An array beam generation device and parallel scanning method based on an acousto-optic deflector

Abstract

This invention discloses an array beam generation device and parallel scanning method based on an acousto-optic deflector, belonging to the field of laser technology. The array beam generation device and parallel scanning method proposed in this invention utilize two acousto-optic beam splitting units to split the laser beam in two different directions, forming a laser beam array. This results in a higher number of points scanned in a single scan and higher energy utilization. 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.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, and more specifically, relates to an array beam generation device and parallel scanning method based on an acousto-optic deflector. Background Technology

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

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

[0004] To improve energy utilization and processing efficiency, components such as microlens arrays, diffractive optical elements (DOE), spatial light modulators (SLM), and acousto-optic modulators (AOM) are used to divide the laser beam into multiple beams more uniformly, thereby achieving parallel laser scanning.

[0005] Microlens arrays consist of multiple micron-sized microlenses arranged in a specific pattern. They can split an incident single laser beam into multiple sub-beams, with each sub-beam corresponding to a microlens, thus enabling parallel scanning. However, they are quite sensitive to the angle and wavelength of the incident light, and require high manufacturing precision. Once fabricated, the beam splitting mode and parameters are basically fixed, limiting their application scenarios.

[0006] Diffractive optical element beam splitting involves creating microstructures on the element surface to diffract incident light, thereby altering the light's propagation direction and intensity distribution, thus splitting the beam. However, it cannot achieve active control of sub-beams, the system parameters are mutually constrained, the cost is high, and the flexibility is poor; furthermore, there are certain energy losses and zero-order interference issues, affecting the uniformity of light intensity.

[0007] Spatial light modulators alter the control voltage across a liquid crystal by inputting different grayscale information, causing the liquid crystal molecules to deflect and thus changing the optical path difference of the incident light. This allows for modulation of the laser's amplitude, phase, polarization state, and other information, achieving flexible beam splitting. However, they have a low damage threshold, slow modulation speed, and can produce coherent artifacts that affect scanning accuracy.

[0008] Acousto-optic modulators utilize the acousto-optic effect. When a laser beam passes through an acousto-optic medium, it undergoes diffraction, thereby splitting a single laser beam into multiple beams. By controlling the driving signal of the acousto-optic modulator, parameters such as the energy, spacing, and direction of each sub-beam can be flexibly adjusted, achieving precise control of the beam and providing technical support for high-speed parallel processing.

[0009] Commonly used laser beam splitting devices suffer from problems such as poor flexibility, low damage threshold, poor scanning accuracy, and low energy utilization. After beam splitting, other scanning devices are usually required to control the scanning path of each sub-beam, resulting in a complex structure and high cost. Furthermore, traditional parallel scanning often uses row-by-row or column-by-column scanning methods, which require too many scans for complex patterns, leading to long scan times and low efficiency. Summary of the Invention

[0010] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an array beam generating device and 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 objectives, according to one aspect of the present invention, an array beam generation device method based on an acousto-optic deflector is provided, comprising: a laser, a collimator, an acousto-optic beam splitter module, a lens group, and a focusing lens arranged sequentially along an optical path; the acousto-optic beam splitter module includes a first acousto-optic beam splitter unit and a second acousto-optic beam splitter unit connected sequentially; the first acousto-optic beam splitter unit includes a first signal generator, a first radio frequency amplifier, and a first acousto-optic deflector, the first acousto-optic deflector including a first ultrasonic transducer and a first acousto-optic medium; the second acousto-optic beam splitter unit includes a second signal generator... The device includes a second radio frequency amplifier and a second acousto-optic deflector. The second acousto-optic deflector includes a second ultrasonic transducer and a second acousto-optic medium. A first or second signal generator is used to generate a driving signal to drive the corresponding first or second acousto-optic deflector. The driving signal is amplified by the corresponding first or second radio frequency amplifier and converted into an ultrasonic signal by the first or second ultrasonic transducer. It is then injected into the corresponding first or second acousto-optic medium to form a grating. By changing the driving signal, the spacing, position and other parameters of the grating are controlled to achieve dynamic editing of the grating, thereby realizing the diffraction deflection of the incident light in multiple directions.

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

[0013] Furthermore, the lens group includes a first lens and a second lens arranged sequentially along the optical path, and the acousto-optic beam splitter module is located at the front focal point of the first lens.

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

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

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

[0017]

[0018] Where A i f i , These represent the amplitude, frequency, and phase of a single-frequency signal, respectively.

[0019] When a collimated beam of frequency v0 is incident on the first acousto-optic deflector, Bragg diffraction will occur, resulting in a certain frequency shift:

[0020] v i d =v0±f 1i

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

[0022] When the i-th diffracted beam from the first acousto-optic deflector is incident on the second acousto-optic deflector, a frequency shift occurs:

[0023]

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

[0025] The beam deflection angle Δθ in each beam splitting direction t It can be represented 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 Let be the frequency difference between the outgoing beam and the incident beam along the beam-splitting direction of the acousto-optic deflector at the t-th moment.

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

[0029]

[0030] Where 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 focused output beam is determined by the frequency of the input signal.

[0032] In an acousto-optic deflector, the cross-sectional area of ​​the ultrasonic wave is the area of ​​the ultrasonic transducer that excites it, and it is equal to the product of its length L and width H, according to the formula for Bragg diffraction efficiency:

[0033]

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

[0035] When the input signal enters the RF amplifier, nonlinear amplification occurs at high power, which leads to a certain degree of distortion in the output signal, nonlinear intermodulation, poor beam uniformity, and additional diffracted 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 intensity of the emitted beam is determined by the amplitude and phase of the input signal. The intensity of the beam can be dynamically edited by changing the amplitude and phase of the input signal.

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

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

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

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

[0041] S2: Calculate the rank of the matrix. If the matrix has a full rank, scan row by row or column by column. If the rank is less than the number of rows or columns, proceed to step S3.

[0042] S3: Decompose the matrix into multiple sub-matrices and add them together. Set the parameters of the driving signal for each sub-matrix for that scan according to the parameters of each sub-matrix. Perform a single scan on each matrix in sequence to obtain the pattern to be processed.

[0043] Optionally, the two acousto-optic deflectors are perpendicular in their beam splitting directions, along the X and Y directions respectively; when the driving signal in the X direction contains a frequency f... xi The single-frequency signal, the Y-direction drive signal contains a frequency of f. yj When a single-frequency signal is received, a deflection angle of Δθ will be generated accordingly. ij The projected angles of the emitted beam in the X and Y directions satisfy the following conditions:

[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 graphic 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 its corresponding element u i Non-zero, if the driving frequency in the Y direction includes f yj Then its corresponding element v j Non-zero elements corresponding to 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 the value of u in A is non-zero, i v j Non-zero, meaning if and only if the driving signal contains a frequency of f. xi and frequency f yj When a single-frequency signal is emitted, a deflection angle of Δθ will be generated. ij The emitted beam can illuminate the corresponding position Δl ij superior;

[0053] According to the property of the rank of a matrix:

[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 matrix A is 1. Therefore, 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. A matrix of rank 1 can always be decomposed into the product of a column vector and a row vector.

[0057] Therefore, the matrix corresponding to the image obtained in a single scan corresponds one-to-one with 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 equal to the rank of the matrix.

[0059] In some embodiments, the laser beam intensity is uniform. In step S1, the parts scanned by the laser are set to 1, and the parts not scanned by the laser are set to 0. The transformed matrix elements are only 0 or 1, which is a Boolean matrix. The corresponding step S3 is Boolean matrix decomposition.

[0060] A m×n =B m×k ×C k×n

[0061] In the formula A m×n B m×k and C k×n All are Boolean matrices;

[0062] Preferably, step S3 can 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 top left corner;

[0064] S32: Find rows or columns with a moderate number of 1s as a base;

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

[0066] S34: Find the number of rows of the covered part in the matrix before rearrangement, set the row corresponding to the first column of matrix B to 1, and the rest of the rows to 0. Similarly, find 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 rest of the columns to 0.

[0067] S35: Subtract the covered portion 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 is ​​completely decomposed. If a small number of points 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 and matrix C k×n The product of the i-th rows is the matrix obtained by the i-th scan, where i = 1, 2, ..., k;

[0071] S42: Calculate the maximum required deflection angle based on the size of the pattern to be scanned, thereby determining the range of input frequency variation. Determine the frequency interval of the input frequency based on the interval of the sub-matrix obtained in each scan in the X and Y directions.

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

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

[0074] S45: The driving signal is obtained by linearly superimposing single-frequency signals, and the driving signal changes with the number of scans;

[0075] Optionally, step S44 can use a random search method, with the peak-to-average power ratio as a constraint condition, to calculate multiple times, and take the one with the smallest peak-to-average power ratio as the optimized phase. Then, the amplitude is optimized according to the collected light spot. After multiple iterations, the relationship between the output power and the amplitude and phase of the input signal at each frequency point of the two-dimensional AOD is obtained, and a data table is made. According to the required light spot intensity, the amplitude and phase corresponding to different frequencies are found, and the input signal can be obtained.

[0076] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following results.

[0077] Beneficial effects:

[0078] 1. The array beam generation device and parallel scanning method of the acousto-optic deflector proposed in this invention utilize two acousto-optic beam splitting units to split the laser beam in two different directions to form a laser beam array. The number of points scanned in a single scan is large, and the energy utilization rate is high. 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 this invention utilizes acousto-optic medium for beam splitting. The angle and intensity of the sub-beams are modulated in real time by the driving signal of the acousto-optic beam splitting module. By setting the amplitude, frequency, and phase of the driving signal according to the matrix parameters obtained from the decomposition and adjusting the input waveform, dynamic control of the laser beam array can be achieved, which is highly flexible.

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

[0081] 4. The laser parallel scanning method proposed in this invention does not require the use of other complex scanning devices, and has a simple structure. Attached Figure Description

[0082] Figure 1 This is a schematic diagram of the structure of a laser parallel scanning device based on acousto-optic beam splitting used in this invention;

[0083] Figure 2 This is a schematic diagram of a single acousto-optic beam splitter module used in this invention;

[0084] Figure 3 This is a schematic diagram of two acousto-optic beam splitting modules forming a beam array in this invention;

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

[0086] Figure 5 This is a schematic diagram illustrating the decomposition of a pattern into multiple single-scannable graphics in an embodiment of the present invention;

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

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

[0089] Reference numerals: 1. Laser, 2. Collimator, 3. Acousto-optic beam splitter 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 Implementation

[0090] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0091] This invention provides a method for generating an array beam based on an acousto-optic deflector, comprising: a laser, a collimator, an acousto-optic beam splitter module, a lens group, and a focusing lens arranged sequentially along an optical path; the acousto-optic beam splitter module includes a first acousto-optic beam splitter unit and a second acousto-optic beam splitter unit connected sequentially; the first acousto-optic beam splitter unit includes a first signal generator, a first radio frequency amplifier, and a first acousto-optic deflector, the first acousto-optic deflector including a first ultrasonic transducer and a first acousto-optic medium; the second acousto-optic beam splitter unit includes a second signal generator, a second radio frequency amplifier, and a second acousto-optic deflector, the second acousto-optic deflector including a second ultrasonic transducer and a second acousto-optic medium; the first or second signal generator is used to generate a driving signal to drive the corresponding first or second acousto-optic deflector, the driving signal is amplified by the corresponding first or second radio frequency amplifier and 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 an editable dynamic grating, thereby realizing the diffraction deflection of incident light in multiple directions;

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

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

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

[0095] S2: Calculate the rank of the matrix. If the matrix has a full rank, scan row by row or column by column. If the rank is less than the number of rows or columns, proceed to step S3.

[0096] S3: Decompose the matrix into multiple sub-matrices and add them together. Set the parameters of the driving signal for each sub-matrix for that scan according to the parameters of each sub-matrix. Perform a single scan on each matrix in sequence to obtain the pattern to be processed.

[0097] The following description, in conjunction with preferred embodiments, illustrates the content involved in the above embodiments.

[0098] Example 1

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

[0100] The linearly polarized light output from the laser 1 is collimated by the collimator 2 and then incident on the acousto-optic beam splitter module 3 along the main optical path;

[0101] The two acousto-optic beam splitting modules 3 include two sets 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-optic deflector 31 and a second acousto-optic deflector 32.

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

[0103] After beam splitting by the acousto-optic beam splitter module 3, the resulting sub-beam array is amplified by the 4F system composed of two lenses in module 4.

[0104] The focusing lens 5 is used to focus multiple laser beams into an array, and scan a beam array on the scanning plane 6.

[0105] like Figure 2 The diagram shown is a schematic of the first acousto-optic beam splitting unit in an embodiment of the present invention. The first signal generator 35 is used to generate a driving signal, which is a linear superposition of 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, thereby realizing the beam splitting of the incident laser.

[0106] like Figure 3 The diagram shows a beam array formed by two acousto-optic beam splitting modules in this invention. The first signal generator 35 generates a driving signal in the Y direction, which is amplified by the first radio frequency amplifier 33 and then injected into the first acousto-optic deflector 31, causing the laser beam to split in the Y direction. The second signal generator 36 generates a driving signal in the X direction, which is amplified by the second radio frequency amplifier 34 and then injected into the second acousto-optic deflector 32, causing the laser beam to split in the X direction. When the X-direction driving signal contains a frequency f... xi The single-frequency signal, the Y-direction drive signal contains a frequency of f. yj When a single-frequency signal is received, a deflection angle of Δθ will be generated accordingly. ij The emitted beam.

[0107] Figure 4 In this embodiment, A represents the pattern to be scanned. The specific steps for parallel laser scanning based on a beam array generated by an acousto-optic deflector and matrix decomposition include:

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

[0109] In this embodiment, the laser beam intensity is uniform, with areas processed by laser set to 1 and areas without laser processing set to 0. This translates to matrix elements being either 0 or 1, meaning the pattern can be converted into a Boolean matrix.

[0110]

[0111] S2: Calculate the rank of the matrix and determine the minimum number of scans required to decompose it. If the matrix is ​​almost full rank, use a row-by-row or column-by-column scan method. If its rank is significantly less than the number of rows and columns, proceed to step S3.

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

[0113] S3: Decompose the matrix into multiple matrices that can be added 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 used, and the specific steps are as follows:

[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 top left corner;

[0117] S32: Find rows or columns with a moderate number of 1s as a base;

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

[0119] S34: Find the number of rows of the covered part in the matrix before rearrangement, set the row corresponding to the first column of matrix B to 1, and the rest of the rows to 0. Similarly, find 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 rest of the columns to 0.

[0120] S35: Subtract the covered portion 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 is ​​completely decomposed. If a small number of points 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: Set parameters for each submatrix, specifically including:

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

[0128] For example, the matrix scanned in the first scan is B. 11×5 The first column and C 5×11 Multiply the first row:

[0129]

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

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

[0132] S42: Calculate the maximum required deflection angle based on the size of the pattern to be scanned, thereby determining the range of input frequency variation. Determine the frequency interval of the input frequency based on the interval of the sub-matrix obtained in each scan in the X and Y directions.

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

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

[0135] Step S44 can use a random search method, with the peak-to-average power ratio (PAPR) as a constraint condition. After multiple calculations, the PAPR with the smallest PAPR is taken as the optimized phase. Then, the amplitude is optimized based on the collected light spot. After multiple iterations, the relationship between the output power and the amplitude and phase of the input signal at each frequency point of the two-dimensional AOD is obtained. A data table is created, and the amplitude and phase corresponding to different frequencies are found according to the required light spot intensity, so that the input signal can be obtained.

[0136] In this embodiment, the light spot intensity is consistent and uniform. By selecting an appropriate output power, the amplitude and phase corresponding to different frequencies are found in the data table.

[0137] S45: The driving signal is obtained by linearly superimposing single-frequency signals, and the driving signal changes with the number of scans.

[0138] like Figure 6 This is a schematic diagram illustrating the process of using matrix decomposition to determine the input frequency corresponding to each beam array and performing parallel scanning.

[0139] like Figure 4 B to F in the diagram represent the five scanning processes in this embodiment, and the black dots represent the laser beam array generated in that scan.

[0140] Example 2

[0141] like Figure 7 In this embodiment, A represents the pattern to be scanned. In this embodiment, the pattern has grayscale variations, and the required laser beam array intensity is not uniform. 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 for 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] Based on the grayscale of the pattern, the matrix elements at different positions take different values, and the magnitude of the value is proportional to the required laser spot intensity.

[0145]

[0146] S2: Calculate the rank of the matrix and determine the minimum number of scans required to decompose it. If the matrix is ​​almost full rank, use a row-by-row or column-by-column scan method. If its rank is significantly less than the number of rows and columns, proceed to step S3.

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

[0148] S3: Decompose the matrix into multiple matrices that can be added 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: Set parameters for each submatrix, specifically including:

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

[0156] The matrix decomposition results show that it can be divided into 3 scans.

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

[0158] S42: Calculate the maximum required deflection angle based on the size of the pattern to be scanned, thereby determining the range of input frequency variation. Determine the frequency interval of the input frequency based on the interval of the sub-matrix obtained in each scan in the X and Y directions.

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

[0160] S44: Find the optimal amplitude and phase for each frequency so that the intensity of the emitted beam spot is proportional to the matrix element values.

[0161] Based on the required spot intensity at different frequency points, calculate the output power of the emitted beam at different frequencies after beam splitting by the acousto-optic medium. Find the amplitude and phase corresponding to the required output power at that frequency in the table to obtain the parameters of the input signal.

[0162] S45: The driving signal is obtained by linearly superimposing single-frequency signals, and the driving signal changes with the number of scans.

[0163] In some embodiments, the acousto-optic beam splitter module may also be fitted with lenses so that the beam splitting direction is not perpendicular.

[0164] In some embodiments, the laser beam intensity is not uniform, and a grayscale pattern is scanned. That is, in step S44, the intensity of different emitted light spots is different, and the corresponding amplitude and phase are looked up in the table according to the intensity of the output light spot.

[0165] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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 has been described in detail above with reference to the embodiments, but it should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A parallel scanning method for an array beam generation device based on an acousto-optic deflector, the array beam generation device comprising a laser, a collimator, an acousto-optic beam splitter module, a lens group, and a focusing lens arranged sequentially along an optical path; the acousto-optic beam splitter module comprising a first acousto-optic beam splitter unit and a second acousto-optic beam splitter unit connected sequentially; the first acousto-optic beam splitter unit comprising a first signal generator, a first radio frequency amplifier, and a first acousto-optic deflector, the first acousto-optic deflector comprising a first ultrasonic transducer and a first acousto-optic medium; the second acousto-optic beam splitter unit comprising a second signal generator, a second radio frequency amplifier, and a second acousto-optic deflector, the second acousto-optic deflector comprising a second ultrasonic transducer and a second acousto-optic medium; the first or second signal generator is used to generate a driving signal to drive the corresponding first or second acousto-optic deflector, the driving signal is amplified by the corresponding first or second radio frequency amplifier and 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 an editable dynamic grating, thereby realizing the diffraction deflection of incident light in multiple directions; The laser is used to output linearly polarized light. After being collimated by a collimator, it is incident on the first acousto-optic deflector along the main optical path. It is split into one-dimensional multiple output beams in its beam splitting direction. The multiple output beams are incident on the second acousto-optic deflector and diffracted in multiple directions. Each output beam is split in the beam splitting direction of the second acousto-optic beam splitting unit to generate two-dimensional multiple output beams. The two-dimensional multiple output beams are collimated by a lens group and then incident on the focusing lens to form an array beam at the focal plane of the focusing lens. Its features are, Includes the following steps: S1: Convert the pattern to be processed into a matrix form; S2: Calculate the rank of the matrix. If the matrix has a full rank, scan row by row or column by column. If the rank is less than the number of rows or columns, proceed to step S3. S3: Decompose the matrix into multiple sub-matrices and add them together. Set the parameters of the driving signal for each sub-matrix for that scan according to the parameters of each sub-matrix. Perform a single scan on each matrix in sequence to obtain the pattern to be processed.

2. The method according to claim 1, characterized in that, The matrix is ​​decomposed into multiple submatrices and then added together, using Boolean matrix decomposition.

3. The method according to claim 1, characterized in that, The pattern is represented by matrix A: Where column vectors The elements in the middle correspond to different driving signal input frequencies in the X direction, and the row vectors are... The elements in the middle correspond to different driving signal input frequencies in the Y direction.

4. The method according to claim 1, characterized in that, The lens group includes a first lens and a second lens arranged sequentially along the optical path, and the acousto-optic beam splitter module is located at the front focal point of the first lens.

5. The method according to claim 1, characterized in that, The beam splitting directions of the first and second acousto-optic deflectors are perpendicular.

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

7. An electronic device, characterized in that, include: Computer-readable storage media and processors; The computer-readable storage medium is used to store executable instructions; The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the method as described in any one of claims 1-6.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a processor to perform the method as described in any one of claims 1-6.

9. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the method as described in any one of claims 1-6.

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