OLED Collimator Lens for Fingerprint Sensor Shading
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Solution Overview
Problem
The integration of POL-less structure with optical fingerprint recognition technology in OLED display devices results in low recognition efficiency due to the shading effect of the black matrix, which blocks reflected light from the finger.
Innovation Solution
An OLED display device with a flexible substrate, a fingerprint recognition sensor, a thin-film encapsulation layer including a collimator lens structure, and a color filter layer is designed. The collimator lens structure, which can be a convex lens, Fresnel lens, or microlens array, is positioned above the fingerprint recognition sensor to converge reflected light effectively, and the color filter layer is formed using an inkjet printing process to reduce thickness and enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a black matrix is used in the color filter layer to define pixel regions, then color purity and pixel definition are improved, but the black matrix shades the reflected light from the fingerprint, reducing fingerprint recognition efficiency
Solution Approach 1:
The black matrix is segmented into two parts: a first black matrix layer that defines pixel regions and a second black matrix layer with light transmission holes positioned above the fingerprint sensor. This segmentation allows different regions of the black matrix to serve different functions - color definition and light transmission for fingerprint recognition
Solution Approach 2:
Light transmission holes are extracted from the black matrix structure, creating openings that allow reflected light from the fingerprint to pass through to the sensor while maintaining the pixel-defining function of the black matrix in other regions
2Object-affected harmful factors
If a polarizer is used to reduce reflectivity under light illumination, then glare is reduced, but nearly 58% of emitted light is lost, increasing power consumption and reducing service life
Solution Approach 1:
An anti-reflective coating is introduced as an intermediary layer between the OLED light-emitting functional layer and the color filter layer. This coating reduces reflectivity and glare without the light-blocking properties of a polarizer, maintaining light transmission while reducing harmful reflections
Solution Approach 2:
The patent replaces the traditional polarizer with alternative structures including anti-reflective coatings and modified black matrix designs that are thinner and less light-blocking. These alternatives achieve the glare-reduction function with minimal impact on light transmission and device flexibility
3Object-affected harmful factors
If a traditional polarizer is used in the OLED display, then reflectivity is reduced, but the thick and brittle material is not conducive to dynamic bendable products
Solution Approach 1:
The patent replaces the traditional thick polarizer with thin-film alternatives including anti-reflective coatings and modified black matrix structures. These thin-film solutions maintain the glare-reduction function while enabling device flexibility and bendability required for dynamic products
Solution Approach 2:
The invention uses thin-film encapsulation layers and thin-film black matrix structures that are flexible by nature. These thin films can accommodate bending and dynamic movements, enabling the OLED display to be used in flexible and wearable applications
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 configuration reduces the overall thickness of the OLED display device while significantly improving the recognition efficiency and accuracy of the fingerprint recognition sensor by ensuring that reflected light is directed towards the sensor, reducing shading effects and enhancing signal-to-noise ratio.
Implementation Method 1
A collimator lens structure is embedded in the first via-hole, the collimator lens structure is configured to allow the reflected light reflected by the fingerprint converged on different directions and allow the reflected light reflected in a vertical direction converged on the fingerprint recognition sensor
Data Source
AI summary
An organic light-emitting diode (OLED) display device and a manufacturing method thereof are provided. The OLED display device includes a flexible substrate, a fingerprint recognition sensor, a thin film transistor (TFT) array layer, an OLED light-emitting functional layer, a color filter layer, and a thin-film encapsulation layer. An outermost layer of the thin-film encapsulation layer is provided with a first via-hole. A collimator lens structure is embedded in the first via-hole, the collimator lens structure is configured to allow reflected light reflected by a fingerprint converged on different directions and allow the reflected light reflected in a vertical direction converged on the on the fingerprint recognition sensor.