Flexible Printed Circuit Board Inner Lead Connection for Endoscope Imaging Units
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing endoscope imaging units face challenges in maintaining reliable connections between the inner lead and electrode pads of solid state image sensors, leading to potential issues with signal transmission and increased size due to variations in layer thicknesses and unreliable bonding methods.
Innovation Solution
The imaging unit incorporates a flexible printed circuit board with an insulating base material, first and second surface-side wiring layers, and electrical insulating films, where the inner lead is connected to the electrode pad in a manner that minimizes variations in connection reliability and size, using a metallic reinforcing member and heat-shrinkable tube for stability, and employing a multi-layer substrate with via holes for electrical conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding methods are used to connect the inner lead to the electrode pad, then the connection can be established, but the connection reliability is poor and variations in layer thicknesses occur
Solution Approach 1:
The patent applies preliminary action by forming a recess in the insulating base material before mounting the solid state image sensor. This recess is designed to accommodate the sensor and establish a predetermined, consistent distance between the inner lead and the electrode pad, thereby pre-compensating for layer thickness variations and ensuring reliable connections before actual assembly occurs.
Solution Approach 2:
The patent changes the geometric parameter of the insulating base material by creating a recess with specific dimensions. This recess modifies the distance parameter between the inner lead and electrode pad, establishing a controlled and consistent spacing that compensates for manufacturing tolerances in layer thickness, thereby improving connection reliability.
2Reliability
If the imaging unit includes all necessary components for stable connection, then connection reliability improves, but the size of the imaging unit increases
Solution Approach 1:
The patent merges multiple functions into the insulating base material by integrating both the structural support function and the positioning function (through the recess) into a single component. This eliminates the need for separate positioning structures, thereby maintaining connection reliability while avoiding additional volume increase.
Solution Approach 2:
The patent employs a flexible printed circuit board (FPC) as the insulating base material, which provides both mechanical flexibility and structural integrity. This thin-film approach allows the material to accommodate connection requirements without adding significant bulk, thus improving reliability while maintaining a compact imaging unit size.
3Reliability
If the inner lead is bent along the side of the light-receiving surface, then connection can be established, but external static electricity interference occurs
Solution Approach 1:
The patent introduces a heat-shrinkable tube as an intermediary protective layer that covers the inner lead and its connection point to the electrode pad. This tube acts as a barrier against external static electricity, preventing harmful electrostatic discharge while allowing the inner lead to maintain its bent configuration for electrical connection.
Solution Approach 2:
The patent applies beforehand cushioning by pre-installing the heat-shrinkable tube over the inner lead before final assembly. This protective covering is in place before the imaging unit is subjected to external static electricity, providing advance protection against electrostatic damage to the sensitive electrical connections.
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 configuration enhances connection reliability, reduces the size of the imaging unit, and prevents external static electricity interference, ensuring stable signal transmission and a compact design.
Implementation Method 1
a solid state image sensor having an electrode pad and a light-receiving surface and configured to receive light and to perform photoelectric conversion on the received light to generate an electrical signal
Data Source
AI summary
An imaging unit includes: an image sensor having an electrode pad and a light-receiving surface; a flexible printed circuit board having an inner lead connected to the electrode pad and extending from the image sensor in a direction opposite to where the light-receiving surface is provided; and one or more electronic components mounted on a first surface of the flexible printed circuit board, the first surface being on a side where the image sensor is provided. The flexible printed circuit board includes: an insulating base material; a first wiring layer on the base material on a side of the first surface; a first film for insulating the first wiring layer; a second wiring layer on the base material on a side of a second surface opposite to the first surface; and a second film for insulating the second wiring layer. The inner lead extends from the first wiring layer.