Organic Light Emitting Element with PIN Photo Diode for Luminance Control
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Solution Overview
Problem
Conventional organic light emitting elements face issues with deteriorating film quality and light emission properties over time, leading to reduced luminance and contrast, especially due to the use of organic materials, and have inefficient light detection as the size and thickness of photo diodes decrease.
Innovation Solution
An organic light emitting element with a photo diode incorporating a high-concentration P doping region, a low-concentration P doping region, an intrinsic region, and a high-concentration N doping region, along with a controller to regulate light emission based on external light incidence, enhancing light detection efficiency by reflecting incident light onto the photo diode and using a parallel configuration of photo diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If photo diode size is reduced to enable smaller display devices, then device miniaturization is achieved, but light detection efficiency deteriorates
Solution Approach 1:
The patent applies composite material structure by creating a multi-layered photo diode with P-type semiconductor layer, N-type semiconductor layer, and intrinsic semiconductor layer forming a PIN junction. This composite structure enhances light detection efficiency through improved charge carrier separation and collection, allowing smaller photo diodes to maintain high detection efficiency in miniaturized display devices.
2Illumination intensity
If organic thin film layer is used for light emission, then self-light emission and excellent viewing properties are achieved, but film quality and light emission properties deteriorate with time
Solution Approach 1:
The patent implements a feedback mechanism where the photo diode detects the actual luminance output of the organic light emitting element and provides this information to a control circuit. The control circuit adjusts the drive current in real-time to compensate for aging effects and maintain constant luminance output, thereby resolving the deterioration issue over time.
Solution Approach 2:
The patent dynamically changes the electrical parameters (drive current, voltage) of the organic light emitting element based on feedback from the photo diode. By adjusting these parameters in response to detected luminance changes, the system compensates for temporal deterioration and maintains stable light emission properties.
3Ease of manufacture
If conventional photo diode structure is used, then manufacturing simplicity is maintained, but light detection efficiency is insufficient for miniaturized devices
Solution Approach 1:
The patent employs a composite semiconductor structure with P-type, N-type, and intrinsic layers forming a PIN photodiode. This composite material approach enhances light detection efficiency through improved internal quantum efficiency and charge carrier multiplication effects, while remaining compatible with standard semiconductor manufacturing processes for display devices.
Solution Approach 2:
The patent applies local quality enhancement by creating regions with different doping concentrations and material properties within the photo diode structure. The intrinsic layer provides high purity region for efficient light absorption, while doped regions provide charge carrier collection pathways, optimizing detection efficiency in the miniaturized structure.
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 maintains constant luminance by controlling voltage based on light detection, improves light detection efficiency, and extends the average lifetime of holes for increased current flow, effectively addressing the issues of reduced luminance and detection efficiency in smaller display devices.
Implementation Method 1
a photo diode formed on the substrate and having a semiconductor layer joined into a high-concentration P doping region, a low-concentration P doping region, an intrinsic region and a high-concentration N doping region
Implementation Method 2
an organic light emitting diode formed on a substrate, coupled to a transistor including a gate, a source and a drain, and including a first electrode, an organic thin film layer and a second electrode
Data Source
AI summary
An organic light emitting element includes an organic light emitting diode formed on a substrate, coupled to a transistor including a gate, a source and a drain and including a first electrode, an organic thin film layer and a second electrode; a photo diode formed on the substrate and having a semiconductor layer including a high-concentration P doping region, a low-concentration P doping region, an intrinsic region and a high-concentration N doping region; and a controller that controls luminance of light emitted from the organic light emitting diode, to a constant level by controlling a voltage applied to the first electrode and the second electrode according to the voltage outputted from the photo diode.