A variable-focus liquid lens based on a bellows structure and a method of using the same

Abstract

The invention discloses a variable focus liquid lens based on a bellows structure and a method for using the same, comprising a main cavity and an actuating part; the main cavity is a bellows, the interior of which is filled with a transparent fluid, the lower end is encapsulated with optical glass, the upper end is sealed and connected with an elastic film, and the upper liquid surface of the filling fluid and the elastic film are closely fitted; the actuating part comprises a stator coil and a mover permanent magnet, the mover permanent magnet is fixed to the outer wall of the bellows through a mover bracket, and the stator coil is fixed to the outside of the mover permanent magnet through a stator bracket; under electromagnetic drive, the bellows is extended or contracted along the axial direction, and the upper liquid surface of the filling fluid forms a concave interface or a convex interface with the elastic film, thereby generating a divergent or convergent effect on the outgoing light; the size and direction of the working current are controlled, and the divergence or convergence degree of the outgoing light changes continuously. The liquid lens of the invention has the advantages of a larger zoom range, a faster focusing speed, a simple structure, high focusing accuracy, and good stability.

Description

Technical Field

[0001] The invention relates to a liquid variable focus lens, and in particular to a variable focus liquid lens based on a bellows structure and a use method thereof. Background Art

[0002] Traditional zoom optical systems mainly rely on mechanical methods to adjust focal length, usually including a combination of multiple solid-state lenses. These lenses are moved relative to each other through a precise mechanical structure to change the focal length of the system. However, this design is not only complex in structure, but also easily affected by mechanical wear, impact and dust pollution, affecting the imaging quality and durability of the equipment. At the same time, mechanically driven zoom systems are usually large in size, heavy in weight, and have limited response speed, and are not suitable for application scenarios requiring high-precision and fast focusing. Summary of the invention

[0003] The purpose of the present invention is to address the defects and shortcomings of the above-mentioned prior art and provide a variable-focus liquid lens based on a bellows structure and a method of using the same. The bellows is used as the main cavity, and the magnitude and direction of the working current in the stator coil are controlled to change the degree of expansion and contraction of the bellows along the axial direction, thereby driving the interface curvature of the liquid surface on the transparent fluid to change, thereby realizing the bidirectional zoom function of the zoom lens.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a variable-focus liquid lens based on a bellows structure, the lens includes a main cavity and an actuating part, the main cavity is composed of a bellows 4, the interior of the bellows 4 is filled with a transparent fluid 7, the lower end of the bellows 4 is encapsulated with an optical glass 8, the upper end of the bellows 4 is sealed and connected to an elastic film 1, the upper liquid surface of the transparent fluid 7 and the elastic film 1 are tightly fitted, the actuating part of the variable-focus liquid lens includes a stator coil 5 and a mover permanent magnet 6, the mover permanent magnet 6 is fixed to the outer wall of the bellows 4 through a mover bracket 3, and the stator coil 5 is fixed to the outside of the mover permanent magnet 6 through a stator bracket 2.

[0005] Furthermore, the bellows 4 of the present invention can be axially retractable and radially non-deformed. The elastic properties of the bellows 4 can be adjusted by controlling the number of corrugations, the corrugation spacing, the wall thickness and the Young's modulus of the bellows 4 to improve the control accuracy and response time. When the bellows 4 contracts axially, since the transparent fluid 7 in the cavity cannot contract and the fluid volume is constant, the elastic film 1 and the upper liquid surface of the transparent fluid 7 form a convex interface, which has a converging effect on the light beam. When the bellows 4 extends axially, the upper liquid surface of the transparent fluid 7 in the tube and the elastic film 1 form a concave interface, which has a diverging effect on the light beam, that is, it has a bidirectional zoom function of a variable focus lens.

[0006] Furthermore, the diameter of the bellows 4 of the present invention can be adjusted as needed.

[0007] Furthermore, the transparent fluid 7 filled in the bellows 4 of the present invention is perfluoropolyether oil.

[0008] Furthermore, the elastic film 1 of the present invention is selected to be a polyurethane film or a PDMS film.

[0009] Furthermore, the stator bracket 2 and the mover bracket 3 of the present invention are both made of engineering plastic PC-ABS.

[0010] The present invention also provides a method for using a bellows-based variable-focus liquid lens, the method comprising the following steps:

[0011] Step 1: In the magnetic field generated by the permanent magnet 6 of the mover, the magnitude and direction of the working current in the stator coil 5 are changed to control the magnitude and direction of the Lorentz force, thereby driving the bellows 4 to contract or extend in the axial direction.

[0012] Step 2: The transparent fluid 7 in the cavity is non-contractible and the volume of the fluid is constant. When the bellows 4 contracts along the axial direction, the liquid surface of the transparent fluid 7 forms a convex interface with the elastic film 1, which converges the outgoing light. When the bellows 4 extends along the axial direction, the liquid surface of the transparent fluid 7 forms a concave interface with the elastic film 1, which makes the outgoing light beam diverge. By controlling the size and direction of the current in the stator coil 5, the liquid zoom lens based on the bellows 4 realizes bidirectional zoom within a certain zoom range.

[0013] Step 3: Once the power supply to the stator coil 5 is stopped, the Lorentz force disappears immediately, and the bellows 4 and the elastic film 1 return to their initial shapes.

[0014] Furthermore, the zoom range in the above step 2 of the present invention is -30D to +30D.

[0015] Beneficial effects:

[0016] 1. The present invention uses a bellows as the main cavity, which has the characteristics of axial expansion and contraction and radial non-deformation. By controlling the magnitude and direction of the working current in the stator coil, the expansion and contraction degree of the bellows along the axial direction is changed, thereby realizing the divergence or convergence function of the bidirectional zoom lens on light.

[0017] 2. The present invention adopts a unique structural design of the bellows, so that the aperture size of the liquid zoom lens can meet various application requirements, breaking through the bottleneck that the aperture of the existing liquid zoom lens cannot be enlarged.

[0018] 3. The liquid zoom lens of the present invention does not need to rely on a complex mechanical structure to control the change of focal length, but uses the unique axial extension or contraction characteristics of the bellows structure to achieve large-scale rapid and accurate zooming. The present invention simplifies the structural design of the liquid zoom lens and has the advantages of large zoom range, fast focusing speed, high focusing accuracy, simple manufacturing, good stability and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention.

[0020] Label description: 1-elastic film, 2-stator bracket, 3-motor bracket, 4-corrugated round tube, 5-stator coil, 6-motor permanent magnet, 7-transparent fluid, 8-optical glass.

[0021] Figure 2 This is a schematic diagram of the principle of forming a positive lens according to the present invention.

[0022] Label description: 1-elastic film, 2-stator bracket, 3-motor bracket, 4-corrugated round tube, 5-stator coil, 6-motor permanent magnet, 7-transparent fluid, 8-optical glass.

[0023] Figure 3 It is a schematic diagram of the principle of forming a negative lens in the present invention.

[0024] Label description: 1-elastic film, 2-stator bracket, 3-motor bracket, 4-corrugated round tube, 5-stator coil, 6-motor permanent magnet, 7-transparent fluid, 8-optical glass. DETAILED DESCRIPTION

[0025] The following is a detailed description of an embodiment of a variable focus liquid lens based on a bellows structure and a method of using the same, and further describes the present invention. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Persons skilled in the art may make some non-essential improvements and adjustments to the present invention based on the above invention content, which still fall within the scope of protection of the present invention.

[0026] like Figure 1As shown, the present invention provides a variable focus liquid lens based on a bellows structure, which is mainly composed of a main cavity and an actuating part. The main cavity of the lens is composed of a corrugated circular tube 4 filled with a transparent fluid. The upper end of the corrugated circular tube 4 is sealed by a highly transparent elastic film 1, and the lower end is sealed by an optical glass 8. The actuating part of the lens is fixed to the periphery of the corrugated circular tube 4. By using the principle of electromagnetic drive and controlling the magnitude and direction of the working current, the corrugated circular tube 4 is caused to shrink or stretch to different degrees along the axial direction. Since the volume of the fluid in the tube is constant and cannot be shrunk, the elastic film 1 forms a convex interface or a concave interface with different curvatures with the upper liquid surface of the transparent fluid, which produces a convergence or divergence function for the outgoing light. The specific scheme is as follows:

[0027] like Figure 2 and Figure 3 As shown, the main cavity of the lens of the present invention is mainly a corrugated circular tube 4, which is filled with a transparent fluid 7, and an optical glass 8 is used to encapsulate the lower end of the corrugated circular tube 4, while the upper end of the corrugated circular tube 4 is sealed by a highly transparent elastic film 1 to seal the transparent fluid 7. The upper liquid surface of the transparent fluid 7 and the elastic film 1 are tightly fitted to form a curved interface with a certain curvature, and the curvature of the interface determines the focal length of the liquid zoom lens. At this point, the corrugated circular tube 4, the elastic film 1, the optical glass 8 and the transparent fluid form a zoom liquid lens body; the actuating part is mainly composed of a stator coil 5 and a mover permanent magnet 6, wherein the mover permanent magnet 6 is fixed to the outer wall of the corrugated circular tube 4 through a mover bracket 3, and the stator coil 5 is fixed to the outer position of the mover permanent magnet 6 through a stator bracket 2, ensuring that the stator coil 5 and the mover permanent magnet 6 do not contact and generate a sufficiently large driving force. When the working current in the stator coil 5 changes, the driving force on the permanent magnet 6 of the mover also changes accordingly, thereby driving the corrugated circular tube 4 to extend or contract axially. Since the transparent fluid 7 in the cavity is non-contractible and the volume of the fluid is constant, when the corrugated circular tube 4 contracts axially, the elastic film 1 and the upper liquid surface of the transparent fluid 7 form a convex interface, which produces a convergence function for light, that is, it has the convergence function of a variable-focus convex lens for light beams. Similarly, when the corrugated circular tube 4 is extended axially, the elastic film 1 and the upper liquid surface of the transparent fluid 7 form a concave interface, which produces a divergence function for light, that is, it realizes the divergence function of a variable-focus concave lens for light beams. Therefore, by controlling the size and direction of the working current in the stator coil 5 and changing the axial extension and contraction degree of the corrugated circular tube 4, the bidirectional zoom function of the variable-focus liquid lens based on the bellows structure is realized, and the zoom range can reach -30D to +30D, or even higher.

[0028] The present invention comprises a corrugated circular tube 4 made of silicone, which constitutes the main cavity part of the lens, has a diameter of 20 mm and a height of 12.2 mm. Its unique corrugated structure enhances the mechanical elasticity of the material and improves the response speed. By optimizing the design of the corrugation density, the corrugation spacing and the tube wall thickness, the corrugated circular tube 4 has the characteristics of being easy to stretch axially and not deforming radially.

[0029] The transparent fluid 7 of the present invention is perfluoropolyether oil, which has good optical properties. Perfluoropolyether oil is an inert fluid and is well compatible with most materials such as plastics, silicone, glass, etc., ensuring that it will not degrade or chemically react during long-term use. Its excellent thermal stability also ensures that it can maintain good optical properties under different working temperature environments.

[0030] The high-transparency elastic film 1 of the present invention is a polyurethane film, which has the advantages of good resilience, high transparency, not easy to age, long service life and the like.

[0031] The mover bracket 3 and the stator bracket 2 of the present invention are made of PC-ABS, an engineering plastic with good impact resistance, high mechanical strength and easy processing, and 3D printing is used to reduce the difficulty of manufacturing complex structure and three-dimensional structure parts.

[0032] The driving mode of the present invention selects the electromagnetic driving mode, and the stator coil 5 and the movable permanent magnet 6 are the core components of the lens actuation part. When the size and direction of the working current in the stator coil 5 change, the driving force exerted on the movable permanent magnet 6 also changes accordingly, driving the corrugated circular tube 4 to shrink or extend axially, thereby changing the interface curvature between the elastic film 1 and the upper liquid surface of the transparent fluid, producing a converging or diverging effect on the light beam, and finally realizing the bidirectional zoom function of the zoom lens. The coil is made of pure copper material to ensure that it can work continuously and stably. The movable permanent magnet 6 is made of high magnetic permeability material iron neodymium boron to ensure that it can generate a stable strong magnetic field to provide a sufficiently large driving force.

[0033] The present invention also provides a method for using a bellows-based variable-focus liquid lens, the method comprising the following steps:

[0034] Step 1: In the magnetic field generated by the permanent magnet 6 of the mover, the magnitude and direction of the working current in the stator coil 5 are changed to control the magnitude and direction of the Lorentz force, thereby driving the corrugated tube 4 to contract or extend along the axial direction.

[0035] Step 2: The transparent fluid 7 in the cavity is non-contractible and the volume of the fluid is constant. When the corrugated tube 4 shrinks along the axial direction, the elastic film 1 forms a convex interface with the upper liquid surface of the transparent fluid 7, which converges the light, thus realizing the convergence function of the variable focus convex lens on the light beam; when the corrugated tube 4 stretches along the axial direction, the upper liquid surface of the transparent fluid 7 forms a concave interface with the elastic film 1, which diverges the light, thus realizing the divergence function of the variable focus concave lens on the outgoing light beam. By changing the magnitude and direction of the current in the stator coil 5, the liquid zoom lens based on the corrugated tube 4 has a two-way zoom capability, and its zoom range is -30D to +30D, or even higher.

[0036] Step 3: Once the power supply to the stator coil 5 is stopped, the Lorentz force disappears immediately, and the corrugated tube 4 and the elastic film 1 return to their initial shapes.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for using a bellows-based variable-focus liquid lens, characterized in that: The steps include: Step 1: In the magnetic field generated by the permanent magnet (6) of the mover, the magnitude and direction of the working current in the stator coil (5) are changed to control the magnitude and direction of the Lorentz force, thereby driving the bellows (4) to contract or extend in the axial direction; Step 2: The transparent fluid (7) in the cavity is non-contractible and has a constant volume. When the bellows (4) contracts in the axial direction, the upper liquid surface of the transparent fluid (7) and the elastic film (1) form a convex interface, which converges the outgoing light. When the bellows (4) extends in the axial direction, the upper liquid surface of the transparent fluid (7) and the elastic film (1) form a concave interface, which causes the outgoing light beam to diverge. By controlling the magnitude and direction of the current in the stator coil (5), the liquid zoom lens based on the bellows (4) realizes bidirectional zoom within a certain zoom range, and the zoom range is -30D to +30D. Step 3: Once the power supply to the stator coil (5) is stopped, the Lorentz force disappears immediately, and the bellows (4) and the elastic film (1) return to their initial shapes; A variable-focus liquid lens based on a bellows structure, wherein the main cavity of the variable-focus liquid lens is formed by a bellows, the interior of the bellows (4) is filled with a transparent fluid (7), the lower end of the bellows (4) is encapsulated with an optical glass (8), the upper end of the bellows (4) is sealed and connected to an elastic film (1), the upper liquid surface of the transparent fluid (7) and the elastic film (1) are in close contact, and the actuating part of the variable-focus liquid lens comprises a stator coil (5) and a mover permanent magnet (6), the mover permanent magnet (6) is fixed to the outer wall of the bellows (4) through a mover bracket (3), and the stator coil (5) is fixed to the outside of the mover permanent magnet (6) through a stator bracket (2); The bellows (4) can be axially retracted and radially non-deformed. The elastic properties of the bellows (4) are adjusted by controlling the number of corrugations, the corrugation spacing, the tube wall thickness and the Young's modulus, thereby improving the control accuracy and response time. When the bellows (4) contracts in the axial direction, since the transparent fluid (7) in the cavity cannot contract and the fluid volume is constant, the elastic film (1) and the upper liquid surface of the transparent fluid (7) form a convex interface, which has a convergence effect on the light beam. When the bellows (4) is extended in the axial direction, the upper liquid surface of the transparent fluid (7) in the tube and the elastic film (1) form a concave interface, which has a divergence effect on the light beam, that is, it has a two-way zoom function of a variable focus lens; The diameter of the bellows (4) can be adjusted as required; The transparent fluid (7) filled in the bellows (4) is perfluoropolyether oil; The elastic film (1) is selected to be a polyurethane film or a PDMS film; The stator bracket (2) and the mover bracket (3) are both made of engineering plastic PC-ABS.

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