Low-speed motion control method and system applied to LCOS system phase modulation workbench

Abstract

The present invention discloses a low-speed motion control method applied to a phase modulation workbench of an LCOS system, comprising: processing data of a large-format processing graphic and dividing it into a plurality of graphic blocks, a motion controller controlling the workbench to move to a designated position corresponding to a two-dimensional physical coordinate; uploading the graphic block file to the memory of the LCOS board card and displaying it on the LCOS panel; the motion controller controlling the pulse light source switch to form an exposure; the workbench moves to a designated position corresponding to the next two-dimensional physical coordinate until all the two-dimensional physical coordinate points of the entire large-format processing graphic are executed. The present invention utilizes the characteristics of large pulse laser energy, short pulse width, and high repetition frequency, realizes single-frame polarization pattern recording based on a single pulse, and accurately controls the movement of the workbench, achieving 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 orientation arrangement control, and in particular to a low-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 liquid crystal spatial modulator is a programmable control device that can modulate the phase and amplitude of incident light. A single projection orientation can realize pattern recording of different orientation arrangements of liquid crystals in different selected areas.

[0003] Patent application No. CN201820881217.1 discloses a light-orientation device that achieves arbitrary distribution in a single exposure. It introduces a light-controlled orientation method that uses a pixelated electrically-controlled phase delay device for single exposure, wherein the phase delay of each pixel of the pixelated electrically-controlled phase delay device is controlled by a corresponding voltage to generate a phase delay with arbitrary graphic distribution. However, the problem with generating a phase pattern through a single exposure is that the amount of data is proportional to the format size, which limits the format size of the prepared device and is doomed to be unable to produce high-precision and high-resolution light-orientation patterns.

[0004] A foreign company, Beam, has provided a device and method for photo-orientation using continuous laser irradiation of LCOS phase modulation devices (De Sio L, Roberts DE, Liao Z, et al. Digital polarization holography advancing geometrical phase optics [J]. Optics express, 2016, 24 (16): 18297-18306.). They used low-energy continuous laser for exposure. Considering the amount of information in the image, exposure uniformity, and the thermal capacity and thermal diffusion properties of the material, it takes tens of seconds to tens of minutes to expose a single field of view. In addition, the exposure format is limited by the image information, and it is impossible to perform photo-orientation on a large area.

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

[0006] In order to solve the problems of the prior art, on the one hand, an embodiment of the present invention discloses a low-speed motion control method applied to a phase modulation workbench of an LCOS system, and the low-speed motion control method comprises the following steps:

[0007] S1, processing the large-format processed graphics to generate corresponding grayscale graphics;

[0008] S2, dividing the grayscale graphic into a plurality of grayscale graphic blocks, generating a two-dimensional physical coordinate and a graphic block number corresponding to each grayscale graphic block, and recording the two-dimensional physical coordinate and the graphic block number into a position file, and recording the graphic block number and the file path of the graphic block number into a sequence file;

[0009] S3, the motion controller reads the two-dimensional physical coordinates in the position file, and controls the workbench to move to a specified position corresponding to the two-dimensional physical coordinates;

[0010] S4, according to the graphic block number corresponding to the two-dimensional physical coordinate, find the file path corresponding to the graphic block number in the sequence file and obtain the grayscale graphic block file;

[0011] S5, uploading the grayscale graphic block file to the LCOS board memory and displaying the grayscale graphic block on the LCOS panel;

[0012] S6, the motion controller controls the pulse light source switch to form one exposure;

[0013] S7, the workbench moves to the designated position corresponding to the next two-dimensional physical coordinate, and the operations of S4-S6 are repeated until the two-dimensional physical coordinate points of the entire large-format processing graphic are completed.

[0014] As a further improvement of the implementation mode of the present invention, the data processing in S1 specifically includes pre-correcting the grayscale value of the large-format processed graphics so that the grayscale value of the file matches the phase regulation of the LCOS.

[0015] As a further improvement of the embodiment of the present invention, the segmentation operation in step S1 specifically includes segmenting the large-format processed graphics into M*N graphic blocks according to a size not greater than the field of view resolution.

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

[0017] As a further improvement of an implementation mode of the present invention, the two-dimensional movement mode of the workbench in S7 moving to the designated position corresponding to the next two-dimensional physical coordinate is consistent with the arrangement order of the two-dimensional physical coordinate points in the position file. When the two-dimensional physical coordinate points in the position file are arranged row by row, the moving workbench moves point by point in row; when the two-dimensional physical coordinate points are arranged column by column, the moving workbench moves point by point in column; when the two-dimensional physical coordinate points are arranged randomly, the moving workbench moves randomly.

[0018] As a further improvement of the implementation mode of the present invention, the low-speed motion control method adopts parallel processing of the controller memory and the LCOS board memory; the number of storage points of the controller memory and the LCOS board memory are both N; 2*N two-dimensional physical coordinate data are uploaded to the controller memory; 2*N graphic block number data are uploaded to the LCOS board memory.

[0019] As a further improvement of the implementation mode of the present invention, the specific steps of the parallel processing mode of the controller memory and the LCOS board memory in the low-speed motion control method are as follows:

[0020] When working, the data in the first block of memory is executed first. When the data in the first block of memory is executed, the instruction is sent to the controller 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 second block of memory; when the data in the second block of memory is executed, the instruction is sent to the controller to update the data in the second block of memory. At the same time, the workbench does not stop working and continues to execute the data in the first block of memory, and the cycle is repeated.

[0021] On the other hand, an embodiment of the present invention discloses a low-speed motion control system applied to a phase modulation workbench of an LCOS system, wherein the low-speed motion control system includes a workbench, a motion controller, a motor drive circuit, and a motor;

[0022] 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;

[0023] The motor drive circuit is used to send a drive voltage control signal;

[0024] The motor is used to be controlled by the motor driving circuit to drive the workbench;

[0025] 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.

[0026] As a further improvement of the implementation mode of the present invention, the low-speed motion control system further includes a detection device for monitoring the motion state information of the motor in real time and sending the motion position and speed of the motor to the motion controller.

[0027] 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 achieve polarization light field splicing or interconnection between different polarization light fields.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 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 patterned liquid crystal light orientation method of pulsed laser illumination to control the phase change of a single exposure area in real time, so as to achieve high-precision and high-resolution exposure;

[0030] 2. The present invention utilizes the characteristics of large pulse laser energy, short pulse width and high repetition frequency to realize single-frame polarization pattern recording based on a single pulse, thus achieving the advantages of large exposure area, high efficiency and good reliability;

[0031] 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 large-format writing;

[0032] 4. The present invention adopts the non-concentrated light energy, and proposes to control the relationship between the size of the single field of view and the single translation distance to eliminate the seams between each light-controlled orientation field of view and improve the resolution;

[0033] 5. The present invention has the advantages of high-precision arbitrary control of single-exposure polarization patterns, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 It is a flow chart of a low-speed motion control method applied to a phase modulation workbench of an LCOS system provided by an embodiment of the present invention;

[0036] Figure 2 It is a schematic structural diagram of a low-speed motion control system applied to a phase modulation workbench of an LCOS system provided by an embodiment of the present invention;

[0037] Figure 3 Schematic diagram of the structure of a high-speed exposure patterned liquid crystal photo-alignment device provided by an embodiment of the present invention;

[0038] Figure 4 It is a schematic diagram of selecting the pulse laser frequency and the refresh frequency of the phase modulation device of the high-speed exposure patterned liquid crystal photo-alignment device in an embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of the peak absorption characteristics of a light polarization sensitive material used in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] On the one hand, the embodiment of the present invention discloses a low-speed motion control method applied to a phase modulation workbench of an LCOS system, such as Figure 1 As shown, the low-speed motion control method includes the following steps:

[0042] S1. Processing the large-format processed graphics to generate corresponding grayscale graphics; the data processing specifically includes pre-correcting the grayscale value of the large-format processed graphics to match the grayscale value of the file with the phase regulation of the LCOS;

[0043] S2, dividing the grayscale graphic into a plurality of grayscale graphic blocks, generating a two-dimensional physical coordinate and a graphic block number corresponding to each grayscale graphic block, and recording the two-dimensional physical coordinate and the graphic block number into a position file, and recording the graphic block number and the file path of the graphic block number into a sequence file; the dividing operation specifically includes dividing the large-format processing graphic into M*N graphic blocks according to a size not greater than the field of view resolution;

[0044] The size of the field of view resolution is LOCS pixel width*pixel height, which can be selected from any one of 1024*768, 1920*1080, and 1920*1152.

[0045] S3, the motion controller reads the two-dimensional physical coordinates in the position file, and controls the workbench to move to a specified position corresponding to the two-dimensional physical coordinates;

[0046] S4, according to the graphic block number corresponding to the two-dimensional physical coordinate, find the file path corresponding to the graphic block number in the sequence file and obtain the grayscale graphic block file;

[0047] S5, uploading the grayscale graphic block file to the LCOS board memory and displaying the grayscale graphic block on the LCOS panel;

[0048] S6, the motion controller controls the pulse light source switch to form one exposure;

[0049] S7, the workbench moves to the designated position corresponding to the next two-dimensional physical coordinate, and the operations of S4-S6 are repeated until the two-dimensional physical coordinate points of the entire large-format processing graphic are completed.

[0050] Specifically, the two-dimensional movement mode of the workbench in S7 moving to the designated position corresponding to the next two-dimensional physical coordinate is consistent with the arrangement order of the two-dimensional physical coordinate points in the position file. When the two-dimensional physical coordinate points in the position file are arranged row by row, the moving workbench moves point by point in row; when the two-dimensional physical coordinate points are arranged column by column, the moving workbench moves point by point in column; when the two-dimensional physical coordinate points are arranged randomly, the moving workbench moves randomly.

[0051] In an embodiment of the present invention, the low-speed motion control method adopts a parallel processing mode of the controller memory and the LCOS board memory; the number of storage points of the controller memory and the LCOS board memory are both N; 2*N two-dimensional physical coordinate data are uploaded to the controller memory; 2*N graphic block number data are uploaded to the LCOS board memory.

[0052] Among them, the specific steps of the parallel processing method of the controller memory and the LCOS board memory in the low-speed motion control method are:

[0053] When working, the data in the first block of memory is executed first. When the data in the first block of memory is executed, the instruction is sent to the controller 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 second block of memory; when the data in the second block of memory is executed, the instruction is sent to the controller to update the data in the second block of memory. At the same time, the workbench does not stop working and continues to execute the data in the first block of memory, and the cycle is repeated.

[0054] On the other hand, the embodiment of the present invention discloses a low-speed motion control system applied to a phase modulation workbench of an LCOS system, such as Figure 2 As shown, the low-speed motion control system includes a workbench, a motion controller, a motor drive circuit and a motor;

[0055] A motion controller, used for receiving the two-dimensional physical coordinate signal of the workbench and sending an exposure switch instruction to the LCOS system phase modulation device;

[0056] A motor drive circuit for sending a drive voltage control signal;

[0057] A motor, used to be controlled by the motor driving circuit to drive the workbench;

[0058] The workbench includes a scanning axis and a position feedback module, and the position feedback module is used for detecting the moving position of the scanning axis in real time.

[0059] Furthermore, the low-speed motion control system also includes a detection device for monitoring the motion state information of the motor in real time and sending the motion position and speed of the motor to the motion controller.

[0060] The workbench carries the light polarization sensitive material and moves in a two-dimensional plane to further realize the splicing of polarized light fields or the interconnection between light fields of different polarizations.

[0061] The low-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 patterned liquid crystal photo-alignment device, such as Figure 3 As shown, it includes an illumination component, a polarization pattern generating component, an imaging detection component, a focus servo system and a motion control component connected in sequence;

[0062] An illumination component, used for providing a light source for continuous stroboscopic exposure and realizing a single polarization collimated uniform surface light spot;

[0063] The polarization pattern generating component includes a quarter wave plate and a phase modulator connected in sequence, and is used to output a pixelated programmable polarization pattern to a workpiece; the phase modulator is connected to the imaging detection component; the phase modulation device is a liquid crystal phase modulation device, and is used to load a different phase to each pixel;

[0064] An imaging detection component is used to detect the generated pattern imaging; the focus servo system includes a normally open light source that is insensitive to light polarization sensitive materials and a vertical direction correction component, which is used to correct the defocus phenomenon caused by movement;

[0065] The motion control component is used to adjust the spatial position of the workbench carrying the light polarization sensitive material to achieve light field stitching.

[0066] In an embodiment of the present invention, the lighting component is a pulse light source, specifically, a pulse laser; in other optional embodiments, the lighting component may also be a continuous light source with a controllable light shielding system; the pulse width of the pulse laser generated by the lighting component is in the range of picoseconds to seconds, and the wavelength of the pulse laser is in the range of 340nm to 600nm; the energy per unit area of ​​the pulse 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.

[0067] In other optional embodiments, the pulse light source may also be generated by a continuous laser plus a mechanical or photoelectric light barrier, or a pulsed LED or a continuous LED plus a controllable light barrier system.

[0068] Preferably, the pulse width of the pulse 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 maintained, at least one pulse laser peak is irradiated onto the phase modulation device.

[0069] In the embodiment of the present invention, the light wavelength emitted by the laser is 442nm, the single pulse energy is 0.2mJ, the pulse width is 10ns, it is pulsed light and S polarization, after being collimated and adjusted by the beam expansion system, and then passing through the polarizer, a spot diameter of 2cm, a divergence angle of less than 10mrad, S polarization, and a light intensity uniformity better than 80% of the collimated uniform spot is formed.

[0070] Specifically, in the embodiment of the present invention, the illumination component includes a collimating assembly and a polarizing plate; the collimating assembly and the polarizing plate constitute a collimating polarizing component.

[0071] The collimating component is used to adjust the line light source or point light source into a parallel surface light source and output it to the polarization image generating component;

[0072] The polarizer is used to produce single polarized light. The polarizer is connected to the collimator assembly to control the initial polarization direction of the light and generate a surface light source with any polarization direction within the range of 0-179 degrees.

[0073] In an embodiment of the present invention, the phase modulation device is a pixel-type phase retarder with adjustable phase difference; and the polarized surface light source is reflected as a light spot containing different polarization information and transmitted to the spectroscopic component; the phase delay amount of the pulse light source modulated by the phase modulation device is greater than 2π; the phase modulation accuracy of a single gray level controlled by a computer program is better than 0.01π, so as to realize arbitrary phase delay modulation within one cycle; the phase delay amount drift of the phase modulation device is less than 0.005π.

[0074] Further, the imaging detection assembly also includes a miniature imaging component;

[0075] A micro-imaging component, used for micro-scaling the polarization pattern output by the polarization pattern generating component and writing it into a light polarization sensitive material;

[0076] The miniature 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 6, and the motor drives the imaging objective lens group to move up and down in the vertical direction to form a focusing surface on the workbench.

[0077] In an embodiment of the present invention, a workbench is disposed 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 at the focal plane of the imaging objective lens group;

[0078] The motion control component is connected to the miniature imaging component and is used for splicing the miniaturized polarization pattern light field.

[0079] The imaging detection component includes a first beam splitter, a tube lens, an imaging objective lens group, a polarizing plate, a first lens, and a first imaging CCD connected in sequence;

[0080] The front focal plane of the imaging objective lens group is located near the back focal plane of the tube lens; the imaging plane of the first imaging CCD is located at the front focal plane of the first lens; and the back focal plane of the first lens is located at the front focal plane of the tube lens.

[0081] As a further improvement of the embodiment of the present invention, the focus 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;

[0082] The detection light source is located at the front focal plane of the second lens; the second beam splitter is located at the back 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;

[0083] The first imaging CCD receives the reflected image projected onto the surface of the light polarization sensitive material, and the first imaging CCD forms a conjugate image with the phase modulator.

[0084] In an embodiment of the present invention, a quarter wave plate is arranged between the phase modulator and the imaging detection component; the phase modulator 22 is a liquid crystal spatial light modulator, which is a pixel-type phase retarder with an adjustable phase difference δ; the polarization rotation direction is one-half δ / 2; the polarization direction of the incident light, the crystal axis direction of the phase modulation device and the crystal axis direction of the quarter wave plate form angles of 0, 45 and 90 degrees.

[0085] In other practicable embodiments, the polarization pattern generating 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.

[0086] 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 angles of 0, 45, and 90 degrees.

[0087] In an embodiment of the present invention, the motion control component further includes a controller, a motor driving device, and a motor detection device, wherein the controller is used to convert the collected optical path data into a control signal and send it to each execution component;

[0088] The controller includes a motion control module, and the motion control module includes a workbench motion control unit;

[0089] 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 movement of the motor in real time and send the movement position and speed of the motor to the motion control module;

[0090] The workbench motion control unit is used to control the movement of light polarization sensitive materials in a two-dimensional plane, so as to realize polarization light field splicing or interconnection between different polarization light fields through pattern splicing components.

[0091] In some embodiments, in order to solve the problem of generating arbitrary polarization orientation, a polarization pattern generating component includes a quarter wave plate and a phase modulator connected in sequence, which is used to generate a pattern of arbitrary polarization distribution; the phase modulator controls the polarization level of each pixel through voltage, and each pixel determines the magnitude of the voltage through different grayscale information, thereby realizing the regulation of polarization information by grayscale images. The grayscale image can be written in real time or preloaded; the phase modulator 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 linear polarized light, thereby realizing pixelated control of the polarization pattern. The resolution of the original polarized light field is determined by the pixel size of the liquid crystal spatial light modulator.

[0092] The specific process of forming the polarization pattern based on the phase modulator is as follows: the fast axis directions of the first quarter wave plate and the second quarter wave plate are orthogonal, and form a 45° angle with the main axis direction of the phase modulator liquid crystal arrangement. After the collimated light spot passes through the first quarter wave plate, it is incident at an angle of 3° with the normal line of the phase modulator to evenly illuminate the phase modulator. The phase modulator used in the embodiment is an LCOS device, with an operating frequency of 50Hz to 400Hz, and a pulse laser damage threshold greater than 300mJ / cm 2 , 10ns, 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 1.54cm*0.86cm, the phase modulation amount for 442nm is greater than 2π, and the phase modulation accuracy is better than 0.03π.

[0093] The light splitting component is connected to the micro-imaging component and the imaging detection component respectively, and is used to filter the light of the specified wavelength band to enter the micro-imaging component and the imaging detection component respectively;

[0094] The motion control component also includes a pattern splicing component, which is used to splice the miniaturized polarized pattern light field.

[0095] The control logic in the embodiment of the present invention is specifically as follows: the control software in the industrial computer 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, and the motor driver controls the motion of the motor according to the received control signal; the detection device is responsible for real-time monitoring of the movement of the motor, and sends the movement 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.

[0096] The phase modulator LCOS in the optical system is connected to the industrial 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 laser light by sending a pulse signal.

[0097] Accordingly, a high-speed exposure patterned liquid crystal photo-alignment method comprises the following steps:

[0098] S1, the line light source or point light source emitted by the light source is adjusted to a collimated polarized plane light source by a polarization collimating device;

[0099] S2, the phase modulation device of the polarization pattern generating component loads the corresponding phase according to the pattern information, reflects the polarized plane light source into a light spot containing different polarization information and transmits it to the light splitting component;

[0100] S3, the light splitting component transmits the light with polarization information to the imaging detection component;

[0101] S4, the servo focusing system adjusts the distance between the imaging objective lens group and the 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;

[0102] S5, recording a single photo-controlled orientation onto a light polarization sensitive material;

[0103] S6. Move the workbench carrying the light polarization sensitive material to the next designated position to record the next pattern light field.

[0104] In an embodiment of the present invention, the following steps are also included after step S3: the miniaturized imaging component forms a fixed miniaturization magnification through the ratio of the focal lengths of the tube lens and the imaging objective lens group, miniaturizes the polarization pattern output by the phase modulation device, and then outputs a polarization pattern light field.

[0105] Furthermore, the high-speed exposure patterned liquid crystal photo-alignment method further comprises, after step S6:

[0106] S7. Splice each alignment unit together to form a light alignment structure with a large-format polarized light pattern on the light polarization sensitive material.

[0107] Wherein, step S2 adjusts the polarization information of each pixel in each sub-image through the grayscale image, specifically including the phase modulation device regulating the polarization level of each pixel through voltage, and each pixel determines the magnitude of the voltage through different grayscale information, thereby realizing the regulation of the grayscale image on the polarization information;

[0108] The grayscale image is written in real time or preloaded;

[0109] The phase modulation device is a high-speed liquid crystal phase modulation device, which acts as a real-time programmable phase plate to perform wavefront correction on linearly polarized light, thereby achieving pixelated control of the polarization pattern.

[0110] Preferably, the wavelength of the light emitted by the detection light source is outside the polarized photosensitivity absorption wavelength region; in step S4, the wavelength of the light emitted by the detection light source is any value between 550nm and 650nm;

[0111] The second lens reflects the light spot projected onto the surface of the polarization-sensitive material to the second imaging CCD. By mapping the Z-axis servo focusing position through the light spot diameter and adjusting the up and down height of the Z-axis lens, the light spot diameter in the second imaging CCD can be kept at R at all times. The size of the light spot projected onto the surface of the polarization-sensitive material can be detected by the second imaging CCD to determine whether the surface of the polarization-sensitive material is on the focusing plane of the objective lens.

[0112] In the embodiment of the present invention, after the single polarization pattern is recorded on the light polarization sensitive material, step S6 moves the workbench carrying the light polarization sensitive material to the next designated position for the next orientation, which is specifically implemented by the following steps:

[0113] The controller 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 controls the motion of the motor according to the received control signal. The detection device is responsible for monitoring the movement of the motor in real time and sending the movement 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.

[0114] After a single photo-controlled orientation is recorded on the light polarization-sensitive material, the motion control module moves the workbench carrying the light polarization-sensitive material to the next specified position. The moving distance is the size of the single orientation unit, and the moving method is to move and scan row by row. 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 with multiple laser pulses.

[0115] Among them, the relationship between the pulse laser frequency and the phase modulation device refresh frequency is as follows: Figure 4 As shown, the pulse laser frequency of the pulse laser corresponds to the frequency of the phase modulation device, and the pulse width is less than or equal to the image maintenance time of the phase modulation device, that is, when an image of the phase modulation device is maintained, a pulse laser 11 peak is irradiated onto the phase modulation device.

[0116] During the image holding time of the phase modulation device, multiple pulse laser peaks may be irradiated onto the receiving window of the phase modulation device, thereby enhancing the single exposure energy.

[0117] The wavelength absorption characteristics of the photo-controlled alignment material used in this embodiment are as follows: Figure 5 As shown; the material used is azo photo-alignment material, corresponding to Figure 5For material 3, a better light-controlled orientation effect can be obtained when using laser illumination with a wavelength of 442nm. Pulse laser light sources with different wavelengths can also be selected according to the light-oriented material, or the corresponding light-oriented material can be selected according to the pulse laser light sources with different wavelengths. The miniaturized component uses a 20x miniaturized objective lens, that is, the spot area is reduced by 400 times, and the energy density is increased by 400 times. After miniaturization, the size of a single pixel is only 0.4 microns, which can achieve high-precision pattern information exposure direct writing. At this time, the photosensitivity of the light-oriented material is 50mJ / cm 2 , higher than the photo-controlled orientation energy threshold and lower than its damage threshold.

[0118] It should be noted that the "stroboscopic" defined in the present invention is the emission and / or quenching at a certain preset frequency.

[0119] Compared with the prior art, the present invention has the following beneficial effects:

[0120] 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 patterned liquid crystal light orientation method of pulsed laser illumination to control the phase change of a single exposure area in real time, so as to achieve high-precision and high-resolution exposure;

[0121] 2. The present invention utilizes the characteristics of large pulse laser energy, short pulse width and high repetition frequency to realize single-frame polarization pattern recording based on a single pulse, thus achieving the advantages of large exposure area, high efficiency and good reliability;

[0122] 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 large-format writing;

[0123] 4. The present invention adopts the non-concentrated light energy, and proposes to control the relationship between the size of the single field of view and the single translation distance to eliminate the seams between each light-controlled orientation field of view and improve the resolution;

[0124] 5. The present invention has the advantages of high-precision arbitrary control of single-exposure polarization patterns, 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.

[0125] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present invention, which will not be described in detail here.

[0126] It should be noted that: when a motion control system provided in the above embodiment executes a motion control method, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the system can be divided into different functional modules to complete all or part of the functions described above. In addition, the motion control system and the motion control method embodiment provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0127] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0128] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-speed motion control method applied to a phase modulation workbench of an LCOS system, characterized in that: The low-speed motion control method comprises the following steps: S1, processing the large-format processed graphics to generate corresponding grayscale graphics; S2, dividing the grayscale graphic into a plurality of grayscale graphic blocks, generating a two-dimensional physical coordinate and a graphic block number corresponding to each grayscale graphic block, and recording the two-dimensional physical coordinate and the graphic block number into a position file, and recording the graphic block number and the file path of the graphic block number into a sequence file; S3, the motion controller reads the two-dimensional physical coordinates in the position file, and controls the workbench to move to a specified position corresponding to the two-dimensional physical coordinates; S4, according to the graphic block number corresponding to the two-dimensional physical coordinate, find the file path corresponding to the graphic block number in the sequence file and obtain the grayscale graphic block file; S5, uploading the grayscale graphic block file to the LCOS board memory and displaying the grayscale graphic block on the LCOS panel; S6, the motion controller controls the pulse light source switch to form one exposure; S7, the workbench moves to the designated position corresponding to the next two-dimensional physical coordinate, and the operations of S4-S6 are repeated until the two-dimensional physical coordinate points of the entire large-format processing graphic are completed.

2. The low-speed motion control method applied to the LCOS system phase modulation workbench according to claim 1 is characterized in that: The data processing in S1 specifically includes pre-correcting the grayscale value of the large-format processed graphics so that the grayscale value of the file matches the phase regulation of the LCOS.

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

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

5. The low-speed motion control method applied to the LCOS system phase modulation workbench according to claim 1, characterized in that: The two-dimensional movement mode of the workbench in S7 moving to the specified position corresponding to the next two-dimensional physical coordinate is consistent with the arrangement order of the two-dimensional physical coordinate points in the position file: when the two-dimensional physical coordinate points in the position file are arranged one by one in rows, the motion workbench moves point by point in rows; when the two-dimensional physical coordinate points are arranged one by one in columns, the motion workbench moves point by point in columns; when the two-dimensional physical coordinate points are arranged randomly, the motion workbench moves randomly.

6. The low-speed motion control method applied to the LCOS system phase modulation workbench according to claim 1, characterized in that: The low-speed motion control method adopts a parallel processing mode of the controller memory and the LCOS board memory; the number of storage points of the controller memory and the LCOS board memory are both N; 2*N two-dimensional physical coordinate data are uploaded to the controller memory; Upload 2*N graphic block number data in the LCOS board memory.

7. The low-speed motion control method applied to the LCOS system phase modulation workbench according to claim 6, characterized in that: The specific steps of the parallel processing of the controller memory and the LCOS board memory in the low-speed motion control method are as follows: When working, the data in the first block of memory is executed first. When the data in the first block of memory is executed, the instruction is sent to the controller 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 second block of memory; when the data in the second block of memory is executed, the instruction is sent to the controller to update the data in the second block of memory. At the same time, the workbench does not stop working and continues to execute the data in the first block of memory, and the cycle is repeated.

8. A low-speed motion control system applied to a phase modulation workbench of an LCOS system, characterized in that: Used to execute the low-speed motion control method applied to the phase modulation workbench of the LCOS system according to any one of claims 1 to 7, wherein the low-speed motion control system comprises 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 instruction to the LCOS system phase modulation device; The motor drive circuit is used to send a drive voltage control signal; The motor is used to be controlled by the motor driving 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.

9. The low-speed motion control system applied to the LCOS system phase modulation workbench according to claim 8, characterized in that: The low-speed motion control system further comprises a detection device for monitoring the motion state information of the motor in real time and sending the motion position and speed of the motor to a motion controller.

10. The low-speed motion control system applied to the LCOS system phase modulation workbench according to claim 8, characterized in that: The workbench carries the light polarization sensitive material and moves in a two-dimensional plane to further realize polarization light field splicing or interconnection between different polarization light fields.

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