Mask Plate Transition Structure for Low-Slope Pixel Definition Layers
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Solution Overview
Problem
The existing manufacturing process for display substrates results in large slope angles of the pixel definition layer patterns, leading to color deviations and reduced encapsulation reliability, which affects the yield of the display device.
Innovation Solution
A mask plate with first transparent and opaque patterns and transition structures is used to expose the pixel definition layer, where the transition structures have line widths less than the exposure machine's resolution, allowing for a delicate transition formation and reduced slope angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mask plate with clear transparent and opaque patterns is used for exposure, then the pixel definition layer can be formed, but the slope angle becomes large causing color deviation and poor encapsulation reliability
Solution Approach 1:
The mask plate is segmented into three distinct pattern types: transparent patterns, transition structures (with sub-structures of different transparency), and opaque patterns. This segmentation allows gradual light intensity transitions instead of abrupt changes, reducing the slope angle of the pixel definition layer from conventional large angles to less than 20 degrees, thereby improving both manufacturing precision and encapsulation reliability
Solution Approach 2:
Different regions of the mask plate are assigned different local qualities: transparent patterns allow full light transmission, transition structures provide partial light transmission with varying degrees of transparency, and opaque patterns block light completely. This local quality differentiation creates a gradient effect that controls the slope angle locally at each pixel boundary, preventing color deviation and ensuring reliable encapsulation
2Manufacturing precision
If the slope angle of the pixel definition layer is large, then the pattern can be formed clearly, but color deviation occurs and organic rheological material cannot achieve plane flow
Solution Approach 1:
Transition structures serve as an intermediary between transparent and opaque patterns, providing intermediate light transmission levels. These transition structures with sub-structures of different transparency create a gradual light intensity gradient, which forms the pixel definition layer with small slope angles (less than 20 degrees), preventing color deviation while maintaining pattern clarity
Solution Approach 2:
The transparency parameter of the mask plate patterns is changed across different regions: transparent patterns have high transparency, transition structures have intermediate transparency with varying degrees, and opaque patterns have zero transparency. This parameter change creates a continuous light intensity gradient that controls the slope angle and prevents color deviation in the formed pattern
3Measurement precision
If the transition structures have line width greater than exposure machine resolution, then they can be clearly resolved, but the transition effect is insufficient and slope angle remains large
Solution Approach 1:
The transition structures are designed with line widths less than the exposure machine's resolution limit, making them unresolvable by the exposure system. This excessive fineness creates a blurred transition effect that is actually desirable, as it produces the gradual light intensity gradient needed to form pixel definition layers with slope angles less than 20 degrees, achieving superior slope angle control
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 approach reduces the slope angle of the pixel definition layer to less than 20°, preventing color deviations and ensuring easy plane flow of organic rheological materials, thereby improving the encapsulation reliability and yield of the display device.
Implementation Method 1
a layer of photosensitive pixel definition layer material is formed on the substrate, the pixel definition layer material is exposed by using a mask plate
Implementation Method 2
the transition structures include a plurality of second transparent patterns and second opaque patterns alternately arranged, and a line width of each of the second transparent patterns and each of the second opaque patterns is less than the resolution of an exposure machine by using the mask plate for exposure
Data Source
AI summary
A mask plate is used for manufacturing a pixel definition layer of the display substrate, which includes first transparent patterns and first opaque patterns, and further includes transition structures located between the first transparent patterns and the first opaque patterns. And the transition structures include a plurality of second transparent patterns and second opaque patterns alternately arranged, and a line width of each of the second transparent patterns and each of the second opaque patterns is less than the resolution of an exposure machine by using the mask plate for exposure.