Column-Parallel Image Sensor ADC for Dark Defect Detection
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Solution Overview
Problem
The existing solid-state imaging devices face challenges with the dark defect phenomenon, which results in a large circuit configuration due to the need for additional light level detection circuits and can adversely affect analog signals.
Innovation Solution
A solid-state imaging device with a column parallel analog-digital converter unit that includes a comparator to compare pixel signals with a reference line and a counter to measure comparison time, allowing for dark defect detection and prevention without additional circuitry in the analog signal path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light level detection circuit is added to detect dark defect, then dark defect detection capability is improved, but circuit scale increases
Solution Approach 1:
The patent merges the dark defect detection function with the existing analog-digital converter by utilizing its comparator. The comparator originally used for analog-to-digital conversion is repurposed to detect dark defects by comparing pixel signals with a reference line, eliminating the need for a separate light level detection circuit and reducing overall circuit scale.
Solution Approach 2:
The comparator in the analog-digital converter is given multi-functionality: it serves both for analog-to-digital conversion and for dark defect detection. This universal use of the comparator allows the system to perform dark defect detection without adding dedicated detection circuitry, thereby improving reliability while maintaining circuit simplicity.
2Reliability
If an analog sensing detection circuit is added in the analog signal path, then dark defect detection is improved, but the analog signal itself might be adversely affected
Solution Approach 1:
The patent uses the comparator as an intermediary element that processes pixel signals without directly interfering with the analog signal path. The comparator compares the analog pixel signal with a reference voltage level to detect dark defects, acting as a mediator that enables detection while maintaining signal integrity through the existing conversion architecture.
Solution Approach 2:
The existing analog-digital converter performs self-service by using its own comparator for dual purposes: normal analog-to-digital conversion and dark defect detection. This eliminates the need for separate detection circuitry that would otherwise interfere with or add complexity to the analog signal path.
3Manufacturing precision
If correction signal circuits are added before A/D converter, then signal correction capability is improved, but circuit configuration becomes large scale
Solution Approach 1:
The patent combines the signal correction function with the analog-digital conversion process by using the comparator to detect dark defects and trigger correction. Rather than adding separate correction circuits before the A/D converter, the system integrates detection and correction capabilities within the existing converter architecture, maintaining precision while reducing circuit scale.
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 simplifies the circuit design and prevents dark defects without affecting the analog signal, reducing the need for exclusive light level detection circuits and minimizing adverse effects on the analog signal.
Implementation Method 1
a signal is generated in photoelectric conversion done by a means for photoelectric conversion
Data Source
AI summary
A solid-state imaging device including: an analog-digital converter unit in column parallel arrangement, the analog-digital converter unit having a plurality of pixels arranged to convert an incident light quantity to an electric signal, in which an analog signal obtained from the pixel is converted into a digital signal, wherein the analog-digital converter unit is configured of: a comparator operable to compare a value of a column signal line from which an analog signal obtained by the pixel is outputted with a value of a reference line, and a counter operable to measure a time period by the time when comparison done by the comparator is finished and to store the comparison result, wherein the solid-state imaging device further includes: a module for controlling an output of the comparator operable to control the output of the comparator depending on the output of the comparator.