Liquid Crystal Display Module Fingerprint Crosstalk Reduction
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Solution Overview
Problem
Liquid crystal display modules face significant crosstalk issues when attempting to implement fingerprint recognition due to interference light received by the fingerprint recognition unit.
Innovation Solution
A liquid crystal display module design featuring a display panel with a first substrate, a second substrate, a liquid crystal layer, a patterned polarizer, and fingerprint identification units, where light from the backlight module passes through filter parts to diffuse on a touched body and is filtered by a second area of the polarizer to reach the fingerprint identification units, while analyzer units ensure only relevant light reaches the recognition units, minimizing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal display panel uses a conventional structure without specialized polarizer patterns, then the display function is simple, but fingerprint recognition suffers from serious crosstalk due to interference light
Solution Approach 1:
The first polarizer is divided into a first area corresponding to filter parts and a second area corresponding to light shielding parts, with different polarization directions. This segmentation allows the polarizer to differentially transmit light based on spatial position, enabling fingerprint recognition while maintaining display functionality and reducing crosstalk.
Solution Approach 2:
Different regions of the first polarizer are assigned different polarization directions tailored to their specific functions. The first area has a polarization direction optimized for display, while the second area has a polarization direction optimized for fingerprint recognition, allowing each region to perform its specific function effectively.
2Measurement precision
If light from the backlight module passes through filter parts to diffusely reflect on the touched body, then fingerprint imaging is enabled, but interference light reaches the fingerprint identification units causing crosstalk
Solution Approach 1:
The second area of the first polarizer acts as an intermediary element between the light shielding parts and the fingerprint identification units. It selectively transmits light based on polarization direction, allowing useful fingerprint light to pass while blocking harmful interference light, thus reducing crosstalk.
Solution Approach 2:
The harmful interference light is extracted and blocked by the second area of the first polarizer, which is specifically designed to prevent such light from reaching the fingerprint identification units. This separation ensures that only relevant light reaches the recognition units.
3Object-affected harmful factors
If analyzer units are added between the second area and fingerprint recognition units, then crosstalk is minimized, but device structure becomes more complex
Solution Approach 1:
The analyzer units are integrated into the existing display panel structure, combining the functions of light analysis and fingerprint recognition in a unified system. This merging approach minimizes additional complexity while achieving effective crosstalk reduction.
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 separates fingerprint identification light from interference light, allowing for accurate fingerprint recognition without crosstalk, enabling reliable fingerprint imaging while maintaining display functionality.
Implementation Method 1
a first polarizer comprising a first area and a second area, wherein the first area corresponds to the filter parts, the second area corresponds to the light shielding parts, a polarization direction of the first area is perpendicular to a polarization direction of the second area
Implementation Method 2
a liquid crystal layer disposed between the first substrate and the second substrate
Implementation Method 3
Light emitted by the backlight module passes through the filter parts to diffusely reflect on a surface of a touched body
Data Source
AI summary
A liquid crystal display module includes a display panel and a backlight module. The display panel includes a first substrate and a second substrate disposed opposite to each other, a liquid crystal layer, a first polarizer, and a plurality of fingerprint recognition units. The first substrate includes filter parts and light shielding parts. The first polarizer uses a patterned polarizer. The display panel can realize fingerprint identification while displaying. The fingerprint recognition unit is provided with an analyzer unit to avoid crosstalk.