OLED Ambient Light Detection Without External Photocells
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Solution Overview
Problem
Conventional lighting systems using organic light emitting devices (OLEDs) face challenges in differentiating between emitted light and ambient light, requiring additional components like photocells, which increase complexity and cost, and struggle with material availability and product lifetime for widespread household and commercial use.
Innovation Solution
An OLED system that can dynamically detect ambient light by generating a voltage output and use this signal to control its own light emission levels, allowing for feedback-based adjustment of luminescence without the need for external light level detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photocell is added to detect ambient light, then light level detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The OLED is designed to perform multiple functions: it serves as both the light-emitting component and the ambient light sensor. By utilizing the photoconductive properties of the organic light emitting layer, the OLED can detect ambient light levels while maintaining its primary lighting function, thereby eliminating the need for a separate photocell and reducing overall device complexity
Solution Approach 2:
The patent merges the light emission function and light detection function into a single OLED component. The organic light emitting layer is positioned to detect ambient light while the device simultaneously performs illumination, combining what were previously separate functions (photocell for detection, lamp for emission) into one integrated unit
2Measurement precision
If a photocell is positioned away from the lamp, then ability to detect ambient light is improved, but positioning complexity increases
Solution Approach 1:
By integrating the detection function within the same physical component (OLED), the patent eliminates the positioning complexity inherent in separating the photocell from the lamp. The organic light emitting layer naturally detects ambient light without requiring separate spatial placement of detection and emission components
3Adaptability or versatility
If additional components are added to the lighting system, then functional capability is improved, but cost increases
Solution Approach 1:
The OLED is designed to perform multiple functions: it serves as both the light-emitting component and the ambient light sensor. By utilizing the photoconductive properties of the organic light emitting layer, the OLED can detect ambient light levels while maintaining its primary lighting function, thereby eliminating the need for a separate photocell and reducing overall device complexity
Solution Approach 2:
The OLED system is self-sufficient, using its own organic light emitting layer to perform detection functions without requiring external sensor components. The device monitors its own operational state and ambient conditions through the inherent photoconductive properties of its light emitting material
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 efficient and cost-effective monitoring and control of ambient light levels within the OLED system, reducing complexity and enhancing material utilization while maintaining effective light emission.
Implementation Method 1
The OLED can be configured to provide an output voltage signal associated with ambient light impinging on a surface of the OLED
Implementation Method 2
Electrons are directly injected into the organic light emitting layer from the cathode and holes are directly injected into the organic light emitting layer from the anode. The electrons and holes travel through the light emitting layer and recombine to form excited molecules. The excited molecules emit radiation (i.e. visible light or UV radiation) as they decay.
Data Source
AI summary
An apparatus and method of detecting ambient light in a lighting system is provided. An OLED may be used to emit light and detect ambient light in such a system. Detection can occur during a time interval when light is not emitted from the OLED. Feedback to control the emitted light level of the OLED can be based on the detected ambient light.