OLED Sub-pixel Symmetry and Layer Merging for Mask Alignment
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Solution Overview
Problem
Conventional OLED display devices face challenges in achieving high image quality due to limitations in manufacturing fine pitch masks, leading to inaccurate alignment and patterning of light emitting layers, which results in reduced display properties and image quality.
Innovation Solution
The OLED display device is designed with sub-pixels arranged such that the color arrangement of each pixel is symmetrical to its neighbors, allowing for the formation of light emitting layers as units, facilitating easier deposition and alignment using masks with larger opening portions, thereby improving precision and reducing the impact of sub-pixel size on mask pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between opening portions of the mask is reduced to achieve high resolution, then the image quality is improved, but the manufacturing precision and alignment accuracy of the mask deteriorate
Solution Approach 1:
The patent merges the deposition of light emitting layers for multiple sub-pixels (specifically red and green sub-pixels) into a single deposition process using a common opening portion in the mask. This reduces the number of mask openings required, thereby increasing the distance between remaining openings and improving mask manufacturing and alignment precision while maintaining high display resolution
Solution Approach 2:
The mask opening portions are designed to serve multiple functions by depositing light emitting layers for different sub-pixels (red and green) through the same opening. This multi-functional approach reduces the overall pitch requirements for the mask while ensuring accurate pattern formation for high resolution displays
2Measurement precision
If the sub-pixel size is reduced to achieve high resolution, then the image quality is improved, but the ease of manufacture deteriorates due to difficulties in patterning and aligning smaller features
Solution Approach 1:
The patent combines the light emitting layer deposition for red and green sub-pixels into a single process step using a shared mask opening. This merging approach effectively doubles the feature size for mask patterning purposes while maintaining the fine pitch sub-pixel structure in the final display, thereby improving ease of manufacture without sacrificing resolution
Solution Approach 2:
The patent segments the light emitting layers into different color components (red, green, blue) and deposits them in a specific sequence through a strategically designed mask pattern. By segmenting the deposition process and using larger opening portions for multiple colors, the mask manufacturing becomes easier while still achieving high resolution through precise layer sequencing
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 arrangement enables accurate and precise deposition of light emitting layers, enhancing the image quality of OLED display devices by reducing the effect of sub-pixel size on mask pitch and improving manufacturing ease, resulting in high-resolution displays.
Implementation Method 1
a mask with opening portions having the same patterns as the patterns of a film to be deposited is used. The mask may be closely adhered to a surface where the film is to be formed, and a material may be deposited on the surface through the mask to form a thin film having predetermined patterns
Data Source
AI summary
An OLED display device includes a plurality of pixels including sub-pixels arranged along a first direction, the sub-pixels being arranged in an order emitting red, green, and blue lights along the first direction or in a reverse order, wherein an arrangement of colors of light emitted from sub-pixels of one pixel is symmetrical to an arrangement of colors of light emitted from sub-pixels of an adjacent pixel, and wherein a light emitting layer of the sub-pixel emitting red light includes a light emitting layer emitting red light and a light emitting layer emitting green light, a light emitting layer of the sub-pixel emitting green light includes a light emitting layer emitting green light, and a light emitting layer of the sub-pixel emitting blue light includes a light emitting layer emitting blue light and a light emitting layer emitting green light.