Autofocus Pixel Layout With Selective Pupil Transmittance
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Solution Overview
Problem
Solid-state imaging devices with image plane phase difference detection pixels face challenges in achieving high autofocus performance while maintaining image quality, particularly due to poor pupil division performance at large defocus, which complicates auto-focus accuracy and image capture.
Innovation Solution
A light receiving element with a first pixel and a second pixel, both sharing on-chip lenses but with the second pixel having lower transmittance on the outer side of the pupil region, allowing for high autofocus performance by intentionally limiting light flux on the outer side of the pupil region using a light-shielding film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dead zone extends in a center direction of a pixel to enhance pupil division, then pupil division performance is improved, but image quality is deteriorated
Solution Approach 1:
The patent applies local quality by differentiating the functional characteristics of different pixel types within the same imaging device. First pixels are designed with high transmittance across the entire pupil region to maintain image quality, while second pixels have reduced transmittance on the outer side of the pupil region to enhance pupil division performance. This localized differentiation allows each pixel type to optimize its specific function without compromising the other.
2Measurement precision
If the extension of dead zone is intensified to improve pupil division, then pupil division effect is enhanced, but both imaging performance and pupil division performance cannot be achieved simultaneously
Solution Approach 1:
The patent segments the pixel array into two distinct types with different functional characteristics. First pixels are dedicated to image capture with full transmittance, while second pixels are specialized for pupil division with selective transmittance reduction on the outer side. This segmentation allows both imaging performance and pupil division performance to be optimized simultaneously without the trade-off that occurs when a single pixel type tries to fulfill both functions.
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 enables high autofocus performance while minimizing image quality degradation by predicting light amounts and correcting pixel signals based on focus information, effectively handling both in-focus and out-of-focus scenarios.
Implementation Method 1
a first pixel that includes a plurality of photoelectric conversion units configured to share a first on-chip lens, receive incident light from a pupil region of an optical system via the first on-chip lens, and perform photoelectric conversion
Data Source
AI summary
There is provided a light receiving element capable of obtaining a signal with high autofocus performance while suppressing image quality degradation, an imaging device, and a correction processing method. The light receiving element includes: a first pixel that includes a plurality of photoelectric conversion units configured to share a first on-chip lens, receive incident light from a pupil region of an optical system via the first on-chip lens, and perform photoelectric conversion; and a second pixel that includes a plurality of photoelectric conversion units configured to share a second on-chip lens, receive the incident light from the pupil region of the optical system via the second on-chip lens, and perform the photoelectric conversion. The second pixel has lower transmittance on an outer side of the pupil region in which the first pixel is capable of receiving light as compared with the transmittance of the pupil region.