Scotopic SiPM Ambient Light Sensing for Sub-0.1 Lux Accuracy
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Solution Overview
Problem
Conventional ambient light sensors struggle to accurately measure ambient light levels below 0.1 lux, as their spectral response does not mimic the human eye's response in low-light conditions, leading to deteriorated measurement accuracy in dark environments.
Innovation Solution
An integrated semiconductor optoelectronic component with a silicon photomultiplier and a scotopic filter, designed to mimic the human eye's spectral response under low-light conditions, utilizing a stack of metallic and dielectric layers for enhanced light detection and readout electronics for signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional ambient light sensor is used, then it can reliably detect ambient light in the range of a few lux up to 10^5 lux, but it cannot accurately measure ambient light levels below 0.1 lux
Solution Approach 1:
The patent changes the spectral response parameter of the sensor by using a scotopic filter instead of a conventional photopic filter. This parameter change enables the sensor to accurately detect light levels down to 0.01 lux by matching the human eye's scotopic vision characteristics, resolving the measurement accuracy issue in low-light conditions
Solution Approach 2:
The patent employs a composite optical filter structure combining scotopic filtering materials with the silicon photomultiplier detector. This composite design creates a sensor system that integrates the spectral filtering properties of scotopic materials with the high sensitivity detection capabilities of the silicon photomultiplier, enabling accurate low-light measurement
2Adaptability or versatility
If the spectral response is made to mimic the human eye in daylight (photopic), then it works well for conventional ambient light levels, but it is not suitable for measuring ambient light levels in dark environments
Solution Approach 1:
The patent introduces dynamic adaptability by offering two filter options (photopic and scotopic) that can be selected based on environmental conditions. The sensor system can dynamically adapt its spectral response characteristics to match either daylight or low-light conditions, ensuring reliable detection across different illuminance levels
Solution Approach 2:
The patent creates a universal ambient light sensor platform that can function in both photopic and scotopic conditions. By providing optional filter configurations, the same basic sensor design achieves multi-functionality, serving both conventional daylight applications and low-light night-time applications
3Measurement precision
If a silicon photomultiplier is used, then single photon sensitivity and large gain are achieved, but device complexity increases
Solution Approach 1:
The patent replaces conventional photodetector structures with a silicon photomultiplier, which uses avalanche multiplication physics instead of simple photoelectric conversion. This substitution provides inherent signal amplification and single-photon sensitivity, achieving high measurement precision while the integrated nature of the SiPM keeps the overall device complexity manageable
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
The component achieves accurate measurement of ambient light levels down to individual photons, with single photon sensitivity and a wide dynamic operating range, enabling reliable operation in low-light conditions.
Implementation Method 1
an optical filter covering the active surface area of the silicon photomultiplier, the optical filter being adapted to selectively transmit light onto the active surface area as a function of wavelength
Implementation Method 2
a silicon photomultiplier configured to deliver an output signal indicative of the intensity of the light that irradiates the component
Data Source
AI summary
An integrated semiconductor optoelectronic component for sensing ambient light levels includes a silicon photomultiplier configured to deliver an output signal indicative of the intensity of the light that irradiates the component. The silicon photomultiplier has an active surface area for light detection. The component also includes an optical filter covering the active surface area of the silicon photomultiplier. The optical filter is adapted to selectively transmit light onto the active surface area as a function of wavelength. The optical filter is a scotopic filter and has a spectral transmission curve that mimics the spectral response of the human eye under low-light conditions. The component further includes readout electronics for processing the output signal of the silicon photomultiplier.