Fingerprint Module on Array Substrate for LCD Sensitivity
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Solution Overview
Problem
Conventional liquid crystal display (LCD) products face poor sensitivity in fingerprint unlock systems due to weak light intensity detected by optical fingerprint identification modules, as light needs to penetrate through a color film substrate and is reflected back to the module, resulting in low sensitivity.
Innovation Solution
The LCD panel design positions the array substrate with the fingerprint identification module facing the user, incorporating thin film transistors and photodiodes with shading layers to block unnecessary light and enhance light path efficiency, using an intermediate layer made of perovskite between 250 nanometers and 3 microns thick, and including electron and hole transport materials to improve light conversion and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the fingerprint identification module is configured on the array substrate with light penetrating through the color film substrate, then the full screen display can be achieved, but the light intensity detected is very weak and sensitivity is very poor
Solution Approach 1:
The patent inverts the conventional light path configuration by positioning the fingerprint identification module on the array substrate side rather than the color film substrate side. This inversion shortens the light path and eliminates the need for light to penetrate through the color film substrate, thereby significantly improving detection sensitivity while maintaining full screen display capability
Solution Approach 2:
The patent introduces multiple shading layers (first shading layer, second shading layer, third shading layer) at different dimensional levels within the fingerprint identification module structure. These layers block light from unwanted directions (backlight, metal reflections) while allowing light from the finger to reach the photodiode, effectively solving the sensitivity problem through spatial dimensionality control
2Measurement precision
If light path is shortened by positioning the fingerprint identification module on the array substrate, then detection sensitivity improves, but the structure becomes more complex with multiple shading layers
Solution Approach 1:
The patent merges the fingerprint identification module with the array substrate structure, integrating the photodiode, thin film transistor, and multiple shading layers into a unified configuration. This merging approach shortens the light path and improves sensitivity while managing structural complexity through functional integration rather than separate components
Solution Approach 2:
The patent applies different shading layers with specific light-blocking properties at different locations within the fingerprint identification module. The first shading layer blocks light from the first passivation layer, the second shading layer blocks light from the second passivation layer, and the third shading layer blocks light from the gate electrode. This localized quality approach optimizes light blocking where needed while maintaining overall structural efficiency
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 significantly improves the sensitivity of the fingerprint identification module by shortening light paths and preventing misjudgments caused by backlight and metal reflections, addressing the issue of weak light intensity and low sensitivity in conventional systems.
Implementation Method 1
the photodiode configured for converting light energy into electrical energy
Data Source
AI summary
The present application provides a liquid crystal display panel and an liquid crystal display device, which includes an array substrate, a color film substrate, liquid crystals, and a fingerprint identification module, the array substrate is disposed on one side facing the user; the liquid crystal is positioned between the array substrate and the color film substrate; the fingerprint identification module is formed on one side of the array substrate facing the liquid crystal; the fingerprint identification module includes a thin film transistor and a photodiode for convert light energy into electrical energy, the thin film transistor is electrically connected to an output end of the photodiode.