Mobile phone screen assembly sealing optimization method and system

Abstract

The present application relates to mobile intelligent terminal display equipment manufacturing, industrial vision, computer vision, three-dimensional image detection, intelligent manufacturing equipment, industrial real-time control and light-cured precision dispensing technical field, especially to a kind of mobile phone screen assembly caulking optimization method and system. The depth data of annular assembly joint between the edge of mobile phone screen cover plate and the edge of mobile phone middle frame is obtained, the central path is established and the continuous caulking section is divided;In the geometric matching probe sub-section output equal volume probe glue, through different shading wetting time and non-contact air pressure pulse measurement, local infiltration response, local solidification state and interface bonding cutoff time are determined;Accordingly, the main caulking volume, the main caulking starting point, the main caulking direction and the pre-curing timing are determined, so that the main caulking glue is connected with the probe glue before the interface bonding cutoff time, and after the contour correction, the final solidification is carried out, the caulking contour consistency, interface bonding reliability and processing stability are improved.

Description

Technical Field

[0001] This invention relates to the fields of mobile intelligent terminal display device manufacturing, industrial vision, computer vision, 3D image detection, intelligent manufacturing equipment, industrial real-time control and photopolymerization precision dispensing technology, and in particular to a method and system for optimizing the seam of mobile phone screen assembly based on differential probe perturbation measurement and interface combination time-limit planning. Background Technology

[0002] In the assembly process of display devices such as mobile phones, it is usually necessary to fill the gap between the display screen and the mid-frame with sealant, so that the sealant serves the functions of connection, sealing, and appearance decoration. Existing Chinese patent document CN118173014A discloses a display device and its assembly process. It involves applying sealant at predetermined positions on the circumferential side panels of the mid-frame to fill the gap between the display screen and the mid-frame with low-modulus adhesive, and then removing any excess sealant to form part of the display device's surface. This document also points out that problems may occur during the sealant filling process, such as sealant overflow, unstable surface molding quality, and delamination at the interfaces of different sealants.

[0003] Furthermore, Chinese patent document CN107608101A discloses an online detection device for adhesive coating on liquid crystal panels. This device uses an alignment unit to determine the starting position and path of the adhesive coating, an adhesive coating unit to perform the coating, and a CCD camera to track and capture the coating position. Simultaneously, ultraviolet light is used to cure the adhesive. This solution enables online observation and automatic curing of the adhesive coating process, but it primarily relies on post-coating images to determine the coating effect.

[0004] However, the annular assembly seam between the edge of the mobile phone screen cover and the edge of the mobile phone frame is typically characterized by its narrow width, long path, significant changes in corner curvature, and difficulty in directly observing internal gaps. Furthermore, the wetting and spreading of the adhesive, its internal flow, and its curing state may vary at different locations. When processing using preset adhesive amounts, fixed dispensing paths, and fixed curing cycles, it is difficult to adapt to the actual conditions of different mobile phone screen assemblies and different sections of the annular assembly seam. This can easily lead to issues such as insufficient local filling, adhesive buildup, uneven exposed contours, or insufficient continuity of the adhesive interface formed in stages. Therefore, the existing technology still needs further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for optimizing the seam sealing of mobile phone screen assemblies, addressing the shortcomings of existing technologies. The technical problem it aims to solve is: how to accurately determine the required main seam volume for different continuous seam filling sections when there are local geometric differences in the annular assembly seam between the edge of the mobile phone screen cover and the edge of the mobile phone frame, and when the state of the photo-triggered curing adhesive changes during wetting, penetration, and pre-curing processes; and how to rationally coordinate the pre-curing sequence of the probe adhesive with the main seam filling path, so that the main seam filling adhesive can form a continuous adhesive with the probe adhesive within a suitable interface bonding time range, thereby improving the consistency of the seam sealing contour, the reliability of interface bonding, and the stability of automated processing of the mobile phone screen assembly.

[0006] The present invention specifically adopts the following solution: a method for optimizing the seam coverage of a mobile phone screen assembly, comprising the following steps: Gap modeling steps: Collect depth data of the annular assembly gap between the edge of the mobile phone screen cover and the edge of the mobile phone frame, establish the center path and divide the continuous filling section; Differential probe step: A light-triggered curing adhesive that does not undergo a primary curing reaction under light-shielding conditions is used. Two geometrically matched probe segments in the same continuous caulking section output probe adhesive of equal volume. The two probe adhesives are then subjected to the same light pulse for pre-curing after experiencing different light-shielding wetting times. Perturbation measurement steps: Before and after optical pulse pre-curing, apply the same non-contact air pressure pulse to the two probe colloids through the airflow port surrounding the dispensing nozzle, and obtain the surface displacement sequence and exposed volume after the air pressure pulse is applied and removed; Coupled inversion steps: Determine the local penetration response based on the difference in exposed volume loss corresponding to different shading and wetting durations; determine the local curing state based on the surface displacement recovery changes before and after light pulse pre-curing; and determine the interfacial binding cutoff time of the probe colloid. Time-limit planning steps: Determine the main filler volume based on the geometric data of the annular assembly seam, local penetration response, local curing state and target colloid profile; determine the main filler start point, main filler direction and pre-curing sequence based on the path time from the dispensing nozzle to the two probe segments and the interface binding cutoff time. The caulking and curing process is as follows: The main caulking is carried out according to the main caulking volume, the main caulking starting point, the main caulking direction and the pre-curing sequence, so that the main caulking colloid covers the edge area of ​​the two probe colloids before the interface bonding cutoff time. After contour correction, the final curing is performed.

[0007] Further, the differential probe step includes: setting multiple candidate probe segments along the continuous filler section, establishing a local cross-section perpendicular to the center path in each candidate probe segment; generating a gap geometric fingerprint based on the assembly seam width, assembly seam depth, first sidewall inclination angle, second sidewall inclination angle, assembly seam bottom curvature, and center path curvature corresponding to the local cross-section; comparing the normalized differences of the gap geometric fingerprints corresponding to any two candidate probe segments; and selecting the two candidate probe segments whose normalized differences are all within the corresponding matching threshold range and whose comprehensive normalized differences are the smallest as two geometric matching probe segments.

[0008] A further scheme, the perturbation measurement steps include: sequentially applying a first pressure pulse and a second pressure pulse to each probe colloid, wherein the pulse pressure of the second pressure pulse is greater than that of the first pressure pulse, and the pulse durations of the first and second pressure pulses are the same; acquiring the maximum surface displacement during the application of the first and second pressure pulses, the surface recovery time after removal, and the residual surface displacement after recovery; determining the flow response of the uncured colloid inside the probe colloid based on the maximum surface displacement increment of the second pressure pulse relative to the first pressure pulse; determining the constraint state of the surface cured structure of the probe colloid on the internal uncured colloid based on the residual surface displacement difference corresponding to the first and second pressure pulses; and determining the local curing state based on the flow response and the constraint state.

[0009] In a further proposed approach, the coupling inversion step would include: Cutoff calibration steps: Using multiple calibration colloids from the same batch as the photo-triggered curing adhesive, different cumulative light pulse energies are applied to each calibration colloid, and non-contact air pressure pulses are applied to each calibration colloid to obtain surface displacement recovery characteristics corresponding to different local curing states; after each calibration colloid has completed light pulse pre-curing, fresh colloid is covered at multiple waiting times, and the covered calibration colloids are subjected to final curing and the interfacial bonding strength is measured; the latest waiting time at which the interfacial bonding strength remains above the interfacial strength threshold is determined as the interfacial bonding cutoff time for the corresponding local curing state; a cutoff mapping relationship is established between surface displacement recovery characteristics, local curing state, and interfacial bonding cutoff time; In the coupling inversion step, the interfacial bonding cutoff time of the probe colloid is determined based on the surface displacement recovery characteristics and cutoff mapping relationship of the probe colloid. Specifically, the cutoff calibration step is performed before batch processing begins and is re-performed when changing the batch of phototriggered curing adhesive, changing the photocuring device, changing the ambient temperature range, or changing the material of the mobile phone frame. Multiple calibration colloids use the same batch of phototriggered curing adhesive as the actual grouting process and are output onto calibration substrates with the same or similar surface characteristics as the mobile phone screen cover material and mobile phone frame material. The initial volume, exposed contour, and substrate surface treatment conditions of each calibration colloid are kept consistent. Different cumulative light pulse energies can be obtained by changing the number of light pulses, the duration of a single light pulse, or the light intensity. To make the calibration results easily distinguishable, at least three cumulative light pulse energy levels can be set, corresponding to low, medium, and high pre-curing degrees, respectively. After each calibration colloid completes light pulse pre-curing, a non-contact air pressure pulse is applied under the same conditions as the actual perturbation measurement, and the maximum surface displacement, surface recovery time, residual surface displacement, and surface displacement recovery ratio are extracted. These parameters together constitute the surface displacement recovery characteristics. For multiple calibration colloids corresponding to the same cumulative light pulse energy, fresh colloids are applied at different waiting times. For example, fresh colloids can be applied at 0, 5, 10, 20, 30, and 40 seconds after pre-curing. When applying fresh colloids, the coverage width, thickness, and overlap area should be within the same range. The applied calibration colloids undergo the same final curing. After final curing and reaching the material's specified post-curing time, the interfacial bonding strength is measured by tensile, shear, peel, or other tests suitable for the colloid structure. At least multiple parallel samples are set for each waiting time, and the average value of the parallel sample measurements is used as the interfacial bonding strength at the corresponding waiting time. The interfacial strength threshold can be determined based on the reference strength of a complete, continuous colloid. For example, the strength of a reference sample formed from fresh colloid in one step and fully cured without pre-curing waiting is used as the reference interfacial strength, and 70% to 90% of the reference interfacial strength is set as the interfacial strength threshold. For the same local curing state, the latest waiting time in which the interfacial bonding strength remains above the interfacial strength threshold is determined as the interfacial bonding cutoff time. If two adjacent test times are above and below the interface strength threshold, respectively, the test can be repeated by adding an intermediate waiting period, or the interface bonding cutoff time can be estimated by interpolation. The cutoff mapping relationship should at least include the correspondence between surface displacement recovery characteristics, local curing state, and interface bonding cutoff time. During formal processing, the controller compares the measured surface displacement recovery characteristics of the probe colloid with the calibration characteristics in the cutoff mapping relationship, and selects the local curing state and interface bonding cutoff time corresponding to the calibration characteristics with the smallest difference.When the measured surface displacement recovery characteristics exceed the coverage of all calibration characteristics, the controller should not directly extrapolate the interface bonding cutoff time. Instead, it should reduce the accumulated optical pulse energy, re-execute the perturbation measurement, or re-calibrate the cutoff to avoid misestimating the interface bonding capability.

[0010] A further proposed solution includes the following time-limit planning steps: generating multiple candidate caulking paths that use different path positions as the main caulking starting points and extend along different circumferential directions; determining the expected arrival time of the dispensing nozzle along each candidate caulking path to each probe segment based on the current position of the dispensing nozzle, the candidate caulking paths, the dispensing nozzle's moving speed, and the positions of each probe segment; determining the interface arrival margin by the time difference between the probe adhesive interface and the corresponding expected arrival time; selecting the candidate caulking path from all candidate caulking paths where all interface arrival margins are positive and the minimum interface arrival margin is the largest; determining the starting point and circumferential direction corresponding to the selected candidate caulking path as the main caulking starting point and main caulking direction, respectively; when no candidate caulking path exists where all interface arrival margins are positive, reducing the cumulative optical pulse energy of the optical pulse pre-curing and re-executing the perturbation measurement and time-limit planning steps. Specifically, the candidate caulking path is jointly determined by the main caulking starting point and the main caulking direction. The main caulking starting point can be selected from multiple permissible starting points of the annular assembly joint, and the main caulking direction includes clockwise and counterclockwise directions. For each permissible starting point, clockwise and counterclockwise candidate caulking paths are generated. Permissible starting points should avoid camera openings, earpiece openings, locations of structural abrupt changes, locations with abnormal assembly seam widths, and locations unsuitable for forming start and end joints. Permissible starting points should also ensure that the dispensing nozzle can enter the annular assembly seam at a stable speed. The estimated arrival time is calculated from the moment the probe colloid completes photopulse pre-curing or from a unified time-limit planning reference time. The estimated arrival time includes the controller calculation time, the time for the dispensing nozzle to move from its current position to the main caulking starting point, the path movement time from the main caulking starting point to the corresponding probe segment, and the additional time due to corner deceleration. The dispensing nozzle movement speed does not necessarily need to remain constant along the entire candidate caulking path. The controller can set different movement speeds based on the curvature of continuous caulking segments and the geometry of the assembly seam, and obtain the path duration by accumulating the ratio of the length of each path segment to the corresponding movement speed. The interface arrival margin is the time difference between the interface binding cutoff time and the estimated arrival time. A margin of arrival greater than 0 indicates that the dispensing nozzle is expected to reach the corresponding probe segment before the probe colloid loses its qualified interfacial bonding ability; a margin of arrival less than or equal to 0 indicates that the corresponding candidate caulking path does not meet the time limit requirement. Each candidate caulking path has two margins of arrival, corresponding to two probe segments respectively. The controller takes the smaller of the two margins of arrival as the minimum margin of arrival for the corresponding candidate caulking path, and then selects the candidate caulking path with the largest minimum margin of arrival. This selection method ensures that the probe colloid with the more unfavorable time condition has the largest possible safety margin. When multiple candidate caulking paths have the same or similar minimum margins of arrival, the candidate caulking path with a shorter total path length, fewer nozzle turning times, or easier-to-shape start and end joint positions can be further selected.If no candidate caulking path exists where all interfaces reach a positive margin, the controller reduces the cumulative light pulse energy, causing the probe colloid to be in a locally cured state with a lower degree of pre-curing and a later interface bonding cutoff time. After reducing the cumulative light pulse energy, perturbation measurement needs to be performed again to redetermine the local curing state and interface bonding cutoff time based on the new surface displacement recovery characteristics. If no candidate caulking path that meets the conditions still does not exist after reducing the cumulative light pulse energy, the dispensing nozzle's movement speed within the allowable range can be increased, unnecessary pauses reduced, the main caulking start point candidate set changed, or two probe segments reselected.

[0011] A further embodiment of the filler curing step includes: determining the uncured core extension range in the probe colloid edge region based on the maximum surface displacement increment and residual surface displacement difference of the second pressure pulse relative to the first pressure pulse; determining the target coverage width and bridging colloid volume between the main filler colloid and the probe colloid based on the uncured core extension range; when the dispensing nozzle reaches the probe segment, first dispensing the bridging colloid according to its volume, so that it covers the probe colloid edge region and contacts the uncured core, then continuing to dispense the main filler colloid corresponding to the continuous filler segment; finally curing the bridging colloid, probe colloid, and main filler colloid together to form a continuously cured colloid. Specifically, the uncured core refers to the colloid region located inside the surface cured structure after the probe colloid completes photopulse pre-curing and still possesses flowability and cross-linking reaction capability. The uncured core extension range includes the width of the uncured core extending along the probe colloid edge direction and the thickness extending along the depth direction. The controller determines the flowability of the internal colloid based on the maximum surface displacement increment of the second pressure pulse relative to the first pressure pulse, and judges the constraint capability of the surface-cured structure based on the residual surface displacement difference. A large maximum surface displacement increment and a small residual surface displacement difference indicate that the surface-cured structure can recover while the interior still possesses strong fluidity, and the uncured core typically extends to a position close to the edge of the probe colloid. The extension range of the uncured core is obtained through pre-made cross-sectional calibration samples. During calibration, dual-pressure pulse measurements are performed on the colloid at different cumulative light pulse energies, followed by slicing, microscopic observation, or other cross-sectional inspections to obtain the actual uncured core range. A correspondence is established between the dual-pressure pulse parameters and the actual uncured core range. During formal processing, it is not necessary to cut open the mobile phone screen assembly; the extension range of the uncured core can be obtained by calling the correspondence based on the dual-pressure pulse results. The target coverage width is the width by which the main sealant or bridging colloid covers the edge of the probe colloid along the probe segment path. The target coverage width should ensure that the covered colloid reaches the area where the uncured core is located, while avoiding excessive coverage that could lead to localized colloid accumulation on the probe segment. The bridging adhesive volume is determined based on the target coverage width, probe adhesive edge height, annular assembly seam width, and target bridging cross-sectional area. The bridging adhesive can be dispensed at a lower flow rate than the normal main caulking flow rate to avoid impacting the probe adhesive edge. When the dispensing nozzle reaches the probe segment, the bridging adhesive is dispensed first. The bridging adhesive extends from one side of the main caulking adhesive to the edge area of ​​the probe adhesive, at least partially covering the extended range of the uncured core. After the bridging adhesive contacts the uncured core, the main caulking adhesive for the corresponding continuous caulking segment continues to be dispensed, ensuring no gaps between the bridging adhesive and the main caulking adhesive. The bridging adhesive, probe adhesive, and main caulking adhesive use the same phototriggered curing adhesive, or adhesives that have been verified to be compatible enough to cure together. During final curing, the bridging adhesive cross-links or interfacially bonds with both the probe adhesive and the main caulking adhesive, forming a continuously cured adhesive.After final curing, the presence of surface grooves at the bridging location can be determined by depth profile detection, and the internal continuity of the bridging location can be verified by sampling section detection or interface strength test.

[0012] A further proposed approach involves using two probe segments with corresponding geometric positions for adjacent mobile phone screen assemblies in the same batch, and exchanging the distribution relationship of the two light-shielding wetting durations between the two probe segments; based on the difference in exposed volume loss before and after the exchange, a first local penetration response and a second local penetration response are obtained respectively; when the difference between the first local penetration response and the second local penetration response is within the penetration consistency threshold range, the first local penetration response and the second local penetration response are fused; when the difference between the first local penetration response and the second local penetration response exceeds the penetration consistency threshold range, the corresponding continuous gap-filling segment is re-divided into multiple secondary gap-filling segments, and the differential probe step is re-executed for each secondary gap-filling segment.

[0013] A further scheme, contour correction includes: determining the volume of adhesive to be applied based on the volume difference between the pre-cured actual adhesive contour and the target adhesive contour; dividing the volume of adhesive to be applied into a first application volume and outputting the first application volume to the position where the contour is insufficient; measuring the exposed volume of adhesive corresponding to the first application volume after the application wetting time, and updating the local penetration response at the position where the contour is insufficient based on the volume difference between the first application volume and the exposed volume of adhesive; redetermining the remaining application volume based on the updated local penetration response; outputting the remaining application volume and re-detecting the actual adhesive contour, and performing final curing when the actual adhesive contour meets the target adhesive contour.

[0014] A mobile phone screen assembly seam optimization system includes a depth acquisition device, an adhesive dispensing device, an air pressure pulse device, a light curing device, and a controller; The depth acquisition device is used to acquire data on the depth of the annular assembly seam, the exposed volume of the probe adhesive, and the surface displacement sequence. The controller includes a gap modeling module for establishing a central path and dividing continuous gap-filling sections; a differential probe module for outputting equal-volume light-triggered curing adhesive at two geometrically matched probe segments, controlling different shading wetting durations and the same light pulse for pre-curing; a perturbation measurement module for controlling the air pressure pulse device to apply the same non-contact air pressure pulse before and after light pulse pre-curing; a coupling inversion module for determining the local penetration response based on the exposed volume loss difference, and determining the local curing state and interface bonding cutoff time based on the surface displacement recovery change; a time-limit planning module for determining the main gap-filling volume, main gap-filling start point, main gap-filling direction, and pre-curing sequence based on the local penetration response, local curing state, dispensing nozzle path duration, and interface bonding cutoff time; and a gap-filling curing module for controlling the dispensing device to cover the probe adhesive edge with the main gap-filling adhesive before the interface bonding cutoff time, and controlling the light curing device to perform final curing after contour correction.

[0015] A further embodiment includes an annular airflow port, a pulse control valve, an air pressure sensor, and a gas pressure stabilizing chamber arranged around the dispensing nozzle's dispensing channel. The central axis of the annular airflow port coincides with the central axis of the dispensing nozzle's dispensing channel. The annular airflow port is used to output an axisymmetric air pressure pulse to the probe adhesive surface when the dispensing nozzle stops dispensing adhesive. The air pressure sensor is used to detect the actual pulse pressure and actual pulse duration of the air pressure pulse. The perturbation measurement module is used to normalize the surface displacement sequence based on the actual pulse pressure and actual pulse duration, so that the surface displacement sequences before and after photopulse pre-curing have the same air pressure pulse reference.

[0016] In a further embodiment, the controller also includes a cutoff calibration module. The cutoff calibration module is used to associate and store the surface displacement recovery characteristics, local curing state, waiting time, and interface bonding strength after final curing corresponding to different cumulative light pulse energies, and to determine the latest waiting time at which the interface bonding strength is kept above the interface strength threshold as the interface bonding cutoff time. The coupling inversion module is used to match the surface displacement recovery characteristics of the probe colloid with the surface displacement recovery characteristics stored in the cutoff calibration module, and to output the corresponding local curing state and interface bonding cutoff time.

[0017] In a further embodiment, the time-limit planning module includes a candidate path generation unit, an interface arrival margin calculation unit, and a path selection unit. The candidate path generation unit generates multiple candidate caulking paths with different main caulking start points and directions. The interface arrival margin calculation unit determines the expected arrival time of the dispensing nozzle along each candidate caulking path to the probe segment, and determines the interface arrival margin between the interface bonding cutoff time and the expected arrival time. The path selection unit selects the candidate caulking path where all interface arrival margins are positive and the minimum interface arrival margin is the largest. The caulking curing module also outputs bridging adhesive covering the edge area of ​​the probe adhesive first, and then outputs the main caulking adhesive, when the dispensing nozzle reaches the probe segment.

[0018] The beneficial effects of this invention are: First, depth data of the annular assembly seam between the edge of the phone screen cover and the edge of the phone's mid-frame is acquired using a depth acquisition device. A central path is established, and continuous seam filling sections are defined. This allows subsequent processing to shift from relying solely on the standard design dimensions of the phone screen assembly to using the actual geometry of the assembly seam as the basis for seam filling control. This reduces the impact of assembly deviations in the phone screen cover, machining tolerances in the phone's mid-frame, and changes in corner curvature on the main seam volume and filling path.

[0019] By selecting two geometrically matched probe segments within the same continuous filler section and outputting equal volumes of probe colloid to both segments, allowing the two probe colloids to undergo different light-shielding wetting durations followed by the same light pulse pre-curing, it is possible to maintain consistent assembly joint geometry and initial adhesive volume while ensuring that the changes in the exposed volume of the two probe colloids primarily reflect the local penetration differences caused by the difference in wetting duration. Determining the local penetration response based on the difference in exposed volume loss corresponding to different light-shielding wetting durations reduces errors caused by estimating the internal flow of the colloid solely based on the material's rated viscosity or preset empirical coefficients, and allows the main filler volume to adapt to the actual assembly state of the current mobile phone screen assembly.

[0020] Before and after photopulse pre-curing, the same non-contact air pressure pulse is applied to the probe colloid through the airflow port surrounding the dispensing nozzle. The surface displacement sequence after the air pressure pulse is applied and removed is obtained. This allows for the acquisition of the maximum surface displacement, surface recovery time, and residual surface displacement of the probe colloid without using a physical probe to contact the colloid, without scratching the phone screen cover, and without excessively damaging the probe colloid contour. By comparing the changes in surface displacement recovery before and after pre-curing, the local curing state is determined, providing a measurable basis for judging the pre-curing state and reducing the deviation caused by estimating the degree of colloid curing solely based on a fixed irradiation time.

[0021] By pre-establishing a cutoff mapping relationship between surface displacement recovery characteristics, local curing state, and interface bonding cutoff time, the current non-contact perturbation response of the probe colloid can be converted into a time parameter that can be directly used for production control. The interface bonding cutoff time reflects the latest time at which the probe colloid, in its current local curing state, can still form a continuous interface with the subsequent main sealant that meets the interface strength requirements. This allows pre-curing to no longer solely focus on surface shaping of the colloid, but also consider the bonding ability between the probe colloid and the subsequent main sealant.

[0022] The time-limit planning step generates multiple candidate caulking paths with different main caulking start points and directions based on the path time from the dispensing nozzle to the two probe segments and the corresponding interface bonding deadline. It then selects the candidate caulking path where all interface arrival margins are positive and the minimum interface arrival margin is the largest. Therefore, the main caulking path is no longer simply determined by the shortest path or a fixed direction. Instead, the constraint of the colloid interface bonding capability changing over time is introduced into the path planning, allowing the dispensing nozzle to prioritize reaching the probe segments with smaller time margins. This reduces the risk that the probe colloid may fail to form a reliable continuous interface with the main caulking colloid due to excessive waiting time.

[0023] The main filler volume is determined by combining the geometric data of the annular assembly joint, local penetration response, local curing state, and target colloid profile. This approach simultaneously considers the actual space to be filled in the assembly joint, the expected penetration loss of the colloid into the joint, and the material state changes during pre-curing and final curing. Compared to using a fixed colloid dispensing rate, this method reduces the probability of insufficient filling in straight edge sections, colloid accumulation at corners, and inconsistent surface height after final curing.

[0024] When the dispensing nozzle reaches the probe segment, the target coverage width and bridging adhesive volume are first determined based on the extension range of the uncured core. This ensures the bridging adhesive covers the edge area of ​​the probe adhesive and contacts the uncured core before continuing to dispense the main sealant. This improves the material continuity between the probe adhesive, bridging adhesive, and main sealant. After all three are cured together, it reduces interface defects between the probe adhesive and the main sealant, such as superficial contact without sufficient internal bonding, thus improving the sealing continuity and interfacial bonding strength of the sealant.

[0025] During contour correction, the first filler volume is output, and the local penetration response is updated based on the filler exposure retention volume corresponding to the first filler volume. Then, the remaining filler volume is determined, which can use the actual filler response at the current contour deficiency location to correct the initial estimate. This tiered filler method can reduce local bulges and glue overflow caused by excessive filler in one go, and improve the consistency between the actual glue contour after contour correction and the target glue contour.

[0026] Through the collaborative work of the depth acquisition device, dispensing device, air pressure pulse device, light curing device, and various modules within the controller, a closed-loop processing link can be formed, from annular assembly seam modeling, probe colloid output, non-contact micro-perturbation measurement, local state inversion, main seam filling time limit planning, bridging seam filling, contour correction to final curing. This improves the automation level, parameter adaptation capability, appearance consistency, and finished product quality stability of the mobile phone screen assembly seam finishing process. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the signal flow of the execution steps of the mobile phone screen assembly seam optimization method of the present invention.

[0028] Figure 2 This is a schematic block diagram of the overall structure of the mobile phone screen assembly seam optimization system of the present invention.

[0029] Figure 3 This is a schematic diagram of the time limit planning of the two geometrically matched probe segments and the main caulking path in this invention.

[0030] Figure 4 This is a schematic diagram illustrating the cutoff mapping relationship between the surface displacement recovery characteristics, local solidification state, and interface bonding cutoff time of the present invention. Detailed Implementation

[0031] The following will combine Figures 1 to 4 The technical solutions in the embodiments of the present invention will be clearly and completely described. It should be noted that the following parameters are used to describe a specific configuration that can be implemented and do not constitute a limitation on the scope of protection. For different models of mobile phone screen assemblies, sealant, and dispensing devices, the corresponding parameters can be adjusted through calibration tests.

[0032] This embodiment uses a photo-triggered curing adhesive as the grout sealing material. Under light-shielded conditions, the photo-triggered curing adhesive does not undergo a primary curing reaction sufficient to affect the measurement of exposed volume within a preset light-shielding wetting time. It cures after being exposed to light of a preset wavelength. The photo-triggered curing adhesive can be a UV-curable acrylic adhesive, a UV-curable epoxy adhesive, or a composite colloid with corresponding curing properties.

[0033] The mobile phone screen assembly includes a screen cover and a mid-frame. After the screen cover is assembled to the mid-frame, an annular assembly seam is formed between the edge of the screen cover and the edge of the mid-frame. This annular assembly seam not only has an opening visible from the outside of the phone but may also have an invisible volume extending into the interior of the screen assembly. After photo-triggered curing adhesive enters the annular assembly seam, some of the adhesive remains near the seam opening, forming a visible seam outline, while another portion may continue to seep in along the bottom, sidewalls, or internal gaps communicating with the seam.

[0034] This implementation method forms two probe colloids of equal volume within the same actual annular assembly seam. Local penetration response is obtained by utilizing the different light-shielding wetting durations of the two probe colloids. Then, the local curing state is obtained by utilizing the non-contact air pressure pulse response before and after light pulse pre-curing, and the interface bonding cutoff time is determined from the local curing state. The grout optimization system determines the main grout start point, main grout direction, and pre-curing sequence based on the interface bonding cutoff time, ensuring that the two probe colloids connect with the main grout colloid before losing their interface bonding ability, and together form the final grout colloid.

[0035] The mobile phone screen assembly seam optimization system of this embodiment includes a depth acquisition device, an adhesive dispensing device, an air pressure pulse device, a light curing device, and a controller.

[0036] The depth acquisition device can employ a structured light 3D camera, a laser triangulation sensor, or a confocal displacement sensor. It is used to acquire depth data of the annular assembly seam, the exposed contours and volumes of the probe colloid and main sealant colloid, and the surface displacement sequence during the application of a pressure pulse. To simultaneously measure the gap and the minute deformation of the colloid, the lateral sampling interval of the depth acquisition device can be set from 5 micrometers to 25 micrometers, and the depth repeatability measurement error can be controlled within 2 micrometers to 10 micrometers.

[0037] The dispensing device includes a dispensing valve, a glue storage unit, a dispensing nozzle, and a motion actuator. The dispensing valve can be a screw valve, a piezoelectric jet valve, or a pneumatic precision dispensing valve. The outlet diameter of the dispensing nozzle can be set from 0.10 mm to 0.35 mm. The motion actuator moves the dispensing nozzle along the annular assembly seam and allows the nozzle to switch between the first probe segment, the second probe segment, and the main caulking path.

[0038] The pneumatic pulse device includes an annular airflow port surrounding the dispensing nozzle's dispensing channel, a pulse control valve, a pneumatic pressure sensor, and a gas pressure stabilizing chamber. The central axis of the annular airflow port coincides with the central axis of the dispensing nozzle's dispensing channel, ensuring that the output non-contact pneumatic pulse acts approximately perpendicularly onto the probe adhesive surface. When performing perturbation measurements, the dispensing nozzle stops dispensing and remains at a preset measurement height above the probe adhesive.

[0039] The photocuring device can use a 365 nm, 385 nm, or 395 nm ultraviolet light source. The photocuring device can output one or more light pulses, and the irradiation time, irradiation intensity, and cumulative light pulse energy of each light pulse are controlled by a controller.

[0040] The controller can be an industrial computer, a programmable logic controller, or an embedded controller with image processing capabilities. Internally, the controller includes a gap modeling module, a differential probe module, a perturbation measurement module, a coupling inversion module, a time-limited planning module, and a gap-filling curing module.

[0041] One possible implementation parameter is shown in Table 1.

[0042] Table 1. One possible implementation parameter

[0043] Before formal processing, the mobile phone screen assembly is fixed on the positioning platform, ensuring the outer surface of the screen cover is roughly horizontal. The depth acquisition device, dispensing device, pneumatic pulse device, and photopolymerization device all use the same workpiece coordinate system for coordinate unification. The workpiece coordinate system uses a positioning corner point of the positioning platform as the origin, the long side of the mobile phone screen assembly as the first coordinate axis, the short side as the second coordinate axis, and the direction perpendicular to the outer surface of the screen cover as the height direction.

[0044] like Figure 1 As shown, the method of this embodiment includes, in sequence, a gap modeling step, a differential probe step, a perturbation measurement step, a coupling inversion step, a time-limited planning step, and a gap filling and curing step.

[0045] First, the gap modeling process: The depth acquisition device scans along the edges of the phone screen cover and the phone frame to obtain depth data. The controller extracts the edges of the phone screen cover and the phone frame based on the depth data, and generates the center path of the annular assembly seam between the two edges.

[0046] The center path can be generated in the following way: at each sampling position of the annular assembly seam, determine the edge point of the mobile phone screen cover and the edge point of the mobile phone frame corresponding to the edge point of the mobile phone screen cover. Take the midpoint of the line connecting the two points as the center path point, and then connect each center path point in the circumferential order of the mobile phone screen assembly to form a closed center path.

[0047] The controller establishes multiple local cross-sections along the central path. Each local cross-section is approximately perpendicular to the local tangent of the central path. Based on the edges of the phone screen cover, the phone frame, and the bottom of the assembly seam in the local cross-sections, the assembly seam width, assembly seam depth, first sidewall inclination angle, second sidewall inclination angle, and assembly seam bottom curvature are obtained.

[0048] The controller divides continuous caulking sections based on changes in geometric parameters between adjacent sampling locations. Locations where there are significant changes in the joint width, joint depth, sidewall inclination angle, or center path curvature can be used as boundaries for continuous caulking sections. The geometric characteristics of the joint within each continuous caulking section are maintained within a preset fluctuation range, allowing the same continuous caulking section to employ the same or continuously varying local infiltration response.

[0049] Second, the differential probe procedure: The controller selects two geometrically matched probe segments within the same continuous caulking section. These two geometrically matched probe segments are referred to as the first probe segment and the second probe segment, respectively.

[0050] When selecting two geometrically matching probe segments, the assembly seam width, assembly seam depth, first sidewall inclination angle, second sidewall inclination angle, assembly seam bottom curvature, and center path curvature of each candidate probe segment are obtained. After normalizing each parameter, a gap geometric fingerprint is formed, and the comprehensive difference between any two candidate probe segments is calculated. The two candidate probe segments with the smallest comprehensive difference and no difference exceeding the corresponding matching threshold are selected as the first and second probe segments.

[0051] The first probe segment and the second probe segment have the same path length. The dispensing device outputs equal-volume probe adhesive to the first probe segment and the second probe segment, respectively. Equal-volume probe adhesive means that the commanded dispensing volume of the two probe adhesives is the same, and the actual volume difference is not greater than a preset volume error after calibration by the dispensing valve.

[0052] Both probe colloids remained in a light-shielded state after output. The first probe colloid underwent a first light-shielded wetting time, and the second probe colloid underwent a second light-shielded wetting time longer than the first. The light-shielding state ensured that the exposed volume change during the wetting waiting period primarily originated from the penetration of the colloid into the annular assembly seam, rather than from the photocuring reaction.

[0053] The depth acquisition device measures the initial exposed volume of the two probe colloids immediately after the probe colloids are output, and measures the exposed volume after wetting at the end of the corresponding light-shielding wetting time.

[0054] The local infiltration response can be determined by the following formula: ; Among them, local infiltration response This represents the exposed volume loss per unit path length and unit wetting time, and the initial exposed volume of the second probe colloid. This indicates the exposed volume of the second probe colloid immediately after output, and the exposed volume after the second probe colloid is wetted. This represents the exposed volume of the second probe colloid at the end of the second light-shielding wetting period, and the initial exposed volume of the first probe colloid. This represents the exposed volume of the first probe colloid immediately after output, and the exposed volume after the first probe colloid is wetted. The first probe colloid's exposed volume at the end of the first light-shielding wetting time, and the second light-shielding wetting time. This indicates the light-shielding wetting time of the second probe colloid, and the light-shielding wetting time of the first probe colloid. This indicates the light-shielding wetting time of the first probe colloid and the probe segment path length. This indicates the common path length of the first probe segment and the second probe segment.

[0055] By using the above differential calculation method, the influence of fixed volume deviation of the dispensing valve, initial differences in surface profile, and measurement zero-point deviation on local penetration response can be reduced.

[0056] After the two probe colloids have completed their light-shielding wetting process, the photocuring device applies the same light pulse to both probe colloids for pre-curing. Pre-curing with the same light pulse means that the two probe colloids receive the same wavelength, the same irradiation intensity, the same irradiation time, and the same cumulative light pulse energy.

[0057] Third, perturbation measurement steps: Perturbation measurements were performed before and after the optical pulse pre-curing. Dispensing stopped once the nozzle was above the probe colloid, and a non-contact pneumatic pulse device output non-contact pneumatic pulses to the probe colloid surface. A depth acquisition device continuously collected the probe colloid surface height, forming a surface displacement sequence.

[0058] In one embodiment, each probe colloid receives a first pressure pulse and a second pressure pulse in sequence. The pulse pressure of the second pressure pulse is greater than that of the first pressure pulse, and the durations of the two pressure pulses are the same.

[0059] For each pressure pulse, the controller extracts the maximum surface displacement, the surface recovery time after the pressure pulse is removed, and the residual surface displacement after the recovery is completed from the surface displacement sequence.

[0060] Maximum surface displacement reflects the deformability of the probe colloid when subjected to a pressure pulse; surface recovery time reflects the recovery speed under the combined action of internal flow and surface structure of the probe colloid; residual surface displacement reflects the permanent or semi-permanent deformation of the probe colloid that failed to recover after being subjected to a pressure pulse.

[0061] The surface displacement recovery ratio can be determined by the following formula: ; Among them, the surface displacement recovery ratio This indicates the proportion of the probe colloid displacement recovered after the gas pressure pulse is removed to the maximum surface displacement; the maximum surface displacement. This represents the maximum displacement of the probe colloidal surface relative to the initial surface during the gas pressure pulse, and the residual surface displacement. This indicates the remaining displacement of the probe colloid surface relative to the initial surface at the end of the preset recovery observation period.

[0062] Before photopulse pre-curing, the probe colloid has high fluidity, typically exhibiting a large maximum surface displacement, a slow recovery process, or significant residual surface displacement. After photopulse pre-curing, a certain cured structure forms on the surface of the probe colloid, resulting in changes in the maximum surface displacement, surface recovery time, and residual surface displacement.

[0063] The controller combines the maximum surface displacement before and after pre-curing, the surface recovery time, the residual surface displacement, and the surface displacement recovery ratio into a surface displacement recovery feature.

[0064] To reduce the impact of actual air pressure pulse pressure fluctuations on the measurement results, the air pressure sensor measures the actual pulse pressure and actual pulse duration for each air pressure pulse. The controller normalizes the surface displacement sequence according to the actual pulse pressure and actual pulse duration, so that the measurement results before and after pre-curing can be compared under the same air pressure pulse reference.

[0065] Fourth, the coupling inversion step: The controller first determines the local penetration response based on the difference in exposed volume loss of the two probe colloids under different shading and wetting durations; then, it determines the local curing state based on the changes in surface displacement recovery characteristics before and after pre-curing with the same light pulse. The local curing state can be represented by discrete or continuous states. In one embodiment, the local curing state is divided into a first local curing state, a second local curing state, and a third local curing state. The first local curing state indicates a low degree of pre-curing, where the colloid still has strong surface flowability and a long subsequent interface bonding time; the second local curing state indicates that the colloid has formed a surface structure that can maintain the contour, but still retains acceptable secondary bonding ability; the third local curing state indicates a relatively high degree of pre-curing, where the colloid has a stable contour, but the remaining time for reliable bonding with subsequent fresh colloids is short. The controller determines the interface bonding cutoff time of the corresponding probe colloid based on the surface displacement recovery characteristics and a pre-established cutoff mapping relationship. The interface bonding cutoff time refers to the latest time when, under the current local curing state, the probe colloid can still form a continuous interface with the subsequently covered fresh colloid that reaches the interface strength threshold.

[0066] The cutoff mapping relationship was obtained through independent calibration. During calibration, different cumulative light pulse energies were applied to multiple calibration colloids from the same batch, causing them to reach different local curing states. Non-contact air pressure pulse measurements were performed on each calibration colloid to obtain the corresponding surface displacement recovery characteristics. Subsequently, fresh colloid was applied to the surface of the calibration colloids at different waiting times after pre-curing, and final curing was performed. After final curing, tensile, shear, or peel tests were used to measure the interfacial bonding strength between the original colloid and the fresh colloid.

[0067] The latest waiting time when the interfacial bond strength is still above the interfacial strength threshold is determined as the interfacial bond cutoff time for the corresponding local curing state. The interfacial strength threshold can be set to 70% to 90% of the reference interfacial strength obtained by the co-curing of fresh colloids from the same batch.

[0068] Fifth, time-limited planning steps: The controller determines the main filler volume of each continuous filler section based on the geometric data of the annular assembly joint, the local penetration response, the local curing state, and the target colloid profile.

[0069] The target colloid cross-sectional area is determined by the target's visible width, target surface height, and the cross-sectional area to be filled inside the assembly joint. Considering local infiltration losses and expected curing volume changes, the main filler volume of the continuous filler section can be determined by the following formula: ; Among them, the Main caulking volume of continuous caulking sections Indicates the first The required output of the main sealant volume for each continuous sealant section, and the coordinates of the section's starting path. Indicates the first The starting position of each continuous joint caulking section, and the coordinates of the section's ending path. Indicates the first The termination position of a continuous caulking section, the target colloid cross-sectional area Represents path coordinates The target colloid cross-sectional area at the location, the first Local infiltration response in a continuous caulking section This represents the volume loss per unit path length and per unit wetting time of the corresponding continuous joint caulking section. Expected exposure time for each continuous caulking section This indicates the estimated time from output to profile stabilization of the main sealant, the [number]th [unit]. Path length of a continuous joint filling section Indicates the center path length of the corresponding continuous joint filling section, the first... The proportion of solidified volume change in a continuous joint filling section This indicates the expected percentage change in cured volume based on the local curing state and material calibration data.

[0070] The controller generates multiple candidate caulking paths with different main caulking start points and directions. For each candidate caulking path, the expected arrival time of the dispensing nozzle at the first and second probe segments is calculated based on the current position of the dispensing nozzle, the dispensing nozzle moving speed, the length of the candidate caulking path, and the positions of the two probe segments.

[0071] The margin for the interface is determined by the following formula: ; Among them, the interface reaches the margin. Indicates the dispensing nozzle along the first... The candidate caulking path reaches the first When the probe segment is reached, the remaining time before the corresponding probe colloid loses its qualified interfacial binding ability is considered. The probe colloidal interface is combined with the cutoff time. Indicates the first The latest moment when the probe colloid can still form a continuous interface with the fresh master sealant that reaches the interfacial strength threshold, the th The estimated arrival time of each candidate caulking path Indicates the dispensing nozzle along the first... The candidate caulking path reaches the first The estimated timing of each probe segment.

[0072] The controller excludes candidate caulking paths with an interface reach margin less than or equal to 0. Among the remaining candidate caulking paths, the candidate caulking path with the largest minimum interface reach margin is selected, and the starting point and circumferential direction of the selected path are respectively determined as the main caulking starting point and main caulking direction.

[0073] When all candidate caulking paths have an interface arrival margin less than or equal to 0, it indicates that the current pre-curing degree is too high or the main caulking cycle is too slow. The controller should reduce the cumulative light pulse energy, increase the dispensing nozzle movement speed within the allowable range, or start the main caulking earlier, and then re-execute the perturbation measurement step and the time limit planning step.

[0074] Sixth, the caulking and curing process: The dispensing device outputs the main caulking compound along the annular assembly seam according to the determined main caulking volume, main caulking starting point, and main caulking direction. The dispensing nozzle should be positioned before the interface bonding cutoff time of the corresponding probe compound when it reaches the first and second probe segments.

[0075] The main sealant covers the edge region of the probe sealant, creating a continuous sealant with overlapping portions between the main sealant and the probe sealant. Preferably, the controller can determine the extent of the uncured core extension in the edge region of the probe sealant based on the maximum surface displacement increment and the residual surface displacement difference measured by dual-pressure air pulses.

[0076] When the dispensing nozzle reaches the probe segment, bridging adhesive can be dispensed first, covering the edge of the probe adhesive and contacting the uncured core, before continuing to dispense the main sealant. The bridging adhesive, probe adhesive, and main sealant use photo-triggered curing adhesives from the same batch or compatible.

[0077] After the main caulking is completed, the depth acquisition device re-acquires the surface profile of the continuous colloid. The controller compares the actual colloid profile with the target colloid profile. For locations with insufficient profile, the volume of colloid to be filled is determined based on the volume difference.

[0078] To improve the accuracy of glue application, the first glue application volume can be output first. After the glue application wetting time, the exposed and retained volume of the first glue application volume can be measured. The local penetration response can be updated based on the difference between the first glue application volume and the exposed and retained volume of the first glue application volume. The remaining glue application volume can then be determined based on the updated local penetration response.

[0079] After contour correction, the photocuring device performs final curing on the probe colloid, bridging colloid, and main sealant colloid, creating a continuous curing interface between the colloids. After final curing, the colloid contour is captured again, and the visible width, surface height, edge continuity, surface pores, and local depressions are detected. The optimized results for the mobile phone screen assembly seam finishing are then output.

[0080] like Figure 2As shown, the depth acquisition device is located outside the controller and provides depth data to the gap modeling module, the perturbation measurement module, and the gap filling and curing module, respectively.

[0081] The gap modeling module receives depth data, generates a center path and continuous gap filling segments, and sends the continuous gap filling segment information to the differential probe module.

[0082] The differential probe module selects two geometrically matching probe segments based on the gap geometric fingerprint and outputs probe dispensing control commands to the dispensing device, so that the dispensing device outputs probe adhesive of equal volume in the two geometrically matching probe segments. Figure 2 The equal-volume probe colloid shown represents the probe colloid output control relationship between the differential probe module and the dispensing device.

[0083] The perturbation measurement module is communicatively connected to the pressure pulse device. The perturbation measurement module sends a control signal to the pressure pulse device to control the non-contact pressure pulses. The pressure pulse device outputs a first pressure pulse and a second pressure pulse based on the control signal. The depth acquisition device acquires surface displacement sequences during the application and removal of the pressure pulses and sends these sequences to the perturbation measurement module.

[0084] The coupled inversion module receives the exposed volume data from the differential probe module and the surface displacement recovery characteristics output by the perturbation measurement module to determine the local infiltration response, local curing state, and interface bonding cutoff time. The time-limit planning module receives the local infiltration response, local curing state, and interface bonding cutoff time, and, in conjunction with the center path and continuous filler sections, determines the main filler volume, main filler start point, main filler direction, and pre-curing sequence, and sends these control parameters to the filler curing module.

[0085] The joint caulking and curing module is communicatively connected to both the dispensing device and the UV curing device. The module sends control signals to the dispensing device corresponding to the main joint volume, main joint start point, and main joint direction, and sends pre-curing timing and final curing control signals to the UV curing device.

[0086] The photocuring unit outputs light pulses for pre-curing according to the pre-curing sequence, and performs final curing after contour correction is completed. The interface combined with the cutoff time is used to constrain the execution sequence of the filler curing module and the dispensing unit and the photocuring unit.

[0087] During the main grouting and contour correction process, the depth acquisition device continuously collects depth data and... Figure 2 The depth data detection feedback is sent to the joint filler and curing module. The joint filler and curing module determines whether the actual colloid contour meets the target colloid contour based on the detection feedback.

[0088] Figure 2The modules within the system form the main signal link in the following order: gap modeling module, differential probe module, perturbation measurement module, coupling inversion module, time-limited planning module, and gap filling and curing module. Externally, the depth acquisition device, dispensing device, air pressure pulse device, and photocuring device respectively complete the detection, dispensing, perturbation, and curing actions.

[0089] like Figure 3 As shown, the edge of the phone's mid-frame is located outside the edge of the phone's screen cover, and an annular assembly seam is formed between the edge of the phone's mid-frame and the edge of the phone's screen cover.

[0090] The first probe segment is located on one side of the annular assembly seam, and the second probe segment is located on the other side of the annular assembly seam. Each of the first and second probe segments contains a probe colloid. Each probe colloid has a corresponding interfacial bonding cutoff time.

[0091] Figure 3 The "Main Seam Start Point" indicates the position where the dispensing nozzle begins to continuously dispense the main seam sealant. The arrow along the circumferential assembly seam indicates the main seam direction. The main seam direction can be clockwise or counterclockwise. Figure 3 The path duration in the figure represents the time required for the dispensing nozzle to travel from the starting point of the main caulking joint to the first or second probe segment along the candidate caulking joint path. The path duration is not the same as the time corresponding to the straight-line distance, but is determined based on the actual length of the dispensing nozzle's movement path along the annular assembly joint, the allowable movement speed of each path segment, and the corner deceleration time.

[0092] For the same main caulking starting point, the path times to the two probe segments are typically different for clockwise and counterclockwise paths. For different main caulking starting points, the order in which the dispensing nozzle reaches the two probe segments may also differ. The controller calculates the interface arrival margins for each candidate caulking path. The interface arrival margin equals the interface bonding cutoff time minus the expected arrival time. For example, if the interface bonding cutoff time of the first probe colloid is earlier than that of the second probe colloid, the candidate caulking path that reaches the first probe segment earlier should be prioritized. However, path selection does not only consider the first probe segment; it must also ensure that the interface arrival margin of the second probe segment is also greater than 0. The controller ultimately selects the candidate caulking path with the largest minimum interface arrival margin. This selection method avoids a situation where a path, although reaching one probe segment earlier, causes the other probe segment to exceed the interface bonding cutoff time.

[0093] Figure 3 The first probe segment, the second probe segment, the probe colloid, the interface bonding cutoff time, the main filler start point, the main filler direction, and the path duration together constitute the input and output relationship of the time-limited planning steps.

[0094] like Figure 4As shown, the horizontal axis represents the waiting time, and the vertical axis represents the interface bonding strength. The three curves correspond to the first local curing state, the second local curing state, and the third local curing state, respectively.

[0095] For the same local curing state, as the waiting time increases, the active components on the probe colloid surface that can participate in subsequent interfacial bonding gradually decrease, and the viscosity, degree of cross-linking, or surface structure of the colloid change, ultimately leading to a decrease in the interfacial bonding strength after the probe colloid and the subsequent fresh colloid are finally cured.

[0096] Figure 4 The horizontal dashed line represents the interface strength threshold. The waiting time corresponding to the intersection of the curve for each local curing state and the interface strength threshold is the interface bonding cutoff time for the corresponding local curing state.

[0097] The first local curing state has a low degree of pre-curing and usually has a long interfacial bonding cutoff time; the second local curing state has a certain degree of contour stability and the interfacial bonding cutoff time is shorter than that of the first local curing state; the third local curing state has a relatively high degree of pre-curing and the shortest interfacial bonding cutoff time.

[0098] During actual calibration, multiple cumulative optical pulse energy levels can be set. For example, cumulative optical pulse energies of 8 mJ / cm², 16 mJ / cm², and 24 mJ / cm² can be set to create three different local curing states. For each local curing state, fresh colloid is applied at 0, 5, 10, 20, and 40 seconds after pre-curing, and the interfacial bonding strength is measured after final curing.

[0099] Table 2 provides an example of a cutoff mapping relationship. The values ​​in the table are for illustrative purposes only; the actual values ​​are determined by the specific colloidal material, ambient temperature, light energy, and the material of the phone's frame.

[0100] Table 2 Examples of Cut-off Mapping Relationships

[0101] Figure 4 The small diagram below illustrates the data flow of the cutoff mapping relationship. The controller first obtains the surface displacement recovery characteristics based on the surface displacement sequence before and after pre-curing, then determines the local curing state based on the surface displacement recovery characteristics, and finally determines the interface bonding cutoff time based on the pre-calibrated correspondence.

[0102] In actual operation, the controller does not need to re-perform the destructive interface strength test every time. The interface strength test is used for cutoff calibration before application or after changing material batches. During formal production, the controller obtains the surface displacement recovery characteristics through non-contact air pressure pulses, and then determines the interface bonding cutoff time by calling the cutoff mapping relationship.

[0103] To ensure the stable execution of this implementation method, the anomaly detection and handling methods shown in Table 3 can be adopted.

[0104] Table 3. Anomaly Detection and Handling Methods

[0105] The profile stability threshold can be determined by the maximum change in surface height between two consecutive depth measurements. For example, in two measurements with a 0.5-second interval, if the maximum change in surface height is less than 3 micrometers and this condition is met twice consecutively, the colloid can be considered to have reached a profile stable state.

[0106] Taking a mobile phone screen assembly with an average width of 0.22 mm and an average depth of 0.30 mm for annular assembly seams as an example, the mobile phone screen assembly is fixed to a positioning platform. A depth acquisition device scans the annular assembly seam at a path sampling interval of 10 micrometers. The controller extracts the edges of the mobile phone screen cover and the mobile phone frame, and generates a closed center path. Based on the changes in the width and depth of the assembly seam, the annular assembly seam is divided into 8 continuous filling sections. Within one of these continuous filling sections, the controller selects a first probe segment and a second probe segment, both 3 mm in length. The difference in assembly seam width between the two probe segments is less than 0.01 mm, the difference in assembly seam depth is less than 0.015 mm, and the difference in sidewall tilt angle is less than 3 degrees. A dispensing device outputs 0.15 microliters of probe adhesive to each of the two probe segments. The first probe adhesive is wetted in the dark for 2 seconds, and the second probe adhesive is wetted in the dark for 8 seconds. The depth acquisition device measures the initial exposed volume and the exposed volume after wetting of the two probe adhesives. After the exposed volume measurement is completed, the pressure pulse device first outputs a first pressure pulse of 1 kPa and lasts for 10 milliseconds to the two probe colloids, and then outputs a second pressure pulse of 2 kPa and lasts for 10 milliseconds. The depth acquisition device records the surface displacement sequence at a sampling frequency of 500 frames per second.

[0107] Subsequently, the photocuring device outputs the same light pulse with a cumulative energy of 16 millijoules per square centimeter to the two probe colloids for pre-curing, and then repeats the first and second pressure pulse measurements.

[0108] The controller determines the local penetration response based on the difference in exposed volume loss during the light-shielding wetting period, determines that the probe colloid is in the second local curing state based on the surface displacement recovery characteristics before and after pre-curing, and determines the corresponding interface binding cutoff time as 18 seconds through the cutoff mapping relationship.

[0109] The controller generates multiple candidate seam filling paths. The estimated arrival times of the first candidate seam filling path to the first probe segment and the second probe segment are 6 seconds and 14 seconds, respectively, with corresponding interface arrival margins of 12 seconds and 4 seconds. The corresponding interface arrival margins of the second candidate seam filling path are 7 seconds and 8 seconds, respectively. Although the first candidate seam filling path can reach the first probe segment earlier, its minimum interface arrival margin is 4 seconds, while the minimum interface arrival margin of the second candidate seam filling path is 7 seconds. Therefore, the controller selects the second candidate seam filling path.

[0110] The dispensing device outputs the main caulking adhesive according to the selected main caulking start point and main caulking direction, and sequentially covers the edge areas of the first probe adhesive and the second probe adhesive before the interface bonding cutoff time.

[0111] After the main caulking is completed, the depth acquisition device detects the continuous colloid profile. For areas with insufficient profile, the controller first outputs 40% of the volume to be filled with colloid, measures the exposed and retained volume of the colloid, updates the local penetration response, and then outputs the remaining volume of colloid.

[0112] After the contour correction is completed, the light curing device performs final curing. The final cured grout is continuously distributed along the annular assembly seam, and there are no identifiable interface breaks between the probe grout, bridging grout, and main grout. The actual grout contour is within the allowable error range of the target grout contour.

[0113] Through the above implementation method, the probe colloid does not need to be removed after calibration, but instead serves simultaneously as a measurement carrier for local penetration and curing states, as well as part of the final grout sealant. By using the local curing state to determine the interface bonding cutoff time, and by using the interface bonding cutoff time to constrain the starting point and direction of the main grout, it is possible to obtain local colloid state information while reducing interface delamination, cracks, or seal discontinuities between the probe colloid and the main grout sealant caused by excessively long waiting times.

Claims

1. A method for optimizing the seam coverage of a mobile phone screen assembly, characterized in that, Includes the following steps: Gap modeling steps: Collect depth data of the annular assembly gap between the edge of the mobile phone screen cover and the edge of the mobile phone frame, establish the center path and divide the continuous gap filling section; Differential probe step: A light-triggered curing adhesive that does not undergo a primary curing reaction under light-shielding conditions is used. Two geometrically matched probe segments in the same continuous caulking section output probe adhesive of equal volume. The two probe adhesives are then subjected to the same light pulse for pre-curing after experiencing different light-shielding wetting times. Perturbation measurement steps: Before and after optical pulse pre-curing, apply the same non-contact air pressure pulse to the two probe colloids through the airflow port surrounding the dispensing nozzle, and obtain the surface displacement sequence and exposed volume after the air pressure pulse is applied and removed; Coupled inversion steps: Determine the local penetration response based on the difference in exposed volume loss corresponding to different shading and wetting durations; determine the local curing state based on the surface displacement recovery changes before and after light pulse pre-curing; and determine the interfacial binding cutoff time of the probe colloid. Time-limit planning steps: Determine the main filler volume based on the geometric data of the annular assembly seam, local penetration response, local curing state and target colloid profile; determine the main filler start point, main filler direction and pre-curing sequence based on the path time from the dispensing nozzle to the two probe segments and the interface binding cutoff time. The caulking and curing process is as follows: The main caulking is carried out according to the main caulking volume, the main caulking starting point, the main caulking direction and the pre-curing sequence, so that the main caulking colloid covers the edge area of ​​the two probe colloids before the interface bonding cutoff time. After contour correction, the final curing is performed.

2. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 1, characterized in that, The differential probe procedure includes: Multiple candidate probe segments are set along the continuous caulking section, and a local cross-section perpendicular to the center path is established in each candidate probe segment. A gap geometric fingerprint is generated based on the assembly gap width, assembly gap depth, first sidewall inclination angle, second sidewall inclination angle, assembly gap bottom curvature, and center path curvature corresponding to the local cross-section. Compare the normalized differences of the gap geometric fingerprints corresponding to any two candidate probe segments; The two candidate probe segments with the smallest overall normalized difference that are all within the corresponding matching threshold range are selected as the two geometric matching probe segments.

3. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 2, characterized in that, The perturbation measurement steps include: A first pressure pulse and a second pressure pulse are applied sequentially to each probe colloid. The pulse pressure of the second pressure pulse is greater than that of the first pressure pulse, and the pulse durations of the first and second pressure pulses are the same. The maximum surface displacement during the first and second pressure pulses, the surface recovery time after removal, and the residual surface displacement after recovery are obtained respectively. The flow response of the uncured colloid inside the probe colloid is determined based on the maximum surface displacement increment of the second pressure pulse relative to the first pressure pulse. The constraint state of the probe colloid surface cured structure on the internal uncured colloid is determined based on the residual surface displacement difference corresponding to the first and second air pressure pulses. The local curing state is determined by combining the flow response and the constraint state.

4. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 3, characterized in that, The following steps are included before the coupling inversion step: Cut-off calibration steps: Using multiple calibration colloids from the same batch as the photo-triggered curing adhesive, apply different cumulative light pulse energies to the multiple calibration colloids respectively, and apply non-contact air pressure pulses to each calibration colloid to obtain the surface displacement recovery characteristics corresponding to different local curing states. After each calibration colloid completed photopulse pre-curing, fresh colloid was covered at several waiting times. The covered calibration colloids were then subjected to final curing and the interfacial bonding strength was measured. The latest waiting time for the interface bonding strength to remain above the interface strength threshold is determined as the interface bonding cutoff time for the corresponding local curing state. Establish a cutoff mapping relationship between surface displacement recovery characteristics, local solidification state, and interface bonding cutoff time; In the coupling inversion step, the interfacial binding cutoff time of the probe colloid is determined based on the surface displacement recovery characteristics and cutoff mapping relationship of the probe colloid.

5. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 4, characterized in that, Time-bound planning steps include: Multiple candidate grout paths are generated, each starting from a different path location and extending in different circumferential directions. Based on the current position of the dispensing nozzle, the candidate caulking path, the dispensing nozzle moving speed, and the position of each probe segment, determine the estimated arrival time of the dispensing nozzle along each candidate caulking path to each probe segment. The time difference between the interface cutoff time and the corresponding expected arrival time of the probe colloid is determined as the interface arrival margin. Select the candidate caulking path from all candidate caulking paths, where all interface reach margins are positive and the minimum interface reach margin is the largest. The starting point and circumferential direction corresponding to the selected candidate caulking path are respectively determined as the main caulking starting point and main caulking direction; When there are no candidate caulking paths where all interfaces have positive margins, reduce the cumulative optical pulse energy of the optical pulse pre-curing and re-execute the perturbation measurement step and the time limit planning step.

6. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 5, characterized in that, The grout curing process includes: The extent of the uncured core extension in the probe colloid edge region is determined based on the maximum surface displacement increment and residual surface displacement difference of the second pressure pulse relative to the first pressure pulse. The target coverage width and bridging colloid volume between the main sealant and the probe colloid are determined based on the extent of the uncured core extension. When the dispensing nozzle reaches the probe segment, it first outputs bridging adhesive according to the volume of bridging adhesive, so that the bridging adhesive covers the edge area of ​​the probe adhesive and contacts the uncured core, and then continues to output the main bridging adhesive for the corresponding continuous bridging segment. The bridging colloid, probe colloid, and main sealant are all subjected to final curing together, so that the bridging colloid, probe colloid, and main sealant form a continuously cured colloid.

7. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 6, characterized in that, Adjacent mobile phone screen assemblies in the same batch use two probe segments with corresponding geometric positions, and exchange the distribution relationship of two light-shielding wetting times between the two probe segments; Based on the difference in exposed volume loss before and after the exchange, the first local infiltration response and the second local infiltration response are obtained respectively. When the difference between the first local infiltration response and the second local infiltration response is within the infiltration consistency threshold range, the first local infiltration response and the second local infiltration response are fused. When the difference between the first local infiltration response and the second local infiltration response exceeds the infiltration consistency threshold, the corresponding continuous joint-filling section is re-divided into multiple secondary joint-filling sections, and the differential probe step is re-executed for each secondary joint-filling section.

8. The method for optimizing the seam coverage of a mobile phone screen assembly according to claim 7, characterized in that, Contour correction includes: The volume of adhesive to be added is determined based on the volume difference between the actual colloid profile after pre-curing and the target colloid profile. Divide the first glue filling volume from the volume to be glued, and output the first glue filling volume to the position where the contour is insufficient; After the glue wetting time, the exposed glue retention volume corresponding to the first glue volume is measured. The local penetration response at the insufficient contour location is updated based on the volume difference between the first glue volume and the exposed glue retention volume. The remaining filler volume was re-determined based on the updated local penetration response; After outputting the remaining adhesive volume, the actual adhesive profile is re-detected, and final curing is performed when the actual adhesive profile meets the target adhesive profile.

9. A mobile phone screen assembly seam optimization system, characterized in that, Includes a depth acquisition device, a dispensing device, a pneumatic pulse device, a photocuring device, and a controller; The depth acquisition device is used to acquire data on the depth of the annular assembly seam, the exposed volume of the probe adhesive, and the surface displacement sequence. The controller includes a gap modeling module, which is used to establish a central path and divide continuous gap filling sections; The differential probe module is used to output equal-volume light-triggered curing adhesive from two geometrically matched probe segments, controlling different shading wetting times and the same light pulse pre-curing; the perturbation measurement module is used to control the air pressure pulse device to apply the same non-contact air pressure pulse before and after light pulse pre-curing. The coupling inversion module is used to determine the local penetration response based on the difference in exposed volume loss, and to determine the local curing state and the interface bonding cutoff time based on the surface displacement recovery change; the time-limit planning module is used to determine the main caulking volume, main caulking start point, main caulking direction and pre-curing sequence based on the local penetration response, local curing state, dispensing nozzle path duration and interface bonding cutoff time. The caulking and curing module controls the dispensing device to cover the edge of the probe adhesive with the main caulking adhesive before the interface bonding cutoff time, and controls the photocuring device to perform final curing after contour correction.

10. The mobile phone screen assembly seam optimization system according to claim 9, characterized in that, The pneumatic pulse device includes an annular airflow port surrounding the dispensing channel of the dispensing nozzle, a pulse control valve, a pneumatic pressure sensor, and a gas pressure stabilizing chamber; The central axis of the annular airflow port coincides with the central axis of the dispensing channel of the dispensing nozzle. The annular airflow port is used to output an axisymmetric air pressure pulse to the probe adhesive surface when the dispensing nozzle stops dispensing adhesive. The barometric pressure sensor is used to detect the actual pulse pressure and the actual pulse duration of a barometric pressure pulse. The perturbation measurement module is used to normalize the surface displacement sequence based on the actual pulse pressure and actual pulse duration, so that the surface displacement sequences before and after photopulse pre-curing have the same air pressure pulse reference. The controller also includes a cutoff calibration module, which is used to associate and store the surface displacement recovery characteristics, local curing state, waiting time and final curing interface bonding strength corresponding to different cumulative light pulse energies, and to determine the latest waiting time when the interface bonding strength is kept above the interface strength threshold as the interface bonding cutoff time; the coupling inversion module is used to match the surface displacement recovery characteristics of the probe colloid with the surface displacement recovery characteristics stored in the cutoff calibration module, and output the corresponding local curing state and interface bonding cutoff time; The time-limit planning module includes a candidate path generation unit, an interface arrival margin calculation unit, and a path selection unit; The candidate path generation unit is used to generate multiple candidate grout paths with different main grout start points and main grout directions; The interface arrival margin calculation unit is used to determine the expected arrival time of the dispensing nozzle along each candidate caulking path to the probe segment, and to determine the interface arrival margin between the interface bonding cutoff time and the expected arrival time; the path selection unit is used to select the candidate caulking path where all interface arrival margins are positive and the minimum interface arrival margin is the largest; the caulking curing module is also used to first output the bridging adhesive covering the edge area of ​​the probe adhesive when the dispensing nozzle reaches the probe segment, and then output the main caulking adhesive.

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