Multi-layer Substrate Walls for Endoscope Imaging Unit Warping
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Solution Overview
Problem
Endoscope imaging units face challenges in miniaturization and reliability due to warping of multi-layer substrates, which affects the connection between semiconductor packages and electronic components, leading to instability in image sensor driving and increased impedance.
Innovation Solution
The implementation of walls on opposing sides of the multi-layer substrate's back surface to reduce warping, enhance connection reliability, and arrange electronic components in proximity to the image sensor for stable driving, while also optimizing cable and electrode arrangements to minimize thermal damage and improve yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the imaging unit is miniaturized by arranging components on a multi-layer substrate, then the diameter of the imaging unit is reduced, but the multi-layer substrate warps causing connection instability and increased impedance
Solution Approach 1:
The patent applies preliminary action by forming reinforcement structures (such as ground electrodes or metal layers) within the multi-layer substrate before mounting the image sensor and electronic components. These reinforcement structures are pre-positioned to counteract warping forces that will occur during operation, thereby maintaining substrate flatness and ensuring stable electrical connections throughout the device lifecycle
Solution Approach 2:
The patent employs parameter changes by modifying the physical and electrical parameters of the multi-layer substrate, including adjusting the thickness, material composition, and conductivity of various layers. By changing these parameters, the substrate's mechanical properties are optimized to resist warping while maintaining electrical performance, thus resolving the contradiction between miniaturization and connection reliability
2Adaptability or versatility
If electronic components are mounted on the back surface of the multi-layer substrate, then the layout flexibility is improved, but the substrate warping increases causing manufacturing difficulties
Solution Approach 1:
The patent applies preliminary action by incorporating reinforcement structures into the substrate design before component mounting. These structures are strategically positioned on the back surface to counteract the warping effects that would result from component weight and thermal expansion, thereby maintaining manufacturing precision while allowing flexible component layout
Solution Approach 2:
The patent employs asymmetry by strategically placing reinforcement structures and electronic components in asymmetric patterns on the back surface of the substrate. This asymmetric arrangement allows optimization of both layout flexibility and warping resistance, as the reinforcement can be concentrated in areas where it is most needed to counteract specific warping forces generated by component distribution
3Reliability
If signal cables are soldered to the circuit board, then electrical connection is established, but thermal damage to the image sensor occurs during soldering
Solution Approach 1:
The patent applies segmentation by dividing the circuit board into distinct functional layers, with the image sensor mounted on one layer and cable connection areas on separate layers. This segmentation allows the soldering process to be isolated from the image sensor, enabling reliable electrical connections to be made without exposing the sensor to damaging temperatures
Solution Approach 2:
The patent employs an intermediary approach by using the multi-layer substrate structure as a mediator between the signal cables and the image sensor. The substrate's multiple layers act as thermal barriers and signal transmission paths, allowing electrical connections to be established through the substrate without direct thermal contact between the soldering process and the image sensor, thus protecting the sensor from thermal damage
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 solution enables the miniaturization of endoscope imaging units with improved reliability, reduced impedance, and enhanced image quality by preventing substrate warping and stabilizing the image sensor's operation.
Implementation Method 1
an image sensor configured to generate an electric signal by receiving light incident from the optical system and by performing photoelectric conversion on the received light
Data Source
AI summary
An imaging unit includes: an optical system; a semiconductor package including an image sensor, and a connection electrode formed on a back surface; a cable; an electronic component; and a multi-layer substrate having a rectangular plate shape and including: a first electrode and a second electrode arranged side-by-side with each other on a front surface, the semiconductor package being mounted on the first electrode, and the cable being connected to the second electrode; and a third electrode on a back surface, the electronic component being mounted on the third electrode. The multi-layer substrate includes walls on at least two opposing sides of the back surface, and the semiconductor package is disposed such that a light receiving surface of the image sensor is arranged horizontally with respect to the multi-layer substrate.