Display Substrate Color Filter Layers for Uniform Illumination
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Solution Overview
Problem
In liquid crystal display (LCD) devices, misalignment between the lower and upper substrates can lead to a thickness difference between the display region and the peripheral region, causing a stripe line to form due to varying light transmittance, which degrades image display quality.
Innovation Solution
A display substrate is designed with a first color filter layer in the display region and a second color filter layer in the peripheral region, both formed on the lower substrate, to minimize thickness differences and ensure uniform light transmittance, thereby preventing stripe lines and enhancing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If color filters are formed only on the display region of the lower substrate, then the manufacturing process is simple, but the thickness difference between display region and peripheral region causes varying light transmittance and stripe lines
Solution Approach 1:
The patent applies local quality by forming color filter layers with different properties in different regions: the first color filter layer (RGB) is formed in the display region to enable color display, while the second color filter layer (yellow) is formed in the peripheral region to compensate for thickness differences. This regional differentiation resolves the contradiction by maintaining manufacturing simplicity while achieving uniform light transmittance across the entire substrate.
Solution Approach 2:
The patent changes the optical parameters of the color filter layers by selecting different color characteristics for different regions. The display region uses RGB color filters with specific transmission characteristics, while the peripheral region uses yellow color filters with different transmission properties. This parameter change allows the peripheral region to compensate for the thickness difference effect, achieving uniform overall light transmittance while maintaining the simple manufacturing process.
2Illumination intensity
If color filters are formed on both display and peripheral regions, then light transmittance uniformity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the formation of color filters in both regions into a single integrated manufacturing process. The first and second color filter layers are formed simultaneously or in sequence using the same coating and drying processes, eliminating the need for separate manufacturing steps. This merging approach achieves uniform light transmittance across display and peripheral regions while avoiding the complexity of multiple independent manufacturing processes.
3Manufacturing precision
If the lower substrate thickness is increased in the display region, then alignment with the upper substrate is improved, but light transmittance in the display region decreases
Solution Approach 1:
The patent introduces the second color filter layer (yellow) in the peripheral region as an intermediary element that compensates for the thickness difference between the lower and upper substrates. This intermediary layer adds optical path length in the peripheral region, effectively balancing the total thickness without requiring physical thickening of the substrate in the display region, thereby preserving light transmittance while achieving proper alignment.
Data Source
AI summary
A display substrate comprises a base substrate divided into a display region and a peripheral region surrounding the display region, wherein an image is displayed in the display region, a pixel part formed in the display region of the base substrate, a first color filter layer formed on the base substrate including the pixel part, wherein the first color filter layer is formed in the display region, and a second color filter layer formed in the peripheral region of the base substrate.