Optical Encoder Gain Regulation for Index Pulse Width Stability
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Solution Overview
Problem
Conventional optical encoders experience fluctuations in light intensity and pulse width of index output due to varying longitudinal distances, leading to decreased calculation accuracy and identification precision.
Innovation Solution
Incorporating additional control photodiodes and a regulation control circuit to adjust the gain of the index output signals, ensuring a consistent pulse width by turning on or off gain regulation based on control signals from the control photodiodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If emission light intensity of the light source is adjusted to keep position photodiode output identical, then position measurement accuracy is improved, but index photodiode output varies significantly
Solution Approach 1:
The patent uses feedback control by introducing control photodiodes that detect light intensity and generate control signals. These signals are fed to a regulation control circuit that adjusts the gain of the index photodiode output through a gain control circuit, creating a closed-loop system that maintains stable index output despite variations in light intensity.
Solution Approach 2:
The patent changes the gain parameter of the index photodiode output dynamically. When light intensity varies, the regulation control circuit adjusts the gain value to compensate, ensuring that the index output remains within a predetermined range regardless of light intensity changes.
2Adaptability or versatility
If longitudinal distance between substrate and code disk varies, then assembly flexibility is improved, but light intensity and pulse width stability deteriorate
Solution Approach 1:
The control photodiodes provide feedback about light intensity variations caused by longitudinal distance changes. The regulation control circuit uses this feedback to adjust the gain of the index output, compensating for the effects of distance variation and maintaining measurement precision across different assembly configurations.
Solution Approach 2:
The patent introduces dynamic gain adjustment capability that adapts to varying longitudinal distances. The gain control circuit can change its amplification factor in real-time based on the detected light intensity, allowing the system to maintain performance across a range of distances rather than being optimized for a single fixed distance.
3Stability of the object's composition
If gain regulation is applied to index photodiode output, then pulse width consistency is improved, but system complexity increases
Solution Approach 1:
The patent segments the control function into separate modules: control photodiodes for detection, regulation control circuit for decision-making, and gain control circuit for execution. This segmentation allows each component to perform a specific function, making the overall complex system more manageable and maintainable while achieving pulse width consistency.
Solution Approach 2:
The regulation control circuit acts as an intermediary between the control photodiodes and the gain control circuit. It processes the control signals from the photodiodes and generates appropriate regulation signals for the gain control circuit, providing a buffer that simplifies the interaction between detection and execution components.
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
Maintains a consistent index pulse width and keeps the index output within a predetermined range, enhancing the accuracy and reliability of the optical encoder's performance across different longitudinal distances.
Implementation Method 1
The substrate includes a position photodiode and an index photodiode... light intensity of light reflected by the code disk to the position photodiode becomes lower... light intensity of light reflected by the code disk to the index photodiode
Implementation Method 2
The gain control circuit is configured to amplify the index signal using a gain... the regulation control circuit is configured to turn on or turn off gain regulation of the gain control circuit
Data Source
AI summary
There is provided an optical encoder including an encoding medium and a substrate. The encoding medium has a relative movement with respect to the substrate in a predetermined direction. The substrate includes an index photodiode and two control photodiodes. The index photodiode is arranged between the two control photodiodes along the predetermined direction. The output signals of the two control photodiodes are for controlling ON/OFF of gain regulation on an output signal of the index photodiode so as to turn on the gain regulation within an interval during which the index photodiode does not generate an index pulse but to turn off the gain regulation within an interval during which the index photodiode generates the index pulse.