Detector Array Housing Alignment Pins for LED and Photodiode Positioning
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Solution Overview
Problem
Existing drop detectors face challenges in accurately aligning multiple light sources and photo detectors due to poor manufacturing tolerances and high costs, which complicates the detection of nozzle health in print elements like inkjet printheads, leading to inefficiencies in diagnosing faulty nozzles.
Innovation Solution
The use of a detector array with a housing system featuring alignment elements, such as pins and control pads, to precisely align light sources and photo detectors within compartments, ensuring each LED is opposite a photodiode, thereby maintaining alignment and reducing misalignment issues caused by manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple light sources and photo detectors are used in a drop detector, then the detection speed and productivity are improved, but the alignment precision deteriorates due to poor manufacturing tolerances
Solution Approach 1:
The patent introduces alignment pins as intermediary elements that mediate between the housing structure and the light sources/photo detectors. These pins provide physical reference points that guide the positioning of optical components, ensuring accurate alignment without requiring high-precision manufacturing of the housing itself. The pins act as a buffer that compensates for manufacturing tolerances in the surrounding structure.
Solution Approach 2:
The alignment pins are pre-positioned in the housing at specific locations before the light sources and photo detectors are installed. This preliminary action establishes a fixed reference framework that guides subsequent component placement, ensuring that multiple optical elements can be accurately aligned relative to each other without requiring the housing itself to be manufactured with tight tolerances.
2Manufacturing precision
If alignment elements are added to improve alignment precision, then the manufacturing complexity and device complexity increase
Solution Approach 1:
The alignment system is segmented into discrete, modular components: alignment pins positioned at specific locations in the housing, and corresponding alignment features on the light source and photo detector assemblies. This segmentation allows each component to be manufactured independently with standard tolerances, then assembled together to achieve the required overall alignment precision, reducing the complexity of manufacturing the entire system as a single high-precision unit.
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 alignment system enables efficient detection of nozzle health across a print element, reducing the time required to diagnose nozzle issues and improving the accuracy of drop detection, allowing for quicker identification of faulty nozzles and enhanced print element performance.
Implementation Method 1
The first housing is for a plurality of light sources and the second housing is for a plurality of photo detectors
Implementation Method 2
The drop detector detects a droplet because the droplet intersects the path of light emitted from a light source
Data Source
AI summary
There is disclosed a housing including a plurality of compartments for housing a plurality of LEDs or photo detectors. Each compartment has a number of control pads projecting inwardly and a number of protrusions. The control pads are configured to provide a contact surface for the LEDs or photo detectors to control the alignment and position of each of the plurality of LEDs or photodiodes within each of the plurality of compartments. Each of the protrusions urges each of the plurality of LEDs or photodiodes against the respective control pads to control the alignment of the LEDs or photodiodes in the housing. A detector array including a casing, an LED housing and a photodiode housing is also disclosed.