OLED Collimator Light Absorbing Layers Reduce Crosstalk
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Solution Overview
Problem
Optical biometric identification apparatuses face issues with scattered light beams during image capturing, leading to poor image quality and identification results due to crosstalk problems, which existing improvements have not effectively resolved.
Innovation Solution
An image capturing apparatus is designed with an OLED display panel and a collimator featuring stacked collimating devices with transparent substrates and light absorbing layers, where the light absorbing layers absorb scattered light beams, and the configuration of light passing openings and substrate thicknesses are optimized to reduce crosstalk, ensuring effective light collimation and improved identification ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light beam is emitted to illuminate the fingerprint, then the sensor can receive reflected light for identification, but the light beam is scattered during transmission resulting in poor image quality
Solution Approach 1:
A collimator structure is introduced as an intermediary component between the light source and sensor. The collimator includes a transparent substrate with a light absorbing layer containing multiple light passing openings, which guides and restricts light transmission paths to prevent scattering while maintaining sufficient light reach to the sensor.
Solution Approach 2:
The light absorbing layer is selectively positioned within the transparent substrate at specific locations corresponding to the sensing areas. This local placement allows light to pass through designated openings while absorbing scattered light in other regions, creating localized light control zones that improve image quality without blocking necessary light paths.
2Measurement precision
If the collimator structure is added to reduce light scattering, then image quality improves, but the device complexity increases
Solution Approach 1:
The collimator is constructed using a composite structure combining a transparent substrate material with a light absorbing layer. This composite design integrates light guiding and light absorbing functions into a single component, reducing the need for separate elements and simplifying the overall device structure while maintaining effective light scattering prevention.
Solution Approach 2:
The light absorbing layer is configured with multiple light passing openings forming a porous-like structure within the transparent substrate. This arrangement allows light to pass through specific pathways while the surrounding absorbing material captures scattered light, achieving effective light control with a relatively simple geometric pattern rather than complex multi-component systems.
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 effectively reduces crosstalk, enhancing the image capturing apparatus's identification ability by minimizing the impact of scattered light, thereby improving the quality of captured images and identification results.
Implementation Method 1
The light absorbing layer includes a plurality of light passing openings, and the plurality of light passing openings exposes a plurality of sensing areas of the sensor. The plurality of light absorbing layers among the plurality of stacked collimating devices absorbs scattered light beams between the plurality of light absorbing layers
Data Source
AI summary
An image capturing apparatus including a sensor, an organic light emitting diode (OLED) display panel, and a collimator is provided. The OLED display panel is disposed on an image capturing side of the sensor. The collimator is disposed between the OLED display panel and the sensor. The collimator includes a plurality of collimating devices overlapped with each other. Each of the collimating devices includes a transparent substrate and a light absorbing layer disposed on the transparent substrate. The light absorbing layer includes a plurality of light passing openings, and the light passing openings expose sensing areas of the sensor.