Focusing method of liquid lens

Abstract

The invention discloses a focusing method of a liquid lens, and relates to the technical field of optics. The method comprises the following steps: constructing a mathematical model according to a zoom architecture of a liquid lens; theoretical focal power is input into a mathematical model, a theoretical stroke of the liquid lens is output, and the liquid lens is controlled to perform first round focusing according to the theoretical stroke; and if there is a difference between the theoretical focal power and the actual focal power of the first round of focusing, outputting the compensation stroke of the liquid lens by inputting the theoretical focal power into the stroke correction curve, and performing the second round of focusing according to the compensation stroke. Therefore, errors generated by movement of the liquid lens are corrected by introducing the compensation stroke, and the liquid lens can accurately reach theoretical focal power, so that the stability and the accuracy of focusing are improved. Moreover, by applying the focusing method disclosed by the invention, the liquid lens can keep stable focusing performance in a complicated and changeable application scene or long-time continuous working, and the actual demand of a user is met.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a focusing method of a liquid lens. Background Art

[0002] Liquid lens technology is an emerging optical element technology that uses the physical properties of liquids (such as refractive index, etc.) to achieve dynamic adjustment of focal length. Compared with traditional mechanical zoom lenses, this technology has faster response speed, smaller size and higher integration. It has broad application prospects in imaging, machine vision, ophthalmic diagnosis and other fields.

[0003] In the related technology, one of the zoom methods of liquid lenses on the market is to squeeze the liquid to flow to the liquid lens through an electromagnetic coil, thereby changing the volume of the liquid inside the lens, thereby affecting the optical focal length of the lens. The basic principle of this technology is to use electromagnetic force to drive the liquid to flow inside the lens, and change the curvature and focal length of the lens by changing the distribution of the liquid in a very short time. The advantage of this method is that since the electromagnetic drive can be completed within a few milliseconds, the liquid lens can achieve fast zooming. In addition, the liquid lens is small in size and easy to integrate into various optical systems.

[0004] However, the process of the electromagnetic coil squeezing the liquid is complicated and difficult to control accurately. If the control is inaccurate, it may cause problems such as blurred imaging and inaccurate depth of field positioning, reducing the stability and accuracy of focus. Summary of the invention

[0005] Based on the above problems, the present application provides a focusing method of a liquid lens, which can improve the stability and accuracy of a focus-adjustable lens.

[0006] The embodiment of the present application discloses a focusing method of a liquid lens, the method comprising:

[0007] According to the zoom structure of the liquid lens, a mathematical model is constructed, wherein the mathematical model represents the corresponding relationship between the focal length and the stroke of the liquid lens;

[0008] By inputting the theoretical optical focal length into the mathematical model, a theoretical stroke of the liquid lens is output, and the liquid lens is controlled to perform a first round of focusing according to the theoretical stroke;

[0009] If there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, the theoretical optical power is input into a stroke correction curve to output a compensation stroke of the liquid lens, and a second round of focusing is performed according to the compensation stroke.

[0010] Optionally, the formula for outputting the theoretical stroke of the liquid lens by inputting the theoretical optical power into the mathematical model is specifically as follows:

[0011]

[0012] Wherein, Δl is the theoretical stroke, A and B are constants, D' is the actual optical focal length of the liquid lens, h' is the current vector height of the liquid lens, D is the theoretical optical focal length of the liquid lens, h is the target vector height of the liquid lens, R is the optical effective diameter of the liquid lens, and Δh is the vector height difference of the liquid lens.

[0013] Optionally, the step of inputting the theoretical optical power into the mathematical model to output the theoretical stroke of the liquid lens comprises:

[0014] By inputting the actual optical power and the theoretical optical power into the mathematical model, the actual liquid flow rate and the theoretical liquid flow rate in the liquid tank of the liquid lens are determined respectively;

[0015] The theoretical stroke of the liquid lens is output according to the actual liquid flow rate and the theoretical liquid flow rate.

[0016] Optionally, the formula for outputting the theoretical stroke of the liquid lens according to the actual liquid flow rate and the theoretical liquid flow rate is specifically as follows:

[0017]

[0018] Wherein, V2 is the theoretical liquid flow rate, V1 is the actual liquid flow rate, Δl is the theoretical stroke, r1 is the radius of the liquid tank, and r2 is the radius of the movable mechanical structure that drives the movable film to move.

[0019] Optionally, the stroke correction curve is as follows:

[0020] Δl'-Δl=aD 2 -bD-0.03

[0021] Wherein, Δl'-Δl is the compensation stroke, D is the theoretical optical power of the liquid lens, and a and b are multi-term coefficients.

[0022] Optionally, if there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, the compensation stroke of the liquid lens is output by inputting the theoretical optical power into a stroke correction curve, including:

[0023] If there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, fitting a stroke correction curve according to the difference between the theoretical optical power and the actual optical power of the first round of focusing, and the difference between the theoretical stroke and the actual stroke of the first round of focusing;

[0024] By inputting the theoretical optical power into a stroke correction curve, the compensation stroke of the liquid lens is output.

[0025] Optionally, controlling the liquid lens to perform a first round of focusing according to the theoretical stroke includes:

[0026] Acquiring a focus environment parameter, wherein the focus environment parameter includes at least one of a refractive index, an Abbe number, and a temperature;

[0027] According to the theoretical stroke and the focusing environment parameters, the liquid lens is controlled to perform a first round of focusing.

[0028] Optionally, the liquid lens comprises a stepping motor, a push-pull rod, a film, a liquid tank and a single-aberration adjustable focus lens imitating a human eye lens;

[0029] The liquid tank is connected to the single-aberration adjustable focus lens imitating human eye lens, the refractive index of the transparent liquid in the liquid tank is the same as the refractive index of the single-aberration adjustable focus lens imitating human eye lens, and a film is attached to the liquid tank.

[0030] Optionally, the transparent liquid flows between the liquid tank and the single-aberration adjustable focus lens imitating the human eye lens.

[0031] Optionally, when the transparent liquid flows into the single-aberration adjustable-focus lens imitating the human eye lens, it presents positive optical power, and when the transparent liquid flows out of the single-aberration adjustable-focus lens imitating the human eye lens, it presents negative optical power.

[0032] Compared with the prior art, this application has the following beneficial effects:

[0033] The present application provides a focusing method for a liquid lens, the method comprising: constructing a mathematical model according to the zoom architecture of the liquid lens; inputting the theoretical optical focal length into the mathematical model, outputting the theoretical stroke of the liquid lens, and controlling the liquid lens to perform a first round of focusing according to the theoretical stroke; if there is a difference between the theoretical optical focal length and the actual optical focal length of the first round of focusing, then inputting the theoretical optical focal length into the stroke correction curve, outputting the compensation stroke of the liquid lens, and performing a second round of focusing according to the compensation stroke. Thus, by introducing the compensation stroke to correct the error caused by the movement of the liquid lens, it is ensured that the liquid lens can accurately reach the theoretical optical focal length, thereby improving the stability and accuracy of focusing. Moreover, by applying the focusing method disclosed in the present application, whether facing complex and changeable application scenarios or long-term continuous work, the liquid lens can maintain stable focusing performance to meet the actual needs of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art 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 creative labor.

[0035] Figure 1 A schematic diagram of a focusing method of a liquid lens provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of a focusing device provided in an embodiment of the present application;

[0037] Figure 3 A flow chart for mathematical modeling of a liquid lens provided in an embodiment of the present application;

[0038] Figure 4 A flow chart of a method for obtaining a stroke correction curve provided in an embodiment of the present application;

[0039] Figure 5 A flowchart of a simplified method of a mathematical model provided in an embodiment of the present application;

[0040] Figure 6 A schematic diagram of a simplified result of a mathematical model provided in an embodiment of the present application;

[0041] Figure 7 A schematic diagram of a stroke correction curve provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] As described above, there are various ways to achieve liquid lens zoom in the current market. One typical method is to squeeze the liquid in the lens through an electromagnetic coil, causing the liquid to flow inside the lens, thereby changing the total volume of the liquid in the lens.

[0043] However, the process of electromagnetic coil squeezing liquid involves complex fluid dynamics principles, and it is difficult to accurately control the flow of liquid, which directly leads to a certain deviation between the actual change in optical power and the change in theoretical optical power. This deviation may cause problems such as reduced imaging quality and inaccurate depth of field positioning in practical applications, affecting the widespread application and further promotion of liquid lens technology.

[0044] After research, the inventor proposed a focusing method for a liquid lens, which includes: constructing a mathematical model according to the zoom architecture of the liquid lens; inputting the theoretical optical focal length into the mathematical model, outputting the theoretical stroke of the liquid lens, and controlling the liquid lens to perform the first round of focusing according to the theoretical stroke; if there is a difference between the theoretical optical focal length and the actual optical focal length of the first round of focusing, then inputting the theoretical optical focal length into the stroke correction curve, outputting the compensation stroke of the liquid lens, and performing the second round of focusing according to the compensation stroke. Thus, by introducing the compensation stroke to correct the error caused by the movement of the liquid lens, it is ensured that the liquid lens can accurately reach the theoretical optical focal length, thereby improving the stability and accuracy of the focusing. Moreover, by applying the focusing method disclosed in the present application, whether facing complex and changeable application scenarios or long-term continuous work, the liquid lens can maintain stable focusing performance and meet the actual needs of users.

[0045] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] See also Figure 1 , which is a flow chart of a focusing method of a liquid lens provided in an embodiment of the present application. The focusing method of the liquid lens is applied to a focusing device. First, the focusing device of the embodiment of the present application is explained:

[0047] See also Figure 2 , which is a schematic diagram of a focusing device provided in an embodiment of the present application. The focusing device includes: a stepping motor 201, a push-pull rod 202, a movable film 203, a liquid tank 204 and a liquid lens 205. Among them, the liquid lens 205 can be a single-aberration adjustable focusing lens that simulates the human eye lens. The radius of the liquid tank 204 is r1, the radius of the push-pull rod 202 is r2, and the effective aperture of the liquid lens 205 is R. The refractive index of the transparent liquid in the liquid tank 204 (such as water, a mixed solution of water and glycerin, a mixed solution of water and alcohol, etc.) is the same as the refractive index of the liquid lens 205.

[0048] Specifically, the stepper motor 201 rotates to drive the push-pull rod 202 to telescopically move, and the push-pull rod 202 is connected to the movable film 203 attached to the liquid tank 204, so when the push-pull rod 202 is pushed toward the liquid tank 204, the transparent liquid in the liquid tank 204 will decrease, and when the push-pull rod 202 moves away from the liquid tank 204, the transparent liquid in the liquid tank 204 will increase. Since the liquid tank 204 and the liquid lens 205 are interconnected, the transparent liquid can flow between the liquid tank 204 and the liquid lens 205. In addition, when the transparent liquid flows into the liquid lens 205, it presents a positive optical power, and when the transparent liquid flows out of the liquid lens 205, it presents a negative optical power.

[0049] Next, a focusing method of a liquid lens according to an embodiment of the present application is explained, and the method includes:

[0050] S101: constructing a mathematical model according to the zoom structure of the liquid lens, wherein the mathematical model represents the corresponding relationship between the optical power and the stroke of the liquid lens.

[0051] First, a mathematical model is constructed to characterize the correspondence between the focal length of the liquid lens 205 (i.e., the inverse of the focal length of the liquid lens 205, which measures the ability of the liquid lens 205 to converge or diverge light) and the stroke (i.e., the physical quantity that controls the shape change of the liquid lens 205, such as the distance the film moves due to the flow of liquid). Figure 3 , which is a flow chart of mathematical modeling of a liquid lens provided in an embodiment of the present application.

[0052] First, determine the relationship between the liquid flow rate V in the liquid tank 204 and the curvature radius r3 of the liquid lens 205. This is obtained through the physical principles and experimental data of the liquid lens 205, and usually involves the physical properties of the lens liquid (such as viscosity, density) and the geometric structure of the liquid lens 205.

[0053] Secondly, determine the relationship between the liquid flow rate V in the liquid tank 204 and the theoretical stroke Δl of the movable film 203. In some specific implementations, the relationship between the liquid flow rate V and the theoretical stroke Δl can be expressed as the following formula (1), which reflects how the liquid flow rate V affects the stroke of the movable film 203:

[0054]

[0055] Wherein, V is the liquid flow rate, Δl is the theoretical stroke, r1 is the radius of the liquid tank 204 , and r2 is the radius of the push-pull rod 202 .

[0056] For example, if r1=15 mm (millimeter) and r2=2.94 mm are substituted, the above formula (1) can be expressed as the following formula (2):

[0057] V 液体 =16πΔl (2)

[0058] Finally, according to the relationship between the liquid flow rate V and the radius of curvature r3, and the relationship between the liquid flow rate V and the theoretical stroke Δl, a mathematical model can be constructed to obtain the relationship between the theoretical optical power D and the theoretical stroke Δl of the liquid lens 205. In some specific implementations, the relationship between the theoretical optical power D and the theoretical stroke Δl can be shown in the following formula (3):

[0059]

[0060] Among them, Δl is the theoretical stroke, A and B are constants, D' is the actual optical focal length of the liquid lens 205, h' is the current vector height of the liquid lens 205, D is the theoretical optical focal length of the liquid lens 205, h is the target vector height of the liquid lens 205, R is the optical effective diameter of the liquid lens 205, and Δh is the vector height difference of the liquid lens 205.

[0061] For example, if A=3.42 and B=129 are substituted, the above formula (3) can be expressed as the following formula (4):

[0062]

[0063] It should be noted that the setting of A and B is related to the refractive index of the liquid lens 205 and the aperture of the liquid lens 205 , and this application does not make any limitation thereto.

[0064] In some specific implementations, the relationship between the theoretical travel Δl and the theoretical optical power D may be as shown in Table 1 below:

[0065] Table 1

[0066] NUM Theoretical optical power D Target height h Liquid flow V Theoretical stroke Δl Full power state 6.0 0.631 57.480 1.200 Normal working status 3.0 0.295 28.609 0.647 Power off state 0.5 0.055 5.513 0.109 Normal working status -3.0 -0.295 28.609 -0.647 Slow Power State -6.0 -0.631 57.480 -1.200

[0067] Among them, full power is used according to the rated maximum power of the focusing device. Using too much power will damage the focusing device; the normal working state is the most common use state of the focusing device, which provides a stable and reliable optical focal adjustment capability. The power-off state refers to the state where the optical focal length of the liquid lens is close to zero, indicating that there is no liquid flow or change. The slow power state is opposite to the full power state. At this time, the focusing device runs at a lower power and may be used in scenarios that require fine adjustment of the optical focal length. Table 1 shows the relationship between the theoretical optical focal length D, target vector height h, liquid flow rate V and theoretical stroke Δl of the liquid lens 205 under different states through specific numerical values, which helps to intuitively understand the performance of the liquid lens 205 under different working conditions.

[0068] It can be understood that when the liquid flows from the liquid tank 204 into the liquid lens 205, the radius of curvature of the liquid lens decreases (or the curvature increases) due to the increase in the amount of liquid, thereby presenting a positive optical focal length. This corresponds to the case where the theoretical optical focal length D in Table 1 is a positive value. On the contrary, when the liquid flows out of the liquid lens 205 and returns to the liquid tank 204, the radius of curvature of the liquid lens increases (or the curvature decreases), presenting a negative optical focal length. This corresponds to the case where the theoretical optical focal length D in Table 1 is a negative value.

[0069] It should be noted that in practical applications, the mathematical model obtained by the above method can be modified and optimized by combining the physical properties of the liquid lens 205 (such as the viscosity, density, refractive index, etc. of the liquid), material properties (such as the elasticity and sealing of the film, etc.) and environmental factors to achieve a more precise control effect.

[0070] S102: The theoretical optical focal length is input into a mathematical model to output a theoretical stroke of the liquid lens, and the liquid lens is controlled to perform a first round of focusing according to the theoretical stroke.

[0071] First, according to the focusing requirement or preset conditions, the required theoretical focal power D is determined. The theoretical focal power D is the optical performance parameter that the liquid lens 205 is expected to achieve. Secondly, the theoretical focal power D is input into the mathematical model constructed in step S101. Through the calculation of the mathematical model (such as formula (3)), the theoretical stroke Δl required for the liquid lens 205 to achieve the theoretical focal power D can be output. Subsequently, according to the calculated theoretical stroke Δl, the movable film 203 is controlled to move the distance of the theoretical stroke Δl, so that the liquid inside the liquid lens 205 flows, and the curvature radius of the liquid lens 205 changes, thereby achieving the required theoretical focal power D, and completing the first round of focusing.

[0072] In some other specific implementations, the actual optical focal length D' and the theoretical optical focal length D may be obtained first, and the actual optical focal length D' and the theoretical optical focal length D are respectively input into the mathematical model constructed in step S101, so as to respectively determine the actual liquid flow V1 and the theoretical liquid flow V2 in the liquid tank 204 of the liquid lens 205. Subsequently, the theoretical stroke Δl of the liquid lens is output according to the actual liquid flow V1 and the theoretical liquid flow V2. Specifically, the formula for outputting the theoretical stroke Δl of the liquid lens according to the actual liquid flow and the theoretical liquid flow is specifically shown in the following formula (5):

[0073]

[0074] Wherein, V2 is the theoretical liquid flow rate, V1 is the actual liquid flow rate, Δl is the theoretical stroke, r1 is the radius of the liquid tank, and r2 is the radius of the movable mechanical structure that drives the movable film to move.

[0075] In other specific implementations, before controlling the liquid lens to perform the first round of focusing, the focusing environment parameters, such as at least one of the refractive index, the Abbe number and the temperature, may be first obtained. Among them, the refractive index describes the change in the speed of light when it propagates in the medium. For the liquid lens 205, the refractive index of the transparent liquid inside it directly affects the optical focal length of the liquid lens 205. If the refractive index of the transparent liquid changes due to changes in the ambient temperature or pressure, the optical performance of the liquid lens 205 will also change accordingly. The Abbe number is a physical quantity that describes the dispersion ability of the liquid lens 205. Temperature is one of the key factors affecting the performance of the liquid lens. Temperature changes can cause the transparent liquid to expand or contract, thereby changing the radius of curvature and the optical focal length of the liquid lens 205. In addition, the temperature may also affect the viscosity and refractive index of the transparent liquid. Subsequently, according to the theoretical stroke Δl and the focusing environment parameters, the liquid lens is controlled to perform the first round of focusing.

[0076] S103: If there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, the theoretical optical power is input into the stroke correction curve to output the compensation stroke of the liquid lens, and the second round of focusing is performed according to the compensation stroke.

[0077] After the first round of focusing, if there is a difference between the theoretical power and the actual power, a stroke correction curve is fitted based on the difference between the theoretical power and the actual power of the first round of focusing, and the difference between the theoretical stroke and the actual stroke of the first round of focusing. Subsequently, the stroke compensation curve is used to output the compensation stroke, and the second round of focusing is performed. The key to this process is to use the stroke correction curve to correct the power deviation caused by manufacturing errors, environmental influences or nonlinear characteristics.

[0078] See also Figure 4 , which is a flow chart of a method for obtaining a stroke correction curve provided in an embodiment of the present application. Specifically, the method for obtaining a stroke correction curve can be as follows:

[0079] The first step is to simplify the mathematical model constructed in step S101. Figure 5 , which is a flow chart of a simplified method of a mathematical model provided in an embodiment of the present application. Figure 5 As shown, first, the mathematical model obtained in step S101 is discretely selected, for example, from -6.0 to 6.0, and divided according to a step size of 0.05, which will obtain a series of theoretical optical focal value D_i. Secondly, for each theoretical optical focal value D_i, the corresponding stroke Δl_i is calculated by the above formula (3). Then, the theoretical stroke Δl and the theoretical optical focal value D are graphically plotted, that is, the calculated (Δl_i, D_i) point pair is plotted on a coordinate graph, where Δl is used as the horizontal coordinate and D is used as the vertical coordinate, and the curve is fitted to a low-order function curve. See Figure 6 , which is a schematic diagram of a simplified result of a mathematical model provided in an embodiment of the present application. Figure 6 The curve fitting in is as follows:

[0080] D=4.7Δl(6)

[0081] It should be noted that after obtaining the fitted curve, the data points (Δl_i, D_i) not involved in the fitting can also be used to verify the accuracy of the fitting curve.

[0082] The second step is to determine the relationship between the theoretical stroke and the compensation stroke. First, the liquid lens 205 is zoomed according to the fitted formula (6). That is, according to the first theoretical optical focal length, the first theoretical stroke is obtained through the relationship curve between the theoretical stroke Δl and the theoretical optical focal length D. Subsequently, the movable film 203 is moved by the first theoretical stroke. At this time, the first actual optical focal length obtained is different from the first theoretical optical focal length. Theoretically, this operation should enable the liquid lens to achieve the desired theoretical optical focal length. However, due to manufacturing errors, environmental influences (such as temperature and pressure changes) or the nonlinear characteristics of the liquid lens, the actual optical focal length (i.e., the first actual optical focal length) often deviates from the first theoretical optical focal length. Finally, in order to correct this deviation, it is necessary to calculate the difference between the actual optical focal length and the theoretical optical focal length, and determine a compensation stroke Δl'-Δl based on this difference. The compensation stroke is the difference between the actual movement stroke Δl' and the theoretical stroke Δl, which indicates the additional or reduced film movement distance required to achieve the theoretical optical focal length. See Figure 7 , which is a schematic diagram of a stroke correction curve provided in an embodiment of the present application. Figure 7 The stroke correction curve in is fitted into the following formula (7):

[0083] Δl'-Δl=aD 2 -bD-0.03(7)

[0084] Among them, Δl'-Δl is the difference between the actual moving stroke and the theoretical stroke, that is, the compensation stroke, D is the theoretical optical focal length of the liquid lens, and a and b are multi-term coefficients. Through this formula, the required compensation stroke Δl'-Δl can be directly calculated according to the theoretical optical focal length D, thereby realizing precise zoom control of the liquid lens 205.

[0085] In some specific implementations, the relationship between the theoretical optical power D, the actual optical power D', the actual moving stroke Δl' and the theoretical stroke Δl may be as shown in Table 2 below:

[0086] Table 2

[0087]

[0088] In some specific implementations, based on the physical model of the liquid lens and previous experimental data, the relationship between the theoretical optical focal length D and the theoretical liquid flow rate V in the liquid tank 204 can also be established. When it is necessary to adjust the liquid lens 205 to a certain theoretical optical focal length, the required theoretical liquid flow rate can be directly calculated from this relationship. In addition, in the focusing system, a flow sensor can also be installed to monitor the actual liquid flow rate in the liquid tank 204 in real time. Subsequently, the theoretical liquid flow rate is compared with the actual liquid flow rate to obtain the flow difference ΔV, and the theoretical stroke and compensation stroke of the movable film are determined based on the flow difference ΔV. This application does not limit this.

[0089] After precise control of the above steps, the actual focal length of the liquid lens 205 will be adjusted to be close to or equal to the theoretical focal length. This process may require multiple iterations and adjustments, especially in a closed-loop control system, where the focusing device will continuously fine-tune the position of the film based on real-time feedback to achieve higher precision.

[0090] In summary, the present application discloses a focusing method for a liquid lens, which introduces a compensation stroke to correct the errors caused by the movement of the liquid lens (such as the inaccuracy of the mechanical structure, slight changes in the properties of the liquid, etc.), fine-tunes the theoretical stroke, and effectively corrects the deviation in the actual movement, thereby ensuring that the liquid lens can accurately reach the theoretical optical focal length. Therefore, by combining the precise focusing capability and the error correction mechanism, the focusing device exhibits extremely high stability and reliability during the focusing process. Whether facing complex and changeable application scenarios or long-term continuous work, it can maintain stable focusing performance to meet the actual needs of users.

[0091] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A focusing method for a liquid lens, characterized in that: The method comprises: According to the zoom structure of the liquid lens, a mathematical model is constructed, wherein the mathematical model represents the corresponding relationship between the focal length and the stroke of the liquid lens; By inputting the theoretical optical focal length into the mathematical model, a theoretical stroke of the liquid lens is output, and the liquid lens is controlled to perform a first round of focusing according to the theoretical stroke; If there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, the theoretical optical power is input into a stroke correction curve to output a compensation stroke of the liquid lens, and a second round of focusing is performed according to the compensation stroke.

2. The method according to claim 1, characterized in that The formula for outputting the theoretical stroke of the liquid lens by inputting the theoretical focal length into the mathematical model is specifically as follows: Wherein, Δl is the theoretical stroke, A and B are constants, D' is the actual optical focal length of the liquid lens, h' is the current vector height of the liquid lens, D is the theoretical optical focal length of the liquid lens, h is the target vector height of the liquid lens, R is the optical effective diameter of the liquid lens, and Δh is the vector height difference of the liquid lens.

3. The method according to claim 1, characterized in that The method of inputting the theoretical optical power into the mathematical model to output the theoretical stroke of the liquid lens comprises: By inputting the actual optical power and the theoretical optical power into the mathematical model, the actual liquid flow rate and the theoretical liquid flow rate in the liquid tank of the liquid lens are determined respectively; The theoretical stroke of the liquid lens is output according to the actual liquid flow rate and the theoretical liquid flow rate.

4. The method according to claim 3, characterized in that The formula for outputting the theoretical stroke of the liquid lens according to the actual liquid flow rate and the theoretical liquid flow rate is specifically as follows: Wherein, V2 is the theoretical liquid flow rate, V1 is the actual liquid flow rate, Δl is the theoretical stroke, r1 is the radius of the liquid tank, and r2 is the radius of the movable mechanical structure that drives the movable film to move.

5. The method according to claim 1, characterized in that The stroke correction curve is as follows: Δl’-Δl=aD 2 -bD-0.03 Wherein, Δl'-Δl is the compensation stroke, D is the theoretical optical power of the liquid lens, and a and b are multi-term coefficients.

6. The method according to claim 1, characterized in that If there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, the compensation stroke of the liquid lens is output by inputting the theoretical optical power into a stroke correction curve, including: If there is a difference between the theoretical optical power and the actual optical power of the first round of focusing, fitting a stroke correction curve according to the difference between the theoretical optical power and the actual optical power of the first round of focusing, and the difference between the theoretical stroke and the actual stroke of the first round of focusing; By inputting the theoretical optical power into a stroke correction curve, the compensation stroke of the liquid lens is output.

7. The method according to claim 1, characterized in that The step of controlling the liquid lens to perform a first round of focusing according to the theoretical stroke includes: Acquiring a focus environment parameter, wherein the focus environment parameter includes at least one of a refractive index, an Abbe number, and a temperature; According to the theoretical stroke and the focusing environment parameters, the liquid lens is controlled to perform a first round of focusing.

8. The method according to claim 1, characterized in that The liquid lens comprises a stepping motor, a push-pull rod, a film, a liquid tank and a single-aberration focus-adjustable lens imitating a human eye lens; The liquid tank is connected to the single-aberration adjustable focus lens imitating human eye lens, the refractive index of the transparent liquid in the liquid tank is the same as the refractive index of the single-aberration adjustable focus lens imitating human eye lens, and a film is attached to the liquid tank.

9. The method according to claim 8, characterized in that The transparent liquid flows mutually between the liquid tank and the single-aberration adjustable focus lens imitating human eye lens.

10. The method according to claim 9, characterized in that When the transparent liquid flows into the single-aberration adjustable-focus lens imitating human eye lens, it presents positive optical power, and when the transparent liquid flows out of the single-aberration adjustable-focus lens imitating human eye lens, it presents negative optical power.

Images