Surface-Mounted Document Photosensor for Bill Validation
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Solution Overview
Problem
Existing document photosensors face challenges in accurately detecting optical features due to inaccuracies in mounting light emitting diodes, leading to deviations in light emission axes and increased size, which affects detection performance and validation accuracy.
Innovation Solution
A document photosensor design featuring surface-mounted light emitting and receiving elements on a substrate with a light diffusion chamber, allowing for precise alignment and reduced thickness, with light emitting diodes mounted at close intervals to improve detection accuracy and reduce the number of receiving elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light emitting diodes are mounted using conventional methods, then manufacturing is easier, but mounting precision deteriorates causing deviations in light emission axes
Solution Approach 1:
The patent replaces conventional mechanical mounting methods with surface-mount technology, where light emitting diodes are mounted on a substrate using soldering or reflow processes. This substitution enables precise positioning and alignment of the diodes, eliminating mounting precision issues while maintaining ease of manufacture through automated assembly processes.
2Measurement precision
If light emitting diodes are mounted at close intervals, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent combines multiple light emitting diodes and light receiving elements on a single substrate, integrating them into a compact sensor assembly. This merging approach enables close interval mounting for improved detection accuracy while reducing overall device complexity through unified structure and simplified interconnections.
Solution Approach 2:
The patent arranges light emitting diodes and light receiving elements in a two-dimensional array on the substrate surface, utilizing planar spacing rather than linear intervals. This dimensional approach allows multiple elements to be positioned at close intervals without significantly increasing device complexity, as the layout can be optimized in both horizontal and vertical directions.
3Quantity of substance
If the number of light receiving elements is reduced, then manufacturing costs decrease, but detection coverage area decreases
Solution Approach 1:
The patent employs lenses with curved surfaces to focus and redirect light from a wide area onto the light receiving elements. This optical curvature enables a reduced number of receiving elements to detect light across a larger coverage area, as the lenses concentrate light from peripheral regions onto the active sensing surfaces.
Solution Approach 2:
The patent introduces lenses as intermediary optical elements between the light emitting diodes and light receiving elements. These lenses mediate the light path, expanding the effective detection coverage area without requiring additional receiving elements, thereby maintaining cost-effectiveness while improving spatial coverage.
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
This design enhances detection performance by ensuring accurate alignment of light emitting diodes, reducing the size of the sensor assembly, and improving validation accuracy by effectively irradiating and receiving light across a wider area, while minimizing the number of light receiving elements to lower manufacturing costs.
Implementation Method 1
Each of light emitting diodes 114 and photo-transistors 115 has a plastic shell 114a, 115a
Implementation Method 2
optical sensor 111 for photo-electrically detecting optical features of bill 50 to produce detection signals
Data Source
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AI summary
A document photosensor is provided which comprises a substrate 11, 12, a bracket 41, 42 disposed on substrate 11, 12 for forming a light diffusion chamber 53 and a light receiving chamber 58 separated from each other, an LED chip 21, 31 surface-mounted on substrate 11, 12 in light diffusion chamber 53, and a PD chip 37, 38 surface-mounted on substrate 11, 12 in light receiving chamber 58. These chips 21, 37, 31 and 38 are secured at precise locations on a substrate 11 and 12 with accuracy on the order of a few micrometers or less to exactly detect by PD chip 37, 38 a light irradiated from LED chip 21 or 31 after reflection of the light on a bill 50 moved along a passageway 55 to improve validation performance of bill 50.