Electromagnetic Touch Sensor Integrated into LCD Substrates
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Solution Overview
Problem
Existing EM type touch panels for LCD devices are thick and heavy due to the placement of the sensor unit below the backlight, which affects transmittance and requires additional shielding, complicating the manufacturing process and increasing device thickness.
Innovation Solution
Integrating an EM sensor with transparent coil arrays onto the substrates or polarizing plates of the LCD panel, allowing the EM sensor to be formed during the LCD panel manufacturing process, thus eliminating the need for additional shielding and reducing thickness by positioning the coils on the viewing area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor unit is positioned below the backlight, then the EM type touch panel can detect touched point location, but the device becomes thick and heavy and requires additional shielding
Solution Approach 1:
The patent inverts the conventional arrangement by positioning the EM sensor unit above the display surface rather than below the backlight. The sensor unit includes coil arrays that generate electromagnetic fields from the front side, allowing touched point detection without requiring the sensor to be positioned behind the backlight, thereby reducing device thickness and eliminating the need for additional shielding structures.
2Reliability
If the sensor unit is positioned below the backlight, then the EM type touch panel can detect touched point location, but transmittance is affected
Solution Approach 1:
By inverting the sensor unit position to above the display surface, the patent eliminates the shielding requirements that would otherwise block light paths. The coil arrays are positioned to generate electromagnetic fields without interfering with light transmission, thereby maintaining high transmittance while preserving touch detection functionality.
3Reliability
If the sensor unit is positioned below the backlight, then the EM type touch panel can detect touched point location, but the manufacturing process becomes complicated
Solution Approach 1:
The patent simplifies the manufacturing process by positioning the sensor unit above the display surface, which allows for more straightforward integration with the display assembly. The coil arrays can be directly formed on the substrate without requiring complex shielding structures and assembly steps, thereby reducing manufacturing complexity while maintaining detection reliability.
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 results in a thinner, lighter LCD device with improved transmittance and a simplified manufacturing process, as the EM sensor is integrated within the LCD panel, enhancing integration and reducing assembly complexity.
Implementation Method 1
the array coils to which the A.C. signal is applied generate a magnetic field. Then, the resonant circuit of the stylus pen generates a resonant frequency in response to the magnetic field
Implementation Method 2
the resonant frequency is detected in a controller of the touch panel, and the two-dimensional location of the touched point on the flat substrate is determined through a comparison process
Implementation Method 3
the resonant circuit of the stylus pen generates a resonant frequency in response to the magnetic field
Data Source
AI summary
An LCD device having an electromagnetic (EM) type touch panel is disclosed, which includes an electromagnetic sensor inside an LCD panel. The EM type touch panel has a thin profile and can be fabricated through a simplified manufacturing process. The LCD device includes an LCD panel having first and second substrates facing each other, and a liquid crystal layer between the first and second substrates; an EM sensor having X-axis and Y-axis transparent electrode coils formed in one body with any one of the first and second substrates in the LCD panel; a backlight unit below the LCD panel; and a controller below the backlight, the controller controlling the EM sensor.