Step Height Measurement

The distance to the location where the laser is reflected is measured to high precision.

A 1D laser displacement sensor is a reflective type sensor, which means it emits light to the surface of the measured object. That light is then reflected back to the light receiver in the sensor. Based on the changes in distance between the object and the sensor, the sensor can determine the step height measurement. High-accuracy displacement sensors are grouped into two basic categories: confocal and laser triangulation.

Confocal Displacement Sensor CL-3000 Series

High-precision measurement on all targets, with simple sensor head installation and program settings. CL-3000 Series ultra-compact coaxial laser displacement sensors address manufacturing challenges such as improving quality, preventing the shipment of defective parts and increasing production.
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• Multi-color confocal method
• Linearity：From ±0.2 µm
• Confocal displacement sensor

Micro-head Spectral-interference Laser Displacement Meter SI-F Series

Introducing the world’s first micro-head, with the highest measurement accuracy in its class and a level of performance that was previously thought impossible. These micro-head sensors can be used to measure the thickness and warpage of high-precision objects such as silicon wafers.
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• Spectral interference method
• Ultra-high resolution of 1 nm
• 2 mm microprocessor sensor head

2D laser displacement sensors use reflected light displacement to calculate distances between the sensor and the surface of the part. Similar to 1D laser displacement, 2D relies on the laser triangulation methods to quantify step measurements.

A profile of the surface is obtained where the laser line hits, making it possible to acquire relative measurements such as step height. Even if the target is tilted, step can be measured accurately because the sensor head features an alignment adjustment function.

2D/3D Laser Profiler LJ-X8000 Series

LJ-X laser profilers collect height data across a laser line rather than a single point. This enables 2D/3D measurements such as height difference, width, or angle to be performed using a single sensor.
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• 2D triangulation method
• In-line multi-point measurement
• World's fastest sampling rate at 64,000 images/sec

Confocal Displacement Sensor CL-3000 Series

High-precision measurement on all targets, with simple sensor head installation and program settings. CL-3000 Series ultra-compact coaxial laser displacement sensors address manufacturing challenges such as improving quality, preventing the shipment of defective parts and increasing production.
Click here for more details

• Multi-color confocal method
• Linearity：From ±0.2 µm
• Confocal displacement sensor

2D optical micrometers are typically comprised of a light emitter and light receiver, with the system employing high-intensity LEDs and telecentric lenses to focus the beam of light onto a high-speed CMOS sensor and capture images in the full field of view. When an object whose step height we're measuring obstructs the light beam, it casts a shadow or a silhouette onto the CMOS sensor, which picks it up and converts it into data that is processed by the measurement devices' internal systems and associated software.

Telecentric Measurement System TM-X5000 Series

TM-X optical micrometers are thrubeam sensors that measure any object that blocks the light passing from the transmitter to the receiver. These sensors are designed without moving parts to provide accurate measurements without regular maintenance.
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2D telecentric optical method. Simultaneous measurement of up to 100 with calibrated high-speed measurement.

The distance to the location where the laser is reflected is measured to high precision.

Depending on your system of choice, you can connect one, two, or more laser displacement sensors to a single controller and have them take measurements in sync. This will provide you with an option to collect more comprehensive step height measurement data. It's worth noting that some systems support up to four laser displacement sensors, which is great for measuring step height on larger objects, such as a vehicle.

To efficiently measure the height of a single point, use a reflective laser displacement sensor. You can measure height at multiple locations by communicating across multiple sensors or by scanning over the target with one sensor.

Confocal Displacement Sensor CL-3000 Series

High-precision measurement on all targets, with simple sensor head installation and program settings. CL-3000 Series ultra-compact coaxial laser displacement sensors address manufacturing challenges such as improving quality, preventing the shipment of defective parts and increasing production.
Click here for more details

• Multi-color confocal method
• Linearity：From ±0.2 µm
• Confocal displacement sensor

Micro-head Spectral-interference Laser Displacement Meter SI-F Series

Introducing the world’s first micro-head, with the highest measurement accuracy in its class and a level of performance that was previously thought impossible. These micro-head sensors can be used to measure the thickness and warpage of high-precision objects such as silicon wafers.
Click here for more details

• Spectral interference method
• Ultra-high resolution of 1 nm
• 2 mm microprocessor sensor head

If the target is a transparent object or an object with a mirror-finished surface, you have to install the sensor head tilted at an angle that is half the angle of the projected and received light, α, in relation to the target, as shown in figure 2. (When using the triangulation method.)

Also, if the target is a transparent object, a key point for stable measurement is to have the transparent object be at least as thick as a certain value. If the object is thin, the value measured for the front surface height may be lower than it should be due to the effect of the light reflected from the back surface of the transparent object.
The minimum thickness limits that ensure stable measurement vary depending on the sensor head type, the transparency of the target, and the reflectivity of the back surface.

If at least one of the surfaces being measured in the step measurement is a transparent object or an object with a mirror-finished surface, install the sensor head tilted at an angle that is half the angle of the projected and received light, α, in relation to the target, as shown in figure 4.
It is also necessary to prepare a head that is dedicated for use with transparent objects and objects with mirror-finished surfaces. Furthermore, if the target is a transparent object, it must be at least as thick as a certain value in order for the surface height to be measured accurately.

If the object is thin, the value measured for the front surface height may be lower than it should be due to the effect of the light reflected from the back surface of the transparent object. The minimum thickness limits that ensure stable measurement vary depending on the sensor head type, the transparency of the target, and the reflectivity of the back surface.

When the probe comes into contact with a soft target, the target can be compressed, which leads to a corresponding measurement error. Additionally, objects that are particularly soft or even fragile could suffer surface damage, which will impede step measurement.

With non-contact measurement, it is possible to measure targets that deform, such as soft targets and liquid surfaces.

For targets that are thin and light, it is necessary to hold down the target to ensure that it does not float on an air gap in order to accurately measure the surface height.

With contact measurement, the probe presses down on the target surface, which eliminates errors caused by the target floating in the air. For this reason, the contact method is better suited to this type of measurement than the non-contact method.

Contact measurement methods and associated tools are often quite hefty, which poses a challenge when measuring step height in the micron and nanometer range. With a non-contact laser displacement sensor, the measurement spot (which ranges from a few micron to hundreds of microns in size) is generally smaller than the probes used in contact measurement. This makes it possible to accurately measure the base height of more narrow indentations with the non-contact method.