Camera Module Drive Control for Fast Auto-Focusing
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Solution Overview
Problem
Conventional camera modules with auto-focusing functions consume high electric current and have slow focusing speeds due to the large attraction force between the magnetic member and yoke, leading to inefficient electric current usage and delayed focusing.
Innovation Solution
A drive control apparatus for a camera module that includes a lens module movable along an optical axis, with first and second stoppers defining a maximum moving section, and a controller determining an available moving section by applying a correction value to minimize electric current consumption and enhance focusing speed, using a magnetic member and coils to generate a drive force, and a sensor to detect the lens module's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the lens module moves using the attraction force between the magnetic member and the metallic yoke, then the structure is simple, but the moving speed is slow and the auto-focusing function is delayed
Solution Approach 1:
The patent applies dynamic control by switching between two different driving mechanisms: using electric current for fast forward movement and magnetic attraction for return movement. This dynamic switching allows the system to optimize speed for different directions, resolving the contradiction between simple structure and fast moving speed.
Solution Approach 2:
The patent changes the driving parameter based on movement direction: electric current is applied when moving toward the subject, while magnetic attraction is used when moving away. This parameter change enables the lens module to achieve high speed in both directions without requiring complex dual-drive structures.
2Use of energy by moving object
If the lens module moves in the direction opposite to the magnetic attraction, then the structure remains simple, but the electric current consumption is high
Solution Approach 1:
The patent uses periodic switching between electric current drive and magnetic attraction drive based on the lens module's movement direction. This periodic action allows the system to use the passive magnetic attraction force during return movement, significantly reducing electric current consumption while maintaining simple drive control.
Solution Approach 2:
The patent converts the harmful magnetic attraction force that opposes lens movement into a beneficial returning force. By designing the yoke and magnetic member arrangement, the magnetic attraction automatically pulls the lens module back to its initial position, eliminating the need for additional braking or returning mechanisms and reducing overall energy consumption.
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 reduces electric current consumption, enables faster auto-focusing, and stabilizes the focusing function by minimizing the returning force and using a linear drive waveform, resulting in improved power efficiency and focusing speed.
Implementation Method 1
coils disposed to face the magnetic member with a distance and generating a drive force of the lens module
Implementation Method 2
the attraction force between a magnetic member and a metallic yoke is used when the lens module moves in the other direction
Data Source
Figure 1A
Figure 1B
Figure 1C~1D
AI summary
The present invention discloses a drive control apparatus of a camera module and a method of controlling camera module drive. The drive control apparatus of the camera module according to an embodiment of the present invention comprises: a lens module (400) movable along an optical axis (A, A'); a first (518A) and a second (518B) stopper defining maximum moving section (523) of the lens module (400); and a controller (710) for determining an available moving section by applying a first determined correction value to the maximum moving section so as to make the lens module (400) to move between locations spaced from the first and second stoppers (518A, 518B) with a predetermined distance. According to the present invention, it is advantageously possible to reduce the electric current consumption when performing auto-focusing function.