LCD Touch Sensing via Common Electrode Shielding
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Solution Overview
Problem
Existing LCD devices with touch screens require an additional touch screen on the upper surface, increasing thickness, manufacturing complexity, and cost.
Innovation Solution
Integrating a sensing electrode within the liquid crystal panel, using a substrate with gate and data lines, common electrodes, sensing lines, and an electric field shield layer to sense user touch without an additional touch screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an additional touch screen is formed on the upper surface of the liquid crystal panel, then a user's touch can be sensed, but the entire thickness is increased and the manufacturing process becomes complicated
Solution Approach 1:
The patent combines the touch sensing function with the existing liquid crystal panel structure by integrating sensing electrodes into the panel itself. The first and second sensing electrodes are formed within the liquid crystal panel structure, merging the display and touch sensing functions into a single integrated component, thereby eliminating the need for a separate additional touch screen layer.
Solution Approach 2:
The liquid crystal panel is designed to serve multiple functions: it acts as both the display medium and the touch sensing mechanism. The sensing electrodes are incorporated within the panel structure, allowing the same component to perform both image display and touch detection, thus reducing overall device complexity.
2Ease of operation
If an additional touch screen is formed on the upper surface of the liquid crystal panel, then a user's touch can be sensed, but the manufacturing cost is increased
Solution Approach 1:
By merging the touch sensing electrodes into the existing liquid crystal panel structure, the patent eliminates the need for separate touch screen components and assembly processes. This integration reduces material costs and manufacturing steps, thereby lowering the overall manufacturing cost while maintaining touch sensing functionality.
Solution Approach 2:
The multi-functional design allows the liquid crystal panel to serve as both display and touch sensor, reducing the total component count and assembly complexity. This universality leads to lower manufacturing costs by consolidating functions into a single product rather than requiring multiple separate components.
3Length of stationary object
If the common electrode is used as sensing electrode, then device thickness is reduced, but crosstalk between adjacent common electrodes may occur
Solution Approach 1:
The patent introduces a shielding structure positioned between adjacent common electrodes to act as an electromagnetic shield. This intermediary element blocks unwanted electric field interactions, preventing crosstalk between adjacent sensing regions while allowing the common electrode to serve dual purposes as both display and sensing element.
Solution Approach 2:
The shielding structure is strategically positioned only in specific regions between adjacent common electrodes where crosstalk occurs, rather than uniformly across the entire device. This localized approach provides targeted protection against crosstalk while minimizing impact on overall device performance and maintaining the thickness reduction benefit.
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
Reduces device thickness, simplifies manufacturing, and lowers costs while preventing crosstalk and light leakage by using the common electrode as both a sensing and electric field driver.
Implementation Method 1
According to whether or not an electric field is applied, an alignment of the liquid crystal layer is controlled so that light transmittance is controlled in the LCD device
Implementation Method 2
an alignment of the liquid crystal layer is controlled so that light transmittance is controlled in the LCD device
Implementation Method 3
if the user touches a predetermined portion, capacitance between the first and second sensing electrodes 24 and 26 is changed at the touched portion
Data Source
AI summary
A liquid crystal display device includes a substrate; gate and data lines disposed on the substrate crossing each other to define a plurality of pixel regions; a plurality of pixel electrodes disposed in the pixel regions; a common electrode which is patterned to have common electrode pattern portions, each common electrode pattern portion corresponding to a respective pixel region; a plurality of sensing lines disposed on the common electrode and electrically connected with the common electrode; and at least one an electric field shield layer disposed over a region between adjacent common electrode pattern portions.