Light Sensor Arrangement for Accurate Luminous Flux Detection
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Solution Overview
Problem
Existing light sensors face challenges in accurately detecting visible light due to sensitivity beyond the visible spectrum, particularly in the infrared region, leading to inaccurate measures of luminous content, which affects the control of electronic displays under varying ambient light conditions.
Innovation Solution
A light sensor arrangement comprising two or more sensors and an extraction circuit that nonlinearly combines signals from sensors responsive to different wavelength ranges, using quantum efficiencies to characterize luminous flux, including a stacked photodiode sensor with an upper photodiode filtering ambient light and a lower photodiode detecting infrared light, to generate a predominantly visible light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single photodiode sensor is used to detect ambient light, then the device structure is simple, but the measurement precision is poor because the sensor responds to both visible and infrared light, leading to inaccurate luminous flux detection
Solution Approach 1:
The patent divides the detection function into multiple photodiode sensors, each responsible for detecting specific wavelength ranges (visible light and infrared light). By segmenting the detection task across multiple sensors with different spectral responses, the system achieves accurate luminous flux measurement while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent uses multiple photodiode sensors that can detect different types of light (visible and infrared). By making the sensor system multi-functional, it can simultaneously measure both visible luminous flux and infrared radiation, then use algorithms to extract accurate visible light information while compensating for infrared interference.
2Measurement precision
If multiple sensors with different wavelength responses are used, then the measurement precision improves, but the device complexity increases due to additional sensors and signal processing requirements
Solution Approach 1:
The patent introduces an intermediary processing layer that receives signals from multiple photodiodes and applies algorithms to extract visible luminous flux information. This intermediary processing stage acts as a mediator between the raw sensor data and the final measurement output, enabling accurate visible light detection while managing the complexity of multiple sensors through systematic signal combination.
3Ease of manufacture
If sensors with broad spectral sensitivity are used, then the device is easier to manufacture with fewer components, but the measurement precision deteriorates due to inability to distinguish visible light from infrared radiation
Solution Approach 1:
The patent changes the operational parameters of the sensor system by using multiple photodiodes with different spectral sensitivity characteristics. Instead of relying on a single sensor's broad response, the system exploits differences in quantum efficiency across wavelength ranges to separate visible and infrared contributions, achieving accurate luminous flux measurement while using commercially available photodiode components.
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 solution effectively isolates and accurately represents the luminous flux of visible light, improving the control of electronic displays by minimizing the impact of non-visible radiation, with accuracy exceeding 95% representation of visible light across a wide range of illumination conditions.
Implementation Method 1
an upper photodiode that filters ambient light and provides a signal in response to visible light in the ambient light
Implementation Method 2
a lower photodiode that is arranged below the upper photodiode to receive the filtered light and that provides a signal in response to infrared light in the filtered light
Data Source
AI summary
Ambient light is sensed for use in determining luminous flux. According to an example embodiment, ambient light is sensed using two light sensor arrangements that respectively respond differently to light of different relative wavelengths. The output of the sensors is nonlinearly combined to generate data indicative of the luminous flux. This luminous flux data is used to generate a control output for controlling an electronic display.