Image Sensor Focus Detection Pixels 2D Lattice
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Solution Overview
Problem
Conventional image sensors face challenges in detecting focus accurately and efficiently, particularly in high-speed operations and maintaining image quality, due to limitations in phase difference detection methods that require bulky and expensive optical path division systems, and previous techniques fail to meet requirements for focus detection precision and image degradation prevention.
Innovation Solution
An image sensor design that arranges focus detection pixels in a 2-dimensional lattice pattern, allowing for phase difference detection in two directions at arbitrary positions, with focus detection pixels distributed uniformly to detect focus in both lateral and longitudinal directions, reducing image degradation and simplifying calculation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phase difference detection method is used with optical path division means, then focus detection speed is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the image sensing function and focus detection function into a single image sensor device. The focus detection pixels are integrated within the image sensor array, eliminating the need for separate optical path division means and dedicated focus detection sensors. This merging achieves high-speed phase difference focus detection while simplifying the overall device structure.
Solution Approach 2:
The image sensor is designed to perform multiple functions: it serves as both the image sensing device and the focus detection sensor. By making the image sensor universal, the patent eliminates the need for separate dedicated focus detection optical systems, thereby reducing device complexity while maintaining high-speed focus detection capability.
2Measurement precision
If focus detection pixels are arranged in the image sensor, then focus detection precision is improved, but image quality deteriorates
Solution Approach 1:
The patent applies local quality by assigning different functions to different regions of the sensor array. Specific pixels are designated as focus detection pixels with pupil division function, while other pixels serve as image sensing pixels. This localized functional differentiation allows high-precision focus detection without significantly compromising overall image quality, as the majority of pixels remain dedicated to image sensing.
3Measurement precision
If pupil division function is added to image sensor pixels, then phase difference detection capability is improved, but image sensing capability is reduced
Solution Approach 1:
The patent segments the sensor array into different functional regions: image sensing pixels and focus detection pixels. The focus detection pixels are further segmented into multiple light receiving portions that perform pupil division. This segmentation allows each pixel type to be optimized for its specific function, achieving high phase difference detection capability while maintaining overall image sensing capability through the remaining pixels.
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
Enables accurate and high-speed focus detection for objects with luminance distributions in various directions, maintaining image quality by reducing the degradation of output images and simplifying focus detection calculations.
Implementation Method 1
an image sensor capable of sensing at least either still images or moving images using many two-dimensionally arrayed photoelectric conversion elements
Data Source
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AI summary
A focus detection apparatus includes an image forming optical system, an image sensing unit which photoelectrically converts the object image, and a focus detection unit which detects the focus state of the imaging optical system from a pixel signal from the image sensing unit. The focus detection unit includes a first focus detection pixel which divides the exit pupil of the image forming optical system in the first direction and receives a light beam, and a second focus detection pixel which divides the exit pupil of the image forming optical system in the second direction different from the first direction, and receives a light beam. The first and second focus detection pixels are periodically arranged near the lattice points of a 2-dimensional lattice formed from first lattice lines set in a predetermined unit area of the image sensing unit, and second lattice lines crossing the first lattice lines.