An optical module assembly and adjustment testing method and device

Abstract

The present invention provides an optical module assembly and adjustment test method and device. The device sets a camera on the imaging optical path of the optical module to simulate the visual effect of the human eye, collects the imaging of the test legend displayed by the display device in the camera, and determines whether the display device reaches the predetermined position by the clarity index, optical axis offset index, and distortion index of the collected test legend image. By adjusting the position of the display device online until the design requirements of the quality index of the test legend image are met. The device can timely adjust the position of the display device according to the quality index of the test legend image captured by the camera, compensating to a certain extent for the adverse effects caused by the structural tolerance, assembly tolerance, and aberration of the optical module on the imaging quality of the optical module, which helps to improve the product yield and assembly efficiency.

Description

Technical Field

[0001] The present invention relates to the alignment and testing technology of optical modules, and particularly to an optical module alignment and testing method and device. Background Art

[0002] Modern computer technology, display technology, sensor technology and other scientific and technological advances have promoted the development of systems for AR (Augmented Reality) and VR (Virtual Reality) experiences. VR scenarios create a virtual information environment in a multi-dimensional information space, enabling users to have an immersive sense of presence and the ability to interact perfectly with the environment; AR scenarios apply virtual information to the real world, where the real environment and the virtual environment are superimposed on the same screen or space and exist simultaneously.

[0003] The principle of AR and VR display devices is to pull the near image generated by the display through an optical system (optical module) to a distant place and magnify it, almost filling the human field of view, thereby generating a sense of immersion. For products such as AR and VR glasses, their optical modules mainly include optical display devices, optical lens assemblies and brackets. To ensure good display effects of the products, strict alignment accuracy requirements need to be met between the components of the optical module. Existing optical module products generally ensure the structural accuracy of the products by controlling the processing accuracy of the above-mentioned optical components, ensure the assembly alignment accuracy through assembly jigs or manual processes, and finally eliminate unqualified products by detecting the imaging quality of the finished products, and ultimately achieve the quality control of the products.

[0004] Generally, the main factors leading to the alignment deviation of optical modules are the structural tolerances of components and the assembly tolerances during the assembly process, and both of these errors are not easy to eliminate; in addition, for optical components such as lenses, there are inevitably aberrations, and the existing assembly and testing based on mechanical alignment cannot overcome the influence of aberration factors on the final imaging effect. Therefore, the existing optical component alignment and testing processes and techniques often result in low product yield, low efficiency, poor product stability and consistency, soaring costs, and the current methods are not suitable for large-scale mass production. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an optical module alignment and testing method, including the following steps:

[0006] Step S1, placing the optical module main body at a predetermined position;

[0007] Step S2, placing the display device of the optical module at the initial position;

[0008] Step S3, adjusting the display device to the target position;

[0009] Step S4, fix the display device.

[0010] Optionally, in the above optical module assembly and alignment test method, before step S3, there is also step S5:

[0011] Adjust the camera (2) to the predetermined position of the camera, so that the optical axis of the camera (2) is parallel to the optical axis of the optical module and the distance between the two is within 5 mm; preferably, the optical axis of the camera (2) coincides with the optical axis of the optical module;

[0012] Set the parameters of the camera (2) to simulate the visual effect of the human eye.

[0013] Further, in the above optical module assembly and alignment test method, in step S5, the setting of the parameters of the camera (2) includes:

[0014] Adjust the focusing distance of the camera (2) to the target focusing distance;

[0015] Adjust the aperture value of the camera (2) so that the aperture value matches the pupil size of the human eye, and adjust the pupil position of the camera (2) to match the exit pupil position of the optical module.

[0016] Further, in the above optical module assembly and alignment test method, in step S5, the position of the camera (2) is calibrated by a reference hole (34) provided on the fixed seat (3), including the following steps:

[0017] The camera (2) takes an image of the reference hole (34), and adjusts the position of the camera (2) until the image of the reference hole (34) is a concentric circle, and at this time the camera (2) is in the predetermined position of the camera.

[0018] Further, in the above optical module assembly and alignment test method, step S3 also includes step S31:

[0019] Control the first adjustment mechanism (1) to adjust the position of the display device. The camera (2) sequentially collects images of the test legends displayed by the display device, calculates the imaging clarity index of the optical module to be assembled, and selects the position of the display device corresponding to the image with the optimal clarity value among the images of the test legends whose clarity index meets the design requirements as the first predetermined position.

[0020] Further, in the above optical module assembly and alignment test method, in step S31, the determination of the first predetermined position of the display device specifically includes the following steps:

[0021] Step S311, the first adjustment mechanism (1) drives the display device to move within the movement range along the normal direction of the display plane of the display device at a set step size;

[0022] Step S312: The camera (2) sequentially captures the images of the test legends displayed on the display device at each position passed through, which are imaged by the optical module, and simultaneously records the position corresponding to the image.

[0023] Step S313: Calculate the clarity index of each image of the test legend captured, and determine the movement position corresponding to the optimal clarity index as the marking position.

[0024] Step S314: Move the display device to the marking position, set the length direction of the display area of the display device as the X-axis, and the width direction of the display area as the Y-axis; the first adjustment mechanism (1) drives the display device to rotate along the X-axis and the Y-axis respectively within a preset range at a set angular step, and then repeat steps S312 and S313, and determine the movement position corresponding to the optimal clarity index as the first predetermined position.

[0025] Further, in the above optical module assembly and adjustment test method, in step S313, obtaining the marking position specifically includes:

[0026] Calculate the clarity values of the rows and columns of the images of the test legends captured respectively. Among the images where the clarity values of the edge rows and columns and the center rows and columns all meet the preset range, select the position corresponding to the image with the largest clarity value of the center rows and columns as the marking position.

[0027] Further, in the above optical module assembly and adjustment test method, in step S312, the recording of the position corresponding to the image is achieved through the following steps:

[0028] Automatically record through a processor (5), or manually record through the scale set on the first adjustment mechanism (1).

[0029] Further, in the above optical module assembly and adjustment test method, step S3 further includes step S32:

[0030] Calculate the optical axis offset index of the optical module when the display device is at the first predetermined position. If the optical axis offset index does not meet the design requirements, control the first adjustment structure (1) to adjust the position of the display device until the optical axis offset index meets the design requirements, and select the adjusted position of the display device as the second predetermined position.

[0031] Further, in the above optical module assembly and adjustment test method, in step S32, the formula for calculating the optical axis offset of the optical module is shown in formula (1):

[0032]

[0033] Further, in the above optical module assembly, adjustment and testing method, in step S32, when calculating the optical axis offset index of the optical module when the display device is at the first predetermined position according to formula (1), if the optical axis offset index does not meet the design requirements, the steps of adjusting the position of the display device include:

[0034] According to the obtained x offset and y offset, adjust the display device to the second preset position that meets the design requirements; preferably, the design requirements are that both the x offset and y offset are within ±30 pixels; more preferably, the design requirements are that both the x offset and y offset are within ±10 pixels.

[0035] Further, in the above optical module assembly, adjustment and testing method, step S3 further includes step S33:

[0036] Calculate the distortion index of the image formed by the optical module at the first predetermined position. If the distortion index does not meet the design requirements, control the first adjustment mechanism (1) to adjust the position of the display device. The camera (2) sequentially collects images of the test legends displayed by the display device. Among the images of the test legends that meet the design requirements for the distortion index, select the position corresponding to the image with the smallest distortion amount and the magnification meeting the design requirements as the third predetermined position of the display device.

[0037] Further, in the above optical module assembly, adjustment and testing method, in step S33, the obtaining of the third predetermined position of the display device specifically includes the following steps:

[0038] Step 331, the first adjustment mechanism (1) drives the display device to move along the length direction of the display device at a set step size. The camera (2) collects the images of the test legends displayed by the display device imaged by the optical module in the assembly; calculate the distortion index of each collected test legend image, and select the movement position corresponding to the test legend image with the smallest distortion amount and the magnification meeting the design requirements among the test legend images that meet the design requirements for the distortion index as the first position of the display device;

[0039] Step S332, the first adjustment mechanism (2) drives the display device to move along the width direction of the display device at a set step size. The camera (2) collects the images of the test legends displayed by the display device imaged by the optical module in the assembly; calculate the distortion index of each collected test legend image, and select the movement position corresponding to the test legend image with the smallest distortion amount and the magnification meeting the design requirements among the test legend images that meet the design requirements for the distortion index as the second position of the display device;

[0040] Step S333, compare the distortion indexes of the test legend images obtained by the display device at the first position and the second position, and select the position corresponding to the position of the test legend image with the smallest distortion amount and the magnification meeting the design requirements as the third predetermined position.

[0041] Further, in the above optical module assembly and adjustment test method, in step S33, calculating the distortion index of the optical module includes the following steps:

[0042] Select the characteristic region of the test legend and compare it with the corresponding characteristic region image of the image of the test legend displayed by the display device, and calculate the relative index or absolute index of the characteristic regions of the two, that is, the distortion index.

[0043] Further, in the above optical module assembly and adjustment test method, the distortion index includes distortion amount and magnification;

[0044] Select any quadrilateral feature in the test legend, and obtain the four vector side lengths of the corresponding quadrilateral of the image of the test legend. Then, the calculation formula of the distortion amount is shown in formula (2):

[0045]

[0046] Wherein, among the selected quadrilateral features, ab and cd are the vector lengths of the two vertical sides, and ac and bd are the vector lengths of the two horizontal sides; and / or

[0047] Select the proportional relationship between the distances of any two points in the image of the test legend displayed by the display device and the distances of the two corresponding points in the test legend image, and process to obtain the magnification.

[0048] Further, in the above optical module assembly and adjustment test method, in step S3, first execute step S31, then execute steps S32 and S33, and the order of steps S32 and S33 is not limited until the clarity index, optical axis offset index, and distortion index meet the design requirements. The target position of the display device is one of the first predetermined position, the second predetermined position, and the third predetermined position.

[0049] Further, in the above optical module assembly and adjustment test method, the test legend is a preset legend, and the preset legend is a graphic pattern formed by several rows and columns of solid circles, or a grid formed by line pairs, or horizontal and vertical lines, or a combination of solid circles and line pair grids, or a checkerboard pattern or a QR code.

[0050] The present invention also provides an optical module assembly and adjustment test device for performing the steps in the above optical module assembly and adjustment test method. The device includes: a fixed seat (3) and a camera (2), and the fixed seat has at least one reference for defining the position of the entrance pupil optical axis of the optical module main body.

[0051] Optionally, in the above device, the reference includes a cylinder or a cone, and a cylindrical through hole or a conical through hole matching the reference is provided on the optical module main body.

[0052] Optionally, in the above device, the reference is a plane, and the part on the optical module body that matches the reference plane fits against the reference plane;

[0053] The fixing base (3) is further provided with a limiting member for limiting the position of the optical module body. The limiting member cooperates with the component on the optical module body that matches the limiting member, so that the position of the optical module body is limited to be unable to rotate or only able to rotate around the optical axis of the optical module or translate along the optical axis of the optical module.

[0054] Optionally, in the above device, the reference includes a first reference (31), a second reference (32) serving as limiting members, and a third reference (33) provided on the surface of the fixing base (3). The first reference (31) and the second reference (32) are reference planes arranged at an angle, and both reference planes are perpendicular to the third reference (33).

[0055] In the above device, the angle is 50° - 120°, preferably 86°, 88° or 90°.

[0056] Further, in the above device, the fixing base (3) is further provided with a reference hole (34). The axis of the reference hole (34) is parallel to the entrance pupil optical axis of the optical module body and the distance between the two is not greater than 5 mm; preferably, the axis of the reference hole (34) coincides with the entrance pupil optical axis of the optical module body.

[0057] Further, the above device further includes a first adjustment mechanism (1) for adjusting the position of the display device. The first adjustment mechanism (1) is provided with a clamping mechanism, and one end of the clamping mechanism is provided with a picking part.

[0058] Optionally, in the above device, the picking part is any one of a clamping jaw, a suction cup, and a magnet.

[0059] Further, the above device includes a second adjustment mechanism (6) for adjusting the position of the camera (2). The second adjustment mechanism (6) is connected to the camera (2).

[0060] Further, the above device further includes a processor (5). The data interfaces of the camera (2) and the first adjustment mechanism (1) are respectively connected to the processor (5).

[0061] The present invention also provides an optical module assembly and adjustment test device for fixing a display device of an optical module to an optical module body, including:

[0062] A control module (10) that performs data interaction with the first adjustment mechanism (1) and is used to control the first adjustment mechanism (1) to adjust the position of the display device;

[0063] The image acquisition module (20) interacts with the camera (2) to obtain the image of the test legend displayed on the display device collected by the camera (2).

[0064] The calculation module (30) is signal-connected to the image acquisition module (20) and is used to calculate the clarity index, optical axis offset index, and distortion index characterizing the image quality of the test legend image.

[0065] The judgment module (40) is signal-connected to the calculation module (30) and is used to judge whether the clarity index, optical axis offset index, or distortion index of the test legend image meets the design requirements.

[0066] The predetermined position determination module 50 is signal-connected to the judgment module (40) and is used to select the image with the optimal index from the images in which the clarity index, optical axis offset index, or distortion index determined by the judgment module 40 meets the design requirements, and use the position of the display device corresponding to this image as the predetermined position.

[0067] The control module (10) is signal-connected to the judgment module (40), generates a control instruction according to the obtained judgment result, and transmits it to the first adjustment mechanism (1) to adjust the position of the display device.

[0068] Further, in the above optical module assembly and adjustment test device, the calculation module (30) includes:

[0069] The clarity index calculation module (301) is used to calculate the gradient algorithm value or gray scale statistical value characterizing the clarity of the test legend image according to the image clarity algorithm.

[0070] The optical axis offset index calculation module (302) is used to calculate the offset between the central feature point of the test legend image and the central feature point of the original test legend according to Equation (1) to characterize the optical axis offset index.

[0071] The distortion index calculation module (303) is used to calculate the distortion amount or magnification of the test legend image according to Equation (2) to characterize the distortion index of the optical module.

[0072] Further, in the above optical module assembly and adjustment test device, the distortion index calculation module (303) is specifically used for:

[0073] Select the four outermost feature points at the four corners of the test legend, and for each square formed by the four feature points at each corner, calculate the horizontal distortion amount and vertical distortion amount of the display device respectively according to Equation (2).

[0074] Select the proportional relationship between the distance between any two points in the image of the test legend displayed on the display device and the distance between the two corresponding points in the test legend image, and process to obtain the magnification.

[0075] Further, in the above optical module assembly and adjustment testing device, the control module (10) is specifically configured to control the first adjustment mechanism (1) to move from one end of the installation area corresponding to the display device along a set direction with a set step length, or to rotate clockwise or counterclockwise with a set angular step length on one side of a set rotation area with the center of the display device as the axis.

[0076] Further, in the above optical module assembly and adjustment testing device, the predetermined position determination module (50) is specifically configured to:

[0077] Select the position corresponding to the test legend image with the maximum clarity value within a specific range as the marked position; or

[0078] Among the images where the clarity values of the edge rows and columns and the center rows and columns meet a preset range, select the position corresponding to the image with the maximum clarity value of the center rows and columns as the marked position;

[0079] Among the images where the clarity difference at the symmetric positions of the test legend image meets a preset range, select the position of the display device corresponding to the image with the minimum clarity difference as the first predetermined position;

[0080] Among the test legend images where the optical axis offset index meets the design requirements, select the position of the display device corresponding to the image with the minimum optical axis offset of the test legend image as the second predetermined position;

[0081] Select the position of the display device corresponding to the image with the minimum distortion and magnification meeting the design requirements among the test legend images obtained in the length direction of the display device as the first position, select the position of the display device corresponding to the image with the minimum distortion and magnification meeting the design requirements among the test legend images obtained in the width direction of the display device as the second position, compare the distortions of the test legend images obtained at the first position and the second position, and select the position corresponding to the image with the minimum distortion and magnification meeting the design requirements as the third predetermined position.

[0082] Further, the above optical module assembly and adjustment testing device further includes a predetermined position verification module (60). The predetermined position verification module (60) is signal-connected to the predetermined position determination module (50) and the control module (10), and is specifically configured to: verify whether the clarity index, optical axis offset index, and distortion index of the test legend image collected by the camera (2) meet the design requirements when the display device is located at the predetermined position obtained by the predetermined position determination module (50); if all meet the design requirements, then this position is the final predetermined position of the display device; otherwise, re-determine the movement range before and / or after and / or left and right at this predetermined position, and send the re-determined range to the control module (10) to re-adjust the position of the display device.

[0083] With the above solution, the present invention has the following technical effects: The present invention uses a camera to simulate the imaging effect of the human eye. The optical parameters of the camera are close to those of the human eye, ensuring that the imaging effect is consistent with that of the human eye and making the imaging meet the comfort of the human eye. The camera collects image quality indicators such as the clarity, optical axis offset, and distortion index of the test legend image in real time. According to the obtained image quality indicators of the test legend, the position of the display device is adjusted in real time through the first adjustment mechanism to compensate for the adverse effects on the imaging quality caused by the structural tolerances and assembly tolerances of other optical components of the optical module, ensuring good imaging quality. The test of the optical module is completed during assembly, improving the product yield and the finished product assembly test efficiency, and ensuring the consistency of the optical module products. The assembly and adjustment test device of the present invention is simple to operate, stable and reliable, and meets the mass production requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1A is a schematic diagram of the imaging structure of the optical module applied to the AR glasses;

[0085] Figure 1B is an application scenario example of the optical module assembly and adjustment test method of the present invention;

[0086] Figure 2 is a block diagram of an embodiment of the optical module assembly and adjustment test device of the present invention;

[0087] Figures 3A to 3E is a test legend for testing the imaging quality of the optical module of the present invention;

[0088] Figure 4A-1 、 Figure 4B and Figure 4C are characteristic examples of the recognized test legend;

[0089] Figure 4A-2 is a superimposed schematic diagram of the center of the circle of one of the test legends and the center of the circle recognized by the image collected by the camera;

[0090] Figure 5A is the clarity curve of the test legend image in the vertical direction;

[0091] Figure 5B is the image clarity curve of the test legend image in the horizontal direction;

[0092] Figure 6 is a trapezoidal distortion schematic diagram of the square feature recognized by the test legend image;

[0093] Figure 7 is an overall schematic diagram of an embodiment of the assembly and adjustment test device of the present invention;

[0094] Figure 8 is a partial structure example of the assembly and adjustment test device of the present invention.

[0095] The reference signs in the figure are indicated as follows:

[0096] 01 - Optical arc piece, 02 - Optical flat piece, 03 - Display device, 04 - Reference plane, 05 - Normal plane, 06 - Bracket;

[0097] 1 - First adjustment mechanism; 2 - Camera;

[0098] 3 - Fixed seat, 31 - First reference; 32 - Second reference; 33 - Third reference, 34 - Reference hole;

[0099] 4 - Base; 5 - Processor; 6 - Second adjustment mechanism;

[0100] 10 - Control module, 20 - Image acquisition module, 30 - Calculation module, 40 - Judgment module, 50 - Predetermined position determination module, 60 - Predetermined position verification module. Detailed implementation manners

[0101] Aiming at the problem that the existing assembly and testing based on mechanical alignment standards cannot overcome the influence of aberration factors on the final imaging effect, the present invention provides an optical module assembly adjustment and testing method and device. In this method, the display device in the optical module is installed at a predetermined position relative to the main body of the optical module. The display device receives and displays the signal of the test legend, and the test legend is imaged in the human eye through the optical path of the optical module. The installation accuracy of the display device affects the imaging quality of the human eye. The device is provided with a camera on the imaging optical path of the optical module to simulate the visual effect of the human eye, collect the image of the test legend displayed by the display device in the camera, judge whether the installation position of the display device is the predetermined position according to the image quality index of the collected test legend, and adjust the position of the display device in time through the clarity index, optical axis offset index and distortion index of the obtained test legend image until the predetermined index design requirements are met. The device can adjust the position of the display device in time according to the image quality index captured by the camera, compensate to a certain extent for the adverse effects caused by the structural tolerance, assembly tolerance and aberration of the optical module on the imaging quality of the optical module, and is helpful to improve the product yield and assembly efficiency.

[0102] It should be noted that in the following embodiments of the present invention, the initial position does not refer to the position that enables the optical module to achieve the best performance or the best imaging quality of the optical module. The predetermined position refers to the position that can make the performance or imaging quality of the optical module reach the relatively best among all the involved positions. Among them, the first predetermined position to the third predetermined position are only defined for the convenience of describing the positions in the operation steps. "First" to "third" do not represent an order and do not have other limiting meanings. In addition, the design requirements mentioned in the present invention refer to the clarity index, optical axis offset index, and distortion index requirements of the image of the test legend displayed on the display device captured after the display device in the optical module is adjusted to the predetermined position. Due to different accuracy requirements in different application scenarios, the clarity index, optical axis offset index, and distortion index requirements are also different. The present application does not limit the specific numerical range, and those skilled in the art should be able to understand the meaning of the design requirements.

[0103] The test legend is a graphic pattern (pattern) specially designed to facilitate the observation and calculation of the clarity index, optical axis offset index, and distortion index of the image formed by the optical module. The test legend of the present invention can be a graphic pattern formed by a combination of squares or vertical and horizontal lines or a combination of solid circles and line pairs formed by several rows and columns of solid circles or line pairs (see Figures 3A to 3E ), or a graphic pattern formed by a checkerboard or a QR code; preferably, it is a graphic pattern formed by a combination of squares or vertical and horizontal lines or a combination of solid circles and line pairs formed by odd-numbered rows and columns of solid circles or line pairs in the technical navigation. Of course, the method and device of the present invention are not limited to this test legend, and other suitable test legends can also be used.

[0104] The following will describe the optical module assembly and adjustment test method and device of the present invention in detail with reference to the accompanying drawings and examples.

[0105] Method

[0106] The present invention provides an optical module assembly and adjustment test method. Taking the AR glasses shown in FIG. 1 as an example, the method and the specific assembly and adjustment test process of the present invention will be described. Of course, the application of the method of the present invention is not limited to the optical module of this structure, and it can be easily applied to other structures of optical modules by changing the local structure.

[0107] As Figure 1A shown, the optical module includes:

[0108] The optical arc piece 01 is an aspherical concave mirror with reflection and transmission functions. A normal plane (the plane where the optical axis is located) 05 is formed along the concave top surface thereof, and the human eye is located on the normal plane 05.

[0109] The optical flat 02 is a beam splitter with reflection and transmission functions. It is located in front of the human eye. The angle between the optical flat 02 and the reference plane 04 of the optical module (i.e., the fixed angle of the optical flat 02) is determined by the optical system design;

[0110] The display device 03 is arranged parallel to the reference plane 04 of the optical module. The reflecting surface of the optical flat 02 faces the optical arc 01 and the display device 03. The reflecting surface of the optical arc 01 is located on the concave side facing the human eye.

[0111] The optical module projects the light emitted by the display device 03 onto the optical flat 02 serving as a beam splitter. The optical flat 02 reflects a part of the light. The reflected light is projected onto the inner concave side of the optical arc 01, and then reflected and passes through the optical flat 02 to form an image in the human eye. At the same time, the external light passes through the optical arc 01 and the optical flat 02 and enters the human eye, enabling the user of the AR glasses to simultaneously see the physical objects in the real world and the digital images generated by the display device 03, realizing the function of augmented reality.

[0112] The alignment process of the display device 03 is an important step in the alignment process of the optical module in the AR glasses. Obviously, the optical arc 01, the optical flat 02, and the display device 03 need to satisfy a certain spatial position relationship to achieve the above functions. In one embodiment, this spatial position relationship is ensured by the bracket 06. In this case, the bracket 06 is pre-designed to have a reference or components that cooperate with the reference, so that the optical arc 01, the optical flat 02, and the display device 03 can be attached to the bracket 06 relative to the reference in a predetermined positional relationship. In this way, the spatial position relationship among the optical arc 01, the optical flat 02, and the display device 03 is determined. In the embodiment shown in Figure 1, the bracket 06 is a cylindrical frame structure with a triangular cross-section. The reference plane 04 is set on one side frame of the bracket 06. First, the optical arc 01 is precisely fixed on one side frame of the bracket 06 relative to the reference plane 04, then the optical flat 02 is precisely fixed on the other side frame of the bracket 06 at a preset angle relative to the reference plane 04, and finally the display device 03 is installed on the side where the reference plane 04 of the bracket 06 is located.

[0113] According to the above imaging principle, after the optical arc 01 and the optical flat 02 are fixed on the bracket 06, the optical axis of the system is determined. When the virtual image distance is set, the optimal position of the display device 03 is also fixed accordingly. If the installation and adjustment position of the display device 03 deviates from the predetermined position, it may be combined with the installation and adjustment errors of other components (the optical arc 01 and the optical flat 02) to cause imaging distortion (such as trapezoidal distortion), and at the same time, it will affect the imaging clarity and reduce the imaging quality; if the installation and adjustment consistency cannot be guaranteed, it will also reduce the alignment yield of the subsequent binocular adjustment of the AR glasses.

[0114] Figure 1B This is an application scenario example of the optical module assembly, adjustment and testing method of the present invention. As Figure 1B shown, in this embodiment, the hardware used in the optical module assembly, adjustment and testing method includes a first adjustment mechanism 1, a camera 2, and a processor 5, where:

[0115] Set the length direction of the display area of the display device 03 as the X-axis direction, and the width direction of the display area as the Y-axis direction.

[0116] In Figure 1B the shown embodiment, the first adjustment mechanism 1 includes an adjustment platform and an operating arm arranged on the adjustment platform. The adjustment platform has moving drive mechanisms in the front-back, left-right, and vertical directions, as well as rotating drive mechanisms for rotating around the X-axis, Y-axis, and vertical Z-axis, and can realize six-dimensional adjustments of the front-back movement, left-right movement, height adjustment of the display device 03, and rotation around the X-axis, Y-axis, and Z-axis. The operating arm is arranged on the adjustment platform. The operating arm can be a rod with a telescopic function, and its end is provided with a structure for fixing the display device, such as an adhesive table, a clamping end, or an adsorption buckle for bonding, clamping, or adsorbing the display device 03. The adjustment platform can drive the operating arm to perform translational and rotational movements.

[0117] In another embodiment, the operating arm is provided with a clamping mechanism, and one end of the clamping mechanism is provided with a picking part. Further, the picking part can be a magnet.

[0118] The camera 2 is placed at Figure 1A the position of the human eye as shown, and by simulating the visual effect of the human eye, the image of the virtual image formed by the image displayed on the display device 03 in the lens of the camera 2 is captured, and whether the display device 03 is adjusted to a predetermined position (that is, the position where the optical performance of the optical module is relatively optimal or the position where the imaging quality of the optical module is relatively optimal) is judged by analyzing the quality of this image.

[0119] The camera 2 is arranged on a camera bracket. The position of the camera bracket is adjusted to the predetermined position of the camera, so that the camera 2 is located on the theoretical optical axis of the optical module (that is, Figure 1A on the normal plane 05 of the optical arc piece 01 in

[0120] In one embodiment, the data interfaces of the camera 2, the display device 03, and the first adjustment mechanism 1 are all connected to the processor 5. The processor 5 sends a test legend (preset legend) to the display device 03 for display. The light emitted by the test legend displayed on the display device 03 enters the camera 2 through the optical path of the optical module for imaging. The image signal captured by the camera 2 is transmitted to the processor 5 for analysis and processing, extracting and calculating the indicators characterizing the image quality, and controlling the first adjustment mechanism 1 to adjust the position of the display device according to the obtained indicators so that the image clarity indicator, the optical axis offset indicator, and the distortion indicator meet the design requirements; or the processor 5 generates a control instruction according to the obtained image quality indicator and sends it to the drive mechanism of the adjustment platform to drive the manipulator to adjust the display device 03 to a predetermined position (i.e., the position where the optical performance of the optical module is relatively optimal or the position where the imaging quality of the optical module is relatively optimal).

[0121] The indicators of image quality mainly include clarity, optical axis offset, and distortion indicators, where:

[0122] The clarity indicator of the image is an important indicator to measure the quality of the image, which can correspond well to people's subjective feelings. A lower clarity indicator is manifested as a blurred image.

[0123] For Figure 3C and Figure 3E the test legend images shown, calculate the clarity of the test images respectively according to the rows and columns where the solid circles are located. In this embodiment, there are five rows and five columns in total, and they are respectively plotted in the coordinate systems of column sequence - clarity value and clarity value - row sequence, as shown in Figure 5A and Figure 5B shown. Adjust the position of the display device 03 through the first adjustment mechanism 1 so that the image clarity shows a trend of being high in the center and low around, meeting the clarity requirements for AR or VR optical module imaging.

[0124] In the present invention, when the positions of the optical module main body and the camera 2 have been adjusted in place, the image clarity is related to the installation position of the display device 03 in the optical module. According to the object-image relationship, the installation position (position of the object) of the display device 03 on the bracket 06 determines the position of its projected virtual image and the tilt angle of the image plane (position of the image). The distance of the display device 03 from its installation surface (relative to the installation position of the optical module main body) changes the position of the object in the optical system, and its image also changes accordingly. At this time, the image captured by the camera 2 will show a process of out-of-focus - in-focus - out-of-focus again. Reflected in the image clarity value, it first increases, then decreases, and there will be a peak in the middle. The position of the display device 03 corresponding to this peak is the predetermined position on the normal direction of the installation surface of the display device. Adjust the front-back and left-right tilts of the display device 03 so that the image clarity distribution is symmetric left and right (the judgment criterion is that the left-right clarity difference meets the design requirements, that is, the clarity difference at symmetric positions is less than the preset value).

[0125] The central offset of the image can reflect the offset of the optical axis of the captured image. The characteristic point positions of the test legends displayed by the display device 03 (for example, Figure 3A and Figure 3B for the test legend, the intersection points of the selection lines of the test legend with the grid are taken as characteristic points, Figure 3C and Figure 3E for the test legend, the center positions of the solid circles are taken as characteristic points, Figure 3D for the test legend, the intersection points of the horizontal and vertical lines are taken as characteristic points) and the corresponding characteristic points of the image captured by the camera 2 are respectively mapped into the same coordinate system (see Figure 4A-2 ). The offset of the characteristic points at the center of the image of the test legend is calculated as the central offset index. Of course, the test legend is not limited to the test legends described above, and other test legends that can describe the translation amount of the image center are applicable to this measurement method.

[0126] As Figure 4A-2 shown, the X-axis direction corresponds to the length direction (horizontal direction) of the display area of the display device 03, and the Y-axis direction corresponds to the width direction (vertical direction) of the display area of the display device 03. A coordinate system is established by taking a preset point (such as the center point of the display area) in the display area of the display device 03 as the origin. The preset point is generally the center point of the display area, or a certain characteristic point selected or preset in advance. The central characteristic points of the test legend and the central characteristic points of the obtained test legend image are mapped into the same coordinate system, and the optical axis offset is calculated as follows:

[0127]

[0128] According to the x offset and y offset, the display device is adjusted to a position that meets the design requirements of the optical axis offset. Preferably, the design requirements mean that both the x offset and y offset are within ±30 pixels; more preferably, the design requirements mean that both the x offset and y offset are within ±10 pixels.

[0129] Once the position of the display device 03 is offset, the image captured by the camera 2 will be distorted compared with the test legend (such as Figure 6 the trapezoidal distortion shown). Distortion is one of the important indicators for evaluating the imaging quality of the optical module, and trapezoidal distortion is a frequently occurring form of distortion.

[0130] The distortion index includes two indicators: the amount of distortion and the magnification.

[0131] The main reason for the distortion of the image captured by the camera 2 that simulates the human eye is that the projection optical axis of the display device 03 is not consistent with the optical axes of other optical components on the bracket 06. Specifically, the optical axis of the display device 03 is skewed, resulting in asymmetry of the images on the left and right or top and bottom sides of the projected image, presenting a trapezoidal distortion phenomenon.

[0132] The distortion index can be characterized by a relative index. For example, Figure 6 as shown, select any quadrilateral feature in the test legend, obtain the image of the corresponding quadrilateral in the test legend image, and the calculation method of the trapezoid distortion amount is as follows:

[0133]

[0134] Among them, in the selected quadrilateral feature, ab and cd are the vector lengths of the two vertical sides, and ac and bd are the vector lengths of the two horizontal sides. The magnification refers to the proportional relationship between the image presented by the optical module and the test legend image. The proportional relationship between the distance between any two points in the test legend displayed by the display device 03 and the distance between the corresponding two points in the test legend image can be selected and processed to obtain the magnification. The required range of magnification is usually 50 - 200 times. Preferably, the processor 5 of the present invention uses the preset legend as the test legend (see Figures 3A to 3E ) and sends it to the display device 03 for display. The light emitted by the test legend forms an image in the camera 2 through the optical path of the optical module. The camera 2 sends the image of the captured image to the processor 5, and the processor 5 analyzes and processes the image to obtain the image clarity data (see Figure 5A and Figure 5B ), the optical axis offset index and the distortion index, and adjusts the position of the display device 03 through the first adjustment mechanism 1 to make the image clarity, optical axis offset, distortion amount and magnification meet the design requirements.

[0135] The preset legend is an image pattern formed by several rows and columns of solid circles, or a grid formed by line pairs, or horizontal and vertical lines, or a combination of solid circles and line pair grids, or a checkerboard or a two-dimensional code (the two-dimensional code includes a rectangular coordinate two-dimensional code and a polar coordinate two-dimensional code). Preferably, odd rows and odd columns of solid circles are selected as the test legend, and the center position of the solid circle image fitting is less affected by the imaging error.

[0136] The optical module assembly and adjustment test device of the present invention compensates for the adverse effects of the structural tolerances and assembly tolerances of other optical components of the optical module on the imaging quality by detecting in real time the imaging indexes such as the clarity, optical axis offset, distortion amount and magnification of the image captured by the camera 2 simulating the human eye, and the processor 5 controls the first adjustment mechanism 1 to adjust the position of the display device in real time according to the obtained imaging quality indexes, ensuring good imaging quality, completing the test of the optical module while assembling, improving the product yield and the finished product assembly test efficiency, and ensuring the consistency of the optical module products.

[0137] Before the optical module assembly, adjustment and testing, there is also a camera calibration step: install the camera bracket at a predetermined reference position, install the camera 2 on the camera bracket, and adjust the position and parameters of the camera 2, that is, adjust the focusing distance of the camera 2 to the target focusing distance, adjust the aperture value of the camera 2 to be the same as the pupil size of the human eye, and make the exit pupil plane of the camera 2 match the entrance pupil plane of the optical module; the camera 2 sends the image of the test legend displayed on the display device to the processor 5, and the processor 5 extracts and calculates the imaging quality indicators of the optical module (including clarity, optical axis offset, distortion, and magnification), and adjusts the position of the display device according to the obtained imaging quality indicators.

[0138] Preferably, during the optical module assembly, adjustment and testing, with reference to Figure 7 and Figure 8 , the optical module body is installed on a fixing base 3. The fixing base 3 has at least one reference and a reference hole 34. The optical module body can be installed on the fixing base 3 relative to the reference, so that the entrance pupil optical axis of the optical module body is parallel to the axis of the reference hole 34 and the distance between them is not greater than 5 mm (preferably coincident). For example, the reference includes a cylinder or a cone, and the optical module body is provided with a part matching the reference, such as a cylindrical through hole or a conical through hole. As long as the optical module body is installed in matching with the reference, the position of the optical module body is uniquely determined, which is beneficial to the installation of the optical module body and ensures the consistency of its position; if the reference is a plane, the fixing base 3 is also provided with a limiting member, and the optical module body is provided with a component matching the limiting member, such as a first reference 31 and a second reference 32 perpendicular to each other (the installation space determined by the mutually perpendicular reference planes, as long as the optical module body is placed closely against the first reference 31 and the second reference 32), and the limiting member cooperates with the reference to determine the position of the optical module body. In this embodiment, the purpose of setting the reference hole 34 is to facilitate the calibration of the position of the camera 2. As long as it is ensured that the optical axis of the camera 2 is parallel to the axis of the reference hole 34 and the distance between them is not greater than 5 mm (preferably coincident), the camera 2 is adjusted to the predetermined position of the camera. The method of calibrating the position of the camera 2 through the reference hole 34 is: the camera 2 takes a picture of the reference hole, and the image of the reference hole 34 obtained by the camera 2 is a concentric circle, indicating that the optical axis of the camera 2 coincides with the axis of the reference hole 34.

[0139] Furthermore, the lens aperture of the camera 2 simulates the pupil of the human eye, and the photosensitive film of the camera 2 is equivalent to the retina of the human eye. Adjust the position of the camera 2 so that the optical axis of the camera 2 coincides with the optical axis of the optical module. At this time, the virtual image distance of the camera 2 is certain. Adjust the focusing ring of the camera 2 to adjust the focusing distance of the camera to the target focusing distance, and adjust the aperture value of the camera to be the same as the pupil size of the human eye. For example, the lens focal length is 8 mm and the F number is 2.0. At this time, the aperture size is 8 / 2 = 4 mm, which is close to the human eye.

[0140] According to the above analysis, an embodiment of the optical module assembly and adjustment test method of the present invention includes the following steps:

[0141] Place the optical module main body at a predetermined position, and place the display device at the initial position.

[0142] Place the optical module main body (for example, the optical arc piece 01 and the optical flat piece 02 mounted on the bracket 06) at a predetermined position, and mount the display device to the end of the operating arm and move it to the initial position. The initial position is not the position that optimizes the optical performance of the optical module. The predetermined position is the position that relatively optimizes the optical performance of the optical module among the involved positions. After the display device is placed at the initial position, the first adjustment mechanism 1 is also required to drive the display device 03 to continuously move near the initial position to adjust the display device to the predetermined position, so that the optical performance of the optical module reaches relatively optimal.

[0143] Control the first adjustment mechanism 1 to adjust the position of the display device. The camera 2 collects the images of the test legends displayed by the display device, calculates the imaging clarity index of the optical module to be assembled, and selects the position of the display device corresponding to the image with the optimal clarity value among the test legend images whose clarity index meets the design requirements as the first predetermined position.

[0144] Furthermore, the preset test legend can be Figures 3A to 3E the graphic pattern shown. The camera 2 sends the captured images of the test legend to the processor 5 for analysis and processing, and calculates the image clarity value according to the existing image clarity algorithm.

[0145] For Figure 1A and Figure 1B the optical modules shown, the specific adjustment steps of the imaging clarity index of the display device 03 are as follows:

[0146] 1. The first adjustment mechanism 1 drives the display device 03 to move along the normal direction of the display area of the display device 03 with a set step size;

[0147] 2. The camera 2 sequentially collects the images of the test legends displayed by the display device imaged by the optical module at each position passed, and records the position corresponding to the image at the same time;

[0148] 3. Calculate the clarity index of each collected image of the test legend, and determine the movement position corresponding to the optimal clarity index as the marked position;

[0149] 4. Move the display device to the marked position, set the length direction of the display area of the display device as the X-axis, and the width direction of the display area as the Y-axis; the first adjustment mechanism 1 drives the display device to rotate within a preset range along the X-axis and Y-axis at a set angular step, then repeat steps 2 and 3, and determine the movement position corresponding to the optimal clarity index as the first predetermined position.

[0150] In the above step 1, when the first adjustment mechanism 1 drives the display device 03 to move, the set step corresponds to the movement distance corresponding to each movement. For example, the movement step in the normal direction of the display plane of the display device is 0.1 mm; the movement direction is forward or backward, etc. Preferably, a variable step can be adopted. For example, the movement step at the position where the display device 03 is farther from the installation surface of the optical module is made larger, and the movement step at the place where the display device 03 is closer to the installation surface is made smaller.

[0151] In the above step 2, each time the first adjustment mechanism 1 moves, the position of the display device 03 carried by it will also change, so the imaging of the optical module to be assembled will also change. In this embodiment, for each position where the display device 03 moves, the image of the optical module to be assembled at this time is recorded, and the movement position corresponding to this image is recorded. Here, the recording tool can be the processor 5, and it can be recorded through the scale corresponding to the first adjustment mechanism 1.

[0152] In the above step 3, the clarity index of each image can calculate the clarity value corresponding to this image according to the image clarity algorithm. Among the images of the test legend displayed by the display device 03 obtained, the position corresponding to the image with the largest clarity value is selected as the marked position among the images of the test legend within the preset range. Optionally, using the image clarity algorithm to calculate the clarity values of the test images respectively according to the rows and columns where the feature points of the collected test legend images are located can better reflect the distribution of clarity. That is, among the images where the clarity values of the edge rows, columns and the center rows, columns meet the preset range, the position corresponding to the image with the largest clarity value in the center rows, columns is selected as the marked position.

[0153] In the above step 4, when the first adjustment mechanism 1 drives the display device 03 to rotate, the set angular step corresponds to the rotation angle corresponding to each movement. For example, the angular step is 0.1°, and the movement direction is clockwise or counterclockwise. When determining the optimal clarity index, it is also necessary to ensure that the clarity values of the upper, lower, left and right of the image have a certain symmetry, that is, select the symmetric row and column regions in the test legend and calculate their clarity values respectively, and require that the clarity difference at the symmetric positions is less than the preset value; then among the images where the clarity difference at the symmetric positions in the test legend image is less than the preset value, select the position of the display device corresponding to the image with the smallest clarity difference at the symmetric positions as the first predetermined position.

[0154] Calculate the optical axis offset index of the imaging of the optical module when the display device is at the first predetermined position. If the obtained optical axis offset index meets the design requirements, perform distortion adjustment; alternatively, distortion adjustment can be performed first and then the optical axis offset can be adjusted.

[0155] According to the obtained x offset and y offset, adjust the display device to the second preset position that meets the design requirements of the optical axis offset index; preferably, the design requirement is that both the x offset and the y offset are within ±30 pixels; more preferably, the design requirement is that both the x offset and the y offset are within ±10 pixels.

[0156] Select the central feature point of the image of the test legend and map it to the same coordinate axis as the central feature point of the test legend. According to Equation (1), calculate the offsets of the central feature point on the X-axis and Y-axis respectively, and thus obtain the optical axis offset.

[0157] The specific adjustment steps for the optical axis offset of the imaging of the display device 03 are as follows:

[0158] According to the obtained optical axis offset, the processor 5 generates a control instruction and sends it to the driving mechanism of the first adjustment mechanism 1 to drive the first adjustment mechanism 1 to adjust the positions of the display device 03 in the X-axis and Y-axis directions, that is:

[0159] If x and y are positive values, it indicates that the display device 03 has a positive offset of x in the X-axis and a positive offset of y in the Y-axis. Then, the first adjustment mechanism 1 moves the display device 03 backward by x in the X-axis and backward by y in the Y-axis;

[0160] If x and y are negative values, it indicates that the display device 03 has a negative offset of |x| in the X-axis and a negative offset of |y| in the Y-axis. Then, the first adjustment mechanism 1 moves the display device 03 forward by |x| in the X-axis and forward by |y| in the Y-axis;

[0161] If x is a positive value and y is a negative value, it indicates that the display device 03 has a positive offset of x in the X-axis and a negative offset of |y| in the Y-axis. Then, the first adjustment mechanism 1 moves the display device 03 backward by x in the X-axis and forward by |y| in the Y-axis;

[0162] If x is a negative value and y is a positive value, it indicates that the display device 03 has a negative offset of |x| in the X-axis and a positive offset of y in the Y-axis. Then, the first adjustment mechanism 1 moves the display device 03 forward by |x| in the X-axis and backward by y in the Y-axis.

[0163] Calculate the distortion index of the imaging of the optical module at the first predetermined position or the second predetermined position. If the distortion index does not meet the design requirements, control the first adjustment mechanism 1 to adjust the position of the display device. The camera 2 sequentially acquires images of the test legends displayed by the display device. Among the images of the test legends for which the distortion index meets the design requirements, select the position corresponding to the image with the smallest distortion amount and a magnification factor that meets the design requirements as the third predetermined position of the display device.

[0164] Select the quadrilateral feature formed by the four outermost feature points at the four corners of the recognized test legend (i.e., Figure 4A-1 , Figure 4B and Figure 4C the quadrilateral formed by the four corner feature points in

[0165] Select the ratio relationship between the distance between any two points in the image of the test legend displayed by the display device and the distance between the two corresponding points in the test legend image, and process to obtain the magnification factor. If the magnification factor is within the preset magnification range, it meets the design requirements of the distortion index.

[0166] The specific adjustment steps for the imaging distortion index of the display device 03 are as follows:

[0167] The first adjustment mechanism 1 drives the display device 03 to move along the length direction or the width direction of the display device 03 with a set step size, and the camera 2 acquires the image of the test legend displayed by the display device 03 imaged through the optical module in this assembly; calculate the distortion index of each acquired test legend image according to Equation 2). Among the test legend images that meet the design requirements of the distortion index, select the movement position corresponding to the test legend image with the smallest distortion amount and a magnification factor that meets the design requirements as the third predetermined position of the display device.

[0168] The execution order of the above steps for adjusting the optical axis offset amount and the steps for adjusting the distortion index is not limited. The target position of the display device is one of the first predetermined position, the second predetermined position, and the third predetermined position.

[0169] This method further includes a step for confirming a predetermined position, which is used to confirm whether the predetermined position of the display device is the target position (i.e., whether it is a position that meets the predetermined design requirements):

[0170] The test shows that the display device is located at the first predetermined position, the second predetermined position or the third predetermined position. Whether the clarity index, the optical axis offset index and the distortion index of the test legend image collected by the camera 2 meet the design requirements. If all meet the design requirements, this position is the final predetermined position of the display device; otherwise, re-determine the movement range of the display device before and / or after and / or left and right at the first predetermined position, the second predetermined position or the third predetermined position (usually this movement range is smaller than the previously determined movement range, for example, the movement range of the display device is determined to be half of the original range), and repeat the above steps until the imaging clarity, the optical axis offset and the distortion index of the optical module all meet the design requirements.

[0171] Apparatus

[0172] Reference Figure 7 and 8 According to the present invention, an optical module assembly and adjustment test device is provided for performing an optical module assembly and adjustment test method, at least including: a fixed seat 3 and a camera 2. The fixed seat 3 is provided with at least one reference. The optical module main body is mounted on the fixed seat 3 relative to this reference. This reference can be a cylinder, a cone or a plane. The cooperation mode between this reference and the optical module main body can be the following ways:

[0173] The reference is a plane. The part of the optical module main body that matches this reference plane fits with this reference plane. At this time, the fixed seat 3 is also provided with a limiting member. The optical module main body has a component that matches this limiting member. The limiting member is used to limit the position of the optical module main body, so that the position of the optical module main body is limited to not be able to rotate or only be able to rotate around the optical axis of the optical module or translate along the optical axis of the optical module.

[0174] The reference is a cylinder or a cone. The cylindrical through hole or conical through hole of the optical module main body that matches this reference engages with this reference. After the cylindrical through hole or conical through hole of the optical module main body is matched with the reference, the optical module main body can only rotate around the axis of the cylinder or the cone or translate along the optical axis of the optical module while the incident pupil optical axis direction of the optical module main body remains unchanged.

[0175] In Figure 7 and Figure 8In the illustrated embodiment, the fixed base 3 has a first reference 31 and a second reference 32 serving as limit members, and a third reference 33 provided on the surface of the fixed base 3. For example, the first reference 31 and the second reference 32 are respectively provided on two spaced apart bosses formed on the surface of the fixed base 3. The first reference 31 and the second reference 32 are reference planes arranged at an angle, and both reference planes are perpendicular to the surface (the third reference 33) of the fixed base 3. This angle is 50° - 120°, preferably 86°, 88° or 90°. Then, the optical module body is placed within the space determined by the first reference 31 and the second reference 32 and is placed closely against the first reference 31 and the second reference 32. At this time, the position of the optical module body is uniquely determined.

[0176] Optionally, the fixed base 3 is further provided with a reference hole 34. When the optical module body is placed at a predetermined position on the fixed base 3, the entrance pupil optical axis of the optical module body is parallel to the axis of the reference hole 34 and the distance between the two is not greater than 5 m. Preferably, the entrance pupil optical axis of the optical module body coincides with the axis of the reference hole 34. The purpose of providing the reference hole 34 is to facilitate the calibration of the position of the camera 2 such that the optical axis of the camera 2 is parallel to the axis of the reference hole 34 and the distance between the two is not greater than 5 m. Preferably, the camera 2 takes a picture of the reference hole 34. If the obtained image of the reference hole 34 is a concentric circle, it indicates that the optical axis of the camera 2 coincides with the axis of the reference hole 34.

[0177] Furthermore, the fixed base 3 can be placed on a base 4 or any platform.

[0178] In another embodiment, a second adjustment mechanism 6 is further included. The second adjustment mechanism 6 is connected to the camera 2 and can adjust the position of the camera 2 such that the optical axis of the camera 2 coincides with the axis of the reference hole 34.

[0179] Figure 2 is a schematic structural diagram of an embodiment of the optical module assembly and adjustment test device of the present invention, and is provided with:

[0180] A control module 10 for controlling the adjustment mechanism 1 carrying the display device to move along a set direction with a set step length or rotate along a set direction with a set angular step length;

[0181] An image acquisition module 20 for acquiring a test legend image obtained by imaging the test legend displayed on the display device by the camera 2 through the optical module;

[0182] A calculation module 30 for calculating clarity indexes, optical axis offset indexes, and distortion indexes characterizing image quality;

[0183] A judgment module 40 for judging whether the clarity index, optical axis offset index, or distortion index of the test legend image meets the design requirements;

[0184] A predetermined position determination module 50 is configured to select an image with the optimal index from the images in which the clarity index, the optical axis offset index, or the distortion index determined by the determination module 40 meets the design requirements, and use the position of the display device corresponding to this image as the predetermined position.

[0185] Among them, the adjustment mechanism 1 is electrically connected to the processor 5 and receives the control instructions sent by the control module 10 to adjust the position of the display device according to the control instructions;

[0186] The camera 2 is located on the optical axis of the optical module, is electrically connected to the processor 5, and is used to collect the image of the test legend displayed by the display device and transmit the image to the image acquisition module 20 of the processor 5;

[0187] The image acquisition module 20 is signal-connected to the calculation module 30, and sends the acquired test legend signal to the calculation module 30. The calculation module sends the acquired clarity index, optical axis offset index, or distortion index result to the judgment module 40;

[0188] The judgment module 40 is respectively signal-connected to the predetermined position determination module 50 and the control module 10, and the judgment module 40 sends the judgment result to the predetermined position determination module 50 or the control module 10;

[0189] The predetermined position determination module 50 obtains the predetermined position of the display device according to the acquired judgment result, and the control module 10 generates a control instruction according to the judgment result and transmits it to the adjustment mechanism 1 to adjust the position of the display device.

[0190] Further, the adjustment module 10 is specifically configured to control the adjustment mechanism 1 to move from one end of the installation area corresponding to the display device along a set direction with a set step length, or rotate clockwise or counterclockwise with a set angular step length on one side of the corresponding rotation area centered on the center (axial direction) of the display device.

[0191] Further, the calculation module 30 specifically includes:

[0192] A clarity index calculation module 31 is configured to calculate a clarity value representing the clarity of the test legend image according to the image clarity algorithm;

[0193] An optical axis offset index calculation module 32 is configured to calculate the offset between the central feature point of the test legend image and the central feature point of the original test legend according to formula (1) to represent the optical axis offset index;

[0194] A distortion index calculation module 33 is configured to calculate the trapezoidal distortion amount of the test legend image according to formula (2) to represent the distortion index of the optical module.

[0195] Further, the distortion index calculation module 33 is specifically configured to select the quadrilateral feature formed by the four outermost feature points at the four corners of the test legend (refer to Figure 4A-1 and Figure 4B ), and for each quadrilateral, calculate the horizontal distortion amount and the vertical distortion amount of the display device according to Equation (2).

[0196] Further, the judgment module 40 is specifically configured to use an image sharpness algorithm to calculate the sharpness values of the test image according to the rows and columns where the collected test legend images are located respectively. The images with the sharpness values of the edge rows and columns not less than a first preset value and the sharpness values of the central rows and columns not less than a second preset value meet the design requirements. Usually, the first preset value is less than the second preset value, and the specific values are set according to application requirements.

[0197] Further, the predetermined position determination module 50 is specifically configured to:

[0198] Select the position corresponding to the image with the maximum value within the range of sharpness values from 1 to 7 as the marked position;

[0199] Among the images with the sharpness values of the edge rows and columns not less than a first preset value and the sharpness values of the central rows and columns not less than a second preset value, select the position corresponding to the image with the maximum sharpness value of the central rows and columns as the marked position;

[0200] Among the images with the sharpness difference at the symmetric positions of the test legend image less than a preset value, select the position of the display device corresponding to the image with the minimum sharpness difference as the first predetermined position;

[0201] Among the test legend images with the optical axis offset amount index meeting the design requirements, select the position of the display device corresponding to the image with the minimum optical axis offset amount of the test legend image as the second predetermined position.

[0202] Select the position of the display device corresponding to the image with the minimum trapezoidal distortion amount and the magnification meeting the design requirements obtained in the length direction of the display device as the first position, select the position of the display device corresponding to the image with the minimum trapezoidal distortion amount and the magnification meeting the design requirements obtained in the width direction of the display device as the second position, compare the trapezoidal distortion amounts of the test legend images obtained at the first position and the second position, and select the position corresponding to the image with the minimum trapezoidal distortion amount and the magnification meeting the design requirements as the third predetermined position.

[0203] Further, the device further includes a predetermined position verification module 60, which is signal-connected to the predetermined position determination module 50 and the control module 10, and is specifically configured to verify whether the display device is located at the predetermined position obtained by the predetermined position determination module 50, and whether the clarity index, the optical axis offset index, and the distortion index of the test legend image collected by the camera 2 meet the design requirements; if all meet the design requirements, then this position is the final predetermined position of the display device; otherwise, re-determine the movement range before and / or after and / or left and right at this predetermined position, and send the re-determined range to the control module 10 to re-adjust the position of the display device.

[0204] Based on the above optical module assembly and adjustment test method and the assembly and adjustment test device, the present invention realizes accurately fixing the component to be assembled on the optical module main body, and ensuring that the imaging clarity, optical axis offset, and distortion index of the optical module meet the design requirements. The present invention has the following beneficial effects:

[0205] (a) The optical module assembly and adjustment test device of the present invention uses a camera to simulate the imaging effect of the human eye. The optical parameters of the camera 2 are close to the optical parameters of the human eye, ensuring that the imaging effect is consistent with the human eye imaging, and as much as possible ensuring that the imaging meets the requirements of human eye comfort;

[0206] (b) By real-time detecting the imaging indexes such as the clarity, optical axis offset, distortion amount, and magnification of the test legend image collected by the camera 2, and according to the obtained imaging indexes, the position of the display device is adjusted in real time by the adjustment mechanism 1 to compensate for the adverse effects on the imaging quality caused by the structural tolerances and assembly tolerances of other optical components of the optical module, ensuring good imaging quality, completing the test of the optical module while assembling, improving the product yield and the finished product assembly test efficiency, and ensuring the consistency of the optical module products;

[0207] The assembly and adjustment test device of the present invention is simple to operate, stable and reliable, has good consistency, and meets the mass production requirements.

[0208] Those skilled in the art should understand that these embodiments are only used to illustrate the present invention and do not limit the scope of the present invention. All equivalent variations and modifications made to the present invention belong to the disclosure content of the present invention.

Claims

1. An optical module assembly, adjustment and testing method, characterized in that Including the following steps: Step S1, placing the optical module body at a predetermined position; Step S2, placing the display device of the optical module at the initial position; Step S3, adjusting the display device to the target position; And Step S4, fixing the display device, wherein, Step S3 includes: Step S31: Controlling the first adjustment mechanism to adjust the position of the display device, the camera sequentially acquires images of the test legends displayed by the display device, calculates the imaging clarity index of the optical module to be assembled, and among the images of the test legends whose clarity index meets the design requirements, selects the position of the display device corresponding to the image with the optimal clarity value as the first predetermined position; Step S32: Calculating the optical axis offset index of the optical module when the display device is at the first predetermined position. If the optical axis offset index does not meet the design requirements, control the first adjustment structure to adjust the position of the display device until the optical axis offset index meets the design requirements, and select the adjusted position of the display device as the second predetermined position; and Step S33: Calculating the distortion index of the optical module when imaging at the first predetermined position, the distortion index includes the amount of distortion and the magnification. If the distortion index does not meet the design requirements, control the first adjustment mechanism to adjust the position of the display device, the camera sequentially acquires images of the test legends displayed by the display device, and among the images of the test legends whose distortion index meets the design requirements, selects the position corresponding to the image with the minimum amount of distortion and the magnification meeting the design requirements as the third predetermined position of the display device, In Step S3, first execute Step S31, then execute Step S32 and S33, and the order of Step S32 and S33 is not limited until the clarity index, the optical axis offset index, and the distortion index meet the design requirements, wherein, Step S33 includes: Selecting any quadrilateral feature in the test legend, obtaining the four vector side lengths of the corresponding quadrilateral of the image of the test legend, and the calculation formula of the amount of distortion is as shown in Formula 1): wherein, among the selected quadrilateral features, ab and cd are the vector lengths of the two vertical sides, and ac and bd are the vector lengths of the two horizontal sides; and / or Selecting the proportional relationship between the distances of any two points in the image of the test legend displayed by the display device and the distances of the corresponding two points in the test legend image, and processing to obtain the magnification.

2. The optical module assembly, adjustment and testing method according to claim 1, wherein Before Step S3, it further includes Step S5: Adjusting the camera to the camera predetermined position so that the optical axis of the camera is parallel to the optical axis of the optical module and the distance between the two is within 5 mm; Setting the camera parameters to simulate the human eye visual effect.

3. The optical module assembly and adjustment test method according to claim 2, characterized in that, The optical axis of the camera coincides with the optical axis of the optical module.

4. The optical module assembly, adjustment and testing method according to claim 2, wherein In Step S5, the setting of the camera parameters includes: Adjusting the focus distance of the camera to the target focus distance; Adjusting the aperture value of the camera so that the aperture value matches the entrance pupil size of the human eye, and adjusting the entrance pupil position of the camera to match the exit pupil position of the optical module.

5. The optical module assembly and adjustment test method according to claim 2, characterized in that In Step S5, the position of the camera is calibrated through the reference holes provided on the fixed seat, and Step 5 includes the following steps: The camera takes an image of the reference hole, and adjusts the position of the camera until the image of the reference hole is a concentric circle, and at this time the camera is at the camera predetermined position.

6. The optical module assembly and adjustment testing method according to claim 1, characterized in that, In step S31, determining the first predetermined position of the display device specifically includes the following steps: Step S311, the first adjustment mechanism drives the display device to move within the movement range along the normal direction of the display plane of the display device at a set step size; Step S312, the camera sequentially acquires images of the test legends displayed by the display device imaged by the optical module at each position passed through, and records the position corresponding to the image at the same time; Step S313, calculating the clarity index of each acquired image of the test legend, and determining the movement position corresponding to the optimal clarity index as the marked position; Step S314, moving the display device to the marked position, setting the length direction of the display area of the display device as the X-axis and the width direction of the display area as the Y-axis; the first adjustment mechanism drives the display device to rotate at a set angular step along the X-axis and the Y-axis within a preset range, and then repeats steps S312 and S313, and determines the movement position corresponding to the optimal clarity index as the first predetermined position.

7. The optical module assembly, adjustment and testing method according to claim 6, wherein In step S313, obtaining the marked position specifically includes: Calculating the clarity values of the rows and columns of the acquired images of the test legends respectively, and among the images where the clarity values of the edge rows and columns and the center rows and columns all meet the preset range, selecting the position corresponding to the image with the largest clarity value of the center rows and columns as the marked position.

8. The optical module assembly and adjustment test method according to claim 6, characterized in that In step S312, the recording of the position corresponding to the image is achieved through the following steps: Automatically recorded by a processor, or manually recorded by the scale set on the first adjustment mechanism.

9. The optical module assembly, adjustment and testing method according to claim 1, wherein In step S32, the arithmetic formula for calculating the optical axis offset of the optical module is shown in formula (2):

10. The optical module assembly and adjustment test method according to claim 9, wherein In step S32, according to formula (2), calculating the optical axis offset index of the optical module when the display device is at the first predetermined position. If the optical axis offset index does not meet the design requirements, the steps for adjusting the position of the display device include: Adjusting the display device to the second preset position that meets the design requirements according to the obtained x offset and y offset.

11. The optical module assembly, adjustment and testing method according to claim 10, characterized in that, The design requirement is that both the x offset and the y offset are within ±30 pixels.

12. The optical module assembly and adjustment testing method according to claim 10, characterized in that The design requirement is that both the x offset and the y offset are within ±10 pixels.

13. The optical module assembly, adjustment and testing method according to claim 1, wherein In step S33, obtaining the third predetermined position of the display device specifically includes the following steps: Step 331, the first adjustment mechanism drives the display device to move along the length direction of the display device at a set step size, and the camera acquires the images of the test legends displayed by the display device imaged by the optical module during assembly; calculating the distortion index of each acquired image of the test legend, and among the test legend images that meet the design requirements of the distortion index, selecting the movement position corresponding to the test legend image with the smallest distortion amount and the magnification meeting the design requirements as the first position of the display device; Step S332: The first adjustment mechanism drives the display device to move along the width direction of the display device in a set step, and the camera captures the image of the test legend displayed on the display device after imaging by the optical module in the assembly; calculate the distortion index of each captured test legend image, and select the movement position corresponding to the test legend image with the smallest distortion amount and magnification meeting the design requirements among the test legend images that meet the design requirements of the distortion index as the second position of the display device; Step S333: Compare the distortion indexes of the test legend images obtained by the display device at the first position and the second position, and select the position corresponding to the position of the test legend image with the smallest distortion amount and magnification meeting the design requirements as the third predetermined position.

14. The optical module assembly and adjustment test method according to claim 1, characterized in that, The test legend is a preset legend, and the preset legend is a graphic pattern formed by several rows and columns of solid circles, or a grid formed by line pairs, or horizontal and vertical lines, or a combination of a solid circle and a line pair grid, or a checkerboard or a two-dimensional code.

15. An optical module assembly and adjustment test device for performing the steps in the optical module assembly and adjustment test method according to any one of claims 1-14, characterized in that, It includes a fixed seat and a camera, and the fixed seat has at least one reference for defining the position of the entrance pupil optical axis of the optical module body.

16. The device according to claim 15, wherein The reference includes a cylinder or a cone, and a cylindrical through hole or a conical through hole matching the reference is provided on the optical module body.

17. The device according to claim 15, characterized in that, The reference is a plane, and the part of the optical module body that matches the reference plane fits with the reference plane; The fixed seat is also provided with a limiting member for defining the position of the optical module body, and the limiting member cooperates with the component of the optical module body that matches the limiting member, so that the position of the optical module body is limited to not be able to rotate or only be able to rotate around the optical axis of the optical module or translate along the optical axis of the optical module.

18. The device according to claim 17, characterized in that, The reference includes a first reference, a second reference serving as a limiting member, and a third reference provided on the surface of the fixed seat. The first reference and the second reference are reference planes arranged at an angle, and both reference planes are perpendicular to the third reference.

19. The device according to claim 18, characterized in that, The angle between the first reference and the second reference is 50° - 120°.

20. The device according to claim 19, wherein The angle between the first reference and the second reference is 86°, 88° or 90°.

21. The device according to claim 15, characterized in that, The fixed seat is also provided with a reference hole, and the axis of the reference hole is parallel to the entrance pupil optical axis of the optical module body and the distance between the two is not greater than 5 mm.

22. The device according to claim 21, characterized in that, The axis of the reference hole coincides with the entrance pupil optical axis of the optical module body.

23. The device according to claim 15, characterized in that, It also includes a first adjustment mechanism for adjusting the position of the display device. The first adjustment mechanism is provided with a clamping mechanism, and one end of the clamping mechanism is provided with a picking part, and the picking part is any one of a clamping jaw, a suction cup, and a magnet.

24. The device according to claim 23, characterized in that, It also includes a processor, and the data interfaces of the camera and the first adjustment mechanism are respectively connected to the processor.

25. The device according to claim 21, characterized in that, It also includes a second adjustment mechanism for adjusting the position of the camera, and the second adjustment mechanism is connected to the camera.

26. An optical module assembly and adjustment testing device for performing the steps in the optical module assembly and adjustment testing method according to any one of claims 1 to 14, characterized in that, It includes: A control module, which conducts data interaction with the first adjustment mechanism and is used to control the first adjustment mechanism to adjust the position of the display device; An image acquisition module, which conducts data interaction with the camera and is used to obtain the image of the test legend displayed by the display device captured by the camera; A calculation module, which is signal-connected to the image acquisition module and is used to calculate the clarity index, the optical axis offset index, and the distortion index characterizing the quality of the test legend image; A judgment module, signal-connected to the calculation module, for judging whether the clarity index, optical axis offset index or distortion index of the test legend image meets the design requirements; A predetermined position determination module, signal-connected to the judgment module, for selecting an image with the optimal index from the images whose clarity index, optical axis offset index or distortion index is judged by the judgment module to meet the design requirements, and taking the position of the display device corresponding to this image as the predetermined position; And A control module, signal-connected to the judgment module, generating a control instruction according to the obtained judgment result and transmitting it to the first adjustment mechanism to adjust the position of the display device.

27. The optical module assembly and adjustment testing device according to claim 26, wherein The calculation module includes: A clarity index calculation module for calculating a gradient algorithm value or a gray scale statistical value characterizing the clarity of the test legend image according to an image clarity algorithm; An optical axis offset index calculation module for calculating the offset between the central feature point of the test legend image and the central feature point of the original test legend according to Equation (2) to characterize the optical axis offset index; and A distortion index calculation module for calculating the distortion amount or magnification of the test legend image according to Equation (1) to characterize the distortion index of the optical module.

28. The optical module assembly and adjustment testing device according to claim 27, wherein Specifically, the distortion index calculation module is used for: Selecting the four outermost feature points at the four corners of the test legend, and for each square formed by the four feature points at each corner, calculating the horizontal distortion amount and the vertical distortion amount of the display device respectively according to Equation (1); Selecting the proportional relationship between the distance between any two points in the image of the test legend displayed by the display device and the distance between the two corresponding points in the test legend image, and processing to obtain the magnification.

29. The optical module assembly and adjustment testing device according to claim 26, wherein Specifically, the control module is used for controlling the first adjustment mechanism to move from one end of the installation area corresponding to the display device along a set direction with a set step length, or to rotate clockwise or counterclockwise with a set angular step length on one side of the set rotation area with the center of the display device as the axis.

30. The optical module assembly and adjustment test device according to claim 26, characterized in that Specifically, the predetermined position determination module is used for: Selecting the position corresponding to the test legend image with the maximum clarity value within a specific range as the marked position; or Among the images whose clarity values of the edge rows and columns and the center rows and columns meet the preset range, selecting the position corresponding to the image with the maximum clarity value of the center rows and columns as the marked position; Among the images whose clarity difference at the symmetric positions of the test legend image meets the preset range, selecting the position of the display device corresponding to the image with the minimum clarity difference as the first predetermined position; Among the test legend images whose optical axis offset index meets the design requirements, selecting the position of the display device corresponding to the image with the minimum optical axis offset of the test legend image as the second predetermined position; Selecting the position of the display device corresponding to the image with the minimum distortion amount and the magnification meeting the design requirements obtained from the test legend image in the length direction of the display device as the first position, selecting the position of the display device corresponding to the image with the minimum distortion amount and the magnification meeting the design requirements obtained from the test legend image in the width direction of the display device as the second position, comparing the distortions of the test legend images obtained at the first position and the second position, and selecting the position corresponding to the image with the minimum distortion amount and the magnification meeting the design requirements as the third predetermined position.

31. The optical module assembly and adjustment testing device according to claim 26, characterized in that, It further includes a predetermined position verification module, which is signal-connected to the predetermined position determination module and the control module, and is specifically configured to: verify whether the display device is located at the predetermined position obtained by the predetermined position determination module, and whether the clarity index, the optical axis offset index, and the distortion index of the test legend image collected by the camera meet the design requirements; if all meet the design requirements, then this position is the final predetermined position of the display device; otherwise, re-determine the movement range before and / or after and / or left and right at this predetermined position, and send the re-determined range to the control module to re-adjust the position of the display device.

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