Phase Difference Pixel Sensor Focus Adjustment
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Solution Overview
Problem
Existing imaging devices face challenges in maintaining focus precision during continuous autofocus mode, especially when capturing moving subjects, due to ranging dispersion caused by the arrangement of phase difference detection pixels on the image sensor, leading to reduced image quality and unstable focus tracking.
Innovation Solution
The implementation of a digital camera system that performs rapid shooting and focuses adjustment using both focus detection signals from phase difference detection pixels, with first and second focus detection operations based on signals generated during and after exposure, allowing for correction and improved focus tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase difference detection pixels are arranged densely on the image sensor to improve focus detection precision, then focus detection precision is improved, but image quality degradation becomes significant
Solution Approach 1:
The patent divides the image sensor into multiple regions with different pixel arrangements. Some regions have phase difference detection pixels arranged densely for high-precision focus detection, while other regions maintain regular pixel arrangements for high-quality image capture. This segmentation allows the system to achieve both goals simultaneously by assigning different functions to different spatial zones.
Solution Approach 2:
The patent implements local quality by creating zones with different pixel densities and functions. Phase difference detection pixels are concentrated in specific regions where focus detection is most needed, while other regions maintain standard imaging pixels for optimal image quality. This local differentiation ensures that each region performs its designated function with high effectiveness.
2Object-affected harmful factors
If phase difference detection pixels are arranged coarsely and discretely to reduce image quality degradation, then image quality is maintained, but focus detection precision and ranging accuracy are lowered
Solution Approach 1:
The patent segments the sensor to have dedicated phase difference detection regions with dense pixel arrangements alongside regular imaging regions. This allows coarse overall arrangement (maintaining image quality) while having local dense clusters (maintaining focus precision).
Solution Approach 2:
The patent merges phase difference detection functionality with regular imaging pixels in certain regions, creating hybrid zones where both functions can operate. This combination allows the system to maintain image quality while still achieving sufficient focus detection accuracy through the integrated pixel design.
3Measurement precision
If multiple focus detection operations are performed during rapid shooting to reduce ranging dispersion, then focus precision is improved, but processing time and system complexity increase
Solution Approach 1:
The patent performs preliminary focus detection using phase difference detection pixels before and during rapid shooting sequences. By conducting initial focus assessment and continuous monitoring, the system can quickly adjust for ranging dispersion without requiring complex post-processing of multiple full focus detection sequences.
Solution Approach 2:
The patent implements feedback mechanisms where focus detection results from multiple operations are continuously monitored and used to adjust subsequent focus operations. This feedback loop allows the system to reduce ranging dispersion by adapting to actual focus conditions in real-time, rather than relying on fixed complex processing of all detected values.
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 enhances focus precision and stability during continuous autofocus, reducing the impact of ranging dispersion and improving image quality by utilizing multiple focus detection signals across exposures.
Implementation Method 1
phase difference detection pixels that generate pairs of focus detection signals by subjecting light flux that has passed through an optical system, including a focus lens, to pupil division, receiving light and carrying out photoelectric conversion
Data Source
AI summary
An imaging device comprises an image sensor on which phase difference detection pixels are formed, a rapid shooting controller that carries out rapid shooting of still pictures by causing operation of the image sensor, and generates and stores image data based on image signals output by the image sensor, and a controller for focusing control that carries out the rapid shooting and causes operation of the image sensor between one exposure of the rapid shooting and the next to carry out first focus detection based on focus detection signals generated by the phase difference detection pixels, carries out second focus detection based on focus detection signals generated by the phase difference detection pixels as a result of the rapid shooting, and carries out focus adjustment based on results of the first focus detection and results of the second focus detection.