Optical Path Folding Element With 2-Axis Rotation Range Extension
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Solution Overview
Problem
Conventional compact camera designs in mobile devices face challenges in reducing height while maintaining optical performance, particularly in folded-lens camera modules where the optical path folding element's limited rotation range restricts the camera's field of view and focal length.
Innovation Solution
An actuator system that enables the optical path folding element to rotate in two degrees of freedom over an extended range, using voice coil motors and magnetic sensors to precisely control the rotation around yaw and pitch axes, decoupling the sensing mechanisms to maintain a lower overall height and improve optical path flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the optical path folding element uses a limited rotation range to maintain compact height, then the camera module height is reduced, but the field of view and focal length are restricted
Solution Approach 1:
The rotation mechanism is divided into two independent degrees of freedom: yaw rotation (around the optical axis) and pitch rotation (tilting the optical path). This segmentation allows each rotation to be optimized independently, enabling extended field of view coverage while maintaining compact overall dimensions through coordinated operation of both rotational degrees of freedom
Solution Approach 2:
The patent transitions from single-axis rotation to two-axis rotation (yaw and pitch), adding another dimension of motion. This dimensional expansion allows the optical path folding element to achieve extended field of view and focal length adjustment without increasing camera module height, as the pitch rotation compensates for the compact yaw rotation range
2Length of stationary object
If magnetic sensors are positioned close to the rotation axis for compact design, then the overall height is reduced, but sensing accuracy may be affected by rotation coupling
Solution Approach 1:
A magnet is introduced as an intermediary element that rotates with the optical path folding element while the magnetic flux sensor remains stationary. This intermediary allows the sensor to be positioned away from the rotation axis, eliminating rotation coupling effects on sensing accuracy while maintaining compact overall design through the magnetic field's ability to transmit rotational information without mechanical contact
Solution Approach 2:
The patent replaces direct mechanical coupling between the rotating element and sensor with a magnetic field-based sensing system. The magnet attached to the rotating element generates a magnetic field that is detected by the stationary magnetic flux sensor, substituting mechanical rotation transmission with electromagnetic field interaction. This eliminates friction, wear, and rotation coupling errors while enabling precise measurement of both yaw and pitch angles
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
This solution allows for a more compact folded camera design with enhanced optical performance by enabling a wider rotation range of the optical path folding element, improving the camera's ability to adjust focus and stabilize images, thus addressing the height constraints and performance limitations of traditional designs.
Implementation Method 1
a voice coil motor (VCM) comprising a magnet and a coil, wherein the magnet is fixedly attached to one of the first sub-assembly or the second sub-assembly, wherein the coil is fixedly attached to the stationary sub-assembly, wherein a driving current in the coil creates a force that is translated to a torque around a respective rotation axis
Implementation Method 2
at least one of the first sensor or the second sensor is a magnetic flux sensor
Data Source
Figure 1A~1B
Figure 1C
Figure 2A
AI summary
Actuators for rotating an optical-path-folding-element with two, first and second, degrees of freedom in an extended rotation range around two respective rotation axes, folded cameras including such actuators and dual-cameras including a folded camera as above together with an upright camera.