Document Handler Sensor Shielding Against Liquid Ingress
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Solution Overview
Problem
Existing document handlers are vulnerable to damage from extraneous substances like dust and liquid, which can cause operational malfunctions and electrical damage to built-in sensors due to the inability to effectively prevent ingress of foreign matter.
Innovation Solution
A document handler design featuring a casement with a lower cover and tray forming a shield structure around the optical sensing element, made of light-permeable and water-shedding plastic, which hermetically seals the sensor and includes drainage openings to expel foreign substances, preventing damage and malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical sensor is attached in the vicinity or inside of the document inlet along the passageway, then the sensor can detect physical features of the document, but the sensor is exposed to extraneous objects intruding from outside which may cause operational malfunction or deterioration
Solution Approach 1:
The sensor assembly is segmented from the main passageway by creating a separate lower cavity (3d) enclosed by the lower cover (7) and lower tray (8). This segmentation allows the optical sensing element to be positioned for effective document detection while being isolated from extraneous substances that enter through the document inlet, thus resolving the contradiction between detection capability and sensor protection.
Solution Approach 2:
The lower cover (7) acts as an intermediary structure that allows light to pass through (enabling detection) while blocking liquid and extraneous substances (enabling protection). The cover's light-permeable and water-shedding properties make it an effective mediator that simultaneously supports both the detection function and the protection function.
2Measurement precision
If the lower cover is made of light-permeable plastic material, then light can pass through for document detection, but the cover may not provide sufficient protection against liquid and extraneous substance
Solution Approach 1:
The lower cover (7) is designed with specific material parameters that enable it to simultaneously achieve light permeability and liquid resistance. By selecting plastic material with appropriate optical and hydrophobic properties, the cover allows light transmission for document detection while repelling liquid and blocking extraneous substances, thus resolving the contradiction between light transmission and liquid protection.
3Reliability
If the sensor is sealed in a protected cavity, then the sensor is protected from extraneous substance, but the sensor cannot effectively detect document features
Solution Approach 1:
The lower cover (7) exhibits local quality variations where different regions have different properties: it is light-permeable in areas where light transmission is needed for detection, while being water-shedding and protective in areas exposed to liquid and extraneous substances. This local differentiation allows the single structure to simultaneously enable detection and provide protection, resolving the contradiction between sensor protection and detection accuracy.
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 effectively prevents damage to the optical sensing elements and electrical components by sealing them within a waterproof structure, ensuring continuous operation and preventing malfunctions due to extraneous substances, while allowing for accurate detection of document features through light transmission.
Implementation Method 1
lower cover (7) and lower tray (8) make up a shield structure for protecting lower optical sensing element (3a) from being damaged by penetrating extraneous substance or applied mechanical force. In addition thereto, lower optical sensing element (3a) can emit or receive a light through lower cover (7) to detect physical features of the document.
Implementation Method 2
lower cover (7) is formed of a light-permeable and water-shedding plastic material for providing a bottom surface of passageway (5)
Data Source
AI summary
A document handler is provided with a casement 1 which comprises a lower case 6 which has a lower cover 7 for providing a bottom surface of a passageway 5 and a lower tray 8 attached to a bottom of lower cover 7 to form therebetween a lower cavity 3d in which lower optical sensing element 3a of optical sensor 3 is disposed. Even if liquid spilled on a main surface of the table may often enter passageway 5 to the rear from the bill inlet, there is incurred no damage to electric instruments in lower cavity 3d by extraneous substance which is discharged through a drainage 15.