Vibrating Photosensitive Substrate for Non-Contact Fingerprint Detection
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Solution Overview
Problem
Conventional infrared detection devices, such as fingerprint recognizing chips, are limited to contact detection due to their fixed microlens curvature, which prevents non-contact fingerprint recognition and lacks the ability to detect objects at varying distances.
Innovation Solution
A photosensitive assembly comprising a light-transmissive substrate with a light sensor and a vibration member that drives the substrate to vibrate, creating an undulated photosensitive area for light convergence, allowing for adjustable focus and detection of objects at different ranges without a microlens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed microlens is used to converge infrared light, then detection efficiency is improved, but the device is limited to contact detection only and cannot detect objects at varying distances
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed microlens with a flexible light-transmissive substrate that can dynamically change its surface shape. The substrate transitions from a flat state to an undulated state with microlens-like curvature through external actuation, enabling the system to adapt its optical properties in real-time. This dynamic shape change allows the device to switch between contact detection mode and non-contact detection mode at varying distances, resolving the contradiction between detection efficiency and detection distance range.
Solution Approach 2:
The patent employs parameter changes by modifying the physical state and geometric parameters of the light-transmissive substrate. By changing the substrate's surface curvature from flat to undulated, and by adjusting the degree of undulation, the system can optimize light convergence for different detection scenarios. This parameter adjustment enables the device to maintain high detection efficiency across various detection distances, addressing the limitation of fixed microlens curvature.
2Measurement precision
If a microlens is used for light convergence, then detection efficiency is improved, but device thickness and volume increase
Solution Approach 1:
The patent applies the extraction principle by removing the separate microlens component from the detection device. Instead of using a discrete microlens element that adds to device thickness, the invention integrates the light-converging function directly into the light-transmissive substrate itself. The substrate's surface is actuated to form microlens-like structures temporarily during operation, eliminating the need for a permanent microlens component and thereby reducing overall device thickness and volume.
Solution Approach 2:
The patent implements multi-functionality by making the light-transmissive substrate serve dual purposes: it acts as both the structural support element and the optical focusing element. The substrate can switch between a flat configuration (reducing thickness) and an undulated configuration with microlens curvature (providing light convergence). This multi-functional design eliminates the need for separate microlens components, achieving both thin form factor and effective light convergence.
3Measurement precision
If contact detection is used, then detection efficiency is improved, but the device lacks versatility for non-contact detection applications
Solution Approach 1:
The patent applies dynamics by enabling the light-transmissive substrate to dynamically change its surface morphology between flat and undulated states. This dynamic transformation allows the device to switch between different detection modes: when undulated, it provides contact detection with high efficiency similar to traditional microlens systems; when flat, it enables non-contact detection at varying distances. This dynamic adaptability resolves the contradiction between detection efficiency and detection mode flexibility.
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
Enables both contact and non-contact detection capabilities while reducing device thickness and volume, facilitating a slim and versatile electronic device design.
Implementation Method 1
a vibration member, configured to drive the light-transmissive substrate to vibrate, such that a photosensitive area of the light-transmissive substrate is in an undulated shape
Data Source
AI summary
Disclosed are a photosensitive assembly, a method for manufacturing the same, and an electronic device. The photosensitive assembly includes a light-transmissive substrate, a light sensor, and a vibration member. The light sensor is disposed on a side of the light-transmissive substrate, and the vibration member is configured to drive the light-transmissive substrate to vibrate, such that a photosensitive area of the light-transmissive substrate is in an undulated shape.