Optical Module Relay Board Slope Wire Bonding
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Solution Overview
Problem
The existing TO-CAN type optical module packaging methods using lead pins and brazing or soldering face challenges in accurately positioning lead pins, leading to increased inductance and high costs due to the use of expensive pellets, while also being difficult to control positionally.
Innovation Solution
The optical module employs a conductive block with through holes and lead pins, a relay board with a sloping surface for wire bonding, and a photoelectric device, using signal and ground wires to minimize costs and reduce inductance by simplifying the bonding process and eliminating the need for expensive pellets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brazing or soldering is used to connect lead pins, then inductance is reduced, but manufacturing cost increases due to expensive pellets
Solution Approach 1:
The patent replaces expensive AuSn solder pellets with inexpensive copper wires for electrical connection. The wire bonding process uses cost-effective materials while achieving the necessary electrical connectivity between the optical component and the circuit board, thereby reducing manufacturing costs without significantly compromising electrical performance.
Solution Approach 2:
The patent substitutes the thermal bonding process (brazing/soldering using heat and molten metal) with a mechanical wire bonding process. Instead of using molten solder to create electrical connections, the invention uses wire bonding techniques where copper wires are mechanically attached to the lead pins and circuit board, replacing the complex thermal-field bonding system with a simpler mechanical connection system.
2Reliability
If brazing or soldering is used to connect lead pins, then inductance is reduced, but position control becomes difficult
Solution Approach 1:
The patent replaces the precision thermal bonding process with wire bonding, which offers greater flexibility in positioning. Wire bonding allows for easier adjustment and compensation of position variations during assembly, as the wires can be routed and connected with less stringent positioning requirements compared to pellet-based brazing or soldering processes.
3Ease of manufacture
If wire bonding is used instead of brazing or soldering, then manufacturing cost is reduced, but inductance may increase
Solution Approach 1:
The patent optimizes wire bonding parameters including wire material (copper), wire diameter, wire length, and bonding pressure to minimize inductance. By carefully controlling these parameters, the invention achieves low-inductance connections that approach the performance of soldered joints while maintaining the cost advantages of wire bonding. The wire length is specifically minimized and the bonding geometry is optimized to reduce parasitic inductance.
Data Source
AI summary
The relay board includes a first end face opposed to and fixed to the first surface of the conductive block, a second end face opposite to the first end face, and a top and a bottom defining thickness of the relay board. The top has a slope at a position closer to the first end face than the second end face. The slope inclines such that the thickness decreases in a direction from the first end face to the second end face. The conductor layers include a signal pattern on the top with part of the signal pattern disposed on the slope, and a first ground pattern extending from the bottom to each of the first end face and the second end face. The signal wire has one end bonded to the signal lead pin and another end bonded to the signal pattern on the slope.