Deflector System X-Coordinate Measurement via Lambda/2 Signal Inversion
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Solution Overview
Problem
Current methods for measuring coordinates in deflector systems are limited to one-dimensional measurements along the micro sweep direction, making it difficult to achieve accurate two-dimensional measurements without significant hardware modifications or increased noise.
Innovation Solution
A software-based method that rotates the measurement approach 90 degrees, utilizing the micro sweep as a light source and the lambda/2 signal as a reference to calculate X-coordinates with high accuracy, without requiring new hardware, by generating images of patterns and using cursors to define pixel averages and center of gravity calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If special patterns containing 45-degree bars are used to measure X-coordinates, then measurement capability in X-direction is achieved, but device complexity and calibration difficulty increase
Solution Approach 1:
Instead of using complex 45-degree bar patterns to measure X-coordinates, the patent inverts the approach by rotating the measurement method 90 degrees and using the lambda/2 signal (which naturally provides X-direction information) as the reference. This simplifies the pattern requirement to basic vertical bars while maintaining measurement capability.
Solution Approach 2:
The patent utilizes the lambda/2 signal, which is already generated by the existing deflector system, to serve as the reference for X-coordinate measurement. This eliminates the need for external reference signals or complex pattern designs, as the system uses its own internal signal for measurement.
2Measurement precision
If measurement clock frequency is increased to improve time measurement resolution, then measurement precision improves, but noise and system requirements increase
Solution Approach 1:
The patent changes the fundamental measurement parameter from time-based measurement (requiring high-frequency clocks) to phase-based measurement using the lambda/2 signal. This parameter change allows achieving high resolution without increasing clock frequency, thereby avoiding associated noise and system complexity.
Solution Approach 2:
The patent utilizes the periodic nature of the lambda/2 signal to perform measurements at multiple phases across the signal period. By accumulating measurements from different phases, the system achieves high precision without requiring a single high-frequency measurement clock, thus reducing noise.
3Ease of operation
If one-dimensional measurement method is used along micro sweep direction, then measurement simplicity is maintained, but measurement versatility is limited
Solution Approach 1:
The patent adds a second measurement dimension by utilizing the lambda/2 signal for X-coordinate measurement while maintaining the micro sweep for Y-coordinate measurement. This dimensional extension is achieved through software processing without adding physical measurement axes, preserving simplicity while enhancing versatility.
Solution Approach 2:
The patent makes the measurement system universal by enabling it to measure both X and Y coordinates using the same detection hardware. The lambda/2 signal is utilized to provide X-direction measurement capability, making the system multi-functional without requiring separate measurement systems for different directions.
Data Source
AI summary
The present invention relates to a method for determining the coordinates of an arbitrarily shaped pattern in a deflector system. The method basically comprises the steps of: moving the pattern in a first direction (X), calculating the position of the edge of the pattern by counting the number of micro sweeps, performed in a perpendicular direction (Y), until the edge is detected, and determining the coordinates by relating the number of counted micro sweeps to the speed of the movement of the pattern. The invention also relates to software implementing the method.