A phase shifter calibration method and calibration apparatus

Abstract

The application discloses a phase shifter calibration method and a calibration device, and relates to the field of optical detection instruments. The phase shifter calibration device comprises an optical interference detection module and a control module, the control module comprises a controller and a processor, and the controller is connected with the phase shifter. A preset voltage sequence is applied to the phase shifter, and an interference fringe pattern under each voltage is collected by the optical interference detection module; actual phase shifts are obtained based on the fringe pattern, and actual phase shift slopes are calculated. If the actual phase shift slope does not meet preset requirements, a slope ratio is determined according to the ratio of a target phase shift slope to the actual phase shift slope and is sent to the controller. The controller generates a new voltage sequence in combination with the slope ratio, a preset voltage multiplication coefficient and the preset voltage sequence, and the new voltage sequence is re-applied to the phase shifter for repeated adjustment. When the slope meets the requirements, the calibration is completed. The method directly collects the fringe pattern by using an interference system, does not need additional sensing elements or external interferometers, simplifies the system structure, realizes automatic calibration, and improves calibration efficiency and accuracy.

Description

Technical Field

[0001] This invention relates to the field of optical testing instruments, and in particular to a phase shifter calibration method and calibration device. Background Technology

[0002] Interferometric testing is widely used in the high-precision surface shape inspection of optical components. Phase-Shifting Interferometry (PSI) measures the changes in interference fringes caused by the change in optical path between the reference light and the measurement light. Piezoelectric Zirconate Titanate (PZT) mechanical phase shifters are key components that provide phase shift in optical detection systems, and the accurate calibration of their phase shift directly affects the performance of the detection system.

[0003] Existing PZT phase shifter calibration and correction methods typically require manual measurement and adjustment using measuring equipment (such as external interferometers) and sensing elements (such as capacitive sensors), or they may only perform calibration without correction, resulting in reduced efficiency and accuracy of phase shifter calibration. Furthermore, the introduction of external equipment increases the complexity of the system.

[0004] Therefore, improving the efficiency and accuracy of phase shifter calibration, as well as reducing the complexity of the calibration system, are technical problems that urgently need to be solved by those in the field. Summary of the Invention

[0005] The purpose of this invention is to provide a phase shifter calibration method and calibration device to solve the problems of low efficiency and accuracy in phase shifter calibration and high complexity of the calibration system.

[0006] To solve the above-mentioned technical problems, the present invention provides a phase shifter calibration method, applied to a phase shifter calibration device, the phase shifter calibration device including an optical interferometry detection module and a control module; the control module includes a controller and a processor; the controller is connected to the phase shifter in the optical interferometry detection module; the method includes: The controller applies a preset voltage sequence to the phase shifter, and the optical interference detection module acquires the interference fringe pattern at each voltage in the preset voltage sequence. The actual phase shift of the phase shifter is obtained based on the interference fringe pattern at each voltage, and the actual phase shift slope of the phase shifter is determined based on the actual phase shift and the voltage. If the actual phase shift slope is detected to meet the preset phase shift slope requirement, then the calibration of the phase shifter is determined to be complete. If the actual phase shift slope is detected to not meet the preset phase shift slope requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; the slope ratio is transmitted to the controller so that the controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier coefficient and the preset voltage sequence, and applies the current voltage sequence as the new preset voltage sequence to the phase shifter.

[0007] Optionally, before determining the actual phase shift slope of the phase shifter based on the actual phase shift and voltage of the phase shifter, the method further includes: Obtain the target phase shift; If the difference between the actual phase shift and the target phase shift is detected to be greater than the difference threshold, then proceed to the step of determining the actual phase shift slope of the phase shifter based on the actual phase shift and voltage of the phase shifter; Conversely, the process ends.

[0008] Optionally, in the case where a single lens is driven by a phase shifter, the preset phase shift slope requirement is that the difference between the actual phase shift slope and the target phase shift slope is less than a first preset value; In the case where multiple phase shifters drive a single lens, the preset phase shift slope requirement includes a first preset requirement and / or a second preset requirement; The first preset requirement is that the difference between the actual phase shift slopes of any two phase shifters is less than the second preset value. The second preset requirement is that the difference between the total actual phase shift slope corresponding to all phase shifters and the target phase shift slope is less than the third preset value.

[0009] Optionally, the phase shifter calibration device includes multiple controllers, and each controller is connected to a phase shifter in a one-to-one correspondence, with all controllers connected to the processor; the preset phase shift slope requirement includes the first preset requirement and the second preset requirement; Determining the completion of phase shifter calibration includes: If the actual phase shift slope is detected to meet the first preset requirement, it is determined whether the actual phase shift slope meets the second preset requirement; If so, then the calibration of the phase shifter is complete.

[0010] Optionally, if, after detecting that the actual phase shift slope meets the first preset requirement, the actual phase shift slope does not meet the second preset requirement, obtaining the ratio between the target phase shift slope and the actual phase shift slope to determine the slope ratio includes: The ratio between the target phase shift slope and the total actual phase shift slope corresponding to all phase shifters is obtained to determine the slope ratio. The controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, including: The product of the slope ratio and the preset total voltage multiplier coefficient is obtained to determine the new total voltage multiplier coefficient; The current voltage multiplier is determined based on the product of the new total voltage multiplier and the preset voltage multiplier. The current voltage sequence is determined based on the product of the current voltage multiplier and the preset voltage sequence.

[0011] Optionally, it further includes: if the actual phase shift slope is detected to not meet the first preset requirement, obtaining the ratio between the target phase shift slope and the actual phase shift slope to determine the slope ratio includes: For each phase shifter, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; The controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, including: Obtain the product of the slope ratio and the preset voltage multiplier coefficient to determine the new preset voltage multiplier coefficient; The current voltage multiplier is determined by the product of the new preset voltage multiplier and the preset total voltage multiplier. The current voltage sequence is determined based on the product of the current voltage multiplier and the preset voltage sequence.

[0012] Optionally, it also includes: Obtain the number of new preset voltage sequences; If the number of new preset voltage sequences detected is less than the threshold, the calibration of the phase shifter is considered complete.

[0013] Optionally, the controller further includes, before applying a new preset voltage sequence to the phase shifter: Obtain the operating voltage range of the phase shifter; If all voltages in the new preset voltage sequence are detected to be within the operating voltage range, then proceed to the step of applying the new preset voltage sequence to the phase shifter; If a voltage outside the operating voltage range is detected in a new preset voltage sequence, a prompt message indicating that the voltage sequence is out of range is output.

[0014] Optionally, before applying a preset voltage sequence to the phase shifter via the controller, the method further includes: Set the preset voltage multiplier coefficient, the operating voltage range, the threshold, and the target phase shift slope for the phase shifter; The preset voltage multiplier, the operating voltage range, the threshold, and the target phase shift slope are transmitted to the controller.

[0015] To address the aforementioned technical problems, the present invention also provides a phase shifter calibration device, comprising an optical interferometry detection module and a control module; the control module includes a controller and a processor; the controller is connected to the phase shifter in the optical interferometry detection module; The controller is configured to apply a preset voltage sequence to the phase shifter, and after receiving the slope ratio sent by the processor, determine the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, and apply the current voltage sequence as a new preset voltage sequence to the phase shifter. The optical interference detection module is used to acquire interference fringe patterns at each voltage in the preset voltage sequence; The processor is configured to acquire interference fringe patterns at each voltage in the preset voltage sequence via an optical interference detection module; obtain the actual phase shift of the phase shifter based on the interference fringe patterns at each voltage, and determine the actual phase shift slope of the phase shifter based on the actual phase shift and the voltage; if the actual phase shift slope is detected to meet the preset phase shift slope requirement, the calibration of the phase shifter is determined to be complete; if the actual phase shift slope is detected to not meet the preset phase shift slope requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; and the slope ratio is transmitted to the controller.

[0016] The phase shifter calibration method provided by this invention is applied to a phase shifter calibration device, which includes an optical interferometry detection module and a control module. The control module includes a controller and a processor. The controller is connected to the phase shifter in the optical interferometry detection module. The processor first applies a preset voltage sequence to the phase shifter through the controller, and then acquires interference fringe patterns at each voltage in the preset voltage sequence through the optical interferometry detection module. After acquiring the interference fringe patterns, the actual phase shift of the phase shifter is obtained based on the interference fringe patterns at each voltage, and the actual phase shift slope of the phase shifter is determined based on the actual phase shift and the voltage. When it is detected that the actual phase shift slope does not meet the preset phase shift slope requirement, the slope ratio is determined based on the ratio between the target phase shift slope and the actual phase shift slope, and finally the slope ratio is transmitted to the controller. After receiving the slope ratio from the processor, the controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence. This current voltage sequence is then used as the new preset voltage sequence, and applied to the phase shifter, thus adjusting the phase shifter voltage. This process is repeated until the actual phase shift slope meets the preset phase shift slope requirement, at which point the phase shifter calibration is considered complete. During the phase shifter calibration, the interference fringe pattern is directly acquired using the interferometric system (i.e., the optical interferometry detection module) where the phase shifter is located to measure the actual phase shift. This eliminates the need for additional sensing elements (such as capacitive sensors) or reliance on external interferometers, reducing the complexity and cost of the calibration system. Furthermore, the controller and processor automatically adjust the voltage applied to the phase shifter to ensure the actual phase shift slope meets the preset phase shift slope requirement, thus completing the calibration. The entire calibration process requires no manual intervention, significantly improving calibration efficiency and accuracy.

[0017] In addition, the present invention also provides a phase shifter calibration device, which has the same or corresponding technical features as the phase shifter calibration method mentioned above, and has the same effect. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a phase shifter calibration device provided in an embodiment of the present invention; Figure 2 A structural diagram of a phase shifter calibration device provided in an embodiment of the present invention; Figure 3 A flowchart of a phase shifter calibration method provided in an embodiment of the present invention; Figure 4This is a flowchart illustrating a calibration process in a scenario where three phase shifters drive a single lens, as provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0021] The core of this invention is to provide a phase shifter calibration method and calibration device to solve the problems of low efficiency and accuracy in phase shifter calibration and high complexity of the calibration system.

[0022] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The phase shifter calibration method provided by the present invention is applied to a phase shifter calibration device. Figure 1 This is a schematic diagram of a phase shifter calibration device provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the phase shifter calibration device includes an optical interferometry detection module 100 and a control module 200. The control module 200 includes a controller and a processor. The controller is connected to the phase shifter in the optical interferometry detection module 100, and the processor is connected to the controller. In practice, a single phase shifter can drive a single lens, or multiple phase shifters can drive a single lens. When multiple phase shifters drive a single lens, the phase shifter calibration device includes multiple controllers, and each controller is connected to a phase shifter in a one-to-one correspondence. All controllers are connected to the processor. The calibration device can be divided into two main parts: an optical interferometry detection module and a closed-loop control correction module. The optical interferometry detection module includes a coherent light source, optical elements, and a detector. The closed-loop control correction module includes an interferometry module, a controller, and a processor.

[0023] The optical inspection module includes: a coherent light source: a laser (which can be a semiconductor / fiber laser), collimated / shaped; a beam splitter and imaging link: a beam splitter, a reference mirror, a mirror under test, and an imaging / focusing lens; a phase modulation actuator: a phase shifter (reference arm or object arm mirror assembly); a detector: a charge-coupled device (CCD) / complementary metal-oxide-semiconductor (CMOS), supporting external triggering and high-speed frame acquisition; and a synchronization signal: a trigger and timing interface to ensure application and acquisition alignment.

[0024] The closed-loop control correction module includes: Controller: Multi-channel Digital-to-Analog Converter (DAC), power amplification and protection circuitry, supporting voltage multiplier factor distribution. Processor (for computer / embedded system): Performs stripe preprocessing, phase calculation, error analysis, and parameter updates. Data Bus: Command control (serial port / Controller Area Network (CAN) / Ethernet). Software Stack: Parallel acquisition thread, calculation thread, and control thread, including logging and exception handling.

[0025] Figure 2 A structural diagram of a phase shifter calibration device provided in an embodiment of the present invention is shown below. Figure 2 As shown, the optical detection module includes a coherent light source 1, a collimating lens 2, a beam splitter 3, a focusing lens 4, a driver 5, a reference mirror 6, a test mirror 7, an imaging lens 8, and a detector 9; the control module includes a processor 10 and a controller 11. The coherent light source is a laser. The laser can be a semiconductor / fiber laser, providing stable incident light for the entire interferometric system. The collimating lens is used to collimate or focus the laser beam, ensuring the beam has a suitable spot and wavefront when it enters the beam splitter. The beam splitter divides the incident light into two paths: one as a reference beam and the other as a measurement beam. The focusing lens focuses the measurement beam onto the surface of the test object while collecting reflected light. The controller is connected to the phase shifter in the optical interferometric detection module, specifically through the driver. The driver is responsible for precisely controlling the displacement of the reference mirror or the test object, introducing a nanometer-level phase shift. The reference mirror is mounted on the driver, forming a reference arm optical path. The test mirror is the object being measured; its surface morphology or displacement information modulates the phase of the reflected light. An imaging lens is used to image the fringes resulting from the interference of two beams onto a detector. The detector receives the interference fringes and converts them into digital signals for subsequent processing by a processor. The processor, which can be a computer, processes the data acquired by the detector, including phase calculation and slope scaling. The controller provides precise voltage signals to the driver to achieve phase shift control and interacts with the processor in a closed-loop manner.

[0026] Based on the above-mentioned phase shifter calibration device, Figure 3 A flowchart of a phase shifter calibration method provided in an embodiment of the present invention is shown below. Figure 3 As shown, the method includes: S10: Apply a preset voltage sequence to the phase shifter through the controller, and acquire the interference fringe pattern of each voltage in the preset voltage sequence through the optical interference detection module; S11: Obtain the actual phase shift of the phase shifter based on the interference fringe pattern under each voltage, and determine the actual phase shift slope of the phase shifter based on the actual phase shift and voltage; S12: Determine whether the actual phase shift slope meets the preset phase shift slope requirement; if yes, proceed to step S13; if no, proceed to step S14. S13: Confirm that the phase shifter calibration is complete; S14: Obtain the ratio between the target phase shift slope and the actual phase shift slope to determine the slope ratio; transmit the slope ratio to the controller so that the controller can determine the current voltage sequence based on the slope ratio, the preset voltage multiplier coefficient and the preset voltage sequence, and apply the new preset voltage sequence to the phase shifter as the new preset voltage sequence.

[0027] After step S14, you can return to step S10.

[0028] Before applying a preset voltage sequence to the phase shifter via the controller, the following is also included: Set the preset voltage multiplier, operating voltage range, threshold (referred to as threshold) representing the number of times the voltage sequence is changed, and target phase shift slope for the phase shifter; The preset voltage multiplier, operating voltage range, threshold, and target phase shift slope are transmitted to the controller.

[0029] For the preset voltage multiplier coefficient Operating voltage range A threshold representing the number of times the voltage sequence is changed (also known as the maximum number of iterations). and target phase shift slope No limitation is set; the specific voltage range can be determined based on the actual situation. For example, the operating voltage range can be determined based on the operating range of the specific phase shifter. The voltage scaling factor characterizes the scaling of each voltage in the voltage sequence. When driving a single lens for a single phase shifter, the preset voltage scaling factor is the voltage scaling factor of that phase shifter. When multiple phase shifters drive a single lens, the preset voltage magnification factor is the voltage magnification factor corresponding to each phase shifter. And the total voltage multiplier corresponding to all phase shifters (i.e., the preset total voltage multiplier). ).

[0030] After transmitting the preset voltage multiplier, operating voltage range, threshold, and target phase shift slope to the controller, the controller applies a preset voltage sequence to the phase shifter, and the optical interferometry detection module acquires the interference fringe patterns at each voltage in the preset voltage sequence. When a single phase shifter drives a single lens, the preset voltage sequence is applied to that phase shifter, and each voltage point triggers a camera acquisition; when multiple phase shifters drive a single lens, the preset voltage sequence is applied to each phase shifter in parallel, and each voltage point triggers a camera acquisition.

[0031] The actual phase shift of the phase shifter is obtained based on the interference fringe patterns at various voltages, and the actual phase shift slope is determined based on the actual phase shift and voltage. This involves interference fringe processing and phase calculation. For phase calculation, a multi-step phase shift relative to the fringe pattern is used to obtain the actual phase shift. For phase shift slope estimation, a linear regression is used to fit the phase-voltage curve for each path in a sequence to obtain the measured phase shift slope.

[0032] After obtaining the measured phase shift slope, in order to reduce the workload during calibration, some embodiments further include the following steps before determining the actual phase shift slope of the phase shifter based on the actual phase shift and voltage of the phase shifter: Obtain the target phase shift; If the difference between the actual phase shift and the target phase shift is detected to be greater than the difference threshold, then proceed to the step of determining the actual phase shift slope of the phase shifter based on the actual phase shift and voltage of the phase shifter; Conversely, the process ends.

[0033] That is, the target phase shift can be set in advance in the processor. The target phase shift and the difference threshold are not limited and are determined according to the actual situation. When the difference between the actual phase shift and the target phase shift is less than or equal to the difference threshold, the process ends directly, that is, the phase shifter calibration is completed; when the difference between the actual phase shift and the target phase shift is greater than the difference threshold, the subsequent preset voltage sequence adjustment process is carried out, that is, the phase shift correction process.

[0034] After obtaining the actual phase shift of the phase shifter based on the interference fringe patterns at various voltages, the actual phase shift slope of the phase shifter is determined based on the actual phase shift and voltage. That is, the actual phase shift slope is obtained based on the phase-voltage curve.

[0035] Determine whether the actual phase shift slope meets the preset phase shift slope requirement. When a single phase shifter drives a single lens, the preset phase shift slope requirement is that the difference between the actual phase shift slope and the target phase shift slope is less than a first preset value. When multiple phase shifters drive a single lens, the preset phase shift slope requirement includes a first preset requirement and / or a second preset requirement. The first preset requirement is that the difference between the actual phase shift slopes corresponding to any two phase shifters is less than a second preset value; the second preset requirement is that the difference between the total actual phase shift slope corresponding to all phase shifters and the target phase shift slope is less than a third preset value. The first, second, and third preset values ​​are not limited; for example, they can be set to 0.1. That is, the second preset requirement is... ,and ; and Indicates different phase shifters, and This represents the actual phase shift slope of any two paths. This represents the total actual phase shift slope corresponding to all phase shifters. This represents the target phase shift slope corresponding to all phase shifters. Specifically, the first preset requirement indicates that the actual phase shift slope approaches the target phase shift slope; the second preset requirement indicates that the ratio of the phase shift slopes of each channel reaches approximately 1:1:1; and the third preset requirement indicates that the ratio of the total slope of the multiple channels approaches the target phase shift slope.

[0036] For a scenario where a single phase shifter drives a single lens, if the actual phase shift slope is detected to be less than a first preset value (the difference between the actual and target phase shift slopes is less than a first preset value), then the ratio between the target and actual phase shift slopes is obtained to determine the slope ratio; this slope ratio is then transmitted to the controller. Slope Ratio The expression is: ; This represents the phase shift slope of the phase shifter corresponding to the controller. After receiving the slope ratio sent by the processor, the controller determines the current voltage sequence based on the product of the slope ratio, a preset voltage multiplier, and a preset voltage sequence. The current voltage sequence is then used as the new preset voltage sequence, and this new preset voltage sequence is applied to the phase shifter. This calibration process is repeated until the actual phase shift slope is found to satisfy the condition that the difference between the actual phase shift slope and the target phase shift slope is less than a first preset value, at which point the calibration is considered complete.

[0037] For scenarios where multiple phase shifters drive a single lens, determining the calibration of the phase shifters includes: If the actual phase shift slope is found to meet the first preset requirement, it is determined whether the actual phase shift slope meets the second preset requirement. If so, then the calibration of the phase shifter is complete.

[0038] After detecting that the actual phase shift slope meets the first preset requirement, and if the actual phase shift slope does not meet the second preset requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio, including: The ratio between the target phase shift slope and the total actual phase shift slope corresponding to all phase shifters is obtained to determine the slope ratio.

[0039] The controller determines the current voltage sequence based on the slope ratio, preset voltage multiplier, and preset voltage sequence, including: Obtain the product of the slope ratio and the preset total voltage multiplier to determine the new total voltage multiplier. The current voltage multiplier is determined based on the product of the new total voltage multiplier and the preset voltage multiplier. The current voltage sequence is determined by multiplying the current voltage multiplier and the preset voltage sequence.

[0040] In a scenario where multiple phase shifters drive a single lens, if the actual phase shift slope meets the first preset requirement, but the detected actual phase shift slope does not meet the second preset requirement, then the current voltage sequence = Preset voltage sequence. It represents the ratio between the target phase shift slope and the total actual phase shift slope corresponding to all phase shifters, resulting in a slope ratio.

[0041] The current voltage sequence is used as the new preset voltage sequence. The new preset voltage sequence is applied to the phase shifter, and the above calibration process is repeated until the actual phase shift slope is detected to meet the first preset requirement and the second preset requirement, at which point the calibration is determined to be complete.

[0042] To enable those skilled in the art to better understand the calibration process in a scenario where the actual phase shift slope does not meet the second preset requirement after the first preset requirement has been met, the process is illustrated below using a three-phase shifter driving a single lens as an example. The first phase shifter is connected to the first controller, the second phase shifter is connected to the second controller, and the third phase shifter is connected to the third controller; the first, second, and third controllers are all connected to the same processor.

[0043] The processor sends a preset voltage sequence and a preset voltage multiplier coefficient to the first controller, the second controller, and the third controller (the preset voltage multiplier coefficient sent to the first controller is used as...). This indicates that the preset voltage multiplier coefficient sent to the second controller is used... This indicates that the preset voltage multiplier coefficient sent to the third controller is used... (This indicates that a preset voltage sequence is stored in the first controller, the second controller, and the third controller).

[0044] After obtaining the slope ratio, the processor transmits the slope ratio to the first controller, the second controller, and the third controller, respectively. In the first controller, the current voltage sequence = Preset voltage sequence; in the second controller, the current voltage sequence = Preset voltage sequence; in the third controller, the current voltage sequence = A preset voltage sequence is established. After calculating the current voltage sequence, each controller sends the current voltage sequence to its corresponding phase shifter. The calibration process is repeated until the actual phase shift slope meets the first and second preset requirements, at which point the calibration is considered complete.

[0045] In addition to the calibration process described above for satisfying the first preset requirement but not the second preset requirement, in practice, scenarios where the first preset requirement is not met may also occur. To correct the phase shift in such scenarios, in some embodiments, when the actual phase shift slope is detected to not meet the first preset requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio, including: For each phase shifter, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio.

[0046] The controller determines the current voltage sequence based on the slope ratio, preset voltage multiplier, and preset voltage sequence, including: Obtain the product of the slope ratio and the preset voltage multiplier to determine the new preset voltage multiplier. The current voltage multiplier is determined by the product of the new preset voltage multiplier and the preset total voltage multiplier. The current voltage sequence is determined by multiplying the current voltage multiplier and the preset voltage sequence.

[0047] In a scenario where multiple phase shifters drive a single lens, the current voltage sequence = Preset voltage sequence. Use the current voltage sequence as the new preset voltage sequence, apply the new preset voltage sequence to the phase shifter, and repeat the above calibration process until the actual phase shift slope is detected to meet the first preset requirement and the second preset requirement, then the calibration is considered complete.

[0048] To help those skilled in the art better understand the calibration process in scenarios where the first preset requirement is not met, the following example will still use three phase shifters driving a single lens, i.e., a three-way phase shifter. The actual phase shift slope of the first controller is used as... The target phase shift slope is represented by... To represent the slope ratio, use Indicated; the actual phase shift slope of the second controller is expressed as The target phase shift slope is represented by... To represent the slope ratio, use Indicates; the actual phase shift slope of the third controller is expressed as The target phase shift slope is represented by... Indicates; slope ratio is expressed as The processor sends a preset voltage sequence and a preset voltage multiplier coefficient to the first controller, second controller, and third controller (the preset voltage multiplier coefficient sent to the first controller is represented by...). This indicates that the preset voltage multiplier coefficient sent to the second controller is used... This indicates that the preset voltage multiplier coefficient sent to the third controller is used... (This indicates that a preset voltage sequence is stored in the first controller, the second controller, and the third controller).

[0049] After obtaining the slope ratio, the processor transmits the slope ratio to the first controller, the second controller, and the third controller, respectively. In the first controller, the current voltage sequence = Preset voltage sequence; in the second controller, the current voltage sequence = Preset voltage sequence; in the third controller, the current voltage sequence = A preset voltage sequence is established. After calculating the current voltage sequence, each controller sends the current voltage sequence to its corresponding phase shifter. The calibration process is repeated until the actual phase shift slope meets the first and second preset requirements, at which point the calibration is considered complete.

[0050] It is worth noting that in the above process, for scenarios where multiple phase shifters drive a single lens, it is first determined whether the first preset requirement is met, and then whether the second preset requirement is met. In practice, it is also possible to first determine whether the second preset requirement is met, and then determine whether the first preset requirement is met.

[0051] Besides the aforementioned method of determining calibration completion based on slope ratio, calibration can also be determined by whether the number of iterations reaches a threshold. Specifically, the phase shifter calibration method further includes: obtaining the number of new preset voltage sequences; if the number of new preset voltage sequences is less than the threshold, then the phase shifter calibration is determined to be complete. That is, the number of new preset voltage sequences represents the number of iterations (i.e., the number of voltage sequence adjustments), thus realizing the determination of calibration completion.

[0052] After obtaining a new preset voltage sequence, if any voltage in the sequence exceeds the operating voltage range of the phase shifter, the phase shifter will malfunction. Therefore, to ensure the phase shifter functions correctly, in some embodiments, the controller further includes the following step before applying the new preset voltage sequence to the phase shifter: Obtain the operating voltage range of the phase shifter; If all voltages in the new preset voltage sequence are detected to be within the operating voltage range, then proceed to the step of applying the new preset voltage sequence to the phase shifter; If a voltage outside the operating voltage range is detected in a new preset voltage sequence, a prompt message indicating that the voltage sequence is out of range will be output.

[0053] In this embodiment, the voltage sequence is checked in advance to avoid applying voltages outside the operating range to the phase shifter as much as possible, thereby reducing the possibility of damage to the phase shifter.

[0054] The calibration process for a single phase shifter driving a single lens and for multiple phase shifters driving a single lens, as described above, is now explained below with reference to the accompanying drawings and specific embodiments.

[0055] Figure 4 A flowchart of a calibration process in a scenario where three phase shifters drive a single lens, as provided in an embodiment of the present invention, is shown below. Figure 4 As shown, the method includes: S15: Initialize the three-channel voltage multiplier coefficient; S16: Apply three-channel output voltage; S17: The detector collects stripe pattern information; S18: Solve the phase shift of the three phase shifters and calculate the actual phase shift slope of the three phase shifters; S19: Determine whether the actual phase shift slopes of the three paths are close; if yes, proceed to step S20; if no, proceed to step S24. S20: Determine whether the actual phase shift slope is close to the target phase shift slope; if yes, proceed to step S21; if no, proceed to step S22. S21: Calibration complete; S22: Calculate the ratio of the total phase shift slope of the three paths to the target phase shift slope to obtain the slope ratio; S23: Transmit the slope ratio to the control board to modify the three-channel voltage multiplier coefficient; return to step S16; S24: Calculate the slope ratios of the three paths respectively; S25: Transmit the calculated slope ratios of the three channels to the control board to modify the voltage multiplier coefficients of the three channels, and return to step S16.

[0056] The phase shifter calibration method provided by this invention directly utilizes the inherent characteristics of the interferometric system (relying entirely on interference fringe feedback), avoiding additional sensors. It is a non-contact and simplified system, reducing system complexity and cost. Through iterative optimization, it reduces environmental sensitivity and human error, improving calibration accuracy and robustness, thus possessing high precision and adaptability. It eliminates manual intervention, achieving rapid and efficient calibration and correction, with fully automated operation, suitable for batch or online calibration needs of single or multi-channel phase shifters. It effectively eliminates the nonlinearity, hysteresis, and coupling effects of the phase shifter, achieving nanometer-level phase shift control with high precision and stability. Furthermore, it is not limited to the use of Fizeau interferometers; dry methods can still be used for phase shift correction in other two-beam interferometric structures such as Thyman-Green, Michelson, or Mach-Zehnder. This method significantly improves the automation level and practicality of phase shifter calibration, providing more reliable performance assurance for high-precision optical detection systems.

[0057] The above describes a phase shifter calibration method. The present invention also provides a phase shifter calibration device, including an optical interferometry detection module and a control module; the control module includes a controller and a processor; the controller is connected to the phase shifter in the optical interferometry detection module. The controller is used to apply a preset voltage sequence to the phase shifter, and after receiving the slope ratio sent by the processor, to determine the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, and to apply the current voltage sequence as the new preset voltage sequence to the phase shifter. The optical interference detection module is used to acquire interference fringe patterns at each voltage in a preset voltage sequence; The processor is used to acquire interference fringe patterns at each voltage in a preset voltage sequence through an optical interference detection module; obtain the actual phase shift of the phase shifter based on the interference fringe patterns at each voltage, and determine the actual phase shift slope of the phase shifter based on the actual phase shift and voltage; if the actual phase shift slope meets the preset phase shift slope requirement, the calibration of the phase shifter is determined to be complete; if the actual phase shift slope does not meet the preset phase shift slope requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; and the slope ratio is transmitted to the controller.

[0058] The phase shifter calibration device provided in this embodiment has the same or corresponding technical features as the phase shifter calibration method described above. The embodiments of the phase shifter calibration method have been described in detail above, and the embodiments of the phase shifter calibration device will not be repeated here, and the effects are the same as above.

[0059] The phase shifter calibration method and calibration apparatus provided by the present invention have been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principle of the invention, and these improvements and modifications also fall within the protection scope of the present invention.

[0060] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A phase shifter calibration method, characterized in that, This is applied to a phase shifter calibration device, which includes an optical interferometry detection module and a control module; the control module includes a controller and a processor. The controller is connected to the phase shifter in the optical interferometry detection module; the method includes: The controller applies a preset voltage sequence to the phase shifter, and the optical interference detection module acquires the interference fringe pattern at each voltage in the preset voltage sequence. The actual phase shift of the phase shifter is obtained based on the interference fringe pattern at each voltage, and the actual phase shift slope of the phase shifter is determined based on the actual phase shift and the voltage. If the actual phase shift slope is detected to meet the preset phase shift slope requirement, then the calibration of the phase shifter is determined to be complete. If the actual phase shift slope is detected to not meet the preset phase shift slope requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; the slope ratio is transmitted to the controller so that the controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier coefficient and the preset voltage sequence, and applies the current voltage sequence as the new preset voltage sequence to the phase shifter.

2. The phase shifter calibration method according to claim 1, characterized in that, Before determining the actual phase shift slope of the phase shifter based on the actual phase shift and voltage of the phase shifter, the following is also included: Obtain the target phase shift; If the difference between the actual phase shift and the target phase shift is detected to be greater than the difference threshold, then proceed to the step of determining the actual phase shift slope of the phase shifter based on the actual phase shift and voltage of the phase shifter; Conversely, the process ends.

3. The phase shifter calibration method according to claim 1, characterized in that, In the case of a single lens driven by a phase shifter, the preset phase shift slope requirement is that the difference between the actual phase shift slope and the target phase shift slope is less than a first preset value; In the case where multiple phase shifters drive a single lens, the preset phase shift slope requirement includes a first preset requirement and / or a second preset requirement; The first preset requirement is that the difference between the actual phase shift slopes of any two phase shifters is less than the second preset value. The second preset requirement is that the difference between the total actual phase shift slope corresponding to all phase shifters and the target phase shift slope is less than the third preset value.

4. The phase shifter calibration method according to claim 3, characterized in that, The phase shifter calibration device includes multiple controllers, and each controller is connected to a phase shifter in a one-to-one correspondence. All controllers are connected to the processor. The preset phase shift slope requirement includes the first preset requirement and the second preset requirement; Determining the completion of phase shifter calibration includes: If the actual phase shift slope is detected to meet the first preset requirement, it is determined whether the actual phase shift slope meets the second preset requirement; If so, then the calibration of the phase shifter is complete.

5. The phase shifter calibration method according to claim 4, characterized in that, If, after detecting that the actual phase shift slope meets the first preset requirement, the actual phase shift slope does not meet the second preset requirement, then obtaining the ratio between the target phase shift slope and the actual phase shift slope to determine the slope ratio includes: The ratio between the target phase shift slope and the total actual phase shift slope corresponding to all phase shifters is obtained to determine the slope ratio. The controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, including: The product of the slope ratio and the preset total voltage multiplier coefficient is obtained to determine the new total voltage multiplier coefficient; The current voltage multiplier is determined based on the product of the new total voltage multiplier and the preset voltage multiplier. The current voltage sequence is determined based on the product of the current voltage multiplier and the preset voltage sequence.

6. The phase shifter calibration method according to claim 4, characterized in that, Also includes: If the actual phase shift slope is detected to not meet the first preset requirement, the step of obtaining the ratio between the target phase shift slope and the actual phase shift slope to determine the slope ratio includes: For each phase shifter, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; The controller determines the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, including: Obtain the product of the slope ratio and the preset voltage multiplier coefficient to determine the new preset voltage multiplier coefficient; The current voltage multiplier is determined by the product of the new preset voltage multiplier and the preset total voltage multiplier. The current voltage sequence is determined based on the product of the current voltage multiplier and the preset voltage sequence.

7. The phase shifter calibration method according to any one of claims 3 to 6, characterized in that, Also includes: Obtain the number of new preset voltage sequences; If the number of new preset voltage sequences detected is less than the threshold, the calibration of the phase shifter is considered complete.

8. The phase shifter calibration method according to claim 7, characterized in that, Before applying a new preset voltage sequence to the phase shifter, the controller also includes: Obtain the operating voltage range of the phase shifter; If all voltages in the new preset voltage sequence are detected to be within the operating voltage range, then proceed to the step of applying the new preset voltage sequence to the phase shifter; If a voltage outside the operating voltage range is detected in a new preset voltage sequence, a prompt message indicating that the voltage sequence is out of range is output.

9. The phase shifter calibration method according to claim 8, characterized in that, Before applying a preset voltage sequence to the phase shifter via the controller, the following is also included: Set the preset voltage multiplier coefficient, the operating voltage range, the threshold, and the target phase shift slope for the phase shifter; The preset voltage multiplier, the operating voltage range, the threshold, and the target phase shift slope are transmitted to the controller.

10. A phase shifter calibration device, characterized in that, It includes an optical interferometry detection module and a control module; the control module includes a controller and a processor; the controller is connected to the phase shifter in the optical interferometry detection module. The controller is configured to apply a preset voltage sequence to the phase shifter, and after receiving the slope ratio sent by the processor, determine the current voltage sequence based on the slope ratio, the preset voltage multiplier, and the preset voltage sequence, and apply the current voltage sequence as a new preset voltage sequence to the phase shifter. The optical interference detection module is used to acquire interference fringe patterns at each voltage in the preset voltage sequence; The processor is configured to acquire interference fringe patterns at each voltage in the preset voltage sequence via an optical interference detection module; obtain the actual phase shift of the phase shifter based on the interference fringe patterns at each voltage; and determine the actual phase shift slope of the phase shifter based on the actual phase shift and the voltage; if the actual phase shift slope is detected to meet the preset phase shift slope requirement, then the calibration of the phase shifter is determined to be complete. If the actual phase shift slope is detected to not meet the preset phase shift slope requirement, the ratio between the target phase shift slope and the actual phase shift slope is obtained to determine the slope ratio; the slope ratio is then transmitted to the controller.

Images