Phase Difference Pixel Lens Layout to Reduce Detection Error
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Solution Overview
Problem
Conventional imaging elements with a common on-chip lens for phase difference pixels experience reduced detection accuracy due to structural elements not contributing to photoelectric conversion, causing errors in phase difference detection.
Innovation Solution
An imaging element design where individual on-chip lenses are used for each pixel, with a common on-chip lens for adjacent phase difference pixels, and the charge transfer units are positioned between the common and individual on-chip lenses to minimize interference with light collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a common on-chip lens is arranged for multiple phase difference pixels to collect incident light, then light collection efficiency is improved, but detection accuracy of phase difference decreases due to interference from non-photoelectric conversion structures
Solution Approach 1:
The patent segments the on-chip lens into individual lenses for each pixel, rather than using a single common lens for multiple pixels. This segmentation eliminates the interference from charge transfer units and other non-photoelectric conversion structures that are positioned between the common lens and the photoelectric conversion units, thereby maintaining high light collection efficiency while achieving accurate phase difference detection.
2Reliability
If charge transfer units are arranged between pixels to transfer charges, then photoelectric conversion function is improved, but phase difference detection accuracy deteriorates due to errors introduced by these structures in common lens configuration
Solution Approach 1:
The patent extracts or removes the charge transfer units from the optical path between the on-chip lens and the photoelectric conversion units. By positioning the charge transfer units elsewhere or eliminating their interference in the light collection path, the patent maintains effective charge transfer functionality while preventing these structures from introducing errors into the phase difference detection process.
3Measurement precision
If individual on-chip lenses are arranged for each pixel, then phase difference detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the lens function at the pixel level, where each pixel has its own on-chip lens integrated directly with the photoelectric conversion unit. This integration approach, while providing individual lens control for accurate phase difference detection, is implemented through standard semiconductor manufacturing processes that combine multiple functions into a unified structure, thereby managing device complexity effectively.
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 reduces errors in phase difference detection by minimizing the impact of non-photoelectric conversion structures on light collection, enhancing the accuracy of phase difference detection.
Implementation Method 1
an on-chip lens arranged for each pixel and configured to individually collect the incident light; a common on-chip lens arranged in common for a plurality of phase difference pixels and configured to collect the incident light in common
Implementation Method 2
a photoelectric conversion unit configured to perform photoelectric conversion in accordance with incident light
Data Source
AI summary
An error is reduced in phase difference detection of an imaging element including a phase difference pixel with an on-chip lens in common for a pair of pixels. The imaging element includes a pixel, an individual on-chip lens, a plurality of phase difference pixels, a common on-chip lens, and a pixel circuit. The individual on-chip lens individually collects incident light for each pixel. The phase difference pixels are arranged adjacent to each other to detect a phase difference. The common on-chip lens is arranged in common for the plurality of phase difference pixels and collects incident light in common. The pixel circuit is formed in a semiconductor substrate and generates an image signal on the basis of a transferred charge. Charge transfer units of the plurality of phase difference pixels are in a region between the common on-chip lens and the individual on-chip lens.