Phase-Detection Pixel Layout for Edge Sensitivity and Light Confinement
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Solution Overview
Problem
Current imaging elements with phase difference detection pixels face challenges in optimizing the arrangement of light-receiving and light-shielding regions to enhance sensitivity and accuracy in phase difference detection, particularly at the edges of the imaging element.
Innovation Solution
The imaging element is designed with a specific arrangement of photoelectric conversion and charge holding units, where the light-receiving and light-shielding regions are positioned in a way that the light-receiving regions of adjacent pixels overlap, allowing for efficient light confinement and improved sensitivity, especially at the edges, by configuring the light-receiving regions to be larger laterally and the light-shielding regions to be positioned on either side of the light-receiving regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light-receiving region is made larger laterally to improve sensitivity, then the sensitivity and phase difference detection accuracy are improved, but the light-shielding regions cannot be properly positioned on either side, reducing light confinement effectiveness
Solution Approach 1:
The patent transitions from a conventional square photoelectric conversion unit to a rectangular configuration where the width in the second direction (lateral dimension) is larger than the width in the first direction. This dimensional change allows the light-receiving region to be expanded laterally for improved sensitivity while still maintaining proper positioning of light-shielding regions on both sides in the first direction, thus resolving the contradiction between sensitivity and light confinement.
2Quantity of substance
If the photoelectric conversion unit width is increased in the second direction to improve light reception, then the light-receiving region area is increased, but the charge holding unit width must also be increased, increasing device complexity
Solution Approach 1:
The patent applies local quality by making the photoelectric conversion unit rectangular rather than square, with the width in the second direction being larger than the width in the first direction. This allows the light-receiving region to be expanded specifically in the lateral direction where it is needed for improved sensitivity, while the charge holding unit maintains a more compact configuration, thus increasing light reception capacity without proportionally increasing overall device complexity.
3Object-affected harmful factors
If light-shielding regions are positioned on both sides of the light-receiving region to improve light confinement, then light leakage is reduced, but the light-receiving region area is reduced, lowering sensitivity
Solution Approach 1:
The patent resolves this contradiction by changing the dimensional proportions of the photoelectric conversion unit from square to rectangular, with the width in the second direction being larger than the width in the first direction. This allows the light-receiving region to be expanded in the lateral direction to maintain or improve sensitivity, while light-shielding regions are properly positioned on both sides in the first direction to prevent light leakage, thus achieving both light confinement and high sensitivity simultaneously.
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 the derivation accuracy of phase differences and improves image quality by ensuring high sensitivity and accurate focal point adjustment, even at the edges of the imaging element.
Implementation Method 1
a photoelectric conversion unit and a charge holding unit that holds charges transferred from the photoelectric conversion unit
Data Source
AI summary
An imaging element includes plural pixels in each of which a photoelectric conversion unit and a charge holding unit that holds charges transferred from the photoelectric conversion unit are arranged in a first direction, the plural pixels include a first pixel, in the photoelectric conversion unit of the first pixel, a light-receiving region and a light shielding region are arranged in a second direction intersecting with the first direction, and a width of the photoelectric conversion unit in the second direction is larger than a width of the charge holding unit in the second direction.