Organic Light Emitting Display Photo Diode Brightness Control
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Solution Overview
Problem
Conventional organic light emitting devices suffer from reduced lifespan due to deterioration of the organic material, leading to inconsistent brightness and image quality over time, and existing photo diodes have limited light receiving rates and control over brightness.
Innovation Solution
An organic light emitting display device incorporating a photo diode in a non-pixel region with a specific buffer layer thickness and channel width configuration, enhancing quantum efficiency to 50% to 90% for red wavelength light, allowing for effective control of brightness through electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a photo diode is added to control brightness, then brightness control capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the photo diode with the buffer layer structure, integrating the light receiving function into the existing device architecture. The photo diode is formed in the non-pixel region using the buffer layer as part of its structure, merging multiple functions into a unified design that controls brightness without proportionally increasing complexity
Solution Approach 2:
The buffer layer serves as an intermediary structure that supports both the organic light emitting device and the photo diode. By using the buffer layer as a common foundation and electrical connection path, the patent reduces the need for separate support structures, thereby controlling overall device complexity while enabling brightness control functionality
2Reliability
If buffer layer thickness is increased to improve photo diode performance, then quantum efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies an optimized thickness range for the buffer layer (2900 Å to 3100 Å) that balances quantum efficiency improvement with manufacturing feasibility. This parameter optimization ensures sufficient light absorption and photoelectric conversion while remaining within controllable manufacturing tolerances for existing fabrication processes
Solution Approach 2:
Instead of making the buffer layer extremely thick to maximize light absorption, the patent uses a moderate thickness increase (2900-3100 Å) that provides sufficient quantum efficiency improvement without excessive manufacturing difficulty. This partial action approach achieves adequate performance while maintaining manufacturing precision
3Reliability
If channel width of photo diode is increased to improve light receiving rate, then light receiving rate is improved, but device area increases
Solution Approach 1:
The patent positions the photo diode in the non-pixel region of the display device, utilizing space that would otherwise be unused. By concentrating the photo diode's light receiving function in this specific local area with optimized channel width, the patent improves light receiving rate without increasing the area of the pixel regions that display images
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 brightness and extends the lifespan of the organic light emitting device by effectively converting light energy into electrical signals, ensuring stable image quality and improved pixel opening rates.
Implementation Method 1
the photo diode to convert light energy received by (or incident on) the photo diode into an electric signal
Data Source
AI summary
An organic light emitting display device including: a substrate having a pixel region and a non-pixel region; a first buffer layer and a second buffer layer formed over the substrate; a thin film transistor formed over the second buffer layer; an organic light emitting device formed in the pixel region and electrically connected with the thin film transistor; and a photo diode formed in the non-pixel region, for receiving external light of red wavelength at a certain absorption rate, and for controlling brightness of the organic light emitting device. Here, the first buffer layer can be formed to be from 2900 Å to 3100 Å in thickness, the second buffer layer can be formed to be from 200 Å to 400 Å in thickness, and the photo diode can include: an N-type doping region, a channel region being from 3 to 10 μm in width, and a P-type doping region.