Document Validator Light Pipe Core Illumination
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Solution Overview
Problem
Conventional bill validation systems using LED light sources face challenges in providing sufficient light signal intensity and accuracy due to varying bill positions within the passageway, leading to inconsistent signal measurements and increased fabrication costs.
Innovation Solution
A compact document validator subassembly featuring a light pipe core with a diffusing surface, a light control component with elongated apertures, and a prism structure layer, which ensures homogenous illumination across the document passageway, using multiple wavelengths of light and reflective shells to maintain constant irradiance levels regardless of document position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LED light sources and phototransistor receivers are positioned on opposite sides of a bill passageway to validate documents, then document validation capability is provided, but signal intensity levels are insufficient to accurately validate documents
Solution Approach 1:
A light pipe core is introduced as an intermediary component between the LED light sources and the documents. The light pipe core transports and distributes light uniformly across the document passageway, ensuring sufficient and consistent light intensity levels for accurate document validation without requiring complex high-power light source configurations
2Illumination intensity
If high power light sources and focusing elements are used to increase light signal intensity, then sufficient light intensity is achieved, but manufacturing cost increases
Solution Approach 1:
The light distribution system is segmented into multiple LED light sources positioned at different locations (including ends and sides of the light pipe core) rather than using a single high-power light source. This segmentation allows standard, cost-effective LED components to be used while achieving uniform illumination through the distributed light pipe core structure
3Reliability
If the bill passageway is designed to be large enough to avoid jams, then document handling reliability is improved, but sensor measurements are adversely affected because sensed signal varies depending upon document distance from light source
Solution Approach 1:
Multiple light sources are positioned at different locations around the light pipe core (ends and sides) to create locally optimized illumination zones. This ensures that regardless of where a document is positioned within the passageway, it receives adequate and consistent light intensity, maintaining measurement precision while allowing sufficient passageway dimensions for reliable document handling
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 provides accurate and consistent validation by ensuring homogenous illumination over the entire document passageway, improving recognition security and reducing signal variations, while maintaining a compact design suitable for limited physical spaces.
Implementation Method 1
a light pipe core having a top diffusing surface... which ensures homogenous illumination across the document passageway
Implementation Method 2
a light pipe core having a top diffusing surface... provides homogenous illumination over the entire width of the passageway
Implementation Method 3
a prism structure layer... between the top diffusing surface and the light control component
Implementation Method 4
using multiple wavelengths of light and reflective shells to maintain constant irradiance levels
Implementation Method 5
at least one light source coupled to the housing... one or more light emitting diodes (LEDs)... Additional light housings and LEDs of different wavelengths can be included
Data Source
Figure 1~2
Figure 3~5
Figure 4A
AI summary
A subassembly includes a housing, a light pipe core having a top diffusing surface, a light control component associated with the top diffusing surface, and at least one light source coupled to the housing. Preferably, the light control component includes at least one aperture or an array of apertures, and can be made, for example of a plastic or polymer material. The apertures can be in the shape of elongated slits, although other shapes are suitable for some applications. The subassembly can be used in various applications including as part of a document validator.