Under-screen optical system and under-screen optical module

Abstract

The utility model provides an under-screen optical system. The under-screen optical system is arranged between a pixelated display screen and an optical sensor. The under-screen optical system comprises at least one super lens and at least one refraction lens. The super lens comprises a substrate and at least one structural surface formed on at least one surface of the substrate; each structural surface comprises a layer of micro-nano structure, the micro-nano structure is a negative micro-nano structure or a positive micro-nano structure, and the depth-to-width ratio of the micro-nano structure is smaller than or equal to 40. According to the under-screen optical system provided by the invention, the adverse effect of high-order light generated by the screen on imaging can be reduced, and the micro-nano structure can be prevented from having too high processing difficulty while the high imaging quality is met, so that the under-screen optical system has a relatively high processing yield.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical systems, and more specifically, to an under-screen optical system and an under-screen optical module. Background Art

[0002] In various electronic devices, due to the needs of front-facing cameras, fingerprint recognition, or facial recognition, it is often necessary to set an optical system for imaging on one side of the electronic device close to the display screen. The most common practice is to open a window on the display screen, and then set up an optical system in the window area to ensure that the optical system can form a clear and stable image. However, this approach will cause the display screen to appear as an unsightly special-shaped screen (for example: a notch screen), and it will also reduce the effective display area of ​​the display screen.

[0003] In order to avoid opening a window on the display screen when setting up an optical system for imaging, the related art proposes a design scheme of an under-screen optical system, that is, setting the optical system under the display screen. However, the under-screen optical system provided by the related art is difficult to have high imaging quality while ensuring a small system size. Utility Model Content

[0004] In order to solve the above technical problems, the present application provides an under-screen optical system and an under-screen optical module, which can have high imaging quality while ensuring a small system size while meeting high imaging quality.

[0005] A first aspect of an embodiment of the present application provides an under-screen optical system, which is arranged between a pixelated display screen and an optical sensor, and includes at least one superlens and at least one refractive lens; the superlens includes a substrate and at least one structural surface formed on at least one surface of the substrate; each structural surface includes a layer of micro-nano structure, the micro-nano structure is a negative micro-nano structure or a positive micro-nano structure, and the aspect ratio of the micro-nano structure is less than or equal to 40.

[0006] Optionally, among the at least two structure surfaces formed on the same surface of the substrate, the micro-nano structure included in at least one structure surface is a negative micro-nano structure, and the micro-nano structure included in at least one structure surface is a positive micro-nano structure.

[0007] Optionally, the operating band of the under-screen optical system is a visible light or near-infrared wide-spectrum band.

[0008] Optionally, the under-screen optical system includes at least one spherical lens.

[0009] Optionally, the under-screen optical system includes at least one aspherical lens.

[0010] Optionally, the under-screen optical system is provided with a first refractive lens, a second refractive lens and a first super lens in sequence along the optical axis from the object side to the image side.

[0011] Optionally, the first refractive lens and the second refractive lens are both spherical lenses; the object side of the first refractive lens is convex toward the object side, the image side of the first refractive lens is convex toward the image side, and the curvature of the object side of the first refractive lens is greater than the curvature of the image side of the first refractive lens; the object side of the second refractive lens is convex toward the object side, the image side of the second refractive lens is convex toward the image side, and the curvature of the object side of the second refractive lens is less than the curvature of the image side of the second refractive lens.

[0012] Optionally, the first metalens comprises only one structured surface.

[0013] Another aspect of an embodiment of the present application provides an under-screen optical module, including a display screen, an optical sensor, and an under-screen optical system as described in any one of the above items.

[0014] Optionally, the display screen is a liquid crystal screen or an organic light emitting diode (OLED) screen.

[0015] According to the optical system provided by the embodiment of the present application, the optical system is arranged between the display screen and the optical sensor, and the optical system includes at least one metalens and at least one refractive lens; the metalens includes a substrate and at least one structural surface formed on at least one surface of the substrate; each structural surface includes a layer of micro-nano structure, the micro-nano structure is a negative micro-nano structure or a positive micro-nano structure, and the aspect ratio of the micro-nano structure is less than or equal to 40. The arrangement of at least one metalens and at least one refractive lens is conducive to reducing the adverse effects of the diffraction effect of the high-order light generated by the display screen on the imaging of the optical system under the screen, thereby ensuring that the optical system under the screen has a high imaging clarity, so that it can have a high imaging quality while ensuring a small system size. In addition, the aspect ratio of the micro-nano structure is less than or equal to 40, which can avoid the excessive difficulty of processing the micro-nano structure, thereby meeting the technical requirements of the optical system under the screen having a high processing yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology are described below. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram showing the architecture layout of an under-screen optical system and an under-screen optical module in one embodiment of the present application is shown;

[0018] Figure 2A schematic diagram of the structure of a super lens in an under-screen optical system in one embodiment of the present application is shown;

[0019] Figure 3 A method for designing structural parameters of an under-screen optical system in one embodiment of the present application is shown;

[0020] Figure 4 A method for optimizing the structural parameters of the under-screen optical system in one embodiment of the present application is shown;

[0021] Figure 5 A schematic diagram of the architecture layout of the under-screen optical system in one embodiment of the present application is shown;

[0022] Figure 6 The surface phase curve of the metalens in one embodiment of the present application is shown;

[0023] Figure 7 The figure shows a point diagram of the imaging of the under-screen optical system in one embodiment of the present application;

[0024] Figure 8 The point spread function of the imaging of the under-screen optical system in one embodiment of the present application is shown;

[0025] Fig. 9 A schematic diagram showing the architecture layout of the under-screen optical system in the comparative example provided in the present application is shown;

[0026] Fig.10 The point diagram of the imaging of the under-screen optical system in the comparative example provided in the present application is shown;

[0027] Fig.11 The point spread function of the imaging of the under-screen optical system in the comparative example provided in the present application is shown;

[0028] Fig.12 The imaging effect of the under-screen optical module corresponding to the under-screen optical system in the comparative example provided in the present application is shown;

[0029] Fig.13 The imaging effect of the under-screen optical module corresponding to the under-screen optical system in one embodiment of the present application is shown.

[0030] List of reference numerals:

[0031] 10-display screen, 200-substrate, 201-negative micro-nano structure, 202-positive micro-nano structure, 21-first refractive lens, 22-second refractive lens, 23-first super lens, 30-optical sensor, 41-first aspheric lens, 42-second aspheric lens. DETAILED DESCRIPTION

[0032] The present application will now be described more fully below with reference to the accompanying drawings, in which various embodiments are shown. However, the present application can be implemented in many different ways and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application will be exhaustive and complete, and will fully convey the scope of the present application to those skilled in the art. The same reference numerals throughout the text represent the same components. Furthermore, in the accompanying drawings, the thickness, ratios, and sizes of the components are exaggerated for clarity.

[0033] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, "one", "the", "at least one" as used herein do not represent a limitation on quantity, but are intended to include both the singular and the plural. For example, unless the context clearly indicates otherwise, "a component" has the same meaning as "at least one component". "At least one" should not be interpreted as being limited to the number "one". "Or" means "and / or". The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meanings as in the relevant technical context, and unless clearly defined in the specification, these terms are not interpreted as having formal meanings in an idealized or overly formal sense.

[0035] The meaning of “include” or “comprising” specifies properties, quantities, steps, operations, components, parts or a combination thereof, but does not exclude other properties, quantities, steps, operations, components, parts or a combination thereof.

[0036] Embodiments are described herein with reference to cross-sectional views as idealized embodiments. Thus, variations in shape relative to the illustrated diagram are anticipated as a result of, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be interpreted as being limited to the specific shapes of the regions as shown herein, but should include deviations in shape due to, for example, manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. Moreover, the sharp angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of the regions and are not intended to limit the scope of the claims.

[0037] It should be noted that a pixelated display screen refers to a display screen that includes pixel units for emitting light to display images. For a pixelated display screen, the smaller the size of the pixel unit, the greater the light energy and deflection angle of the high-order light generated by the display screen. Moreover, due to the consideration of thin and light design, the space under the display screen for setting up the under-screen optical system is very limited, so the under-screen optical system needs to be compactly designed to avoid the system being too large so as to be as close to the display screen as possible. The closer the under-screen optical system is to the display screen, the easier it is to receive the high-order light generated by the display screen. The reception of high-order light will cause the point spread function of the under-screen optical system to have side lobes, which will lead to blurred imaging of the under-screen optical module, making it difficult to have high imaging quality while ensuring a small system size.

[0038] In order to overcome the above-mentioned defects, the present application proposes an under-screen optical system and an under-screen optical module comprising the same.

[0039] Figure 1 A schematic diagram of the architecture layout of an under-screen optical system provided by an embodiment of the present application is shown. The under-screen optical system is arranged between a pixelated display screen and an optical sensor; the under-screen optical system includes at least one metalens and at least one refractive lens.

[0040] like Figure 2 As shown, the superlens includes a substrate 200 and at least one structural surface formed on at least one surface of the substrate 200, each structural surface includes a layer of micro-nano structure, the micro-nano structure is a negative micro-nano structure 201 or a positive micro-nano structure 202, and the aspect ratio of the micro-nano structure is less than or equal to 40.

[0041] It should be noted that the metalens mainly plays the role of phase modulation of the incident light and correction of the dispersion of the wide spectrum. The arrangement of at least one metalens and at least one refractive lens is conducive to reducing the adverse effect of the diffraction effect of the high-order light generated by the display screen on the imaging of the optical system under the screen, thereby improving the imaging clarity of the optical system under the screen. At the same time, the aspect ratio of the micro-nano structure is less than or equal to 40, which can avoid excessive processing difficulty of the micro-nano structure, so that the metalens and the optical system have a higher processing yield.

[0042] Specifically, the structural surface includes micro-nano structures and filling materials between the micro-nano structures, and the filling materials between the micro-nano structures are air or other materials that are transparent in the working band. The various parameters of the micro-nano structures can be adaptively configured using a matching phase modulation formula, so that the superlens can achieve corresponding optical performance.

[0043] In an optional embodiment, the structured surface is formed only on the object side of the substrate 200 .

[0044] In an optional embodiment, the structured surface is formed only on the image-side surface of the substrate 200 .

[0045] In an optional embodiment, the structured surface is formed on both the object-side surface and the image-side surface of the substrate 200 .

[0046] In an optional embodiment, two or more layers of structural surfaces are formed on a certain surface of the substrate 200, or two or more layers of structural surfaces are formed on both sides of the surface. On the same surface, the micro-nano structure contained in at least one structural surface is a negative micro-nano structure 201, and the micro-nano structure contained in at least one structural surface is a positive micro-nano structure 202. It should be noted that the relationship between the dispersion and wavelength of the positive micro-nano structure 202 is opposite to the relationship between the dispersion and wavelength of the negative micro-nano structure 201. Therefore, by simultaneously including at least two layers of positive and negative opposite micro-nano structures, the degree of dispersion superposition between the micro-nano structures can be reduced, which is beneficial to reducing the dispersion of the optical system under the screen and making the superlens have a larger and expected optical focal length.

[0047] In an optional embodiment, the operating band of the under-screen optical system is a visible light or near-infrared wide-spectrum band.

[0048] In an optional embodiment, the operating band of the under-screen optical system is 430-670nm.

[0049] In an optional embodiment, the under-screen optical system includes at least one spherical lens.

[0050] In an optional embodiment, the under-screen optical system includes at least one aspherical lens, which is mainly used to correct aberrations, thereby facilitating obtaining higher imaging quality.

[0051] like Figure 3 As shown, in the embodiment of the present application and various optional embodiments, the structural parameters of the under-screen optical system can be obtained by a design method comprising at least the following steps:

[0052] Determine the initial constraints and initial structural parameters of the under-screen optical system according to design requirements;

[0053] Based on the physical field propagation calculation and initial constraint conditions, the initial structural parameters are optimized to obtain the imaging structural parameters;

[0054] Based on physical field ray tracing of the imaging structure parameters, the imaging structure parameters are optimized at least once until the target structure parameters are obtained.

[0055] Specifically, according to the design requirements, the initial constraints and initial structural parameters of the under-screen optical system are determined, wherein the initial structural parameters are limited by the initial constraints. In the embodiment of the present application and various optional embodiments, the initial constraints may be, for example, cost, operating band, ambient temperature, field of view, focal length, transmittance, modulation transfer function, and total length of the optical system, and the initial structural parameters may be, for example, the material, quantity, thickness, distance between lens groups, phase of the metalens, and curvature of the refractive lens and the metalens; when the refractive lens includes an aspheric lens, the initial structural parameters also include the aspheric coefficient of the aspheric lens.

[0056] More specifically, for example: when the total length of the under-screen optical system is used as a constraint, it is necessary to optionally limit, for example, the number and thickness of refractive lenses and super lenses, as well as the curvature of the refractive lenses in the initial structural parameters; when the cost of the under-screen optical system is used as a constraint, the materials of the refractive lenses and super lenses and the number of aspheric lenses in the initial structural parameters are optionally limited; when the ambient temperature of the under-screen optical system is used as a constraint, the refractive index temperature coefficient of the material of the refractive lens needs to be limited in the initial structural parameters.

[0057] The process of optimizing the initial structural parameters and obtaining the imaging structural parameters further includes using physical field propagation to calculate the point spread function of the optical system, analyzing the MTF curve based on the point spread function, and optimizing the initial structural parameters as variables to the imaging structural parameters that meet the design requirements of the optical system.

[0058] Furthermore, if Figure 4 As shown, the process of optimizing the imaging structure parameters to obtain the target structure parameters includes at least the following steps:

[0059] Based on the field propagation algorithm calculation, the optical performance of the under-screen optical system is obtained;

[0060] Determine whether the optical performance meets the optimization evaluation indicators:

[0061] If yes, the target structure parameters are obtained;

[0062] If not, the optimization direction of the imaging structure parameters is determined based on the optical performance, and the imaging structure parameters are optimized until they meet the optimization evaluation index.

[0063] Specifically, firstly, based on the current imaging structure parameters, the optical performance of the current imaging structure parameters is obtained through a physical field ray tracing algorithm; in the embodiment of the present application and various optional embodiments, the optical performance may be, for example, a point spread function and an optical point diagram.

[0064] Then determine whether the optical performance meets the optimization evaluation index; in the embodiment of the present application and various optional embodiments, the optimization evaluation index may be, for example, high-order diffraction and relative irradiance of the under-screen optical system.

[0065] If the optical performance does not meet the optimization evaluation index, the optimization direction of the optical performance of the current imaging structure parameters is determined according to the optimization algorithm; in the embodiment of the present application and various optional embodiments, the optimization algorithm can be a gradient descent algorithm, a random algorithm such as a simulated annealing algorithm and a particle swarm algorithm, or a reinforcement learning algorithm such as a deep learning algorithm; the change direction of the current imaging structure parameters is guided by the optimization direction, a new set of imaging structure parameters is obtained, and the optical performance is recalculated until the optical system performance meets the optimization evaluation index, and the imaging structure parameters at this time are used as the target structure parameters.

[0066] Furthermore, based on the obtained target structural parameters, the layout of the metalens, the processing drawing of the refractive lens, and the assembly drawing of the under-screen optical system are determined, and production and debugging are carried out.

[0067] In an optional embodiment, if Figure 5 As shown, the under-screen optical system is provided with a first refractive lens 21, a second refractive lens 22 and a first super lens 23 in sequence along the optical axis from the object side to the image side.

[0068] In an optional embodiment, the first refractive lens 21 and the second refractive lens 22 are both spherical lenses; the object side of the first refractive lens 21 is convex toward the object side, the image side of the first refractive lens 21 is convex toward the image side, and the curvature of the object side of the first refractive lens 21 is greater than the curvature of the image side of the first refractive lens 21; the object side of the second refractive lens 22 is convex toward the object side, the image side of the second refractive lens 22 is convex toward the image side, and the curvature of the object side of the second refractive lens 22 is less than the curvature of the image side of the second refractive lens 22. Specifically, the first refractive lens 21 and the second refractive lens 22 are both biconvex spherical lenses, which can play a good role in focusing light beams.

[0069] In an optional embodiment, Figure 5 In the under-screen optical system shown, the first superlens 23 includes only one structural surface, which can reduce the processing difficulty and improve the production yield of the optical system.

[0070] This application also provides an under-screen optical module, see Figure 1 The under-screen optical module includes a display screen 10, an optical sensor 30, and an under-screen optical system provided by any of the above embodiments. The detailed design of the under-screen optical system will not be described here.

[0071] In an optional embodiment, the display screen 10 is a liquid crystal screen.

[0072] In an optional embodiment, the display screen 10 is an organic light emitting diode (OLED) screen.

[0073] To further describe the features of the optical system provided in the embodiments of the present application, the present application provides comparative examples and embodiments obtained according to the above design method as follows:

[0074] Example

[0075] Figure 5 FIG. 1 shows a schematic diagram of the layout of an optical system under the screen provided in this embodiment. Figure 5 In this embodiment, the under-screen optical system includes a first refractive lens 21, a second refractive lens 22, and a super lens 23, which are sequentially arranged along the optical axis from the object side to the image side. The first refractive lens 21 and the second refractive lens 22 are both spherical lenses, and the aperture is arranged on the object side of the first refractive lens 21.

[0076] The surfaces in the optical system provided in the embodiment are numbered from the object side to the image side, and parameters such as the curvature radius, thickness, and material of each lens surface in the optical system are summarized to obtain Table 1.

[0077] Table 1. Surface parameters of the optical system provided in the embodiment

[0078]

[0079]

[0080] Referring to Table 1, surface 0 is the object plane; the object plane is a spherical surface with an infinite radius of curvature, that is, object plane 0 is a plane. Surface 1 is an aperture, and the radius of curvature of surface 1 is infinite, therefore, surface 1 is a plane, and the distance between it and surface 2 is 0.1 mm. Surface 2 is the upper surface of the display screen 10, surface 2 is a plane, and the distance between it and surface 3 is 0.1 mm. The material between it and surface 3 is BK7, and BK7 is the optical glass brand of the schott manufacturer. Surface 3 is the lower surface of the display screen 10, surface 3 is a plane, and the distance between it and surface 4 is 0.1 mm. The material between it and surface 4 is air. Surface 4 is the object side surface of the first refractive lens 21, and its radius of curvature is 0.689 mm. The distance between it and surface 5 is 0.1 mm. The material between it and surface 5 is H-ZPK7, and H-ZPK7 is the optical glass brand of the Chengdu Guangming manufacturer. Surface 5 is the image side surface of the first refractive lens 21, and its radius of curvature is -3.136mm. The distance between it and surface 6 is 0.1mm, and the material between it and surface 6 is air. Surface 6 is the object side surface of the second refractive lens 220, and its radius of curvature is 2.318mm. The distance between it and surface 7 is 0.1mm. The material between it and surface 7 is H-ZPK5, and H-ZPK5 is the optical glass brand of Chengdu Guangming Manufacturer. Surface 7 is the image side surface of the second refractive lens 22, and its radius of curvature is -0.784mm. The distance between it and surface 8 is 0.1mm, and the material between it and surface 8 is air. Surface 8 is the object side surface of the super lens 23, and the radius of curvature of surface 8 is infinite, so surface 8 is a plane, and the distance between it and surface 9 is 0.1mm, and the material between it and surface 9 is silicon dioxide. Surface 9 is the image side surface of the super lens 23. The radius of curvature of surface 9 is infinite, so surface 9 is a plane. The distance between surface 9 and surface 10 is 0.221 mm, and the material between surface 9 and surface 10 is air. Surface 10 is the image plane. The radius of curvature of surface 10 is infinite, so surface 10 is a plane.

[0081] Figure 6 Graph 2 shows the surface phase curve of the superlens 23 in this embodiment, where Figure 6 The horizontal axis represents the position of the surface of the superlens 23, and its unit is millimeter. Figure 6 The vertical axis represents the phase, and its unit is 2π radians.

[0082] Figure 7 : shows the spot diagram of the imaging of the under-screen optical system in this embodiment, Figure 7 It reflects the diffuse pattern dispersed within a certain range formed after light of different wavelengths passes through the optical system under the screen.

[0083] Figure 8 The point spread function of the imaging of the under-screen optical system in this embodiment is shown in FIG. Figure 8The horizontal axis represents the position on the image plane of the optical system under the screen, and its unit is millimeter. Figure 8 The vertical axis represents relative irradiance.

[0084] Comparative Example

[0085] Fig. 9 A schematic diagram of the layout of an optical system under the screen provided in the comparative example is shown. Fig. 9 In the comparative example, the under-screen optical system includes a first aspheric lens 41 and a second aspheric lens 42 which are sequentially arranged along the optical axis from the object side to the image side, and the aperture is arranged on the object side of the first aspheric lens 41. The first aspheric lens 41 and the second aspheric lens 42 are both even-order aspheric lenses, the object side surface and the image side surface of the first aspheric lens 41 are both convex toward the image side, and the curvature of the object side surface of the first aspheric lens 41 is smaller than the curvature of the image side surface of the first aspheric lens 41, the object side surface of the second aspheric lens 42 is convex toward the object side, the image side surface of the second aspheric lens 42 is convex toward the image side, and the curvature of the object side surface of the second aspheric lens 42 is smaller than the curvature of the image side surface of the second aspheric lens 42.

[0086] According to the direction from the object side to the image side, each surface in the under-screen optical system provided by the comparative example is numbered, and the parameters such as the curvature radius, thickness and material of each lens surface in the under-screen optical system are summarized to obtain Table 2.

[0087] Table 2. Surface parameters of the under-screen optical system provided by the comparative example

[0088] Surface serial number Surface type Curvature radius (mm) Thickness(mm) Material 0 Physical surface unlimited unlimited - 1 Aperture unlimited 0.000 2 Spherical unlimited 0.100 BK7 3 Spherical unlimited 0.100 - 4 even aspherical surface -3.885 0.100 H-ZPK7 5 even aspherical surface -0.594 0.100 - 6 even aspherical surface 1.280 0.100 H-ZPK5 7 even aspherical surface -0.743 0.421 - 8 Image plane unlimited - -

[0089] Referring to Table 2, surface 0 is the object plane; the object plane is a spherical surface with an infinite radius of curvature, that is, object plane 0 is a plane. Surface 1 is an aperture, surface 1 is a plane, and surface 1 is arranged on surface 2. Surface 2 is the upper surface of the display screen 10, surface 2 is a plane, and the distance between it and surface 3 is 0.1 mm, and the material between it and surface 3 is BK7. Surface 3 is the lower surface of the display screen 10, surface 3 is a plane, and the distance between it and surface 4 is 0.1 mm, and the material between it and surface 4 is air. Surface 4 is the object side surface of the first aspheric lens 41, and the radius of curvature thereof is -3.885 mm, and the distance between it and surface 5 is 0.1 mm, and the material between it and surface 5 is H-ZPK7. Surface 5 is the image side surface of the first aspheric lens 41, and the radius of curvature thereof is -0.594 mm, and the distance between it and surface 6 is 0.1 mm, and the material between it and surface 6 is air. Surface 6 is the object side surface of the second aspheric lens 42, and its curvature radius is 1.28 mm. The distance between it and surface 7 is 0.1 mm, and the material between it and surface 7 is H-ZPK5. Surface 7 is the image side surface of the second aspheric lens 42, and its curvature radius is -0.743 mm. The distance between it and surface 8 is 0.421 mm, and the material between it and surface 8 is air. Surface 8 is the image surface, and the curvature radius of surface 8 is infinite, so surface 8 is a plane.

[0090] Fig.10 The point diagram of the imaging of the under-screen optical system in the comparative example is shown. Fig.10 It reflects the diffuse pattern dispersed within a certain range formed after light of different wavelengths passes through the optical system under the screen.

[0091] Fig.11 The point spread function of the imaging of the under-screen optical system in the comparative example is shown. Fig.11 The horizontal axis represents the position on the image plane of the optical system under the screen, and its unit is millimeter. Fig.11 The vertical axis represents the relative irradiance.

[0092] Comparing the above-mentioned embodiment with the comparative example, it can be seen that the thickness of the under-screen optical system provided by the embodiment of the present application is not greater than that of the under-screen optical system provided by the comparative example. At the same time, the root mean square radius of the optical point diagram of the under-screen optical system provided by the embodiment of the present application is much smaller than that of the under-screen optical system provided by the comparative example, that is, it has a better focusing effect and a higher relative radiation illumination intensity.

[0093] Fig.12 The figure shows the imaging effect of the under-screen optical module corresponding to the under-screen optical system provided in the comparative example after being received by the system. Fig.13 The imaging effect of the under-screen optical module corresponding to the under-screen optical system provided in the embodiment after being received by the optical system is shown. Fig.12 and Fig.13By comparison, it can be seen that the imaging clarity of the under-screen optical system provided by the embodiment of the present application is better than that of the under-screen optical system using only aspherical lenses. In summary, the optical system provided by the embodiment of the present application is conducive to eliminating the side lobes of the point spread function of the optical system, thereby reducing the influence of the diffraction effect of the screen on the imaging clarity of the optical system.

[0094] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the embodiment of the present application, which should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application shall be based on the protection scope of the claims.

Claims

1. An under-screen optical system, characterized in that: The under-screen optical system is arranged between a pixelated display screen (10) and an optical sensor (30); the under-screen optical system comprises at least one metalens and at least one refractive lens; The superlens comprises a substrate (200) and at least one structural surface formed on at least one surface of the substrate (200); each of the structural surfaces comprises a layer of micro-nano structure, and the micro-nano structure is a negative micro-nano structure (201) or a positive micro-nano structure (202); and the aspect ratio of the micro-nano structure is less than or equal to 40.

2. The under-screen optical system according to claim 1, characterized in that: Among the at least two structural surfaces formed on the same surface of the substrate (200), the micro-nano structure included in at least one structural surface is a negative micro-nano structure (201), and the micro-nano structure included in at least one structural surface is a positive micro-nano structure (202).

3. The under-screen optical system according to claim 1, characterized in that: The working band of the under-screen optical system is a visible light or near-infrared wide-spectrum band.

4. The under-screen optical system according to claim 1, characterized in that: The under-screen optical system includes at least one spherical lens.

5. The under-screen optical system according to claim 1, characterized in that: The under-screen optical system includes at least one aspherical lens.

6. The under-screen optical system according to claim 1, characterized in that: The under-screen optical system is provided with a first refractive lens (21), a second refractive lens (22) and a first super lens (23) in sequence from the object side to the image side along the optical axis.

7. The under-screen optical system according to claim 6, characterized in that: The first refractive lens (21) and the second refractive lens (22) are both spherical lenses; The object side of the first refractive lens (21) is convex toward the object side, the image side of the first refractive lens (21) is convex toward the image side, and the curvature of the object side of the first refractive lens (21) is greater than the curvature of the image side of the first refractive lens (21); The object side of the second refractive lens (22) is convex toward the object side, the image side of the second refractive lens (22) is convex toward the image side, and the curvature of the object side of the second refractive lens (22) is smaller than the curvature of the image side of the second refractive lens (22).

8. The under-screen optical system according to claim 7, characterized in that: The first superlens (23) comprises only one structural surface.

9. An under-screen optical module, characterized in that: It comprises a display screen (10), an optical sensor (30), and an under-screen optical system according to any one of claims 1 to 8.

10. The under-screen optical module according to claim 9, characterized in that: The display screen (10) is a liquid crystal screen or an organic light emitting diode (OLED) screen.

Images