Image Sensor Drive Controller Asynchronous Readout Magnetic Fog
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Solution Overview
Problem
The magnetic fog phenomenon occurs during image sensor signal readout in photographing apparatuses with shared electromagnetic drive systems, causing patterned noise and deteriorating image quality due to synchronization difficulties between drive signals and horizontal synchronizing signals, especially for optical low-pass filter effects.
Innovation Solution
A dual-drive signal approach is implemented, where a first drive signal generator synchronizes with the horizontal synchronizing signal for image shake correction and a second drive signal generator generates a signal difficult to synchronize, with the image sensor drive controller using an asynchronous drive signal during exposure and a synchronous drive signal during readout to prevent magnetic fog and maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electromagnetic drive system is used for both image shake correction and optical low-pass filter effect, then device complexity is reduced, but magnetic fog phenomenon occurs during signal readout causing image quality deterioration
Solution Approach 1:
The patent segments the drive signal generation into two distinct parts: a first drive signal generator for image shake correction that is synchronized with the horizontal synchronizing signal, and a second drive signal generator for optical low-pass filter effect that operates asynchronously. This segmentation allows each generator to be optimized for its specific function while avoiding the magnetic fog phenomenon that occurs when both functions share a single asynchronous drive system.
2Adaptability or versatility
If asynchronous drive signal is used for optical low-pass filter effect, then optical low-pass filter effect is obtained, but magnetic fog phenomenon occurs during signal readout
Solution Approach 1:
The patent applies periodic action by controlling the second drive signal generator to operate only during the exposure period and stop operating during the signal readout period. This periodic operation allows the optical low-pass filter effect to be achieved during exposure while preventing the magnetic fog phenomenon during readout, when the image sensor is particularly sensitive to magnetic field variations.
3Object-affected harmful factors
If drive signal is synchronized with horizontal synchronizing signal, then magnetic fog phenomenon is prevented, but optical low-pass filter effect cannot be obtained
Solution Approach 1:
The patent employs dynamics by making the drive signal characteristics changeable over time. The first drive signal generator maintains synchronization with the horizontal synchronizing signal to prevent magnetic fog, while the second drive signal generator provides asynchronous operation to achieve optical low-pass filter effect. The system dynamically switches between these two modes based on whether the image sensor is in exposure or readout phase.
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 effectively prevents magnetic fog during image sensor readout, ensuring high-quality image data by maintaining image shake correction and optical low-pass filter effects without degrading image quality.
Implementation Method 1
a magnet and a coil are supported to one and the other of the fixed stage and the movable stage, respectively, and in which the movable stage (the image sensor) is driven relative to the fixed stage in directions different from the direction of an optical axis of a photographing optical system (e.g., in a plane orthogonal to the optical axis) by passing an alternating drive signal through the coil
Implementation Method 2
near-field magnetic field varies in accordance with variations of the alternating drive signal that is passed through the coil, an induced current flows through the loop between a power supply and a GND (ground) in the image sensor in accordance with variations of the aforementioned magnetic field
Data Source
AI summary
In a photographing apparatus and a photographing control system, an image sensor drive controller drives an image sensor in a direction which is different from the direction of an optical axis of a photographing optical system via an electromagnetic drive system in accordance with a first drive signal, which is generated by a first drive signal generator, and a second drive signal, which is generated by a second drive signal, during a period of exposure of the image sensor, and drives the image sensor in the direction which is different from the direction of the optical axis of the photographing optical system via the electromagnetic drive system in accordance with the first drive signal, which is generated by the first drive signal generator, during the period of signal readout of the image sensor.