Wafer Level Camera Module Active Optical Element Integration
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Solution Overview
Problem
Wafer level camera modules with active optical elements, such as tunable liquid crystal lenses, require electrical connections for auto-focus functionality, which complicates the packaging and assembly process due to the need for mechanical movement of focal planes without mechanical movement.
Innovation Solution
A wafer level camera module with an electrically controllable active optical element, utilizing a flexible printed circuit with a stiffener and surface conductors, including solder balls, to create an electrical conduction path from the active optical element to the mounting surface, allowing for reliable electrical contact and compatibility with automatic pick-and-place processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an active optical element is added to enable auto-focus functionality, then the camera module gains variable focus capability, but the packaging complexity increases due to the need for electrical connections
Solution Approach 1:
The patent combines the electrical connection structure with the lens mounting structure by integrating the printed circuit board into the lens barrel assembly. The PCB is positioned to provide both mechanical support for the active optical element and electrical connectivity, merging two functions into a single integrated structure that reduces packaging complexity.
Solution Approach 2:
The patent introduces a printed circuit board as an intermediary component that facilitates electrical connection between the active optical element and the external environment. The PCB acts as a mediator that also provides mechanical positioning and support, enabling the active element to be electrically connected without adding significant packaging complexity.
2Adaptability or versatility
If electrical connections are added for the active optical element, then auto-focus functionality is enabled, but the assembly process becomes more complex
Solution Approach 1:
The patent merges the electrical connection function with the mechanical mounting function by integrating the PCB into the lens barrel. This allows the active optical element to be connected electrically and mechanically through a single integration step, simplifying the assembly process rather than adding separate connection steps.
Solution Approach 2:
The printed circuit board serves multiple functions simultaneously: it provides electrical connectivity to the active optical element, mechanical support and positioning, and structural integration with the lens barrel assembly. This multi-functionality reduces the number of separate components and assembly steps required.
3Reliability
If a flexible printed circuit is used to accommodate lens height variations, then reliability is improved, but the device complexity increases
Solution Approach 1:
The patent employs a flexible printed circuit board that can bend and accommodate variations in lens stack height. The flexibility of the PCB allows it to conform to different heights while maintaining reliable electrical connection, eliminating the need for rigid positioning structures or additional compliance components.
Solution Approach 2:
The flexible PCB allows the electrical connection structure to adapt to parameter variations in the lens stack height. By changing the physical state of the circuit board from rigid to flexible, the system can accommodate height variations without requiring additional adjustment mechanisms or complex positioning systems.
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
Enables reliable electrical connection and auto-focus functionality without additional assembly steps, ensuring proper alignment and strain relief, facilitating integration into portable devices like cellular phones with efficient reflow soldering and reduced manufacturing complexity.
Implementation Method 1
The module has an electrical conduction path from the active optical element to a mounting surface of the camera module, where a surface conductor is located. The surface conductor is in electrical contact with the electrical conduction path
Implementation Method 2
The surface conductor includes at least one solder ball that is part of a ball grid array-like package when the camera module is fully assembled
Data Source
AI summary
A wafer level camera module can be easily connected to a host device via mounting surface contacts. The module includes an electrically controllable active optical element and a flexible printed circuit that provides electrical connection between the optical element and surface conductors on a mounting surface of the module. The surface conductors can be a group of solder balls, and the module can have another group of solder balls that make connection to another electrical component of the module, such as an image sensor. All of the solder balls can be coplanar in a predetermined grid pattern, and all of the components of the device can be surrounded by a housing such that the camera module is an easily mounted ball grid array type package.