Row-Activatable Encoder Sensor Layout for Faster Position Readout
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Solution Overview
Problem
Existing position measurement encoders face challenges in efficiently reading scale features due to limitations in sensor design, particularly in terms of flexibility and speed of readout, which can affect accuracy and ease of installation.
Innovation Solution
A position measurement encoder with a sensor comprising a one-dimensional array of columnar pixels divided into rows, where each row is individually activatable, allowing selective choice of contributing sensing sections for improved flexibility and faster readout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a reflective scale is used in the position encoder, then the encoder can be constructed with simple structures and at low costs, but the encoder cannot be applied to environments requiring contactless operation and high hygiene standards
Solution Approach 1:
The patent replaces the mechanical contact-based reflective scale system with a contactless optical measurement system. The measuring device uses a light source and detector to measure the position of the scale without physical contact, enabling application in hygienic environments while maintaining the simplicity of the scale construction.
2Volume of moving object
If the detector is positioned close to the light source, then the device can be made compact, but the detector is exposed to strong direct light from the light source
Solution Approach 1:
The patent positions the detector at an angle to the optical axis, creating a spatial separation that allows the detector to be close to the light source while avoiding direct light exposure. The detector receives reflected light from the scale at an angled position, effectively using spatial dimensionality to resolve the conflict between compactness and light exposure protection.
Solution Approach 2:
The reflective scale acts as an intermediary element between the light source and detector. The light source illuminates the scale, and the scale reflects the light to the detector, preventing direct light exposure while enabling close positioning of the detector to the light source for compact device design.
3Measurement precision
If the detector receives reflected light from the scale, then the position can be measured, but the detector also receives stray light from the light source causing measurement errors
Solution Approach 1:
The patent uses angular separation in the optical path to distinguish reflected light from stray light. The detector is positioned to receive light only from a specific angular direction (from the scale reflection), while blocking light from other directions (direct stray light from the source), thereby improving measurement accuracy.
Solution Approach 2:
The patent applies directional selectivity to the detector, making it sensitive only to light coming from a specific direction (the reflected light path from the scale). This local quality control in light reception allows the detector to distinguish between useful reflected light and harmful stray light, maintaining measurement precision.
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 configuration enhances encoder performance by reducing position errors and simplifying installation, while enabling faster and more accurate measurement of position and its derivatives.
Implementation Method 1
a reflective scale which is reflected light from a light source to a detector
Data Source
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AI summary
A position measurement encoder comprising a scale and a readhead, the readhead comprising a sensor for sensing the scale, the sensor comprising a one- dimensional array of columnar pixels, configured such that the one-dimensional array of columnar pixels is divided into a plurality of rows wherein each columnar pixel has at least one individual sensing section in each row arranged to contribute to the columnar pixel's output. Each row is individually activatable so that which one or more of the individual sensing sections in the columnar pixels contribute to each columnar pixel's output can be selectively chosen and changed on a row-by-row basis.