A shape memory microlens array and multi-channel non-contact light-controlled switch

Abstract

The present invention belongs to the field of optical devices, and specifically relates to a shape memory microlens array and a multi-channel non-contact optical switch. The preparation method of MLA includes: 1. Preparing a concave MLA template by femtosecond laser processing and chemical etching; 2. Mixing epoxy resin and curing agent in proportion, and obtaining a transparent SMP material after vacuuming; 3. Covering the concave MLA template with the transparent SMP material, curing and demolding, to obtain a shape memory MLA. The multi-channel non-contact optical switch includes: a light control box, a laser, a lens array, a laser beam expander, a photosensitive array, a displacement mechanism, a flattening mechanism, a temperature control mechanism, and a controller. The laser emitted by the laser reaches the starting threshold of the optical switch in the photosensitive array after being expanded by the laser beam expander and focused by the lens array; therefore, the switching state of the optical switch can be adjusted by changing the shape of the lens array. The present invention solves the problems of the existing MLA being difficult to manufacture, high cost, and limited application value.

Description

Technical Field

[0001] The present invention belongs to the field of optical devices, and in particular relates to a shape memory microlens array and a multi-channel non-contact optically controlled switch. Background Art

[0002] A microlens array (MLA) consisting of hundreds of microlenses is a typical small-size, highly integrated optical component. To date, MLA has been widely used in fields such as optical imaging, infrared guidance, and optical sensing. In some advanced optical systems, MLA often plays a vital role in achieving their advanced optical performance. Each microlens unit of MLA operates independently and works as a whole, thereby achieving light manipulation, optical phase modulation, resolution improvement, and aberration correction. In recent years, advances in micro / nano-fabrication technology have promoted the rapid development of micro-optical device manufacturing methods. Various types of MLA can be successfully manufactured through advanced additive and subtractive manufacturing technologies.

[0003] In order to achieve adjustable imaging capabilities using microlens arrays, some technicians have integrated more functional components into MLAs, which can achieve mechanical deformation or adjust the electric / optical field, but this also increases the size and complexity of the system. Other technicians have changed the refractive index of MLAs by changing the pH of the medium solution. However, these methods still have problems such as high power consumption, non-deformable rigid bodies, large and complex system structures, and limited focal length adjustability. In addition, the combination of smart materials and microlens structures can bring obvious advantages, including programmable deformation, remote operation, and multimodal adjustability. However, unlike photopolymers that allow flexible structures, the fabrication of tunable MLAs based on transparent smart materials is still rare.

[0004] Some researchers have proposed combining memory materials with microlens arrays to develop microlens arrays with shape memory capabilities. This improves the performance of microlens arrays and reduces the difficulty of adjusting them. However, existing shape memory microlens arrays are difficult to manufacture, have low yields, and are expensive. Furthermore, research on the application of shape memory microlens arrays is still in its infancy, with limited practical applications. Developing new microlens arrays and new applications based on them remains a hot research area for those skilled in the art. Summary of the Invention

[0005] In order to solve the problems of existing shape memory microlens arrays such as difficulty in manufacturing, high cost and limited application value, the present invention provides a shape memory microlens array and a multi-channel non-contact light-operated switch.

[0006] The technical solution provided by the present invention is:

[0007] A shape memory microlens array is prepared from a shape memory polymer (SMP), and the preparation method comprises the following steps:

[0008] 1. Preparation of concave MLA template

[0009] (1) Quartz glass is processed by a femtosecond laser processing system to form pits on the quartz glass that match the size and spatial distribution of each lens unit in the shape memory microlens array.

[0010] (2) The quartz glass with the pit array processed is chemically etched using a 20% HF etching solution to obtain a concave MLA template with a smooth and uniform surface.

[0011] 2. Preparation of Transparent SMP Materials

[0012] (3) The components for preparing the transparent shape memory material are mixed in a predetermined mass ratio and stirred thoroughly to ensure that the two are evenly mixed.

[0013] (4) The mixture is subjected to vacuum treatment in an internal vacuum machine to obtain a transparent SMP material from which air and volatile substances are removed.

[0014] 3. Reconstructing Shape Memory Microlens Arrays

[0015] (5) The transparent SMP material is evenly coated on the concave MLA template.

[0016] (6) The coated template was placed on a heating platform and heated at 65°C for 3 h to fully solidify the transparent SMP material to obtain a shape memory microlens array.

[0017] (7) The cured shape memory microlens array and the MLA template were transferred to an infrared lamp at 85°C. After irradiation for 2-3 minutes, the softened shape memory microlens array was demolded.

[0018] As a further improvement of the present invention, the light source of the femtosecond laser processing system is a 1030 nm femtosecond laser. During the processing, the pulse duration is 100 fs and the repetition frequency is 100 kHz.

[0019] As a further improvement of the present invention, the quartz after chemical etching in step (2) is cleaned and dried respectively to obtain the desired concave MLA template.

[0020] As a further improvement of the present invention, in step (3), the components used to prepare the transparent shape memory material include epoxy resin E51 and epoxy resin curing agent D230, and the mass ratio of the two is 3:1.

[0021] As a further improvement of the present invention, in step three, the shape memory microlens array completes the reconstruction process in a dust-free environment.

[0022] The present invention also includes a multi-channel non-contact optical switch, which includes: an optical control box, a laser, a lens array, a laser beam expander, a photosensitive array, a displacement mechanism, a flattening mechanism, a temperature control mechanism, and a controller.

[0023] The light control box includes a tubular darkroom with a square cross-section. The laser is located at one end of the darkroom in the light control box. The laser is used to emit laser light from one end of the darkroom to the other end; the laser light path emitted by the laser is along the axis of the darkroom. The lens array is installed in the middle of the darkroom in the light control box and is perpendicular to the extension direction of the darkroom. The lens array contains multiple lens units; the lens array adopts the shape memory microlens array as mentioned above. The lens array is a flexible lens array and has the ability to restore its own deformation under specified temperature conditions. The laser beam expander is located between the laser and the lens array, and the laser beam expander is used to expand the laser emitted by the laser into a collimated beam that can cover the lens array.

[0024] The photosensitive array is located on the other side of the darkroom away from the laser. The photosensitive array includes a number of photosensitive units corresponding to the number of lens units in the lens array. Each photosensitive unit in the photosensitive array is located at the focus of each lens unit in the lens array.

[0025] The displacement mechanism is used to move the photosensitive array along the extension direction of the light control box, thereby adjusting the relative distance between the photosensitive array and the lens array.

[0026] The flattening mechanism, located in the light control box, is used to apply stress to the lens array to cause it to undergo plastic deformation. The temperature control mechanism is used to adjust the temperature of the lens array to drive the lens array to return to its natural state after plastic deformation.

[0027] The controller is electrically connected to the laser, the displacement mechanism, the flattening mechanism and the temperature control mechanism, and is used to adjust the operating states of the laser, the displacement mechanism, the flattening mechanism and the temperature control mechanism.

[0028] In the multi-channel, contactless optical switch of the present invention, each photosensitive unit in the photosensitive array functions as an independent optical switch. Laser light emitted by the laser reaches the activation threshold of the optical switch after being expanded by a laser beam expander and focused by a lens array. When the lens array is in a deformed state, the optical switch is closed; when the lens array is in its neutral state, the optical switch is open.

[0029] As a further improvement of the present invention, the flattening mechanism includes a first steering plate, a second steering plate, and a drive assembly. The first steering plate and the second steering plate are respectively located on either side of the lens array; the drive assembly is configured to drive the first steering plate and the second steering plate to rotate synchronously and switch between the first state and the second state.

[0030] In the first state, the first and second steering plates rotate inward to a position parallel to the lens array to clamp the lens array and cause plastic deformation of the lens array. In the second state, the first and second steering plates rotate outward to a position perpendicular to the lens array, thereby moving away from the laser light path.

[0031] As a further improvement of the present invention, the temperature control mechanism adopts an infrared heater, which includes an infrared light source and a driving circuit. The driving circuit is used to adjust the luminous power of the infrared light source; the irradiation direction of the infrared light source points to the lens array.

[0032] As a further improvement of the present invention, the multi-channel non-contact light-controlled switch further includes a temperature sensor; the temperature sensor is located in a darkroom in the light-controlled box, the temperature sensor is electrically connected to the controller, and the controller measures the ambient temperature in the darkroom through the temperature sensor.

[0033] The technical solution provided by the present invention has the following beneficial effects:

[0034] This invention utilizes femtosecond laser processing combined with chemical etching to produce MLA templates, and a transfer printing method to enable batch processing of shape memory microlens arrays. The paper cup method provided by this invention not only improves the processing accuracy and spatial resolution of microlens arrays but, more importantly, fundamentally alters the interaction mechanism between laser and material. This processing method offers extremely high precision and applicability, improving product yield and reducing processing costs, making it suitable for mass production and application.

[0035] The shape memory microlens array provided by the present invention combines a microlens structure with a reconfigurable smart material, exhibiting significant advantages such as programmable deformation, remote operation capability, and multimodal adjustability. The reconfigurable MLA has good surface quality and optical performance. At a specific transition temperature, the shape memory MLA can be flexibly molded into any temporary structure, such as a flat MLA. This feature enables the focusing and imaging behavior of the MLA to be adjusted in a controllable manner. By triggering the reconfiguration process through heating, the MLA can quickly restore its optical performance, achieving dynamic adaptation and efficient application.

[0036] Based on the optical performance and memory recovery characteristics of the shape memory microlens array processed by the present invention, the present invention further developed a non-contact light-controlled switch that can be synchronously controlled in multiple channels. This special optical device can realize light-controlled non-contact switch control, and therefore has broad practical prospects in fields such as electronic technology and display. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of the steps of the method for preparing the shape memory microlens array provided in Example 1 of the present invention.

[0038] Figure 2 This is a schematic diagram of the principle of a multi-channel non-contact optically controlled switch provided in Example 2 of the present invention.

[0039] Figure 3 This is a schematic diagram of the module connection of the electronic control part of a multi-channel non-contact optical switch.

[0040] Figure 4 This is the working mode diagram of the flattening mechanism in different states.

[0041] Figure 5 This is a working principle diagram of the flattening mechanism driven by a magnetic control system.

[0042] Figure 6 Schematic diagram of the principle of a multi-channel non-contact light-controlled switch including a temperature sensor.

[0043] Figure 7 Optical microscope image of the reconfigurable MLA prepared in the verification experiment.

[0044] Figure 8 To verify the imaging performance of MLA in the experiment.

[0045] Figure 9 This is the focal spot image of the MLA used in the verification experiment.

[0046] Figure 10 To verify the resolution test results of MLA in the experiment.

[0047] Figure 11 Comparison of the microscopic morphology and imaging performance of MLA before and after flattening in the verification experiment.

[0048] Figure 12 To verify the focal spot image of the MLA after flattening and restoring the shape in the experiment DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0050] Example 1

[0051] This embodiment provides a shape-memory microlens array fabricated from a shape-memory polymer (SMP). This shape-memory microlens array exhibits exceptional plasticity, enabling it to be molded into various temporary configurations. Upon heating, it triggers a reconfiguration process, rapidly restoring its original optical performance. Because the focusing and imaging properties of this unique microlens array can be precisely controlled under specific conditions, it exhibits significant application potential in cutting-edge fields such as intelligent micro-optics and biomimetic devices, providing new insights and approaches for future optical system design.

[0052] Specifically, if Figure 1 As shown, the method for preparing the shape memory microlens array provided in this embodiment includes the following steps:

[0053] 1. Preparation of concave MLA template

[0054] (1) Quartz glass is processed by a femtosecond laser processing system to form pits on the quartz glass that match the size and spatial distribution of each lens unit in the shape memory microlens array.

[0055] Specifically, the femtosecond laser processing system employed in this embodiment uses a 1030nm femtosecond laser as its light source. During processing, the femtosecond laser processing system's pulse duration is set to 100fs, and the femtosecond laser beam is precisely focused on the quartz glass at a repetition rate of 100kHz. The laser beam forms an array of micropits on the glass surface, which serve as "seeds" for the subsequent etching process. Due to the unique chemical structure of the laser-modified area, it exhibits higher reactivity during the subsequent etching process.

[0056] (2) The quartz glass with the pit array processed is chemically etched using a 20% HF etching solution to obtain a concave MLA template with a smooth and uniform surface.

[0057] In this embodiment, the laser-modified area can be quickly removed under the action of 20% HF etching solution, thus forming a transition structure. As the etching time increases, the diameter and depth of the pit gradually increase, eventually evolving into a concave MLA. This process ensures the precise formation of the MLA, and by combining laser and chemical etching, it greatly improves processing efficiency and structural accuracy. After chemical etching, the quartz is cleaned and dried to obtain the desired concave MLA template.

[0058] 2. Preparation of Transparent SMP Materials

[0059] (3) The components for preparing the transparent shape memory material are mixed in a predetermined mass ratio and stirred thoroughly to ensure that the two are evenly mixed.

[0060] In this example, the transparent shape-memory material is made from epoxy resin E51 and epoxy resin curing agent D230, with a mass ratio of 3:1. Upon mixing, the epoxy resin and curing agent chemically react to form a cross-linked structure, which imparts the SMP with unique shape-memory properties.

[0061] (4) The mixture is subjected to vacuum treatment in an internal vacuum machine to obtain a transparent SMP material from which air and volatile substances are removed.

[0062] The SMP material, stirred and mixed in the previous step, contains air bubbles. This vacuuming step removes these bubbles, improving its transparency and appearance. This vacuuming effectively removes air and volatile substances from the SMP, making it more uniform and dense, and preventing structural defects in the resulting microlens array.

[0063] 3. Reconstructing Shape Memory Microlens Arrays

[0064] (5) The transparent SMP material is evenly coated on the concave MLA template.

[0065] In this embodiment, the SMP material must be ensured to fully fill and completely cover the MLA template. If necessary, vacuum treatment can be performed to ensure a sufficient fit between the SMP material and the MLA template. Furthermore, the shape memory microlens array reconstruction process in this embodiment should be performed in a dust-free environment to avoid contamination from particulate matter.

[0066] (6) The coated template was placed on a heating platform and heated at 65°C for 3 h to fully solidify the transparent SMP material to obtain a shape memory microlens array.

[0067] During the heating process of this step, the epoxy resin in the SMP further reacts chemically with the curing agent to form a stable cross-linked structure, thereby ensuring the adhesion and stability of the SMP on the MLA template.

[0068] (7) The cured shape memory microlens array and the MLA template are transferred to an infrared lamp at 85°C. Under the irradiation of infrared light, the surface of the SMP will heat up rapidly, becoming soft and easy to demold. After irradiation for 2-3 minutes, the softened shape memory microlens array is demolded.

[0069] This embodiment provides a method for processing an MLA template using a femtosecond laser as a processing medium in combination with a chemical etching method, and mass-producing a shape memory microlens array by a transfer method. The femtosecond laser used in this method has an extremely short pulse width and high pulse energy, which can realize the processing of the pit array in a very short time, and the heat effect generated during the operation is extremely small. The pulse width of the femtosecond laser is extremely short and the peak intensity is extremely high, which means that it can focus high energy density on a tiny action area in an instant. This high energy density injection causes a drastic change in the absorption and movement mode of electrons, thereby avoiding the problems of linear absorption, energy transfer and diffusion common in traditional laser processing.

[0070] The present invention uses a template processing method that combines femtosecond laser processing with chemical etching. This method not only improves processing accuracy and spatial resolution, but more importantly, it fundamentally changes the interaction mechanism between the laser and the material. This processing method has extremely high precision and applicability.

[0071] Example 2

[0072] Based on the optical properties of the shape memory microlens array provided in Example 1, such as controllable focusing, this embodiment further provides a multi-channel non-contact optical switch, such as Figure 2 As shown, it includes: a light control box, a laser, a lens array, a laser beam expander, a photosensitive array, a displacement mechanism, a flattening mechanism, a temperature control mechanism, and a controller.

[0073] The light control box includes a tubular darkroom with a square cross-section. A laser is located at one end of the darkroom in the light control box. The laser is used to emit laser light from one end of the darkroom to the other end; the laser light path emitted by the laser is along the axis of the darkroom. A lens array is installed in the middle of the darkroom in the light control box and is perpendicular to the extension direction of the darkroom. The lens array includes multiple lens units; the lens array adopts the shape memory microlens array as described in Example 1. The lens array is a flexible lens array and has the ability to recover its own deformation under specified temperature conditions.

[0074] The laser beam expander is located between the laser and the lens array, expanding the laser light into a collimated beam that covers the lens array. The photosensitive array is located on the other side of the darkroom, away from the laser. The photosensitive array contains a number of photosensitive units corresponding to the number of lens units in the lens array.

[0075] The displacement mechanism is used to move the photosensitive array along the extension direction of the light control box, thereby adjusting the relative distance between the photosensitive array and the lens array. The flattening mechanism, located within the light control box, is used to apply stress to the lens array, causing it to undergo plastic deformation. The temperature control mechanism regulates the temperature of the lens array to drive it back to its natural state after plastic deformation.

[0076] like Figure 3 As shown, the controller is electrically connected to the laser, the displacement mechanism, the flattening mechanism and the temperature control mechanism, and the controller is used to adjust the operating states of the laser, the displacement mechanism, the flattening mechanism and the temperature control mechanism.

[0077] The working principle of the multi-channel non-contact optical switch provided in this embodiment is as follows:

[0078] The displacement mechanism in the contactless light-operated switch can adjust the distance between the photosensitive array and the lens array. Under normal working conditions, the displacement mechanism will move the photosensitive array so that each photosensitive unit in the photosensitive array is located at the focal point of each lens unit in the lens array.

[0079] In the solution of this embodiment, each photosensitive unit in the photosensitive array acts as an independent optical switch, and a photodiode can be used in practical applications. The laser light emitted by the laser is expanded by a laser beam expander and then passes through a lens array. After the expanded laser light is focused by the lens array, it just reaches the activation threshold of the optical switch. In this state, if the lens array is in a natural state, the laser light focused by the lens array can reach the activation threshold of the photosensitive unit, and each optical switch is in the on state. However, when the lens array is flattened by a flattening mechanism, the lens array is in a deformed state. At this time, the lens array cannot focus the laser light at the photosensitive array; therefore, the laser light passing through the lens array cannot reach the activation threshold of the photosensitive unit, and the optical switch is in the off state.

[0080] In this embodiment, a flattening mechanism is used to squeeze both sides of the lens array along the optical axis, so that the lens array undergoes plastic deformation, thereby changing the optical characteristics of the lens array. Among them, when the flattening mechanism flattens the lens array, a certain operating space is usually required, and under normal conditions, the distance between the photosensitive array and the lens array is relatively close (equal to the focal length of the lens array). In order to achieve the extrusion deformation of the lens array, this embodiment installs the photosensitive unit on the displacement mechanism, and adjusts the distance between the photosensitive array and the lens array through the displacement mechanism. Specifically, when it is necessary to flatten the lens array, the photosensitive array is moved to the side away from the lens array through the displacement mechanism. When it is necessary to restore the normal optical performance of the lens system and turn on the optical switch, the photosensitive array is moved to the side close to the lens array.

[0081] For the lens array that has undergone plastic deformation, this embodiment uses a temperature control mechanism to restore its deformation, thereby restoring the optical performance of the lens array before flattening. Specifically, the temperature control mechanism in this embodiment adopts an infrared heater, which includes an infrared light source and a driving circuit. The driving circuit is used to adjust the luminous power of the infrared light source; the irradiation direction of the infrared light source points to the lens array. The infrared light generated by the infrared light source can directionally heat the lens array, thereby accurately adjusting the temperature of the lens array. Combined with the foregoing, it can be seen that the lens in this embodiment has a shape memory property of restoring its own deformation under preset temperature conditions. Therefore, in the solution of this embodiment, after the temperature of the lens array is accurately adjusted by the temperature control mechanism, the lens array can spontaneously restore to the state before flattening.

[0082] The flattening mechanism provided in this embodiment is as follows: Figure 4 As shown, the system comprises a first steering plate, a second steering plate, and a drive assembly. The first steering plate and the second steering plate are respectively located on either side of the lens array; the drive assembly is used to drive the first steering plate and the second steering plate to rotate synchronously and switch between the first state and the second state.

[0083] like Figure 4 As shown in the upper middle part, in the first state, the first steering plate and the second steering plate are rotated inwards to a state parallel to the lens array to clamp the lens array and cause the lens array to undergo plastic deformation. Figure 4 As shown in the lower middle part, in the second state, the first steering plate and the second steering plate are both rotated outward to a state perpendicular to the lens array, and thus moved away from the optical path of the laser.

[0084] In practical applications, we can use Figure 5 The magnetic control system shown as the drive component includes first and second electromagnetic units at corresponding positions on the first and second steering plates, and third and fourth electromagnetic units on the side of the light control box at positions corresponding to the deployed positions of the first and second steering plates.

[0085] like Figure 5 As shown in the upper middle section, when the first and second steering plates need to be aligned to compress the lens array between them, the magnetic poles of the adjacent surfaces of the first and second electromagnetic units are controlled to be opposite, while the magnetic poles of the adjacent surfaces of the first and third electromagnetic units, as well as the second and fourth electromagnetic units, are aligned. At this point, the magnetic force between the different electromagnetic units drives the first and second steering plates toward each other.

[0086] like Figure 5As shown in the lower middle section, when the first and second deflector plates need to move away from each other and release the central lens array, the adjacent surfaces of the first and second electromagnetic units are controlled to have the same magnetic poles, while the adjacent surfaces of the first and third electromagnetic units, as well as the second and fourth electromagnetic units, have opposite magnetic poles. At this point, the magnetic force between the different electromagnetic units drives the first and second deflector plates away from each other, and the deployed first and second deflector plates are adsorbed onto the side walls of the light control box.

[0087] In a more optimized solution of this embodiment, Figure 6 As shown, the multi-channel non-contact light-operated switch also includes a temperature sensor; the temperature sensor is located in a darkroom in the light-controlled box, the temperature sensor is electrically connected to the controller, and the controller measures the ambient temperature in the darkroom through the temperature sensor.

[0088] After monitoring the temperature in the darkroom through the temperature sensor, the controller can dynamically adjust the luminous power of the infrared light source according to the temperature detection results during the deformation recovery process of the lens array to achieve precise control of the temperature of the lens array.

[0089] Example 3

[0090] This embodiment provides a lens array state control mechanism for controlling the lens array's shape and thereby adjusting its optical performance. Specifically, the control mechanism comprises the flattening mechanism, temperature control mechanism, and controller of the multi-channel, contactless, light-controlled switch of Example 2. The flattening mechanism and temperature control mechanism are electrically connected to the controller. The flattening structure is used to compress the lens array, causing it to undergo plastic deformation. The temperature control mechanism is used to heat the lens array to restore its deformation.

[0091] Verification experiment

[0092] In order to verify the performance of the shape memory microlens array provided in Example 1 of the present invention, technicians trial-produced related products and tested the optical properties and deformation recovery performance of the products.

[0093] 1. Sample preparation

[0094] Technicians used the preparation method in Example 1 to manufacture a sample of shape memory microlens array (MLA). The lens size of the sample was 30 μm and the depth was 5 μm. The morphology of the microlens array was observed under a microscope. Figure 7 As shown in the figure, it can be seen that the surface of the microlens array after transfer is smooth and has good morphology.

[0095] 2. Focusing and imaging characteristics of MLA

[0096] In order to evaluate the imaging performance of MLA, an imaging system was constructed in this experiment. The core components of the imaging system include a stable light source, a mask with the letter "A" as a template as the imaging object, a 3D displacement platform, and a high-sensitivity CCD camera. In the system, MLA is fixed on a displacement stage to ensure the stability and accuracy of the imaging process. By adjusting the relative position between MLA and the platform, the CCD can capture a clear and sharp image at the focal plane. After a series of debugging and operations, the technicians successfully obtained the following Figure 8 The imaging results shown in Figure 3 show that the designed MLA exhibits excellent imaging capabilities and the resulting images are high in definition, fully verifying its excellent performance as an imaging element.

[0097] 3. Focal length measurement of MLA

[0098] Generally speaking, the geometric parameters that determine the microlens curvature radius R and focal length f can be calculated using the following formula:

[0099]

[0100] In the above formula, D and h are the diameter and height of the microlens respectively, and n is the refractive index of the SMP. Substituting the relevant values ​​into the formula, the theoretical focal length of the MLA is calculated to be 45.45μm. Then, the technicians tested the actual focal length of the MLA. Figure 9 The focus spot image of MLA is displayed. The results show that MLA has good focusing performance, the imaging results are consistent with the focusing characteristics, and the actual focal length of MLA is tested to be 45.7μm.

[0101] 4. Resolution of MLA

[0102] To estimate the resolution of the MLA, a specially designed resolution plate (USAF, 1951 standard, manufactured by Thorlabs) was used as the imaging target in this experiment. By precisely controlling the imaging conditions, technicians successfully captured images of the resolution plate and analyzed its imaging quality in detail. Figure 10 As shown in the figure, the fourth target element of the third group can be clearly distinguished in the image, so the corresponding resolution of MLA is 5.657 lp / mm.

[0103] 5. Reconfigurability of MLA

[0104] Due to the characteristics of SMP, the MLA prepared in this experiment is reconfigurable. In order to test this property, the technicians flattened the MLA with the help of a mechanical mold. The morphology after flattening is as follows: Figure 11 The imaging quality of the flattened MLA is shown in part (a). Figure 11As shown in part (b), the image is blurred because the shape of the MLA is destroyed after flattening.

[0105] After heat treatment, MLA can be restored to its original state. Its surface quality and forming characteristics after restoration are as follows: Figure 11 As shown in part (c), the imaging quality is as follows Figure 11 As shown in part (d).

[0106] Combine Figure 11 The data in the figure show that the shape memory MLA can be molded into any temporary structure, the reconfiguration process can be triggered under heating, and its optical properties can be restored. Finally, the focal length of the restored MLA was re-measured, and its focal spot image is shown in Figure 2. Figure 12 After multiple measurements and taking the average value, the focal length of the restored MLA is 45.175 μm, and the focal length of the initial MLA is 45.7 μm. The difference between the two is not much, indicating that the restored MLA has the same imaging performance. Therefore, the MLA prepared by this scheme has good reconfigurability.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-channel non-contact optical switch, characterized by: It includes: The light control box includes a tubular darkroom with a square cross section; a laser located at one end of the darkroom in the light control box; The laser is used to emit laser light from one end of the darkroom to the other end; the laser light path emitted by the laser is along the axis direction of the darkroom; A lens array is installed in the middle of the darkroom in the light control box and is perpendicular to the extension direction of the darkroom; the lens array includes a plurality of lens units; the lens array is a flexible lens array and has the ability to recover its own deformation under specified temperature conditions; a laser beam expander, located between the laser and the lens array, for expanding the laser light emitted by the laser into a collimated beam capable of covering the lens array; a photosensitive array located on the other side of the darkroom away from the laser, the photosensitive array comprising a number of photosensitive units corresponding to the number of lens units in the lens array, each photosensitive unit in the photosensitive array being located at a focal point of each lens unit in the lens array; A displacement mechanism, which is used to move the photosensitive array along the extension direction of the light control box, thereby adjusting the relative distance between the photosensitive array and the lens array; a flattening mechanism, located in the light control box, for applying stress to the lens array to cause plastic deformation of the lens array; a temperature control mechanism, configured to drive the lens array to return to a natural state after plastic deformation by regulating the temperature of the lens array; A controller is used to electrically connect the laser, the displacement mechanism, the flattening mechanism and the temperature control mechanism, and the controller is used to adjust the operating states of the laser, the displacement mechanism, the flattening mechanism and the temperature control mechanism.

2. The multi-channel non-contact optical switch according to claim 1, wherein: Each photosensitive unit in the photosensitive array acts as an independent optical switch. The laser emitted by the laser reaches the activation threshold of the optical switch after being expanded by the laser beam expander and focused by the lens array; so that when the lens array is in a deformed state, the optical switch is in a closed state; when the lens array is in a natural state, the optical switch is in an open state.

3. The multi-channel non-contact optical switch according to claim 1, wherein: The flattening mechanism includes a first steering plate, a second steering plate, and a drive assembly; the first steering plate and the second steering plate are respectively located on both sides of the lens array; the drive assembly is used to drive the first steering plate and the second steering plate to rotate synchronously and switch between the first state and the second state; In the first state, the first steering plate and the second steering plate are both rotated inwardly to a state parallel to the lens array, so as to clamp the lens array and cause the lens array to undergo plastic deformation; In the second state, the first deflection plate and the second deflection plate are both rotated outward to a state perpendicular to the lens array, thereby moving away from the optical path of the laser.

4. The multi-channel non-contact optical switch according to claim 1, wherein: The temperature control mechanism adopts an infrared heater, which includes an infrared light source and a driving circuit. The driving circuit is used to adjust the luminous power of the infrared light source; the irradiation direction of the infrared light source points to the lens array.

5. The multi-channel non-contact optical switch according to claim 1, wherein: It also includes a temperature sensor, which is located in the darkroom inside the light control box. The temperature sensor is electrically connected to the controller, and the controller measures the ambient temperature inside the darkroom through the temperature sensor.

6. The multi-channel non-contact optical switch according to claim 1, wherein: The flexible lens array is a shape memory microlens array, which is made of shape memory polymer SMP. The preparation method includes the following steps:

1. Preparation of concave MLA template (1) processing quartz glass by a femtosecond laser processing system to form pits on the quartz glass that match the size and spatial distribution of each lens unit in the shape memory microlens array; (2) Chemically etching the quartz glass with the pit array using 20% ​​HF etching solution to obtain a concave MLA template with a smooth and uniform surface; 2. Preparation of Transparent SMP Materials (3) Mixing the components for preparing the transparent shape memory material in a predetermined mass ratio and stirring them thoroughly to ensure that the two components are evenly mixed; (4) vacuuming the mixture in an internal vacuum machine to obtain a transparent SMP material from which air and volatile substances are removed; 3. Reconstructing Shape Memory Microlens Arrays (5) uniformly coating the transparent SMP material on the concave MLA template; (6) Place the coated template on a heating platform and heat it at 65°C for 3 h to fully solidify the transparent SMP material to obtain a shape memory microlens array; (7) Transfer the cured shape memory microlens array together with the MLA template to an infrared lamp at 85°C. After irradiation for 2-3 minutes, demold the softened shape memory microlens array.

7. The multi-channel non-contact optical switch according to claim 6, characterized in that: The light source of the femtosecond laser processing system is a 1030nm femtosecond laser. During the processing, the pulse duration is 100fs and the repetition frequency is 100kHz.

8. The multi-channel non-contact optical switch according to claim 6, wherein: The quartz after chemical etching in step (2) is cleaned and dried respectively to obtain the desired concave MLA template.

9. The multi-channel non-contact optical switch according to claim 6, characterized in that: In step (3), the components used to prepare the transparent shape memory material include epoxy resin E51 and epoxy resin curing agent D230, and the mass ratio of the two is 3:

1.

10. The multi-channel non-contact optical switch according to claim 9, characterized in that: In step three, the shape memory microlens array completes the reconstruction process in a dust-free environment.

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