Optical Encoder Reference Signal Generation
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Solution Overview
Problem
Existing optical encoders face challenges in consistently generating a reference signal with constant width and timing, as previously disclosed techniques fail to ensure stability in these parameters.
Innovation Solution
The method involves a reference signal generation process for an optical encoder, where a detection head with first and second light-receiving elements, arranged in parallel, adjusts output signals to equalize levels at specific phases, generating a reference signal that starts and ends at predetermined timing based on these adjustments, ensuring a constant width and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the width and timing of the reference signal are adjusted by changing the amplification factor, then the reference signal can be customized to different requirements, but the width and timing become unstable and vary between adjustments
Solution Approach 1:
The patent changes the control parameter from amplification factor to light-receiving element position. By moving the light-receiving elements along the scale, the reference signal width and timing are adjusted while maintaining stability, as the positional relationship between the light-receiving elements and the scale pattern directly determines the signal characteristics without requiring amplification adjustments
Solution Approach 2:
The patent replaces the electrical adjustment method (changing amplification factors in signal processing circuits) with a mechanical adjustment method (physically positioning the light-receiving elements). This substitution eliminates the instability introduced by electrical amplification while maintaining the ability to adjust reference signal characteristics
2Adaptability or versatility
If the amplification factor is adjusted to change reference signal characteristics, then flexibility is improved, but measurement precision deteriorates due to instability
Solution Approach 1:
The patent changes the controlled parameter from signal amplification to light-receiving element position. This ensures that reference signal characteristics are determined by precise mechanical positioning rather than electrical amplification, thereby maintaining measurement precision while providing flexibility in signal generation
Solution Approach 2:
The patent performs preliminary positioning of the light-receiving elements to establish the desired reference signal characteristics before signal detection begins. This preliminary action ensures that the reference signal width and timing are correctly set without requiring subsequent amplification adjustments that could affect 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 approach stabilizes the generation of a reference signal with consistent width and timing, enhancing the accuracy and reliability of the optical encoder's position detection.
Implementation Method 1
a light source that emits light to the scale; a first light-receiving element and a second light-receiving element which receive light emitted from the reference point detection pattern when light is irradiated on the reference point detection pattern by the light source
Data Source
AI summary
First and second output signals are generated based on amounts of light received by first and second light-receiving elements, respectively, when a detection head is moved along a scale; a first amplitude adjustment is performed to adjust an amplitude of the first or second output signal such that levels of first and second output signals become equal at a first reference phase; a second amplitude adjustment is performed to adjust an amplitude of the first or second output signal such that levels of the first and second output signals become equal at a second reference phase; and a reference signal that starts at a timing when levels of the second output signal and the first output signal subjected to the first amplitude adjustment become equal and ends at a timing when levels of the second output signal and the first output signal subjected to the second amplitude adjustment become equal.