Guide Rail Measurement Scale Microstructure for Bright-Field Encoding
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Solution Overview
Problem
Existing measurement scales for linear encoders have low contrast sensor signals, leading to inadequate detection of position changes and interpolation accuracy, particularly when using the bright field measurement principle, which is problematic for linear profile rail guides.
Innovation Solution
A method for applying a measurement scale to a guide rail using a pulsed laser to create microstructures on the surface, resulting in high-contrast marking regions that absorb light and allow for reliable position detection through bright field measurement by introducing nano-scale elevations with ultra short-pulse lasers, ensuring corrosion resistance and high viewing angle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement scales with scattering regions are used, then position changes can be detected, but the sensor signal contrast is low leading to inadequate detection accuracy
Solution Approach 1:
The patent applies black chromium coating to create marking regions with high light absorption contrast. The marking regions are coated with black chromium layer that absorbs light, while mirror regions remain reflective. This creates high contrast between marking and mirror regions, enabling reliable bright field measurement with sufficient signal discrimination for accurate position detection.
Solution Approach 2:
The patent uses laser beam scanning to create periodic microstructures on the surface. The laser beam is scanned across the guide rail surface in a controlled manner, creating regular patterns of marking regions with high precision. This mechanical scanning process ensures consistent spacing and geometry of the measurement scale features.
2Ease of operation
If bright field measurement principle is used, then position detection is simplified, but existing scales produce insufficient contrast for reliable detection
Solution Approach 1:
The black chromium coating provides high light absorption in the visible spectrum, creating dark marking regions that strongly contrast with the bright reflective mirror regions. This optical contrast enhancement enables the bright field measurement principle to function effectively, where the sensor detects light intensity variations as the scale passes by, achieving both operational simplicity and measurement precision.
Solution Approach 2:
The measurement scale combines different surface treatments on the same substrate: mirror regions with polished reflective surfaces and marking regions with black chromium coating. This composite structure of different material finishes on the steel guide rail surface creates the necessary optical contrast while maintaining a single integrated component.
3Area of stationary object
If laser beam scans the entire surface, then complete coverage is achieved, but processing time increases
Solution Approach 1:
The laser processing is divided into discrete marking regions rather than treating the entire surface uniformly. The laser beam scans only specific segments of the guide rail surface where marking regions are required, leaving mirror regions untreated. This segmented approach processes only the necessary areas, reducing total processing time while achieving complete coverage of required marking zones.
Solution Approach 2:
The laser beam scanning follows a periodic pattern, moving back and forth across the guide rail surface to create regularly spaced marking regions. This periodic scanning motion efficiently covers the required area with systematic passes, optimizing the balance between coverage and processing time through rhythmic, repetitive motion patterns.
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
The method enhances the contrast and accuracy of position detection in linear encoders, improving the reliability of position measurement in linear profile rail guides by creating microstructured surfaces that absorb light effectively, thereby increasing the accuracy of position determination.
Implementation Method 1
The laser beam is directed at the first region of the first side surface in such a way that only a subregion of the first region is irradiated by means of each individual light pulse
Implementation Method 2
the first side surface in the subregion of the first region, which is irradiated by means of the respective individual light pulse, is changed due to the irradiation
Implementation Method 3
marking regions, wherein each of the marking regions extends in a line-like manner transverse to the longitudinal direction of the at least one track... that absorb light
Data Source
AI summary
A method for applying a measurement scale to a guide rail surface of a linear profile rail guide, the guide rail having a first side surface and the measurement scale including at least one track extending linearly and longitudinally toward the guide rail, including several mirror regions arranged alternately one behind the other, and marking regions, uses a pulsed laser to generate a laser beam and introduces a microstructure in a first region corresponding to the at least one marking region of the first side surface. The laser generates the laser beam with a sequence of several light pulses that is directed at the first region so that the laser beam is moved two-dimensionally relative to the first region to irradiate different subregions of the first region one after the other by the light pulses. Each different irradiated subregion has an overlap with at least one other irradiated subregion.