Display Reflection Control Layer for Optical Fingerprint Sensing
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Solution Overview
Problem
Existing fingerprint recognition systems in multimedia electronic devices face challenges in blocking external light noise, which affects the sensitivity and reliability of fingerprint sensing using optical methods.
Innovation Solution
Incorporating a reflection control layer with specific dyes and an inorganic absorbing layer in the display element layer to improve transmittance for sensing light and reduce noise from external light, while maintaining sensitivity and reliability of the light receiving element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light receiving element is incorporated in the display area for fingerprint sensing, then fingerprint recognition function is enabled, but external light noise interferes with sensing accuracy
Solution Approach 1:
The patent applies local quality by implementing a reflection control layer with specific dye materials at particular locations (blue pixel region and green pixel region) around the light receiving element. Each dye is selectively positioned to absorb specific wavelength ranges of external light that would interfere with the light receiving element, while maintaining transparency to the sensing light wavelength. This localized application of light-absorbing materials with specific spectral properties resolves the contradiction by protecting the sensor from external light noise without compromising fingerprint sensing functionality.
Solution Approach 2:
The reflection control layer acts as an intermediary between the external environment and the light receiving element. The dye-containing layers serve as mediators that selectively absorb harmful external light wavelengths before they reach the sensor, while allowing the sensing light to pass through. This intermediary structure enables the light receiving element to function accurately without direct exposure to interfering external light, thus resolving the technical contradiction.
2Object-affected harmful factors
If a reflection control layer with dyes is added to reduce external light noise, then noise reduction is achieved, but light transmittance for sensing may be reduced
Solution Approach 1:
The patent employs parameter changes by carefully selecting dye materials with specific absorption spectral characteristics and controlling their concentration and layer thickness. The dyes are chosen to have maximum absorption in the blue (450-490nm) and green (530-570nm) regions while maintaining high transmittance in the sensing wavelength range. By adjusting these parameters—wavelength selectivity, concentration, and layer thickness—the system achieves effective noise reduction without compromising the transmittance of sensing light, thus resolving the contradiction between noise reduction and light transmittance.
3Measurement precision
If multiple dye layers are implemented for selective wavelength absorption, then noise filtering precision is improved, but device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the reflection control function into multiple specialized layers, each containing dyes with specific absorption characteristics. One layer targets blue wavelength noise (450-490nm) while another layer targets green wavelength noise (530-570nm). This segmented approach allows each layer to be optimized for a specific noise wavelength range, achieving high noise filtering precision. The segmentation strategy manages complexity by organizing the light filtering function into modular, functionally-distinct layers rather than requiring a single complex filtering system.
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 the sensitivity of the light receiving element by improving transmittance and reducing noise from external light, thereby improving the reliability of fingerprint recognition.
Implementation Method 1
a first dye having a maximum absorption wavelength within a range from about 420 nm to about 500 nm and a second dye having a maximum absorption wavelength within a range from about 560 nm to about 620 nm
Data Source
AI summary
An electronic device includes: a base layer; a display element layer on the base layer; and a reflection control layer on the display element layer and comprising a dye, the display element layer comprising: a pixel definition layer having first, second, and third openings formed therethrough; a first light emitting element corresponding to the first opening and emitting a first light; a second light emitting element corresponding to the second opening and emitting a second light different from the first light; a light receiving element corresponding to the third opening; and an inorganic absorbing layer on the first and second light emitting elements, and wherein the reflection control layer overlaps the first light emitting element and the second light emitting element.