Array light beam generation device based on acousto-optic deflector and parallel scanning method

Abstract

The invention discloses an array light beam generation device based on an acousto-optic deflector and a parallel scanning method, and belongs to the technical field of laser. According to the array light beam generation device of the acousto-optic deflector and the parallel scanning method, the two acousto-optic beam splitting units are used for splitting laser beams in two different directions to form a laser beam array, the number of points obtained through single scanning is large, and the energy utilization rate is high; the to-be-scanned pattern is decomposed into a plurality of matrixes which can be scanned once, so that the scanning times are reduced, the scanning time is shortened, and the efficiency is relatively high.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and more specifically, relates to an array light beam generating device based on an acousto-optic deflector and a parallel scanning method. Background Art

[0002] With the development of laser technology, laser scanning has been widely used and developed in the fields of precision machining, projection display, industrial measurement, laser radar, etc.

[0003] There are many ways to scan complex patterns with lasers, such as vector scanning, spiral scanning, random scanning, line scanning, etc. However, single-point scanning is slow, the time is limited by the movement speed of the machine, the efficiency is relatively low, and the required energy is lower than the laser output power, wasting most of the energy.

[0004] In order to improve energy utilization and processing efficiency, microlens arrays, diffractive optical elements (DOEs), spatial light modulators (SLMs), acousto-optic modulators (AOMs) and other components are used to divide the laser beam into multiple beams more evenly to achieve laser parallel scanning.

[0005] The microlens array consists of multiple micron-sized microlenses arranged in a certain pattern, which can split the incident single laser beam into multiple sub-beams, each sub-beam corresponds to a microlens, thereby achieving parallel scanning. However, it is sensitive to the angle and wavelength of the incident light, and requires high manufacturing precision. After the production is completed, the beam splitting mode and parameters are basically fixed, and the application scenarios are limited.

[0006] The diffractive optical element beam splitting method diffracts the incident light by making a microstructure on the surface of the element, thereby changing the propagation direction and intensity distribution of the light and splitting the light beam. However, it is impossible to actively control the sub-beams, and the system parameters are mutually restricted, which is costly and inflexible. In addition, there are certain energy losses and zero-order interference problems, which affect the uniformity of light intensity.

[0007] The spatial light modulator changes the control voltage at both ends of the liquid crystal by inputting different grayscale information, deflecting the liquid crystal molecules, thereby changing the optical path difference of the incident light, modulating the amplitude, phase, polarization state and other information of the laser, and achieving the purpose of flexible beam splitting. However, its damage threshold is low, the modulation speed is slow, and it will produce coherent artifacts that affect the scanning accuracy.

[0008] The acousto-optic modulator uses the acousto-optic effect. When the laser passes through the acousto-optic medium, diffraction occurs, thereby dividing a single laser beam into multiple beams. By controlling the driving signal of the acousto-optic modulator, the energy, spacing, direction and other parameters of each sub-beam can be flexibly adjusted to achieve precise control of the beam, providing technical support for high-speed parallel processing.

[0009] Commonly used laser beam splitting devices have problems such as poor flexibility, low damage threshold, poor scanning accuracy, and low energy utilization. After beam splitting, other scanning devices are usually combined to control the scanning path of each sub-beam, which has a complex structure and high cost. In addition, traditional parallel scanning mostly uses row-by-row or column-by-column scanning methods. For more complex patterns, the scanning times are too many, the time is long, and the efficiency is low. Summary of the invention

[0010] In view of the above defects or improvement needs of the prior art, the present invention provides an array beam generating device and a parallel scanning method based on an acousto-optic deflector, which aims to solve the problems of poor flexibility, poor scanning accuracy, low processing efficiency, and complex structure in laser scanning.

[0011] To achieve the above-mentioned object, according to one aspect of the present invention, the present invention provides an array beam generating device method based on an acousto-optic deflector, comprising: a laser, a collimator, an acousto-optic beam splitting module, a lens group and a focusing lens arranged in sequence along an optical path; the acousto-optic beam splitting module comprises a first acousto-optic beam splitting unit and a second acousto-optic beam splitting unit connected in sequence; the first acousto-optic beam splitting unit comprises a first signal generator, a first radio frequency amplifier and a first acousto-optic deflector, the first acousto-optic deflector comprises a first ultrasonic transducer and a first acousto-optic medium, the second acousto-optic beam splitting unit comprises a second signal generator a first or second signal generator for generating a driving signal for driving the corresponding first or second acousto-optic deflector, the driving signal is amplified by the corresponding first or second radio frequency amplifier, converted into an ultrasonic signal by the first or second ultrasonic transducer, and injected into the corresponding first or second acousto-optic medium to form a grating, and the parameters such as the spacing and position of the grating are controlled by changing the driving signal to realize dynamic editing of the grating, thereby realizing diffraction deflection of the incident light in multiple directions;

[0012] The laser is used to output linearly polarized light, which is collimated by a collimator and incident on a first acousto-optic deflector along a main optical path, and is divided into one-dimensional multi-path output light beams in the beam splitting direction thereof. The multi-path output light beams are incident on a second acousto-optic deflector, and are diffracted and deflected in multiple directions. Each output light beam is split in the beam splitting direction of a second acousto-optic beam splitting unit to generate a two-dimensional multi-path output light beam. The two-dimensional multi-path output light beams are collimated by a lens group and incident on a focusing lens, forming an array light beam at the focal plane of the focusing lens.

[0013] Furthermore, the lens group includes a first lens and a second lens which are sequentially arranged along the optical path, and the acousto-optical beam splitting module is located at the front focus of the first lens.

[0014] Furthermore, the beam splitting directions of the first acousto-optic deflector and the second acousto-optic deflector are perpendicular.

[0015] Preferably, the first acousto-optic medium and the second acousto-optic medium are AOD crystals.

[0016] Furthermore, the driving signal is converted into N single-frequency ultrasonic signals s by the ultrasonic transducer. i Linear superposition of (t):

[0017]

[0018] Among them A i , f i , Represent the amplitude, frequency and phase of a single frequency signal respectively.

[0019] The collimated light beam with a frequency of v0 is incident on the first acousto-optic deflector, which will cause Bragg diffraction and produce a certain frequency shift:

[0020] v i d =v0±f 1i

[0021] Among them, v i d is the frequency of the i-th diffracted sub-beam, f 1i is the frequency of a single-frequency signal in the input signal of the first acousto-optic deflector, where + represents +1-order diffraction and - represents -1-order diffraction;

[0022] The i-th diffracted sub-beam of the first AOD is incident on the second AOD, resulting in frequency shift:

[0023]

[0024] Among them, v ij d is the jth diffracted output beam corresponding to the i-th beam incident on the second acousto-optic deflector, f 2j is the frequency of a single frequency signal in the input signal of the second acousto-optic deflector.

[0025] The output beam deflection angle Δθ in each beam splitting direction t It can be expressed as:

[0026]

[0027] Where λ0 is the wavelength of the incident laser beam, V is the speed of sound in the acousto-optic medium, and Δf t is the frequency difference between the outgoing light beam and the incident light beam in the splitting direction of the tth acousto-optic deflector.

[0028] After the sub-beam deflected by the second acousto-optic deflector is focused by a focusing mirror with a focal length of F, an array of light spots is formed on the focal plane. The distance Δl between the light spot and the center point can be expressed as:

[0029]

[0030] Wherein, F is the focal length of the focusing lens, and Δθ is the deflection angle of the outgoing light.

[0031] Therefore, the position of the outgoing light beam after focusing is determined by the frequency of the input signal.

[0032] The ultrasonic cross-sectional area in the acousto-optic deflector is the area of ​​the ultrasonic transducer that excites it, which is equal to the product of its length L and width H. According to the formula of Bragg diffraction efficiency:

[0033]

[0034] Among them, M2 is the acoustic-optical figure of merit, P a is the acoustic power. The larger the input signal amplitude, the stronger the acoustic field excited by the ultrasonic transducer. The larger the acoustic power, the greater the diffraction efficiency and the stronger the output beam.

[0035] When the input signal enters the RF amplifier, nonlinear amplification will occur when the power is high, resulting in a certain degree of distortion of the output signal, nonlinear intermodulation, poor uniformity of the split beam spot, and the appearance of additional diffraction beams, which greatly reduces the diffraction efficiency. Phase modulation of the input signal can improve the diffraction efficiency and increase the intensity of the output beam.

[0036] Therefore, the spot intensity of the outgoing light beam is determined by the amplitude and phase of the input signal. Dynamic editing of the spot intensity can be achieved by changing the amplitude and phase of the input signal.

[0037] The lens group forms a 4F system, the acousto-optical beam splitting module is located at the front focus of the first lens, and the focal lengths of the two lenses are f1 and f2 respectively, which can increase the spacing between the laser beams in the laser beam array and the spot area of ​​each laser beam, and generate multiple collimated and non-overlapping laser beams.

[0038] The focusing lens is used to focus the collimated multiple laser beams and scan the array on the focal plane.

[0039] The present invention also provides a parallel scanning method based on the above array beam generating device based on the acousto-optic deflector, comprising the following steps:

[0040] S1: converting the pattern to be processed into a matrix form;

[0041] S2: Find the rank of the matrix. If the matrix is ​​full rank, scan it row by row or column by column. If the rank is less than the number of rows or columns, execute step S3.

[0042] S3: Decompose the matrix into multiple sub-matrices and add them together, set the parameters of the corresponding driving signal for this scan according to each sub-matrix, and perform a single scan on each matrix in turn to obtain the pattern to be processed.

[0043] Optionally, the two acousto-optic deflectors have perpendicular beam splitting directions, respectively along the X and Y directions; when the X-direction driving signal contains a frequency of f xi The Y-direction driving signal contains a single-frequency signal with a frequency of f yj When a single frequency signal is generated, a deflection angle of Δθ will be generated. ij The projection angles of the outgoing beam in the X and Y directions satisfy:

[0044]

[0045] The laser beam splitting in the X and Y directions can be represented by a column vector u and a row vector ν:

[0046]

[0047] The elements in the column vector u correspond to different input frequencies in the X direction, and the elements in the row vector ν correspond to different input frequencies in the Y direction. The range and interval of the incident frequencies are determined by the size of the image to be scanned and the number of points to be scanned.

[0048] For a single scan:

[0049] If the X-direction driving frequency during this scan includes f xi , then the corresponding element u i Non-zero if the Y-direction drive frequency contains f yj , then the corresponding element v j Non-zero, the elements corresponding to the frequencies not included in the driving signal are set to zero;

[0050] The image obtained after scanning can be represented by matrix A:

[0051]

[0052] The element corresponding to the position scanned by the laser beam is non-zero, and the element corresponding to the position without the laser beam is zero if and only if u i and v j When non-zero, the element u in A i v j Non-zero, that is, if and only if the driving signal contains a frequency of f xi and frequency f yj When a single frequency signal is generated, a deflection angle of Δθ will be generated. ij The outgoing light beam can irradiate the corresponding position Δl ij superior;

[0053] According to the properties of matrix rank:

[0054] r(AB)≤min{r(A),r(B)}

[0055] u and ν are non-zero vectors with a rank of 1, so the rank of the matrix A is 1, and the rank of the matrix obtained by a single scan is 1;

[0056] For any matrix of rank 1, any row can be linearly represented by a specified row, and the matrix of rank 1 can be decomposed into the product of a column vector and a row vector.

[0057] Therefore, the matrix corresponding to the image obtained by a single scan corresponds one-to-one to the matrix of rank 1, and the number of scans is the number of matrices of rank 1 that the matrix can be decomposed into;

[0058] For a matrix of rank r, the minimum number of rank-1 matrices that can be decomposed is the rank of the matrix.

[0059] In some embodiments, the laser beam intensity is uniform, and in step S1, the part with laser scanning is set to 1, and the part without laser scanning is set to 0. The converted matrix elements are only 0 or 1, that is, a Boolean matrix; the corresponding step S3 is Boolean matrix decomposition:

[0060] A m×n =B m×k ×C k×n

[0061] Where A m×n , B m×k and C k×n All are Boolean matrices;

[0062] Preferably, step S3 may be performed using the MEBF method, and the specific steps are as follows:

[0063] S31: Rearrange the rows and columns of the matrix to obtain an approximate UTL matrix with the closest direct SC1P, so that the 1s in the matrix are concentrated in the upper left corner;

[0064] S32: Find the row or column with a medium number of 1s as the basis;

[0065] S33: Extend the middle row or column to other columns or rows through bidirectional growth to cover as large a range as possible without causing errors;

[0066] S34: Find out the number of rows of the covered part when the matrix is ​​not rearranged, set the row corresponding to the first column of matrix B to 1, and the remaining rows to 0. Similarly, find out the number of columns of the covered part in the original matrix, set the column corresponding to the first row of matrix C to 1, and the remaining columns to 0.

[0067] S35: subtract the covered part from the original matrix to obtain a new matrix;

[0068] S36: Repeat steps S31 to S35 to obtain the 2nd to kth columns of matrix B and the 2nd to kth rows of matrix C in sequence until the matrix decomposition is complete. If there are a few points left that are not covered, a point-by-point scan can be performed at the end.

[0069] Preferably, step S4 specifically includes:

[0070] S41: Matrix A m×n Decompose into B m×k and C k×n , matrix B m×k The i-th column of the matrix C k×n The matrix obtained by scanning the i-th time is multiplied by the i-th row of , where i = 1, 2, ..., k;

[0071] S42: Calculate the maximum required deflection angle according to the size of the pattern to be scanned, thereby calculating the variation range of the input frequency, and determine the frequency interval of the input frequency according to the intervals of the sub-matrices in the X and Y directions obtained by each scan;

[0072] S43: Determine the center frequency and find the frequency of each single frequency signal of the driving signal;

[0073] S44: Calculate the amplitude and phase corresponding to each frequency;

[0074] S45: linearly superimposing the single-frequency signals to obtain a driving signal, wherein the driving signal varies with the number of scans;

[0075] Optionally, step S44 may adopt a random search method, taking the average-to-peak ratio as a constraint condition, performing multiple calculations, taking the one with the smallest average-to-peak ratio as the optimized phase, and then optimizing the amplitude according to the collected light spot. After multiple iterations, the relationship between the output power of each frequency point of the two-dimensional AOD and the amplitude and phase of the input signal is obtained, and a data table is prepared. According to the required light spot intensity, the amplitude and phase corresponding to different frequencies are searched to obtain the input signal;

[0076] Compared with the prior art, the above technical solutions conceived by the present invention can achieve the following

[0077] Beneficial effects:

[0078] 1. The array beam generating device and parallel scanning method of the acousto-optic deflector proposed in the present invention utilize two acousto-optic beam splitting units to split the laser beam in two different directions to form a laser beam array, with a large number of points scanned in a single scan and high energy utilization rate; by decomposing the pattern to be scanned into multiple matrices that can be completed in a single scan, the number of scans is reduced, the scanning time is shortened, and the efficiency is high;

[0079] 2. The laser parallel scanning method proposed in the present invention utilizes acousto-optic medium beam splitting. The angle and intensity of the sub-beam are modulated in real time by the driving signal of the acousto-optic beam splitting module. The amplitude, frequency and phase of the driving signal are set according to the matrix parameters obtained by decomposition. By adjusting the input waveform, the laser beam array can be dynamically controlled, which has high flexibility.

[0080] 3. The present invention mainly uses acousto-optic devices and lenses for regulation, without the need for liquid crystal regulation, and has an extremely high damage threshold;

[0081] 4. The laser parallel scanning method proposed in the present invention does not need to be combined with other complex scanning devices and has a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 It is a structural schematic diagram of a laser parallel scanning device based on acousto-optical beam splitting used in the present invention;

[0083] Figure 2 is a schematic diagram of a single acousto-optic beam splitting module used in the present invention;

[0084] Figure 3 It is a schematic diagram of a beam array formed by two acousto-optic beam splitting modules in the present invention;

[0085] Figure 4 is a schematic diagram of a process of laser parallel scanning of patterns in an embodiment of the present invention;

[0086] Figure 5 is a schematic diagram of decomposing a pattern into multiple single-scan patterns in an embodiment of the present invention;

[0087] Figure 6 is a schematic diagram of parallel scanning based on beam array and matrix decomposition in Embodiment 1 of the present invention;

[0088] Figure 7 Schematic diagram of a laser parallel scanning grayscale pattern in an embodiment of the present invention;

[0089] Figure numerals: 1. laser, 2. collimator, 3. acousto-optic beam splitting module, 4. lens group, 5. focusing lens, 6. scanning plane, 31. first acousto-optic deflector, 32. second acousto-optic deflector, 33. first radio frequency amplifier, 34. second radio frequency amplifier, 35. first signal generator, 36. second signal generator, 41. first lens, 42. second lens, 61. focal plane of focusing lens. DETAILED DESCRIPTION

[0090] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0091] The present invention provides an array beam generating device method based on an acousto-optic deflector, comprising: a laser, a collimator, an acousto-optic beam splitting module, a lens group and a focusing lens arranged in sequence along an optical path; the acousto-optic beam splitting module comprises a first acousto-optic beam splitting unit and a second acousto-optic beam splitting unit connected in sequence; the first acousto-optic beam splitting unit comprises a first signal generator, a first radio frequency amplifier and a first acousto-optic deflector, the first acousto-optic deflector comprises a first ultrasonic transducer and a first acousto-optic medium, the second acousto-optic beam splitting unit comprises a second signal generator, a second radio frequency amplifier and a second acousto-optic deflector, the second acousto-optic deflector comprises a second ultrasonic transducer and a second acousto-optic medium; the first or second signal generator is used to generate a driving signal for driving the corresponding first or second acousto-optic deflector, the driving signal is converted into an ultrasonic signal by the first or second ultrasonic transducer after being power amplified by the corresponding first or second radio frequency amplifier, and injected into the corresponding first or second acousto-optic medium to form an editable dynamic grating, so as to realize diffraction deflection of incident light in multiple directions;

[0092] The laser is used to output linearly polarized light, which is collimated by a collimator and incident on a first acousto-optic deflector along a main optical path, and is divided into one-dimensional multi-path output light beams in the beam splitting direction thereof. The multi-path output light beams are incident on a second acousto-optic deflector, and are diffracted and deflected in multiple directions. Each output light beam is split in the beam splitting direction of a second acousto-optic beam splitting unit to generate a two-dimensional multi-path output light beam. The two-dimensional multi-path output light beams are collimated by a lens group and incident on a focusing lens, forming an array light beam at the focal plane of the focusing lens.

[0093] The present invention also provides a parallel scanning method based on the above array beam generating device based on the acousto-optic deflector, comprising the following steps:

[0094] S1: converting the pattern to be processed into a matrix form;

[0095] S2: Find the rank of the matrix. If the matrix is ​​full rank, scan it row by row or column by column. If the rank is less than the number of rows or columns, execute step S3.

[0096] S3: Decompose the matrix into multiple sub-matrices and add them together, set the parameters of the corresponding driving signal for this scan according to each sub-matrix, and perform a single scan on each matrix in turn to obtain the pattern to be processed.

[0097] The contents involved in the above embodiments are described below in conjunction with preferred embodiments.

[0098] Embodiment 1

[0099] like Figure 1 The figure shows a schematic diagram of the structure of a laser parallel scanning device based on acousto-optical beam splitting used in an example of the present invention, comprising a laser 1, a collimator 2, two acousto-optical beam splitting modules 3, a lens group 4, a focusing lens 5 and a scanning plane 6 arranged in sequence along the optical path;

[0100] The laser 1 outputs linearly polarized light, which is collimated by the collimator 2 and then incident on the acousto-optical beam splitting module 3 along the main optical path;

[0101] The two acousto-optical beam splitting modules 3 include two groups of arbitrary signal generators, namely a first signal generator 35 and a second signal generator 36, a first radio frequency amplifier 33 and a second radio frequency amplifier 34, a first acousto-optical deflector 31 and a second acousto-optical deflector 32;

[0102] The module 4 includes two focusing lenses, namely a first lens 41 and a second lens 42, which form a 4F system;

[0103] The sub-beam array formed by the acousto-optical beam splitting module 3 is amplified by the 4F system composed of two lenses of the module 4;

[0104] The focusing lens 5 is used to focus the multiple laser beam arrays and scan a light spot array on the scanning plane 6 .

[0105] like Figure 2 FIG. 1 is a schematic diagram of a first acousto-optical beam splitting unit in an embodiment of the present invention. The first signal generator 35 is used to generate a driving signal. The driving signal is linearly superimposed by multiple single-frequency signals. After the signal is amplified by the first radio frequency amplifier 33, it is injected into the first acousto-optic medium to form a grating to achieve beam splitting of the incident laser.

[0106] like Figure 3 The figure shows a schematic diagram of a beam array formed by two acousto-optical beam splitting modules in the present invention. The first signal generator 35 is used to generate a driving signal in the Y direction, which is amplified by the first radio frequency amplifier 33 and then injected into the first acousto-optical deflector 31, so that the laser is split in the Y direction. The second signal generator 36 is used to generate a driving signal in the X direction, which is amplified by the second radio frequency amplifier 34 and then injected into the second acousto-optical deflector 32, so that the laser is split in the X direction. When the driving signal in the X direction contains a frequency of f xi The Y-direction driving signal contains a single-frequency signal with a frequency of f yj When a single frequency signal is generated, a deflection angle of Δθ will be generated. ij The outgoing light beam.

[0107] Figure 4 A is the pattern to be scanned in this embodiment. The specific steps of generating a beam array based on an acousto-optic deflector and performing laser parallel scanning by using matrix decomposition include:

[0108] S1: convert the pattern to be processed into a matrix form;

[0109] In this embodiment, the intensity of the laser beam splitting is uniform, the parts with laser processing are set to 1, and the parts without laser processing are set to 0. The converted matrix elements are only 0 or 1, that is, the pattern can be converted into a Boolean matrix:

[0110]

[0111] S2: Find the rank of the matrix and determine the minimum number of decomposition scans. If the matrix is ​​almost full rank, use row-by-row or column-by-column scanning. If its rank is significantly smaller than the number of rows and columns, execute step S3.

[0112] In this embodiment, the number of rows and columns of the matrix is ​​11, and the rank of the matrix is ​​5, which is significantly smaller than the number of rows and columns. A matrix decomposition method is used to reduce the number of scans.

[0113] S3: Decompose the matrix into multiple matrices and add them together. Each matrix can be obtained by a single scan. Perform Boolean matrix decomposition on the original matrix:

[0114] A m×n =B m×k ×C k×n

[0115] Preferably, the MEBF method is adopted, and the specific steps are:

[0116] S31: Rearrange the rows and columns of the matrix to obtain an approximate UTL matrix with the closest direct SC1P, so that the 1s in the matrix are concentrated in the upper left corner;

[0117] S32: Find the row or column with a medium number of 1s as the basis;

[0118] S33: Extend the middle row or column to other columns or rows through bidirectional growth to cover as large a range as possible without causing errors;

[0119] S34: Find out the number of rows of the covered part when the matrix is ​​not rearranged, set the row corresponding to the first column of matrix B to 1, and the remaining rows to 0. Similarly, find out the number of columns of the covered part in the original matrix, set the column corresponding to the first row of matrix C to 1, and the remaining columns to 0.

[0120] S35: subtract the covered part from the original matrix to obtain a new matrix;

[0121] S36: Repeat steps S31 to S35 to obtain the 2nd to kth columns of matrix B and the 2nd to kth rows of matrix C in sequence until the matrix decomposition is complete. If there are a few points left that are not covered, a point-by-point scan can be performed at the end.

[0122] In this embodiment, the Boolean matrix decomposition result is:

[0123] A 11×11 =B 11×5 ×C 5×11

[0124] Among them, B 11×5 and C 5×11 Specifically:

[0125]

[0126] S4: Setting parameters according to each sub-matrix, including:

[0127] S41: Matrix A m×n Decompose into B m×k and C k×n , matrix B m×k The i-th column of the matrix C k×n The matrix obtained by scanning the i-th time is multiplied by the i-th row of , where i = 1, 2, ..., k;

[0128] For example, the matrix scanned for the first time is B 11×5 The first column and C 5×11 Multiply the first row of :

[0129]

[0130] From the matrix decomposition results, we can see that A 11×11 Decompose into B 11×5 and C 5×11 , can be divided into 5 scans.

[0131] like Figure 5 The figure is a schematic diagram of decomposing a pattern into multiple single-scan graphics in an embodiment of the present invention. The matrix into which the pattern to be scanned is converted can be decomposed into five sub-matrices added together, wherein the pattern corresponding to each matrix can be obtained by a single scan.

[0132] S42: Calculate the maximum required deflection angle according to the size of the pattern to be scanned, thereby calculating the variation range of the input frequency, and determine the frequency interval of the input frequency according to the intervals of the sub-matrices in the X and Y directions obtained in each scan.

[0133] S43: Determine the center frequency f0, obtain the range of the input frequency, and then obtain the output frequency of each single frequency signal.

[0134] S44: Find the optimal amplitude and phase corresponding to each frequency.

[0135] Step S44 can adopt a random search method, taking the average-to-peak ratio as a constraint condition, calculating multiple times, taking the one with the smallest average-to-peak ratio as the optimized phase, and then optimizing the amplitude according to the collected light spot. After multiple iterations, the relationship between the output power of each frequency point of the two-dimensional AOD and the amplitude and phase of the input signal is obtained, and a data table is made. According to the required light spot intensity, the amplitude and phase corresponding to different frequencies are searched to obtain the input signal.

[0136] In this embodiment, the intensity of the light spot is consistent and uniform, and a suitable output power is selected to find the amplitude and phase corresponding to different frequencies in the data table.

[0137] S45: linearly superimposing the single-frequency signals to obtain a driving signal, wherein the driving signal varies with the number of scans.

[0138] like Figure 6 That is, it is a schematic diagram of the process of using matrix decomposition to find the input frequency corresponding to each beam array and perform parallel scanning.

[0139] like Figure 4 B to F in the figure are schematic diagrams of the five scanning processes in this embodiment, and the black solid dots are the laser beam arrays scanned during this scanning.

[0140] Embodiment 2

[0141] like Figure 7 A in the figure is the pattern to be scanned in this embodiment. In this embodiment, the pattern has grayscale changes, and the intensity of the required laser beam array is uneven. The intensity can be dynamically adjusted by controlling the amplitude and phase of the input signal to achieve grayscale editable scanning.

[0142] The specific steps of generating a beam array based on an acousto-optic deflector and performing parallel scanning using matrix decomposition include:

[0143] S1: convert the pattern to be processed into a matrix form;

[0144] According to the grayscale of the pattern, the matrix elements corresponding to different positions take different values, and the value is proportional to the required laser spot intensity:

[0145]

[0146] S2: Find the rank of the matrix and determine the minimum number of decomposition scans. If the matrix is ​​almost full rank, use row-by-row or column-by-column scanning. If its rank is significantly smaller than the number of rows and columns, execute step S3.

[0147] In this embodiment, the number of rows and columns of the matrix is ​​9, and the rank of the matrix is ​​3, which is significantly smaller than the number of rows and columns. The matrix decomposition method is used to reduce the number of scans;

[0148] S3: Decompose the matrix into multiple matrices and add them together. Each matrix can be obtained by a single scan. Perform Boolean matrix decomposition on the original matrix:

[0149] A m×n =B m×k ×C k×n

[0150] In this embodiment, the Boolean matrix decomposition result is:

[0151] A 9×9 =B 9×3 ×C 3×9

[0152] Among them, B 9×3 and C 3×9 Specifically:

[0153]

[0154] S4: Setting parameters according to each sub-matrix, including:

[0155] S41: Matrix A m×n Decompose into B m×k and C k×n , matrix B m×k The i-th column of the matrix C k×n The matrix obtained by the i-th scan is multiplied by the i-th row of , where i = 1, 2, …, k.

[0156] From the matrix decomposition results, we can see that it can be divided into three scans.

[0157] like Figure 7 B to D in the figure are schematic diagrams showing decomposing a pattern into multiple single-scan graphics in an embodiment of the present invention. The matrix into which the pattern to be scanned is converted can be decomposed into the addition of three sub-matrices, wherein the pattern corresponding to each matrix can be obtained by a single scan.

[0158] S42: Calculate the maximum required deflection angle according to the size of the pattern to be scanned, thereby calculating the variation range of the input frequency, and determine the frequency interval of the input frequency according to the intervals of the sub-matrices in the X and Y directions obtained in each scan.

[0159] S43: Determine the center frequency f0, obtain the range of the input frequency, and then obtain the output frequency of each single frequency signal.

[0160] S44: Calculate the optimal amplitude and phase corresponding to each frequency so that the intensity of the outgoing light beam spot is proportional to the matrix element value.

[0161] According to the required spot intensity at different frequency points, calculate the output power of the light beams at different frequencies after the acousto-optic medium splits them, find the amplitude and phase corresponding to the required output power at this frequency in the table, and get the parameters of the input signal.

[0162] S45: linearly superimposing the single-frequency signals to obtain a driving signal, wherein the driving signal varies with the number of scans.

[0163] In some embodiments, the acousto-optical beam splitting module may also be equipped with a lens so that the beam splitting direction is not vertical.

[0164] In some embodiments, the intensity of the laser beam splitting is uneven and a grayscale pattern is scanned, that is, in step S44, different output light spots have different intensities, and the corresponding amplitude and phase are searched in the table according to the output light spot intensity.

[0165] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0166] The present invention is described in detail above in conjunction with the embodiments, but it should not be understood as limiting the scope of the patent application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An array beam generating device based on an acousto-optic deflector, characterized in that: It comprises a laser, a collimator, an acousto-optical beam splitting module, a lens group and a focusing lens arranged in sequence along an optical path; the acousto-optical beam splitting module comprises a first acousto-optical beam splitting unit and a second acousto-optical beam splitting unit connected in sequence; the first acousto-optical beam splitting unit comprises a first signal generator, a first radio frequency amplifier and a first acousto-optical deflector, the first acousto-optical deflector comprises a first ultrasonic transducer and a first acousto-optical medium, the second acousto-optical beam splitting unit comprises a second signal generator, a second radio frequency amplifier and a second acousto-optical deflector, the second acousto-optical deflector comprises a second ultrasonic transducer and a second acousto-optical medium; the first or second signal generator is used to generate a driving signal for driving the corresponding first or second acousto-optical deflector, the driving signal is converted into an ultrasonic signal by the first or second ultrasonic transducer after power amplification by the corresponding first or second radio frequency amplifier, and injected into the corresponding first or second acousto-optical medium to form an editable dynamic grating, so as to realize diffraction deflection of the incident light in multiple directions; The laser is used to output linearly polarized light, which is collimated by a collimator and incident on a first acousto-optic deflector along a main optical path, and is divided into one-dimensional multi-path output light beams in the beam splitting direction thereof. The multi-path output light beams are incident on a second acousto-optic deflector, and are diffracted and deflected in multiple directions. Each output light beam is split in the beam splitting direction of a second acousto-optic beam splitting unit to generate a two-dimensional multi-path output light beam. The two-dimensional multi-path output light beams are collimated by a lens group and incident on a focusing lens, forming an array light beam at the focal plane of the focusing lens.

2. The device according to claim 1, characterized in that The lens group comprises a first lens and a second lens which are sequentially arranged along the optical path, and the acousto-optical beam splitting module is located at the front focus of the first lens.

3. The device according to claim 1, characterized in that The beam splitting directions of the first AOD and the second AOD are perpendicular.

4. The device according to claim 1, characterized in that The first acousto-optic medium and the second acousto-optic medium are AOD crystals.

5. A parallel scanning method of an array beam generating device based on an acousto-optic deflector according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: converting the pattern to be processed into a matrix form; S2: Find the rank of the matrix. If the matrix is ​​full rank, scan it row by row or column by column. If the rank is less than the number of rows or columns, execute step S3. S3: Decompose the matrix into multiple sub-matrices and add them together, set the parameters of the corresponding driving signal for this scan according to each sub-matrix, and perform a single scan on each matrix in turn to obtain the pattern to be processed.

6. The method according to claim 5, characterized in that The matrix is ​​decomposed into a plurality of sub-matrices and added, and Boolean matrix decomposition is adopted.

7. The method according to claim 5, characterized in that The pattern is represented by matrix A: The elements in the column vector u correspond to different driving signal input frequencies in the X direction, and the elements in the row vector v correspond to different driving signal input frequencies in the Y direction.

8. An electronic device, characterized in that: include: A computer readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the method according to any one of claims 5 to 7.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to execute the method according to any one of claims 5 to 7.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, the method according to any one of claims 5 to 7 is implemented.

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