High-Speed Motion Control Method and System Applied to the Phase Modulation Workbench of the LCOS System

Abstract

The present invention discloses a high-speed motion control method applied to a phase modulation workbench of an LCOS system, which includes dividing a large-format processing pattern into several pattern blocks, generating two-dimensional physical coordinates and pattern block numbers corresponding to each pattern block, and sorting the two-dimensional physical coordinate set in the position file in ascending order row by row or column by column; the motion controller uploads the data row by row or column by column to the memory of the motion controller in sequence, and uploads the sub-bitmaps corresponding to the pattern block numbers to the memory of the LCOS board row by row or column by column; the workbench scanning axis triggers a timing pulse signal by position, and simultaneously sends it to the LCOS and the pulsed light source to form a fast pulse scanning exposure. The present invention utilizes the characteristics of high pulse laser energy, short pulse width, and high repetition frequency, and realizes single-frame polarization pattern recording based on multiple pulses. For the precise control of the motion of the workbench, it has achieved the advantages of large exposure area, high efficiency, and good reliability.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal alignment control, and particularly to a high-speed motion control method and system applied to a phase modulation workbench of an LCOS system. Background Art

[0002] The polarization orientation technology based on a liquid crystal spatial modulator is a programmable control device capable of modulating the phase and amplitude of incident light. Single-shot projection orientation can achieve pattern recording of different alignment arrangements of liquid crystals in different selected areas.

[0003] Patent Application No. CN201820881217.1 discloses an optical orientation device for realizing arbitrary distribution by single exposure. It introduces an optical control orientation method using a pixelated electro-optic phase delay device for single exposure. Among them, the phase delay of each pixel of the pixelated electro-optic phase delay device is controlled by the corresponding voltage respectively, and is used to generate an arbitrary pattern distribution of phase delay. However, the problem brought by generating a phase pattern by single exposure is that the data volume is proportional to the size of the image area, which limits the size of the device prepared, and it is also doomed to be unable to generate a high-precision and high-resolution optical orientation pattern.

[0004] The foreign company beam provides a device and method for optical orientation using continuous laser irradiation of an LCOS phase modulation device (De Sio L, Roberts D E, Liao Z, et al. Digital polarization holography advancing geometrical phase optics[J]. Optics express, 2016, 24(16): 18297-18306.). They use low-energy continuous laser for exposure. Considering the information volume of the image, exposure uniformity, material heat capacity, heat diffusion and other properties, it takes dozens of seconds to dozens of minutes for single-field exposure, and the exposure area is limited by the image information, and it is impossible to perform optical orientation on a large-area image area.

[0005] Therefore, there is an urgent need for a new device for outputting a polarization pattern in the liquid crystal display field and a workbench motion control system matching the device to achieve efficient, accurate and large-area optical orientation. Summary of the Invention

[0006] In order to solve the problems of the prior art, the present invention discloses a high-speed motion control method applied to a phase modulation workbench of an LCOS system. The high-speed motion control method includes the following steps:

[0007] S1. Process the large-area processing graphics to generate corresponding grayscale graphics;

[0008] S2. Divide the grayscale graphic into several grayscale graphic blocks, generate the two-dimensional physical coordinates and graphic block numbers corresponding to each grayscale graphic block, record the two-dimensional physical coordinates and graphic block numbers in a position file, and record the graphic block numbers and the file paths of the graphic block numbers in a sequence file;

[0009] S3. Sort the two-dimensional physical coordinates in the position file in ascending order by row or column, and save the sorted two-dimensional physical coordinates and their corresponding graphic block numbers as a scan file;

[0010] S4. The motion controller reads the scan file in the position file, and uploads the data of the two-dimensional physical coordinates in the scan file to the motion controller memory row by row or column by column in sequence;

[0011] S5. According to the graphic block numbers corresponding to the data of the two-dimensional physical coordinates in the scan file, find the storage path where the grayscale graphic block file is located, and upload the grayscale graphic block file to the LCOS board memory row by row or column by column in sequence;

[0012] S6. The motion controller controls the two-dimensional workbench to perform non-stop scanning motion in the row or column as described in step S4;

[0013] S7. When the workbench passes through a preset position during the scanning motion, the controller triggers a timing pulse signal and sends it to the LCOS and the pulsed light source at the same time to form a fast pulsed scanning exposure.

[0014] As a further improvement of the embodiment of the present invention, the data processing in S1 specifically includes pre-correcting the grayscale values of the large-format processing graphics to make the grayscale values of the file match the phase modulation of the LCOS.

[0015] As a further improvement of the embodiment of the present invention, the splitting operation in step S2 specifically includes splitting the large-format processing graphic into M*N graphic blocks according to a size not greater than the field-of-view resolution.

[0016] As a further improvement of the embodiment of the present invention, the size of the field-of-view resolution is the LCOS pixel width * pixel height.

[0017] As a further improvement of the embodiment of the present invention, a parallel processing method of the memory of the controller and the memory of the LCOS board is adopted; the number of blocks divided from the memory of the controller and the memory of the LCOS board is M, M≥2, and the number of points that each block of memory can store is N;

[0018] When uploading data for the first time, upload M*N two-dimensional physical coordinate point data to the memory in the controller; M*N graphic blocks are uploaded to the LCOS board memory;

[0019] The number of blocks M divided from the controller memory and the LCOS board memory is set manually or automatically.

[0020] As a further improvement of the embodiment of the present invention, the specific steps of the parallel processing mode of the controller memory and the LCOS board memory in the high-speed motion control method are as follows:

[0021] During operation, first execute the data in the first block of memory. After the data in the first block of memory is executed, notify the control software to update the data in the first block of memory. At the same time, the workbench does not stop working and continues to execute the data in the next block of memory. After the data in the last block of memory is executed, notify the control software to update the data in the last block of memory. At the same time, the workbench does not stop working and starts to execute the data in the first block of memory again, and so on in a loop.

[0022] As a further improvement of the embodiment of the present invention, the pulse signal in step S7 is a switch signal, which is used to realize the switching on and off of the pulsed light source and the display and closing of the LCOS pattern.

[0023] As a further improvement of the embodiment of the present invention, according to the scanning file, only one complete line-by-line or column-by-column scanning exposure needs to be performed to complete a fast scanning exposure task with multiple orientations.

[0024] On the other hand, the present invention also discloses a high-speed motion control system applied to the LCOS system phase modulation workbench. The high-speed motion control system includes a workbench, a motion controller, a motor drive circuit, and a motor;

[0025] The motion controller is used to receive the two-dimensional physical coordinate signal of the workbench and send an exposure switch command to the LCOS system phase modulation device;

[0026] The motor drive circuit is used to issue a drive voltage control signal;

[0027] The motor is used to be controlled by the motor drive circuit to drive the workbench;

[0028] The workbench includes a scanning axis and a position feedback module. The position feedback module is used to detect the moving position of the scanning axis in real time.

[0029] As a further improvement of the embodiment of the present invention, the high-speed motion control system further includes a detection device, which is used to monitor the motion state information of the motor in real time and send the motion position and speed of the motor to the motion controller.

[0030] As a further improvement of the embodiment of the present invention, the workbench carries the light polarization-sensitive material to move in a two-dimensional plane to further realize the polarization light field splicing or the interconnection between different polarization light fields.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The low-speed motion control system applied to the phase modulation workbench of the LCOS system in the present invention realizes precise control of the motion of the workbench, and further uses the high-speed exposure patterning liquid crystal photo-alignment method with pulsed laser illumination to real-time control the phase change of a single exposure area, achieving high-precision and high-resolution exposure;

[0033] 2. The present invention utilizes the characteristics of high energy, short pulse width and high repetition frequency of pulsed laser, and realizes single-frame polarization pattern recording based on multiple pulses, achieving the advantages of large exposure area, high efficiency and good reliability;

[0034] 3. The present invention uses a high-precision workbench to precisely control the sample to move in a two-dimensional plane, providing favorable conditions for realizing large-format writing;

[0035] 4. Since the light energy is not concentrated in the present invention, it is proposed to eliminate the stitching between each optically controlled alignment field by controlling the relationship between the single field size and the single translation distance, improving the resolution;

[0036] 5. The present invention has the advantages of high-precision arbitrary controllability of the single-exposure polarization pattern, large-area writing and high efficiency, which is of great significance for the design and manufacture of large-size, high-precision and multi-functional liquid crystal optical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 is a flowchart of a high-speed motion control method applied to the phase modulation workbench of the LCOS system provided by an embodiment of the present invention;

[0039] Figure 2 is a schematic structural diagram of a high-speed motion control system applied to the phase modulation workbench of the LCOS system provided by an embodiment of the present invention;

[0040] Figure 3 is a schematic structural diagram of a high-speed exposure patterning liquid crystal photo-alignment device provided by an embodiment of the present invention;

[0041] Figure 4 is a schematic diagram of the selection of the pulsed laser frequency and the refresh frequency of the phase modulation device of the high-speed exposure patterning liquid crystal photo-alignment device in an embodiment of the present invention;

[0042] Figure 5 It is a schematic diagram of the peak absorption characteristics of a light polarization-sensitive material adopted in an embodiment of the present invention. Specific embodiments

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] An embodiment of the present invention discloses a high-speed motion control method applied to a phase modulation workbench of an LCOS system, as Figure 1 shown. The high-speed motion control method includes the following steps:

[0045] S1. Perform data processing on a large-format processing graphic to generate a corresponding grayscale graphic; the data processing specifically includes pre-correcting the grayscale values of the large-format processing graphic to match the phase regulation of the LCOS.

[0046] S2. Divide the grayscale graphic into several grayscale graphic blocks, generate two-dimensional physical coordinates and graphic block numbers corresponding to each grayscale graphic block, record the two-dimensional physical coordinates and graphic block numbers in a position file, and record the graphic block numbers and the file paths of the graphic block numbers in a sequence file; the division operation in step S2 specifically includes dividing the large-format processing graphic into M*N graphic blocks according to a size not greater than the field resolution; the size of the field resolution is the LOCS pixel width * pixel height.

[0047] Specifically, any one selected from 1024*768, 1920*1080, and 1920*1152.

[0048] S3. Sort the two-dimensional physical coordinates in the position file in ascending order by row or column, and save the sorted two-dimensional physical coordinates and their corresponding graphic block numbers as a scan file.

[0049] S4. The motion controller reads the scan file in the position file and uploads the data of the two-dimensional physical coordinates in the scan file to the motion controller memory row by row or column by column.

[0050] S5. According to the graphic block numbers corresponding to the data of the two-dimensional physical coordinates in the scan file, find the storage path where the grayscale graphic block file is located, and upload the grayscale graphic block file to the LCOS board memory row by row or column by column.

[0051] S6. The motion controller controls the two-dimensional workbench to perform a non-stop scanning motion along the row or column described in step S4.

[0052] S7. When the workbench passes through a preset position during the scanning motion, the controller triggers a timing pulse signal and sends it to the LCOS and the pulsed light source simultaneously to form a fast pulsed scanning exposure.

[0053] In the embodiment of the present invention, a parallel processing method of the memory of the controller and the memory of the LCOS board is adopted; the number of blocks divided from the memory of the controller and the memory of the LCOS board is M, M≥2, and the number of points that each block of memory can store is N; when uploading data for the first time, M*N two-dimensional physical coordinate point data are uploaded to the memory in the controller; M*N graphic blocks are uploaded to the memory in the LCOS board; the number of blocks M divided from the memory of the controller and the memory of the LCOS board is set manually or automatically.

[0054] Among them, the specific steps of the parallel processing method of the memory of the controller and the memory of the LCOS board in the high-speed motion control method are as follows:

[0055] During operation, first execute the data in the first block of memory. When the data in the first block of memory is executed, notify the control software to update the data in the first block of memory. At the same time, the workbench does not stop working and continues to execute the data in the next block of memory; when the data in the last block of memory is executed, notify the control software to update the data in the last block of memory. At the same time, the workbench does not stop working and starts to execute the data in the first block of memory again, and loops in turn.

[0056] On the other hand, the present invention also discloses a high-speed motion control system applied to a phase modulation workbench of an LCOS system, as Figure 2 shown. The high-speed motion control system includes a workbench, a motion controller, a motor drive circuit, and a motor.

[0057] The motion controller is used to receive the two-dimensional physical coordinate signal of the workbench and send an exposure switch instruction to the LCOS system phase modulation device.

[0058] The motor drive circuit is used to issue a drive voltage control signal.

[0059] The motor is used to drive the workbench under the control of the motor drive circuit.

[0060] The workbench includes a scanning axis and a position feedback module, and the position feedback module is used to detect the moving position of the scanning axis in real time.

[0061] Furthermore, the high-speed motion control system further includes a detection device, which is used to monitor the motion state information of the motor in real time and send the motion position and speed of the motor to the motion controller.

[0062] The workbench carries the light polarization-sensitive material and moves in a two-dimensional plane to further achieve the splicing of polarized light fields or the interconnection between different polarized light fields.

[0063] The high-speed motion control system of the above workbench is applied to the phase modulation process of the LCOS system; the phase modulation process of the LCOS system is realized by the following high-speed exposure patterning liquid crystal photo-alignment device, as Figure 3 shown, including a lighting component, a polarization pattern generation component, an imaging detection component, a focal length servo system, and a motion control component connected in sequence;

[0064] The lighting component is used to provide a light source for continuous stroboscopic exposure and to achieve a single-polarization collimated uniform surface light spot;

[0065] The polarization pattern generation component includes a quarter-wave plate and a phase modulator connected in sequence, and is used to output a pixelated programmable polarization pattern onto the workpiece; the phase modulator is connected to the imaging detection component; the phase modulation device is a liquid crystal phase modulation device, which is used to load different phases for each pixel;

[0066] The imaging detection component is used to detect the imaging of the generated pattern; the focal length servo system includes a normally-on light source insensitive to the light polarization-sensitive material and a vertical direction correction component, which is used to correct the defocus phenomenon caused by the motion;

[0067] The motion control component is used to adjust the spatial position of the workbench carrying the light polarization-sensitive material to achieve the splicing of light fields.

[0068] In the embodiment of the present invention, the lighting component is a pulsed light source, specifically, a pulsed laser; in other alternative embodiments, the lighting component can also be a continuous light source with a controllable light shielding system; the pulse width of the pulsed laser generated by the lighting component is in the range of picoseconds to seconds, and the wavelength of the pulsed laser is in the range of 340 nm to 600 nm; the energy per unit area of the pulsed light source is higher than the threshold energy of the light polarization-sensitive material on the liquid crystal substrate and lower than the damage threshold of the phase modulation device.

[0069] In other alternative embodiments, the pulsed light source can also be generated by a continuous laser plus a mechanical or optoelectronic light shielding plate, or a pulsed LED or a continuous LED plus a controllable light shielding system.

[0070] Preferably, the pulse width of the pulsed laser is less than or equal to the image holding time of the phase modulation device. When an image of the phase modulation device is held, at least one pulsed laser peak irradiates the phase modulation device.

[0071] In the embodiment of the present invention, the light emitted by the laser has a wavelength of 442 nm, a single pulse energy of 0.2 mJ, a pulse width of 10 ns, is pulsed light and S polarized. After being collimated and adjusted by the beam expander system and then passing through the polarizer, a collimated and uniform light spot with a spot diameter of 2 cm, a divergence angle less than 10 mrad, S polarization, and a light intensity uniformity better than 80% is formed.

[0072] Specifically, in the embodiment of the present invention, the illumination component includes a collimation component and a polarizer; the collimation component and the polarizer form a collimation and polarization component.

[0073] The collimation component is used to adjust a line light source or a point light source into a parallel plane light source and output it to the polarization image generation component;

[0074] The polarizer is used to generate a single polarized light. The polarizer is connected to the collimation component and is used to control the initial polarization direction of the light and generate a plane light source with an arbitrary polarization direction within the range of 0 - 179 degrees.

[0075] In the embodiment of the present invention, the phase modulation device is a pixel - type phase retarder with adjustable phase difference; and reflects the polarized plane light source into a light spot containing different polarization information and transmits it to the beam splitting component; the phase modulation device has a phase delay modulation of the pulsed light source greater than 2π; the phase modulation accuracy of a single gray level controlled by a computer program is better than 0.01π to achieve arbitrary phase delay modulation within one period; the phase delay amount drift of the phase modulation device is less than 0.005π.

[0076] Furthermore, the imaging detection component further includes a micro - imaging component;

[0077] The micro - imaging component is used to micro - image the polarization pattern output by the polarization pattern generation component and write it into the light polarization - sensitive material;

[0078] The micro - imaging component includes an imaging objective lens group. The main axis direction of the optical path of the imaging objective lens group is perpendicular to the workbench. The motor drives the imaging objective lens group to move up and down in the vertical direction to form a focal plane on the workbench.

[0079] In the embodiment of the present invention, the workbench is arranged below the imaging objective lens group and has a two - dimensional motion track, which is used to carry the light polarization - sensitive material and drive the light polarization - sensitive material to move in a two - dimensional plane under the drive of the motion control component, so that the surface of the light polarization - sensitive material always remains in the focal plane of the imaging objective lens group;

[0080] The motion control component is connected to the micro - imaging component and is used to splice the micro - imaged polarization pattern light field.

[0081] The imaging detection component includes a first beam splitter, a tube lens, an imaging objective lens group, a first lens, and a first imaging CCD connected in sequence;

[0082] The front focal plane of the imaging objective lens group is located at the rear focal plane of the barrel lens; the imaging plane of the first imaging CCD is located at the front focal plane of the first lens; the rear focal plane of the first lens is located at the front focal plane of the barrel lens.

[0083] As a further improvement of the embodiment of the present invention, the focal length servo system includes a detection light source, a second lens, a second beam splitter, an imaging objective lens group, a second imaging CCD, and a motor connected in sequence;

[0084] The detection light source is located at the front focal plane of the second lens; the second beam splitter is located at the rear focal plane of the second lens; the imaging plane of the second imaging CCD is located at the front focal plane of the second lens; the motor drives the imaging objective lens group;

[0085] The first imaging CCD receives the reflected image projected onto the surface of the light polarization sensitive material, and the first imaging CCD and the phase modulator form a conjugate image.

[0086] In the embodiment of the present invention, a quarter-wave plate is arranged between the phase modulator and the imaging detection component; the phase modulator is a liquid crystal spatial light modulator, which is a pixel-type phase retarder with adjustable phase difference δ; the polarization rotation direction is δ / 2; the incident light polarization direction, the crystal axis direction of the phase modulation device, and the crystal axis direction of the quarter-wave plate form an angle of 0, 45, and 90 degrees.

[0087] In other implementable ways, the polarization pattern generation component includes a first quarter-wave plate, a phase modulation device, and a second quarter-wave plate connected in sequence; the number of quarter-wave plates may not be unique.

[0088] Among them, the long axis direction of the first quarter-wave plate, the crystal axis direction of the phase modulation device, and the crystal axis direction of the first quarter-wave plate form an angle of 0, 45, and 90 degrees.

[0089] In the embodiment of the present invention, the motion control component further includes a controller, a motor driving device, and a motor detection device. The controller is used to convert the collected optical path data into control signals and send them to each execution component;

[0090] The controller includes a motion control module, and the motion control module includes a workbench motion control unit;

[0091] The motor driving device is used to drive the motor to drive the workbench to move, and the motor detection device is used to monitor the motion of the motor in real time and send the motion position and speed of the motor to the motion control module;

[0092] The workbench motion control unit is used to control the movement of the light polarization sensitive material in a two-dimensional plane to achieve polarization light field splicing or interconnection between different polarization light fields through the pattern splicing component.

[0093] In some embodiments, to solve the problem of generating arbitrary polarization orientations, a polarization pattern generation component includes a quarter-wave plate and a phase modulator connected in sequence, which is used to generate a pattern with an arbitrary polarization distribution; the phase modulation device regulates the polarization level of each pixel through voltage, and each pixel determines the magnitude of the voltage through different gray-scale information, thereby realizing the regulation of polarization information by the gray-scale image. The gray-scale image can be written in real time or pre-loaded; the phase modulation device can be, but is not limited to, an ultra-high-speed liquid crystal spatial light modulator, which can be used as a real-time programmable phase plate to perform wavefront correction on linearly polarized light, thereby realizing pixelized control of the polarization pattern. The resolution of the original polarization light field is determined by the pixel size of the liquid crystal spatial light modulator.

[0094] The specific process of forming the polarization pattern based on the phase modulation device is as follows: The fast-axis directions of the first quarter-wave plate and the second quarter-wave plate are orthogonal, and are respectively at an angle of 45° with the main axis direction of the liquid crystal arrangement of the phase modulator. After the collimated light spot passes through the first quarter-wave plate, it is incident at an angle of 3° with the normal of the phase modulation device, and the phase modulation device is evenly irradiated. In the embodiment, the phase modulation device used is an LCOS device, with a working frequency of 50 Hz to 400 Hz, a pulsed laser damage threshold greater than 300 mJ / cm 2 , 10 ns, the number of pixels is 1920 * 1080, the size of a single pixel is 8 microns, the size of the entire phase modulation device is 1.54 cm * 0.86 cm, the phase modulation amount for 442 nm is greater than 2π, and the phase modulation accuracy is better than 0.03π.

[0095] The beam splitting component is respectively connected to the micro-imaging component and the imaging detection component, and is used to filter light in a specified band and enter the micro-imaging component and the imaging detection component respectively;

[0096] The motion control component further includes a pattern splicing component, and the pattern splicing component is used to splice the micro-reduced polarization pattern light field.

[0097] The control logic in the embodiments of the present invention is specifically as follows: The control software in the industrial control computer transmits the position data to the motion control module, and the motion control module converts the received data into a control signal and sends it to the motor driver. The motor driver performs motion control on the motor according to the received control signal; the detection device is responsible for monitoring the motion of the motor in real time, and sending the motion position and speed of the motor to the motion control module; the motion control module feeds back the current position and speed of the workbench to the software.

[0098] The phase modulator LCOS in the optical system is connected to the industrial control computer through a data transmission line, so that the control software can transmit phase map data to the LCOS. The motion control card is connected to the laser through a trigger line and controls the light output of the laser by sending pulse signals.

[0099] Correspondingly, a high-speed exposure patterned liquid crystal photo-alignment method, the method comprising the following steps:

[0100] S1. A line light source or a point light source emitted by a light source is adjusted by a polarization collimation device into a collimated polarized plane light source;

[0101] S2. A phase modulation device of a polarization pattern generation component loads a corresponding phase according to pattern information, reflects the polarized plane light source into light spots containing different polarization information, and transmits the light spots to a beam splitting component;

[0102] S3. The beam splitting component conducts the light rays with polarization information to an imaging detection component;

[0103] S4. A servo focusing system adjusts the distance between an imaging objective lens group and a light polarization sensitive material surface, so that the focal plane of the imaging objective lens group always remains on the light polarization sensitive material surface;

[0104] S5. A single light-controlled orientation is recorded on a light polarization sensitive material;

[0105] S6. The workbench carrying the light polarization sensitive material is moved to the next specified position for the next pattern light field recording.

[0106] In an embodiment of the present invention, after step S3, the following steps are further included: A micro-imaging component forms a fixed micro-imaging magnification through the ratio of the focal length of a tube lens to that of the imaging objective lens group, and micro-images the polarization pattern output by the phase modulation device, and then outputs a polarization pattern light field.

[0107] Further, after the step S6 of the high-speed exposure patterned liquid crystal photo-alignment method, the following is further included:

[0108] S7. Each orientation unit is spliced together to form a large-area polarized light pattern photo-alignment structure on the light polarization sensitive material.

[0109] Wherein, step S2 adjusts the polarization information of each pixel point in each sub-image through a grayscale image, specifically including that the phase modulation device regulates the polarization level of each pixel point through voltage, and each pixel point determines the magnitude of the voltage through different grayscale information, so as to realize the regulation of the polarization information by the grayscale image;

[0110] The grayscale image is written in real time or pre-loaded;

[0111] The phase modulation device is a high-speed liquid crystal phase modulation device, which performs wavefront correction on linearly polarized light as a real-time programmable phase plate, so as to realize pixelized control of the polarization pattern.

[0112] Preferably, the wavelength of the light emitted by the detection light source is a value outside the polarization photosensitive absorption wavelength region; the wavelength of the light emitted by the detection light source in step S4 is any value between 550 nm and 650 nm;

[0113] The second lens reflects the light spot projected onto the surface of the light polarization-sensitive material into the second imaging CCD. The Z-axis servo focusing position is mapped through the diameter of the light spot, and the up and down height of the Z-axis lens is adjusted, so that the diameter of the light spot in the second imaging CCD can always be maintained at R, and the size of the light spot projected onto the surface of the light polarization-sensitive material is detected by the second imaging CCD to determine whether the surface of the light polarization-sensitive material is in the focal plane of the objective lens.

[0114] In the embodiment of the present invention, after the single polarization pattern is recorded on the light polarization-sensitive material, the workbench carrying the light polarization-sensitive material is moved to the next specified position for the next orientation, which is specifically realized through the following steps:

[0115] The controller transmits the position data to the motion control module, the motion control module converts the received data into a control signal and sends it to the motor driver, the motor driver performs motion control on the motor according to the received control signal, and the detection device is responsible for monitoring the motion of the motor in real time and sending the motion position and speed of the motor to the motion control module; then the motion control module feeds back the current position and speed of the workbench to the controller.

[0116] After the single light control orientation is recorded on the light polarization-sensitive material, the moving distance of the workbench carrying the light polarization-sensitive material to the next specified position by the motion control module is the size of the single orientation unit, and the moving mode is sequential row-by-row moving scanning; specifically, the time of each moving step is an integer multiple of the pulse width of the pulsed laser, and the same pattern light field can be exposed by multiple laser pulses.

[0117] Among them, the relationship between the pulsed laser frequency and the refresh frequency of the phase modulation device is as Figure 4 shown. For the pulsed laser, its pulsed laser frequency corresponds to the frequency of the phase modulation device, and the pulse width is less than or equal to the image holding time of the phase modulation device, that is, when an image of the phase modulation device is held, there is a pulsed laser peak irradiating on the phase modulation device.

[0118] During the image holding time of the phase modulation device, multiple pulsed laser peaks can also irradiate on the receiving window of the phase modulation device, which can enhance the single exposure energy.

[0119] The wavelength absorption characteristics of the light control orientation material used in this embodiment are as Figure 5 shown; the material used is an azo-based light orientation material, corresponding to Figure 5For the middle material 3, a good photo-controlled alignment effect can be obtained when illuminated with a laser with a wavelength of 442 nm. Pulse laser light sources with different wavelengths can also be selected according to the photo-alignment material, or corresponding photo-alignment materials can be selected according to pulse laser light sources with different wavelengths. The microscale component uses a 20x microscale objective lens, that is, the spot area is reduced by 400 times and the energy density is increased by 400 times. After microscaling, the size of a single pixel is only 0.4 microns, and high-precision pattern information exposure direct writing can be achieved. At this time, the photosensitivity of the photo-alignment material is 50 mJ / cm 2 , which is higher than the photo-controlled alignment energy threshold and lower than its damage threshold.

[0120] It should be noted that the "stroboscopic" defined in the present invention means emitting light and / or quenching according to a certain preset frequency.

[0121] Compared with the prior art, the present invention has the following beneficial effects:

[0122] 1. The low-speed motion control system applied to the phase modulation workbench of the LCOS system involved in the present invention realizes precise control of the motion of the workbench, and further uses the high-speed exposure patterning liquid crystal photo-alignment method with pulsed laser illumination to real-time control the phase change of a single exposure area, achieving high-precision and high-resolution exposure;

[0123] 2. The present invention utilizes the characteristics of high energy, short pulse width, and high repetition frequency of pulsed lasers, and realizes single-frame polarization pattern recording based on multiple pulses, achieving the advantages of large exposure area, high efficiency, and good reliability;

[0124] 3. The present invention uses a high-precision workbench to accurately control the sample to move in a two-dimensional plane, providing favorable conditions for realizing large-format writing;

[0125] 4. Since the light energy is not concentrated in the present invention, it is proposed to eliminate the seams between each photo-controlled alignment field of view by controlling the relationship between the single field of view size and the single translation distance, improving the resolution;

[0126] 5. The present invention has the advantages of high-precision arbitrary controllability of the polarization pattern in a single exposure, large-area writing, and high efficiency, which is of great significance for the design and manufacture of large-size, high-precision, and multifunctional liquid crystal optical devices.

[0127] All of the above optional technical solutions can be combined arbitrarily to form optional embodiments of the present invention, which will not be elaborated one by one here.

[0128] It should be noted that when the high-speed motion control system for the LCOS system phase modulation workbench provided in the above embodiment executes a high-speed motion control method for the LCOS system phase modulation workbench, only the division of the above functional modules is used for illustration. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the system is divided into different functional modules to complete all or part of the functions described above. In addition, the high-speed motion control system for the LCOS system phase modulation workbench and the high-speed motion control method embodiment provided in the above embodiment belong to the same concept. For the specific implementation process, please refer to the method embodiment and will not be elaborated here.

[0129] Those of ordinary skill in the art can understand that all or part of the steps to implement the above embodiments can be completed by hardware or by a program instructing relevant hardware. The program can be stored in a computer-readable storage medium. The storage medium mentioned above can be a read-only memory, a magnetic disk, an optical disk, etc.

[0130] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-speed motion control method applied to the phase modulation workbench of an LCOS system, characterized in that, the high-speed motion control method includes the following steps: S1. Process the data of the large-format processing graphics to generate corresponding grayscale graphics; S2. Divide the grayscale graphics into several grayscale graphic blocks, generate two-dimensional physical coordinates and graphic block numbers corresponding to each grayscale graphic block, record the two-dimensional physical coordinates and graphic block numbers in a position file, and record the graphic block numbers and the file paths of the graphic block numbers in a sequence file; S3. Sort the two-dimensional physical coordinates in the position file in ascending order by row or column, and save the sorted two-dimensional physical coordinates and their corresponding graphic block numbers as a scan file; S4. The motion controller reads the scan file in the position file, and uploads the data of the two-dimensional physical coordinates in the scan file to the motion controller memory row by row or column by column in sequence; S5. According to the graphic block numbers corresponding to the data of the two-dimensional physical coordinates in the scan file, find the storage path where the grayscale graphic block file is located, and upload the grayscale graphic blocks to the LCOS board memory row by row or column by column in sequence; S6. The motion controller controls the two-dimensional workbench to perform non-stop scanning motion in the row or column described in step S4; S7. When the workbench passes through a preset position during the scanning motion, the controller triggers a timing pulse signal and sends it to the LCOS and the pulsed light source at the same time to form a fast pulse scanning exposure.

2. The high-speed motion control method applied to the phase modulation workbench of an LCOS system according to claim 1, characterized in that, the data processing in S1 specifically includes pre-correcting the grayscale values of the large-format processing graphics to make the grayscale values of the file match the phase regulation of the LCOS.

3. The high-speed motion control method applied to the phase modulation workbench of an LCOS system according to claim 1, characterized in that, the splitting operation in step S2 specifically includes splitting the large-format processing graphics into M*N graphic blocks according to a size not greater than the field resolution.

4. The high-speed motion control method applied to the phase modulation workbench of an LCOS system according to claim 3, characterized in that, the size of the field resolution is the LOCS pixel width * pixel height.

5. The high-speed motion control method applied to the phase modulation under an LCOS system according to claim 1, characterized in that, the high-speed motion control method adopts a parallel processing method of the memory of the controller and the memory of the LCOS board; the number of blocks divided from the memory of the controller and the memory of the LCOS board is M, M≥2, and the number of points that each block of memory can store is N; When uploading data for the first time, upload M*N two-dimensional physical coordinate point data in the memory of the controller; M*N graphic blocks are uploaded in the LCOS board memory; The number of blocks M divided from the controller memory and the LCOS board memory is set manually or automatically.

6. The high-speed motion control method applied to the phase modulation workbench of an LCOS system according to claim 5, characterized in that, The specific steps of the parallel processing method for the controller memory and the LCOS board memory are as follows: During operation, first execute the data in the first memory block. After the data in the first memory block is executed, notify the control software to update the data in the first memory block. At the same time, the workbench does not stop working and continues to execute the data in the next memory block. After the data in the last memory block is executed, notify the control software to update the data in the last memory block. At the same time, the workbench does not stop working and starts to execute the data in the first memory block again, and so on in a loop.

7. The high-speed motion control method applied to the lower phase modulation of the LCOS system according to claim 1, characterized in that, the pulse signal in the step S7 is a switch signal, which is used to realize the switching on and off of the pulsed light source and the display and closing of the LCOS pattern.

8. The high-speed motion control method applied to the lower phase modulation of the LCOS system according to claim 1, characterized in that, According to the scanning file in the step S3, only one complete row-by-row or column-by-column scanning exposure needs to be performed to complete a fast scanning exposure task with multiple orientations at one time.

9. A high-speed motion control system applied to the phase modulation workbench of the LCOS system, characterized in that, for the method according to any one of claims 1-8, the high-speed motion control system includes a workbench, a motion controller, a motor drive circuit and a motor; the motion controller is used to receive the two-dimensional physical coordinate signal of the workbench and send an exposure switch command to the phase modulation device of the LCOS system; the motor drive circuit is used to send a drive voltage control signal; the motor is used to be controlled by the motor drive circuit to drive the workbench; the workbench includes a scanning axis and a position feedback module, and the position feedback module is used to detect the moving position of the scanning axis in real time.

10. The high-speed motion control system applied to the phase modulation workbench of the LCOS system according to claim 9, characterized in that, the high-speed motion control system further includes a detection device, which is used to monitor the motion state information of the motor in real time and send the motion position and speed of the motor to the motion controller; the workbench carries the light polarization sensitive material to move in a two-dimensional plane to further realize the polarization light field splicing or the interconnection between different polarization light fields.

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