Under-screen Fingerprint Sensor via Light Path Shortening
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Solution Overview
Problem
In liquid crystal display panels, the multilayer structures weaken the light reflected by fingerprints, leading to incomplete or useless fingerprint information, affecting the fingerprint identification function and user experience.
Innovation Solution
The display panel design includes a fingerprint identification layer with sensors on a second substrate close to the glass cover, reducing the light path and using an upper polarizer with light transmitting units to minimize light weakening, thereby improving fingerprint identification effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fingerprint identification sensor is placed on the thin film transistor array substrate in a liquid crystal display panel, then the fingerprint identification function can be integrated into the display panel, but the multilayer panel structures (color filter substrate layer and liquid crystal layer) weaken the light reflected by the fingerprint, resulting in incomplete or useless fingerprint information
Solution Approach 1:
The patent extracts the fingerprint identification sensor from the traditional position on the thin film transistor array substrate and relocates it to the color filter substrate. This extraction allows the sensor to be positioned where it can directly receive reflected light without passing through the liquid crystal layer, thereby solving the problem of light weakening while maintaining integration with the display panel structure
Solution Approach 2:
The patent introduces a light guide layer as an intermediary component between the fingerprint identification sensor and the liquid crystal layer. This light guide layer directs the reflected light from the fingerprint directly to the sensor, preventing the light from being weakened by the liquid crystal layer while maintaining the overall display panel structure
2Measurement precision
If the fingerprint identification sensor is placed on the side or backside of the phone, then the multilayer panel structures do not weaken the reflected light, but this solution does not achieve true under-screen fingerprint identification and affects the full-body screen display
Solution Approach 1:
The patent merges the fingerprint identification sensor with the color filter substrate layer of the display panel, creating an integrated structure where the sensor becomes an inherent part of the display assembly. This merging allows the fingerprint identification function to be truly integrated under the screen while maintaining the full-body screen display without borders or interruptions
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 enhances fingerprint identification by shortening the light path to the sensors and reducing the impact of the liquid crystal layer, resulting in improved fingerprint detection accuracy and user experience.
Implementation Method 1
an upper polarizer is disposed between the second substrate and the glass cover and comprises light transmitting units vertically corresponding to the fingerprint identification sensors
Implementation Method 2
a liquid crystal layer comprising liquid crystals and disposed between the first substrate and the second substrate
Implementation Method 3
a backlight module configured as a light emitting unit of the display panel
Data Source
AI summary
A display panel is provided, comprising a backlight module, a first substrate, a liquid crystal layer, a second substrate, and a glass cover, wherein the second substrate comprises a fingerprint identification layer configured for identifying information from a fingerprint of a user. The second substrate provided with the fingerprint identification layer is disposed close to the glass cover, making the fingerprint identification layer closer to the fingerprint of the user, shortening a path of the light reflected by the fingerprint to the fingerprint identification sensors, and improving fingerprint identification effectiveness.