Image Sensor Parallel Readout for Focus Detection and Capture
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Solution Overview
Problem
Existing image sensors with two photodiodes per pixel face challenges in simultaneous acquisition of focus detection and captured image signals, leading to increased readout time due to sequential signal processing, which is inefficient compared to conventional sensors with one photodiode per pixel.
Innovation Solution
The image sensor design enables parallel readout of image capture and focus detection signals by incorporating first and second photoelectric conversion portions, with dedicated output portions for each, allowing simultaneous output of signals from the first and combined photoelectric conversion portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sequential readout of focus detection signal and captured image signal is performed, then signal acquisition is simplified, but readout time significantly increases
Solution Approach 1:
The pixel array is divided into first pixel units with first photodiodes for focus detection and second pixel units with second photodiodes for captured image acquisition. This segmentation allows independent parallel readout paths, enabling simultaneous acquisition of focus detection signals and captured image signals without sequential processing delays
Solution Approach 2:
The patent introduces a spatial dimension by dividing pixels into different types (first and second pixel units) rather than using a single uniform pixel type. This dimensional differentiation enables multiple signal types to be read out simultaneously through separate output portions, transforming a time-sequential process into a space-parallel process
2Measurement precision
If two photodiodes are provided per pixel for focus detection, then focus detection capability is improved, but readout speed decreases due to sequential processing
Solution Approach 1:
The pixel array is segmented into first pixel units containing first photodiodes dedicated to focus detection and second pixel units containing second photodiodes dedicated to captured image acquisition. This segmentation enables independent parallel readout through separate output portions, maintaining focus detection capability while achieving high-speed simultaneous readout of both signal types
Solution Approach 2:
The image sensor is designed with multi-functionality by incorporating both first and second photodiodes that can operate simultaneously. The sensor can concurrently perform focus detection using first photodiodes and captured image acquisition using second photodiodes, with both functions operating in parallel without interfering with each other's speed or precision
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 approach significantly reduces readout time, enabling high-speed acquisition of both focus detection and captured image signals, thereby improving the frame rate and efficiency of image capturing processes.
Implementation Method 1
each pixel unit having first and second photoelectric conversion portions
Data Source
AI summary
An image sensor, comprising a pixel region in which a plurality of pixel units are arranged, each pixel unit having first and second photoelectric conversion portions, a first output portion that outputs, outside of the image sensor, a first signal based on a signal from the first photoelectric conversion portion of the pixel units, and a second output portion that outputs a second signal based on a signal from the first photoelectric conversion portion and a signal from the second photoelectric conversion portion of the pixel units, wherein output of the first signal from the first output portion and output of the second signal from the second output portion are performed in parallel.