Opto-Electric Hybrid Flexible PCB Bonding Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing opto-electric hybrid flexible printed circuit boards lies in achieving compatible bonding strength and precision of the optical semiconductor element's mounting position, as conventional ultrasonic bonding methods struggle to apply sufficient pressure on flexible optical waveguides made of low elastic modulus materials, leading to inadequate bonding strength and decreased signal light power due to potential displacement during the bonding process.
Innovation Solution
The method involves forming a core with varying widths at the ends of the flexible optical waveguide, where the width of one end is larger than the light-emitting part and the other end is smaller than the light-receiving part, allowing for increased tolerance and precise positioning, and using ultrasonic bonding to connect the electrodes to the pads on the flexible printed circuit board, ensuring effective bonding while minimizing signal light power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic bonding is used to mount optical semiconductor elements on flexible printed circuit boards, then bonding strength is improved, but manufacturing precision deteriorates due to element displacement during bonding
Solution Approach 1:
The patent applies preliminary positioning actions by forming positioning protrusions on the flexible printed circuit board and corresponding positioning grooves on the optical semiconductor element before bonding. These positioning structures are created in advance to ensure accurate alignment, preventing displacement during the ultrasonic bonding process while maintaining bonding strength.
Solution Approach 2:
The patent introduces positioning protrusions and positioning grooves as intermediary structures that mediate between the bonding requirement and positioning requirement. These intermediary features facilitate both precise positioning and effective bonding by providing a mechanical interface that maintains alignment during the bonding process.
2Strength
If pressure is increased during ultrasonic bonding to improve bonding strength, then bonding quality improves, but element displacement increases reducing mounting precision
Solution Approach 1:
The positioning protrusions and grooves are formed in advance to establish a mechanical interlock that constrains the optical semiconductor element during bonding. This preliminary positioning action allows the application of bonding pressure without causing significant displacement, as the element is already mechanically constrained by the positioning structures.
Solution Approach 2:
The positioning protrusions and grooves act as intermediary structures that distribute and control the pressure application during bonding. They provide a mechanical interface that maintains alignment while allowing sufficient pressure to be applied for strong bonding, thus mediating between the conflicting requirements of bonding strength and positioning precision.
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 approach enhances the bonding strength between the optical semiconductor elements and the flexible printed circuit board while maintaining precision, thereby improving the yield and stability of opto-electric hybrid flexible printed circuit boards by reducing signal light power loss and position displacement.
Implementation Method 1
ultrasonic bonding (gold-gold ultrasonic bonding or the like)
Implementation Method 2
Atomic diffusion induced by the ultrasonic waves allows the electrodes of the optical semiconductor element and the pads of the FPC to be electrically connected
Data Source
AI summary
[Problem to be Solved]To make the strength of bonding between an optical semiconductor element and a flexible printed circuit board compatible with the precision of the mounting position of the optical semiconductor element.[Solution]A manufacturing method according to one aspect of the present invention includes: forming a core 3b such that a width of one end thereof is larger than that of a light-emitting part 4a of a surface light-emitting element 4 and that a width of the other end thereof is smaller than that of a light-receiving part 5a of a surface light-receiving element 5 by patterning a core layer after pasting a cladding layer 3a with the core layer; producing a flexible optical waveguide 3 by pasting a cladding layer 3c having flexibility with the cladding layer 3a to cover the core 3b; pasting the flexible optical waveguide 3 at a predetermined position on a lower face of a flexible printed circuit board 2 via an adhesive sheet 6; and respectively forming, at the one end and the other end of the core 3b, optical path converting mirrors 7 and 8 each of which converts an optical path of signal light due to light reflection on an end face by processing the flexible optical waveguide 3.