CMOS Photodetector Microlens Layout for Pixel Sensitivity Uniformity
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Solution Overview
Problem
The existing technology using a single on-chip micro lens shared by multiple pixels of the same color in solid-state image pickup devices often fails to achieve sufficient performance, leading to reduced sensitivity in certain pixel sections.
Innovation Solution
A photodetector design that includes multiple pixels with photoelectric conversion regions and on-chip micro lenses, where a first and second on-chip micro lens are disposed in at least part of the pixel section, including n×n pixels, to enhance performance by reducing sensitivity gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single on-chip micro lens is shared by multiple pixels of the same color, then device complexity is reduced, but sensitivity uniformity deteriorates
Solution Approach 1:
The patent divides the pixel array into multiple blocks, where each block contains a group of pixels of the same color. Within each block, a single on-chip micro lens is shared by multiple pixels, creating a segmented lens distribution pattern. This segmentation approach balances complexity reduction with sensitivity uniformity by ensuring that no single pixel is disadvantaged while still achieving overall device simplification.
Solution Approach 2:
The patent implements different lens configurations for different regions of the pixel array. Specifically, certain pixels within a block share a common micro lens, while other pixels have dedicated or differently configured lenses. This local differentiation ensures that sensitivity requirements are met in critical areas while maintaining overall system simplicity.
2Ease of manufacture
If a single on-chip micro lens is shared by multiple pixels, then manufacturing cost is reduced, but image capture performance deteriorates
Solution Approach 1:
By organizing pixels into blocks with shared lenses, the patent reduces the total number of micro lenses required, directly lowering manufacturing complexity and cost. The segmentation ensures that performance is maintained through strategic grouping rather than uniform distribution.
Solution Approach 2:
The shared on-chip micro lens serves multiple pixels simultaneously, making a single optical element perform multiple functions. This multi-functionality reduces the total component count and manufacturing steps while the patent ensures performance requirements are met through careful block configuration.
3Reliability
If additional on-chip micro lenses are disposed in pixel sections, then sensitivity uniformity is improved, but device complexity increases
Solution Approach 1:
The patent introduces additional micro lenses in a segmented manner, adding them only in specific blocks or regions where sensitivity uniformity requires enhancement. This selective addition avoids uniformly increasing complexity across the entire device while targeting specific performance gaps.
Solution Approach 2:
Additional on-chip micro lenses are strategically placed in specific pixel sections or blocks where sensitivity uniformity needs improvement, rather than adding lenses uniformly across all pixels. This localized enhancement maintains sensitivity uniformity in critical areas while minimizing overall device complexity increase.
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 effectively suppresses sensitivity reduction in gap portions and enhances overall performance by strategically placing additional on-chip micro lenses in areas without the primary lens, improving image capture capabilities.
Implementation Method 1
an on-chip micro lens disposed for the pixels
Implementation Method 2
multiple pixels each having a photoelectric conversion region
Data Source
AI summary
The present disclosure relates to a photodetector and an electronic apparatus that can enhance their performance. Provided is a photodetector including multiple pixels each having a photoelectric conversion region, and an on-chip micro lens disposed for the pixels. In at least a part of a pixel section including n×n pixels, a first on-chip micro lens and a second on-chip micro lens different from the first on-chip micro lens are disposed. The present disclosure can be applied to CMOS solid-state image pickup devices, for example.