Display TFT Contact Structure for Light-Blocking Reliability
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Solution Overview
Problem
Display devices with increased thin-film transistor integration for precise light control face challenges in high power consumption and reliability, especially when light penetrates from an opening area to the display area, affecting the device's reliability.
Innovation Solution
A display device design featuring a substrate with an opening area surrounded by a display area and a non-display area, incorporating a first thin-film transistor with a silicon semiconductor and a second thin-film transistor with an oxide semiconductor, along with a light-blocking structure that includes conductive layers and contact holes to prevent light penetration and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of thin-film transistors is increased to accurately control light emission, then the precision of light control is improved, but the power consumption and device complexity increase
Solution Approach 1:
The pixel circuit is divided into multiple transistor units, each responsible for specific control functions. This segmentation allows precise control of light emission while organizing the complexity into manageable modular components, making the system more controllable and maintainable despite the increased number of transistors.
Solution Approach 2:
Multiple thin-film transistors are designed to perform different specialized functions (switching, storage, control) within the pixel circuit. This multi-functionality approach enables accurate light control through coordinated operation of specialized components, rather than using a single complex transistor.
2Adaptability or versatility
If more functions are added to the display device, then the versatility is improved, but the area occupied by the display device increases
Solution Approach 1:
Additional functional layers (organic insulating layers, conductive layers) are stacked in the vertical dimension rather than expanding horizontally. This allows multiple functions to be integrated within the same planar area by utilizing the third dimension, maintaining a compact display device while adding versatility.
Solution Approach 2:
Multiple functional elements are nested within each other, with conductive layers, insulating layers, and transistor structures arranged in concentric or nested configurations. This nesting allows multiple functions to coexist in a compact space, adding versatility without proportionally increasing the overall device area.
3Illumination intensity
If light penetrates from the opening area to the display area, then the brightness is improved, but the reliability of the thin-film transistor deteriorates
Solution Approach 1:
The first organic insulating layer acts as an intermediary protective barrier between the light source and the thin-film transistor. This layer allows necessary light transmission for display functionality while simultaneously protecting the transistor from direct light exposure that would cause deterioration, thus maintaining both brightness and reliability.
Solution Approach 2:
The harmful effect of light on the transistor is extracted and isolated by positioning the transistor structure such that the contact hole overlaps with the non-display area, separating the light path from the sensitive transistor components while maintaining display brightness through proper optical design.
Data Source
AI summary
A display device includes: a substrate including an opening area, a display area, and a non-display area arranged between the opening area and the display area; a first thin-film transistor arranged on the substrate and including a first semiconductor layer including a silicon semiconductor; a first insulating layer covering the first semiconductor layer and defining a lower contact hole overlapping the non-display area, a second thin-film transistor arranged on the first insulating layer and including a second semiconductor layer including an oxide semiconductor; a second insulating layer covering the second semiconductor layer and defining an upper contact hole overlapping the lower contact hole; a display element overlapping the display area, a lower conductive layer overlapping the lower contact hole; and an upper conductive layer arranged on the second insulating layer and connected to the lower conductive layer through the lower contact hole and the upper contact hole.