Diode laser module 20mW 635 nm bright red, adjustable focus, modulation input - Kopie

Q: What do &bdquo;fixed focus&ldquo; and &bdquo;adjustable&ldquo; mean?

Fixed focus: the optics are set at the factory to a fixed distance and cannot be changed – typically a point in the range 1–5 m. Benefit: no accidental adjustment possible, stable over the entire service life. Trade-off: cannot be adapted to other distances. Adjustable: the optics sit in an adjustable brass ring at the front of the module and can be focused by the user to any desired distance (5 cm to infinity). After adjustment the optics are secured with thread-locking varnish in the thread. Which variant? Fixed focus for defined series production with constant distance, adjustable for flexible applications and one-off setups.

Q: Which typical applications exist for point lasers?

Industrial alignment: point lasers as a reference for aligning machines, conveyors, roller tracks and light barriers. Distance measurement: as a light source in triangulation sensors for distance and profile measurement. Marking: in research and test setups as precise reference points. Optical test setups: as a light source for beam splitting, diffraction and interference experiments. Workpiece positioning: in production as a reference point for drilling and placement operations. Construction: plumb points, height references, wall alignment (not our domain – we supply industrial quality, not DIY plumb lasers).

Q: Why does a green point laser look brighter than a red one?

The human retina is most sensitive in the green spectral range around 555 nm – that is the peak of the eye's spectral sensitivity. Green laser light at 520 nm sits close to this peak, while red light at 650 nm sits at the edge of visual sensitivity. Specifically: a 5 mW green point laser looks visually about as bright as a 25–35 mW red point laser. Practical effect: at equal perceived brightness, green gives you a lower laser class – Class 2 instead of Class 3R for red. This simplifies safety measures significantly. Trade-off: green laser diodes are more expensive and more temperature-sensitive than red ones.

Q: What is beam divergence and why does it matter?

Beam divergence describes how strongly a laser beam expands with distance. It is measured in milliradians (mrad). Example: a beam with 1 mrad divergence widens by 10 cm over 100 m distance. For point lasers low divergence is desirable – so the dot stays sharp over long distances. Typical values: 0.5–2 mrad after collimation. Influencing factors: emitter size of the laser diode, quality of the collimator optics, wavelength. For our OEM modules the divergence is typically specified in each module's datasheet or optimized at the factory.

Q: What do the laser classes 3R and 3B mean?

Class 3R: increased risk on direct viewing of the beam, but the natural blink reflex usually still provides sufficient protection. Safety goggles are recommended but not strictly required in all cases. Maximum 5 mW in the visible range. Class 3B: direct radiation is hazardous to the eye, but diffuse reflections are usually harmless. Safety goggles are mandatory in the open beam area. Beam enclosure where possible, clear marking of laser areas, training of personnel. Maximum 500 mW. Both classes require a laser safety officer in commercial use.

Q: When to choose a point, line or cross laser?

Point lasers (also called dot lasers) project a sharp spot of light – ideal for precise single-point marking, distance measurement, triangulation and alignment tasks over large distances. Benefit: all the optical power is concentrated at the point, giving very high visibility even at low power. Line lasers project a line – ideal for cutting lines, paths and boundaries. Cross lasers project a cross from two lines – ideal for centring and 2D alignment. Rule of thumb: point for „this spot here“, line for „along this axis“, cross for „centred exactly on this intersection“.

Collimator: Glass

LDM-20-635-M: 20 mW bright red (635 nm) dot laser module with adjustable collimator. Compact laser diode module for positioning and alignment.

€139.85

Delivery time: In stock

Collimator

Acrylic

Glass

Product number: LDM-20-635-M.2

Diode laser module 20mW 635 nm bright red, adjustable focus, modulation input - Kopie

Spot Laser Module 20 mW Bright Red (635 nm) – LDM-20-635-M: Compact, high-performance laser diode module that projects a sharp laser spot—with an adjustable collimator (focus range approx. 5 cm to infinity). Suitable for highly visible positioning and alignment marks, as well as for integration into devices and machines. The laser can be pulsed or switched via the TTL modulation input (0–5 V).

Bright red laser spot (635 nm) with 20 mW
Adjustable collimator, focus range approx. 5 cm to infinity
TTL-modulable (0–5 V) for clocking and switching

Technical Specifications

Laser power:	20 mW
Wavelength / Color:	635 nm BRIGHT RED
Focus range:	approx. 5 cm to infinity
Divergence:	typ. < 0.7 mrad
Power supply:	3–5 VDC / < 100 mA
Potential:	PLUS on the housing
Modulation	0–5 V TTL, up to approx. 10 kHz
Length of connection wires:	Stranded wires, approx. 200 mm
Dimensions:	12 x 40 mm
Temperature range:	-15°C to +45°C
Service life:	typ. > 25,000 h

Notes

Observe the laser class!
For more information on laser safety, click here.

Collimator:	Acrylic, Glass

What do „fixed focus“ and „adjustable“ mean?

Fixed focus: the optics are set at the factory to a fixed distance and cannot be changed – typically a point in the range 1–5 m. Benefit: no accidental adjustment possible, stable over the entire service life. Trade-off: cannot be adapted to other distances. Adjustable: the optics sit in an adjustable brass ring at the front of the module and can be focused by the user to any desired distance (5 cm to infinity). After adjustment the optics are secured with thread-locking varnish in the thread. Which variant? Fixed focus for defined series production with constant distance, adjustable for flexible applications and one-off setups.

Which typical applications exist for point lasers?

Industrial alignment: point lasers as a reference for aligning machines, conveyors, roller tracks and light barriers. Distance measurement: as a light source in triangulation sensors for distance and profile measurement. Marking: in research and test setups as precise reference points. Optical test setups: as a light source for beam splitting, diffraction and interference experiments. Workpiece positioning: in production as a reference point for drilling and placement operations. Construction: plumb points, height references, wall alignment (not our domain – we supply industrial quality, not DIY plumb lasers).

Why does a green point laser look brighter than a red one?

The human retina is most sensitive in the green spectral range around 555 nm – that is the peak of the eye's spectral sensitivity. Green laser light at 520 nm sits close to this peak, while red light at 650 nm sits at the edge of visual sensitivity. Specifically: a 5 mW green point laser looks visually about as bright as a 25–35 mW red point laser. Practical effect: at equal perceived brightness, green gives you a lower laser class – Class 2 instead of Class 3R for red. This simplifies safety measures significantly. Trade-off: green laser diodes are more expensive and more temperature-sensitive than red ones.

What is beam divergence and why does it matter?

Beam divergence describes how strongly a laser beam expands with distance. It is measured in milliradians (mrad). Example: a beam with 1 mrad divergence widens by 10 cm over 100 m distance. For point lasers low divergence is desirable – so the dot stays sharp over long distances. Typical values: 0.5–2 mrad after collimation. Influencing factors: emitter size of the laser diode, quality of the collimator optics, wavelength. For our OEM modules the divergence is typically specified in each module's datasheet or optimized at the factory.

What do the laser classes 3R and 3B mean?

Class 3R: increased risk on direct viewing of the beam, but the natural blink reflex usually still provides sufficient protection. Safety goggles are recommended but not strictly required in all cases. Maximum 5 mW in the visible range. Class 3B: direct radiation is hazardous to the eye, but diffuse reflections are usually harmless. Safety goggles are mandatory in the open beam area. Beam enclosure where possible, clear marking of laser areas, training of personnel. Maximum 500 mW. Both classes require a laser safety officer in commercial use.

When to choose a point, line or cross laser?

Point lasers (also called dot lasers) project a sharp spot of light – ideal for precise single-point marking, distance measurement, triangulation and alignment tasks over large distances. Benefit: all the optical power is concentrated at the point, giving very high visibility even at low power. Line lasers project a line – ideal for cutting lines, paths and boundaries. Cross lasers project a cross from two lines – ideal for centring and 2D alignment. Rule of thumb: point for „this spot here“, line for „along this axis“, cross for „centred exactly on this intersection“.