Optical system and image pickup device including the same

Abstract

The present disclosure provides an optical system and an image pickup device including the same, belonging to the technical field of optical imaging. The optical system includes an aperture, a first super lens, a second super lens, a first aspheric mirror, and a second aspheric mirror. Along the incident light path, the aperture is located on the first surface of the optical system; the second aspheric mirror is the last lens in the optical system; the first super lens is disposed between the aperture and the second super lens, and the first aspheric mirror is disposed between the aperture and the second aspheric mirror; and at least the following conditions are satisfied: f a1 >0;f a2 <0; f is the effective focal length of the optical system, f a1 is the focal length of the first aspheric mirror, f a2 is the focal length of the second aspherical mirror. This optical system achieves miniaturization.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical imaging, and in particular, to an optical system and an image pickup device comprising the same. Background Art

[0002] The imaging performance of an image pickup device is an important criterion for reflecting its value. Optimizing the number, size, and imaging quality of its lenses is also one of the important goals that major manufacturers are competing to develop.

[0003] In traditional image pickup devices, optical systems typically utilize lenses made of organic materials (e.g., plastic), which have poor environmental resistance and significant temperature fluctuations in refractive index. Consequently, the range of selectable refractive indices and Abbe numbers is limited during optical system design, and field curvature and distortion are prone to occur. Furthermore, conventional lenses (e.g., glass) are generally too thick, making it difficult to reduce the overall size of the optical system. Summary of the Invention

[0004] To solve the above problems, the purpose of the embodiments of the present disclosure is to provide an optical system and image pickup device that reduces the number of lenses used, has a smaller system volume and lower manufacturing cost, while meeting the imaging standards of current mainstream camera equipment.

[0005] According to a first aspect of the present invention, there is provided an optical system comprising an aperture, a first super lens, a second super lens, a first aspherical mirror, and a second aspherical mirror;

[0006] Along the incident light path, the aperture is located on the first surface of the optical system; the second aspheric mirror is the last lens in the optical system; the first metalens is arranged at any position between the aperture and the second metalens, and the first aspheric mirror is arranged at any position between the aperture and the second aspheric mirror;

[0007] Furthermore, the optical system satisfies at least the following conditional expressions:

[0008] f a1 >0;

[0009] f a2 <0;

[0010]

[0011] Where f is the effective focal length of the optical system, f a1 is the focal length of the first aspheric mirror, f a2 is the focal length of the second aspherical mirror.

[0012] In one possible implementation, the optical system satisfies the following conditional expression:

[0013]

[0014] Among them, f m1 is the focal length of the first superlens (10).

[0015] In one possible implementation, the optical system satisfies the following conditional expression:

[0016]

[0017] Among them, f m2 is the focal length of the second superlens (20).

[0018] In one possible implementation, the optical system satisfies the following conditional expression:

[0019] 1.20mm≤max(d a1 ,d a2 )≤1.42mm;

[0020] min(d a1 ,d a2 )<1mm;

[0021] where d a1 is the thickness of the first aspheric mirror, d a2 is the thickness of the second aspherical mirror.

[0022] In one possible implementation, the optical system satisfies the following conditional expression:

[0023] max(n m1 ,n m2 )<1.5≤min(n a1 ,n a2 );

[0024] where n m1 is the refractive index of the first metalens, n m2 is the refractive index of the second metalens, n a1 is the refractive index of the first aspheric mirror, n a2 is the refractive index of the second aspherical mirror.

[0025] In a possible implementation, the surface shapes of the first aspheric mirror and the second aspheric mirror are even-order aspheric surfaces.

[0026] In one possible implementation, the object-side surface of the first aspherical mirror is concave, and the image-side surface of the first aspherical mirror is convex.

[0027] In one possible implementation, the object-side surface of the second aspherical mirror is concave, and the image-side surface of the second aspherical mirror is concave.

[0028] In a possible implementation, along the incident light path, the optical system sequentially includes an aperture, a first super lens, a second super lens, a first aspheric mirror, and a second aspheric mirror.

[0029] In a possible implementation, along the incident light path, the optical system sequentially includes an aperture, a first superlens, a first aspheric mirror, a second superlens, and a second aspheric mirror.

[0030] In a possible implementation, along the incident light path, the optical system sequentially includes an aperture, a first aspheric mirror, a first super lens, a second super lens, and a second aspheric mirror.

[0031] According to another aspect of the present invention, an image pickup device is provided, comprising the optical system provided in any one of the above embodiments and an image sensing device, wherein the image sensing device is configured to receive an image generated by the optical system.

[0032] The optical system provided by the embodiment of the present application and the optical system including the same are made to satisfy the following conditional formula f by making the first super lens, the second super lens, the first aspheric mirror and the second aspheric mirror satisfy the following conditional formula f a1 >0;f a2 <0; This allows the optical system to use fewer lenses and achieve a smaller size while still meeting current imaging standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 shows a cross-sectional schematic diagram of the optical system provided by Example 1 of the present disclosure;

[0035] Figure 2 shows an MTF curve diagram of the optical system provided by Example 1 of the present disclosure;

[0036] Figure 3 Graphs showing field curvature and distortion of the optical system provided by Example 1 of the present disclosure are shown;

[0037] Figure 4 shows an axial aberration diagram of the optical system provided by Example 1 of the present disclosure;

[0038] Figure 5 shows a cross-sectional schematic diagram of an optical system provided by Example 2 of the present disclosure;

[0039] Figure 6 shows an MTF curve diagram of the optical system provided by Example 2 of the present disclosure;

[0040] Figure 7 shows the field curvature and distortion diagram of the optical system provided by Example 2 of the present disclosure;

[0041] Figure 8 shows an axial aberration diagram of the optical system provided by Example 2 of the present disclosure;

[0042] Figure 9 shows a cross-sectional schematic diagram of the optical system provided by Example 3 of the present disclosure;

[0043] Figure 10 shows an MTF curve diagram of the optical system provided by Example 3 of the present disclosure;

[0044] Figure 11 shows the field curvature and distortion diagram of the optical system provided by Example 3 of the present disclosure;

[0045] Figure 12 shows an axial aberration diagram of the optical system provided by Example 3 of the present disclosure;

[0046] Figure 13 shows a cross-sectional schematic diagram of an optical system provided by Example 4 of the present disclosure;

[0047] Figure 14 shows an MTF curve diagram of the optical system provided by Example 4 of the present disclosure;

[0048] Figure 15 shows the field curvature and distortion diagram of the optical system provided by Example 4 of the present disclosure;

[0049] Figure 16 shows an axial aberration diagram of the optical system provided by Example 4 of the present disclosure;

[0050] Figure 17 shows a cross-sectional schematic diagram of the optical system provided by Example 5 of the present disclosure;

[0051] Figure 18 shows an MTF curve diagram of the optical system provided by Example 5 of the present disclosure;

[0052] Figure 19 shows the field curvature and distortion diagram of the optical system provided by Example 5 of the present disclosure;

[0053] Figure 20 shows an axial aberration diagram of the optical system provided by Example 5 of the present disclosure;

[0054] Figure 21 shows a cross-sectional schematic diagram of the optical system provided by Example 6 of the present disclosure;

[0055] Figure 22 shows an MTF curve diagram of the optical system provided by Example 6 of the present disclosure;

[0056] Figure 23 Graphs showing field curvature and distortion of the optical system provided by Example 6 of the present disclosure are shown;

[0057] Figure 24 shows an axial aberration diagram of the optical system provided by Example 6 of the present disclosure;

[0058] Figure 25 shows a cross-sectional schematic diagram of an optical system provided by Example 7 of the present disclosure;

[0059] Figure 26 shows an MTF curve diagram of the optical system provided by Example 7 of the present disclosure;

[0060] Figure 27 Graphs showing field curvature and distortion of the optical system provided by Example 7 of the present disclosure are shown;

[0061] Figure 28 A diagram showing the axial aberration of the optical system provided in Example 7 of the present disclosure is shown.

[0062] List of reference numerals:

[0063] 10-first super lens; 20-second super lens; 30-first aspheric mirror; 40-second aspheric mirror; 50-filter; 60-aperture. DETAILED DESCRIPTION

[0064] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the present disclosure, "plurality" means two or more, unless otherwise specifically defined.

[0066] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0067] In the prior art, aspherical lenses are usually used to form a multi-lens optical imaging module. However, the use of multiple lenses increases the cost of the imaging system on the one hand, and increases the difficulty of manufacturing the imaging system on the other hand.

[0068] In view of this, this embodiment provides an optical system, see Figure 1 , wherein in the cross-sectional schematic diagram of the optical system along the optical axis according to various embodiments, the left side is the object side (magnification side) and the right side is the image side (reduction side). The optical system has an aperture 60 and a plurality of lenses, including a first super lens 10, a second super lens 20, a first aspheric mirror 30, and a second aspheric mirror 40. Among them, along the incident light path, the aperture 60 is located on the first surface on the object side of the optical system; the second aspheric mirror is the last lens in the optical system; the first super lens 10 is set at any position between the aperture 60 and the second super lens 20, and the first aspheric mirror 30 is set at any position between the aperture 60 and the second aspheric mirror 40. Hereinafter, the first super lens 10 and the second super lens 20 are collectively referred to as super lenses, and the first aspheric mirror 30 and the second aspheric mirror 40 are collectively referred to as aspheric mirrors.

[0069] Alternatively, as Figure 1 、 Figure 5 、 Figure 25 As shown, the optical systems according to Examples 1, 2 and 7 are provided with a first super lens 10, a first aspheric mirror 30, a second super lens 20 and a second aspheric mirror 40 in sequence from the object side to the image side.

[0070] Alternatively, as Figure 13 、 Figure 17As shown, the optical systems according to Examples 4 and 6 are provided with a first super lens 10, a second super lens 20, a first aspheric mirror 30, and a second aspheric mirror 40 in sequence from the object side to the image side.

[0071] Alternatively, as Figure 9 、 Figure 21 As shown, the optical systems according to Examples 3 and 5 are provided with a first aspherical mirror 30, a first super lens 10, a second super lens 20, and a second aspherical mirror 40 in sequence from the object side to the image side.

[0072] The optical system according to each embodiment satisfies the following conditional expression:

[0073] f a1 >0 (1);

[0074] f a2 <0 (2);

[0075]

[0076] Where f is the effective focal length of the optical system, f a1 is the focal length of the first aspherical mirror 30, f a2 is the focal length of the second aspherical mirror 40.

[0077] Conditional expression (1) relates to the focal length of the first aspherical mirror 30, which ensures that the optical power of the first aspherical mirror 30 is positive. Optionally, in the embodiment of the present application and various alternative embodiments, the object side surface of the first aspherical mirror 30 is concave and the image side surface is convex.

[0078] Conditional expression (2) relates to the focal length of the second aspherical mirror 40. This focal length ensures that the optical power of the second aspherical mirror 40 is negative, so that the second aspherical mirror 40 and the first aspherical mirror 30 form separate positive and negative lenses, thereby eliminating field curvature of the system. Optionally, in this embodiment and various alternative embodiments, the object-side surface and the image-side surface of the second aspherical mirror 40 are concave.

[0079] Conditional expression (3) relates to the ratio of the focal length of the first aspherical mirror 30 to the effective focal length of the optical system. This ratio ensures that the first aspherical mirror 30 provides the primary focal length of the system. When this ratio is greater than the upper limit of expression (3), the first aspherical mirror 30 fails to provide the primary focal length of the system. When this ratio is less than the lower limit of expression (3), the focal length of the first aspherical mirror 30 is too large, resulting in an excessively large thickness, which affects the size of the optical system.

[0080] Alternatively, the optical system according to each embodiment may satisfy the following conditional expression (4-1):

[0081]

[0082] Among them, f m1 is the focal length of the first superlens 10.

[0083] Conditional expression (4-1) relates to the ratio of the focal length of the first metalens 10 to the effective focal length of the optical system. This ratio ensures phase aberration compensation across the entire field of view and spherical aberration correction at the edges of the field of view. When this ratio is greater than the upper limit of expression (4-1), the focal length of the first metalens 10 in the optical system is too low, resulting in poor light beam adjustment capabilities and an inability to achieve complete light alignment within the system length. When this ratio is less than the lower limit of expression (4-1), the focal length of the first metalens 10 is too high, resulting in excessive dispersion in the optical system.

[0084] Alternatively, the optical system according to each embodiment may satisfy the following conditional expression (4-2):

[0085]

[0086] Among them, f m2 is the focal length of the second super lens 20.

[0087] Conditional expression (4-2) relates to the ratio of the focal length of the second metalens 20 to the effective focal length of the optical system. This ratio ensures phase aberration compensation across the entire field of view and spherical aberration correction at the edges of the field of view. When this ratio is greater than the upper limit of expression (4-2), the focal length of the second metalens 20 in the optical system is too low, resulting in poor light beam adjustment capabilities and an inability to achieve complete light alignment within the system length. When this ratio is less than the lower limit of expression (4-2), the focal length of the second metalens 20 is too high, resulting in excessive dispersion in the optical system.

[0088] Alternatively, the optical system according to each embodiment may satisfy the following conditional expression (5) and conditional expression (6):

[0089] 1.20mm≤max(d a1 ,d a2 )≤1.42mm (5);

[0090] min(d a1 ,d a2 )<1mm (6);

[0091] where d a1 is the thickness of the first aspherical mirror 30, d a2 is the thickness of the second aspherical mirror 40.

[0092] Conditional expressions (5) and (6) involve the thickness of the first aspheric mirror 30 and the second aspheric mirror 40. When the larger thickness of the two satisfies expression (5), the smaller thickness of the two satisfies expression (6) at the same time. Since the metalens has a relatively obvious negative dispersion for imaging of a wide spectrum light source, when the optical system uses two metalens, the thickness of the aspheric lens needs to bring sufficient positive dispersion to compensate or pre-compensate for it. When the thickness is less than the lower limit in expression (5), the optical system will produce excessive dispersion; when the thickness is greater than the upper limit in expressions (5) and (6), the overall thickness of the optical system will lose its constraint, affecting the size of the optical system.

[0093] Alternatively, the optical system according to each embodiment may satisfy the following conditional expression (7):

[0094] max(n m1 ,n m2 )<1.5≤min(n a1 ,n a2 ) (7);

[0095] where n m1 is the refractive index of the first superlens 10, n m2 is the refractive index of the second superlens 20, n a1 is the refractive index of the first aspherical mirror 30, n a2 is the refractive index of the second aspherical mirror 40.

[0096] Conditional expression (7) involves the refractive indices of the first metalens 10, the second metalens 20, the first aspheric mirror 30, and the second aspheric mirror 40. In the left-hand side of expression (7), the refractive indices of the first metalens 10 and the second metalens 20 are less than the upper limit of the left-hand side, which can reduce the deviation of light when it is obliquely incident, thereby reducing the influence of the metalens' base material on the light. In the right-hand side of expression (7), the refractive indices of the first aspheric mirror 30 and the second aspheric mirror 40 are greater than the lower limit of the right-hand side, which increases the aspheric mirror's ability to control light while reducing the lens thickness and the volume of the optical system.

[0097] In the embodiment of the present application and various optional embodiments, the surface phase distribution of the first superlens 10 and the second superlens 20 may satisfy the following expression:

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] Where r is the distance from the center of the superlens to the center of any nanostructure; λ is the operating wavelength, is any phase related to the working wavelength, x, y are the mirror coordinates of the metalens, f m is the focal length of the metalens. The phase of the metalens can be expressed by a high-order polynomial, wherein the high-order polynomial includes an even-order polynomial and an odd-order polynomial. In the embodiment of the present application, compared with formulas (8), (9), (10), (14) and (15), formulas (11), (12) and (13) can not only optimize the phase that satisfies the even-order polynomial, but also optimize the phase that satisfies the odd-order polynomial without destroying the rotational symmetry of the metalens phase, thereby significantly improving the optimization freedom of the metalens. It should be noted that in formulas (8), (9), (10), (14) and (15), a1 is less than zero; while in formulas (11), (12) and (13), a2 is less than zero.

[0107] In the embodiment of the present application and various optional embodiments, the surface shapes of the first aspheric mirror 30 and the second aspheric mirror 40 may be even aspheric surfaces, satisfying the following expression:

[0108]

[0109] Wherein, z is the surface vector parallel to the z-axis of the aspheric lens, c is the center point curvature (1 / R), k is the quadratic surface constant, and A to J correspond to high-order coefficients respectively.

[0110] According to an embodiment of the present application, the optical system further includes a filter 50. The filter 50 can be used to protect the sensor from being burned, or to improve the night vision performance of the optical system.

[0111] The present application will be exemplarily described below with reference to Examples 1 to 7.

[0112] Example 1

[0113] Example 1 provides an optical system, see Figure 1 The lens sequence is: first super lens 10, first aspheric mirror 30, second super lens 20, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 1, 2 and 3 respectively:

[0114] Table 1

[0115] parameter data System volume (TTL) 4.85mm Field of view (2ω) 70° F-number 2.75 Effective focal length 3.12mm Working band Visible light (400nm-700nm)

[0116] Table 2

[0117] Surface serial number Surface type Radius (mm) Thickness (mm) Material 1 aperture unlimited 0.00 - 2 spherical surface unlimited 0.32 1.46，67.8 3 metasurfaces unlimited 0.14 - 4 even aspherical surface -23.76 1.26 1.57，71.3 5 even aspherical surface -1.61 1.05 - 6 spherical surface unlimited 0.32 1.46，67.8 7 metasurfaces unlimited 0.73 - 8 even aspherical surface 3.05 0.37 1.67，47.2 9 even aspherical surface 1.38 0.25 - 10 spherical surface unlimited 0.20 1.52，64.2 11 spherical surface unlimited 0.30 - 12 Image plane unlimited - -

[0118] Table 3

[0119] Surface serial number 4 5 8 9 K 99.8053501 0.632560654 -60.5416517 -2.48204364 A -0.1010627 0.036575768 -0.10029052 -0.19037914 B 0.552229745 -0.20729684 -0.11126149 0.076955805 C -4.02279052 0.572766201 -0.0157591 -0.01399439 D 13.90675135 -0.8837397 0.206651879 -8.133E-004 E -28.9927632 0.756896632 -0.21012033 3.8306E-004 F 33.75330748 -0.33691325 0.087999406 3.2254E-005 G -18.5293383 0.059444486 -0.01407678 -1.130E-005

[0120] The performance output of Example 1 is as follows Figure 2-4 As shown. Figure 2 As shown in FIG. 1 , the MTF of the optical system in Example 1 is close to the diffraction limit in the full field of view, and the curve is gentle, which means it has excellent resolution. Figure 3 As shown in the left figure, the field curvature of the optical system is less than 0.1mm, which means it has excellent field curvature control capability. Figure 3 As shown in the right figure, the distortion of the optical system is less than 5%, which means it has excellent distortion control capability. Figure 4 As shown, the longitudinal aberration of the optical system is less than 0.07 mm, which means it has excellent chromatic aberration correction capability.

[0121] Example 2

[0122] Example 2 provides an optical system, see Figure 5 The lens sequence is: first super lens 10, first aspheric mirror 30, second super lens 20, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 4, 5 and 6 respectively:

[0123] Table 4

[0124] parameter data System volume (TTL) 4.92mm Field of view (2ω) 70° F-number 2.79 Effective focal length 3.17mm Working band Visible light (400nm-700nm)

[0125] Table 5

[0126] Surface serial number Surface type Radius (mm) Thickness (mm) Material 1 aperture unlimited 0.00 - 2 spherical surface unlimited 0.32 1.46，67.8 3 metasurfaces unlimited 0.15 - 4 even aspherical surface -79.28 1.20 1.57，71.3 5 even aspherical surface -1.70 0.93 - 6 spherical surface unlimited 0.32 1.46，67.8 7 metasurfaces unlimited 0.71 - 8 even aspherical surface 2.25 0.36 1.67，47.2 9 even aspherical surface 1.25 0.22 - 10 spherical surface unlimited 0.50 1.52，64.2 11 spherical surface unlimited 0.30 - 12 Image plane unlimited - -

[0127] Table 6

[0128]

[0129]

[0130] The performance output of Example 2 is as follows Figure 6-8 As shown. Figure 6 As shown in FIG. 2 , the MTF of the optical system in Example 2 is close to the diffraction limit in the full field of view, and the curve is gentle, which means it has excellent resolution. Figure 7 As shown in the left figure, the field curvature of the optical system is less than 0.1mm, which means it has excellent field curvature control capability. Figure 7As shown in the right figure, the distortion of the optical system is less than 5%, which means it has excellent distortion control capability. Figure 8 As shown, the longitudinal aberration of the optical system is less than or equal to 0.07 mm, which means it has excellent chromatic aberration correction capability.

[0131] Example 3

[0132] Example 3 provides an optical system, see Figure 9 The lens sequence is: first aspheric mirror 30, first super lens 10, second super lens 20, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 7, 8 and 9 respectively:

[0133] Table 7

[0134] parameter data System volume (TTL) 4.81mm Field of view (2ω) 70° F-number 2.86 Effective focal length 3.31mm Working band Visible light (400nm-700nm)

[0135] Table 8

[0136] Surface serial number Surface type Radius (mm) Thickness (mm) Material 1 aperture unlimited 0.24 - 2 even aspherical surface 4.94 0.73 1.74，50.8 3 even aspherical surface -4.78 0.30 - 4 metasurfaces unlimited 0.32 1.46，67.8 5 spherical surface unlimited 0.30 - 6 spherical surface unlimited 0.32 1.46，67.8 7 metasurfaces unlimited 0.47 - 8 even aspherical surface 5.84 1.42 1.85，23.8 9 even aspherical surface 2.41 0.31 - 10 spherical surface unlimited 0.20 1.52，64.2 11 spherical surface unlimited 0.20 - 12 Image plane unlimited - -

[0137] Table 9

[0138]

[0139]

[0140] The performance output of Example 3 is as follows Figure 10-12 As shown. Figure 10 As shown in FIG. 3 , the MTF of the optical system in Example 3 is close to the diffraction limit in the whole field of view, and the curve is gentle, which shows excellent resolution. Figure 11 As shown in the left figure, the field curvature of the optical system is less than 0.35mm, which means it has excellent field curvature control capability. Figure 11 As shown in the right figure, the distortion of the optical system is less than 5%, which means it has excellent distortion control capability. Figure 12 As shown, the longitudinal aberration of the optical system is less than 0.025 mm, which means it has excellent chromatic aberration correction capability.

[0141] Example 4

[0142] Example 4 provides an optical system, see Figure 13 The lens sequence is: first super lens 10, second super lens 20, first aspheric mirror 30, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 10, 11 and 12 respectively:

[0143] Table 10

[0144] parameter data System volume (TTL) 4.85mm Field of view (2ω) 70° F-number 2.76 Effective focal length 3.23mm Working band Visible light (400nm-700nm)

[0145] Table 11

[0146]

[0147]

[0148] Table 12

[0149] Surface serial number 4 5 8 9 K -1.71232301 -0.36466912 -81.639367 -4.07719066 A 0.019832053 0.011476934 -0.2866947 -0.12230672 B -3.918E-004 -1.276E-003 0.032505861 0.039754846 C -2.393E-003 1.6278E-003 -4.993E-003 -4.452E-003 D -9.928E-004 -2.258E-005 5.8582E-003 -9.182E-004 E 2.1308E-004 -5.745E-004 -8.099E-004 8.9870E-005 F 2.9170E-004 -2.494E-004 -2.916E-003 4.1116E-005 G -2.254E-004 6.485E-005 -5.039E-004 -6.137E-006

[0150] The performance output of Example 4 is as follows Figure 14-16 As shown. Figure 14 As shown in FIG. 4 , the MTF of the optical system in Example 4 is close to the diffraction limit in the full field of view, and the curve is gentle, which shows excellent resolution. Figure 15 As shown in the left figure, the field curvature of the optical system is less than 0.05mm, which means it has excellent field curvature control capability. Figure 15 As shown in the right figure, the distortion of the optical system is less than 3%, which means it has excellent distortion control capability. Figure 16 As shown, the longitudinal aberration of the optical system is less than 0.03 mm, which means it has excellent chromatic aberration correction capability.

[0151] Example 5

[0152] Example 5 provides an optical system, see Figure 17 The lens sequence is: first super lens 10, second super lens 20, first aspheric mirror 30, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 13, 14 and 15 respectively:

[0153] Table 13

[0154] parameter data System volume (TTL) 4.81mm Field of view (2ω) 70° F-number 2.73 Effective focal length 3.19mm Working band Visible light (400nm-700nm)

[0155] Table 14

[0156] Surface serial number Surface type Radius (mm) Thickness (mm) Material 1 aperture unlimited 0.00 - 2 spherical surface unlimited 0.32 1.46，67.8 3 metasurfaces unlimited 0.29 - 4 metasurfaces unlimited 0.32 1.46，67.8 5 spherical surface unlimited 0.01 - 6 even aspherical surface 3.07 1.38 1.50，70.4 7 even aspherical surface -2.06 1.36 - 8 even aspherical surface 8.19 0.33 1.54，70.1 9 even aspherical surface 1.38 0.30 - 10 spherical surface unlimited 0.30 1.52，64.2 11 spherical surface unlimited 0.20 - 12 Image plane unlimited - -

[0157] Table 15

[0158] Surface serial number 6 7 8 9 K -1.73249486 -0.32092279 -100.000011 -4.05490021 A 0.019774477 0.010211816 -0.29797459 -0.12642595 B -3.239E-004 -1.261E-003 0.031165707 0.040435426 C -2.432E-003 1.6795E-003 -4.555E-003 -4.407E-003 D -9.488E-004 -4.238E-006 6.2847E-003 -9.618E-004 E 3.2927E-004 -5.541E-004 -7.474E-004 7.2614E-005 F 3.7526E-004 -2.231E-004 -2.979E-003 3.9038E-005 G -2.104E-004 9.039E-005 -5.522E-004 -4.863E-006

[0159] The performance output of Example 5 is as follows Figure 18-20 As shown. Figure 18 As shown in FIG. 5 , the MTF of the optical system in Example 5 is close to the diffraction limit in the whole field of view, and the curve is gentle, which shows excellent resolution. Figure 19 As shown in the left figure, the field curvature of the optical system is less than 0.05mm, which means it has excellent field curvature control capability. Figure 19 As shown in the right figure, the distortion of the optical system is less than 4%, which means it has excellent distortion control capability. Figure 20As shown, the longitudinal aberration of the optical system is less than 0.03 mm, which means it has excellent chromatic aberration correction capability.

[0160] Example 6

[0161] Example 6 provides an optical system, see Figure 21 The lens sequence is: first super lens 10, second super lens 20, first aspheric mirror 30, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 16, 17 and 18 respectively:

[0162] Table 16

[0163] parameter data System volume (TTL) 4.98mm Field of view (2ω) 70° F-number 2.86 Effective focal length 3.35mm Working band Visible light (400nm-700nm)

[0164] Table 17

[0165] Surface serial number Surface type Radius (mm) Thickness (mm) Material 1 aperture unlimited 0.13 - 2 even aspherical surface 113.57 0.95 1.74，50.8 3 even aspherical surface -2.60 0.11 - 4 metasurfaces unlimited 0.32 1.46，67.8 5 spherical surface unlimited 0.19 - 6 spherical surface unlimited 0.32 1.46，67.8 7 metasurfaces unlimited 1.05 - 8 even aspherical surface 5.52 1.21 1.85，23.8 9 even aspherical surface 2.03 0.29 - 10 spherical surface unlimited 0.20 1.52，64.2 11 spherical surface unlimited 0.20 - 12 Image plane unlimited - -

[0166] Table 18

[0167]

[0168]

[0169] The performance output of Example 6 is as follows Figure 22-24 As shown. Figure 22 As shown in FIG. 6 , the MTF of the optical system in Example 6 is close to the diffraction limit in the whole field of view, and the curve is gentle, which shows excellent resolution. Figure 23 As shown in the left figure, the field curvature of the optical system is less than 0.04mm, which means it has excellent field curvature control capability. Figure 23 As shown in the right figure, the distortion of the optical system is less than 3%, which means it has excellent distortion control capability. Figure 24 As shown, the longitudinal aberration of the optical system is less than 0.025 mm, which means it has excellent chromatic aberration correction capability.

[0170] Example 7

[0171] Example 7 provides an optical system, see Figure 25 The lens sequence is: first super lens 10, first aspheric mirror 30, second super lens 20, second aspheric mirror 40. Its system parameters, surface parameters and aspheric coefficients are shown in Tables 19, 20 and 21 respectively:

[0172] Table 19

[0173] parameter data System volume (TTL) 5.12mm Field of view (2ω) 70° F-number 2.90 Effective focal length 3.28mm Working band Visible light (400nm-700nm)

[0174] Table 20

[0175]

[0176]

[0177] Table 21

[0178] Surface serial number 2 3 8 9 K -100 0.848256381 -11.5478536 -1.07288295 A -0.09678111 0.030849017 -0.07795827 -0.33455296 B 0.470265373 -0.18951482 -0.15527714 0.123430793 C -3.57081626 0.540793088 -0.01557419 -0.01901011 D 13.41871674 -0.85694116 0.228003158 -2.199E-003 E -30.216665 0.757571308 -0.21068168 6.7325E-004 F 36.94498227 -0.35064457 0.079209962 5.9876E-005 G -19.8618737 0.065659788 -0.01136673 -1.801E-005

[0179] The performance output of Example 7 is as follows Figures 26-28 As shown. Figure 26 As shown in FIG. 1 , the MTF of the optical system in Example 1 is close to the diffraction limit in the full field of view, and the curve is gentle, which means it has excellent resolution. Figure 27 As shown in the left figure, the field curvature of the optical system is less than 0.08mm, which means it has excellent field curvature control capability. Figure 27 As shown in the right figure, the distortion of the optical system is less than 5%, which means it has excellent distortion control capability. Figure 28 As shown, the longitudinal aberration of the optical system is less than 0.06 mm, which means it has excellent chromatic aberration correction capability.

[0180] Table 22 summarizes all parameters and conditional expressions in the above Examples 1-7.

[0181] Table 22

[0182]

[0183]

[0184] In the above-described embodiments and preferred embodiments, the optical system provided by this application achieves the following performance outputs: TTL < 5mm; MTF of approximately 0.2 at a cutoff frequency of 300 lp / mm with a maximum field of view; system field curvature less than 0.3mm, distortion less than 5%; and axial aberration less than 0.1mm. Conventional technology, however, requires at least seven aspheric lenses to achieve these imaging standards. This increases the cost of the optical system and also reduces the yield rate of the optical system due to the difficulty in processing and aligning aspheric lenses.

[0185] In the above embodiments and preferred embodiments, on the one hand, a super lens is used to provide a compensating phase to eliminate residual aberration and spherical aberration of the edge field of view, thereby reducing the system volume and manufacturing cost; on the other hand, achromatization is performed by combining different materials, negative dispersion of the super lens and positive dispersion of the traditional lens, and a four-piece lens group is used to achieve good imaging effects.

[0186] According to another aspect of the present application, the optical system is combined with an image sensing device and applied to image pickup devices such as cameras, video cameras, mobile phones, and telescopes, thereby obtaining an image pickup device with both a small size and excellent optical performance.

[0187] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solution that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An optical system, characterized in that: The optical system comprises an aperture, a first super lens (10), a second super lens (20), a first aspheric mirror (30), and a second aspheric mirror (40); Along the incident light path, the aperture is located on the first surface of the optical system; the second aspheric mirror is the last lens in the optical system; the first super lens (10) is arranged at any position between the aperture and the second super lens (20), and the first aspheric mirror (30) is arranged at any position between the aperture and the second aspheric mirror (40); Furthermore, the optical system satisfies at least the following conditional expressions: ； ； ； ； ； in, is the effective focal length of the optical system, is the focal length of the first aspheric mirror (30), is the focal length of the second aspherical mirror (40), is the focal length of the first superlens (10), is the focal length of the second super lens (20).

2. The optical system according to claim 1, wherein: The optical system also satisfies the following conditional expression: ； ； in, is the thickness of the first aspheric mirror (30), is the thickness of the second aspherical mirror (40).

3. The optical system according to claim 1, wherein: The optical system also satisfies the following conditional expression: ； in, is the refractive index of the first superlens (10), is the refractive index of the second superlens (20), is the refractive index of the first aspheric mirror (30), is the refractive index of the second aspherical mirror (40).

4. The optical system according to claim 1, wherein: The first aspheric mirror (30) and the second aspheric mirror (40) have even-order aspheric surfaces.

5. The optical system according to claim 1, wherein: The object side surface of the first aspheric mirror (30) is concave, and The image side surface of the first aspherical mirror (30) is convex.

6. The optical system according to claim 1, wherein: The object side surface of the second aspherical mirror (40) is concave, and The image side surface of the second aspherical mirror (40) is concave.

7. The optical system according to any one of claims 1 to 6, characterized in that: Along the incident light path, the optical system sequentially comprises an aperture, a first super lens (10), a first aspheric mirror (30), a second super lens (20), and a second aspheric mirror (40).

8. The optical system according to any one of claims 1 to 6, characterized in that: Along the incident light path, the optical system sequentially comprises an aperture, a first super lens (10), a second super lens (20), a first aspheric mirror (30), and a second aspheric mirror (40).

9. The optical system according to any one of claims 1 to 6, characterized in that: Along the incident light path, the optical system sequentially comprises an aperture, a first aspheric mirror (30), a first super lens (10), a second super lens (20), and a second aspheric mirror (40).

10. An image pickup device, characterized in that: The image pickup device comprises the optical system according to any one of claims 1 to 9 and an image sensing device; The image sensing device is configured to receive the image generated by the optical system.

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