Under-Display Fingerprint Sensor With Liquid Crystal Light Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic devices with optical sensors for fingerprint recognition face challenges in improving sensing sensitivity due to noise interference from external light, which affects the accuracy and reliability of fingerprint detection.
Innovation Solution
The electronic device incorporates a liquid crystal member with a first and second liquid crystal electrode and a liquid crystal layer, where the liquid crystal molecules can align irregularly or regularly depending on the voltage difference, enhancing light transmittance and sensitivity by adjusting the alignment of liquid crystal molecules to specific wavelengths, and includes a color filter layer to selectively transmit light, thereby improving the sensing capability of the light receiving element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a liquid crystal member is added to improve light transmittance and sensing sensitivity, then the sensing sensitivity is improved, but the device complexity increases
Solution Approach 1:
The liquid crystal member is integrated into the display element layer structure, allowing it to serve dual purposes: maintaining display functionality and enhancing light transmittance to the light receiving element. This multi-functionality approach improves sensing sensitivity without requiring a completely separate system, thereby limiting the increase in device complexity.
Solution Approach 2:
The liquid crystal member is nested within the existing display element layer structure, positioned between the pixel defining film and the input detection layer. This nesting approach allows the liquid crystal member to be incorporated into the existing device architecture without requiring a completely new structure, thus improving sensing sensitivity while minimizing the increase in device complexity.
2Measurement precision
If liquid crystal molecules are aligned regularly by applying voltage to improve light transmittance, then sensing sensitivity improves, but energy consumption increases
Solution Approach 1:
The liquid crystal molecules are pre-aligned in a regular configuration during the manufacturing process, eliminating the need for continuous voltage application to maintain the aligned state. This preliminary action approach allows the light receiving element to benefit from optimized light transmittance without the ongoing energy consumption that would be required to maintain the alignment through active voltage control.
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 the sensitivity of the light receiving element by optimizing light transmittance and selectively allowing specific wavelengths to reach the sensor, thereby improving the accuracy and reliability of fingerprint recognition despite external light interference.
Implementation Method 1
the liquid crystal member includes: a first liquid crystal electrode; second liquid crystal electrode disposed on the first liquid crystal electrode; and liquid crystal layer disposed between the first liquid crystal electrode and the second liquid crystal electrode, and including a plurality of liquid crystal molecules
Implementation Method 2
when there is no voltage difference between the first liquid crystal electrode and the second liquid crystal electrode, the liquid crystal member may operate in a first mode in which the liquid crystal molecules are irregularly arranged; and when there is a voltage difference between the first liquid crystal electrode and the second liquid crystal electrode, the liquid crystal member may operate in a second mode in which the liquid crystal molecules are regularly arranged
Implementation Method 3
a color filter layer to selectively transmit light, improving the detection capabilities of the light receiving element
Implementation Method 4
an optical method for detecting incident light using an optical sensor
Data Source
AI summary
An electronic device includes a base layer, a circuit layer on the base layer, a display element layer on the circuit layer, the display element layer including a pixel defining film having an opening part, and a light emitting element and a light receiving element divided by the pixel defining film, an input detection layer on the display element layer and overlapping the light emitting element, and a liquid crystal member on the display element layer and overlapping the light receiving element.