Liquid Crystal Display Touch Sensor Crosstalk Reduction
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Solution Overview
Problem
Conventional liquid crystal display devices with embedded optical sensors suffer from crosstalk issues due to parasitic capacitance, which affects touch sensitivity and display quality, especially when optical sensors are positioned near data lines, leading to vertical and horizontal crosstalk and making it difficult to manufacture slim devices.
Innovation Solution
The solution involves rearranging the positions of read-out lines to separate them from neighboring data lines by at least one pixel region, and using separate storage lines for touch sensing, which reduces parasitic capacitance and crosstalk, allowing for improved touch sensitivity and display quality without increasing the device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are embedded in liquid crystal panels to enable touch sensing, then touch sensitivity is improved, but crosstalk between read-out lines and data lines increases due to parasitic capacitance
Solution Approach 1:
The patent divides the panel into multiple pixel regions and uses separate read-out lines for different pixel regions. By segmenting the read-out line connections and assigning dedicated read-out lines to specific pixel regions, the patent reduces parasitic capacitance coupling between adjacent data lines and read-out lines, thereby minimizing crosstalk while maintaining touch sensing capability.
Solution Approach 2:
The patent implements different line configurations for different pixel regions. Specifically, odd-numbered pixel regions use a first read-out line configuration while even-numbered pixel regions use a second read-out line configuration. This local differentiation optimizes the read-out line positioning to minimize proximity to data lines in each specific region, reducing parasitic capacitance locally where needed.
2Device complexity
If read-out lines are positioned adjacent to data lines for compact design, then device complexity is reduced, but parasitic capacitance increases causing vertical and horizontal crosstalk
Solution Approach 1:
The patent utilizes the vertical dimension by routing read-out lines through different pixel regions (odd and even regions) rather than simply placing them horizontally adjacent to data lines. This dimensional rearrangement increases the effective distance between read-out lines and data lines, reducing parasitic capacitance while maintaining a relatively simple overall line configuration.
3Length of stationary object
If optical sensors are integrated within the liquid crystal panel to reduce device thickness, then profile is improved, but manufacturing precision requirements increase due to embedded sensor integration
Solution Approach 1:
The patent combines the optical sensor integration with the existing liquid crystal panel manufacturing process. By merging the sensor integration step with the panel fabrication sequence and using the established pixel region and line configuration frameworks, the patent achieves slim profile without proportionally increasing manufacturing precision requirements.
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 minimizes crosstalk, maintains display quality, and enables the integration of optical sensors within the liquid crystal panel, facilitating the production of slim and efficient touch-sensitive liquid crystal display devices.
Implementation Method 1
a photo sensing transistor formed on the output switching transistor and the storage line
Data Source
AI summary
A liquid crystal display device having optical sensors, for sensing a touch, embedded in a liquid crystal panel to improve touch sensitivity is disclosed. The liquid crystal display device includes pixel regions spaced from each other on a first substrate, gate lines formed to separate the pixel regions in a first direction, driving voltage lines parallel to the gate lines, data lines formed between the pixel regions in a second direction intersecting the first direction, storage lines parallel to the driving voltage lines, read-out lines separated from neighboring data lines by one pixel region in the second direction, display transistors formed at intersections of the gate and data lines, pixel electrodes formed in the pixel regions, output switching transistors formed between the gate and read-out lines, capacitors formed between the output switching transistors and storage lines, and photo sensing transistors formed on the output switching transistors and storage lines.