Phase Difference Pixel Arrangement for Auto Focusing Speed and Accuracy
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Solution Overview
Problem
Existing auto focusing technologies, such as contrast AF and phase difference AF, face challenges in achieving accurate focus without blurring the image, with phase difference AF having lower focus accuracy and requiring careful lens movement, while also needing optimal arrangement of phase difference pixels to balance image resolution and detection accuracy.
Innovation Solution
A solid-state image sensor and auto focusing method that arranges phase difference pixels in a matrix pattern with specific skip readout modes, allowing for phase difference detection without blurring the image, by reading out data from phase difference pixels and general pixels in overlapping regions, enabling rapid and accurate focus adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phase difference pixels are arranged in a solid-state image sensor to enable phase difference auto focusing, then focusing speed is improved, but focus accuracy deteriorates compared to contrast AF
Solution Approach 1:
The patent combines phase difference pixels and general pixels into a unified matrix structure where phase difference pixels are strategically positioned within the general pixel array. This merging allows the system to leverage both phase difference detection (for speed) and general pixel data (for accuracy) simultaneously, resolving the contradiction between focusing speed and focus accuracy
Solution Approach 2:
The solid-state image sensor is designed to perform multiple functions: it can operate in phase difference auto focusing mode using dedicated phase difference pixels, in contrast auto focusing mode using general pixels, or in a hybrid mode combining both approaches. This multi-functionality allows the system to achieve both rapid focusing and accurate focus detection
2Measurement precision
If too many phase difference pixels are arranged in the solid-state image sensor, then phase difference detection accuracy is improved, but image resolution deteriorates
Solution Approach 1:
The patent applies local quality by positioning phase difference pixels at specific strategic locations within the matrix rather than distributing them uniformly. Phase difference pixels are placed at positions that optimize phase difference detection while minimizing impact on overall image resolution, creating different functional zones within the sensor array
Solution Approach 2:
The patent uses a partial action approach by incorporating only a subset of pixels as phase difference pixels rather than converting the entire array. This partial conversion maintains sufficient phase difference detection capability while preserving the majority of pixels for high-resolution imaging, balancing detection accuracy with image quality
3Speed
If phase difference pixels are arranged for optimal phase difference AF performance, then focusing speed is improved, but performance in other imaging modes may be compromised
Solution Approach 1:
The sensor design ensures compatibility across multiple imaging modes by maintaining a regular matrix structure that works for both phase difference detection and general imaging. The same pixel array can be selectively read out for phase difference AF, contrast AF, live view, still image, or moving image modes, ensuring versatile performance without mode-specific optimization compromises
Data Source
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AI summary
A solid-state image sensor (120) of an electronic device includes a plurality of pixels (R,G,B,P) arranged in a matrix form and having a plurality of phase difference pixels (P) of the plurality of pixels. The plurality of phase difference pixels are arranged at locations of pixels that are commonly read out in a plurality of different skip readout modes.