Indexed Optical Encoder Sub-Region Segmentation
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Solution Overview
Problem
Conventional optical encoders face challenges in achieving high accuracy, reliability, and ease of mass production, particularly in quickly registering the orientation of the encoder relative to a home or zero position, which limits their efficiency and precision.
Innovation Solution
The optical encoders incorporate an encoder disk with a patterned signal track and index track, featuring a plurality of optically detectable elements and sensors, along with a controller that determines the angular position using a detected binary sequence and look-up-table, allowing for efficient registration of the encoder's orientation with reduced rotational movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional optical encoders use a single index mark for orientation detection, then the device structure is simple, but the time required for orientation registration is excessive (requiring nearly one full rotation)
Solution Approach 1:
The encoder disk is segmented into multiple sub-regions (first sub-region, second sub-region, etc.) with distinct optical patterns. Each sub-region contains unique optically detectable elements that can be quickly identified by sensors, eliminating the need for slow sequential scanning and enabling rapid orientation determination without requiring nearly one full rotation
Solution Approach 2:
The encoder disk is pre-configured with multiple distinguishable sub-regions and their associated optically detectable elements before operation. This preliminary arrangement allows the sensor to immediately identify the current sub-region and determine orientation upon engagement, without requiring the encoder to rotate through most of its range to find a reference mark
2Measurement precision
If optical encoders require fine resolution for high accuracy, then measurement precision is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent transitions from relying solely on fine radial resolution to using angular dimensionality through multiple sub-regions arranged circumferentially. By distributing optically detectable elements across different angular positions in distinct sub-regions, the system achieves high measurement precision through spatial distribution rather than requiring extremely fine radial feature resolution, thereby reducing manufacturing complexity and cost
3Reliability
If conventional encoders rotate nearly one full rotation to register the index mark, then orientation can be determined, but productivity is reduced due to time loss
Solution Approach 1:
The encoder disk is divided into multiple sub-regions with distinct optical characteristics, allowing the sensor to quickly identify the current sub-region and determine orientation without completing a full rotation. This segmentation enables reliable orientation registration within a fraction of one rotation, significantly improving initialization speed and overall productivity
Solution Approach 2:
Different sub-regions utilize distinct optically detectable elements that create contrasting optical signals (analogous to color changes). These distinct optical signatures allow the sensor to rapidly identify which sub-region is currently positioned at the detection point, enabling quick and reliable orientation determination without time-consuming rotation
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 solution enhances the accuracy and reliability of optical encoders by reducing the time required for orientation registration, improving processing efficiency, and enabling larger bit depths without increasing computational resources, thus providing improved angular resolution and robustness.
Implementation Method 1
at least one sensor arranged to detect an optical signal associated with at least one optically detectable element
Implementation Method 2
detect movement in an illumination pattern that is imposed by an optical encoder disk by mechanisms such as diffraction
Data Source
AI summary
Optical encoders and methods of determining rotational movement are provided. The optical encoders include an encoder disk having a patterned signal track comprising a plurality of optically detectable elements disposed on a periphery of the encoder disk, wherein each optically detectable element is associated with a bit in a binary sequence, wherein each bit has a predefined bit depth, a boundary dividing the patterned signal track into at least two sub-regions, wherein each sub-region comprises a subset of the optically detectable elements, at least one sensor arranged to detect an optical signal associated with at least one optically detectable element, and a controller in communication with the at least one sensor, the controller configured to determine an angular position of the encoder disk, wherein the controller determines the angular position based on a detected binary sequence, a detected sub-region, and a look-up-table.