Lens based on metasurface and intelligent device

Abstract

The utility model relates to a metasurface-based lens and intelligent equipment, and belongs to the field of optical elements, the lens sequentially comprises a super lens group and a reflecting layer from top to bottom, the super lens group is composed of at least two super lenses, any super lens is composed of a substrate and a nanostructure arranged above the substrate, the number of layers of the nanostructure is 1-3, and the number of the layers of the nanostructure is 1-3. The transverse size of the nanostructure is adjustable in the range of 100 nm to 500 nm. The total length and the weight of the camera lens are reduced in a mode that the lenses are arranged side by side.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical elements, and particularly relates to a lens based on a metasurface. BACKGROUND

[0002] As a necessary electronic product, a smart phone has been integrated into all aspects of life, such as communication, entertainment, photography and the like. With the pixel size of a CMOS chip becoming smaller and smaller, the resolution of a smart phone is also continuously improved.

[0003] However, it is a great challenge for a camera lens to achieve a higher MTF while taking into account the characteristics of small size and short total length. At present, a periscopic lens is often used to bend the light path, thereby reducing the total length of the system, but the introduction of a prism and the like will inevitably increase the weight. CONTENT OF THE INVENTION

[0004] The present application provides a lens based on a metasurface and a smart device to at least solve the above technical problems in the prior art.

[0005] The present application provides a lens based on a metasurface, which comprises, from top to bottom, a metasurface lens group and a reflection layer, the metasurface lens group is composed of at least two metasurface lenses, any metasurface lens is composed of a substrate and a nanostructure arranged above the substrate, the nanostructure has 1-3 layers, and the lateral size of the nanostructure is adjustable within the range of 100 nm-500 nm.

[0006] In an implementable manner, the diameter of the metasurface lens is independently adjustable, and the adjustment range is 1-50 mm.

[0007] In an implementable manner, the metasurface lens group is composed of a first metasurface lens and a second metasurface lens, and the axial spacing between the first metasurface lens and the second metasurface lens is adjustable, and the adjustment range is 0.5-5 mm.

[0008] In an implementable manner, the reflection band of the reflection layer can cover

[0009] a specified wavelength interval within the range of 320 nm-1550 nm.

[0010] In an implementable manner, the lens further comprises a diaphragm, and the diaphragm is arranged at the front end of the lens.

[0011] In an implementable manner, the lens further comprises an imaging sensor.

[0012] In an implementable manner, the phase of the metasurface lens is represented as:

[0013]

[0014] or represented as:

[0015]

[0016] wherein, φ(x,y) represents the phase response value at different positions on the superlens at a specific wavelength, λ represents the wavelength, f represents the focal length, Δy represents the oblique focusing offset; x, y represent the positions in two orthogonal directions.

[0017] In another aspect, the embodiment of the present application provides a kind of intelligent device, including any lens described above.

[0018] In an implementation, the intelligent device is a mobile phone or a camera. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the schematic diagram of the lens in the embodiment of the present application;

[0020] Figure 2 is the phase surface distribution schematic diagram of the first superlens in the embodiment of the present application;

[0021] Figure 3 is the phase surface distribution schematic diagram of the second superlens in the embodiment of the present application;

[0022] Figure 4 is the schematic diagram of the plane lens combined with the superlens and the refractive lens in the embodiment of the present application;

[0023] Figure 5 is the top view phase distribution schematic diagram of the superlens plane lens in the embodiment of the present application. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below with reference to the accompanying drawings.

[0025] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0026] The present application discloses a kind of lenses based on super surface, referring to Figure 1 which includes superlens group and reflection layer 14 from top to bottom in sequence, superlens group is composed of at least two superlenses, any superlens is composed of base 16 and nanostructure arranged above the base, the layer number of nanostructure is 1-3 layers, the lateral dimension of nanostructure is adjustable in the range of 100nm-500nm.

[0027] The material of the substrate 16 can be glass, which acts as the carrier of the entire lens group. The nanostructure of the superlens is attached to the upper surface thereof.

[0028] The diameter of the superlens is independently adjustable, and the adjustment range is 1-50 mm. The superlens group is composed of a first superlens 12 and a second superlens 13, and the axial distance between the first superlens 12 and the second superlens 13 is adjustable, and the adjustment range is 0.5-5 mm.

[0029] The phase of the superlens is represented as:

[0030]

[0031] or represented as:

[0032]

[0033] wherein φ(x, y) represents the phase response value at a specific wavelength at different positions on the superlens, λ represents the wavelength, f represents the focal length, and Δy represents the tilt focusing offset; x and y represent the positions in two orthogonal directions.

[0034] The reflective layer 14 can be a high-reflection film, which is coated on the lower surface of the substrate 16. The reflective layer 14 serves to increase the reflection efficiency of light and reduce energy loss. According to the type of film coating according to the working wavelength of the lens, the wavelength range covered is between 320 nm and 1550 nm.

[0035] In addition to the above three components, the lens also includes a diaphragm 11, which serves to cooperate with the parameters of the lens group to achieve better imaging effect, and the diaphragm 11 is arranged at the front end of the lens.

[0036] The lens also includes an imaging sensor 15, which can be packaged together with the entire lens group and the sensor by using a semiconductor process, thereby greatly reducing the volume of the system.

[0037] Embodiment 1

[0038] As shown in Figure 1 is a typical two-piece superlens system. The lens includes a diaphragm 11, a first superlens 12, a second superlens 13, a reflective layer 14, an imaging sensor 15, and a substrate 16, wherein the nano pillar height of the two superlenses is 700 nm, the period is 450 nm, the selected material is single crystal silicon, and the working wavelength is 940 nm. The distance between the first superlens 12 and the second superlens 13 is 5 mm, the glass material of the substrate 16 is SiO2, and the thickness is 0.5 mm. The reflective layer 14 is selected to be a high-reflection film, and the high reflectivity at the 940 nm wavelength band is >99.9%

[0039] The phase distribution of the superlens is as shown in Figure 2 and Figure 3As shown in Figure 2 As shown in Figure 3 It can be seen from the phase planes that the eccentric arrangement is used to ensure the normal imaging function of the system.

[0040] Comparative Example 1

[0041] The difference between the present comparative example and Example 1 is that the second superlens is replaced by a conventional refractive lens, so as to prove that the lens of the present application can reduce the total length of the lens without reducing the reflection efficiency.

[0042] As shown in Figure 4 As shown in Figure 5 A typical planar lens combining a superlens and a refractive lens is shown. The lens comprises a diaphragm 11, a first superlens 12, a refractive lens 13, a reflective layer 14, an imaging sensor 15 and a substrate 16. The nanocolumns of the first superlens 13 have a height of 700 nm, a period of 450 nm and are made of monocrystalline silicon, and the working wavelength is 940 nm. The distance between the first superlens 12 and the refractive lens 13 is 5 mm. The glass material of the substrate 16 is SiO2, and the thickness is 0.5 mm. The reflective layer 14 is an antireflection film, and the high reflectivity at the wavelength of 940 nm is >99.9%.

[0043] The present application also discloses a smart device comprising any of the lenses.

[0044] The smart device can be an electronic device such as a mobile phone or a camera.

[0045] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present disclosure, which should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A lens based on a metasurface, characterized in that, The structure consists of a superlens group and a reflective layer from top to bottom. The superlens group is composed of at least two superlenses. Each superlens consists of a substrate and a nanostructure disposed on the substrate. The number of nanostructure layers is 1-3, and the lateral dimension of the nanostructure is adjustable in the range of 100nm-500nm.

2. The lens according to claim 1, characterized in that: The diameter of the superlens is independently adjustable, with an adjustment range of 1-50mm.

3. The lens according to claim 1 or 2, characterized in that: The superlens group consists of a first superlens and a second superlens. The axial distance between the first superlens and the second superlens is adjustable, with an adjustment range of 0.5-5mm.

4. The lens according to claim 1, characterized in that: The reflection band of the reflective layer can cover a specified wavelength range of 320nm-1550nm.

5. The lens according to claim 1, characterized in that: It also includes an aperture stop, which is located at the front of the lens.

6. The lens according to claim 5, characterized in that: It also includes imaging sensors.

7. The lens according to claim 1, characterized in that, The phase of the superlens is represented as follows: Or it can be expressed as: Where φ(x,y) represents the phase response value of different positions on the superlens at a specific wavelength, λ represents the wavelength, f represents the focal length, Δy represents the oblique focusing offset, and x and y represent the positions in two orthogonal directions.

8. A smart device, characterized in that: Includes any one of the lenses in claims 1-7.

9. The intelligent device according to claim 8, characterized in that: The smart device is a mobile phone or a camera.

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