Endoscope Electromagnetic Shield Wiring Pattern
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Solution Overview
Problem
Conventional methods for extracting electrodes from endoscope image sensors, such as wire bonding and TAB, face issues like package enlargement and reduced bending resistance due to narrow pitch arrangements.
Innovation Solution
An endoscope design featuring an objective lens, image sensor, drive circuit substrate, and an electromagnetic shield with a three-dimensional wiring pattern on its inner surface, allowing electrical connection between the image sensor and drive circuit without wire bonding or TAB, and using a cylindrical shield with a structure between the image sensor and lens for light entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to extract electrodes from the image sensor, then electrical connection is achieved, but the package size increases due to the necessity of providing a separate bonding pad around the chip
Solution Approach 1:
The electromagnetic shield and wiring pattern are merged into a single integrated structure. The shield simultaneously provides electromagnetic shielding and serves as the wiring substrate, eliminating the need for separate bonding pads and wire bonding processes. This integration reduces the overall package size while maintaining reliable electrical connections between the image sensor and external circuits.
Solution Approach 2:
The electromagnetic shield performs multiple functions: it provides electromagnetic shielding for the image sensor and simultaneously serves as a wiring substrate through the integrated wiring pattern. This multi-functional design eliminates the need for separate bonding pad structures, thereby reducing package size while ensuring reliable electrical connection.
2Volume of moving object
If TAB method is used to extract wires with narrow pitch arrangement, then package size is reduced, but bending resistance deteriorates
Solution Approach 1:
The wiring pattern is formed as a thin film structure on the inner peripheral surface of the cylindrical electromagnetic shield. This thin film wiring maintains flexibility and bending resistance while achieving narrow pitch arrangement for compact packaging. The film structure can accommodate bending stresses better than rigid TAB connections.
Solution Approach 2:
The wiring pattern transitions from a planar TAB structure to a three-dimensional configuration on the curved inner surface of the cylindrical shield. This dimensional change allows the wiring to follow the cylindrical geometry, providing both compact packaging and improved mechanical flexibility for bending applications.
3Reliability
If separate bonding pad is provided around the chip for wire bonding, then electrical connection is ensured, but the package size enlarges
Solution Approach 1:
The electromagnetic shield and wiring pattern are merged into a single integrated structure. The shield simultaneously provides electromagnetic shielding and serves as the wiring substrate, eliminating the need for separate bonding pads and wire bonding processes. This integration reduces the overall package size while maintaining reliable electrical connections between the image sensor and external circuits.
Solution Approach 2:
The electromagnetic shield performs multiple functions: it provides electromagnetic shielding for the image sensor and simultaneously serves as a wiring substrate through the integrated wiring pattern. This multi-functional design eliminates the need for separate bonding pad structures, thereby reducing package size while ensuring reliable electrical connection.
Data Source
AI summary
An endoscope includes an objective lens provided at a distal end portion of an insertion portion, an image sensor in which a light receiving area is formed on a surface facing the objective lens, and a drive circuit substrate that is disposed on a back side of the image sensor and includes a drive circuit to drive the image sensor, the endoscope further including an electromagnetic shield that houses the image sensor and the drive circuit substrate, in which the electromagnetic shield includes: a first shield member including a cylinder that covers a side portion of the image sensor, a structure that is disposed between the image sensor and the objective lens and that has an opening that allows entrance of light from the objective lens, and a wiring pattern that is formed on an inner peripheral surface of the cylinder and the structure.