Liquid Crystal Display Assembly Touch Detection Without Air Gap
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Solution Overview
Problem
Current touch panels are undesirably thick due to the need for an air gap to detect touch-induced changes in capacitance, which complicates their design and increases thickness.
Innovation Solution
A liquid crystal display assembly (LCDA) with a first and second glass layer separated by liquid crystals, where sensing devices with electrode groups are embedded between the layers, allowing touch detection without an air gap by varying the gap sizes between electrodes to differentiate force strengths, thereby reducing panel thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air gap is used to detect touch-induced changes in capacitance, then touch detection function is achieved, but panel thickness increases
Solution Approach 1:
The patent merges the force sensing function with the existing liquid crystal display structure by embedding electrode groups directly between the first and second glass layers. The sensing electrodes are integrated into the LCD assembly, eliminating the need for a separate air gap structure while achieving both touch detection and force sensing functions within the same compact structure.
Solution Approach 2:
The patent transitions from a one-dimensional air gap structure to a two-dimensional electrode group arrangement within the liquid crystal layer space. By positioning first and second electrodes facing each other across the liquid crystal layer, the sensing function is achieved in the plane of the display rather than requiring additional thickness in the vertical direction.
2Reliability
If an air gap structure is used for touch detection, then capacitance change detection is enabled, but device complexity increases
Solution Approach 1:
The liquid crystal layer serves multiple functions: it maintains the liquid crystal display function while simultaneously acting as the medium for force sensing. The same liquid crystal layer that enables display also enables touch and force detection when electrode groups are embedded, eliminating the need for separate air gap structures and reducing overall device complexity.
Solution Approach 2:
The liquid crystal display assembly itself provides the sensing function through its existing structure. By embedding electrodes within the liquid crystal layer, the display assembly becomes self-sufficient for both display and touch/force sensing functions, eliminating the need for additional dedicated sensing components or air gap structures.
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 LCDA effectively combines touch detection with force sensing, reducing panel thickness by eliminating the need for an air gap and enabling accurate determination of touch position and force strength through electrode contact and current flow.
Implementation Method 1
the capacitance of a capacitor is calculated using the formula: C=ε×S/(4πkd), where S is the area that the force sensor directly faces to the MF layer, k is the electrostatic constant (i.e., Coulomb's constant), ε is a relative dielectric constant, and d is the distance between the force sensor and the MF layer. According to the formula, when the distance d is changed, the capacitance C may also be changed.
Implementation Method 2
When the surface of the touch panel is pressed by applying a force, the distance between the force sensor and the GND may be changed. Further, the capacitance of a capacitor is calculated using the formula: C=ε×S/(4πkd)
Implementation Method 3
a second glass layer arranged with the first glass layer having liquid crystals filled there-between
Data Source
AI summary
A liquid crystal display module (LCDA) and electronic device are provided. The LCDA includes a first glass layer, and a second glass layer arranged with the first glass layer having liquid crystals filled there-between. The LCDA also includes at least one sensing device. Each sensing device includes at least one electrode group. Each electrode group is between the first glass layer and the second glass layer, and includes a first electrode bonded to the first glass layer and a second electrode bonded to the second glass layer. A gap separates the first electrode from the second electrode.