Touch Sensor Electrode Width Optimization for Blue Emission Hiding
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Solution Overview
Problem
Conventional touch sensors in display devices suffer from image quality deterioration and color shift issues due to changes in viewing angle, particularly affecting the recognition of blue emission layers which are harder to recognize than red and green.
Innovation Solution
A display device design featuring a touch sensor with detection electrodes of varying widths and distances from emission layers, positioned to minimize hiding of the blue emission layer, using a laminated structure of inorganic and organic layers for sealing and a mesh-type electrode configuration to reduce emission layer hiding and maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional touch sensor with uniform detection electrode is used, then the touch sensing function is provided, but image quality deteriorates and color shift occurs due to viewing angle changes
Solution Approach 1:
The detection electrode is designed with different widths at different positions: a first width in the red emission layer region, a second width in the green emission layer region, and a third width in the blue emission layer region. This local differentiation allows each region to be optimized for its specific emission characteristics, reducing color shift and improving image quality across different viewing angles
Solution Approach 2:
The detection electrode intentionally breaks symmetry by having asymmetric widths across different color regions. The electrode width varies systematically across the red, green, and blue emission layers, creating an asymmetric structure that compensates for the different viewing angle characteristics of each color, thereby reducing overall color shift
2Ease of operation
If the detection electrode is positioned closer to emission layers, then touch sensitivity improves, but the blue emission layer becomes harder to recognize due to hiding
Solution Approach 1:
The detection electrode width is locally optimized for each emission layer region. In the blue emission layer region, the electrode maintains a specific third width that balances proximity for sensitivity while preventing excessive hiding. This local optimization allows the electrode to be close enough for good touch sensitivity without completely blocking the blue light
Solution Approach 2:
The electrode width parameter is changed across different regions: the first width for red, second width for green, and third width for blue. By adjusting this geometric parameter differently in each region, the patent achieves optimal balance between touch sensitivity and light transmission, particularly for the blue emission layer which is more susceptible to hiding
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 solution effectively reduces the hiding phenomenon of the blue emission layer and minimizes luminance and color shift, thereby maintaining image quality and improving recognition of the blue emission layer.
Implementation Method 1
a capacitive type touch sensor includes a detection capacitor with a plurality of detection electrodes, detects a change in capacitance of the detection capacitor occurring when a conductor, e.g., a finger, approaches the touch sensor
Data Source
AI summary
A display device includes a substrate, a display unit on the substrate, the display unit including a first emission layer, a second emission layer, and a third emission layer having different emission colors, a sealing part covering and sealing the display unit, and a touch sensor on the sealing part, the touch sensor including a detection electrode adjacent to the first emission layer, the second emission layer, and the third emission layer, and the detection electrode maintaining different distances from each of the first emission layer, the second emission layer, and the third emission layer in a surface direction of the substrate.