Liquid Crystal Display Seal Structure for Narrow Frame Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In liquid crystal display devices with narrow frames, the bonding strength between the alignment film and sealing material is compromised, leading to unreliable sealing and uneven gaps due to the difficulty in completely separating the alignment film from the sealing material, especially as the frame area decreases.
Innovation Solution
A structure is implemented where a wall-like alignment film stopper is formed on the counter substrate, coinciding with a columnar spacer, and a concave portion is created on the TFT substrate to prevent the sealing material from being blocked by the stopper, allowing uniform spreading and enhancing the reliability of the seal portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the alignment film is formed on the entire surface of the TFT substrate or counter substrate, then the display area is fully covered, but the bonding strength between the alignment film and sealing material is reduced
Solution Approach 1:
The alignment film is formed with different properties in different regions: in the display area, it provides alignment function, while in the seal portion, it has reduced bonding strength to prevent excessive adhesion to the sealing material. This local differentiation resolves the contradiction between full coverage and bonding strength.
2Area of stationary object
If the frame width is reduced to achieve narrow frame structure, then the display area increases, but the overlapping range between alignment film and sealing material becomes difficult to control
Solution Approach 1:
A protrusion is formed on the sealing material before the alignment film is deposited. This preliminary structural feature serves as a physical barrier that automatically limits the overlapping range of the alignment film, eliminating the need for precise control during the alignment film formation process and enabling narrow frame structures.
3Reliability
If a material with low compatibility is formed in the sealing material portion to prevent contact, then the alignment film and sealing material are separated, but the production cost increases
Solution Approach 1:
Instead of introducing a separate low-compatibility material layer, the invention extracts and utilizes the existing alignment film material itself, controlling its deposition through the protrusion structure. This eliminates the need for additional material layers and reduces production costs while achieving the desired separation effect.
Data Source
AI summary
A liquid crystal display device includes: a TFT substrate including a TFT, an organic passivation film formed to cover the TFT, and an alignment film; and a counter substrate including a spacer and an alignment film. The TFT substrate and the counter substrate are bonded with a sealing material in a seal portion, with a liquid crystal interposed between the two substrates. A wall-like structure is formed in the seal portion of the counter substrate, in a direction parallel to a side of the counter substrate. A concave portion of the organic passivation film is formed at a position corresponding to the wall-like structure of the TFT substrate, in a direction parallel to the side of the TFT substrate. With this structure, a gap between the wall-like structure and the TFT substrate is increased to facilitate the movement of the sealing material before curing, to form the sealing material uniformly.