Smartphone Image Stabilizer Lens Position Control
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Solution Overview
Problem
Conventional image stabilizers in smartphones, which use a shared AF and image stabilizing lens, face performance issues due to the lack of precise distance measurement between the lens and imaging element, leading to suboptimal image stabilization corrections.
Innovation Solution
An image stabilizer system that includes a first position sensor for detecting lens movement in the camera shake direction, a distance signal calculation unit for determining the distance between the lens and imaging element, and a target position signal calculation circuit that generates drive signals based on the detected positions and angular velocity to accurately stabilize the lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a shared AF and image stabilizing lens is used in smartphones, then the device size is reduced, but the image stabilization performance deteriorates due to lack of precise distance measurement
Solution Approach 1:
The patent divides the lens position detection into two independent components: a first position sensor for detecting camera shake direction movement and a second position sensor for detecting AF direction movement. This segmentation allows precise measurement of distance changes during focusing operations, resolving the contradiction between compact device size and measurement precision.
Solution Approach 2:
The patent implements feedback control by using the second position sensor to detect lens position in the AF direction and feeding this information back to calculate accurate distance signals. This feedback mechanism enables precise distance measurement in the shared lens system, improving image stabilization performance without increasing device volume.
2Device complexity
If open-loop control is used for lens position, then the device complexity is reduced, but the image stabilization accuracy deteriorates due to lack of position feedback
Solution Approach 1:
The patent introduces feedback control by incorporating position sensors that detect lens position in both camera shake direction and AF direction. The detected position information is fed back to calculate accurate target position signals, significantly improving lens position control accuracy while maintaining reasonable system complexity through efficient sensor integration.
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 enhances image stabilization performance by accurately calculating the target position of the lens in the camera shake direction, improving correction precision and reducing errors associated with shared lens usage in smartphones.
Implementation Method 1
a first position sensor configured to detect a position of the lens that moves in the camera shake direction, and output a first detection position signal
Implementation Method 2
a distance signal calculation unit configured to receive a second detection position signal that indicates a position of the lens that moves in the auto-focus direction, and calculate a distance signal between the imaging element and the lens
Implementation Method 3
a target position signal calculation circuit configured to receive the distance signal, and an angular signal that indicates an angle at which the lens is inclined from the optical axis direction, and calculate a target position signal of the lens in the camera shake direction
Implementation Method 4
a drive signal generation unit configured to generate a drive signal that drives the lens in the camera shake direction, on the basis of the target position signal and the first detection position signal
Data Source
AI summary
The present invention relates to an image stabilizer and a camera module. The image stabilizer for a lens that moves, with respect to an imaging element, in an auto-focus direction and a camera shake direction, includes a first position sensor, a distance signal calculation unit, a target position signal calculation circuit and a drive signal generation unit. A first detection position signal that indicates a position of the lens that moves in the camera shake direction, a second detection position signal that indicates a position of the lens that moves in the auto-focus direction, and an angular velocity signal that indicate an angular velocity when the lens is inclined from the optical axis direction to output a drive signal. A drive unit moves the lens in the camera shake direction depending on the drive signal.