Optical Position Encoder LED Window Coating for Sharper Signal Resolution
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Solution Overview
Problem
Optical position encoders face limitations in resolution due to imperfections in light emission properties caused by glass plates and manufacturing tolerances, leading to refractions, shadows, and reduced signal quality.
Innovation Solution
The method involves coating and de-coating the light exit surface of the LED light source to create a precise light exit window, which is independent of the LED light source's dimensions, allowing for improved emission properties and higher resolutions by avoiding undesired refractions and reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass plate is arranged above the LED light source to enable defined emission and prevent damage, then the LED light source is protected and emission is controlled, but refractions and reflections occur that impair light emission and reduce signal quality
Solution Approach 1:
The harmful glass plate is completely removed from the optical path. The LED light source is mounted directly on the circuit board with its light exit surface exposed, eliminating the source of refractions and reflections that degraded measurement precision.
Solution Approach 2:
The circuit board is selectively structured: it remains intact in most areas for mechanical support and electrical connections, but is locally removed (cut away) in the region directly above the LED light source to create an unobstructed light exit path, combining structural integrity with optical clarity.
2Ease of operation
If a glass plate is arranged above the LED light source, then emission direction is controlled, but undesired refractions occur at transitions that reduce resolution
Solution Approach 1:
The glass plate causing refractions is removed entirely. Instead, the circuit board itself is used as the mounting structure, with a localized removal creating a clean aperture that eliminates intermediate optical interfaces and their associated refractions.
Solution Approach 2:
The circuit board serves as both the electrical connection medium and the mechanical support structure, while also forming the optical aperture. This eliminates the need for a separate glass plate intermediary, reducing the number of optical interfaces from two (air-glass and glass-air) to one (air-to-open space).
3Reliability
If the LED light source is enclosed on all sides by the molded housing, then component protection is achieved, but light emission is impaired and structure is complex
Solution Approach 1:
The housing structure is merged with the circuit board mounting structure. The housing contains an integrated opening that serves both as the light exit aperture and as part of the structural enclosure, eliminating the need for separate glass plates or complex multi-component assemblies.
Solution Approach 2:
The housing opening serves multiple functions: it provides the light exit path, maintains structural enclosure for component protection, and defines the optical geometry. This multi-functionality reduces overall device complexity while achieving both protection and emission requirements.
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 approach enhances signal quality and resolution by reducing the impact of manufacturing tolerances and production method variations, enabling uniform emission properties across different LED light sources and batches, and allowing for sharper light exit windows.
Implementation Method 1
an LED light source is embedded into a molded housing in such a way that a light exit surface of the LED light source is exposed to the outside
Implementation Method 2
undesired refractions of the light beams can occur at the transitions between LED light source and glass plate
Implementation Method 3
reflections can occur, so that, for example, external light is also deflected in the direction of the measuring scale
Data Source
AI summary
A method for producing an optical position encoder including an optoelectronic component and a measuring scale which is illuminated by an LED light source of the optoelectronic component. The LED light source is molded not a mold housing such that a light outlet surface of the LED light source is outwardly exposed, and the light outlet surface has a coating and is uncoated in some regions in order to provide a light outlet window. The disclosure additionally relates to an optical position encoder including an optoelectronic component with a mold housing in which an LED light source is arranged such that a light outlet surface of the LED light source is outwardly exposed, the light outlet surface being coated and having an uncoated light outlet window, and including a measuring scale which is illuminated by the LED light source of the optoelectronic component.