Optical imaging system, optical module and electronic device

Abstract

The invention provides an optical imaging system, an optical module and an electronic device, the system comprises a refracting optical assembly and a diffractive optical assembly which are located on an optical path of incident light, the refracting optical assembly comprises at least one refracting optical lens, the diffractive optical assembly comprises at least one super-structure lens, and the super-structure lens comprises at least one super-structure lens. One of the refractive optical assembly and the diffractive optical assembly is configured to have at least a negative dispersion characteristic of a visible light wave band range, and the other one is configured to have at least a positive dispersion characteristic of the visible light wave band range; the refractive optical assembly and the diffractive optical assembly at least have no chromatic dispersion on light in a visible light wave band range. According to the imaging optical system, the module thickness (TTL), the complexity and the processing difficulty which are lower than those of a traditional optical imaging system can be realized, and meanwhile, a dispersion-free and aberration-free imaging effect which exceeds those of the traditional optical imaging system can be realized.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and more specifically to an optical imaging system, an optical module and an electronic device. Background Art

[0002] Optical technology, especially imaging optical technology, is a key technology in application fields such as 3D vision, artificial intelligence, and smart cars. It can use the characteristics of light, such as reflection, refraction, and interference, to capture and process the three-dimensional information of objects, thereby realizing the perception and understanding of the environment. For example, in the field of 3D vision, optical technology can reconstruct the three-dimensional model of an object from images at different angles or times through methods such as stereoscopic vision, optical flow, and structured light; in the field of artificial intelligence, optical technology can provide rich visual data through sensors such as cameras and lidars for training and testing deep learning models to achieve functions such as object recognition, tracking, and positioning; in the field of smart cars, optical technology can improve the perception accuracy and robustness of autonomous vehicles through the fusion of multiple sensors to cope with complex and dynamic driving environments. Therefore, optical technology plays an indispensable role in these application fields and promotes the development and innovation of related technologies and industries.

[0003] In order to achieve the high-quality imaging effect required by current electronic devices, traditional optical imaging devices often inevitably use multiple refractive optical lenses, which makes the imaging device large in size and heavy in weight, which runs counter to the current development needs of flat, miniaturized, and lightweight electronic devices. In recent years, when the highly-anticipated meta-lenses are used in imaging devices, they are often accompanied by chromatic aberration caused by dispersion. Using meta-lenses alone still cannot achieve the same imaging quality as traditional optical imaging systems.

[0004] Therefore, it is necessary to provide a new optical imaging system, optical module and electronic device to at least partially solve the above technical problems. Summary of the invention

[0005] The present application is proposed to solve at least one of the above problems. Specifically, the present application provides an optical imaging system, the system comprising: a refractive optical component and a diffractive optical component located on the optical path of incident light, the refractive optical component comprising at least one refractive optical lens, the diffractive optical component comprising at least one meta-lens, one of the refractive optical component and the diffractive optical component is configured to have at least a negative dispersion characteristic in the visible light band range, and the other is configured to have at least a positive dispersion characteristic in the visible light band range, or both the refractive optical component and the diffractive optical component are at least dispersion-free for light in the visible light band range.

[0006] Exemplarily, along the propagation direction of the incident light, the refractive optical component is located in front of the diffractive optical component, and the incident light is incident on the refractive optical component and then emitted to the diffractive optical component; or

[0007] The refractive optical component includes a first refractive optical lens and a second refractive optical lens, and the diffractive optical component includes a meta-lens, and the meta-lens is arranged between the first refractive optical lens and the second refractive optical lens; or

[0008] Along the propagation direction of the incident light, the refractive optical component is located behind the diffractive optical component, and the incident light is incident on the diffractive optical component and then emitted to the refractive optical component.

[0009] Exemplarily, along the propagation direction of the incident light, at least part of the refractive optical lenses in the refractive optical component are located in front of the diffractive optical component, the incident light is refracted by the refractive optical component and then incident on the diffractive optical component, the refractive optical component is configured to focus the incident light and then emit it to the diffractive optical component, wherein the field of view angle of the optical imaging system is greater than 100°.

[0010] Exemplarily, the refractive optical component includes a first refractive optical lens and a second refractive optical lens, wherein the aperture of the first refractive optical lens is larger than the aperture of the second refractive optical lens, and light emitted from the first refractive optical lens is incident on the second refractive optical lens.

[0011] Exemplarily, one of the refractive optical component and the diffractive optical component is configured to have negative dispersion characteristics ranging from the visible light band to the mid-to-far infrared band, and the other is configured to have positive dispersion characteristics ranging from the visible light band to the mid-to-far infrared band.

[0012] Exemplarily, the refractive optical lens is one of the following lenses: a spherical optical lens, a Fresnel lens, a free-form surface lens, and a doublet lens.

[0013] Exemplarily, the metalens includes a substrate and a micro-nano structure layer disposed on the substrate, and the micro-nano structure layer includes a plurality of periodically arranged micro-nano structure units.

[0014] Exemplarily, the micro-nano structure unit includes at least one of the following: a square columnar micro-nano structure, a cylindrical micro-nano structure, a fishing net columnar micro-nano structure, an antenna-type micro-nano structure; and / or

[0015] The periodicity of the micro-nano structure unit is based on optical phase modulation.

[0016] The present application also provides an optical module, comprising the aforementioned optical imaging system.

[0017] The present application also provides an electronic device, comprising the optical imaging system and imaging chip as described in any one of the above items, wherein the imaging chip is used to receive the light emitted by the optical imaging system, or comprises the aforementioned optical module.

[0018] The optical imaging system of the present application is composed of a refractive optical lens and a meta-lens, realizing a dispersion-free optical imaging system and improving the imaging effect when used for imaging. Moreover, by adding a meta-lens to the optical imaging system, the optical imaging system can also have the aberration-free and super-resolution characteristics of the meta-lens itself, and compared with the traditional optical imaging system composed of a refractive optical lens, the optical imaging system of the present application reduces the module thickness (TTL), complexity and processing difficulty compared with the traditional optical imaging system due to the introduction of the meta-lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 A schematic diagram of the structure of an optical imaging system according to an embodiment of the present application is shown;

[0021] Figure 2 A schematic diagram of the structure of a meta-lens according to an embodiment of the present application is shown;

[0022] Figure 3 A schematic diagram of the structure of an optical imaging system according to an embodiment of the present application is shown;

[0023] Figure 4 A schematic diagram of the structure of an optical imaging system according to an embodiment of the present application is shown;

[0024] Figure 5 A schematic diagram of the structure of an optical imaging system according to an embodiment of the present application is shown;

[0025] Figure 6 A schematic diagram of the structure of an optical imaging system according to an embodiment of the present application is shown;

[0026] Figure 7 A schematic diagram of the structure of an optical imaging system according to an embodiment of the present application is shown;

[0027] In the attached picture:

[0028] Light source or imaging object 1, refractive optical component 2, first refractive optical lens 21, second refractive optical lens 22, meta-lens 3, substrate 3a, micro-nano structure layer 3b, imaging chip 4. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0030] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0031] It should be understood that the present application can be implemented in different forms and should not be interpreted as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0032] In order to thoroughly understand the present application, a detailed structure will be proposed in the following description to illustrate the technical solution proposed by the present application. The optional embodiments of the present application are described in detail as follows, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0033] Dispersion correction has long been one of the key points in traditional optical design. Traditional lenses are mostly refractive optical lenses. The refractive index of the optical material of the refractive optical lens is not only related to the physical properties of the material itself, but also to the wavelength of the light. For the same optical material, the shorter the wavelength, the higher the refractive index, and the different degrees of deflection of different colored light, resulting in dispersion. Different optical materials also tend to have different dispersions. It is precisely because of the existence of dispersion in optical materials that chromatic aberration is inevitably caused. The traditional optical design to completely correct chromatic aberration requires a complex and bulky optical imaging system, and has strict requirements on the type of optical materials and is difficult to process.

[0034] With the advancement of basic optical theory, lenses have begun to undergo technological innovation from traditional refractive optical lenses to diffractive lenses and even meta-lenses. Among them, meta-lenses, with their free structural design and parameter modulation, mature semiconductor process processing methods, aberration-free and super-resolution optical imaging effects, will become the mainstream direction of future lenses. However, due to the limitations of physical principles, single-piece lenses, whether refractive optical lenses or meta-lenses, will produce dispersion problems. Therefore, through the design and assembly of a small number of refractive optical lenses and meta-lenses, a dispersion-free optical imaging system can be achieved, while having the aberration-free and super-resolution characteristics of the meta-lens itself, forming the next generation of optical imaging systems.

[0035] In view of the existence of the above problems, the present application provides an optical imaging system. Figures 1 to 7 The optical imaging system provided by the present application is described and illustrated, wherein: Figure 1 An optical imaging system according to an embodiment of the present application is shown; Figure 2 A meta-lens according to an embodiment of the present application is shown; Figure 3 An optical imaging system according to an embodiment of the present application is shown; Figure 4 An optical imaging system according to an embodiment of the present application is shown; Figure 5 An optical imaging system according to an embodiment of the present application is shown; Figure 6 An optical imaging system according to an embodiment of the present application is shown; Figure 7 An optical imaging system according to an embodiment of the present application is shown; it is worth mentioning that, under the premise of no conflict, the features of various embodiments of the present application can be combined with each other.

[0036] In one embodiment, Figure 1As shown, the optical imaging system provided by the present application includes: a refractive optical component 2 and a diffractive optical component located on the optical path of the incident light, the refractive optical component 2 includes at least one refractive optical lens, the diffractive optical component includes at least one meta-lens 3, one of the refractive optical component 2 and the diffractive optical component is configured to have at least a negative dispersion characteristic in the visible light band, and the other is configured to have at least a positive dispersion characteristic in the visible light band, or the refractive optical component 2 and the diffractive optical component are both at least dispersion-free for light in the visible light band. Through the mutual compensation between positive dispersion and negative dispersion, the optical imaging system can be made to be dispersion-free, or the refractive optical component 2 itself can be used to achieve dispersion-free, or the structure of the diffractive optical component itself can be used to achieve dispersion-free, so that the optical imaging system is dispersion-free, and the imaging effect when it is used for imaging is improved. Moreover, by adding the meta-lens 3 to the optical imaging system, the optical imaging system can also have the aberration-free and super-resolution characteristics of the meta-lens 3 itself. Compared with the traditional optical imaging system composed of refractive optical lenses, the optical imaging system of the present application reduces the module thickness (TTL), complexity and processing difficulty due to the introduction of the meta-lens 3.

[0037] like Figure 1 As shown, the incident light can be the light emitted by the light source or the imaging object 1, and the light emitted by the imaging object is also the light scattered by the imaging object. Alternatively, the light source can also be a lighting lamp that can emit light, such as an LED light source or a laser light source.

[0038] In one embodiment, Figure 2 As shown, the metalens 3 is a diffractive optical element, and the metalens 3 includes a substrate 3a and a micro-nano structure layer 3b formed on the substrate 3a, wherein the micro-nano structure layer 3b includes a plurality of micro-nano structure units, and the plurality of micro-nano structure units include a plurality of first micro-nano structure units and at least one second micro-nano structure unit (not shown), and the micro-nano structure unit is configured to: split the incident light into a plurality of outgoing light beams, and the at least one second micro-nano structure is used to modulate the high-frequency component of the light wave.

[0039] Furthermore, the substrate 3a may be made of any suitable material, for example, the substrate 3a may include glass, quartz substrate, silicon substrate, diamond substrate, silicon oxide, etc. The first micro-nano structure layer and the second micro-nano structure layer unit may be convex structures located on the surface of the substrate 3a.

[0040] Those skilled in the art can form the micro-nano structure layer 3b corresponding to the optical imaging system described above on the substrate 3a by any suitable method. For example, a polymer material can be coated on the substrate 3a, and then a micro-nano structure can be formed in the polymer by embossing, or the substrate 3a can be etched to form the micro-nano structure layer 3b.

[0041] Exemplarily, the micro-nano structure unit includes at least one of the following: a square columnar micro-nano structure, a cylindrical micro-nano structure, a fishing net columnar micro-nano structure, an antenna-type micro-nano structure, or other and other types of periodic micro-nano structures that can adjust the phase, amplitude and polarization of the light field, wherein the shapes of the micro-nano structure units included in the micro-nano structure layer 3b can be the same, or the micro-nano structure units included in the micro-nano structure layer 3b have different shapes in different regions. When the optical imaging system includes multiple meta-lenses 3, the structures of different meta-lenses 3 can be the same or different.

[0042] In one embodiment, the micro-nanostructure layer 3b includes at least one cylindrical micro-nanostructure with different structures, and the parameters of the cylindrical micro-nanostructure meet the following requirements: the corresponding light wavelength is 400-10 μm, the diameter is 1 / 10-1 / 2 of the light wavelength, the height is 1 / 2 of the light wavelength, the diameter of the structure shows periodic structural changes within a variable range, and the angle between the structural column and the plane of the substrate 3a is 90°±5°.

[0043] In this exemplary embodiment, the micro-nano structure layer 3b is arranged periodically, and its period is a phase modulation period corresponding to the light wavelength of 400-10μm, and the phase modulation effect after the light wavelength is transmitted is formed by periodic changes. The specific parameters are as follows: according to the refractive index of the material, the distance range of the structure required to be arranged corresponding to a π / 4 or π / 8 phase of the corresponding light wavelength is calculated, and each order period of the micro-nano structure should be 1 / 8 or 1 / 16 of a complete 2π phase, and 8 or 16 periods together constitute a complete 2π phase structure.

[0044] In this exemplary embodiment, the metalens 3 is a transmission type metalens, and the incident light is incident from one side of the micro-nano structure layer 3 b and is emitted from the substrate 3 a .

[0045] In the present application, a refractive optical lens refers to an optical element that uses the refraction phenomenon to change the propagation direction of light. Optionally, whether the dispersion of the refractive optical lens is negative depends on the material and shape of the lens. In general, a refractive optical lens has positive dispersion, that is, the focal length of red light is the longest, the focal length of purple light is the shortest, and the focal length of the intermediate color is between the two. This is because the refractive index of light of different colors in the lens is different, resulting in different refraction angles of light of different colors, thereby causing color distortion of imaging. However, there are also some special lenses that can achieve negative dispersion, that is, the focal length of red light is the shortest, the focal length of purple light is the longest, and the focal length of the intermediate color is between the two. These lenses are usually composed of lenses of different materials and refractive indices, such as double glued sheets or triple glued sheets. Double glued sheets are formed by gluing a convex lens with positive dispersion and a concave lens with negative dispersion, and triple glued sheets are formed by gluing a convex lens with positive dispersion and two concave lenses with negative dispersion. These lenses can eliminate or reduce dispersion by using the difference in different materials and curvatures.

[0046] In some embodiments, the refractive optical lens may include one of the following lenses: a spherical optical lens, a Fresnel lens, a free-form lens, and a doublet lens.

[0047] Among them, spherical optical lens refers to a transparent body composed of two spherical surfaces or a spherical surface and a plane, which can focus or diverge the incident light. According to the shape and function of the lens, it can be divided into convex lens and concave lens. Convex lens can make parallel light converge at the focus to form a real image; concave lens can make parallel light diverge to form a virtual image.

[0048] Among them, Fresnel lens: refers to a thin sheet composed of a series of concentric rings. The thickness and curvature of each ring are designed according to the Fresnel formula to simulate the effect of a complete spherical lens. The advantages of Fresnel lens are light weight, small size and low cost, and the disadvantages are large chromatic aberration and diffraction loss. Free-form surface lens: refers to a transparent body of any shape that is not constrained by a sphere or other regular surfaces, which can achieve more complex and precise light control. Free-form surface lens is an optical lens without rotational symmetry, and its surface can be randomly combined by asymmetric, irregular, and complex free-form surfaces. Free-form surface lenses can achieve functions that traditional optical lenses cannot achieve, such as reducing the number of components in the optical system, improving the field of view and imaging quality, and realizing personalized design.

[0049] A doublet lens is a lens formed by gluing two lenses together. This combination lens formed by two lenses has a short focal length, a large magnification and good imaging quality.

[0050] The dispersion of a spherical optical lens refers to the different focal lengths of different colors of light due to the different refractive indices of light in the lens, which causes color distortion in the image. This phenomenon is also called chromatic aberration, and is an aberration that exists in all spherical lenses. Since the lens cannot focus all colors of light on the same focal plane, the size and position of the image formed by each color of light are different. This effect is called chromatic aberration magnification. Spherical lenses have positive dispersion, that is, the focal length of red light is the longest, the focal length of violet light is the shortest, and the focal length of intermediate colors is between the two. The dispersion of a Fresnel lens is positive, that is, the focal length of red light is the longest, the focal length of violet light is the shortest, and the focal length of intermediate colors is between the two. This is because the Fresnel lens is a diffraction lens, and its focusing effect is determined by the diffraction phenomenon of light waves, and light waves of different colors have different wavelengths and diffraction angles. The dispersion of a Fresnel lens is much larger than that of a refractive optical lens.

[0051] It is worth mentioning that when the refractive optical component 2 includes a plurality of refractive optical lenses, different refractive optical lenses may be lenses of different types, or lenses of the same type, and the specific selection may be reasonable according to actual needs.

[0052] In the present application, the number of refractive optical lenses included in the refractive optical component 2 can be any suitable number, and the number of meta-lenses 3 included in the diffractive optical component can be any suitable number, which can be reasonably set according to actual needs. In one example, Figure 1 As shown, the optical imaging system may include a refractive optical lens and a meta-lens 3, and the light emitted from the refractive optical lens is incident on the meta-lens 3. For example, the micro-nano structure layer 3b of the meta-lens 3 is located on the light incident side, that is, the refractive optical lens is located between the light source / imaging object 1 and the meta-lens 3, and the light emitted from the meta-lens 3 is incident on the imaging chip 4. The refractive optical lens can play a role in beam contraction. In another example, the optical imaging system may include a refractive optical lens and a meta-lens 3, and the light emitted from the meta-lens 3 is incident on the refractive optical lens, that is, the meta-lens 3 is located between the refractive optical lens and the light source / imaging object 1, and the light emitted from the refractive optical lens is incident on the imaging chip 4. In order to achieve dispersion-free, the refractive optical lens in this embodiment has negative dispersion characteristics for light wavelengths ranging from visible light (400-720nm) to mid- and far-infrared bands (720nm-10um), and the metalens 3 has positive dispersion characteristics for light wavelengths ranging from visible light (400-720nm) to mid- and far-infrared bands (720nm-10um). The refractive optical lens and the metalens 3 compensate each other, so that the optical imaging system can achieve dispersion-free and chromatic aberration-free focusing at least within the visible light band, thereby improving the imaging effect.

[0053] In one embodiment, Figure 3As shown, the optical imaging system provided by the present application includes: 2 refractive optical lenses and 1 meta-lens 3, wherein 1 refractive optical lens 2 and 1 meta-lens 3 are sequentially arranged along the optical axis from the object side to the image side, that is, along the optical path of the incident light, 2 refractive optical lenses and 1 meta-lens 3 are arranged between the light source / imaging object 1 and the imaging chip 4, wherein the two refractive optical lenses may include a first refractive optical lens 21 and a second refractive optical lens 22, optionally, the first refractive optical lens 21 and the second refractive optical lens 22 may have the same size and be coaxially arranged, and in some embodiments, the first refractive optical lens 21 and the second refractive optical lens 22 may also have different sizes, or different types of lenses may be used. Continue to refer to Figure 1 , light is incident from the light source or imaging object 1 along the optical axis to the imaging chip 4; wherein the meta-lens 3 has negative dispersion characteristics to produce negative chromatic aberration, and the first refractive optical lens 21 and the second refractive optical lens 22 have positive dispersion characteristics to produce positive chromatic aberration, and by optimizing the distance between the first refractive optical lens 21 and the second refractive optical lens 22 and the meta-lens 3 in the optical path, as well as the parameters of the meta-lens 3 and the first refractive optical lens 21 and the second refractive optical lens 22 in the optical imaging system, the above-mentioned refractive optical lens and the meta-lens produce equal and opposite chromatic aberrations in the working band, thereby achieving the purpose of eliminating dispersion and chromatic aberration in the optical imaging system. The above-mentioned refractive optical lens is not limited to spherical lenses, but can also be lenses of other shapes.

[0054] The front and rear positions of the refractive optical component 2 and the diffractive optical component on the optical path of the incident light can be reasonably set according to the actual imaging needs. In one example, along the propagation direction of the incident light, the refractive optical component 2 is located in front of the diffractive optical component, and the incident light is incident on the refractive optical component 2 and then emitted to the diffractive optical component. Specifically, for example Figure 1 , Figure 4 , Figure 6 and Figure 7 As shown, along the propagation direction of the optical path of the incident light, the refractive optical lens is located in front of the meta-lens 3, that is, the refractive optical lens is closer to the light source or imaging object 1 than the meta-lens 3. The refractive optical lens can play a role in converging or collimating the incident light and then incident on the meta-lens 3, which can achieve imaging with a large field of view, wherein the large field of view can refer to a field of view of not less than 100°, or even a field of view of not less than 120°. For another example, along the propagation direction of the optical path of the incident light, the meta-lens 3 is located in front of the refractive optical lens, that is, the meta-lens 3 is closer to the light source or imaging object 1 than the refractive optical lens.

[0055] In some examples, such as Figure 3As shown, the refractive optical component 2 includes a first refractive optical lens 21 and a second refractive optical lens 22 , and the diffractive optical component includes a meta-lens 3 , and the meta-lens 3 is arranged between the first refractive optical lens 21 and the second refractive optical lens 22 .

[0056] In other examples, along the propagation direction of the incident light, the refractive optical component 2 is located behind the diffractive optical component, and the incident light is incident on the diffractive optical component and then emitted to the refractive optical component 2, for example. Figure 5 As shown, the refractive optical component 2 includes a first refractive optical lens 21 and a second refractive optical lens 22, and the diffractive optical component includes a meta-lens 3. The meta-lens 3 is arranged behind the first refractive optical lens 21 and the second refractive optical lens 22, that is, the incident light passes through the first refractive optical lens 21 and the second refractive optical lens 22 in sequence and then enters the meta-lens 3.

[0057] It is worth mentioning that, although the drawings mainly show the case where the optical imaging system has 1 refractive optical lens and 1 meta-lens, or 2 refractive optical lenses and 1 meta-lens, it is conceivable that it may also include more than two refractive optical lenses, and / or, it may also include more than 1 meta-lens. For example, it may include 3 refractive optical lenses and 2 meta-lenses, and the positions of the 3 refractive optical lenses and the 2 meta-lenses may be arbitrarily arranged on the optical path of the incident light.

[0058] The following will refer to Figure 6 and Figure 7 The optical imaging system provided in the present application is further described and illustrated.

[0059] In some embodiments, the optical imaging system provided by the present application has a field of view greater than 100°, and the optical imaging system includes: a refractive optical component 2 and a diffractive optical component, the refractive optical component 2 includes at least one refractive optical lens, and the diffractive optical component includes at least one meta-lens 3. The refractive optical component 2 can also have a wide-angle imaging effect, along the propagation direction of the incident light, at least part of the refractive optical lenses in the refractive optical component 2 are located in front of the diffractive optical component, the incident light is refracted by the refractive optical component 2 and then incident on the diffractive optical component, the refractive optical component 2 is configured to focus the incident light and then emit it to the diffractive optical component, wherein the field of view of the refractive optical component 2 is greater than 100°, and further, its field of view can be greater than 120°, for example Figure 6 and Figure 7As shown, a first refractive optical lens 2121, a second refractive optical lens 22 and a meta-lens 3 are arranged in sequence along the optical axis from the object side to the image side. The aperture of the first refractive optical lens 21 is larger than that of the second refractive optical lens 22. The first refractive optical lens 21 and the second refractive optical lens 22 are used to converge the light from the light source or the imaging object 1 in a large field of view into the imaging field of view of the meta-lens 3.

[0060] In particular, the refractive optical lens in this embodiment has a wide-angle imaging effect. Through the interaction of the two refractive optical lenses, the light from the light source or the imaging object 1 in a large field of view is focused into the imaging field of view of the meta-lens, thereby obtaining a dispersion-free optical imaging system with a large field of view.

[0061] The field of view angle refers to the angle formed by the two edges of the maximum range of the image of the measured object that can pass through the refractive optical component 2, such as the refractive optical lens, in the optical imaging system. Its size determines the field of view of the optical imaging system.

[0062] The definition of the aperture of a refractive optical lens refers to the effective diameter of the optical element, that is, the maximum range of light that can pass through. The aperture of a refractive optical lens determines the luminous flux and numerical aperture of the optical element, thereby affecting the brightness and resolution of the optical element. The numerical aperture refers to the product of the sine value of the half-apex angle of the maximum conical light beam that the optical element can receive or emit and the refractive index of the medium, which is expressed by the formula: NA = nsinα, where n is the refractive index of the medium and α is the half-apex angle.

[0063] Continue to refer Figure 6 , the light source or imaging object 1 is arranged on the same optical axis as the first refractive optical lens 21, the second refractive optical lens 22, the meta-lens 3 and the imaging chip 4, and the light from the light source or imaging object 1 passes through the first refractive optical lens 21 and the second refractive optical lens 22 in sequence along the optical path and is incident on the imaging field angle of the meta-lens. Figure 7 The figure shows the imaging condition of the optical imaging system when the light source or imaging object 1 deviates from the optical axis. Figure 7 It can be seen that when the light source or the imaging object 1 deviates from the optical axis, it can also be imaged on the imaging chip 4 after passing through the optical imaging system.

[0064] It is worth mentioning that Figure 6 and Figure 7Only the case with two refractive optical lenses is shown, but it can be understood that in some embodiments, the wide-angle function can also be achieved by only one or more refractive optical lenses. In other embodiments, in addition to the partial refractive optical lens arranged in front of the diffractive optical component, the diffractive optical component also includes another partial refractive optical lens, such as at least one third refractive optical lens. The at least one third refractive optical lens can be arranged behind the meta-lens. The light emitted from the meta-lens enters the third refractive optical lens and then transmits, and finally enters the imaging chip 4 for imaging.

[0065] In summary, compared with the traditional optical imaging system, the optical imaging system of the present application is composed of a refractive optical lens and a meta-lens, realizing a dispersion-free optical imaging system, and improving the imaging effect when used for imaging. Moreover, by adding a meta-lens to the optical imaging system, the optical imaging system can also have the aberration-free and super-resolution characteristics of the meta-lens itself, and compared with the traditional optical imaging system composed of refractive optical lenses, the optical imaging system of the present application has reduced the module thickness (TTL), complexity and processing difficulty compared with the traditional optical imaging system due to the introduction of the meta-lens, and has a simple structure and the technical advantage of miniaturization, which can meet the needs of achromatic lenses in various fields.

[0066] Furthermore, the present application also provides an optical module, which may include the aforementioned optical imaging system. For example, in addition to the aforementioned optical imaging system, the optical module may also include a focusing element for achieving zooming and focusing, etc.

[0067] Furthermore, the present application also provides an electronic device, which includes the aforementioned optical imaging system and an imaging chip 4, wherein the imaging chip 4 is used to receive light emitted by the optical imaging system, or includes the aforementioned optical module.

[0068] The imaging chip 4 may include an image sensor, which is a device that can capture and convert light into electrical signals, which can be used to form an image. There are two main types of imaging sensors: charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS). CCD sensors use a global shutter to start and stop the exposure of all pixels at the same time, which is suitable for scenes with fast movement. CMOS sensors use a rolling shutter to start and stop the exposure of each row of pixels in sequence, which is suitable for scenes with low power consumption and high frame rate.

[0069] For example, the basic structure of an image sensor consists of an array of many tiny light-sensitive elements, each of which is called a pixel. Each pixel measures the intensity and color of the light falling on it and produces a corresponding voltage or digital value. The number and size of pixels determine the resolution and sensitivity of the imaging sensor.

[0070] The electronic device may be any device that needs to have an optical imaging system, and for example, the electronic device may include: security equipment, terminal equipment, mobile platform equipment, etc. The terminal equipment may include but is not limited to mobile phones, tablet computers, notebooks, desktop computers, VR / AR glasses, etc., and the mobile platform equipment may include but is not limited to vehicles, aircraft, ships, robots, etc., wherein the vehicle may also be an unmanned vehicle, and the aircraft may also be a drone, etc.

[0071] Since the electronic device provided in the present application has the aforementioned optical imaging system, it has the same advantages as the aforementioned optical imaging system.

[0072] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0073] It should be noted that the above embodiments illustrate rather than limit the present application, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation to the claims. The present application may be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

Claims

1. An optical imaging system, characterized in that: The system includes: a refractive optical component and a diffractive optical component located on the optical path of the incident light, the refractive optical component includes at least one refractive optical lens, the diffractive optical component includes at least one meta-lens, one of the refractive optical component and the diffractive optical component is configured to have negative dispersion characteristics at least in the visible light band range, and the other is configured to have positive dispersion characteristics at least in the visible light band range, or the refractive optical component and the diffractive optical component are both dispersion-free for light at least in the visible light band range.

2. The system according to claim 1, characterized in that Along the propagation direction of the incident light, the refractive optical component is located in front of the diffractive optical component, and the incident light is incident on the refractive optical component and then emitted to the diffractive optical component; or The refractive optical component includes a first refractive optical lens and a second refractive optical lens, and the diffractive optical component includes a meta-lens, and the meta-lens is arranged between the first refractive optical lens and the second refractive optical lens; or Along the propagation direction of the incident light, the refractive optical component is located behind the diffractive optical component, and the incident light is incident on the diffractive optical component and then emitted to the refractive optical component.

3. The system according to claim 1, characterized in that Along the propagation direction of the incident light, at least part of the refractive optical lenses in the refractive optical component are located in front of the diffractive optical component, and the incident light is refracted by the refractive optical component and then incident on the diffractive optical component, and the refractive optical component is configured to focus the incident light and then emit it to the diffractive optical component, wherein the field of view angle of the optical imaging system is greater than 100°.

4. The system according to claim 3, characterized in that The refractive optical component includes a first refractive optical lens and a second refractive optical lens, wherein the aperture of the first refractive optical lens is larger than the aperture of the second refractive optical lens, and light emitted from the first refractive optical lens is incident on the second refractive optical lens.

5. The system according to any one of claims 1 to 4, characterized in that One of the refractive optical component and the diffractive optical component is configured to have negative dispersion characteristics ranging from the visible light band to the mid-to-far infrared band, and the other is configured to have positive dispersion characteristics ranging from the visible light band to the mid-to-far infrared band.

6. The system according to any one of claims 1 to 4, characterized in that The refractive optical lens is one of the following lenses: a spherical optical lens, a Fresnel lens, a free-form surface lens and a doublet lens.

7. The system according to any one of claims 1 to 4, characterized in that The meta-lens includes a substrate and a micro-nano structure layer disposed on the substrate, and the micro-nano structure layer includes a plurality of periodically arranged micro-nano structure units.

8. The system according to claim 7, characterized in that The micro-nano structure unit includes at least one of the following: a square columnar micro-nano structure, a cylindrical micro-nano structure, a fishing net columnar micro-nano structure, an antenna-type micro-nano structure; and / or The periodicity of the micro-nano structure unit is based on optical phase modulation.

9. An optical module, characterized in that: Comprising the optical imaging system as claimed in any one of claims 1 to 8.

10. An electronic device, characterized in that: It comprises the optical imaging system and imaging chip as described in any one of claims 1 to 8, wherein the imaging chip is used to receive light emitted by the optical imaging system, or it comprises the optical module as described in claim 9.

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