In-Cell Touch OLED Display with Overcoating Layer
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Solution Overview
Problem
Conventional organic light emitting display devices with touch panels are thick, leading to reduced visibility and increased manufacturing costs, and are not foldable due to the use of multiple films and polarizers that increase thickness and stress when folded.
Innovation Solution
An organic light emitting display device with an in-cell type touch sensor integration, featuring a flexible substrate with an adhesive layer bonding the touch electrode layer to the organic light emitting element layer, an overcoating layer with uniform transmissivity, and a black dye dissolved in a heat-resistant polymer, reducing the number of films and thickness, allowing for a foldable and power-efficient device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a touch panel is installed as an add-on type or on-cell type, then touch functionality is achieved, but the overall thickness of the display device is increased
Solution Approach 1:
The patent merges the touch sensor electrode layer with the OLED structure by integrating the touch sensor into the same substrate where OLEDs are manufactured. This in-cell integration combines two previously separate functions (display and touch sensing) into a single unified structure, eliminating the need for separate touch panel layers and thereby reducing overall device thickness while maintaining full touch functionality.
2Ease of operation
If multiple films and polarizers are used to implement touch screen, then touch sensitivity is improved, but the thickness increases and visibility deteriorates
Solution Approach 1:
The touch sensor electrodes are integrated within the same substrate plane as the OLED structure, merging the touch sensing function with the display structure. This eliminates the need for separate touch screen films and polarizers that would otherwise be stacked on top of the display, thereby reducing thickness and improving visibility while maintaining touch sensitivity through the transparent electrode design.
Solution Approach 2:
The patent uses transparent or translucent electrode materials for the touch sensor that minimize light absorption and maintain high visibility. The electrode layer is designed with optical properties that allow light to pass through with minimal interference, effectively changing the optical characteristics from opaque/multilayer to transparent monolayer, thereby improving visibility while maintaining touch functionality.
3Ease of operation
If conventional touch panel structures are used, then touch functionality is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent integrates the touch sensor manufacturing process with the existing OLED manufacturing process, combining two separate manufacturing sequences into one unified process flow. This allows both the OLED structure and touch sensor electrodes to be fabricated simultaneously on the same substrate using compatible materials and processing techniques, thereby reducing manufacturing complexity and cost compared to separate assembly of touch panels and displays.
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 improves transmissivity and luminous efficiency, reduces power consumption, and enables a thinner, more cost-effective, and foldable display device by minimizing the number of films and integrating touch sensors, thus enhancing manufacturing efficiency and device flexibility.
Implementation Method 1
The organic light emitting diode includes an anode connected to a thin film transistor, an emission layer, and a cathode. Further, upon application of a voltage to the anode and the cathode, holes and electrons are recombined into excitons within the emission layer. As a result, the excitons transition to a ground state, to thus cause light to be emitted.
Implementation Method 2
an adhesive layer between the touch electrode layer of the first substrate and an organic light emitting element layer of the second substrate, and configured to bond the first substrate with the second substrate
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Provided is an organic light emitting display device. The organic light emitting display device includes: a first substrate (120b) including a black matrix on one surface, an overcoating layer (220) formed of a semi-permeable material and configured to equalize a thickness of an area where the black matrix is present to a thickness of an area where the black matrix is not present, and a touch electrode layer on the overcoating layer; and a second substrate (120a) including an organic light emitting element on one surface and bonded to the first substrate (120b) to face each other.