LH. By combining the received signals, one single-eye combined image ML can be output. The single-eye composite image ML is compressed by the calculation unit 2 and stored in the memory 3.
　以下、好ましい実施態様についてさらに説明する。 Hereinafter, preferred embodiments will be further described.
　上記複眼撮像光学系において、前記第１レンズアレイの個眼レンズである第１個眼レンズは、正の屈折力を有することが好ましい。第１個眼レンズが正の屈折力を有するようにすることで、個眼撮像光学系の全長を短くできる。 In the above compound-eye imaging optical system, it is preferable that the first monocular lens that is the monocular lens of the first lens array has a positive refractive power. By making the first single-lens lens have positive refractive power, the total length of the single-eye imaging optical system can be shortened.
　また、前記第１個眼レンズは、下記の条件式を満足することが好ましい。
　０．７＜ｆ１／ｆ＜１．５　　　（２）
但し、
ｆ１：第１個眼レンズの焦点距離(ｍｍ) Moreover, it is preferable that the first single-eye lens satisfies the following conditional expression.
0.7 <f1 / f <1.5 (2)
However,
f1: Focal length of the first single-lens lens (mm)
　条件式（２）を満たすことで、第1個眼レンズの焦点距離を個眼撮像光学系全系の焦点距離に近づけて、第２個眼レンズ群の焦点距離を長くすることができ、レンズ間隔の変化に対する個眼撮像光学系間の性能バラつき抑制効果をより高めることができる。また、第1個眼レンズの焦点距離を小さくすることで全長短縮が期待できる。具体的には、条件式（２）の値が上限値を下回ることで、第1個眼レンズの焦点距離が小さくなり、主点が前進し、光学全長を短くすることができる。また、第1個眼レンズの焦点距離が小さくなることで、画角を広角化できる。一方、条件式（２）の値が下限値を上回ることで、第２個眼レンズの焦点距離が大きくなり、レンズ間隔の変化に対する結像面位置変動を抑えることができ、良好な画質の再構成画像を得ることが出来る。 By satisfying conditional expression (2), the focal length of the first single-lens lens can be made closer to the focal length of the entire single-lens imaging optical system, and the focal length of the second single-lens lens group can be increased. It is possible to further increase the performance variation suppressing effect between the single-eye imaging optical systems with respect to the change in the interval. Moreover, shortening the overall length can be expected by reducing the focal length of the first single-lens lens. Specifically, when the value of conditional expression (2) is less than the upper limit value, the focal length of the first single-lens lens is reduced, the principal point is advanced, and the optical total length can be shortened. In addition, the angle of view can be widened by reducing the focal length of the first lens. On the other hand, when the value of conditional expression (2) exceeds the lower limit value, the focal length of the second eye lens increases, and fluctuations in the image plane position due to changes in the lens interval can be suppressed. A configuration image can be obtained.
　また、前記第１レンズアレイの個眼レンズである第１個眼レンズの物体側面は、物体側に凸面を有することが好ましい。第１個眼レンズの物体側面が物体側に凸面を有することで、個眼撮像光学系の全長を短くできる。 Further, it is preferable that the object side surface of the first single-lens lens which is the single-lens of the first lens array has a convex surface on the object side. Since the object side surface of the first monocular lens has a convex surface on the object side, the total length of the monocular imaging optical system can be shortened.
　また、前記第１個眼レンズは、下記の条件式を満足することが好ましい。
　－５．０＜ｇ１＜－０．５　　　（３）
但し、
ｇ１：前記第１個眼レンズのシェーピングファクター
　　（ｇ１＝（Ｒ１＋Ｒ２）／（Ｒ１－Ｒ２））
Ｒ１：前記第１個眼レンズの物体側面の曲率半径(ｍｍ)
Ｒ２：前記第１個眼レンズの像側面の曲率半径(ｍｍ) Moreover, it is preferable that the first single-eye lens satisfies the following conditional expression.
-5.0 <g1 <-0.5 (3)
However,
g1: Shaping factor of the first single-lens lens (g1 = (R1 + R2) / (R1-R2))
R1: Curvature radius of object side surface of the first single-lens lens (mm)
R2: radius of curvature of the image side surface of the first single-lens lens (mm)
　条件式（３）を満たすことで、複眼撮像光学系の光学性能を向上させることができるとともに、第１レンズアレイの成形性を向上できる。具体的には、条件式（３）の値が上限値を下回ることで、第１個眼レンズの球面収差を抑制することができ、良好な画質の再構成画像を得ることが出来る。また、主点を前進させ、個眼撮像光学系の光学全長を短くすることもできる。一方、条件式（３）の値が下限値を上回ることで、第１個眼レンズの曲率が大きくなり過ぎず、そのレンズ面への光線入射角を小さくすることで、コマ収差などの発生を抑制できる。また、第１個眼レンズを樹脂の射出成形で製造する場合、曲率を大きくし過ぎないことで、樹脂の流動性を確保し、成形精度を向上できる。 By satisfying conditional expression (3), the optical performance of the compound-eye imaging optical system can be improved, and the moldability of the first lens array can be improved. Specifically, when the value of conditional expression (3) is less than the upper limit value, spherical aberration of the first single-eye lens can be suppressed, and a reconstructed image with good image quality can be obtained. Further, the principal point can be advanced to shorten the optical total length of the single-eye imaging optical system. On the other hand, when the value of conditional expression (3) exceeds the lower limit value, the curvature of the first single-lens lens does not become too large, and the incidence of coma and the like can be reduced by reducing the light incident angle on the lens surface. Can be suppressed. Moreover, when manufacturing a 1st single lens by injection molding of resin, the fluidity | liquidity of resin can be ensured and a molding precision can be improved by not making curvature too large.
　また、前記第２個眼レンズ群における像側に最も近い面の周辺部は、像側に凸の面形状を有することが好ましい。第２個眼レンズ群の最終面の周囲が、像側に凸の面形状を有することで、高像高の光線射出角度が減少し、撮像面に対するテレセントリック性が良好になる他、隣接する個眼撮像エリアへの光線侵入（クロストーク）の抑制効果がある。 Further, it is preferable that the peripheral portion of the surface closest to the image side in the second single-eye lens group has a convex shape on the image side. Since the periphery of the final surface of the second binocular lens group has a convex surface shape on the image side, the light emission angle at a high image height is reduced, and the telecentricity with respect to the imaging surface is improved. There is an effect of suppressing ray intrusion (crosstalk) into the eye imaging area.
　また、下記の条件式を満足することを特徴とする。
　０．０５＜ｄ２／ｆ＜０．２５　　　（４）
但し、
ｄ２：前記第１レンズアレイの個眼レンズである第１個眼レンズの像側面と、前記第２個眼レンズ群の最も物体側の面との間隔(ｍｍ) Further, the following conditional expression is satisfied.
0.05 <d2 / f <0.25 (4)
However,
d2: the distance (mm) between the image side surface of the first single-lens lens, which is the single-lens lens of the first lens array, and the most object-side surface of the second single-lens group
　複眼撮像光学系の超薄型化に対応するためには、全長を短縮しながらも、収差補正のための光学面形状の自由度の確保は重要である。そこで、条件式（４）の値が上限値を下回ることで、主点を前進させ、個眼撮像光学系の光学全長を短くすることができる。一方、条件式（４）の値が下限値を上回ることで、個眼レンズ間隔をある程度確保することで、光学面形状の自由度が向上し、収差補正能力を増大させることが出来る。望ましくは、以下の条件式を満足することである。
　０．１＜ｄ２／ｆ＜０．１９　　　（４’） In order to cope with the ultra-thinning of the compound-eye imaging optical system, it is important to secure the degree of freedom of the optical surface shape for aberration correction while shortening the overall length. Therefore, when the value of conditional expression (4) is below the upper limit value, the principal point can be advanced and the optical total length of the single-eye imaging optical system can be shortened. On the other hand, when the value of conditional expression (4) exceeds the lower limit value, the degree of freedom of the optical surface shape can be improved and the aberration correction capability can be increased by securing a certain distance between the single lenses. Desirably, the following conditional expression is satisfied.
0.1 <d2 / f <0.19 (4 ′)
　また、下記の条件式を満足することが好ましい。
　０≦Δ（ｆ／ｆ２）ｍａｘ＜０．６　　　（５）
但し、
Δ（ｆ／ｆ２）ｍａｘ：各個眼撮像光学系における（ｆ／ｆ２）の差の最大値の絶対値 Moreover, it is preferable that the following conditional expressions are satisfied.
0 ≦ Δ (f / f2) max <0.6 (5)
However,
Δ (f / f2) max: absolute value of the maximum value of the difference of (f / f2) in each single-eye imaging optical system
　各個眼撮像光学系における第２個眼レンズ群の焦点距離ｆ２は、条件式（１）を満たすことが前提である。ここで、全波長域に対して共通に設計された個眼撮像光学系それぞれにおける第２個眼レンズ群の焦点距離ｆ２の差は、設計上ゼロである。ところが、各個眼撮像光学系をグループ分けし、異なる波長分布（色）毎に最適設計する仕様がある。このような仕様でも、焦点距離ｆ２を互いにある程度近い値とすることが望ましい。そこで、条件式（５）の値が上限値を下回るようにすることで、仕様にかかわらず個眼撮像光学系同士の第２個眼レンズ群の焦点距離ｆ２の差が小さくなり、レンズ間隔の変化に対して、個眼撮像光学系ごとの結像面位置変動バラつきを抑えることができ、良好な画質の再構成画像を得ることが出来る。望ましくは、以下の条件式を満足することである。
　０　≦Δ（ｆ／ｆ２）ｍａｘ　　＜　０．０５ It is a premise that the focal length f2 of the second single-lens lens group in each single-eye imaging optical system satisfies the conditional expression (1). Here, the difference in the focal length f2 of the second single-lens lens group in each single-eye imaging optical system designed in common for all wavelength ranges is zero in design. However, there is a specification in which individual eye imaging optical systems are grouped and optimally designed for different wavelength distributions (colors). Even in such a specification, it is desirable that the focal lengths f2 be close to each other to some extent. Therefore, by making the value of conditional expression (5) below the upper limit value, the difference in the focal length f2 of the second single-lens lens group between the single-eye imaging optical systems becomes small regardless of the specifications, and the lens interval With respect to the change, it is possible to suppress variation in the image plane position variation for each single-lens imaging optical system, and a reconstructed image with good image quality can be obtained. Desirably, the following conditional expression is satisfied.
0 ≦ Δ (f / f2) max <0.05
　ここで、例えば異なる３つの波長分布α（λ）、β（λ）、γ（λ）に対して設計された各個眼撮像光学系のそれぞれの基準波長で焦点距離を、ｆα、ｆβ、ｆγとし、第２個眼レンズ群の焦点距離を、ｆ２α、ｆ２β、ｆ２γとすると、｜ｆα／ｆ２α－ｆβ／ｆ２β｜、｜ｆα／ｆ２α－ｆγ／ｆ２γ｜、｜ｆβ／ｆ２β－ｆγ／ｆ２γ｜の内、最大値となるものをΔ（ｆ／ｆ２）ｍａｘとする。 Here, for example, the focal lengths at the respective reference wavelengths of the single-eye imaging optical systems designed for three different wavelength distributions α (λ), β (λ), and γ (λ) are fα, fβ, and fγ. If the focal lengths of the second lens unit are f2α, f2β, and f2γ, then | fα / f2α-fβ / f2β |, | fα / f2α-fγ / f2γ |, | fβ / f2β-fγ / f2γ | Among them, the maximum value is Δ (f / f2) max.
　次に、上述した実施形態に好適な実施例について説明する。以下に示す実施例において、複眼撮像光学系は共通するから、その仕様を説明している。
Ｆｎｏ：Ｆナンバー
ω：画角（゜）
Ｙ：像高（ｍｍ）
ｆ：全系焦点距離（ｍｍ）
ｆＢ：バックフォーカス（ｍｍ）
Ｒ：曲率半径（ｍｍ）
ｄ：軸上面間隔（ｍｍ）
ｎｄ：レンズ材料のｄ線に対する屈折率
νｄ：レンズ材料のアッベ数 Next, examples suitable for the above-described embodiment will be described. In the following embodiments, the compound eye imaging optical system is common, so its specifications are described.
Fno: F number ω: Angle of view (°)
Y: Image height (mm)
f: Total focal length (mm)
fB: Back focus (mm)
R: radius of curvature (mm)
d: Shaft upper surface distance (mm)
nd: refractive index of lens material with respect to d-line νd: Abbe number of lens material
　各実施例において、Ｓは面番号であり、非球面係数が記載された面が非球面形状を有する面であり、非球面の形状は、面の頂点を原点とし、光軸方向にZ軸をとり、光軸と垂直方向の高さをｈとして以下の「数１」で表す。 In each embodiment, S is a surface number, and the surface on which the aspheric coefficient is described is a surface having an aspheric shape, and the aspheric shape has the vertex of the surface as the origin and the Z axis in the optical axis direction. The height in the direction perpendicular to the optical axis is represented by the following “Equation 1”.
Figure JPOXMLDOC01-appb-M000001
ただし、
ｚ：光軸に平行な面のサグ量
ｈ：光軸に垂直な方向の高さ
Ｒ：曲率半径
ｋ：コーニック係数（円錐定数）
Ａi：ｉ次の非球面係数
Figure JPOXMLDOC01-appb-M000001
However,
z: sag amount of a plane parallel to the optical axis h: height in a direction perpendicular to the optical axis R: radius of curvature k: conic coefficient (conical constant)
A i : i-th order aspheric coefficient
（実施例１）
　実施例１のレンズデータを表１に示す。実施例１の設計中心波長は、５４６．１ｎｍである。なお、これ以降（表のレンズデータを含む）において、１０のべき乗数（たとえば２．５×１０-02）を、Ｅ（たとえば２．５Ｅ－０２）を用いて表すものとする。図６は、実施例１の個眼撮像光学系の断面図である。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ群である。第２個眼レンズ群ＩＬ２の最も像側の面の周辺部は、像側に凸の面形状を有する。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図７は実施例１の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。ここで、球面収差図において、実線は波長６５６ｎｍの光線、点線は波長５４６ｎｍの光線、一点鎖線は波長４０５ｎｍの光線に対する球面収差量をそれぞれ表す。又、非点収差・像面歪曲図において、実線はサジタル方向、点線はメリジオナル方向を表す（以下同じ）。 (Example 1)
Table 1 shows lens data of Example 1. The design center wavelength of Example 1 is 546.1 nm. In the following (including the lens data in the table), a power of 10 (for example, 2.5 × 10 −02 ) is expressed using E (for example, 2.5E-02). FIG. 6 is a cross-sectional view of the single-eye imaging optical system of Example 1. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, and IL2 is a second monocular lens group. The peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIG. 7 is an aberration diagram of Example 1 (spherical aberration (a), astigmatism / field curvature (b), distortion aberration (c)). Here, in the spherical aberration diagram, the solid line represents the ray of wavelength 656 nm, the dotted line represents the ray of wavelength 546 nm, and the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm. In the astigmatism / field distortion diagram, the solid line represents the sagittal direction, and the dotted line represents the meridional direction (the same applies hereinafter).
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（実施例２）
　実施例２のレンズデータを表２Ａ～２Ｃに示す。図８～１０は、実施例２の個眼撮像光学系の断面図である。本実施例では、第１レンズアレイ、第２レンズアレイがそれぞれ一体的に形成されていて（実施例３，４、５、７において同じ）、更に個眼撮像光学系を波長毎に設計しており、表２Ａ、図８に示す個眼撮像光学系では、赤色領域に対して最適設計を行った例であり、その設計中心波長は、６２２．０ｎｍである。又、表２Ｂ、図９に示す個眼撮像光学系では、緑色領域に対して最適設計を行った例であり、その設計中心波長は、５４４．０ｎｍである。更に、表２Ｃ、図１０に示す個眼撮像光学系では、青色領域に対して最適設計を行った例であり、その設計中心波長は、４５８．０ｎｍである。これらの個眼撮像光学系は３つを１セットとし、対応する色のカラーフィルタとともに用いることで、１つの物体像を形成できる。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ群である。第２個眼レンズ群ＩＬ２の最も像側の面の周辺部は、像側に凸の面形状を有する。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図１１～１３は、図８～１０の個眼撮像光学系にそれぞれ対応する収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。 (Example 2)
Lens data of Example 2 are shown in Tables 2A to 2C. 8 to 10 are sectional views of the single-eye imaging optical system according to the second embodiment. In this embodiment, the first lens array and the second lens array are integrally formed (the same applies to the third, fourth, fifth, and seventh embodiments), and the single-eye imaging optical system is designed for each wavelength. The single-eye imaging optical system shown in Table 2A and FIG. 8 is an example in which the optimum design is performed for the red region, and the design center wavelength is 622.0 nm. The single-eye imaging optical system shown in Table 2B and FIG. 9 is an example in which the optimum design is performed for the green region, and the design center wavelength is 544.0 nm. Further, the single-eye imaging optical system shown in Table 2C and FIG. 10 is an example in which the optimum design is performed for the blue region, and the design center wavelength is 458.0 nm. These single-eye imaging optical systems can be formed as a set of three and used together with a corresponding color filter to form one object image. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, and IL2 is a second monocular lens group. The peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIGS. 11 to 13 are aberration diagrams (spherical aberration (a), astigmatism / field curvature (b), distortion aberration (c)) respectively corresponding to the single-eye imaging optical systems of FIGS.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
（実施例３）
　実施例３のレンズデータを表３Ａ～３Ｃに示す。図１４～１６は、実施例３の個眼撮像光学系の断面図である。本実施例では、第１レンズアレイ、第２レンズアレイがそれぞれ一体的に形成されていて、更に個眼撮像光学系を波長毎に設計しており、表３Ａ、図１４に示す個眼撮像光学系では、赤色領域に対して最適設計を行った例であり、その設計中心波長は、６２２．０ｎｍである。又、表３Ｂ、図１５に示す個眼撮像光学系では、緑色領域に対して最適設計を行った例であり、その設計中心波長は、５４４．０ｎｍである。更に、表３Ｃ、図１６に示す個眼撮像光学系では、青色領域に対して最適設計を行った例であり、その設計中心波長は、４５８．０ｎｍである。これらの個眼撮像光学系は３つを１セットとし、対応する色のカラーフィルタとともに用いることで、１つの物体像を形成できる。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ群である。第２個眼レンズ群ＩＬ２の最も像側の面の周辺部は、像側に凸の面形状を有する。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図１７～１９は、図１４～１６の個眼撮像光学系にそれぞれ対応する収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。 (Example 3)
Lens data of Example 3 are shown in Tables 3A to 3C. 14 to 16 are sectional views of the single-eye imaging optical system according to the third embodiment. In this embodiment, the first lens array and the second lens array are integrally formed, and the single-eye imaging optical system is designed for each wavelength. The single-eye imaging optics shown in Table 3A and FIG. The system is an example in which the optimum design is performed for the red region, and the design center wavelength is 622.0 nm. The single-eye imaging optical system shown in Table 3B and FIG. 15 is an example in which the optimum design is performed for the green region, and the design center wavelength is 544.0 nm. Further, the single-eye imaging optical system shown in Table 3C and FIG. 16 is an example in which the optimum design is performed for the blue region, and the design center wavelength is 458.0 nm. These single-eye imaging optical systems can be formed as a set of three and used together with a corresponding color filter to form one object image. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, and IL2 is a second monocular lens group. The peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIGS. 17 to 19 are aberration diagrams (spherical aberration (a), astigmatism / field curvature (b), distortion aberration (c)) corresponding to the single-eye imaging optical systems of FIGS. 14 to 16, respectively.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
（実施例４）
　実施例４レンズデータを表４に示す。実施例４の設計中心波長は、５３０．０ｎｍである。図２０は、実施例４の個眼撮像光学系の断面図である。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ，ＩＬ３は第３個眼レンズである。ＩＬ２，ＩＬ３とで第２個眼レンズ群を構成する。第３個眼レンズＩＬ３の最も像側の面の周辺部は、像側に凸の面形状を有する。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図２１は実施例４の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。ここで、球面収差図において、実線は波長５７０ｎｍの光線、点線は波長５３０ｎｍの光線、一点鎖線は波長４９０ｎｍの光線に対する球面収差量をそれぞれ表す。 Example 4
Table 4 shows lens data of Example 4. The design center wavelength of Example 4 is 530.0 nm. FIG. 20 is a cross-sectional view of the single-eye imaging optical system of Example 4. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, IL2 is a second monocular lens, and IL3 is a third monocular lens. IL2 and IL3 constitute a second monocular lens group. The peripheral portion of the surface closest to the image side of the third eye lens IL3 has a convex shape on the image side. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIG. 21 is an aberration diagram of Example 4 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). Here, in the spherical aberration diagram, the solid line represents the light beam having a wavelength of 570 nm, the dotted line represents the light beam having a wavelength of 530 nm, and the alternate long and short dash line represents the amount of spherical aberration with respect to the light beam having a wavelength of 490 nm.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
（実施例５）
　実施例５のレンズデータを表５に示す。実施例５の設計中心波長は、５４６．１ｎｍである。図２２は、実施例５の個眼撮像光学系の断面図である。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ群である。第２個眼レンズ群ＩＬ２の最も像側の面の周辺部は、像側に凸の面形状を有する。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図２３は実施例５の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。ここで、球面収差図において、実線は波長６５６ｎｍの光線、点線は波長５４６ｎｍの光線、一点鎖線は波長４０５ｎｍの光線に対する球面収差量をそれぞれ表す。 (Example 5)
Table 5 shows lens data of Example 5. The design center wavelength of Example 5 is 546.1 nm. FIG. 22 is a cross-sectional view of the single-eye imaging optical system of Example 5. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, and IL2 is a second monocular lens group. The peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIG. 23 is an aberration diagram of Example 5 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). Here, in the spherical aberration diagram, the solid line represents the ray of wavelength 656 nm, the dotted line represents the ray of wavelength 546 nm, and the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
（実施例６）
　実施例６のレンズデータを表６に示す。実施例６の設計中心波長は、５４６．１ｎｍである。図２４は、実施例６の個眼撮像光学系の断面図である。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ群である。第２個眼レンズ群ＩＬ２の最も像側の面の周辺部は、像側に凸の面形状を有する。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図２５は実施例６の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。ここで、球面収差図において、実線は波長６５６ｎｍの光線、点線は波長５４６ｎｍの光線、一点鎖線は波長４０５ｎｍの光線に対する球面収差量をそれぞれ表す。 (Example 6)
Table 6 shows lens data of Example 6. The design center wavelength of Example 6 is 546.1 nm. FIG. 24 is a cross-sectional view of the single-eye imaging optical system of Example 6. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, and IL2 is a second monocular lens group. The peripheral portion of the surface closest to the image side of the second unit lens group IL2 has a convex surface shape on the image side. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIG. 25 is an aberration diagram of Example 6 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). Here, in the spherical aberration diagram, the solid line represents the ray of wavelength 656 nm, the dotted line represents the ray of wavelength 546 nm, and the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
（実施例７）
　実施例７のレンズデータを表７に示す。実施例７の設計中心波長は、５４６．１ｎｍである。図２６は、実施例７の個眼撮像光学系の断面図である。図中、ＩＬ１は物体側に凸面を形成し正の屈折力を有する第１個眼レンズ、ＩＬ２は第２個眼レンズ群である。Iは撮像面を示し、Ｆは光学的ローパスフィルタやＩＲカットフィルタ、固体撮像素子のシールガラス等を想定した平行平板を示す。図２７は実施例７の収差図（球面収差（ａ）、非点収差・像面湾曲（ｂ）、歪曲収差（ｃ））である。ここで、球面収差図において、実線は波長６５６ｎｍの光線、点線は波長５４６ｎｍの光線、一点鎖線は波長４０５ｎｍの光線に対する球面収差量をそれぞれ表す。 (Example 7)
Table 7 shows lens data of Example 7. The design center wavelength of Example 7 is 546.1 nm. FIG. 26 is a cross-sectional view of the single-eye imaging optical system of Example 7. In the figure, IL1 is a first monocular lens having a convex surface on the object side and having positive refractive power, and IL2 is a second monocular lens group. I denotes an imaging surface, and F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. FIG. 27 is an aberration diagram of Example 7 (spherical aberration (a), astigmatism / field curvature (b), distortion (c)). Here, in the spherical aberration diagram, the solid line represents the ray of wavelength 656 nm, the dotted line represents the ray of wavelength 546 nm, and the alternate long and short dash line represents the amount of spherical aberration with respect to the ray of wavelength 405 nm.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　各条件式に対応する各実施例の値を表８に示す。 Table 8 shows the values of each example corresponding to each conditional expression.
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
　本発明は、本明細書に記載の実施形態、実施例に限定されるものではなく、他の実施形態・実施例・変形例を含むことは、本明細書に記載された実施形態や実施例や技術思想から本分野の当業者にとって明らかである。 The present invention is not limited to the embodiments and examples described in this specification, and includes other embodiments, examples, and modifications. And technical ideas will be apparent to those skilled in the art.
１　　　　　　　画像処理部
２　　　　　　　演算部
３　　　　　　　メモリー
Ｆ　　　　　　　カバーガラス
ＬＡ１　　　　　第１レンズアレイ
ＬＡ２　　　　　第２レンズアレイ
ＬＡ３　　　　　第３レンズアレイ
ＬＨ　　　　　　複眼撮像光学系
ＬＵ　　　　　　撮像ユニット
ＳＲ　　　　　　撮像素子
ＳＳ　　　　　　撮像面 DESCRIPTION OF SYMBOLS 1 Image processing part 2 Computation part 3 Memory F Cover glass LA1 1st lens array LA2 2nd lens array LA3 3rd lens array LH Compound-eye imaging optical system LU Imaging unit SR Imaging element SS Imaging surface

Claims (9)

  1. 　撮像素子の撮像面に複数の物体像を形成する複眼撮像光学系において、
    　前記複眼撮像光学系は、物体側から順に、第１レンズアレイと、少なくとも1枚のレンズアレイを有する第２レンズアレイ群からなり、各レンズアレイは複数の個眼レンズを一体に形成してなり、前記第１レンズアレイと前記第２レンズアレイ群の個眼レンズを光軸方向に積層することで複数の個眼撮像光学系が形成され、該複数の個眼撮像光学系により複数の物体像がそれぞれ形成され、前記個眼撮像光学系の数は前記撮像素子に取得される前記物体像の数と等しくなっており、
    　下記の条件式を満足することを特徴とする複眼撮像光学系。
    　－０．６＜ｆ／ｆ２＜１．５　　　（１）
    但し、
    　ｆ：前記個眼撮像光学系の全系焦点距離(ｍｍ)
    　ｆ２：第２個眼レンズ群の焦点距離（前記第２レンズアレイ群が１枚のレンズアレイからなる場合には、そのレンズアレイの個眼レンズの焦点距離であり、前記第２レンズアレイ群が２枚以上のレンズアレイからなる場合には、各レンズアレイにおける光軸方向に積層された２枚以上の個眼レンズの合成焦点距離をいう）(ｍｍ)
    　尚、焦点距離は、各個眼撮像光学系の設計中心波長で計算されるものとする。     In the compound-eye imaging optical system that forms a plurality of object images on the imaging surface of the imaging device,
    The compound-eye imaging optical system includes, in order from the object side, a first lens array and a second lens array group having at least one lens array, and each lens array is formed by integrally forming a plurality of individual lenses. A plurality of single-lens imaging optical systems are formed by laminating the single-lens lenses of the first lens array and the second lens array group in the optical axis direction, and a plurality of object images are formed by the plurality of single-eye imaging optical systems. Are formed, and the number of the single-eye imaging optical systems is equal to the number of the object images acquired by the imaging device,
    A compound eye imaging optical system satisfying the following conditional expression:
    -0.6 <f / f2 <1.5 (1)
    However,
    f: Total focal length (mm) of the single-eye imaging optical system
    f2: Focal length of the second lens group (if the second lens array group consists of a single lens array, this is the focal length of the single lens of the lens array, and the second lens array group In the case of two or more lens arrays, it means the combined focal length of two or more single-lens lenses stacked in the optical axis direction in each lens array) (mm)
    The focal length is calculated at the design center wavelength of each single-eye imaging optical system.
  2. 　前記第１レンズアレイの個眼レンズである第１個眼レンズは、正の屈折力を有することを特徴とする請求項１に記載の複眼撮像光学系。 2. The compound-eye imaging optical system according to claim 1, wherein the first single-lens that is the single-lens of the first lens array has a positive refractive power.
  3. 　前記第１個眼レンズは、下記の条件式を満足することを特徴とする請求項２に記載の複眼撮像光学系。
    　０．７＜ｆ１／ｆ＜１．５　　　（２）
    但し、
    ｆ１：第１個眼レンズの焦点距離(ｍｍ)     The compound eye imaging optical system according to claim 2, wherein the first single-lens lens satisfies the following conditional expression.
    0.7 <f1 / f <1.5 (2)
    However,
    f1: Focal length of the first single-lens lens (mm)
  4. 　前記第１レンズアレイの個眼レンズである第１個眼レンズの物体側面は、物体側に凸面を有することを特徴とする請求項１～３のいずれかに記載の複眼撮像光学系。 The compound-eye imaging optical system according to any one of claims 1 to 3, wherein an object side surface of a first single-lens lens that is a single-lens lens of the first lens array has a convex surface on the object side.
  5. 　前記第１個眼レンズは、下記の条件式を満足することを特徴とする請求項４に記載の複眼撮像光学系。
    　－５．０＜ｇ１＜－０．５　　　（３）
    但し、
    ｇ１：前記第１個眼レンズのシェーピングファクター
    　　（ｇ１＝（Ｒ１＋Ｒ２）／（Ｒ１－Ｒ２））
    Ｒ１：前記第１個眼レンズの物体側面の曲率半径(ｍｍ)
    Ｒ２：前記第１個眼レンズの像側面の曲率半径(ｍｍ)     The compound eye imaging optical system according to claim 4, wherein the first single-lens lens satisfies the following conditional expression.
    -5.0 <g1 <-0.5 (3)
    However,
    g1: Shaping factor of the first single-lens lens (g1 = (R1 + R2) / (R1-R2))
    R1: Curvature radius of object side surface of the first single-lens lens (mm)
    R2: radius of curvature of the image side surface of the first single-lens lens (mm)
  6. 　前記第２個眼レンズ群における像側に最も近い面の周辺部は、像側に凸の面形状を有することを特徴とする請求項１～５のいずれかに記載の複眼撮像光学系。 6. The compound-eye imaging optical system according to claim 1, wherein a peripheral portion of a surface closest to the image side in the second single-eye lens group has a convex surface shape on the image side.
  7. 　下記の条件式を満足することを特徴とする請求項１～６のいずれかに記載の複眼撮像光学系。
    　０．０５＜ｄ２／ｆ＜０．２５　　　（４）
    但し、
    ｄ２：前記第１レンズアレイの個眼レンズである第１個眼レンズの像側面と、前記第２個眼レンズ群の最も物体側の面との間隔(ｍｍ)     7. The compound-eye imaging optical system according to claim 1, wherein the following conditional expression is satisfied.
    0.05 <d2 / f <0.25 (4)
    However,
    d2: the distance (mm) between the image side surface of the first single-lens lens, which is the single-lens lens of the first lens array, and the most object-side surface of the second single-lens group
  8. 　下記の条件式を満足することを特徴とする請求項１～７のいずれかに記載の複眼撮像光学系。
    　０≦Δ（ｆ／ｆ２）ｍａｘ＜０．６　　　（５）
    但し、
    Δ（ｆ／ｆ２）ｍａｘ：各個眼撮像光学系における（ｆ／ｆ２）の差の最大値の絶対値     The compound-eye imaging optical system according to any one of claims 1 to 7, wherein the following conditional expression is satisfied.
    0 ≦ Δ (f / f2) max <0.6 (5)
    However,
    Δ (f / f2) max: absolute value of the maximum value of the difference of (f / f2) in each single-eye imaging optical system
  9. 　請求項１～８のいずれかに記載の複眼撮像光学系を有することを特徴とする複眼撮像装置。 A compound eye imaging device comprising the compound eye imaging optical system according to any one of claims 1 to 8.
PCT/JP2014/063541 2013-06-17 2014-05-22 Compound-eye imaging optical system and compound-eye imaging device WO2014203675A1 (en)

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