In the field of industrial automation, laser displacement sensors are widely used in dimensional measurement, positioning control, and appearance inspection due to their high accuracy, fast response, and non-contact measurement advantages. Based on different measurement methods, point laser and line-scan laser sensors are two common types. Today, let’s follow Weld Navigator® to learn how to choose between point and line-scan laser displacement sensors for real-world applications.
1. Difference in Working Principle
A point laser displacement sensor uses the laser triangulation principle. It projects a single laser spot onto the surface of an object, and the sensor calculates the distance by detecting the change in the position of the reflected light. It measures one point at a time, featuring a simple structure, high accuracy, and fast response speed.
A line-scan laser displacement sensor, on the other hand, emits a laser line and simultaneously captures height information along the entire line on the object’s surface, forming a profile line. By moving either the sensor or the workpiece, it can generate a complete 3D shape of the object, making it suitable for surface contour and cross-section measurements.
2. Advantages and Application Scenarios
Advantages of Point Laser Displacement Sensors
-
High accuracy, fast response, and easy installation
-
Compact design with relatively low cost
-
Suitable for single-point distance, height, thickness, and displacement measurements
Typical applications include:
Part height detection, thickness measurement, plane positioning, assembly gap inspection, and robotic alignment.
Advantages of Line-Scan Laser Displacement Sensors
-
Captures multiple data points simultaneously to form a surface profile
-
Detects complex surface shapes and contour deviations
-
Ideal for large-area, curved, or 3D surface measurements
Typical applications include:
Sheet contour inspection, weld seam tracking, shape measurement, surface defect detection, and 3D scanning.
3. Selection Recommendations
Choosing the right laser displacement sensor depends primarily on the measurement target and application requirements.
-
For single-point distance or displacement detection, a point laser sensor is the better choice.
-
For obtaining an entire profile or 3D shape, the line-scan laser sensor offers greater advantages.
-
For high-speed measurements or limited installation space, the point laser design provides better stability.
-
For complex surface inspection or shape analysis, the line-scan solution performs better.
In general, point laser sensors offer higher cost-performance, while line-scan sensors are more expensive but deliver richer 3D data output.
It’s recommended to evaluate factors such as measurement range, accuracy, response speed, installation space, and budget, and conduct sample testing if possible to determine the best fit.
4. Conclusion
When selecting a sensor, it is essential to clarify your measurement objectives. Point laser displacement sensors focus on precision and speed for single-point detection, while line-scan laser displacement sensors excel at contour and shape measurement. The two are complementary technologies, each suited for different inspection needs.
Regardless of the type, a high-quality laser displacement sensor should offer high stability, ease of use, and strong anti-interference performance to ensure optimal results in modern industrial environments.
