Dome-Shaped Guide Deflects Reflections in Palm Vein Sensors
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Solution Overview
Problem
Existing palm vein authentication systems face difficulties in correct hand positioning and sensor device protection, with flat glass covers causing unwanted reflections and potential damage.
Innovation Solution
A dome-shaped guide device for hand positioning, transparent to emitted radiation, deflects reflected radiation laterally, allowing increased distance between the guide and sensor, and incorporating miniature radiation sources and a camera for image acquisition, with a status display using concentrically arranged LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat glass plate is used to cover the sensor device, then the sensor device is protected from soiling and damage, but unwanted reflections occur on the glass surface that negatively affect the measurement result
Solution Approach 1:
The patent applies a dome-shaped cover instead of a flat glass plate. The curved surface of the dome deflects reflected radiation laterally away from the sensor device, eliminating unwanted reflections that would occur on a flat surface while still providing protection from soiling and damage.
2Reliability
If the sensor device is covered with a flat glass plate, then the sensor device is protected, but the distance between the glass plate and sensor device must be kept minimal to avoid reflections, limiting the protective function
Solution Approach 1:
The dome-shaped cover allows for a larger distance between the cover and sensor device compared to a flat plate. The curved geometry naturally deflects reflections laterally, so the protective cover can be positioned farther from the sensor without causing unwanted reflections, thus improving both protection and measurement quality.
3Ease of operation
If a guide device with specific surfaces is used for hand positioning, then the hand can be supported in the required manner, but correct positioning is only possible with difficulty
Solution Approach 1:
The dome-shaped guide device provides a curved surface that naturally guides the hand into the correct position. The spherical geometry offers intuitive tactile feedback and broader acceptable positioning areas compared to flat surfaces, making correct hand positioning easier and more intuitive for users.
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 hand positioning ease, protects the sensor device from contamination and misalignment, reduces unwanted reflections, and allows for a safer, more reliable palm vein authentication process.
Implementation Method 1
a sensor device (21) means for emitting radiation in the form of infrared light towards the palm of the hand (12) and means for detecting radiation reflected from a palm of the hand
Implementation Method 2
detecting radiation reflected from a palm of the hand
Implementation Method 3
the guide device (26) is designed in the shape of a dome... so that radiation from the device for emitting radiation in the form of infrared light, which is reflected back directly on the guide device, is deflected laterally
Data Source
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AI summary
The present invention relates to an image acquisition device (20) for acquiring a pattern of a palm (12) for the purpose of palm authentication, having a sensor unit (21), comprising a unit (22) for emitting radiation in the direction of the palm (12) and a unit (25) for acquiring reflected radiation from a palm (12), and having a guide unit (26) for positioning the palm (12) in relation to the sensor unit (21). In order to avoid undesired reflections, it is provided according to the invention that the guide unit (26) is implemented in a dome shape and spans the sensor unit (21). The image acquisition device (20) may advantageously be a component of a system (10) for entry and/or access control.