What Is a Laser Distance Meter?
Laser distance meters are used for non-contact, high-precision distance measurement using laser light.
They use a visible laser with a wavelength of several hundred nanometers, enabling measurement with a high resolution of sub-micrometers. A laser beam is irradiated onto a corner cube attached to the sample, and the distance to the sample is measured by analyzing the phase difference of the reflected laser beam.
Laser distance meters are also available with optional software to measure the speed, acceleration, and displacement of the sample.
Uses of Laser Distance Meters
Laser distance meters are used for equipment that requires high-precision positioning, such as semiconductor, electrical, and electronic manufacturing equipment. They can also be used to measure the speed and position of chip mounters and printer heads that move at high speeds because they use light.
In addition, by using two laser distance meters to measure the distance between different locations on a moving part simultaneously, such as the stage of a device, it is possible to check for pitching or yawing of the stage and displacement within the same device.
Principle of Laser Distance Meters
The laser distance meters calculates the distance from the phase difference of the laser beam that is irradiated onto the sample and bounced back.
A small, lightweight corner cube is attached to the sample to reflect the laser beam. The laser light is irradiated onto this cube and the reflected light is analyzed.
Since the reflected light has a phase difference with respect to the projected light, interference occurs between these lights. Since the phase difference changes depending on the distance, the distance can be determined by analyzing the interference results.
The wavelength of the laser light is about 600 nanometers, and the measurement accuracy is very high at sub-micrometers.
Dynamic information, such as sample velocity, acceleration, and displacement, can also be obtained by fine-tuning the sampling pitch of the laser beam.
Some devices can sample at a period of up to 1 megahertz, making it possible to measure the speed of devices that move at high speeds or repeatedly move in minute, precise increments.
Types of Laser Distance Meters
There are various types of laser distance meters, depending on the application.
1. Laser Rangefinder
A typical laser distance meter is used to measure distances from a single point. They come in a variety of sizes, from palm-sized hand-held models to larger ones with a measuring range of several kilometers. They are commonly used on construction sites and in surveying.
2. Laser Interferometer
A laser interferometer is a device that uses interference of laser beams to measure distance. It splits the laser beam and detects minute changes in distance due to interference. It has extremely high measurement accuracy and is suitable for measuring minute displacements on the nanometer scale. It is used in fields such as microfabrication and optical device evaluation.
3. Laser Multi-Point Rangefinder (Laser Tracker)
A laser tracker is a device that measures the position and shape of an object by irradiating a laser beam onto the object and receiving the reflected light from multiple photosensors. It is mainly used in the industrial field to measure the position and shape of an object in machining and automobile manufacturing.
4. Laser Vibrometer
A laser vibrometer is a device that irradiates a laser beam onto an object and measures vibration and displacement based on the reflected light. It has extremely high measurement accuracy and is used for vibration analysis of machinery and evaluation of materials.
5. Laser Positioning System (Laser Tracking System)
These devices use laser beams to track the position and velocity of objects or moving objects. They are used in aerospace, robotics, motion capture, and other fields requiring high-speed, precise position measurement.