Optical Fingerprint Detection in Thin Display Panels
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Solution Overview
Problem
Capacitive fingerprint recognition in display panels often suffers from parasitic capacitance interference with other components, reducing accuracy due to signal interference between fingerprint detection and display signals.
Innovation Solution
A fingerprint identification display device incorporating a light guide plate, photosensitive induction units, and a light emitting component that emits modulated light in a total reflection mode, allowing for accurate fingerprint detection without interfering with display signals, using a photosensitive diode and control switching transistor to convert modulated light into electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a capacitive fingerprint identification component is embedded in the display panel, then the display panel achieves a light thinning design, but parasitic capacitance is generated with other components causing signal interference and reduced fingerprint recognition accuracy
Solution Approach 1:
The patent replaces the capacitive sensing mechanism with an optical sensing mechanism. A light guide plate, light emitting component, and photosensitive induction units are used to detect fingerprint ridges and valleys through light reflection and absorption differences, eliminating the parasitic capacitance issue inherent in capacitive structures while maintaining thin panel design.
Solution Approach 2:
The patent introduces a light guide plate as an intermediary component between the light emitting component and the photosensitive induction units. This light guide plate transmits modulated light through total internal reflection and enables optical signal transmission without direct electrical contact, thereby avoiding parasitic capacitance interference while achieving accurate fingerprint detection.
2Length of moving object
If a capacitive fingerprint identification component is embedded in the display panel, then the display panel achieves a light thinning design, but signal interference occurs between fingerprint detection and display signals
Solution Approach 1:
The patent replaces the capacitive sensing mechanism with an optical sensing mechanism. A light guide plate, light emitting component, and photosensitive induction units are used to detect fingerprint ridges and valleys through light reflection and absorption differences, eliminating the parasitic capacitance issue inherent in capacitive structures while maintaining thin panel design.
Solution Approach 2:
The patent introduces a light guide plate as an intermediary component between the light emitting component and the photosensitive induction units. This light guide plate transmits modulated light through total internal reflection and enables optical signal transmission without direct electrical contact, thereby avoiding parasitic capacitance interference while achieving accurate fingerprint detection.
3Measurement precision
If photosensitive induction units are arranged below the light guide plate, then accurate fingerprint detection is achieved without interfering with display signals, but the device structure becomes more complex
Solution Approach 1:
The patent merges the fingerprint sensing function with the display panel structure by integrating the light guide plate, light emitting component, and photosensitive induction units into the existing display layers. This integration approach allows accurate optical fingerprint detection while utilizing the display panel's existing structural framework, thereby reducing overall device complexity despite adding functional components.
Solution Approach 2:
The light guide plate serves multiple functions: it guides light from the light emitting component, transmits modulated light through total internal reflection to the photosensitive induction units for fingerprint detection, and maintains the thin profile of the display panel. This multi-functionality reduces the need for separate dedicated components, simplifying the overall device structure.
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 solution enables efficient and accurate fingerprint detection with minimal interference from other display components, maintaining high-quality fingerprint recognition and display performance.
Implementation Method 1
the modulated light is transmitted between the light guide plate and the display panel in a total reflection mode
Implementation Method 2
the photosensitive diode is configured to sense the modulated light reflected by a ridge of a fingerprint, and the control switching transistor is configured to control the photosensitive diode to convert the modulated light into a potential
Data Source
AI summary
A fingerprint identification display device includes: a display panel; a light guide plate arranged on a light emitting surface of the display panel; a light emitting component configured to emit modulated light; and a plurality of photosensitive induction units arranged in an array and arranged below the light guide plate, in which the modulated light is transmitted between the light guide plate and the display panel in a total reflection mode.