Optical Transmitter Wiring Board Alignment for Endoscope
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Solution Overview
Problem
The challenge in endoscope design is to achieve high optical coupling efficiency between the optical device and the optical fiber while maintaining a compact size, which requires precise positioning of the optical device and the optical fiber, especially when using high-pixel image pickup devices that increase signal transmission demands.
Innovation Solution
The optical transmitter design includes a wiring board with a flat plate-shaped wiring pattern sandwiched between insulating layers, an optical device mounted closer to the second main surface, and a holding member with a through hole for the optical fiber, ensuring the fiber's end surface contacts the wiring pattern and the external electrode is bonded to the lower surface, facilitating accurate positioning and high mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between the optical device and the optical fiber end surface is reduced to increase optical coupling efficiency, then the optical coupling efficiency is improved, but the positioning precision requirement becomes more stringent
Solution Approach 1:
The patent introduces a wiring board as an intermediary component between the optical device and the optical fiber. The wiring board includes a through-hole that receives the optical fiber and positioning protrusions that engage with recesses on the optical device, mediating the connection and providing mechanical stability while maintaining optical coupling efficiency
Solution Approach 2:
The patent implements preliminary positioning actions by providing positioning protrusions on the wiring board that fit into positioning recesses on the optical device before final assembly. This preliminary positioning ensures accurate alignment of the optical fiber with the light emitting portion, reducing the burden on final assembly operations
2Area of stationary object
If the outer diameter and length of the distal end portion are reduced to secure observation field of view, then the observation field of view is improved, but the positioning accuracy becomes more difficult to achieve
Solution Approach 1:
The patent transitions from two-dimensional positioning on a flat surface to three-dimensional positioning using protrusions and recesses that extend in multiple dimensions. The positioning protrusions on the wiring board engage with corresponding recesses on the optical device, providing stable positioning in the vertical dimension while maintaining compact lateral dimensions for improved field of view
Solution Approach 2:
The patent implements a nested structure where the optical fiber is inserted into a through-hole of the wiring board, which itself is positioned within the compact distal end portion housing. This nesting approach allows precise positioning of multiple components within a minimized outer diameter and length
Data Source
AI summary
An optical transmitter includes an optical device, a wiring board including a first main surface and a second main surface, the optical device being mounted at a position closer to the second main surface than to the first main surface, a holding member fixed to the wiring board, at a position closer to the first main surface than to the second main surface, and an optical fiber inserted into a through hole of the holding member, where the wiring board includes a wiring pattern of a wiring layer sandwiched between an upper insulating layer and a lower insulating layer, and further includes an opening from which an upper surface and a lower surface of the wiring pattern are exposed, and an end surface of the optical fiber is in contact with the upper surface, and an external electrode of the optical device is bonded to the lower surface.