These Sensors can be used to measure
distances and heights. A wide variety of models is available, including
Laser Sensors, LED Sensors, Ultrasonic Sensors, Contact Sensors, Eddy
Current Sensors, and more.
Principle of Measurement of the Optical Displacement Sensor
Light from the light source is condensed by the lens and directed onto the
Light reflected from the object is condensed onto a one-dimensional
position sensing device (PSD)* by the receiving lens. If the position of
the object (the distance to the measuring device) changes, the image
formation positions on the PSD will differ, and if the balance of the two
PSD outputs changes, the image formation positions on the PSD will differ
and the balance of the two PSD outputs changes.
If the two outputs are A and B, calculate A/(A + B) and use appropriate
values for the span coefficient "k" and the offset "C".
can be obtained.
The value measured is not the illuminance (brightness), but the two output
displacements A and B, and thus even if the received light intensity
changes because the distance to the object changes, the result is not
affected and linear output proportional to the distance difference and
position shift is obtained.
Optical System of the Displacement Sensor
Regular reflection model
Light from the object is directly received by regular reflection, and
stable measurement is possible of metal and other objects with a glossy
Diffuse reflection model
A light beam is projected perpendicularly onto the surface of the object,
and the diffuse light that is reflected back is received for a wide
Measurement Sensor Glossary
This is the width, expressed in terms of the
distance, of the fluctuation in the linear output when the measured object
Error with respect to ideal straight line of
linear output Normally the percentage of the measurement range (full
scale: FS), expressed in the format "1%".
The amount of variation of linear output
with respect to changes in the ambient temperature.
Normally the percentage of the measurement range (full scale: FS),
expressed in the format %FS/°C.
Example: 0.03%FS/°C (FS = 20 mm)
Linear output when the displacement and
width of the object are changed to steps.
In analog output, the time required for 10% to 90% change is expressed in
terms of the "response time".
Response time and resolution
In general the displacement, response time,
and resolution are correlated as shown in the following diagram.
When you wish to precisely measure
displacement, select a slower response time setting. (This reduces
When you need a fast response, select a
faster response time setting. (This reduces the resolution.)
Smart Sensor (Laser
Ensure stable measurement regardless
of workpiece color and material, on even fast-moving objects.
Smart Sensors (2D CMOS
Precise spot detection, wide-range
detection and long-distance detection.
2D Profile Measuring
Ultra wide laser beam and super