Transparent Display Substrate Patterning to Reduce TFT UV Exposure
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Solution Overview
Problem
Existing transparent display devices face issues with ultraviolet ray exposure causing negative shifts in thin-film transistor threshold voltage, reduced transmittance, and difficulty in repairing defective pixels due to the use of UV-blocking films, which increase cost and complexity.
Innovation Solution
A display device with a substrate featuring patterned areas selectively formed to overlap thin-film transistors, reducing ultraviolet ray exposure and eliminating the need for a separate UV-blocking member, allowing pixel repair through the substrate without restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a UV ray-blocking film is placed on the bottom of the substrate, then the active layer is protected from ultraviolet rays, but the cost increases and transmittance decreases
Solution Approach 1:
The patent extracts the UV-blocking function from a separate film layer and integrates it into the substrate itself through selective patterning. The substrate is patterned to include UV-blocking regions that directly protect the active layer, eliminating the need for an additional UV-blocking film and reducing both cost and transmittance loss.
Solution Approach 2:
The patent merges the UV-blocking function with the substrate structure by forming patterned regions within the substrate material. This integration combines the substrate's structural role with the UV-protection function, eliminating the need for separate UV-blocking films and reducing overall device complexity.
2Object-affected harmful factors
If a light-blocking layer is placed under the active layer, then ultraviolet rays are blocked, but when the thin-film transistor size is small, there is insufficient space to form the light-blocking layer
Solution Approach 1:
The patent shifts the UV-blocking function from the vertical dimension (layer under active layer) to the horizontal dimension (patterned regions in substrate). By patterning the substrate at the same level as the active layer, sufficient UV protection is achieved without requiring vertical space that would conflict with small transistor dimensions.
Solution Approach 2:
The patent introduces patterned regions in the substrate as an intermediary structure between the incoming ultraviolet rays and the active layer. These patterned regions serve as the UV-blocking mechanism without requiring direct placement under the active layer, thus accommodating small transistor sizes.
3Object-affected harmful factors
If a UV ray-blocking film is disposed on the entire back surface, then ultraviolet protection is maximized, but the film must be removed for pixel repair, increasing repair complexity
Solution Approach 1:
The patent applies UV-blocking properties locally rather than uniformly across the entire substrate. Patterned regions are formed only in specific areas where UV protection is needed, leaving other areas of the substrate transparent and accessible for ultraviolet laser repair of defective pixels.
Solution Approach 2:
The patent segments the substrate into patterned UV-blocking regions and non-patterned transparent regions. This segmentation allows UV protection in specific areas while maintaining accessibility in other areas for repair operations, eliminating the need to remove a complete UV-blocking film.
4Object-affected harmful factors
If a UV ray-blocking film is used, then ultraviolet protection is provided, but additional components increase manufacturing cost
Solution Approach 1:
The patent merges the UV-blocking function with the substrate manufacturing process itself. By forming patterned regions within the substrate during substrate fabrication, the need for separate UV-blocking film materials and additional assembly steps is eliminated, reducing manufacturing cost.
Solution Approach 2:
The patent extracts the UV-blocking function from separate film components and integrates it into the substrate structure. This eliminates the need for additional UV-blocking film purchases and reduces the number of components that need to be sourced and assembled.
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
The solution effectively reduces threshold voltage shifts, maintains transmittance, and enables cost-effective pixel repair without additional UV-blocking components, simplifying material usage.
Implementation Method 1
a patterned area vertically overlapping the second thin-film transistor is formed in a lower surface of the substrate... effectively block ultraviolet rays
Data Source
AI summary
Disclosed is a display device in which irradiation of ultraviolet rays to an active layer of each of some of thin-film transistors is reduced due to a patterned area formed in a lower surface of a substrate and in an area overlapping each of some of the thin-film transistors. Thus, negative shift of a threshold voltage of the thin-film transistor is reduced.