Piezo Actuator Camera Module for Miniaturized Autofocus
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Solution Overview
Problem
Conventional camera modules face challenges in miniaturization and precise control due to the bulkiness and limited accuracy of Voice Coil Motors (VCMs) used for autofocus, especially in small-sized devices like smartphones.
Innovation Solution
A camera module design that utilizes piezoelectric actuators to lift and tilt a relatively lightweight image sensor, allowing for auto focusing and handshake compensation, with a flexible PCB and reinforcement members to maintain image sensor flatness and adjust focal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Voice Coil Motor (VCM) is used to move lenses for autofocus, then autofocus function is achieved, but the camera module becomes voluminous and control accuracy is limited
Solution Approach 1:
The patent replaces the Voice Coil Motor (VCM) mechanical system with a piezoelectric actuator system. The piezoelectric actuators convert electrical signals directly into precise mechanical displacement through the piezoelectric effect, eliminating the need for traditional motor mechanisms. This substitution enables more accurate focus control through precise control of the image sensor's position and orientation, while simultaneously reducing the overall camera module volume by removing bulky motor components.
Solution Approach 2:
Instead of moving the heavy lens assembly forward for autofocus as in conventional designs, this patent inverts the approach by moving the lighter image sensor backward relative to the lens. This inversion allows the use of smaller, more precise piezoelectric actuators mounted on the image sensor rather than requiring large motors to move the entire lens assembly, thereby achieving both miniaturization and improved control accuracy.
2Reliability
If image sensor is moved for autofocus and handshake compensation, then focus control and image stability are improved, but device complexity increases
Solution Approach 1:
The piezoelectric actuator system is designed to perform multiple functions simultaneously: autofocus adjustment, handshake compensation, and image sensor stabilization. By mounting multiple piezoelectric actuators on the image sensor in specific configurations, the system can control the sensor's position in multiple degrees of freedom, enabling it to achieve focus adjustment and compensate for device movement without requiring separate dedicated mechanisms for each function.
Solution Approach 2:
The patent combines the autofocus mechanism and handshake compensation mechanism into a single integrated system using piezoelectric actuators mounted on the image sensor. Instead of having separate systems for focus adjustment and image stabilization, the piezoelectric actuators serve both purposes by precisely controlling the image sensor's position and orientation, thereby reducing overall system complexity while maintaining or improving performance.
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
Enables miniaturization of the camera module while providing precise auto focusing and handshake compensation, improving focus control and image stability in small devices.
Implementation Method 1
the actuators may be provided in piezoelectric actuators
Data Source
AI summary
A camera module according to an exemplary embodiment of the present disclosure includes a housing forming an exterior appearance of the camera module, a PCB (Printed Circuit Board) mounted with an image sensor where one end of which is fixed to the housing and the other end is exposed to an outside to be connected to other parts, a lens holder including at least one or more pieces of lenses and so arranged as to be spaced apart from the image sensor at a predetermined distance, and at least two actuators mounted at areas other than an image sensor-mounted area of the PCB, wherein a position of the image sensor is controlled in response to strains of the actuators.