Dual Photodiode Light Source Type Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing color sensors that perform complete spectral analysis are complex and expensive to produce due to their complexity.
Innovation Solution
A sensor unit comprising a first photodetector for the visible spectral range, a second photodetector for the infrared spectral range, a calculation unit to derive quotient and frequency results, and an evaluation unit to determine the dominant light source type, all integrated into a compact single circuit using silicon diodes and adjustable dielectric layers for sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete spectral analysis sensors are used, then measurement precision is improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent extracts only the essential spectral information needed for light source type determination by using two specifically designed photodiodes (visible and infrared ranges) instead of capturing the complete spectrum. This selective extraction approach maintains sufficient measurement precision for the intended application while dramatically reducing device complexity
Solution Approach 2:
The patent makes the sensor unit universal by integrating multiple functions into a compact design: the same two photodiodes serve both for visible light detection and infrared detection, and the evaluation unit handles multiple light source type classifications. This multi-functionality reduces overall device complexity while maintaining measurement capability
2Measurement precision
If complete spectral analysis sensors are used, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
By extracting only the critical spectral bands (visible and infrared) using simple photodiodes rather than complex spectral sensors, the patent dramatically reduces manufacturing cost while retaining sufficient precision for light source type determination
Solution Approach 2:
The patent employs inexpensive silicon photodiodes with simple dielectric layer filters instead of expensive spectral analysis sensors. These simple components are cost-effective and can be mass-produced, making the overall sensor unit economically viable
3Device complexity
If two photodiodes with different spectral ranges are used, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent applies local quality by optimizing each photodiode for its specific spectral range with tailored dielectric layer filters. The visible photodiode has filters optimized for visible light, while the infrared photodiode has filters optimized for infrared wavelengths. This localized optimization ensures high measurement precision for each band despite using only two photodiodes
Solution Approach 2:
The patent changes the spectral sensitivity parameters of the photodiodes by adjusting the dielectric layer structures. By modifying the number, thickness, and material composition of dielectric layers, the sensor achieves different spectral responses that are optimized for distinguishing various light source types with high accuracy
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 cost-effective production of sensors that can accurately determine the dominant light source type, aiding in light spectrum reconstruction and exposure optimization in photography, and correcting color representation in displays and projectors without the need for IR light filtering.
Implementation Method 1
at least one first photodetector (10) designed to detect electromagnetic radiation in the visible spectral range and to generate a first output signal (11)
Implementation Method 2
at least one second photodetector (20) designed to detect electromagnetic radiation in the infrared spectral range and to generate a second output signal (21)
Data Source
AI summary
The invention relates to a unit (1) for determining the dominant light source type in electromagnetic radiation (2) incident on the unit (1) and generated from a plurality of light sources of different types. The unit comprises at least one first photodiode (10) designed to detect electromagnetic radiation in the visible spectral range and to generate a first output signal (11). The unit comprises at least one second photodiode (20) designed to detect electromagnetic radiation in the infrared spectral range and to generate a second output signal (21). The unit comprises at least one calculation unit (30) designed to derive a quotient result (23) and a frequency result (13) from the first (11) and second (21) output signals. The frequency result (13) provides information about the presence or absence of signal components in a predetermined frequency range contained in the electromagnetic radiation. The unit comprises at least one evaluation unit (40) designed to derive the dominant light source type from the quotient result (23) and the frequency result (13).