Optical Encoder Chip Soldered to PCB for Vibration Resistance
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Solution Overview
Problem
Rotary encoders in industrial applications face issues with bond wires coming loose due to vibrations and temperature changes, leading to costly malfunctions and production drops, as they require expensive clean room environments for manufacturing and mechanical protection.
Innovation Solution
An encoder device with a light-sensitive semiconductor chip connected to a second printed circuit board via solder or electrically conducting glue, eliminating the need for bond wires and allowing production in normal facilities, providing mechanical protection and improved signal quality with integrated amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to connect the light sensitive semiconductor chip to the circuit board, then electrical connection is achieved, but the bond wires become vulnerable to vibrations and temperature changes causing malfunctions
Solution Approach 1:
The patent removes the bond wires from the system entirely and replaces them with a direct solder connection between the light sensitive semiconductor chip and the circuit board. This extraction of the vulnerable bond wire component eliminates the reliability issue caused by vibration and temperature sensitivity while maintaining the essential electrical connection function.
Solution Approach 2:
The patent replaces the mechanical wire bonding system with a soldering process that creates a more robust metallurgical bond. The solder connection provides superior mechanical strength and thermal stability compared to bond wires, substituting a fragile mechanical assembly with a more reliable joined structure.
2Ease of manufacture
If wire bonding is used to connect the light sensitive semiconductor chip, then electrical connection is achieved, but expensive clean room environment is required for manufacturing
Solution Approach 1:
The patent eliminates the clean room requirement by removing the wire bonding process from the manufacturing workflow. By using direct solder connections, the manufacturing process can be performed in standard fabrication environments, dramatically reducing facility costs and enabling more automated production while maintaining connection reliability.
3Object-affected harmful factors
If silicon is used to protect against humidity and mechanical contact, then protection is provided, but the silicon moves with temperature changes causing bond wires and semiconductor to come loose
Solution Approach 1:
The patent removes the protective silicon structure that caused thermal expansion issues and replaces it with a rigid circuit board assembly. The circuit board provides stable mechanical support and environmental protection without the temperature-dependent dimensional changes that plagued the silicon protection approach, maintaining both protection and structural stability.
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 reduces production costs, eliminates the need for clean room environments, enhances signal quality, and improves reliability by avoiding bond wire-related issues, enabling faster and more automated production.
Implementation Method 1
The detector includes at least one light-sensitive semiconductor chip which delivers the electric signal in relation to the amount of light that is received by the light sensitive semiconductor chip
Implementation Method 2
The first PCB contact area is connected to the first chip contact area by solder, electrically conducting glue, ohmic contact, etc.
Data Source
AI summary
An encoder device for optical detection of movement or position includes a first terminal for delivery of an electric measurement code signal. The encoder device further includes a first printed circuit board, a detector mounted on the first printed circuit board, and a code device provided with a pattern. The detector and the code device are displaceable relative to each other, wherein the detector is adapted to generate the electric measurement code signal in dependence on the relative displacement. The detector includes at least one light-sensitive semiconductor chip having a first light-sensitive chip surface and a second chip surface on opposing sides. The first light-sensitive chip surface has a first chip contact area for an electrical connection. The encoder device further includes a second printed circuit board positioned between the detector and the code device, wherein the second printed circuit board is shaped so as to allow the passage of light from the code device to the first light-sensitive chip surface. The second printed circuit board has a first PCB contact area connected to the terminal, wherein the first PCB contact area is connected to the first chip contact area by solder, electrically conducting glue, ohmic contact, etc.