Optical Encoder Pattern Intervals for Harmonic Removal
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Solution Overview
Problem
Conventional optical encoders fail to effectively remove harmonics from electric signals used for precise position detection, leading to manufacturing errors and reduced signal quality.
Innovation Solution
The optical encoder employs first and second patterns aligned at specific intervals, where the interval of the first pattern is a fraction of its width, allowing for the reliable removal of harmonic waves, including 2nd, 3rd, 4th, 6th, and 12th harmonics, by adjusting the width and interval of the patterns to maximize signal efficiency and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical encoder patterns are used with standard intervals, then the device structure is simple and manufacturing is easier, but harmonic waves cannot be effectively removed leading to reduced measurement precision
Solution Approach 1:
The patent applies parameter changes by modifying the interval between encoder patterns from standard equal spacing to specific fractional intervals (1/6, 1/4, 1/3 of pattern width). This parameter adjustment enables selective removal of harmonic waves (2nd, 3rd, 4th, 6th, and 12th harmonics) while maintaining position detection precision, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent segments the encoder pattern into multiple distinct intervals with different spacing ratios. By dividing the pattern width into specific fractions (1/6, 1/4, 1/3) for different pattern intervals, the system creates segmented spacing that targets specific harmonic frequencies for removal, thereby improving measurement precision without excessive complexity
2Measurement precision
If pattern interval is increased to remove harmonics, then harmonic removal effectiveness improves, but light receiving area utilization decreases
Solution Approach 1:
The patent optimizes the balance between harmonic removal and light receiving efficiency by changing the interval parameters to specific fractions (1/6, 1/4, 1/3 of pattern width) rather than uniform spacing. These optimized parameters achieve effective harmonic removal while maintaining compact pattern density that preserves light receiving area utilization
Solution Approach 2:
The patent applies partial action by selectively targeting specific harmonic frequencies (2nd, 3rd, 4th, 6th, 12th) for removal through specific interval configurations, rather than attempting to remove all harmonics. This selective approach achieves sufficient measurement precision while maintaining better light receiving efficiency compared to aggressive interval expansion
3Measurement precision
If multiple patterns with different intervals are used to remove various harmonics, then harmonic removal comprehensiveness improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ratios (1/6, 1/4, 1/3 of pattern width) for pattern intervals that target multiple harmonic frequencies simultaneously. These standardized parameter ratios simplify manufacturing by providing clear design guidelines, reducing the actual precision burden compared to arbitrary complex spacing arrangements
Solution Approach 2:
The patent creates multi-functional pattern intervals where single interval configurations serve multiple purposes: the 1/6 interval removes 2nd, 3rd, 4th, 6th, and 12th harmonics; the 1/4 interval removes 2nd and 4th harmonics; the 1/3 interval removes 3rd harmonic. This multi-functionality achieves comprehensive harmonic removal while simplifying manufacturing by using standardized ratio-based designs
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 the optical encoder's ability to remove harmonics, reduces manufacturing errors, and improves signal quality by efficiently utilizing the light receiving area, thereby enhancing the precision and reliability of position detection.
Implementation Method 1
The optical sensor focuses on a surface of the encoder pattern. As the sensor moves with respect to the encoder pattern, or the encoder pattern moves with respect to the sensor, the sensor reads a pattern of light either transmitted therethrough, or reflected by, the encoder pattern to detect the motion or position.
Implementation Method 2
The optical sensor focuses on a surface of the encoder pattern. As the sensor moves with respect to the encoder pattern, or the encoder pattern moves with respect to the sensor, the sensor reads a pattern of light either transmitted therethrough, or reflected by, the encoder pattern to detect the motion or position.
Data Source
AI summary
The optical encoder according to the present disclosure includes a light receiving part formed with a plurality of first patterns, and a scale formed with second patterns and moving relative to the light receiving part, where at least one of the first and second patterns is aligned at a same interval to remove harmonic waves.