Embedded Touch Sensor Common Electrode for LCD Weight Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid crystal display devices with integrated touch sensors face challenges in weight and thickness reduction, as well as increased manufacturing costs due to the separate fabrication and attachment of touch panels, which affect mobility and design.
Innovation Solution
A liquid crystal display device with embedded touch sensors, where a common electrode is used for both data recording and touch sensing, forming a sensing capacitor between the touch sensor and the object, utilizing a thin film transistor array to drive the liquid crystal layer and output sensing signals, and a method for fabricating this device that integrates touch sensor components with the liquid crystal display structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate touch panel is manufactured and attached to the display device, then the touch input function is enabled, but the overall thickness and weight of the system increase
Solution Approach 1:
The patent combines the touch sensor functionality with the liquid crystal display device by integrating the touch sensor into the lower substrate of the LCD structure. The common electrode of the LCD serves dual purposes: as a display electrode and as a sensing electrode for touch detection, eliminating the need for a separate touch panel attachment.
Solution Approach 2:
The common electrode in the liquid crystal display device is designed to perform multiple functions: it serves as a display electrode for liquid crystal control and simultaneously as a sensing electrode for capacitive touch detection. This multi-functionality reduces the overall component count and system weight.
2Ease of operation
If a separate touch panel is manufactured and attached to the display device, then the touch input function is enabled, but the overall thickness of the system increases
Solution Approach 1:
The patent merges the touch sensor structure with the liquid crystal display structure by forming the touch sensor within the lower substrate of the LCD. The sensing capacitor is formed between the common electrode (in the lower substrate) and the upper substrate, eliminating the need for additional thickness from a separate touch panel attachment.
Solution Approach 2:
The touch sensor functionality is nested within the existing liquid crystal display structure. The sensing capacitor is formed using the space between the lower substrate (containing the common electrode) and the upper substrate, effectively utilizing the existing structural volume without adding external thickness.
3Ease of operation
If a separate touch panel is manufactured and attached to the display device, then the touch input function is enabled, but manufacturing costs increase
Solution Approach 1:
The patent combines the manufacturing processes of the liquid crystal display device and the touch sensor into a single integrated fabrication process. Both the display electrodes and the sensing electrodes are formed on the lower substrate using the same thin film transistor and electrode deposition techniques, eliminating the need for separate touch panel manufacturing and attachment operations.
Solution Approach 2:
The common electrode structure serves dual purposes in both display and touch sensing functions, allowing a single manufacturing process to produce both functionalities. The same electrode deposition and patterning processes used for LCD manufacturing are utilized to create the touch sensing electrodes, reducing overall manufacturing complexity and cost.
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 approach reduces the weight and thickness of the device, simplifies the manufacturing process, and enables multi-touch sensing while maintaining image quality by separating data recording and touch sensing periods.
Implementation Method 1
the touch sensors, each of which forms a sensing capacitor between an object touching the upper substrate and the common electrode to sense touch
Implementation Method 2
each of the plurality of pixels including a pixel electrode and a common electrode applying a horizontal electric field to the liquid crystal layer
Data Source
AI summary
Disclosed is a liquid crystal display device having touch sensors embedded therein. The liquid crystal display device includes a liquid crystal layer interposed between upper and lower substrates, pixels, each of which includes pixel and common electrodes applying a horizontal electric field to the liquid crystal layer, a pixel thin film transistor to drive the pixel electrode, and a common thin film transistor to drive the common electrode, touch sensors, each of which forms a sensing capacitor between an object and the common electrode, sensor power lines, readout lines, and sensor gate lines. Each touch sensor includes the common electrode, a first sensor thin film transistor charging the common electrode with the sensing driving voltage in response to control of the previous sensor gate line, and a second sensor thin film transistor outputting the sensing signal to the readout line in response to control of the current sensor gate line.