Solid-State Imaging Apparatus Reference Voltage Correction
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Solution Overview
Problem
The existing solid-state imaging apparatuses face fluctuations in image signals due to changes in the negative power supply voltage, leading to reduced image quality.
Innovation Solution
A solid-state imaging apparatus and method that includes a pixel operating at a first ground potential, an analog-digital converter operating at a second ground potential higher than the first, a reference voltage generation unit, and a correction unit that adjusts the reference voltage based on changes in the first ground potential to stabilize the image signal conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative power supply voltage is applied to pixels to extend dynamic range and reduce noise effect, then the dynamic range is extended and noise resistance is improved, but image signals fluctuate when the negative power supply voltage changes due to load fluctuation
Solution Approach 1:
The patent implements a feedback mechanism where the ground potential correction unit continuously monitors changes in the ground potential of the pixel array unit and automatically adjusts the ground potential to compensate for voltage fluctuations. This closed-loop control stabilizes the image signals despite variations in the negative power supply voltage caused by load fluctuations.
Solution Approach 2:
The patent introduces a ground potential correction unit as an intermediary component between the negative power supply and the pixel array unit. This intermediary actively compensates for voltage fluctuations by adjusting the ground potential, thereby isolating the pixel array from the instability of the power supply while maintaining the extended dynamic range benefits.
2Quantity of substance
If the ground potential of pixels is lowered to extend dynamic range, then the dynamic range is improved, but the ground potential changes due to negative power supply voltage changes causing image signal fluctuations
Solution Approach 1:
The ground potential correction unit employs feedback control to detect ground potential variations and automatically adjust compensating voltages, maintaining stable ground potential despite negative power supply fluctuations while preserving the extended dynamic range achieved through the lowered ground potential.
Solution Approach 2:
The patent dynamically adjusts the ground potential parameter in response to power supply voltage changes. By actively modifying the ground potential to counteract fluctuations, the system maintains both the extended dynamic range (achieved through the lowered ground potential) and signal stability (maintained through active compensation).
Data Source
AI summary
To reduce fluctuations in image signals when the voltage of a negative power supply supplied to pixels changes. A pixel operates based on a first ground potential applied to a first ground line and outputs an analog image signal according to emitted light. An analog-digital converter operates based on a second ground potential applied to a second ground line, the second ground potential higher than the first ground potential, and converts the analog image signal into a digital image signal based on a reference voltage as a standard for the conversion. A reference voltage generation unit operates based on the second ground potential and generates the reference voltage. A reference voltage correction unit corrects the reference voltage generated according to a change in the first ground potential and supplies the reference voltage to the analog-digital converter.