An absolute wavefront measurement precision testing device and method
By using a test apparatus and method that receives spherical wavefronts and moves the sensor position, the problem of low absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors is solved, achieving high-precision and low-cost absolute wavefront measurement, applicable to Hartmann-Shack wavefront sensors of different wavelengths.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU INST OF BIOMEDICAL ENG & TECH CHINESE ACADEMY OF SCI
- Filing Date
- 2023-07-26
- Publication Date
- 2026-07-21
AI Technical Summary
The existing Hartmann-Shack wavefront sensors have low absolute wavefront measurement accuracy, rely on expensive large-diameter collimators and have high environmental requirements, resulting in poor versatility.
A test apparatus and method are adopted to receive a spherical wavefront and move the sensor position. The absolute wavefront measurement accuracy is calculated by the control device. The beam is adjusted by an electric displacement stage and fiber optic head to avoid beam divergence. Different wavelength light sources are combined to achieve measurements in different bands.
It eliminates the need for high-precision planar wavefront devices, simplifies the measurement process, reduces costs, improves measurement accuracy and versatility, is easy to operate, and is suitable for Hartmann-Shack wavefront sensors of different wavelengths.
Smart Images
Figure CN116972989B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wavefront measurement technology, and specifically to a testing device and method for absolute wavefront measurement accuracy. Background Technology
[0002] The Hartmann-Shack wavefront sensor mainly consists of a microlens array and a photodetector positioned on the focal plane of the microlens array. As a wavefront measurement instrument, it is widely used in adaptive optics, laser beam quality diagnostics, atmospheric turbulence measurement, human eye aberration measurement, and performance parameter measurement of optical components and systems. The measurement accuracy of the Hartmann-Shack wavefront sensor determines its application range. Absolute wavefront measurement accuracy is one of the important parameters characterizing sensor performance; therefore, accurately measuring the absolute wavefront measurement accuracy of the Hartmann-Shack wavefront sensor is of great significance.
[0003] Currently, plane wavefronts are commonly used, and the measurements from Hartmann-Shack wavefront sensors are taken as the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors. This method is limited by the accuracy of plane wavefronts. High-precision plane wavefronts require large-diameter, long-focal-length collimators, which are expensive, result in large systems, and have stringent environmental requirements. Furthermore, collimators typically need to be customized according to wavelength; different collimators need to be developed for Hartmann-Shack wavefront sensors of different wavelengths, leading to poor versatility. Summary of the Invention
[0004] Therefore, the technical problem to be solved by the present invention is to solve the problems of low absolute wavefront measurement accuracy and high cost of measurement device using planar wavefront measurement sensor, thereby providing a test device and method for absolute wavefront measurement accuracy.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] In a first aspect, the present invention provides a testing device for absolute wavefront measurement accuracy, comprising: a sensor and a control device, wherein the sensor has a receiving end that receives a spherical wavefront and an output end that is connected to the control device, and is used to receive spherical wavefronts at multiple positions and send its own parameters and multiple position information to the control device; the control device calculates the absolute wavefront measurement accuracy of the sensor based on its own parameters and multiple position information sent by the sensor.
[0007] This invention provides a testing device for absolute wavefront measurement accuracy. The sensor receives a spherical wavefront, and the distance between the light source and the sensor's receiving end is changed by moving the sensor's position, thereby altering the spherical wavefront. This invention can directly measure the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without relying on a planar wavefront. Furthermore, by changing the light source to different wavelengths, the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors in different wavebands can be measured. The testing device has a simple structure, accurately measures the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without depending on the accuracy of the testing equipment or the measurement environment, and is easy to operate with rich functionality.
[0008] In one alternative embodiment, the testing apparatus for absolute wavefront measurement accuracy further includes: an electric displacement stage, the control end of which is connected to the control end of the control device, which carries the sensor and drives the sensor to translate based on the movement signal sent by the control device.
[0009] The test device for absolute wavefront measurement accuracy provided by this invention has a control device that can precisely control the distance the electric shift stage moves with the sensor each time, and directly read the position of the electric shift stage, thereby reducing measurement errors, saving measurement time, and improving measurement accuracy.
[0010] In one optional embodiment, the testing device for absolute wavefront measurement accuracy further includes: an optical fiber and an optical fiber head, wherein the light source is coupled through the optical fiber and then outputs a spherical wavefront through the optical fiber head.
[0011] The test device for absolute wavefront measurement accuracy provided by this invention can concentrate the output of the light source after optical fiber coupling into a spherical wavefront, avoiding beam divergence that causes inaccurate information acquisition by the sensor and improving measurement accuracy.
[0012] In one alternative embodiment, the testing apparatus for absolute wavefront measurement accuracy further includes a support fixedly connected to an optical fiber head, which is used to adjust the height of the optical fiber head so that the center of the spherical wavefront is at the same height as the sensor receiving end.
[0013] The absolute wavefront measurement accuracy testing device provided by this invention can align the fiber optic head with the receiving end of the sensor by adjusting the height of the support, so that the sensor receives all the light source, avoids beam divergence that causes inaccurate sensor data acquisition, and improves measurement accuracy.
[0014] In one alternative implementation, the sensor's intrinsic parameters include the aperture of the sensor receiver.
[0015] In a second aspect, the present invention provides a method for testing absolute wavefront measurement accuracy, applied to the testing device for absolute wavefront measurement accuracy provided in the first aspect. The method includes: controlling the sensor to be at the same height as the center of the spherical wavefront; moving the sensor to different positions according to a preset trajectory and a preset step size, and recording the wavefront aberration measurement value at each position; calculating the residual wavefront aberration at each position based on the wavefront aberration measurement value at each position; and calculating the absolute wavefront measurement accuracy based on the residual wavefront aberration at each position.
[0016] The method for testing the absolute wavefront measurement accuracy provided by this invention changes the distance between the light source and the sensor receiver by moving the sensor's position, thereby altering the spherical wavefront. This invention can directly measure the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without relying on a planar wavefront. Furthermore, by changing the light source to different wavelengths, the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors at different wavebands can be measured. The testing method is simple, accurately measuring the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without depending on the accuracy of the testing equipment or the measurement environment. It is easy to operate and offers rich functionality.
[0017] In one optional implementation, the process of moving the sensor to different positions according to a preset trajectory and a preset step size, and recording the wavefront aberration measurement value at each position, includes: moving the sensor to different positions, and continuously collecting a preset number of initial wavefront aberration measurements at each fixed position; and taking the average value of the preset number of initial wavefront aberration measurements at each fixed position as the wavefront aberration measurement value.
[0018] The method for testing the absolute wavefront measurement accuracy provided by this invention reduces errors by acquiring initial measurement values multiple times at one location, and avoids data deviations caused by device malfunctions affecting the test results of absolute wavefront measurement accuracy.
[0019] In one optional implementation, the process of calculating the residual wavefront aberration at each location based on the wavefront aberration measurement at each location includes: calculating the theoretical wavefront aberration value at each location; and taking the difference between the wavefront aberration measurement value at each location and its corresponding theoretical wavefront aberration value as the residual wavefront aberration at that location.
[0020] In one alternative implementation, the formula for calculating the absolute wavefront measurement accuracy (RMS) is as follows:
[0021]
[0022] Among them, R i Let be the residual wavefront aberration at position i; n is the number of moves. Attached Figure Description
[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a composition diagram of a specific example of a testing apparatus for absolute wavefront measurement accuracy according to an embodiment of the present invention;
[0025] Figure 2 This is a composition diagram of another specific example of a testing apparatus for absolute wavefront measurement accuracy according to an embodiment of the present invention;
[0026] Figure 3 This is a schematic diagram of the testing principle for absolute wavefront measurement accuracy according to an embodiment of the present invention;
[0027] Figure 4 This is a flowchart illustrating a method for testing the absolute wavefront measurement accuracy according to an embodiment of the present invention.
[0028] Figure 5 This is another schematic flowchart of a method for testing the absolute wavefront measurement accuracy according to an embodiment of the present invention;
[0029] Figure 6 This is another schematic flowchart of a test method for the absolute wavefront measurement accuracy according to an embodiment of the present invention. Detailed Implementation
[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0033] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0034] This embodiment provides a testing device for absolute wavefront measurement accuracy, such as... Figure 1 As shown, it includes: a sensor 1 and a control device 2. The sensor 1 receives spherical wavefronts at its receiving end and its output end is connected to the control device 2. It is used to receive spherical wavefronts at multiple preset positions and send its own parameters and multiple position information to the control device 2. The control device 2 calculates the absolute wavefront measurement accuracy of the sensor 1 based on its own parameters and multiple position information sent by the sensor 1.
[0035] For example, such as Figure 1 As shown, in this embodiment, sensor 1 is a Hartmann-Shack wavefront sensor. By moving the sensor along the direction of spherical wave propagation, the spherical wavefront at different preset positions is collected multiple times, and the absolute wavefront measurement accuracy is calculated by the control device 2.
[0036] The absolute wavefront measurement accuracy testing device provided in this embodiment uses a sensor to receive a spherical wavefront. By moving the sensor's position, the distance between the light source and the sensor's receiving end is changed, thereby altering the spherical wavefront. This embodiment can directly measure the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without relying on planar wavefronts. Furthermore, by changing the light source to different wavelengths, the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors in different wavebands can be measured. The testing device has a simple structure, accurately measures the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without relying on the accuracy of the testing equipment or the measurement environment, and is easy to operate with rich functionality.
[0037] In some alternative implementations, such as Figure 2 As shown, the test device for absolute wavefront measurement accuracy also includes: an electric displacement stage 3, whose control end is connected to the control end of the control device 2, which is used to carry the sensor 1, and drives the sensor 1 to translate based on the movement signal sent by the control device 2.
[0038] Specifically, such as Figure 2As shown, sensor 1 is placed on electric displacement stage 3. Electric displacement stage 3 moves according to the movement signal sent by control device 2. The movement distance and movement trajectory are preset in control device 2. Together with the movement signal, control electric displacement stage 3 to drive sensor 1 to move according to the movement distance and preset trajectory.
[0039] In some alternative implementations, such as Figure 2 As shown, the test device for absolute wavefront measurement accuracy also includes: optical fiber 4, optical fiber head 5, and bracket 6. The light source is coupled through optical fiber 4 and then outputs a spherical wavefront through optical fiber head 5. The bracket 6 is fixedly connected to optical fiber head 5 and is used to adjust the height of optical fiber head 5.
[0040] Specifically, such as Figure 2 As shown, the fiber optic head 5 concentrates the light source coupled through the fiber optic 4 into a spherical wavefront. The height of the fiber optic head 5 is adjusted by the bracket 6 so that the center of the spherical wavefront is at the same height as the sensor receiving end, thus avoiding beam divergence and causing inaccurate information acquisition by the sensor 1, and improving measurement accuracy.
[0041] It should be noted that other devices, such as lenses, can be used to convert the light source into a spherical wavefront, and this is not a limitation.
[0042] In some alternative implementations, such as Figure 3 As shown, the parameters of sensor 1 include: the aperture 2r of the sensor receiver.
[0043] Specifically, based on the aperture 2r of the sensor receiver and the distance from the fiber optic connector 5 to the sensor receiver, the theoretical RMS value of the spherical wavefront aberration of the sensor at different positions can be calculated. i The formula is as follows:
[0044]
[0045] Among them, L i The distance between sensor 1 and fiber optic head 5 at different positions.
[0046] This embodiment provides a method for testing the absolute wavefront measurement accuracy, applicable to the testing apparatus for absolute wavefront measurement accuracy provided in the above embodiments and any of their optional implementations, such as... Figure 4 As shown, the steps include:
[0047] Step S1: Control the sensor to be at the same height as the center of the spherical wavefront.
[0048] Specifically, refer to Figure 2Turn on the light source, adjust the bracket 6 so that the center of the fiber optic head 5 is at the same height as the center of the sensor 1, adjust the sensor 1 to the initial position, turn on the sensor 1 and record the current distance between the sensor 1 and the fiber optic head 5 as L1, control device 2 controls the sensor 1 to measure the spherical wavefront at the current position, and record the wavefront aberration measurement value W1 at the first position.
[0049] Step S2: Move the sensor to different positions according to the preset trajectory and preset step size, and record the wavefront aberration measurement value at each position.
[0050] Specifically, refer to Figure 2 The control device 2 controls the electric displacement stage 3 to move towards the fiber optic head 5 according to the preset step size ΔL; after the first movement, the distance between the sensor 1 and the fiber optic head 5 is recorded as L2; after the second movement, the distance between the sensor 1 and the fiber optic head 5 is recorded as L3; the control device 2 controls the sensor 1 to measure the spherical wavefront at two positions respectively, and records the wavefront aberration measurement values W2 and W3 at the second and third positions respectively.
[0051] Step S3: Calculate the residual wavefront aberration at each location based on the wavefront aberration measurements at each location.
[0052] Specifically, refer to Figure 2 The control device 2 obtains the residual wavefront aberrations R1 to R3 at the three positions based on the wavefront aberration measurement values W1 to W3 at the three positions respectively.
[0053] Step S4: Calculate the absolute wavefront measurement accuracy based on the residual wavefront aberration at each location.
[0054] Specifically, according to the formula for calculating the absolute wavefront measurement accuracy (RMS):
[0055]
[0056] Among them, R i Let i be the residual wavefront aberration at position i; n is the number of moves. When n is 3, and the residual wavefront aberrations R1 to R3 at the three positions are substituted, the absolute wavefront measurement accuracy RMS of sensor 1 can be calculated according to formula (2).
[0057] The method for testing the absolute wavefront measurement accuracy provided in this embodiment changes the distance between the light source and the sensor receiver by moving the sensor's position, thereby altering the spherical wavefront. This device can directly measure the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without relying on a planar wavefront. Furthermore, by changing the light source to different wavelengths, the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors at different wavelengths can be measured. The testing method is simple, accurately measuring the absolute wavefront measurement accuracy of Hartmann-Shack wavefront sensors without depending on the accuracy of the testing equipment or the measurement environment. It is easy to operate and offers rich functionality.
[0058] In some alternative implementations, such as Figure 5 As shown, the process of moving the sensor to different positions according to a preset trajectory and preset step size, and recording the wavefront aberration measurement value at each position, includes the following steps:
[0059] Step S21: Move the sensor to different positions, and at each fixed position, continuously collect a preset number of initial wavefront aberration measurements.
[0060] Step S22: Take the average value of the preset number of initial wavefront aberration measurements at each fixed position as the wavefront aberration measurement value.
[0061] For example, refer to Figure 2 Once sensor 1 is fixed in one position, it continuously collects 10 measurement values and calculates the average value as the wavefront aberration measurement value at the current position.
[0062] In some alternative implementations, such as Figure 6 As shown, the process of calculating the residual wavefront aberration at each location based on the wavefront aberration measurements at each location includes the following steps:
[0063] Step S31: Calculate the theoretical value of wavefront aberration for each location.
[0064] Step S32: Take the difference between the measured wavefront aberration value at each location and the corresponding theoretical wavefront aberration value as the residual wavefront aberration at that location.
[0065] Specifically, the theoretical RMS value of the spherical wavefront aberration of the sensor at different positions is calculated according to the above formula (1). i The wavefront aberration measurement W at this location i With RMS i The difference is taken as the residual wavefront aberration R at that location. i .
[0066] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A method for testing the absolute wavefront measurement accuracy, characterized in that, A testing apparatus for absolute wavefront measurement accuracy includes a sensor and a control device. The sensor receives a spherical wavefront at its receiving end and its output end is connected to the control device. The sensor receives spherical wavefronts at multiple locations and sends its own parameters and multiple location information to the control device. The control device calculates the absolute wavefront measurement accuracy of the sensor based on its own parameters and the multiple location information sent by the sensor. The method includes: The control sensor is aligned with the center of the spherical wavefront; The sensor is moved to different positions according to the preset trajectory and preset step size, and the wavefront aberration measurement value at each position is recorded. Calculate the residual wavefront aberration at each location based on the wavefront aberration measurements at each location; The absolute wavefront measurement accuracy is calculated based on the residual wavefront aberration at each location. The process of moving the sensor to different positions according to a preset trajectory and a preset step size, and recording the wavefront aberration measurement value at each position, includes: The sensor is moved to different locations, and at each fixed location, a preset number of initial wavefront aberration measurements are continuously collected. The average value of a preset number of initial wavefront aberration measurements at each fixed position is taken as the wavefront aberration measurement value. The process of calculating the residual wavefront aberration at each location based on the wavefront aberration measurements at each location includes: Calculate the theoretical value of wavefront aberration at each location; The difference between the measured wavefront aberration value at each location and its corresponding theoretical wavefront aberration value is taken as the residual wavefront aberration at that location. The formula for calculating the absolute wavefront measurement accuracy (RMS) is as follows: Among them, R i Let be the residual wavefront aberration at position i; n is the number of moves.
2. The method for testing the absolute wavefront measurement accuracy according to claim 1, characterized in that, The testing apparatus for absolute wavefront measurement accuracy also includes: An electric displacement stage, whose control end is connected to the control end of the control device, is used to carry the sensor and drives the sensor to translate based on the movement signal sent by the control device.
3. The method for testing the absolute wavefront measurement accuracy according to claim 1, characterized in that, The testing apparatus for absolute wavefront measurement accuracy also includes: optical fiber and fiber optic connector, among which... After being coupled through the optical fiber, the light source outputs a spherical wavefront through the fiber optic connector.
4. The method for testing the absolute wavefront measurement accuracy according to claim 3, characterized in that, The testing apparatus for absolute wavefront measurement accuracy also includes: A bracket, which is fixedly connected to the fiber optic head, is used to adjust the height of the fiber optic head so that the center of the spherical wavefront is at the same height as the sensor receiving end.
5. The method for testing the absolute wavefront measurement accuracy according to claim 1, characterized in that, The sensor's own parameters include: the aperture of the sensor receiver.