Image Sensor Pixel Readout Control for Focus Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensors require longer readout times for focus detection signals using phase difference detection methods, as they need to read out signals from both focus detection and imaging pixels, leading to inefficiencies in signal acquisition and potential noise issues due to differing reset signal timings.
Innovation Solution
An image sensor with a pixel array where focus detection and imaging pixels are arranged in alternating patterns, allowing for differential readout control between pixel rows, enabling independent timing for focus detection and imaging signal readout, thus reducing overall readout time and noise distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signals are read out from both focus detection pixels and imaging pixels using the same readout sequence, then both signals can be acquired, but the readout time is significantly extended
Solution Approach 1:
The patent divides the pixel array into two distinct groups: focus detection pixels and imaging pixels. Each group has its own dedicated readout circuit and can be read out independently through separate signal lines. This segmentation allows simultaneous or staggered readout of both pixel types without interfering with each other, thereby reducing the total readout time while ensuring both focus detection and imaging signals are acquired
Solution Approach 2:
The patent introduces a new dimension to the readout architecture by adding separate readout paths and control mechanisms for focus detection pixels versus imaging pixels. Instead of sequentially processing all pixels through a single readout channel, the system creates parallel readout dimensions, allowing independent timing and processing of focus detection signals and imaging signals, thus eliminating the time penalty of sequential readout
2Productivity
If reset signals are read out at different timings for focus detection and imaging pixels, then readout flexibility is improved, but noise distribution becomes uneven
Solution Approach 1:
The patent applies different readout control strategies to different pixel groups based on their specific requirements. Focus detection pixels can have their reset signals read out at optimized timings for phase difference detection, while imaging pixels use reset timings optimized for image quality. This local quality approach allows each pixel type to operate at its optimal performance point without compromising the other
Solution Approach 2:
The patent enables independent adjustment of readout parameters (such as reset timing, readout speed, and signal processing gains) for focus detection pixels versus imaging pixels. By changing these parameters locally for each pixel group, the system achieves both high readout efficiency and uniform noise distribution, as each group's parameters are optimized for its specific function while maintaining overall system balance
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 shortens the readout time for both focus detection and imaging signals, while minimizing noise variations, thereby enhancing image quality and efficiency in phase difference detection methods.
Implementation Method 1
a photoelectric conversion portion of each pixel is divided into two regions that receive, via the micro lens, light beams
Data Source
AI summary
Disclosed is an image sensor capable of efficiently implementing readout of signals for focus detection and image signals. The disclosed image sensor has a first type of pixel row and a second type of pixel row in which focus detection pixels and imaging pixels are respectively arranged in a first pattern and a second pattern. Readout control that differs between the first type of pixel row and the second type of pixel row is performed, according to the arrangement pattern of the focus detection pixels and the imaging pixels.