Optical Sensor Device for OLED Brightness Compensation
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Solution Overview
Problem
Existing display technologies face challenges in real-time optical compensation for OLED devices due to variations in brightness caused by aging, as conventional electrical compensation methods cannot address these issues effectively, and the integration of photo diodes for optical compensation leads to increased leakage current and performance degradation due to wet etching processes.
Innovation Solution
An optical sensor device is designed with a PIN type photo diode integrated in a specific structure, where the photo-sensitive device is placed in a groove formed by a through-hole, protected by the source and drain layers, and a passivation layer, which reduces the impact of ambient light and subsequent etching damage, enabling real-time optical compensation and improved display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photo diode is added for real-time optical compensation, then brightness variation compensation capability is improved, but leakage current increases and performance degrades
Solution Approach 1:
The photo diode is segmented into distinct functional layers (P-type layer, I-type layer, N-type layer) with specific material compositions and structures. This segmentation allows optimization of each layer's properties to reduce leakage current while maintaining optical detection capability. The layered structure enables better control of charge carrier generation and recombination, directly addressing the leakage current issue.
Solution Approach 2:
Different regions of the photo diode are assigned different material properties and structural characteristics. The P-type layer uses organic hole transport materials, the I-type layer uses intrinsic or lightly-doped materials, and the N-type layer uses organic electron transport materials. This local quality differentiation optimizes charge transport in each region while minimizing overall leakage current, resolving the contradiction between detection capability and performance degradation.
2Productivity
If wet etching process is used for TFT fabrication, then manufacturing efficiency is improved, but photo diode sidewall is damaged
Solution Approach 1:
The photo diode structure is designed with preliminary protective features that prevent damage from subsequent wet etching processes. The organic semiconductor layers and encapsulation structures are selected and configured to be resistant to common etchants used in TFT fabrication. This preliminary anti-action allows the use of efficient wet etching while protecting the photo diode sidewalls from damage.
Solution Approach 2:
The photo diode employs composite material structures combining organic semiconductors with encapsulation layers that provide chemical resistance. This composite approach maintains manufacturing efficiency through wet etching while protecting the photo-sensitive device from sidewall damage, resolving the contradiction between productivity and object protection.
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
This solution allows for real-time optical compensation, reducing display Mura caused by brightness variations and enhancing the overall display effect by protecting the photo-sensitive device from ambient light and etching damage, thus improving the performance and longevity of OLED displays.
Implementation Method 1
a PD (photo diode, e.g., a PIN type photo diode) is added in an organic light-emitting diode (OLED) display device, which is used for monitor the variation in the brightness of EL in a real-time manner
Data Source
AI summary
An optical sensor device, a method for fabricating the same, and a display device are disclosed. The optical sensor device includes a display region and a non-display region. In the display non-display region, the optical sensor device includes a thin film transistor, including an active layer, a gate insulating layer, a gate layer, a source and drain layer, and an interlayer dielectric layer. In the non-display display region, the optical sensor device includes a first insulating layer, a conductive layer and a second insulating layer which are stacked sequentially. The conductive layer is arranged in a same layer as the source and drain layer or the gate layer. In the non-display display region, the first insulating layer is provided with a first through-hole, and the optical sensor device further includes a photo-sensitive device in the first through-hole.