Display Assembly with Front-Surface Phototransistors for Fingerprint Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display assemblies face challenges in improving fingerprint recognition accuracy and simplifying the process complexity due to light loss and complex module structures for integrating touch control and fingerprint recognition functions.
Innovation Solution
A display assembly with a function module comprising phototransistors and switch transistors on the light-emitting surface of the display panel, integrating both fingerprint recognition and touch control functions, reducing module count and thickness by sharing manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical fingerprint recognition module is disposed on the back side of the substrate with light penetrating through the entire display panel, then the fingerprint recognition function can be implemented, but light loss is large which seriously affects accuracy of fingerprint recognition
Solution Approach 1:
The patent changes the spatial dimension by moving the fingerprint recognition function from the back side of the substrate to the front light-emitting surface of the display panel. This dimensional relocation allows the light path to be shortened significantly, as the light no longer needs to penetrate through the entire thickness of the display panel structure. The phototransistor array is positioned at the light-emitting surface where it can directly detect light variations caused by fingerprint patterns, thereby reducing light loss and improving recognition accuracy.
Solution Approach 2:
The patent introduces a light guide layer as an intermediary component between the light source and the phototransistor array. This light guide layer effectively directs and concentrates the light emitted by the display panel towards the phototransistor elements, minimizing light scattering and absorption by intermediate structural layers. The light guide layer acts as a mediator that optimizes the light transmission path, ensuring maximum light reaches the photosensitive elements for accurate fingerprint detection.
2Adaptability or versatility
If the touch control function and fingerprint recognition function are implemented through independent module structures, then both functions can be achieved, but the structure of the display assembly becomes complex and complexity of making process is increased
Solution Approach 1:
The patent merges the touch control function and fingerprint recognition function into a single integrated module structure. The phototransistor array serves dual purposes: it detects light variations for fingerprint recognition and simultaneously responds to touch pressure for touch control operations. By combining these functions at the light-emitting surface using shared components and structures, the patent eliminates the need for separate independent modules, thereby reducing structural complexity while maintaining both functional capabilities.
Solution Approach 2:
The patent implements multi-functionality by designing the phototransistor array to perform multiple functions. The same phototransistor elements that detect optical patterns for fingerprint authentication also detect mechanical pressure changes for touch control. This universal approach allows a single component structure to fulfill multiple functional requirements, eliminating redundancy and simplifying the overall display assembly architecture while maintaining adaptability for both fingerprint and touch operations.
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 shortening light transmission distance, reducing light loss, and simplifying the manufacturing process while maintaining display assembly integrity.
Implementation Method 1
light emitted by a fingerprint recognition light source irradiates to a finger. After being reflected by the finger, the light penetrates through the display panel, and then is received by a photosensitive element, to convert an optical signal into an electrical signal
Implementation Method 2
the first drain and the first gate partially overlap to form a first capacitor in a direction perpendicular to the display assembly
Data Source
AI summary
The present disclosure relates to display assemblies, display apparatus, and driving methods. One example display assembly includes a display panel and a function module located on a light-emitting surface of the display panel. A function unit in the function module includes at least one phototransistor and one switch transistor. The phototransistor includes a first active layer, a first gate, a first source, and a first drain. A material for making the first active layer includes an organic semiconductor material. The first active layer is located on a side of the first gate away from the display panel. The first drain and the first gate partially overlap to form a first capacitor. The switch transistor includes a second active layer, a second gate, a second source, and a second drain. The function unit includes a transparent electrode located on the first active layer and overlapping the first active layer.