Planar Illumination Wiring on Opposite Substrate Surface
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Solution Overview
Problem
In planar illumination apparatuses, series wiring on flexible printed circuits (FPCs) faces challenges with stress concentration and disconnection due to narrow wiring widths and close LED spacing, making it difficult to arrange a cover layer and increasing the risk of solder flow onto the wiring, leading to potential disconnections.
Innovation Solution
The planar illumination apparatus features series wiring formed on the opposite surface of the substrate instead of the mounting surface, allowing for easier cover layer arrangement and reducing stress concentration by eliminating the need for soldering, thus preventing disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If series wiring is formed on the mounting surface of the FPC, then the wiring can be electrically connected with the LEDs, but the cover lay cannot be properly arranged and stress concentration occurs leading to disconnection
Solution Approach 1:
The series wiring is moved from the mounting surface (one dimension) to the opposite surface of the FPC (another dimension). This spatial relocation allows the cover lay to be properly arranged on the mounting surface without interfering with the wiring, while the wiring on the opposite surface remains electrically connected to the LEDs through appropriate connection structures.
2Volume of moving object
If the distance between adjacent LEDs becomes small, then the planar illumination apparatus can be miniaturized, but the series wiring becomes narrow and solder stress concentration increases
Solution Approach 1:
By relocating the series wiring to the opposite surface of the FPC, the wiring is no longer constrained by the narrow spacing between adjacent LEDs on the mounting surface. This allows the wiring to maintain sufficient width and strength even when the apparatus is miniaturized, as the wiring can be routed on the opposite surface where space constraints are different.
3Volume of moving object
If the wiring width is reduced for miniaturization, then the apparatus size decreases, but the wiring becomes more susceptible to stress and disconnection
Solution Approach 1:
The wiring is positioned on the opposite surface of the FPC, which provides a different spatial configuration that allows for adequate wiring width even in miniaturized devices. This separation from the LED mounting surface enables the wiring to maintain sufficient dimensions for mechanical strength while the overall apparatus remains compact.
Data Source
AI summary
A planar illumination apparatus according to an embodiment includes a light guide plate that outputs light entered into the light guide plate through a side face of the light guide plate, a plurality of light sources that are arranged on the side face side, and emit light to be entered into the side face, a substrate having a mounting surface where the light sources are mounted, and first wiring that is formed on an opposite surface opposite to the mounting surface of the substrate, and connects serially the light sources with each other.