Integrated Touch Detection in Organic EL Display Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional organic electroluminescence (EL) display devices with integrated touch sensors require an additional process for forming a photo-diode, which complicates manufacturing and increases costs.
Innovation Solution
A display device structure that includes a matrix of light emitting and light receiving pixels, where the light emitting element is formed by stacking a pixel electrode, first organic layer, second organic layer, third organic layer, and opposing electrode, and the light receiving element is formed by stacking a first electrode, first organic layer, third organic layer, and second electrode, allowing for integrated touch detection without the need for a separate photo-diode formation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional touch sensor with photo-diode is integrated into the organic EL display device, then touch detection functionality is achieved, but the manufacturing process becomes more complex and costs increase
Solution Approach 1:
The patent merges the light receiving element structure with the light emitting element structure by using the same organic layers (first organic layer, third organic layer) and electrode arrangements. The light receiving pixel shares the first organic layer and third organic layer with the light emitting pixel, eliminating the need for separate photo-diode formation processes and reducing manufacturing complexity
Solution Approach 2:
The organic layers and electrode structures serve dual functions: they act as both light emitting components and light receiving components. The first organic layer and third organic layer function as both emission layers and detection layers, allowing the same structural elements to perform multiple functions without requiring additional specialized components
2Adaptability or versatility
If a separate photo-diode formation process is added to the manufacturing process, then touch sensor functionality is achieved, but production efficiency decreases and costs increase
Solution Approach 1:
The patent combines the formation of light emitting elements and light receiving elements into a single integrated manufacturing process. The same organic layers are deposited and patterned to serve both functions simultaneously, eliminating the need for separate photo-diode formation steps and maintaining high production efficiency
Solution Approach 2:
The organic layers are prepared and positioned in advance to serve dual purposes. The first organic layer and third organic layer are formed before the final electrode patterning, allowing them to function as both light emitting and light receiving components without requiring additional subsequent processing steps
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 structure enables the integration of touch detection functionality within the display device without adding complexity to the manufacturing process, reducing costs and improving efficiency.
Implementation Method 1
When electrons from the cathode and holes from the anode are injected into the light emitting layer, the electrons and holes recombine, light emitting molecules included in the light emitting layer are excited by surplus energy discharged by the recombination, and light is emitted by de-excitation.
Implementation Method 2
light which is scattered by the object is received by a photo-diode arranged on the interior of the organic EL display device and thereby detection of the touch position is performed
Data Source
AI summary
A display device includes a plurality of pixel electrodes including a first pixel electrode, a first electrode adjacent to the first pixel electrode and arranged separated from the first pixel electrode, a bank covering an edge part of the first pixel electrode, an end part of the first electrode, and a region between the first pixel electrode and the first electrode, a first organic layer arranged above the first pixel electrode, above the first electrode and above the bank, a second organic layer arranged above the first organic layer overlapping the first pixel electrode, a third organic layer arranged above the second organic layer, above the first organic layer overlapping the first electrode, and above the first organic layer overlapping the bank, an opposing electrode arranged above the third organic layer overlapping the first pixel electrode, and a second electrode arranged above the third organic layer overlapping the first electrode.