Photoelectric Encoder Multiple Light-Receiving Segmentation
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Solution Overview
Problem
Conventional photoelectric encoders face challenges in achieving a wide detection range without increasing the size of the optical system, and maintaining sensitivity and reliability, especially when dealing with stains and air gap fluctuations.
Innovation Solution
The solution involves dividing the detection range into smaller areas with multiple light-receiving systems, using telecentric optical systems, and averaging outputs to detect movement and posture, while ignoring low-correlation patterns to enhance reliability and reduce sensitivity to stains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detection range is widened, then the sensitivity to stains on the scale is decreased, but the optical system becomes large in size
Solution Approach 1:
The patent divides the detection range into multiple smaller detection areas, with each area having its own light-receiving element. This segmentation allows the optical system to maintain a compact size while achieving a wide overall detection range by combining multiple small detection areas. Each light-receiving element processes a limited area, avoiding the need for a single large optical system.
2Measurement precision
If the detection range is widened, then the measurement capability is improved, but the optical system size increases
Solution Approach 1:
The detector is divided into multiple light-receiving elements, each responsible for a specific detection area. This segmentation enables the system to achieve a wide measurement range by combining the outputs of multiple small detection areas, without requiring a single large optical system.
Solution Approach 2:
The patent extends the detection capability from a single linear dimension to a two-dimensional detection area by arranging multiple light-receiving elements in both the detection direction and the width direction, achieving wide-range measurement without proportionally increasing optical system size in all dimensions.
3Measurement precision
If multiple light-receiving elements are used to divide the detection range, then the detection range is widened, but the device complexity increases
Solution Approach 1:
The patent combines multiple light-receiving elements into a single integrated detector structure, where the individual elements work together as a unified system. This merging approach maintains the benefits of divided detection areas while reducing overall device complexity through integration.
Solution Approach 2:
Each light-receiving element is designed with universal functionality to detect patterns in its specific area, allowing the same structural design to be replicated across multiple elements. This multi-functionality reduces design complexity and facilitates standardized manufacturing.
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 allows for a wide detection range with a compact optical system, reducing sensitivity to stains and air gap fluctuations, and improving the reliability of position detection in both incremental and absolute encoders.
Implementation Method 1
a photoelectric encoder having a detector that is relatively displaceable to a scale having a predetermined pattern formed thereon
Data Source
AI summary
In a photoelectric encoder (incremental encoder and absolute encoder) having a detector that is displaceable relative to a scale having a predetermined pattern (incremental pattern and pseudorandom pattern) formed thereon, the detection range, to be simultaneously detected, of the pattern is divided in at least the detection direction, and a plurality of light-receiving systems are provided to detect each of the respective detection areas, whereby measurement of a wide detection range is enabled by using a small-sized and simple optical system and light-receiving system.