Dual-Photodiode Image Sensor Layout for Faster Focus Adjustment
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Solution Overview
Problem
Existing image sensors face challenges in efficiently capturing and processing signals from multiple photoelectric conversion units, which hinders accurate focus adjustment in imaging devices.
Innovation Solution
The image sensor incorporates pixels with two photoelectric conversion units per pixel, allowing simultaneous transfer and reading out of charges from different regions of the lens pupil, enabling faster and more accurate focus detection through phase difference detection methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple photoelectric conversion units are connected to corresponding floating diffusion units in existing image sensors, then signal reading is possible, but focus adjustment speed and accuracy are hindered due to sequential processing limitations
Solution Approach 1:
The image sensor divides each pixel into multiple photoelectric conversion units (first and second photodiodes) that can be independently controlled and read out. This segmentation allows simultaneous reading of signals from different units through separate transfer units, enabling parallel processing for faster and more accurate phase difference detection without the sequential processing limitations of conventional sensors.
2Productivity
If sequential reading of charges from photoelectric conversion units is used, then device complexity is reduced, but focus detection accuracy and speed are compromised
Solution Approach 1:
The patent combines multiple transfer units (first and second transfer units) within each pixel structure, allowing simultaneous transfer and reading of charges from different photoelectric conversion units. This merging of transfer capabilities enables parallel signal processing, achieving both high processing speed and accurate focus detection while maintaining a relatively compact pixel structure that doesn't excessively increase device complexity.
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 enhances focus adjustment speed and accuracy by allowing simultaneous reading and processing of signals from different lens regions, improving image capture quality and focus adjustment in imaging devices.
Implementation Method 1
a first photoelectric conversion unit that photoelectrically converts light that has passed through a micro lens and generates a first charge
Implementation Method 2
a second photoelectric conversion unit that photoelectrically converts light that has passed through the micro lens and generates a second charge
Data Source
AI summary
An image sensor includes: a first and a second pixel, each of which includes a first photoelectric conversion unit that photoelectrically converts light that has passed through a micro lens and generates a first charge, a second photoelectric conversion unit that photoelectrically converts light that has passed through the micro lens and generates a second charge, an accumulation unit that accumulates at least one of the first charge and the second charge, a first transfer unit that transfers the first charge to the accumulation unit, and a second transfer unit that transfers the second charge to the accumulation unit; and a control unit that outputs, to the first transfer unit of the first pixel and to the second transfer unit of the second pixel, a signal that causes the first charge of the first pixel and the second charge of the second pixel to be transferred to their accumulation units.