Photoelectric Conversion Element With Segmented Pixel Arrays
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Solution Overview
Problem
Conventional photoelectric conversion elements struggle to handle a wide range of light intensities, from weak to high, due to the trade-off between light receiving area and dynamic range, limiting their ability to accurately detect light across varying intensities.
Innovation Solution
A photoelectric conversion element with two types of pixels, each with different light receiving areas and quenching resistor values, allows for selective output current extraction based on incident light intensity, enabling efficient detection across a wide range by adjusting the gain accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a photoelectric conversion element uses a single pixel type with fixed light receiving area, then the structure is simple, but it cannot accurately detect light across a wide intensity range from weak to high
Solution Approach 1:
The photoelectric conversion element is segmented into two distinct pixel types: first pixels with larger light receiving areas for weak light detection, and second pixels with smaller light receiving areas for high light intensity detection. This segmentation allows each pixel type to be optimized for specific light intensity ranges, resolving the contradiction between adaptability and structural simplicity.
Solution Approach 2:
Different regions of the photoelectric conversion element have different pixel characteristics. First pixels are designed with larger light receiving areas and higher gain characteristics suitable for weak light regions, while second pixels have smaller areas and lower gain for high intensity regions. This local quality differentiation enables accurate detection across the full light intensity range without requiring a complex adjustable structure.
2Measurement precision
If the light receiving area of pixels is increased to improve weak light detection, then photon detection efficiency increases, but saturation occurs at lower light intensities
Solution Approach 1:
The pixel array is divided into two functional segments: first pixels with larger light receiving areas optimized for weak light detection with high photon detection efficiency, and second pixels with smaller light receiving areas that prevent saturation at high light intensities. This segmentation resolves the trade-off between weak light sensitivity and high light intensity handling capability.
Solution Approach 2:
The light receiving area parameter is varied between two discrete values to create two pixel types. First pixels have a larger light receiving area parameter for high sensitivity, while second pixels have a smaller area parameter for high dynamic range. This parameter variation allows the system to maintain measurement precision across both weak and high light intensity conditions.
3Adaptability or versatility
If the light receiving area of pixels is decreased to increase dynamic range, then saturation is delayed, but photon detection efficiency for weak light decreases
Solution Approach 1:
The photoelectric conversion element is segmented into two pixel types with complementary characteristics: first pixels with larger light receiving areas for high photon detection efficiency in weak light conditions, and second pixels with smaller areas for extended dynamic range and delayed saturation. This segmentation allows the system to achieve both high dynamic range and accurate weak light detection simultaneously.
Solution Approach 2:
The photoelectric conversion element achieves multi-functionality by incorporating two pixel types that can handle different light intensity conditions. The first pixels provide universal weak light detection capability, while second pixels provide universal high light intensity handling capability. Together, they create a universal detector that handles the full light intensity range 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 solution allows for accurate detection of weak light intensities with high photon detection efficiency and high light intensities with low saturation, effectively expanding the manageable light intensity range without altering the pixel arrangement or operation voltage.
Implementation Method 1
each of which includes an avalanche photodiode
Implementation Method 2
avalanche photodiode (hereinafter referred to as an APD)
Data Source
AI summary
A photoelectric conversion element includes: a plurality of pixels that are formed on a common semiconductor substrate and each of which includes an avalanche photodiode; a first line that is formed on the semiconductor substrate, is electrically connected to two or more first pixels included in the plurality of pixels, and collectively extracts output currents from the two or more first pixels; and a second line that is formed on the semiconductor substrate, is electrically connected to two or more second pixels included in the plurality of pixels, and collectively extracts output currents from the two or more second pixels. A light receiving area of each first pixel is larger than a light receiving area of each second pixel.