Flexible Sheet Adhesive Retention for Sensor Board Alignment
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Solution Overview
Problem
Existing methods for attaching a sensor board to an optics unit face challenges in keeping the UV-curable adhesive in place during alignment, leading to issues with proper curing and strength of the bond, especially when viscosity deviates or steps take longer than expected, and are not robust or cost-effective.
Innovation Solution
A method involving a flexible sheet with cuts or perforations across the mouth of the through-going hole on the sensor board, allowing the adhesive to be applied from the opposite side and ensuring it fills the space between the protruding structure and the hole, which is then cured, providing a robust and efficient bonding solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV-curable adhesive is applied to the interface between sensor board and optics unit, then the sensor board can be fixed after alignment, but the adhesive cannot be kept in place during the alignment process
Solution Approach 1:
The adhesive is applied in advance to the protruding pin before the sensor board is positioned, so that the adhesive is already in place and ready to bond when alignment is complete. This preliminary application ensures the adhesive remains in position throughout the alignment process without requiring tape or other retention methods.
2Reliability
If tape is applied to cover the mouth of through-going holes, then adhesive can be kept in place, but it becomes difficult to apply the exact amount of adhesive and may lead to overfilling
Solution Approach 1:
A flexible adhesive retention element in the form of an annular strip with radial cuts is placed over the hole mouth. This flexible film structure allows precise control of adhesive amount while maintaining retention, as the cuts enable the strip to conform to the pin and adhesive interface without requiring excessive material or complex positioning.
3Quantity of substance
If adhesive is overfilled in the cup, then the void is completely filled, but adhesive is pushed out into shadowed areas where it cannot be properly cured
Solution Approach 1:
The adhesive retention element acts as an intermediary barrier between the adhesive and the external environment. It allows the adhesive to fill the void completely while preventing excess adhesive from escaping into shadowed areas, ensuring all adhesive remains in cureable positions.
4Device complexity
If protruding pins are limited to extend within the material thickness of sensor board, then the structure is simple, but design freedom is restricted
Solution Approach 1:
The flexible adhesive retention element compensates for pins extending beyond the sensor board thickness. By providing a flexible barrier at the hole mouth, the system can accommodate pins of various lengths without requiring the pin to be precisely limited to the board thickness, thereby increasing design freedom while maintaining structural simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for precise alignment and robust bonding without overfilling adhesive, minimizing shadowed areas and ensuring proper curing, while being cost-effective and easy to integrate into existing assembly lines, offering design freedom and efficient use of materials.
Implementation Method 1
the UV-curable adhesive is subjected to UV-light and thereby cures
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A method of attaching a light source or sensor board arrangement (10) to a base unit (20), wherein the base unit (20) is provided with a protruding structure (21) and the light source or sensor board arrangement (10) is provided with a through-going hole (11), wherein the method comprises: providing a piece of a flexible sheet (30) on a first side (10a) of the light source or sensor board arrangement (10a) across a mouth (11a) of the through-going hole (11), the piece of flexible sheet (30) being provided with cuts or perforations (31a-g) dividing a part (30a) of the piece of flexible sheet (30) extending across the mouth (10a) into flaps (32a-f); applying a curable liquid adhesive (40) from a second side (10b); moving the light source or sensor board arrangement (10) relative to the base unit (20) such that the protruding structure (21) is inserted into the through-going hole (11) along a first direction (A) through the part (30a) of the piece of flexible sheet (30) such that free ends of the flaps (32a-f) are pushed in the first direction (A) into the through-going hole (11); aligning the light source or sensor board arrangement (10) relative to the base unit (20); and curing the curable liquid adhesive (40). An assembly comprising a light source or sensor board arrangement (10) attached to a base unit (20) in accordance with the method.