Imaging Element Signal Adder Circuit for Pixel Decimation
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Solution Overview
Problem
Existing imaging devices face challenges in generating high-quality image signals while maintaining operation speed and power consumption within appropriate ranges, and constructing a pixel structure for adding up pixel signals without difficulty, especially when reducing the number of pixel signals outputted from image sensors for high-definition moving images.
Innovation Solution
An imaging element with a Bayer array of color filters, where signals from photoelectric conversion elements are added up in specific patterns to reduce the number of pixel signals read out, using a signal adder circuit to combine signals from different color filters and an A/D converter to convert these signals into digital form, allowing for the generation of high-quality image signals with reduced power consumption and no difficulty in pixel structure construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pixel signals are decimated to reduce the number of pixel signals outputted, then the number of pixel signals is reduced, but sensitivity of outputted image data is reduced
Solution Approach 1:
The patent merges pixel signals from multiple photoelectric conversion elements (specifically, adds up signals from two elements) before outputting them. This combining approach reduces the total number of signals outputted while maintaining sensitivity, as the signals are aggregated rather than simply selected or discarded.
2Quantity of substance
If pixel signals of the same color are added up to reduce the number of pixel signals, then the number of pixel signals is reduced, but it becomes difficult to construct a pixel structure for transmitting signals
Solution Approach 1:
The patent segments the pixel array into unit grids containing multiple photoelectric conversion elements, and processes signals within each segment independently. This segmentation allows for simplified signal transmission architecture while achieving signal aggregation, as each unit grid can be handled separately through its associated floating diffusion region.
3Quantity of substance
If pixel signals are added up and then read out, then the number of pixel signals is reduced, but chromatic noise increases compared to simple decimation
Solution Approach 1:
The patent applies different processing approaches to different color signals within unit grids. Specifically, it adds up signals from photoelectric conversion elements with the same color filtering (e.g., both green elements) while maintaining separate processing for different color types. This localized quality differentiation reduces chromatic noise by ensuring that only signals of the same color are aggregated.
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
The solution enables the generation of high-quality image signals by adding up pixel signals within each unit grid, reducing power consumption and maintaining operation speed, while improving sensitivity and allowing for high-resolution image formation without the need for interpolation.
Implementation Method 1
photoelectric conversion elements provided for the respective color filters, each of which elements outputs an analog signal corresponding to an intensity of light having passed through an associated color filter
Data Source
AI summary
An imaging element includes: a plurality of color filters arranged in a Bayer array; photoelectric conversion elements provided for the respective color filters; a signal adder circuit which carries out additions in each of the unit grids, by (i) adding up signals outputted from two photoelectric conversion elements corresponding to different colors of two color filters out of four color filters, and (ii) adding up signals outputted from two photoelectric conversion elements corresponding to remaining two color filters; and an A/D converter. The imaging element outputs: (i) a first digital image signal where signals of one color out of Ye (yellow) and Cy (cyan), and signals of G, are alternately placed; and (ii) a second digital image signal where signals of an other color out of Ye and Cy, which is different from the one color, and signals of Mg (magenta), are alternately placed.