Chip automated light coupling system and method for 3lcos projection system

Abstract

An automated optical coupling system and method for a 3LCoS projection system are disclosed. The automated optical coupling system comprises: a white reference plate serving as a projection receiving surface; three six-degree-of-freedom micro-motion platforms, each supporting a red, green, and blue LCoS chip at its end; and a projection optics assembly fixed in front of the white reference plate, used to receive light from at least the three color channels reflected by the red, green, and blue LCoS chips. This system and method utilizes the LCoS chips to actively project a feature point array, calculates the relative six-degree-of-freedom pose between the chips by analyzing the distribution characteristics of the feature point array, and allows the reference plate to be within a working distance range of a non-precise focal plane, ultimately achieving rapid coupling of the three chips with high coupling accuracy.

Description

Technical Field

[0001] This invention relates to the field of optical projection technology, specifically to an automated optical coupling system and method for 3LCoS projection systems. Background Technology

[0002] In a 3LCoS projection system, three LCoS chips—red, green, and blue—modulate the three primary colors of light, requiring precise optical registration of the chips in space using an X-Cube combining prism. The precision of the chip coupling directly determines the final image quality of the projection system.

[0003] Currently, traditional LCoS chip coupling methods mainly have the following shortcomings: 1. Incomplete attitude detection: Existing technologies mostly only detect the translation deviation of the chip, and lack a direct detection method based on the imaging optical path for the tilt of the panel itself, resulting in overlap error or defocus at the edge of the image.

[0004] 2. Reliance on external calibration equipment: Some solutions require the use of external equipment such as laser interferometers and theodolites for absolute pose measurement, which makes the system complex, costly and difficult to deploy in batches on the production line.

[0005] 3. Poor environmental adaptability: Some testing solutions require the reference plane to be located on the precise focal plane of the lens, which makes the debugging environment harsh and unsuitable for rapid coupling on the production line. Summary of the Invention

[0006] The purpose of this invention is to propose an automated optical coupling system and method for chips in a 3LCoS projection system. The system utilizes an LCoS chip to actively project a feature point array, analyzes the distribution characteristics of the feature point array to calculate the relative six degrees of freedom pose between the chips, and allows the reference board to be located within the working distance range of a non-precise focal plane, ultimately achieving rapid coupling of the three chips with high coupling accuracy.

[0007] The technical solution adopted in this invention is: a chip-automated optical coupling system for a 3LCoS projection system, comprising: A white reference board is used as the projection receiving surface; Three six-degree-of-freedom micro-motion platforms, each with a red LCoS chip, a green LCoS chip, and a blue LCoS chip at its end; A projection optical component is fixed in front of the white reference plate and is used to receive light from the three color channels reflected by the red LCoS chip, the green LCoS chip and the blue LCoS chip, and to project the resulting feature point array image corresponding to the red channel, the green channel and the blue channel onto the projection receiving surface. An observation camera, mounted on the same side as the projection optics, is used to acquire an image of the feature point array projected onto the white reference plate; A central processing unit is electrically connected to a six-degree-of-freedom micro-motion platform, a red LCoS chip, a green LCoS chip, a blue LCoS chip, and an observation camera, respectively. The central processing unit is configured as follows: The red LCoS chip, green LCoS chip, and blue LCoS chip are controlled to light up sequentially in any order, and they are controlled to display a preset feature point array image. The system receives and processes feature point array images projected by each color channel from the observation camera. One color channel is taken as the reference channel, and the other two color channels are taken as non-reference channels. The deviation of the reference channel is calculated, and the six-degree-of-freedom relative deviation of the two non-reference channels relative to the reference channel is calculated based on the pose of the reference channel. The calculated parameters of the six-degree-of-freedom relative deviation are converted into driving commands for the six-degree-of-freedom micro-motion platform, and the two non-reference channels are adjusted in a closed loop so that their feature point array images coincide with the reference channel across the entire frame. The red, green, and blue LCoS chips are controlled to light up simultaneously, and the superimposed images of the three colors are collected for overlap verification. After the verification is passed, the three six-degree-of-freedom micro-motion platforms are fixed.

[0008] As a preferred embodiment, the projection optical components include a projection lens, a polarizing beam splitter, and an X-Cube beam combiner. The polarizing beam splitter is positioned between the exit surface of the X-Cube beam combiner and the projection lens. Incident light emitted from a white light source is guided by the polarizing beam splitter to the X-Cube beam combiner, where it is split into three monochromatic beams of red, green, and blue light. These beams then illuminate the red, green, and blue LCoS chips, respectively. The light carrying image information reflected from the three chips returns to the center of the X-Cube beam combiner and converges. The converged full-color image beam then passes through the polarizing beam splitter and enters the projection lens.

[0009] As a preferred embodiment, the six-degree-of-freedom micro-motion platform includes a micro-motion platform, a suction cup, and a mounting base; the red LCoS chip, the green LCoS chip, and the blue LCoS chip are respectively fixed on their respective mounting bases, and each mounting base is adsorbed onto the corresponding micro-motion platform by the suction cup.

[0010] As a preferred embodiment, the observation camera is fixed in front of the white reference plate, and its optical axis forms a certain angle with the projection optical path. During system assembly, the conversion relationship between the pixel array direction and the absolute horizontal / vertical direction of the system is established by calibration of the observation camera.

[0011] As a preferred embodiment, the central processing unit is further configured to: when using the current pose of one of the color channels as a reference, only perform translation and in-plane rotation adjustments on the six-degree-of-freedom pose corresponding to the reference, and align the six-degree-of-freedom poses of the other two color channels to the color channels corresponding to the reference.

[0012] A chip-based automated optical coupling method for 3LCoS projection systems includes the following steps: Step S1: Fix the red LCoS chip, green LCoS chip and blue LCoS chip to their respective six-degree-of-freedom micro-motion platforms, and place the white reference plate in front of the projection optical assembly as the projection receiving surface. Step S2: Control the six-degree-of-freedom micro-motion platform to move the red LCoS chip, green LCoS chip and blue LCoS chip to the preset initial spatial position in sequence; Step S3: In any order, the red LCoS chip, green LCoS chip and blue LCoS chip are lit up in a time-division manner, and they are controlled to display the feature point array image of the corresponding color channel. The feature point array image covers the effective display area of ​​the chip. Step S4: Acquire feature point array images of each color channel projected onto a white reference plate using an observation camera; Step S5: Process the three feature point array images acquired respectively. Take one color channel as the reference channel and the other two color channels as non-reference channels. Calculate the deviation of the reference channel and calculate the six-degree-of-freedom relative deviation of the two non-reference channels relative to the reference channel based on the pose of the reference channel. Step S6: Convert the calculated parameters of the six-degree-of-freedom relative deviation into driving commands for the six-degree-of-freedom micro-motion platform, and adjust the two non-reference channels in a closed loop so that their feature point array image coincides with the reference channel across the entire frame. Step S7: Control the red LCoS chip, green LCoS chip and blue LCoS chip to light up simultaneously, collect the three-color superimposed image for overlap verification, and fix the three six-degree-of-freedom micro-motion platforms after the verification is passed.

[0013] As a preferred embodiment, step S5 involves calculating the deviation of the reference channel and using the pose of the reference channel as a reference, including: The difference between the centroid of the array of the reference channel and the center of the camera image is calculated to characterize the translation deviation; the angle between the fitted line of the first row of feature points of the reference channel array and the horizontal axis of the image is calculated to characterize the in-plane rotation deviation; the chip corresponding to the reference channel is translated and rotated in-plane according to the difference and the angle until the feature point array image projected by the reference channel is within the field of view of the camera.

[0014] As a preferred embodiment, step S5, calculating the six-degree-of-freedom relative deviations of the two non-reference channels relative to the reference channel, includes: Calculate the difference between the array centroids of the two non-reference channels and the array centroid of the reference channel, as the relative translation deviation; Calculate the difference between the array principal axis direction of the two non-reference channels and the array principal axis direction of the reference channel, and use it as the in-plane rotational deviation. The difference between the rate of change of the spacing between the two non-reference channels and the rate of change of the array spacing between the reference channel is calculated and converted into the tilt angle deviation of the two non-reference channels relative to the reference channel through calibration mapping.

[0015] As a preferred embodiment, in step S6, the closed-loop adjustment of the two non-reference channels includes: first, adjusting the reference channel by translation and in-plane rotation to center its feature array and make its principal axis direction parallel to the horizontal axis of the observation camera's coordinate system; then, using the reference channel as a reference, adjusting the six-degree-of-freedom pose of the two non-reference channels in sequence; repeating steps S3 to S5 until the relative deviations between the reference channel and the two non-reference channels meet the system's preset accuracy requirements.

[0016] As a preferred embodiment, in step S7, the overlap verification specifically includes: extracting the coordinates of the three-color feature points, calculating the deviation distance between the feature points of each color channel, taking the maximum value as the three-color overlap deviation, and determining that the coupling is complete when the maximum value is less than a preset threshold.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Achieve fully automated six-degree-of-freedom detection: By analyzing the rate of change of row spacing and column spacing of the feature point array, the tilt angle deviation is quantitatively calculated. Combined with the centroid translation and spindle rotation deviation, six-degree-of-freedom relative pose detection is achieved for the first time in 3LCoS coupling, fully compensating for chip space deviation.

[0018] 2. The system adopts a relative alignment strategy and is self-contained: with the current pose of the red channel as the reference, the green and blue channels are directly aligned to the red channel. No external calibration equipment (such as a laser interferometer) is required. Only one camera is needed to complete the process, which reduces system cost and calibration complexity and is suitable for mass deployment on production lines.

[0019] 3. Full-field array registration to ensure edge overlap: The N×M array feature pattern covering the entire frame of the projection chip is used to achieve full-area registration from the center to the edge by analyzing the distribution pattern of feature points across the entire field, effectively solving the problem of large edge overlap error in traditional solutions.

[0020] 4. Allows the reference board to be out of focus, reducing environmental requirements: The white reference board does not need to be strictly located on the precise focal plane of the projection lens, allowing for a certain amount of defocus, which greatly reduces the stringent requirements of the debugging environment and improves the convenience and efficiency of production line operation.

[0021] 5. Combination of closed-loop coupling and quantitative verification: The closed-loop feedback of "detection-adjustment-re-detection" is adopted. Finally, quantitative verification is carried out by extracting the coordinates of the three-color feature points and calculating the maximum deviation distance, so as to ensure that the coupling accuracy is quantifiable and reproducible and avoid the error of human subjective judgment. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the chip automated optical coupling system in this invention; Figure 2 This is a flowchart of the automated optical coupling method for chips in this invention.

[0024] Reference numerals in the attached diagram: 1. White reference plate; 2. Projection lens; 3. Polarizing beam splitter; 4. X-Cube beam combiner; 5. Red LCoS chip; 6. Green LCoS chip; 7. Blue LCoS chip; 8. White light source; 9. Incident light; 10. Observation camera; 11. Micro-motion platform one; 12. Suction cup one; 13. Micro-motion platform two; 14. Suction cup two; 15. Micro-motion platform three; 16. Suction cup three; 17. Central processing unit. Detailed Implementation

[0025] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0026] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising," "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0027] To more clearly describe the chip-based automated optical coupling system and method used in the 3LCoS projection system, see the attached diagram. Figure 1-2 This embodiment is described as follows: like Figure 1 As shown, the present invention discloses a chip-automated optical coupling system for a 3LCoS projection system, comprising a white reference board 1, three six-degree-of-freedom micro-motion platforms, a projection optical component, and an observation camera 10.

[0028] A white reference plate 1 is used as the projection receiving surface; the white reference plate does not need to be strictly located at the optimal focal plane, and a certain amount of defocus is allowed.

[0029] Each six-degree-of-freedom micro-motion platform includes a micro-motion platform (micro-motion platform 11, micro-motion platform 2 13, micro-motion platform 3 15), a suction cup (suction cup 1 12, suction cup 2 14, suction cup 3 16), and a mounting base; the red LCoS5, green LCoS6, and blue LCoS7 are fixed on their respective mounting bases, and each mounting base is attached to the corresponding micro-motion platform by a suction cup, which is a precision vacuum suction cup.

[0030] The projection optics assembly is fixed in front of the white reference plate 1 and is used to receive light from the three color channels reflected by the red LCoS chip 5, the green LCoS chip 6 and the blue LCoS chip 7, and to project the resulting feature point array image corresponding to the red channel, green channel and blue channel respectively onto the projection receiving surface. Specifically, the projection optical components include a projection lens 2, a polarizing beam splitter 3, and an X-Cube beam combiner 4. The polarizing beam splitter 3 is positioned between the exit surface of the X-Cube beam combiner 4 and the projection lens 2. The incident light emitted by the white light source 8 is guided by the polarizing beam splitter 3 to the X-Cube beam combiner 4. After being decomposed into three monochromatic beams of red, green, and blue by the X-Cube beam combiner 4, the light shines on the red LCoS chip 5, the green LCoS chip 6, and the blue LCoS chip 7, respectively. The light carrying image information reflected by the three chips returns to the center of the X-Cube beam combiner 4 and converges. The converged full-color image beam passes through the polarizing beam splitter 3 and enters the projection lens 2.

[0031] The observation camera 10 and the projection optical assembly are mounted on the same side. The observation camera 10 is fixed in front of the white reference plate 1, and its optical axis forms a certain angle with the projection optical path. During system assembly, the observation camera 10 establishes the conversion relationship between its pixel array direction and the absolute horizontal or vertical direction of the system through calibration, and is used to acquire the feature point array image projected on the white reference plate 1 after assembly.

[0032] The central processing unit 17 is electrically connected to the six-degree-of-freedom micro-motion platform, the red LCoS chip 5, the green LCoS chip 6, the blue LCoS chip 7, and the observation camera 10, respectively, and is used to control timing, process images, and calculate pose. The central processing unit 17 is configured as follows: Control the red LCoS chip 5, green LCoS chip 6, and blue LCoS chip 7 to light up sequentially in a time-division manner, and control them to display a preset feature point array image; The system receives and processes feature point array images projected by each color channel from the observation camera 10. The red channel is used as the reference channel, and the green and blue channels are used as non-reference channels (in this embodiment, the red channel is used as the reference channel, but the green or blue channel can also be used as the reference channel). The system calculates the six-degree-of-freedom relative deviation of the green and blue channels with respect to the red channel, based on the current pose of the red channel. The calculated parameters of the six-degree-of-freedom relative deviation are converted into driving commands for the six-degree-of-freedom micro-motion platform, and the green and blue channels are adjusted in a closed loop to make their feature point array image coincide with the red channel across the entire frame. The red LCoS chip 5, green LCoS chip 6, and blue LCoS chip 7 are controlled to light up simultaneously. The superimposed images of the three colors are collected for overlap verification. After the verification is passed, the three six-degree-of-freedom micro-motion platforms are fixed.

[0033] See Figure 2 The present invention also discloses an automated optical coupling method for a chip in a 3LCoS projection system, comprising the following steps: Step S1: Fix the red LCoS chip 5, green LCoS chip 6 and blue LCoS chip 7 to their respective six-degree-of-freedom micro-motion platforms, and place the white reference plate 1 in front of the projection optical assembly as the projection receiving surface.

[0034] Step S2: Control the six-degree-of-freedom micro-motion platform to sequentially move the red LCoS chip 5, green LCoS chip 6, and blue LCoS chip 7 to preset initial spatial positions. These initial positions are pre-calibrated based on the geometry and optical design parameters of the X-Cube combining prism 4, ensuring the chips are within the adjustment range of the micro-motion platform and providing a reasonable starting state for subsequent closed-loop adjustments. This step allows for some deviation; residual errors will be eliminated through subsequent closed-loop adjustments. Step S3: In sequence, turn on the red LCoS chip 5, the green LCoS chip 6, and the blue LCoS chip 7 in a time-division manner, and control them to display the preset feature point array image of the corresponding color channel. The feature point array image covers the effective display area of ​​the chip.

[0035] First, the red LCoS chip is illuminated, and it is controlled to display a preset N×M array feature pattern (such as a crosshair or a dot array, N≥5, M≥5), which covers the effective display area of ​​the chip. After the red chip projection stabilizes, step S4 is executed to acquire the image. Subsequently, the green LCoS chip and the blue LCoS chip are illuminated in sequence, and the above projection and acquisition process is repeated to obtain the feature dot array images of each of the three color channels.

[0036] Step S4: Acquire feature point array images of each color channel projected onto the white reference plate 1 using the observation camera 10.

[0037] Step S5: Process the three feature point array images acquired respectively (preprocess the acquired original images, including: grayscale conversion, binarization, filtering and denoising, connected component analysis, to extract the effective regions of each feature point). This invention adopts a relative alignment strategy, with the red channel as the reference channel and the green and blue channels as non-reference channels. The current pose of the red channel is used as the reference to calculate the six degrees of freedom relative deviation of the green and blue channels with respect to the red channel. The deviation calculation is performed on the reference channel, and the pose of the reference channel is used as a reference. This includes: calculating the difference between the array centroid of the reference channel and the center of the camera image to characterize the translation deviation; calculating the angle between the fitted line of the first row of feature points of the reference channel array and the horizontal axis of the image to characterize the in-plane rotation deviation; and adjusting the translation and in-plane rotation of the chip corresponding to the reference channel according to the difference and the angle, allowing for a certain error tolerance, until the feature point array image projected by the reference channel is within the field of view of the camera.

[0038] The calculation of the six-degree-of-freedom relative deviations of the two non-reference channels relative to the reference channel includes: calculating the difference between the array centroids of the two non-reference channels and the array centroid of the reference channel as the relative translational deviation; calculating the difference between the array principal axis directions of the two non-reference channels and the array principal axis directions of the reference channel as the relative in-plane rotational deviation; and calculating the difference between the rate of change of the spacing of the two non-reference channels and the rate of change of the array spacing of the reference channel, which is then converted into the tilt angle deviation of the two non-reference channels relative to the reference channel through calibration mapping.

[0039] The following section first presents a general method for processing feature points, and then explains the deviation calculation method for each channel.

[0040] 5.1 Feature point center localization For images acquired by the observation camera, binarization and connected component analysis are first performed to extract the image region for each feature point. Subpixel-level center localization is then performed using either the gray-scale centroid method or the ellipse fitting method.

[0041] For a feature point in the i-th row and j-th column, its image coordinates are: ,in , (N≥5, M≥5).

[0042] 5.2 Calculation of row spacing and column spacing The column spacing between adjacent feature points in the i-th row (Horizontal direction): The row spacing between adjacent feature points in the j-th column (Vertical direction): The average column spacing of the i-th row is obtained by averaging the column spacings within the same row. : The average row spacing of the j-th column is obtained by averaging the row spacings within the same column. : 5.3 Calculation of Spacing Change Rate: Tilt (around the X-axis) analysis: Tilt primarily affects line spacing in the vertical direction. Calculate the rate of change of line spacing along the horizontal direction. : in, The average line spacing of the Mth row; This represents the average line spacing of the first row; This is the global average of all line spacings. This indicates that the line spacing on the right is greater than that on the left, corresponding to Inclined in the positive direction; Corresponding to the negative direction.

[0043] Tilt (around the Y-axis) analysis: Tilt primarily affects column spacing in the horizontal direction. Calculate the rate of change of column spacing along the vertical direction. : in, The average column spacing of the Nth column; The average column spacing of the first column; This is the global average of the column spacing.

[0044] 5.4 Calculation of the array centroid and principal axis directions Centroid coordinates of the array for: The principal axis direction (in-plane rotation angle) of the array is calculated as follows: extract the coordinates of the feature points in the first row of the array. The least squares method is used to fit a straight line, and the angle between the straight line and the horizontal axis (u-axis) of the image is obtained. Extract the coordinates of the first column of feature points in the array. The least squares method is used to fit a straight line, and the angle between the straight line and the vertical axis (v-axis) of the image is obtained. The average of the two values ​​is taken as the in-plane rotation angle. : 5.5 Deviation Calculation for the Red Channel The red channel serves as the baseline channel, and its adjustment target is: In-plane rotation ( ): Make the horizontal axis of the projected image parallel to the u-axis of the camera coordinate system; Translation (X, Y): Adjust its array center to the center of the camera's field of view; The tilt angle of the red channel ( , The current tilt orientation of the red channel is not calculated and is fixed as the reference for subsequent alignment of the green and blue channels. It should be noted that the translation and in-plane rotation adjustments of the red channel only need to ensure that the feature pattern is within the camera's field of view and its orientation is roughly upright, and a certain error tolerance is allowed.

[0045] (1) In-plane rotational deviation: The in-plane rotational bias of the red channel is relative to the camera coordinate system. The angle between the fitted line of the first row of feature points in the red array and the horizontal axis (u-axis) of the image is extracted. Then the in-plane rotational deviation for: Adjust the target to make The value approaches 0, meaning the horizontal axis of the projected image is parallel to the camera's u-axis. To improve accuracy, the angle between the fitted line from the first column of feature points and the vertical axis (v-axis) of the image can be used for verification, and the average of the two values ​​can be taken.

[0046] (2) Translational deviation: The translation deviation of the red channel is relative to the center of the camera's field of view. Let the image coordinates of the camera's field of view center be... ,but: in, These represent the horizontal and vertical coordinates of the centroid of the red channel array in the image, respectively. , These represent the pixel deviations of the red channel array centroid relative to the camera's field of view center in the horizontal and vertical directions, respectively. Through pre-calibrated pixel-physical space mapping coefficients (Unit: mm / pixel), converted to physical translation: 5.6 Deviation calculation for the green channel (based on red) The goal of adjusting the green channel is to make its pose consistent with that of the red channel. Therefore, the deviation calculation is relative to the current pose of the red channel.

[0047] (1) Relative translational deviation (ΔX, ΔY): Calculate the centroid of the green array With the red array centroid The difference: Through pre-calibrated pixel-physical space mapping coefficients Convert to physical translation: (2) Rotational deviation in relative plane: Calculate the principal axis direction of the green array With the red array main axis direction The difference: The specific calculation method is as follows: extract the principal axis direction angles of the red and green arrays respectively according to the method described in Section 5.4, and then subtract them to obtain the relative rotation deviation.

[0048] (3) Relative tilt angle deviation: Calculate the difference between the rate of change of the spacing of the green array and the rate of change of the spacing of the red array: in, , This represents the difference in line spacing rate between the green and red channels. Through a pre-defined mapping relationship, this difference in rate of change is converted into a relative tilt angle deviation. , The goal of adjustment is to make and The spacing rate approaches 0, meaning the rate of change of the green channel spacing is consistent with that of the red channel, thus ensuring that the green and red chips are parallel to each other.

[0049] 5.7 Deviation Calculation for the Blue Channel The blue channel uses the exact same calculation method as the green channel; simply replace the subscript G with B in the above formula.

[0050] 5.8 Calibration mapping from spacing change rate to relative tilt angle There is a geometric projection relationship between the rate of change of spacing and the tilt angle. In practical systems, this mapping relationship can be established through pre-calibration, and the calibration matrix can be fitted. , so that: For relative deviation , Similarly, it can be converted into relative tilt angle deviation using the same calibration matrix. , : The calibration process is completed once during system assembly, and the calibration parameters are stored in the memory of the central processing unit.

[0051] Step S6: Convert the calculated parameters of the six-degree-of-freedom relative deviation into driving commands for each six-degree-of-freedom micro-motion platform, and adjust the green and blue channels in a closed loop so that their feature point array image coincides with the red channel across the entire frame.

[0052] The closed-loop adjustment of the two non-reference channels includes: first, adjusting the translation and in-plane rotation of the reference channel to center its feature array and make its principal axis parallel to the horizontal axis of the coordinate system of the observation camera 10; then, using the reference channel as a reference, adjusting the six-degree-of-freedom pose of the two non-reference channels in sequence; repeating steps S3 to S5 until the relative deviation between the reference channel and the two non-reference channels meets the system's preset accuracy requirements.

[0053] Specifically, the following steps are included: 6.1 Red Channel Adjustment The central processing unit will calculate the in-plane rotation deviation of the red channel. Translational deviation , The commands are converted into driving instructions for a six-DOF micro-motion platform. The conversion process is based on a pre-calibrated kinematic model: by establishing the spatial transformation relationship between the chip coordinate system and the coordinate systems of each axis of the micro-motion platform, the deviation vector is decomposed into displacement or rotation of each axis. Specifically, this can be achieved using coordinate transformation matrices or lookup table interpolation methods.

[0054] The micro-motion platform adjusts the mounting base of the red LCoS chip according to the drive command to meet the following requirements: In-plane rotation angle Approaching 0 (the horizontal axis of the projected image is parallel to the camera's u-axis); Array centroid Approaching the center of the camera's field of view (Image centered) The tilt angle of the red channel remains unchanged, and its current tilt attitude is fixed as the reference for subsequent alignment of the green and blue channels. Adjustments to the red channel are allowed within a certain error tolerance, as long as the feature pattern is within the camera's field of view.

[0055] 6.2 Green channel adjustment (align with red) After completing the red channel adjustment, adjust the green channel based on the current pose of the red channel: Relative tilt angle adjustment: According to , Adjusting the green LCoS chip , The attitude was adjusted so that its spacing rate of change was consistent with that of the red channel; Relative in-plane rotation adjustment: According to Adjusting the green LCoS chip Adjust the angle so that its main axis direction aligns with the red channel; Relative translation adjustment: based on , Adjust the X and Y positions of the green LCoS chip so that its array centroid coincides with the red channel.

[0056] The adjustment of the three degrees of freedom can be done sequentially (e.g., first adjust the tilt, then the rotation, and finally the translation), or it can be done iteratively according to the magnitude of the deviation.

[0057] 6.3 Blue channel adjustment (align with red) The blue channel is adjusted using the same method as the green channel, with the red channel as the reference.

[0058] 6.4 Repetition and Convergence Repeat steps S3 to S5 until: The in-plane rotation angle and centroid offset of the red channel meet the system's preset accuracy requirements; The centroid deviation, rotational deviation, and spacing change rate deviation between the green, blue, and red channels are all less than the system's preset threshold. This threshold is pre-calibrated based on the imaging quality requirements and optical design parameters of the projection system to ensure that the three-color images achieve no visible overlap error and have sharp edges on the projection screen. When all conditions are met, the closed-loop adjustment phase is completed.

[0059] Step S7: Control the red LCoS chip 5, green LCoS chip 6 and blue LCoS chip 7 to light up simultaneously, collect the three-color superimposed image for overlap verification, and fix the three six-degree-of-freedom micro-motion platforms after the verification is passed.

[0060] After completing the closed-loop coupling adjustment in step S6, the process proceeds to the overlap verification stage, which confirms the final alignment accuracy of the three-color images. Verification includes two steps: visual observation and quantitative deviation detection.

[0061] (1) Direct observation by human eye The central processing unit controls the simultaneous illumination of three LCoS chips (red, green, and blue), projecting highly recognizable characteristic patterns (such as a crosshair or a dot array). An observation camera captures and overlays these images, allowing operators to visually assess whether the three-color patterns are essentially aligned. If a significant deviation is detected, supplementary adjustments are triggered.

[0062] (2) Quantitative deviation detection and fixation The central processing unit controls the red, green, and blue LCoS chips to light up sequentially in a time-division manner, each projecting the same N×M array feature pattern. The observation camera sequentially acquires three images, and the array coordinates of all feature points in each color channel are extracted using image processing algorithms.

[0063] For feature points at the same position (i, j) in the array, calculate the deviation distances between red and green, green and blue, and red and blue: Take the maximum value among the three as the three-color coincidence deviation: like If the overlap accuracy is less than the system's preset threshold, the coupling is considered complete, and the system outputs a success signal. At this point, the LCoS chip base can be fixed in the current position by the locking mechanism. Then, the vacuum adsorption of each set of precision vacuum chucks is turned off, the six-degree-of-freedom micro-motion platform is separated from the mounting base and removed, and can be used for coupling of the next set of chips.

[0064] The parts not described in detail in the above embodiments are existing technologies.

[0065] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A chip automated light coupling system for a 3LCoS projection system, characterized in that, include: A white reference plate (1) is used as the projection receiving surface; Three six-degree-of-freedom micro-motion platforms, each bearing a red LCoS chip (5), a green LCoS chip (6), and a blue LCoS chip (7) at its end. A projection optical component is fixed in front of the white reference plate (1) and is used to receive light from the three color channels reflected by the red LCoS chip (5), the green LCoS chip (6) and the blue LCoS chip (7), and to project the feature point array image formed corresponding to the red channel, the green channel and the blue channel onto the projection receiving surface. An observation camera (10) is mounted on the same side as the projection optics assembly to acquire the feature point array image projected by the white reference plate (1); A central processing unit (17) is electrically connected to a six-degree-of-freedom micro-motion platform, a red LCoS chip (5), a green LCoS chip (6), a blue LCoS chip (7), and an observation camera (10), respectively. The central processing unit (17) is configured as follows: Control the red LCoS chip (5), green LCoS chip (6), and blue LCoS chip (7) to light up in any order and display a preset feature point array image; The observation camera (10) receives the feature point array images projected by each color channel and processes them respectively. One color channel is taken as the reference channel and the other two color channels are non-reference channels. The deviation of the reference channel is calculated, and the pose of the reference channel is taken as the reference to calculate the six-degree-of-freedom relative deviation of the two non-reference channels relative to the reference channel. The calculated parameters of the six-degree-of-freedom relative deviation are converted into driving commands for the six-degree-of-freedom micro-motion platform, and the two non-reference channels are adjusted in a closed loop so that their feature point array images coincide with the reference channel across the entire frame. The red LCoS chip (5), green LCoS chip (6), and blue LCoS chip (7) are controlled to light up simultaneously, and the three-color superimposed images are collected for overlap verification. After the verification is passed, the three six-degree-of-freedom micro-motion platforms are fixed.

2. The system according to claim 1, characterized in that: The projection optical components include a projection lens (2), a polarizing beam splitter (3), and an X-Cube beam combiner (4). The polarizing beam splitter (3) is positioned between the exit surface of the X-Cube beam combiner (4) and the projection lens (2). The incident light emitted from the white light source is guided by the polarizing beam splitter (3) to the X-Cube beam combiner (4). After being decomposed into three monochromatic beams of red, green and blue by the X-Cube beam combiner (4), the light is respectively directed to the red LCoS chip (5), the green LCoS chip (6) and the blue LCoS chip (7). The light carrying image information reflected by the three chips returns to the center of the X-Cube beam combiner (4) and converges. The converged full-color image beam passes through the polarizing beam splitter (3) and enters the projection lens (2).

3. The system according to claim 1, characterized in that: The six-degree-of-freedom micro-motion platform includes a micro-motion platform, a suction cup, and a mounting base; the red LCoS chip (5), the green LCoS chip (6), and the blue LCoS chip (7) are fixed on their respective mounting bases, and each mounting base is attached to the corresponding micro-motion platform by the suction cup.

4. The system according to claim 1, characterized in that: The observation camera (10) is fixed in front of the white reference plate (1), and its optical axis forms a certain angle with the projection optical path. The observation camera (10) establishes the conversion relationship between its pixel array direction and the absolute horizontal / vertical direction of the system through calibration during system assembly.

5. The system according to claim 1, characterized in that, The central processing unit is further configured to: when using the current pose of one of the color channels as a reference, only perform translation and in-plane rotation adjustments on the six-degree-of-freedom pose corresponding to the reference, and align the six-degree-of-freedom poses of the other two color channels to the color channels corresponding to the reference.

6. A chip-based automated optical coupling method for a 3LCoS projection system, characterized in that, Includes the following steps: Step S1: Fix the red LCoS chip (5), green LCoS chip (6) and blue LCoS chip (7) on their respective six-degree-of-freedom micro-motion platforms, and place the white reference plate (1) in front of the projection optical assembly as the projection receiving surface; Step S2: Control the six-degree-of-freedom micro-motion platform to move the red LCoS chip (5), green LCoS chip (6) and blue LCoS chip (7) to the preset initial spatial position in sequence; Step S3: In any order, light up the three chips in turn, namely the red LCoS chip (5), the green LCoS chip (6) and the blue LCoS chip (7), and control them to display the feature point array image of the corresponding color channel. The feature point array image covers the effective display area of ​​the chip. Step S4: Acquire feature point array images of each color channel projected onto the white reference plate (1) using the observation camera (10); Step S5: Process the three feature point array images acquired respectively. Take one color channel as the reference channel and the other two color channels as non-reference channels. Calculate the deviation of the reference channel and calculate the six-degree-of-freedom relative deviation of the two non-reference channels relative to the reference channel based on the pose of the reference channel. Step S6: Convert the calculated parameters of the six-degree-of-freedom relative deviation into driving commands for the six-degree-of-freedom micro-motion platform, and adjust the two non-reference channels in a closed loop so that their feature point array image coincides with the reference channel across the entire frame. Step S7: Control the red LCoS chip (5), green LCoS chip (6) and blue LCoS chip (7) to light up simultaneously, collect the three-color superimposed image for overlap verification, and fix the three six-degree-of-freedom micro-motion platforms after the verification is passed.

7. The method according to claim 6, characterized in that, In step S5, the deviation of the reference channel is calculated, and the pose of the reference channel is used as a reference, including: The difference between the centroid of the array of the reference channel and the center of the camera image is calculated to characterize the translation deviation; the angle between the fitted line of the first row of feature points of the reference channel array and the horizontal axis of the image is calculated to characterize the in-plane rotation deviation; the chip corresponding to the reference channel is translated and rotated in-plane according to the difference and the angle until the feature point array image projected by the reference channel is within the field of view of the camera.

8. The method according to claim 6, characterized in that: In step S5, the six-degree-of-freedom relative deviations of the two non-reference channels relative to the reference channel are calculated, including: Calculate the difference between the array centroids of the two non-reference channels and the array centroid of the reference channel, as the relative translation deviation; Calculate the difference between the array principal axis direction of the two non-reference channels and the array principal axis direction of the reference channel, and use it as the in-plane rotational deviation. The difference between the rate of change of the spacing between the two non-reference channels and the rate of change of the array spacing between the reference channel is calculated and converted into the tilt angle deviation of the two non-reference channels relative to the reference channel through calibration mapping.

9. The method according to claim 6, characterized in that: In step S6, the closed-loop adjustment of the two non-reference channels includes: first, adjusting the reference channel by translation and in-plane rotation so that its feature array is centered and its principal axis is parallel to the horizontal axis of the coordinate system of the observation camera (10); then, with the reference channel as a reference, adjusting the six degrees of freedom pose of the two non-reference channels in sequence; repeating steps S3 to S5 until the relative deviation between the reference channel and the two non-reference channels meets the system's preset accuracy requirements.

10. The method according to claim 6, characterized in that: In step S7, the overlap verification specifically includes: extracting the coordinates of the three-color feature points, calculating the deviation distance between the feature points of each color channel, taking the maximum value as the three-color overlap deviation, and determining that the coupling is complete when the maximum value is less than a preset threshold.

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