Imaging optical system and imaging apparatus

Abstract

An imaging optical system according to the present disclosure includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a final lens group disposed closest to an image plane side and having a positive refractive power. When focusing, the first lens group and the final lens group are fixed, and the second lens group moves in the optical axis direction. The first lens group includes a first negative lens, a first cemented lens obtained by cementing the negative lens and the positive lens together, and a first air lens sandwiched between the first negative lens and the first cemented lens and having a negative refractive power. The final lens group has a second cemented lens obtained by cementing together a positive lens and a negative lens, a second negative lens, and a second air lens sandwiched between the second cemented lens and the second negative lens and having a negative refractive power.

Description

Technical Field

[0001] The present disclosure relates to an imaging optical system and an imaging device. Background Art

[0002] Imaging optical systems used in imaging devices such as interchangeable-lens digital cameras are required to have a large aperture ratio, minimal aberration variation when focusing from infinity to close distances, and high optical performance throughout the entire focusing range. PTL 1 discloses a wide-angle, single-focus optical system with a strong negative air lens on the object side. PTL 2 discloses a wide-angle, single-focus optical system with negative air lenses on both the object and image sides.

[0003] Citation List

[0004] Patent Literature

[0005] PTL1: Japanese Unexamined Patent Application Publication No. 2017-161848

[0006] PTL2: Japanese Unexamined Patent Application Publication No. 2017-156429 Summary of the Invention

[0007] To achieve a high aperture ratio and high optical performance when focusing from infinity to close distances, and to keep the focus movable section lightweight, it is important to appropriately set the lens composition and the refractive power configuration of each lens.

[0008] It is desirable to provide an imaging optical system and an imaging device including the same, which have small aberration variation associated with focusing and high optical performance throughout the entire focusing area and are easy to make light-weight of a focus movable portion.

[0009] According to an embodiment of the present disclosure, the imaging optical system includes, from the object side to the image plane side, a first lens group having positive refractive power; a second lens group having negative refractive power; and a final lens group having positive refractive power and arranged on the side closest to the image plane. When focusing, the first lens group and the final lens group are both fixed, while the second lens group moves in the optical axis direction. The first lens group includes a first negative lens, a first cemented lens in which a negative lens and a positive lens are cemented together, and a first air lens with negative refractive power sandwiched between the first negative lens and the first cemented lens. The final lens group includes a second cemented lens in which a positive lens and a negative lens are cemented together, a second negative lens, and a second air lens with negative refractive power sandwiched between the second cemented lens and the second negative lens.

[0010] An imaging device according to an embodiment of the present disclosure includes an imaging optical system and an imaging element that outputs an imaging signal corresponding to an optical image formed by the imaging optical system. The imaging optical system is composed of the imaging optical system according to an embodiment of the present disclosure.

[0011] In the imaging optical system or imaging device according to an embodiment of the present disclosure, the composition of each lens group is optimized to have smaller aberration variation associated with focusing and high optical performance in the entire focusing area, and it is easy to make the focus movable part light in weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a lens cross-sectional view of a first configuration example (Example 1) of an imaging optical system according to an embodiment of the present disclosure.

[0013] Figure 2 is an aberration diagram illustrating longitudinal aberration of the imaging optical system according to Example 1 when focusing at infinity.

[0014] Figure 3 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 1 when focusing at a close distance.

[0015] Figure 4 is an aberration diagram illustrating lateral aberration of the imaging optical system according to Example 1 when focusing at infinity.

[0016] Figure 5 It is an aberration diagram illustrating lateral aberration of the imaging optical system according to Example 1 when focusing at a close distance.

[0017] Figure 6 2 is a cross-sectional view of a lens according to a second structural example (Example 2) of the imaging optical system of the embodiment.

[0018] Figure 7 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 2 when focusing at infinity.

[0019] Figure 8 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 2 when focusing at a close distance.

[0020] Figure 9 It is an aberration diagram illustrating lateral aberration of the imaging optical system according to Example 2 when focusing at infinity.

[0021] Figure 10 It is an aberration diagram illustrating lateral aberration of the imaging optical system according to Example 2 when focusing at a close distance.

[0022] Figure 11 3 is a cross-sectional view of a lens according to a third structural example (Example 3) of the imaging optical system of the embodiment.

[0023] Figure 12 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 3 when focusing at infinity.

[0024] Figure 13 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 3 when focusing at a close distance.

[0025] Figure 14 It is an aberration diagram illustrating lateral aberration of the imaging optical system according to Example 3 when focusing at infinity.

[0026] Figure 15 It is an aberration diagram illustrating lateral aberration of the imaging optical system according to Example 3 when focusing at a close distance.

[0027] Figure 16 4 is a cross-sectional view of a lens according to a fourth structural example (Example 4) of the imaging optical system of the embodiment.

[0028] Figure 17 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 4 when focusing at infinity.

[0029] Figure 18 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 4 when focusing at a close distance.

[0030] Figure 19 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 4 when focusing at infinity.

[0031] Figure 20 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 4 when focusing at a close distance.

[0032] Figure 21 4 is a cross-sectional view of a lens of a fifth structural example (Example 5) of the imaging optical system according to the embodiment.

[0033] Figure 22 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 5 when focusing at infinity.

[0034] Figure 23 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 5 when focusing at a close distance.

[0035] Figure 24 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 5 when focusing at infinity.

[0036] Figure 25It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 5 when focusing at a close distance.

[0037] Figure 26 1 is a cross-sectional view of a lens according to a sixth structural example (Example 6) of the imaging optical system of the embodiment.

[0038] Figure 27 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 6 when focusing at infinity.

[0039] Figure 28 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 6 when focusing at a close distance.

[0040] Figure 29 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 6 when focusing at infinity.

[0041] Figure 30 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 6 when focusing at a close distance.

[0042] Figure 31 1 is a cross-sectional view of a lens of a seventh structural example (Example 7) of the imaging optical system according to the embodiment.

[0043] Figure 32 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 7 when focusing at infinity.

[0044] Figure 33 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 7 when focusing at a close distance.

[0045] Figure 34 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 7 when focusing at infinity.

[0046] Figure 35 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 7 when focusing at a close distance.

[0047] Figure 36 1 is a cross-sectional view of a lens according to an eighth structural example (Example 8) of the imaging optical system of the embodiment.

[0048] Figure 37 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 8 when focusing at infinity.

[0049] Figure 38 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 8 when focusing at a close distance.

[0050] Figure 39It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 8 when focusing at infinity.

[0051] Figure 40 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 8 when focusing at a close distance.

[0052] Figure 41 1 is a cross-sectional view of a lens according to a ninth structural example (Example 9) of the imaging optical system of the embodiment.

[0053] Figure 42 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 9 when focusing at infinity.

[0054] Figure 43 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 9 when focusing at a close distance.

[0055] Figure 44 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 9 when focusing at infinity.

[0056] Figure 45 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 9 when focusing at a close distance.

[0057] Figure 46 10. This is a cross-sectional view of a lens according to a tenth structural example (Example 10) of the imaging optical system of the embodiment.

[0058] Figure 47 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 10 when focusing at infinity.

[0059] Figure 48 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 10 when focusing at a close distance.

[0060] Figure 49 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 10 when focusing at infinity.

[0061] Figure 50 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 10 when focusing at a close distance.

[0062] Figure 51 11 is a cross-sectional view of a lens according to an eleventh structural example (Example 11) of the imaging optical system of the embodiment.

[0063] Figure 52 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 11 when focusing at infinity.

[0064] Figure 53 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 11 when focusing at a close distance.

[0065] Figure 54 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 11 when focusing at infinity.

[0066] Figure 55 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 11 when focusing at a close distance.

[0067] Figure 56 12 is a cross-sectional view of a lens according to a twelfth structural example (Example 12) of the imaging optical system of the embodiment.

[0068] Figure 57 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 12 when focusing at infinity.

[0069] Figure 58 It is an aberration diagram illustrating the longitudinal aberration of the imaging optical system according to Example 12 when focusing at a close distance.

[0070] Figure 59 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 12 when focusing at infinity.

[0071] Figure 60 It is an aberration diagram illustrating the lateral aberration of the imaging optical system according to Example 12 when focusing at a close distance.

[0072] Figure 61 is a block diagram illustrating a configuration example of an imaging device.

[0073] Figure 62 This is a block diagram illustrating an example of a schematic configuration of a vehicle control system.

[0074] Figure 63 1 and 2 are diagrams for assisting in explaining examples of installation positions of the vehicle exterior information detection section and the imaging section.

[0075] Figure 64 It is a diagram illustrating an example of a schematic configuration of an endoscope system.

[0076] Figure 65 It is a graphic description Figure 64 A block diagram of an example of a functional configuration of a camera and a camera control unit (CCU) shown in FIG.

[0077] Figure 66 is a diagram illustrating an example of a schematic configuration of a microsurgery system. DETAILED DESCRIPTION

[0078] Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. It should be noted that the description is given in the following order.

[0079] 0. Comparative Example

[0080] 1. Basic composition of the optical system

[0081] 2. Function and effect

[0082] 3. Application examples in imaging devices

[0083] 4. Numerical Examples of Optical Systems

[0084] 5. Practical Application Examples

[0085] 6. Other embodiments

[0086] <0. Comparative Example>

[0087] The wide-angle single-focus optical system disclosed in PTL 1 (Japanese Unexamined Patent Application Publication No. 2017-161848) has a strongly negative air lens on the object side, while the air lens on the image side has weak refractive power and moves during focusing, thus failing to perform sufficient aberration correction. The wide-angle single-focus optical system disclosed in PTL 2 (Japanese Unexamined Patent Application Publication No. 2017-156429) has a strongly negative air lens on the object side, while the air lens on the image side has weak refractive power and includes a non-cemented lens element adjacent to the air lens on the image side, thus failing to perform sufficient aberration correction.

[0088] Double-Gauss or Biogon imaging optical systems are characterized by their ability to minimize aberration variation relative to image height by employing a symmetrical refractive power configuration. However, this type of imaging optical system significantly increases the weight of the focus-moving unit when attempting to focus from infinity to close distances, inhibiting high-speed autofocusing using an actuator. Therefore, in order to achieve a high aperture ratio and high optical performance when focusing from infinity to close distances, while also minimizing the weight of the focus-moving unit, it is important to appropriately design the lens configuration and the refractive power configuration of each lens.

[0089] Therefore, it is desirable to provide an imaging optical system and an imaging device including such an imaging optical system, which have smaller aberration variation associated with focusing from infinity to a close distance, and high optical performance throughout the entire focusing area, and are easy to make the focus movable portion light in weight.

[0090] <1. Basic Structure of the Optical System>

[0091] Figure 1The diagram illustrates a first configuration example of the imaging optical system according to an embodiment of the present disclosure, and corresponds to the configuration of Example 1 described later. Figure 6 The diagram illustrates a second configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 2 described later. Figure 11 The diagram illustrates a third configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 3 described later. Figure 16 The diagram illustrates a fourth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 4 described later. Figure 21 The diagram illustrates a fifth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 5 described later. Figure 26 The diagram illustrates a sixth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 6 described later. Figure 31 The diagram illustrates a seventh configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 7 described later. Figure 36 The diagram illustrates an eighth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 8 described later. Figure 41 The diagram illustrates a ninth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 9 described later. Figure 46 The diagram illustrates a tenth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 10 described later. Figure 51 The diagram illustrates an eleventh configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 11 described later. Figure 56 The diagram illustrates a twelfth configuration example of the imaging optical system according to the embodiment, and corresponds to the configuration of Example 12 described later.

[0092] The imaging optical system according to the embodiment is applicable to an imaging apparatus such as a single-lens camera, a digital camera, a film camera, a video camera, a broadcast camera, or a surveillance camera, for example.

[0093] exist Figure 1and other drawings, Z1 represents the optical axis. An optical component GC for protecting the imaging element, such as a cover glass, may be arranged between the image plane and any one of the imaging optical systems 1 to 12 according to the first to twelfth configuration examples. In addition, in addition to the cover glass, various filters such as a low-pass filter or an infrared cutoff filter may be arranged as the optical component GC. In the case where the imaging optical system according to the embodiment is applied to a digital camera, a video camera, or the like, the image plane of the imaging optical system corresponds to the imaging surface of an imaging element such as a CCD (charge coupled device) sensor or a CMOS (complementary metal oxide semiconductor) sensor. In the case where the imaging optical system according to the embodiment is applied to a film camera, the image plane of the imaging optical system corresponds to the film surface.

[0094] It should be noted that Figure 1 and other figures illustrate the configuration of the lens when focusing at infinity. Figure 1 In the drawings and other figures, the left side indicates the object side, and the right side indicates the image side.

[0095] In the following, appropriately and in accordance with Figure 1 The configuration of the imaging optical system according to the embodiment of the present disclosure is described in association with the imaging optical systems 1 to 12 of the respective configuration examples illustrated in other drawings. However, the technology according to the present disclosure is not limited to the configuration examples illustrated in the drawings.

[0096] The imaging optical system according to the embodiment includes, in order from the object side to the image plane side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a final lens group having positive refractive power and arranged closest to the image plane. It should be noted that any of the imaging optical systems 1 to 12 according to Examples 1 to 12 described later includes the third lens group G3 as the final lens group.

[0097] In the imaging optical system according to the embodiment, the first lens group G1 and the final lens group are fixed, and the second lens group G2 moves parallel to the optical axis direction during focusing.

[0098] The first lens group G1 includes a first negative lens Gnf, a first cemented lens in which a negative lens and a positive lens are cemented, and a first air lens Gaf having a negative refractive power sandwiched between the first negative lens Gnf and the first cemented lens. It should be noted that in the imaging optical system 1 ( Figure 1 ), for example, lens L14 corresponds to the first negative lens Gnf, and lenses L15 and L16 correspond to the first cemented lens.

[0099] The final lens group includes a second cemented lens in which a positive lens and a negative lens are cemented, a second negative lens Gnr, and a second air lens Gar having a negative refractive power sandwiched between the second cemented lens and the second negative lens Gnr. It should be noted that in the imaging optical system 1 ( Figure 1 ), for example, lenses L32 and L33 correspond to a second cemented lens, and lens L34 corresponds to a second negative lens Gnr.

[0100] In addition to this, the imaging optical system according to the embodiment may also satisfy predetermined conditional expressions and the like described later.

[0101] <2. Functions and Effects>

[0102] Next, the effects and functions of the imaging optical system according to the embodiment of the present disclosure will be described. In addition, a more preferable configuration of the imaging optical system according to the embodiment of the present disclosure and its effects and functions will be described.

[0103] It should be noted that the effects described in this article are merely exemplary and are not limited thereto, and other effects may also be included.

[0104] According to the imaging optical system of the embodiment, the configuration of each lens group is optimized to achieve minimal aberration variation associated with focusing from infinity to close distances, high optical performance throughout the entire focusing range, and facilitate lightweighting of the movable focus portion. This makes it possible to provide an imaging optical system and an imaging device including such an imaging optical system, each of which has minimal aberration variation associated with focusing, high optical performance throughout the entire focusing range, and facilitates lightweighting of the movable focus portion.

[0105] The imaging optical system according to the embodiment may satisfy the following conditional expression (1):

[0106] 0.5<|faf| / f<2.0......(1)

[0107] in

[0108] faf represents the focal length of the first air lens Gaf, and

[0109] f represents the focal length of the entire system.

[0110] Conditional expression (1) is a conditional expression for appropriately setting the refractive power of the first air lens Gaf having a negative refractive power included in the first lens group G1. Satisfying conditional expression (1) makes it easier to correct aberrations while allowing the first lens group G1 to have a small diameter. Exceeding the upper limit value of conditional expression (1) causes the refractive power of the first air lens Gaf having a negative refractive power to be too weak, thereby making it difficult to achieve a reduction in the diameter of the first lens group G1. On the other hand, falling below the lower limit value of conditional expression (1) causes the refractive power of the first air lens Gaf having a negative refractive power to be too strong, thereby making it difficult to favorably correct coma aberration occurring in the first lens group G1.

[0111] It should be noted that setting the numerical range of the conditional expression (1) as in the following conditional expressions (1a), (1b), and (1c) makes it possible to obtain higher effects.

[0112] 0.65<|faf| / f<1.9......(1a)

[0113] 0.75<|faf| / f<1.7......(1b)

[0114] 1.0<|faf| / f<1.6......(1c)

[0115] In addition, the imaging optical system according to the embodiment can satisfy the following conditional expression (2):

[0116] 0.5<|far| / f<4.5......(2)

[0117] in

[0118] far represents the focal length of the second air lens Gar, and

[0119] f represents the focal length of the entire system.

[0120] Conditional expression (2) is a conditional expression for appropriately setting the refractive power of the second air lens Gar having a negative refractive power included in the final lens group. Satisfying conditional expression (2) makes it easier to correct aberrations while allowing the final lens group to have a small diameter. Exceeding the upper limit value of conditional expression (2) causes the refractive power of the second air lens Gar having a negative refractive power to be too weak, thereby making it difficult to achieve a reduction in the diameter of the final lens group. On the other hand, falling below the lower limit value of conditional expression (2) causes the refractive power of the second air lens Gar having a negative refractive power to be too strong, thereby making it difficult to favorably correct coma aberration occurring in the final lens group.

[0121] It should be noted that setting the numerical range of conditional expression (2) as in the following conditional expressions (2a), (2b), and (2c) enables obtaining higher effects.

[0122] 0.6<|far| / f<4.0......(2a)

[0123] 0.8<|far| / f<3.0......(2b)

[0124] 1.0<|far| / f<2.5......(2c)

[0125] In addition, the imaging optical system according to the embodiment can satisfy the following conditional expression (3):

[0126] 0.1 <faf / far<2.1......(3)

[0127] in

[0128] faf represents the focal length of the first air lens Gaf, and

[0129] far represents the focal length of the second air lens Gar.

[0130] Conditional expression (3) is a conditional expression for appropriately setting the refractive power of the first air lens Gaf having a negative refractive power included in the first lens group G1 and the refractive power of the second air lens Gar having a negative refractive power included in the final lens group. Satisfying conditional expression (3) allows the first air lens Gaf and the second air lens Gar to be in a symmetrical refractive power configuration with the aperture stop St inserted therebetween, thereby making it easier to correct aberrations while allowing the entire system to be small and light. Exceeding the upper limit value of conditional expression (3) makes it difficult to reduce the diameter of the final lens group and makes it difficult to favorably correct coma aberrations that occur in the entire system. On the other hand, being below the lower limit value of conditional expression (3) makes it difficult to reduce the diameter of the first lens group G1 and makes it difficult to favorably correct coma aberrations that occur in the entire system.

[0131] It should be noted that setting the numerical range of the conditional expression (3) as in the following conditional expression (3a), (3b), or (3c) enables obtaining higher effects.

[0132] 0.1 <faf / far<2.1......(3a)

[0133] 0.35 <faf / far<1.5......(3b)

[0134] 0.45 <faf / far<1.0......(3c)

[0135] In addition, in the imaging optical system according to the embodiment, the first lens group G1 may include at least one cemented lens, and may be composed of a first split lens group G1a and a second split lens G1b, wherein the cemented lens on the side closest to the image plane among the at least one cemented lens is set as a boundary. The first split lens group G1a includes the at least one cemented lens. The second split lens group G1b is arranged on a side closer to the image plane than the cemented lens on the side closest to the image plane among the at least one cemented lens. In this case, the following conditional expression (4) can be satisfied:

[0136] 0.1<|f1b / f2|<2.0......(4)

[0137] in

[0138] f1b represents the focal length of the second split lens group G1b, and

[0139] f2 represents the focal length of the second lens group G2.

[0140] Conditional expression (4) is a conditional expression for appropriately setting the focal length f1b of the second split lens group G1b and the focal length f2 of the second lens group G2. Satisfying conditional expression (4) makes it easier to correct aberrations while allowing the entire system to be small and light. Exceeding the upper limit value of conditional expression (4) results in insufficient refractive power of the second split lens group G1b, making it difficult to achieve a reduction in the diameter of the entire system. On the other hand, falling below the lower limit value of conditional expression (4) results in insufficient refractive power of the second lens group G2, making it difficult to reduce the total length of the entire system.

[0141] It should be noted that setting the numerical range of conditional expression (4) as in the following conditional expression (4a), (4b), or (4c) enables obtaining higher effects.

[0142] 0.2<|f1b / f2|<1.5......(4a)

[0143] 0.3<|f1b / f2|<0.55......(4b)

[0144] 0.4<|f1b / f2|<0.5......(4c)

[0145] In addition, the imaging optical system according to the embodiment can satisfy the following conditional expression (5):

[0146] 0.1<|f1 / f2|<1.5......(5)

[0147] in

[0148] f1 represents the focal length of the first lens group G1, and

[0149] f2 represents the focal length of the second lens group G2.

[0150] Conditional expression (5) is a conditional expression for appropriately setting the focal length f1 of the first lens group G1 and the focal length f2 of the second lens group G2. Satisfying conditional expression (5) makes it easier to suppress aberration changes during focusing while allowing the entire system to be small and light. Exceeding the upper limit value of conditional expression (5) causes the refractive power of the second lens group G2 to be too strong, making it difficult to suppress changes in spherical aberration during focusing. On the other hand, falling below the lower limit value of conditional expression (5) causes the refractive power of the second lens group G2 to be insufficient, making it difficult to reduce the total length of the entire system.

[0151] It should be noted that setting the numerical range of conditional expression (5) as in the following conditional expression (5a), (5b), or (5c) enables obtaining higher effects.

[0152] 0.1<|f1 / f2|<1.3......(5a)

[0153] 0.2<|f1 / f2|<1.1......(5b)

[0154] 0.5<|f1 / f2|<1.0......(5c)

[0155] In addition, in the imaging optical system according to the embodiment, the first negative lens Gnf may have an aspherical surface. The first negative lens Gnf including the aspherical surface facilitates correction of various aberrations, particularly high-order coma aberrations.

[0156] In addition, in the imaging optical system according to the embodiment, the second negative lens Gnr may have an aspherical surface. The second negative lens Gnr including the aspherical surface facilitates correction of various aberrations, particularly high-order coma aberrations.

[0157] In addition, in the imaging optical system according to the embodiment, the first lens group G1 may include, in order from the object side to the image plane side, a first negative lens Gnf, a first cemented lens, and at least one first positive lens. This makes it easier to properly correct spherical aberration and coma in the first lens group G1. It should be noted that in the imaging optical system 1 ( Figure 1 ), lens L14 corresponds to the first negative lens Gnf, lenses L15 and L16 correspond to the first cemented lens, and lenses L17 and L18 correspond to the first positive lens.

[0158] In addition, in the imaging optical system according to the embodiment, the final lens group may include a second positive lens, a second cemented lens, and a second negative lens Gnr in order from the object side to the image plane side. This makes it easier to properly correct spherical aberration and coma in the final lens group. It should be noted that in the imaging optical system 1 ( Figure 1 ), lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr.

[0159] In addition, in the imaging optical system according to the embodiment, the second lens group G2 can be composed of a third negative lens and a third positive lens in order from the object side to the image plane side. This makes it easier to correct aberrations during focusing while achieving a reduction in weight of the second lens group G2. It should be noted that in the imaging optical system 1 ( Figure 1 ), lens L21 corresponds to a third negative lens, and lens L22 corresponds to a third positive lens.

[0160] Furthermore, the imaging optical system according to the embodiment can be composed, in order from the object side to the image plane side, of the first lens group G1, the second lens group G2, and the third lens group G3, which serves as the final lens group having positive refractive power. A configuration can be employed in which, during focusing, the first lens group G1 and the third lens group G3 are both fixed, while the second lens group G2 moves along the optical axis. This simplifies the group configuration, making it easier to reduce the total optical length.

[0161] In the imaging optical system according to the embodiment, the first cemented lens in the first lens group G1 may be composed of a cemented lens in which a negative lens and a positive lens are cemented together in this order from the object side to the image plane side. Furthermore, the second cemented lens in the final lens group may be composed of a cemented lens in which a positive lens and a negative lens are cemented together in this order from the object side to the image plane side.

[0162] In the imaging optical system according to the embodiment, the first cemented lens in the first lens group G1 may be composed of a cemented lens in which a negative lens having a concave surface on the object side and a positive lens having a convex surface on the image side are cemented in this order from the object side to the image plane side. Furthermore, the second cemented lens in the final lens group may be composed of a cemented lens in which a positive lens having a convex surface on the object side and a negative lens having a concave surface on the image plane side are cemented in this order from the object side to the image plane side.

[0163] In the imaging optical system according to the embodiment, it is effective in terms of optical performance to have a symmetrical structure for the first lens group G1 and the final lens group. Therefore, in the first lens group G1 and the final lens group, a first air lens Gaf having negative refractive power and a second air lens Gar having negative refractive power can be symmetrically arranged, with an aperture stop St interposed therebetween. In this case, the lens structure forming the first air lens Gaf (a first negative lens Gnf and a first cemented lens) and the lens structure forming the second air lens Gar (a second cemented lens and a second negative lens) can be symmetrical structures with an aperture stop St interposed therebetween. Therefore, the first air lens Gaf can be formed, from the object side to the image side, in sequence from the first negative lens Gnf and a first cemented lens in which a negative lens and a positive lens are cemented together. Furthermore, the second air lens Gar can be formed, from the object side to the image side, in sequence from the second negative lens Gnf and a second cemented lens in which a positive lens and a negative lens are cemented together, and a second negative lens Gnr. Alternatively, the first cemented lens can be composed of a negative lens having a concave surface on the object side and a positive lens having a convex surface on the image side, cemented in order from the object side to the image plane side. Alternatively, the second cemented lens can be composed of a positive lens having a convex surface on the object side and a negative lens having a concave surface on the image plane side, cemented in order from the object side to the image plane side. This allows the lens configurations forming the first air lens Gaf and the lens configuration forming the second air lens Gar to be symmetrical, with the aperture stop St interposed between them, thereby achieving excellent coma correction.

[0164] <3. Example of Application to Imaging Device>

[0165] Next, an example in which the imaging optical system according to the embodiment of the present disclosure is applied to a specific imaging device is described.

[0166] Figure 61 The diagram illustrates an example of the configuration of an imaging device 100 to which the imaging optical system according to the embodiment is applied. The imaging device 100 is, for example, a digital camera and includes a camera block 110, a camera signal processing section 20, an image processing section 30, an LCD (Liquid Crystal Display) 40, an R / W (Reader / Writer) 50, a CPU (Central Processing Unit) 60, an input section 70, and a lens drive control section 80.

[0167] The camera block 110 has an imaging function and includes an imaging lens 111 and an imaging element 112 such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The imaging element 112 converts the optical image formed by the imaging lens 111 into an electrical signal, thereby outputting an imaging signal (image signal) corresponding to the optical image. As the imaging lens 111, a device according to the method described in the embodiment of the present invention can be applied. Figure 1 and any of the imaging optical systems 1 to 12 of the respective configuration examples illustrated in other drawings.

[0168] The camera signal processing section 20 performs various types of signal processing on the image signal output from the imaging element 112 , including, for example, analog-to-digital conversion, noise removal, image quality correction, or conversion into luminance and color difference signals.

[0169] The image processing section 30 performs recording and reproduction processing of image signals. The image processing section 30 performs processing including, for example, compression encoding and expansion decoding processing of image signals based on a predetermined image data format, and processing for converting data specifications such as resolution.

[0170] The LCD 40 has a function of displaying various types of data, including, for example, the status of user operations on the input section 70 and captured images. The R / W 50 writes image data encoded by the image processing section 30 to the memory card 1000 and reads image data recorded in the memory card 1000. The memory card 1000 is, for example, a semiconductor memory that is attachable to and detachable from a slot coupled to the R / W 50.

[0171] The CPU 60 functions as a control processing unit that controls each circuit block provided in the imaging device 100. The CPU 60 controls each circuit block based on, for example, command input signals from the input unit 70. The input unit 70 includes, for example, various switches on which the user performs desired operations. For example, the input unit 70 includes a shutter release button for performing a shutter operation, a selector switch for selecting an operating mode, and the like. The input unit 70 outputs command input signals corresponding to the user's operations to the CPU 60. The lens drive control unit 80 controls the drive of the lenses arranged in the camera block 110. Based on control signals from the CPU 60, the lens drive control unit 80 controls, for example, the motors (not shown) that drive the various lenses of the imaging lens 111.

[0172] Next, the operation in the imaging apparatus 100 is described.

[0173] In a standby state during image capture, an image signal corresponding to an image captured by the camera block 110 is output to the LCD 40 via the camera signal processing section 20 under the control of the CPU 60, thereby being displayed as a camera preview image. Furthermore, when, for example, a zoom or focus instruction input signal is input from the input section 70, the CPU 60 outputs a control signal to the lens drive control section 80. This causes the predetermined lens of the imaging lens 111 to be moved under the control of the lens drive control section 80.

[0174] When a shutter (not shown) of the camera block 110 is operated in response to an instruction input signal from the input section 70, a captured image signal is output from the camera signal processing section 20 to the image processing section 30, where it undergoes compression encoding processing and is converted into digital data in a predetermined data format. The converted data is output to the R / W 50 so as to be written to the memory card 1000.

[0175] It should be noted that focusing is performed, for example, when the shutter release button of the input section 70 is half-pressed, or when the shutter release button is fully pressed for recording (image capture). Focusing is performed by causing the lens drive control section 80 to move a predetermined lens of the imaging lens 111 based on a control signal from the CPU 60.

[0176] When image data recorded in the memory card 1000 is to be reproduced, the R / W 50 reads the predetermined image data from the memory card 1000 according to an operation performed on the input unit 70. The predetermined image data read from the memory card 1000 is subjected to expansion decoding processing by the image processing unit 30. Thereafter, a reproduced image signal is output to the LCD 40, thereby displaying the reproduced image.

[0177] It should be noted that while the above embodiments illustrate the application of the imaging device to digital still cameras and the like, the scope of application of the imaging device is not limited to digital still cameras. The imaging device can be applied to various other imaging devices. For example, the imaging device is suitable for digital SLR cameras, digital non-reflex cameras, digital video cameras, surveillance cameras, and the like. Furthermore, the imaging device can be widely used in, for example, digital input / output devices, such as camera units of mobile phones equipped with cameras or information terminals equipped with cameras. Furthermore, the imaging device is also suitable for interchangeable-lens cameras.

[0178] [example]

[0179] <4. Numerical Examples of Optical Systems>

[0180] Next, a specific numerical example of the imaging optical system according to an embodiment of the present disclosure will be described. Here, a description will be given of a case where specific numerical values ​​are applied to the imaging optical system. Figure 1 and numerical examples of the imaging optical systems 1 to 12 of the respective configuration examples illustrated in other drawings.

[0181] It should be noted that the meanings of the various symbols indicated in the following tables and descriptions are as follows. "Si" represents the number of the i-th surface marked in increasing order from the side closest to the object. "ri" represents the value of the paraxial curvature radius of the i-th surface (mm). "di" represents the value of the interval on the optical axis between the i-th surface and the (i+1)-th surface (mm). "ndi" represents the value of the refractive index of the material of the optical element having the i-th surface with respect to the d-line (wavelength 587.6nm). "νdi" represents the value of the Abbe number of the material of the optical element having the i-th surface in the d-line. "φi" represents the value of the effective diameter of the i-th surface (mm). The part where the value of "ri" is "∞" indicates a plane, an aperture stop surface, etc. "ASP" in the surface number (Si) column indicates that the surface is composed of an aspherical shape. "STO" in the surface number column indicates that the aperture stop St is arranged at the corresponding position. "OBJ" in the surface number column indicates that the surface is an object plane (subject plane). "IMG" in the surface number column indicates that the surface is the image plane. "f" represents the focal length of the entire system (unit: mm). "Fno" represents the open F value (F-number). "ω" represents the half-field angle (unit: °). "Y" represents the maximum image height (unit: mm), which determines the half-field angle. "L" represents the total optical length (the distance on the optical axis from the surface closest to the object to the image plane IMG) (unit: mm).

[0182] In addition, some lenses used in each example have lens surfaces composed of aspherical surfaces. The aspherical shape is defined by the following expression. It should be noted that in each table showing aspherical coefficients described later, "Ei" represents an exponential notation with 10 as the base, i.e., "10 -i ”; for example, “0.12345E-05” means “0.12345×10 -5 ”.

[0183] (Expression of aspheric surface)

[0184] x=c 2 y 2 / (1+(1-(1+k)c 2 y 2 ) 1 / 2 )+A4·y 4 +A6·y 6 +A8·y 8 +A10·y 10 +A12·y 12 +A14·y 14

[0185] Here, it is assumed that "x" is the distance from the vertex of the lens surface in the direction of the optical axis (sagittal height), "y" is the height in the direction perpendicular to the optical axis, "c" is the paraxial curvature (the inverse of the radius of curvature) at the vertex of the lens surface, and "k" is the conic (quadratic curve) constant. A4, A6, A8, A10, A12, and A14 are the 4th, 6th, 8th, 10th, 12th, and 14th order aspheric coefficients, respectively.

[0186] [Example 1]

[0187] Table 1 shows the Figure 1 Table 2 shows the basic lens data of the imaging optical system 1 of Example 1 illustrated in Table 1. Table 2 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 1 according to Example 1. Table 3 shows the data of the surface spacing that is variable when focusing in the imaging optical system 1 according to Example 1. It should be noted that Table 2 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 3 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close distances. Table 4 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 1 according to Example 1. Table 5 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 1 according to Example 1.

[0188] The imaging optical system 1 according to Example 1 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0189] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0190] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16, an aperture stop St, a lens L17, and a lens L18. In the imaging optical system 1 according to Example 1, lens L14 corresponds to the first negative lens Gnf, lenses L15 and L16 correspond to the first cemented lens, and lenses L17 and L18 correspond to the first positive lens. Furthermore, in the imaging optical system 1 according to Example 1, lenses L11 to L16 correspond to the first split lens group G1a, while lenses L17 and L18 correspond to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0191] The second lens group G2 has negative refractive power. The second lens group G2 includes lenses L21 and L22. In the imaging optical system 1 according to Example 1, lens L21 corresponds to a third negative lens, and lens L22 corresponds to a third positive lens.

[0192] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 1 according to Example 1, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0193] [Table 1]

[0194]

[0195]

[0196] [Table 2]

[0197]

[0198] [Table 3]

[0199]

[0200] [Table 4]

[0201]

[0202]

[0203] [Table 5]

[0204]

[0205] Figure 2 The diagram illustrates the longitudinal aberration of the imaging optical system 1 according to Example 1 when focusing at infinity. Figure 3 The diagram illustrates longitudinal aberration of the imaging optical system 1 according to Example 1 at close focusing. Figure 4 The diagram illustrates the lateral aberration of the imaging optical system 1 according to Example 1 when focusing at infinity. Figure 5 The diagram illustrates lateral aberration of the imaging optical system 1 according to Example 1 at close focusing.

[0206] As longitudinal aberration, Figure 2 and Figure 3 The diagram illustrates spherical aberration, astigmatism (field curvature), and distortion. Figure 2 and Figure 3 Spherical aberration diagram and Figure 4 and Figure 5 In the lateral aberration diagram of , the solid line indicates the value on the d-line (587.56 nm), the dashed line indicates the value on the g-line (435.84 nm), and the dotted line indicates the value on the C-line (656.27 nm). Figure 2 and Figure 3 In the astigmatism diagram, S represents the value on the sagittal image plane, and T represents the value on the tangential image plane. Figure 2 and Figure 3 The astigmatism and distortion diagrams in the figure illustrate the values ​​along the d-line.

[0207] The same applies to the aberration diagrams in other examples that follow.

[0208] As can be appreciated from each aberration diagram, the imaging optical system 1 according to Example 1 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0209] [Example 2]

[0210] Table 6 shows the Figure 6 Table 7 shows the basic lens data of the imaging optical system 2 of Example 2 illustrated in the figure. Table 7 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 2 according to Example 2. Table 8 shows the data of the surface spacing that is variable when focusing in the imaging optical system 2 according to Example 2. It should be noted that Table 7 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 8 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close distances. Table 9 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 2 according to Example 2. Table 10 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 2 according to Example 2.

[0211] The imaging optical system 2 according to Example 2 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0212] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0213] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16, an aperture stop St, a lens L17, and a lens L18. In the imaging optical system 2 according to Example 2, lens L14 corresponds to the first negative lens Gnf, lenses L15 and L16 correspond to the first cemented lens, and lenses L17 and L18 correspond to the first positive lens. Furthermore, in the imaging optical system 2 according to Example 2, lenses L11 to L16 correspond to the first split lens group G1a, while lenses L17 and L18 correspond to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0214] The second lens group G2 has negative refractive power. The second lens group G2 includes lenses L21 and L22. In the imaging optical system 2 according to Example 2, lens L21 corresponds to a third negative lens, and lens L22 corresponds to a third positive lens.

[0215] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 2 according to Example 2, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0216] [Table 6]

[0217]

[0218]

[0219] [Table 7]

[0220]

[0221] [Table 8]

[0222]

[0223] [Table 9]

[0224]

[0225]

[0226] [Table 10]

[0227]

[0228] Figure 7The diagram illustrates the longitudinal aberration of the imaging optical system 2 according to Example 2 when focusing at infinity. Figure 8 The diagram illustrates the longitudinal aberration of the imaging optical system 2 according to Example 2 at close focusing. Figure 9 The diagram illustrates the lateral aberration of the imaging optical system 2 according to Example 2 when focusing at infinity. Figure 10 The diagram illustrates the lateral aberration of the imaging optical system 2 according to Example 2 at close focusing.

[0229] As can be appreciated from each aberration diagram, the imaging optical system 2 according to Example 2 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0230] [Example 3]

[0231] Table 11 shows the Figure 11 Table 12 shows the basic lens data of the imaging optical system 3 of Example 3 illustrated in Table 12. Table 12 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 3 according to Example 3. Table 13 shows the data of the surface spacing that is variable when focusing in the imaging optical system 3 according to Example 3. It should be noted that Table 12 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 13 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 14 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 3 according to Example 3. Table 15 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 3 according to Example 3.

[0232] The imaging optical system 3 according to Example 3 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0233] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0234] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16, an aperture stop St, a lens L17, and a lens L18. In the imaging optical system 3 according to Example 3, lens L14 corresponds to the first negative lens Gnf, lenses L15 and L16 correspond to the first cemented lens, and lenses L17 and L18 correspond to the first positive lens. Furthermore, in the imaging optical system 3 according to Example 3, lenses L11 to L16 correspond to the first split lens group G1a, while lenses L17 and L18 correspond to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0235] The second lens group G2 has negative refractive power. The second lens group G2 includes lenses L21 and L22. In the imaging optical system 3 according to Example 3, lens L21 corresponds to a third negative lens, and lens L22 corresponds to a third positive lens.

[0236] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 3 according to Example 3, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0237] [Table 11]

[0238]

[0239]

[0240] [Table 12]

[0241]

[0242] [Table 13]

[0243]

[0244] [Table 14]

[0245]

[0246]

[0247] [Table 15]

[0248]

[0249]

[0250] Figure 12 The diagram illustrates the longitudinal aberration of the imaging optical system 3 according to Example 3 when focusing at infinity. Figure 13 The diagram illustrates the longitudinal aberration of the imaging optical system 3 according to Example 3 at close focusing. Figure 14 The diagram illustrates the lateral aberration of the imaging optical system 3 according to Example 3 when focusing at infinity. Figure 15 The diagram illustrates the lateral aberration of the imaging optical system 3 according to Example 3 at close focusing.

[0251] As can be appreciated from each aberration diagram, the imaging optical system 3 according to Example 3 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0252] [Example 4]

[0253] Table 16 shows the Figure 16 Table 17 shows the basic lens data of the imaging optical system 4 of Example 4 illustrated in Table 17. Table 17 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 4 according to Example 4. Table 18 shows the data of the surface intervals that are variable when focusing in the imaging optical system 4 according to Example 4. It should be noted that Table 17 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 18 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 19 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 4 according to Example 4. Table 20 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 4 according to Example 4.

[0254] The imaging optical system 4 according to Example 4 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0255] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0256] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L18 and an aperture stop St. In the imaging optical system 4 according to Example 4, lens L14 corresponds to the first negative lens Gnf, lenses L15 and L16 correspond to the first cemented lens, and lenses L17 and L18 correspond to the first positive lens. Furthermore, in the imaging optical system 4 according to Example 4, lenses L11 to L16 correspond to the first split lens group G1a, and lenses L17 and L18 correspond to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0257] The second lens group G2 has negative refractive power. The second lens group G2 includes lenses L21 and L22. In the imaging optical system 4 according to Example 4, lens L21 corresponds to a third negative lens, and lens L22 corresponds to a third positive lens.

[0258] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 4 according to Example 4, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0259] [Table 16]

[0260]

[0261]

[0262] [Table 17]

[0263]

[0264] [Table 18]

[0265]

[0266] [Table 19]

[0267]

[0268] [Table 20]

[0269]

[0270]

[0271] Figure 17 The diagram illustrates the longitudinal aberration of the imaging optical system 4 according to Example 4 when focusing at infinity. Figure 18 The diagram illustrates the longitudinal aberration of the imaging optical system 4 according to Example 4 at close focusing. Figure 19 The diagram illustrates the lateral aberration of the imaging optical system 4 according to Example 4 when focusing at infinity. Figure 20 The diagram illustrates the lateral aberration of the imaging optical system 4 according to Example 4 when focusing at a close distance.

[0272] As can be appreciated from each aberration diagram, the imaging optical system 4 according to Example 4 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0273] [Example 5]

[0274] Table 21 shows the Figure 21 Table 22 shows the basic lens data of the imaging optical system 5 of Example 5 illustrated in the figure. Table 22 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 5 according to Example 5. Table 23 shows the data of the surface spacing that is variable when focusing in the imaging optical system 5 according to Example 5. It should be noted that Table 22 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 23 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 24 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 5 according to Example 5. Table 25 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 5 according to Example 5.

[0275] The imaging optical system 5 according to Example 5 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0276] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0277] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16 and an aperture stop St. In the imaging optical system 5 according to Example 5, lens L12 corresponds to the first negative lens Gnf, lenses L13 and L14 correspond to the first cemented lens, and lenses L15 and L16 correspond to the first positive lens. Furthermore, in the imaging optical system 5 according to Example 5, lenses L11 to L14 correspond to the first split lens group G1a, while lenses L15 and L16 correspond to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0278] The second lens group G2 has negative refractive power. The second lens group G2 includes lenses L21 and L22. In the imaging optical system 5 according to Example 5, lens L21 corresponds to a third negative lens, and lens L22 corresponds to a third positive lens.

[0279] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 5 according to Example 5, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0280] [Table 21]

[0281]

[0282]

[0283] [Table 22]

[0284]

[0285] [Table 23]

[0286]

[0287]

[0288] [Table 24]

[0289]

[0290] [Table 25]

[0291]

[0292] Figure 22 The diagram illustrates longitudinal aberration of the imaging optical system 5 according to Example 5 when focusing at infinity at the wide-angle end. Figure 23 Diagram illustrating longitudinal aberration at close focusing distance. Figure 24 The diagram illustrates the lateral aberration of the imaging optical system 5 according to Example 5 when focusing at infinity. Figure 25 The diagram illustrates the lateral aberration of the imaging optical system 5 according to Example 5 when focusing at a close distance.

[0293] As can be appreciated from each aberration diagram, the imaging optical system 5 according to Example 5 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0294] [Example 6]

[0295] Table 26 shows the Figure 26 Table 27 shows the basic lens data of the imaging optical system 6 of Example 6 illustrated in Table 27. Table 27 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 6 according to Example 6. Table 28 shows the data of the surface spacing that is variable when focusing in the imaging optical system 6 according to Example 6. It should be noted that Table 27 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 28 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 29 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 6 according to Example 6. Table 30 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 6 according to Example 6.

[0296] The imaging optical system 6 according to Example 6 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0297] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0298] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L15 and an aperture stop St. In the imaging optical system 6 according to Example 6, lens L12 corresponds to the first negative lens Gnf, lenses L13 and L14 correspond to the first cemented lens, and lens L15 corresponds to the first positive lens. Furthermore, in the imaging optical system 6 according to Example 6, lenses L11 to L14 correspond to the first split lens group G1a, and lens L15 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0299] The second lens group G2 has negative refractive power and includes a lens L21.

[0300] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 6 according to Example 6, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0301] [Table 26]

[0302]

[0303]

[0304] [Table 27]

[0305]

[0306] [Table 28]

[0307]

[0308] [Table 29]

[0309]

[0310]

[0311] [Table 30]

[0312]

[0313] Figure 27 The diagram illustrates longitudinal aberration of the imaging optical system 6 according to Example 6 when focusing at infinity at the wide-angle end. Figure 28 Diagram illustrating longitudinal aberration at close focusing distance. Figure 29The diagram illustrates the lateral aberration of the imaging optical system 6 according to Example 6 when focusing at infinity. Figure 30 The diagram illustrates the lateral aberration of the imaging optical system 6 according to Example 6 when focusing at a close distance.

[0314] As can be appreciated from each aberration diagram, the imaging optical system 6 according to Example 6 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0315] [Example 7]

[0316] Table 31 shows the Figure 31 Table 32 shows the basic lens data of the imaging optical system 7 of Example 7 illustrated in Table 32. Table 32 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 7 according to Example 7. Table 33 shows the data of the surface spacing that is variable when focusing in the imaging optical system 7 according to Example 7. It should be noted that Table 32 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 33 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 34 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 7 according to Example 7. Table 35 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 7 according to Example 7.

[0317] The imaging optical system 7 according to Example 7 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0318] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0319] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L14 and an aperture stop St. In the imaging optical system 7 according to Example 7, lens L11 corresponds to the first negative lens Gnf, lenses L12 and L13 correspond to the first cemented lens, and lens L14 corresponds to the first positive lens. Furthermore, in the imaging optical system 7 according to Example 7, lenses L11 to L13 correspond to the first split lens group G1a, and lens L14 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0320] The second lens group G2 has negative refractive power and includes a lens L21.

[0321] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 7 according to Example 7, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0322] [Table 31]

[0323]

[0324]

[0325] [Table 32]

[0326]

[0327]

[0328] [Table 33]

[0329]

[0330] [Table 34]

[0331]

[0332] [Table 35]

[0333]

[0334] Figure 32 The diagram illustrates longitudinal aberration of the imaging optical system 7 according to Example 7 when focusing at infinity at the wide-angle end. Figure 33 Diagram illustrating longitudinal aberration at close focusing distance. Figure 34 The diagram illustrates the lateral aberration of the imaging optical system 7 according to Example 7 when focusing at infinity. Figure 35 The diagram illustrates the lateral aberration of the imaging optical system 7 according to Example 7 when focusing at a close distance.

[0335] As can be appreciated from each aberration diagram, the imaging optical system 7 according to Example 7 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0336] [Example 8]

[0337] Table 36 shows the Figure 36Table 37 shows the basic lens data of the imaging optical system 8 of Example 8 illustrated in FIG. Table 37 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 8 according to Example 8. Table 38 shows the data of the surface spacing that is variable when focusing in the imaging optical system 8 according to Example 8. It should be noted that Table 37 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 38 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 39 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 8 according to Example 8. Table 40 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 8 according to Example 8.

[0338] The imaging optical system 8 according to Example 8 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0339] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0340] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16 and an aperture stop St. In the imaging optical system 8 according to Example 8, lens L13 corresponds to the first negative lens Gnf, lenses L14 and L15 correspond to the first cemented lens, and lens L16 corresponds to the first positive lens. Furthermore, in the imaging optical system 8 according to Example 8, lenses L11 to L15 correspond to the first split lens group G1a, and lens L16 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0341] The second lens group G2 has negative refractive power and includes lenses L21 to L23.

[0342] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 8 according to Example 8, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0343] [Table 36]

[0344]

[0345]

[0346] [Table 37]

[0347]

[0348] [Table 38]

[0349]

[0350]

[0351] [Table 39]

[0352]

[0353] [Table 40]

[0354]

[0355]

[0356] Figure 37 The diagram illustrates longitudinal aberration of the imaging optical system 8 according to Example 8 when focusing at infinity at the wide-angle end. Figure 38 Diagram illustrating longitudinal aberration at close focusing distance. Figure 39 The diagram illustrates the lateral aberration of the imaging optical system 8 according to Example 8 when focusing at infinity. Figure 40 The diagram illustrates the lateral aberration of the imaging optical system 8 according to Example 8 when focusing at a close distance.

[0357] As can be appreciated from each aberration diagram, the imaging optical system 8 according to Example 8 undergoes good correction of various aberrations and therefore has excellent imaging performance.

[0358] [Example 9]

[0359] Table 41 shows the Figure 41Table 42 shows the basic lens data of the imaging optical system 9 of Example 9 illustrated in Table 42. Table 42 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 9 according to Example 9. Table 43 shows the data of the surface spacing that is variable when focusing in the imaging optical system 9 according to Example 9. It should be noted that Table 42 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 43 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 44 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 9 according to Example 9. Table 45 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 9 according to Example 9.

[0360] The imaging optical system 9 according to Example 9 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0361] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0362] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16 and an aperture stop St. In the imaging optical system 9 according to Example 9, lens L13 corresponds to the first negative lens Gnf, lenses L14 and L15 correspond to the first cemented lens, and lens L16 corresponds to the first positive lens. Furthermore, in the imaging optical system 9 according to Example 9, lenses L11 to L15 correspond to the first split lens group G1a, and lens L16 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0363] The second lens group G2 has negative refractive power and includes lenses L21 to L23.

[0364] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 9 according to Example 9, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0365] [Table 41]

[0366]

[0367]

[0368] [Table 42]

[0369]

[0370] [Table 43]

[0371]

[0372] [Table 44]

[0373]

[0374] [Table 45]

[0375]

[0376] Figure 42 The diagram illustrates longitudinal aberration of the imaging optical system 9 according to Example 9 when focusing at infinity at the wide-angle end. Figure 43 Diagram illustrating longitudinal aberration at close focusing distance. Figure 44 The diagram illustrates the lateral aberration of the imaging optical system 9 according to Example 9 when focusing at infinity. Figure 45 The diagram illustrates the lateral aberration of the imaging optical system 9 according to Example 9 when focusing at a close distance.

[0377] As can be appreciated from each aberration diagram, the imaging optical system 9 according to Example 9 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0378] [Example 10]

[0379] Table 46 shows the Figure 46 Basic lens data of the imaging optical system 10 of Example 10 illustrated in Table 47. Table 47 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y, and total optical length L of the entire system in the imaging optical system 10 according to Example 10. Table 48 shows data of the surface spacing that is variable when focusing in the imaging optical system 10 according to Example 10. It should be noted that Table 47 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 48 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 49 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 10 according to Example 10. Table 50 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 10 according to Example 10.

[0380] The imaging optical system 10 according to Example 10 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0381] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0382] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16 and an aperture stop St. In the imaging optical system 10 according to Example 10, lens L13 corresponds to the first negative lens Gnf, lenses L14 and L15 correspond to the first cemented lens, and lens L16 corresponds to the first positive lens. Furthermore, in the imaging optical system 10 according to Example 10, lenses L11 to L15 correspond to the first split lens group G1a, and lens L16 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0383] The second lens group G2 has negative refractive power and includes lenses L21 to L23.

[0384] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 10 according to Example 10, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0385] [Table 46]

[0386]

[0387]

[0388] [Table 47]

[0389]

[0390] [Table 48]

[0391]

[0392] [Table 49]

[0393]

[0394]

[0395] [Table 50]

[0396]

[0397] Figure 47 The diagram illustrates longitudinal aberration of the imaging optical system 10 according to Example 10 when focusing at infinity at the wide-angle end. Figure 48 Diagram illustrating longitudinal aberration at close focusing distance. Figure 49 The diagram illustrates the lateral aberration of the imaging optical system 10 according to Example 10 when focusing at infinity. Figure 50 The diagram illustrates the lateral aberration of the imaging optical system 10 according to Example 10 when focusing at a close distance.

[0398] As can be appreciated from each aberration diagram, the imaging optical system 10 according to Example 10 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0399] [Example 11]

[0400] Table 51 shows the Figure 51 Table 52 shows the basic lens data of the imaging optical system 11 of Example 11 illustrated in FIG. Table 52 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y and total optical length L of the entire system in the imaging optical system 11 according to Example 11. Table 53 shows the data of the surface spacing that is variable when focusing in the imaging optical system 11 according to Example 11. It should be noted that Table 52 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 53 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 54 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 11 according to Example 11. Table 55 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 11 according to Example 11.

[0401] The imaging optical system 11 according to Example 11 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0402] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0403] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16 and an aperture stop St. In the imaging optical system 11 according to Example 11, lens L13 corresponds to the first negative lens Gnf, lenses L14 and L15 correspond to the first cemented lens, and lens L16 corresponds to the first positive lens. Furthermore, in the imaging optical system 11 according to Example 11, lenses L11 to L15 correspond to the first split lens group G1a, and lens L16 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0404] The second lens group G2 has negative refractive power and includes lenses L21 to L23.

[0405] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L34. In the imaging optical system 11 according to Example 11, lens L31 corresponds to the second positive lens, lenses L32 and L33 correspond to the second cemented lens, and lens L34 corresponds to the second negative lens Gnr. In the third lens group G3, the second air lens Gar, which has negative refractive power, is formed by the second cemented lens and the second negative lens Gnr.

[0406] [Table 51]

[0407]

[0408]

[0409] [Table 52]

[0410]

[0411] [Table 53]

[0412]

[0413] [Table 54]

[0414]

[0415]

[0416] [Table 55]

[0417]

[0418] Figure 52 The diagram illustrates longitudinal aberration of the imaging optical system 11 according to Example 11 when focusing at infinity at the wide-angle end. Figure 53Diagram illustrating longitudinal aberration at close focusing distance. Figure 54 The diagram illustrates the lateral aberration of the imaging optical system 11 according to Example 11 when focusing at infinity. Figure 55 The diagram illustrates the lateral aberration of the imaging optical system 11 according to Example 11 when focusing at a close distance.

[0419] As can be appreciated from each aberration diagram, the imaging optical system 11 according to Example 11 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0420] [Example 12]

[0421] Table 56 shows the Figure 56 Basic lens data of the imaging optical system 12 of Example 12 illustrated in Table 57. Table 57 shows the values ​​of the focal length f, F value, total field angle 2ω, image height Y, and total optical length L of the entire system in the imaging optical system 12 according to Example 12. Table 58 shows data of the surface spacing that is variable when focusing in the imaging optical system 12 according to Example 12. It should be noted that Table 57 shows the values ​​when the shooting distance and the object distance (d0) are both infinite. Table 58 shows the values ​​when the shooting distance and the object distance (d0) are both infinite, and when the shooting distance and the object distance (d0) are both close. Table 59 shows the values ​​of the coefficients indicating the shape of the aspheric surface in the imaging optical system 12 according to Example 12. Table 60 shows the starting surface and focal length (unit: mm) of each lens group of the imaging optical system 12 according to Example 12.

[0422] The imaging optical system 12 according to Example 12 has a configuration in which a first lens group G1, a second lens group G2, and a third lens group G3, which is the final lens group positioned closest to the image plane, are arranged in this order from the object side to the image plane side. An aperture stop St is arranged in the first lens group G1. An optical member GC is arranged between the third lens group G3 and the image plane.

[0423] When focusing from infinity to a close distance, the first lens group G1 and the third lens group G3 are both fixed relative to the image plane, while the second lens group G2 moves parallel to the image plane in the optical axis direction.

[0424] The first lens group G1 has positive refractive power. The first lens group G1 includes, in order from the object side to the image side, lenses L11 to L16 and an aperture stop St. In the imaging optical system 12 according to Example 12, lens L13 corresponds to the first negative lens Gnf, lenses L14 and L15 correspond to the first cemented lens, and lens L16 corresponds to the first positive lens. Furthermore, in the imaging optical system 12 according to Example 12, lenses L11 to L15 correspond to the first split lens group G1a, and lens L16 corresponds to the second split lens group G1b. In the first lens group G1, a first air lens Gaf having negative refractive power is formed by the first negative lens Gnf and the first cemented lens.

[0425] The second lens group G2 has negative refractive power and includes lenses L21 to L23.

[0426] The third lens group G3 has positive refractive power. The third lens group G3 includes lenses L31 to L33. In the imaging optical system 12 according to Example 12, lenses L31 and L32 correspond to a second cemented lens, while lens L33 corresponds to a second negative lens Gnr. In the third lens group G3, a second air lens Gar having negative refractive power is formed by the second cemented lens and the second negative lens Gnr.

[0427] [Table 56]

[0428]

[0429]

[0430] [Table 57]

[0431]

[0432]

[0433] [Table 58]

[0434]

[0435] [Table 59]

[0436]

[0437] [Table 60]

[0438]

[0439] Figure 57 The diagram illustrates longitudinal aberration of the imaging optical system 12 according to Example 12 when focusing at infinity at the wide-angle end. Figure 58 Diagram illustrating longitudinal aberration at close focusing distance. Figure 59The diagram illustrates the lateral aberration of the imaging optical system 12 according to Example 12 when focusing at infinity. Figure 60 The diagram illustrates the lateral aberration of the imaging optical system 12 according to Example 12 when focusing at a close distance.

[0440] As can be appreciated from each aberration diagram, the imaging optical system 12 according to Example 12 undergoes good correction of various aberrations and thus has excellent imaging performance.

[0441] [Other numerical data for each example]

[0442] Tables 61 and 62 summarize the values ​​associated with each of the above conditional expressions for each example. It can be appreciated from Tables 61 and 62 that, for each conditional expression, the value of each example falls within the corresponding numerical range.

[0443] [Table 61]

[0444]

[0445]

[0446] [Table 62]

[0447]

[0448] <5. Practical Application Examples>

[0449] [5.1 First practical application example]

[0450] The technology disclosed herein is applicable to a variety of products. For example, the technology disclosed herein can be implemented as a device mounted on any type of mobile object, including automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, aircraft, drones, ships, robots, construction machinery, and agricultural machinery (tractors).

[0451] Figure 62 7010 is a block diagram illustrating an example of a schematic configuration of a vehicle control system 7000 as an example of a mobile control system to which the technology according to an embodiment of the present disclosure is applicable. The vehicle control system 7000 includes a plurality of electronic control units interconnected via a communication network 7010. Figure 62In the example depicted in FIG, a vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an external information detection unit 7400, an internal information detection unit 7500, and an integrated control unit 7600. A communication network 7010 that interconnects the plurality of control units may be, for example, an in-vehicle communication network that complies with any standard such as a controller area network (CAN), a local interconnect network (LIN), a local area network (LAN), or FlexRay (registered trademark).

[0452] Each control unit includes a microcomputer that performs arithmetic processing according to various programs; a storage unit that stores programs executed by the microcomputer, parameters used for various operations, and the like; and a drive circuit that drives various control target devices. Each control unit also includes a network interface (I / F) for communicating with other control units via the communication network 7010; and a communication I / F for communicating with devices and sensors inside and outside the vehicle via wired or radio communication. Figure 62 The functional configuration of the integrated control unit 7600 illustrated in FIG includes a microcomputer 7610, a general communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, a sound / image output unit 7670, an in-vehicle network I / F 7680, and a storage unit 7690. Other control units similarly include a microcomputer, a communication I / F, a storage unit, and the like.

[0453] The drive system control unit 7100 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 7100 functions as a control device for drive force generation devices such as an internal combustion engine and a drive motor that generate the vehicle's drive force; a drive force transmission mechanism that transmits the drive force to the wheels; a steering mechanism that adjusts the vehicle's steering angle; and a braking system that generates the vehicle's braking force. The drive system control unit 7100 can also function as a control device for devices such as an anti-lock braking system (ABS) and an electronic stability control (ESC).

[0454] Drive system control unit 7100 is connected to vehicle state detection unit 7110. For example, vehicle state detection unit 7110 includes at least one of a gyro sensor for detecting the angular velocity of the axial rotational motion of the vehicle body, an acceleration sensor for detecting vehicle acceleration, and sensors for detecting the amount of accelerator pedal operation, amount of brake pedal operation, steering wheel angle, engine speed, wheel speed, and the like. Drive system control unit 7100 performs arithmetic processing using the signals input from vehicle state detection unit 7110 to control the internal combustion engine, drive motor, electric power steering system, braking system, and the like.

[0455] The body system control unit 7200 controls the operation of various devices attached to the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, power windows, or various vehicle lights such as headlights, backup lights, brake lights, turn signals, or fog lights. In this case, radio waves transmitted from a mobile device that replaces a key or signals from various switches can be input to the body system control unit 7200. The body system control unit 7200 receives these input radio waves or signals and controls the vehicle's door locks, power windows, lights, and other functions.

[0456] Battery control unit 7300 controls battery 7310, which serves as the power supply source for the drive motor, according to various programs. For example, information regarding battery temperature, battery output voltage, and remaining battery charge is supplied to battery control unit 7300 from the battery device including battery 7310. Battery control unit 7300 performs arithmetic processing using these signals and controls for adjusting the temperature of battery 7310 or controlling cooling equipment provided to the battery device.

[0457] The vehicle exterior information detection unit 7400 detects information about the exterior of the vehicle including the vehicle control system 7000. For example, the vehicle exterior information detection unit 7400 is connected to at least one of the imaging unit 7410 and the vehicle exterior information detection unit 7420. The imaging unit 7410 includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The vehicle exterior information detection unit 7420 includes, for example, an environmental sensor for detecting current atmospheric or meteorological conditions, and at least one of a surrounding information detection sensor for detecting other vehicles, obstacles, pedestrians, and the like around the vehicle including the vehicle control system 7000.

[0458] The environmental sensor may be, for example, at least one of a raindrop sensor for detecting rain, a fog sensor for detecting fog, a sunshine sensor for detecting sunshine intensity, and a snow sensor for detecting snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR device (a light detection and ranging device, or a laser imaging detection and ranging device). The imaging unit 7410 and the vehicle exterior information detection unit 7420 may each be configured as an independent sensor or device, or may be configured as a device in which multiple sensors or devices are integrated.

[0459] Figure 63The following illustrates examples of installation locations for the imaging unit 7410 and the vehicle exterior information detection unit 7420. Imaging units 7910, 7912, 7914, 7916, and 7918 are positioned, for example, at least one of the front nose, exterior mirrors, rear bumper, and rear doors of the vehicle 7900, as well as the upper portion of the windshield within the vehicle. Imaging unit 7910 located at the front nose and imaging unit 7918 located at the upper portion of the windshield within the vehicle primarily capture images in front of the vehicle 7900. Imaging units 7912 and 7914 located in the exterior mirrors primarily capture images to the sides of the vehicle 7900. Imaging unit 7916 located in the rear bumper or rear door primarily captures images from behind the vehicle 7900. Imaging unit 7918 located at the upper portion of the windshield within the vehicle primarily detects vehicles ahead, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.

[0460] By the way, Figure 63 Depicted are examples of the imaging ranges of imaging units 7910, 7912, 7914, and 7916. Imaging range a represents the imaging range of imaging unit 7910, located at the front nose. Imaging ranges b and c represent the imaging ranges of imaging units 7912 and 7914, respectively, located at the exterior rearview mirrors. Imaging range d represents the imaging range of imaging unit 7916, located at the rear bumper or rear door. For example, by superimposing the image data captured by imaging units 7910, 7912, 7914, and 7916, a bird's-eye view of vehicle 7900 can be obtained from above.

[0461] The exterior information detection units 7920, 7922, 7924, 7926, 7928, and 7930 located at the front, rear, sides, and corners of the vehicle 7900, as well as above the windshield inside the vehicle, may be, for example, ultrasonic sensors or radar devices. The exterior information detection units 7920, 7926, and 7930 located at the front nose, rear bumper, rear doors, and above the windshield inside the vehicle 7900 may be, for example, LIDAR devices. These exterior information detection units 7920 and 7930 are primarily used to detect preceding vehicles, pedestrians, obstacles, and the like.

[0462] return Figure 62, continue to describe. The outside vehicle information detection unit 7400 causes the imaging unit 7410 to image the outside of the vehicle and receive the imaged image data. In addition, the outside vehicle information detection unit 7400 receives detection information from the outside vehicle information detection unit 7420 connected to the outside vehicle information detection unit 7400. In the case where the outside vehicle information detection unit 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the outside vehicle information detection unit 7400 transmits ultrasonic waves, electromagnetic waves, etc., and receives information of the received reflected waves. Based on the received information, the outside vehicle information detection unit 7400 can perform processing to detect objects such as people, vehicles, obstacles, signs, or text on the road surface, or detect the distance to the object. The outside vehicle information detection unit 7400 can perform environmental recognition processing to identify rainfall, fog, road conditions, etc. based on the received information. The outside vehicle information detection unit 7400 can calculate the distance to objects outside the vehicle based on the received information.

[0463] In addition, based on the received image data, the vehicle exterior information detection unit 7400 can perform image recognition processing to identify people, vehicles, obstacles, signs, or text on the road, or detect the distance thereto. The vehicle exterior information detection unit 7400 can perform processing such as distortion correction and alignment on the received image data, and can combine image data imaged by multiple different imaging units 7410 to generate a bird's-eye view image or a panoramic image. The vehicle exterior information detection unit 7400 can use image data imaged by the imaging unit 7410 including different imaging components to perform viewpoint conversion processing.

[0464] The in-vehicle information detection unit 7500 detects information about the interior of the vehicle. The in-vehicle information detection unit 7500 is connected to, for example, a driver state detection unit 7510 that detects the state of the driver. The driver state detection unit 7510 may include a camera that images the driver, a biosensor that detects the driver's biometric information, a microphone that collects sounds inside the vehicle, and the like. The biosensor is, for example, arranged on a seat surface or a steering wheel, and detects biometric information of a passenger sitting on the seat or a driver holding the steering wheel. Based on the detection information input from the driver state detection unit 7510, the in-vehicle information detection unit 7500 can calculate the driver's fatigue or the driver's concentration, or can determine whether the driver is dozing off. The in-vehicle information detection unit 7500 can perform processing such as noise cancellation processing on the audio signal obtained by collecting the sound.

[0465] The integrated control unit 7600 controls all operations within the vehicle control system 7000 according to various programs. The integrated control unit 7600 is connected to the input unit 7800. The input unit 7800 is implemented using a device such as a touch panel, buttons, microphone, switch, or joystick that allows for input operations by the occupant. The integrated control unit 7600 can be supplied with data obtained through voice recognition of speech input via the microphone. The input unit 7800 can be, for example, a remote control device using infrared or other radio waves, or an externally connected device that supports the operation of the vehicle control system 7000, such as a mobile phone or personal digital assistant (PDA). The input unit 7800 can be, for example, a camera. In this case, the occupant can input information through gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the occupant can be input. Furthermore, the input unit 7800 can include, for example, an input control circuit that generates an input signal based on information input by the occupant, etc., using the input unit 7800, and outputs the generated input signal to the integrated control unit 7600. Passengers and the like input various data or command processing operations to the vehicle control system 7000 by operating the input unit 7800 .

[0466] The storage unit 7690 may include a read-only memory (ROM) for storing various programs executed by the microcomputer, and a random access memory (RAM) for storing various parameters, operation results, sensor values, etc. In addition, the storage unit 7690 may be implemented by a magnetic storage device such as a hard disk drive (HDD), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

[0467] Universal communication I / F 7620 is a widely used communication I / F that mediates communication with various devices present in external environment 7750. Universal communication I / F 7620 can implement cellular communication protocols such as Global System for Mobile Communications (GSM (registered trademark)), Worldwide Interoperability for Microwave Access (WiMAX (registered trademark)), Long Term Evolution (LTE (registered trademark)), or LTE-Advanced (LTE-A), or other wireless communication protocols such as wireless LAN (also known as Wireless Fidelity (Wi-Fi (registered trademark)) or Bluetooth (registered trademark). Universal communication I / F 7620 can connect to devices (e.g., application servers or control servers) present on an external network (e.g., the Internet, a cloud network, or a company's private network) via a base station or access point, for example. In addition, universal communication I / F 7620 can connect to terminals near the vehicle (e.g., terminals of the driver, pedestrians, or stores, or machine type communication (MTC) terminals), for example, using peer-to-peer (P2P) technology.

[0468] Dedicated communication I / F 7630 is a communication I / F that supports communication protocols developed for use in vehicles. For example, dedicated communication I / F 7630 can implement standard protocols such as Wireless Access in Vehicular Environments (WAVE), a combination of Institute of Electrical and Electronics Engineers (IEEE) 802.11p as a lower layer and IEEE 1609 as an upper layer, dedicated short-range communication (DSRC), or cellular communication protocols. Dedicated communication I / F 7630 generally performs V2X communication, which is a concept that includes one or more of vehicle-to-vehicle (V2V) communication, road-to-vehicle (V2I) communication, vehicle-to-residence (V2R) communication, and pedestrian-to-vehicle (V2P) communication.

[0469] The positioning unit 7640 performs positioning by, for example, receiving GNSS signals from a global navigation satellite system (GNSS) satellite (e.g., a GPS signal from a global positioning system (GPS) satellite) and generates position information including the latitude, longitude, and altitude of the vehicle. Incidentally, the positioning unit 7640 may identify the current position by exchanging signals with a wireless access point, or may obtain position information from a terminal having a positioning function, such as a mobile phone, a personal handyphone system (PHS), or a smartphone.

[0470] Beacon receiving unit 7650 receives radio waves or electromagnetic waves transmitted from wireless stations installed on roads, etc., and thereby obtains information on the current position, congestion, closed roads, required time, etc. Incidentally, the function of beacon receiving unit 7650 may be included in the above-mentioned dedicated communication I / F 7630.

[0471] The in-vehicle device I / F 7660 is a communication interface that mediates the connection between the microcomputer 7610 and the various in-vehicle devices 7760 present in the vehicle. The in-vehicle device I / F 7660 can establish a wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), near field communication (NFC), or wireless universal serial bus (WUSB). In addition, the in-vehicle device I / F 7660 can establish a wired connection via a universal serial bus (USB), a high-definition multimedia interface (HDMI (registered trademark)), or a mobile high-definition link (MHL) via a connection terminal (and a cable, if necessary) not shown in the figure. The in-vehicle device 7760 can, for example, include at least one of a mobile device and a wearable device owned by the occupant and an information device brought into or attached to the vehicle. The in-vehicle device 7760 may also include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I / F 7660 exchanges control signals or data signals with these in-vehicle devices 7760.

[0472] The in-vehicle network I / F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals and the like in compliance with a predetermined protocol supported by the communication network 7010.

[0473] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 according to various programs based on information obtained via at least one of the general communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. For example, the microcomputer 7610 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information obtained about the interior and exterior of the vehicle, and output control commands to the drive system control unit 7100. For example, the microcomputer 7610 can perform coordinated control to implement advanced driver assistance system (ADAS) functions, such as vehicle collision avoidance or shock absorption, follow-up driving based on following distance, vehicle speed control, vehicle collision warning, vehicle lane departure warning, and the like. In addition, the microcomputer 7610 can control the driving force generating device, steering mechanism, braking device, etc. based on the information obtained about the vehicle's surrounding environment, and perform collaborative control for the purpose of automatic driving, etc., so that the vehicle can drive autonomously without relying on the driver's operation.

[0474] Based on information obtained via at least one of the general communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiver 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680, the microcomputer 7610 can generate three-dimensional distance information between the vehicle and objects such as surrounding buildings and people, and generate local map information including information about the surrounding environment of the vehicle's current location. Furthermore, based on the obtained information, the microcomputer 7610 can predict dangers such as a vehicle collision, the approach of pedestrians, or entering a closed road, and generate an alarm signal. The alarm signal can, for example, generate an alarm sound or illuminate a warning light.

[0475] The sound / image output unit 7670 transmits an output signal of sound and / or image to an output device capable of visually or audibly notifying the occupants of the vehicle or the outside of the vehicle of information. Figure 62In the example of , an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are illustrated as output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an augmented reality (AR) display function. The output device may be different from these devices and may be other devices, such as headphones, wearable devices such as glasses-type displays worn by passengers, projectors, or lights. In the case where the output device is a display device, the display device visually displays the results obtained by various processes performed by the microcomputer 7610, or information received from other control units, in various forms such as text, images, tables, or graphics. In addition, in the case where the output device is an audio output device, the audio output device converts an audio signal consisting of reproduced audio data or sound data into an analog signal and then audibly outputs the analog signal.

[0476] Incidentally, in Figure 62 In the example depicted in , at least two control units connected to each other via the communication network 7010 can be integrated into one control unit. Alternatively, each individual control unit may include multiple control units. In addition, the vehicle control system 7000 may include other control units not depicted in the figure. In addition, part or all of the functions performed by one of the control units in the above description can be assigned to other control units. That is, as long as information is sent and received via the communication network 7010, predetermined arithmetic processing can be performed by any control unit. Similarly, a sensor or device connected to one of the control units can be connected to other control units, and multiple control units can send and receive detection information to each other via the communication network 7010.

[0477] In the above-mentioned vehicle control system 7000 , the imaging optical system and the imaging device of the present disclosure are applicable to the imaging section 7410 and any of the imaging sections 7910 , 7912 , 7914 , 7916 and 7918 .

[0478] [5.2 Second practical application example]

[0479] The technology according to the present disclosure is applicable to medical imaging systems. A medical imaging system is a medical system that uses imaging technology, such as an endoscope system or a microscope system.

[0480] [Endoscope System]

[0481] Will use Figure 64 and Figure 65 Describe an example of an endoscope system. Figure 64 1 is a diagram illustrating an example of a schematic configuration of an endoscope system 5000 to which the technology according to the present disclosure is applied. Figure 65It is a diagram illustrating an example of the configuration of an endoscope 5001 and a camera control unit (CCU) 5039. Figure 64 The diagram illustrates a situation in which an operator (eg, doctor) 5067 as a surgical participant uses an endoscope system 5000 to perform surgery on a patient 5071 on a bed 5069. Figure 64 As shown in the diagram, an endoscope system 5000 includes an endoscope 5001 as a medical imaging device, a CCU 5039 , a light source device 5043 , a recording device 5053 , an output device 5055 , and a support device 5027 for supporting the endoscope 500 .

[0482] In endoscopic surgery, an insertion aid tool called a trocar 5025 is inserted into the body of a patient 5071. Then, a scope 5003 connected to an endoscope 5001 and surgical tools 5021 are inserted into the body of the patient 5071 via the trocar 5025. The surgical tools 5021 include: an energy device such as an electric knife; and forceps, for example.

[0483] A surgical image, which is a medical image captured inside the body of a patient 5071 through an endoscope 5001, is displayed on a display device 5041. An operator 5067 performs surgery on a surgical target using a surgical tool 5021 while viewing the surgical image displayed on the display device 5041. The medical image is not limited to a surgical image and may be a diagnostic image captured during diagnosis.

[0484] [Endoscope]

[0485] The endoscope 5001 is an imaging part for capturing the inside of the body of the patient 5071, and is used for example Figure 65As shown in the diagram, the camera includes a focusing optical system 50051 for converging incident light, a zoom optical system 50052 capable of optical zooming by changing the focal length of the imaging unit, a focusing optical system 50053 capable of adjusting the focus by changing the focal length of the imaging unit, and a light-receiving sensor 50054. The endoscope 5001 converges light passing through the connected lens barrel 5003 onto the light-receiving sensor 50054 to generate pixel signals, which are then output to the CCU 5039 via a transmission system. The lens barrel 5003 is an insertable portion that includes an objective lens at its distal end and guides light from a connected light source device 5043 into the body of a patient 5071. The lens barrel 5003 may be, for example, a rigid lens barrel for a rigid endoscope or a flexible lens barrel for a flexible endoscope. The lens barrel 5003 may be a direct-view lens barrel or an oblique-view lens barrel. The pixel signals may be based on signals output from the pixels and may be, for example, raw signals or image signals. The transmission system that connects the endoscope 5001 to the CCU 5039 may include a memory, and the memory may store parameters related to the endoscope 5001 and the CCU 5039. The memory may be arranged on a connecting portion or cable of the transmission system. For example, the memory of the transmission system may store parameters of the endoscope 5001 before shipment or parameters that change when current is applied, and the operation of the endoscope may be changed based on the parameters read from the memory. The set of the camera and the transmission system may be referred to as an endoscope. The light receiving sensor 50054 is a sensor for converting received light into a pixel signal, and is, for example, a complementary metal oxide semiconductor (CMOS) imaging sensor. The light receiving sensor 50054 is preferably an imaging sensor capable of color imaging having a Bayer array. The light-receiving sensor 50054 is also preferably an imaging sensor having a number of pixels corresponding to a resolution of, for example, 4K (3840 horizontal pixels × 2160 vertical pixels), 8K (7680 horizontal pixels × 4320 vertical pixels), or square 4K (3840 or more horizontal pixels × 3840 or more vertical pixels). The light-receiving sensor 50054 may be one sensor chip, or may be a plurality of sensor chips. For example, a prism may be provided to separate incident light into predetermined wavelength bands, and these wavelength bands may be imaged by different light-receiving sensors. A plurality of light-receiving sensors may be provided for stereoscopic viewing. The light-receiving sensor 50054 may be a sensor having a chip structure including an arithmetic processing circuit for image processing, or may be a sensor for time of flight (ToF). The transmission system is, for example, an optical fiber cable system or a wireless transmission system. Wireless transmission only needs to be able to transmit the pixel signal generated by the endoscope 5001. For example, the endoscope 5001 can be wirelessly connected to the CCU 5039, or the endoscope 5001 can be connected to the CCU 5039 via a base station in the operating room.At this time, the endoscope 5001 can not only send pixel signals, but also simultaneously send information related to the pixel signals (e.g., processing priority of the pixel signals and / or synchronization signals). In the endoscope, the lens barrel can be integrated with the camera head, and the light sensor can be set at the far end of the lens barrel.

[0486] [Camera Control Unit (CCU)]

[0487] The CCU 5039 is a control device for controlling the endoscope 5001 and the light source device 5043 connected to the CCU 5039 in an integrated manner, and is, for example, Figure 65 As shown in the diagram, the image processing device includes a field programmable gate array (FPGA) 50391, a central processing unit (CPU) 50392, a random access memory (RAM) 50393, a read-only memory (ROM) 50394, a graphics processing unit (GPU) 50395, and an interface (I / F) 50396. The CCU 5039 can control the display device 5041, the recording device 5053, and the output device 5055 connected to the CCU 5039 in an integrated manner. The CCU 5039 controls, for example, the illumination timing, illumination intensity, and type of illumination light source of the light source device 5043. The CCU 5039 also performs image processing such as development processing (e.g., demosaicing processing) and correction processing on the pixel signals output from the endoscope 5001, and outputs the processed image signals (e.g., images) to an external device such as the display device 5041. The CCU 5039 also sends control signals to the endoscope 5001 to control the driving of the endoscope 5001. The control signal is information about imaging conditions, such as the magnification or focal length of the imaging unit. The CCU 5039 may have a function of down-converting images and may be configured to simultaneously output a higher resolution (e.g., 4K) image to the display device 5041 and a lower resolution (e.g., high definition (HD)) image to the recording device 5053.

[0488] The CCU 5039 can be connected to external devices (such as recording devices, display devices, output devices, and support devices) via an IP converter for converting signals into a predetermined communication protocol (such as the Internet Protocol (IP)). The connection between the IP converter and the external device can be established using a wired network, or part or all of the network can be established using a wireless network. For example, the IP converter on the CCU 5039 side can have a wireless communication function and can send the received image to the IP switch or the output-side IP converter via a wireless communication network such as a fifth-generation mobile communication system (5G) or a sixth-generation mobile communication system (6G).

[0489] [Light source equipment]

[0490] The light source device 5043 is a device capable of emitting light having a predetermined wavelength band, and for example includes multiple light sources and a light source optical system for guiding the light from the light sources. The light source is, for example, a xenon lamp, a light-emitting diode (LED) light source, or a laser diode (LD) light source. The light source device 5043 includes, for example, LED light sources corresponding to the three primary colors of red (R), green (G), and blue (B), and controls the output intensity and output timing of each light source to emit white light. In addition to a light source for emitting ordinary light for ordinary light observation, the light source device 5043 may also include a light source capable of emitting special light for special light observation. Special light is light having a predetermined wavelength band different from ordinary light used for ordinary light observation, and for example, is near-infrared light (light with a wavelength of 760 nm or more), infrared light, blue light, or ultraviolet light. Ordinary light is, for example, white light or green light. In narrowband imaging, a type of special light observation, blue light and green light are emitted alternately. Therefore, narrowband imaging can use the wavelength dependence of light absorption in body tissue to image predetermined tissues, such as blood vessels in mucosal surfaces, with high contrast. In fluorescence observation, which is a type of special light observation, excitation light is emitted to excite the reagent injected into the body tissue, and fluorescence emitted by the body tissue or the reagent used as a marker is received to obtain a fluorescence image. Therefore, fluorescence observation can facilitate the operator to observe body tissues that are difficult for the operator to observe using ordinary light. For example, in fluorescence observation using infrared light, infrared light with an excitation band is emitted to the reagent injected into the body tissue, such as indocyanine green (ICG), and fluorescence from the reagent is received, so that fluorescence observation can facilitate the observation of the structure of the body tissue and the affected part. In fluorescence observation, a reagent (such as 5-aminolevulinic acid (5-ALA)) that emits fluorescence in the red band by being excited with special light in the blue band can be used. The type of irradiation light of the light source device 5043 is set by the control of the CCU 5039. The CCU 5039 can have a mode for controlling the light source device 5043 and the endoscope 5001 to alternately perform ordinary light observation and special light observation. At this time, information based on the pixel signal obtained by special light observation is preferably superimposed on the pixel signal obtained by ordinary light observation. Special light observation can include infrared light observation for observing the surface and interior of organs, and multispectral observation using hyperspectral spectroscopy. It can also be combined with photodynamic therapy.

[0491] [Recording Equipment]

[0492] The recording device 5053 is a device for recording pixel signals (e.g., images) acquired from the CCU 5039, such as a recorder. The recording device 5053 records the images acquired from the CCU 5039 to a hard disk drive (HDD), an ultra-high-density disk (SDD), and / or an optical disk. The recording device 5053 can be connected to a network within the hospital so that it can be accessed from a device outside the operating room. The recording device 5053 can have a down-conversion function or an up-conversion function.

[0493] [Display device]

[0494] The display device 5041 is a device capable of displaying images, such as a display monitor. The display device 5041 displays an image based on pixel signals acquired from the CCU 5039. The display device 5041 may include a camera and a microphone to serve as an input device that allows command input through gaze recognition, voice recognition, and gestures.

[0495] [output device]

[0496] The output device 5055 is a device, such as a printer, for outputting information acquired from the CCU 5039. The output device 5055 prints a print image based on the pixel signal acquired from the CCU 5039 on paper, for example.

[0497] [Support equipment]

[0498] The support device 5027 is an articulated arm comprising a base 5029 containing an arm control device 5045, an arm 5031 extending from the base 5029, and a holding portion 5032 mounted at the distal end of the arm 5031. The arm control device 5045 includes a processor such as a CPU and operates according to a predetermined computer program to control the driving of the arm 5031. The support device 5027 uses the arm control device 5045 to control parameters such as the length of the link 5035 constituting the arm 5031 and the rotation angle and torque of the joint 5033, thereby controlling the position and posture of the endoscope 5001 held by the holding portion 5032. This control can change the position or posture of the endoscope 5001 to a desired position or posture, allowing the lens barrel 5003 to be inserted into the patient 5071 and changing the observation area within the body. The support device 5027 serves as an endoscope support arm for supporting the endoscope 5001 during surgery. Therefore, the support device 5027 can play the role of an endoscopist who is an assistant to the endoscope 5001. The support device 5027 can be a device for holding the microscope device 5301 described later, and can be called a medical support arm. The support device 5027 can be controlled using an autonomous control method by the arm control device 5045, or can be controlled using a control method in which the arm control device 5045 is controlled based on the input of the user. The control method can be, for example, a master-slave method in which the support device 5027, which acts as a slave device (secondary device) as a patient cart, is controlled based on the movement of a master device (primary device) as an operator's console in the hands of the user. The support device 5027 can be remotely controlled from outside the operating room.

[0499] An example of the endoscope system 5000 to which the technology according to the present disclosure is applied is described above. For example, the technology according to the present disclosure can be applied to a microscope system.

[0500] [Microscope system]

[0501] Figure 66 5 is a diagram illustrating an example of a schematic configuration of a microsurgery system to which the technology of the present disclosure is applicable. In the following description, the same components as those of the endoscope system 5000 will be denoted by the same reference numerals, and description thereof will not be repeated.

[0502] Figure 66 The diagram schematically illustrates a situation in which an operator 5067 uses a microsurgery system 5300 to perform surgery on a patient 5071 on a bed 5069. For simplicity, Figure 66The cart 5037 among the components of the microsurgery system 5300 is not illustrated, and the microscope device 5301 is simplified for illustration instead of the endoscope 5001. The microscope device 5301 may refer to the microscope 5303 provided at the distal end of the link 5035, or may refer to the entire configuration including the microscope 5303 and the support device 5027.

[0503] like Figure 66 As shown in the diagram, during surgery, a microsurgery system 5300 is used to display an enlarged image of a surgical site captured by a microscope device 5301 on a display device 5041 installed in an operating room. Display device 5041 is mounted facing an operator 5067, who performs various surgeries, such as excision, on the surgical site while observing the image displayed on display device 5041. Microsurgery systems are used, for example, in ophthalmic and neurosurgery procedures.

[0504] Corresponding examples of the endoscope system 5000 and the microsurgery system 5300 to which the technology of the present disclosure is applicable have been described above. The systems to which the technology of the present disclosure is applicable are not limited to such examples. For example, the support device 5027 can support other observation devices or other surgical tools at its distal end instead of the endoscope 5001 or the microscope 5303. Examples of other applicable observation devices include forceps, tweezers, a pneumoperitoneum tube for pneumoperitoneum, and an energy treatment tool for cutting tissue or sealing blood vessels by cauterization. By using a support device to support the above-mentioned observation device or surgical tool, its position can be fixed more stably and the burden on the medical staff is lower than in the case where the medical staff manually supports the observation device or surgical tool. The technology of the present disclosure can be applied to support devices that support such components other than microscopes.

[0505] The technology according to the present disclosure can be suitably applied to the camera 5005 in the above configuration. In particular, the imaging optical system of the present disclosure can be suitably applied to at least some of the optical systems of the condensing optical system 50051, the zoom optical system 50052, and the focusing optical system 50053 in the camera 5005.

[0506] <6. Other embodiments>

[0507] The technology according to the present disclosure is not limited to the description of the above embodiments and examples, and can be modified and implemented in various ways.

[0508] For example, the shapes and numerical values ​​of the corresponding parts illustrated in the above-mentioned embodiments and examples are merely examples of implementation of the present technology, and the technical scope of the present technology should not be interpreted as being limited by these examples.

[0509] Furthermore, for example, a configuration including a different number of lenses than those described in the aforementioned embodiments and examples may be employed. Furthermore, a configuration further including a lens having no substantial refractive power may be employed. Here, a lens having no substantial refractive power is a lens that, in principle, does not have refractive power that affects the optical performance achieved by the lens system. For example, a lens having no substantial refractive power is a flat plate lens.

[0510] For example, the present technology may also have the following configurations.

[0511] According to the present technology configured as follows, the configuration of each lens group is optimized to achieve minimal aberration variation associated with focusing, high optical performance throughout the entire focus range, and facilitate lightweighting of the focus movable portion. This makes it possible to provide an imaging optical system and an imaging device including such an imaging optical system, each of which achieves minimal aberration variation associated with focusing, high optical performance throughout the entire focus range, and facilitates lightweighting of the focus movable portion.

[0512] [1] An imaging optical system comprising, from the object side to the image side, the following:

[0513] a first lens group having positive refractive power;

[0514] a second lens group having negative refractive power; and

[0515] The final lens group has positive refractive power and is arranged on the side closest to the image plane, wherein

[0516] When focusing, the first lens group and the final lens group are both fixed, and the second lens group moves in the optical axis direction,

[0517] The first lens group includes a first negative lens, a first cemented lens in which a negative lens and a positive lens are cemented, and a first air lens having negative refractive power sandwiched between the first negative lens and the first cemented lens, and

[0518] The final lens group includes a second cemented lens in which a positive lens and a negative lens are cemented, a second negative lens, and a second air lens having negative refractive power sandwiched between the second cemented lens and the second negative lens.

[0519] [2] The imaging optical system according to [1], wherein the following conditional expression is also satisfied:

[0520] 0.5<|faf| / f<2.0......(1)

[0521] in

[0522] faf represents the focal length of the first air lens, and

[0523] f represents the focal length of the entire system.

[0524] [3] The imaging optical system according to [1] or [2], wherein the following conditional expression is also satisfied:

[0525] 0.5<|far| / f<4.5......(2)

[0526] in

[0527] far represents the focal length of the second air lens, and

[0528] f represents the focal length of the entire system.

[0529] [4] The imaging optical system according to any one of [1] to [3], wherein the following conditional expression is also satisfied:

[0530] 0.1 <faf / far<2.1......(3)

[0531] in

[0532] faf represents the focal length of the first air lens, and

[0533] far represents the focal length of the second air lens.

[0534] [5] The imaging optical system according to any one of [1] to [4], wherein

[0535] The first lens group includes at least one cemented lens, the first lens group is composed of a first split lens group and a second split lens group, wherein the cemented lens on the side closest to the image plane among the at least one cemented lens is set as a boundary, the first split lens group includes the at least one cemented lens, and the second split lens group is arranged on the side closer to the image plane than the cemented lens on the side closest to the image plane among the at least one cemented lens,

[0536] The following conditional expressions are also met:

[0537] 0.1<|f1b / f2|<2.0......(4)

[0538] in

[0539] f1b represents the focal length of the second split lens group, and

[0540] f2 represents the focal length of the second lens group.

[0541] [6] The imaging optical system according to any one of [1] to [5], wherein the following conditional expression is also satisfied:

[0542] 0.1<|f1 / f2|<1.5......(5)

[0543] in

[0544] f1 represents the focal length of the first lens group, and

[0545] f2 represents the focal length of the second lens group.

[0546] [7] The imaging optical system according to any one of [1] to [6], wherein the first negative lens has an aspherical surface.

[0547] [8] The imaging optical system according to any one of [1] to [7], wherein the second negative lens has an aspherical surface.

[0548] [9] An imaging optical system according to any one of [1] to [8], wherein the first lens group includes, in order from the object side to the image side, a first negative lens, a first cemented lens, and at least one first positive lens.

[0549]

[10] An imaging optical system according to any one of [1] to [9], wherein the final lens group includes, from the object side to the image side, a second positive lens, a second cemented lens, and a second negative lens.

[0550]

[11] An imaging optical system according to any one of [1] to

[10] , wherein the second lens group consists of a third negative lens and a third positive lens in order from the object side to the image plane side.

[0551]

[12] The imaging optical system according to any one of [1] to

[11] comprises, in order from the object side to the image side, a first lens group and a second lens group, plus a third lens group as a final lens group having positive refractive power, wherein

[0552] When focusing, the first lens group and the third lens group are both fixed, and the second lens group moves in the optical axis direction.

[0553]

[13] The imaging optical system according to any one of [1] to

[12] , wherein

[0554] The first cemented lens includes a cemented lens in which a negative lens and a positive lens are cemented in this order from the object side to the image plane side, and

[0555] The second cemented lens includes a cemented lens in which a positive lens and a negative lens are cemented in this order from the object side to the image plane side.

[0556]

[14] The imaging optical system according to any one of [1] to

[13] , wherein

[0557] The first cemented lens includes a cemented lens in which a negative lens having a concave surface on the object side and a positive lens having a convex surface on the image plane side are cemented in this order from the object side to the image plane side, and

[0558] The second cemented lens includes a cemented lens in which a positive lens having a convex surface on the object side and a negative lens having a concave surface on the image plane side are cemented in this order from the object side to the image plane side.

[0559]

[15] An imaging device comprising:

[0560] imaging optical system; and

[0561] an imaging element that outputs an imaging signal corresponding to the optical image formed by the imaging optical system,

[0562] The imaging optical system includes, from the object side to the image side,

[0563] a first lens group having positive refractive power,

[0564] a second lens group having negative refractive power, and

[0565] The final lens group has positive refractive power and is arranged on the side closest to the image plane, wherein

[0566] When focusing, the first lens group and the final lens group are both fixed, and the second lens group moves in the optical axis direction,

[0567] The first lens group includes a first negative lens, a first cemented lens in which a negative lens and a positive lens are cemented, and a first air lens having negative refractive power sandwiched between the first negative lens and the first cemented lens, and

[0568] The final lens group includes a second cemented lens in which a positive lens and a negative lens are cemented, a second negative lens, and a second air lens having negative refractive power sandwiched between the second cemented lens and the second negative lens.

[0569]

[16] The imaging optical system according to any one of [1] to

[14] further includes a lens that does not have substantial refractive power.

[0570]

[17] The imaging device according to

[15] , wherein the imaging optical system further includes a lens having no substantial refractive power.

[0571] This application claims priority from Japanese Patent Application No. JP2023-018717 filed with the Japan Patent Office on February 9, 2023, the entire contents of which are incorporated herein by reference.

[0572] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. An imaging optical system comprising, from the object side to the image side, the following components: a first lens group having positive refractive power; a second lens group having negative refractive power; and The final lens group has positive refractive power and is arranged on the side closest to the image plane, wherein When focusing, the first lens group and the final lens group are both fixed, and the second lens group moves in the optical axis direction, The first lens group includes a first negative lens, a first cemented lens in which a negative lens and a positive lens are cemented, and a first air lens having negative refractive power sandwiched between the first negative lens and the first cemented lens, and The final lens group includes a second cemented lens in which a positive lens and a negative lens are cemented, a second negative lens, and a second air lens having negative refractive power sandwiched between the second cemented lens and the second negative lens.

2. The imaging optical system according to claim 1 , further satisfying the following conditional expression: 0.5 < |faf| / f < 2.0 ...... (1) in faf represents the focal length of the first air lens, and f represents the focal length of the entire system.

3. The imaging optical system according to claim 1 , further satisfying the following conditional expression: 0.5 < |far| / f < 4.5 ...... (2) in far represents the focal length of the second air lens, and f represents the focal length of the entire system.

4. The imaging optical system according to claim 1 , wherein the following conditional expression is further satisfied: 0.1 < faf / far < 2.1 ... (3) in faf represents the focal length of the first air lens, and far represents the focal length of the second air lens.

5. The imaging optical system according to claim 1, wherein The first lens group includes at least one cemented lens, the first lens group is composed of a first split lens group and a second split lens group, wherein the cemented lens on the side closest to the image plane among the at least one cemented lens is set as a boundary, the first split lens group includes the at least one cemented lens, and the second split lens group is arranged on the side closer to the image plane than the cemented lens on the side closest to the image plane among the at least one cemented lens, The following conditional expressions are also met: 0.1 < |f1b / f2| < 2.0 ...... (4) in f1b represents the focal length of the second split lens group, and f2 represents the focal length of the second lens group.

6. The imaging optical system according to claim 1 , wherein the following conditional expression is further satisfied: 0.1 < |f1 / f2| < 1.5 ... (5) in f1 represents the focal length of the first lens group, and f2 represents the focal length of the second lens group.

7. The imaging optical system according to claim 1, wherein the first negative lens has an aspherical surface.

8. The imaging optical system according to claim 1, wherein the second negative lens has an aspherical surface.

9. The imaging optical system according to claim 1, wherein the first lens group comprises, in order from the object side to the image side, a first negative lens, a first cemented lens, and at least one first positive lens.

10. The imaging optical system according to claim 1, wherein the final lens group comprises, in order from the object side to the image plane side, a second positive lens, a second cemented lens, and a second negative lens.

11. The imaging optical system according to claim 1, wherein the second lens group consists of a third negative lens and a third positive lens in order from the object side to the image plane side.

12. The imaging optical system according to claim 1, comprising, in order from the object side to the image side, a first lens group and a second lens group, plus a third lens group as a final lens group having positive refractive power, wherein When focusing, the first lens group and the third lens group are both fixed, and the second lens group moves in the optical axis direction.

13. The imaging optical system according to claim 1, wherein The first cemented lens includes a cemented lens in which a negative lens and a positive lens are cemented in this order from the object side to the image plane side, and The second cemented lens includes a cemented lens in which a positive lens and a negative lens are cemented in this order from the object side to the image plane side.

14. The imaging optical system according to claim 1, wherein The first cemented lens includes a cemented lens in which a negative lens having a concave surface on the object side and a positive lens having a convex surface on the image plane side are cemented in this order from the object side to the image plane side, and The second cemented lens includes a cemented lens in which a positive lens having a convex surface on the object side and a negative lens having a concave surface on the image plane side are cemented in this order from the object side to the image plane side.

15. An imaging device comprising: Imaging optical system; and an imaging element that outputs an imaging signal corresponding to the optical image formed by the imaging optical system, The imaging optical system includes, from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, and The final lens group has positive refractive power and is arranged on the side closest to the image plane, wherein When focusing, the first lens group and the final lens group are both fixed, and the second lens group moves in the optical axis direction, The first lens group includes a first negative lens, a first cemented lens in which a negative lens and a positive lens are cemented, and a first air lens having negative refractive power sandwiched between the first negative lens and the first cemented lens, and The final lens group includes a second cemented lens in which a positive lens and a negative lens are cemented, a second negative lens, and a second air lens having negative refractive power sandwiched between the second cemented lens and the second negative lens.

Images