X-cube and micro display screen alignment MTF detection method

Abstract

The application discloses an X-Cube and micro display screen alignment MTF detection system and method, the detection system includes loading platform, camera laser detection module, handling device, alignment device and MTF detection device; the loading platform is used for placing the X-Cube to be detected; the camera laser detection module is used for acquiring the attitude of X-Cube, including support seat, first camera laser assembly obliquely arranged on the support seat and second camera laser assembly vertically arranged on the support seat; the handling device moves X-Cube to first camera laser assembly, second camera laser assembly for detection respectively; the alignment device is used for installing micro display screen and adjusting the distance between micro display screen and the relative adhering surface; the MTF detection device carries out MTF image quality detection on the imaging of micro display screen through X-Cube, and through the mutual cooperation of each device, the lenses are screened before adhering, and the yield of subsequent products is improved.

Description

Technical Field

[0001] This invention belongs to the field of micro-display panel technology, specifically relating to an MTF detection system and method for aligning an X-Cube with a micro-display screen. Background Technology

[0002] Currently, microdisplay panels are widely used in various aspects of people's lives, becoming an indispensable part of daily life. They are widely used in micro-optical systems such as AR / VR devices, smart glasses, and medical endoscopes, with the beam combining prism and projection lens being an essential component. Measuring the MTF (Mean Transmission Frequency) of the three-color beam combining prism and projection lens combination is a crucial step in ensuring the final image quality of a color imaging system. Simultaneous measurement of the white light and monochromatic light MTF is necessary to comprehensively evaluate the system's resolution limits, color difference levels, and the performance of the beam combining device. With the rise of the micro-optical industry in AR / VR devices, smart glasses, and medical endoscopes, the types of micro-displays (MicroLEDs) are increasing, as is the demand for matching beam combining prisms and projection lenses. Therefore, the need for performance testing of beam combining prisms and projection lenses is becoming increasingly urgent. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an X-Cube and microdisplay MTF detection system and method.

[0004] The present invention adopts the following technical solution: An X-Cube and microdisplay MTF testing system is disclosed. The X-Cube includes a stereo light-combining prism, a mounting base on the top surface of the stereo light-combining prism, a lens in the mounting base, and three bonding surfaces on opposite sides and the bottom surface of the stereo light-combining prism for bonding with the microdisplay. The mounting base has a downwardly inclined positioning surface at its upper end, and three first positioning points are respectively set at three adjacent inner corners of the positioning surface. Three second positioning points are distributed circumferentially on the outer periphery of the lens. The system includes a loading platform, a camera laser inspection module, a conveying device, an alignment device, and an MTF testing device. The loading platform is used to place the X-Cube to be tested; A camera laser detection module for acquiring the attitude of an X-Cube includes a support base, a first camera laser assembly tilted on the support base, and a second camera laser assembly vertically mounted on the support base. The first camera laser assembly is perpendicular to the positioning surface. The first camera laser assembly performs height detection on three first positioning points on the positioning surface for leveling in the Tx and Ty axis directions. The second camera laser assembly detects the X-Cube to perform leveling in the R, Tx, Ty, X, and Y axis directions and to confirm the offset in the height direction. The transport device includes a six-axis moving platform and a gripping claw mounted on the six-axis moving platform for holding an X-Cube. The gripping claw moves the X-Cube to the first camera laser assembly and the second camera laser assembly for detection under the drive of the six-axis moving platform. The six-axis moving platform adjusts the orientation of the X-Cube according to the signal fed back by the first camera laser assembly or the second camera laser assembly to achieve a preset position. The alignment device is used to install the micro display screen and adjust the distance between the micro display screen and the opposite bonding surface. It includes two first alignment mechanisms that are respectively opposite to the two side bonding surfaces and a second alignment mechanism disposed between the two first alignment mechanisms and opposite to the bottom bonding surface. The MTF testing device performs MTF image quality testing on the microdisplay image image transmitted through the X-Cube, and includes a testing mount and an imaging colorimeter mounted on the testing mount above the second alignment mechanism.

[0005] Preferably, the first camera laser assembly includes a first detection camera tilted on the support base and a first laser height measuring instrument arranged parallel to the first detection camera on the support base. The first detection camera takes pictures of the three first positioning points of the X-Cube. The six-axis moving platform guides the gripper to move the X-Cube to the measurement point of the first laser height measuring instrument according to the signal fed back by the first detection camera. The height of the three first positioning points on the positioning surface is measured by the first laser height measuring instrument. The six-axis moving platform adjusts the stereo light combining prism in the Tx-axis and Ty-axis directions according to the signal fed back by the first laser height measuring instrument.

[0006] Preferably, the second camera laser assembly includes a second detection camera vertically mounted on the support base and a second laser height gauge mounted on the support base parallel to one side of the second detection camera. The second detection camera detects the X-Cube to confirm whether the R-axis direction of the X-Cube has shifted. If a shift occurs, the second detection camera repeats the detection. The six-axis moving platform adjusts the R-axis, Tx-axis, and Ty-axis directions according to the signal fed back by the second detection camera until the Tx-axis, Ty-axis, and R-axis directions are all leveled before leveling the X-axis and Y-axis directions. If there is no shift, the gripper moves the X-Cube to the measurement point of the second laser height gauge. The second laser height gauge measures the height of the three second positioning points. The six-axis moving platform adjusts the height of the second positioning points according to the signal fed back by the second laser height gauge.

[0007] Preferably, the first detection camera includes a first camera, a first lens, and a first light source arranged sequentially from top to bottom.

[0008] Preferably, the first alignment mechanism includes a first six-axis alignment platform, a first vacuum stage disposed on the first six-axis alignment platform for mounting the micro display screen, and a first alignment laser height measuring instrument disposed on the first six-axis alignment platform. The first alignment laser height measuring instrument performs distance measurement on the micro display screen on another first alignment mechanism.

[0009] Preferably, the second alignment mechanism includes a second six-axis alignment platform located between the two first six-axis alignment platforms and a second vacuum stage disposed on the second six-axis alignment platform for mounting the micro display screen. The micro display screen on the second vacuum stage is a G monochrome micro display screen, and the micro display screens on the two first vacuum stages are an R monochrome micro display screen and a B monochrome micro display screen, respectively.

[0010] Preferably, the MTF detection device includes a second alignment laser height measuring instrument vertically mounted on the detection seat and positioned opposite the second vacuum stage. The second alignment laser height measuring instrument measures the distance to the micro display screen on the second vacuum stage.

[0011] A method for MTF (Mean Transformation Factor) detection of X-Cube and microdisplay, based on any of the detection systems described above, specifically includes the following steps: Step 1: The gripper, in conjunction with the six-axis moving platform, moves the X-Cube on the loading platform to the measurement point of the second camera laser component for detection. The six-axis moving platform adjusts the R-axis direction based on the signal fed back from the second camera laser component. The gripper then moves the X-Cube to the measurement point of the first camera laser component for detection. The first camera laser component detects the height of the three first positioning points on the positioning surface to perform leveling in the Tx and Ty axes. The gripper continues to move the X-Cube to the second camera laser component for detection to perform leveling in the R, Tx, Ty, X, and Y axes and confirm the offset in the height direction, thus completing the X-Cube's attitude adjustment. Step 2: Fix three micro displays of different colors onto the two first alignment mechanisms and the second alignment mechanism respectively, and connect the three micro displays of different colors to the controller via ribbon cables. Among them, the R monochrome micro display and the B monochrome micro display are fixed onto the two first alignment mechanisms respectively, and the G monochrome micro display is fixed onto the second alignment mechanism. Step 3: The six-axis moving platform controls the gripper to move the X-Cube, whose attitude has been adjusted, to the detection position below the imaging colorimeter. Then, the distance between the two micro-displays of the two first alignment mechanisms and the relative bonding surface is adjusted to perform MTF value testing. Next, the distance between the micro-display on the second alignment mechanism and the relative bonding surface is adjusted to perform MTF value testing. Based on the obtained data, the defocus curves of the R monochrome micro-display, B monochrome micro-display, and G monochrome micro-display are obtained by using the experimental data fitting method.

[0012] As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are: the present application adjusts the posture of the X-Cube through the camera laser detection module, and obtains the MTF value of the three-color micro display screen in conjunction with the subsequent alignment device and MTF detection device, thereby obtaining the defocus curve. The lens is judged to be qualified based on the obtained three-color defocus curve, and the lens is screened before bonding, thereby improving the yield of subsequent products. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the detection system. Figure 2 This is a schematic diagram of the alignment device; Figure 3 This is a schematic diagram of the structure of the interconnected laser detection module; Figure 4 This is a schematic diagram of the transport device. Figure 5 This is a schematic diagram of the structure of the first alignment platform; Figure 6 This is a schematic diagram of the structure of the second alignment platform; Figure 7 This is a schematic diagram of the MTF detection device; Figure 8 This is a schematic diagram of the X-Cube structure; Figure 9 This is a schematic diagram of the structure of the first calibration block; Figure 10 This is a schematic diagram of the structure of the second calibration block; In the diagram: 1. Loading platform; 2. Camera laser inspection module; 3. Handling device; 4. Alignment device; 5. MTF inspection device; 6. X-Cube; 7. First calibration block; 8. Second calibration block; 11. Product slot; 12. Through-beam sensor; 21. Support base; 22. First camera laser assembly; 221. First inspection camera; 222. First laser height gauge; 223. First camera; 224. First lens; 225. First light source; 23. Second camera laser assembly; 231. Second inspection camera; 232. Second laser height gauge; 233. Second camera; 234. Second lens; 235. Second light source; 31. Six-axis moving platform; 32. Clamping jaw; 41. First alignment mechanism; 411. First six-axis alignment platform; 412. First vacuum stage; 413. First alignment laser altimeter; 42. Second alignment mechanism; 421. Second six-axis alignment platform; 422. Second vacuum stage; 51. Detection seat; 52. Imaging colorimeter; 53. Second alignment laser altimeter; 61. Stereoscopic beam combining prism; 62. Mounting seat; 63. Lens; 64. Fitting surface; 65. Positioning surface; 66. First positioning point; 67. Second positioning point; 71. Inclined surface; 72. First calibration hole; 81. Second calibration hole. Detailed Implementation

[0014] The present invention will be further described below through specific embodiments.

[0015] like Figures 1-10 As shown, the present invention discloses an X-Cube and micro-display screen alignment MTF detection system, including a loading platform 1, a camera laser detection module 2, a handling device 3, an alignment device 4, and an MTF detection device 5.

[0016] X-Cube6 includes a stereo light-combining prism 61, a mounting base 62 disposed on the top surface of the stereo light-combining prism 61, a lens 63 disposed in the mounting base 62, and three bonding surfaces 64 disposed on opposite sides and the bottom surface of the stereo light-combining prism 61 for bonding with the micro-display screen. The mounting base 62 has a downwardly inclined positioning surface 65 at its upper end, and three first positioning points 66 are respectively disposed at three adjacent inner corners of the positioning surface 65. The lens 63 has three second positioning points 67 distributed circumferentially on its outer periphery. The angle between the positioning surface 65 and the horizontal plane is 13.5 ± 0.5°.

[0017] The loading platform 1 is used to place the X-Cube6 to be tested. The top of the platform is equipped with multiple product slots 11 for placing the X-Cube6 and multiple through-beam sensors 12 for detecting whether the product slots 11 contain the X-Cube6.

[0018] The camera laser detection module 2 is used to acquire the attitude of the X-Cube6. It includes a support base 21, a first camera laser assembly 22 tilted on the support base 21, and a second camera laser assembly 23 vertically mounted on the support base 21. The first camera laser assembly 22 can be perpendicular to the positioning surface 65, that is, the angle between the first camera laser assembly 22 and the vertical direction is the same as the angle between the positioning surface 65 and the horizontal direction. The first camera laser assembly 22 performs height detection on the three first positioning points 66 on the positioning surface 65 to perform leveling in the Tx-axis and Ty-axis directions. The second camera laser assembly 23 detects the X-Cube6 to perform leveling in the R-axis, Tx-axis, Ty-axis, X-axis, and Y-axis directions and to confirm the offset in the height direction.

[0019] The handling device 3 includes a six-axis moving platform 31 and gripping claws 32 mounted on the six-axis moving platform 31 for holding the X-Cube6. The gripping claws 32, driven by the six-axis moving platform 31, move the X-Cube6 to the first camera laser assembly 22 and the second camera laser assembly 23 for detection. The six-axis moving platform 31 adjusts the orientation of the X-Cube6 according to the signals fed back by the first camera laser assembly 22 or the second camera laser assembly 23 to achieve a preset position. Specifically, the gripping claws 32 can be selected according to the gripping requirements of the X-Cube6.

[0020] The first camera laser assembly 22 includes a first detection camera 221 tilted on a support base 21 and a first laser height gauge 222 arranged parallel to the first detection camera 221 on the support base 21. The first detection camera 221 takes pictures of three first positioning points 66 of the X-Cube6. The six-axis moving platform 31 guides the gripper 32 to move the X-Cube6 to the measurement point of the first laser height gauge 222 based on the signal fed back from the first detection camera 221. The first laser height gauge 222 measures the height of each of the three first positioning points 66 on the positioning surface 65. The six-axis moving platform 31 then... The signal fed back by the laser altimeter 222 is used to level the stereo light combining prism 61 in the Tx and Ty axes. During this process, the controller fits the information of the three first positioning points fed back by the laser altimeter 222 into a plane, compares the obtained plane with the preset standard plane, and obtains the offset in the Tx and Ty axes. The six-axis moving platform 31 can then adjust the attitude of the X-Cube 6 according to the offset. Specifically, the first detection camera 221 includes a first camera 223, a first lens 224, and a first light source 225 connected from top to bottom. Furthermore, the first lens 224 adopts a CCTV lens, and the combination of the camera, light source, and lens is existing technology, which will not be described further here.

[0021] The second camera laser assembly 23 includes a second detection camera 231 vertically mounted on the support base 21 and a second laser height measuring instrument 232 mounted on the support base 21 parallel to one side of the second detection camera 231. The second detection camera 231 detects the X-Cube6 to confirm whether the R-axis direction of the X-Cube6 has deviated. If a deviation occurs, the second detection camera 231 repeats the detection. The six-axis moving platform 31 adjusts the R-axis, Tx-axis, and Ty-axis directions based on the signal fed back from the second detection camera 231, until the Tx-axis, Ty-axis, and R-axis directions are all leveled, and then the X-axis and Y-axis directions are leveled. If there is no deviation, the gripper 32 moves the X-Cube6 to the second laser height measuring instrument 232. At the measurement point, the height of the three second positioning points 67 is measured by the second laser height measuring instrument 232. The six-axis moving platform 31 adjusts the height of the second positioning points 67 according to the signal fed back by the second laser height measuring instrument 232. During this process, the controller fits the information of the three second positioning points 67 fed back by the second laser height measuring instrument 232 into a plane, compares the obtained plane with the preset standard plane, and obtains the offset in the Z-axis direction. The six-axis moving platform 31 can then adjust the attitude of the X-Cube6 according to the offset. Specifically, the second detection camera 231 includes a second camera 233, a second lens 234, and a second light source 235 connected from top to bottom. Furthermore, the second lens 234 adopts a CCTV lens, and the combination of the camera, light source, and lens is existing technology, which will not be described further here. The alignment device 4 is used to install the micro display screen and adjust the distance between the micro display screen and the opposite bonding surface 64. It includes two first alignment mechanisms 41 that are respectively opposite to the two side bonding surfaces and a second alignment mechanism 42 that is disposed between the two first alignment mechanisms 41 and opposite to the bottom bonding surface.

[0022] The first alignment mechanism 41 includes a first six-axis alignment platform 411, a first vacuum stage 412 mounted on the first six-axis alignment platform 411 for mounting the micro display screen, and a first alignment laser height measuring instrument 413 mounted on the first six-axis alignment platform 411. The first alignment laser height measuring instrument 413 measures the distance to the micro display screen on another first alignment mechanism. Specifically, the first alignment laser height measuring instrument 413 is mounted on the first six-axis alignment platform 411 with corresponding processed parts. The processed parts can be selected according to the installation requirements of the first alignment laser height measuring instrument 413, which will not be elaborated further here. Since the micro display screen on the first alignment mechanism 41 needs to be placed sideways on the corresponding first vacuum stage 412, the vacuum adsorption of the first vacuum stage 412 needs to be opened first before the micro display screen is placed. The first vacuum stage 412 will be fitted with a locking edge according to the shape of the micro display screen for positioning. Since the micro display screen is only for testing, it does not need to be moved after it is loaded.

[0023] The second alignment mechanism 42 includes a second six-axis alignment platform 421 located between the two first six-axis alignment platforms 411 and a second vacuum stage 422 mounted on the second six-axis alignment platform 421 for mounting the micro display screen. The micro display screen on the second vacuum stage 422 is a G monochrome micro display screen, and the micro display screens on the two first vacuum stages 412 are an R monochrome micro display screen and a B monochrome micro display screen, respectively.

[0024] MTF detection device 5 performs MTF image quality detection on the micro display screen imaged by X-Cube 6. It includes a detection seat 51, an imaging colorimeter 52 mounted on the detection seat 51 above the second alignment mechanism 42, and a second alignment laser height meter 53 vertically mounted on the detection seat 51 and opposite to the second vacuum stage 422. The second alignment laser height meter 53 measures the distance to the micro display screen on the second vacuum stage 422.

[0025] The six-axis moving platform 31, the first six-axis alignment platform 411, and the second six-axis alignment platform 421 specified in this application can all realize the adjustment of the X-axis, Y-axis, Z-axis, R-axis, Tx-axis, and Ty-axis. Moreover, the six-axis platform is a conventional technology in the prior art, and the specific structural composition and working principle will not be further described here.

[0026] A method for MTF (Mean Transformation Factor) detection of X-Cube and microdisplay, based on any of the detection systems described above, specifically includes the following steps: Step 1, X-Cube attitude adjustment: A. The clamping jaws, in conjunction with the six-axis moving platform, move the X-Cube on the loading platform to the measurement point of the second camera laser component for detection. The six-axis moving platform adjusts the R-axis direction according to the signal fed back by the second detection camera. After adjustment, the second detection camera takes a picture again to confirm until the R-axis direction is correct. B. The gripper holds the X-Cube and moves it to the detection position of the first detection camera to take a picture. Based on the image information fed back by the first detection camera, the six-axis moving platform is visually guided to move the X-Cube to the first laser height measuring instrument. The first laser height measuring instrument detects the height of the three first positioning points on the positioning surface to adjust the Tx-axis and Ty-axis directions. After adjustment, the six-axis moving platform moves the X-Cube to the first detection camera to take a picture. Based on the feedback image information, the six-axis moving platform is visually guided again to move the X-Cube to the measurement position of the first laser height measuring instrument for measurement and leveling again until it is level. C. The six-axis moving platform moves the gripper to the measurement point of the second detection camera, where it moves the X-Cube. The second detection camera checks the X-Cube to confirm whether its R-axis direction has shifted. If a shift occurs, the second detection camera repeats the check. The six-axis moving platform adjusts the R-axis, Tx-axis, and Ty-axis directions based on the feedback signal from the second detection camera, continuing this adjustment until the Tx-axis, Ty-axis, and R-axis directions are all leveled before leveling the X-axis and Y-axis directions. If there is no shift, the gripper moves the X-Cube to the measurement point of the second laser height gauge. The second laser height gauge measures the height of the three second positioning points, and the six-axis moving platform adjusts the height of these points based on the feedback signal from the second laser height gauge, thus completing the X-Cube's attitude adjustment. Step 2: Fix three micro displays of different colors onto two first vacuum platforms and a second vacuum platform respectively, and connect the three micro displays of different colors to the controller via ribbon cables. Among them, the R monochrome micro display and the B monochrome micro display are fixed on two first alignment mechanisms, and the G monochrome micro display is fixed on the second alignment mechanism. Step 3: The six-axis moving platform controls the gripper to move the X-Cube, whose attitude has been adjusted, to the detection position below the imaging colorimeter. Then, the two first six-axis alignment platforms adjust their movement relative to the first vacuum stage in the Y-axis direction to adjust the distance between the R monochrome microdisplay, B monochrome microdisplay and the relative bonding surface to perform MTF value testing. Next, the second six-axis alignment platform adjusts its movement relative to the second vacuum stage in the Z-axis direction to adjust the distance between the G monochrome microdisplay and the relative bonding surface to perform MTF value testing. Based on the obtained data, the defocus curves of the R monochrome microdisplay, B monochrome microdisplay and G monochrome microdisplay are obtained by experimental data fitting. The lens qualification is determined by obtaining the three defocus curves.

[0027] Before proceeding to step 1, the first camera laser assembly 21, the second camera laser assembly 22, the first alignment mechanism 41, the second alignment mechanism 42, and the MTF detection device 5 need to be calibrated using standard samples. The standard sample is an X-Cube with standard parameters. The first calibration block 7 is block-shaped, and its top surface has an inclined surface 71 with the same tilt angle as the positioning surface 65. The first calibration hole 72 is provided in the center of the inclined surface 71. The second calibration block 8 is block-shaped, and its top surface is flat. The second calibration hole 81 is provided in the center.

[0028] When calibrating the relative positions of the first detection camera and the first laser height measuring instrument, the first calibration block is fixed on the clamping jaws and moved to the first detection camera. The inclined surface of the camera is photographed to find the center position of the first calibration hole. Then, the first calibration block is moved to the measurement position of the first laser height measuring instrument. The first laser height measuring instrument is positioned at the edge of the first calibration hole using a six-axis moving platform. The three edge positions of the first calibration hole are recorded respectively. The center coordinates of the first calibration hole are calculated after coordinate fitting. Then, the center position of the first calibration hole photographed by the first detection camera and the center coordinates fitted by the first laser height measuring instrument are used for position calibration to determine the positional relationship between the first detection camera and the first laser height measuring instrument.

[0029] When calibrating the relative position of the second detection camera and the second laser height measuring instrument, the second calibration block is fixed on the clamping jaws and moved to the second detection camera to take a picture of the second calibration block and find the center position of the second calibration hole. Then, the standard sample is moved to the measurement position of the second laser height measuring instrument, and the second laser height measuring instrument is positioned at the edge of the second calibration hole by the six-axis moving platform. The three edge positions of the second calibration hole are recorded respectively, and the center coordinates of the second calibration hole are calculated after coordinate fitting. Then, the center position of the second calibration hole captured by the second detection camera and the center coordinates fitted by the second laser height measuring instrument are used for position calibration to determine the positional relationship between the second detection camera and the second laser height measuring instrument.

[0030] When calibrating the R-axis, X-axis, and Y-axis positions of the imaging colorimeter and the second detection camera, the standard sample is fixed on the clamping jaws. The six-axis moving platform moves the standard sample under the imaging colorimeter. A relay mirror is installed below the imaging colorimeter. The imaging colorimeter captures images of two bright spots on the standard sample. The R-axis offset angle of the axis system and the pixel coordinates of one of the bright spots are calculated. The six-axis W-axis of the standard sample is adjusted so that the R-axis offset angle is 0°. The six-axis moving platform is then moved to the second detection camera via X and Y-axis adjustments. The second detection camera captures images of the bright spots on the standard sample. The R-axis offset angle of the standard sample and the pixel coordinates of one of the bright spots are calculated and recorded. In this way, the R-axis, X-axis, and Y-axis of the imaging colorimeter and the second detection camera can be calibrated.

[0031] When calibrating the Tx and Ty axes of the imaging colorimeter and the standard sample, a reflecting mirror is installed at the lens end of the imaging colorimeter. First, using the imaging colorimeter as a reference, the pitch and yaw knobs of the collimator are adjusted so that the image coordinates of the crosshairs received by the collimator are (0, 0). After the collimator is adjusted, the standard sample is moved to the opposite side of the imaging colorimeter, so that the beam of the collimator hits the mirror surface of the standard sample. The Tx and Ty axes are adjusted by the six-axis moving platform so that the image coordinates of the crosshairs reflected by the contour block mirror received by the collimator are (0, 0). At this point, the Tx and Ty axis calibration between the imaging colorimeter and the standard sample is completed.

[0032] When calibrating the first laser height gauge with the standard sample along the Tx and Ty axes, the standard sample is fixed on the clamping jaws. The X and Y axes of the six-axis moving platform are adjusted so that the standard sample is located at the center of the first detection camera, which then takes a picture of the standard sample. Based on the calibrated positional relationship between the first detection camera and the first laser height gauge, the six-axis moving platform is adjusted to move the standard sample to the center of the first laser height gauge. Then, based on the image taken by the first detection camera, the first detection camera and the first laser height gauge are guided to move so that the first laser height gauge lasers onto the three first positioning points on the inclined surface of the standard sample and records the laser height. This calibrates the Tx and Ty axis references of the first laser height gauge and the standard sample.

[0033] The calibration of the imaging colorimeter and the standard sample's Z-axis and laser Z-axis references is performed as follows: the standard sample is fixed on the clamping jaws, and the six-axis moving platform is adjusted to bring the standard sample infinitely close to the imaging colorimeter. Then, the Z-axis is adjusted to move the standard sample 2 mm away from the imaging colorimeter. The six-axis moving platform is then adjusted to move the product to the second laser height measuring instrument, so that the second laser height measuring instrument lases onto the three second positioning points of the standard sample, and the laser values ​​at this time are recorded to complete the calibration.

[0034] When calibrating the second inspection camera with the standard product along the X and Y axes, the standard sample is fixed on the clamping jaws. The six-axis moving platform adjusts the X and Y axes to move the standard sample to the second inspection camera. The standard sample is photographed by the second inspection camera, and the center point of the contour is found through visual processing. The six-axis moving platform adjusts the X and Y axes so that the center of the contour recognized by the second inspection camera is the center of the field of view of the second inspection camera. This position is recorded as the test position of the calibrated standard sample.

[0035] During the alignment mechanism calibration, a standard sample is first used to level the two first six-axis alignment platforms and the second six-axis alignment platform. The R, B, and G monochrome microdisplays are connected to the controller via ribbon cables. The controller controls the illumination of the R, B, and G monochrome microdisplays. The R, B, and G monochrome microdisplays refract light through the stereo light combining prism on the X-Cube and are then projected by the micro-projection lens. The images are captured by the imaging colorimeter. At this time, the offset of the R, B, and G monochrome microdisplays relative to the X-Cube is calculated by a preset program and fed back to the two first six-axis alignment platforms and the second six-axis alignment platform. The two first six-axis alignment platforms and the second six-axis alignment platform adjust their respective X, Y, Z, R, Tx, and Ty axes. After the leveling is completed, the two first six-axis alignment platforms and the second six-axis alignment platform record the corresponding positions. In actual testing, it is only necessary to move the Z-axis slide of the second six-axis alignment platform and the Y-axis slide of the two first six-axis alignment platforms to change the distance between the G, R, and B monochrome microdisplays and the relative mating surfaces.

[0036] This application uses a camera laser inspection module 2 to adjust the posture of the X-Cube 6, and then uses the subsequent alignment device 4 and MTF inspection device 5 to obtain the MTF value of the three-color micro display screen, thereby obtaining the defocus curve. The obtained three-color defocus curve is used to determine whether the lens 63 is qualified. The lens 63 is screened before bonding to improve the yield of subsequent products.

[0037] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the specification of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. An X-Cube and microdisplay MTF alignment detection system, wherein the X-Cube includes a stereo light-combining prism, a mounting base disposed on the top surface of the stereo light-combining prism, a lens disposed in the mounting base, and three bonding surfaces disposed on opposite sides and the bottom surface of the stereo light-combining prism for bonding with the microdisplay; the upper end of the mounting base is provided with a downwardly inclined positioning surface, and three first positioning points are respectively disposed at three adjacent inner corners of the positioning surface; the outer circumference of the lens is provided with three second positioning points; characterized in that: It includes a loading platform, a camera laser inspection module, a handling device, an alignment device, and an MTF inspection device; The loading platform is used to place the X-Cube to be tested; A camera laser detection module for acquiring the attitude of an X-Cube includes a support base, a first camera laser assembly tilted on the support base, and a second camera laser assembly vertically mounted on the support base. The first camera laser assembly is perpendicular to the positioning surface. The first camera laser assembly performs height detection on three first positioning points on the positioning surface for leveling in the Tx and Ty axis directions. The second camera laser assembly detects the X-Cube to perform leveling in the R, Tx, Ty, X, and Y axis directions and to confirm the offset in the height direction. The transport device includes a six-axis moving platform and a gripping claw mounted on the six-axis moving platform for holding an X-Cube. The gripping claw moves the X-Cube to the first camera laser assembly and the second camera laser assembly for detection under the drive of the six-axis moving platform. The six-axis moving platform adjusts the orientation of the X-Cube according to the signal fed back by the first camera laser assembly or the second camera laser assembly to achieve a preset position. The alignment device is used to install the micro display screen and adjust the distance between the micro display screen and the opposite bonding surface. It includes two first alignment mechanisms that are respectively opposite to the two side bonding surfaces and a second alignment mechanism disposed between the two first alignment mechanisms and opposite to the bottom bonding surface. The MTF testing device performs MTF image quality testing on the microdisplay image image transmitted through the X-Cube, and includes a testing mount and an imaging colorimeter mounted on the testing mount above the second alignment mechanism.

2. The X-Cube and microdisplay alignment MTF detection system according to claim 1, characterized in that: The first camera laser assembly includes a first detection camera tilted on a support base and a first laser height measuring instrument arranged parallel to the first detection camera on the support base. The first detection camera takes pictures of three first positioning points of the X-Cube. The six-axis moving platform guides the gripper to move the X-Cube to the measurement point of the first laser height measuring instrument according to the signal fed back by the first detection camera. The height of the three first positioning points on the positioning surface is measured by the first laser height measuring instrument. The six-axis moving platform adjusts the stereo light combining prism in the Tx-axis and Ty-axis directions according to the signal fed back by the first laser height measuring instrument.

3. The X-Cube and microdisplay alignment MTF detection system according to claim 2, characterized in that: The second camera laser assembly includes a second detection camera vertically mounted on the support base and a second laser height gauge mounted on the support base parallel to one side of the second detection camera. The second detection camera detects the X-Cube to confirm whether the R-axis direction of the X-Cube has shifted. If a shift occurs, the second detection camera repeats the detection. The six-axis moving platform adjusts the R-axis, Tx-axis, and Ty-axis directions according to the signal fed back by the second detection camera until the Tx-axis, Ty-axis, and R-axis directions are all leveled before leveling the X-axis and Y-axis directions. If there is no shift, the gripper moves the X-Cube to the measurement point of the second laser height gauge. The second laser height gauge measures the height of the three second positioning points. The six-axis moving platform adjusts the height of the second positioning points according to the signal fed back by the second laser height gauge.

4. The X-Cube and microdisplay alignment MTF detection system according to claim 2, characterized in that: The first detection camera includes a first camera, a first lens, and a first light source arranged sequentially from top to bottom.

5. The X-Cube and microdisplay alignment MTF detection system according to claim 1, characterized in that: The first alignment mechanism includes a first six-axis alignment platform, a first vacuum stage for mounting a micro display screen on the first six-axis alignment platform, and a first alignment laser height measuring instrument on the first six-axis alignment platform. The first alignment laser height measuring instrument measures the distance to the micro display screen on another first alignment mechanism.

6. The X-Cube and microdisplay alignment MTF detection system according to claim 5, characterized in that: The second alignment mechanism includes a second six-axis alignment platform located between the two first six-axis alignment platforms and a second vacuum stage mounted on the second six-axis alignment platform for mounting the micro display screen. The micro display screen on the second vacuum stage is a G monochrome micro display screen, and the micro display screens on the two first vacuum stages are an R monochrome micro display screen and a B monochrome micro display screen, respectively.

7. The X-Cube and microdisplay alignment MTF detection system according to claim 6, characterized in that: The MTF detection device includes a second alignment laser height measuring instrument vertically mounted on the detection seat and positioned opposite the second vacuum stage. The second alignment laser height measuring instrument measures the distance to the micro display screen on the second vacuum stage.

8. A method for aligning an X-Cube with a microdisplay for MTF detection, characterized in that: The detection is performed using the detection system according to any one of claims 1 to 7, specifically including the following steps: Step 1: The gripper, in conjunction with the six-axis moving platform, moves the X-Cube on the loading platform to the measurement point of the second camera laser component for detection. The six-axis moving platform adjusts the R-axis direction based on the signal fed back from the second camera laser component. The gripper then moves the X-Cube to the measurement point of the first camera laser component for detection. The first camera laser component detects the height of the three first positioning points on the positioning surface to perform leveling in the Tx and Ty axes. The gripper continues to move the X-Cube to the second camera laser component for detection to perform leveling in the R, Tx, Ty, X, and Y axes and confirm the offset in the height direction, thus completing the X-Cube's attitude adjustment. Step 2: Fix three micro displays of different colors onto the two first alignment mechanisms and the second alignment mechanism respectively, and connect the three micro displays of different colors to the controller via ribbon cables. Among them, the R monochrome micro display and the B monochrome micro display are fixed onto the two first alignment mechanisms respectively, and the G monochrome micro display is fixed onto the second alignment mechanism. Step 3: The six-axis moving platform controls the gripper to move the X-Cube, whose attitude has been adjusted, to the detection position below the imaging colorimeter. Then, the distance between the two micro-displays of the two first alignment mechanisms and the relative bonding surface is adjusted to perform MTF value testing. Next, the distance between the micro-display on the second alignment mechanism and the relative bonding surface is adjusted to perform MTF value testing. Based on the obtained data, the defocus curves of the R monochrome micro-display, B monochrome micro-display, and G monochrome micro-display are obtained by using the experimental data fitting method.

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