Positioning Laser Module, 25 mW, Green Cross Hairs

Q: What is pick-by-light used for?

Pick-by-light is an optical guidance system used in logistics and assembly: a laser shows the worker the next position to pick or the location of the next work step. Instead of reading lists or checking screens, the worker simply follows the laser. Benefits: fewer pick errors, faster cycle times, shorter training, low noise. Used in: order-picking warehouses (picking from shelf compartments), manual assembly (which screw next), placement (which position on the workpiece), packing (which box gets the item). Our DOE positioning lasers are well suited because they project clearly visible, defined patterns.

Q: How large is the pattern at a given distance?

The image size scales linearly with distance. With a PLM module at approx. 30° opening angle, 1 m distance gives an image of around 30 cm diagonal. At 2 m this doubles to 60 cm; at 0.5 m it halves to 15 cm. Recommended operating distance: 5 cm to approx. 100 cm. Beyond 100 cm the line sharpness drops noticeably, because DOE optics widen the line proportionally with distance. For very large distances we recommend the FloorPoint (100 mW at 532 nm) or an ILP laser projector.

Q: Which DOE patterns are available?

We offer five standard patterns: Laser crosshair „CH“ – classic +-cross for centring. Circle „Circle“ – marking circular areas (e.g. drill positions). Search field „SF“ – a larger highlighted area for visual orientation. Square „SQ“ – rectangular marking for pallet positions or boxes. Dot grid – on request for special patterns such as pick grids. The standard patterns are encoded in the product codes (e.g. PLM-30-650-CH = crosshair, PLM-10-650-SQ = square). Custom DOEs with company-specific logos or special alignment marks are available on request.

Q: What do the laser classes 1M and 2M mean?

Classes 1M and 2M according to EN 60825-1 stand for „Magnifying Optics“ – lasers that are safe under normal conditions but whose radiation can become hazardous when viewed through optical aids such as magnifiers, binoculars or microscopes. With DOE positioning lasers the optical power is spread across the pattern – but if a lens were to refocus the radiation, the power density could reach hazardous levels. Practical consequence: safe for normal industrial use without safety goggles. Prohibited: viewing the beam through magnifiers, binoculars or microscopes.

Q: DOE optics vs. classic lens optics – pros and cons?

Classic lens optics (cross-line laser): very sharp, narrow lines; brightest at the centre, fading towards the line ends (Gaussian profile). Ideal for precise centring where line sharpness is critical. DOE optics (positioning laser): even brightness across the entire pattern, defined outer boundary, arbitrary patterns possible. Lines are inherently a little wider and less sharp than with lens optics. When to choose which? Classic optics for micrometre-level centring and microscope work. DOE optics for operator guidance, pick-by-light and anywhere the whole pattern must be evenly visible.

Q: What is a DOE (diffractive optical element) and how does it work?

A DOE – diffractive optical element – is a special optic that generates a pattern through diffraction rather than through classic refraction at lenses. Instead of just a single line or dot, arbitrary patterns are formed: crosshairs, circles, squares, search fields, dot grids or marking symbols. The advantage over classic lens optics: constant brightness across the entire pattern area – even the outer edges of a crosshair are as bright as the centre. The trade-off: lines are inherently a little wider than with classic lens optics. DOE modules are ideal for operator guidance, pick-by-light and position indication.

Positioning laser module 25 mW GREEN "cross hair", insulated, adjustable focus

25 mW Green "Cross Hair" Positioning Laser Module (520 nm) – PLM-25-520-CH: Compact laser diode module with DOE digital optics that projects a green cross hair onto the work surface—for positioning, alignment, and operator guidance tasks. The focus is adjustable.

"Cross hair" projection pattern via DOE digital optics
Green pattern (520 nm) with 25 mW
Image size approx. 30 cm at 1 m
Compact 12-mm module for integration into devices and machines

Technical Specifications

Laser power	25 mW
Wavelength/Color	520 nm GREEN
Image Size	approx. 30 cm at 1 m
Focus range	Approx. 5 cm to approx. 150 cm, recommended up to max. 100 cm
Power supply	3–6 VDC / < 250 mA, optional 24 VDC or 230 VAC
Length of connection cables	Stranded wires approx. 100 mm, hollow connectors approx. 200 mm
Laser class after setup	Class 1 or 1M/2, depending on the installation type
Dimensions	12 x 37 mm
Temperature range	- 10°C to +40°C
Service life	typ. > 25,000 h

Notes

Observe the laser class!
For more information on laser safety, click here.
For continuous operation, the module must be mounted in a heat sink.
Stabilized, peak-free power supply!

Options

Hollow-pin connector; direct operation via plug-in power supply is possible.
Various power supply types
Glass collimator, for stable operation under higher temperature fluctuations
Fully adjustable mounts

Collimator:	Acrylic, Glass
Connection type:	12-25VDC, 12-25VDC with M8 connector, 12-25VDC with M12 connector, 110-230VAC, Barrel connector, Wires
Mount:	Ball mount 3D with wall mount, Magnet ball head, No mount, Strong Pan/Tilt

What is pick-by-light used for?

Pick-by-light is an optical guidance system used in logistics and assembly: a laser shows the worker the next position to pick or the location of the next work step. Instead of reading lists or checking screens, the worker simply follows the laser. Benefits: fewer pick errors, faster cycle times, shorter training, low noise. Used in: order-picking warehouses (picking from shelf compartments), manual assembly (which screw next), placement (which position on the workpiece), packing (which box gets the item). Our DOE positioning lasers are well suited because they project clearly visible, defined patterns.

How large is the pattern at a given distance?

The image size scales linearly with distance. With a PLM module at approx. 30° opening angle, 1 m distance gives an image of around 30 cm diagonal. At 2 m this doubles to 60 cm; at 0.5 m it halves to 15 cm. Recommended operating distance: 5 cm to approx. 100 cm. Beyond 100 cm the line sharpness drops noticeably, because DOE optics widen the line proportionally with distance. For very large distances we recommend the FloorPoint (100 mW at 532 nm) or an ILP laser projector.

Which DOE patterns are available?

We offer five standard patterns: Laser crosshair „CH“ – classic +-cross for centring. Circle „Circle“ – marking circular areas (e.g. drill positions). Search field „SF“ – a larger highlighted area for visual orientation. Square „SQ“ – rectangular marking for pallet positions or boxes. Dot grid – on request for special patterns such as pick grids. The standard patterns are encoded in the product codes (e.g. PLM-30-650-CH = crosshair, PLM-10-650-SQ = square). Custom DOEs with company-specific logos or special alignment marks are available on request.

What do the laser classes 1M and 2M mean?

Classes 1M and 2M according to EN 60825-1 stand for „Magnifying Optics“ – lasers that are safe under normal conditions but whose radiation can become hazardous when viewed through optical aids such as magnifiers, binoculars or microscopes. With DOE positioning lasers the optical power is spread across the pattern – but if a lens were to refocus the radiation, the power density could reach hazardous levels. Practical consequence: safe for normal industrial use without safety goggles. Prohibited: viewing the beam through magnifiers, binoculars or microscopes.

DOE optics vs. classic lens optics – pros and cons?

Classic lens optics (cross-line laser): very sharp, narrow lines; brightest at the centre, fading towards the line ends (Gaussian profile). Ideal for precise centring where line sharpness is critical. DOE optics (positioning laser): even brightness across the entire pattern, defined outer boundary, arbitrary patterns possible. Lines are inherently a little wider and less sharp than with lens optics. When to choose which? Classic optics for micrometre-level centring and microscope work. DOE optics for operator guidance, pick-by-light and anywhere the whole pattern must be evenly visible.

What is a DOE (diffractive optical element) and how does it work?

A DOE – diffractive optical element – is a special optic that generates a pattern through diffraction rather than through classic refraction at lenses. Instead of just a single line or dot, arbitrary patterns are formed: crosshairs, circles, squares, search fields, dot grids or marking symbols. The advantage over classic lens optics: constant brightness across the entire pattern area – even the outer edges of a crosshair are as bright as the centre. The trade-off: lines are inherently a little wider than with classic lens optics. DOE modules are ideal for operator guidance, pick-by-light and position indication.