LCD Touch Screen Contact Structure for High Aperture Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing LCD devices with built-in touch screens face a challenge in maintaining high aperture ratios due to the increased size of the contact portion between the common electrode and the gate metal, leading to reduced visibility and complex manufacturing processes.
Innovation Solution
The proposed solution involves a simplified contact structure where the gate metal and common electrode are electrically connected via a contact metal, with the gate metal positioned in the central portion of the pixel, and the common electrode formed inside a contact hole, allowing for an overlap configuration that enhances the aperture ratio while reducing the manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact portion size between common electrode and gate metal is increased to ensure electrical connection, then the electrical connectivity is improved, but the aperture ratio of the pixel is reduced and visibility is degraded
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar contact arrangement to a three-dimensional stacked configuration. The gate metal, contact metal, and common electrode are arranged in vertical layers rather than a single plane, allowing electrical connection without increasing the horizontal footprint. This vertical stacking enables the contact portion to be positioned in the central region of the pixel, preserving the aperture ratio while ensuring reliable electrical connectivity between the gate metal and common electrode.
2Reliability
If the contact structure is made more complex to ensure proper electrical connection, then the electrical connectivity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges multiple functions into the contact metal layer. The contact metal serves dual purposes: it provides electrical connection between the gate metal and common electrode, and simultaneously acts as part of the pixel electrode structure. This integration simplifies the manufacturing process by reducing the number of separate layers and steps required, while still ensuring reliable electrical connectivity. The unified contact metal structure eliminates the need for additional complex connection layers.
3Reliability
If the contact portion size is increased to improve electrical connection, then the electrical connectivity is improved, but the manufacturing precision requirements become more stringent
Solution Approach 1:
By moving the contact structure to the vertical dimension through layered stacking, the patent reduces the horizontal alignment precision requirements. Instead of requiring precise lateral alignment of large contact portions, the design allows for greater tolerance in the horizontal plane while maintaining reliable vertical electrical connections through the stacked gate metal, contact metal, and common electrode layers.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A liquid crystal display device with a built-in touch screen, which uses a common electrode as a touch-sensing electrode including an intersection of a gate line and a data line to define a pixel region, a gate metal disposed in a central portion of the pixel, an insulating layer formed on the gate metal, a first contact hole disposed through the insulating layer to expose a predetermined portion of an upper surface of the gate metal, a contact metal on the insulating layer and inside the first contact hole, the contact metal electrically connected with the gate metal, a first passivation layer on the contact metal, a second contact hole disposed through the first passivation layer to expose a predetermined portion of an upper surface of the contact metal, a common electrode on the first passivation layer and inside the second contact hole, a conductive line electrically connected with the common electrode, and a second passivation layer on the first passivation layer and the conductive line, wherein the gate metal and the common electrode are electrically connected via the contact metal.