Under-Screen Fingerprint Optical Structure Against Ambient Light
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Solution Overview
Problem
Ambient light interferes with under-screen fingerprint recognition modules in OLED display technology, leading to poor imaging or failure in acquiring fingerprint images.
Innovation Solution
An under-screen fingerprint recognition module with a base substrate and fingerprint recognition units featuring a photosensitive unit and an optical structure comprising a light-transmitting ring and hole, arranged to guide signal light at large angles while shielding ambient light, thereby improving recognition accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If ambient light enters the under-screen fingerprint recognition module, then the photosensitive unit can detect light, but the imaging quality deteriorates and fingerprint recognition fails
Solution Approach 1:
The patent applies local quality by creating different optical properties in different regions of the light-shielding layer. The light-transmitting hole provides a localized transmission path for signal light at specific angles, while the surrounding light-shielding regions block ambient light. This spatial differentiation of optical properties allows the photosensitive unit to selectively receive useful light while rejecting harmful ambient light, thereby maintaining imaging quality.
Solution Approach 2:
The light-shielding layer with light-transmitting hole and ring serves as an intermediary optical element between the ambient light environment and the photosensitive unit. This intermediary structure filters light based on angle and direction, allowing signal light from the fingerprint to pass through while blocking ambient light. The intermediary layer thus mediates the interaction between light and the photosensitive unit, enabling accurate fingerprint recognition despite ambient light presence.
2Measurement precision
If a light-shielding structure is added to block ambient light, then fingerprint recognition accuracy improves, but the device structure becomes more complex
Solution Approach 1:
The patent merges the light-shielding function with the existing module structure by integrating the light-shielding layer into the under-screen fingerprint recognition module assembly. The light-shielding layer is positioned between the display substrate and the photosensitive unit, combining multiple functions (light shielding, structural support, and optical guidance) into a single integrated component rather than adding separate independent elements, thus reducing overall structural complexity.
Solution Approach 2:
The patent addresses the complexity issue by transitioning from a two-dimensional planar structure to a three-dimensional layered structure. The light-shielding layer is arranged at a specific height above the photosensitive unit, creating vertical dimensionality. The light-transmitting hole and ring are positioned at different heights, forming a three-dimensional optical pathway that guides light while blocking ambient light, thereby achieving effective shielding without excessive horizontal complexity.
3Length of moving object
If the light-transmitting hole and ring are positioned closer to the photosensitive unit, then the optical path is shorter, but the shielding effectiveness against ambient light decreases
Solution Approach 1:
The patent employs asymmetry in the vertical positioning of the light-transmitting hole and ring relative to the photosensitive unit. The light-transmitting hole is positioned at a first height and the ring at a second height, creating an asymmetric three-dimensional configuration. This asymmetric arrangement optimizes the optical path for signal light while maintaining effective ambient light shielding, as the staggered positioning creates multiple filtering stages that are more effective than symmetric or planar arrangements.
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 optical structure effectively prevents ambient light interference, enhancing the accuracy of fingerprint recognition by guiding signal light towards the photosensitive unit while shielding ambient light, thus improving the imaging effect.
Implementation Method 1
Light emitted by the light-emitting diode reaches a finger, and is totally reflected by ridges and valleys of a fingerprint. The totally-reflected light carries information about the ridges and valleys of the fingerprint, and is finally detected by the under-screen fingerprint recognition module
Implementation Method 2
The optical structure includes a light-transmitting ring and a light-transmitting hole sequentially arranged in a direction away from the photosensitive unit. The light-transmitting ring is formed in a first light-shielding layer, the light-transmitting hole is formed in a second light-shielding layer
Data Source
AI summary
The present disclosure provides an under-screen fingerprint recognition module, a display assembly and a display device. The under-screen fingerprint recognition module includes a base substrate and a plurality of fingerprint recognition units arranged on the base substrate. Each fingerprint recognition unit includes a photosensitive unit and an optical structure arranged on a photosensitive surface of the photosensitive unit. The optical structure includes a light-transmitting ring and a light-transmitting hole sequentially arranged in a direction away from the photosensitive unit. An orthogonal projection of the light-transmitting ring onto the photosensitive unit is completely located on the photosensitive surface of the photosensitive unit, and an orthogonal projection of the light-transmitting hole onto the light-transmitting ring is located within an opaque region surrounded by the light-transmitting ring.