Uniform Laser Line Fundamentals
Major parameters of laser line are working distance, fan angle, line width, length of laser line, etc..
Major parameters
|
Model |
DLL-A-B-C-D DLL: category laser line, A: wavelength, B: output power, C: fan angle, D: Package type. e.g. DLL-405-050-10-L16 means laser line, 405nm, 50mW, 10° angle, phi16*79mm package. |
|
Wavelength |
405nm~1064nm available, other spectrums customizable. |
|
Spectral width (FWHM) |
Typical value: Diode laser 2nm, solid state laser 0.1~0.2nm, 1310nm/1470nm/1550nm lasers about10nm |
|
Output power |
As per requested |
|
Output Power stability (RMS) |
<3% over 2 hours (thermoelectrically cooled) <5% over 2 hours |
|
Fan Angle |
5°，10°，20°，30°，45°，60°，75°，90° available other angles customizable. |
|
Working distance |
As per requested |
|
Line width |
As per requested. The line width differs from dozens microns to several millimeters in different working distances. |
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Laser Line generators Type |
Uniform intensity distribution (generated by Powell lenses) Gaussian distribution (generated by cylindrical lenses) |
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Line Straightness |
Typical >1000:1, higher >3000:1, strict >5000:1 |
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Off-Axis Angle |
Angle between output laser and illuminated surface |
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Operating temperature |
Depended on the performance of laser diodes 0~40℃ or 0~60℃ typical |
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Warm up time |
The time needed for stabilizing of the laser output power |
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Dimensions: |
As per the specification |
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Laser Driver |
As per the specification |
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Power supply |
5VDC/12VDC/24VDC, 90-240VAC available |
|
Expected lifetime (MTTF) |
Related with laser types and working temperature. Solid state laser 5000hrs typical, Laser diode 10000~20000hrs typical |
|
Line Uniformity |
For uniform line: typical +/-30%，better +/-20% |
Wavelengths
|
Violet 375nm* 395nm* 405nm |
Blue 445nm 450nm 462nm*
|
Cyan 488nm |
Green 515nm 520nm 532nm* |
Yellow 561nm* 594nm* |
Red 635nm 640nm 650nm 660nm 670nm 730nm 750nm … |
IR 785nm 808nm 830nm 976nm 1064nm 1470nm* 1550nm* … |
Illustration of available wavelengths (*customization needed for Grey numbers)
Laser output power and power stability
Laser output power and stability are tested as following. The power stability can be calculated in two methods: P-P=（Max-Min）/Mean or RMS=Sigma/Mean.
Test of line width
Fan angle (line Length) is an important quality. Fan angle is defined at 80% intensity clip level. The working distance is best between 500mm to 1meter. Customization of other distances available.
Straightness of laser line
Straightness is an important quality of laser line, which is the deviation of the laser line from an ideal straight line. Calculation: Straightness=L (mm) / D1 (mm).
Depth of field
A sufficient depth of field has to be taken into account when measuring objects of variable height. The depth of field is an important quality of the laser line, which is defined as the working distance range 1.41 times line width. A larger line width laser line will have a far more extended depth of field than a smaller line width laser line.
Uniform intensity （non-Gaussian） distribution or Gaussian distribution
Uniform intensity laser line (non-Gaussian) is usually generated by Powell lenses. Gaussian distribution laser line is usually generated by cylindrical lens. Currently uniform laser line is the trend.
While applied off-axis, relative intensity against position of the laser line varies between uniform distribution and Gaussian distribution. For Gaussian distribution, the position difference will cause change in intensity along the length of the line. For uniform laser line, the position difference has little impact on the intensity along the length of the line.
Off-Axis Angle
For uniform laser line, it’s easy to position the laser line off-axis at a certain angle so that the CCD can collect the image.