Optical system and image pickup apparatus

Abstract

The invention relates to an optical system and an image pickup apparatus. The optical system includes a first transmissive reflective surface; a second transmissive reflective surface positioned closer to the image than the first transmissive reflective surface; and a lens positioned closer to an object than the first transmissive-reflective surface or closer to an image than the second transmissive-reflective surface. The first transmissive reflective surface is configured to move in an optical axis direction during focusing. The lens is separate from each of the first transmissive reflective surface and the second transmissive reflective surface.

Description

Technical Field

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

[0002] Miniaturization of imaging optical systems has recently been emphasized due to the popularity of smartphone cameras, the shift from single-lens reflex cameras to mirrorless cameras in the high-end camera market, etc. Japanese Patent Laid-Open No. 2005-352273 discloses a compact optical system (polarized light reflective imaging system) including a polarizing element and a half mirror.

[0003] The optical system disclosed in Japanese Patent Laid-Open No. 2005-352273 has a dark F number, for example, 2.85. Due to this configuration, the amount of light from the polarized light reflection imaging system becomes one eighth when random polarized light is incident thereon. Therefore, the system is configured with an F number brighter than that of a conventional optical system. In addition, the optical system disclosed in Japanese Patent Laid-Open No. 2005-352273 cannot satisfactorily suppress aberrations during focusing or increase imaging magnification, and therefore cannot achieve high optical performance in a wide focusing range. Summary of the invention

[0004] An optical system according to one aspect of the present disclosure includes a first transflective surface; a second transflective surface located closer to an image than the first transflective surface; and a lens located closer to an object than the first transflective surface or closer to an image than the second transflective surface. The first transflective surface is configured to move in an optical axis direction during focusing. The lens is separated from each of the first transflective surface and the second transflective surface. An image pickup device having the above optical system also constitutes another aspect of the present disclosure.

[0005] Further features of various embodiments of the present disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic diagram illustrating an optical path of an optical system according to each example.

[0007] Figure 2 is a schematic diagram illustrating another optical path of the optical system according to each example.

[0008] Figure 3 is a cross-sectional view of an optical system according to Example 1.

[0009] Figure 4A and Figure 4B : is an aberration diagram of the optical system according to Example 1.

[0010] Figure 5 is a cross-sectional view of an optical system according to Example 2.

[0011] Fig. 6A and Figure 6B : is an aberration diagram of the optical system according to Example 2.

[0012] Figure 7 is a cross-sectional view of an optical system according to Example 3.

[0013] Fig. 8A and Figure 8B : is an aberration diagram of the optical system according to Example 3.

[0014] Fig. 9 is a cross-sectional view of an optical system according to Example 4.

[0015] Fig. 10A and Fig. 10B : is an aberration diagram of the optical system according to Example 4.

[0016] Fig.11 is a cross-sectional view of an optical system according to Example 5.

[0017] Fig. 12A and Fig. 12B : is an aberration diagram of the optical system according to Example 5.

[0018] Fig.13 is a cross-sectional view of an optical system according to Example 6.

[0019] Fig.14A and Fig. 14B : is an aberration diagram of the optical system according to Example 6.

[0020] Fig.15 is a cross-sectional view of an optical system according to Example 7.

[0021] Fig.16A and Fig. 16B : is an aberration diagram of the optical system according to Example 7.

[0022] Fig.17 is a cross-sectional view of an optical system according to Example 8.

[0023] Fig.18A and Fig.18B : is an aberration diagram of the optical system according to Example 8.

[0024] Fig.19 is a cross-sectional view of an optical system according to Example 9.

[0025] Fig. 20A and Fig. 20B : is an aberration diagram of the optical system according to Example 9.

[0026] Fig.21 is a cross-sectional view of an optical system according to Example 10.

[0027] Fig.22A and Fig. 22B : is an aberration diagram of the optical system according to Example 10.

[0028] Fig.23 is a cross-sectional view of an optical system according to Example 11.

[0029] Fig.24A and Fig. 24B : is an aberration diagram of the optical system according to Example 11.

[0030] Fig.25 is a cross-sectional view of an optical system according to Example 12.

[0031] Fig.26A and Fig.26B : is an aberration diagram of the optical system according to Example 12.

[0032] Fig. 27 is a cross-sectional view of an optical system according to Example 13.

[0033] Fig.28A and Fig.28B : is an aberration diagram of the optical system according to Example 13.

[0034] Fig.29 is a cross-sectional view of an optical system according to Example 14.

[0035] Fig. 30A and Fig. 30B : is an aberration diagram of the optical system according to Example 14.

[0036] Fig.31 is a cross-sectional view of the optical system according to Example 15.

[0037] Fig.32A and Fig.32B : is an aberration diagram of the optical system according to Example 15.

[0038] Fig.33 is a cross-sectional view of the optical system according to Example 16.

[0039] Fig.34A and Fig.34B : is an aberration diagram of the optical system according to Example 16.

[0040] Fig.35 is a cross-sectional view of the optical system according to Example 17.

[0041] Fig.36A and Fig.36B : is an aberration diagram of the optical system according to Example 17.

[0042] Fig.37 is a cross-sectional view of the optical system according to Example 18.

[0043] Fig.38A and Fig.38B : is an aberration diagram of the optical system according to Example 18.

[0044] Fig.39 is a cross-sectional view of the optical system according to Example 19.

[0045] Fig.40A and Fig.40B 2 is an aberration diagram of the optical system according to Example 19.

[0046] Fig.41 is a cross-sectional view of an optical system according to Example 20.

[0047] Fig.42A and Fig.42B 2 is an aberration diagram of the optical system according to Example 20.

[0048] Fig.43 is a cross-sectional view of the optical system according to Example 21.

[0049] Fig.44A and Fig.44B 21 are aberration diagrams of the optical system according to Example 21.

[0050] Fig.45 is a cross-sectional view of the optical system according to Example 22.

[0051] Fig.46A and Fig.46B 2 is an aberration diagram of the optical system according to Example 22.

[0052] Fig.47 is a cross-sectional view of the optical system according to Example 23.

[0053] Fig.48A and Fig.48B 2 is an aberration diagram of the optical system according to Example 23.

[0054] Fig.49 is a cross-sectional view of the optical system according to Example 24.

[0055] Fig.50A and Fig.50B 2 is an aberration diagram of the optical system according to Example 24.

[0056] Fig.51 is a cross-sectional view of the optical system according to Example 25.

[0057] Fig.52A and Fig.52B 2 is an aberration diagram of the optical system according to Example 25.

[0058] Fig.53 is a cross-sectional view of the optical system according to Example 26.

[0059] Fig.54A and Fig.54B 2 is an aberration diagram of the optical system according to Example 26.

[0060] Fig.55 is a schematic diagram of an image pickup device having an optical system according to any one of the above-described examples. DETAILED DESCRIPTION

[0061] Referring now to the drawings, a detailed description will be given of embodiments according to the present disclosure.

[0062] The optical system (imaging optical system) according to each example performs imaging by forming an object image on an image plane, by disposing an image sensor, a photosensitive film, etc. on the image plane, and by capturing an image. The optical system according to each example includes a first refractive lens L1, a first transmissive reflection (e.g., semi-transmissive reflection) surface HM1, a quarter wave plate QWP, and a second transmissive reflection surface HM2 in sequence from the object side to the image side. Light incident from the object side sequentially passes through the first transmissive reflection surface HM1 and the quarter wave plate QWP, and is reflected by the second transmissive reflection surface HM2. The light then passes through the quarter wave plate QWP, is reflected on the first transmissive reflection surface HM1, passes through the quarter wave plate QWP and the second transmissive reflection surface HM2, and enters an image plane IM such as an image sensor or a photosensitive film. Therefore, a phase shifter may be disposed between the first transmissive reflection surface HM1 and the second transmissive reflection surface HM2. The phase shifter may use, for example, a quarter wave plate (QWP) or a 45° optical rotator (such as a Faraday rotator).

[0063] The first transflective surfaces HM1 and HM2 do not necessarily have a transmittance of 50% and a reflectance of 50%. The ratio of transmittance to reflectance for randomly polarized light may be in the range of 1:3 to 3:1. Randomly polarized light is light with Stokes parameters S0=1, S1=S2=S3=0. Each of the first transflective surface HM1 and the second transflective surface HM2 may absorb light. A lens (a light-transmitting member made of glass or resin) may be formed or bonded on both sides or one side of the first transflective surface HM1 or the second transflective surface HM2. In other words, at least one of the first transflective surface and the second transflective surface may be provided on the bonding surface of the two light-transmitting members.

[0064] The quarter wave plate QWP can use, for example, a crystal, a polymer film, or a liquid crystal alignment layer having birefringence. A laminate of such crystals, polymer films, or liquid crystal alignment layers can also be used. Proper lamination of them can provide a phase difference close to one-quarter of the wavelength in a wide wavelength range. For example, "WA-140T" of Nippon Kayaku Co., Ltd., "Polar Correct" of Colorlink Japan Co., Ltd., etc. can be used. The quarter wave plate QWP is not limited to the above examples, and may be a quarter wave plate QWP using a subwavelength structure or a metastructure. More specifically, for example, an inorganic wave plate of Dexerials or a product named "Nanoable Waveplate" of ENEOS can be used.

[0065] The quarter wave plate QWP may be bonded to the first transmissive reflective surface HM1 or the second transmissive reflective surface HM2, for example. The quarter wave plate QWP may also be disposed separately from these transmissive reflective surfaces. For example, a film as a quarter wave plate QWP may be directly inserted into the optical path, or the film may be bonded to a glass plate and inserted into the optical path. Lenses may be formed or bonded on both sides or one side of the quarter wave plate QWP. For example, a lens may be molded on one side or both sides of an inorganic wave plate as a substrate using wafer-level optical technology.

[0066] In the case where an optical system with such a configuration is extended as a whole during focusing (i.e., focusing is performed by moving all lenses forward and backward by the same amount along the optical axis), image quality deteriorates during extension. Generally, the expected focusing range of an imaging lens is from infinity to a distance greater than 0.1 times, and focusing can be performed and high image quality can be ensured at least in this range. Focusing up to high magnifications can be performed. In each example, changing the focus position is referred to as focusing. Unless otherwise specified, the direction in which optical elements such as lenses and transmissive reflective surfaces are moved during focusing is along the optical axis, and descriptions such as "in a direction along the optical axis" can be omitted. In general, as the optical system has a larger aperture diameter, it becomes more difficult to maintain high image quality over a wide imaging magnification range. The optical system according to each example achieves high image quality over a wide imaging magnification range despite their large apertures.

[0067] The optical system according to each example is an imaging optical system in which the focus position can be changed by moving the first transmissive reflective surface HM1 forward and backward along the optical axis. The optical system according to each example includes a refractive lens that does not move when the focus position is changed, or the distance between the refractive lens and the first transmissive reflective surface HM1 changes and the refractive lens is not integrated with any of the first transmissive reflective surface HM1 and the second transmissive reflective surface HM2 (for example, the refractive lens is separated from each transmissive reflective surface). The refractive lens used in this article does not include optical elements that are parallel plates or almost parallel plates, such as protective filters, sensor protective glass, IR cut-off filters, UV cut-off filters, and low-pass filters. An example of a refractive lens that is not an almost parallel plate is, for example, a spherical lens, in which the absolute value of the radius of curvature of at least one surface is less than 1 / 20 of the total focal length of the optical system. In addition, "integrated" here means that the lens is bonded, paired or fixed (for example, it does not matter if another lens is involved), and "non-integrated" means that an air gap is involved (for example, between them).

[0068] Therefore, independently moving the first transflective surface HM1 during focusing can provide high image quality in a wide focusing range. Moving a reflective surface with high aberration correction capability can provide high image quality in a wide focusing range. As in each numerical example described later, the first transflective surface HM1 can have a flat surface. In this case, even if the first transflective surface HM1 moves with focusing and the second transflective surface HM2 is fixed, high image quality can be achieved. This is for the following reasons. For example, as the first transflective surface HM1 moves forward, the distance between the first transflective surface HM1 and the second transflective surface HM2 increases. This is equivalent to extending the optical path length from the point where the light beam is reflected by the second transflective surface HM2 to the image plane, and moving the second transflective surface HM2 with high aberration correction capability in a pseudo manner. Therefore, even if the first transflective surface HM1 does not have the capability, the second transflective surface HM2 can be moved in a pseudo manner by moving the first transflective surface HM1, and high image quality can be achieved in a wide focusing range.

[0069] In order to move the optical element for focusing, space is required to accommodate the movement. The first transflective surface HM1 is suitable as a unit to be moved during focusing because it is easy to ensure this space on the object side. If the second transflective surface HM2 is moved for focusing, it is difficult to ensure this space. As in each numerical example described later, the second transflective surface HM2 may have a shape concave toward the object side or may be flat. In order to focus from infinity to close distance, the second transflective surface HM2 often needs to be moved toward the image side. In the case where a longer back focal length is required, such as in a lens for a lens-interchangeable type camera, an unusable space is provided on the image side of the second transflective surface HM2. Even if the back focal length can be reduced, it is difficult to ensure enough space for focusing. This is because a refractive lens is placed on the image side of the second transflective surface HM2 to correct image plane fluctuations or increase light converging power and increase Fno.

[0070] In the optical system according to each example, the following inequality (1) can be satisfied:

[0071]

[0072] in is the refractive power of the portion of the optical system on the object side of the first transflective surface HM1, and It is the power of the (entire) optical system.

[0073] In the optical system according to each example, the reflective surface has the highest aberration correction capability. The reflective surface has a Petzval sum with a sign opposite to the refractive power of the reflective surface, and does not generate chromatic aberration. The manner in which this reflective surface is effectively utilized is important in achieving high image quality in a wide focusing range despite a large aperture.

[0074] Satisfying inequality (1) can make the light beam enter the reflective surface with a high light height and leave the reflective surface at an angle close to the normal of the reflective surface (generally, as the incident angle relative to the surface normal increases, the aberration of the light increases). Therefore, high image quality can be achieved in a wide focusing range. In the case where the value becomes higher than the upper limit of inequality (1), the light is largely converged on the front side (object side) of the first transmissive reflective surface HM1, and the incident light height on the reflective surface decreases. Therefore, the contribution of the reflective surface to aberration correction becomes smaller, and it is difficult to achieve high image quality in a wide focusing range. On the other hand, in the case where the value becomes lower than the lower limit of inequality (1), the effective diameter of the reflective surface increases, the size of the entire optical system increases, and the weight of the lens unit (focusing unit) moved during focusing increases. In addition, the optical system as a whole tends to have an increase characteristic of the reverse telephoto type, so the total optical length increases. In the case where the weight of the focusing unit increases, a large high-thrust motor is used during automatic focusing (AF), which increases the size and manufacturing cost. The refractive power on the object side of the first transflective surface HM1 is, for example, the refractive power of a subgroup from the first surface to the third surface in Numerical Example 1 described later.

[0075] In the optical system according to each example, the following inequality (2) can be satisfied:

[0076] 0.15≤Hm2 / f≤3.00 (2)

[0077] Wherein Hm2 is the distance from the optical axis to the reflection point in a direction perpendicular to the optical axis when the on-axis marginal ray is reflected by the second transflective surface HM2, and f is the focal length of the (entire) optical system.

[0078] In the case where the value becomes higher than the upper limit of inequality (2), the transflective surface becomes too large for the specifications of the optical system, and the size of the entire optical system increases. In addition, in the optical system according to each example, the transflective surface with a reflective force tends to have a high tilt sensitivity to aberrations. Therefore, the transflective surface with a reflective force can have a tilt adjustment mechanism, and in the case where this mechanism is incorporated, the diameter of the optical system including the lens barrel becomes even larger. On the other hand, in the case where the value becomes lower than the lower limit of inequality (2), the incident light height on the reflective surface becomes too low, and the longitudinal chromatic aberration cannot be fully corrected. As the aperture diameter increases, the influence of the longitudinal chromatic aberration on the image quality increases, so in a lens with a large aperture diameter such as the optical system according to the example, the longitudinal chromatic aberration can be particularly small.

[0079] In the optical system according to each example, the following inequality (3) can be satisfied:

[0080] 0.0≤dpupil / f≤2.0 (3)

[0081] where dpupil is the distance from the surface closest to the object to the entrance pupil of the optical system.

[0082] Here, the entrance pupil is the entrance pupil for the on-axis light beam, which is the entrance pupil at the maximum aperture in an optical system having an aperture stop. In the case where the value becomes higher than the upper limit of inequality (3), the shielding of the off-axis light beam by the periphery of the lens barrel and the lens and thus the peripheral dimming increase. In order to prevent light shielding, the lens diameter on the object side is increased, so the size of the entire optical system increases. By definition, in a general optical system, the value never becomes lower than the lower limit of inequality (3).

[0083] In the optical system according to each example, the following inequality (4) can be satisfied:

[0084] 0.6≤Pm1 / Ppupil≤2.0 (4)

[0085] Wherein Pm1 is the effective diameter of the first transflective surface HM1, and Ppupil is the entrance pupil diameter of the optical system.

[0086] Here, the entrance pupil is the entrance pupil for the on-axis light beam. The effective diameter of the first transflective surface HM1 is the larger of the diameter of the area through which the normal light beam passes and the diameter of the area through which it is reflected in the first transflective surface HM1. In the case where the value becomes higher than the upper limit of the inequality (4), the effective diameter of the first transflective surface HM1 is large relative to the entrance pupil diameter, and the weight of the focusing unit increases. On the other hand, in the case where the value becomes lower than the lower limit of the inequality (4), the effective diameter of the first transflective surface HM1 relative to the entrance pupil decreases, and the shielding of the off-axis light beam and thus the peripheral dimming increase. In addition, the first transflective surface HM1 and the second transflective surface HM2 cannot fully correct the aberration, and the image quality cannot be improved.

[0087] In the optical system according to each example, the following inequality (5) can be satisfied:

[0088] 0.5≤Fno≤2.5 (5)

[0089] Where Fno is the F number of the optical system.

[0090] In the case where the value becomes higher than the upper limit of inequality (5), together with the loss of light caused by each transflective surface, the amount of light reaching the image plane becomes too small. In addition, the polarizer (polarizing plate) and polarization selective transflective element described later generally cannot completely absorb or reflect light in the absorption axis or reflection axis direction, respectively. Therefore, the light of the characteristic error, for example, directly reaches the image plane without being reflected by any of the two transflective surfaces, and becomes ghost light. Since the intensity of this ghost light does not depend on the F number, the ghost light intensity decreases relatively as the F number becomes brighter. Therefore, from the viewpoint of reducing the ghost light intensity, the value can be within the range of inequality (5). In addition, in the general case where the medium on the image side is air, the value never becomes lower than the lower limit of inequality (5).

[0091] Assume that the optical system according to each example includes a refractive lens disposed on the object side of the first transflective surface HM1, configured to move integrally with the first transflective surface HM1 during focusing, and having an air gap between it and the first transflective surface HM1. Then, the following inequality (6) can be satisfied:

[0092]

[0093] in is the refractive power of a portion of the optical system on the object side of the lens unit that moves integrally with the first transflective surface HM1 during focusing.

[0094] During focusing, a light beam that is generally as close to a parallel light beam as possible can enter the focusing unit, and by doing so, high image quality can be achieved within a wide focusing range. In the case where the value becomes higher than the upper limit of inequality (6), light with a strong tendency to converge enters the focusing unit, and this is not suitable for the above reasons. In addition, unless the focusing unit has a strong negative power, the back focus is reduced. Therefore, this is not suitable for applications requiring a relatively long back focus, such as applications for lens interchangeable type camera systems. In addition, the light is largely converged on the front side of the first transmissive reflective surface HM1, and the incident light height on the reflective surface is reduced. Therefore, the contribution of the reflective surface to aberration correction is reduced, and it becomes difficult to achieve high image quality within a wide focusing range. On the other hand, in the case where the value becomes lower than the lower limit of inequality (6), the effective diameter of the reflective surface and ultimately the size of the entire optical system increase, and the weight of the lens unit (e.g., focusing unit) that is moved during focusing increases. In addition, the total optical system tends to have an increase characteristic of the reverse telephoto type, so the total optical length increases.

[0095] In the optical system according to each example, the following inequality (7) can be satisfied:

[0096] 0.005≤|Δdf| / f / Fno≤1.000 (7)

[0097] where |Δdf| is the amount of movement (during focusing) when the focus position changes from infinity to a distance corresponding to 10 times the focal length of the (entire) optical system.

[0098] In the case where the value becomes higher than the upper limit of inequality (7), the amount of movement for focusing increases. The amount of movement (or extension) of the focusing unit increases, and the optical system becomes larger during the movement (extension). Alternatively, the amount of movement of the focusing unit becomes too large, and the AF time becomes longer. On the other hand, in the case where the value becomes lower than the lower limit of inequality (7), the focusing amount becomes too small for the depth of field, and fine focusing becomes difficult.

[0099] In the optical system according to each example, the distance (pitch) between the first transflective surface HM1 and the second transflective surface HM2 can be changed during focusing. Since normal light passes through the area between the reflective surfaces three times in total, by making this pitch variable, high image quality can be achieved in a wide focusing range while suppressing the amount of movement of the optical element accompanying focusing.

[0100] In the optical system according to each example, when changing the focus position (during focusing), the aperture stop SP can be moved integrally with the first transmissive reflective surface HM1. Therefore, the aperture stop SP or the entrance pupil is moved toward the object side accompanying focusing, so that the one-sided aperture focusing from infinity to a close distance can be suppressed. The one-sided aperture is a phenomenon in which the center of the off-axis light beam passes through a position away from the center of the aperture stop when the off-axis light beam passes through the aperture stop. In the case where the distance between the centers is small, this is not a big problem, but in the case where the distance is large, when the aperture becomes narrow, problems such as peripheral dimming or uneven blur shape occur.

[0101] In the optical system according to each example, the refractive lens disposed outside the area between the first transflective surface HM1 and the second transflective surface HM2 can be moved along with focusing. That is, at least one of the refractive lens on the object side of the first transflective surface HM1 and the refractive lens on the image side of the second transflective surface HM2 can be moved as a focusing unit (or floating unit). The lens between the two transflective surfaces acts on the light beam three times, so it has a strong influence on aberration correction, but fine adjustment of the aberration correction effect is difficult. The refractive lens configured to act on the light beam only once to moderately affect the aberration and disposed outside the transflective surface can be moved as a focusing unit (or floating unit).

[0102] In the optical system according to each example, each of the first transflective surface HM1 and the second transflective surface HM2 may not rotate about the optical axis by 0.5° or more when changing the focus position. As described later, in the optical system according to each example, the relative angle of the quarter wave plate QWP and each transflective surface with the optical axis as the rotation axis is important for suppressing ghosting and ensuring the light amount of normal light. Therefore, the rotational movement of each of the first transflective surface HM1 and the second transflective surface HM2 around the optical axis during focusing can be sufficiently small. In the case where all anisotropic elements such as the quarter wave plate QWP and each transflective surface are rotated by the same amount, there is no problem in suppressing ghosting and ensuring the light amount of normal light. However, in the case where the polarization degree of light incident on the optical system is not low, the direction of the transmitted light changes due to the equal rotation of each element. Therefore, depending on the object, brightness changes and color changes may occur with focusing.

[0103] In the optical system according to each example, the following inequality (8) can be satisfied:

[0104] 0.0≤|θm|≤8.0 (8)

[0105] Here, θm (°) may be the smaller of the opening angle of the first transflective surface HM1 and the opening angle of the second transflective surface HM2.

[0106] Here, the opening angle is the angle of the surface normal relative to the direction perpendicular to the optical axis, and is evaluated as the maximum value within the effective surface. The effective surface is the area through which normal light (ie, non-ghost or non-stray light) passes.

[0107] As described later, in the optical system according to each example, one of the first transmissive reflective surface HM1 and the second transmissive reflective surface HM2 can use a polarization selective transmissive reflective element such as a polarization beam splitter (PBS), and the other can use a half mirror. The half mirror can be formed by depositing a metal or dielectric multilayer film on glass or resin using vapor deposition or sputtering, so it can support a relatively wide range of opening angles. On the other hand, it is difficult to form a polarization selective transmissive reflective element on a curved surface. In the case where the shape is close to a flat surface, it can be manufactured using a process similar to that of a flat surface, but as the surface deviates from a flat surface, a special process is used. Therefore, in the case where the value becomes higher than the upper limit of inequality (8), it is difficult to form a polarization selective transmissive reflective element. By definition, the value never becomes lower than the lower limit of inequality (8).

[0108] In the case where a flexible material such as a resin film or a wire grid with a resin film as a substrate is used as a polarization-selective transflective element, the surface accuracy of the transflective surface must be appropriately maintained. Therefore, in the case where one of the first transflective surface HM1 and the second transflective surface HM2 is made of such a material, it can be bonded to glass or a hard resin with a glass transition temperature of 40°C or higher. The two surfaces can be bonded to glass or a hard resin with a glass transition temperature of 40°C or higher. The adhesive used for bonding (for example, including an elastic adhesive) is not specifically specified here, but the adhesive layer can be 25μm or less, or 15μm or less. In the case where only one surface is bonded, the holder may not directly contact the transflective surface when holding the lens. For example, it can be held at the bonded glass or hard resin portion. This configuration can reduce the surface distortion of the transflective surface.

[0109] Regarding the surface accuracy, the roughness of the reflected wavefront can be sufficiently smooth, and the rms of the component of 1 / mm or more on the reflected wavefront can be 10nm or less, and the rms of the component of 0.05 / mm or more and 1 / mm or less can be 10nm or less. This configuration can sufficiently suppress the degradation of image quality caused by the poor surface accuracy of the reflective surface.

[0110] In each example, at least one of the first transflective surface HM1 and the second transflective surface HM2 may be a spherical surface. Using an aspherical surface is beneficial for aberration correction, but it is more difficult to make the surface shape closer to the design value than a spherical surface. Therefore, if it uses a spherical surface, manufacturing becomes easier. In addition, subtle processing traces tend to remain on the aspherical surface, and in the case where such processing traces are particularly left on the reflective surface, the pattern generated by the processing traces is likely to be reflected in the image degradation (bokeh). In a lens with a large aperture diameter for image and video applications, users also emphasize the quality of image degradation, so such a pattern does not appear.

[0111] The optical system according to each example may include an image stabilization unit. The image stabilization unit is a unit that provides a blur prevention function to the optical system, such as camera shake caused by moving the camera by a recognizable or appropriate amount (e.g., according to the detected blur amount) in a direction perpendicular to the optical axis during imaging. The image stabilization unit may be placed on the object side of the first transflective surface. In this way, the image stabilization unit may be incorporated without increasing the total length of the optical system. Because the aberration during the image stabilization operation becomes large, the transflective surface may not be used as an image stabilization unit.

[0112] In the case where the optical system according to each example has an image stabilization unit, the following inequality (9) can be satisfied:

[0113] 0.6≤β≤1.5 (9)

[0114] Wherein β is the lateral magnification of the lens unit on the image side of the second transflective surface HM2.

[0115] When the value becomes higher than the upper limit of the inequality (9), the number of lens units on the image side of the second transmissive reflective surface HM2 increases, and the total length or aberration of the lens units on the image side of the second transmissive reflective surface HM2 increases. On the other hand, when the value becomes lower than the lower limit of the inequality (9), the amount of movement of the image stabilization unit in the direction perpendicular to the optical axis becomes too large for a sufficient image stabilization effect, and it becomes difficult to configure a drive mechanism that performs image stabilization.

[0116] The optical system according to each example may be a coaxial system. This configuration improves the ease of manufacturing each component and facilitates the assembly process. However, the effective diameter and outer diameter of the lens and the transmissive reflective surface do not need to be rotationally symmetrical, and, for example, a rectangular shape may be used.

[0117] The optical system according to each example may be a primary imaging system, and in the case where the optical system is a secondary or higher order imaging system, light that has been imaged once is to be imaged again, and the total length increases.

[0118] In the case where the optical system according to each example has an AF function and has a large aperture diameter with an F number of 1.4 or less, high stop accuracy of the focusing unit is required. Therefore, for example, mechanical stops are provided at two points at infinity and close distance, and the focusing unit is moved so as to be pressed against the stops, and AF can be performed with high stop accuracy at least for infinity and close distance.

[0119] Inequalities (1) to (9) can be replaced by the following inequalities (1a) to (9a):

[0120]

[0121] 0.165≤Hm2 / f≤2.000 (2a)

[0122] 0.00≤dpupil / f≤1.75 (3a)

[0123] 0.7≤Pm1 / Ppupil≤1.9 (4a)

[0124] 0.5≤Fno≤2.4 (5a)

[0125]

[0126] 0.010≤|△df| / f / Fno≤0.900 (7a)

[0127] 0.0≤|θm|≤6.0 (8a)

[0128] 0.6≤β≤1.2 (9a)

[0129] Inequalities (1) to (9) can be replaced by the following inequalities (1b) to (9b):

[0130]

[0131] 0.18≤Hm2 / f≤1.00 (2b)

[0132] 0.0≤dpupil / f≤1.4 (3b)

[0133] 0.75≤Pml / Ppupil≤1.85 (4b)

[0134] 0.52≤Fno≤2.20 (5b)

[0135]

[0136] 0.015≤|△df| / f / Fno≤0.800 (7b)

[0137] 0.0≤|θm|≤5.0 (8b)

[0138] 0.6≤β≤1.() (9b)

[0139] As described later, in the optical system according to each example, a polarization selective transflective element may be used as one of the first transflective surface HM1 and the second transflective surface HM2. Examples of polarization selective transflective elements include "WGF" manufactured by Asahi Kasei, "IQP-E" manufactured by 3M, and "ProFlux" manufactured by Moxtek, Inc. The transmittance of the reflection axis of the polarization selective transflective element may be about 1% or less, or 0.5% or less, or 0.25% or less on average in the wavelength range of use. Therefore, stray light that reaches the image plane without being reflected once by the reflection surface (which will be referred to as "single path ghosting") can be effectively suppressed. However, even if the polarization selective transflective element has a high transmittance of the reflection axis, single path ghosting can be suppressed by using it in combination with a linear polarizer. A half mirror or a cholesteric liquid crystal may be used as another transflective surface. In the case of using a half mirror, the light amount of randomly polarized light incident from the object side becomes 12.5% ​​or less until the light reaches the image plane. By using cholesteric liquid crystal, the amount of light on the image plane can be approximately doubled compared to the case of using a half mirror.

[0140] The optical system according to each example having the following configuration, for example, can suppress a decrease in the amount of light in a normal imaging optical path while reducing ghost light (unnecessary light leakage) that passes through a transflective surface from the optical path without being reflected even once.

[0141] The optical system according to each example may use, as a polarization selective reflection element, an optical element created by forming a grid on a lens reflection surface during lens molding and then by evaporating, printing, or photolithography a metal or dielectric material.

[0142] Configuration 1 using polarization

[0143] Reference now Figure 1 , a description will be given of a configuration utilizing polarization. Figure 1 is a schematic diagram illustrating an optical path of an optical system according to this example. The optical system according to this example includes two transmissive reflective surfaces. Here, the transmissive reflective surface disposed on the object side of the optical system according to this configuration includes a polarization-selective transmissive reflective element (polarization beam splitter: PBS): A. The transmissive reflective surface disposed on the image plane side of the imaging optical system according to this example includes a half mirror (HM): C. A first quarter wave plate (QWP1): B is disposed between the polarization-selective transmissive reflective element PBS and the half mirror HM. A second quarter wave plate (QWP2): D and a linear polarizer (POL): E are disposed between the half mirror HM and the image plane IM. Here, the polarization-selective transmissive reflective element A is an element configured to reflect linearly polarized light polarized in the same direction as when it has passed through the linear polarizer E and transmit linearly polarized light perpendicular to this direction.

[0144] The polarization selective transflective element is, for example, a wire grid polarizer or a reflective type polarizer having a laminated retardation film configuration. At this time, the wire grid forming surface or the retardation film surface of the polarization selective transflective element A serves as a transflective surface. The wire grid polarizer does not necessarily have to be made of aligned metal wires, but may be anything including thin metal or dielectric layers arranged at predetermined intervals, as long as it can be used as a polarization selective transflective element. For example, an element having a metal or dielectric layer aligned by vapor deposition may be used.

[0145] The first quarter wave plate B and the second quarter wave plate D are arranged with their slow axes tilted 45° relative to the polarization transmission axis of the linear polarizer E. Here, the first quarter wave plate B and the second quarter wave plate D can be arranged with their slow axes tilted 90°. Due to this arrangement, in the case where light passes through the first quarter wave plate B and the second quarter wave plate D, the wavelength dispersion characteristics of the wave plates are offset. The half mirror C is, for example, a half mirror formed by a dielectric multilayer film or metal deposition, and the half mirror C serves as a transmissive reflective surface. The linear polarizer E is, for example, an absorption type linear polarizer.

[0146] A description will now be given of the optical path selection and function in the configuration utilizing polarization. Light incident on the optical system from the object side becomes linearly polarized light by the polarization selective transmissive reflective element A, becomes circularly polarized light by the first quarter wave plate B, and enters the half mirror C. A portion of the light reaching the half mirror C is reflected, becomes circularly polarized in the opposite direction, and returns to the first quarter wave plate B.

[0147] The reverse circularly polarized light that has returned to the first quarter wave plate B returns to the polarization selective transflective element A through the first quarter wave plate B as linearly polarized light polarized in a direction orthogonal to the direction when the light first passed through the polarization selective transflective element A, and is reflected by the polarization selective transflective element A. Here, due to the polarization selectivity of the polarization selective transflective element A, the linearly polarized light polarized in a direction perpendicular to the direction when the light first passed through the polarization selective transflective element A is reflected.

[0148] Part of the light that has reached the half mirror C is transmitted through it, passes through the second quarter wave plate D and becomes linearly polarized light polarized in the same direction as the direction when the light passes through the polarization selective transflective element A, enters the linear polarizer E, and is absorbed by the linear polarizer E.

[0149] The light reflected by the polarization selective transflective element A becomes circularly polarized by the first quarter wave plate B and enters the half mirror C. A portion of the light that has reached the half mirror C transmits through it and enters the second quarter wave plate D. Due to the second quarter wave plate D, the incident light becomes linearly polarized light polarized in a direction parallel to the direction of the linearly polarized light reflected by the polarization selective transflective element A. The light transmitted through the second quarter wave plate D enters the linear polarizer E. Here, the polarization of the light and the transmission axis of the linear polarizer E match, so most of the light is transmitted and guided to the image plane IM.

[0150] Due to the above-mentioned action, only the light that transmits the polarization selective transflective element PBS, is reflected by the half mirror C, is reflected by the polarization selective transflective element PBS, and transmits the half mirror C is guided to the image plane IM. In the case of using cholesteric liquid crystal instead of the half mirror C, the cholesteric liquid crystal can be installed so that the circular polarized light in the direction of the incident light is largely reflected during the first reflection of the cholesteric liquid crystal. Therefore, the amount of light on the normal optical path can be increased while reducing the ghost light.

[0151] Image sensors and charge coupled devices (CCDs) that can be used for image plane IM generally have high surface reflectivity. In this configuration, the light reflected on image plane IM passes through the linear polarizer E again and is converted into circular polarized light by the second quarter wave plate D. The light emitted from the second quarter wave plate D is then reflected on the half mirror C, becomes circular polarized light in the opposite direction, and passes through the second quarter wave plate D again. At this time, the circular polarized light is converted by the second quarter wave plate D into linear polarized light polarized in a direction perpendicular to the direction of the light that has just passed through the linear polarizer E. Since the direction of this linear polarized light is orthogonal to the transmission axis of the linear polarizer E, most of the light is absorbed by the linear polarizer E. Therefore, in this configuration, most of the light reflected on the image plane IM, the half mirror C, and the image plane IM in turn is cut off, and the ghosting and glare associated with the image plane IM are not very obvious. In order to obtain such a reflection reduction effect, an optical low-pass filter using birefringence may not be placed between the image plane IM and the linear polarizer E. This is because the optical low-pass filter causes the polarization state to deviate from the desired polarization state.

[0152] In this configuration, a third quarter wave plate (not shown) may be disposed immediately after the linear polarizer E (e.g., next to the linear polarizer E and on the image side of the linear polarizer E). In this case, the angle between the absorption axis of the linear polarizer E and the slow axis of the third quarter wave plate may be 45° or 135° (when viewed from the optical axis direction). This configuration may also suppress light reflected by the image plane IM and reflection from the lens surface between the third quarter wave plate and the image plane IM.

[0153] Furthermore, in this configuration, a linear polarizer (not shown) may be disposed between the polarization selective transmission reflective element A and the object. At this time, the polarization selective transmission reflective element A and the linear polarizer are placed so that their transmission axes coincide with each other. This configuration can reduce ghosting caused by light that has been reflected by the polarization selective transmission reflective element A and reflected by the lens surface between the polarization selective transmission reflective element A and the object. Furthermore, this configuration can largely absorb polarized light in the reflection axis direction of the polarization selective transmission reflective element A and significantly reduce single-path ghosting. Furthermore, absorbing ultraviolet rays and the like can improve the environmental resistance of the polarization selective transmission reflective element A.

[0154] In this configuration, a quarter wave plate can be placed between the polarization selective transflective element A and the object (in the case of deploying the above-mentioned linear polarizer, it is deployed between the linear polarizer and the object). At this time, the quarter wave plate and the polarization selective transflective element A are arranged so that the fast axis or slow axis of the quarter wave plate forms an angle of 45° with the transmission axis of the polarization selective transflective element A. Therefore, even if the light incident from the object side is linearly polarized, pseudo depolarization is performed, and imaging can be performed regardless of its polarization direction. A depolarizing element can be placed instead of a quarter wave plate. For example, the product name "Cosmoshine SRF" of Toyobo Co., Ltd. can be used as a depolarizing element. Cosmoshine SRF is a film with a large birefringence of about 10000nm, and compared with the case of using a quarter wave plate, this film can prevent color unevenness caused by the wavelength characteristics and angle characteristics of the wave plate.

[0155] Configuration 2 using polarization

[0156] Reference now Figure 2 , a description will be given of a configuration utilizing polarization. Figure 2 is a schematic diagram of an optical path of an optical system according to each example. The optical system according to each example includes two transmissive reflective surfaces. Here, the transmissive reflective surface placed on the object side of the optical system according to each example includes a half mirror (HM): C. The transmissive reflective surface disposed on the display element side of the optical system according to each example includes a polarization selective transmissive reflective element (PBS): A. The first quarter wave plate (QWP1): B is disposed between the polarization selective transmissive reflective element PBS and the half mirror HM. A linear polarizer (POL): E and a second quarter wave plate (QWP2): D are disposed between the half mirror HM and the object plane. The configuration of each polarization element and the appropriate arrangement of the optical axis orientation are similar to those of configuration 1 utilizing polarization.

[0157] A description will now be given of the optical path selection and action in the configuration utilizing polarization. Light incident on the optical system from the object side becomes linearly polarized light by the linear polarizer E, becomes circularly polarized light by the second quarter wave plate D, and enters the half mirror C. A portion of the light that has reached the half mirror C is reflected, becomes circularly polarized light in the opposite direction, and returns to the second quarter wave plate D.

[0158] The light reaching the half mirror C and reflected by the half mirror C becomes circularly polarized light in the direction opposite to the incident direction. This light is converted by the second quarter wave plate D into linearly polarized light polarized in a direction perpendicular to the direction when it passes through the linear polarizer E, enters the linear polarizer E, and is absorbed by the linear polarizer E.

[0159] The light having passed through the half mirror C is converted by the first quarter wave plate B into linearly polarized light polarized in the same direction as that of the light just passed through the linear polarizer E. This linearly polarized light is reflected by the polarization selective transflective element A and returns to the first quarter wave plate B. The light is then converted into circularly polarized light by the first quarter wave plate B, and a portion of it is reflected by the half mirror C. The light reflected by the half mirror C enters the first quarter wave plate B again and is converted into linearly polarized light having a polarization direction perpendicular to that when it was reflected by the polarization selective transflective element A. This linearly polarized light passes through the polarization selective transflective element A and is guided to the image plane IM.

[0160] Due to the above-described action, only light that transmits the half mirror C, is reflected on the polarization selective transflective element PBS, is reflected on the half mirror C, and transmits the polarization selective transflective element PBS is guided to the image plane IM.

[0161] Due to this arrangement, a linear polarizer A' can be placed between the polarization selective transflective element A and the image plane IM. In this case, the transmission axes of the linear polarizer A' and the polarization selective transflective element A are matched. This configuration can absorb light that is reflected on the image plane IM, reflected on the polarization selective transflective element A, enters the image plane IM again, and becomes ghost and glare. In addition, this configuration can largely absorb light that has leaked from the reflection axis direction of the polarization selective transflective element A, and significantly reduce single-path ghosting.

[0162] This configuration can place a quarter wave plate between the linear polarizer E and the object. At this time, the quarter wave plate and the linear polarizer E are arranged so that the fast axis or slow axis of the quarter wave plate forms an angle of 45° with the transmission axis of the linear polarizer E. In this way, even if the light incident from the object side is linearly polarized light, imaging can be performed regardless of its polarization direction. A depolarizing element can be placed instead of the quarter wave plate. An example of the depolarizing element can use "Cosmoshine SRF" manufactured by Toyobo Co., Ltd.

[0163] In the above description of the two configurations, terms such as orthogonal (perpendicular), parallel, and 45° do not necessarily mean strictly 90°, 0°, and 45°. However, these angles are within ±5° from the desired angle, or may be within ±2° from the desired angle, or may be within ±1° from the desired angle.

[0164] Both of the above configurations can use two quarter wave plates QWP with the same structure. If the quarter wave plate QWP is ideal (i.e., it gives a phase of exactly a quarter wavelength for all wavelengths and all light incident angles within the use range), then there is no problem. However, in reality, such a quarter wave plate QWP does not exist, and the phase given to the light is different depending on the wavelength of the transmitted light, etc. In the above two configurations, when the light passes through the two quarter wave plates QWP, the phase given by the first quarter wave plate QWP1 and the second quarter wave plate QWP2 is offset, and the desired light is emitted toward the image plane side. That is, the light reflected once by each of the first transmission reflection surface and the second transmission reflection surface is emitted to the image side, and the light that has never been reflected is absorbed by the polarizer. At this time, in the case where the characteristics of the first quarter wave plate QWP1 and the second quarter wave plate QWP2 are different from each other, the unexpected light is emitted toward the image plane due to the difference, ghosting and glare occur and degrade the image quality.

[0165] In the above two types of configurations, the linear polarizer E can be an absorption type polarizer rather than a reflection type. This is because the absorption type polarizer is less likely to cause ghosting and glare caused by reflection. For the linear polarizer E, the transmittance of the absorption axis can be about 0.5% or less, or 0.15% or less, or 0.05% or less on average in the use wavelength range. This configuration can effectively suppress ghost light that will reach the image plane without being reflected by the reflective surface. In particular, when the use wavelength range is wide, it is difficult to maintain the transmittance of the absorption axis of the polarizer low, but multiple polarizers can be used in layers to obtain the desired characteristics. The linear polarizer E can use, for example, "ACE-125U" or "VHC-12UL2S" manufactured by Nippon Kayaku Co., Ltd., or "XP42HE" manufactured by Edmund Optics Japan Co., Ltd. in the visible range. For example, a linear polarizer having an extremely low transmittance of the absorption axis can be obtained by stacking "ACE-125U" and "SHC-115U" manufactured by Nippon Kayaku Co., Ltd. By stacking a plurality of polarizers in this manner, resistance to degradation over time can be improved.

[0166] It is assumed that the above two types of configurations are used in combination with an image sensor including an optical low-pass filter. At this time, the relative angle between the transmission axis of the polarizer closest to the image plane and the fast axis of the birefringence plate closest to the object among the birefringence plates of the optical low-pass filter can be 45° or 135°. This configuration can provide a low-pass effect similar to the low-pass effect of a common optical system (for example, unlike a general refractive optical system, it does not have polarization dependence). Alternatively, a quarter wave plate can be deployed on the image side of the polarizer closest to the image plane. In that case, the transmission axis of the polarizer closest to the image plane and the fast axis of the quarter wave plate can be set to 45° or 135°. This configuration emits circularly polarized light toward the image sensor, thereby providing a low-pass effect similar to the low-pass effect of a common optical system. Alternatively, a plastic molded lens with large birefringence can be placed on the image side of the polarizer closest to the image plane to make the emitted light pseudo-randomly polarized, and a low-pass effect similar to the low-pass effect of a common optical system can be obtained.

[0167] In the above two types of configurations, each of the polarization selective transmissive reflective element, the quarter wave plate and the linear polarizer can be circular, rectangular or polygonal. In terms of manufacturing cost, shapes that can be laid out on a flat surface without any margin (such as rectangles and regular hexagons) may be suitable because each element can be used without waste. Among these optical elements, those made mainly of polymer materials can be obtained at low cost. In the case of using such elements, they can be bonded to glass or resin, for example, as described above, to ensure sufficient surface accuracy. This form can eliminate material loss by bonding them in large sizes and by cutting out the amount of rectangles from it. As described above, in the above two types of configurations, the orientation between the elements is important. Rectangular elements can easily ensure the shape of the components and the orientation of the components (for example, fast axis, slow axis, transmission axis, absorption axis, transmission axis and reflection axis) for each component, and simplify or omit the adjustment of the orientation.

[0168] In the optical system according to each example, the lens may be made of a resin material or a glass material. However, the lens placed between the first and second transflective surfaces may have low birefringence.

[0169] The optical system according to each example includes a first refractive lens L1, a first transflective surface HM1, a quarter wave plate QWP, and a second transflective surface HM2 in order from the object side to the image side. During focusing, the first transflective surface HM1 moves in the optical axis direction. During focusing, the first refractive lens L1 does not move, or moves so as to change the distance in the optical axis direction between the first refractive lens L1 and the first transflective surface HM1. The first refractive lens L1 is separated from each of the first transflective surface HM1 and the second transflective surface HM2.

[0170] Alternatively, the optical system according to each example includes a first refractive lens L1, a first transflective surface HM1, a quarter wave plate QWP, a second transflective surface HM2, and a second refractive lens L2 in order from the object side to the image side. During focusing, the first transflective surface HM1 moves in the optical axis direction. During focusing, the second refractive lens L2 does not move, or the distance in the optical axis direction between the second refractive lens L2 and the first transflective surface HM1 changes. The second refractive lens L2 is separated from each of the first transflective surface HM1 and the second transflective surface HM2.

[0171] The optical system according to each example may include a third refractive lens disposed on the object side of the first transflective surface HM1, separated from the first transflective surface HM1, and configured to move integrally with the first transflective surface HM1 during focusing. The optical system according to each example may include a fourth refractive lens disposed outside a region between the first transflective surface HM1 and the second transflective surface HM2, and moving in the optical axis direction during focusing.

[0172] The optical system according to each example will be described in detail below.

[0173] Example 1

[0174] Reference now Figure 3 , Figure 4A and Figure 4B , a description will be given of an optical system OS1 according to Example 1. Figure 3 : is a cross-sectional view of the optical system OS1. The optical system OS1 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. In addition, a quarter wave plate QWP is disposed on the image side of the first transflective surface HM1.

[0175] Figure 4A is an aberration diagram of the optical system OS1 in a focused state at infinity (on the object), and Figure 4B It is an aberration diagram of the optical system OS1 in the focused state at a close distance (on the object). In the spherical aberration diagram, Fno represents the F number. The spherical aberration diagram illustrates the amount of spherical aberration for the d line (wavelength 587.6nm), g line (wavelength 435.8nm), C line (wavelength 656.3nm) and F line (wavelength 486.1nm). In the astigmatism diagram, S indicates the amount of astigmatism on the sagittal image plane, and M indicates the amount of astigmatism on the meridional image plane. The distortion diagram illustrates the amount of distortion for the d line. The chromatic aberration diagram illustrates the amount of chromatic aberration for the g line, C line and F line. ω is the half angle of view (°). obj represents the focusing position (the distance from the image plane IM to the focusing surface) (unit: mm). The above definition is similarly applicable to subsequent aberration diagrams.

[0176] During focusing, the optical system OS1 integrally moves the aperture stop SP and the lens unit including the first transflective surface HM1 in the optical axis direction. Figure 1 , the bottom arrow indicates the lens unit to be moved and the direction of movement during focusing from infinity to close distance. Figure 3 In the figure, the arrow points to the object side, indicating that the lens moves toward the object side during focusing from infinity to close distance. This applies similarly to the subsequent light path diagrams.

[0177] In the optical system OS1 , the lens closest to the object corresponds to the first refractive lens L1 .

[0178] Example 2

[0179] Reference now Figure 5 , Fig. 6A and Figure 6B , a description will be given of an optical system OS2 according to Example 2. Figure 5 It is a cross-sectional view of the optical system OS2. Fig. 6A is an aberration diagram of the optical system OS2 in the infinity focus state, and Figure 6B It is an aberration diagram of the optical system OS2 in the focused state at a close distance.

[0180] The optical system OS2 includes a plurality of lenses (lens units) and a sensor protection glass in sequence from the object side to the image plane IM side. In addition, a quarter wave plate QWP is disposed on the image side of the first transmission reflection surface HM1, sandwiching a piece of flat glass. This configuration can easily improve the surface accuracy of the reflection surface. In this example, the quarter wave plate QWP is incorporated into the optical path diagram and the numerical value as a flat plate with a thickness of 0.1 mm, but this has little effect on the aberrations, and the presence or absence of this thickness does not affect the essence of each example, so the thickness of the quarter wave plate QWP is omitted in Example 1. Thereafter, the thickness of the quarter wave plate QWP, the transmission reflection surface, etc. can be omitted. During focusing, the optical system OS2 integrally moves the lens unit (including the aperture stop SP) on the object side of the meniscus lens with the convex surface facing the object side in the optical axis direction.

[0181] In the optical system OS2 , for example, the lens closest to the object corresponds to the first refractive lens L1 , the third refractive lens, and the fourth refractive lens, and the lens closest to the image plane corresponds to the second refractive lens L2 .

[0182] Example 3

[0183] Reference now Figure 7 , Fig. 8A and Figure 8B , a description will be given of an optical system OS3 according to Example 3. Figure 7 It is a cross-sectional view of the optical system OS3. Fig. 8A The aberration diagram of the optical system OS3 in the infinity focus state is illustrated, and Figure 8B The figure shows an aberration diagram of the optical system OS3 in a focused state at a close distance.

[0184] The optical system OS3 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. In addition, a quarter wave plate QWP is disposed on the image side of the first transmissive reflective surface HM1 via a convex lens. During focusing, the optical system OS3 integrally moves seven lens units (including the flat plate and excluding the quarter wave plate QWP) from the object side and the aperture stop SP in the optical axis direction.

[0185] In the optical system OS3 , for example, the lens closest to the object corresponds to the first refractive lens L1 , the third refractive lens, and the fourth refractive lens, and the lens closest to the image plane corresponds to the second refractive lens L2 .

[0186] Example 4

[0187] Reference now Fig. 9 , Fig. 10A and Fig. 10B , a description will be given of an optical system OS4 according to Example 4. Fig. 9 It is a cross-sectional view of the optical system OS4. Fig. 10A is an aberration diagram of the optical system OS4 in the infinity focus state, and Fig. 10B It is an aberration diagram of the optical system OS4 in the focused state at a close distance.

[0188] The optical system OS4 includes a plurality of lenses (lens units) and a sensor protection glass in sequence from the object side to the image plane IM side. In addition, a quarter wave plate QWP is disposed on the image side of the first transmission reflection surface HM1. During focusing, the optical system OS4 integrally moves seven lens units immediately behind the aperture stop SP (for example, next to the aperture stop SP) and disposed on the image side of the aperture stop SP in the optical axis direction. In addition, image stabilization can be performed by moving the fourth and fifth bonded lenses (image stabilization unit) counted from the object side in a direction perpendicular to the optical axis.

[0189] In the optical system OS4, for example, the lens closest to the object corresponds to the first refractive lens L1, the lens immediately after the aperture stop SP corresponds to the third and fourth refractive lenses, and the lens closest to the image plane corresponds to the second refractive lens L2.

[0190] Example 5

[0191] Reference now Fig.11 , Fig. 12A and Fig. 12B , a description will be given of an optical system OS5 according to Example 5. Fig.11 It is a cross-sectional view of the optical system OS5. Fig. 12A is an aberration diagram of the optical system OS5 in the infinity focus state, and Fig. 12BIt is an aberration diagram of the optical system OS5 in the focused state at a close distance.

[0192] The optical system OS5 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. In addition, a quarter wave plate QWP is disposed on the image side of the first transmissive reflective surface HM1. During focusing, the optical system OS5 integrally moves in the optical axis direction three lens units immediately following the aperture stop SP (e.g., next to the aperture stop SP) and disposed on the image side of the aperture stop SP.

[0193] In the optical system OS5, for example, the lens closest to the object corresponds to the first refractive lens L1, the lens immediately after the aperture stop SP corresponds to the third and fourth refractive lenses, and the lens closest to the image plane corresponds to the second refractive lens L2.

[0194] Example 6

[0195] Reference now Fig.13 , Fig.14A and Fig. 14B , a description will be given of the optical system OS6 according to Example 6. Fig.13 It is a cross-sectional view of the optical system OS6. Fig.14A is an aberration diagram of the optical system OS6 in the infinity focus state, and Fig. 14B It is an aberration diagram of the optical system OS6 in the focusing state at a close distance.

[0196] The optical system OS6 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. A quarter wave plate QWP is disposed on the image side of the first transmissive reflective surface HM1. During focusing, the optical system OS6 integrally moves the aperture stop SP and two lenses immediately following the aperture stop SP (e.g., next to the aperture stop SP) and disposed on the image side of the aperture stop SP in the optical axis direction.

[0197] In the optical system OS6 , for example, a lens closest to the object corresponds to the first refractive lens L1 , and a lens closest to the image plane corresponds to the second refractive lens L2 .

[0198] Example 7

[0199] Reference now Fig.15 , Fig.16A and Fig. 16B , a description will be given of the optical system OS7 according to Example 7. Fig.15 It is a cross-sectional view of the optical system OS7. Fig.16A is an aberration diagram of the optical system OS7 in the infinity focus state, and Fig. 16BIt is an aberration diagram of the optical system OS7 in the focusing state at a close distance.

[0200] The optical system OS7 includes a plurality of lenses (lens units) and a sensor protection glass in sequence from the object side to the image plane IM side. In addition, a quarter wave plate QWP is disposed on the image side of the first transmission reflection surface HM1. During focusing, the optical system OS7 integrally moves the aperture stop SP, the lens immediately behind the aperture stop SP (for example, next to the aperture stop SP) and disposed on the object side of the aperture stop SP, and five lenses (including a flat plate) disposed next to the aperture stop SP and on the image side of the aperture stop SP in the optical axis direction. Image stabilization can be performed by moving the lens (image stabilization unit) immediately behind the aperture stop SP (for example, next to the aperture stop SP) and disposed on the image side of the aperture stop SP in a direction orthogonal to the optical axis.

[0201] In the optical system OS7, for example, the lens closest to the object corresponds to the first refractive lens L1, the lens immediately following the aperture stop SP (for example, next to the aperture stop SP) and disposed on the object side of the aperture stop SP corresponds to the third and fourth refractive lenses, and the lens closest to the image plane corresponds to the second refractive lens L2.

[0202] Example 8

[0203] Reference now Fig.17 , Fig.18A and Fig.18B , a description will be given of the optical system OS8 according to Example 8. Fig.18A The aberration diagram of the optical system OS8 in the infinity focus state is illustrated, and Fig.18B The figure shows an aberration diagram of the optical system OS8 in a focused state at a close distance.

[0204] The optical system OS8 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS8 integrally moves four lenses (including a flat plate and excluding a quarter wave plate) immediately behind the aperture stop SP (for example, next to the aperture stop SP) and disposed on the image side of the aperture stop SP in the optical axis direction. In addition, image stabilization can be performed by moving a cemented lens (image stabilization unit) immediately in front of the aperture stop SP (for example, next to the aperture stop SP) and disposed on the object side of the aperture stop SP in a direction orthogonal to the optical axis.

[0205] In the optical system OS8, for example, the lens closest to the object corresponds to the first refractive lens L1, the lens disposed immediately behind the second transmissive reflective surface HM2 (for example, next to the second transmissive reflective surface HM2) corresponds to the fourth refractive lens, and the lens closest to the image plane corresponds to the second refractive lens L2.

[0206] Example 9

[0207] Reference now Fig.19 , Fig. 20A and Fig. 20B , a description will be given of the optical system OS9 according to Example 9. Fig.19 It is a cross-sectional view of the optical system OS9. Fig. 20A is an aberration diagram of the optical system OS9 in the infinity focus state, and Fig. 20B It is an aberration diagram of the optical system OS9 in the focused state at a close distance.

[0208] The optical system OS9 includes a plurality of lenses (lens units) and a sensor protection glass in sequence from the object side to the image plane IM side. During focusing, the optical system OS9 integrally moves the aperture stop SP and two lenses immediately behind the aperture stop SP (for example, next to the aperture stop SP) and arranged on the image side of the aperture stop SP in the optical axis direction.

[0209] In the optical system OS9, for example, the lens closest to the object corresponds to the first refractive lens L1, and the lenses immediately after the aperture stop SP correspond to the third and fourth refractive lenses.

[0210] Example 10

[0211] Reference now Fig.21 , Fig.22A and Fig. 22B , a description will be given of an optical system OS10 according to Example 10. Fig.21 It is a cross-sectional view of the optical system OS10. Fig.22A is an aberration diagram of the optical system OS10 in the infinity focus state, and Fig. 22B 2 is an aberration diagram of the optical system OS10 in a focused state at a close distance.

[0212] The optical system OS10 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS10 integrally moves the aperture stop SP, and the lenses disposed immediately behind the aperture stop SP (e.g., next to the aperture stop SP and on the image side of the aperture stop SP) and immediately in front of the aperture stop SP (e.g., next to the aperture stop SP and on the object side of the aperture stop SP) in the optical axis direction, and also moves the two lenses on the image side thereof as an integral floating unit by different amounts in the optical axis direction.

[0213] In the optical system OS10 , for example, a lens closest to the object corresponds to the first refractive lens L1 , the third refractive lens, and the fourth refractive lens, and a lens closest to the image plane corresponds to the second refractive lens L2 .

[0214] Example 11

[0215] Reference now Fig.23 , Fig.24A and Fig. 24B , a description will be given of an optical system OS11 according to Example 11. Fig.23 It is a cross-sectional view of the optical system OS11. Fig.24A 1 and 2 show aberration diagrams of the optical system OS11 in an infinity focused state, and Fig. 24B The diagram shows aberration diagrams of the optical system OS11 in a focused state at a close distance.

[0216] The optical system OS11 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS11 integrally moves the aperture stop SP and two lenses immediately following the aperture stop SP (for example, next to the aperture stop SP) and disposed on the image side of the aperture stop SP in the optical axis direction.

[0217] In the optical system OS11 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0218] Example 12

[0219] Reference now Fig.25 , Fig.26A and Fig.26B , a description will be given of the optical system OS12 according to Example 12. Fig.25 It is a cross-sectional view of the optical system OS12. Fig.26A is an aberration diagram of the optical system OS12 in the infinity focus state, and Fig.26B It is an aberration diagram of the optical system OS12 in a focused state at a close distance.

[0220] The optical system OS12 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS12 integrally moves the aperture stop SP and three lenses immediately following the aperture stop SP and on the image side of the aperture stop SP in the optical axis direction.

[0221] In the optical system OS12 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lenses immediately after the aperture stop SP correspond to the third and fourth refractive lenses.

[0222] Example 13

[0223] Reference now Fig. 27 , Fig.28A and Fig.28B , a description will be given of the optical system OS13 according to Example 13. Fig. 27 It is a cross-sectional view of the optical system OS13. Fig.28A is an aberration diagram of the optical system OS13 in the infinity focus state, and Fig.28B It is an aberration diagram of the optical system OS13 in a focused state at a close distance.

[0224] The optical system OS13 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS13 does not move a total of three lenses, i.e., two lenses closest to the object and one lens closest to the image plane, but moves the remaining lens units and the aperture stop SP integrally in the optical axis direction.

[0225] In the optical system OS13 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lenses immediately before the aperture stop SP correspond to the third and fourth refractive lenses.

[0226] Example 14

[0227] Reference now Fig.29 , Fig. 30A and Fig. 30B , a description will be given of the optical system OS14 according to Example 14. Fig.29 It is a cross-sectional view of the optical system OS14. Fig. 30A is an aberration diagram of the optical system OS14 in the infinity focus state, and Fig. 30B It is an aberration diagram of the optical system OS14 in a focused state at a close distance.

[0228] The optical system OS14 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS14 integrally moves the aperture stop SP and two lenses immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0229] In the optical system OS14 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0230] Example 15

[0231] Reference now Fig.31 , Fig.32A and Fig.32B , a description will be given of the optical system OS15 according to Example 15. Fig.31 It is a cross-sectional view of the optical system OS15. Fig.32A is an aberration diagram of the optical system OS15 in the infinity focus state, and Fig.32B It is an aberration diagram of the optical system OS15 in a focused state at a close distance.

[0232] The optical system OS15 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS15 integrally moves the aperture stop SP and two lenses immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0233] In the optical system OS15 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0234] Example 16

[0235] Reference now Fig.33 , Fig.34A and Fig.34B , a description will be given of the optical system OS16 according to Example 16. Fig.33 It is a cross-sectional view of the optical system OS16. Fig.34A is an aberration diagram of the optical system OS16 in the infinity focus state, and Fig.34B It is an aberration diagram of the optical system OS16 in a focused state at a close distance.

[0236] The optical system OS16 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS16 integrally moves the aperture stop SP and three lenses immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0237] In the optical system OS16 , for example, the lens closest to the object corresponds to a first refractive lens, and the lens immediately after the aperture stop SP corresponds to a fourth refractive lens.

[0238] Example 17

[0239] Reference now Fig.35 , Fig.36A and Fig.36B , a description will be given of the optical system OS17 according to Example 17. Fig.35 It is a cross-sectional view of the optical system OS17. Fig.36A is an aberration diagram of the optical system OS17 in the infinity focus state, and Fig.36B It is an aberration diagram of the optical system OS17 in a focused state at a close distance.

[0240] The optical system OS17 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS17 integrally moves three lenses immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0241] In the optical system OS17, the ability of the optical system to act on a single-path light that reaches the image plane as it is without being reflected by the first transmissive reflective surface HM1 or the second transmissive reflective surface HM2 is enhanced. The single-path light may not reach the image plane and may be absorbed by the polarizer. However, since the characteristics of the polarizer are not ideal, it is inevitable that the single-path light reaches the image plane to a certain extent. This configuration can prevent the ghosting caused by the single-path light from spreading to the entire image.

[0242] In the optical system OS17 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lenses immediately after the aperture stop SP correspond to the third and fourth refractive lenses.

[0243] Example 18

[0244] Reference now Fig.37 , Fig.38A and Fig.38B , a description of the optical system OS18 according to Example 18 will be given. Fig.37 It is a cross-sectional view of the optical system OS18. Fig.38A is an aberration diagram of the optical system OS18 in the infinity focus state, and Fig.38B It is an aberration diagram of the optical system OS18 in a focused state at a close distance.

[0245] The optical system OS18 includes a plurality of lenses (lens units) and a sensor protection glass in sequence from the object side to the image plane IM side. During focusing, the optical system OS18 does not move a total of two lenses, i.e., the lens closest to the object and the lens closest to the image plane, but moves the remaining lens units and the aperture stop SP integrally in the optical axis direction.

[0246] In the optical system OS18 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lenses disposed immediately in front of the aperture stop SP correspond to the third and fourth refractive lenses.

[0247] Example 19

[0248] Reference now Fig.39 , Fig.40A and Fig.40B , a description will be given of the optical system OS19 according to Example 19. Fig.39 It is a cross-sectional view of the optical system OS19. Fig.40A is an aberration diagram of the optical system OS19 in the infinity focus state, and Fig.40B It is an aberration diagram of the optical system OS19 in a focused state at a close distance.

[0249] The optical system OS19 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS19 moves the aperture stop SP and the lens immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in an integrated manner in the optical axis direction, and also moves the two lenses closest to the image plane as an integrated floating unit by different amounts in the optical axis direction.

[0250] In the optical system OS19 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0251] Example 20

[0252] Reference now Fig.41 , Fig.42A and Fig.42B , a description will be given of the optical system OS20 according to Example 20. Fig.41 It is a cross-sectional view of the optical system OS20. Fig.42A is an aberration diagram of the optical system OS20 in the infinity focus state, and Fig.42B 2 is an aberration diagram of the optical system OS20 in a focused state at a close distance.

[0253] The optical system OS20 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS20 integrally moves the aperture stop SP and two lenses immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0254] In the optical system OS20 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens disposed immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0255] Example 21

[0256] Reference now Fig.43 , Fig.44A and Fig.44B , a description will be given of the optical system OS21 according to Example 21. Fig.43 It is a cross-sectional view of the optical system OS21. Fig.44A is an aberration diagram of the optical system OS21 in the infinity focus state, and Fig.44B : is an aberration diagram of the optical system OS21 in a focused state at a close distance.

[0257] The optical system OS21 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS21 moves one lens immediately following the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0258] In the optical system OS21 , for example, a lens closest to the object corresponds to the first refractive lens L1 .

[0259] Example 22

[0260] Reference now Fig.45 , Fig.46A and Fig.46B , a description will now be given of the optical system OS22 according to Example 22. Fig.45 It is a cross-sectional view of the optical system OS22. Fig.46A The aberration diagram of the optical system OS22 in the infinity focus state is shown, and Fig.46B The diagram shows aberration diagrams of the optical system OS22 in a focused state at a close distance.

[0261] The optical system OS22 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS22 moves two cemented lenses, the fifth and sixth lenses from the object side, in the optical axis direction.

[0262] In the optical system OS22 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0263] Example 23

[0264] Reference now Fig.47 , Fig.48A and Fig.48B , a description will be given of the optical system OS23 according to Example 23. Fig.47 A cross-sectional view of the optical system OS23 is shown. Fig.48A The aberration diagram of the optical system OS23 in the infinity focus state is shown, and Fig.48B The diagram shows aberration diagrams of the optical system OS23 in a focused state at a close distance.

[0265] The optical system OS23 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS23 integrally moves the aperture stop SP and the lens units except the lens closest to the image plane in the optical axis direction.

[0266] In the optical system OS23 , for example, a lens closest to the object corresponds to the first refractive lens L1 , the third refractive lens, and the fourth refractive lens, and a lens closest to the image plane corresponds to the second refractive lens L2 .

[0267] Example 24

[0268] Reference now Fig.49 , Fig.50A and Fig.50B , a description will be given of the optical system OS24 according to Example 24. Fig.49 A cross-sectional view of the optical system OS24 is illustrated. Fig.50A 1 and 2 show aberration diagrams of the optical system OS24 in an infinity focused state, and Fig.50B The diagram shows an aberration diagram of the optical system OS24 in a focused state at a close distance.

[0269] The optical system OS24 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS24 moves the sixth lens counted from the object side in the optical axis direction.

[0270] In the optical system OS24 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens having the first transflective surface HM1 corresponds to the fourth refractive lens.

[0271] Example 25

[0272] Reference now Fig.51 , Fig.52A and Fig.52B , a description will be given of the optical system OS25 according to Example 25. Fig.51 A cross-sectional view of the optical system OS25 is shown. Fig.52A is an aberration diagram of the optical system OS25 in the infinity focus state, and Fig.52B It is an aberration diagram of the optical system OS25 in a focused state at a close distance.

[0273] The optical system OS25 includes a plurality of lenses (lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS25 moves a flat plate immediately behind the aperture stop SP and disposed on the image side of the aperture stop SP in the optical axis direction.

[0274] In the optical system OS25 , for example, the lens closest to the object corresponds to the first refractive lens L1 .

[0275] Example 26

[0276] Reference now Fig.53 , Fig.54A and Fig.54B , a description will be given of the optical system OS26 according to Example 26. Fig.53 It is a cross-sectional view of the optical system OS26. Fig.54A is an aberration diagram of the optical system OS26 in the infinity focus state, and Fig.54B It is an aberration diagram of the optical system OS26 in a focused state at a close distance.

[0277] The optical system OS26 includes a plurality of lenses (a plurality of lens units) and a sensor protection glass in order from the object side to the image plane IM side. During focusing, the optical system OS26 integrally moves the aperture stop SP and three lenses except the lens closest to the object.

[0278] In the optical system OS26 , for example, the lens closest to the object corresponds to the first refractive lens L1 , and the lens immediately after the aperture stop SP corresponds to the fourth refractive lens.

[0279] Now, descriptions of numerical examples 1 to 26 corresponding to examples 1 to 26, respectively, will be given. In the surface data of each numerical example, the surface number i represents the i-th surface counted from the pupil plane side. r represents the radius of curvature of the i-th surface, and d (mm) represents the lens thickness or air distance between the i-th surface and the (i+1)-th surface. nd represents the refractive index of the material of the i-th optical element for the d-line, and νd represents the Abbe number of the optical member based on the d-line. The Abbe number νd of a certain material is expressed as follows:

[0280] vd=(Nd-1) / (NF-NC)

[0281] Wherein Nd, NF and NC are refractive indices for d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) among Fraunhofer lines, respectively. SP represents an aperture stop.

[0282] An asterisk "*" next to a surface number means that the surface has an aspherical shape. The aspherical shape is expressed as follows:

[0283]

[0284] Where x is the displacement at a height h from the surface vertex in the optical axis direction, R is the paraxial curvature radius, k is the cone constant, and Ai: (i = 2, 4, 6, 8...) is the aspheric coefficient of each order. "e±XX" in each aspheric coefficient means "×10 ±XX ”.

[0285] In each numerical example, d, focal length (mm), F number (Fno) and half angle of view (°) are all values ​​when the optical system according to each example is in a state of focusing on an object at infinity. "Back focal length (BF)" is the distance on the optical axis from the last lens surface (the lens surface closest to the image plane) to the paraxial image plane expressed in air equivalent length. "Total lens length" is the distance on the optical axis from the frontmost lens surface (the lens surface closest to the object) to the last surface of the optical system plus the back focal length. "Lens unit" includes one or more lenses.

[0286] Numerical Example 1

[0287] Unit: mm

[0288] Surface data

[0289]

[0290] Aspheric surface data

[0291] Surface 1

[0292] K=0.00000e+00 A4=1.75368e-06 A6=-2.08107e-09 Surface 2

[0293] K=0.00000e+00 A4=-1.06144e-06 A6=-1.12963e-08

[0294] Surface 4

[0295] K=0.00000e++00 A2=-5.47088e-03 A4=-1.57901e-05 A6=2.13974e-08 A 8=7.49429e-1 2

[0296] Surface 5

[0297] K=0.00000e+00 A4=-3.35715e-06 A6=5.58849e-09 A 8=-1.34412e-11 A10=1.23184e-14 A12=-8.60860e-21

[0298] Surface 6

[0299] K=0.00000e+00 A 4=2.67533e-05 A 6=-6.60403e-08 A 8=8.83817e-11 A10=-3.54229e-13 A12=2.37426e-16

[0300] Surface 7

[0301] K=0.00000e+00 A4=2.21090e-05 A6=-4.76083e-08 A 8=9.17449e-11 A10=-3.35061e-13

[0302] Surface 8

[0303] K=0.00000e+00 A4=-8.37494e-07 A 6=9.41948e-10 A 8=8.14789e-12 A10=-1.12477e-13 A12=3.58736e-16

[0304] Surface 9

[0305] K=0.00000e+00 A4=2.21090e-05 A 6=-4.76083e-08 A 8=9.17449e-11 A10=-3.35061e-13

[0306] Surface 10

[0307] K=0.00000e+00 A 4=2.67533e-05 A 6=-6.60403e-08 A 8=8.83817e-11 A10=-3.54229e-13 A12=2.37426e-16

[0308] Surface 11

[0309] K=0.00000e+00 A4=-3.35715e-06 A 6=5.58849e-09 A 8=-1.34412e-11 A10=1.23184e-14 A12=-8.60860e-21

[0310] Surface 12

[0311] K=0.00000e+00 A4=2.67533e-05 A 6=-6.60403e-08 A 8=8.83817e-11 A10=-3.54229e-13 A12=2.37426e-16

[0312] Surface 13

[0313] K=0.00000e+00 A4=2.21090e-05 A 6=-4.76083e-08 A 8=9.17449e-11 A10=-3.35061e-13

[0314] Surface 14

[0315] K=0.00000e+00 A4=-8.37494e-07 A6=9.41948e-10 A8=8.14789e-12 A10=-1.12477e-13 A12=3.58736e-16

[0316] Surface 15

[0317] K=0.00000e+00 A2=-4.12994e-02 A4=-1.43658e-05 A6=-9.85889e-09 A8=-1.01161e-10

[0318] Various data

[0319]

[0320]

[0321] Numerical example 2 Unit: mm Surface data

[0322]

[0323] Aspheric surface data

[0324] Surface 1

[0325] K=0.00000e+00 A 4=-4.06466e-06 A6=1.03932e-08 A8=-1.67472e-11 A10=1.02529e-14

[0326] Surface 2

[0327] K=0.00000e+00 A4=-3.12852e-06 A6=1.11218e-08 A 8=-2.12628e-11 A10=1.94691e-14 A12=-6.84758e-18

[0328] Surface 18

[0329] K=0.00000e+00 A4=2.10433e-05 A 6=-2.77702e-08

[0330] Surface 19

[0331] K=0.00000e+00 A 4=2.40984e-05 A 6=-2.49256e-08

[0332] Surface 28

[0333] K=0.00000e+00 A4=7.07409e-06 A6=-7.48712e-09 A8=2.28141e-11 A10=-

[0334] 3.65416e-14

[0335] Various data

[0336]

[0337] Numerical Example 3

[0338] Unit: mm

[0339] Surface data

[0340]

[0341]

[0342] Aspheric surface data

[0343] Surface 1

[0344] K=0.00000e+00 A4=1.82053e-06 A6=1.07157e-09

[0345] Surface 2

[0346] K=0.00000e+00 A4=1.11630e-06 A 6=2.22067e-09

[0347] Various data

[0348]

[0349] Numerical Example 4

[0350] Unit: mm

[0351] Surface data

[0352]

[0353]

[0354]

[0355] Aspheric surface data

[0356] Surface 15

[0357] K=0.00000e+00 A 4=-8.84207e-06 A 6=-1.26449e-08

[0358] Surface 25

[0359] K=0.00000e+00 A4=-6.31962e-05 A 6=2.28241e-08

[0360] Surface 26

[0361] K=0.00000e+00 A4=-6.21 297e-05 A 6=4.62364e-08

[0362] Various data

[0363]

[0364] Numerical Example 5

[0365] Unit: mm

[0366] Surface data

[0367]

[0368]

[0369] Aspheric surface data

[0370] Surface 3

[0371] K=0.00000e+00 A 4=1.63267e-07 A 6=2.93219e-09

[0372] Surface 4

[0373] K=0.00000e+00 A4=1.17377e-06 A6=8.47197e-10 A8=-1.15699e-12 A10=-4.32516e-15

[0374] Surface 11

[0375] K=0.00000e+00 A4=-2.19247e-06 A6=-2.62246e-09 A8=2.21713e-12 A10=-2.22878e-14 A12=1.58408e-17

[0376] Surface 13

[0377] K=0.00000e+00 A4=-2.19247e-06 A6=-2.62246e-09 A8=2.21713e-12 A10=-2.22878e-14 A12=1.58408e-17

[0378] Surface 17

[0379] K=0.00000e+00 A4=-2.19247e-06 A6=-2.62246e-09 A8=2.21713e-12 A10=-2.22878e-14 A12=1.58408e-17

[0380] Surface 20

[0381] K=0.00000e+00 A4=2.63824e-05 A6=-1.06717e-07

[0382] Various data

[0383]

[0384] Numerical example 6 Unit: mm Surface data

[0385]

[0386] Aspheric surface data

[0387] Surface 9

[0388] K=0.00000e+00 A4=-8.77810e-07 A6=1.97233e-11 A8=-1.93497e-13 A10=2.59713e-16 A12=-1.33641e-19

[0389] Surface 11

[0390] K=0.00000e+00 A4=-8.77810e-07 A6=1.97233e-11 A 8=-1.93497e-13 A10=2.59713e-16 A12=-1.33641e-19

[0391] Surface 15

[0392] K=0.00000e+00 A4=-8.77810e-07 A 6=1.97233e-11 A 8=-1.93497e-13A10=2.59713e-16 A12=-1.33641e-19

[0393] Surface 19

[0394] K=0.00000e+00 A4=1.32990e-07 A6=1.09167e-09 A 8=-5.37842e-13 A10=2.07993e-16

[0395] Various data

[0396]

[0397]

[0398] Numerical example 7 Unit: mm Surface data

[0399]

[0400] Aspheric surface data

[0401] Surface 3

[0402] K=0.00000e+00 A4=2.80058e-05 A 6=-1.86749e-08 A 8=5.41443e-12 A10=5.11302e-14

[0403] Surface 4

[0404] K=0.00000e+00 A 4=2.7131 9e-05 A 6=-2.40373e-08

[0405] Surface 10

[0406] K=0.00000e+00 A 4=1.80747e-06 A 6=5.34299e-10

[0407] Surface 15

[0408] K=0.00000e+00 A4=2.89798e-06 A 6=4.44896e-09 A 8=2.67425e-12

[0409] Surface 21

[0410] K=0.00000e+00 A4=2.89798e-06 A 6=4.44896e-09 A 8=2.67425e-12

[0411] Surface 26

[0412] K=0.00000e+00 A4=-2.06753e-06 A 6=7.40511e-09 A 8=2.47090e-11

[0413] Surface 27

[0414] K=0.00000e+00 A4=1.08328e-05 A6=-2.04810e-08 A 8=1.01300e-10 A10=-9.40040e-14

[0415] Various data

[0416]

[0417] Numerical Example 8

[0418] Unit: mm

[0419] Surface data

[0420]

[0421]

[0422] Aspheric surface data

[0423] Surface 1

[0424] K=0.00000e+00 A 4=4.43125e-08 A 6=8.19697e-10

[0425] Surface 2

[0426] K=0.00000e+00 A 4=1.51907e-06 A 6=1.25991e-09

[0427] Surface 19

[0428] K=0.00000e+00 A 4=-5.63465e-07 A 6=-1.32044e-09 A 8=-6.5%30e-12A10=-3.66076e-15

[0429] Surface 25

[0430] K=0.00000e+00 A 4=5.89089e-08 A6=7.14844e-09

[0431] Surface 26

[0432] K=0.00000e+00 A4=9.86729e-06 A6=-5.58092e-09 A 8=3.90470e-11 A10=-5.62801e-14

[0433] Various data

[0434]

[0435] Numerical example 9 Unit: mm Surface data

[0436] Aspherical surface data 1st surface

[0437] K=0.00000e+00 A 2=-2.92248e-02 A4=-1.66006e-04 A6=1.48542e-06 A8=-3.34281e-08 A10=2.02751e-10 A12=1.57208e-12

[0438] Surface 2

[0439] K=0.00000e+00 A4=7.63633e-05 A6=5.33636e-06 A8=-1.52003e-07 A10=3.33154e-09 A12=-2.42253e-11

[0440] Surface 4

[0441] K=0.00000e+00 A4=-3.88719e-04 A6=-1.52411e-05 A8=2.17573e-06 A10=-1.53277e-07

[0442] Surface 5

[0443] K=0.00000e+00 A 4=-2.17211 e-04 A 6=1.28090e-05 A 8=-8.94365e-07

[0444] Surface 6

[0445] K=0.00000e+00 A 4=-5.58108e-04 A 6=1.87674e-05 A 8=-1.36199e-06

[0446] Surface 7

[0447] K=0.00000e+00 A4=-3.42153e-04 A6=6.88122e-06 A8=-2.36999e-07 A10=-8.92100e-10 A12=2.97739e-13

[0448] Surface 8

[0449] K=0.00000e+00 A4=5.15689e-05 A 6=-1.88653e-05 A 8=3.12701e-07 A10=-1.02106e-08 A12=5.08818e-11

[0450] Surface 9

[0451] K=0.00000e+00 A4=1.00441e-04 A 6=-2.22495e-05 A 8=4.90051e-07A10)=-9.61 925e-09

[0452] Surface 10

[0453] K=0.00000e+00 A 4=-4.29042e-05 A 6=3.45895e-06 A 8=-2.86769e-08 A10=-2.33169e-09 A12=2.61879e-11 A14=-1.75383e-14 A16=-2.25865e-16

[0454] Surface 11

[0455] K=0.00000e+00 A 4=1.00441e-04 A 6=-2.22495e-05 A 8=4.90051e-07 A10=-9.61 925e-09

[0456] Surface 12

[0457] K=0.00000e+00 A 4=5.15689e-05 A 6=-1.88653e-05 A 8=3.12701e-07A10=-1.02106e-08 A12=5.08818e-11

[0458] Surface 13

[0459] K=0.00000e+00 A4=-3.42153e-04 A6=6.88122e-06 A 8=-2.36999e-07 A10=-8.92100e-10 A12=2.97739e-13

[0460] Surface 14

[0461] K=0.00000e+00 A4=5.15689e-05 A 6=-1.88653e-05 A 8=3.12701e-07 A10=-1.02106e-08 A12=5.08818e-11

[0462] Surface 15

[0463] K=0.00000e+00 A 4=1.00441e-04 A 6=-2.22495e-05 A 8=4.90051e-07A10=-9.61925e-09

[0464] Surface 16

[0465] K=0.00000e+00 A4=-4.29042e-05 A6=3.45895e-06 A8=-2.86769e-08 A10=-2.33169e-09 A12=2.61879e-11 A14=-1.75383e-14 A16=-2.25865e-16

[0466] Surface 17

[0467] K=0.00000e+00 A 2=7.65763e-03 A 4=1.70301e-03 A 6=-2.74630e-05 A8=2.26084e-07

[0468] Various data

[0469]

[0470] Numerical Example 10

[0471] Unit: mm

[0472] Surface data

[0473]

[0474]

[0475] Aspheric surface data

[0476] Surface 1

[0477] K=0.00000e+00 A4=-1.74929e-06 A6=-8.62843e-10

[0478] Surface 2

[0479] K=0.00000e+00 A4=-4.07821e-06 A 6=-7.23767e-10

[0480] Surface 4

[0481] K=0.00000e+00 A 2=-1.22787e-02 A 4=-1.83823e-06 A 6=2.70135e-08 A8=-5.09885e-11

[0482] Surface 5

[0483] K=0.00000e+00 A4=:-2.15470e-06 A6=4.98429e-09 A8=-3.38806e-11 A10=1.31569e-13 A12=-2.13965e-16

[0484] Surface 6

[0485] K=0.00000e+00 A 4=-1.56713e-07 A 6=-6.36987e-08 A 8=8.88377e-11 A10=-2.64136e-13 A12=2.14791e-16

[0486] Surface 7

[0487] K=0.00000e+00 A 4=3.08711e-06 A 6=-4.36485e-08 A 8=1.39724e-11A10=2.33549e-15

[0488] Surface 8

[0489] K=0.00000e+00 A 2=:-1.54062e-02 A 4=-1.12202e-06 A 6=1.18269e-10A 8=5.81600e-12 A10=-5.88663e-15 A12=1.86539e-18

[0490] Surface 9

[0491] K=0.00000e+00 A 4=3.08711e-06 A 6=-4.36485e-08 A 8=1.39724e-11A10=2.33549e-15

[0492] Surface 10

[0493] K=0.00000e+00 A 4=-1.56713e-07 A 6=-6.36987e-08 A 8=8.88377e-11A10=-2.64136e-13 A12=2.14791e-16

[0494] Surface 11

[0495] K=0.00000e+00 A4=-2.15470e-06 A 6=4.98429e-09 A 8=-3.38806e-11 A10=1.31569e-13 A12=-2.13965e-16

[0496] Surface 12

[0497] K=0.00000e+00 A 4=-1.56713e-07 A 6=-6.36987e-08 A 8=8.88377e-11 A10=-2.64136e-13 A12=2.14791e-16

[0498] Surface 13

[0499] K=0.00000e+00 A 4=3.08711e-06 A 6=-4.36485e-08 A 8=1.39724e-11A10=

[0500] 2.33549e-1 5

[0501] Surface 14

[0502] K=0.00000e+00 A 2=:-1.54062e-02 A 4=-1.12202e-06 A 6=1.18269e-10A 8=5.81600e-12 A10=-5.88663e-15 A12=1.86539e-18

[0503] Surface 15

[0504] K=0.00000e+00 A 2=-3.00572e-02 A4=-1.07875e-05 A 6=-1.07802e-08 A8=4.04651e-13

[0505] Various data

[0506]

[0507]

[0508]

[0509] Numerical example 11 Unit: mm Surface data

[0510] Aspheric surface data

[0511] Surface 7

[0512] K=0.00000e+00 A4=-1.27170e-06 A6=1.09638e-09 A8=-1.59118e-11 A10=6.69227e-14 A12=-1.11236e-16

[0513] Surface 9

[0514] K=0.00000e+00 A4=-1.27170e-06 A 6=1.09638e-09 A 8=-1.59118e-11A10=6.69227e-14 A12=-1.11236e-16

[0515] Surface 13

[0516] K=0.00000e+00 A4=-1.27170e-06 A 6=1.09638e-09 A 8=-1.59118e-11A10=6.69227e-14 A12=-1.11236e-16

[0517] Various data

[0518]

[0519] Numerical Example 12

[0520] Unit: mm

[0521] Surface data

[0522]

[0523] Aspheric surface data

[0524] Surface 11

[0525] K=0.00000e+00 A 4=-2.98007e-06 A 6=5.44403e-09 A 8=-5.81960e-1A10=2.52878e-13 A12=-4.19387e-16

[0526] Surface 13

[0527] K=0.000000e+00 A 4=-2.98007e-06 A 6=5.44403e-09 A 8=-5.81 960e-11A10=2.52878e-13 A12=-4.19387e-16

[0528] Surface 17

[0529] K=0.00000e+00 A 4=-2.98007e-06 A 6=5.44403e-09 A 8=-5.81960e-11A10=2.52878e-13 A12=-4.19387e-16

[0530] Various data

[0531]

[0532] Numerical Example 13

[0533] Unit: mm

[0534] Surface data

[0535]

[0536]

[0537] Aspheric surface data

[0538] Surface 12

[0539] K=0.00000e+00 A4=-2.56220e-06 A 6=-1.16511e-09 A 8=-8.21450e-12A10=2.52195e-14 A12=-4.26110e-17

[0540] Surface 14

[0541] K=0.00000e+00 A4=-2.56220e-06 A6=-1.16511e-09 A8=-8.21450e-12 A10=2.52195e-14 A12=-4.26110e-17

[0542] Surface 18

[0543] K=0.00000e+00 A 4=-2.56220e-06 A 6=-1.16511e-09 A 8=-8.21450e-12A10=2.52195e-14 A12=-4.26110e-17

[0544] Surface 22

[0545] K=0.00000e+00 A 4=2.04785e-06 A 6=-8.15703e-09

[0546] Various data

[0547]

[0548] Numerical example 14 Unit: mm Surface data

[0549]

[0550] Aspheric surface data

[0551] Surface 9

[0552] K=0.00000e+00 A4=-8.31478e-07 A 6=-2.74307e-10 A 8=1.58841e-13 A10=2.42540e-17 A12=-1.36738e-19

[0553] Surface 11

[0554] K=0.00000e+00 A 4=-8.31478e-07 A 6=-2.74307e-10 A 8=1.58841e-13 A10=2.42540e-17 A12=-1.36738e-19

[0555] Surface 15

[0556] K=0.00000e+00 A4=-8.31478e-07 A 6=-2.74307e-10 A 8=1.58841e-13 A10=2.42540e-17 A12=-1.36738e-19

[0557] Surface 19

[0558] K=0.00000e+00 A4=2.54086e-06 A 6=-5.50287e-10 A 8=1.66150e-12 A10=7.92260e-18

[0559] Various data

[0560]

[0561]

[0562] Numerical example 15 Unit: mm Surface data

[0563] Aspheric surface data

[0564] Surface 1

[0565] K=0.00000e+00 A 4=3.18032e-07A 6=2.80240e-10 A 8=-6.47939e-14 A10=3.10952e-16

[0566] Surface 2

[0567] K=0.00000e+00 A4=-1.64643e-07A 6=-1.26010e-10

[0568] Surface 7

[0569] K=0.00000e+00 A4=-7.44307e-07A6=-5.79334e-10 A8=2.09678e-14 A10=-7.96117e-16 A12=2.86214e-19

[0570] Surface 9

[0571] K=0.00000e+00 A4=-7.44307e-07A 6=-5.79334e-10 A 8=2.09678e-14 A10=-7.96117e-16 A12=2.86214e-19

[0572] Surface 13

[0573] K=0.00000e+00 A4=-7.44307e-07A 6=-5.79334e-10 A 8=2.09678e-14 A10=-7.96117e-16 A12=2.86214e-19

[0574] Surface 16

[0575] K=0.00000e+00 A 4=-4.65984e-05 A 6=-1.36407e-07

[0576] Surface 17

[0577] K=0.00000e+00 A 4=-5.41008e-05 A 6=-5.41946e-08 Various data

[0578] Numerical example 16 Unit: mm Surface data

[0579]

[0580] Aspheric surface data

[0581] Surface 7

[0582] K=0.00000e+00 A 4=-8.49441e-07A 6=4.42583e-10 A 8=:-2.29922e-12A10=3.41916e-15 A12=-2.00.408e-18

[0583] Surface 9

[0584] K=0.00000e+00 A 4=-8.49441e-07A 6=4.42583e-10 A 8=-2.29922e-12A10=3.41916e-15 A12=-2.00408e-18

[0585] Surface 13

[0586] K=0.00000e+00 A4=-8.49441e-07A 6=4.42583e-10 A 8=-2.29922e-12 A10=3.41916e-15 A12=-2.00408e-18

[0587] Various data

[0588]

[0589] Numerical example 17 Unit: mm Surface data

[0590]

[0591] Aspheric surface data

[0592] Surface 3

[0593] K=0.00000e+00 A4=1.01631e-06 A6=-2.30048e-09 A8=2.71764e-11 A10=-5.99857e-14 A12=7.06294e-17

[0594] Surface 11

[0595] K=0.00000e+00 A 4=-4.23437e-06 A 6=4.07555e-09 A 8=-6.70601 e-11A 10=2.79579e-13 A12=-4.68393e-16

[0596] Surface 13

[0597] K=0.00000e+00 A 4=-4.23437e-06 A 6=4.07555e-09 A 8=-.6.70601e-11A10=2.79579e-13 A12=-4.68393e-16

[0598] Surface 17

[0599] K=0.00000e+0(0 A 4=-4.23437e-06 A 6=4.07555e-09 A 8=-6.70601e-11A10=2.79579e-13 A12=-4.68393e-16

[0600] Various data

[0601]

[0602]

[0603] Numerical example 18 Unit: mm Surface data

[0604]

[0605] Aspheric surface data

[0606] Surface 2

[0607] K=0.00000e+00 A 4=-1.80322e-06 A 6=-4.85921 e-09

[0608] Surface 9

[0609] K=0.00000e+00 A4=-5.53212e-06 A6=-1.00677e-08 A8=2.07899e-12 A10=-6.64077e-14 A12=-8.05438e-17

[0610] Surface 11

[0611] K=0.00000e+00 A4=-5.53212e-06 A6=-1.00677e-08 A8=2.07899e-12 A10=-6.64077e-14 A12=-8.05438e-17

[0612] Surface 15

[0613] K=0.00000e+00 A4=-5.53212e-06 A6=-1.00677e-08 A8=2.07899e-12 A10=-6.64077e-14 A12=-8.05438e-17

[0614] Surface 17

[0615] K=0.00000e+00 A 4=-3.1 8242e-06 A 6=-2.57579e-08 A 8=7.82406e-11A 10=-2.38554e-13

[0616] Various data

[0617]

[0618]

[0619] Numerical example 19 Unit: mm Surface data

[0620]

[0621] Aspheric surface data

[0622] Surface 1

[0623] K=0.00000e+00 A 4=2.05760e-06 A 6=-1.20695e-09 A 8=1.87087e-11 A10=-3.04451e-14 A12=-338066e-18

[0624] Surface 2

[0625] K=0.00000e+00 A4=8.53439e-07A 6=-3.77007e-09 A 8=1.13209e-11 A10=-4.09934e-14 A12=2.20382e-17

[0626] Surface 4

[0627] K=0.00000e+00 A2=-9.94614e-03 A4=-1.13659e-05 A6=1.70344e-08 A8=1.55013e-11 A10=1.01486e-14

[0628] Surface 5

[0629] K=0.00000e+00 A4=-1.98602e-06 A6=1.24590e-09 A8=7.15980e-12 A10=-7.27344e-14

[0630] Surface 6

[0631] K=0.00000e+00 A4=1.74651e-05 A 6=-3.72923e-08 A 8=-5.19580e-11A10=7.83608e-14 A12=-7.61217e-16

[0632] Surface 7

[0633] K=0.00000e+00 A4=1.25192e-05 A 6=-2.18272e-08 A8=2.39426e-11 A10=-1.99465e-13

[0634] Surface 8

[0635] K=0.00000e+00 A4=-1.52761e-07A6=1.51824e-10 A8=-4.67105e-13 A10=-1.43466e-14 A12=6.59523e-17

[0636] Surface 9

[0637] K=0.00000e+000 A4=1.25192e-05 A6=-2.18272e-08 A8=2.39426e-11 A10=-1.99465e-13

[0638] Surface 10

[0639] K=0.000000e+00 A4=1.74651e-05 A 6=-3.72923e-08 A 8=-5.19580e-11A10=7.83608e-14 A12=-7.61217e-16

[0640] Surface 11

[0641] K=0.00000e+00 A4=-1.98602e-06 A6=1.24590e-09 A8=7.15980e-12 A10=-7.27344e-14

[0642] Surface 12

[0643] K=0.00000e+00 A4=1.74651e-05 A 6=-3.72923e-08 A 8=-5.19580e-11A10=7.83608e-14 A12=-7.61217e-16

[0644] Surface 13

[0645] K=0.00000e+00 A4=1.25192e-05 A6=-2.18272e-08 A8=2.39426e-11 A10=-1.99465e-13

[0646] Surface 14

[0647] K=0.00000e+00 A4=-1.52761e-07A6=1.51824e-10 A8=-4.67105e-13 A10=-1.43466e-14 A12=6.59523e-17

[0648] Surface 15

[0649] K=0.00000e+00 A 2=-3.67253e-02 A4=-6.47218e-06 A 6=-1.64802e-08 A8=-4.65932e-11

[0650] Various data

[0651]

[0652]

[0653] Numerical Example 20

[0654] Unit: mm

[0655] Surface data

[0656]

[0657]

[0658] Aspheric surface data

[0659] Surface 9

[0660] K=0.00000e+00 A4=-1.02932e-06 A 6=1.71899e-10 A 8=-1.82378e-12A10=4.42535e-15 A12=-4.22552e-18

[0661] Surface 13

[0662] K=0.00000e+00 A4=-1.02932e-06 A 6=1.71899e-10 A 8=-1.82378e-12A10=4.42535e-15 A 12=-4.22552e-1 8

[0663] Surface 17

[0664] K=0.00000e+00 A4=-1.02932e-06 A6=1.71899e-10 A8=-1.82378e-12 A10=4.42535e-15 A12=-4.22552e-18

[0665] Surface 22

[0666] K=0.00000e+00 A 4=4.77769e-06 A 6=3.78844e-09

[0667] Various data

[0668]

[0669] Numerical Example 21

[0670] Unit: mm Surface data

[0671] Aspheric surface data

[0672] Surface 3

[0673] K=0.00000e+00 A 4=5.29083e-06 A 6=-9.38486e-09 A 8=8.37198e-12A10=-3.53430e-1 5

[0674] Surface 4

[0675] K=0.00000e+00 A4=7.53551e-06 A 6=-8.80710e-09 A 8=8.79233e-12 A10=-3.43617e-15

[0676] Surface 16

[0677] K=0.00000e+00 A4=1.27331e-05 A 6=-1.42063e-08

[0678] Surface 17

[0679] K=0.00000e+00 A 4=1.65139e-05 A 6=-1.03897e-08 A 8=-5.14026e-12A10=8.65167e-15

[0680] Various data

[0681]

[0682] Numerical Example 22

[0683] Unit: mm Surface data

[0684]

[0685] Aspheric surface data

[0686] Surface 3

[0687] K=0.00000e+00 A 4=-6.28932e-06 A 6=-1.79799e-08 A 8=-1.23977e-11A 10=3.86980e-14

[0688] Surface 4

[0689] K=0.00000e+00 A 4=-3.97301e-06 A 6=-1.70340e-08 A 8=-1.09235e-11A10=4.30624e-14

[0690] Surface 13

[0691] K=0.00000e-+00 A4=-1.56151e-06 A 6=3.94324e-11 A 8=3.89519e-12A10=-1.21217e-14 A12=1.18319e-17

[0692] Surface 14

[0693] K=0.000000e+00 A 4=4.92297e-08 A 6=6.76632e-10

[0694] Surface 15

[0695] K=0.00000e+00 A4=-1.56151e-06 A 6=3.94324e-11 A 8=3.89519e-12 A10=-1.21217e-14 A12=1.18319e-17

[0696] Surface 19

[0697] K=0.00000e+00 A4=-1.56151e-06 A 6=3.94324e-11 A 8=3.89519e-12 A10=-1.21217e-14 A12=1.18319e-17

[0698] Surface 20

[0699] K=0.00000e+00 A 4=4.92297e-08 A 6=6.76632e-10

[0700] Various data

[0701]

[0702] Numerical Example 23

[0703] Unit: mm

[0704] Surface data

[0705]

[0706]

[0707] Aspheric surface data

[0708] Surface 2

[0709] K=0.00000e+00 A 4=4.08957e-07A 6=-5.56282e-10

[0710] Surface 9

[0711] K=0.00000e+00 A4=-2.15617e-06 A6=-3.25248e-09 A8=1.70004e-11 A10=-9.65529e-14 A12=1.62524e-16

[0712] Surface 11

[0713] K=0.00000e+00 A4=-2.15617e-06 A 6=-3.25248e-09 A 8=1.70004e-11 A10=-9.65529e-14 A12=1.62524e-16

[0714] Surface 15

[0715] K=0.00000e+00 A4=-2.15617e-06 A 6=-3.25248e-09 A 8=1.70004e-11 A10=-9.65529e-14 A12=1.62524e-16

[0716] Surface 19

[0717] K=0.00000e+00 A4=4.46773e-07A6=-5.83941e-09 A8=5.31116e-12 A10=-1.07179e-14

[0718] Various data

[0719]

[0720] Numerical Example 24

[0721] Unit: mm

[0722] Surface data

[0723]

[0724]

[0725] Aspherical data 3rd surface

[0726] K=0.000000e+00 A4=1.29859e-06 A 6=6.82258e-(9 A8=1.75850e-11 A10=-2.68142e-14

[0727] Surface 4

[0728] K=0.00000e+00 A4=4.27604e-06 A 6=9.79087e-09 A 8=1.77416e-11 A10=-1.97887e-14

[0729] Surface 14

[0730] K=0.00000e+00 A4=-6.23100e-06 A 6=5.29938e-09 A 8=-4.53625e-11A10=6.33782e-14

[0731] Surface 15

[0732] K=0.00000e+00 A 4=-4.46191e-06 A 6=3.27854e-09 A 8=-3.42859e-11A10=4.89042e-14

[0733] Surface 17

[0734] K=0.00000e+00 A 4=-4.46191e-06 A 6=3.27854e-09 A 8=-3.42859e-11A10=

[0735] 4.89042e-14

[0736] Surface 18

[0737] K=0.00000e+00 A 4=-6.23100e-06 A 6=5.29938e-09 A 8=-4.53625e-11 A10=6.33782e-14

[0738] Surface 20

[0739] K=0.00000e+00 A4=-6.23100e-06 A 6=5.29938e-09 A 8=-4.53625e-11 A10=6.33782e-14

[0740] Surface 21

[0741] K=0.00000e+00 A 4=-4.461 91e-06 A 6=3.27854e-09 A 8=-3.42859e-11A 10=4.89042e-14

[0742] Various data

[0743]

[0744] Numerical Example 25

[0745] Unit: mm

[0746] Surface data

[0747]

[0748]

[0749] Aspheric surface data

[0750] Surface 3

[0751] K=0.00000e+00 A4=1.29798e-006 A6=-3.96015e-09 A8=4.15359e-12 A10=-2.08355e-15

[0752] Surface 4

[0753] K=0.00000e+00 A4=3.17673e-06 A6=-3.76681e-09 A8=5.14754e-12 A10=-3.01761e-15

[0754] Surface 22

[0755] K=0.00000e+00 A 4=1.81465e-05 A 6=3.61890e-10 A 8=-5.09761e-11A10=5.10749e-14

[0756] Surface 23

[0757] K=0.00000e+00 A 4=2.06653e-05 A 6=2.60284e-09 A 8=-4.72922e-11A10=4.87368e-14

[0758] Various data

[0759]

[0760] Numerical Example 26

[0761] Unit: mm

[0762] Surface data

[0763]

[0764]

[0765] Aspheric surface data

[0766] Surface 1

[0767] K=0.00000e+00 A 4=1.88779e-07A 6=3.81432e-09 A 8=-6.92099e-1 2A10=1.47763e-14 A12=2.09285e-18

[0768] Surface 2

[0769] K=0.00000e+00 A 4=3.34279e-07A 6=4.78843e-09 A 8=-1.29872e-11 A10=2.79285e-14 A12=-1.08478e-17

[0770] Surface 4

[0771] K=0.00000e+00 A4=-1.15373e-07A6=1.61379e-08 A8=-1.23993e-10 A10=2.56881e-13 A12=1.87005e-16

[0772] Surface 5

[0773] K=0.00000e++00 A4=-4.26715e-06 A6=-7.78873e-09 A8=2.53451e-11 A10=-3.37826e-13 A12=9.95687e-16

[0774] Surface 6

[0775] K=0.00000e+00 A4=-9.31759e-06 A6=-5.59292e-08 A8=1.47485e-10 A10=-4.23025e-13 A12=-3.93468e-16

[0776] Surface 7

[0777] K=0.00000e+00 A 4=-4.47037e-06 A6=-6.44026e-08 A 8=2.05905e-10 A10=-6.27518e-13 A12=7.31725e-16

[0778] Surface 8

[0779] K=0.00000e+00 A 4=-1.37402e-06 A 6=6.20006e-09 A 8=:-1.27% 3e-11A10=6.01445e-14 A12=1.20501e-16

[0780] Surface 9

[0781] K=0.00000e+00 A4=-4.47037e-06 A 6=-6.44026e-08 A 8=2.05905e-10 A10=-6.27518e-13 A12=7.31725e-16

[0782] Surface 10

[0783] K=0.00000e+00 A4=-9.31759e-06 A6=-5.59292e-08 A8=1.51573e-10 A10=-4.08206e-13 A12=-2.41308e-16

[0784] Surface 11

[0785] K=0.00000e+00 A4=-4.26715e-06 A6=-7.78873e-09 A8=2.53451e-11 A10=-3.37826e-13 A12=9.95687e-16

[0786] Surface 12

[0787] K=0.00000e+00 A4=-9.31759e-06 A6=-5.59292e-08 A8=1.47485e-10 A10=-4.23025e-13 A12=-3.93468e-16

[0788] Surface 13

[0789] K=0.00000e+00 A4=-4.47037e-06 A 6=-6.44026e-08 A 8=2.05905e-10 A10=-6.27518e-13 A12=7.31725e-16

[0790] Surface 14

[0791] K=0.00000e+00 A4=-1.37402e-06 A 6=6.20006e-09 A8=-1.27963e-11 A10=6.01445e-14 A12=-1.20501e-16

[0792] Surface 15

[0793] K=0.00000e+00 A4=-3.44872e-06 A 6=2.97587e-08 A 8=-1.68641e-10 A10=5.42072e-13 A 12=-7.60286e-16

[0794] Various data

[0795]

[0796] Table 1 summarizes the various values ​​in each numerical example.

[0797] Table 1

[0798]

[0799] Reference now Fig.55 , a description will be given of a digital still camera (image pickup device) using the optical system according to any one of the above-described examples as an imaging optical system. Fig.15 An image pickup device 6 having an optical system according to any one of the above-described examples is explained. Fig.15 , reference numeral 4 denotes a camera body, and reference numeral 3 denotes an imaging optical system corresponding to any one of the optical systems OS1 to OS26 according to each example. Reference numeral 5 denotes an image sensor (photoelectric conversion element) such as a CCD sensor or a CMOS sensor, which is built into the camera body 4 and is configured to receive and configured to photoelectrically convert an optical image formed by the imaging optical system 3. The camera body 4 may be a so-called single-lens reflex camera having a quick return mirror, or a so-called mirrorless camera having no quick return mirror.

[0800] The optical system according to each example can be used for imaging cameras and distance detection cameras of smartphones, lens interchangeable type cameras, lens fixed cameras, lens attached films (disposable cameras), etc. It can also be used for line of sight (sight line) detection, biometric recognition, and facial expression recognition in camera viewfinders and XR devices, for example. It can also be used for external recognition applications such as XR devices and autonomous robots.

[0801] Each example can provide an optical system and an image pickup device, each of which has a reduced size and high optical performance in a wide focusing range.

[0802] Although the present disclosure has described example embodiments, it is to be understood that some embodiments are not limited to the disclosed embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An optical system, comprising: a first transflective surface; a second transflective surface, the second transflective surface being located closer to the image than the first transflective surface; as well as a lens located closer to the object than the first transflective surface or closer to the image than the second transflective surface, characterised in that the first transflective surface is configured to move in the direction of the optical axis during focusing, wherein the lens is separated from each of the first transflective surface and the second transflective surface.

2. The optical system according to claim 1, characterized in that The lens is located closest to the object.

3. The optical system according to claim 1, characterized in that The following inequalities are satisfied: in is the refractive power of the portion of the optical system on the object side of the first transflective surface, and is the capability of the optical system.

4. The optical system according to claim 1, characterized in that In the case where the on-axis marginal ray is reflected by the second transflective surface, the following inequality is satisfied: 0.15≤Hm2 / f≤3.00 Wherein Hm2 is the distance from the optical axis to the reflection point in a direction perpendicular to the optical axis, and f is the focal length of the optical system.

5. The optical system according to claim 1, characterized in that the following The inequality is satisfied: 0.0≤dpupil / f≤2.0 Where dpupil is the distance from the surface of the optical system closest to the object to the entrance pupil of the optical system, and f is the focal length of the optical system.

6. The optical system according to claim 1, characterized in that the following The inequality is satisfied: 0.6≤Pm1 / Ppupil≤2.0 Wherein Pm1 is the effective diameter of the first transflective surface, and Ppupil is the entrance pupil diameter of the optical system.

7. The optical system according to claim 1, characterized in that the following The inequality is satisfied: 0.5≤Fno≤2.5 Wherein Fno is the F number of the optical system.

8. The optical system according to claim 1, further comprising a lens disposed on the object side of the first transflective surface, separated from the first transflective surface, and configured to move integrally with the first transflective surface during focusing, Features The following inequalities are satisfied: in is the refractive power of a portion of the optical system on the object side of the lens unit that moves integrally with the first transflective surface during focusing, and is the capability of the optical system.

9. The optical system according to claim 1, characterized in that the following The inequality is satisfied: 0.005≤|Δdf| / f / Fno≤1.000 wherein |Δdf| is the amount of movement during focusing from infinity to a distance corresponding to 10 times the focal length of the optical system, f is the focal length of the optical system, and Fno is the F number of the optical system.

10. The optical system according to claim 1, characterized in that A distance between the first transflective surface and the second transflective surface changes during focusing. 11 . The optical system according to claim 1 , further comprising an aperture stop configured to move integrally with the first transflective surface in an optical axis direction during focusing. 12 . The optical system according to claim 1 , further comprising a lens disposed outside a region between the first transflective surface and the second transflective surface and configured to move in an optical axis direction during focusing.

13. The optical system according to claim 1, characterized in that During focusing, each of the first transflective surface and the second transflective surface is configured not to rotate about the optical axis by 0.5° or more.

14. The optical system according to claim 1, characterized in that The following inequalities are satisfied: 0.0≤|θm|≤8.0 Wherein θm (°) is the smaller of the opening angle of the first transflective surface and the opening angle of the second transflective surface.

15. The optical system according to claim 1, characterized in that At least one of the first transflective surface and the second transflective surface is provided on a joining surface of two light-transmitting members.

16. The optical system according to claim 1, characterized in that At least one of the first transflective surface and the second transflective surface is a spherical surface. 17 . The optical system according to claim 1 , further comprising an image stabilization unit disposed on an object side of the first transflective surface.

18. The optical system according to claim 17, characterized in that the following The inequality is satisfied: 0.6≤β≤1.5 where β is the lateral magnification of the unit deployed on the image side of the second transflective surface.

19. An image pickup device, comprising: An optical system according to any one of claims 1 to 18; as well as Image sensor.

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