Multi-Layer Light-Shielding Image Module for Biometric Devices
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Solution Overview
Problem
Biometric devices require a large volume to accommodate image modules, making them unsuitable for miniaturized or portable electronic devices, and often suffer from reduced recognition success rates due to omitted components.
Innovation Solution
A thin image module with a light-screening structure comprising a photosensitive element, light-transmitting layer, and multiple light-shielding layers with adjustable light passage portions, along with a condensing structure to produce concentrated beams, which reduces device thickness and improves biometric recognition accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the components of an image module are omitted to achieve the purpose of thinning, then the thickness of the device is reduced, but the recognition success rate of the biometric device may be reduced
Solution Approach 1:
The light-shielding structure is divided into multiple layers (first light-shielding layer and second light-shielding layer) with different functions. The first layer blocks oblique light, while the second layer blocks scattered light, allowing each layer to be optimized independently for thinning while maintaining overall recognition accuracy
Solution Approach 2:
Different regions of the light-shielding layers are designed with different properties - the first light-shielding layer has light-shielding portions and light-transmitting portions with specific aperture ratios, while the second layer has corresponding structures optimized for their respective positions, allowing local optimization without compromising overall performance
2Volume of stationary object
If a large volume is used to accommodate an image module in the device, then the image module can be properly accommodated, but the device becomes unsuitable for use in miniaturized or portable electronic devices
Solution Approach 1:
The patent transitions from a single-layer light-shielding structure to a multi-layer vertical structure, utilizing the thickness dimension to achieve light shielding functionality that would otherwise require lateral expansion, thereby reducing the device's horizontal footprint while maintaining imaging quality
Solution Approach 2:
The second light-shielding layer is positioned within the structure defined by the first light-shielding layer, with the aperture of the second layer's light-transmitting portion smaller than that of the first layer, creating a nested configuration that maximizes space utilization and reduces overall device volume
3Use of energy by moving object
If the aperture of the light passage portion is increased to improve light transmission, then more light reaches the photosensitive element, but cross-talk between adjacent pixels increases reducing identification accuracy
Solution Approach 1:
The light-shielding portions are designed with asymmetric configurations relative to the light-transmitting portions, with specific aperture ratios that are not equal in all directions, allowing selective blocking of oblique light paths that cause cross-talk while preserving sufficient light transmission from vertical directions
Solution Approach 2:
The patent optimizes the aperture ratio parameter of the light-transmitting portions in both light-shielding layers, adjusting this critical parameter to achieve the optimal balance between light transmission efficiency and cross-talk suppression, with the first layer's aperture ratio specifically designed to block oblique light while maintaining adequate light throughput
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 enables the use of biometric devices in miniaturized electronic devices while enhancing the accuracy of identifying characteristic points by reducing cross-talk and improving image quality.
Implementation Method 1
Light passing through the condensing structure produces a concentrated beam
Implementation Method 2
The light-screening structure includes a first light-shielding layer disposed in the light-transmitting layer and having a first light passage portion
Data Source
AI summary
An image module includes a photosensitive element and a light-screening structure disposed on the photosensitive element. The light-screening structure includes a light-transmitting layer. The light-screening structure also includes a first light-shielding layer disposed in the light-transmitting layer and having a first light passage portion. The light-screening structure further includes a second light-shielding layer disposed between the first light-shielding layer and the photosensitive element and having a second light passage portion. The light-screening structure includes a condensing structure disposed on the light-transmitting layer. The first light passage portion and the second light passage portion correspond to the photosensitive element. Light passing through the condensing structure produces a concentrated beam, and the apertures of the first light passage portion and the second light passage portion are respectively adjusted according to the widths of the concentrated beam at the first light-shielding layer and at the second light-shielding layer.