OLED Touch Screen Shield Layer for Light Interference
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Solution Overview
Problem
Existing OLED touch screens face issues with low detection accuracy due to pressure-dependent signal intensity in resistance film methods and interference from internal light in light-based methods, which can damage the OLED panel and affect functionality.
Innovation Solution
The implementation of shield layers, such as black matrices made from metal insulator hybrid layers, black polymers, or carbon black, to prevent internal light interference, combined with photo sensors and touch electrodes made of transparent conductive materials like ITO, IZO, or AZO, arranged in a matrix format to enhance detection accuracy and protect the OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistance film method is used for the touch screen, then the touch screen can detect user input, but the detection accuracy is low because the signal intensity varies with applied pressure
Solution Approach 1:
The patent replaces the resistance film method (mechanical pressure-based detection) with a light-based detection method using photo sensors. The photo sensors detect user input through light interaction rather than mechanical pressure, eliminating the problem of pressure-dependent signal intensity and improving both detection accuracy and signal stability.
Solution Approach 2:
The patent introduces light as an intermediary medium between the user input and the photo sensors. The light interacts with the user's finger or pen on the touch screen surface and carries information to the photo sensors, enabling accurate detection without direct mechanical contact and improving measurement precision.
2Measurement precision
If a light method is used for the touch screen, then high detection accuracy is achieved, but the OLED panel may be damaged by internal light interference
Solution Approach 1:
The patent segments the touch screen structure by introducing a separate light-guiding layer that is spatially distinct from the OLED panel. This layer guides external light to the photo sensors while preventing internal light from the OLEDs from reaching the sensors, thereby isolating the detection function from the light emission function and eliminating interference.
Solution Approach 2:
The patent introduces a light-guiding layer as an intermediary structure between the OLED panel and the photo sensors. This layer selectively guides external light to the sensors while blocking internal light, acting as a mediator that enables accurate detection without transmitting harmful internal light to the photo sensors.
3Ease of operation
If a touch screen is added to the OLED display, then direct data input is enabled, but the press load may damage the OLED panel
Solution Approach 1:
The patent introduces a light-guiding layer as a protective intermediary structure between the touch screen surface and the OLED panel. This layer absorbs or distributes the press load from user input, preventing direct transmission of mechanical stress to the fragile OLED panel while still enabling light-based detection of user input.
Solution Approach 2:
The patent replaces mechanical pressure-based detection with light-based detection, eliminating the need for direct mechanical contact between the user input and the OLED panel. The photo sensors detect user input through light interaction, substituting mechanical stress with optical detection and thereby protecting the OLED panel from damage.
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 solution improves detection accuracy and reduces the risk of OLED panel damage by shielding internal light, allowing for a high-sensitivity touch screen operation while maintaining the self-luminance and low power consumption benefits of OLED displays.
Implementation Method 1
a plurality of shield layers between the OLEDs and the second substrate; and a plurality of photo sensors, each of the photo sensors being covered by a corresponding one of the shield layers
Implementation Method 2
a photo sensor is provided to detect variation of incident light and generate a corresponding electric signal, and a location is detected on the basis of the electric signal
Implementation Method 3
light is emitted by energy that is generated when an exciton generated by coupling of electrons and holes falls from an exited state to a ground state within the organic emission layer
Data Source
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AI summary
An OLED display including a first substrate on which a plurality of OLEDs are formed, a second substrate attached to the first substrate, a plurality of photo sensors formed on the second substrate and for detecting incident light generated by an external source, and a shield layer covering the photo sensor and for blocking (or preventing) light emitted from the OLED from being detected by the photo sensor.