Banknote Sensing System with Oblique Light Incidence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional sensors in electronic transaction systems fail to accurately detect banknotes with transparent windows, leading to incorrect length calculation and potential double counting, as they mistake the transparent areas for the absence of a banknote due to high light transmission.
Innovation Solution
A sensing system that adjusts the angle of incidence of a light beam using light pipes with diverting surfaces and reflective surfaces to optimize the reflection coefficient, allowing for multiple passes through the banknote, thereby increasing the extinction ratio and enabling accurate detection of banknotes with transparent windows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensors with normal incidence light are used, then the system is simple and easy to operate, but banknotes with transparent windows cannot be accurately detected
Solution Approach 1:
The patent changes the angle of incidence parameter from normal (0 degrees) to oblique angles (e.g., 45 degrees) to improve detection accuracy. By adjusting this physical parameter, the system can distinguish transparent windows from absent banknotes while maintaining a relatively simple optical path configuration.
Solution Approach 2:
The patent introduces a reflective surface as an intermediary element to redirect transmitted light back through the banknote. This mediator enables the light to pass through the transparent window area multiple times, enhancing the detection signal without requiring complex multi-component sensor systems.
2Reliability
If light passes through transparent windows at normal incidence, then light transmission is high, but the system mistakes transparent areas for absence of banknote
Solution Approach 1:
The patent makes the light interact with the banknote continuously by reflecting transmitted light back through the same area. This continuous action ensures that the light repeatedly samples the transparent window region, accumulating sufficient signal information to reliably determine banknote presence and prevent misclassification.
Solution Approach 2:
The patent converts the harmful effect of high light transmission (which causes detection failure) into a beneficial effect. By using the highly transmissive property of transparent windows, the system guides light through the banknote and reflects it back, creating a detectable signal pattern that positively identifies the banknote's presence rather than indicating absence.
3Measurement precision
If traditional sensors are used, then the device complexity is low, but length calculation is inaccurate and double counting occurs
Solution Approach 1:
The patent changes the angle of incidence parameter to improve length measurement accuracy. By using oblique incidence, the light path length through the banknote increases, providing more accurate positional information for length calculation and preventing errors that lead to double counting.
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 system effectively differentiates between the presence and absence of banknotes with transparent windows, preventing miscounting and ensuring accurate validation by optimizing the reflected and transmitted light energy patterns.
Implementation Method 1
at least one light pipe having one or more diverting surfaces to direct the light beam at a predetermined angle of incidence onto the valuable document
Implementation Method 2
At least one reflective surface, to receive a first portion of the light beam transmitted through the valuable document and to reflect the first portion of the light beam towards the valuable document
Implementation Method 3
A light detector is configured to receive at least a second portion of the light beam transmitted through the valuable document. Intensity of the second portion of the light beam is based at least on the angle of incidence
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A sensing system to process at least one valuable document is described herein. The system includes a light source to generate a light beam. The system also includes at least one light pipe having one or more diverting surfaces to direct the light beam at a predetermined angle of incidence onto the valuable document. At least one reflective surface, to receive a first portion of the light beam transmitted through the valuable document and to reflect off the first portion of the light beam towards the valuable document, is included. A light detector is configured to receive at least a second portion of the light beam re-transmitted through the valuable document.