The present disclosure relates to a field of optical image, in particular to an optical system and an imaging device.
With the growth of the requirements of filming for users, more and more imaging devices has been set in electronic devices.
With the growth of the imaging quality for imaging device, the optical system in the imaging device cannot satisfy the requirements of larger aperture slots and smaller total track length (TTL) in the prior art.
Therefore, there is an urgent need for an optical system can satisfy the requirements of larger aperture slot and smaller total track length to achieve the electronic miniaturization and lightweight.
In order to solve the above technical problem that the miniaturization of the projection system is limited by the number of lenses and the volume of the lens, an optical system and an imaging device are provided according to the present application.
In the first aspect, an optical system is provided, the optical system including seven optical elements, wherein in order from an object side to an image side, the seven optical elements comprise: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens;
In one embodiment, the second lens is the metalens, and the other optical elements are aspheric optical lenses; and the first lens has a positive focal power;
In one embodiment, the first lens satisfies the following condition:
In one embodiment, the optical system satisfies the following condition:
In one embodiment, the optical system satisfies the following condition:
In one embodiment, the optical system satisfies the following condition:
In one embodiment, a curvature radius of the image-side surface of the seventh lens is greater than 0.
In one embodiment, the first lens satisfies the following condition:
In one embodiment, the metalens comprises a substrate and a nanostructured layer; and the nanostructured layer is set on at least one side of the substrate;
In one embodiment, the period of the nanostructures in any nanostructured layers is greater than or equal to 0.3λc, and is less than or equal to 2λc;
In one embodiment, a height of the nanostructures in any nanostructured layer is greater than or equal to 0.3λc, and is less than or equal to 5λc;
In one embodiment, the plurality of nanostructures are polarization-independent structures.
In one embodiment, the polarization-independent structures comprise cylinder structures, hollow structures, cylindrical structures, round-hole structures, hollow-round-hole structures, square column structures, square hole structures, hollow square column structures and hollow square hole structures.
In one embodiment, the second lens further comprises an antireflection film;
In one embodiment, a wide spectrum phase of a unit cell in the nanostructured layer satisfies:
In one embodiment, the metalens includes at least two nanostructured layers; the nanostructures in any adjacent nanostructured layer are non-coaxial along the direction parallel with the substrate.
In the second aspect, a manufacturing method for a metalens is provided, wherein the method is used to manufacture the metalens of the optical system, and the manufacturing method includes:
In one embodiment, the manufacturing method further comprises:
In the third aspect, an imaging device is provided, wherein the imaging device comprises the optical system claimed as claim 1 and an image sensor; the image sensor is set on the image plane of the optical system.
In one embodiment, the electronic device include the imaging device.
The optical system includes seven optical elements of at least one metalens and several aspheric optical lenses provided by the present application, and the optical system satisfies the requirements that F number is less than 2 and TTL is less than 6 mm, which improves the miniaturization and lightweight of the optical system.
The manufacturing method provided by the present embodiment, the structure of the metalens including at least one nanostructured layer is realized by the manufacturing method, which improves the aspect ratio of nanostructures and increases the freedom degree of the design of the metalens.
Other features and advantages of the present application will become apparent by the detailed description below, or will be acquired in part by the practice of the present application.
It should be understood that the above description is general, and the detailed description described below is exemplary only, and will not limit this application.
In order to explain embodiments of the present disclosure or the prior art more clearly, drawings used in the description of the embodiments, or the prior art will be briefly explained below. Obviously, the following drawings are merely for exemplary and explanatory purposes. It is understood by those skilled in the art that without paying any creative efforts, other drawings are available based on the following drawings.
The application is more comprehensively described below with reference to the drawings, and the embodiments are shown in the drawings. However, the present application may be implemented in many different ways and should not be construed as limited to the embodiment described herein. Instead, these embodiments are provided such that the application will be exhaustive and complete, and will fully communicate the scope of the application to those skilled in the art. The same attached drawing marks throughout indicate the same components. Furthermore, in the drawings, the thickness, ratio and size of the components are enlarged to clearly illustrate.
The term used herein is used only for the purpose of describing the specific embodiment and is not intended to be a limitation. The “one”, “a single”, “the”, “this”, “one” and “at least” used in this application do not represent a limitation on quantity, but are intended to include both singular and plural. For example, “one part” has the same meaning as “at least one part” unless the context clearly indicates otherwise. “At least one” should not be interpreted as limiting to the quantity “one”. “Or” means “and/or”. The term “and/or” includes any and all combinations of one or more of the associated listed items.
Unless otherwise limited, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the field. The terms defined in a jointly used dictionary shall be construed to have the same meaning as those defined in the relevant technical context, and are not interpreted in an idealized or too formal meaning, unless clearly defined in the specification.
The meaning of “include” or “comprise” specifies the nature, quantity, steps, operation, parts, parts, or combinations thereof, but does not exclude other nature, quantity, steps, operation, parts, parts, or a combination of them.
This application describes the implementation with reference to the section diagram as an idealized embodiment. Thus, relative to illustrated shape changes as a result of, for example, manufacturing technique and/or tolerance. Therefore, the embodiments described herein should not be interpreted to be limited to specific shapes of the region as shown herein, but should include deviations from shapes due to fabrication. For example, regions shown or described as flat may typically have coarse and/or non-linear characteristics. Also, the sharp angles shown can be rounded. Thus, the regions shown in the figure are schematic in nature and their shapes are not intended to show the precise shape of the area and are not intended to limit the scope of the claim.
One embodiment according to the present application will be described with reference to the accompanying drawings below.
In the proceeding of miniaturization of optical system, it is difficult for the optical system including traditional plastic lens to make breakthroughs in thickness and large curvature radius due to the limitation of injection molding technology. Thus, the thickness, intervals between the lenses, and TTL for the optical system with seven lenses is difficult to break through. On the other hand, there are only about ten optional materials for plastic lenses, which limits the freedom of the aberration correction of the optical system. At present, although the hybrid lens of glass resin solves the problems such as chromatic aberration to a certain extent, the injection molding process still greatly hinders the miniaturization and lightweight of the optical system. Today, the optical system requires an enormous effort even for every 1 millimeter of total system length reduction. Because the pixels of optical system in imaging device such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) are increasingly higher, and the pixel size of optical system in imaging device such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) is increasingly larger, the more difficult the matching optical system to meet the requirements of large aperture and small TTL.
In the first aspect, an optical system is provided in the present application, as shown from
The present application provides an optical system, the optical system with the seven optical elements can satisfy a larger aperture slot (that is, a smaller F number) and smaller TTL at the same time. And a ratio of an absolute value of the focal length of the metalens to an absolute value of the focal length of the optical system is less than or equal to 45, which is beneficial to enhance the aberration correction ability of the optical system and improves the design freedom of the optical system. The aspheric surface has a point of inflection, which is beneficial to reduce the effective radius of the first aspheric refractive lens and the second aspheric refractive lens from the image side to the object side, thus reducing the volume of the optical system, so as to make the optical system apply to the compact imaging device.
The above settings can enhance the ability of imaging to make the optical system to cooperate with the pixel size, resolution, or incident angle of the chief ray with the sensor, and the optical system has enough design freedom in the specifications of the lens surface, so as to achieve design specifications requirements successfully, such as controlling lens size. It should be noted that only a part of optional structure of the optical system are shown from
Further, in the optical system of the present application, the second lens 20 is the metalens, and other lenses of the optical system are aspheric refractive lens. And the first lens 10 has a positive focal power, and an object side of the first lens 10 is a convex surface; a curvature radius of the object-side of the third lens 30 is positive; the fifth lens 50 has positive focal power; a curvature radius of the object-side of the sixth lens 60 is positive. The focal power of the fourth lens 40 and the seventh lens 70 may be selected according the design requirements of the optical system.
According to the embodiment of the present application, the fifth lens 40 satisfies the conditions as follows:
Wherein R4O is a curvature radius of the object-side surface of the fourth lens 40; R4i is a curvature radius of the image-side surface of the fourth lens 40. Rno and Rni are used to represent the curvature radius of object-side surface and each image-side surface of each lens. And n is an arrangement of the lenses in order from the object-side to the image side, o represents the object side and i represents the image side.
According to the embodiment of the present application, optionally, the curvature radius of the image-side surface of the seventh lens 70 is greater than 0.
According to the embodiment of the present application, optionally, the first lens 10 further satisfies the condition (3):
In an optional embodiment, the optical system further satisfies condition (4) provided by the present embodiment:
In an optional embodiment, the optical system further satisfies condition (5) provided by the present embodiment:
Preferably, the first lens 10 further satisfies:
It should be understood that the optical system provided by the embodiment of the present application, the aspheric refractive lens may be made of an optical glass, such as crown brand glass, flint glass, quartz glass; the aspheric refractive lens may be made of various kinds of optical plastics, such as APL5514, OKP4HT. Preferably, the aspheric refractive lens may use optical plastic to achieve low cost and mass production through the injection molding process.
Next, the metalens (that is, the second lens 20) provided in this application embodiment is described in
Specifically, the metalens is a kind of the metasurface, and the metasurface modulates the phase, amplitude and polarization of the incident lights by the sub-wavelength nanostructures arranged on the metasurface.
According to the embodiment of the present application, optionally, the period of the nanostructures in any nanostructured layers is greater than or equal to 0.3λc, and is less than or equal to 2λc; and λc is a central wavelength of the second lens at the working waveband.
According to the embodiment of the present application, optionally, a height of the nanostructures in any nanostructured layer is greater than or equal to 0.3λc, and is less than or equal to 5λc; and λc is a central wavelength of the second lens at the working waveband.
In some optional embodiments of the present application, as shown in
As shown in
Optionally, the wide-spectrum phase of unit cell 203 and the working waveband of the metalens also satisfy:
r is a radial coordinates of the metalens; r0 is a distance between any position on the metalens and the center of the metalens; λ is a working wavelength of the metalens.
In one embodiment, the nanostructures 2021 provided by the present embodiment may be polarization-independent structures, and the polarization-independent structures apply a propagation phase to the incident lights. The embodiments as shown in
Preferably, as shown in
In one embodiment, “a” to “d” in
According to the embodiment of the present application, in
In one optional embodiment, as shown in
According to the embodiment of the present application, the extinction coefficient of the substrate 201 is less than 0.01. For example, the substrate 201 may be made of molten quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon or hydrogenated amorphous silicon. In one embodiment, when the working waveband of the metalens is a visible waveband, the substrate 201 may be made of molten quartz, quartz glass, crown glass, flint glass, sapphire or alkaline glass. In an optional embodiment, the material of the nanostructures 2021 is different from the material of the substrate 201. Optionally, the filler material 2022 is the same as the material of the substrate 201. Optionally, the filler material 2022 is different from the material of the substrate 201.
It should be understood that in some optional embodiments of the present application, the filler material 2022 is of the same material as the nanostructure 2021. In some optional embodiments of the present application, the filler material 2022 is different from the material of the nanostructure 2021. In one embodiment, the filler material 2022 is made of a high transmittance material with an extinction coefficient less than 0.01 at the working waveband. In one embodiment, the filler material 2022 may be made of molten quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, or hydrogenated amorphous silicon.
Optionally, the effective refractive index range of the metalens provided by the present application embodiment is less than 2. The effective refractive index range is the maximum refractive index of the metalens minus its minimum refractive index. According to the embodiment of the present application, the phase of the metalens provided by the embodiment of the present application also meets formula (7):
Optionally, the real phase of the metalens provided by the present application can match with the ideal theoretical phase, that is, the matching degree of the wide spectrum of the metalens satisfies the formula (8) as follows:
Furthermore, the aspheric surfaces of the aspheric refractive lenses satisfy:
In formula (9), z represents the surface vector parallel to z axis, and z axis is an optical axis of the optical system; c is the central curvature radius of the aspheric surface; k is a constant of center of quadric surface; A˜J are higher order coefficients.
In some optional embodiments, as shown in
According to the embodiment of the present application, as shown in
In one embodiment, the present embodiment provides a metalens. The metalens includes a substrate 201 and two nanostructured layers 202 setting on the substrate 201. From the direction away from the substrate 201, the two nanostructured layers 202 are first nanostructured layer and the second nanostructured layer. The specific parameter item are as shown in Table 1.
In embodiment 1, the wide-spectrum phase of any unit cell 203 and the working waveband of the metalens also satisfy:
In one embodiment, the present embodiment provides a metalens. The metalens includes a substrate 201 and two nanostructured layers 202 setting on the substrate 201. From the direction away from the substrate 201, the two nanostructured layers 202 are the first nanostructured layer and the second nanostructured layer. The specific parameter item are shown in Table 2.
In embodiment 1, the wide-spectrum phase of any unit cell 203 and the working waveband of the metalens also satisfy:
In the second aspect, the manufacturing method for the metalens is provided, and the manufacturing method is applied to the second metalens 20 in any embodiment provided by the present application. As shown in
Optionally, as shown in
In one embodiment, embodiment 3 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 4 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 5 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 6 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 7 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 8 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 9 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 10 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 11 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 12 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 13 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 14 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 15 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 16 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 17 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 18 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 19 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 20 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 21 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 22 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 23 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 24 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 25 provides an optical system, and the optical system is shown in
In one embodiment, embodiment 26 provides an optical system, and the optical system is shown in
It should be noted that the metalens provided by the embodiment of the present application can be processed through a semiconductor process and has the advantages of light weight, thin thickness, simple structure and process, low cost and high consistency in mass production.
In conclusion, the optical system provided by the embodiment of the present application forms the seven-piece optical system by using at least one metalens and a plurality of aspheric refractive lenses, which satisfying that the F number is less than 2 and the total length of the system is less than 6 mm, and improves the miniaturization and lightweight of the optical system.
The above is only a specific embodiment of the embodiments of this disclosure, but the scope of protection of the embodiment of this disclosure is not limited to this. And those skilled in the field can easily think of any change or substitution for this disclosure, which should be covered within the protection scope of this disclosure. Therefore, the scope of the protection of the present disclosure shall be the scope of the claims.
Number | Date | Country | Kind |
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202210726532.8 | Jun 2022 | CN | national |
202221596000.9 | Jun 2022 | CN | national |
This application is a continuation of International Patent Application of PCT application serial No. PCT/CN2023/097326, filed on May 31, 2023, which claims the benefit of priority from China Application No. 202210726532.8 and No. 202221596000.9, both filed on Jun. 24, 2022. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.
Number | Date | Country | |
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Parent | PCT/CN2023/097326 | May 2023 | WO |
Child | 18991076 | US |