Optical Encoder Alignment Photodiodes Assembly Tolerance
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Solution Overview
Problem
Conventional optical encoders face accuracy degradation due to position deviations during assembly and installation, which can be costly to mitigate through tighter control methods.
Innovation Solution
The implementation of two additional alignment photodiodes that record and adjust output signals to match a pre-stored reference pattern, ensuring accurate position alignment between elements without requiring stringent assembly control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tighter assembling and installation control is implemented to reduce position deviation, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies preliminary action by pre-storing a reference pattern that represents the ideal alignment state of the optical encoder elements. During operation, the system compares current alignment patterns against this pre-stored reference to detect and correct position deviations, eliminating the need for tight assembly control while maintaining measurement precision
Solution Approach 2:
The patent implements feedback by continuously monitoring the alignment pattern of optical elements and comparing it with the pre-stored reference pattern. When deviations are detected, the system provides feedback signals that enable real-time correction of element positions, maintaining accuracy without requiring precise initial assembly
2Ease of operation
If alignment photodiodes are added to enable position calibration, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the optical encoder to automatically calibrate its own element positions using the alignment photodiodes and pre-stored reference pattern. The system performs self-diagnosis and self-correction without requiring external intervention or complex alignment procedures, improving ease of operation while keeping the added complexity minimal
Solution Approach 2:
The patent uses copying by creating a reference pattern that represents the ideal alignment state and storing it in memory. This reference copy is then used to compare against actual alignment patterns during operation, enabling simple and effective position calibration without complex mechanical alignment mechanisms
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 enables low-cost, effective alignment of optical encoder elements, maintaining accuracy while reducing the need for precise installation procedures.
Implementation Method 1
The photodiodes 15 detect light emitted from the light source 11
Implementation Method 2
Each of the first photodiode and the second photodiode is covered by a triangular-shaped opaque material at one corner thereof
Data Source
AI summary
There is provided an optical encoder with alignable relative positions between elements including an encoding medium, a sensor package and a memory. The sensor package includes a photodiode array and two alignment photodiodes opposite to the encoding medium. The memory records an alignment pattern associated with output signals of the two alignment photodiodes when the encoding medium and the sensor package are at nominal operating positions. When the encoding medium and the sensor package are not at the nominal operating positions, the relative position alignment is performed by adjusting current relative positions between the encoding medium and the sensor package to cause a current pattern associated with output signals of the two alignment photodiodes to be identical to the alignment pattern.