Encoder Rotary Disc Pattern Arrangement
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Solution Overview
Problem
Existing encoder configurations, such as those described in JP-UM-A-58-101173, require sensors with different resolutions for each slit, leading to a complex configuration and increased manufacturing costs due to the need for distinguishing rotational positions using slits with varying transmittance, width, and pitch.
Innovation Solution
An encoder design featuring a rotary disc with first and second patterns arranged at specific intervals on concentric circles, where the number of cycles of detection signals from each pattern are relatively prime, allowing for the use of sensors with the same resolution to detect rotational positions, thereby simplifying the configuration and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors with different resolutions are used for each slit to distinguish rotational positions, then measurement precision is improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent applies homogeneity by using sensors with the same resolution for all slits instead of requiring different resolutions. The rotary disc is designed with multiple slits that can be detected by identical sensors, eliminating the need for complex sensor selection and configuration while maintaining accurate rotational position detection through the mathematical relationship between slit positions and sensor outputs
2Measurement precision
If sensors with different resolutions are used for each slit to distinguish rotational positions, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
By designing the encoder to use identical sensors for all slits, the patent reduces manufacturing costs. The standardized sensor configuration allows for bulk procurement, simplified assembly procedures, and reduced inventory complexity, while the precise rotational position detection is achieved through the geometric arrangement of slits and signal processing algorithms
3Measurement precision
If slits with varying transmittance, width, and pitch are used to distinguish rotational positions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the rotational position detection function into multiple identical slits arranged in specific patterns on the rotary disc. Instead of using complex slits with varying properties, the detection is achieved by combining outputs from multiple simple, identical slits processed through mathematical algorithms, thereby reducing manufacturing complexity while maintaining 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
The proposed encoder design enables efficient detection of rotational positions with a simple configuration, reducing manufacturing costs by utilizing sensors with the same resolution for both patterns, while maintaining accurate position specification.
Implementation Method 1
an optical rotary encoder is disclosed which performs detection by distinguishing rotational positions (angles) using different slits
Data Source
AI summary
An encoder including a rotary disc that rotates around a rotating shaft, and a sensor that detects a rotational position of the rotary disc, in which the rotary disc is provided with first patterns and second patterns, the first patterns are arranged at positions obtained by equally dividing a first circumference which is a circumference of a first circle into M (M is natural number of 2 or more) at intervals, the second patterns are arranged at positions obtained by equally dividing a second circumference which is a circumference of a second circle which is a concentric circle of the first circle and has a different radius from that of the first circle into N (N is natural number of 2 or more) at intervals, and M and N are different from each other and a greatest common divisor of M and N is 1.