Electromagnetically-driven zoom liquid lens

Abstract

The invention discloses an electromagnetically-driven zooming liquid lens which comprises a magnet piece, a multi-film structural piece, a focusing inner core and a transparent sealing bottom which are sequentially arranged from top to bottom. The magnet piece comprises a magnet and a limiting ball; the multi-film structural member comprises a hollow elastic film, a complete film, an upper annular clamping plate and a lower annular clamping plate. The structure of the focusing inner core sequentially comprises an optical cavity, an inner circular tube, a dynamic cavity, an outer circular tube and an electromagnetic driving piece from inside to outside; a communicating hole channel is arranged between the optical cavity and the dynamic cavity and filled with the same liquid; the whole device is packaged through the hollowed-out upper sealing plate, the side sheath and the hollowed-out lower sealing plate. When the electromagnetic driving part is powered on, a magnetic field is generated in the whole space of the device, the magnet is influenced by the magnetic field to generate vertical moving force so as to extrude the multi-film structural part, the dynamic cavity is extruded to extrude liquid into the optical cavity, the liquid level of the optical cavity drives the film surface type to change, the function of adjusting the focal length is achieved, the structure is simple, and use is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging technology, in particular to an electromagnetic driving zoom liquid lens. BACKGROUND

[0002] In recent years, the research and development of liquid lenses has been rapid. A liquid lens is an optical device made of one or more liquids, which can change the radius of curvature of the liquid surface or change the refractive index of the filled liquid through external control, so as to achieve the purpose of changing the optical power. It has unparalleled zooming capability of traditional optical lenses, and has the advantages of high adjustment precision, no mechanical wear, fast response speed and other revolutionary advantages. At present, it has been gradually commercialized and widely used in medicine, imaging systems, projection systems and other fields.

[0003] After nearly a decade of development, liquid lens technology has made great progress. At present, small-aperture liquid lenses with an aperture of less than 10 mm, commonly 3-5 mm, have been widely used in industrial cameras, barcode scanners, mobile phone macro focusing and other fields. However, only a few lenses can be expanded to a large aperture of 10 mm. The physical size is insufficient, which makes it impossible to break through the ceiling of its performance.

[0004] For some application scenarios that require higher requirements for light collection ability, limit resolution, system signal-to-noise ratio and design freedom, the requirements of these indicators directly conflict with the limitations of small-aperture lenses. For example, automatic driving or laser radar requires a large aperture to increase the detection distance and point cloud density, but the detection distance of small-aperture lenses is limited and cannot meet the vehicle-level safety requirements. Professional photography and broadcast television require the shallow depth of field and high light quantity brought by large-aperture lenses to ensure image quality, but small-aperture lenses cannot replace traditional large lenses. Large-aperture telescopes are needed to collect enough starlight for wavefront sensing and correction. Large-aperture lenses (such as telecentric lenses) are needed for high-end machine vision to eliminate parallax and improve measurement accuracy, which is fundamentally incompatible with small-aperture lenses.

[0005] Due to the limitations of small-aperture liquid lenses in the above aspects, the development of large-aperture liquid lens technology is a key breakthrough for the field to move to a higher level of application, which has great scientific research significance and broad application prospects. However, realizing a large aperture will inevitably bring a series of new research challenges such as image quality degradation, liquid surface gravity influence, driving stability, interface stability and vibration sensitivity, manufacturing process and packaging difficulty. SUMMARY

[0006] In view of the deficiencies of the prior art, the application discloses a liquid lens driven by electromagnetic zooming, which generates a magnetic field through an inductive hollow coil to control the up-down movement of a magnet to extrude a film structure and control the flow rate of fluid, so as to realize the function of adjustable focal length, and has simple structure and convenient use, thereby solving the problems in the background art.

[0007] To achieve the above object, the application provides the following technical scheme: a liquid lens driven by electromagnetic zooming, comprising a magnet piece, a multi-film structure piece, a focusing inner core and a transparent bottom cover arranged in sequence from top to bottom.

[0008] The magnet piece comprises a magnet and a limiting ball; the multi-film structure piece comprises a hollow elastic film, a complete film and upper and lower annular clamping plates; the limiting ball is located between the upper and lower annular clamping plates and the magnet; the structure of the focusing inner core comprises an optical cavity, an inner circular tube, a dynamic cavity, an outer circular tube and an electromagnetic driving piece in sequence from inside to outside.

[0009] The optical cavity and the dynamic cavity are separated by the inner circular tube; the electromagnetic driving piece is located at the periphery of the outer circular tube; the hollow elastic film is used for protection, and the complete film is used for completing optical deformation; the upper and lower annular clamping plates are mutually bonded with the upper end of the outer circular tube; the optical cavity and the dynamic cavity are provided with a communication hole and filled with the same liquid; the transparent bottom cover is located at the bottom of the outer circular tube, and the edge of the transparent bottom cover is mutually encapsulated with the outer circular tube.

[0010] The overall device is encapsulated by the hollow upper sealing plate, the side sheath and the hollow lower sealing plate;

[0011] When the electromagnetic driving piece is energized, a magnetic field is generated in the overall space of the device, the magnet is affected by the magnetic field to generate an up-down moving force to extrude the multi-film structure piece, the dynamic cavity is extruded to extrude liquid into the optical cavity, the optical cavity liquid surface drives the film surface to change, and focal length adjustment is realized.

[0012] Preferably, the magnet is a ring magnet.

[0013] Preferably, the electromagnetic driving piece is a hollow cylindrical structure, and the assembly composed of the outer circular tube, the multi-film structure piece and the magnet piece is accommodated in the inside of the electromagnetic driving piece.

[0014] Preferably, the upper and lower annular clamping plates are two circular clamping plates for clamping the hollow elastic film and the complete film in the middle.

[0015] Preferably, the lower clamping plate in the upper and lower annular clamping plates is fixed on the outer circular tube and the inner circular tube.

[0016] Preferably, the multi-film structure piece is the hollow elastic film and the complete film, which are two circular film structures, wherein the upper layer of the hollow elastic film is cut to remove a part of the center to form a hollow effect.

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] 1. The application has novel and simplified structure, and significantly reduced cost. The direct driving architecture of "fixed coil-movable magnet-membrane integration" is adopted, and the annular magnet as a moving component of an actuator is directly integrated on the hollow elastic membrane and the complete membrane as a deformation component. This design eliminates the complex voice coil skeleton, push rod and other intermediate transmission mechanisms in the traditional VCM scheme, and avoids the independent external pressing plate structure in the comparative document. The number of components is greatly reduced, which greatly simplifies the overall structure, reduces the assembly difficulty and manufacturing cost.

[0019] 2. The application realizes high-efficiency driving under a large aperture. Through the unique double-chamber (kinetic chamber and optical chamber) and fluid transfer mechanism, it is a high-efficiency hydraulic amplification scheme. The driving device only needs to apply a small deformation to the kinetic chamber with a large area, and can generate significant curvature change on the optical chamber with a small area through fluid transfer. This design cleverly solves the problem of requiring huge driving force to drive a large-aperture liquid surface, making low-power consumption and fast response possible.

[0020] 3. The application realizes continuous and smooth high-speed zooming. Based on the principle of electromagnetic driving, the response speed of the application can reach milliseconds. At the same time, through continuous control of the analog current signal, continuous and smooth adjustment of the focal length can be realized, avoiding the functional limitation of step-by-step and non-continuous zooming in the comparative document scheme, and having a wider application range.

[0021] 4. The application has high integration and compact device. Due to the high integration of the driving component and the optical component, the design of the application is extremely compact in axial size, which is beneficial to integration and miniaturization design in application scenarios with strict space requirements, such as high-end machine vision, automatic driving, medical endoscope, etc. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, together with the embodiments of the application, to explain the application, and do not constitute a limitation on the application.

[0023] In the drawings:

[0024] Figure 1 is a structural schematic diagram of the whole liquid lens of the application;

[0025] Figure 2 is a sectional schematic diagram of the liquid lens of the application;

[0026] Figure 3 is a structural schematic diagram of the assembled upper and lower sealing plates and side plates of the application;

[0027] Figure 4 This is a partial structural schematic diagram of the liquid lens of the present invention;

[0028] The following components are labeled in the diagram: 1. Magnet; 2. Multi-film structure; 3. Focusing core; 4. Transparent bottom cover; 1-1. Magnet; 1-2. Limiting ball; 2-1. Hollowed-out elastic membrane; 2-2. Complete membrane; 2-3. Upper and lower annular clamping plates; 3-1. Optical cavity; 3-2. Inner tube; 3-3. Dynamic cavity; 3-4. Outer tube; 3-5. Electromagnetic drive component; 3-6. Connecting channel; 5-1. Hollowed-out upper sealing plate; 5-2. Side sleeve; 5-3. Hollowed-out lower sealing plate. Detailed Implementation

[0029] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0030] Example: Figures 1-4 As shown, this invention provides an electromagnetically driven zoom liquid lens capable of achieving a large aperture. Its structure, from top to bottom, comprises a magnet 1, a multi-film structure 2, a focusing core 3, and a transparent backing 4. When the electromagnetic drive unit 3-5 is energized, it generates a magnetic field within the overall space of the device, driving the magnet 1 to move up and down, compressing the multi-film structure 2. This, combined with the transparent liquid filling the focusing core 3, achieves focus adjustment. The specific structure includes the following:

[0031] The magnet component 1 includes a magnet 1-1 and a limiting ball bead 1-2; the magnet 1-1 is a ring magnet; the multi-membrane structure component 2 includes a hollow elastic membrane 2-1, a complete membrane 2-2, and upper and lower annular clamping plates 2-3; the multi-membrane structure component 2 consists of a hollow elastic membrane 2-1 and a complete membrane 2-2, forming a two-layer circular membrane structure, wherein a portion of the center of the upper layer of the hollow elastic membrane is cut off to create a hollow effect; the upper and lower annular clamping plates 2-3 are two circular clamping plates used to clamp the hollow elastic membrane 2-1 and the complete membrane 2-2 in the middle; the lower clamping plate of the upper and lower annular clamping plates 2-3 is fixed. The focusing core 3, located on the outer tube 3-4 and inner tube 3-2, comprises, from the inside out, an optical cavity 3-1, an inner tube 3-2, a dynamic cavity 3-3, an outer tube 3-4, and an electromagnetic drive component 3-5. The optical cavity 3-1 and the dynamic cavity 3-3 are separated by the inner tube 3-2. The electromagnetic drive component 3-5 is located around the outer tube 3-4 and is a hollow cylindrical structure. The assembly consisting of the outer tube 3-4, the multi-membrane structure 2, and the magnet 1 is housed inside the electromagnetic drive component 3-5. The limiting ball 1-2 is located between the upper and lower annular clamps 2-3 and the magnet 1-1. The transparent bottom seal 4 is located at the bottom of the outer tube 3-4, and its edge is mutually encapsulated with the outer tube. The perforated elastic membrane 2-1 serves a protective function, while the intact membrane 2-2 facilitates optical deformation. The upper and lower annular clamping plates 2-3 are bonded to the upper end of the outer circular tube 3-4. A connecting channel 3-6 is provided between the optical cavity 3-1 and the dynamic cavity 3-3, and both are filled with the same liquid. The entire device is encapsulated by the perforated upper sealing plate 5-1, the side sleeves 5-2, and the perforated lower sealing plate 5-3.

[0032] During operation, when the electromagnetic drive component 3-5 is energized, it generates a magnetic field within the overall space of the device. Changes in this magnetic field cause the magnet 1-1 to produce magnetic forces in different directions, thereby squeezing the multi-film structure 2 and forcing the optical liquid from the dynamic cavity 3-3 into the optical cavity 3-1. The fluid flow velocity exerts liquid-side pressure on the perforated elastic membrane 2-1 and the intact membrane 2-2, causing them to undergo non-uniform stress and deform, thus forming an aspherical liquid lens. By adjusting the degree of electromagnetic drive, the extent to which the liquid surface in the optical cavity 3-1 causes deformation of the membrane surface can be controlled, thereby changing the surface parameters and achieving focal length range adjustment.

[0033] Specifically, the outer cylindrical tube 3-4 is a hollow cylindrical tube with a radius of 25mm and a height of 17.5mm, preferably made of PLA; the lower end face of the outer cylindrical tube 3-4 is sealed with a transparent sealing bottom 4, which in this embodiment is a quartz glass sheet with a radius of 25mm and a thickness of 1mm, preferably made of JGS2, i.e., ultraviolet optical quartz glass, or a lens can be used for encapsulation; the upper end face of the outer cylindrical tube 3-4 is sealed with a perforated elastic membrane 2-1 and a complete membrane 2-2, which are fixed by upper and lower annular clamping plates 2-3 with an inner diameter of 40mm and an outer diameter of 60mm. The selected uniform transparent elastic film has a thickness of 100μm, and its material is preferably PDMS, namely polydimethylsiloxane. The optical cavity 3-1 and the dynamic cavity 3-3 are separated by an inner circular tube 3-2 with a diameter of 20mm and a height of 18mm. Its material is preferably high borosilicate glass, but it can also be made of iron or iron-based alloy (such as silicon steel) to increase the magnetism of the electromagnetic drive component. A small groove with a height of about 1mm is cut at the bottom of the cylindrical tube as a connecting channel 3-6 to ensure that the liquid flows smoothly in the two parts of the liquid storage cavity.

[0034] The working principle of this invention is as follows: When an external control circuit applies a control current to the fixed optical cavity 3-1, the electromagnetic drive 3-5 generates a magnetic field along the optical axis in its internal space. Due to electromagnetic induction, the ring magnets located on the hollow elastic membrane 2-1 and the intact membrane 2-2 are subjected to a force along the optical axis in this magnetic field, including attractive or repulsive forces, which causes the corresponding areas of the double-layer membrane structure to deform.

[0035] When the annular magnet moves downwards, it compresses the lower kinetic cavity 3-3. The liquid within kinetic cavity 3-3, under pressure, is injected into the central optical cavity 3-1 through the bottom connecting channel 3-6. The increase in liquid volume within optical cavity 3-1 causes the central region of the upper double-layer film structure to bulge outwards, forming a convex lens surface, thus changing the lens's focal length. Conversely, when a reverse current is applied or the current is reduced, the annular magnet moves upwards, the pressure in kinetic cavity 3-3 decreases, and some of the liquid in optical cavity 3-1 flows back into kinetic cavity 3-3 through the fluid channel, reducing the curvature of the central region of the double-layer film structure. By precisely controlling the magnitude and direction of the current applied to optical cavity 3-1, rapid, continuous, and smooth adjustment of the lens's focal length can be achieved.

[0036] The lens model in this application can also be extended to a double-sided zoom liquid lens, with a flat plate separating the two sides, and each zoom film surface can be controlled independently.

[0037] The unique multilayer film structure of the optical film and deformation film of this invention achieves relative separation between the driving part of the deformation film and the optical imaging part of the optical film. Therefore, the selection of materials for the deformation film, i.e., the hollow design, which does not participate in light transmission, is more abundant. There is no need to use an optical film. The multilayer film setting can withstand repeated mechanical compression by electromagnetic drive to the maximum extent, which greatly improves the service life of the device.

[0038] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A liquid lens with electromagnetically driven zoom, characterized in that: It includes a magnet (1), a multi-film structure (2), a focusing core (3), and a transparent bottom cover (4) arranged from top to bottom. The magnetic component (1) includes a magnet (1-1) and a limiting ball (1-2); the multi-membrane structure component (2) includes a hollow elastic membrane (2-1), a complete membrane (2-2), and upper and lower annular clamping plates (2-3); the limiting ball (1-2) is located between the upper and lower annular clamping plates (2-3) and the magnet (1-1); The focusing core (3) comprises, from the inside out, an optical cavity (3-1), an inner circular tube (3-2), a dynamic cavity (3-3), an outer circular tube (3-4), and an electromagnetic drive component (3-5). The optical cavity (3-1) and the dynamic cavity (3-3) are separated by the inner circular tube (3-2). The electromagnetic drive component (3-5) is located around the outer circular tube (3-4), and the upper and lower annular clamps (2-3) are bonded to the upper end of the outer circular tube (3-4). A connecting channel (3-6) is provided between the optical cavity (3-1) and the dynamic cavity (3-3) and is filled with the same liquid. The transparent bottom seal (4) is located at the bottom of the outer tube (3-4), and the edge of the transparent bottom seal is encapsulated with the outer tube; The entire device is encapsulated by a perforated upper sealing plate (5-1), a side sleeve (5-2), and a perforated lower sealing plate (5-3); When the electromagnetic drive component (3-5) is energized, it will generate a magnetic field in the overall space of the device. The magnet (1-1) is affected by the magnetic field and generates a force to move up and down, so as to squeeze the multi-film structure component (2). The dynamic cavity (3-3) is squeezed to squeeze the liquid into the optical cavity (3-1). The liquid surface in the optical cavity (3-1) drives the film surface shape to change, thereby realizing the focal length adjustment.

2. The electromagnetically driven zoom liquid lens according to claim 1, characterized in that: The magnet (1-1) is a ring magnet.

3. The electromagnetically driven zoom liquid lens according to claim 1, characterized in that: The electromagnetic drive component (3-5) is a hollow cylindrical structure, and the assembly consisting of the outer cylindrical tube (3-4), the multi-membrane structure component (2), and the magnet component (1) is housed inside the electromagnetic drive component (3-5).

4. The electromagnetically driven zoom liquid lens according to claim 1, characterized in that: The upper and lower annular clamping plates (2-3) are two circular clamping plates used to clamp the hollow elastic membrane (2-1) and the intact membrane (2-2) in the middle.

5. The electromagnetically driven zoom liquid lens according to claim 1, characterized in that: The lower clamping plate of the upper and lower annular clamping plates (2-3) is fixed on the outer circular tube (3-4) and the inner circular tube (3-2).

6. The electromagnetically driven zoom liquid lens according to claim 1, characterized in that: The multi-membrane structure (2) consists of a hollow elastic membrane (2-1) and a complete membrane (2-2), which are two-layer circular membrane structures. The upper layer of the hollow elastic membrane has a portion of its center removed to create a hollow effect.

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