Visible light polarization camera, preparation method and application thereof

Abstract

The present invention discloses a visible light polarization camera, comprising a camera lens, an electrically adjustable polarization TN liquid crystal device, an analyzer, an image sensor, and an image output unit. The electrically adjustable polarization TN liquid crystal device comprises a first electrode plate, a second electrode plate, a spacer group, and liquid crystal. The first end of the first electrode plate extends beyond the first end of the second electrode plate, and the second end of the second electrode plate extends beyond the second end of the first electrode plate. The first electrode plate comprises a first substrate, a first ITO conductive film, and a first orientation film, with a first orientation groove provided on the first orientation film. The second electrode plate comprises a second substrate, a second ITO conductive film, and a second orientation film, with a second orientation groove provided on the second orientation film. The second orientation groove is perpendicular to the first orientation groove. Liquid crystal is filled into the first and second orientation grooves. The visible light polarization camera of the present invention has a simple structure and is easy to implement. The electrically adjustable polarization TN liquid crystal device is directly inserted into the optical path of a conventional camera to achieve polarization selection, and the polarization effect is controlled by electrical adjustment.

Description

Technical Field

[0001] The present invention belongs to the field of optical imaging detection technology, and more specifically, relates to a visible light polarization camera, a preparation method thereof, and applications thereof. Background Art

[0002] Heavy fog and glare greatly restrict the imaging of sea surface targets on the camera. How to eliminate the influence of heavy fog and glare is an urgent problem to be solved in sea surface detection.

[0003] Currently, the most mature technology involves using near-infrared (NIR) filters on cameras for band-selective imaging, which improves transmittance and image contrast, but the effectiveness is limited. Polarization-based fog penetration is a hot topic of research. Since targets for optoelectronic observation are typically man-made objects such as ships and buildings, their reflection exhibits polarization selectivity, while atmospheric particles generally scatter uniformly. Leveraging this property, numerous institutions have conducted polarization-based fog penetration research, achieving some success. Water also reflects light with polarization selectivity, reflecting s-light and transmitting p-light, making polarization-based glare reduction effective. Implementing this method includes rotating polarizers, switching polarizers, and using detector micropolarizers. Rotating or switching polarizers is discontinuous in time and inefficient, and attaching micropolarizers to detectors is technically challenging. Therefore, a convenient and fast polarization-based method that is both temporally and spatially continuous, efficient, and cost-effective, while also accommodating detectors with different wavelengths, is urgently needed.

[0004] Currently, the focal plane array-based polarization imaging technology used in cameras is developing toward the integration of chip-level light field polarization measurement and imaging. Existing polarization imaging methods primarily utilize polarizing films to select and freeze the polarization state of the imaging light wave. These films are inserted into the imaging optical path or coupled with a photosensitive array to sense polarized light intensity. This makes it difficult to quickly switch between polarized and unbiased imaging, enabling real-time selection, freezing, adjustment, and transition of light polarization states. For example, currently commercially available metal wire grid polarization photosensitive chips can only capture horizontal, vertical, and ±45-degree polarization images, limiting their application.

[0005] In recent years, with the continued development of micro- and nano-encapsulation technologies for liquid crystal materials, research on wide-spectrum beam shaping, transformation, and control methods based on electrically controlled liquid crystals has garnered widespread attention. Electrically controlled liquid crystal micro-optics is evolving from its early days of light manipulation based on simple electric fields to a new generation of technologies where liquid crystal structures are driven and modulated by complex electric fields, enabling adjustable beams, energy states, polarization, and spectrum. This approach, which enhances imaging detection and recognition capabilities through light (or polarization) control based on electric field-driven spatial arrangement of liquid crystal molecules, has emerged and developed as a new high-performance imaging method. Achieving continuous polarization control of incident light while maintaining a simple liquid crystal device structure, low manufacturing cost, low power consumption, and ease of mass production has become a new research and development challenge in liquid crystal polarization devices. Furthermore, how to enable liquid crystal polarization devices to select and freeze an arbitrary polarization state and rapidly switch between biased and unbiased states remain hot topics in liquid crystal polarization device research, hindering their application in cameras. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvements in existing technologies, the present invention provides a visible light polarization camera, its preparation method, and its application. By adding an electrically adjustable polarization TN liquid crystal device to a conventional camera, the device in the optical path can be electrically adjusted to select and freeze any polarization state between 0° and 90°. Combined with a polarization analyzer, this camera achieves excellent polarization selection. Furthermore, the camera offers significant advantages such as electrically selectable, adjustable, and jumpable polarization capabilities, as well as fast response speed. This camera can be converted from a conventional camera to a polarization camera without the need for additional systems, thereby improving the utilization efficiency of existing cameras.

[0007] To achieve the above objectives, according to one aspect of the present invention, a visible light polarization camera is provided, comprising a camera lens, an electrically polarized TN liquid crystal device, an analyzer, an image sensor, and an image output unit arranged in sequence along an optical path, wherein the camera lens and the image output unit are both mounted on and exposed from a camera housing, the electrically polarized TN liquid crystal device and the analyzer are both mounted on an internal bracket, and the image sensor and the internal bracket are both mounted within the camera housing, characterized in that:

[0008] The electrically polarized TN liquid crystal device includes a first plate, a second plate, a spacer group, and liquid crystal, wherein the first plate and the second plate are parallel to each other and there is a distance between them, the spacer group is arranged between the first plate and the second plate, the liquid crystal is sealed and installed between the first plate and the second plate, the first end of the first plate extends beyond the first end of the second plate, and the second end of the second plate extends beyond the second end of the first plate, wherein the first end of the first plate and the second end of the first plate are arranged oppositely, and the first end of the second plate and the second end of the second plate are arranged oppositely, so that the first plate and the second plate are staggered; the first plate includes a plurality of electrodes arranged in sequence along a direction close to the second plate. A first substrate, a first ITO conductive film and a first orientation film, wherein a side of the first orientation film close to the second electrode plate is provided with a plurality of mutually parallel first orientation grooves, and a first end of the first electrode plate is partially exposed by removing a portion of the first orientation film; the second electrode plate comprises a second substrate, a second ITO conductive film and a second orientation film arranged in sequence along a direction close to the first electrode plate, a side of the second orientation film close to the first electrode plate is provided with a plurality of mutually parallel second orientation grooves, and a second end of the second electrode plate is partially exposed by removing a portion of the second orientation film, the second orientation grooves are perpendicular to the first orientation grooves, and the liquid crystal is filled in each of the first orientation grooves and each of the second orientation grooves.

[0009] Preferably, the image sensor is a CMOS image sensor.

[0010] Preferably, the first alignment film is made of polyimide or photoresist. If polyimide is used, the first alignment groove is formed by rubbing the first alignment film with a flannel. If photoresist is used, the first alignment groove is formed by irradiating the photoresist with light of a set wavelength and a set linear polarization state, and then developing and etching to remove the light.

[0011] The second orientation film is made of polyimide or photoresist. If polyimide is used, the second orientation groove is formed by rubbing the second orientation film with a flannel cloth; if photoresist is used, the photoresist is irradiated with light of a set wavelength and a set linear polarization state, and then the second orientation groove is formed by developing and etching.

[0012] Preferably, the distance between the first electrode plate and the second electrode plate is 10 μm to 30 μm;

[0013] The thickness of the first ITO conductive film is 100 nm to 200 nm, and the thickness of the first orientation film is 50 nm to 60 nm;

[0014] The thickness of the second ITO conductive film is 100 nm to 200 nm, and the thickness of the second alignment film is 50 nm to 60 nm.

[0015] Preferably, the first substrate is quartz glass or soda glass, and the second substrate is quartz glass or soda glass.

[0016] Preferably, a first wire is adhered to the portion of the first ITO conductive film exposed at the first end of the first electrode plate via conductive silver glue;

[0017] A second wire is adhered to a portion of the second ITO conductive film exposed at the second end of the second electrode plate via conductive silver glue.

[0018] Preferably, the calibration method of the electrically polarized TN liquid crystal device comprises the following steps:

[0019] 1) Building a calibration system: The calibration system includes a first polarizer, a second polarizer, and an optical power meter arranged in sequence along the propagation direction of light. Initially, the polarization directions of the first polarizer and the second polarizer are parallel. The optical power meter is used to detect the real-time received optical power.

[0020] 2) Rotating the second polarizer according to the set first step length until the polarization direction of the second polarizer is orthogonal to the polarization direction of the first polarizer, recording the optical power value of the optical power meter during this process, and obtaining a numerical mapping table and a fitting curve between the optical power value and the rotation angle of the second polarizer;

[0021] 3) placing an electrically tunable polarization TN liquid crystal device to be calibrated between a first polarizer and a second polarizer, with incident light sequentially passing through the first polarizer, the first electrode plate, the second electrode plate, and the second polarizer, and with the second orientation groove on the second orientation film of the electrically tunable polarization TN liquid crystal device being perpendicular to the polarization direction of the second polarizer; adjusting the voltage according to a set second step size to obtain optical power values ​​corresponding to each voltage, thereby obtaining a numerical mapping table between optical power values ​​and voltages;

[0022] 4) Substituting each optical power value obtained in step 3) into the fitting curve of the optical power value and the rotation angle obtained in step 2) to obtain the corresponding rotation angle, a numerical mapping table of the voltage and the rotation angle of the second polarizer can be obtained. The rotation angle of the second polarizer is used as the polarization angle of the electrically adjustable polarization TN liquid crystal device, and a numerical mapping table and fitting curve of the voltage and polarization angle of the electrically adjustable polarization TN liquid crystal device are obtained.

[0023] According to another aspect of the present invention, a method for preparing the visible light polarization camera is also provided, characterized in that it includes the following steps:

[0024] 1) Preparation of electrically polarized TN liquid crystal device, as follows:

[0025] 1.1) Preparation of the first electrode plate:

[0026] 1.1.1) Cleaning: Ultrasonic cleaning of the first substrate using acetone, isopropyl alcohol, and water in sequence, followed by drying;

[0027] 1.1.2) Coating: Electron beam evaporation is used to electroplate conductive metal ITO onto one surface of the cleaned first substrate to form a first ITO conductive film, which is then cleaned.

[0028] 1.1.3) Cleaning: Ultrasonic cleaning the first substrate coated with the first ITO conductive film using acetone, isopropyl alcohol, and water in sequence, and then drying;

[0029] 1.1.4) Slicing: Using a wafer slicer, cut the first substrate coated with the first ITO conductive film attached to the blue film or UV film using a blade. After slicing, clean the first substrate coated with the first ITO conductive film.

[0030] 1.1.5) Cleaning: Ultrasonic cleaning the first substrate coated with the first ITO conductive film using acetone, isopropyl alcohol, and water in sequence, followed by drying;

[0031] 1.1.6) Glue coating: Apply the first alignment film on the surface of the first ITO conductive film away from the first substrate using a glue roller;

[0032] 1.1.7) Exposing a portion of the first ITO conductive film: Transfer the first substrate coated with the first alignment film to a hot plate for preheating. Before the first alignment film solidifies, use a cotton swab dipped in alcohol to rub the first alignment film to expose a portion of the first ITO conductive film to facilitate voltage application.

[0033] 1.1.8) Curing: After preheating, increase the temperature of the hot plate to cure the first oriented film;

[0034] 1.1.9) Forming first alignment grooves: After the first substrate cools down, first alignment grooves are formed on the first alignment film to facilitate initial alignment of the liquid crystal molecules;

[0035] 1.2) Preparation of the second electrode plate:

[0036] 1.2.1) Taking a second substrate identical to the first substrate sliced ​​in step 1.4), coat one side of the second substrate with a second ITO conductive film, ultrasonically clean the second substrate coated with the second ITO conductive film using acetone, ethanol, and water, followed by drying;

[0037] 1.2.2) Glue coating: Use a glue spreader to apply a second alignment film on the surface of the second ITO conductive film away from the second substrate;

[0038] 1.2.3) Exposing the Second ITO Conductive Film: Transfer the second substrate coated with the second alignment film to a hot plate for preheating. Before the second alignment film solidifies, use a cotton swab dipped in alcohol to rub the second alignment film to expose a portion of the second ITO conductive film to facilitate voltage application.

[0039] 1.2.4) Curing: After preheating, increase the temperature of the hot plate to cure the second oriented film;

[0040] 1.2.5) Forming a second alignment groove: After the second substrate cools down, a second alignment groove is formed on the second alignment film to facilitate the initial alignment of the liquid crystal molecules;

[0041] 1.3) Assembly:

[0042] 1.3.1) Fixing the First and Second Plates: Arrange the first orientation film of the first plate and the second orientation film of the second plate opposite each other and staggered to leave space for the leads, and make the first orientation groove and the second orientation groove perpendicular to each other. Use glass microspheres as spacers between the first and second orientation films to form a cavity between the first and second plates. Adhere the first and second plates together by mixing AB glue with the spacers.

[0043] 1.3.2) Encapsulation: Liquid crystal is filled into the cavity between the first and second plates by siphoning, and the cavity is sealed with encapsulation material;

[0044] 1.3.3) Leads: Use conductive silver glue to adhere a wire to the portion of the first ITO conductive film exposed at the first end of the first electrode plate. Then, use conductive silver glue to adhere a wire to the portion of the second ITO conductive film exposed at the second end of the second electrode plate. Heat and dry the conductive silver glue.

[0045] 2) The electrically polarized TN liquid crystal device and the analyzer are respectively mounted on the internal bracket, the internal bracket and the image sensor are respectively mounted in the camera housing, and the camera lens and the image output unit are respectively mounted on the camera housing, ensuring that the camera lens, the electrically polarized TN liquid crystal device, the analyzer, the image sensor and the image output unit are arranged in sequence along the optical path.

[0046] According to another aspect of the present invention, an application of the visible light polarization camera is also provided, characterized in that the voltage is continuously increased between the first ITO conductive film of the first electrode plate and the second ITO conductive film of the second electrode plate through a power supply, so that the long axis of the liquid crystal molecules is arranged along the electric field lines under the action of the external electric field, and the liquid crystal molecules are gradually deflected from the 90° twist angle in the initial state to the long axis of the liquid crystal molecules being perpendicular to the first substrate, thereby achieving continuous adjustment of the polarization angle of the incident light.

[0047] Preferably, the power supply is an AC power supply, the signal type is a sine wave or a bipolar square wave with a duty cycle of 50%, the voltage changes linearly and continuously in the range of 0.01V to 20.00V, and the signal frequency is in the range of 1KHz to 5KHz.

[0048] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0049] 1) When the voltage value between the first ITO conductive film of the first electrode plate and the second ITO conductive film of the second electrode plate is continuously changed, the spatial electric field changes from weak to strong, and the direction of the long axis of the liquid crystal molecules changes continuously, from the initial state with a twist angle of 90° and parallel to the first substrate, to the long axis of the liquid crystal molecules being deflected along the electric field line to being perpendicular to the first substrate, causing the overall equivalent twist angle to change continuously. The incident polarized light can be twisted from 90° in the initial state without power supply to 0° in the power supply state, thereby achieving the effect of continuous adjustment of polarized light. Compared with the prior art, the visible light polarization camera of the present invention has a simple structure and is easy to implement. No other auxiliary systems are required. The electrically adjustable polarization TN liquid crystal device can be directly inserted into the optical path of a traditional camera to realize the polarization selection function, and the polarization effect can be controlled by electrical adjustment.

[0050] 2) The electrically polarized TN liquid crystal device can quickly solidify and select a specific angle of polarization state by adjusting the voltage amplitude. It can not only realize continuous selection of polarization state by powering on, but also realize jump selection of polarization state by discontinuous powering on, thus accelerating the efficiency of polarization imaging selection.

[0051] 3) The electronic adjustment can reverse the polarization direction of the incident light, which can be applied to practical scenarios such as eliminating strong glare on the water surface and defogging in bad weather in the field of imaging detection, thereby improving the contrast of effective signal detection.

[0052] 4) The electrically polarized TN liquid crystal device of the present invention can be easily matched with traditional cameras to achieve polarization imaging. Compared with traditional wire-grid polarization cameras, it does not require loss of camera spatial resolution, improves target detection efficiency, and can continuously capture images at multiple polarization angles, rather than the traditional 0°, 45°, and 90° polarization angles, which has great practical application significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is an exploded schematic diagram of the visible light polarization camera of the present invention;

[0054] Figure 2 is a cross-sectional schematic diagram of the electrically polarized TN liquid crystal device of the present invention;

[0055] Figure 3 This is a schematic diagram of the plane orientation angle of the first orientation film of the electrically polarized TN liquid crystal device of the present invention;

[0056] Figure 4 Schematic diagram of the plane orientation angle of the second orientation film of the electrically polarized TN liquid crystal device of the present invention;

[0057] Figure 5a to Figure 5c This is a schematic diagram of the equivalent twisting of liquid crystal molecules when different voltages are applied to the electrically polarized TN liquid crystal device of the present invention;

[0058] Figure 6a is a schematic diagram of the calibration system of the present invention;

[0059] Figure 6b It is a schematic diagram of placing an electrically polarized TN liquid crystal device in the calibration system of the present invention. DETAILED DESCRIPTION

[0060] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0061] Referring to the accompanying drawings, a visible light polarization camera includes a camera lens 12, an electrically tunable polarization TN liquid crystal assembly 3 (TN, short for twisted nematic), an analyzer 4, an image sensor 53, and an image output unit 51, arranged sequentially along the optical path. The camera lens 12 and the image output unit 51 are mounted on and exposed from a camera housing. The electrically tunable polarization TN liquid crystal assembly 3 and the analyzer 4 are mounted on an internal bracket 2. The image sensor 53 and the internal bracket 2 are mounted within the camera housing. The image sensor 53 is preferably a CMOS image sensor 53. The camera housing includes a lens connection housing 11 and a detection system connection housing 52. The camera lens 12 is mounted on the lens connection housing 11, and the detection system connection housing 52 connects the internal bracket 2, the image sensor 53, and the image output unit 51. The camera lens 12 and the lens connection housing 11 together constitute a lens system 1. The detection system connection housing 52, the image output unit 51, and the image sensor 53 together constitute a detection system 5.

[0062] The visible light polarization camera of the present invention requires certain physical modifications to conventional cameras. Because a power-required electrically tunable polarization TN liquid crystal module 3 must be inserted into the conventional camera structure, AC power must be supplied to the inserted TN liquid crystal module 3. This requires that the positive and negative leads of the TN liquid crystal module 3 be connected after insertion to provide power. Therefore, certain physical modifications to the conventional camera components are necessary based on practical needs. Compared to a direct camera replacement, the conventional camera's lens system and CMOS system can remain operational, ensuring system compatibility with conventional cameras.

[0063] A traditional camera has been modified, retaining all key components, such as the lens and imaging system. An electrically polarized TN liquid crystal assembly 3 is inserted between the lens and the imaging CMOS. The image sensor 53 of the present invention preferably utilizes a CMOS photosensitive chip (a physical photosensitive matrix composed of individual pixels, each corresponding to a pixel in the final image). In a real-world camera, the initial data obtained by the CMOS photosensitive chip undergoes certain processing and is then output in some manner, resulting in the user receiving the final image. For example, if a Hikvision industrial camera is used, when the user presses the shutter (photo button) in the host computer software, the industrial camera begins capturing images. During this process, the CMOS photosensitive chip first transmits the photosensitive data to the camera system for noise processing, generating an image. Finally, the image is transmitted to the user's end (e.g., a computer) via the image output unit 52, where the image is transmitted via the GigE protocol (network interface). The image output unit 52 delivers the final processed image to the user via some protocol. In contrast, traditional cameras store the image directly to the camera's internal memory card after taking a photo, which the user then copies to the memory card. The camera of the present invention has a direct interface to automatically transmit pictures back to the user, such as using a USB protocol.

[0064] Since there is an electrically adjustable polarization TN liquid crystal component 3 before the polarizer, the electrically adjustable polarization TN liquid crystal component 3 is equivalent to a polarization rotator. That is, the polarization direction of the incident polarized light will be deflected by a certain angle after passing through the electrically adjustable polarization TN liquid crystal component 3. At this time, the polarization analyzer 4 is needed to analyze the polarization to see the effect. Different voltages will cause the polarization angle of the electrically adjustable polarization TN liquid crystal component 3 to be different. Only by adding a polarization analyzer between the electrically adjustable polarization TN liquid crystal component 3 and the image sensor can the difference be seen. Otherwise, no matter how many degrees the electrically adjustable polarization TN liquid crystal component 3 is rotated, the imaging effect for the camera CMOS will be the same.

[0065] The electrically polarized TN liquid crystal device 3 includes a first plate 31, a second plate 32, a spacer group 33, and liquid crystal 34. The first plate 31 and the second plate 32 are parallel to each other with a gap between them. The spacer group 33 is disposed between the first plate 31 and the second plate 32. The liquid crystal 34 is sealed between the first plate 31 and the second plate 32. The spacer group 33 surrounds the liquid crystal 34, which is a nematic liquid crystal. The liquid crystal 34 can be sealed using a potting compound.

[0066] The first end of the first electrode plate 31 extends beyond the first end of the second electrode plate 32, and the second end of the second electrode plate 32 extends beyond the second end of the first electrode plate 31. The first end of the first electrode plate 31 and the second end of the first electrode plate 31 are arranged opposite to each other, and the first end of the second electrode plate 32 and the second end of the second electrode plate 32 are arranged opposite to each other, so that the first electrode plate 31 and the second electrode plate 32 are staggered.

[0067] The first electrode 31 includes a first substrate 311, a first ITO conductive film 312, and a first orientation film 313 arranged in sequence along the direction close to the second electrode 32. The first substrate 311 is quartz glass or soda glass. The first orientation film 313 is provided with a plurality of mutually parallel first orientation grooves on a side close to the second electrode 32. The first end of the first electrode 31 is exposed by removing part of the first orientation film 313 to expose part of the first ITO conductive film 312. Preferably, the edge area 3121 of the first ITO conductive film 312 is exposed as a lead area. The first orientation film 313 is made of polyimide or photoresist. The first orientation film 313 can be a traditional friction-oriented PI (Polymide) film or a photoresist based on light-controlled orientation. If polyimide is used, the first orientation groove is formed by rubbing the first orientation film 313 with a flannel cloth. Figure 2 The extension direction 3131 of the first directional groove is shown; if photoresist is used, light of a set wavelength and a set linear polarization state is used to irradiate the photoresist, and then the first directional groove is formed by developing and etching. The first end of the first electrode 31 is exposed to a portion of the first ITO conductive film 312 with a first wire adhered to it by conductive silver glue to facilitate connection to a power supply to apply voltage.

[0068] The second electrode plate 32 includes a second substrate 321, a second ITO conductive film 322, and a second orientation film 323 arranged in sequence along a direction close to the first electrode plate 31. The second substrate 321 is quartz glass or soda glass. The second orientation film 323 is provided with a plurality of second orientation grooves parallel to each other on a side close to the first electrode plate 31. The second end of the second electrode plate 32 is partially exposed by removing part of the second orientation film 323, preferably leaving the edge area 3221 of the second ITO conductive film 322 exposed as a lead area. The second orientation film 323 is made of polyimide or photoresist. If polyimide is used, the second orientation grooves are formed by rubbing the second orientation film 323 with a flannel cloth. Figure 3 The extension direction 3231 of the second directional groove is shown; if photoresist is used, light of a set wavelength and a set linear polarization state is used to irradiate the photoresist, and then the second directional groove is formed by developing and etching. The second end of the second electrode 32 is exposed to a portion of the second ITO conductive film 322 with a second wire adhered to it by conductive silver glue to facilitate connection to a power supply to apply voltage.

[0069] The second orientation groove is perpendicular to the first orientation groove.

[0070] The liquid crystal 34 is filled into each of the first alignment grooves and each of the second alignment grooves, and initially forms a twisted nematic arrangement.

[0071] Furthermore, the first substrate 311 and the second substrate 321 are preferably rectangular, the first orientation groove is parallel to any long side of the first substrate 311, and the second orientation groove is parallel to any short side of the second substrate 321, so that the first orientation groove and the second orientation groove are perpendicular to each other.

[0072] Furthermore, the spacing between the first electrode 31 and the second electrode 32 is 10μm to 30μm, preferably 20μm; the thickness of the first ITO conductive film 312 is 100nm to 200nm, preferably 200nm, and the thickness of the first orientation film 313 is 50nm to 60nm, preferably 50nm; the thickness of the second ITO conductive film 322 is 100nm to 200nm, preferably 200nm, and the thickness of the second orientation film 323 is 50nm to 60nm, preferably 50nm.

[0073] Preferably, the calibration method of the electrically polarized TN liquid crystal device 3 comprises the following steps:

[0074] 1) Build a calibration system: This system includes a first polarizer 100, a second polarizer 200, and an optical power meter 300, arranged in sequence along the direction of light propagation. Initially, the polarization directions of the first and second polarizers 100 and 200 are parallel. The optical power meter 300 is used to detect the real-time received optical power.

[0075] 2) Rotate the second polarizer 200 according to the set first step length, and stop when the polarization direction of the second polarizer 200 is orthogonal to the polarization direction of the first polarizer 100; wherein, rotating the second polarizer 200 according to the set first step length means pausing the rotation of the second polarizer 200 after each rotation of the set angle, and then the corresponding optical power value after the rotation of the second polarizer 200 can be recorded. For example, initially, the polarization directions of the first polarizer 100 and the second polarizer 200 are parallel. At this time, the initial angle of the second polarizer 200 is set to 0. It is recorded as 0°. The first step length set in this process is preferably 5°. The optical power value of the optical power meter 300 is recorded every time the second polarizer 200 rotates 5°. Therefore, the optical power values ​​are recorded respectively when rotating 5°, 10°, 15°...90°. Therefore, a numerical mapping table between the optical power value and the rotation angle of the second polarizer is obtained, and then curve fitting is performed according to the numerical mapping table (some existing fitting methods can be used, preferably linear fitting, which is more convenient for calculation) to obtain a fitting curve of the optical power value and the rotation angle of the second polarizer 200.

[0076] 3) Place the electrically tunable polarization TN liquid crystal device 3 to be calibrated between the first polarizer 100 and the second polarizer 200. The incident light sequentially passes through the first polarizer 100, the first electrode 31, the second electrode 32, and the second polarizer 200. The second orientation grooves on the second orientation film of the electrically tunable polarization TN liquid crystal device 3 are perpendicular to the polarization direction of the second polarizer 200. At this point, the electrically tunable polarization TN liquid crystal device 3 functions as a continuous polarization rotator. Adjust the voltage according to the set second step size (pause the voltage adjustment after each adjustment to the same set value, and then obtain the corresponding optical power value. For example, if the initial voltage is V0 and the second step size is 0.1V, the voltage is increased by 0.1V each time). This causes the polarization direction of the linearly polarized light incident on the TN liquid crystal device 300 to continuously rotate after exiting the TN liquid crystal device 300. Different optical power values ​​are obtained at this time. Record the corresponding numerical mapping table between the optical power values ​​and voltages during the experiment.

[0077] 4) Through step 3), a numerical mapping table between optical power values ​​and voltages can be obtained. Since the loss of incident light passing through the electrically tunable polarization TN liquid crystal device is very small and can be ignored, each optical power value in the numerical mapping table corresponding to voltage and optical power in step 3) is respectively substituted into the fitting curve of optical power value and rotation angle in step 2), and the corresponding rotation angle of the second polarizer 200 can be obtained. Then, a numerical mapping table between voltage and rotation angle can be obtained. The rotation angle in the numerical mapping table between voltage and rotation angle is used as the polarization angle of the electrically tunable polarization TN liquid crystal device, and the relationship between voltage and polarization angle of the electrically tunable polarization TN liquid crystal device can be obtained. This rotation angle serves as the polarization angle corresponding to the voltage applied in step 3). For example, in step 2), when the rotation angle is 10°, the optical power is 12 mW, and when the rotation angle is 15°, the optical power is 10 mW. When the signal voltage amplitude in the voltage-optical power mapping table in step 3) is 1.4 V, the optical power at this time is 11.5 mW. The rotation angle corresponding to the optical power value in step 3) is recorded as θ, and the polarization rotation angle θ at a certain voltage can be calculated using the following formula combined with the table lookup method:

[0078]

[0079] Then, the rotation angle of 13.75° is used as the polarization angle corresponding to the electrically tunable polarization TN liquid crystal device 3 at a voltage of 1.4 V, so that the voltage-polarization angle relationship of the electrically tunable polarization TN liquid crystal device 3 can be obtained.

[0080] By using the above method, the optical power values ​​obtained in step 3) are respectively substituted into the fitting curve in step 2), and a numerical mapping table and fitting curve of the voltage-polarization angle of the electrically tunable polarization TN liquid crystal device 3 can be obtained. Then, by accurately adjusting the voltage, the polarization angle can be accurately obtained.

[0081] The more accurate the fitting curve is, the more accurate the polarization angle obtained will be.

[0082] By continuously adjusting the twist angle electrically, the polarization direction can be adjusted, which can be used to eliminate strong glare on the water surface in the field of imaging detection and improve the contrast of effective signal detection.

[0083] Determining whether the finished product of the electrically tunable polarization TN liquid crystal device 3 of the present invention meets the parameter requirements can be summarized as follows: (1) Observing the TN (Twisted Nematic) twisting effect under a polarizing microscope to see if it meets the application requirements. (2) Using a multimeter to test the electrical properties to determine whether the first electrode 31 and the second electrode 32 are insulated from each other. (3) Building a voltage-polarization angle calibration system for the electrically tunable polarization TN liquid crystal device 3 to measure the voltage-polarization angle relationship of the electrically tunable polarization TN liquid crystal device 3. The above is the content that needs to be paid attention to during the preparation process of the present invention.

[0084] The following describes in detail the testing process of the electrically polarized TN liquid crystal device 3 according to the embodiment of the present invention:

[0085] 1) First, observe the light modulation effect of the electrically tunable polarization TN liquid crystal device 3 under a polarizing microscope. The polarizer and analyzer behind the polarizing microscope's light source are both adjusted to 0°. The prepared electrically tunable polarization TN liquid crystal device 3 is placed on an observation stand, positioned between the polarizer and analyzer. Light emitted from the light source first passes through the polarizer and then emits 0° linearly polarized light. When the orientation angle of the first orientation film 313 is the same as that of the polarizer, at 0°, the light passes through the electrically tunable polarization TN liquid crystal device 3, with its polarization direction twisted 90° before entering the analyzer, which is positioned at 0°. At this point, the light is blocked by the analyzer, and observation through the eyepiece reveals a black, opaque state. When the device is continuously rotated from 0° to 45°, the eyepiece observation gradually changes from a black, opaque state to a white, translucent state, with the visible light becoming increasingly brighter. Continuously rotating the device in the same direction by 45° also causes the eyepiece observation to gradually change from a white, translucent state to a black, opaque state. This result demonstrates that the prepared TN device achieves a good distortion effect.

[0086] 2) The main operation is to touch the test leads to the first ITO conductive film 312 and the second ITO conductive film 322. This is because by applying voltage to them, the liquid crystal 34 can change its original arrangement under the condition of an external electric field. As the voltage increases, the equivalent twist angle decreases. Therefore, the first ITO conductive film 312 and the second ITO conductive film 322 must be insulated and cannot affect each other in terms of electrical properties. When the resistance between them reaches the megohm level or even higher, it can be determined that the parameter requirements have been met.

[0087] 3) Calibration system test: The voltage-polarization angle relationship of the electrically polarized TN liquid crystal device 3 is obtained through the calibration system.

[0088] According to another aspect of the present invention, a method for preparing the visible light polarization camera is also provided, comprising the following steps:

[0089] 1) Preparation of electrically polarized TN liquid crystal device, as follows:

[0090] 1.1) Preparation of the first electrode plate 31:

[0091] 1.1.1) Cleaning: Ultrasonic cleaning of the first substrate 311 is performed using acetone, isopropyl alcohol, and water in sequence, and then drying;

[0092] 1.1.2) Coating: Electron beam evaporation is used to electroplate conductive metal ITO onto one surface of the cleaned first substrate 311 to form a first ITO conductive film 312, which is then cleaned.

[0093] 1.1.3) Cleaning: Ultrasonic cleaning of the first substrate 311 coated with the first ITO conductive film 312 is performed using acetone, isopropyl alcohol, and water in sequence, each ultrasonic cleaning lasting 5-10 minutes, and then drying;

[0094] 1.1.4) Slicing: Using a wafer slicer, cut the first substrate 311 coated with the first ITO conductive film 312 attached to the blue film or UV film with a blade. After slicing, clean the first substrate 311 coated with the first ITO conductive film 312.

[0095] 1.1.5) Cleaning: Ultrasonic cleaning of the first substrate 311 coated with the first ITO conductive film 312 is performed using acetone, isopropyl alcohol, and water in sequence, and then drying;

[0096] 1.1.6) Glue Coating: Apply a first alignment film 313 to the surface of the first ITO conductive film 312 facing away from the first substrate using a glue coater. The first alignment film 313 is preferably a conventionally rubbed PI film. The rotation speed and holding time of the glue coater are 1200 rpm and 10 seconds, respectively. The glue coating speed and coating time are 3500 rpm and 30 seconds, respectively.

[0097] 1.1.7) Exposing a portion of the first ITO conductive film 312: Transfer the first substrate 311 coated with the first alignment film 313 to a hot plate at 80°C-100°C for preheating for 5 minutes. Before the first alignment film 313 solidifies, use a cotton swab dipped in alcohol to rub the first alignment film 313 to expose a portion of the first ITO conductive film 312 to facilitate voltage application.

[0098] 1.1.8) Curing: After preheating, raise the temperature of the hot plate to 220°C to 240°C to cure the first alignment film 313;

[0099] 1.1.9) Forming first alignment grooves: After the first substrate 311 is cooled, first alignment grooves are formed on the first alignment film 313 to facilitate initial alignment of the liquid crystal molecules;

[0100] 1.2) Preparation of the second electrode plate 32:

[0101] 1.2.1) Taking a second substrate 321 identical to the first substrate 311 sliced ​​in step 1.4), plate a second ITO conductive film 322 on one side of the second substrate 321. Ultrasonic cleaning the second substrate 321 coated with the second ITO conductive film 322 is performed sequentially using acetone, ethanol, and water for 5-10 minutes each, followed by drying.

[0102] 1.2.2) Glue coating: Use a glue spreader to coat the second alignment film 323 on the surface of the second ITO conductive film 322 away from the second substrate;

[0103] 1.2.3) Exposing the Second ITO Conductive Film 322: Transfer the second substrate 321 coated with the second alignment film 323 to a hot plate at 80°C to 100°C for preheating for 5 minutes. Before the second alignment film 323 solidifies, use a cotton swab dipped in alcohol to rub the second alignment film 323 to expose a portion of the second ITO conductive film 322 for easier voltage application.

[0104] 1.2.4) Curing: After preheating, raise the temperature of the hot plate to 220°C to 240°C to cure the second alignment film 323;

[0105] 1.2.5) Forming second alignment grooves: After the second substrate 321 cools down, second alignment grooves are formed on the second alignment film 323 to facilitate the initial alignment of the liquid crystal molecules;

[0106] 1.3) Assembly:

[0107] 1.3.1) Fixing the First and Second Electrode Plates 31 and 32: Arrange the first orientation film 313 of the first electrode plate 31 and the second orientation film 323 of the second electrode plate 32 opposite each other and staggered to leave space for the leads. Ensure that the first orientation groove and the second orientation groove are perpendicular to each other. Use glass microspheres as spacers between the first and second orientation films 313 and 323 to form a cavity between the first and second electrode plates 31 and 32. Adhere the first and second electrode plates 31 and 32 together by mixing AB glue with the spacers.

[0108] 1.3.2) Encapsulation: Liquid crystal 34 is filled into the cavity between the first electrode plate 31 and the second electrode plate 32 by siphoning, and the cavity is sealed with encapsulation material;

[0109] 1.3.3) Lead: Use conductive silver glue to adhere a wire to the portion of the first ITO conductive film 312 exposed at the first end of the first electrode 31, and then use conductive silver glue to adhere a wire to the portion of the second ITO conductive film 322 exposed at the second end of the second electrode 32. Then heat and dry the conductive silver glue. The drying temperature of the conductive silver glue is 300°C to 400°C.

[0110] 2) Mount the electrically polarized TN liquid crystal device 3 and analyzer 4 on the internal bracket 2, then mount the internal bracket 2 and image sensor 53 within the camera housing. Mount the camera lens 12 and image output unit 51 on the camera housing, ensuring that the camera lens 12, electrically polarized TN liquid crystal device 3, analyzer 4, image sensor 53, and image output unit 51 are arranged sequentially along the optical path. A three-dimensional machining diagram for the camera housing can be drawn based on existing standard camera lens 12. The internal bracket 2 primarily serves to position the electrically polarized TN liquid crystal device 3 and analyzer 4 in the optical path. It should also include a reserved interface for the detection system 5 to facilitate mounting the liquid crystal device on the detector surface. The detection system 5 can be fabricated based on existing designs and mechanical component drawings. These components should include interfaces for the internal bracket 2. The components should be fabricated according to the drawings and then aligned and debugged with the camera lens 12 and internal bracket 2 components to ensure mechanical accuracy. According to the designed mechanical components of the detection system 5 , the image output unit 51 of the detection system 5 is debugged to ensure the good operation of the detection system 5 .

[0111] According to another aspect of the present invention, an application of the visible light polarization camera is also provided. A voltage is continuously increased between the first ITO conductive film 312 of the first electrode 31 and the second ITO conductive film 322 of the second electrode 32 through a power supply, so that the long axis of the liquid crystal molecules is arranged along the electric field lines under the action of the external electric field, thereby changing the polarization direction of the linearly polarized light. The liquid crystal molecules gradually deflect from the 90° twist angle in the initial state to the point where the long axis of the liquid crystal molecules is perpendicular to the first substrate. That is, when no voltage is applied to the liquid crystal molecules at the beginning, the twist angle of the liquid crystal molecules is 90°. When the voltage is increased to a certain value, the twist angle is between 0° and 90°. When the voltage is further increased to the maximum value, the twist angle of the liquid crystal molecules is 0°, thereby achieving continuous adjustment of the polarization angle of the incident light.

[0112] This polarization camera can selectively highlight or shield the detection efficiency of a specific polarization state in the target. Specifically, by inserting an electrically adjustable polarization TN liquid crystal device 3 into the original camera optical path, the polarization angle of the incident light can be electrically adjusted and rotated. When the polarization angle of a target is twisted by the liquid crystal device and becomes perpendicular to the analyzer 4 in front of the CMOS, this part of the light cannot pass through. Conversely, the light parallel to the analyzer 4 can be detected by the CMOS. When the polarization angle of the light emitted by the liquid crystal device is at an intermediate angle of 0° to 90° relative to the transmission axis of the analyzer 4, the target brightness changes from bright to dark, thereby improving the detection and recognition effect of multi-polarization complex targets.

[0113] Alternatively, by adjusting the signal voltage according to the set second step size, continuous adjustment of the polarization angle of the incident light can be achieved. In the early stage, it is necessary to use a calibration optical path system to mark the polarization rotation angle of each voltage amplitude modulation; alternatively, by obtaining the voltage-polarization angle relationship of the electrically adjustable polarization TN liquid crystal device 3, the polarization direction of the incident light can be continuously electrically adjusted and twisted. This can be applied to practical scenarios such as eliminating strong glare on the water surface and defogging in bad weather in the field of imaging detection, thereby improving the effective signal detection contrast.

[0114] Furthermore, the power supply is an AC power supply, the signal type is a sine wave or a bipolar square wave with a 50% duty cycle, the voltage changes linearly and continuously in the range of 0.01V to 20.00V, and the signal frequency is in the range of 1KHz to 5KHz.

[0115] Determining whether the finished visible light polarization camera system based on an electrically tunable polarization TN liquid crystal device 3 meets the required parameters can be summarized in the following two points: (1) Observing whether the electrically tunable polarization TN liquid crystal device 3 is used in the camera's optical path. (2) Building a voltage-polarization angle calibration system for the electrically tunable polarization TN liquid crystal device 3, measuring the voltage-polarization angle relationship of the electrically tunable polarization TN liquid crystal device 3, capturing images based on this relationship, and determining whether the system has polarization selection functionality. The above are the key points to note during the preparation process of the present invention.

[0116] Testing process of the electrically polarized TN liquid crystal device 3 of the present invention:

[0117] 1) First, observe whether an electrically polarized TN liquid crystal device 3 is used as a polarization modulation optical element in the camera optical path.

[0118] 2) Then, according to the corresponding relationship, different voltages are adjusted to capture images, and it is determined whether the images have different polarization selection effects for different voltages.

[0119] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A visible light polarization camera comprising a camera lens, an electrically polarized TN liquid crystal device, an analyzer, an image sensor, and an image output unit arranged in sequence along an optical path, wherein the camera lens and the image output unit are mounted on and exposed from a camera housing, the electrically polarized TN liquid crystal device and the analyzer are mounted on an internal bracket, and the image sensor and the internal bracket are mounted within the camera housing. The camera is characterized in that: The electrically polarized TN liquid crystal device includes a first plate, a second plate, a spacer group, and liquid crystal, wherein the first plate and the second plate are parallel to each other and there is a distance between them, the spacer group is arranged between the first plate and the second plate, the liquid crystal is sealed and installed between the first plate and the second plate, the first end of the first plate extends beyond the first end of the second plate, and the second end of the second plate extends beyond the second end of the first plate, wherein the first end of the first plate and the second end of the first plate are arranged oppositely, and the first end of the second plate and the second end of the second plate are arranged oppositely, so that the first plate and the second plate are staggered; the first plate includes a plurality of electrodes arranged in sequence along a direction close to the second plate. a first substrate, a first ITO conductive film, and a first orientation film, wherein a surface of the first orientation film close to the second electrode plate is provided with a plurality of mutually parallel first orientation grooves, and a first end of the first electrode plate is partially exposed by removing a portion of the first orientation film; the second electrode plate comprises a second substrate, a second ITO conductive film, and a second orientation film sequentially arranged along a direction close to the first electrode plate, wherein a surface of the second orientation film close to the first electrode plate is provided with a plurality of mutually parallel second orientation grooves, and a second end of the second electrode plate is partially exposed by removing a portion of the second orientation film, the second orientation grooves are perpendicular to the first orientation grooves, and the liquid crystal is filled in each of the first orientation grooves and each of the second orientation grooves; The image sensor is a CMOS image sensor, the first substrate is quartz glass or soda glass, and the second substrate is quartz glass or soda glass.

2. The visible light polarization camera according to claim 1, wherein: The first alignment film is made of polyimide or photoresist. If polyimide is used, the first alignment groove is formed by rubbing the first alignment film with a flannel. If photoresist is used, the photoresist is irradiated with light of a set wavelength and a set linear polarization state, and then the first alignment groove is formed by developing and etching. The second alignment film is made of polyimide or photoresist. If polyimide is used, the second alignment groove is formed by rubbing the second alignment film with a flannel. If photoresist is used, light of a set wavelength and a set linear polarization state is used to irradiate the photoresist, and then the second alignment groove is formed by developing and etching.

3. The visible light polarization camera according to claim 1, wherein: The distance between the first electrode plate and the second electrode plate is 10 μm to 30 μm; The thickness of the first ITO conductive film is 100 nm to 200 nm, and the thickness of the first orientation film is 50 nm to 60 nm; The thickness of the second ITO conductive film is 100 nm to 200 nm, and the thickness of the second alignment film is 50 nm to 60 nm.

4. The visible light polarization camera according to claim 1, wherein: A first wire is adhered to a portion of the first ITO conductive film exposed at the first end of the first electrode plate via conductive silver glue; A second wire is adhered to a portion of the second ITO conductive film exposed at the second end of the second electrode plate via conductive silver glue.

5. The visible light polarization camera according to claim 1, wherein: The calibration method of the electrically polarized TN liquid crystal device comprises the following steps: 1) Build a calibration system: The calibration system includes a first polarizer, a second polarizer, and an optical power meter arranged in sequence along the propagation direction of light. Initially, the polarization directions of the first and second polarizers are parallel. The optical power meter is used to detect the real-time received optical power. 2) Rotate the second polarizer according to the set first step length until the polarization direction of the second polarizer is orthogonal to the polarization direction of the first polarizer. During this process, record the optical power value of the optical power meter to obtain a numerical mapping table and fitting curve between the optical power value and the rotation angle of the second polarizer; 3) Placing the electrically tunable polarization TN liquid crystal device to be calibrated between a first polarizer and a second polarizer, with incident light sequentially passing through the first polarizer, the first electrode plate, the second electrode plate, and the second polarizer, and with the second orientation groove on the second orientation film of the electrically tunable polarization TN liquid crystal device perpendicular to the polarization direction of the second polarizer; adjusting the voltage according to a set second step size to obtain the optical power value corresponding to each voltage, thereby obtaining a numerical mapping table between the optical power value and the voltage; 4) Substituting each optical power value obtained in step 3) into the fitting curve of the optical power value and the rotation angle obtained in step 2) to obtain the corresponding rotation angle, a numerical mapping table of voltage and the rotation angle of the second polarizer is obtained. The rotation angle of the second polarizer is used as the polarization angle of the electrically tunable polarization TN liquid crystal device, and a numerical mapping table and fitting curve of voltage and polarization angle of the electrically tunable polarization TN liquid crystal device are obtained.

6. The method for preparing a visible light polarization camera according to any one of claims 1 to 5, wherein: The following steps are involved: 1) Preparation of electrically polarized TN liquid crystal device, as follows: 1.1) Preparation of the first electrode plate: 1.1.1) Cleaning: Ultrasonic clean the first substrate using acetone, isopropyl alcohol, and water in sequence, and then dry it. 1.1.2) Coating: Electron beam evaporation is used to electroplate conductive metal ITO onto one surface of the cleaned first substrate to form a first ITO conductive film, which is then cleaned. 1.1.3) Cleaning: Ultrasonic cleaning of the first substrate coated with the first ITO conductive film is performed using acetone, isopropyl alcohol, and water in sequence, followed by drying; 1.1.4) Slicing: Using a wafer slicer, cut the first substrate coated with the first ITO conductive film attached to the blue film or UV film using a blade. After slicing, clean the first substrate coated with the first ITO conductive film. 1.1.5) Cleaning: Ultrasonic cleaning of the first substrate coated with the first ITO conductive film is performed using acetone, isopropyl alcohol, and water in sequence, followed by drying; 1.1.6) Glue coating: Use a coating machine to apply the first alignment film on the surface of the first ITO conductive film away from the first substrate; 1.1.7) Expose a portion of the first ITO conductive film: Transfer the first substrate coated with the first alignment film to a hot plate for preheating. Before the first alignment film solidifies, use a cotton swab dipped in alcohol to rub the first alignment film to expose a portion of the first ITO conductive film to facilitate voltage application. 1.1.8) Curing: After preheating, increase the temperature of the hot plate to cure the first oriented film; 1.1.9) Forming first alignment grooves: After the first substrate cools down, first alignment grooves are formed on the first alignment film to facilitate the initial alignment of the liquid crystal molecules. 1.2) Preparation of the second electrode plate: 1.2.1) Take a second substrate identical to the first substrate sliced ​​in step 1.4), coat one side of the second substrate with a second ITO conductive film, and ultrasonically clean the second substrate coated with the second ITO conductive film using acetone, ethanol, and water, followed by drying. 1.2.2) Glue coating: Use a glue spreader to apply the second alignment film on the surface of the second ITO conductive film away from the second substrate; 1.2.3) Expose the Second ITO Conductive Film: Transfer the second substrate coated with the second alignment film to a hot plate for preheating. Before the second alignment film solidifies, use a cotton swab dipped in alcohol to rub the second alignment film to expose a portion of the second ITO conductive film to facilitate voltage application. 1.2.4) Curing: After preheating, increase the temperature of the hot plate to solidify the second oriented film; 1.2.5) Forming Second Orientation Grooves: After the second substrate cools down, second orientation grooves are formed on the second orientation film to facilitate the initial orientation of the liquid crystal molecules. 1.3) Assembly: 1.3.1) Fixing the First and Second Plates: Arrange the first orientation film of the first plate and the second orientation film of the second plate opposite each other and staggered to leave space for the leads. Ensure that the first orientation groove and the second orientation groove are perpendicular to each other. Use glass microspheres as spacers between the first and second orientation films to form a cavity between the first and second plates. Adhere the first and second plates together by mixing AB glue with the spacers. 1.3.2) Encapsulation: Liquid crystal is filled into the cavity between the first and second plates by siphoning, and the cavity is sealed with encapsulation material; 1.3.3) Leads: Use conductive silver glue to adhere a wire to the portion of the first ITO conductive film exposed at the first end of the first electrode. Then, use conductive silver glue to adhere a wire to the portion of the second ITO conductive film exposed at the second end of the second electrode. Heat and dry the conductive silver glue. 2) Installing the electrically polarized TN liquid crystal device and the analyzer on the internal bracket respectively, installing the internal bracket and the image sensor in the camera housing respectively, and installing the camera lens and the image output unit on the camera housing respectively, ensuring that the camera lens, the electrically polarized TN liquid crystal device, the analyzer, the image sensor, and the image output unit are arranged in sequence along the optical path.

7. Use of the visible light polarization camera according to any one of claims 1 to 4, characterized in that: The voltage is continuously increased between the first ITO conductive film of the first electrode plate and the second ITO conductive film of the second electrode plate through a power supply, so that the long axis of the liquid crystal molecules is arranged along the electric field lines under the action of the external electric field, and the liquid crystal molecules are gradually deflected from the 90° twist angle in the initial state to the long axis of the liquid crystal molecules being perpendicular to the first substrate, thereby realizing continuous adjustment of the polarization angle of the incident light.

8. The use of the visible light polarization camera according to claim 7, characterized in that: The power supply is an AC power supply, the signal type is a sine wave or a bipolar square wave with a 50% duty cycle, the voltage changes linearly and continuously in the range of 0.01V to 20.00V, and the signal frequency is in the range of 1KHz to 5KHz.

Images