PDMS (Polydimethylsiloxane) gel type zoom lens based on piezoelectric bending sheet driving and preparation method of PDMS gel type zoom lens

Abstract

The invention provides a PDMS gel type zoom lens based on piezoelectric bending sheet driving and a preparation method of the PDMS gel type zoom lens, and belongs to the technical field of optical elements. The device comprises a packaging circular ring, a packaging cover and a piezoelectric bending sheet. The piezoelectric bending sheet serves as an actuating part of the zoom lens, the side face of the piezoelectric bending sheet is connected with the inner wall of the main cavity and the positioning column, and a lead of the piezoelectric bending sheet is led out through a lead via hole of the packaging ring. PDMS gel is filled in the packaging circular ring, and the bottom of the piezoelectric bending sheet is attached to the surface of the PDMS gel. According to the invention, the PDMS gel is used as the lens body, the piezoelectric bending sheet can generate telescopic deformation along the direction vertical to the bending sheet by controlling the size and the direction of the working voltage in the piezoelectric bending sheet, and the interface curvature of the upper surface of the PDMS gel is driven to change, so that the zooming function of the micro lens is realized. And the focal length adjustment can be realized in millisecond or even microsecond level, which is far faster than that of the traditional mechanical lens. The driving process has high controllability, the curvature and focal length of the lens can be accurately adjusted, and the lens is suitable for dynamic optical scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of optical elements, and in particular to a PDMS gel-type zoom lens driven by a piezoelectric bending piece and a preparation method thereof. Background Art

[0002] In today's era of rapid technological advancement, optical technology has penetrated numerous fields. Lenses, as core components of optical systems, have provided essential imaging and focusing functions for a wide range of applications over the past few decades. However, with the continuous advancement of technology, traditional optical zoom systems are no longer adaptable to diverse and sophisticated application scenarios due to shortcomings such as complex structure, large size, high energy consumption, easy wear, and slow response speed.

[0003] The application of piezoelectric flexures in variable-focus lenses demonstrates unique advantages, and their principles and performance characteristics determine their important position in the field of optics. Piezoelectric flexures utilize the piezoelectric effect, whereby, when an external electric field is applied, the lattice structure within a material undergoes polarization, resulting in macroscopic mechanical deformation. This deformation is linearly related to the intensity of the applied electric field, making it highly controllable. Piezoelectric flexures are used as drive elements to precisely control the deformation of the lens surface by adjusting the electric field intensity, thereby changing the curvature and focal length of the lens. This process responds extremely quickly, enabling focal length adjustments to be completed in milliseconds or even microseconds, far superior to traditional mechanical drive methods.

[0004] Piezoelectric flexors are also highly energy efficient, consuming virtually no additional power when statically maintaining a fixed focal length. This makes them ideal for portable devices with stringent power requirements, such as smartphone cameras and wearables. Furthermore, their high mechanical strength and processing flexibility enable tight integration with optical components, supporting the miniaturization and lightweight design requirements of devices. Their durability and reliability are also exceptional, with virtually no performance degradation even after long-term use under high-frequency deformation.

[0005] Piezoelectric flexures also offer excellent environmental adaptability, operating over a wide temperature range and offering excellent resistance to vibration and shock. This makes them suitable not only for consumer electronics but also for demanding applications such as aerospace, industrial inspection, and medical endoscopy. Overall, piezoelectric flexures, with their fast response, low energy consumption, high precision, miniaturization, and environmental adaptability, provide solid technical support for the application and development of variable-focus microlens technology. Summary of the Invention

[0006] In view of this, in order to solve the technical problem that traditional optical zoom systems are unable to adapt to diverse and sophisticated application scenarios due to their complex structure, large size, high energy consumption, easy wear, slow response speed and other shortcomings, on the one hand, the present invention provides a PDMS gel-type zoom lens driven by a piezoelectric bending piece, which uses PDMS gel as the lens body. By controlling the size and direction of the working voltage in the piezoelectric bending piece, the piezoelectric bending piece can produce telescopic deformation in the direction perpendicular to the bending piece, driving the interface curvature of the upper surface of the PDMS gel to change, thereby realizing the zoom function of the microlens. It can achieve focal length adjustment in milliseconds or even microseconds, which is much faster than traditional mechanical lenses. The driving process is highly controllable and can accurately adjust the lens curvature and focal length, making it suitable for dynamic optical scenes.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A PDMS gel-type zoom lens driven by a piezoelectric bending piece, comprising:

[0009] A packaging ring, serving as the main cavity of the zoom lens, with its bottom encapsulated by bottom optical glass;

[0010] A packaging cover, serving as the top package of the zoom lens, having a precision light-through hole at the top center and being encapsulated by top optical glass;

[0011] A piezoelectric bending piece, serving as the actuating portion of the zoom lens, has its side surface connected to the inner wall of the main cavity of the packaging ring and the positioning post, and its lead is led out through the lead via hole of the packaging ring;

[0012] The interior of the packaging ring is filled with PDMS gel, the bottom of the piezoelectric bending piece is in contact with the surface of the PDMS gel, and the packaging cover is locked with the packaging ring through threads.

[0013] Preferably, the PDMS gel is prepared by mixing a PDMS base liquid and a cross-linking agent in a weight ratio of 10:1-80:1.

[0014] Preferably, the side surface of the piezoelectric bending piece is adhered to the four positioning posts on the inner wall of the packaging ring, and the positive lead, the middle control electrode lead and the negative lead of the piezoelectric bending piece are led out through the lead vias of the packaging ring.

[0015] Preferably, the packaging ring and packaging cover are non-conductive rings.

[0016] Preferably, the packaging ring or packaging cover is one of a plastic ring, a glass ring and a ceramic ring.

[0017] Preferably, the piezoelectric bending piece is made of PZT5 as a base material.

[0018] On the other hand, the present invention also provides a method for preparing the above-mentioned PDMS gel-type variable focus lens driven by a piezoelectric bending piece, comprising the following steps:

[0019] Step (1), selecting a piezoelectric bending piece as the actuating part of the zoom lens;

[0020] Step (2), manufacturing the main cavity of the zoom lens, using the optical glass to encapsulate the bottom of the encapsulation ring, and filling the prepared PDMS mixed solution into the interior of the encapsulation ring;

[0021] Step (3): Install the piezoelectric bending piece in the main cavity and connect it to the inner wall of the packaging ring and the positioning column, and at the same time lead out three leads through the lead holes of the packaging ring.

[0022] Step (4): Install the optical glass on the packaging cover with a light-through hole in the center, and then connect the packaging cover to the packaging ring by tightening the threads.

[0023] Preferably, in step (2), UV-61 glue is used to bond the 3D-printed packaging ring to the optical glass to form the main cavity, and a PDMS solution prepared by mixing a PDMS base liquid with a cross-linking agent is filled into the main cavity and cured at a constant temperature.

[0024] Preferably, in step (3), a layer of UV-61 glue is applied to the edge of the piezoelectric bending piece and the connection between the inner wall of the packaging ring and the positioning column, and cured using an ultraviolet curing lamp to make the piezoelectric bending piece fit the packaging ring.

[0025] Preferably, in step (4), a layer of UV-61 glue is applied to the wall of the central light-through hole at the top of the packaging cover, which is then cured using a UV curing lamp, and optical glass is bonded to the light-through hole.

[0026] Preferably, in step (5), the packaging cover on which the optical glass is mounted is connected to the packaging ring by tightening the threads, thereby producing the variable focus microlens.

[0027] Preferably, the method further includes step (6), applying an external voltage to drive the lens: utilizing the piezoelectric effect of the piezoelectric bending piece to apply positive and negative DC voltages to cause the piezoelectric bending piece to bend upward or downward, thereby generating corresponding tension or pressure to change the curvature radius of the zoom lens to change the focal length.

[0028] The present invention has the following beneficial effects compared to the prior art:

[0029] (1) The present invention provides a PDMS gel-type zoom lens based on piezoelectric bending plate driving technology. The lens body is made of PDMS (polydimethylsiloxane) gel with excellent optical properties and a light transmittance of up to 97%. By precisely controlling the voltage applied to the piezoelectric bending plate, the piezoelectric effect is used to cause it to produce controllable deformation, thereby driving the surface curvature of the PDMS gel to change and achieve focal length adjustment. The advantage of this technology lies in its extremely high response speed (millisecond to microsecond level) and precise controllability. Its performance far exceeds that of traditional mechanical lenses, and it is very suitable for dynamic optical applications that require fast and precise adjustment.

[0030] (2) Customizable material mechanical properties: The elastic modulus of PDMS gel can be precisely adjusted by changing the ratio of substrate to crosslinker. This allows for a smooth transition from an ultra-soft gel suitable for large deformations to a semi-rigid elastomer that maintains stability, thus enabling customization to meet the specific requirements for flexibility or rigidity in different applications.

[0031] (3) Low power consumption and high reliability: The piezoelectric drive system has extremely low energy consumption, especially when in static state, which is almost zero power consumption, making it very suitable for portable devices. At the same time, the core materials (piezoelectric sheet and PDMS) are highly durable, with minimal performance degradation under long-term high-frequency deformation, ensuring long-term stable operation of the device.

[0032] (4) Miniaturization and lightweight design: Compared with traditional mechanical lenses, the structure of the present invention is extremely compact and lightweight, making it easy to integrate into space- and weight-constrained applications such as micro-optical systems, mobile devices, and wearable technologies.

[0033] (5) Excellent environmental adaptability: The present invention combines PDMS material, which is chemically resistant and adaptable to a wide temperature range of -40°C to 200°C, with a piezoelectric drive system that is resistant to vibration and shock. This enables the lens to maintain highly stable optical performance in harsh environments such as sudden temperature changes, chemical erosion, or physical shock.

[0034] (6) Overcoming the shortcomings of traditional lenses: The PDMS gel used in this invention fundamentally solves the leakage problem of liquid lenses and is unaffected by gravity and electromagnetic interference. In addition, it can provide a wider zoom range and higher-quality imaging, effectively avoiding the image distortion problem of traditional solutions.

[0035] (7) Low cost and easy processing: PDMS material is low in cost and has a simple processing technology. It can use molds or micro-nano technology to achieve low-cost, large-scale production of complex optical structures, and has great market application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the overall structure of the zoom lens;

[0037] Figure 2 Schematic diagram of the packaging ring structure;

[0038] Figure 3 Schematic diagram of the packaging cover structure;

[0039] Figure 4 Schematic diagram of the structure of the piezoelectric bending piece;

[0040] Figure 5 Schematic diagram of the driving principle of the piezoelectric bending piece;

[0041] Figure 6 is a preparation flow chart of the present invention;

[0042] Among them: 1. Packaging cover; 11. Preload ring; 12. Light hole; 2. Packaging ring; 21. Positioning column; 22. Lead via; 3. Bottom optical glass; 4. Top optical glass; 5. Piezoelectric bending piece; 51. Positive lead; 52. Middle control electrode lead; 53. Negative lead; 6. PDMS gel. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work shall fall within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0045] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "mounted / connected," and "connected" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention in specific circumstances.

[0046] like Figure 1-6 As shown, the present invention provides a PDMS gel-type zoom lens driven by a piezoelectric bending piece 5, comprising:

[0047] The encapsulation ring 2, which serves as the main cavity of the zoom lens, is encapsulated at the bottom by bottom optical glass 3 and at the top by right encapsulation cover 1. The interior of the encapsulation ring 2 is filled with PDMS gel 6. This PDMS gel 6 is preferably formed by mixing a PDMS base liquid and a crosslinking agent in a weight ratio of 10:1 to 80:1, and then curing at a constant temperature.

[0048] The packaging cap 1, serving as the top package of the zoom lens, has a light hole 12 at its top center and is encapsulated by top optical glass 4. The packaging ring 2 and packaging cap 1 are preferably non-conductive rings. Specifically, the packaging ring or packaging cap is one of a plastic ring, a glass ring, and a ceramic ring.

[0049] The piezoelectric bending piece 5, which serves as the actuating element of the zoom lens, has its sides connected to the inner wall of the packaging ring and the positioning post 21. Its positive lead 51, intermediate control electrode lead 52, and negative lead 53 are led through the lead vias 22 of the packaging ring 2. Its bottom is bonded to the surface of the PDMS gel 6. Preferably, the bottom of the piezoelectric bending piece 5 is bonded to the surface of the uncured PDMS gel. Heating is used to tightly bond the bottom of the piezoelectric bending piece 5 to the PDMS gel 6. The sides of the piezoelectric bending piece 5 are preferably bonded to the inner wall of the packaging ring and the positioning post 21 using UV glue, which is cured by ultraviolet light. The piezoelectric bending piece 5 is preferably made of PZT5 as the substrate.

[0050] The above-mentioned PDMS gel-type zoom lens driven by the piezoelectric bending piece 5 provided by the present invention adopts PDMS gel 6 as the optical medium. By controlling the magnitude and direction of the working voltage in the piezoelectric bending piece 5, the piezoelectric bending piece 5 produces a telescopic deformation along the direction perpendicular to the piezoelectric bending piece, driving the interface curvature of the upper surface of the PDMS gel 6 to change, thereby realizing the zoom function of the microlens.

[0051] PDMS (polydimethylsiloxane) gel is an ideal material for flexible optical devices, and its core advantage lies in its combination of excellent optical and mechanical properties. It has a visible light transmittance of up to 97% and an adjustable refractive index, ensuring high-definition imaging quality. At the same time, its inherent flexibility and low elastic modulus enable it to precisely change shape under external forces, allowing it to be used to manufacture dynamic optical components that can be zoomed or bent. In addition, PDMS also combines excellent durability, environmental stability, low cost, and ease of batch processing. Its surface can be easily functionalized to achieve specific properties such as waterproofing and anti-reflection, and its good air permeability also avoids optical distortion. Taking these characteristics into account, PDMS, with its comprehensive advantages in performance, cost, and functionality, has shown great application potential in flexible lenses, zoom systems, and micro-optical devices, and is an important material driving the development of modern optical technology.

[0052] The elastic modulus of PDMS (polydimethylsiloxane) gel can be flexibly adjusted by changing the ratio of substrate to crosslinker:

[0053] By precisely controlling the ratio of PDMS substrate to crosslinker, its mechanical properties can be fully customized. For example, at a low ratio of 80:1, PDMS exhibits an ultra-flexible gel state, suitable for applications requiring extreme deformation. When the ratio is increased to 40:1, the material maintains high flexibility while achieving an even better balance, making it ideal for flexible lenses. A ratio of 20:1 provides a moderate elasticity that balances flexibility and stability. The most widely used standard ratio, 10:1, offers the best balance of flexibility, mechanical strength, and processability. Finally, when the ratio is further increased to 5:1 and 2:1, the rigidity and mechanical stability of PDMS are significantly enhanced, transforming it into a hard elastomer suitable for the fabrication of rigid structures and highly stable molds. By adjusting the ratio of substrate to crosslinker, PDMS can achieve customized properties between flexibility and rigidity, providing flexible and efficient solutions for the fields of optics, biomedicine, electronics, and microfluidics.

[0054] The present invention provides a gel polymer based on a mixture of a PDMS base liquid and a cross-linking agent, wherein the mixing ratio is between 10:1 and 80:1 (weight ratio). Within this ratio range, the cured PDMS gel exhibits a unique state between liquid and solid, and possesses soft and elastic physical properties. Driven by a piezoelectric bending plate, the PDMS gel can change its radius of curvature, thereby adjusting the lens's ability to refract light and achieve an optical zoom function. In addition, by adjusting the mixing ratio, the elastic modulus of the PDMS gel can be precisely controlled: gels with a larger ratio have a lower elastic modulus and better elasticity, which are suitable for lens designs with a larger focal length variation range; while gels with a smaller ratio have a higher elastic modulus and stronger rigidity, which are suitable for edge zoom lens designs with a faster response time. Compared with the prior art, the present technical solution uses PDMS gel as an optical medium, which effectively solves the problems of traditional liquid medium lenses, such as leakage, poor mechanical stability, limited focal length variation range, large distortion, and poor imaging quality. Specifically, liquid lenses in the prior art are divided into two categories: one is a liquid lens based on the deformation of a flexible membrane, which has a wide zoom range, but has problems such as easy leakage, being affected by gravity, electromagnetic interference, slow response speed, large size, and excessive driving voltage; the other is a liquid crystal lens based on refractive index change. Although it has the advantages of small size and adjustable focal length, it also has defects such as slow response speed, low light transmittance, susceptibility to temperature and environmental changes, and unstable performance. In addition, the optical quality of liquid crystal lenses may be limited by problems such as aberrations and scattering, and their manufacturing process is complex and costly. Due to the need for electric field drive, liquid crystal lenses also have long-term use limitations in terms of power consumption and reliability. These factors limit their application in high-precision or harsh environments.

[0055] The present invention precisely controls the voltage of the piezoelectric bending plate and the Young's modulus of the PDMS gel to adjust its mechanical properties, thereby improving control accuracy, response speed, and adjustable focusing range. When the piezoelectric bending plate is pressed downward in a direction perpendicular to the plate, the volume of the PDMS gel in the cavity remains unchanged, forming a convex interface on its surface, which converges the light beam. Conversely, when the piezoelectric bending plate is pulled upward in a direction perpendicular to the plate, the volume of the cavity increases, the PDMS gel fills the empty space, and a concave interface forms on the surface, which diverges the light beam.

[0056] like Figure 5 As shown, on the other hand, the present invention also provides a method for preparing the above-mentioned PDMS gel-type zoom lens driven by a piezoelectric bending piece, comprising the following steps:

[0057] Step (1): Select the piezoelectric bending piece 5 as the actuating part of the zoom lens. Figure 4 As shown, the present invention selects a piezoelectric bending piece 5 as the actuating part (driving device) of the variable focus lens. The piezoelectric bending piece 5 is preferably made of PZT5 as a base material. According to different models, its outer diameter is 20mm to 40mm, the inner diameter is 4 to 8mm, and the height is 0.7mm to 1.25mm. The other size can be customized and can be selected according to actual needs.

[0058] The control method of the piezoelectric bending piece 5 is as follows:

[0059] like Figure 4 As shown, the piezoelectric bending piece 5 used in the present invention is exemplarily shown to be connected to three leads, namely the positive lead 51, the middle control electrode lead 52, and the negative lead 53. Different wiring methods can be adopted according to actual conditions. One is a three-wire drive, which can bend upward and downward. The positive lead 51 is connected to +100V, the negative lead 53 is connected to -100V, and the middle control electrode 52 lead voltage Vn is between -100V and +100V. It bends upward when it is between 0 and +100V, and bends downward when it is between -100V and 0. The second is a two-wire drive, which can only bend in one direction. The negative lead 53 is connected to 0V, the middle control electrode lead 52 is connected to 0V, the positive lead 51 controls the voltage range to 0 to 200V, and the bending piece bends upward. The displacement during unipolar use is half of that during bipolar use. The corresponding schematic diagram is shown as follows. Figure 5 shown.

[0060] Step (2) of making the main cavity of the zoom lens: the bottom optical glass 3 is used to encapsulate the bottom of the encapsulation ring 2, and the prepared PDMS gel 6 is filled into the interior of the encapsulation ring 2. Preferably, UV-61 glue is used to bond the 3D-printed encapsulation ring 2 to the bottom optical glass 3 with a radius of 20 mm to form the main cavity of the microlens. The weight ratio of PDMS base liquid to crosslinker can be adjusted according to actual usage conditions. PDMS with a low crosslinker ratio (e.g., 80:1) is extremely soft, approaching a gel state, making it suitable for scenarios requiring large deformation and ultra-flexibility without frequent displacement, such as flexible sensors, dynamic optical lenses, and high-depth-of-field microscopes. A 40:1 ratio maintains high flexibility while exhibiting improved elasticity and balance, making it an ideal choice for flexible lenses and microfluidic devices. A 20:1 ratio provides moderate elasticity, balancing flexibility and stability, making it suitable for multifunctional optical devices. Lower ratios (e.g., 80:1) result in greater PDMS gel deformation and a wider range of focal length variation. Higher ratios (e.g., 20:1) provide greater stability and faster response. After preparing the PDMS gel, use a glass rod, syringe, or micropipette to add the stirred PDMS gel to the lens chamber. After vacuum degassing for 30-60 minutes to eliminate bubbles, place the gel in a constant-temperature drying oven at 70°C for 4 hours to cure.

[0061] Step (3): Install the piezoelectric bending piece 5 in the main cavity of the packaging ring 2 and connect it to the inner wall of the main cavity of the packaging ring 2 and the positioning post 21. The positive lead 51, the intermediate control electrode lead 52, and the negative lead 53 of the piezoelectric bending piece 5 are led out through the lead via 22 of the packaging ring 2. The piezoelectric bending piece 5 is placed in the main cavity after the PDMS gel 6 is added but not yet cured, and a layer of UV-61 glue is applied to its edge, the packaging ring 2, and the positioning post 21. A UV curing lamp is then used to cure the piezoelectric bending piece 5 to connect it to the packaging ring 2. The piece is then placed in a constant temperature drying oven at 70°C for 2 hours until it is completely cured.

[0062] In step (4), the top optical glass 4 is mounted on the package cover 1 with a precise light hole 3 at the center. The top optical glass 4 is then screwed onto the upper open end of the package ring 2, so that the preload ring 11 on the package cover 1 applies a preload force to the piezoelectric bending piece 5. The package cover 1 not only seals the cavity and protects the PDMS gel 6 from contamination, but the light hole 3 at the center also serves as the system's aperture stop, precisely defining the beam diameter passing through the lens.

[0063] The present invention further includes step (5), applying an external voltage to drive the lens: utilizing the piezoelectric effect of the piezoelectric bending piece 5, applying positive and negative DC voltages, so that the piezoelectric bending piece 5 bends up and down or stretches up and down. Due to the incompressibility of the volume of the PDMS gel in the lens cavity, the piezoelectric bending piece 5 squeezes the surrounding PDMS gel 6 onto the central through hole or disperses the PDMS gel 6 in the central through hole to the surrounding area, so that the curvature radius of the zoom lens changes to change the focal length.

[0064] The technical solution of the present invention is described in detail below with reference to specific embodiments.

[0065] Example 1

[0066] (1) Select lens drive (actuating part): Select piezoelectric bending piece 5 as the actuating part of the zoom lens. The piezoelectric bending piece 5 is made of a stack of multi-layer piezoelectric ceramic substrates and co-fired. The displacement of this piezoelectric bending piece 5 is much larger than that of an ordinary dual-chip. The piezoelectric bending piece 5 used in this embodiment is the PZT5 piezoelectric bending piece 5 of Xin Mingtian Company, which is connected to three leads, the positive lead 51, the middle control electrode lead 52, and the negative lead 53. Different wiring methods can be adopted according to actual conditions. One is a three-wire drive, which can bend upward and downward. The positive pole is connected to +100V, the negative pole is connected to -100V, and the middle control electrode voltage V n It bends upwards when the voltage is between -100V and +100V and bends downwards when the voltage is between -100V and 0V. The second is a two-wire drive, which can only bend in one direction. The negative lead 53 is connected to 0V, the middle control electrode lead 52 is connected to 0V, and the positive lead 51 controls the voltage range to 0~200V. The bending piece bends upwards. The displacement when using unipolarity is half of that when using bipolarity. The corresponding schematic diagram is as follows Figure 5 As shown, the piezoelectric bending piece 5 has a diameter of 30 mm, a thickness of 1.25 mm, and a central aperture of 6 mm. The maximum displacement at the center position is ±78 microns. The driving voltage is ±100 or 200 V.

[0067] (2) Preparation of PDMS gel: drop 0.05 g of cross-linking agent into a reagent bottle, then add 2 g of PDMS base liquid into the reagent bottle and stir evenly using a magnetic stirring table to allow the cross-linking agent and PDMS base liquid to blend into one; finally, let it stand or vacuum degas for 30 minutes.

[0068] (3) Making the lens body: Use UV-61 glue to bond the 3D-printed packaging ring 2 to the bottom optical glass 3 with a radius of 20 mm to form the main cavity of the microlens. Fill the PDMS gel 6 into the cavity as the optical medium of the flexible lens body. The weight ratio of the base liquid to the cross-linking agent of PDMS can be prepared according to demand. The present invention uses a PDMS gel with a base liquid to cross-linking agent weight ratio of 40:1 as the lens body medium of the lens. First, use a glass rod to pour the evenly stirred PDMS gel into the cavity. Then, place it in a vacuum drying oven for 30 minutes to remove bubbles. Finally, place it in a constant temperature oven at 70°C and bake for 4 hours.

[0069] (4) Making a PDMS gel type zoom lens: After adding PDMS gel 6 and heating it in a constant temperature drying oven at 70°C for 4 hours, put the piezoelectric bending piece 5 into the lens cavity, and apply a layer of UV-61 glue on its surface edge, the inner wall of the packaging ring 2 and the positioning column 21, and then use a UV curing machine to cure it, and then put it into the oven at 70°C for constant temperature curing for 2 hours to ensure the stability of the piezoelectric bending piece 5 during the voltage application process. Secondly, the packaging ring 2 with the piezoelectric bending piece 5 installed is packaged with the packaging cover 1. Finally, the PDMS gel type zoom microlens driven by the piezoelectric bending piece 5 is completed. When the positive lead 51 is connected to +100V, the negative lead 53 is connected to -100V, and the voltage of the middle control electrode lead 52 is V n At 80V, the response time of the lens is 2.448ms; when the positive electrode is connected to +100V, the negative electrode is connected to -100V, and the middle electrode control voltage V n It bends upwards at 0~+100V, and the focusing range is -∞~-318mm; it bends downwards at -100V~0, and the focusing range is 173mm~∞.

[0070] Example 2

[0071] Same as Example 1, except that the weight ratio of PDMS base liquid to cross-linking agent is 60:1.

[0072] When the positive lead 51 is connected to +100V, the negative lead 53 is connected to -100V, and the voltage of the middle control electrode lead 52 is V n At 80V, the response time of the lens is 3.095ms; when the positive lead 51 is connected to +100V, the negative lead 53 is connected to -100V, and the voltage of the middle control electrode lead 52 is V n It bends upwards at 0~+100V, and the focusing range is -∞~-80mm; it bends downwards at -100V~0, and the focusing range is 87mm~∞.

[0073] Example 3

[0074] Same as Example 1, except that the weight ratio of PDMS base liquid to cross-linking agent is 80:1.

[0075] When the positive lead 51 is connected to +100V, the negative lead 53 is connected to -100V, and the voltage of the middle control electrode lead 52 is V n At 80V, the response time of the lens is 5.895ms; when the positive electrode is connected to +100V, the negative electrode is connected to -100V, and the middle electrode control voltage V n It bends upwards at 0~+100V, and the focus range is -∞~-24mm; it bends downwards at -100V~0, and the focus range is 18mm~∞.

Claims

1. A PDMS gel-type zoom lens driven by a piezoelectric bending plate, characterized in that: include: A packaging ring, serving as the main cavity of the zoom lens, with its bottom encapsulated by bottom optical glass; A packaging cover, serving as the top package of the zoom lens, having a light-through hole at the top center and being packaged by top optical glass; A piezoelectric bending piece, serving as the actuating portion of the zoom lens, has its side surface connected to the inner wall of the main cavity of the packaging ring and the positioning post, and its lead is led out through the lead via hole of the packaging ring; The interior of the packaging ring is filled with PDMS gel, the bottom of the piezoelectric bending piece is in contact with the surface of the PDMS gel, and the packaging cover is locked with the packaging ring through threads.

2. The PDMS gel-type zoom lens driven by a piezoelectric bending piece according to claim 1, characterized in that: The PDMS gel is prepared by mixing a PDMS base liquid and a cross-linking agent in a weight ratio of 10:1-80:

1.

3. The PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to claim 1, characterized in that: The side surface of the piezoelectric bending piece is adhered to the four positioning posts on the inner wall of the packaging ring, and the positive lead, the middle control electrode lead and the negative lead of the piezoelectric bending piece are led out through the lead vias of the packaging ring.

4. The PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to claim 1, characterized in that: The packaging ring and the packaging cover are non-conductive rings.

5. The PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to claim 4, characterized in that: The packaging ring or packaging cover is one of a plastic ring, a glass ring and a ceramic ring.

6. The PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to claim 1, characterized in that: The piezoelectric bending piece is made of PZT5 as a base material.

7. A method for preparing a PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to any one of claims 1 to 6, characterized in that: The steps include: Step (1), selecting a piezoelectric bending piece as the actuating part of the zoom lens; Step (2), making the main cavity of the zoom lens, using the optical glass to encapsulate the bottom of the encapsulation ring, and filling the prepared PDMS gel into the interior of the encapsulation ring; Step (3), installing the piezoelectric bending piece in the packaging ring and connecting it to the inner wall of the packaging ring and the positioning column, and leading the three leads through the lead holes of the packaging ring; Step (4): Install the optical glass on the packaging cover with a light-through hole in the center, and then connect the packaging cover to the packaging ring by tightening the threads.

8. The method for preparing a PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to claim 7, characterized in that: In step (2), the packaging ring is bonded to the optical glass using UV-61 glue to form the main cavity, and the PDMS gel prepared by mixing the PDMS base liquid and the cross-linking agent is filled into the main cavity and cured at a constant temperature.

9. The method for preparing a PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to claim 7, characterized in that: In step (3), a layer of UV-61 glue is applied to the edge of the piezoelectric bending piece and the connection between the inner wall of the packaging ring and the positioning column, and a UV curing lamp is used to cure it so that the piezoelectric bending piece fits the packaging ring.

10. A method for preparing a PDMS gel-type variable focus lens driven by a piezoelectric bending piece according to any one of claims 7 to 9, characterized in that: The invention also includes step (5), applying an external voltage to drive the lens: utilizing the piezoelectric effect of the piezoelectric bending piece, applying positive and negative DC voltages to make the piezoelectric bending piece bend upward or downward, thereby generating corresponding tension or pressure to change the curvature radius of the zoom lens to change the focal length.

Images