Opposite-Polarity Photodiode Layout for High-Density Color Detection
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Solution Overview
Problem
Existing organic photodiodes (OPDs) face challenges in achieving high resolution detection due to the necessity of multiple types for different color sensitivities, which complicates pixel arrangement and density.
Innovation Solution
A detection device with a first and second photodiode coupled in series with opposite polarity, each sensitive to different wavelength ranges, and paired with specific light sources emitting in those ranges, allowing time-division detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple types of photodiodes are provided for different color sensitivities, then detection sensitivity for different wavelengths is improved, but device complexity and pixel arrangement difficulty increase
Solution Approach 1:
A single photodiode structure is designed to perform multiple detection functions by detecting different wavelength ranges through time-division control. The photodiode detects first wavelength range light during a first period and second wavelength range light during a second period, eliminating the need for separate photodiodes for different colors while maintaining multi-wavelength detection capability
Solution Approach 2:
The detection process is divided into periodic time intervals where the photodiode alternates between detecting different wavelength ranges. By controlling the light source and photodiode operation in periodic cycles (first period for first wavelength, second period for second wavelength), the system achieves spectral separation without spatial separation of multiple photodiode types
2Measurement precision
If multiple types of photodiodes are provided for different color sensitivities, then detection sensitivity for different wavelengths is improved, but manufacturing complexity increases
Solution Approach 1:
The invention uses a single type of photodiode structure that can be manufactured uniformly, eliminating the need to manufacture and assemble multiple different photodiode types for different colors. This universal photodiode design simplifies the manufacturing process while achieving multi-wavelength detection through temporal control
Solution Approach 2:
The detection wavelength is changed by controlling operational parameters (time periods and light source activation) rather than changing the physical photodiode structure. This allows the same photodiode to detect different wavelengths by adjusting control signals, simplifying manufacturing compared to producing multiple photodiode variants
3Measurement precision
If multiple types of photodiodes are provided for different color sensitivities, then detection sensitivity for different wavelengths is improved, but pixel arrangement density decreases
Solution Approach 1:
By making each photodiode universal and capable of detecting multiple wavelength ranges through time-division control, the invention eliminates the need for multiple photodiodes per pixel location. This reduces the area required for each pixel and increases overall arrangement density while maintaining full-color detection capability
Solution Approach 2:
The time-division detection approach allows a single photodiode to sequentially detect different wavelength ranges, effectively packing multiple detection functions into a single spatial location. This temporal multiplexing increases pixel density by removing the need for spatial multiplexing of multiple photodiode types
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
Enables high-resolution detection by efficiently utilizing photodiodes with opposite polarity configurations to capture multiple wavelength ranges, enhancing pixel density and detection sensitivity.
Implementation Method 1
a first photodiode sensitive to at least a first wavelength range; a second photodiode sensitive to a second wavelength range and a third wavelength range
Data Source
AI summary
According to an aspect, a detection device includes: a first photodiode sensitive to at least a first wavelength range; a second photodiode sensitive to a second wavelength range and a third wavelength range that are different from the first wavelength range; a first light source configured to emit light in the first wavelength range and light in the second wavelength range; and a second light source configured to emit at least light in the third wavelength range. The first photodiode and the second photodiode are coupled in series with opposite polarity.