Camera Module Stop Module for LED Flicker Mitigation
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Solution Overview
Problem
Camera modules in vehicles face image degradation due to temperature changes and flickering from light-emitting diodes (LEDs), which is challenging to address with existing exposure time adjustments, leading to image saturation and reduced dynamic range.
Innovation Solution
A camera module design featuring a stop module with adjustable blades and a magnet-driven mechanism that allows for precise control of exposure time by varying the size of incidence holes, enabling effective LED flicker mitigation (LFM) across different illumination conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposure time is increased to implement LED flicker mitigation, then the flicker is reduced, but the image becomes saturated and the dynamic range decreases
Solution Approach 1:
The patent implements a variable aperture stop that can dynamically adjust its opening size during exposure. The stop includes multiple positions (fully open, partially closed, fully closed) that allow the aperture to be adjusted based on lighting conditions. This dynamic adjustment enables the system to use longer exposure times for LED flicker mitigation while preventing image saturation by reducing the aperture opening when necessary.
Solution Approach 2:
The patent changes the physical parameter of the aperture opening size to control the amount of light entering the camera. By varying the aperture diameter, the system can adjust the exposure amount independently of exposure time, allowing longer exposures for flicker mitigation without causing saturation.
2Illumination intensity
If the exposure time is reduced to prevent image saturation, then the dynamic range is maintained, but LED flicker mitigation becomes difficult
Solution Approach 1:
The variable aperture stop allows the system to dynamically adjust the aperture opening during exposure. When LED flicker mitigation is needed, the system can close the aperture to reduce the amount of light entering, enabling longer exposure times without causing saturation, thus maintaining both dynamic range and flicker mitigation capability.
Solution Approach 2:
The system performs preliminary adjustment of the aperture opening before exposure based on detected lighting conditions. By pre-adjusting the aperture size, the system prepares the optimal exposure settings in advance, allowing it to use longer exposure times for flicker mitigation while preventing saturation through the pre-configured aperture restriction.
3Illumination intensity
If the aperture is made large to compensate for dynamic range, then the exposure time must be reduced, but LED flicker mitigation becomes difficult
Solution Approach 1:
The variable aperture stop enables the system to dynamically adjust the aperture size based on real-time lighting conditions. When LED lighting is detected, the system can close the aperture to reduce light intake, allowing longer exposure times for flicker mitigation even when the aperture is relatively large, thus resolving the contradiction between dynamic range compensation and flicker mitigation.
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
The camera module maintains image quality by adjusting exposure time and amount of incident light, effectively mitigating LED flicker and ensuring a wide dynamic range regardless of the surrounding environment, thereby reducing image degradation in vehicles and other applications.
Implementation Method 1
a magnet portion including a driving magnet that opposes a driving coil, and the magnet portion moves back and forth rectilinearly
Data Source
AI summary
A camera module includes a first lens barrel including a first lens, a second lens barrel including a second lens that is aligned with the first lens in an optical axis direction, and a stop module disposed between the first lens barrel and the second lens barrel. The stop module includes blades configured to form one or more incidence holes having various sizes. The stop module includes a magnet portion including a driving magnet opposing a driving coil, and the magnet portion moves back and forth rectilinearly.