Camera Module Lightning Rod Structure for Gap-Based ESD Protection
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Solution Overview
Problem
Conventional ESD protection methods for camera lenses, such as using plastic covers or grounding structures, result in increased costs, larger product size, and impact optical performance, while TVS diodes require high component costs and lengthy development cycles.
Innovation Solution
A camera module with a lightning rod structure that guides ESD current to a safe location without physically touching the lens retainer, using a gap to establish a conductive path through an ESD bridge component to system ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic cover is used to seal the lens retainer, then ESD protection is provided, but device size increases and optical performance is impacted
Solution Approach 1:
The patent extracts the ESD protection function from the plastic cover approach and implements it through a dedicated ESD bridge component that provides protection without requiring a sealing cover, thereby maintaining compact device size while preserving ESD protection capability
Solution Approach 2:
The ESD bridge component acts as an intermediary element that provides ESD protection path without physically blocking the optical path, serving as a mediator between the lens retainer and ground that does not impact optical performance
2Reliability
If a grounding structure is used to tie the metal retainer to ground, then ESD protection is provided, but focus tuning performance is impacted due to extra force
Solution Approach 1:
The patent segments the ESD protection function from the mechanical focus tuning mechanism by using a separate ESD bridge component that does not physically contact the lens retainer, allowing independent optimization of both ESD protection and focus tuning operations without mutual interference
Solution Approach 2:
The ESD bridge component serves as an intermediary that provides grounding path without mechanically coupling to the lens retainer, eliminating the extra force that would otherwise impact focus tuning performance while maintaining ESD protection
3Reliability
If TVS diodes are added to protect susceptible signals, then ESD protection is provided, but component cost increases and development cycle is lengthened
Solution Approach 1:
The patent extracts the ESD protection function from complex electronic components like TVS diodes and implements it through a simple passive ESD bridge component, reducing component cost and simplifying the development process while maintaining effective ESD protection
Solution Approach 2:
The ESD bridge component provides cost-effective ESD protection using simple passive elements rather than expensive active components like TVS diodes, reducing both component cost and development complexity while achieving the same protection function
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
Provides effective ESD protection without impacting camera focus tuning or causing audio rub and buzz, reducing component costs and device size, and eliminating the need for TVS diodes.
Implementation Method 1
When the lens retainer is stressed by an ESD spark, the gap experiences electrical breakdown and becomes a conductor, establishing a conductive path to guide the ESD current to the safe location through the lightning rod structure
Data Source
AI summary
The present document describes a camera module with electrostatic discharge (ESD) protection. In particular, the camera module includes a lightning rod structure, which guides an ESD current to a safe location (e.g., system ground) when a lens retainer of the camera module is hit by an ESD spark. Due to the impact on camera focus tuning and the risk of audio rub and buzz, the lightning rod structure does not physically touch the lens retainer. As such, a gap separates the lightning rod structure from the lens retainer. When the lens retainer is stressed by an ESD spark, the gap is broken down and a conductive path is established to guide the ESD current to the safe location through the lightning rod structure. In this way, the ESD current flows along a controlled path instead of jumping to arbitrary locations, which protects nearby susceptible circuitry.