Liquid Crystal Display Light Shielding Layer Structure
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Solution Overview
Problem
In liquid crystal displays, the light shielding effect in the peripheral area is inadequate due to the optical density reduction of the light shielding layer when both the column spacer and light shielding layer are disposed on the transparent pixel electrode, leading to light leakage.
Innovation Solution
A method where a data insulating layer, color filter layer, and organic film layer are formed on a thin-film transistor substrate, with a light shielding layer and column spacer formed simultaneously, and the organic film material is selectively removed to enhance the light shielding effect in the peripheral area, ensuring the color filter layer's thickness is 1.0 um or less to prevent the data insulating layer from being etched, and a protrusion pattern is used to maintain the column spacer's height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both column spacer and light shielding layer are disposed on the transparent pixel electrode, then the cell gap is maintained and structural support is provided, but the optical density of the light shielding layer is reduced causing light leakage
Solution Approach 1:
The patent divides the light shielding layer into two distinct parts: a first light shielding layer in the display area and a second light shielding layer in the peripheral area. This segmentation allows each layer to be optimized independently - the first layer maintains appropriate optical density for display quality while the second layer provides enhanced light shielding in the peripheral area where the column spacer is located, thus resolving the contradiction between cell gap maintenance and light leakage prevention.
Solution Approach 2:
The patent applies different optical density characteristics to different regions of the light shielding layer. The first light shielding layer in the display area has optimized optical density for normal light shielding, while the second light shielding layer in the peripheral area is specifically designed with enhanced optical density to compensate for the light leakage caused by the column spacer structure. This local quality differentiation resolves the contradiction by addressing light leakage only where it occurs without affecting the overall display performance.
2Object-affected harmful factors
If organic film material is selectively removed to enhance light shielding effect, then light leakage is prevented, but the data insulating layer may be etched away
Solution Approach 1:
The patent introduces a color filter layer as a preliminary protective action before the light shielding layer is formed. This color filter layer serves as a sacrificial mask during the etching process to remove organic film material. By having this pre-formed protective layer in place, the etching process can selectively remove the organic film to enhance light shielding without directly exposing and etching away the data insulating layer, thus resolving the contradiction between light leakage prevention and insulating layer protection.
Solution Approach 2:
The color filter layer acts as an intermediary protective barrier between the etching process and the data insulating layer. During the selective removal of organic film material, the color filter layer absorbs the etching action, preventing it from reaching the data insulating layer. This intermediary layer enables the enhancement of light shielding effect through organic film removal while maintaining the integrity of the underlying data insulating layer.
3Reliability
If color filter layer thickness is increased to prevent data insulating layer etching, then protection is provided, but light shielding effect is reduced
Solution Approach 1:
The patent segments the protective function between two layers: the color filter layer provides protection during etching, while the second light shielding layer in the peripheral area provides enhanced light shielding. By dividing these functions across different layers, the color filter layer can be kept thin (maintaining light shielding) while still providing adequate protection during the etching process, as the primary light shielding enhancement comes from the second light shielding layer rather than increasing color filter thickness.
Solution Approach 2:
The patent creates a composite structure where the color filter layer and second light shielding layer work together in the peripheral area. The color filter layer provides the necessary protection during manufacturing processes, while the second light shielding layer, positioned above it, provides the enhanced light shielding effect. This composite arrangement allows both protection and light shielding to be achieved without requiring the color filter layer to be excessively thick.
Data Source
AI summary
A liquid crystal display includes a first insulating substrate, a data insulating layer disposed on a data wire of the first insulating substrate, and a color filter layer, an organic film layer, and a light shielding layer disposed on the data insulating layer. The organic film layer is positioned on the color filter layer, and the light shielding layer is positioned on the organic film layer in the screen display area. The color filter layer and the light shielding layer contact each other in the peripheral area.