Imaging optical system, imaging apparatus, and electronic apparatus

Abstract

The present invention discloses an imaging optical system, an imaging device, and an electronic device that can reduce the total optical length of a lens while maintaining high resolution. The imaging optical system includes at least one meta-lens (104) having a nanostructure and three or more lenses not having the nanostructure. The imaging optical system includes at least one meta-lens having a nanostructure and at least one lens not having the nanostructure, wherein the imaging optical system satisfies 0.5 < TTL / f < 10, and the wavelength of incident light satisfies the following condition: 300 nm < wavelength < 700 nm.

Description

Technical Field

[0001] This invention relates to imaging optical systems, imaging devices, and electronic devices for mobile terminals such as mobile phones or smartphones, as well as personal digital assistants (PDAs). In particular, it relates to imaging optical systems, imaging devices, and electronic devices that use imaging elements such as relatively small and thin charge-coupled device (CCD) sensors or complementary metal-oxide-semiconductor (CMOS) sensors. Background Technology

[0002] In recent years, the size and thickness of electronic devices such as mobile phones, smartphones, and PDAs have shrunk. As a result, there is a strong need to shorten the total track length (TTL) of the lenses in imaging optical systems mounted on electronic devices.

[0003] For smaller electronic devices, a large F-number is needed to expand the focusing range. However, as the F-number increases, the amount of light passing through the aperture decreases. On the other hand, due to the recent increase in the number of lenses to accommodate high zoom capabilities, the light loss through many lenses also increases. Therefore, when the F-number increases further, the amount of light passing through the aperture decreases even more, resulting in a deterioration in image quality.

[0004] Metasurfaces have been developed as a leading platform for achieving better image quality when developing miniaturized optical components. For example, metasurfaces can function as phase shifters with subwavelength spacing, exhibiting excellent control over optical properties. However, specific research on the practical applications of metasurfaces is currently lacking. Summary of the Invention

[0005] The present invention aims to provide an imaging optical system, imaging device, and electronic device that can reduce the overall optical length of the lens while maintaining image quality.

[0006] According to a first aspect, an imaging optical system is provided, comprising a plurality of optical elements, wherein the plurality of optical elements includes:

[0007] At least one superlens having a nanostructure formed on at least one side;

[0008] Three or more lenses, without the aforementioned nanostructure.

[0009] According to this approach, a superlens with a nanostructure is inserted into three or more lenses without a nanostructure. Therefore, by generating chromatic aberration in opposite directions through the superlens, chromatic aberration caused by shortening the overall length of the optical system can be eliminated in visible light. Since chromatic aberration can be corrected, high optical performance can be ensured while reducing the overall length.

[0010] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0011] 0.5 <TTL / f<10.0,

[0012] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the wavelength satisfies the following condition:

[0013] 300nm < wavelength < 700nm.

[0014] According to this implementation method, by setting the range of the above conditions, better optical performance can be ensured while shortening the total length.

[0015] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0016] 0.6 <TTL / f<5.0。

[0017] According to this implementation method, by setting the range of the above conditions, better optical performance can be ensured while shortening the total length.

[0018] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0019] 0.6 <TTL / f<2.0。

[0020] According to this implementation method, by setting the range of the above conditions, better optical performance can be ensured while shortening the total length.

[0021] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0022] 0.01 < |fconv / fmeta| < 0.50

[0023] Where fconv is the focal length of the optical system from the optical element on the image side (not the superlens closest to the object side) to the optical element closest to the image.

[0024] fmeta is the focal length of the superlens that most closely approximates the object.

[0025] Wherein, the focal length is –0.5 / C1.

[0026] Where C1 is the quadratic coefficient of the phase function of the superlens, and the wavelength satisfies the following condition:

[0027] 300nm < wavelength < 700nm.

[0028] The above condition is an expression relating the focal length of the superlens to the focal length of the optical system arranged on the image side of the superlens. According to this implementation, high optical performance can be ensured by satisfying this condition.

[0029] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0030] 0.01 < |fconv / fmeta| < 0.20.

[0031] According to this implementation method, by setting the range of the above conditions, better optical performance can be ensured while shortening the total length.

[0032] In one possible implementation of the first aspect, the superlens is positioned near the aperture stop of the imaging optical system, and the wavelength satisfies the following condition:

[0033] 300nm < wavelength < 700nm.

[0034] According to this implementation, by placing the superlens in the portion of the light spectrum near the aperture stop where the light is at a high altitude, axial chromatic aberration can be appropriately corrected. Furthermore, high optical performance can be ensured.

[0035] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0036] 0.4 < |TTLconv / fconv| < 2.0

[0037] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0038] fconv is the focal length of the optical system from the optical element on the image side (not the superlens closest to the object side) to the optical element closest to the image, and the wavelength satisfies the following condition:

[0039] 300nm < wavelength < 700nm.

[0040] The above condition refers to the ratio of the focal length of the optical system arranged on the image side of the superlens to the distance between the optical systems arranged on the image side of the superlens. According to this implementation, the total length of the optical system arranged on the image side of the superlens can be shortened. Therefore, the length of the entire optical system can be reduced.

[0041] Regarding one possible implementation of the first aspect, the superlens satisfies the following condition:

[0042] 1.5 <ndmeta<5.0,

[0043] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0044] The aforementioned condition refers to the refractive index of the structure formed on the superlens for the d-line. According to this implementation method, by satisfying this condition, superlenses can be manufactured more easily. Furthermore, large-scale production can be ensured. Additionally, since the height of the nanostructure can be reduced, the overall length can be shortened.

[0045] Regarding one possible implementation of the first aspect, the superlens satisfies the following condition:

[0046] 1.8 <ndmeta<3.8,

[0047] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0048] According to this implementation method, by satisfying this condition, it is easier to manufacture superlenses.

[0049] Regarding one possible implementation of the first aspect, the nanostructure is composed of nanopillars, which satisfy the following condition:

[0050] 2.0 <h / t<25.0,

[0051] Where h is the height of the nanopillar.

[0052] t is the diameter of the nanopillar, and the wavelength satisfies the following condition:

[0053] 300nm < wavelength < 700nm.

[0054] The above conditions are conditional expressions concerning the nanopillar structures constituting the superlens. According to this implementation, nanopillars can be easily fabricated by satisfying these conditional expressions. Furthermore, large-scale production can be ensured. Moreover, since the height of the nanostructure can be reduced, the overall length can be shortened.

[0055] According to a second aspect, an imaging optical system comprising a plurality of optical elements is provided, wherein the plurality of optical elements includes:

[0056] At least one superlens having a nanostructure formed on at least one side;

[0057] At least one lens does not have the aforementioned nanostructure.

[0058] The imaging optical system satisfies the following conditions:

[0059] 0.5 <TTL / f<10,

[0060] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

[0061] The wavelength of the incident light satisfies the following condition:

[0062] 300nm < wavelength < 700nm.

[0063] Based on this approach, a superlens with a nanostructure is inserted into a conventional optical system. Therefore, by generating chromatic aberration in the opposite direction using the superlens, chromatic aberration caused by shortening the overall length of the optical system can be eliminated in visible light. Since chromatic aberration can be corrected, high optical performance can be ensured while reducing the overall length.

[0064] Regarding one possible implementation of the second aspect, the imaging optical system also satisfies the following condition:

[0065] 0.6 <TTL / f<5.0,

[0066] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

[0067] Regarding one possible implementation of the second aspect, the imaging optical system also satisfies the following condition:

[0068] 0.6 <TTL / f<2.0。

[0069] Regarding one possible implementation of the second aspect, the imaging optical system also satisfies the following condition:

[0070] 0.01 < |fconv / fmeta| < 0.50

[0071] Where fconv is the focal length of the optical system from the optical element on the image side (not the superlens closest to the object side) to the optical element closest to the image.

[0072] fmeta is the focal length of the superlens that most closely approximates the object.

[0073] Wherein, the focal length is –0.5 / C1.

[0074] Where C1 is the quadratic coefficient of the phase function of the superlens.

[0075] Regarding one possible implementation of the second aspect, the imaging optical system also satisfies the following condition:

[0076] 0.01 < |fconv / fmeta| < 0.20.

[0077] In one possible implementation of the second aspect, the superlens is arranged near the aperture of the imaging optical system.

[0078] Regarding one possible implementation of the second aspect, the imaging optical system also satisfies the following condition:

[0079] 0.4 < |TTLconv / fconv| < 2.0

[0080] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0081] Wherein, fconv is the focal length of the optical system from the optical element on the image side, rather than the superlens closest to the object side, to the optical element closest to the image.

[0082] Regarding one possible implementation of the second aspect, the superlens satisfies the following condition:

[0083] 1.5 <ndmeta<5.0,

[0084] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0085] Regarding one possible implementation of the second aspect, the superlens satisfies the following condition:

[0086] 1.8 <ndmeta<3.8,

[0087] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0088] Regarding one possible implementation of the second aspect, the nanostructure is composed of nanopillars, which satisfy the following condition:

[0089] 2.0 <h / t<25.0,

[0090] Where h is the height of the nanopillar.

[0091] t is the diameter of the nanopillar.

[0092] According to a third aspect, an imaging optical system for light with wavelengths satisfying the following conditions is provided:

[0093] 300nm < wavelength < 700nm

[0094] The imaging optical system includes at least one optical element, wherein the at least one optical element includes:

[0095] At least one superlens has a nanostructure formed on at least one side.

[0096] According to this aspect, the imaging optical system includes at least one superlens having a nanostructure formed on at least one side. Therefore, by generating chromatic aberration in the opposite direction using the superlens, chromatic aberration generated by shortening the overall length of the optical system portion can be eliminated in visible light. Since chromatic aberration can be corrected, high optical performance and a reduced overall length can be ensured.

[0097] In one possible implementation of the third aspect, the imaging optical system includes four or more superlenses, each having a nanostructure formed on at least one side.

[0098] Regarding one possible implementation of the third aspect, the imaging optical system also satisfies the following condition:

[0099] 0.6 <TTL / f<5.0,

[0100] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

[0101] Regarding one possible implementation of the third aspect, the imaging optical system also satisfies the following condition:

[0102] 0.6 <TTL / f<2.0。

[0103] Regarding one possible implementation of the third aspect, the superlens satisfies the following

[0104] condition:

[0105] 1.5 <ndmeta<5.0,

[0106] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0107] Regarding one possible implementation of the third aspect, the superlens satisfies the following condition:

[0108] 1.8 <ndmeta<3.8,

[0109] Among them, ndmeta is the refractive index of the nanostructure for the d line.

[0110] Regarding a possible implementation of the third aspect, the nanostructure consists of nanocolumns, and the nanocolumns satisfy the following conditions:

[0111] 2.0 < h / t < 25.0,

[0112] where h is the height of the nanocolumn,

[0113] and t is the diameter of the nanocolumn.

[0114] Regarding a possible implementation of the first aspect, the imaging optical system satisfies the following conditions:

[0115] 1.0 < TTL / f < 15.0,

[0116] 0.6 < F - number < 1.6,

[0117] where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the F - number is the F - number of the imaging optical system.

[0118] The wavelength of the incident light satisfies the following conditions:

[0119] 700nm < wavelength < 1700nm.

[0120] Regarding a possible implementation of the first aspect, the imaging optical system satisfies the following conditions:

[0121] 1.5 < TTL / f < 7.0,

[0122] 0.8 < F - number < 1.4.

[0123] Regarding a possible implementation of the first aspect, the imaging optical system satisfies the following conditions:

[0124] 2.0 < TTL / f < 4.0,

[0125] 0.9 ≤ F - number < 1.2.

[0126] Regarding a possible implementation of the first aspect, the imaging optical system further satisfies the following conditions:

[0127] 0.01 < |fconv / fmeta| < 0.50,

[0128] where fconv is the focal length of the optical system from the superlens on the image side rather than the closest to the object side to the optical element closest to the image.

[0129] fmeta is the focal length of the superlens that most closely approximates the object.

[0130] Wherein, the focal length is –0.5 / C1.

[0131] Where C1 is the quadratic coefficient of the phase function of the superlens, and the wavelength satisfies the following condition:

[0132] 700nm < wavelength < 1700nm.

[0133] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0134] 0.01 < |fconv / fmeta| < 0.35.

[0135] In one possible implementation of the first aspect, the superlens is positioned near the aperture stop of the imaging optical system, and the wavelength satisfies the following condition:

[0136] 700nm < wavelength < 1700nm.

[0137] Regarding one possible implementation of the first aspect, the imaging optical system also satisfies the following conditions:

[0138] 0.4 < |TTLconv / fconv| < 2.5

[0139] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0140] fconv is the focal length of an optical system from the image-side optical element (not the superlens closest to the object side) to the optical element closest to the image.

[0141] The wavelength satisfies the following condition:

[0142] 700nm < wavelength < 1700nm.

[0143] Regarding one possible implementation of the first aspect, the superlens satisfies the following condition:

[0144] 1.5 <ndmeta<5.0,

[0145] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0146] Regarding one possible implementation of the first aspect, the superlens satisfies the following condition:

[0147] 1.8 <ndmeta<3.8。

[0148] In a possible implementation of the first aspect, the nanostructure is composed of nanocolumns, and the nanocolumns satisfy the following conditions:

[0149] 1.0 < h / t < 25.0,

[0150] where h is the height of the nanocolumn,

[0151] and t is the diameter of the nanocolumn.

[0152] According to the fourth aspect, an imaging optical system including a plurality of optical elements is provided, wherein the plurality of optical elements include:

[0153] at least one metalens having a nanostructure formed on at least one side;

[0154] at least one lens not having the nanostructure,

[0155] wherein the metalens satisfies the following conditions:

[0156] 1.0 < TTL / f < 15.0,

[0157] 0.6 < F-number < 1.6,

[0158] where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, the F-number is the F-number of the imaging optical system, and the wavelength satisfies the following conditions:

[0159] 700 nm < wavelength < 1700 nm.

[0160] According to this aspect, the metalens with the nanostructure is inserted into a conventional optical system. Therefore, by generating chromatic aberration of the metalens in the opposite direction, the chromatic aberration generated by shortening the total length of a part of the optical system can be eliminated in the NIR. Since chromatic aberration can be corrected, high optical performance can be ensured and the total length can be shortened.

[0161] In a possible implementation of the fourth aspect, the imaging optical system satisfies the following conditions:

[0162] 1.5 < TTL / f < 7.0,

[0163] 0.8 < F-number < 1.4.

[0164] In a possible implementation of the fourth aspect, the imaging optical system satisfies the following conditions:

[0165] 2.0 < TTL / f < 4.0,

[0166] 0.9 ≤ F-number < 1.2.

[0167] Regarding one possible implementation of the fourth aspect, the imaging optical system also satisfies the following condition:

[0168] 0.01 < |fconv / fmeta| < 0.50

[0169] Where fconv is the focal length of the optical system from the optical element on the image side (not the superlens closest to the object side) to the optical element closest to the image.

[0170] fmeta is the focal length of the superlens that most closely approximates the object.

[0171] Wherein, the focal length is –0.5 / C1.

[0172] Where C1 is the quadratic coefficient of the phase function of the superlens.

[0173] Regarding one possible implementation of the fourth aspect, the imaging optical system also satisfies the following condition:

[0174] 0.01 < |fconv / fmeta| < 0.35.

[0175] In one possible implementation of the fourth aspect, the superlens is arranged near the aperture of the imaging optics system.

[0176] Regarding one possible implementation of the fourth aspect, the imaging optical system also satisfies the following condition:

[0177] 0.4 < |TTLconv / fmeta| < 2.5,

[0178] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0179] fconv is the focal length of the optical system from the optical element on the image side, rather than the superlens closest to the object side, to the optical element closest to the image.

[0180] Regarding one possible implementation of the fourth aspect, the superlens satisfies the following condition:

[0181] 1.5 <ndmeta<5.0,

[0182] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0183] Regarding one possible implementation of the fourth aspect, the superlens satisfies the following condition:

[0184] 1.8 < ndmeta < 3.8.

[0185] Regarding a possible implementation of the fourth aspect, the nanostructure is composed of nanocolumns, and the nanocolumns satisfy the following conditions:

[0186] 1.0 < h / t < 25.0,

[0187] where h is the height of the nanocolumn,

[0188] and t is the diameter of the nanocolumn.

[0189] According to the fifth aspect, there is provided an imaging optical system for light whose wavelength satisfies the following conditions:

[0190] 700 nm < wavelength < 1700 nm,

[0191] The imaging optical system includes at least one optical element, and among them, the at least one optical element includes:

[0192] At least one meta-lens having nanostructures formed on at least one side.

[0193] According to this aspect, the imaging optical system includes at least one meta-lens having nanostructures formed on at least one side. Therefore, by generating chromatic aberration of the meta-lens in the opposite direction, the chromatic aberration generated by shortening the total length of a part of the optical system can be eliminated in the NIR. Since chromatic aberration can be corrected, high optical performance can be ensured and the total length can be shortened.

[0194] Regarding a possible implementation of the fifth aspect, the imaging optical system includes four or more meta-lenses, each having nanostructures formed on at least one side.

[0195] Regarding a possible implementation of the fifth aspect, the imaging optical system satisfies the following conditions:

[0196] 1.5 < TTL / f < 7.0,

[0197] 0.8 < F-number < 1.4,

[0198] where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the F-number is the F-number of the imaging optical system.

[0199] Regarding a possible implementation of the fifth aspect, the imaging optical system satisfies the following conditions:

[0200] 2.0 < TTL / f < 4.0,

[0201] 0.9≤F number<1.2.

[0202] Regarding one possible implementation of the fifth aspect, the superlens satisfies the following condition:

[0203] 1.5 <ndmeta<5.0,

[0204] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0205] Regarding one possible implementation of the fifth aspect, the superlens satisfies the following condition:

[0206] 1.8 <ndmeta<3.8。

[0207] Regarding one possible implementation of the fifth aspect, the nanostructure is composed of nanopillars, which satisfy the following condition:

[0208] 1.0 <h / t<25.0,

[0209] Where h is the height of the nanopillar.

[0210] t is the diameter of the nanopillar.

[0211] According to a sixth aspect, an imaging device is provided, the imaging device comprising:

[0212] Optical devices, including the aforementioned imaging optical system;

[0213] An imaging sensor for generating data based on light transmitted through the optics.

[0214] According to a seventh aspect, an electronic device including an imaging apparatus is provided, the imaging apparatus comprising:

[0215] Optical devices, including the aforementioned imaging optical system;

[0216] An imaging sensor for generating data based on light transmitted through the optics. Attached Figure Description

[0217] To more clearly describe the technical solutions of the embodiments, the accompanying drawings required for the embodiments are briefly described below. Obviously, the drawings in the following description only illustrate some embodiments, and those skilled in the art can obtain other drawings from these drawings without creative effort.

[0218] Figure 1 A diagram illustrating the construction of an optical system provided in one embodiment.

[0219] Figure 2 A perspective view of a nanopillar provided for one embodiment.

[0220] Figure 3 A diagram illustrating the method of manufacturing a superlens.

[0221] Figure 4a The specification table for line e provided in Example 1.

[0222] Figure 4b The effective focal length table provided for Example 1.

[0223] Figure 4c The surface information table provided for Example 1.

[0224] Figure 4d The aspherical coefficient table provided for Example 1.

[0225] Figure 4e A diagram illustrating the construction of the imaging optical system provided in Example 1.

[0226] Figure 4f The image shows the chromatic aberration provided in Example 1.

[0227] Figure 4g The metasurface information table provided for Example 1.

[0228] Figure 4h (a) Plan view, (b) Side view and (c) Perspective view of the superlens provided for Example 1.

[0229] Figure 4i The relationship between the target phase and the distance from the center of the superlens is provided for Example 1.

[0230] Figure 4j A graph showing the relationship between the radius of the upper surface provided in Example 1 and the phase in a nanopillar.

[0231] Figure 4k The results of the simulation of the phase of light transmitted through the nanopillar provided in Example 1.

[0232] Figure 4l The results of the simulation of light transmission through the nanopillars provided in Example 1.

[0233] Figure 4m This is the result of the simulation provided in Example 1 showing the relationship between the distance from the center of the nanopillar and the radius of the nanopillar.

[0234] Figure 4n The results of the simulation of the phase of light transmitted through the superlens provided in Example 1.

[0235] Figure 5a The specification table for line e provided in Example 2.

[0236] Figure 5b The effective focal length table provided for Example 2.

[0237] Figure 5c The surface information table provided for Example 2.

[0238] Figure 5d The aspherical coefficient table provided for Example 2.

[0239] Figure 5e A diagram illustrating the construction of the imaging optical system provided in Example 2.

[0240] Figure 5f The image shows the chromatic aberration provided in Example 2.

[0241] Figure 5g The metasurface information table provided for Example 2.

[0242] Figure 5h (a) Plan view, (b) Side view and (c) Perspective view of the superlens provided for Example 2.

[0243] Figure 5i Example 2 provides the relationship between the target phase and the distance from the center of the superlens.

[0244] Figure 5j A graph showing the relationship between the radius of the upper surface and the phase in a nanopillar, as provided in Example 2. Figure 5k The results of the simulation of the phase of light transmitted through the superlens provided in Example 2.

[0245] Figure 5l The results of the simulation of light transmission through the superlens provided in Example 2.

[0246] Figure 5m This is the result of the simulation provided in Example 2 regarding the relationship between the distance from the center of the superlens and the radius of the superlens.

[0247] Figure 5n The results of the simulation of the phase of light transmitted through the superlens provided in Example 2.

[0248] Figure 6a The specification table for line e provided in Example 3.

[0249] Figure 6b The effective focal length table provided for Example 3.

[0250] Figure 6c The surface information table provided for Example 3.

[0251] Figure 6d The aspherical coefficient table provided for Example 3.

[0252] Figure 6e A diagram illustrating the construction of the imaging optical system provided in Example 3.

[0253] Figure 6f The image shows the chromatic aberration provided in Example 3.

[0254] Figure 6g The metasurface information table provided for Example 3.

[0255] Figure 6h (a) Plan view, (b) Side view and (c) Perspective view of the superlens provided for Example 3.

[0256] Figure 6i Example 3 provides the relationship between the target phase and the distance from the center of the superlens.

[0257] Figure 6j A graph showing the relationship between the radius of the upper surface and the phase in a nanopillar, as provided in Example 3. Figure 6k The results of the simulation of the phase of light transmitted through the superlens provided in Example 3.

[0258] Figure 6l The results of the simulation of light transmission through the superlens provided in Example 3.

[0259] Figure 6m This is the result of the simulation provided in Example 3 regarding the relationship between the distance from the center of the superlens and the radius of the superlens.

[0260] Figure 6n The results of the simulation of the phase of light transmitted through the superlens provided in Example 3.

[0261] Figure 7a The specification table for line e provided in Example 4.

[0262] Figure 7b The effective focal length table provided for Example 4.

[0263] Figure 7c The surface information table provided for Example 4.

[0264] Figure 7d The aspherical coefficient table provided for Example 4.

[0265] Figure 7e A diagram illustrating the construction of the imaging optical system provided in Example 4.

[0266] Figure 7f The image showing the chromatic aberration provided in Example 4.

[0267] Figure 7g The metasurface information table provided for Example 4.

[0268] Figure 7h (a) Plan view, (b) Side view and (c) Perspective view of the superlens provided for Example 4.

[0269] Figure 7i Example 4 provides the relationship between the target phase and the distance from the center of the superlens.

[0270] Figure 7j A graph showing the relationship between the radius of the upper surface and the phase in a nanopillar, as provided in Example 4.

[0271] Figure 7k This is the result of the simulation provided in Example 4 regarding the relationship between the distance from the center of the superlens and the radius of the superlens.

[0272] Figure 8a The specification table for line e provided in Example 5.

[0273] Figure 8b The effective focal length table provided for Example 5.

[0274] Figure 8c The surface information table provided for Example 5.

[0275] Figure 8d A diagram illustrating the construction of the imaging optical system provided in Example 5.

[0276] Figure 8e The image shows the chromatic aberration provided in Example 5.

[0277] Figure 8f The metasurface information table provided in Example 5.

[0278] Figure 8g (a) Plan view, (b) Side view and (c) Perspective view of the superlens provided in Example 5.

[0279] Figure 8h The example 5 illustrates the relationship between the target phase of light transmitted through the first superlens and the distance from the center of the first superlens.

[0280] Figure 8i A graph showing the relationship between the radius of the upper surface and the phase in a nanopillar, as provided in Example 5.

[0281] Figure 8j The results of the simulation provided in Example 5 show the relationship between the distance from the center of the first superlens and the radius of the superlens.

[0282] Figure 8k (a) Plan view, (b) Side view and (c) Perspective view of the second superlens provided for Example 5.

[0283] Figure 8l The example 5 illustrates the relationship between the target phase of the light transmitted through the second superlens and the distance from the center of the second superlens.

[0284] Figure 8mThe results of the simulation provided in Example 5 show the relationship between the distance from the center of the second superlens and the radius of the superlens.

[0285] Figure 8n (a) Plan view, (b) Side view and (c) Perspective view of the third superlens provided in Example 5.

[0286] Figure 8o The example 5 illustrates the relationship between the target phase of the light transmitted through the third superlens and the distance from the center of the third superlens.

[0287] Figure 8p The results of the simulation provided in Example 5 show the relationship between the distance from the center of the third superlens and the radius of the superlens.

[0288] Figure 8q (a) Plan view, (b) Side view and (c) Perspective view of the fourth superlens provided in Example 5.

[0289] Figure 8r Example 5 illustrates the relationship between the target phase of light transmitted through the fourth superlens and the distance from the center of the fourth superlens.

[0290] Figure 8s The results of the simulation provided in Example 5 show the relationship between the distance from the center of the fourth superlens and the radius of the superlens.

[0291] Figure 8t (a) Plan view, (b) Side view and (c) Perspective view of the fifth superlens provided in Example 5.

[0292] Figure 8u The example 5 illustrates the relationship between the target phase of the light transmitted through the fifth superlens and the distance from the fifth superlens.

[0293] Figure 8v The results of the simulation provided in Example 5 show the relationship between the distance from the center of the fifth superlens and the radius of the superlens.

[0294] Figure 8w The following are (a) plan view, (b) side view, and (c) perspective view of the sixth superlens.

[0295] Figure 8x The relationship between the target phase of the light transmitted through the sixth superlens provided in Example 5 and the distance to the center of the sixth superlens is shown.

[0296] Figure 8y This is the result of the simulation provided in Example 5 regarding the relationship between the distance from the center of the superlens and the radius of the superlens.

[0297] Figure 9a The specification table for line e provided in Example 6.

[0298] Figure 9b The effective focal length table provided for Example 6.

[0299] Figure 9c The surface information table provided for Example 6.

[0300] Figure 9d A diagram illustrating the construction of the imaging optical system provided in Example 6.

[0301] Figure 9e The image showing the chromatic aberration provided in Example 6.

[0302] Figure 9f The metasurface information table provided in Example 6.

[0303] Figure 9g (a) Plan view, (b) Side view and (c) Perspective view of the superlens provided in Example 6.

[0304] Figure 9h The example 6 illustrates the relationship between the target phase of light transmitted through the first superlens and the distance from the center of the first superlens.

[0305] Figure 9i A graph showing the relationship between the radius of the upper surface and the phase in a nanopillar, as provided in Example 6.

[0306] Figure 9j The results of the simulation of the phase of light transmitted through the nanopillars provided in Example 6.

[0307] Figure 9k The results of the simulation of light transmission through the nanopillars provided in Example 6.

[0308] Figure 9l The results of the simulation provided in Example 6 show the relationship between the distance from the center of the first superlens and the radius of the superlens.

[0309] Figure 9m The example 6 illustrates the relationship between the target phase of the light transmitted through the second superlens and the distance from the center of the second superlens.

[0310] Figure 9n The results of the simulation provided in Example 6 show the relationship between the distance from the center of the second superlens and the radius of the superlens.

[0311] Figure 10a The specification table for line e provided in Example 7.

[0312] Figure 10b The effective focal length table provided for Example 7.

[0313] Figure 10cThe surface information table provided for Example 7.

[0314] Figure 10d The aspherical coefficient table provided for Example 7.

[0315] Figure 10e A diagram illustrating the construction of the imaging optical system provided in Example 7.

[0316] Figure 10f The image showing the chromatic aberration provided in Example 7.

[0317] Figure 10g The metasurface information table provided in Example 7.

[0318] Figure 10h (a) Plan view, (b) Side view, and (c) Perspective view of the superlens provided in Example 7.

[0319] Figure 10i The example 7 illustrates the relationship between the target phase of light transmitted through the first superlens and the distance from the center of the first superlens.

[0320] Figure 10j A graph showing the relationship between the radius of the upper surface and the phase in a nanopillar, as provided in Example 7.

[0321] Figure 10k The results of the simulation provided in Example 7 show the relationship between the distance from the center of the first superlens and the radius of the superlens.

[0322] Figure 10l The example 7 illustrates the relationship between the target phase of the light transmitted through the second superlens and the distance from the center of the second superlens.

[0323] Figure 10m The results of the simulation provided in Example 7 show the relationship between the distance from the center of the second superlens and the radius of the superlens. Detailed Implementation

[0324] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this invention.

[0325] Recently, smartphone lenses have adopted more lenses to support anticipated requirements, such as better resolution and larger pixel sizes. Therefore, the necessity of TTL (Time-of-Limit) technology is increasing, making it difficult to reduce its size.

[0326] In this embodiment, in response to the requirement for a shorter TTL, the use of metasurfaces is considered. A metasurface is an artificial surface that possesses optical properties not found in nature. Hereinafter, a metasurface used as a lens is referred to as a superlens. Superlenses are made of subwavelength arrays of nanostructures of various shapes and can form planar lenses. Specifically, a superlens is an artificial composite material with nanostructures. For example, a superlens can have a negative refractive index. Superlenses can be made very thin because they are nanostructures, and the height of the nanostructures is typically at the subwavelength level. Furthermore, superlenses can alter the wavefront phase, and therefore can be used in optical systems to reduce the TTL of the lens system.

[0327] Furthermore, chromatic aberration can also be reduced by using one or more metasurfaces. If light comprises various colors (wavelengths), the light passing through a lens has a different refractive index for each wavelength. Therefore, light with different indices arrives at different points and appears as chromatic aberration in the image, rather than being concentrated at a single point. When the overall optical length of the lens in an optical system is shortened, it becomes difficult to adjust chromatic aberration using conventional lenses (such as plastic lenses). On the other hand, metasurfaces can be used to adjust chromatic aberration by designing nanostructures on them. Therefore, by generating the chromatic aberration of a superlens in the opposite direction, the chromatic aberration can be eliminated. Thus, by combining conventional lenses and superlenses, chromatic aberration can be eliminated.

[0328] Figure 1 This diagram illustrates an exemplary construction of an optical system provided in an embodiment of the present invention. The optical system 1 is used for the camera function of mobile terminals such as mobile phones and smartphones, as well as other electronic devices such as PDAs. The optical system 1 includes multiple optical elements. From the object side (O), the optical elements sequentially include a first lens 102 with positive refractive power, a second lens 104 composed of a superlens, a third lens 108 with negative refractive power, and a fourth lens 110 with positive refractive power. Figure 1 In this design, the first lens 102 and the fourth lens 110 are convex lenses, and the third lens 108 is a concave lens. Each of the first lens 102, the third lens 108, and the fourth lens 110 can be composed of multiple lenses. The first lens 102, the third lens 108, and the fourth lens 110 can be made of materials such as glass and plastic.

[0329] Next, the construction of the second lens 104 will be described. The second lens 104 functions similarly to a diffractive optical element (DOE), which can change light into various patterns and shapes by utilizing the diffraction phenomenon of light.

[0330] The second lens 104 is formed in the shape of a flat plate and includes a metasurface 106 on the object side.

[0331] The metasurface 106 has a nanostructure. The nanostructure can be formed into fine, irregular shapes on the surface of the second lens 104 to provide a predetermined optical path difference (optical phase shift) to adjacent regions. In one embodiment, the nanostructure of the metasurface 106 may consist of nanopillars.

[0332] The diffraction efficiency of a metaface depends on the angle of incidence. If the angle of incidence of the beam relative to the diffraction surface is large, the diffraction efficiency decreases significantly. Therefore, it is desirable to place the metalens on the object side as much as possible. Figure 1 In the example shown, the second lens 104, including the metasurface 106, is located at a second position on the object side among a plurality of lenses. However, it can be located at a first position on the object side.

[0333] Furthermore, although nanostructures are formed in Figure 1 The nanostructure can be formed on one surface of the second lens 104, but it can also be formed on both surfaces of the second lens 104. Furthermore, the nanostructure can be formed on one surface of the object side (O) or image side (I) of the first lens 102, or on both surfaces of the first lens 102. Additionally, although... Figure 1 An optical system comprising only one type of superlens is shown, but the number of superlenses can be increased if desired. In some embodiments, an optical system in which all lenses are superlenses can be configured. Figure 2 A perspective view of the nanopillars provided in this embodiment. Figure 2 In this embodiment, nanopillars 202 are formed on a substrate 204. The substrate 204 corresponds to a second lens 104, which may be made of SiO2. Al2O3 and other materials are also possible. In some embodiments, the nanopillars 202 may be composed of a material selected from Si, TiO2, GaN, and Ln, where Ln represents a rare earth element and is selected from Er, Gd, Nd, Ho, Tm, and Yb. The nanopillars 202 may be made of any other suitable material. In some embodiments, other suitable dielectric materials include those having at least about 40% transmittance in the visible spectrum. For example, other suitable dielectric materials may be selected from oxides (e.g., oxides of aluminum (e.g., Al2O3)), nitrides (e.g., nitrides of silicon (e.g., Si3N4)), sulfides, and pure elements.

[0334] exist Figure 2 In this study, the nanopillar 202 has a columnar structure. However, it can also have shapes such as elliptical pillars, triangular prisms, and square pillars. The diameter of the nanopillar 202 can be designed from 10 to 1000 nm. Furthermore, the height of the nanopillar 202 can be designed from 100 to 2000 nm.

[0335] The second lens 104 may be made of SiO2. In one embodiment, the metasurface 106 comprises SiN.

[0336] As described above, the superlens comprises multiple nanostructures disposed on a substrate. These nanostructures induce an optical phase shift, which depends on the position of individual nanopillars on the substrate. The optical phase shift of the nanostructures defines the phase distribution of the superlens. The optical phase shift can be altered, for example, by changing the diameter of the nanopillars, the height of the nanopillars, the periodicity of the nanostructures, etc.

[0337] Figure 4h (a) a plan view, (b) a side view, and (c) a perspective view of a superlens provided for one embodiment. In one embodiment, the nanostructures constituting the metasurface can be periodically formed on the second lens 104. Preferably, the nanostructures can be formed concentrically, such as... Figure 4h As shown.

[0338] Next, we will refer to Figure 3 Describe the method for manufacturing a superlens.

[0339] Metasurfaces can be fabricated in the same manner as semiconductors. A superlens can be fabricated by the following steps: step (a), preparing a substrate 201 as the material for a second lens 104; step (b), applying a photoresist 202 to the surface of the substrate 201; step (c), patterning the photoresist 202. It also includes: step (d), depositing nanopillars 204; and step (e), removing the photoresist 202.

[0340] In the patterning step (c), a portion of the resist 202 may be removed to expose a portion of the surface of the substrate 201, thereby defining an opening in the resist 202. Then, in the step (d) of depositing the nanopillars 204, a conformal coating is formed, for example by atomic layer deposition (ALD), on the exposed portion of the substrate surface within the resist 202 and the opening.

[0341] In one embodiment, the metasurface containing nanostructures can be formed by a conformal coating. Here, after step (d) of depositing the nanopillars 204, the method may further include step (d') of exposing the resist by removing the top of the conformal coating, for example by etching the conformal coating.

[0342] In step (e) of removing the resist 202, the resist 202 is removed using known photolithography or etching techniques, such as photolithography, electron beam lithography (EBL), DUV lithography using known deep ultraviolet (DUV) (λ = 200 to 300 nm), nanoimprinting, or etching to expose the substrate 201. In the case of photolithography described above, the patterning of the resist 202 is performed on the resist 202. Here, nanoimprinting and DUV lithography are more suitable for large-scale production. Furthermore, EBL is suitable for laboratory testing.

[0343] Next, the properties of nanopillars and superlenses will be described.

[0344] (1) It is necessary to shorten the overall length of the lens mounted on the smartphone. Furthermore, it is difficult to shorten the overall length using conventional optical systems with plastic or glass lenses. Even if the overall length can be shortened, chromatic aberration will increase and performance will degrade.

[0345] In one embodiment, the imaging optical system includes a plurality of optical elements, wherein the plurality of optical elements includes:

[0346] At least one superlens having a nanostructure formed on at least one side;

[0347] Three or more lenses that do not have nanostructures.

[0348] According to this embodiment, a superlens with a nanostructure is inserted into three or more lenses without a nanostructure. Therefore, by generating chromatic aberration in opposite directions through the superlens, chromatic aberration caused by shortening the overall length of the optical system can be eliminated. Since chromatic aberration can be corrected, high optical performance can be ensured while reducing the overall length.

[0349] In one embodiment, the imaging optical system also satisfies the following condition:

[0350] 0.5 <TTL / f<10.0(1-1),

[0351] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the wavelength satisfies the following condition:

[0352] 300nm < wavelength < 700nm.

[0353] Preferably, the imaging optical system also satisfies the following conditions:

[0354] 0.6 <TTL / f<5.0(1-2)。

[0355] More preferably, the imaging optical system also satisfies the following conditions:

[0356] 0.6 <TTL / f<2.0(1-3)。

[0357] In one embodiment, the imaging optical system also satisfies the following condition:

[0358] 0.01<|fconv / fmeta|<0.50(2-1),

[0359] Where fconv is the focal length of the optical system from the image-side optical element (not the superlens closest to the object side) to the optical element closest to the image (the final lens).

[0360] fmeta is the focal length of the superlens that most closely approximates the object.

[0361] The focal length is -0.5 / C1.

[0362] C1 is the second-order coefficient of the phase function of the superlens, and the wavelength satisfies the following condition:

[0363] 300nm < wavelength < 700nm.

[0364] Preferably, the imaging optical system also satisfies the following conditions:

[0365] 0.01<|fconv / fmeta|<0.20(2-2).

[0366] In one embodiment, the superlens is positioned near the aperture of the imaging optical system, and the wavelength satisfies the following condition:

[0367] 300nm < wavelength < 700nm.

[0368] In one embodiment, the imaging optical system also satisfies the following condition:

[0369] 0.4 < |TTLconv / fconv| < 2.0 (3),

[0370] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0371] fconv is the focal length of the optical system from the image-side optical element (not the superlens closest to the object side) to the optical element closest to the image, with the wavelength satisfying the following condition:

[0372] 300nm < wavelength < 700nm.

[0373] In one embodiment, the superlens satisfies the following condition:

[0374] 1.5 <ndmeta<5.0(4-1),

[0375] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0376] Preferably, the superlens satisfies the following conditions:

[0377] 1.8 <ndmeta<3.8(4-2),

[0378] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0379] In one embodiment, the nanostructure consists of nanopillars that satisfy the following condition:

[0380] 2.0 < h / t < 25.0 (5),

[0381] Where h is the height of the nanopillar.

[0382] T is the diameter of the nanopillar, and the wavelength satisfies the following condition:

[0383] 300nm < wavelength < 700nm.

[0384] (2) In another embodiment, the imaging optical system includes a plurality of optical elements, wherein the plurality of optical elements include:

[0385] At least one superlens having a nanostructure formed on at least one side;

[0386] At least one lens that does not have a nanostructure.

[0387] The imaging optical system must satisfy the following conditions:

[0388] 0.5 <TTL / f<10(6-1),

[0389] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

[0390] The incident light wavelength satisfies the following condition:

[0391] 300nm < wavelength < 700nm.

[0392] Preferably, the imaging optical system also satisfies the following conditions:

[0393] 0.6 <TTL / f<5.0(6-2),

[0394] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

[0395] More preferably, the imaging optical system also satisfies the following conditions:

[0396] 0.6 <TTL / f<2.0(6-3)。

[0397] In one embodiment, the imaging optical system also satisfies the following condition:

[0398] 0.01<|fconv / fmeta|<0.50(7-1),

[0399] Where fconv is the focal length of the optical system from the optical element on the image side (not the superlens closest to the object side) to the optical element closest to the image.

[0400] fmeta is the focal length of the superlens that most closely approximates the object.

[0401] The focal length is -0.5 / C1.

[0402] C1 is the quadratic coefficient of the phase function of the superlens.

[0403] Preferably, the imaging optical system also satisfies the following conditions:

[0404] 0.01<|fconv / fmeta|<0.20(7-2).

[0405] In one embodiment, the superlens is positioned near the aperture of the imaging optics system.

[0406] In one embodiment, the imaging optical system also satisfies the following condition:

[0407] 0.4 < |TTLconv / fconv| < 2.0 (8),

[0408] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0409] fconv is the focal length of an optical system from the image-side optical element, rather than the superlens closest to the object side, to the optical element closest to the image.

[0410] In one embodiment, the superlens satisfies the following condition:

[0411] 1.5 <ndmeta<5.0(9-1),

[0412] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0413] Preferably, the superlens satisfies the following conditions:

[0414] 1.8 <ndmeta<3.8(9-2),

[0415] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0416] In one embodiment, the nanostructure consists of nanopillars that satisfy the following condition:

[0417] 2.0 < h / t < 25.0 (10),

[0418] Where h is the height of the nanopillar.

[0419] t is the diameter of the nanopillar.

[0420] (3) In yet another embodiment, the imaging optical system is used for light with wavelengths that satisfy the following conditions:

[0421] 300nm < wavelength < 700nm.

[0422] An imaging optical system includes at least one optical element, wherein the at least one optical element comprises only:

[0423] At least one superlens has a nanostructure formed on at least one side.

[0424] In one embodiment, the imaging optical system consists of only four or more superlenses, each superlens having a nanostructure formed on at least one side.

[0425] In one embodiment, the imaging optical system also satisfies the following condition:

[0426] 0.6 <TTL / f<5.0(11-1),

[0427] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

[0428] Preferably, the imaging optical system also satisfies the following conditions:

[0429] 0.6 <TTL / f<2.0(11-2)。

[0430] In one embodiment, the superlens satisfies the following condition:

[0431] 1.5 <ndmeta<5.0(12-1),

[0432] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0433] Preferably, the metalens satisfies the following conditions:

[0434] 1.8 < ndmeta < 3.8 (12-2),

[0435] where ndmeta is the refractive index of the nanostructure for the d-line.

[0436] In one embodiment, the nanostructure consists of nanocolumns, and the nanocolumns satisfy the following conditions:

[0437] 2.0 < h / t < 25.0 (13),

[0438] where h is the height of the nanocolumn,

[0439] and t is the diameter of the nanocolumn.

[0440] In one embodiment, the imaging optical system satisfies the following conditions:

[0441] 1.0 < TTL / f < 15.0 (14-1), 0.6 < F-number < 1.6 (15-1),

[0442] where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the F-number is the F-number of the imaging optical system,

[0443] The wavelength of the incident light satisfies the following conditions:

[0444] 700 nm < wavelength < 1700 nm.

[0445] Preferably, the imaging optical system satisfies the following conditions:

[0446] 1.5 < TTL / f < 7.0 (14-2), 0.8 < F-number < 1.4 (15-2).

[0447] More preferably, the imaging optical system satisfies the following conditions:

[0448] 2.0 < TTL / f < 4.0 (14-3), 0.9 ≤ F-number < 1.2 (15-3).

[0449] In one embodiment, the imaging optical system further satisfies the following conditions:

[0450] 0.01 < |fconv / fmeta| < 0.50 (16-1),

[0451] where fconv is the focal length of the optical system from the optical element on the image side other than the metalens closest to the object side to the optical element closest to the image,

[0452] fmeta is the focal length of the superlens that most closely approximates the object.

[0453] The focal length is -0.5 / C1.

[0454] C1 is the second-order coefficient of the phase function of the superlens, and the wavelength satisfies the following condition:

[0455] 700nm < wavelength < 1700nm.

[0456] Preferably, the imaging optical system also satisfies the following conditions:

[0457] 0.01<|fconv / fmeta|<0.35(16-2).

[0458] In one embodiment, the superlens is positioned near the aperture of the imaging optical system, and the wavelength satisfies the following condition:

[0459] 700nm < wavelength < 1700nm.

[0460] In one embodiment, the imaging optical system also satisfies the following condition:

[0461] 0.4 < |TTLconv / fconv| < 2.5 (17),

[0462] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0463] Where fconv is the focal length of the optical system from the optical element on the image side (not the superlens closest to the object side) to the optical element closest to the image.

[0464] The wavelength must satisfy the following condition:

[0465] 700nm < wavelength < 1700nm.

[0466] In one embodiment, the superlens satisfies the following condition:

[0467] 1.5 <ndmeta<5.0(18-1),

[0468] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0469] Preferably, the superlens satisfies the following conditions:

[0470] 1.8 <ndmeta<3.8(18-2)。

[0471] In one embodiment, the nanostructure consists of nanopillars that satisfy the following condition:

[0472] 1.0 < h / t < 25.0 (19),

[0473] where h is the height of the nanocolumn,

[0474] and t is the diameter of the nanocolumn.

[0475] (4) According to another embodiment, the imaging optical system includes a plurality of optical elements, where the plurality of optical elements include:

[0476] at least one metalens having nanostructures formed on at least one side;

[0477] at least one lens without nanostructures,

[0478] where the metalens satisfies the following conditions:

[0479] 1.0 < TTL / f < 15.0 (20-1),

[0480] 0.6 < F-number < 1.6 (21-1),

[0481] where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, the F-number is the F-number of the imaging optical system, and the wavelength satisfies the following conditions:

[0482] 700 nm < wavelength < 1700 nm.

[0483] Preferably, the imaging optical system satisfies the following conditions:

[0484] 1.5 < TTL / f < 7.0 (20-2),

[0485] 0.8 < F-number < 1.4 (21-2).

[0486] More preferably, the imaging optical system satisfies the following conditions:

[0487] 2.0 < TTL / f < 4.0 (20-3),

[0488] 0.9 ≤ F-number < 1.2 (21-3).

[0489] In one embodiment, the imaging optical system further satisfies the following condition:

[0490] 0.01 < |fconv / fmeta| < 0.50 (22-1),

[0491] where fconv is the focal length of the optical system from the optical element on the image side other than the metalens closest to the object side to the optical element closest to the image,

[0492] fmeta is the focal length of the superlens that most closely approximates the object.

[0493] The focal length is -0.5 / C1.

[0494] C1 is the quadratic coefficient of the phase function of the superlens.

[0495] Preferably, the imaging optical system also satisfies the following conditions:

[0496] 0.01<|fconv / fmeta|<0.35(22-2).

[0497] In one embodiment, the superlens is positioned near the aperture of the imaging optics system.

[0498] In one embodiment, the imaging optical system also satisfies the following condition:

[0499] 0.4 < |TTLconv / fmeta| < 2.5 (23),

[0500] Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image-forming surface, wherein the superlens is located closest to the object side.

[0501] fconv is the focal length of an optical system from the image-side optical element, rather than the superlens closest to the object side, to the optical element closest to the image.

[0502] In one embodiment, the superlens satisfies the following condition:

[0503] 1.5 <ndmeta<5.0(24-1),

[0504] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0505] Preferably, the superlens satisfies the following conditions:

[0506] 1.8 <ndmeta<3.8(24-2)。

[0507] In one embodiment, the nanostructure consists of nanopillars that satisfy the following condition:

[0508] 1.0 < h / t < 25.0 (25),

[0509] Where h is the height of the nanopillar.

[0510] t is the diameter of the nanopillar.

[0511] (5) In yet another embodiment, the imaging optical system is used for light with a wavelength that satisfies the following condition:

[0512] 700nm < wavelength < 1700nm.

[0513] An imaging optical system includes at least one optical element, wherein the at least one optical element comprises only:

[0514] At least one superlens has a nanostructure formed on at least one side.

[0515] In one embodiment, the imaging optical system consists of only four or more superlenses, each superlens having a nanostructure formed on at least one side.

[0516] In one embodiment, the imaging optical system satisfies the following condition:

[0517] 1.5 <TTL / f<7.0 (26-1),

[0518] 0.8 < F-number < 1.4 (27-1)

[0519] Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and F-number is the F-number of the imaging optical system.

[0520] Preferably, the imaging optical system satisfies the following conditions:

[0521] 2.0 <TTL / f<4.0 (26-2),

[0522] 0.9≤F number<1.2 (27-2).

[0523] In one embodiment, the superlens satisfies the following condition:

[0524] 1.5 <ndmeta<5.0(28-1),

[0525] Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

[0526] More preferably, the superlens satisfies the following conditions:

[0527] 1.8 <ndmeta<3.8(28-2)。

[0528] In yet another embodiment, the nanostructure is composed of nanopillars that satisfy the following conditions:

[0529] 1.0 < h / t < 25.0 (29),

[0530] Where h is the height of the nanopillar.

[0531] t is the diameter of the nanopillar.

[0532] (6) In another embodiment, an imaging device includes:

[0533] Optical devices, including the aforementioned imaging optical system;

[0534] Imaging sensors are used to generate data based on light transmitted through optical devices.

[0535] (7) In yet another embodiment, the electronic device includes an imaging device. The imaging device includes:

[0536] Optical devices, including the aforementioned imaging optical system;

[0537] Imaging sensors are used to generate data based on light transmitted through optical devices.

[0538] In one embodiment, such electronic device can be used for optical applications, such as camera modules, augmented reality (AR) devices, virtual reality (VR) devices, holographic devices, or light field cameras.

[0539] According to the above embodiments, the F-number of the imaging optics in a scaled-down imaging optics system can be adjusted. Therefore, the degree of blurring around the object can be controlled.

[0540] Examples of incident light with wavelengths λ satisfying λ = 700 to 1700 nm can be used with Time-of-Flight (TOF) sensors. The TOF sensor emits near-infrared (NIR) light and receives light reflected from an object via optical elements. The phase difference between the emitted and received light is then digitized and output to the TOF controller. The TOF controller calculates the distance to each pixel from the phase difference data. In this way, 3D images can be captured. According to the above embodiments, the electronic device can reduce the overall optical length of the lens while maintaining the quality of the 3D image.

[0541] Next, an example of an imaging optical system including the aforementioned superlens will be described. In the following embodiments, each nanostructure is formed on one side of each superlens. Furthermore, a filter, such as an IR cutoff filter or a low-pass filter, is located on the far right.

[0542] [Example 1]

[0543] In Example 1, the imaging optical system includes a superlens positioned on the object side of a first lens and seven lenses without nanostructures. The material is SiN. However, SiN is used only as an example; other materials can be used.

[0544] Figure 4a This is the specification sheet for e-line (light with a wavelength of 546.1 nm). Figure 4b This is a table of effective focal distances (EFL). Figure 4c This is a surface information table. Figure 4d This is a table of aspherical coefficients. Figure 4e This is a diagram showing the construction of an imaging optical system. Figure 4f This is a graph with color aberration.

[0545] The phase function Φ of the metasurface is expressed as follows:

[0546]

[0547] Where HCO Cj are the coefficients of the phase function, and r is the radius of the metasurface. Figure 4g This is a table of coefficients for metasurfaces.

[0548] Table 1 shows the specifications of nanopillars (hereinafter referred to as "supernanopillars") for metasurfaces.

[0549] Table 1

[0550] radius 50nm to 140nm interval 500nm high 600nm

[0551] The material of the supernanopillars is SiN with a refractive index of 1.9178.

[0552] Figure 4h The appearance of the superlens provided in Example 1. Figure 4h In the figures, (a) is a top view of the superlens, (b) is a side view of the superlens, and (c) is a perspective view of the superlens. As can be seen from these figures, the nanopillars according to this embodiment are formed concentrically.

[0553] Figure 4i The relationship between the target phase (0 to 2π) of light transmitted through the superlens at a distance (position) from the center O of the superlens is shown. The target phase is the desired phase distribution of the metasurface used in the lens system.

[0554] The desired phase shift can be designed by appropriately setting the radius of each location of the nanopillar. In the design of a superlens, the desired phase distribution from the lens system is determined. Then, the relationship between the phase distribution and the nanopillar radius is found. Therefore, the radius of the nanopillar at a certain location in the superlens can be selected.

[0555] Figure 4j This indicates the radius of the upper surface ( Figure 2 A graph showing the relationship between the "r" in the graph and the phase (0 to 2π) of a nanopillar. Typically, the phase should cover a 2π area. Figure 4j As shown, the phase value increases with the increase of the upper surface radius of the nanopillar.

[0556] Figure 4kIt is the radius of the upper surface of a nanopillar ( Figure 2 (r) and height ( Figure 2 The position specified by "z" in the figure simulates the grayscale result of the phase (–π to π) of light transmitted through the nanopillar. Here, the phase value is represented by grayscale. For example, when Figure 4k When the height z = 0.50 μm, the radius changes abruptly from π to –π when it exceeds 0.12 μm. This indicates that the phase gradually increases. Figure 4k As shown, when the height is constant, the phase increases with the increase of the radius. When the radius and height of the nanopillar change, the phase also changes accordingly.

[0557] Figure 4l The results show the simulated transmittance (%) of light transmitted through a nanopillar at locations specified by the upper surface radius (50 to 130 nm) and height (1000 to 1500 nm). Transmission is expressed in grayscale here. Figure 4l Within the range shown, the nanopillars exhibit high transmittance. The transmittance changes accordingly as the radius and height of the nanopillars vary.

[0558] Figure 4m The results of a simulation provided in one example demonstrate the relationship between the distance (position) from the center O and the radius of the superlens. This relationship between the position within the superlens and the corresponding nanopillar radius can be used to select the nanopillar's position within the superlens.

[0559] Figure 4n The results of this example simulation of the phase change (0 to 2π) of light transmitted through a superlens are shown. Figure 4n In the diagram, the horizontal axis and the vertical axis correspond to... Figure 4h The x and y coordinates are shown. Furthermore, phase changes are represented using grayscale.

[0560] [Example 2]

[0561] In Example 2, the imaging optical system includes a superlens positioned on the object side of a first lens and seven lenses without nanostructures. In this example, the aperture is positioned on the object side of the surface S2 of the fifth lens (conv L4).

[0562] Table 2 shows the specifications of the supernanopillars.

[0563] Table 2

[0564] radius 50nm to 130nm interval 450nm high 500nm

[0565] The material of the supernanopillars is S3iN4. Its refractive index is 2.0531.

[0566] Figures 5a to 5gAn information sheet for the imaging optical system provided in Example 2 is shown. Because... Figures 5a to 5n Corresponding to Figures 4a to 4n Detailed descriptions of the accompanying drawings have been omitted.

[0567] [Example 3]

[0568] In Example 3, the imaging optical system includes a superlens placed on a second lens from the object side and seven lenses that do not have nanostructures.

[0569] Table 3 shows the specifications of the supernanopillars.

[0570] Table 3

[0571] radius 20nm to 110nm interval 400nm high 450nm

[0572] The material of the supernanopillars is GaN with a refractive index of 2.4164.

[0573] Figures 6a to 6g An information sheet for the imaging optical system provided in Example 3 is shown. Figures 6a to 6n Corresponding to Figures 4a to 4n .

[0574] [Example 4]

[0575] In Example 4, the imaging optical system includes a superlens positioned on the object side of a first lens and five lenses without nanostructures. In this example, the aperture is positioned on the object side of the surface S1 of the fourth lens (conv L3).

[0576] Table 4 shows the specifications of the supernanopillars.

[0577] Table 4

[0578] radius 20nm to 110nm interval 400nm high 750nm

[0579] The material of the super nanopillars is TiO2 with a refractive index of 2.652.

[0580] Figures 7a to 7g An information sheet for the imaging optical system provided in Example 4 is shown. Figures 7a to 7k Corresponding to Figures 4a to 4j and Figure 4m .

[0581] [Example 5]

[0582] In Example 5, the imaging optical system includes six superlenses. In the following description, each of the six superlenses is referred to as the first through sixth superlenses from the object side (left side).

[0583] Figures 8a to 8c and Figure 8fAn information table is shown for an imaging optical system provided in Example 5, where all lenses are superlenses. Figure 8a This is the specification table for line e. Figure 8b This is a table of effective focal lengths. Figure 8c This is a surface information table. Figure 8d This is a diagram showing the construction of an imaging optical system. Figure 8e This is a graph with color aberration. Figure 8f This is a metasurface information table.

[0584] Figure 8g (a) to Figure 8g (c) shows the appearance of the first superlens. Figure 8h The relationship between the target phases of light transmitted through the first superlens at a position starting from the center of the first superlens is shown. Figure 8i This is a graph showing the relationship between the radius of the upper surface and the phase of a nanopillar of the first superlens. Figure 8j The results of the simulation show the relationship between the position and the radius starting from the center of the first superlens.

[0585] Figure 8k (a) to Figure 8k (c) shows the appearance of the second superlens. Figure 8l The relationship between the target phases of light transmitted through the second superlens at a position starting from the center of the second superlens is shown. Figure 8m The results of the simulation show the relationship between the position and radius starting from the center of the second superlens.

[0586] Figure 8n (a) to Figure 8n (c) shows the appearance of the third superlens. Figure 8o The relationship between the target phases of light transmitted through the third superlens at a position starting from the center of the third superlens is shown. Figure 8p The results of the simulation show the relationship between the position and radius starting from the center of the third superlens.

[0587] Figure 8q (a) to Figure 8q (c) shows the appearance of the fourth superlens. Figure 8r The relationship between the target phases of light transmitted through the fourth superlens at a position starting from the center of the fourth superlens is shown. Figure 8s The results of the simulation show the relationship between the position and radius starting from the center of the fourth superlens.

[0588] Figure 8t (a) to Figure 8t (c) shows the appearance of the fifth superlens. Figure 8u The relationship between the target phases of light transmitted through the fifth superlens at positions starting from the center of the fifth superlens is shown. Figure 8v The results of the simulation show the relationship between the position and the radius starting from the center of the fifth superlens.

[0589] Figure 8w (a) to Figure 8w (c) shows the appearance of the sixth superlens. Figure 8x The relationship between the target phases of light transmitted through the sixth superlens at positions starting from the center of the sixth superlens is shown. Figure 8y The results show the relationship between the simulated distance from the center of the superlens and the radius of the sixth superlens.

[0590] [Example 6]

[0591] In Example 6, the imaging optical system includes two superlenses. In the following description, each of the two superlenses is referred to as the first and second superlenses from the object side (left side). Furthermore, near-infrared light (λ = 940 nm) is used in this embodiment.

[0592] Figures 9a to 9c and Figure 9f An information table is shown for an imaging optical system in which both lenses are superlenses. Figure 9a This is the specification table for line e. Figure 9b This is a table of effective focal lengths. Figure 9c This is a surface information table. Figure 9d This is a diagram showing the construction of an imaging optical system. Figure 9e This is a graph with color aberration. Figure 9f This is a metasurface information table.

[0593] Figure 9g (a) to Figure 9g (c) shows the appearance of the first superlens. Figure 9h The relationship between the target phases of light transmitted through the first superlens at a position starting from the center of the first superlens is shown. Figure 9i This is a graph showing the relationship between the radius of the upper surface and the phase of a nanopillar of the first superlens. Figure 9j The results were used to simulate the phase of light transmitted through the nanopillars. Figure 9k To simulate the results of light transmission through nanopillars. Figure 9l The results of the simulation show the relationship between the position and the radius starting from the center of the first superlens. Figure 9m The relationship between the target phases of light transmitted through the second superlens at a position starting from the center of the second superlens is shown. Figure 9n The results of the simulation show the relationship between the position and radius starting from the center of the second superlens.

[0594] [Example 7]

[0595] In Example 7, the imaging optical system includes two superlenses and three conventional lenses. In the following description, each of the two superlenses is referred to as the first and second superlenses from the object side (left side). Furthermore, near-infrared light (λ = 940 nm) is used in this embodiment.

[0596] Figures 10a to 10d and Figure 10g An information table is shown for an imaging optical system in which both lenses are superlenses. Figure 10a This is the specification table for line e. Figure 10b This is a table of effective focal lengths. Figure 10c This is a surface information table. Figure 10d This is a table of aspherical coefficients. Figure 8e This is a diagram showing the construction of an imaging optical system. Figure 8f This is a graph with color aberration. Figure 8g This is a metasurface information table.

[0597] Figure 10h (a) to Figure 10h (c) shows the appearance of the first superlens. Figure 10i The relationship between the target phases of light transmitted through the first superlens at a position starting from the center of the first superlens is shown. Figure 10j This is a graph showing the relationship between the radius of the upper surface and the phase of a nanopillar of the first superlens. Figure 10k The results of the simulation show the relationship between the position and the radius starting from the center of the first superlens. Figure 10l The relationship between the target phases of light transmitted through the second superlens at a position starting from the center of the second superlens is shown. Figure 10m The results of the simulation show the relationship between the position and radius starting from the center of the second superlens.

[0598] Tables 5-1 and 5-2 below show the correspondence between the conditional expressions and the examples. In Examples 1 to 5, the wavelength of the incident light is set to 546.1 nm. On the other hand, in Examples 6 and 7, the wavelength of the incident light is set to 940 nm.

[0599] Table 5-1

[0600]

[0601]

[0602] Table 5-2

[0603]

[0604]

[0605] As described above, the imaging optical system provided in the above example can reduce the overall optical length of the lens while maintaining high performance.

[0606] While the above description is merely a specific embodiment of the present invention, it is not intended to limit the scope of protection of the present invention. Any variations or substitutions that are readily conceived by those skilled in the art within the scope of the disclosed technology should fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An imaging optical system, characterized in that, The imaging optical system includes multiple optical elements and satisfies the following conditions: 0.5 <TTL / f<10.0, Where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system. The plurality of optical elements include: At least one superlens has a nanostructure formed on at least one side, the nanostructure being used to compensate for chromatic aberration of the imaging optical system; Three or more lenses, without the aforementioned nanostructure; The imaging optical system also satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.50 Where fconv is the focal length of the optical system, which ranges from the optical element closest to the image side (below the superlens closest to the object side) to the optical element closest to the image side. fmeta is the focal length of the superlens that most closely approximates the object. Wherein, the focal length is –0.5 / C1. Where C1 is the quadratic coefficient of the phase function of the superlens.

2. The imaging optical system according to claim 1, characterized in that, The imaging optical system also satisfies the following conditions: 300 nm < wavelength < 700 nm.

3. The imaging optical system according to claim 2, characterized in that, The imaging optical system also satisfies the following conditions: 0.6 <TTL / f<5.0。 4. The imaging optical system according to claim 3, characterized in that, The imaging optical system also satisfies the following conditions: 0.6 <TTL / f<2.0。 5. The imaging optical system according to any one of claims 1 to 4, characterized in that, The imaging optical system satisfies the following conditions: 300 nm < wavelength < 700 nm.

6. The imaging optical system according to claim 5, characterized in that, The imaging optical system also satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.

20.

7. The imaging optical system according to any one of claims 1 to 6, characterized in that, The superlens is positioned near the aperture of the imaging optical system, and the imaging optical system satisfies the following conditions: 300 nm < wavelength < 700 nm.

8. The imaging optical system according to any one of claims 1 to 7, characterized in that, The imaging optical system also satisfies the following conditions: 0.4 < |TTLconv / fconv| < 2.0 Wherein, TTLconv is the distance from the object-side surface of the optical element on the image side of the superlens to the image forming surface, wherein the superlens is located closest to the object side. fconv is the focal length of an optical system that ranges from the optical element closest to the image side (before the superlens closest to the object side) to the optical element closest to the image side, and the imaging optical system satisfies the following condition: 300 nm < wavelength < 700 nm.

9. The imaging optical system according to any one of claims 1 to 8, characterized in that, The superlens satisfies the following conditions: 1.5 <ndmeta<5.0, Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

10. The imaging optical system according to claim 9, characterized in that, The superlens satisfies the following conditions: 1.8 <ndmeta<3.8, Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

11. The imaging optical system according to any one of claims 1 to 10, characterized in that, The nanostructure is composed of nanopillars, which satisfy the following conditions: 2.0 <h / t<25.0, Where h is the height of the nanopillar. t is the diameter of the nanopillar, and the imaging optical system satisfies the following condition: 300 nm < wavelength < 700 nm.

12. An imaging optical system, characterized in that, It includes multiple optical elements, wherein the multiple optical elements include: At least one metalens, having nanostructures formed on at least one side, the nanostructures being configured to compensate for chromatic aberration of the imaging optical system; At least one lens, without the nanostructures, wherein the imaging optical system satisfies the following conditions: 0.5 < TTL / f < 10, where TTL is the distance from the lens closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system, the wavelength of the incident light satisfies the following conditions: 300 nm < wavelength < 700 nm; wherein the imaging optical system further satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.50, where fconv is the focal length of the following optical system, which is from the optical element closer to the image side than the metalens closest to the object side, to the optical element closest to the image side, fmeta is the focal length of the metalens closest to the object, where the focal length is –0.5 / C1, where C1 is the quadratic coefficient of the phase function of the metalens.

13. The imaging optical system according to claim 12, characterized in that, The imaging optical system further satisfies the following conditions: 0.6 < TTL / f < 5.0, where TTL is the distance from the lens closest to the object side to the imaging point of the imaging optical system, and f is the focal length of the entire imaging optical system.

14. The imaging optical system according to claim 13, characterized in that, The imaging optical system further satisfies the following conditions: 0.6 < TTL / f < 2.

0.

15. The imaging optical system according to any one of claims 12 to 14, characterized in that, The imaging optical system further satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.

20.

16. The imaging optical system according to any one of claims 12 to 15, characterized in that, The metalens is arranged near the aperture of the imaging optical system.

17. The imaging optical system according to any one of claims 12 to 16, characterized in that, The imaging optical system further satisfies the following conditions: 0.4 < |TTLconv / fconv| < 2.0, where TTLconv is the distance from the object side surface of the optical element closest to the image side of the metalens to the image formation surface, where the metalens is closest to the object side, where fconv is the focal length of the following optical system, which is from the optical element closer to the image side than the metalens closest to the object side, to the optical element closest to the image side.

18. The imaging optical system according to any one of claims 12 to 17, characterized in that, The metalens satisfies the following conditions: 1.5 < ndmeta < 5.0, where ndmeta is the refractive index of the nanostructures for the d line.

19. The imaging optical system according to claim 18, characterized in that, The metalens satisfies the following conditions: 1.8 < ndmeta < 3.8, where ndmeta is the refractive index of the nanostructures for the d line.

20. The imaging optical system according to any one of claims 12 to 19, characterized in that, The nanostructures are composed of nanocolumns, and the nanocolumns satisfy the following conditions: 2.0 < h / t < 25.0, where h is the height of the nanocolumns, and t is the diameter of the nanocolumns.

21. The imaging optical system according to claim 1, characterized in that, The imaging optical system satisfies the following conditions: 1.0 < TTL / f < 15.0, 0.6 < F-number < 1.6, where TTL is the distance from the optical element closest to the object side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the F-number is the F-number of the imaging optical system, the wavelength of the incident light satisfies the following conditions: 700 nm < wavelength < 1700 nm.

22. The imaging optical system according to claim 21, characterized in that, The imaging optical system satisfies the following conditions: 1.5 < TTL / f < 7.0, 0.8 < F - number < 1.

4.

23. The imaging optical system according to claim 22, characterized in that, The imaging optical system satisfies the following conditions: 2.0 < TTL / f < 4.0, 0.9 ≤ F - number < 1.

2.

24. The imaging optical system according to claim 1 or any one of claims 21 to 23, characterized in that, The imaging optical system satisfies the following conditions: 700 nm < wavelength < 1700 nm.

25. The imaging optical system according to claim 24, characterized in that, The imaging optical system further satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.

35.

26. The imaging optical system according to claim 1 or any one of claims 21 to 25, characterized in that, The imaging optical system further satisfies the following conditions: 0.4 < |TTLconv / fconv| < 2.5, where TTLconv is the distance from the object - side surface of the optical element closest to the image - side of the superlens to the image - forming surface, and the superlens is positioned closest to the object - side. fconv is the focal length of the following optical system, which is from the optical element closer to the image - side than the superlens closest to the object - side to the optical element closest to the image - side. The imaging optical system satisfies the following conditions: 700 nm < wavelength < 1700 nm.

27. The imaging optical system according to claim 1 or any one of claims 21 to 26, characterized in that, The superlens satisfies the following conditions: 1.5 < ndmeta < 5.0, where ndmeta is the refractive index of the nanostructure for the d - line.

28. The imaging optical system according to claim 27, characterized in that, The superlens satisfies the following conditions: 1.8 < ndmeta < 3.

8.

29. The imaging optical system according to claim 1 or any one of claims 21 to 28, characterized in that, The nanostructure consists of nanocolumns, and the nanocolumns satisfy the following conditions: 1.0 < h / t < 25.0, where h is the height of the nanocolumn, and t is the diameter of the nanocolumn.

30. An imaging optical system, characterized in that, It includes a plurality of optical elements, and the plurality of optical elements include: At least one superlens having nanostructures formed on at least one side, and the nanostructures are used to compensate the chromatic aberration of the imaging optical system; At least one lens without the nanostructures, where the superlens satisfies the following conditions: 1.0 < TTL / f < 15.0, 0.6 < F - number < 1.6, where TTL is the distance from the optical element positioned closest to the object - side to the imaging point of the imaging optical system, f is the focal length of the entire imaging optical system, and the F - number is the F - number of the imaging optical system. The imaging optical system satisfies the following conditions: 700 nm < wavelength < 1700 nm; where the imaging optical system further satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.50, where fconv is the focal length of the following optical system, which is from the optical element closer to the image - side than the superlens closest to the object - side to the optical element closest to the image - side, and fmeta is the focal length of the superlens closest to the object. where the focal length is –0.5 / C1, where C1 is the quadratic coefficient of the phase function of the superlens.

31. The imaging optical system according to claim 30, characterized in that, The imaging optical system satisfies the following conditions: 1.5 < TTL / f < 7.0, 0.8 < F - number < 1.

4.

32. The imaging optical system according to claim 31, characterized in that, The imaging optical system satisfies the following conditions: 2.0 < TTL / f < 4.0, 0.9 ≤ F - number < 1.

2.

33. The imaging optical system according to any one of claims 30 to 32, characterized in that, The imaging optical system further satisfies the following conditions: 0.01 < |fconv / fmeta| < 0.

35.

34. The imaging optical system according to any one of claims 30 to 33, characterized in that, The superlens is arranged near the aperture of the imaging optical system.

35. The imaging optical system according to any one of claims 30 to 34, characterized in that, The imaging optical system also satisfies the following conditions: 0.4 < |TTLconv / fmeta| < 2.5, Wherein, TTLconv is the distance from the object-side surface of the optical element closest to the image side of the superlens to the image forming surface, wherein the superlens is located closest to the object side. fconv is the focal length of an optical system that ranges from the superlens closest to the object side to the optical element closest to the image side.

36. The imaging optical system according to any one of claims 30 to 35, characterized in that, The superlens satisfies the following conditions: 1.5 <ndmeta<5.0, Wherein, ndmeta is the refractive index of the nanostructure for the d-line.

37. The imaging optical system according to claim 36, characterized in that, The superlens satisfies the following conditions: 1.8 <ndmeta<3.8。 38. The imaging optical system according to any one of claims 30 to 37, characterized in that, The nanostructure is composed of nanopillars, which satisfy the following conditions: 1.0 <h / t<25.0, Where h is the height of the nanopillar. t is the diameter of the nanopillar.

39. An imaging device, characterized in that, include: Optical devices, including imaging optical systems according to any one of claims 1 to 38; An imaging sensor for generating data based on light transmitted through the optics.

40. An electronic device, characterized in that, The imaging device includes: Optical devices, including imaging optical systems according to any one of claims 1 to 38; An imaging sensor for generating data based on light transmitted through the optics.

Images