LCD Pedestal Sinking Prevention via Composite Electrode Structure
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Solution Overview
Problem
In liquid crystal display devices, maintaining a consistent distance between the TFT substrate and the counter substrate is challenging, especially when organic films are formed on the TFT substrate, as pedestals can sink due to pressure from support columns, leading to display irregularities and reduced image quality.
Innovation Solution
A transparent electrode with a metal film is arranged below the pedestals on the TFT substrate, dispersing pressure and preventing sinking, while also forming common electrode auxiliary lines to maintain the distance between the substrates effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pedestals are formed on organic films on the TFT substrate, then the distance between substrates can be maintained, but the pedestals sink due to pressure from support columns causing display irregularities
Solution Approach 1:
The patent uses a composite structure combining transparent electrode material and metal film material to form pedestals. The transparent electrode provides mechanical support to prevent sinking, while the metal film maintains the required distance and provides electrical functionality. This composite approach resolves the contradiction by combining the advantages of both materials to achieve both distance maintenance and image quality stability.
Solution Approach 2:
The patent introduces a vertical stacking dimension by placing the transparent electrode below the metal film in the pedestal structure. This multi-layer vertical arrangement allows the transparent electrode to bear the mechanical load from support columns while the metal film maintains the critical distance, preventing the pedestal from sinking and maintaining image quality.
2Reliability
If the area of pedestals is decreased to suppress display irregularities, then image quality deteriorates, but if the area is increased, then the pedestals are more prone to sinking
Solution Approach 1:
By creating a composite pedestal structure with transparent electrode and metal film layers, the patent achieves both small pedestal area (for image quality) and effective load distribution (for distance maintenance). The transparent electrode layer provides the necessary mechanical strength to support the metal film pedestal at minimal area without sinking.
Solution Approach 2:
The patent employs a multi-layered vertical structure that distributes pressure through the thickness dimension rather than increasing horizontal area. The stacked layers of transparent electrode and metal film create a compact vertical profile that maintains pedestal area while effectively managing mechanical stresses.
3Manufacturing precision
If support columns are formed on the counter substrate, then the distance between substrates is maintained, but the support columns may slip on the TFT substrate surface
Solution Approach 1:
The patent introduces pedestals as intermediary structures formed on the TFT substrate surface. These pedestals serve as stable anchors for the support columns, preventing direct contact and potential slipping between the support columns and the TFT substrate. The pedestals provide a reliable interface that maintains both distance and position stability.
Solution Approach 2:
The pedestals are formed in advance on the TFT substrate before the support columns are positioned. This preliminary formation of pedestals creates predetermined anchor points that guide and stabilize the support columns, preventing them from slipping during the assembly process and ensuring long-term position stability.
Data Source
AI summary
A liquid crystal display device includes a TFT substrate and a counter substrate with liquid crystal sandwiched therebetween. Support columns which project toward the TFT substrate are formed on the counter substrate. A plurality of gate signal lines, a plurality of drain signal lines, thin film transistors, an insulation film which covers the thin film transistors, organic films which are arranged on the insulation film, and a transparent electrode which constitutes a common electrode arranged on an upper layer of the organic films, are formed on the TFT substrate. A metal film which constitutes a common electrode auxiliary line is arranged on an upper layer of the transparent electrode. The insulation film, the organic films, the transparent electrode, and the metal film are laminated in this order on the gate signal lines, and portions of the metal film arranged on the transparent electrode form pedestals corresponding to the support columns.