CMOS Image Sensor Pixel Power Supply Segmentation
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Solution Overview
Problem
Existing image processing devices, such as CMOS image sensors, face issues with power supply voltage variation and streaking due to voltage fluctuations, which affect signal quality and lead to errors in image output.
Innovation Solution
An image processing device and method that includes a first storage unit for electric charges from a photodiode, a reset unit to reset the voltage, a transfer unit to move charges, a switching unit to control the pixel power source voltage, an output unit to send the stored voltage to a signal line, and a second storage unit to stabilize the DC voltage for the output unit, with the switching unit turned off before resetting and turned on after output completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the switch is turned off to suppress power supply voltage variation, then voltage stability is improved, but streaking occurs due to voltage variation in the SEL line
Solution Approach 1:
The patent segments the power supply system into two independent parts: a first power supply for the pixel circuit and a second power supply for the SEL driver. This segmentation allows each power supply to be controlled independently, enabling the switch to be turned off for voltage stability while the second power supply maintains stable voltage for the SEL line, preventing streaking.
Solution Approach 2:
The patent introduces a second power supply as an intermediary component that specifically powers the SEL driver. This intermediary power supply acts as a buffer that isolates the SEL line from voltage variations caused by switching operations, thereby preventing streaking while allowing the main power supply to be switched off for stability.
2Object-affected harmful factors
If the switch is turned on to maintain SEL line voltage, then streaking is suppressed, but power supply voltage variation affects signal quality
Solution Approach 1:
The patent divides the power supply system into separate segments: the first power supply (with switch) for pixel circuit operation and the second power supply for SEL driver operation. This segmentation allows the second power supply to remain on and stabilize the SEL line, preventing streaking, while the first power supply can be switched off to suppress voltage variation and improve overall voltage stability.
Solution Approach 2:
The second power supply serves as an intermediary that maintains stable voltage for the SEL driver independently of the main power supply's switching state. This intermediary power source ensures the SEL line remains stable and free from streaking artifacts, while allowing the main power supply to be switched off for improved voltage stability.
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 configuration effectively suppresses power supply voltage variation and prevents streaking, improving signal quality by isolating voltage fluctuations and reducing errors between pixels.
Implementation Method 1
The photodiode 15 generates electric charges corresponding to a light receiving amount from an object incident on the photodiode 15
Implementation Method 2
a voltage of a capacitor 16 to which a voltage of a photodiode 15 is transferred
Data Source
AI summary
An image processing device includes: a first storage unit storing electric charges outputted from a photodiode; a reset unit resetting a voltage stored in the first storage unit; a transfer unit transferring electric charges outputted from the photodiode to the first storage unit; a switching unit switching a DC voltage supplied from a supply line of a pixel power source; an output unit outputting the voltage stored in the first storage unit to a signal output line; a second storage unit storing the DC voltage supplied through the switching unit; and a drive unit driving the output unit by receiving the DC voltage stored by the second storage unit as a power source.