Surface Mount Display Bezel Recess Design for Flat PCB
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Solution Overview
Problem
Heat staking in electronic display modules results in irregularities on the display circuit board, making it unsuitable for surface mounting and requiring costly and time-consuming rework to achieve a flat bottom surface, which compromises the holding strength of the mounting stakes.
Innovation Solution
Incorporating recesses in the display circuit board to contain the reformed plastic material from heat staking, allowing for a flat bottom surface without the need for extensive rework, using a thicker substrate to accommodate the volume of the heat stake lumps and providing various recess shapes such as stepped, V-shaped, and U-shaped designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat staking is used to attach mounting stakes from plastic components to the display circuit board, then the components are securely attached, but irregularities are created on the bottom surface of the circuit board
Solution Approach 1:
Recesses are pre-formed in the display circuit board at the locations where heat staking will occur. This preliminary action prepares the board to contain the reflowed plastic material, ensuring that the irregularities are captured before they can affect the bottom surface flatness.
Solution Approach 2:
The irregularities created by heat staking, which are normally harmful to surface mounting, are converted into a beneficial feature by containing them within recesses. The reflowed plastic material that would otherwise create surface irregularities is now contained within the recesses, allowing the bottom surface to remain flat while maintaining the holding strength of the stakes.
2Manufacturing precision
If rework is performed to remove irregularities from the bottom surface, then the display module becomes suitable for surface mounting, but the holding strength of the stakes is weakened and manufacturing time increases
Solution Approach 1:
Recesses are pre-formed in the display circuit board before heat staking occurs. This preliminary preparation eliminates the need for subsequent rework operations, as the irregularities are already contained within the recesses. This saves manufacturing time while maintaining surface flatness.
Solution Approach 2:
Instead of removing the irregularities through rework, the invention converts the harmful irregularities into a beneficial contained feature within recesses. This eliminates the need for time-consuming rework operations while preserving the holding strength of the stakes.
3Manufacturing precision
If rework is performed to remove irregularities from the bottom surface, then the display module becomes suitable for surface mounting, but the holding strength of the stakes is weakened
Solution Approach 1:
The invention converts the harmful irregularities into a beneficial feature by containing them within pre-formed recesses. This approach preserves the holding strength of the stakes, as the plastic material is contained rather than removed, while still achieving the required bottom surface flatness for surface mounting.
Solution Approach 2:
Recesses are pre-formed in the display circuit board before heat staking. This preliminary action ensures that the irregularities are contained within the recesses, preserving the holding strength of the stakes while achieving the necessary surface flatness without weakening the mounting structure.
4Manufacturing precision
If material is removed during rework to achieve flatness, then the bottom surface becomes suitable for surface mounting, but the holding strength of the stakes is considerably weakened
Solution Approach 1:
Instead of removing material through rework, the invention converts the harmful irregularities into a beneficial contained feature within recesses. This preserves the plastic material and maintains the holding strength of the stakes while achieving the required bottom surface flatness for surface mounting applications.
Solution Approach 2:
Recesses are pre-formed in the display circuit board before heat staking occurs. This preliminary preparation ensures that the reflowed plastic material is contained within the recesses, eliminating the need for material removal and preserving the holding strength of the mounting stakes.
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
Enables the display module to be used in a surface-mount environment without rework, reducing manufacturing time and cost while maintaining the holding strength of the mounting stakes.
Implementation Method 1
The process of heat staking involves passing a plastic member called a stake through a mounting hole in the display circuit board. The stake is heated, deforming the plastic material to cover part of the surrounding display circuit board, securing the stake in place.
Implementation Method 2
The stake is heated, deforming the plastic material to cover part of the surrounding display circuit board
Data Source
AI summary
Improved electronic display module for surface mount construction. Plastic components are heat-stake mounted to a printed circuit board substrate. Providing recesses for the reflowed plastic heat stakes reduces or eliminates rework required to provide flat surface needed for surface mounting.