Shield Conductor with Birefringent Structures for Touch Display Noise Reduction
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Solution Overview
Problem
Existing liquid crystal display devices with touch panel functions face accuracy issues in detecting contact position due to noise generated by the electric field from driving signals, requiring complex noise removal systems.
Innovation Solution
Incorporating a shield conductor with birefringent structures on the second substrate adjacent to the liquid crystal layer, which blocks the electric field and functions as a polarizer, preventing noise interference and improving contrast without thickening the substrate or using a complex system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex noise removal system is used to suppress electric field noise, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
A shield conductor is introduced as an intermediary component between the liquid crystal layer and the detection electrode. This shield conductor blocks the electric field generated by the liquid crystal driving signal, preventing it from reaching the detection electrode and causing noise. The shield conductor is connected to a reference potential to effectively ground the electric field interference, thereby improving detection accuracy without requiring complex noise removal systems.
Solution Approach 2:
The harmful electric field component is extracted and isolated from the detection path by using the shield conductor. The shield conductor specifically targets and removes the electric field noise generated by the liquid crystal driving signal, separating it from the detection electrode's measurement function. This allows the detection system to operate independently without complex noise cancellation mechanisms.
2Object-affected harmful factors
If the second substrate is thickened to accommodate noise shielding structures, then noise suppression is improved, but substrate thickness increases
Solution Approach 1:
The shield conductor is positioned locally at the critical interface between the liquid crystal layer and the detection electrode, specifically where the electric field noise is most problematic. Rather than uniformly thickening the entire substrate, the shielding function is concentrated in this specific local region, maintaining thin substrate overall while effectively suppressing noise at the source of interference.
3Measurement precision
If additional noise shielding components are added, then detection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The shield conductor is designed to serve multiple functions simultaneously: it acts as an electric field shield to block noise from reaching the detection electrode, and it also functions as a polarizer to improve the contrast of the liquid crystal display. By combining these two functions into a single component, the invention improves detection accuracy without adding additional manufacturing steps or components.
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
This configuration effectively suppresses noise interference, enhances detection accuracy, and improves contrast by reducing polarization state changes, while simplifying the manufacturing process and reducing heating risks.
Implementation Method 1
an electric field that is generated to be directed toward the second substrate is blocked by the shield conductor
Implementation Method 2
The shield conductor has a plurality of birefringent structures that are arranged in a stripe
Data Source
AI summary
An input-capable display device includes a first substrate a second substrate, a detection electrode, a dielectric film, and a detector. A pair of electrodes that drive a liquid crystal layer are provided on the first substrate. The second substrate is opposed to the first substrate through the liquid crystal layer. The detection electrode and the dielectric film are laminated on an outer surface of the second substrate. The detector detects a position at which an electrostatic capacitance is formed with the detection electrode through the dielectric film. The second substrate includes a shield conductor that is provided on a side adjacent to the liquid crystal layer. An electric potential of the shield conductor is fixed. The shield conductor has a plurality of birefringent structures that are arranged in a stripe.