Compact Edge Detection for Sapphire Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing edge detection methods for transparent workpieces like sapphire substrates are inefficient due to bulkiness and difficulty in installing detection devices on laser beam processing machines, as they require beam oscillation at an angle, making them cumbersome and hard to integrate.
Innovation Solution
A compact edge detection device using a beam oscillation mechanism that oscillates the detection beam to be parallel to the objective lens's center axis at a position offset, allowing the reflected light detection to differentiate between light reflected from the workpiece and non-existent areas, enabling accurate edge detection without the need for angled beam oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection beam is applied at an angle to detect edges of transparent workpieces, then edge detection accuracy is improved, but the detection device becomes bulky and difficult to install
Solution Approach 1:
Instead of oscillating the beam at an angle to the workpiece surface, the patent inverts the approach by oscillating the beam parallel to the optical axis of the objective lens while positioning the beam offset from the center. This inversion of the oscillation geometry allows achieving angle-dependent reflection detection without requiring angled beam delivery, thereby simplifying the device structure while maintaining edge detection accuracy for transparent workpieces
2Ease of operation
If a compact detection device is designed, then ease of installation is improved, but the ability to capture specular reflection from transparent surfaces may be compromised
Solution Approach 1:
The patent introduces the objective lens as an intermediary optical element that focuses the oscillated detection beam onto the workpiece surface. By using the lens's focal properties and its center axis as a reference, the system achieves effective angle-dependent reflection capture without requiring the beam delivery path to be physically angled, thus maintaining compactness while ensuring reliable specular reflection detection from transparent surfaces
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 solution allows for a compact edge detection system that can accurately detect workpiece edges, even on transparent materials, improving the integration and efficiency of laser beam processing machines by refracting the detection beam at an angle onto the workpiece surface, capturing specular reflection effectively.
Implementation Method 1
an objective lens for focusing the detection beam oscillated from the beam oscillation means
Implementation Method 2
the edges of the workpiece can be detected by applying the detection beam to the front surface of the workpiece at an angle and capturing a specular reflection light of the detection beam
Data Source
AI summary
A device for detecting the edges of a workpiece held on the chuck table of a processing machine, having a beam oscillation means for oscillating a detection beam, an objective lens for focusing the detection beam oscillated from the beam oscillation means, and a reflected light detection means for detecting the reflected light of the detection beam applied through the objective lens, wherein the beam oscillation means oscillates the detection beam in such a manner that the optical axis of the detection beam becomes parallel to the center axis of the objective lens at a position offset from the center axis; and the reflected light detection means detects the edge of the workpiece based on a positional difference between reflected light obtained when the detection beam applied through the objective lens is reflected on an area where the workpiece is not existent and refracted by the objective lens and reflected light obtained when the detection beam is reflected on the workpiece and refracted by the objective lens.