What are Displacement Sensors (Displacement Gauges) and Dimension Measurement Systems?

Displacement sensors (displacement gauges) are used for a wide range of purposes. Below are a few examples.

There are several types of displacement sensors; most sensors cover a broad range of applications, while others are more specialized.
For example, inductive displacement sensors detect changes in electromagnetic fields they emit each time they come in close proximity to a metallic object.
Contact displacement sensors measure the contact probe's displacement and position by using light, CMOS sensors, and encoders.
Laser displacement sensors are incredibly versatile, as they can measure displacement (and various derivative measurements) across a variety of different materials… including transparent ones.
Laser profilers measure displacement or height using a laser line to determine a 2D/3D profile of an object's surface.

How is displacement measured? Laser displacement gauges work by emitting a laser beam onto a target surface and calculating the appropriate metrics depending on the sensor type. Laser triangulation displacement sensors work by detecting the angle of the reflected light, which is then analyzed and used to calculate displacement.
Time-of-flight laser displacement gauges, as their name implies, calculate the time it takes for light to return from the moment it’s been emitted toward the target, using the speed of light to calculate distance. Confocal sensors, however, analyze the wavelength of the reflected light, which varies with distance, to determine displacement.
All these methods, though offering similar results with an exceptionally high level of accuracy, differ in their working principles and, thus, in their applications across numerous industries.

The units of displacement measurement also depend on the application and the level of precision a specific application requires. For general industrial applications, millimeters or inches are the most common displacement measurement units employed.
However, extremely precise measurements—such as the positioning of components in the semiconductor industry—might require measurements in the micrometer or even nanometer range.
Ultimately, the unit of measurement is a critical factor to consider when selecting a laser displacement sensor, as it directly affects the sensor’s adequacy.

As stated above, laser displacement sensors are found in a wide range of industrial applications thanks to their accuracy, which is often in the single-digit µm range, their reliability, and their non-contact nature, which allows them to precisely measure even the most fragile of objects.
These sensors are most commonly used in the automotive industry for quality control, ensuring that components and applications are manufactured precisely and within specified tolerances. In electronics manufacturing, these sensors are often used to measure wafer thickness and component placement.
Laser displacement gauges are also used in robotics for precise positioning, in material handling systems to measure and detect objects, and in construction for monitoring structural displacements. The broad scope of their applications across various industries only attests to the versatility of laser displacement gauges and their importance when conducting precise displacement measurements.
KEYENCE offers a comprehensive range of different displacement measurement sensors. If you want to learn more, contact us today. We have plenty of resources to help you choose the best possible integration for your current production and dimension measurement system.