A single-sensor-based optical element conjugate adjustment method, device and medium

Abstract

This invention discloses a method, apparatus, and medium for conjugate adjustment of optical elements based on a single sensor. The adjustment method includes: setting two optical elements with arbitrarily shaped through-holes of identical shape; sequentially illuminating two light sources, respectively projecting light onto a first and a second light-transmitting surface, and using an image sensor to acquire images of the two optical elements facing either the first or second light-transmitting surface; fixing one of the two optical elements as a reference, adjusting the other optical element while maintaining the plane of the adjusted optical element parallel to the corresponding light-transmitting surface, until the intersection-over-jump ratio of the two optical element images is within a preset threshold range. This invention solves the problems of low accuracy and poor consistency in manual assembly and adjustment methods. Using one optical element as a reference, the spatial projection of the two optical elements is acquired in real time through an imaging system, and the position and orientation of the other optical element are adjusted accordingly to achieve strict conjugate alignment of the two optical elements.

Description

Technical Field

[0001] This invention belongs to the field of machine vision, and particularly relates to a method, device and medium for conjugate adjustment of optical elements based on a single sensor. Background Technology

[0002] In precision optical systems, it is often necessary to achieve a precise spatial conjugate configuration of two optical elements with through-hole structures (such as slits) relative to a beam splitter prism. This configuration is widely used in spectral imaging, confocal measurement, interferometry, and beam shaping. In a typical application, the first optical element is placed on one side of the first light-transmitting surface of the beam splitter prism, and the second optical element is placed on the other side, forming a conjugate relationship through the beam-splitting surface inside the prism. To ensure system imaging quality, energy efficiency, or signal contrast, the two optical elements need to be precisely aligned in the direction perpendicular to the optical axis. Their conjugate error typically needs to be controlled within the micrometer or even sub-micrometer range, especially when the through-hole size is small, which drastically increases the difficulty of assembly and adjustment.

[0003] Traditional assembly and adjustment processes often rely on a combination of manual visual observation and mechanical fine-tuning frames. Operators use a magnifying microscope or camera monitor to observe the projection or transmitted images of two through-holes on the prism's imaging surface. By repeatedly rotating and translating the fine-tuning frame manually, the images of the two through-holes are visually aligned to approximately coincide. Then, adhesive is applied for curing or locking to secure the alignment. Finally, system-level performance testing verifies the conjugation effect. However, this method has several inherent drawbacks: First, the human eye has limited resolution, making it difficult to accurately quantify minute offsets and angular deviations, and subjective judgment varies greatly, leading to uncontrollable assembly and adjustment accuracy. Second, when the through-hole shape is not limited to rectangular slits, it is difficult to standardize the manual alignment benchmark, making cross-matching judgment even more challenging. Third, during curing or locking, adhesive shrinkage, stress release, or mechanical return errors can easily introduce secondary offsets, rendering the original alignment invalid. Fourth, in mass production, the process suffers from poor consistency and repeatability, severely restricting product yield and production efficiency, and rework operations are complex and costly.

[0004] Therefore, achieving high-precision, repeatable, and quantifiable automatic alignment of dual optical elements relative to a beam splitter during assembly and adjustment has become a pressing technical challenge in the field of precision optical assembly and adjustment. This invention addresses these issues by providing a single-sensor-based method, apparatus, and medium for conjugate adjustment of optical elements, fundamentally improving the insufficient precision and poor consistency of traditional assembly and adjustment methods. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned problems in the prior art and provide a method, device and medium for conjugate adjustment of optical elements based on a single sensor, which fundamentally improves the problems of insufficient accuracy and poor consistency of traditional assembly and adjustment methods.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: A method for conjugate modulation of optical elements based on a single sensor, comprising: Two flat optical elements with arbitrary-shaped through holes of the same shape are set up and located at the conjugate positions of the first and second light-transmitting surfaces of the beam splitter, respectively. The planes of the two optical elements are adjusted to be parallel to the first and second light-transmitting surfaces, respectively. Two light sources are lit in sequence, so that the two light sources emit uniform beams and are directed toward the first and second light-transmitting surfaces of the beam splitter. The two beams cover and pass through the through holes of the first and second optical elements, respectively, and are injected from the first and second light-transmitting surfaces. The images of the two optical elements are collected by the image sensor facing the first or second light-transmitting surface. Fix one of the two optical elements as a reference, adjust the other optical element, and keep the plane of the adjusted optical element parallel to the corresponding light-transmitting surface until the intersection ratio of the images of the two optical elements is within a preset threshold range. The first light-transmitting surface and the second light-transmitting surface are adjacent to each other and are located on opposite sides of the beam-splitting surface of the beam-splitting prism, respectively; the photosensitive surface of the image sensor is parallel to the first light-transmitting surface or the second light-transmitting surface; the optical axis of the light source is consistent with the optical axis of the beam-splitting prism, and the uniform beam has consistent illuminance at any position on a plane perpendicular to the optical axis of the light source.

[0007] Furthermore, fixing either of the two optical elements as a reference component includes: using a pre-fabricated thickness of glass gasket to bond and fix it to both the reference component and the beam splitter prism.

[0008] Furthermore, before fixing the reference component, the process includes: moving the reference component vertically along the plane of the reference component until the width of the corresponding optical element image falls within a preset width range, and selecting a glass pad of corresponding thickness based on the distance between the reference component and the beam splitter.

[0009] Further, the adjustment to make the planes containing the two optical elements parallel to the first and second light-transmitting surfaces, respectively, includes: A telecentric lens is used to face the non-light-transmitting surface of the beam splitter to photograph the two optical elements, resulting in side view images of the two optical elements; Adjust the two optical elements separately until the intersection of the non-light-transmitting surface of the beam splitter and the first light-transmitting surface and the second light-transmitting surface is parallel to the length direction of the side view image corresponding to the first optical element and the second optical element, and the width of the two side view images is equal to the imaging width under the theoretical posture. The non-light-transmitting surface is perpendicular to both the first light-transmitting surface and the second light-transmitting surface.

[0010] Furthermore, adjusting another optical element includes: Move the current optical element along a direction perpendicular to the plane where the current optical element is located until the widths of the two optical element images are equal; Calculate the slope difference in the same feature direction in the images of two optical elements, and adjust the rotation angle of the current optical element according to the slope difference; Calculate the centroid offset between the two optical element images, and translate the current optical element along the plane where the current optical element is located based on the centroid offset; The mapping relationship between the centroid offset and the corresponding translation is known.

[0011] Furthermore, after adjusting another optical element, the process also includes: Measure the distance between the current optical element and the beam splitter, and select a gasket of the corresponding thickness to apply adhesive to the current optical element by deducting the reserved adhesive layer thickness; Adjust the current optical element during the dispensing and curing process to keep the cross-over ratio of the two optical element images within a preset threshold range.

[0012] Furthermore, the optical element is a slit.

[0013] The present invention also provides a method for conjugate adjustment of optical elements based on a single sensor, comprising: Two flat optical elements with arbitrarily shaped through holes of the same shape are set up and located at conjugate positions on both sides of the flat beam splitter. The planes of the two optical elements are adjusted so that they are perpendicular to each other and both form a 45-degree angle with the plane of the flat beam splitter. Two light sources are lit in sequence, so that the two light sources emit uniform beams and are directed toward both sides of the flat beam splitter. The two beams cover and pass through the through holes of the first optical element and the second optical element, respectively, and enter from both sides of the flat beam splitter. An image sensor is used to collect images of the two optical elements by facing the opposite side of one of the optical elements. Fix one of the two optical elements as a reference, adjust the other optical element, and at the same time keep the plane of the adjusted optical element at a 45-degree angle to the plane of the flat beam splitter until the image intersection ratio of the two optical elements is within the preset threshold range. The image sensor is parallel to the plane containing one of the optical elements; the optical axis of the light source is consistent with the optical axis of the flat beam splitter, and the uniform beam has consistent illuminance at any position on a plane perpendicular to the optical axis of the light source.

[0014] This invention also provides a single-sensor-based optical element conjugate adjustment device, which utilizes the above-described adjustment method to achieve adjustment. It is used to position two planar optical elements at conjugate positions on the first and second light-transmitting surfaces of a beam splitter, wherein the first and second light-transmitting surfaces are adjacent and located on opposite sides of the beam splitter surface. The adjustment device includes: Two light sources are respectively positioned on the side of the two optical elements away from the beam splitter, for emitting uniform light beams and directing them toward the first and second light-transmitting surfaces of the beam splitter. The two light beams respectively cover and pass through the through-holes of the first and second optical elements, and enter from the first and second light-transmitting surfaces. The optical axis of the light source is aligned with the optical axis of the beam splitter, and the uniform light beam has the same illuminance at any position on a plane perpendicular to the optical axis of the light source. An image sensor, positioned on either the first or second light-transmitting surface, is used to acquire images from two optical elements. The adjustment mechanism includes a translation adjustment module and a rotation adjustment module. The translation adjustment module is used to translate the optical element in the direction perpendicular to the plane where the optical element is located. The rotation adjustment module is used to rotate the optical element in the plane where the optical element is located, while keeping the plane where the optical element is located parallel to the corresponding light-transmitting surface, until the intersection ratio of the two optical element images is within a preset threshold range. Both optical elements have through holes of arbitrary shape and the through holes are identical. They are respectively set at the conjugate position of the first and second light-transmitting surfaces of the beam splitter, and the planes on which the two optical elements are located are parallel to the first and second light-transmitting surfaces, respectively.

[0015] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described adjustment method.

[0016] The beneficial effects of this invention are: (1) This invention fundamentally solves the problems of low precision and poor consistency in traditional manual assembly and adjustment methods. Taking one of the optical elements as a reference, the spatial projection of the two optical elements is obtained in real time through the imaging system, and the position and orientation of the other optical element are adjusted accordingly. Strict conjugate alignment of the two optical elements can be achieved at the sub-pixel level, which significantly improves the spectral resolution and signal-to-noise ratio of the coaxial spectral confocal system.

[0017] (2) The present invention only requires adjustment of six degrees of freedom of the current optical element. By fixing one of the optical elements in advance as a reference, only the six degrees of freedom of the other optical element need to be adjusted in the subsequent process, which simplifies the complexity of the adjustment model.

[0018] (3) The present invention only requires one image sensor for monitoring the spatial pose of the current optical element after it is parallel: After installing the second light-transmitting surface of the beam splitter so that the plane where the current optical element is located is parallel to the second light-transmitting surface, the image sensor can be installed on the side of the first light-transmitting surface or the side of the second light-transmitting surface. The spatial pose adjustment of the current optical element can be realized. Only one set of equipment is needed to monitor the displacement, rotation and optical axis movement of the plane where the current optical element is located, which has a higher degree of integration. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a flowchart of the adjustment method in this invention; Figure 2 This is a schematic diagram of the adjustment device in this invention.

[0020] In the figure: 1-beam splitter prism; 11-first light-transmitting surface; 12-second light-transmitting surface; 13-beam splitter surface; 2-first optical element; 3-second optical element; 4-first light source; 5-second light source; 6-image sensor. Detailed Implementation

[0021] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] For ease of understanding, let's take the dual-slit assembly and adjustment in a coaxial spectral confocal system as an example. Traditional slit bonding assembly and adjustment methods are no longer sufficient to meet the demands of mass production and high reliability. To further improve the reliability of slit adjustment, consider the following two methods: First, there is the bonding method based on mechanical limiting and shim control. The operator first fixes the beam splitter to the base, then inserts a metal or thin-film shim approximately 30μm thick between the slit and the beam splitter to control the adhesive layer gap. Optical adhesive is then applied to the side to fill the gap, and finally the shim is removed and cured. However, this method has drawbacks: the shim itself has manufacturing tolerances (±3-5μm) and is prone to deformation after repeated use, resulting in poor adhesive layer thickness consistency; changes in the air gap cannot be observed in real time during adjustment, making it difficult to compensate for beam splitter surface errors or slit substrate warping; the conjugate alignment between the two slits relies entirely on external references or operator visual inspection, with an accuracy typically only reaching ±5μm, which cannot meet submicron-level conjugate requirements.

[0023] Second, a visually assisted bonding method using a single-axis or three-axis displacement stage and a microscope is employed. The slit is mounted on a three-axis precision displacement stage, a beam splitter is fixed, and the intersection-to-exclusion ratio of the slit edge and the prism's marked line is observed under a microscope. The displacement stage is then adjusted gradually. The adhesive layer thickness is indirectly calculated using the stage's feed scale or a displacement sensor. After adhesive dispensing and curing, testing and verification are performed. However, this method has several drawbacks: the microscope's limited depth of field makes it difficult to clearly image and quantify the minute air gap (approximately 30 μm) between the prism and the slit; adhesive layer thickness control is an "open-loop" method, unable to be corrected in real-time after dispensing and before curing, making it prone to deviations from the target thickness due to adhesive shrinkage or surface tension; and when the two slits are assembled and adjusted independently, the lack of a fixed "reference slit" as a conjugate reference leads to accumulated relative positional errors between the two slits. Example 1

[0024] To solve similar problems mentioned above with optical components, such as Figure 1 As shown, this embodiment first provides a method for conjugate adjustment of optical elements based on a single sensor, including: Two flat optical elements with identical through-holes of arbitrary shape are arranged and positioned conjugate to the first and second light-transmitting surfaces of a beam-splitting prism. The planes of the two optical elements are adjusted so that they are parallel to the first and second light-transmitting surfaces, respectively. The first and second light-transmitting surfaces, as well as their opposite sides, are used for light transmission. The first and second light-transmitting surfaces are adjacent and located on opposite sides of the beam-splitting surface of the prism. Both optical elements have through-holes of arbitrary shape. The "conjugate position" is a predetermined position, typically close to an ideal conjugate position, used as the initial state. The specific position can be set according to actual needs without undue limitation. Positioning the two optical elements in the conjugate position and ensuring strict parallelism provides a stable geometric reference for the entire assembly and adjustment process, avoiding systematic errors caused by reference drift and improving the controllability of subsequent alignment. Optical conjugation requires that the two optical elements not only be conjugate in directions perpendicular to their respective light-transmitting surfaces, but their own planar directions must also be perpendicular to the optical axis, i.e., parallel to the light-transmitting surfaces. If the plane containing the optical element is not parallel to the light-transmitting surface, it is equivalent to the optical element being tilted relative to the ideal optical path. This will cause the light beam to be unable to pass through the optical element or the light beam that passes through the optical element to be distorted and have uneven energy distribution, thus destroying the conjugate imaging quality. By adjusting the parallelism of the two optical elements, the attitude foundation is laid for achieving high-precision image superposition. The beam splitter includes four light-transmitting surfaces around its perimeter and non-light-transmitting surfaces at both ends. Taking the double-slit assembly scenario in a coaxial spectral confocal system as an example, the two optical elements correspond to the two slits. The first light-transmitting surface corresponds to the first optical element. The light beam passes through the first optical element, the first light-transmitting surface, the beam-splitting surface of the beam splitter, and the dispersive lens to reach the surface of the object under test. After reflection, it passes through the dispersive lens, the beam-splitting surface of the beam splitter, and the second light-transmitting surface to reach the second optical element.

[0025] Two light sources are sequentially illuminated, each emitting a uniform beam that strikes the first and second light-transmitting surfaces of a beam splitter. The two beams respectively cover and pass through the apertures of the first and second optical elements, entering through the first and second light-transmitting surfaces. An image sensor captures images of the two optical elements from either the side facing the first or second light-transmitting surface. The photosensitive surface of the image sensor is parallel to either the first or second light-transmitting surface. The optical axis of the light source is aligned with the optical axis of the beam splitter, and the uniform beam exhibits consistent illuminance at any position on a plane perpendicular to the optical axis of the light source. This step utilizes the inherent optical characteristics of the beam splitter to achieve the "visualization" and "quantification" of the conjugate state of the two optical elements. When the first and second optical elements are illuminated by light sources, the light emitted from the first optical element enters the beam splitter through the first light-transmitting surface. After reaching the beam splitter, a portion of the light is transmitted to the side of the first light-transmitting surface and exits. The light emitted from the second optical element enters the beam splitter through the second light-transmitting surface and, after reflection, also exits from the same side, i.e., the side of the first light-transmitting surface (or both can exit from the second light-transmitting surface). Therefore, by placing an image sensor outside the exit surface, the images of the two optical elements can be observed separately, namely the image of the first optical element and the image of the second optical element. The intersection-union ratio (CIU) of the first and second optical element images in the same image coordinate system directly and accurately reflects the physical conjugate state of the two optical elements in the optical path inside the beam splitter. This step transforms the invisible and abstract "optical conjugate" relationship into an intuitive and quantifiable "image coincidence" problem. This achieves real-time precision detection, eliminates reliance on operator visual observation, and provides accurate feedback signals (image differences) for subsequent adjustments, serving as a technical prerequisite for the entire automated precision adjustment process.

[0026] One of the two optical elements is fixed as a reference, and the other optical element is adjusted while keeping the plane of the adjusted optical element parallel to the corresponding light-transmitting surface until the image intersection-to-union ratio of the two optical elements is within a preset threshold range. The first optical element is fixed as a reference on the first light-transmitting surface of the beam splitter. Fixing can be done using any method such as bonding, clamping, magnetic attraction, or vacuum adsorption as needed. After fixing the first optical element, only the second optical element needs to be adjusted, reducing the adjustment freedom from six degrees of freedom for two elements to six degrees of freedom for one element, greatly simplifying the complexity and optimization difficulty of the adjustment model, and improving the determinism and efficiency of the adjustment. In specific operation, a glass gasket of customized thickness is used as a positioning aid to bond the first optical element to the conjugate position of the first light-transmitting surface of the beam splitter. By controlling the thickness of the glass gasket, the initial distance between the first optical element and the surface of the beam splitter strictly conforms to the optical design dimensions; at the same time, a height gauge can be used to check the flatness of the first optical element to ensure that its parallelism deviation with the reference surface of the beam splitter is less than 10μm. The beam-splitting prism assembly with the first optical element already bonded is fixed to the air-floating platform where the six-axis controller is located to ensure positional stability during subsequent adjustments. Based on the first and second optical element images extracted from the acquired images, the second optical element is adjusted by a control system such as the six-axis controller, allowing for fine adjustments to its position and orientation at the micron or even sub-micron level. The ultimate goal of the adjustment is to ensure that the intersection-union ratio (IU) of the two optical element images is within a preset threshold range, meaning that the real-time images of the two optical elements completely overlap on the display screen. The "IU" refers to the ratio of the intersection to the union of the aperture images of the two optical elements, that is, the ratio of the area of ​​the overlapping portion of the aperture images of the two optical elements to the total area covered by the aperture images of the two optical elements. The closer the IU is to 1, the better the overlap effect. A specific preset threshold range can be set according to the actual situation. According to geometric optics and aberration theory, when the two optical elements are in ideal positions in the conjugate optical path of the beam-splitting prism, the images formed by them after passing through the prism are completely identical in space. Conversely, if two images are misaligned in the same image coordinate system, it directly indicates that the physical positions of the two optical elements deviate from the ideal conjugate state. Therefore, "image coincidence" is an accurate mapping of "physical conjugate" in image space. By continuously adjusting the second optical element and observing the image, a negative feedback loop is formed until the cross-union ratio is within a preset threshold range, thus achieving high-precision conjugate alignment.

[0027] Through the above steps, this invention achieves the following effects: First, only six degrees of freedom of the second optical element need to be adjusted: The first optical element is fixed beforehand as a reference component, and only six degrees of freedom of the second optical element need to be adjusted in subsequent processes, simplifying the complexity of the adjustment model. Second, only one image sensor is needed for spatial pose monitoring of the second optical element after it is paralleled: After installing the second optical element so that its plane is parallel to the second light-transmitting surface of the beam splitter, an image sensor can be installed on either the side of the first or second light-transmitting surface to achieve spatial pose adjustment of the second optical element. Only one set of equipment is needed to monitor the displacement, rotation, and optical axis movement of the plane containing the second optical element, resulting in higher integration.

[0028] In a specific embodiment of the present invention, fixing one of the two optical elements as a reference component includes: bonding and fixing a pre-thickened glass spacer to both the reference component and the beam splitter prism. After curing, the optical adhesive has an optimal thickness range (e.g., 30 μm); too thin or too thick a layer will affect strength and stability, and direct application of adhesive cannot precisely control the gap. The glass spacer provides a precise and rigid physical separation. The glass spacer has precise thickness tolerance and flatness, allowing for standardized control of the distance between the optical element and the prism, replacing the vague method of manual adhesive application for thickness control. The fixed thickness of the spacer enables precise pre-setting of the adhesive layer spacing, while ensuring the flatness of the assembly plane of the optical element. By precisely controlling the gap between the bottom surface of the first optical element and the light-transmitting surface of the prism using the spacer, the thickness of the subsequent adhesive layer is equal to the thickness of the spacer, achieving precise and quantitative control of the adhesive layer thickness. This avoids the spacing deviation and uneven adhesive layer thickness problems caused by manual bonding, improving the consistency and stability of the reference end assembly. Simultaneously, the spacer increases the bonding area and improves structural rigidity.

[0029] To ensure a reasonable spacing between the optical elements and the beam splitter, before fixing the reference component, the following steps are taken: moving the reference component perpendicular to its plane until the width of the corresponding optical element image falls within a preset width range, and selecting a glass spacer of appropriate thickness based on the spacing between the reference component and the beam splitter. The width of the two optical element images depends not only on the physical width of the optical elements themselves but also on their defocusing amount in the optical path. Only when the two optical elements are located near the optimal conjugate image plane will the image be sharpest, with the smallest width equal to the theoretical value. By finding the "minimum width" position, the optimal focal plane position can be precisely located.

[0030] To ensure the parallelism of the two optical elements, adjustments are made to make the planes containing the two optical elements parallel to the first and second light-transmitting surfaces, respectively. This includes: using a telecentric lens facing the non-light-transmitting surface of the beam splitter to photograph the two optical elements, obtaining side-view images of the two optical elements; adjusting the two optical elements until the intersection lines of the non-light-transmitting surface of the beam splitter with the first and second light-transmitting surfaces are parallel to the length direction of the corresponding side-view images of the first and second optical elements, respectively, and the width of the two side-view images is equal to the imaging width under the theoretical orientation; wherein the non-light-transmitting surface is simultaneously perpendicular to the first and second light-transmitting surfaces. The imaging width under the theoretical orientation is pre-calculated based on optical design parameters. The telecentric lens has the advantages of parallel light imaging and no perspective distortion, and can accurately capture the lateral attitude deviation of the optical elements; the lateral shooting angle can directly reflect the pitch and yaw angles of the optical elements, compensating for the deficiency of frontal imaging in identifying attitude tilt angles, and providing a basis for subsequent adjustments. This step accurately acquires the lateral attitude information of optical components without imaging distortion. It efficiently identifies minute tilt errors in optical components, providing precise image data for optical component plane parallelism calibration and improving attitude adjustment accuracy. When the planes containing the two optical components are completely parallel to the first and second light-transmitting surfaces of the beam splitter, the length direction of the side view images of the two optical components will be parallel to the edge of the beam splitter, and the imaging width of the two optical components will be consistent. If there is a tilt angle, the imaging will be tilted and the width will be widened. This can be used as a basis for accurate attitude calibration. This step decomposes the complex spatial parallelism adjustment into two intuitive image feature comparisons (parallel edges and equal width), making the adjustment process data-driven, enabling automated judgment and closed-loop control, and ensuring the accuracy and efficiency of parallelism adjustment.

[0031] As shown above, after adjusting the plane of the second optical element to be parallel to the second light-transmitting surface of the beam splitter, the pose of the second optical element needs to be adjusted along the optical axis and the plane of the second optical element. Specifically, adjusting the second optical element includes: moving the current optical element along a direction perpendicular to the plane of the current optical element until the widths of the two optical element images are equal; calculating the slope difference of the same feature direction in the two optical element images and adjusting the rotation angle of the current optical element according to the slope difference; calculating the centroid offset of the two optical element images and translating the current optical element along the plane of the current optical element according to the centroid offset; wherein, the mapping relationship between the centroid offset and the corresponding translation is known. The same feature direction is the straight line direction formed by connecting any two identical feature points in the two optical element images. Decomposing the process of adjusting the second optical element to achieve image overlap into two ordered steps of rotation and translation, the inconsistent image widths are essentially caused by the different defocus amounts of the two optical elements. By moving the second optical element along a direction perpendicular to the second light-transmitting surface (i.e., along the optical axis), the distance between the second optical element and the beam splitter can be changed, allowing its image width to match the fixed image width of the first optical element. This corresponds to the two achieving conjugation along the optical axis. Based on this consistent width (i.e., confocal), further displacement or rotation along the plane of the second optical element is needed to make the outlines of the first and second optical element images coincide, thus achieving complete spatial conjugation. This step first resolves the main problem (defocus) through a one-dimensional search, then addresses the coincidence problem in the two-dimensional plane. This avoids complex coupled searches in six-degree-of-freedom space, greatly simplifying the complexity of the control algorithm and improving the adjustment speed and success rate.

[0032] To further address the curing misalignment issue during dispensing, after adjusting the other optical element, the process includes: measuring the distance between the current optical element and the beam splitter; selecting a pad of the appropriate thickness for dispensing onto the current optical element by subtracting the reserved adhesive layer thickness; adjusting the current optical element during the dispensing curing process to maintain the image cross-junction ratio of the two optical elements within a preset threshold range. After achieving precise alignment, the remaining gap, corresponding to the reserved adhesive layer thickness, is observed through a side telecentric lens; dispensing is then performed only if the expected thickness is met. After bonding, the optical element pose may change slightly due to the adhesive layer, requiring further fine-tuning until the images re-align. This step resolves the contradiction between "precise alignment" and "adhesive layer thickness control." Through alignment, measurement, pad selection, and re-alignment, it ensures both the accuracy of the final conjugate state and precise control of the adhesive layer thickness within the design value, balancing optical performance and mechanical reliability. Secondary fine-tuning compensates for deformation errors, locking in a high-precision assembly state. During UV curing, the alignment status of the two optical elements is continuously observed. Once a slight offset is detected due to glue flow or curing shrinkage, it can be immediately compensated and corrected using a six-axis controller to ensure that the established high-precision conjugate relationship is not changed during the curing process.

[0033] As a specific application scenario of the present invention, the above-mentioned optical element is a slit, which effectively solves the assembly and adjustment problem of double slits in the coaxial spectral confocal system and improves the reliability and consistency of slit adjustment. Example 2

[0034] As another embodiment of the adjustment method of the present invention, the present invention also provides a conjugate adjustment method for optical elements based on a single sensor, comprising: Two flat optical elements with arbitrarily shaped through holes of the same shape are set up and located at conjugate positions on both sides of the flat beam splitter. The planes of the two optical elements are adjusted so that they are perpendicular to each other and both form a 45-degree angle with the plane of the flat beam splitter.

[0035] Two light sources are lit in sequence, so that the two light sources emit uniform beams and are directed toward both sides of the flat beam splitter. The two beams cover and pass through the through holes of the first optical element and the second optical element, respectively, and enter from both sides of the flat beam splitter. An image sensor is used to collect images of the two optical elements from the opposite side of one of the optical elements.

[0036] Fix one of the two optical elements as a reference, adjust the other optical element, and at the same time keep the plane of the adjusted optical element at a 45-degree angle to the plane of the flat beam splitter until the image intersection ratio of the two optical elements is within the preset threshold range.

[0037] The image sensor is parallel to the plane containing one of the optical elements; the optical axis of the light source is consistent with the optical axis of the flat beam splitter, and the uniform beam has consistent illuminance at any position on a plane perpendicular to the optical axis of the light source.

[0038] The difference between Example 2 and Example 1 is that the beam splitter prism is replaced with a flat beam splitter. Although it is still a beam splitter, because the beam splitter's own light-transmitting surface is missing for parallel calibration, a new alignment method is adopted: "adjusting so that the planes of the two optical elements are perpendicular to each other and both form a 45-degree angle with the plane of the flat beam splitter." From a pose perspective, the plane of the flat beam splitter is equivalent to the beam-splitting surface of the beam splitter prism in Example 1; they are essentially the same and will not be described further here. Example 3

[0039] like Figure 2 As shown, to achieve the above adjustment method, the present invention also provides a single-sensor-based optical element conjugate adjustment device, which uses the above adjustment method to achieve adjustment. This device is used to place two planar optical elements at conjugate positions on the first light-transmitting surface 11 and the second light-transmitting surface 12 of a beam splitter 1. The beam splitter 1 is a cubic structure formed by cementing two right-angled triangular prisms together. The first light-transmitting surface 11 and the second light-transmitting surface 12 are adjacent and located on opposite sides of the beam splitting surface 13 of the beam splitter 1. The adjustment device includes: Two light sources are respectively positioned on the side of the two optical elements away from the beam splitter 1, emitting uniform beams that are directed towards the first and second light-transmitting surfaces 11 and 12 of the beam splitter 1. The two beams respectively cover and pass through the through-holes of the first optical element 2 and the second optical element 3, entering through the first and second light-transmitting surfaces 11 and 12. Each optical element has an arbitrarily shaped, identical through-hole, positioned conjugate to the first and second light-transmitting surfaces 11 and 12 of the beam splitter 1, with the planes of the two optical elements parallel to the first and second light-transmitting surfaces 11 and 12, respectively. The optical axes of the light sources are aligned with the optical axis of the beam splitter 1, and the uniform beams exhibit consistent illuminance at any position on a plane perpendicular to the optical axis of the light sources. The two optical elements include a first optical element 2 and a second optical element 3. The first optical element 2 is fixed to the conjugate position of the first light-transmitting surface 11 of the beam splitter 1, such that the plane of the first optical element 2 is parallel to the first light-transmitting surface 11. The second optical element 3 is installed to the conjugate position of the second light-transmitting surface 12 of the beam splitter 1, and adjusted so that the plane of the second optical element 3 is parallel to the second light-transmitting surface 12 of the beam splitter 1. The two light sources include a first light source 4 and a second light source 5. The first light source 4 is located on the side of the first optical element 2 away from the beam splitter 1, and is used to emit a first light beam that passes through the first optical element 2 to form an image of the first optical element. The second light source 5 is located on the side of the second optical element 3 away from the beam splitter 1, and is used to emit a second light beam that passes through the second optical element 3 to form an image of the second optical element.

[0040] Image sensor 6 is located on the opposite side of the first light-transmitting surface 11 or the opposite side of the second light-transmitting surface 12, and is used to acquire images from the two optical elements.

[0041] The adjustment mechanism includes a translation adjustment module and a rotation adjustment module. The translation adjustment module is used to translate the optical element perpendicularly to the plane of the optical element being adjusted, and the rotation adjustment module is used to rotate the optical element along the plane of the optical element being adjusted, while keeping the plane of the optical element being adjusted parallel to the corresponding light-transmitting surface, until the intersection-to-jump ratio of the two optical element images is within a preset threshold range. The adjustment mechanism as a whole can be adjusted directly using a six-axis controller, or the translation adjustment module and the rotation adjustment module can be selected separately. For example, the translation adjustment module can be a guide rail type translation adjustment mechanism such as a lead screw drive, piezoelectric ceramic drive, or motor drive, and the rotation adjustment module can achieve the rotation by driving the rotation of the shaft to drive the corresponding connecting parts.

[0042] The specific operating details of this device can be found in the adjustment method described above, and will not be repeated here. Example 4

[0043] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described adjustment method.

[0044] In practical applications, a computer-readable storage medium can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0045] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0046] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0047] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0048] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for conjugate adjustment of optical elements based on a single sensor, characterized in that, include: Two flat optical elements with arbitrary-shaped through holes of the same shape are set up and located at the conjugate positions of the first and second light-transmitting surfaces of the beam splitter, respectively. The planes of the two optical elements are adjusted to be parallel to the first and second light-transmitting surfaces, respectively. Two light sources are lit in sequence, so that the two light sources emit uniform beams and are directed toward the first and second light-transmitting surfaces of the beam splitter. The two beams cover and pass through the through holes of the first and second optical elements, respectively, and are injected from the first and second light-transmitting surfaces. The images of the two optical elements are collected by the image sensor facing the first or second light-transmitting surface. Fix one of the two optical elements as a reference, adjust the other optical element, and keep the plane of the adjusted optical element parallel to the corresponding light-transmitting surface until the intersection ratio of the images of the two optical elements is within a preset threshold range. The first light-transmitting surface and the second light-transmitting surface are adjacent to each other and are located on opposite sides of the beam-splitting surface of the beam-splitting prism, respectively; the photosensitive surface of the image sensor is parallel to the first light-transmitting surface or the second light-transmitting surface; the optical axis of the light source is consistent with the optical axis of the beam-splitting prism, and the uniform beam has consistent illuminance at any position on a plane perpendicular to the optical axis of the light source.

2. The method for conjugate adjustment of optical elements based on a single sensor according to claim 1, characterized in that, Fixing either of the two optical elements as a reference component includes: using a pre-fabricated glass gasket to bond and fix it to both the reference component and the beam splitter prism.

3. The method for conjugate adjustment of optical elements based on a single sensor according to claim 1, characterized in that, Before fixing the reference component, the process includes: moving the reference component vertically along the plane of the reference component until the width of the corresponding optical element image falls within a preset width range, and selecting a glass pad of corresponding thickness based on the distance between the reference component and the beam splitter.

4. The method for conjugate adjustment of optical elements based on a single sensor according to claim 1, characterized in that, The adjustment to make the planes containing the two optical elements parallel to the first and second light-transmitting surfaces, respectively, includes: A telecentric lens is used to face the non-light-transmitting surface of the beam splitter to photograph the two optical elements, resulting in side view images of the two optical elements; Adjust the two optical elements separately until the intersection of the non-light-transmitting surface of the beam splitter and the first light-transmitting surface and the second light-transmitting surface is parallel to the length direction of the side view image corresponding to the first optical element and the second optical element, and the width of the two side view images is equal to the imaging width under the theoretical posture. The non-light-transmitting surface is perpendicular to both the first light-transmitting surface and the second light-transmitting surface.

5. The method for conjugate adjustment of optical elements based on a single sensor according to claim 1, characterized in that, Adjusting another optical element includes: Move the current optical element along a direction perpendicular to the plane where the current optical element is located until the widths of the two optical element images are equal; Calculate the slope difference in the same feature direction in the images of two optical elements, and adjust the rotation angle of the current optical element according to the slope difference; Calculate the centroid offset between the two optical element images, and translate the current optical element along the plane where the current optical element is located based on the centroid offset; The mapping relationship between the centroid offset and the corresponding translation is known.

6. The method for conjugate adjustment of optical elements based on a single sensor according to claim 1, characterized in that, After adjusting another optical element, the following is also included: Measure the distance between the current optical element and the beam splitter, and select a gasket of the corresponding thickness to apply adhesive to the current optical element by deducting the reserved adhesive layer thickness; Adjust the current optical element during the dispensing and curing process to keep the cross-over ratio of the two optical element images within a preset threshold range.

7. A method for conjugate adjustment of optical elements based on a single sensor according to any one of claims 1-6, characterized in that, The optical element is a slit.

8. A method for conjugate adjustment of optical elements based on a single sensor, characterized in that, include: Two flat optical elements with arbitrarily shaped through holes of the same shape are set up and located at conjugate positions on both sides of the flat beam splitter. The planes of the two optical elements are adjusted so that they are perpendicular to each other and both form a 45-degree angle with the plane of the flat beam splitter. Two light sources are lit in sequence, so that the two light sources emit uniform beams and are directed toward both sides of the flat beam splitter. The two beams cover and pass through the through holes of the first optical element and the second optical element, respectively, and enter from both sides of the flat beam splitter. An image sensor is used to collect images of the two optical elements by facing the opposite side of one of the optical elements. Fix one of the two optical elements as a reference, adjust the other optical element, and at the same time keep the plane of the adjusted optical element at a 45-degree angle to the plane of the flat beam splitter until the image intersection ratio of the two optical elements is within the preset threshold range. The image sensor is parallel to the plane containing one of the optical elements; the optical axis of the light source is consistent with the optical axis of the flat beam splitter, and the uniform beam has consistent illuminance at any position on a plane perpendicular to the optical axis of the light source.

9. A single-sensor-based optical element conjugate adjustment device, using the adjustment method described in any one of claims 1-7, for setting two planar optical elements at conjugate positions on the first and second light-transmitting surfaces of a beam splitter, wherein... The first light-transmitting surface and the second light-transmitting surface are adjacent and located on opposite sides of the beam-splitting surface of the beam-splitting prism, characterized in that the adjustment device includes: Two light sources are respectively positioned on the side of the two optical elements away from the beam splitter, for emitting uniform light beams and directing them toward the first and second light-transmitting surfaces of the beam splitter. The two light beams respectively cover and pass through the through-holes of the first and second optical elements, and enter from the first and second light-transmitting surfaces. The optical axis of the light source is aligned with the optical axis of the beam splitter, and the uniform light beam has the same illuminance at any position on a plane perpendicular to the optical axis of the light source. An image sensor, positioned on either the first or second light-transmitting surface, is used to acquire images from two optical elements. The adjustment mechanism includes a translation adjustment module and a rotation adjustment module. The translation adjustment module is used to translate the optical element in the direction perpendicular to the plane where the optical element is located. The rotation adjustment module is used to rotate the optical element in the plane where the optical element is located, while keeping the plane where the optical element is located parallel to the corresponding light-transmitting surface, until the intersection ratio of the two optical element images is within a preset threshold range. Both optical elements have through holes of arbitrary shape and the through holes are identical. They are respectively set at the conjugate position of the first and second light-transmitting surfaces of the beam splitter, and the planes on which the two optical elements are located are parallel to the first and second light-transmitting surfaces, respectively.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the adjustment method as described in any one of claims 1-8.

Images