A method for preparing a flexible smart liquid crystal polymer driver

Abstract

The application discloses a preparation method of a flexible intelligent liquid crystal polymer driver and relates to the technical field of liquid crystal polymer materials, and comprises the following steps: step one, configuring a liquid crystal mixture: one or more liquid crystal polymer monomers and a photoinitiator are mixed, and after being heated and melted, the mixture is uniformly shaken and stirred to obtain the liquid crystal mixture; step two, preparing a liquid crystal box: a liquid crystal box with a main body 90-degree twist orientation and one end structured orientation is prepared; step three, preparing a long-strip liquid crystal polymer film driver; and step four, driving and optically regulating the long-strip liquid crystal polymer film driver; the liquid crystal polymer driver prepared by the method has optical microstructures, can be bent and deformed under thermal field stimulation, and can also be regulated for light beam deflection to generate self-driven, self-feedback and self-sustaining dynamic optical function effects.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal polymer materials technology and optical control, specifically a method for the preparation and optical control of a flexible intelligent liquid crystal polymer actuator. Background Technology

[0002] Liquid crystal polymer actuators (LCPAs) are a type of cross-linked polymer formed by the cross-linking polymerization of liquid crystal molecules and non-cross-linked polymers under certain conditions. Liquid crystal polymers can be classified into three types based on their degree of cross-linking polymerization: liquid crystal polymers (LCPs), liquid crystal elastomers (LCELs), and liquid crystal networks (LCNs). Due to the presence of liquid crystal molecules, liquid crystal polymers are generally anisotropic and can undergo driven deformation responses under certain external stimuli, unlike isotropic polymer materials. Liquid crystal polymers can exhibit orientation effects under mechanical stretching or pre-orientation, and this orientation leads to driven deformation. When the external stimulus temperature increases, the sequence parameters change, causing the polymer to contract along the director direction and expand perpendicular to the director direction, resulting in significant macroscopic deformation. The polymer can return to its initial state when the external stimulus is removed. Under different design structures, different orientation patterns of the director result in different stimulus-response deformation effects of liquid crystal polymers, such as contraction and expansion, bending, twisting, and helicoid. Therefore, by designing different liquid crystal director structures, a wide range of flexible functional driven deformation applications can be obtained.

[0003] Currently, liquid crystals with in-plane and perpendicular orientation directional arrangements have been extensively studied, and these orientations are commonly used in the actuation design of liquid crystal polymers. The arrangement of liquid crystal molecules within the liquid crystal polymer material affects its macroscopic performance in response to external stimuli. Hybrid alignment nematic (one side perpendicularly oriented, the other in-plane oriented) liquid crystal polymers exhibit excellent bending deformation characteristics, while twist nematic (both sides are in-plane oriented, but in different directions) liquid crystal polymers demonstrate bending and helical deformation due to their deformation response. Both of these structures possess a natural advantage in bending deformation, spontaneously forming bending deformation simply by changing their own heating time parameters, unlike other materials that rely on multiple layers of isotropic nesting, where bending occurs due to the different thermal expansion coefficients of the materials. Furthermore, liquid crystals are widely used in optical applications and exhibit significant anisotropy; liquid crystal polymers also possess optical anisotropy.

[0004] Current applications of liquid crystal polymers' external field stimulus response characteristics are primarily in the fields of elastic and flexible deformation, biomimetic muscle tissue, and intelligent soft actuators. These external field stimuli are diverse, including heat, force, magnetism, light, humidity, electric fields, and pH values. These stimuli responses are all single-effect responses, i.e., "external field stimulus - driven deformation." For example, when external light is applied, the liquid crystal polymer, due to the photothermal effect of the added dyes, causes the illuminated area to heat up, resulting in deformation. If the anisotropic optical effects of liquid crystals can be combined with the polymer's driving characteristics, it could provide a new approach to the combined development of actuation and optical control in intelligent flexible actuators. That is, external stimuli are applied to the liquid crystal polymer, and its driving effect dynamically modulates the external field, resulting in a multi-effect control mechanism of "external field stimulus - driven deformation - modulated external field."

[0005] Based on this, if the macroscopic driving effect caused by external field stimulation can be applied to mechanical work or field control, it will provide a new platform and ideas for the development of flexible actuators. Summary of the Invention

[0006] Purpose of the invention: This invention addresses the problem that current applications of liquid crystal polymers are limited and their optical properties are not fully utilized. It provides a method for fabricating a flexible intelligent liquid crystal polymer actuator. The fabricated liquid crystal polymer actuator has an optical microstructure, enabling it to undergo bending deformation and self-driven oscillation motion under thermal stimulation, as well as dynamic beam bending and light field modulation under laser irradiation, thus achieving self-driven, self-feedback, and self-sustaining dynamic optical functions.

[0007] Technical solution: This invention discloses a method for preparing a flexible intelligent liquid crystal polymer actuator, comprising the following steps:

[0008] Step 1: Prepare the liquid crystal mixture;

[0009] One or more liquid crystal polymer monomers and a photoinitiator are mixed, heated to melt, and then shaken and stirred until homogeneous to obtain a liquid crystal mixture; the liquid crystal polymer monomer is an RM series liquid crystal monomer that can undergo polymerization reaction.

[0010] Step 2: Prepare the liquid crystal cell;

[0011] Step 1) Clean both glass pieces thoroughly, and spin-coat the light-controlled alignment agent solution within 2 hours after UVO irradiation;

[0012] Step 2) First, uniformly align the two glass pieces, that is, irradiate the two glass pieces with linearly polarized structured light with a wavelength of 350nm to 410nm for optically controlled orientation; then take one of the glass pieces and expose one end of it with DMD or expose it with a mask to obtain the optical microstructure pre-orientation effect.

[0013] Step 3) Use the two glass plates processed in Step 2) to prepare a liquid crystal cell with a cell thickness controlled between 100 μm and 150 μm, and prepare a liquid crystal cell with a main body 90° twist orientation and one end structured orientation.

[0014] Step 3: Prepare a strip-shaped liquid crystal polymer thin film actuator;

[0015] Step A: Heat the liquid crystal mixture prepared in Step 1 to a temperature higher than the clearing point temperature, then pour it into the liquid crystal cell prepared in Step 2, and cool it down to a temperature below the clearing point temperature. The temperature of the liquid crystal mixture after cooling should be controlled between 40℃ and 50℃.

[0016] Step B: Polymerize the liquid crystal cell under ultraviolet light at 365nm-410nm and intensity of 4-10mW / cm2 for 1 hour;

[0017] Step C: After polymerization, open the liquid crystal cell, take out the liquid crystal polymer film, and cut it into strips along or perpendicular to the orientation direction to obtain a strip-shaped liquid crystal polymer film driver.

[0018] Step 4: Drive and optically control the elongated liquid crystal polymer thin film actuator, using the following method;

[0019] The elongated liquid crystal polymer film driver is placed on a hot stage, where it undergoes bending deformation under thermal stimulation; when the region with optical microstructure is irradiated with a laser, it produces an optical modulation effect.

[0020] Furthermore, in step one, the liquid crystal polymer monomer is RM257, RM82, RM105 or RM23; the photoinitiator is Irgacure 651 or Irgacure 819.

[0021] Furthermore, the method for preparing the light-controlled alignment agent solution in step 1) is as follows: dissolve the light-controlled alignment agent SD1 in DMF to obtain the light-controlled alignment agent solution, wherein the mass fraction of SD1 in the light-controlled alignment agent solution is 0.3%.

[0022] Furthermore, in step 1), the spin coating operation is performed in two stages, specifically as follows:

[0023] In the first stage, the spin coating speed is set to 800 rpm, the duration is 5s to 10s, and the acceleration is 800 rpm / s.

[0024] In the second stage, the spin coating speed was set to 3000 rpm, the duration to 30 s, and the acceleration to 1000 rpm / s.

[0025] After spin coating, the product is dried and cured; the drying and curing conditions are heating at 100℃ for 10 minutes.

[0026] Furthermore, in step 2), different optical microstructures based on liquid crystal materials can be obtained by designing different exposure patterns. The optical microstructures include gratings, Q-plates, and Fresnel lens structures.

[0027] Furthermore, in step C, the length of the elongated liquid crystal polymer film driver is 25mm to 30mm, and the width is 1.5mm to 5mm.

[0028] Furthermore, in step four, the elongated liquid crystal polymer thin film driver is driven and optically controlled, specifically as follows:

[0029] 1) Place the elongated liquid crystal polymer film driver on the hot stage surface. The liquid crystal pointing direction on the upper surface of the elongated liquid crystal polymer film driver is parallel to its long side direction, and the liquid crystal pointing direction on the lower surface is parallel to its width direction.

[0030] When the temperature of the hot stage is controlled between 40℃ and 90℃, the elongated liquid crystal polymer actuator will bend when stimulated by the temperature rise, and the curvature of the liquid crystal polymer thin film actuator will continue to increase with the temperature rise; when the temperature of the hot stage is controlled at 92℃, the elongated liquid crystal polymer actuator will oscillate in a self-driven, self-feedback, and self-sustaining manner.

[0031] 2) When a laser is irradiated onto a liquid crystal polymer region with an optical microstructure, an optical modulation effect can occur. When the liquid crystal polymer thin film driver has an optical microstructure of a grating, the modulation of conical diffraction and the dynamic switching effect of optical diffraction occur. When the liquid crystal polymer thin film driver has an optical microstructure of a Q-plate, the generation of vector vortex light and the switching effect between vector vortex light and Gaussian light occur. When the liquid crystal polymer thin film driver has an optical microstructure of a Fresnel lens, the focusing and diverging light effects of Fresnel lenses occur.

[0032] Beneficial effects:

[0033] 1) This application makes full use of the anisotropy of liquid crystal. When used as a polymer, the liquid crystal produces a macroscopic deformation driving effect due to the symmetric broken director distribution characteristics. Furthermore, by utilizing its optical anisotropy to control the light field, deformation driving control and light field modulation can be achieved simultaneously.

[0034] 2) This application proposes to apply light-controlled orientation technology to liquid crystal polymers, which enriches their deformation characteristics. At the same time, a stable and controllable thermal stimulus response method is used to control the driving effect of liquid crystal polymers, thereby achieving stable control and programming effects.

[0035] 3) The light field control effect of this application is non-mechanical and does not require external mechanical control, thus facilitating practical applications.

[0036] 4) The materials of this invention are simple to prepare and have low cost; the optical microstructures are easy to prepare and have excellent light field control performance; optical microstructures based on liquid crystal materials with arbitrary structures can be obtained by designing exposure patterns.

[0037] 5) This invention realizes the design and fabrication of an optical component (liquid crystal polymer driver) with self-driving, self-feedback and self-maintaining dynamic optical functions. Attached Figure Description

[0038] Figure 1 A schematic diagram of the pointing vector of a cut-out strip of liquid crystal polymer film driver;

[0039] Figure 2 Temperature distribution diagram of a liquid crystal polymer driver with a length of 27 mm, a width of 2 mm, and a thickness of 105 μm at different hot stage temperatures;

[0040] Figure 3 To control the temperature to cycle between 40℃ and 85℃ at a rate of 30℃ / min, a schematic diagram showing the real-time rise and fall of the height of endpoint B with temperature changes.

[0041] Figure 4 A schematic diagram of the binary grating texture and the liquid crystal optical rotation effect of a liquid crystal polymer thin film driver (whose optical microstructure is a grating);

[0042] Figure 5 A schematic diagram of a liquid crystal polymer thin film driver (whose optical microstructure is a grating) changing the conical diffraction by temperature control;

[0043] Figure 6 This is a diagram showing the conical diffraction effect of a liquid crystal polymer thin-film driver (whose optical microstructure is a grating).

[0044] Figure 7 This refers to the deviation angle of each level of a liquid crystal polymer thin film driver (whose optical microstructure is a grating) under different incident angles during laser irradiation.

[0045] Figure 8 This is a schematic diagram illustrating the self-driving, self-feedback, and self-sustaining oscillation of a liquid crystal driver.

[0046] Figure 9 This is a schematic diagram illustrating the principle of a liquid crystal driver oscillating in a tumbler-like manner.

[0047] Figure 10 This is a schematic diagram of a self-driven, self-feedback, and self-sustaining liquid crystal polymer driver for a wobbling optical switch.

[0048] Figure 11 The diffraction effect diagram and the +1 order relative light intensity distribution diagram of the liquid crystal polymer driver during the self-driven oscillation process over multiple periods.

[0049] Figure 12 This is a schematic diagram illustrating the switching effect between vector vortex light and Gaussian light when a liquid crystal polymer thin film driver (whose optical microstructure is a Q-plate structure) is irradiated with laser.

[0050] Figure 13 This is a schematic diagram showing the convergence and divergence of light when a liquid crystal polymer thin-film driver (whose optical microstructure is a Fresnel lens structure) is irradiated with laser. Detailed Implementation

[0051] The technical solution of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments.

[0052] Example

[0053] Step 1: Prepare the liquid crystal mixture;

[0054] The liquid crystal polymer monomer and photoinitiator are mixed, heated to melt, and then shaken and stirred evenly to obtain a liquid crystal mixture.

[0055] The liquid crystal polymer monomer is a RM series liquid crystal monomer capable of undergoing polymerization; the liquid crystal polymer monomer includes RM257, RM82, RM105 and RM23, and one or two of them can be selected when preparing the liquid crystal mixture in step one; the photoinitiator is Irgacure 651 or Irgacure 819.

[0056] Among them, RM257 refers to 2-methyl-1,4-phenyl 4-(3-acryloyloxypropoxy)benzoic acid; RM82 refers to 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene; RM105 refers to 4-methoxyphenyl 4-[[6-[(1-oxo-2-propenyl)oxy]hexyl]oxy]benzoic acid; RM23 refers to 4-cyanophenyl 4-((6-(acryloyloxy)hexyl)oxy)benzoate; Irgacure 651 refers to benzoin dimethyl ether; and Irgacure 819 refers to phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0057] In this embodiment, the liquid crystal polymer monomers used are RM257 and RM105, and the photoinitiator is Irgacure 651. The liquid crystal polymer monomers RM257, RM105 and Irgacure 651 are mixed in a mass ratio of 38.5:60:1.5, heated to melt, and then shaken and stirred evenly to obtain a liquid crystal mixture.

[0058] Step 2: Prepare the liquid crystal cell;

[0059] Step 1) Clean the two 4*4cm pieces. 2 The glass was irradiated with UVO for 2 hours, and then a photo-aligning agent solution was spin-coated. The spin-coating operation was carried out in two stages, as follows:

[0060] In the first stage, the spin coating speed is set to 800 rpm, the duration is 5s to 10s, and the acceleration is 800 rpm / s.

[0061] In the second stage, the spin coating speed was set to 3000 rpm, the duration to 30 s, and the acceleration to 1000 rpm / s.

[0062] There is no interval between the first and second stages. After spin coating is completed, drying and curing are carried out. The drying and curing conditions are heating at 100°C for 10 minutes.

[0063] The method for preparing the light-controlled alignment agent solution is as follows: dissolve the light-controlled alignment agent SD1 in DMF to obtain the light-controlled alignment agent solution, wherein the mass fraction of SD1 in the light-controlled alignment agent solution is 0.3%; the light-controlled alignment agent SD1 refers to sodium 4,4′-bis(4-hydroxy-3-carboxy-phenylazo)benzidine-2,2′-disulphonate; DMF refers to dimethylformamide;

[0064] Step 2) First, the two glass pieces are uniformly oriented, that is, the two glass pieces are irradiated with linearly polarized structured light with a wavelength of 405nm for optically controlled orientation; then, one end of one of the glass pieces is exposed by DMD or by exposure with a mask to obtain the optical microstructure pre-orientation effect.

[0065] By designing different exposure patterns, optical microstructures based on liquid crystal materials with arbitrary structures can be obtained. These optical microstructures include gratings, Q-plates, and Fresnel lens structures.

[0066] Step 3) The two oriented glass pieces (after step 2) are used to prepare the liquid crystal cell: the cell thickness is controlled by a 100μm thick spacer strip (mylar film), and the liquid crystal cell is fixed with thermosetting adhesive. The actual thickness of the cell can be controlled to be 100μm~110μm, and a liquid crystal cell with a 90° twist orientation and a structured orientation at one end is prepared.

[0067] Step 3: Prepare a strip-shaped liquid crystal polymer thin film actuator;

[0068] Step A: Heat the liquid crystal mixture prepared in Step 1 to a temperature higher than the clearing point temperature, then pour it into the liquid crystal cell prepared in Step 2, and slowly cool it down to a temperature below the clearing point temperature. The temperature of the liquid crystal mixture after cooling is controlled at 40°C.

[0069] Step B: Expose the liquid crystal cell to ultraviolet light at 365nm with an intensity of 4–10 mW / cm. 2 Polymerize for 1 hour under the specified conditions.

[0070] Step C: After polymerization is complete, open the liquid crystal cell, remove the liquid crystal polymer film, and obtain an area greater than 1000 mm². 2 A liquid crystal polymer film is prepared and cut into strips along or perpendicular to the orientation direction to obtain a strip-shaped liquid crystal polymer film actuator; the length of the strip-shaped liquid crystal polymer film actuator is controlled at 27 mm, and the width is controlled at 2 mm to 2.5 mm.

[0071] The elongated liquid crystal polymer film actuator prepared in step three is a liquid crystal polymer with a 90° Twist structure, and the liquid crystal pointing direction on its upper surface and the liquid crystal pointing direction on its lower surface are perpendicular to each other. One end of the prepared elongated liquid crystal polymer film actuator has an optical microstructure.

[0072] Step 4: Drive and optically control the elongated liquid crystal polymer thin film actuator, as follows:

[0073] The elongated liquid crystal polymer thin film actuator prepared in step three undergoes bending deformation (driving characteristic) under thermal stimulation. When the region of the liquid crystal polymer thin film actuator with optical microstructure is irradiated with laser, optical modulation effect can occur. Specifically, when the liquid crystal polymer thin film actuator has an optical microstructure of grating, the modulation of conical diffraction and dynamic switching effect of optical diffraction can occur; when the liquid crystal polymer thin film actuator has an optical microstructure of Q-plate, the generation of vector vortex light and the switching effect between vector vortex light and Gaussian light can occur; when the liquid crystal polymer thin film actuator has an optical microstructure of Fresnel lens structure, the focusing and diverging light effects of Fresnel lens can occur.

[0074] To better understand the driving and optical control methods and effects of the elongated liquid crystal polymer thin film actuator, the following operations will be used as an explanation:

[0075] 1) Place the elongated liquid crystal polymer film driver on the hot stage surface; the liquid crystal pointing direction on the upper surface of the elongated liquid crystal polymer film driver is parallel to its long side direction, and the liquid crystal pointing direction on the lower surface is parallel to its width direction.

[0076] like Figure 1 As shown, Figure 1 This is a schematic diagram of the pointing vector of a cut-out 90° twisted liquid crystal polymer film driver, with length, width, and height L0, W0, and H0, respectively.

[0077] 2) When the temperature of the hot stage is controlled between 40℃ and 90℃, the liquid crystal polymer driver will bend when subjected to thermal stimulation due to temperature rise.

[0078] At the contact stage, the curvature of the liquid crystal polymer actuator continuously increases with temperature. The film on both arms away from the stage is flat, and the angle between the actuator and the horizontal plane of the stage can be controlled between 6.6° and 81.5°. During subsequent laser irradiation, when the laser is incident horizontally, the corresponding incident angle is controlled between 8.5° and 83.4°, and the incident angle changes with the curvature of the liquid crystal polymer. The range of the angle between the side arms and the horizontal plane of the stage, and the corresponding incident angle control, are as follows: Figure 2 , 3 As shown;

[0079] Figure 2 The figure shows the temperature distribution of a liquid crystal polymer driver with a length of 27 mm, a width of 2 mm, and a thickness of 105 μm at different hot stage temperatures (40℃~90℃). In the figure, A and B refer to the left and right ends of the liquid crystal polymer driver (in this embodiment, the two ends of the length direction of the strip-shaped liquid crystal polymer driver), L refers to the distance between the ends of A and B, and φ is the angle between the right arm and the horizontal plane (i.e., the angle between the right arm and the horizontal plane of the hot stage). The side arm refers to the part of the liquid crystal polymer driver that is heated and lifted up on both sides when heated. The right arm is the part of the liquid crystal polymer driver that is lifted up on the right side.

[0080] Figure 3 To control the temperature to cycle between 40℃ and 85℃ at a rate of 30℃ / min, a schematic diagram shows the real-time rise and fall of the height of endpoint B with temperature changes, where endpoint B corresponds to... Figure 2 Breakpoint B in the diagram; controlling the hot stage to continuously raise and lower the temperature at a rate of 30℃ / min can achieve a stable thermal control effect for driving liquid crystal polymers.

[0081] 3) Irradiating a liquid crystal polymer region with an optical microstructure with a laser can induce optical diffraction modulation. When the optical microstructure of the elongated liquid crystal polymer thin film actuator is a grating, the optical diffraction modulation that occurs during laser irradiation is as follows: Figures 4-7 As shown;

[0082] Figure 4 This diagram illustrates the binary grating texture of a liquid crystal polymer thin-film driver (whose optical microstructure is a grating) and the optical rotation effect of liquid crystal. The binary grating texture diagram is shown below. Figure 4 As shown in (a), the schematic diagram of the liquid crystal optical rotation effect is as follows: Figure 4 As shown in (b).

[0083] Figure 5 This is a schematic diagram of a liquid crystal polymer thin film driver (whose optical microstructure is a grating) that changes the conical diffraction by controlling temperature.

[0084] Figure 6 This is a cone diffraction effect diagram of a liquid crystal polymer thin film driver (whose optical microstructure is a grating), where θ refers to the position of a spot of a certain diffraction order and the angle between the central zero-order diffraction order spot and the horizontal line.

[0085] Figure 7 This represents the deviation angles of various orders of the diffraction beam from a liquid crystal polymer thin-film driver (whose optical microstructure is a grating) under different incident angles during laser irradiation. When the incident light irradiates the liquid crystal polymer grating at an incident angle of 70°, the deviation angle of its 24th order diffraction beam reaches 14.4°.

[0086] 4) Continue to raise the temperature of the hot stage to 92°C, causing the liquid crystal polymer driver to self-drive its oscillation, such as... Figure 8 As shown, the oscillation of the liquid crystal driver is similar to the self-driven, self-feedback, and self-sustaining oscillation of a roly-poly toy. Its dynamic principle is illustrated in the following diagram. Figure 9 As shown; because the temperature reaches the critical condition γ (specifically (L0-L) / L0, where L0 is the length of the film and L refers to the distance between endpoints A and B) is about 0.6, and because the center of gravity and the supporting force are not on the same straight line, the torque effect generated by their combined action enables the liquid crystal polymer driver to achieve a periodic self-sustaining oscillation effect.

[0087] By controlling the temperature of the hot stage at 92°C, the liquid crystal polymer driver undergoes self-driven, self-feedback, and self-sustaining oscillations, thereby driving the periodic changes in the position of the optical microstructure.

[0088] A schematic diagram of a self-driven, self-feedback, and self-sustaining liquid crystal polymer driver oscillating optical switch, controlling the laser height to remain constant, is shown below. Figure 10 As shown, whether periodic optical field modulation occurs after laser irradiation during the dynamic oscillation of the liquid crystal polymer driver depends on whether the laser irradiates the region of the optical microstructure. The diffraction effect diagram and the +1st order relative light intensity distribution diagram of the liquid crystal polymer driver during multi-cycle oscillation are shown below. Figure 11 As shown.

[0089] 5) When the optical microstructure of the prepared elongated liquid crystal polymer thin film actuator is a Q-plate, switching between vector vortex light and Gaussian light can occur during laser irradiation, and the vector light effect is excellent, such as... Figure 12 As shown, Figure 12 (a) Schematic diagram of the twist liquid crystal Q-plate; (b) Microscopic texture diagram; (c) Switching effect between Gaussian light and vector vortex light; (d) Detection effect of vector light. The switching between vector vortex light and Gaussian light is possible, and the vector light detection effect is excellent.

[0090] 6) When the optical microstructure of the prepared elongated liquid crystal polymer thin film actuator is a Fresnel lens structure, a Fresnel focusing effect can occur during laser irradiation, such as... Figure 13 As shown, Figure 13 (a) Twist Fresnel lens liquid crystal texture; (b) Switching between Gaussian beam and left-hand circularly polarized light convergence beam; (c) Effect of linearly polarized light output and divergence effect of right-hand circularly polarized light; For the left-hand circularly polarized component of the output light, there is a converging effect, and for the right-hand circularly polarized light, there is a diverging effect.

[0091] The Twist-structured liquid crystal polymer actuator of this invention not only possesses the anisotropy of liquid crystals, enabling manipulation of the optical field, but also exhibits macroscopic deformation capabilities under external field stimulation due to its asymmetric director distribution structure. When this type of liquid crystal polymer is designed and fabricated into a long strip shape with the directors on the upper and lower surfaces perpendicular or parallel to the length direction, it undergoes bending deformation under thermal field stimulation, strictly speaking, this deformation is similar to a saddle shape. Because its length is greater than its width, deformation in the width direction is suppressed, making it more closely resemble bending deformation. Designing and fabricating an optical microstructure at one end of the liquid crystal polymer actuator along its length direction allows it to achieve dynamic optical functions with self-driving, self-feedback, and self-sustaining capabilities.

[0092] Based on the concept of this invention, in addition to gratings, Q-plates, and Fresnel lens structures, more liquid crystal polymer thin film drivers with different optical microstructures can be designed to produce richer light field modulation effects, such as conical lenses, off-axis lenses, fork gratings, Dammann gratings, etc.

[0093] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for preparing a flexible intelligent liquid crystal polymer actuator, characterized in that, Includes the following steps: Step 1: Prepare the liquid crystal mixture; One or more liquid crystal polymer monomers and a photoinitiator are mixed, heated to melt, and then shaken and stirred until homogeneous to obtain a liquid crystal mixture; the liquid crystal polymer monomer is an RM series liquid crystal monomer that can undergo polymerization reaction. Step 2: Prepare the liquid crystal cell; Step 1) Clean both glass pieces thoroughly, and spin-coat the light-controlled alignment agent solution within 2 hours after UVO irradiation; Step 2) First, uniformly align the two glass pieces, that is, irradiate the two glass pieces with linearly polarized structured light with a wavelength of 350nm to 410nm for optically controlled orientation; then take one of the glass pieces and expose one end of it with DMD or expose it with a mask to obtain the optical microstructure pre-orientation effect. Step 3) Use the two glass plates processed in Step 2) to prepare a liquid crystal cell with a cell thickness controlled between 100 μm and 150 μm, and prepare a liquid crystal cell with a main body 90° twist orientation and one end structured orientation. Step 3: Prepare a strip-shaped liquid crystal polymer thin film actuator; Step A: Heat the liquid crystal mixture prepared in Step 1 to a temperature higher than the clearing point temperature, then pour it into the liquid crystal cell prepared in Step 2, and cool it down to a temperature below the clearing point temperature. The temperature of the liquid crystal mixture after cooling should be controlled between 40℃ and 50℃. Step B: Expose the liquid crystal cell to ultraviolet light at a wavelength of 365nm–410nm and an intensity of 4–10mW / cm. 2 Polymerize for 1 hour under the specified conditions; Step C: After polymerization, open the liquid crystal cell, take out the liquid crystal polymer film, and cut it into strips along or perpendicular to the orientation direction to obtain a strip-shaped liquid crystal polymer film driver. Step 4: Drive and optically control the elongated liquid crystal polymer thin film actuator, using the following method; The elongated liquid crystal polymer film driver is placed on a hot stage, and under the stimulation of a thermal field, it will bend and deform; when the region with optical microstructure is irradiated with a laser, it will produce an optical modulation effect. In step 2), different optical microstructures based on liquid crystal materials can be obtained by designing different exposure patterns. The optical microstructures include gratings, Q-plates, and Fresnel lens structures. In step four, the elongated liquid crystal polymer thin film driver is driven and optically controlled, specifically as follows: 1) Place the elongated liquid crystal polymer film driver on the hot stage surface. The liquid crystal pointing direction on the upper surface of the elongated liquid crystal polymer film driver is parallel to its long side direction, and the liquid crystal pointing direction on the lower surface is parallel to its width direction. When the temperature of the hot stage is controlled between 40℃ and 90℃, the elongated liquid crystal polymer actuator will bend when stimulated by the temperature rise, and the curvature of the liquid crystal polymer thin film actuator will continue to increase with the temperature rise; when the temperature of the hot stage is controlled at 92℃, the elongated liquid crystal polymer actuator will oscillate in a self-driven, self-feedback, and self-sustaining manner. 2) When a laser is irradiated onto a liquid crystal polymer region with an optical microstructure, an optical modulation effect can occur. When the liquid crystal polymer thin film driver has an optical microstructure of a grating, the modulation of conical diffraction and the dynamic switching effect of optical diffraction occur. When the liquid crystal polymer thin film driver has an optical microstructure of a Q-plate, the generation of vector vortex light and the switching effect between vector vortex light and Gaussian light occur. When the liquid crystal polymer thin film driver has an optical microstructure of a Fresnel lens, the focusing and diverging light effects of Fresnel lenses occur.

2. The method for preparing a flexible intelligent liquid crystal polymer actuator according to claim 1, characterized in that, In step one, the liquid crystal polymer monomer is RM257, RM82, RM105 or RM23; the photoinitiator is Irgacure651 or Irgacure819.

3. The method for preparing a flexible intelligent liquid crystal polymer actuator according to claim 1, characterized in that, The method for preparing the light-controlled alignment agent solution in step 1) is as follows: dissolve the light-controlled alignment agent SD1 in DMF to obtain the light-controlled alignment agent solution, wherein the mass fraction of SD1 in the light-controlled alignment agent solution is 0.3%.

4. The method for preparing a flexible intelligent liquid crystal polymer actuator according to claim 1, characterized in that, In step 1), the spin coating operation is performed in two stages, specifically as follows: In the first stage, the spin coating speed is set to 800 rpm, the duration is 5s to 10s, and the acceleration is 800 rpm / s. In the second stage, the spin coating speed was set to 3000 rpm, the duration to 30 s, and the acceleration to 1000 rpm / s. After spin coating, the product is dried and cured; the drying and curing conditions are heating at 100℃ for 10 minutes.

5. The method for preparing a flexible intelligent liquid crystal polymer actuator according to claim 1, characterized in that, In step C, the length of the elongated liquid crystal polymer film driver is 25mm to 30mm, and the width is 1.5mm to 5mm.

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