Image Sensor Dual Readout for Frame Rate and Focus Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increase in the number of pixels, readout speed, and frame rate in image capturing apparatuses leads to a rise in data readout from image sensors, resulting in a reduction in frame rate and increased costs when attempting to broaden data transmission bandwidth and improve signal processing capabilities.
Innovation Solution
An image sensor and capturing apparatus design that includes a pixel portion with unit pixels having one microlens and multiple photoelectric conversion elements, capable of performing mixed and unmixed signal readout operations. This design incorporates a readout portion, sorting portion, and separate output portions for captured image signals and focus detection signals, allowing for efficient data processing and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of pixels and readout speed are increased to improve image quality and frame rate, then the data transmission amount increases, but the frame rate reduces due to longer readout time
Solution Approach 1:
The pixel array is divided into first pixel regions for captured image signals and second pixel regions for focus detection signals. This segmentation allows independent readout paths, enabling parallel processing and reducing the total readout time, thus maintaining frame rate despite increased data volume.
Solution Approach 2:
The patent introduces a dual-output structure with first output portions for captured image signals and second output portions for focus detection signals. This dimensional separation of data streams allows simultaneous transmission of different signal types, effectively increasing the data throughput capacity without bottlenecking the frame rate.
2Productivity
If the data transmission bandwidth is broadened and signal processing capability is improved to handle increased data amount, then the processing speed increases, but the chip costs increase
Solution Approach 1:
The signal processing system is segmented into first signal processing circuits for captured image signals and second signal processing circuits for focus detection signals. This segmentation allows each processing path to be optimized independently and prevents the need for a single high-cost universal processing unit, thereby reducing overall chip cost while maintaining processing speed.
Solution Approach 2:
The patent employs a unified readout portion that serves both captured image signal readout and focus detection signal readout. This multi-functional design eliminates the need for separate readout circuits, reducing device complexity and chip cost while maintaining the ability to process both signal types at high speed.
3Measurement precision
If multiple photodiodes are included in each unit pixel for focus detection, then focus detection capability is improved, but the amount of data read out increases
Solution Approach 1:
The patent extracts focus detection signals from specific second pixel regions and separates them from captured image signals in first pixel regions. This extraction allows focus detection to be performed using only the necessary data portions, reducing the overall data transmission amount while maintaining focus detection precision through dedicated second output portions.
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 effectively suppresses the reduction in frame rate while maintaining low apparatus costs, even with increased data readout from the image sensor, by optimizing signal processing and transmission.
Implementation Method 1
unit pixels each including one microlens and a plurality of photoelectric conversion elements
Data Source
AI summary
An image sensor includes a pixel portion in which unit pixels are arrayed, the unit pixels each including one microlens and a plurality of photoelectric conversion elements, a readout portion configured to read out signals from the pixel portion, the readout portion being capable of performing a first readout operation of reading out mixed signals and a second readout operation of reading out unmixed signals, a sorting portion configured to store signals obtained through the first readout operation and the second readout operation into captured image signals and focus detection signals, a first output portion configured to output the captured image signals sorted by the sorting portion; and a second output portion configured to output the focus detection signals sorted by the sorting portion.