Surface-Emitting Light Source via Dry Pressing
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Solution Overview
Problem
Existing surface-emitting light sources face reliability issues in connection due to the complexity of wet processes and unevenness in dry processes, leading to potential air gaps and reduced adhesion during the manufacturing of via-conductors.
Innovation Solution
A surface-emitting light source design featuring a wiring substrate with a covering layer defining openings smaller than the wiring pads, an adhesive layer, and electrically-conductive members supplied into vias, allowing for a reliable dry process connection by pressing and heating, which enhances bonding and reduces via-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroless or electrolytic copper plating is performed in via holes to dispose via-conductors, then via-conductors can be formed inside via-holes, but the plating is performed in a wet process so that large-scale devices may be used and manufacturing steps may be complicated
Solution Approach 1:
The patent replaces the wet chemical plating process with a mechanical pressing and heating process. The wiring substrate and light-emitting module are connected by applying pressure and heat, eliminating the need for electroless or electrolytic copper plating. This substitution simplifies the manufacturing process while maintaining connection reliability.
Solution Approach 2:
The patent changes the process parameters from wet chemical conditions to dry thermal-mechanical conditions. By controlling temperature and pressure parameters during pressing, the connection is formed without requiring complex plating chemistry, thus reducing manufacturing complexity while ensuring reliable electrical connection.
2Device complexity
If a dry-process technique is used to connect wiring board and light-emitting module by pressing while heating, then manufacturing steps are simplified, but connection reliability may be reduced due to unevenness and potential air gaps
Solution Approach 1:
The patent applies local quality by creating protrusions on the wiring substrate at specific via locations. These localized structural features ensure proper filling and contact at critical connection points, preventing air gaps and improving adhesion where it is most needed, thereby enhancing connection reliability without complicating the overall dry process.
Solution Approach 2:
The patent performs preliminary action by forming protrusions on the wiring substrate before the pressing operation. This pre-prepared structure ensures that when pressing and heating occur, the via-conductors are properly guided and contacted, preventing air gaps and ensuring reliable connection from the outset rather than relying solely on the pressing process itself.
3Reliability
If via-conductors are formed using wet process plating, then electrical connection is established, but adhesion unevenness and air gaps may occur reducing connection quality
Solution Approach 1:
The patent introduces protrusions at specific via locations to create localized regions of enhanced contact and adhesion. This local quality approach ensures that critical connection points have proper filling and contact, eliminating air gaps and improving adhesion uniformity where it matters most for electrical connection reliability.
Solution Approach 2:
The protrusions act as intermediaries between the wiring substrate and the via-conductors. These structural features facilitate proper material flow and contact during pressing, mediating the connection process to ensure uniform adhesion and eliminate air gaps, thereby improving manufacturing precision.
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
The solution increases the reliability of connections between the wiring substrate and light-emitting modules, reduces air gaps, and improves adhesion, resulting in a more stable and efficient surface-emitting light source.
Implementation Method 1
an adhesive layer between the plurality of light-emitting modules and the wiring substrate
Implementation Method 2
pressing and heating to obtain an electrically-conductive member and to bond the wiring substrate and the light-emitting modules through the adhesive layer
Implementation Method 3
pressing and heating to obtain an electrically-conductive member and to bond the wiring substrate and the light-emitting modules through the adhesive layer
Data Source
AI summary
A surface-emitting light source includes: light-emitting modules; a wiring substrate including a base member having a surface at a light-emitting modules side and a rear surface opposite to that, a wiring layer on the rear surface of the base member and including wiring pads being portions of the wiring layer, electrically-conductive members each supplied across corresponding two or more of a plurality of vias in each of the wiring pads, and a covering layer covering the wiring layer and defining openings in each of which a portion of a corresponding one of the wiring pads is exposed; and an adhesive layer between the light-emitting modules and the wiring substrate. Each light-emitting module has an array of light emitting devices. The covering layer defines the openings at locations corresponding to the wiring pads with an area dimension smaller than respective area dimensions of the wiring pads.