Optical system, and imaging device

Abstract

An optical system (1) characterized by comprising, in order from an object side to an image side, a first optical element group (G1), a second optical element group (G2), and a third optical element group (G3), the first optical element group (G1) including a lens group (10) including at least one lens and having a positive refractive power, and a reflecting optical element (15) having a reflecting surface (15a) capable of bending an optical axis, the second optical element group (G2) including at least three lenses (21, 22, 23) and having a negative refractive power, the third optical element group (G3) including at least one lens and having a positive refractive power, when a focal length of the third optical element group (G3) is set as f G3 , and a focal length of the optical system (1) as a whole at the time of focusing at infinity is set as f, the following is satisfied: 3 > f G3 / f > 0.5.

Description

Technical Field

[0001] The present invention relates to an optical system having multiple optical elements, and an imaging apparatus having said optical system. Background Technology

[0002] Previously, various optical systems equipped with reflective optical elements were known.

[0003] For example, the optical system described in CN216956501U includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens with positive refractive power and a prism capable of bending the optical axis. The second lens group includes two lenses, and the third lens group includes one lens. The optical system focuses by moving the third lens group in the direction of the optical axis.

[0004] Furthermore, the optical system described in US9557627B2 includes a first lens group and a second lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens with positive refractive power and a prism capable of bending the optical axis. The second lens group comprises four lenses. This optical system achieves focusing by moving the second lens group along the optical axis. The total optical length (TTL) of this optical system is less than 16 mm, and the focal length is in the range of 8–14 mm.

[0005] Furthermore, the optical system described in US20210048628A1 includes a first lens group and a second lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens with positive refractive power and a prism capable of bending the optical axis. The second lens group contains four lenses. This optical system achieves focusing by moving the second lens group in the optical axis direction. In this optical system, the back focal length (BFL) is large.

[0006] Existing technical documents Patent documents Patent Document 1: CN216956501U Patent Document 2: US9557627B2 Patent document 3: US20210048628A1. Summary of the Invention

[0007] The problem the invention aims to solve The objective of this invention is to provide an optical system that can be configured in a thin shooting device and has a large aperture and is capable of telephoto shooting, as well as a shooting device equipped with the optical system.

[0008] Solution for solving the problem The optical system of the present invention comprises: The first optical element group, the second optical element group, and the third optical element group are arranged sequentially from the object side to the image side. The first optical element group has positive refractive power and can bend the optical axis. The second optical element group contains at least three lenses and has negative refractive power. The third optical element group includes at least one lens and has positive refractive power. When the focal length of the third optical element group is set to f G3 And when the focal length of the entire optical system at infinity is set to f, it satisfies: 3>f G3 / f>0.5.

[0009] In addition, in the optical system, Focusing can also be achieved by moving the third optical element group along the optical axis.

[0010] In addition, in the optical system, The number of lenses in the third optical element group may also be less than the number of lenses in the second optical element group.

[0011] In addition, in the optical system, The lens group can also be configured such that the incident pupil is located within the reflective optical element.

[0012] In addition, in the optical system, The reflective optical element is a prism. When the optical axis before the reflective surface is bent is set as the first optical axis, and the angle of the first optical axis relative to the reflective surface is set as α, the following can be satisfied: 30°≤α≤60°.

[0013] In addition, in the optical system, When the optical axis after the reflective surface is bent is set as the second optical axis, and the maximum effective diameter of the first optical axis when focusing at infinity is set as D1, and the maximum effective diameter of the second optical axis is set as D2, the following can be satisfied: 1 < D1 / D2 < 2.

[0014] In addition, in the optical system, The Abbe number of at least one lens included in the lens group can be 40 or higher.

[0015] In addition, in the optical system, When the focal length of the lens group is set to f1, the following can be satisfied: 1.2 > f1 / f > 0.4.

[0016] In addition, in the optical system, The second optical element group may further include a first lens with negative refractive power, a second lens with positive refractive power, and a third lens with negative refractive power arranged from the object side to the image side.

[0017] In addition, in the optical system, Any lens included in the second optical element group has negative refractive power. The refractive index N of the lens can satisfy: Refractive index N > 1.5.

[0018] In addition, in the optical system, When the distance along the optical axis from the surface of the lens closest to the reflecting optical element in the lens group to the surface of the lens closest to the reflecting optical element in the second group is defined as S1, and the distance along the optical axis from the surface of the object-side lens in the optical system closest to the object to the imaging plane is defined as TTL, the following can be satisfied: 0.5 > S1 / TTL > 0.1.

[0019] In addition, in the optical system, Let F, which is the ratio of the focal length f to the diameter of the entrance pupil, be defined as F. NO When focusing at infinity, the range of the F-value can be: 1.6≤F NO ≤8.

[0020] In addition, in the optical system, When the distance along the optical axis from the object-side surface of the lens closest to the object side of the optical system to the imaging plane is set to TTL, and the effective focal length of the optical system is set to EFL, the following can be satisfied: 1 < TTL / EFL < 1.5.

[0021] In addition, in the optical system, When the distance along the optical axis from the image-side surface of the lens closest to the image side of the optical system at infinity focus to the imaging plane is defined as BFL, and the distance along the optical axis from the object-side surface of the lens closest to the object side of the optical system to the imaging plane is defined as TTL, the following can be satisfied: BFL / TTL≤0.25.

[0022] In addition, in the optical system, The actual focal length of this optical system can be 12mm or more.

[0023] In addition, in the optical system, When the dimension of the optical system in the direction of the extension of the optical axis, i.e., the first optical axis, before being bent by the reflecting surface is set as MH, the following can be satisfied: 5mm≤MH≤13mm.

[0024] In addition, in the optical system, The first optical element group includes: a lens group comprising at least one lens and having positive refractive power, and a reflective optical element having a reflective surface capable of bending the optical axis; or the first optical element group includes an integrally formed optical element consisting of a lens portion having positive refractive power and a prism portion capable of bending the optical axis.

[0025] Furthermore, the imaging device of the present invention includes: Any of the above optical systems; and An image sensor configured at the imaging position of the optical system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram showing the structure of the imaging device in this embodiment.

[0027] Figure 2 This is a schematic diagram showing the structure of the optical system of the imaging device.

[0028] Figure 3 This is a lens structure diagram of the optical system in Example 1.

[0029] Figure 4 This is a longitudinal aberration diagram of the optical system of Example 1 when it is in focus at infinity.

[0030] Figure 5 This is a longitudinal aberration diagram of the optical system of Example 1 at 1000mm focal length.

[0031] Figure 6 This is a lateral aberration diagram of the optical system of Example 1 when it is in focus at infinity.

[0032] Figure 7 This is a lateral aberration diagram of the optical system of Example 1 at 1000mm focal length.

[0033] Figure 8 This is a lens structure diagram of the optical system in Example 2.

[0034] Figure 9 This is a longitudinal aberration diagram of the optical system of Example 2 when it is in focus at infinity.

[0035] Figure 10 This is a longitudinal aberration diagram of the optical system of Example 2 at 1000mm focal length.

[0036] Figure 11 This is a lateral aberration diagram of the optical system of Example 2 when it is in focus at infinity.

[0037] Figure 12 This is a lateral aberration diagram of the optical system of Example 2 at 1000mm focal length.

[0038] Figure 13 This is a lens structure diagram of the optical system in Example 3.

[0039] Figure 14 This is a longitudinal aberration diagram of the optical system of Example 3 when it is in focus at infinity.

[0040] Figure 15 This is a longitudinal aberration diagram of the optical system of Example 3 at 1000mm focal length.

[0041] Figure 16 This is a lateral aberration diagram of the optical system of Example 3 when it is in focus at infinity.

[0042] Figure 17 This is a lateral aberration diagram of the optical system of Example 3 at 1000mm focal length.

[0043] Figure 18 This is a lens structure diagram of the optical system in Example 4.

[0044] Figure 19 This is a longitudinal aberration diagram of the optical system of Example 4 when it is in focus at infinity.

[0045] Figure 20 This is a longitudinal aberration diagram of the optical system of Example 4 at 1000mm focal length.

[0046] Figure 21 This is a lateral aberration diagram of the optical system of Example 4 when it is in focus at infinity.

[0047] Figure 22 This is a lateral aberration diagram of the optical system of Example 4 at 1000mm focal length.

[0048] Figure 23 This is a lens structure diagram of the optical system in Example 5.

[0049] Figure 24 This is a longitudinal aberration diagram of the optical system of Example 5 when it is in focus at infinity.

[0050] Figure 25 This is a longitudinal aberration diagram of the optical system of Example 5 at 1000mm focal length.

[0051] Figure 26This is a lateral aberration diagram of the optical system of Example 5 when it is in focus at infinity.

[0052] Figure 27 This is a lateral aberration diagram of the optical system of Example 5 at 1000mm focal length. Detailed Implementation

[0053] An embodiment of the present invention will now be described with reference to the accompanying drawings.

[0054] The shooting device in this embodiment is a digital camera, smartphone, tablet computer, or other shooting device capable of shooting objects. The shooting device described below is, for example, a smartphone.

[0055] like Figure 1 As shown, the shooting device 100 includes: an optical system 1, at least a portion of which is built into the smartphone body (shooting device body) 101; and an image sensor 5, which is disposed at the imaging position of the optical system 1. Specifically, the shooting device 100 includes a smartphone body 101, an optical system 1, an image sensor 5, and a display unit 102 such as a liquid crystal display screen that displays shooting (image) data output from the image sensor 5.

[0056] The image sensor 5, located at the imaging position of the optical system 1, is a component that converts the optical image formed by the optical system 1 into an electrical signal (imaging data). In this embodiment, the image sensor 5 is a CMOS image sensor. The effective image height IH of the image sensor 5 is half the diagonal length of the image sensor 5, and the frame ratio of the image sensor 5 is 3:4, 9:16, 3:2, etc.

[0057] The optical system 1 includes at least a first optical element group G1, a second optical element group G2, and a third optical element group G3 arranged sequentially along the optical axis C from the object side to the image side. Each of these optical element groups G1, G2, and G3 includes at least one optical element such as a lens. In this embodiment, the optical system 1 includes, along the optical axis C from the object side to the image side, the first optical element group G1, the second optical element group G2, the third optical element group G3, and an optical filter (an IR filter in this embodiment) 6. Furthermore, the optical system 1 includes an aperture (aperture device) 7 disposed at a predetermined position along the optical axis C, and a protective glass 8 disposed on the object side of the first optical element group G1.

[0058] In this optical system 1, during focusing, the distances of the first optical element group G1 and the second optical element group G2 from the image sensor 5 (the imaging surface of the optical system 1) on the optical axis C are fixed, while the third lens group G3 moves along the optical axis C. That is, in the optical system 1 of this embodiment, the third optical element group G3 of each of the optical element groups G1, G2, and G3 constitutes the focusing lens group.

[0059] Furthermore, the movement of the third optical element group G3 during focusing is performed by various mechanisms known in the past. In addition, the image stabilization (hand shake correction) in the optical system 1 can be performed by either sensor displacement or lens displacement (overall displacement of the optical element group or displacement of the third optical element group).

[0060] The following is a detailed description of each optical element group G1 to G3 in optical system 1.

[0061] The first optical element group G1 includes: a lens group 10 containing at least one lens and having positive refractive power; and a reflective optical element 15 having a reflective surface 15a capable of bending the optical axis C. In the first optical element group G1 of this embodiment, the lens group 10 includes a lens 11, and the reflective optical element 15 is a prism made of glass. Furthermore, the second optical element group G2 includes at least three lenses and has negative refractive power. The second optical element group G2 of this embodiment includes three lenses (first lens 21, second lens 22, and third lens 23). Of these three lenses 21, 22, and 23, the first lens 21 has negative refractive power, the second lens 22 has positive refractive power, and the third lens 23 has negative refractive power. Furthermore, the third optical element group G3 includes at least one lens and has positive refractive power. The third optical element group G3 of this embodiment includes a lens 31.

[0062] The optical system 1 of this embodiment includes: a bending portion 10A, which allows light rays (light from an object) to be incident on and bends the optical axis C of the incident light rays; and a main body portion 10B, which is built into the smartphone main body 101. The bending portion 10A is the part where the first optical element group G1 is disposed, and the main body portion 10B is the part where the second optical element group G2 and the third optical element group G3 are disposed. In this optical system 1, the optical axis in the bending portion 10A (i.e., the optical axis before being bent by the reflecting surface 15a) is also referred to as the first optical axis C1, and the optical axis in the main body portion 10B (i.e., the optical axis after being bent by the reflecting surface 15a) is also referred to as the second optical axis C2.

[0063] Furthermore, in the optical system 1 of this embodiment, the lens group 10 and the third optical element group G3 are convenient names, and they also include components consisting of only one optical element (lens, etc.). That is, both the lens group 10 and the third optical element group G3 include at least one optical element such as a lens. In addition, in the optical system 1, optical elements (lenses, etc.) that are fixed in position on the optical axis C during focusing are distinguished from moving optical elements. The fixed at least one optical element in the distinguished area is considered as one lens group, and the moving at least one optical element in the distinguished area is considered as another lens group.

[0064] Here, the focal length of the third optical element group G3 is set to f. G3 When the focal length of the optical system 1 as a whole when it is focused at infinity is set to f, the optical system 1 can satisfy the following formula (1).

[0065] 3>f G3 / f>0.5…(1) Thus, by satisfying the above formula (1) in optical system 1, an optical system with a large aperture and capable of telephoto shooting (the so-called large-aperture telephoto lens) is obtained, that is, an optical system that performs rear focusing. Telephoto shooting can be performed using optical system 1.

[0066] In optical system 1, at this ratio (f) G3 When the ratio (f / f) is 3 or higher, the optical power of the third optical element group G3 weakens, and the focusing stroke increases. On the other hand, in optical system 1, when this ratio (f / f) is 3 or higher, the optical power of the third optical element group G3 weakens, and the focusing stroke increases. G3 When / f) is below 0.5, the optical power of the third optical element group G3 becomes too strong, making it impossible to achieve the overall optical power balance of optical system 1 (multiple optical element groups G1, G2, G3), and reducing the performance of high viewing angle.

[0067] Furthermore, from the viewpoint of focusing stroke and the optical power configuration of each optical element group G1, G2, G3, it is more preferable that the optical system 1 satisfies the following formula (2).

[0068] 2.5 > f G3 / f>0.8…(2) Furthermore, in this optical system 1, focusing can also be achieved by moving the third optical element group G3 along the optical axis C. Thus, by configuring a portion (the third optical element group) G3 of the plurality of optical elements 21, 22, 23, 31 disposed in the main body portion (the portion closer to the image side than the prism 15) 1B of the optical system 1 to perform focusing in the direction of the second optical axis C2 (the direction of the optical axis after being bent by the reflecting surface 15a), it is possible to suppress the movement of the optical element (in this embodiment, a lens) 31 in the direction of the second optical axis C2 (…). Figure 2 The mechanism that moves in the vertical direction (in the middle) can reduce loads and vibrations during operation, and can simplify and miniaturize the mechanism, thereby appropriately suppressing the loads on the main body 10B in the first optical axis C1 direction (in the middle). Figure 2 The dimensions in the left and right directions.

[0069] Furthermore, in this optical system 1, the number of lenses 31 included in the third optical element group g1 can be smaller than the number of lenses 21, 22, and 23 included in the second optical element group G2. This further suppresses the load on the mechanism driving the third optical element group G3 in the second optical axis C2 direction, vibrations during driving, and further simplifies and miniaturizes the mechanism, thereby further suppressing the size of the main body 10B in the first optical axis C1 direction.

[0070] Furthermore, in this optical system 1, the lens group 10 of the first optical element group G1 can also be configured such that the entrance pupil is located within the prism 15. This further reduces the overall optical length of the optical system 1.

[0071] In addition, in this optical system 1, the reflective optical element of the first optical element group G1 is a prism 15. When the optical axis before being bent by the reflective surface 15a of the prism 15 is set as the first optical axis C1, and the angle of the first optical axis C1 relative to the reflective surface 15a is set as α, the optical system 1 can satisfy the following formula (3).

[0072] 30°≤α≤60°…(3) Thus, by satisfying the above formula (3) in the optical system 1, the size of the optical system 1 in the direction of the first optical axis C1 can be suppressed. In this embodiment, the angle α in the optical system 1 is 45°.

[0073] In addition, in this optical system 1, When the optical axis C after the reflective surface 15a is bent is set as the second optical axis C2, the maximum effective diameter of the first optical axis C1 when focusing at infinity is set as D1, and the maximum effective diameter of the second optical axis C2 is set as D2, the optical system 1 can satisfy the following formula (4).

[0074] 1 < D1 / D2 < 2… (4) Thus, by satisfying the above formula (4) in the optical system 1, the size of the main body 10B of the optical system 1 in the direction of the first optical axis C1 can be sufficiently reduced. As a result, the optical system 1 (i.e., a large-aperture telephoto lens) can be configured in a thin shooting device 100 such as a smartphone with the main body 10B built in.

[0075] Furthermore, the maximum effective diameter D1 located on the first optical axis C1 is more specifically the maximum effective diameter of the light rays passing through lens 11, and the maximum effective diameter D2 located on the second optical axis C2 is more specifically the maximum effective diameter of the light rays passing through lens 21, which is closest to the object side in the second optical element group G2. Additionally, in the optical system 2 of this embodiment, the optimal value of D1 / D2 is approximately 1.6.

[0076] Furthermore, in this optical system 1, the Abbe number of at least one lens 11 included in the lens group 10 of the first optical element group G1 can be 40 or more.

[0077] Thus, in the lens group (the group of optical elements closer to the object side than the prism 15) 10, which has the optical power that best converges the light beam and has a dominant influence on spherical aberration and on-axis chromatic aberration in the optical system 1, at least one lens 11 is made of a low dispersion material with an Abbe number of 40 or more, thereby reducing the overall chromatic aberration of the optical system 1.

[0078] In addition, in this optical system 1, when the focal length of the lens group 10 is set to f1, the optical system 1 can satisfy the following formula (5).

[0079] 1.2>f1 / f>0.4…(5) In optical system 1, when the ratio (f1 / f) is 1.2 or higher, the optical power of lens group 10 decreases, thus increasing the overall optical length of optical system 1. On the other hand, when the ratio (f1 / f) is 0.4 or lower, the optical power of lens group 10 increases, thus decreasing the overall optical length of optical system 1, making it impossible to ensure the proper spacing for arranging prism 15 between lens group 10 and second optical element group G2. Furthermore, spherical aberration also increases. That is, according to the above configuration, it is possible to suppress both the overall optical length and spherical aberration while ensuring the proper placement space for prism 15.

[0080] Furthermore, more preferably, the ratio of the focal length f1 of the lens group 10 to the focal length f of the entire optical system 1 when it is focused at infinity satisfies the following formula (6).

[0081] 1.1>f1 / f>0.5…(6) Furthermore, in this optical system 1, the second optical element group G2 may include a first lens 21 with negative refractive power, a second lens 22 with positive refractive power, and a third lens 23 with negative refractive power, arranged from the object side to the image side. Thus, the second optical element group G2 in the optical system 1 can correct various aberrations, resulting in an appropriate reduction of spherical aberration and off-axis aberration in the optical system 1. Additionally, other lenses can be arranged between any of the lenses while the lenses 21, 22, and 23 are arranged sequentially from the object side to the image side.

[0082] In addition, in this optical system 1, any one of the lenses 21 and 23 included in the second optical element group G2 has negative refractive power, and the refractive index N of the lens 21 and 23 can satisfy the following formula (7).

[0083] Refractive index N > 1.5…(7) In optical system 1, the Petzval sum can be reduced by satisfying formula (7). Furthermore, the Petzval sum is expressed by the following formula (8).

[0084] P = ∑(1 / Nf) … (8) In addition, in this optical system 1, When the distance along the optical axis from the surface of the lens closest to the reflecting optical element in the lens group to the surface of the lens closest to the reflecting optical element in the second group is defined as S1, and the distance along the optical axis from the surface of the lens closest to the object in the optical system to the imaging plane is defined as TTL, the optical system 1 can satisfy the following formula (9). Furthermore, the aforementioned "TTL" is... Figure 2 The total distance between TL1 and TL2 shown above, where "S1" is... Figure 2 The total distance between tp1 and tp2 is shown.

[0085] 0.5 > S1 / TTL > 0.1…(9) Thus, by satisfying the above formula (9) in the optical system 1, the arrangement space of the reflective optical element 15 in the optical path of the optical system 1 can be ensured, thereby enabling the optical system 1 to be configured in a way that allows the optical axis C to be bent at the desired angle and the effective light rays to not be cut off.

[0086] In addition, in this optical system 1, Let F, which is the ratio of focal length f to the diameter of the entrance pupil, be defined as F. NO When the focus is achieved at infinity, the range of F-values ​​can satisfy the following formula (10).

[0087] It can be 1.6≤F NO ≤8…(10).

[0088] Thus, by satisfying the above formula (10) in the optical system 1, the maximum lens entrance pupil diameter can be achieved within the constraints of the external dimensions of the optical system 1, thereby improving the image quality of the imaging device 100 equipped with the optical system 1.

[0089] Furthermore, in this optical system 1, when the distance along the optical axis C from the object-side surface of the lens 11 closest to the object side of the optical system 1 to the imaging surface is set to TTL, and the effective focal length of the optical system 1 is set to EFL, the optical system 1 can satisfy the following formula (11).

[0090] It can satisfy: 1 < TTL / EFL < 1.5... Equation (11).

[0091] Thus, by satisfying the above formula (11) in optical system 1, a balance between the optical performance and the external dimensions of optical system 1 is achieved. That is, in optical system 1, when the ratio (TTL / EFL) is 1.5 or higher, the length (length along the optical axis C) of optical system 1 becomes too large, and when it is less than 1, the performance of optical system 1 decreases.

[0092] Furthermore, in this optical system 1, the distance along the optical axis C from the image-side surface of the lens 11 closest to the image side when focusing from infinity to the imaging plane is defined as BFL (refer to...). Figure 2 When the distance along the optical axis C from the object-side surface of the lens 11 closest to the object side of the optical system 1 to the imaging surface is set to TTL, the optical system 1 can satisfy the following formula (12).

[0093] It can satisfy: BFL / TTL≤0.25…(12).

[0094] Thus, by satisfying the above formula (12) in the optical system 1, the lens closest to the image side can be positioned closer to the imaging plane, thereby ensuring that the lens closest to the image side can be used as a space for the focusing group to move in the direction of the optical axis (second optical axis C2).

[0095] In addition, the optical system 1 is characterized in that its actual focal length is 12mm or more.

[0096] Furthermore, in the optical system described above, when the dimension of the optical system 1 in the direction of the extension of the optical axis C, i.e., the first optical axis C1, before being bent by the reflecting surface 15a of the prism 15 is set as MH (refer to...), Figure 2 Optical system 1 can satisfy the following formula (13).

[0097] 5mm≤MH≤13mm…(13) Thus, by satisfying the above formula (13) in the optical system 1, an optical system 1 with a sufficiently small size in the first optical axis C1 direction can be obtained. As a result, it is also possible to achieve a thinner (miniaturized) smartphone (shooting device) 100 equipped with this optical system 1.

[0098] According to the optical system 1 described above, by bending the optical axis C using the prism 15, the dimension in the direction of the first optical axis C1 can be suppressed. Furthermore, according to this optical system 1, a telephoto lens with a large aperture (i.e., a small F-number) is obtained. For example, the optical system 1 of this embodiment can perform telephoto shooting with an aperture (F-number of approximately 2) larger than the thickness (dimension in the direction of the first optical axis C1) of the smartphone body 101, equivalent to 125mm. In addition, by having a large aperture (i.e., a small F-number) optical system 1, the dynamic range of the smartphone (shooting device) 100 is improved. Moreover, by configuring a portion (the third optical element group) G3 of the multiple optical element groups G1, G2, and G3 included in the optical system 2 to move along the optical axis for focusing, aberration variations are suppressed.

[0099] Furthermore, by arranging the optical system 1 in a manner that incorporates the main body 10B, it is possible to achieve a thinner smartphone (shooting device) 100 (miniaturization of its size in the direction of the first optical axis C1).

[0100] Furthermore, the optical system 1 and the imaging device 100 equipped with the optical system 1 of the present invention are not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. For example, by adding the configuration of another embodiment to the configuration of one embodiment, or by replacing a part of the configuration of one embodiment with the configuration of another embodiment, or by deleting a part of the configuration of one embodiment.

[0101] In the optical system 1 of this embodiment, the lens group 10 of the first optical element group G1 includes one lens 11, but is not limited to this configuration. The lens group 10 may also include two or more lenses. According to this configuration, it is easier to suppress various aberrations. Moreover, since the bent portion 10A on which the first optical element group G1 is disposed is a part of which protrudes from the smartphone body 101, and the main body portion 10B built into the smartphone body 101 has the same dimension in the first optical axis C1 direction, the thickness dimension (dimension in the first optical axis C1 direction) of the smartphone body 101 can be maintained without increasing it.

[0102] Next, embodiments 1 to 5 of the imaging apparatus of the present invention will be described. In the following embodiments, the same reference numerals are used for structures corresponding to the optical systems of the above embodiments. Furthermore, in the tables of the following embodiments, r is the radius of curvature, d is the lens thickness or lens spacing, nd is the refractive index of the d-line, and vd represents the Abbe number based on the d-line. Additionally, an aspherical surface is defined, for example, by Formula 1 shown below.

[0103] Formula 1

[0104] (Where, c is the curvature (1 / r), h is the height (distance) from the optical axis, k is the conic coefficient, and A4, A6, A8, A10... are the aspheric coefficients of each order.) In addition, the longitudinal aberration diagrams, from left to right, show spherical aberration (mm), astigmatism (mm), and distortion aberration (DIS (%)). In the spherical aberration diagram, solid lines represent the characteristics of the d-line, short dashed lines represent the characteristics of the F-line, and long dashed lines represent the characteristics of the C-line. In the astigmatism diagram, the vertical axis represents the maximum image height; solid lines represent the characteristics of the sagittal plane (represented by X in the diagram), and dashed lines represent the characteristics of the meridional plane (represented by Y in the diagram). In the distortion aberration diagram, the vertical axis represents the maximum image height.

[0105] Next, embodiments 1 to 5 of the present invention will be described. First, after showing various data for each embodiment in Table 1, each embodiment will be described in detail.

[0106] Table 1

[0107] Example 1 Figure 3 This is a lens structure diagram of the optical system 1A in this embodiment 1. Figure 4 It is the longitudinal aberration map when the image is in focus at infinity. Figure 5 This is a longitudinal aberration diagram at 1000mm focus. Figure 6 It is a lateral aberration map when the image is in focus at infinity. Figure 7 This is a lateral aberration diagram at 1000mm focus. Additionally, Table 2 below shows the surface data for each lens, Table 3 shows the aspherical surface data, Table 4 shows the eccentricity data for the reflecting surface, and Table 5 shows the position data during focusing.

[0108] The optical system 1A of this embodiment 1 includes, arranged sequentially from the object side to the image side, a lens 11A with positive refractive power, a prism 15, an aperture 7, a lens 21A with negative refractive power, a lens 22A with positive refractive power, a lens 23A with positive refractive power, a lens 24A with negative refractive power, and a lens 31A with positive refractive power. In this optical system 1A, the second optical element group G2 has negative refractive power and includes lenses 21A, 22A, 23A, and 24A. The refractive powers of lenses 21A, 22A, 23A, and 24A in the second optical element group G2 are arranged in the order of negative, positive, positive, and negative. Furthermore, the third optical element group G3 includes lens 31A, which is focused by moving along the second optical axis C2.

[0109] Table 2

[0110] Table 3

[0111] Table 4

[0112] Table 5

[0113] Table 6

[0114] Example 2 Figure 8 This is a lens structure diagram of the optical system 1B in this embodiment 2. Figure 9 It is the longitudinal aberration map when the image is in focus at infinity. Figure 10 This is a longitudinal aberration diagram at 1000mm focus. Figure 11 It is a lateral aberration map when the image is in focus at infinity. Figure 12 This is a lateral aberration diagram at 1000mm focus. Additionally, Table 7 below shows various data, Table 8 shows the surface data for each lens, Table 9 shows the aspherical surface data, Table 10 shows the eccentricity data for the reflecting surface, and Table 11 shows the position data during focusing.

[0115] The optical system 1B of this embodiment 2 includes, from the object side to the image side, a lens 11B with positive refractive power, a prism 15, an aperture 7, a lens 21B with negative refractive power, a lens 22B with positive refractive power, a lens 23B with negative refractive power, a lens 24B with negative refractive power, and a lens 31B with positive refractive power. In this optical system 1B, the second optical element group G2 has negative refractive power and includes lenses 21B, 22B, 23B, and 24B. The refractive powers of lenses 21B, 22B, 23B, and 24B in the second optical element group G2 are arranged in the order of negative, positive, negative, and negative. Furthermore, the third optical element group G3 includes lens 31B, which is focused by moving along the second optical axis C2.

[0116] Table 7

[0117] Table 8

[0118] Table 9

[0119] Table 10

[0120] Table 11

[0121] Example 3 Figure 13 This is a lens structure diagram of the optical system 1C in this embodiment 3. Figure 14 It is the longitudinal aberration map when the image is in focus at infinity. Figure 15 This is a longitudinal aberration diagram at 1000mm focus. Figure 16 It is a lateral aberration map when the image is in focus at infinity. Figure 17 This is a lateral aberration diagram at 1000mm focus. Additionally, Table 12 below shows various data, Table 13 shows the surface data for each lens, Table 14 shows the aspherical surface data, Table 15 shows the eccentricity data for the reflecting surface, and Table 16 shows the position data during focusing.

[0122] The optical system 1C of this embodiment includes, arranged sequentially from the object side to the image side, a prism 15A (an optical element integrally formed with a lens 11C having positive refractive power and the prism 15A) with a convex surface on the object side, a lens 21C having negative refractive power, an aperture 7, a lens 22C having positive refractive power, a lens 23C having negative refractive power, and a lens 31C having positive refractive power. In this optical system 1C, the second optical element group G2 has negative refractive power and includes lenses 21C, 22C, and 23C. The refractive powers of lenses 21C, 22C, and 23C in the second optical element group G2 are arranged in the order of negative, positive, and negative. In addition, the third optical element group G3 includes lens 31C, which is focused by moving along the second optical axis C2.

[0123] Table 12

[0124] Table 13

[0125] Table 14

[0126] Table 15

[0127] Table 16

[0128] Example 4 Figure 18 This is a lens structure diagram of the optical system 1D in Embodiment 4. Figure 19 It is the longitudinal aberration map when the image is in focus at infinity. Figure 20 This is a longitudinal aberration diagram at 1000mm focus. Figure 21 It is a lateral aberration map when the image is in focus at infinity. Figure 22 This is a lateral aberration diagram at 1000mm focus. Additionally, Table 17 below shows various data, Table 18 shows the surface data for each lens, Table 19 shows the aspherical surface data, Table 20 shows the eccentricity data for the reflecting surface, and Table 21 shows the position data during focusing.

[0129] The optical system 1D of this embodiment 4 includes, from the object side to the image side, a lens 11D with positive refractive power, a prism 15, an aperture 7, a lens 21D with negative refractive power, a lens 22D with positive refractive power, a lens 23D with negative refractive power, a lens 24D with positive refractive power, and a lens 31D with positive refractive power. In this optical system 1D, the second optical element group G2 has negative refractive power and includes lenses 21D, 22D, 23D, and 24D. The refractive powers of lenses 21D, 22D, 23D, and 24D in the second optical element group G2 are arranged in the order of negative, positive, negative, and positive. In addition, the third optical element group G3 includes lens 31D, which is focused by moving along the second optical axis C2.

[0130] Table 17

[0131] Table 18

[0132] Table 19

[0133] Table 20

[0134] Table 21

[0135] Example 5 Figure 23 This is a lens structure diagram of the optical system 1E in this embodiment 5. Figure 24 It is the longitudinal aberration map when the image is in focus at infinity. Figure 25 This is a longitudinal aberration diagram at 1000mm focus. Figure 26 It is a lateral aberration map when the image is in focus at infinity. Figure 27 This is a lateral aberration diagram at 1000mm focus. Additionally, Table 22 below shows various data, Table 23 shows the surface data for each lens, Table 24 shows the aspherical surface data, Table 25 shows the eccentricity data for the reflecting surface, and Table 26 shows the position data during focusing.

[0136] The optical system 1E of this embodiment 5 includes, arranged sequentially from the object side to the image side, a lens 11E with positive refractive power, a prism 15, an aperture 7, a lens 21E with negative refractive power, a lens 22E with positive refractive power, a lens 23E with negative refractive power, a lens 24E with negative refractive power, and a lens 31E with positive refractive power. In this optical system 1E, the second optical element group G2 has negative refractive power and includes lenses 21E, 22E, 23E, and 24E. The refractive powers of lenses 21E, 22E, 23E, and 24E in the second optical element group G2 are arranged in the order of negative, positive, negative, and negative. Furthermore, the third optical element group G3 includes lens 31E, which is focused by moving along the second optical axis C2.

[0137] Table 22

[0138] Table 23

[0139] Table 24

[0140] Table 25

[0141] Table 26

[0142] Although the invention has been adequately and sufficiently described above with reference to the accompanying drawings for the purpose of illustrating the invention, those skilled in the art should recognize that modifications and / or improvements to the above-described embodiments are readily achievable. Therefore, any modifications or improvements implemented by those skilled in the art that do not depart from the scope of the claims can be interpreted as being included within the scope of the claims.

[0143] Explanation of reference numerals in the attached figures: 1, 1A, 1B, 1C, 1D, 1E: Optical systems 10A: Bending section 10B: Main body 5: Image sensor 6: Optical filters 7: Aperture stop 8: Protective Glass 10: Lens Group 11, 11A, 11B, 11C, 11D, 11E: Lenses 15: Prism (reflective optical element) 15a: Reflective surface 21, 21A, 21B, 21C, 21D, 21E: First lens (optical element) 22, 22A, 22B, 22C, 22D, 22E: Second lens (optical element) 23, 23A, 23B, 23C, 23D, 23E: Third lens (optical element) 24A, 24D, 24E: Fourth lens (optical element) 31: Lens (optical element) 100: Filming device 101: Smartphone Body 102: Display Section C: Optical axis C1: First optical axis C2: Second optical axis G1: First Optical Component Group G2: Second optical element group G3: Third optical element group.

Claims

1. An optical system, characterized in that, The optical system consists of a first group of optical elements, a second group of optical elements, and a third group of optical elements arranged sequentially from the object side to the image side. The first optical element group has positive refractive power and is capable of bending the optical axis. The first optical element group comprises: a lens group consisting of a single lens and having positive refractive power, and a reflective optical element having a reflective surface capable of bending the optical axis; or the first optical element group comprises an integrally formed optical element, wherein the optical element consists of a lens portion having positive refractive power and a prism portion capable of bending the optical axis, wherein the lens portion consists of a single lens. The second optical element group has negative refractive power and is composed of a first lens with negative refractive power, a second lens with positive refractive power, and a third lens with negative refractive power arranged from the object side to the image side, or it is composed of a first lens with negative refractive power, a second lens with positive refractive power, a third lens, and a fourth lens arranged from the object side to the image side. The third optical element group consists of a lens and has positive refractive power. When the focal length of the third optical element group is set to f G3 And when the focal length of the entire optical system at infinity is set to f, the following condition is met: 3>f G3 / f>0.5。 2. The optical system according to claim 1, characterized in that, The third optical element group focuses by moving along the optical axis.

3. The optical system according to claim 1 or 2, characterized in that, The lens group is configured such that the incident pupil is located within the reflective optical element.

4. The optical system according to claim 1 or 2, characterized in that, The reflective optical element is a prism. When the optical axis before the reflective surface is bent is defined as the first optical axis, and the angle of the first optical axis relative to the reflective surface is defined as α, the following conditions are met: 30°≤α≤60°。 5. The optical system according to claim 4, characterized in that, When the optical axis after the reflective surface is bent is set as the second optical axis, and the maximum effective diameter of the first optical axis when focusing at infinity is set as D1, and the maximum effective diameter of the second optical axis is set as D2, the following conditions are met: 1 < D1 / D2 < 2.

6. The optical system according to claim 1 or 2, characterized in that, The Abbe number of one of the lenses constituting the lens group is 40 or more.

7. The optical system according to claim 1 or 2, characterized in that, When the focal length of the lens group is set to f1, the following conditions are met: 1.2 > f1 / f > 0.

4.

8. The optical system according to claim 1 or 2, characterized in that, In the second optical element group, any lens other than the second lens has negative refractive power. The refractive index N of the lens satisfies: Refractive index N > 1.

5.

9. The optical system according to claim 1 or 2, characterized in that, When the distance along the optical axis from the surface of the lens closest to the reflecting optical element in the lens group to the surface of the lens closest to the reflecting optical element in the second optical element group is defined as S1, and the distance along the optical axis from the surface of the lens closest to the object in the optical system to the imaging plane is defined as TTL, the following conditions are met: 0.5 > S1 / TTL > 0.

1.

10. The optical system according to claim 1 or 2, characterized in that, Let F be the value of the ratio of the focal length f to the diameter of the incident pupil when the optical system as a whole is focused at infinity. NO When the image is focused at infinity, the range of the F-values ​​satisfies: 1.6≤F NO ≤8。 11. The optical system according to claim 1 or 2, characterized in that, When the distance along the optical axis from the object-side surface of the lens closest to the object side of the optical system to the imaging plane is set to TTL, and the effective focal length of the optical system is set to EFL, the following conditions are met: 1 < TTL / EFL < 1.

5.

12. The optical system according to claim 1 or 2, characterized in that, When the distance along the optical axis from the image-side surface of the lens closest to the image side of the optical system at infinity focus to the imaging plane is defined as BFL, and the distance along the optical axis from the object-side surface of the lens closest to the object side of the optical system to the imaging plane is defined as TTL, the following conditions are met: BFL / TTL≤0.

25.

13. The optical system according to claim 1 or 2, characterized in that, The actual focal length of this optical system is over 12mm.

14. The optical system according to claim 1 or 2, characterized in that, When the dimension of the optical system in the direction of the extension of the optical axis, i.e., the first optical axis, before being bent by the reflecting surface is set as MH, the following condition is satisfied: 5mm≤MH≤13mm.

15. A shooting device, characterized in that, have: The optical system according to any one of claims 1 to 14; and An image sensor configured at the imaging position of the optical system.

Images