Nanometer level resolution can be achieved on measurements on highly reflective surfaces using a blue laser triangulation sensor.
Micro-Epsilon has launched a high precision blue laser triangulation sensor designed specifically for measurements on highly polished, reflective, shiny and mirrored targets with a resolution down to 30 nanometres.
The optoNCDT 2300-2DR (Direct Reflection) blue laser sensor with integrated controller benefits from an extremely small laser spot size (diameter 8.5 x 11µm) that enables measurements against very small objects. The sensor is ideal for precise distance measurements against highly polished, shiny or mirrored surfaces. The sensor can also measure distance and thickness of transparent targets such as optical glass.
Unlike conventional laser triangulation sensors, the optoNCDT 2300-2DR blue laser light operates by direct reflection rather than diffuse reflection. However, the design of the sensor housing is similar to a conventional laser sensor, which means the sensor body can be mounted parallel to the measurement object, which greatly simplifies the installation process.
Due to the shorter wavelength blue laser diode (405nm), the measurement signal is extremely stable, enabling the sensor to measure reliably to nanometre resolution. The shorter wavelength also means there is less “speckling” on the CCD line, again resulting in higher stability and accuracy of measurements.
The system is configured using an integrated web browser that is addressed to an Ethernet interface. This interface enables the user to make settings for the processing of measured values and signals, for example, peak selection, filtering and scaling the measurement range. Data can also be output via this interface, which simplifies sensor setup, configuration and diagnostics. The optoNCDT 2300-2DR has a measuring range of 2mm and a measuring rate that is adjustable up to 49kHz, allowing the measurements of dynamic, high speed processes. Data output is via Ethernet, RS422 or EtherCAT. If the sensor is operated with the C-Box/2A signal processing unit from Micro-Epsilon, an analogue output is also available.
Chris Jones, Managing Director at Micro-Epsilon UK comments: “Due to its shorter wavelength, the optoNCDT 2300-2DR performs better on highly polished, shiny or mirrored surfaces. A red laser light would be distorted by the shiny surface, resulting in a “speckle” effect. This would produce increased signal noise on the detector and therefore a loss of measurement accuracy. In contrast, the shorter wavelength of the blue laser sensor and extremely small spot size means it performs reliably with much less speckling, resulting in much lower noise levels, typically by a factor of two to three compared to red laser sensors.”