Liquid Crystal Pixel Wiring Layout for Aperture and Contact Reliability
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Solution Overview
Problem
Existing electro-optical devices face challenges in improving the aperture ratio and reliability of electrical connections at contact holes, particularly due to the recessed shield layer design and the use of single-layer conductor structures that are prone to etching and adhesion issues.
Innovation Solution
The electro-optical device incorporates a relay layer with a main body and a protruding portion, along with a first wiring line also having a main body and a protruding portion, both featuring a stacked structure with a light-reflective first layer and a second layer with lower light reflectance. This configuration enhances the aperture ratio and reliability of electrical connections while minimizing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a recessed shield layer design is used, then the aperture ratio can be improved, but it becomes difficult to secure space for disposing contact holes and wiring lines
Solution Approach 1:
The patent changes the spatial arrangement by making the relay layer protrude upward from the recessed shield layer, utilizing the vertical dimension to resolve the space conflict. This allows contact holes to be disposed on the protruding surface without requiring additional horizontal space, thus maintaining the improved aperture ratio while providing adequate space for electrical connections.
Solution Approach 2:
The protruding relay layer acts as an intermediary structure between the recessed shield layer and the pixel electrode. It provides a raised platform that facilitates the disposal of contact holes and wiring lines, mediating between the space constraints of the recessed design and the need for electrical connection space.
2Ease of manufacture
If a single-layer conductor structure is used for contact holes, then the manufacturing process is simplified, but aluminum is more likely to be etched and adhesion deteriorates
Solution Approach 1:
The patent employs a composite conductor structure consisting of multiple layers (aluminum layer and titanium nitride layer) instead of a single-layer aluminum structure. The aluminum layer provides good electrical conductivity, while the titanium nitride layer offers etching resistance and adhesion improvement, thus enhancing reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The patent changes the material parameters by introducing a second layer (titanium nitride) with different properties than the first layer (aluminum). This composite structure modifies the overall characteristics of the contact hole conductor, providing both etching resistance and adhesion while maintaining electrical conductivity.
3Reliability
If a stacking structure with titanium nitride is used for contact holes and shield layer, then electrical connection reliability is improved, but heat is more likely to be generated due to high light absorption
Solution Approach 1:
The patent applies the stacking structure with titanium nitride selectively only in the contact hole regions where electrical connection reliability is critical, rather than throughout the entire shield layer. This localized application maintains the reliability benefits while minimizing the heat generation that would occur if the light-absorbing titanium nitride were present across the full area.
Solution Approach 2:
The patent modifies the spatial distribution parameter of the titanium nitride layer, confining it to specific contact hole regions rather than extending it across the entire shield layer. This parameter change reduces the total light absorption and corresponding heat generation while preserving the electrical connection reliability where it is most needed.
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 improves the aperture ratio and reliability of electrical connections at contact holes, while also reducing heat generation within the substrate, thereby enhancing the overall performance of the electro-optical device.
Implementation Method 1
both featuring a stacked structure with a light-reflective first layer and a second layer with lower light reflectance
Implementation Method 2
heat is more likely to be generated within the substrate due to an electrolytic-corrosion preventing layer made of titanium nitride or the like having high efficiency of light absorption
Data Source
AI summary
A liquid crystal device includes: a TFT; a pixel electrode; a first capacitance element; a third relay electrode extending along an X-axis and including a main body portion electrically connected to the TFT through a first contact hole and also including a protruding portion protruding from the main body portion in a +Y direction and electrically connected to the pixel electrode through a second contact hole; and a common wiring line including a main body portion extending along a Y-axis and also including a protruding portion protruding from the main body portion in a −X direction and electrically connected to the first capacitance element through a third contact hole. The third relay electrode and the common wiring line each includes a first layer, and a second layer having lower light reflectance. The second layer is not provided in a portion of the main body portion of the common wiring line.