A dynamic edge detection device, a preparation method thereof and a dynamic edge detection apparatus

Abstract

The application discloses a dynamic edge detection device and a preparation method and a dynamic edge detection device thereof. The dynamic edge detection device comprises oppositely arranged first and second substrates and a ferroelectric liquid crystal layer. The first substrate is provided with a first transparent electrode layer on one side, and the second substrate is provided with a second transparent electrode layer on one side. The first substrate is provided with an orientation layer on the side facing the second substrate. The ferroelectric liquid crystal layer comprises ferroelectric liquid crystal molecules forming a layered helical structure, and the optical axis presents a circularly changing arrangement and an angular distribution. In the case of applying an external electric field perpendicular to the first substrate and with a voltage greater than or equal to a threshold voltage, the helical structure of the ferroelectric liquid crystal layer is disentangled. The dynamic edge detection device provided by the application has electrically controllable adjustable optical axes. When linearly polarized light is incident, the outgoing vector polarization rotation can be realized by changing the polarity of the applied electric field, thereby realizing the edge switching in the orthogonal dimension, and high-speed and high-efficiency one-dimensional optical image edge detection in any direction is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ferroelectric liquid crystal and optical edge detection, and particularly relates to a dynamic edge detection device and a preparation method thereof, and a dynamic edge detection device. BACKGROUND

[0002] An edge is important feature information in an image, and therefore edge detection is usually the first step of data compression, target detection and feature classification, and is currently widely applied in the fields of medical imaging, face recognition and automatic driving of a car. In recent years, with the development of artificial intelligence and the like, the amount of image processing data has increased explosively, and higher requirements are put forward for fast calculation, low energy consumption and parallel processing. However, the traditional digital calculation mode is limited by hardware conditions, and the processing speed is limited, and there is a relatively high power consumption under a large amount of data. Full-optical analog calculation uses photons as information carriers, and the processing speed can theoretically reach the speed of light. In addition, large-flux parallel processing can be performed, and the analog characteristics make the output results of image processing usually visualized. Optical edge detection provides a feasible solution for new requirements.

[0003] Spatial differentiation is a common means to realize edge detection. Compared with traditional amplitude filters and wavefront modulation means, micro-nano structures and devices provide more possibilities for spatial differentiation operation due to their compactness, ease of integration and the like. Optical edge detection devices based on photonic crystals, photonic chips and superstructures and the like novel materials are beneficial to high-speed parallel calculation, large-flux image processing, real-time target recognition and the like application scenarios. However, most devices and structures are fixed after manufacturing, lack of adjustability, and have single function, which limits the development of optical edge detection devices and application in related fields. SUMMARY

[0004] The embodiment of the present application provides a dynamic edge detection device and a preparation method thereof and a dynamic edge detection device. The dynamic edge detection device has an electrically controllable adjustable optical axis. When linearly polarized light is incident, the outgoing vector polarization rotation can be realized by changing the polarity of an applied electric field, so that the edge switching in orthogonal dimensions is realized, and one-dimensional optical image edge detection in any direction is realized at high speed and high efficiency.

[0005] According to an aspect of the present application, a dynamic edge detection device is provided, comprising a first substrate, a second substrate arranged oppositely, and a ferroelectric liquid crystal layer located between the first substrate and the second substrate.

[0006] A first transparent electrode layer is arranged on one side of the first substrate facing the second substrate, and a second transparent electrode layer is arranged on one side of the second substrate facing the first substrate.

[0007] The first transparent electrode layer is provided with an alignment layer on the side facing the second substrate, and the control pattern of the alignment layer presents a ring-shaped gradient arrangement or an angular distribution.

[0008] The ferroelectric liquid crystal layer comprises ferroelectric liquid crystal molecules, which form a layered helical structure, the helical axis of the layered helical structure is parallel to the plane of the first substrate, and the arrangement direction of the helical axis presents a ring-shaped gradient arrangement or an angular distribution according to the control pattern of the alignment layer.

[0009] When an external electric field is applied between the first transparent electrode layer and the second transparent electrode layer, which is perpendicular to the first substrate and has a voltage greater than or equal to a threshold voltage, the helical structure of the ferroelectric liquid crystal layer is disentangled.

[0010] When different voltages are applied between the first transparent electrode layer and the second transparent electrode layer, the dynamic edge detection device achieves different edge detection effects.

[0011] Optionally, a spacer is arranged between the first substrate and the second substrate, and the spacer is used to support the first substrate and the second substrate to form a containing space for the ferroelectric liquid crystal layer.

[0012] Optionally, the size of the spacer in the direction perpendicular to the plane of the first substrate is greater than or equal to the pitch of the layered helical structure.

[0013] Optionally, the ferroelectric liquid crystal layer comprises a chiral smectic C phase ferroelectric liquid crystal, the normal line of the smectic layer of the chiral smectic C phase ferroelectric liquid crystal is always parallel to the plane of the first substrate, and presents a helical structure without an external electric field, the helical axis of which is always parallel to the plane of the first substrate, and the pitch of the helical axis is smaller than the distance between the first substrate and the second substrate.

[0014] Optionally, when an external electric field is applied between the first transparent electrode layer and the second transparent electrode layer, which is perpendicular to the first substrate and has a voltage greater than or equal to a threshold voltage, the director of the ferroelectric liquid crystal molecules will rotate to the side parallel to a substrate on the helical cone surface according to the polarity of the electric field.

[0015] When the polarity of the external electric field is reversed, the director of the ferroelectric liquid crystal molecules will rotate to the corresponding other side.

[0016] Optionally, the arrangement direction of the helical axis presents a ring-shaped gradient arrangement or an angular distribution without an external electric field, and the distribution of the equivalent optical axis satisfies α = φ / 2 + α0.

[0017] In the case that an external electric field is applied perpendicularly to the first substrate and the voltage is greater than or equal to a threshold voltage, the director of the de-twisted ferroelectric liquid crystal molecule presents a ring-shaped gradient arrangement and an angular distribution.

[0018] When the overall optical axis distribution changes after power-on, when a positive voltage is applied, the equivalent optical axis distribution satisfies α=φ / 2+α0+θ, and when a negative voltage is applied, the equivalent optical axis distribution satisfies α=φ / 2+α0-θ.

[0019] Wherein, φ is an azimuth angle, α0 is an initial angle of the equivalent optical axis, and θ is a tilt angle of the ferroelectric liquid crystal.

[0020] Optionally, by applying external electric fields with different polarities to the ferroelectric liquid crystal layer, rotation transformation of the vector light beam is realized, the linear polarization direction at the same spatial position is synchronously rotated, and a vector light beam with another polarization distribution is formed.

[0021] According to another aspect of the present application, a preparation method of a dynamic edge detection device is provided, which is used for preparing the above-mentioned dynamic edge detection device, and the preparation method comprises the following steps:

[0022] A first substrate and a second substrate are provided;

[0023] A first transparent electrode layer is formed on one side of the first substrate, and a second transparent electrode layer is formed on one side of the second substrate;

[0024] An orientation layer is formed on one side of the first substrate;

[0025] The first substrate and the second substrate are arranged opposite to each other;

[0026] The orientation layer is oriented to form a target control pattern;

[0027] A ferroelectric liquid crystal layer is formed between the first substrate and the second substrate to form the dynamic edge detection device;

[0028] Wherein, the first transparent electrode layer is located on the side of the first substrate facing the second substrate, the second transparent electrode layer is located on the side of the second substrate facing the first substrate, the orientation layer is located on the side of the first substrate facing the second substrate, the control pattern of the orientation layer presents a ring-shaped gradient arrangement and an angular distribution, and the ferroelectric liquid crystal layer is oriented according to the target control pattern.

[0029] Optionally, after the first substrate and the second substrate are arranged opposite to each other, the method further comprises the following steps:

[0030] A spacer is arranged between the first substrate and the second substrate.

[0031] According to another aspect of the present application, a dynamic edge detection device is provided, comprising an external electric field regulating unit, and a laser, a target object, a first polarizer, a first lens, the dynamic edge detection device, a second lens, a second polarizer and an imaging device arranged in sequence on the same optical axis;

[0032] The light beam output by the laser passes through the first polarizer and the first lens in sequence, is incident from the first substrate side of the dynamic edge detection device, the dynamic edge detection device performs geometric phase modulation on the incident linearly polarized light beam, and the outgoing light beam passes through the second lens and the second polarizer in sequence and is received by the imaging device after being transmitted.

[0033] The imaging device receives a one-dimensional edge image of the target object; the external electric field regulating unit is used to regulate the external electric field environment in which the dynamic edge detection device is located; changing the polarity of the external electric field causes the polarization direction of the outgoing vector light beam to rotate after passing through the dynamic edge detection device, and the direction of the one-dimensional edge image of the image is selectively switched.

[0034] The dynamic edge detection device provided by the embodiment of the present application comprises oppositely arranged first and second substrates and a ferroelectric liquid crystal layer between the first and second substrates, the ferroelectric liquid crystal layer presents a layered helical structure without an external electric field, and the helical axis of the layered helical structure is parallel to the plane of the first substrate; the side of the first substrate facing the second substrate is provided with a first transparent electrode layer, and the side of the second substrate facing the second substrate is provided with a second transparent electrode layer; the side of the first transparent electrode layer facing the second substrate is provided with an orientation layer, and the control pattern of the orientation layer presents a ring-shaped gradient arrangement and an angular distribution. In the case that an external electric field is applied between the first and second transparent electrode layers and is perpendicular to the first substrate and has a voltage greater than or equal to a threshold voltage, the helical structure of the ferroelectric liquid crystal layer is disentangled, and the director of the ferroelectric liquid crystal molecule rotates to the side of the helical cone plane parallel to one substrate according to the polarity of the electric field, and when the polarity of the external electric field changes, the director of the ferroelectric liquid crystal molecule will rotate to the corresponding other side. The distribution direction of the director of the disentangled ferroelectric liquid crystal molecule still presents a ring-shaped gradient arrangement and an angular distribution, and the overall optical axis distribution changes after power-on compared with the case without an electric field. The dynamic edge detection device provided by the embodiment of the present application has a polarization rotation modulation effect on a vector light field, and the rotation transformation of a vector light beam can be realized by applying an external electric field with different polarities, the linear polarization direction at the same spatial position is synchronously rotated, and a vector light beam with another polarization distribution is formed. Therefore, the dynamic edge detection device provided by the embodiment of the present application can realize high-speed and efficient one-dimensional optical image edge detection in any direction. The device has an electrically controllable adjustable optical axis, and when linearly polarized light is incident, the outgoing vector polarization rotation can be realized by changing the polarity of the external electric field, thereby realizing edge switching in the orthogonal dimension, and effectively improving the limitations of the traditional optical edge detection device, such as non-adjustable and fixed function.

[0035] It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the present application or to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 A structural schematic diagram of a dynamic edge detection device provided by the embodiment of the present application;

[0038] Figure 2A bottom view schematic diagram of a ferroelectric liquid crystal layer structure of a dynamic edge detection device provided by an embodiment of the present application;

[0039] Figure 3 An equivalent optical axis distribution of a ferroelectric liquid crystal layer of a dynamic edge detection device provided by an embodiment of the present application in the absence of an applied electric field and an optical axis distribution under different polar applied electric fields;

[0040] Figure 4 A vector diffraction spot diagram of a dynamic edge detection device provided by an embodiment of the present application under different polar applied electric fields;

[0041] Figure 5 A flowchart of a preparation method of a dynamic edge detection device provided by an embodiment of the present application;

[0042] Figure 6 A structural schematic diagram of a dynamic edge detection device provided by an embodiment of the present application;

[0043] Figure 7 An edge detection result diagram of a dynamic edge detection device provided by an embodiment of the present application;

[0044] Figure 8 A switching response time diagram of a dynamic edge detection device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the personnel in the art better understand the present application scheme, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the personnel in the art without creative labor should belong to the protection scope of the present application.

[0046] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0047] Figure 1A structural schematic diagram of a dynamic edge detection device is provided for an embodiment of the present application, referring to Figure 1 The dynamic edge detection device comprises a first substrate 10, a second substrate 20 arranged oppositely, and a ferroelectric liquid crystal layer 30 between the first substrate 10 and the second substrate 20; a first transparent electrode layer is arranged on the side of the first substrate 10 facing the second substrate 20, and a second transparent electrode layer is arranged on the side of the second substrate 20 facing the first substrate 10 (the first transparent electrode layer and the second transparent electrode layer are not shown in the figure). Figure 1 An orientation layer 40 is arranged on the side of the first transparent electrode layer facing the second substrate 20, and the control pattern of the orientation layer 40 presents a ring-shaped gradient arrangement and an angular distribution. Figure 2 A bottom view schematic diagram of the ferroelectric liquid crystal layer structure of the dynamic edge detection device is provided for an embodiment of the present application, referring to Figure 2 The ferroelectric liquid crystal layer 30 comprises ferroelectric liquid crystal molecules 31, and a plurality of ferroelectric liquid crystal molecules 31 form a layered helical structure, the helical axis of the layered helical structure is parallel to the plane of the first substrate, and the arrangement direction of the helical axis presents a ring-shaped gradient arrangement and an angular distribution according to the control pattern of the orientation layer. In the case of applying an external electric field perpendicular to the first substrate 10 between the first transparent electrode layer and the second transparent electrode layer and the voltage is greater than or equal to the threshold voltage, the helical structure of the ferroelectric liquid crystal layer 30 is disentangled; wherein when different voltages are applied between the first transparent electrode layer and the second transparent electrode layer, the dynamic edge detection device achieves different edge detection effects.

[0048] Among them, the first substrate 10 and the second substrate 20 can be a flexible substrate, such as a polyimide substrate, or a rigid substrate, such as a quartz substrate or a glass substrate. Optionally, the orientation material in the orientation layer 40 can be at least one of photo-crosslinking material, photo-degradation material and photo-induced cis-trans isomerization material, such as photosensitive azo material SD1. These materials are photo-controlled orientation materials, which can undergo physical or chemical reactions under the irradiation of linearly polarized ultraviolet light, thereby inducing the directional arrangement of liquid crystal molecules. The ferroelectric liquid crystal layer 30 exhibits a layered helical topological structure under the anchoring effect of the orientation layer 40. In the absence of an external electric field, the equivalent optical axis of the ferroelectric liquid crystal layer 30 presents a ring-shaped gradient arrangement and an angular distribution.

[0049] Optionally, referring to Figure 1 The dynamic edge detection device further comprises a spacer 50 arranged between the first substrate 10 and the second substrate 20, and the spacer 50 is used to support the first substrate 10 and the second substrate 20 to form a containing space for the ferroelectric liquid crystal layer 30.

[0050] The spacer 50 can be a quartz microsphere or a quartz column, and can be arranged at the boundary position of the first substrate 10 and the second substrate 20 to support the first substrate 10 and the second substrate 20 and form a filling space of the ferroelectric liquid crystal layer 30. Optionally, the size of the spacer 50 in the direction perpendicular to the plane of the first substrate 10 is greater than or equal to the pitch of the layered helical structure. In a specific implementation, the height of the spacer 50 can be much greater than the pitch of the layered helical structure. It can be understood that, Figure 1 The position relationship of the spacer 50 for supporting the first substrate 10 and the second substrate 20 is only exemplarily shown, but not the actual size and proportion.

[0051] For example, in an embodiment of the present application, the pitch of the selected ferroelectric liquid crystal material is 245 nm, the spontaneous polarization is 110 nC / cm 2 , and the thickness of the ferroelectric liquid crystal layer is 1.5 μm. It should be noted that the pitch and thickness of the ferroelectric liquid crystal material described above are only exemplary descriptions, and are not a limitation on the embodiments of the present application. In other embodiments, other pitches and thicknesses can be used according to specific needs.

[0052] Optionally, the ferroelectric liquid crystal layer 30 includes a chiral smectic C phase ferroelectric liquid crystal, the layer normal of the smectic layer of the chiral smectic C phase ferroelectric liquid crystal is always parallel to the plane of the first substrate 10, and the chiral smectic C phase ferroelectric liquid crystal presents a helical structure without an applied external electric field, the helical axis of the helical structure is always parallel to the plane of the first substrate 10, and the pitch of the helical axis is less than the distance between the first substrate 10 and the second substrate 20.

[0053] Optionally, in the case of applying an external electric field perpendicular to the first substrate 10 and having a voltage greater than or equal to a threshold voltage between the first transparent electrode layer and the second transparent electrode layer, the director of the ferroelectric liquid crystal molecules will rotate to one side parallel to one substrate on the helical cone according to the polarity of the electric field; when the polarity of the applied electric field is reversed, the director of the ferroelectric liquid crystal molecules will rotate to the corresponding other side.

[0054] Optionally, the orientation direction of the helical axis presents a ring-shaped gradient arrangement and an angular distribution without an applied external electric field, and the distribution of the equivalent optical axis satisfies α = φ / 2 + α0; in the case of applying an external electric field perpendicular to the first substrate and having a voltage greater than or equal to a threshold voltage, the director of the ferroelectric liquid crystal molecules after uncoiling presents a ring-shaped gradient arrangement and an angular distribution; when the electric is applied, the distribution of the overall optical axis changes, when a positive electric is applied, the distribution of the equivalent optical axis satisfies α = φ / 2 + α0+ θ, and when a negative electric is applied, the distribution of the equivalent optical axis satisfies α = φ / 2 + α0- θ; where φ is an azimuth angle, α0is an initial angle of the equivalent optical axis, and θ is a tilt angle of the ferroelectric liquid crystal.

[0055] Optionally, by applying an external electric field with different polarities to the ferroelectric liquid crystal layer, the rotation transformation of the vector light beam is realized, the linear polarization direction at the same spatial position is synchronously rotated, and a vector light beam with another polarization distribution is formed.

[0056] Exemplarily, Figure 3 The dynamic edge detection device provided in the embodiment of the present application is provided with a schematic diagram of the equivalent optical axis distribution of the ferroelectric liquid crystal layer under no external electric field and the optical axis distribution under different polarities of the external electric field. Figure 3 Under the influence of the orientation layer control pattern, the ferroelectric liquid crystal layer forms a ring-shaped gradient arrangement and an angularly distributed spiral layer structure. Under no external electric field stimulation, the optical axis distribution of the ferroelectric liquid crystal layer satisfies α = φ / 2. The structure of the ferroelectric liquid crystal layer changes under the external electric field environment. When the external electric field applied is greater than or equal to the threshold voltage, the spiral structure of the ferroelectric liquid crystal layer will be disentangled, and the director of the ferroelectric liquid crystal molecules will be uniformly rotated to the side parallel to the first substrate on the spiral cone surface according to the polarity of the electric field. When the polarity is reversed, the director of the ferroelectric liquid crystal molecules will be uniformly rotated to the other side. The corresponding equivalent optical axis will be rotated by an angle θ, wherein θ is the tilt angle of the ferroelectric liquid crystal molecules. Exemplarily, when a positive polarity external electric field is applied, the optical axis distribution of the ferroelectric liquid crystal layer satisfies α = φ / 2 + θ, and when a negative polarity external electric field is applied, the optical axis distribution of the ferroelectric liquid crystal layer satisfies α = φ / 2 - θ. Exemplarily, in the embodiment of the present application, the tilt angle of the selected ferroelectric liquid crystal material is 25°, and the best edge effect can be switched in the orthogonal direction when the tilt angle θ is 22.5°, wherein 22.5° is the theoretical best value, and the tilt angle set in the specific implementation is 25° due to the limitations of the used material. Figure 3 When θ is 25°, the optical axis distribution of the ferroelectric liquid crystal layer satisfies α = φ / 2 + 25° when a positive polarity external electric field is applied, and satisfies α = φ / 2 - 25° when a negative polarity external electric field is applied.

[0057] It should be noted that, Figure 3 The schematic diagram of the equivalent optical axis distribution of the ferroelectric liquid crystal layer under no external electric field and the optical axis distribution under different polarities of the external electric field in the dynamic edge detection device is only exemplarily shown in the embodiment, but is not a limitation on the ferroelectric liquid crystal material used in the present application. In other embodiments, ferroelectric liquid crystal materials with other optical properties can be selected according to actual needs.

[0058] Exemplarily, Figure 4 The vector diffraction spot diagram of the dynamic edge detection device provided in the embodiment of the present application under different polarities of the external electric field. Figure 4 The upper row in the figure is the vector spot under the positive polarity measured in the experiment, and the lower row is the vector spot under the negative polarity. Reference Figure 4When linearly polarized light with a wavelength of 550 nm is incident, under different polar external electric field environments, the diffraction light spots all present a circular ring-shaped light intensity distribution, but the polarization distribution of the outgoing vector light field is different, and the polarization direction rotates about 100°. After polarization detection, the light spot is divided into two petals by an oblique dark stripe, and the light spot pattern rotates with the change of the polarity. According to different polarization detection conditions and different electric field conditions, it can be seen that the polarization distribution of the vector light beam has a quantitative rotation.

[0059] The dynamic edge detection device provided by the embodiment of the application can realize one-dimensional edge imaging of a target object in a specific direction, and can quickly switch the edge images in two orthogonal directions. For example, under a positive polarity external electric field environment, the vertical edge detection of the target object can be realized, and when the external electric field is negative, the horizontal edge detection of the target object can be realized. The dynamic edge detection device can effectively improve the limitations of conventional optical edge detection devices, such as lack of adjustability and limited functions.

[0060] Figure 5 The flowchart of the preparation method of the dynamic edge detection device provided by the embodiment of the application is used to prepare the dynamic edge detection device provided by the above embodiment, and the preparation method is described in detail with reference to Figure 5 The preparation method comprises the following steps.

[0061] S110, a first substrate and a second substrate are provided.

[0062] The first substrate and the second substrate can be a flexible substrate or a rigid substrate with high light transmittance (greater than or equal to 85%), for example, the material of the first substrate and the second substrate can be glass, and the thickness of the substrate can be 1mm-2mm.

[0063] S120, a first transparent electrode layer is formed on one side of the first substrate, and a second transparent electrode layer is formed on one side of the second substrate.

[0064] The first electrode layer and the second electrode layer can be indium tin oxide (ITO), and in other embodiments, a substrate including an ITO electrode can be directly used, and the step of the transparent electrode layer can be omitted.

[0065] S130, an alignment layer is formed on one side of the first substrate.

[0066] The alignment layer formed on one side of the first substrate comprises the following steps.

[0067] A solution containing the orienting material is spin-coated on one side of the first substrate. After the spin-coating is completed, the first substrate is annealed to form the orienting layer. In an example, the orienting material is a photosensitive azo material SD1, and the spin-coating solution contains 0.35% of SD1 and 99.65% of dimethylformamide.

[0068] In an example, the spin-coating process can include: first adjusting the rotation speed to 600-900 rpm, and controlling the first-stage spin-coating time to 5-10 s to make the material uniformly distributed on the surface of the substrate; and then adjusting the rotation speed to 2500-3500 rpm, and controlling the second-stage spin-coating time to 30-50 s to make the material spread to a specific thickness. Optionally, the thickness of the orienting layer can be 30-50 nm.

[0069] In an example, the annealing process can include: an annealing atmosphere of air, an annealing temperature of 80-120℃, and an annealing time of 8-12 min.

[0070] It should be noted that the above-mentioned spin-coating solution composition, spin-coating parameters, and annealing parameters are only exemplary descriptions, and in other embodiments, they can be adjusted according to actual needs.

[0071] S140, the first substrate and the second substrate are opposed.

[0072] The orienting layer is located on the side of the first substrate facing the second substrate when the first substrate and the second substrate are opposed.

[0073] Optionally, after the first substrate and the second substrate are opposed, the method further includes:

[0074] A spacer is arranged between the first substrate and the second substrate.

[0075] The spacer can be a quartz microsphere or a quartz column, and can be arranged at the boundary position of the first substrate and the second substrate.

[0076] S150, the orienting layer is oriented to form a target control pattern.

[0077] Optionally, the orienting of the orienting layer to form the target pattern includes:

[0078] The empty box composed of the first substrate, the second substrate, and the spacer is subjected to ultraviolet orientation, so that the orientation direction of the orienting layer is consistent with the control pattern.

[0079] The control pattern of the orienting layer presents a ring-shaped gradient arrangement or an angular distribution.

[0080] Optionally, the ultraviolet light orientation includes: using a digital micro-mirror projection system, synchronously controlling an exposure pattern and a polarizer angle according to an exposure sequence, and performing ultraviolet exposure processing on a region where the orientation layer is located, so that the orientation layer forms a control pattern.

[0081] S160, forming a ferroelectric liquid crystal layer between the first substrate and the second substrate to form a dynamic edge detection device.

[0082] The ferroelectric liquid crystal layer is oriented according to a target control pattern.

[0083] Specifically, the process of forming the ferroelectric liquid crystal layer between the first substrate and the second substrate includes: filling the ferroelectric liquid crystal in an isotropic state between the first substrate and the second substrate, slowly cooling to a chiral smectic C phase state, and manufacturing a dynamic edge detection device.

[0084] For example, the ferroelectric liquid crystal material selected by the embodiment of the present application is converted from isotropic to chiral smectic A phase at 78℃, and is converted from chiral smectic A phase to chiral smectic C phase at 72℃, so that the cooling process can include using a cooling rate of 0.1℃ / min within a range of ±2℃ of the phase transition temperature, wherein the ferroelectric liquid crystal layer is oriented according to the control pattern.

[0085] Figure 6 A structural schematic diagram of a dynamic edge detection device provided by the embodiment of the present application is shown in Figure 6 The dynamic edge detection device includes an external electric field regulation unit 9, and a laser 1, a target object 2, a first polarizer 3, a first lens 4, a dynamic edge detection device 5 provided by the above embodiment, a second lens 6, a second polarizer 7, and an imaging device 8 arranged in sequence along a common optical axis; the light beam output by the laser 1 is transmitted through the first polarizer 3 and the first lens 4 in sequence after illuminating the target object 2, and is incident from the side of the first substrate of the dynamic edge detection device 5, the dynamic edge detection device 5 performs geometric phase modulation on the incident linearly polarized light beam, and the outgoing light beam is transmitted through the second lens 6 and the second polarizer 7 in sequence and is received by the imaging device 8; the imaging device 8 receives a one-dimensional edge image of the target object 2; the external electric field regulation unit 9 is used to regulate the external electric field environment in which the dynamic edge detection device 5 is located; by changing the polarity of the external electric field, the polarization direction of the outgoing vector light beam is rotated after passing through the dynamic edge detection device 5, and the direction of the one-dimensional edge image of the image is selectively switched.

[0086] Exemplarily, the target object 2 is constituted by a mask plate, the imaging device 8 is a charge coupled device (CCD) camera, and the external field control unit 9 is a signal generator. The light beam output by the laser 1 is processed by the mask plate to obtain the object light. Then, the object light sequentially passes through the first polarizer 3 and the first lens 4 to reach the dynamic edge detection device 5, is transmitted after being modulated by the spiral phase, and sequentially passes through the second lens 6 and the second polarizer 7 to be received by the CCD camera; the signal generator is used to adjust the polarity of the switched external electric field to control the direction of the output edge.

[0087] In specific implementation, the actual situation can be designed. By adjusting the external electric field, the polarization distribution of the emergent vector light field of the dynamic edge detection device 5 can be changed, so that different direction edge images are output after passing through the second polarizer 7. Exemplarily, +5V and -5V voltages can be used as the external electric field.

[0088] The first polarizer 3 is used to realize linearly polarized light incidence, and the second polarizer 7 is used to filter the required polarization component and keep orthogonality with the first polarizer 3. The first lens 4 and the second lens 6 constitute a 4f system; the mask plate is placed on the front focal plane of the first lens 4 to obtain the object light; the dynamic edge detection device 5 is placed on the spectral plane of the 4f system, i.e., the common focal plane of the first lens 4 and the second lens 6, to modulate the incident object light in the frequency domain; and the CCD camera is placed at the back focal plane of the second lens 6 to obtain a clear edge image.

[0089] Exemplarily, Figure 7 An edge detection result diagram of the dynamic edge detection device provided in the embodiment of the application is shown in FIG. 4. Referring to FIG. 4, Figure 7 When the incident light is linearly polarized light of 550 nm, the first column is different bright field images without modulation of the dynamic edge detection device, the second column is vertical edge images obtained under a +5V external voltage environment, and the third column is horizontal edge images obtained under a -5V external voltage environment.

[0090] Exemplarily, Figure 8 A switching response time diagram of the dynamic edge detection device provided in the embodiment of the application is shown in FIG. 5. The switching time between the vertical and horizontal edge image states is defined as the duration when the intensity changes between 10% and 90%. When an alternating square wave signal of 10Vpp and 1 kHz is applied, the response times of the horizontal-to-vertical edge and the reverse process are measured as 53 μs and 60 μs, respectively. Referring to FIG. 5, Figure 8 The dynamic crystal edge detection device still maintains the ultrafast response speed and good stability and reversibility under 2000 cycles.

[0091] It should be noted that the embodiment of the present application only exemplarily shows the dynamic edge detection effect corresponding to the 550nm incident light, and is not a limitation on the working waveband of the dynamic edge detection device provided by the present application. In other embodiments, the device still has applicability, and according to actual needs, a suitable ferroelectric liquid crystal is selected, so that the dynamic edge detection device provided by the embodiment of the present application has different response times.

[0092] The dynamic edge detection device provided by the embodiment of the present application uses the dynamic edge detection device to set the annular gradual arrangement, angular distribution topological spiral layered structure, the spiral can be changed by applying an external electric field to change the liquid crystal molecule director distribution, the equivalent optical axis distribution will have a whole rotation when the polarity is switched, so as to change the diffraction vector light field polarization distribution, and finally realize the fast switching of the one-dimensional edge image of the target object in two orthogonal directions. In the embodiment, under the environment of the positive polarity external electric field, the vertical edge detection of the target object can be realized, and when the external electric field is negative, the horizontal edge detection of the target object can be realized. The dynamic edge detection device can effectively improve the limitations of the conventional optical edge detection device, such as lack of adjustability and limited function.

[0093] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A dynamic edge detection device, characterized by, The device comprises a first substrate, a second substrate and a ferroelectric liquid crystal layer between the first substrate and the second substrate; The first substrate is provided with a first transparent electrode layer on the side facing the second substrate, and the second substrate is provided with a second transparent electrode layer on the side facing the first substrate; The first transparent electrode layer is provided with an orientation layer on the side facing the second substrate, and the control pattern of the orientation layer presents a circularly varying arrangement or an angular distribution; The ferroelectric liquid crystal layer comprises ferroelectric liquid crystal molecules, which form a layered helical structure, the helical axis of the layered helical structure is parallel to the plane of the first substrate, and the arrangement direction of the helical axis presents a circularly varying arrangement or an angular distribution according to the control pattern of the orientation layer; When an external electric field is applied between the first transparent electrode layer and the second transparent electrode layer, which is perpendicular to the first substrate and has a voltage greater than or equal to a threshold voltage, the helical structure of the ferroelectric liquid crystal layer is disentangled; When different voltages are applied between the first transparent electrode layer and the second transparent electrode layer, the dynamic edge detection device realizes different edge detection effects.

2. The dynamic edge detection device of claim 1, wherein, The device further comprises a spacer between the first substrate and the second substrate, which is used to support the first substrate and the second substrate to form a containing space for the ferroelectric liquid crystal layer.

3. A dynamic edge detection device according to claim 2, characterized in that The size of the spacer in the direction perpendicular to the plane of the first substrate is greater than or equal to the pitch of the layered helical structure.

4. The dynamic edge detection device of claim 1, wherein, The ferroelectric liquid crystal layer comprises a chiral smectic C phase ferroelectric liquid crystal, the normal line of the smectic layer of the chiral smectic C phase ferroelectric liquid crystal is always parallel to the plane of the first substrate, and the helical axis of the helical structure always parallel to the plane of the first substrate under no external electric field, and the pitch of the helical axis is smaller than the distance between the first substrate and the second substrate.

5. The dynamic edge detection device of claim 1, wherein, When an external electric field is applied between the first transparent electrode layer and the second transparent electrode layer, which is perpendicular to the first substrate and has a voltage greater than or equal to a threshold voltage, the director of the ferroelectric liquid crystal molecules will rotate to one side of the helical cone surface parallel to a substrate according to the polarity of the electric field; When the polarity of the external electric field is reversed, the director of the ferroelectric liquid crystal molecules will rotate to the corresponding other side.

6. The dynamic edge detection device of claim 1, wherein, The orientation direction of the helical axis presents a circularly varying arrangement or an angular distribution under no external electric field, and the distribution of the equivalent optical axis satisfies α=φ / 2+α0; When an external electric field is applied between the first transparent electrode layer and the second transparent electrode layer, which is perpendicular to the first substrate and has a voltage greater than or equal to a threshold voltage, the director of the disentangled ferroelectric liquid crystal molecules presents a circularly varying arrangement or an angular distribution; When the external electric field is applied, the distribution of the overall optical axis changes, when a positive electric field is applied, the distribution of the equivalent optical axis satisfies α=φ / 2+α0+θ, and when a negative electric field is applied, the distribution of the equivalent optical axis satisfies α=φ / 2+α0-θ; Wherein, φ is the azimuth angle, α0 is the initial angle of the equivalent optical axis, and θ is the tilt angle of the ferroelectric liquid crystal.

7. The dynamic edge detection device of claim 1, wherein, By applying external electric fields with different polarities to the ferroelectric liquid crystal layer, the rotation and transformation of the vector light beam are realized, the linear polarization direction at the same spatial position is rotated synchronously, and a vector light beam with another polarization distribution is formed.

8. A method for producing a dynamic edge detection device, for producing the dynamic edge detection device according to any one of claims 1 to 7, characterized by The preparation method comprises: providing a first substrate and a second substrate; forming a first transparent electrode layer on one side of the first substrate and a second transparent electrode layer on one side of the second substrate; forming an orientation layer on one side of the first substrate; opposing the first substrate and the second substrate; orienting the orientation layer to form a target control pattern; forming a ferroelectric liquid crystal layer between the first substrate and the second substrate to form the dynamic edge detection device; wherein the first transparent electrode layer is located on the side of the first substrate facing the second substrate, the second transparent electrode layer is located on the side of the second substrate facing the first substrate, the orientation layer is located on the side of the first substrate facing the second substrate, the target control pattern of the orientation layer presents a ring-shaped gradient arrangement and an angular distribution, and the ferroelectric liquid crystal layer is oriented according to the target control pattern.

9. The production method according to claim 8, characterized by, After the first substrate and the second substrate are opposed, further comprising: arranging a spacer between the first substrate and the second substrate.

10. A dynamic edge detection apparatus, characterized by, comprising an external electric field regulating unit and a laser, a target object, a first polarizer, a first lens, the dynamic edge detection device of any one of claims 1-7, a second lens, a second polarizer and an imaging device arranged in sequence on a common optical axis; the light beam output by the laser passes through the first polarizer and the first lens in sequence after illuminating the target object, is incident from the side of the first substrate of the dynamic edge detection device, the dynamic edge detection device performs geometric phase modulation on the incident linearly polarized light beam, and the outgoing light beam passes through the second lens and the second polarizer in sequence and is then received by the imaging device; the imaging device receives a one-dimensional edge image of the target object; the external electric field regulating unit is used to regulate the external electric field environment in which the dynamic edge detection device is located; changing the polarity of the external electric field causes the polarization direction of the outgoing vector light beam to rotate after passing through the dynamic edge detection device, and the direction of the one-dimensional edge image of the image is selectively switched.

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