Liquid crystal micro-optical module capable of flexibly and electrically adjusting polarization state in infrared mode and preparation method of liquid crystal micro-optical module

Abstract

According to the liquid crystal micro-optical module capable of flexibly and electrically adjusting the polarization state in the infrared mode and the preparation method of the liquid crystal micro-optical module, the liquid crystal box in the liquid crystal micro-optical module can conveniently change the orientation of liquid crystal molecules in the liquid crystal layer according to driving signals (such as voltage and current) of the controllable power supply; by combining the design that the molecular orientation of the first orientation layer and the molecular orientation of the second orientation layer are perpendicular to each other, intelligent polarization information driving control can be carried out on incident full-wave-band infrared light, and the polarization control device has various working modes of full polarization, polarization control and unpolarization, has extremely high structural, electrical and electro-optical parameter stability and is easy to control. Meanwhile, the manufactured liquid crystal micro-optical module is simple and small in structure, flexible in electric control, convenient to plug in and pull out in an optical path and easy to integrate and couple with various optical electrical mechanical structures, and the application range of full-band infrared polarization modulation is greatly expanded.

Description

Technical Field

[0001] The present invention relates to the field of infrared detection technology, and in particular to a liquid crystal micro-optical module with flexible infrared electrically adjustable polarization state and a preparation method thereof. Background Art

[0002] In a broad sense, light refers to electromagnetic waves across a wide spectrum, including ultraviolet, visible, infrared, and terahertz. In a narrower sense, light refers only to the visible wavelength range of 380 to 780 nanometers, visible to the human eye. With the continuous advancement of modern detection technology, imaging detection has expanded beyond the traditional visible light frequency domain to other invisible frequency domains. Infrared, with its distinct target radiation signature and 24 / 7 operation, has seen significant development in both military and civilian target detection. As an electromagnetic wave, infrared also possesses multiple dimensions of information, including amplitude, phase, polarization, spectrum, wavefront, and wave vector. Exploring any of these light wave parameters can provide an additional dimension of scene information beyond traditional two-dimensional imaging, thereby developing a new optoelectronic detection system. Polarization information primarily characterizes the polarization of the vibration vector during electromagnetic wave propagation and is often determined by the target's inherent characteristics.

[0003] The short-wave infrared band covers a wavelength range of 1-3 microns, the medium-wave infrared band covers a wavelength range of 3-5 microns, and the long-wave infrared band covers a wavelength range of 8-14 microns. These are all infrared window bands that are currently in urgent need of developing application scenarios. The development of infrared polarization information modulation devices targeting this infrared band range can inspire innovations in various detection technologies. In the past decade, liquid crystal-based optical devices have been widely used in various display fields. People have designed liquid crystal panels with various electrode patterns by leveraging the unique optoelectronic properties of liquid crystal materials. However, the development of liquid crystal devices suitable for the infrared band and how to enable flexible polarization control at a low cost remain issues that need to be considered in current research and development.

[0004] Therefore, there is an urgent need for a liquid crystal micro-optical module with flexible infrared electrically adjustable polarization state and a preparation method thereof to solve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a liquid crystal micro-optical module with flexible infrared electrically adjustable polarization state and a preparation method thereof, so as to solve the technical problem that the liquid crystal micro-optical module in the prior art is difficult to intelligently control the polarization information of the incident full-band infrared light.

[0006] To solve the above technical problems, the present invention provides an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state, comprising a liquid crystal cell, which comprises, in order along the propagation direction of the incident light wave, a first substrate, a first electrode layer, a first alignment layer, a liquid crystal layer, a second alignment layer, a second electrode layer, and a second substrate; The molecular alignment direction of the first alignment layer and the molecular alignment direction of the second alignment layer are perpendicular to each other.

[0007] Preferably, both the first substrate and the second substrate are capable of transmitting light in the 1-14 μm infrared band.

[0008] Preferably, the liquid crystal molecules of the liquid crystal layer are positive nematic liquid crystals; and the thickness of the liquid crystal layer is 10-20 μm.

[0009] Preferably, the materials of the first alignment layer and the second alignment layer both include polyimide; and the thickness of the first alignment layer and the second alignment layer both range from 100 to 200 μm.

[0010] Preferably, the materials of the first electrode layer and the second electrode layer both include ITO; and the thickness of the first electrode layer and the second electrode layer both range from 20 to 30 μm.

[0011] Preferably, the liquid crystal micro-optical module further comprises an optical anti-reflection film and a controllable power supply, wherein the optical anti-reflection film is arranged on a side of the first substrate away from the liquid crystal layer, and the controllable power supply is electrically connected to the liquid crystal box.

[0012] Accordingly, the present invention further provides a method for preparing an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state as described above, the method comprising the following steps: S10, sequentially forming a first electrode and a first alignment layer on one end surface of the first substrate, and simultaneously sequentially forming a second electrode and a second alignment layer on one end surface of the second substrate; S20, rubbing the first alignment layer along a first rubbing direction, and rubbing the second alignment layer along a second rubbing direction, wherein the first rubbing direction and the second rubbing direction intersect in a positive direction; S30, placing a side of the first substrate close to the first alignment layer and a side of the second substrate close to the second alignment layer opposite to each other, and performing a potting and packaging process with a packaging glue to obtain a liquid crystal cell; S40 , electrically connecting the controllable power supply to the liquid crystal box to obtain an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state.

[0013] Preferably, in the rubbing treatment in step S20, a flannel or a ruler is used to rub the first alignment layer or the second alignment layer, the rubbing force is 20 to 60 N, and the number of rubbing times is 10 to 30 times.

[0014] Preferably, the encapsulation glue selected for the die casting encapsulation process in step S30 includes epoxy resin and polyamide resin, and the mass ratio of epoxy resin to polyamide resin is 1:(1-3).

[0015] Preferably, in step S40: one end of the controllable power supply is electrically connected to the first electrode, and the other end of the controllable power supply is electrically connected to the second electrode.

[0016] The beneficial effects of the present invention are as follows: Unlike the prior art, the present invention provides a liquid crystal micro-optical module with flexible, electrically adjustable infrared polarization state and a method for preparing the same. The liquid crystal cell in the liquid crystal micro-optical module can conveniently change the orientation of the liquid crystal molecules in the liquid crystal layer by changing the drive signal (e.g., voltage or current) of a controllable power supply electrically connected to it. Combined with a design in which the molecular orientations of the first and second orientation layers are perpendicular to each other, this module can intelligently control the polarization information of incident infrared light across the entire wavelength band. The module has multiple operating modes, including full polarization, controlled polarization, and no polarization, and exhibits extremely high structural, electrical, and electro-optical parameter stability, making it easy to control. Furthermore, the resulting liquid crystal micro-optical module has a simple and compact structure, flexible electrical control, and is easily pluggable in the optical path. It can be easily integrated and coupled with various optical, electrical, and mechanical structures, greatly expanding the application range of full-band infrared polarization modulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the overall device structure of the infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state provided in Example 1 of the present invention; Figure 2 A flow chart of a method for preparing an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state provided in Example 1 of the present invention; Figure 3a Schematic diagram of the arrangement of the first alignment layer and adjacent liquid crystal molecules in the infrared flexible electrically tunable polarization state liquid crystal micro-optical module provided in Example 1 of the present invention; Figure 3b Schematic diagram of the arrangement of the second alignment layer and adjacent liquid crystal molecules in the infrared flexible electrically adjustable polarization state liquid crystal micro-optical module provided in Example 1 of the present invention; Figure 4 Schematic diagram of the working principle of the infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state provided in Example 1 of the present invention.

[0018] In the figure: 100 - liquid crystal micro-optical module; 11 - optical antireflection film; 12 - first substrate; 13 - first electrode layer; 14 - first alignment layer; 15 - liquid crystal layer; 150 - liquid crystal molecules; 16 - second alignment layer; 17 - second electrode layer; 18 - second substrate. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] The purpose of the present invention is to address the defects of the prior art and provide a liquid crystal micro-optical module 100 with flexible infrared electrically adjustable polarization state and a preparation method thereof, which can realize intelligent polarization information control of incident full-band infrared light.

[0021] The technical solution of the present invention will now be described with reference to specific embodiments.

[0022] Example 1: See also Figure 1 , Figure 1 Schematic diagram of the overall device structure of an infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state provided in Example 1 of the present invention; wherein the infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state includes a liquid crystal cell and a controllable power supply electrically connected to the liquid crystal cell. The liquid crystal micro-optical module 100 includes, in order along the propagation direction of the incident light wave, a first substrate 12, a first electrode layer 13, a first alignment layer 14, a liquid crystal layer 15, a second alignment layer 16, a second electrode layer 17, and a second substrate 18; The molecular alignment direction of the first alignment layer 14 and the molecular alignment direction of the second alignment layer 16 are perpendicular to each other.

[0023] Specifically, the liquid crystal micro-optical module 100 primarily utilizes the electro-optical properties of liquid crystals to operate. Before an external electric field is applied, the liquid crystal molecules 150 in the liquid crystal layer 15 have their initial arrangement state. When an external electric field is applied, the orientation of the liquid crystal molecules 150 changes. Because the arrangement direction of the liquid crystal molecules 150 is closely related to the polarization state of light, this change in orientation adjusts the polarization state of the target light wave passing through the liquid crystal micro-optical module 100. For example, changes in the degree of twisting, orientation angle, etc. of the liquid crystal molecules 150 can cause the polarization direction of the incident linearly polarized light to rotate by a certain angle, thereby changing the polarization state of the light.

[0024] In the first embodiment, the thickness of the liquid crystal micro-optical module 100 is in the millimeter order, which can greatly reduce the thickness of the liquid crystal micro-optical module 100 with flexible infrared electrically adjustable polarization state after overall integration.

[0025] In this first embodiment, both the first substrate 12 and the second substrate 18 are capable of transmitting light in the 1-14 μm infrared band with high transmittance. This provides a fundamental guarantee for the smooth entry and exit of target light waves into and out of the liquid crystal micro-optical module 100. They serve as the outer support structure of the entire assembly, supporting the various internal functional layers and ensuring the stability of the assembly structure, allowing the internal optical and electrical processes to proceed normally.

[0026] In this first embodiment, the liquid crystal molecules 150 of the liquid crystal layer 15 are positive nematic liquid crystals, which possess unique electro-optical properties. Under the influence of an external electric field, the liquid crystal molecules 150 can flexibly change their orientation, thereby affecting the polarization state of the target light wave passing through. This ability to change polarization state is the core of achieving different operating states of the infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state.

[0027] Specifically, in order to achieve the characteristics of small size and strong light control capability in the entire infrared band, the liquid crystal micro-optical module 100 uses infrared liquid crystal materials with excellent light control performance in this band. The thickness of the liquid crystal layer 15 is 10-20 μm, preferably 15 μm.

[0028] In this first embodiment, the molecular orientation of the first alignment layer 14 is perpendicular to that of the second alignment layer 16. This orthogonal arrangement plays a key role in guiding the liquid crystal molecules 150 in the liquid crystal layer 15. Based on the orientation of the two alignment layers, the liquid crystal molecules 150 exhibit a specific initial arrangement when no external voltage is applied. This typically results in a twisted structure, for example, where the liquid crystal molecules 150 are gradually twisted from top to bottom at a certain angle, laying the foundation for subsequent modulation of the polarization state of light through an electric field.

[0029] Specifically, the materials of the first alignment layer 14 and the second alignment layer 16 both include polyimide; the thickness of the first alignment layer 14 and the second alignment layer 16 both range from 100 to 200 μm, preferably 150 μm.

[0030] In the present embodiment 1, the first electrode layer 13 and the second electrode layer 17 do not need to be patterned, and they are electrically connected to the controllable power supply using a conductive tape with good conductive properties.

[0031] Specifically, in order to reduce the interference and transmittance of stray light during the use of the liquid crystal micro-optical module 100, indium tin oxide (ITO) is selected as the electrode material. It has good conductivity, the film layer is not easy to react with the solution used in the preparation of the liquid crystal box, and is easy to process; the thickness of the first electrode layer 13 and the second electrode layer 17 are both 20~30μm, preferably 25nm.

[0032] In this first embodiment, the liquid crystal micro-optical module 100 further includes an optical anti-reflection film 11, which is disposed on the side of the first substrate 12 away from the liquid crystal layer 15. The primary function of the optical anti-reflection film 11 is to reduce light reflection from the surface of the first substrate 12. When infrared light enters the liquid crystal micro-optical module 100 from the outside, it is reflected at the interface between the first substrate 12 and air, resulting in energy loss. The optical anti-reflection film 11 can offset the reflected light through the principle of interference, thereby increasing light transmittance.

[0033] The liquid crystal micro-optical module 100 provided in this embodiment 1 is based on the twisting effect of nematic liquid crystal, and integrates the twisted nematic liquid crystal layer 15 with the first substrate 12, the first electrode layer 13 and other structures into a typical multi-layer sandwich structure liquid crystal box. It does not require a complex electrode design, and adopts an orthogonal arrangement of the first orientation layer 14 and the second orientation layer 16 to form a longitudinally twisted arrangement of the nematic liquid crystal molecules 150 therein.

[0034] Specifically, when no external electric field is applied, since the twist pitch of the liquid crystal molecules 150 in the box is much larger than the infrared wavelength, the liquid crystal micro-optical module 100 can twist the polarization direction of the light wave whose polarization direction is parallel to the liquid crystal orientation on the incident surface by 90°, so that the polarization direction of the light wave is consistent with the molecular orientation of the exit surface of the liquid crystal layer 15 when it is emitted, thereby achieving the effect of adjusting the polarization state of the incident infrared light; when an external electric field greater than the threshold voltage of the liquid crystal cell is slowly applied, the liquid crystal molecules 150 in the liquid crystal layer 15 are arranged in the direction of the electric field and rearranged, at this time, the polarization direction of the incident infrared light will change with the change of the twist pitch of the rearranged liquid crystal molecules 150, and the polarization angle can be adjusted; when the external electric field applied exceeds the saturation voltage, except for the liquid crystal molecules 150 adjacent to the surface of the first electrode or the second electrode, all other liquid crystal molecules 150 in the liquid crystal cell will be arranged in the direction of the electric field, thereby being parallel to the first substrate 12 or the second substrate 18. At this time, the optical rotation function of the other liquid crystal molecules 150 in the liquid crystal cell disappears, and the full-band infrared light passing through the liquid crystal cell retains its original polarization characteristics.

[0035] See also Figure 2 , Figure 2 This is a flow chart of a method for preparing an infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state provided in Example 1 of the present invention. The method includes the following steps: S10 , a first electrode and a first alignment layer 14 are sequentially formed on one end surface of the first substrate 12 , and a second electrode and a second alignment layer 16 are sequentially formed on one end surface of the second substrate 18 .

[0036] Specifically, step S10 further includes: (1) Cleaning process 1: Using conventional ultrasonic cleaning equipment, the selected polished infrared glass substrate was placed in acetone, ethanol and deionized water solution for ultrasonic cleaning in turn, each time for 3 minutes. After cleaning, it was placed on a hot plate at 100°C for drying.

[0037] (2) Electrode layer preparation process-1: On one side end surface of two cleaned infrared glass substrates, a first electrode layer 13 and a second electrode layer 17 of 25nm indium tin oxide film are respectively deposited by electron beam evaporation coating process.

[0038] (3) Cleaning process-2: Clean the first substrate 12 coated with the first electrode layer 13 and the second substrate 18 coated with the second electrode layer 17, and repeat step (1).

[0039] (4) Orientation layer preparation process-1: On one end surface of the cleaned first substrate 12 covered with the first electrode layer 13 and one end surface of the second substrate 18 covered with the second electrode layer 17, a polyimide (PI) layer is coated using a coating machine as the first orientation layer 14 and the second orientation layer 16 in the liquid crystal box, respectively. The coating parameters are set to first rotate at a speed of 1200 rpm for 10 seconds and then at a speed of 3500 rpm for 30 seconds.

[0040] (5) Electrode layer preparation process-2: Place the first substrate 12 and the second substrate 18 coated with PI glue with the treated surface facing up on a hot plate set at 80°C and heat for 3 minutes. Then use a cotton swab dipped in ethanol solution to gently wipe off the PI at one end of the short side of the first substrate 12 and the second substrate 18 to expose the electrode layer under the PI at this position. Use a multimeter to test the resistance of the electrode position, determine the conductivity and adjust the operation.

[0041] (6) Orientation layer preparation process-2: After reserving the electrode position, adjust the temperature of the hot plate to 230°C for 30 minutes. After the first orientation layer 14 and the second orientation layer 16 are solidified, turn off the hot plate and wait for cooling.

[0042] S20 , rubbing the first alignment layer 14 along a first rubbing direction, and rubbing the second alignment layer 16 along a second rubbing direction, wherein the first rubbing direction and the second rubbing direction intersect in a positive direction.

[0043] Specifically, step S20 further includes: (7) Orientation layer preparation process-3: After the first substrate 12 and the second substrate 18 are cooled to room temperature, the first orientation layer 14 and the second orientation layer 16 need to be subjected to an orthogonal friction orientation operation, that is, a piece of velvet cloth for friction orientation and a ruler are selected, and the first orientation layer 14 and the second orientation layer 16 are rubbed downward along the ruler from top to bottom or from bottom to top in one direction; in a differentiated manner, the rectangular upper electrode is rubbed along the short side, and the lower electrode is rubbed along the long side.

[0044] Preferably, in the rubbing treatment of step S20 , a flannel is used to rub the first alignment layer 14 or the second alignment layer 16 along a ruler, with a rubbing force of 20 to 60 N and a rubbing frequency of 10 to 30 times.

[0045] (8) Cleaning process-3: Place the first substrate 12 and the second substrate 18 with the treated surfaces facing upward and separate them, and use an air blower to gently blow off the velvet debris that may be attached to the treated surfaces.

[0046] S30 , placing the side of the first substrate 12 close to the first alignment layer 14 and the side of the second substrate 18 close to the second alignment layer 16 opposite to each other and performing a die-casting and packaging process with a packaging glue to obtain a liquid crystal cell.

[0047] Specifically, step S30 further includes: (9) Microcavity fabrication process: A proper amount of epoxy resin and polyamide resin are mixed in a certain proportion, and 15 μm spacer microspheres are added to prepare a colloid with a certain viscosity. The first substrate 12 and the second substrate 18 are coated with the prepared colloid only on the short sides and arranged relatively staggered for gluing.

[0048] Preferably, the encapsulation glue selected for the die casting encapsulation process includes epoxy resin and polyamide resin, and the mass ratio of epoxy resin to polyamide resin is 1:(1-3), preferably 1:1.

[0049] (10) Pressing process: Clamp the short side of the liquid crystal cavity with a clamp and press it, and leave it for 24 hours to wait for the glue to completely solidify.

[0050] (11) Crystal filling process: Place the reserved unbonded long side upwards, dip the liquid crystal material from the needle tip and drip it from the top.

[0051] (12) Packaging process: Under the action of gravity and anchoring, the liquid crystal material will fill the cavity. The filling of liquid crystal is observed. After completion, the long sides of both sides are sealed with glue to make a liquid crystal box.

[0052] S40 , electrically connecting the controllable power supply to the liquid crystal box to obtain the infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state.

[0053] Specifically, step S40 further includes: One end of the controllable power supply is electrically connected to the first electrode, and the other end of the controllable power supply is electrically connected to the second electrode to obtain an infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state.

[0054] The specific preparation process of the infrared flexible electrically adjustable polarization state liquid crystal micro-optical module 100 proposed by the present invention is simpler than that of the traditional liquid crystal box. It does not require complex photolithography steps to prepare various patterned electrodes, avoiding a series of technical barriers caused by insufficient precision of the photolithography machine.

[0055] See also Figure 3a to Figure 3b , Figure 3a Schematic diagram of the arrangement of the first alignment layer 14 and adjacent liquid crystal molecules 150 in the infrared flexible electrically tunable polarization state liquid crystal micro-optical module 100 provided in Example 1 of the present invention; Figure 3bSchematic diagram of the arrangement of the second alignment layer 16 and adjacent liquid crystal molecules 150 in the infrared flexible electrically tunable polarization state liquid crystal micro-optical module 100 provided in Example 1 of the present invention.

[0056] Depend on Figure 3a as well as Figure 3b As can be seen, after rubbing the first and second alignment layers 14, 16 in orthogonal directions, a series of parallel grooves are formed. On the one hand, the nematic liquid crystal molecules 150 adjacent to the first or second alignment layer 14, 16 will form a certain initial orientation due to the grooves created by the first or second alignment layer 14, 16. Furthermore, the rubbed first or second alignment layer 14, 16 exerts a force on the adjacent liquid crystal molecules 150, minimizing their free energy in that direction, thereby deepening the orientation of the liquid crystal molecules 150 in that direction. The rubbing alignment technology employed is mature, does not require multiple equipment, and is simple to prepare.

[0057] The liquid crystal micro-optical module 100 fabricated in Example 1 of the present invention has a thickness of approximately 2 mm, and the liquid crystal layer 15 has a thickness of 15 μm, which does not affect the wave mechanics of infrared light across the entire target wavelength range. The indium tin oxide used as the electrode material has excellent conductivity and is not susceptible to reaction with the solutions used in the manufacturing process.

[0058] See also Figure 4 , Figure 4 This is a schematic diagram of the working principle of the liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state for infrared provided in Example 1 of the present invention. The working principle of the liquid crystal micro-optical module 100 is as follows: First, in the absence of an external electric field, the liquid crystal micro-optical module 100 is in a full polarization mode, capable of rotating the full-band infrared light whose incident polarization direction is parallel to the orientation direction of the incident surface by 90°, so that it is emitted in a polarization state orthogonal to the original polarization direction; when a root mean square voltage greater than the threshold voltage is slowly applied, the liquid crystal micro-optical module 100 is in a polarization adjustment mode, so that the polarization direction corresponding to the output voltage is infrared; when the applied voltage exceeds the saturation voltage, the liquid crystal micro-optical module 100 is in an unbiased mode, so that the target light wave whose original polarization direction is parallel to the orientation direction of the liquid crystal molecules 150 on the incident surface is emitted in the original polarization state, while filtering out stray light in other polarization directions.

[0059] Different from the prior art, the infrared liquid crystal micro-optical module 100 with flexible electrically adjustable polarization state provided by the present invention has the following advantages: First, when no external electric field is applied, the liquid crystal molecules 150 in the liquid crystal micro-optical module 100 are generally in an orthogonal twisted state, which can rotate the full-band infrared light whose incident polarization direction is parallel to the orientation direction of the incident surface by 90° through the liquid crystal layer 15, so that it is emitted in a polarization state orthogonal to the original polarization direction; previous related technologies based on twisted nematic liquid crystals focused on the visible light wave domain and did not expand the application spectrum. In this working state, a single-layer liquid crystal box structure can simultaneously achieve 90° optical rotation of 1-3 micron short-wave infrared light, 3-5 micron medium-wave infrared light, and 8-14 micron long-wave infrared light in the invisible spectrum.

[0060] Second, when an external electric field of a certain magnitude is applied to the first electrode layer 13 or the second electrode layer 17, the liquid crystal micro-optical module 100 can cause the incident full-band infrared light to emit polarization states in different directions under the action of electric fields of different intensities, thereby realizing flexible electrical adjustment of the polarization state and polarization angle of the target spectrum light wave.

[0061] Third, when the applied external electric field exceeds the saturation level, the liquid crystal micro-optical module 100 will cause the target light wave whose original polarization direction is parallel to the orientation direction of the liquid crystal molecules 150 on the incident surface to be emitted in the original polarization state, thereby filtering out stray light with other polarization directions.

[0062] In summary, the liquid crystal micro-optical electrically controlled polarization module provided by the present invention adopts a single-layer structure. It is manufactured based on the twisting effect of nematic liquid crystals. By constraining, intervening, or introducing an external electric field, it can intelligently control the polarization information of incident full-band infrared light. It has multiple operating modes: full polarization, controlled polarization, and no polarization. It has extremely high structural, electrical, and electro-optical parameter stability and is easy to control. At the same time, the resulting device has a simple and compact structure, flexible electrical control, easy insertion and removal in the optical path, and easy integration and coupling with various optical, electrical, and mechanical structures, which can greatly expand the application range of full-band infrared polarization modulation.

[0063] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For any details not described in individual embodiments, reference may be made to the description in other embodiments.

[0064] The above embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A liquid crystal micro-optical module with flexible infrared polarization adjustment, characterized in that: The liquid crystal cell comprises a first substrate, a first electrode layer, a first alignment layer, the liquid crystal layer, a second alignment layer, a second electrode layer, and a second substrate in sequence along the propagation direction of the incident light wave; The molecular alignment direction of the first alignment layer and the molecular alignment direction of the second alignment layer are perpendicular to each other.

2. The infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 1, characterized in that: Both the first substrate and the second substrate are capable of transmitting light in the 1-14 μm infrared band.

3. The infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 1, characterized in that: The liquid crystal molecules of the liquid crystal layer are positive nematic liquid crystals; and the thickness of the liquid crystal layer is 10-20 μm.

4. The infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 1, characterized in that: The materials of the first alignment layer and the second alignment layer both include polyimide; and the thicknesses of the first alignment layer and the second alignment layer both range from 100 to 200 μm.

5. The infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 1, characterized in that: The materials of the first electrode layer and the second electrode layer both include ITO; the thicknesses of the first electrode layer and the second electrode layer both are 20-30 μm.

6. The infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 1, characterized in that: The liquid crystal micro-optical module further includes an optical anti-reflection film and a controllable power supply. The optical anti-reflection film is arranged on a side of the first substrate away from the liquid crystal layer. The controllable power supply is electrically connected to the liquid crystal box.

7. A method for preparing an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: S10, sequentially forming the first electrode and the first alignment layer on one end surface of the first substrate, and simultaneously sequentially forming the second electrode and the second alignment layer on one end surface of the second substrate; S20, rubbing the first alignment layer along a first rubbing direction, and rubbing the second alignment layer along a second rubbing direction, wherein the first rubbing direction and the second rubbing direction intersect in a positive direction; S30, placing a side of the first substrate close to the first alignment layer and a side of the second substrate close to the second alignment layer opposite to each other, and performing a die-casting and packaging process using a packaging adhesive to obtain the liquid crystal cell; S40 , electrically connecting the controllable power supply to the liquid crystal box to obtain the liquid crystal micro-optical module with flexible electrically adjustable infrared polarization state.

8. The method for preparing an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 7, characterized in that: In the rubbing treatment of step S20 , a flannel is used to rub the first alignment layer or the second alignment layer along a ruler, with a rubbing force of 20 to 60 N and a rubbing frequency of 10 to 30 times.

9. The method for preparing an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 7, characterized in that: The encapsulation glue selected for the die casting encapsulation process in step S30 includes epoxy resin and polyamide resin, and the mass ratio of epoxy resin to polyamide resin is 1:(1-3).

10. The method for preparing an infrared liquid crystal micro-optical module with flexible electrically adjustable polarization state according to claim 7, characterized in that: In the step S40 , one end of the controllable power supply is electrically connected to the first electrode, and the other end of the controllable power supply is electrically connected to the second electrode.

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