OLED Subpixel Layout for Viewing Angle and Transistor Protection
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Solution Overview
Problem
In electro-optical devices using OLEDs, color shift occurs when subpixels are arranged in a transverse direction, leading to color mixing and reduced transistor characteristics due to light emission from adjacent subpixels, and increased scanning line selection time due to inefficient scanning line arrangement.
Innovation Solution
The electro-optical device incorporates conductive layers arranged in specific directions to prevent light from the light-emitting layer from reaching transistors, with wider reflective layers in the transverse direction to minimize color shift and narrower pixel circuit regions to reduce scanning line selection time, using overlapping conductive layers to block light and manage noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subpixels are arranged in a transverse direction to improve viewing angle characteristics, then color shift is reduced, but light from adjacent subpixels causes color mixing and transistor characteristic degradation
Solution Approach 1:
A light blocking layer is introduced as an intermediary element between adjacent subpixels to prevent light from one subpixel from reaching the transistor of an adjacent subpixel. This mediator blocks the harmful light while maintaining the transverse arrangement benefits for viewing angle characteristics.
Solution Approach 2:
The display structure is segmented into distinct functional regions: light emitting regions, light blocking regions, and transistor regions. By segmenting the pixel structure and strategically placing light blocking layers between subpixels, the patent prevents color mixing while maintaining transverse arrangement advantages.
2Device complexity
If scanning lines are arranged in the vertical direction to simplify the scanning structure, then device complexity is reduced, but the number of scanning lines increases and selection time for each scanning line decreases
Solution Approach 1:
The patent transitions from a vertical scanning line arrangement to a horizontal scanning line arrangement, changing the dimensional orientation of the scanning structure. This dimensional change reduces the number of scanning lines required and increases the selection time for each scanning line, while maintaining manageable device complexity.
3Reliability
If the reflective layer width in the transverse direction is reduced to improve transistor characteristics, then light application to transistors is reduced, but the area available for light emission and color filtering is reduced
Solution Approach 1:
The pixel structure is segmented into a light emitting area and a transistor area, with the light blocking layer creating a clear separation. This segmentation allows the reflective layer to be optimized for transistor protection without compromising the light emitting area, as the light blocking layer prevents light from reaching the transistor region.
Solution Approach 2:
The light blocking layer serves as a mediator that allows the reflective layer to be positioned closer to transistors for better protection, while the light blocking layer itself prevents light from reaching the transistor, thus maintaining both transistor characteristics and light emission area.
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 configuration effectively prevents color shift and maintains transistor characteristics, while reducing the selection time for scanning lines, ensuring stable and high-quality image display even when the device is viewed at an inclined angle.
Implementation Method 1
the third conductive layer of at least one subpixel has a width in the first direction, which is wider than a width in the second direction, and overlaps the fourth conductive layer and at least one transistor
Implementation Method 2
emitted light beams of the red color, the greed color, and the blue color are obtained through color filters of three primary colors
Data Source
AI summary
Subpixels of R, G, and B corresponding to a scanning line extended in a row direction and a data transfer line extended in a column direction are provided. A plurality of transistors in the subpixel of each of the colors is disposed along the column direction, and a reflective layer in the subpixel of at least one color is disposed along the row direction so as to overlap any transistor of subpixels of each display color. A power source wiring is disposed between the reflective layer and the transistor along the row direction, so as to overlap the transistor. Relay electrodes which connects the reflective layer and any transistor of subpixels of each display color are formed on a layer between a layer on which the power source wiring is formed, and the reflective layer.