Camera Actuator Driving Mode Switching for Image Signal Noise
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Solution Overview
Problem
Existing camera module actuators introduce noise into image signals during optical image stabilization in low illuminance environments due to the limitations of current driving modes, such as linear and pulse width modulation (PWM) modes, which affect image quality.
Innovation Solution
A driving apparatus for a camera module that determines the driving mode based on external illuminance levels, switching between linear and PWM modes to maintain image signal quality by comparing control signal levels and adjusting the driving mode accordingly, using a magnetic body and driving coil with a controller that generates appropriate control signals to minimize noise introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PWM driving mode is used for optical image stabilization, then power consumption is reduced, but noise is introduced into image signals in low illuminance environments
Solution Approach 1:
The patent changes the driving mode parameter based on illuminance conditions. In high illuminance environments, PWM mode is used to reduce power consumption. In low illuminance environments, linear driving mode is used to prevent noise introduction into image signals. This dynamic parameter adjustment resolves the contradiction between power efficiency and image quality.
2Object-generated harmful factors
If linear driving mode is used for optical image stabilization, then image signal quality is maintained, but power consumption increases
Solution Approach 1:
The patent implements dynamic switching between linear driving mode and PWM driving mode based on real-time illuminance detection. The system is not static but adapts its driving characteristics according to environmental conditions, using linear mode when quality is critical (low light) and PWM mode when power efficiency is prioritized (high light).
3Speed
If driving mode switching is performed without comparison, then response speed is fast, but image signal distortion occurs
Solution Approach 1:
The patent employs feedback control by comparing the control signal level of the previous driving mode with the control signal level of the following driving mode before switching. This comparison mechanism ensures that mode transitions only occur when appropriate, preventing image signal distortion while maintaining reasonable response speed. The feedback loop validates the switching condition before execution.
4Adaptability or versatility
If driving mode switching is performed frequently, then adaptability to illuminance changes is improved, but image signal stability deteriorates
Solution Approach 1:
The patent performs preliminary comparison of control signal levels before executing driving mode switching. This preliminary action prevents unnecessary or premature mode changes that would destabilize image signals. By validating switching conditions in advance, the system maintains signal stability while still adapting to genuine illuminance changes.
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 prevents noise introduction into image signals by optimizing the driving mode based on illuminance levels, ensuring stable image quality during optical image stabilization, particularly in low light conditions.
Implementation Method 1
a magnetic body; a driving coil disposed to face the magnetic body
Data Source
AI summary
An actuator of a camera module includes a magnetic body, a driving coil disposed to face the magnetic body, and a driving apparatus including a driving circuit connected to the driving coil and selectively providing one of a first control signal and a second control signal to the driving circuit according to a driving mode. The driving apparatus compares a level of a control signal of a previous driving mode with a level of a control signal of a following driving mode upon the driving mode being switched.