Display Panel Fingerprint Recognition via Backlight Reflection
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Solution Overview
Problem
Existing display panels have low sensitivity in fingerprint detection due to small amounts of sensing signals received, resulting in low accuracy.
Innovation Solution
A display panel design that includes an array substrate with a fingerprint recognition region on the substrate, a photoelectric sensing device, and a backlight module, where light from the backlight module passes through the recognition region, allowing direct reflection from the finger to the sensing device, reducing light loss and increasing signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light passes through multiple layers to reach the photoelectric sensing device, then the sensing signal is attenuated, but adding light shielding layers to block ambient light reduces the useful light reaching the sensor
Solution Approach 1:
The patent applies local quality by making the light shielding layer selectively transparent: it shields ambient light from reaching the photoelectric sensing device while allowing backlight to pass through the fingerprint recognition region. This is achieved by positioning the light shielding layer to cover the sensor area specifically, creating localized light control that blocks harmful ambient light while preserving useful backlight transmission for fingerprint detection.
Solution Approach 2:
The backlight module serves as an intermediary light source that provides controlled illumination through the fingerprint recognition region. By introducing this dedicated light source that passes through the recognized region to illuminate fingerprints directly onto the sensor, the system mediates between the need for ambient light blocking and the need for sufficient sensing light, ensuring reliable fingerprint detection without relying on uncontrollable ambient light.
2Measurement precision
If the photoelectric sensing device is placed closer to the substrate, then light loss is reduced and signal strength increases, but the structure becomes more compact and may interfere with other components
Solution Approach 1:
The patent resolves spatial constraints by transitioning to a stacked three-dimensional layer arrangement. Instead of lateral placement issues, the photoelectric sensing device is positioned in the vertical stacking sequence between the substrate and color filter substrate. This dimensional reorganization allows close proximity for high signal strength while maintaining clear separation from other components through vertical layering, avoiding interference while achieving detection sensitivity.
3Measurement precision
If multiple transistors and light shielding units are added to improve sensing control, then detection accuracy improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the array substrate into functionally independent units: multiple transistors (first and second transistors) are separately formed to control different aspects of the photoelectric sensing device, and light shielding units are segmented to correspond with each transistor. This modular segmentation allows precise control of fingerprint detection while enabling parallel fabrication processes, where each unit can be manufactured independently using standard thin-film transistor techniques, thus managing manufacturing complexity through systematic division.
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
Enhances fingerprint recognition accuracy by increasing the amount of light and signal received by the photoelectric sensing device, improving the detection of fingerprint ridge and valley positions.
Implementation Method 1
a photoelectric sensing device, wherein the substrate is provided with a fingerprint recognition region, and an orthographic projection of the photoelectric sensing device on the substrate is within the fingerprint recognition region
Implementation Method 2
a backlight module, disposed on a side, distal from the array substrate, of the color filter substrate, wherein light emitted from the backlight module is capable of passing through the fingerprint recognition region
Data Source
AI summary
Provided is a display panel. The display panel includes an array substrate, a color filter substrate, and a backlight module, wherein the array substrate includes a substrate and a photoelectric sensing device, the substrate is provided with a fingerprint recognition region, and an orthographic projection of the photoelectric sensing device on the substrate is within the fingerprint recognition region. The color filter substrate is disposed opposite to the array substrate, the backlight module is disposed on a side, distal from the array substrate, of the film substrate, and light emitted from the backlight module is capable of passing through the fingerprint recognition region.