Preparation method of electrically controlled light modulation liquid crystal photoelectric detection film for on-site security

Abstract

The application provides a preparation method of an electrically-controlled light-adjusting liquid crystal photoelectric detection film for ground-oriented security, and belongs to the technical field of film preparation, and comprises the following steps: S1, liquid crystal light-adjusting film preparation; S2, photoelectric film preparation; S3, high-transmittance PET film preparation; S4, composite of the liquid crystal light-adjusting film and the high-transmittance PET film to obtain a first composite film; S5, composite of the photoelectric film and the first composite film to obtain a second composite film; S6, composite of the photoelectric film and the high-transmittance PET film on the side away from the first composite film to obtain an electrically-controlled light-adjusting liquid crystal photoelectric detection film; and S7, detection. The liquid crystal light-adjusting film and the photoelectric film are compounded to form the electrically-controlled light-adjusting liquid crystal photoelectric detection film, the transmittance of the electrically-controlled light-adjusting liquid crystal photoelectric detection film can be changed by using voltage, and the photoelectric detection demand under different transmittance environments can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film preparation, in particular to a preparation method of electrically controlled dimmable liquid crystal photoelectric detection thin film for ground proximity security. Background Art

[0002] A liquid crystal dimmable film is formed by injecting a liquid crystal / polymer mixed material between two transparent conductive films. When no electric field is applied, the liquid crystal dimmable film is in an opaque state; when alternating current is applied, liquid crystal molecules are arranged orderly, and the electro-induced dimmable film is converted from an opaque state to a transparent state. Rapid switching between on and off states can be achieved through the effect of the electric field. The basic working mechanism of a photodetector includes three processes: (1) photogenerated carriers are generated under illumination; (2) carriers diffuse or drift to form a current; (3) the photocurrent is amplified in an amplifier circuit and converted into a voltage signal. When the surface of the detector is irradiated with light, if the band gap of the material is smaller than the energy of incident light photons, that is Eg < hv, electrons in the valence band can transition to the conduction band to form a photocurrent. When light propagates in a semiconductor, the energy of the light wave gradually attenuates as it propagates, because photons are absorbed in the semiconductor. The most dominant absorption of photons by semiconductors is intrinsic absorption, which is divided into direct transition and indirect transition. Besides obtaining information such as the band gap of the semiconductor, testing the intrinsic absorption spectrum of the semiconductor can also be used to distinguish direct band gap semiconductors from indirect band gap semiconductors. Intrinsic absorption generally results in a relatively high absorption coefficient of the material, and semiconductors have a continuous absorption spectrum due to their energy band structure. It can be seen from the absorption spectrum that when intrinsic absorption starts, the absorption spectrum of the semiconductor has an obvious absorption edge. However, for silicon materials, since they are indirect band gap materials, the transition probability is lower compared to group III-V materials, so they only have a very small absorption coefficient, and meanwhile, under the irradiation of photons with the same energy, the light absorption depth in silicon materials is greater. The absorption edge of direct band gap materials is much steeper than that of indirect band gap materials.

[0003] The photoelectric thin film of a thin film photodetector directly changes electrical signals under illumination to detect whether an optical signal exists. However, existing photoelectric detection cannot adjust the light intensity irradiated on the photoelectric detection thin film according to actual use requirements, has low applicability, and cannot meet requirements under special environments. For this reason, the present invention provides a preparation method of an electrically controlled dimmable liquid crystal photoelectric detection thin film for ground proximity security. Summary of the Invention

[0004] The object of the present invention is to provide a preparation method of an electrically controlled dimmable liquid crystal photoelectric detection thin film for ground proximity security.

[0005] To solve the above technical problem, the object of the present invention is achieved as follows: A preparation method of an electrically controlled dimmable liquid crystal photoelectric detection thin film for ground proximity security, comprising the following steps: S1. Preparation of liquid crystal dimming film: A polymer-liquid crystal mixture is coated on an ITO conductive film, and then another ITO conductive film is laminated to form an ITO-polymer-liquid crystal mixture-ITO layer structure, which is then cured with ultraviolet light to obtain a liquid crystal dimming film. S2. Photoelectric film preparation: The photoelectric film includes a substrate, an electrode layer, and a photoelectric layer; the electrode layer is formed on the substrate first, and then the photoelectric layer is formed on the substrate, with the electrode layer in contact with the photoelectric layer; S3. Preparation of high-transmittance PET film: Copolyester chips, optical opening masterbatch and crystallizing nucleating agent are fed into an extruder, melt-extruded and biaxially stretched to obtain a high-transmittance PET film. S4. A first composite film is obtained by combining a liquid crystal dimming film with a high light transmittance PET film; adhesive is evenly coated on both sides, then two high light transmittance PET films are laminated, rolled and cured with ultraviolet light to obtain the first composite film. S5. The photoelectric film is combined with the first composite film to obtain the second composite film; the adhesive is evenly coated on one side of the first composite film, and then the photoelectric film is combined with the first composite film, rolled and cured by ultraviolet light to obtain the second composite film. S6. A high-transmittance PET film is laminated onto the side of the photoelectric film away from the first composite film to obtain an electronically controlled dimming liquid crystal photoelectric detection film; adhesive is uniformly coated on one side of the high-transmittance PET film, and then laminated with the side of the photoelectric film away from the first composite film. After rolling, it is cured with ultraviolet light to obtain an electronically controlled dimming liquid crystal photoelectric detection film. S7. Inspection; the inspection includes defect inspection and test inspection; The defect detection includes a first defect detection, a second defect detection, a third defect detection, and a fourth defect detection; The first defect detection is performed after the liquid crystal dimming film is prepared. An industrial camera is used to scan and identify the defects on the liquid crystal dimming film under the illumination of a light source. Then, the transmittance of the liquid crystal dimming film is detected by a transmittance detection mechanism before and after the transparency of the liquid crystal dimming film is changed by power. The defective areas and areas with unqualified transmittance are automatically marked. The second defect detection is performed after the high-transmittance PET film is produced. An industrial camera is used to scan and identify defects on the high-transmittance PET film online under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the high-transmittance PET film. The third defect detection is performed after the second composite film is prepared. An industrial camera is used to scan and identify defects on both sides of the second composite film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the liquid crystal dimming film before and after the transmittance is changed by energizing. The fourth defect detection is performed after the electronically controlled dimming liquid crystal photodetector film is prepared. An industrial camera is used to scan and identify defects on both sides of the electronically controlled dimming liquid crystal photodetector film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the electronically controlled dimming liquid crystal photodetector film before and after the transmittance changes after being powered on. The test, conducted after the preparation of the electrically controlled dimming liquid crystal photodetector film, includes the following steps: ① Without power, a variable intensity light source is placed on one side of the electrically controlled dimming liquid crystal photodetector film, and the film is irradiated with light of linearly varying intensity. The presence of an electrical signal in the photodetector film is monitored to determine whether the film's shielding performance meets the requirements. ② With power on, a stable light source is placed on one side of the electrically controlled dimming liquid crystal photodetector film to irradiate it. The transmittance is adjusted by changing the power supply voltage, and the photometric sensitivity of the film under different transmittance conditions is monitored. ③ With power on, maintaining the maximum transmittance of the liquid crystal dimming film, a variable intensity light source is placed on one side of the film, and the film is irradiated with light of linearly varying intensity. The sensitivity of the film in detecting light sources of different intensities is monitored.

[0006] Based on the above scheme and as a preferred embodiment, the liquid crystal dimming film is prepared as follows: In a Class 1,000,000 cleanroom environment, a chromium alloy coating roller is used to coat a polymer-liquid crystal mixture onto an ITO conductive film. Then, under a 300μm thick roller pressing operation, the two ITO conductive films and the polymer-liquid crystal mixture layer are bonded together to form a three-layer composite. During the curing process under ultraviolet irradiation, the intensity of the ultraviolet light is 60-70 mw / cm². 2 The curing temperature is 30±2℃.

[0007] Based on the above scheme and as a preferred embodiment of the above scheme, the photoelectric film is specifically prepared by: forming an electrode layer on a substrate by vacuum evaporation of conductive material electrodes; and growing a photoelectric layer on the substrate by molecular beam epitaxy.

[0008] Based on the above scheme and as a preferred scheme, the preparation of the high transmittance PET film is as follows: Step 1: Preparation of modified copolyester chips: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, heated, and vacuumed to react. After the reaction is completed, the pressure is reduced and the material is discharged, cooled, and granulated to make modified copolyester chips. Step 2: Preparation of optically openable masterbatch: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, barium sulfate and dispersant, heated and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion. Step 3: Preparation of crystallization nucleating agent: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, nano-kaolin and dispersant, heated and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion. Step 4: Copolyester chips, optically openable masterbatch and crystallization nucleating agent are fed into an extruder, melt-extruded and biaxially stretched to obtain a high-transmittance PET film.

[0009] Based on the above scheme and as a preferred embodiment of the above scheme, step S4 specifically refers to: uniform coating, which means using a chromium alloy coating roller in a 100,000-level cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 150 micrometers and 300 micrometers to composite two layers of high light transmittance PET film with liquid crystal dimming film.

[0010] Based on the above scheme and as a preferred embodiment of the above scheme, step S5 specifically refers to: uniform coating, which means using a chromium alloy coating roller in a 100,000-level cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 200 micrometers and 400 micrometers to composite the first composite film with the photoelectric film, wherein the photoelectric layer side of the photoelectric film is in contact with the first composite film.

[0011] Based on the above scheme and as a preferred embodiment of the above scheme, step S6 specifically refers to: uniform coating, which means using a chromium alloy coating roller in a 100,000-level dust-free environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 200 micrometers and 400 micrometers to laminate the second composite film with a high light transmittance PET film.

[0012] Based on the above scheme and as a preferred embodiment of the above scheme, a transparent hydrophobic and wear-resistant diamond-like film layer is provided on the surface of the high-transmittance PET film laminated on the side of the liquid crystal dimming film away from the photoelectric film.

[0013] The beneficial effects of this invention are: This invention combines a liquid crystal dimming film and a photoelectric film to form an electrically controlled dimming liquid crystal photoelectric detection film. The transmittance of the electrically controlled dimming liquid crystal photoelectric detection film can be changed by voltage, which can meet the photoelectric detection requirements under different transmittance environments. A high-transmittance PET film is placed between the liquid crystal dimming film and the photoelectric film, which not only makes the overall integrity of the electrically controlled dimming liquid crystal photoelectric detection film better, but also ensures that the transmittance of the film is not affected. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0015] Example 1: A method for preparing an electrically controlled dimming liquid crystal photodetector film for near-field security includes the following steps: S1. Preparation of liquid crystal dimming film: A polymer-liquid crystal mixture is coated on an ITO conductive film, and then another ITO conductive film is laminated to form an ITO-polymer-liquid crystal mixture-ITO layer structure, which is then cured with ultraviolet light to obtain a liquid crystal dimming film. S2. Photoelectric film preparation: The photoelectric film includes a substrate, an electrode layer, and a photoelectric layer; the electrode layer is formed on the substrate first, and then the photoelectric layer is formed on the substrate, with the electrode layer in contact with the photoelectric layer; S3. Preparation of high-transmittance PET film: Copolyester chips, optical opening masterbatch and crystallizing nucleating agent are fed into an extruder, melt-extruded and biaxially stretched to obtain a high-transmittance PET film. S4. A first composite film is obtained by combining a liquid crystal dimming film with a high light transmittance PET film; adhesive is evenly coated on both sides, then two high light transmittance PET films are laminated, rolled and cured with ultraviolet light to obtain the first composite film. S5. The photoelectric film is combined with the first composite film to obtain the second composite film; the adhesive is evenly coated on one side of the first composite film, and then the photoelectric film is combined with the first composite film, rolled and cured by ultraviolet light to obtain the second composite film. S6. A high-transmittance PET film is laminated onto the side of the photoelectric film away from the first composite film to obtain an electronically controlled dimming liquid crystal photoelectric detection film; adhesive is uniformly coated on one side of the high-transmittance PET film, and then laminated with the side of the photoelectric film away from the first composite film. After rolling, it is cured with ultraviolet light to obtain an electronically controlled dimming liquid crystal photoelectric detection film. S7. Inspection; the inspection includes defect inspection and test inspection; The defect detection includes a first defect detection, a second defect detection, a third defect detection, and a fourth defect detection; The first defect detection is performed after the liquid crystal dimming film is prepared. An industrial camera is used to scan and identify the defects on the liquid crystal dimming film under the illumination of a light source. Then, the transmittance of the liquid crystal dimming film is detected by a transmittance detection mechanism before and after the transparency of the liquid crystal dimming film is changed by power. The defective areas and areas with unqualified transmittance are automatically marked. The second defect detection is performed after the high-transmittance PET film is produced. An industrial camera is used to scan and identify defects on the high-transmittance PET film online under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the high-transmittance PET film. The third defect detection is performed after the second composite film is prepared. An industrial camera is used to scan and identify defects on both sides of the second composite film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the liquid crystal dimming film before and after the transmittance is changed by energizing. The fourth defect detection is performed after the electronically controlled dimming liquid crystal photodetector film is prepared. An industrial camera is used to scan and identify defects on both sides of the electronically controlled dimming liquid crystal photodetector film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the electronically controlled dimming liquid crystal photodetector film before and after the transmittance changes after being powered on. The test, conducted after the preparation of the electrically controlled dimming liquid crystal photodetector film, includes the following steps: ① Without power, a variable intensity light source is placed on one side of the electrically controlled dimming liquid crystal photodetector film, and the film is irradiated with light of linearly varying intensity. The film is monitored to see if it generates an electrical signal, thereby determining whether the film's blocking properties meet the requirements; ② With power on, a stable light source is placed on one side of the film to irradiate it; the transmittance is adjusted by changing the power supply voltage, and the photometric sensitivity of the film under different transmittance conditions is monitored; ③ With power on, maintaining the maximum transmittance of the liquid crystal dimming film, a variable intensity light source is placed on one side of the film, and the film is irradiated with light of linearly varying intensity. The sensitivity of the film to detect light sources of different intensities is monitored to ensure the film has good photodetector characteristics.

[0016] The preparation of the liquid crystal dimming film in step S1 specifically involves: in a Class 1,000,000 cleanroom environment, using a chromium alloy coating roller, coating a polymer-liquid crystal mixture onto an ITO conductive film; then, under roller pressing with a thickness of 300 μm, forming a three-layer composite of the two ITO conductive films and the polymer-liquid crystal mixture layer; the intensity of the ultraviolet light during the curing process under ultraviolet irradiation is 60-70 mw / cm. 2 The curing temperature is 30±2℃.

[0017] The photoelectric film preparation in step S2 specifically involves: forming an electrode layer on a substrate by vacuum evaporation of conductive material electrodes; and growing a photoelectric layer on the substrate using molecular beam epitaxy.

[0018] The preparation of the high transmittance PET film is as follows: Step 1: Preparation of modified copolyester chips: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, heated, and vacuumed to react. After the reaction is completed, the pressure is reduced and the material is discharged, cooled, and granulated to make modified copolyester chips. Step 2: Preparation of optically openable masterbatch: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, barium sulfate and dispersant, heated and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion. Step 3: Preparation of crystallization nucleating agent: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, nano-kaolin and dispersant, heated and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion. Step 4: Copolyester chips, optically openable masterbatch and crystallization nucleating agent are fed into an extruder, melt-extruded and biaxially stretched to obtain a high-transmittance PET film.

[0019] The specific step S4 is as follows: the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 150 micrometers and 300 micrometers to composite two layers of high light transmittance PET film with liquid crystal dimming film.

[0020] The specific step S5 is as follows: the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 200 micrometers and 400 micrometers to composite the first composite film with the photoelectric film, wherein the photoelectric layer side of the photoelectric film is in contact with the first composite film.

[0021] The specific step S6 is as follows: the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 200 micrometers and 400 micrometers to laminate the second composite film with a high light transmittance PET film.

[0022] Example 2: A method for preparing an electrically controlled dimming liquid crystal photodetector film for near-field security includes the following steps: S1. Preparation of Liquid Crystal Dimming Film: A polymer-liquid crystal mixture is coated onto an ITO conductive film, and then another ITO conductive film is laminated to form an ITO-polymer-liquid crystal mixture-ITO layer structure. The liquid crystal dimming film is then cured under ultraviolet light. Specifically, in a Class 1,000 cleanroom environment, a chromium alloy coating roller is used to coat the polymer-liquid crystal mixture onto the ITO conductive film. Then, under roller pressing with a thickness of 300 μm, the two ITO conductive film layers and the polymer-liquid crystal mixture layer are bonded together to form a three-layer composite. The intensity of the ultraviolet light during the curing process is 60-70 mw / cm². 2 The curing temperature is 30±2℃.

[0023] S2. Photoelectric Film Preparation: The photoelectric film comprises a substrate, an electrode layer, and a photoelectric layer. The electrode layer is first formed on the substrate, followed by the photoelectric layer, with the electrode layer in contact with the photoelectric layer. Specifically, a conductive material electrode is deposited on the substrate using vacuum evaporation to form the electrode layer; the photoelectric layer is then grown on the substrate using molecular beam epitaxy.

[0024] S3. Preparation of high-transmittance PET film: Copolyester chips, optical opening masterbatch and crystallizing nucleating agent are fed into an extruder, melt-extruded, and biaxially stretched to obtain a high-transmittance PET film. Preferably, the process includes the following steps: 1) Preparation of modified copolyester chips: The third monomer is mixed with ethylene glycol and a catalyst, then mixed with terephthalic acid, heated, and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure, cooled, and granulated to obtain modified copolyester chips; 2) Preparation of optically openable masterbatch: The third monomer is mixed with ethylene glycol and a catalyst, then mixed with terephthalic acid, barium sulfate, and a dispersant, heated, and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion; 3) Preparation of crystallizing nucleating agent: The third monomer is mixed with ethylene glycol and a catalyst, then mixed with terephthalic acid, nano-kaolin, and a dispersant, heated, and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion; 4) The copolyester chips, optically openable masterbatch, and crystallizing nucleating agent are fed into an extruder, melt-extruded, and biaxially stretched to obtain a high-transmittance PET film.

[0025] S4. A first composite film is obtained by laminating a liquid crystal dimming film with a high-transmittance PET film. Adhesive is uniformly coated on both sides, followed by lamination of two high-transmittance PET films. After rolling, the film is cured under ultraviolet light to obtain the first composite film. Specifically, the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment, controlling the coating thickness to 15-30 nanometers, and then performing rolling operations with a thickness between 150 and 300 micrometers to laminate the two layers of high-transmittance PET film with the liquid crystal dimming film.

[0026] S5. The photoelectric film and the first composite film are combined to obtain a second composite film; adhesive is uniformly coated on one side of the first composite film, and then the photoelectric film is laminated onto the first composite film. After rolling, it is cured with ultraviolet light to obtain the second composite film. Specifically, the uniform coating refers to using a chromium alloy adhesive roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then rolling with a thickness between 200 micrometers and 400 micrometers to laminate the first composite film and the photoelectric film, wherein the photoelectric layer side of the photoelectric film is in contact with the first composite film.

[0027] S6. A high-transmittance PET film is laminated onto the side of the photoelectric film away from the first composite film to obtain an electrically controlled dimming liquid crystal photodetector film; adhesive is uniformly coated on one side of the high-transmittance PET film, and then laminated with the side of the photoelectric film away from the first composite film. After rolling, it is cured with ultraviolet light to obtain the electrically controlled dimming liquid crystal photodetector film. Specifically, the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment, controlling the coating thickness to be 15-30 nanometers, and then rolling with a thickness between 200 micrometers and 400 micrometers to laminate the second composite film with the high-transmittance PET film.

[0028] S7. Inspection; The inspection includes defect inspection and test inspection. Defect inspection mainly detects whether there are defects in the composite film; test inspection mainly detects whether the optical performance of the film after lamination meets the requirements.

[0029] The defect detection includes a first defect detection, a second defect detection, a third defect detection, and a fourth defect detection; The first defect detection is performed after the liquid crystal dimming film is prepared. An industrial camera is used to scan and identify the defects on the liquid crystal dimming film under the illumination of a light source. Then, the transmittance of the liquid crystal dimming film is detected by a transmittance detection mechanism before and after the transparency of the liquid crystal dimming film is changed by power. The defective areas and areas with unqualified transmittance are automatically marked. The second defect detection is performed after the high-transmittance PET film is produced. An industrial camera is used to scan and identify defects on the high-transmittance PET film online under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the high-transmittance PET film. The third defect detection is performed after the second composite film is prepared. An industrial camera is used to scan and identify defects on both sides of the second composite film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the liquid crystal dimming film before and after the transmittance is changed by energizing. The fourth defect detection is performed after the electronically controlled dimming liquid crystal photodetector film is prepared. An industrial camera is used to scan and identify defects on both sides of the electronically controlled dimming liquid crystal photodetector film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the electronically controlled dimming liquid crystal photodetector film before and after the transmittance changes after being powered on. The test, conducted after the preparation of the electrically controlled dimming liquid crystal photodetector film, includes the following steps: ① Without power, a variable intensity light source is placed on one side of the electrically controlled dimming liquid crystal photodetector film, and the film is irradiated with light of linearly varying intensity. The film is monitored to see if it generates an electrical signal, thereby determining whether the film's blocking properties meet the requirements; ② With power on, a stable light source is placed on one side of the film to irradiate it; the transmittance is adjusted by changing the power supply voltage, and the photometric sensitivity of the film under different transmittance conditions is monitored; ③ With power on, maintaining the maximum transmittance of the liquid crystal dimming film, a variable intensity light source is placed on one side of the film, and the film is irradiated with light of linearly varying intensity. The sensitivity of the film to detect light sources of different intensities is monitored to ensure the film has good photodetector characteristics.

[0030] Furthermore, a transparent hydrophobic and wear-resistant diamond-like carbon (DLC) film layer is disposed on the surface of the high-transmittance PET film composited on the side of the liquid crystal dimming film away from the photoelectric film. The preparation method of the transparent hydrophobic and wear-resistant DLC film layer includes the following steps: (1) plasma etching treatment of the surface of the high-transmittance PET film; (2) using linear ion beam deposition, introducing carbon source gas methane, depositing a DLC film on the surface of the high-transmittance PET film after (1) treatment, and simultaneously introducing Ar gas during the deposition of the DLC film, so that film deposition and gas etching are carried out simultaneously; the water contact angle of the surface of the DLC film is greater than 90°, and it has excellent hydrophobic properties.

[0031] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-field security, characterized in that, Includes the following steps: S1. Preparation of liquid crystal dimming film: A polymer-liquid crystal mixture is coated on an ITO conductive film, and then another ITO conductive film is laminated to form an ITO-polymer-liquid crystal mixture-ITO layer structure, which is then cured with ultraviolet light to obtain a liquid crystal dimming film. S2. Photoelectric film preparation: The photoelectric film includes a substrate, an electrode layer, and a photoelectric layer; the electrode layer is formed on the substrate first, and then the photoelectric layer is formed on the substrate, with the electrode layer in contact with the photoelectric layer; S3. Preparation of high-transmittance PET film: Copolyester chips, optical opening masterbatch and crystallizing nucleating agent are fed into an extruder, melt-extruded and biaxially stretched to obtain a high-transmittance PET film. S4. A first composite film is obtained by combining a liquid crystal dimming film with a high light transmittance PET film; adhesive is evenly coated on both sides, then two high light transmittance PET films are laminated, rolled and cured with ultraviolet light to obtain the first composite film. S5. The photoelectric film is combined with the first composite film to obtain the second composite film; the adhesive is evenly coated on one side of the first composite film, and then the photoelectric film is combined with the first composite film, rolled and cured by ultraviolet light to obtain the second composite film. S6. A high-transmittance PET film is laminated onto the side of the photoelectric film away from the first composite film to obtain an electronically controlled dimming liquid crystal photoelectric detection film; adhesive is uniformly coated on one side of the high-transmittance PET film, and then laminated with the side of the photoelectric film away from the first composite film. After rolling, it is cured with ultraviolet light to obtain an electronically controlled dimming liquid crystal photoelectric detection film. S7. Inspection; the inspection includes defect inspection and test inspection; The defect detection includes a first defect detection, a second defect detection, a third defect detection, and a fourth defect detection; The first defect detection is performed after the liquid crystal dimming film is prepared. An industrial camera is used to scan and identify the defects on the liquid crystal dimming film under the illumination of a light source. Then, the transmittance of the liquid crystal dimming film is detected by a transmittance detection mechanism before and after the transparency of the liquid crystal dimming film is changed by power. The defective areas and areas with unqualified transmittance are automatically marked. The second defect detection is performed after the high-transmittance PET film is produced. An industrial camera is used to scan and identify defects on the high-transmittance PET film online under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the high-transmittance PET film. The third defect detection is performed after the second composite film is prepared. An industrial camera is used to scan and identify defects on both sides of the second composite film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the liquid crystal dimming film before and after the transmittance is changed by energizing. The fourth defect detection is performed after the electronically controlled dimming liquid crystal photodetector film is prepared. An industrial camera is used to scan and identify defects on both sides of the electronically controlled dimming liquid crystal photodetector film under light source illumination, and the defects are automatically marked. At the same time, a transmittance detection mechanism is used to detect the transmittance of the electronically controlled dimming liquid crystal photodetector film before and after the transmittance changes after being powered on. The test, conducted after the preparation of the electrically controlled dimming liquid crystal photodetector film, includes the following steps: ① Without power, a variable intensity light source is placed on one side of the electrically controlled dimming liquid crystal photodetector film, and the film is irradiated with light of linearly varying intensity. The presence of an electrical signal in the photodetector film is monitored to determine whether the film's shielding performance meets the requirements. ② With power on, a stable light source is placed on one side of the electrically controlled dimming liquid crystal photodetector film to irradiate it. The transmittance is adjusted by changing the power supply voltage, and the photometric sensitivity of the film under different transmittance conditions is monitored. ③ With power on, maintaining the maximum transmittance of the liquid crystal dimming film, a variable intensity light source is placed on one side of the film, and the film is irradiated with light of linearly varying intensity. The sensitivity of the film in detecting light sources of different intensities is monitored.

2. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-site security according to claim 1, characterized in that, The liquid crystal dimming film is prepared as follows: In a Class 1,000,000 cleanroom environment, a chromium alloy coating roller is used to coat a polymer-liquid crystal mixture onto an ITO conductive film. Then, under a 300μm thick roller pressing process, the two ITO conductive films and the polymer-liquid crystal mixture layer are bonded together to form a three-layer composite. During the curing process under ultraviolet irradiation, the intensity of the ultraviolet light is 60-70 mw / cm². 2 The curing temperature is 30±2℃.

3. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-site security according to claim 1, characterized in that, The photoelectric film is prepared by: forming an electrode layer on a substrate by vacuum evaporation of conductive material electrodes; and growing a photoelectric layer on the substrate by molecular beam epitaxy.

4. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-site security according to claim 1, characterized in that, The preparation of the high transmittance PET film is as follows: Step 1: Preparation of modified copolyester chips: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, heated, and vacuumed to react. After the reaction is completed, the pressure is reduced and the material is discharged, cooled, and granulated to make modified copolyester chips. Step 2: Preparation of optically openable masterbatch: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, barium sulfate and dispersant, heated and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion. Step 3: Preparation of crystallization nucleating agent: The third monomer is mixed with ethylene glycol and catalyst, then mixed with terephthalic acid, nano-kaolin and dispersant, heated and vacuumed for reaction. After the reaction is completed, the material is discharged under reduced pressure and granulated by twin-screw extrusion. Step 4: Copolyester chips, optically openable masterbatch and crystallization nucleating agent are fed into an extruder, melt-extruded and biaxially stretched to obtain a high-transmittance PET film.

5. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-site security according to claim 1, characterized in that, The specific step S4 is as follows: the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 150 micrometers and 300 micrometers to composite two layers of high light transmittance PET film with liquid crystal dimming film.

6. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-field security according to claim 1, characterized in that, The specific step S5 is as follows: the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing work with a thickness between 200 micrometers and 400 micrometers to composite the first composite film with the photoelectric film, wherein the photoelectric layer side of the photoelectric film is in contact with the first composite film.

7. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-site security according to claim 1, characterized in that, The specific step S6 is as follows: the uniform coating refers to using a chromium alloy coating roller in a Class 100,000 cleanroom environment to control the coating thickness to 15-30 nanometers, and then performing roller pressing with a thickness between 200 micrometers and 400 micrometers to laminate the second composite film with a high light transmittance PET film.

8. The method for preparing an electrically controlled dimming liquid crystal photodetector thin film for near-site security according to claim 1, characterized in that, A transparent, hydrophobic, and wear-resistant diamond-like film layer is disposed on the surface of the high-transmittance PET film on the side of the liquid crystal dimming film away from the photoelectric film.