Integrated Touch Screen Layout for Polarizer-Free OLED Displays
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Solution Overview
Problem
Organic light emitting display devices with integrated touch screens face issues such as increased thickness due to adhesive layers, reflection of external light by polarizers, and color mixture due to excessive distance between the organic light emitting layer and the black matrix, which narrows the luminance viewing angle.
Innovation Solution
A display device with integrated touch screen design that reduces the distance between the organic light emitting layer and the black matrix, eliminates the need for a polarizer by using a black matrix to prevent external light reflection, and includes a touch electrode structure that minimizes thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive layer is used to bond the lower substrate to the upper substrate, then the substrates are securely bonded, but the thickness of the display device is increased
Solution Approach 1:
The patent removes the adhesive layer from the structure by directly bonding the lower substrate to the upper substrate through a vacuum sealing process, eliminating the thickness contribution of the adhesive layer while maintaining bonding strength through atmospheric pressure sealing
Solution Approach 2:
The patent combines the bonding function and sealing function into a single vacuum sealing process, where the vacuum seal simultaneously bonds the substrates together and creates the encapsulated cavity, eliminating the need for a separate adhesive layer
2Object-affected harmful factors
If a polarizer is added to prevent external light reflection, then image visibility is improved, but the device thickness is increased and cost is increased
Solution Approach 1:
The patent converts the harmful reflection of external light by touch electrodes into a beneficial effect by using the black matrix to absorb both the emitted light from the organic light emitting device and the reflected external light, eliminating the need for a polarizer
Solution Approach 2:
The black matrix serves dual functions: it defines the pixel boundaries and acts as a light absorption layer to prevent both color mixture and external light reflection, replacing the need for separate polarizer components
3Adaptability or versatility
If the distance between the organic light emitting layer and the black matrix is increased to accommodate other layers, then more components can be integrated, but color mixture occurs and luminance viewing angle is narrowed
Solution Approach 1:
The patent rearranges the layer structure by placing the black matrix at the bottom of the encapsulated cavity closest to the organic light emitting device, and positioning touch electrodes on the opposite side of the upper substrate, effectively utilizing the vertical dimension to minimize the optical path distance while accommodating all necessary components
Solution Approach 2:
The patent introduces a reflective layer as an intermediary between the organic light emitting device and the black matrix to redirect emitted light toward the viewing direction and away from the black matrix, preventing color mixture while maintaining a compact structure
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 enhances image visibility in outdoor conditions, reduces thickness, and prevents color mixture while maintaining a wide luminance viewing angle without increasing cost.
Implementation Method 1
when a high-level voltage is applied to the anode electrode and a low-level voltage is applied to the cathode electrode, a hole and an electron move to the organic light emitting layer through the hole transporting layer and the electron transporting layer and are combined with each other in the organic light emitting layer to emit light
Implementation Method 2
a black matrix for dividing the color filters
Implementation Method 3
by using an adhesive layer, the lower substrate where the organic light emitting device is provided is bonded to the upper substrate where the color filters and the black matrix are provided
Data Source
AI summary
Disclosed is a display device with integrated touch screen, which prevents external light from being reflected by touch electrodes without a polarizer. The display device includes an organic light emitting device layer disposed on a substrate, a plurality of color filters disposed on the organic light emitting device layer, a plurality of first touch electrodes and a plurality of second touch electrodes disposed on the plurality of color filters to overlap a boundary portion between the plurality of color filters, and a black matrix disposed on the plurality of first touch electrodes and the plurality of second touch electrodes to overlap the plurality of first touch electrodes and the plurality of second touch electrodes.