MEMS Actuator Camera Module Sag Compensation
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Solution Overview
Problem
Micro-electromechanical (MEMS) actuator mounted camera modules face challenges in maintaining accurate focal distance control due to the sag phenomenon caused by varying shooting directions, leading to reliability issues in auto-focusing.
Innovation Solution
A MEMS actuator mounted camera module with sag compensation, comprising a MEMS actuator, a moving unit that outputs electrostatic capacity information, a memory unit storing reference signals, and a signal compensation unit that calculates and adjusts the displacement move signal to compensate for sag-induced errors, ensuring consistent focal distance adjustment across different shooting directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the camera module operates in different shooting directions, then the operational scope of the lens is affected by gravity, but the focal distance control accuracy deteriorates due to sag phenomenon
Solution Approach 1:
The patent changes the operational parameters of the MEMS actuator based on shooting direction. It stores different minimum and maximum electrostatic capacity values (sag compensation values) for different shooting directions (up, down, left, right, horizontal) in a memory unit. The signal compensation unit retrieves and applies the appropriate compensation values based on the current shooting direction, thereby adjusting the electrostatic capacity parameters to compensate for gravity-induced sag and maintain focal distance accuracy across all orientations
Solution Approach 2:
The patent implements a feedback mechanism where the signal compensation unit continuously monitors the electrostatic capacity information from the MEMS actuator moving unit and compares it against stored reference values. Based on this comparison and the detected shooting direction, the system dynamically adjusts the displacement move signal to compensate for sag, creating a closed-loop control system that maintains accuracy despite gravitational variations
2Ease of operation
If the MEMS actuator is used for lens displacement, then the lens position can be adjusted, but the operational scope becomes inconsistent due to gravity-induced sag
Solution Approach 1:
The system adjusts the electrostatic capacity parameters of the MEMS actuator based on shooting direction. By storing direction-specific minimum and maximum electrostatic capacity values and applying appropriate compensation, the system maintains consistent operational scope across all orientations despite gravitational effects on the lens and actuator
3Adaptability or versatility
If the camera module is designed for multi-directional shooting, then versatility is improved, but the reliability of auto-focusing deteriorates due to sag-induced positioning errors
Solution Approach 1:
The patent stores direction-specific electrostatic capacity compensation values in memory and dynamically adjusts the MEMS actuator parameters based on the current shooting direction. This parameter adaptation compensates for gravity-induced positioning errors, maintaining auto-focusing reliability across all shooting orientations
Solution Approach 2:
The signal compensation unit implements a feedback loop that continuously monitors the relationship between electrostatic capacity and lens position, comparing actual performance against expected values. Based on this feedback and the detected shooting direction, the system dynamically adjusts control signals to compensate for sag, ensuring reliable auto-focusing operation in all orientations
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 solution effectively compensates for sag-induced errors, enabling reliable and consistent auto-focusing by accurately controlling the displacement move of the focus-adjustable actuator in any shooting direction, thereby enhancing the reliability of auto-focusing adjustments.
Implementation Method 1
a MEMS actuator mounted with a lens to output a displacement moving force for displacement drive of the lens based on electrostatic force
Data Source
AI summary
The present invention relates to a micro-electromechanical (MEMS) actuator mounted camera module having sag compensation and a sag compensation method using the same, the camera module including a MEMS actuator mounted with a lens; a MEMS actuator moving unit outputting electrostatic capacity information corresponding to position of the lens changed by displacement move and outputting a displacement move signal to the MEMS actuator for controlling the displacement moving force; a memory unit stored with reference signal information corresponding to a maximum displacement move in the displacement move; and a signal compensation unit calculating a step range corresponding to the displacement move of the MEMS actuator based on the electrostatic capacity information outputted from the MEMS actuator moving unit and the reference signal information stored in the memory unit and compensating the displacement moving force of the MEMS actuator based on the calculated step range.