InLine Cross Line Laser, 20 mW, Bright Red, 635 nm

Q: What is the difference between light red (635 nm) and red (650 nm)?

Both wavelengths appear red to the eye, but light red (635 nm) sits closer to the peak sensitivity of the human retina than red (650 nm). Specifically: 635 nm light appears roughly 2× brighter than 650 nm light at the same optical power. Practical effect: a 20 mW light-red module looks visually comparable to a 40 mW red module – with a lower laser class and longer diode service life. Light-red modules are slightly more expensive to manufacture but pay off in brighter environments or where a lower laser class is required.

Q: Glass optics vs. acrylic optics – when which?

Acrylic optics (PMMA plastic): low cost, light, dimensionally stable. Optically very good in standard applications, but temperature-sensitive – the refractive index changes with temperature, shifting the focus when variation exceeds ±5 °C. Perfectly adequate for indoor applications with stable conditions. Glass optics: heavier, more expensive, but temperature-stable. The refractive index stays nearly constant across wide temperature swings. Ideal for: outdoor mounting, unheated halls, machines with large temperature swings (welding, sawmills in summer/winter) and applications needing high repeat accuracy over long periods. Glass optics are available as an optional upgrade on our KLM and LLM modules.

Q: What does &bdquo;stabilized and peak-free power supply&ldquo; mean (cross-line laser)?

Cross-line laser modules contain sensitive laser diodes that can be destroyed within microseconds by voltage spikes and current fluctuations. Stabilized means: constant output voltage under load, no sag during switch-on. Peak-free means: no switching spikes or overshoot on the supply line. Always use a switching power supply with sufficient smoothing or a dedicated laser diode driver. Avoid unfiltered supplies, cheap USB power banks without stabilization, and supplies shared with switching relays or motors. The DC variant of our modules includes integrated reverse-polarity protection.

Q: When is the optional glass collimator worthwhile?

The standard version of our KLM modules ships with an aspheric acrylic lens – sufficient for stable indoor temperatures. With strongly fluctuating operating temperatures (more than ±5 °C variation) the acrylic lens can shift focus – beam width changes and sharpness suffers. The optional three-lens glass collimator is significantly more temperature-stable: glass barely expands, so the focus stays constant. Recommended for: outdoor mounting, unheated halls, machines with large temperature swings (welding, sawmills in summer/winter) and applications needing high repeat accuracy over long periods.

Q: How big is the cross at a given distance?

The cross size scales linearly with distance. With a 90° lens angle on a 12 mm module, 1 m distance gives a cross with roughly 2 m line length per axis. At 2 m distance this doubles to about 4 m per axis. With narrower angles (e.g. 35°) the cross is correspondingly smaller: 0.62 m at 1 m distance. Note: as distance grows the cross gets not only larger but also wider in line width (beam divergence). For especially sharp crosses at a known distance, the focus is adjusted on the module (brass ring at the front).

Q: Which colour for which surface (cross-line laser)?

Red (650 nm): standard choice, lowest cost, sufficient in moderately lit environments. Light red (635 nm): noticeably brighter than 650 nm red at the same power, good visibility on most surfaces. Green (520 nm): appears roughly 5–7× brighter than red – the choice for very bright environments, visible in daylight, large distances or dark surfaces. Blue (450 nm): ideal on wood, vegetation, greenish or yellow surfaces – where red and green get lost in the background. Light blue (488 nm): high contrast on warm-light spectra, a special colour for surfaces such as red-toned woods.

Q: Cross-line laser vs. line laser vs. positioning laser – what are the differences?

Line laser: projects one line – ideal for cutting lines, paths and boundaries. Cross-line laser: projects two perpendicular lines as a cross (90°) – ideal for centring and aligning. Positioning laser with DOE optics: projects a pattern (crosshair, circle, search field, square) through a diffractive optical element – the image has constant brightness across the entire area, but the lines are inherently wider than with classic lens optics. In short: line for straight markings, cross-line laser for precise centring with sharp lines, DOE positioning laser for evenly bright patterns including the outer areas.

Q: What is a cross-line laser?

A cross-line laser (also called cross hair laser) projects two perpendicular lines (90°) – a true line cross – onto a surface. Unlike a positioning laser with DOE optics, the cross here is generated by two classic cylindrical lenses. Benefits: sharp, bright lines across the full image width, daylight-capable – good visibility even in daylight and bright environments. Typical applications are workpiece centring on CNC, sawing and drilling machines, microscope reference crosses, inspection stations and operator guidance at manual workstations. Cross-line laser modules are available in red, light red (635 nm), green, blue and light blue – each with adjustable focus.

Cross line laser InLine BRIGHT RED 20mW

InLine Series Bright Red 20 mW (635 nm) cross line laser – IL-20-635-C: High-performance cross line laser from the industrial InLine series in a rugged housing with internal control electronics that projects a bright red laser cross. Wide voltage input and optional trigger input for flexible use in machines and systems.

Bright red laser cross (635 nm) with approx. 20 mW
Industrial InLine design with internal control electronics
Wide voltage input, 230 VAC via optional power supply
Optional trigger input (PLC-compatible)

The laser diodes are equipped with ACC control for high stability, as well as a startup ramp that slowly increases the current at power-on and protects the diode from inrush spikes.

Technical Specifications

Laser power:	approx. 20 mW
Wavelength:	635 nm BRIGHT RED
beam angle:	selectable
laser class:	1/2, depending on installation
Power supply:	approx. 9–25 VDC, 230 VAC via optional power supply
Trigger input:	4–25 V = On, 0 V = Off
Module connection:	1 m flexible cable, optional hollow connector
IP rating:	IP 65 / 68 (optional)
Dimensions:	approx. 18 x 100 mm
Service life:	typically > 25,000 hours when mounted on a metal mount
Temperature range:	approx. -20° C to +45° C

Cross size and line width

The size of the projected cross is determined by the selected beam angle and the mounting distance:

Angle	Distance	Line length approx.
5°	1 m	approx. 8 cm
15°	1 m	0.25 m
45°	1 m	85 cm
55°	1 m	1 m
75°	1 m	170 cm
100°	1 m	230 cm

Trigger Input

The InLine line lasers can be equipped with an optional trigger input for modulating or power-free on/off switching of the laser output. The voltage-controlled input turns on the laser at a signal voltage of approximately 4 V. The input voltage may be up to 25 V and can therefore also come from a PLC output. This allows for a convenient control solution without having to disconnect the supply voltage. If the laser is to operate continuously, simply connect the trigger input to the supply voltage.

Notes

Observe the laser class!
Further information on laser safety can be found here.

Connection type:	Flex cable 1m, M8 connector, M12 connector, Power supply with DC connector, Trigger input
Cross angle:	15 deg, 55 deg, 75 deg, 90 deg
IP Rating:	IP 65, IP67/68
Mount:	No mount, Pan/Tilt magnetic mount, Strong Pan/Tilt, Tilt Mount

What is the difference between light red (635 nm) and red (650 nm)?

Both wavelengths appear red to the eye, but light red (635 nm) sits closer to the peak sensitivity of the human retina than red (650 nm). Specifically: 635 nm light appears roughly 2× brighter than 650 nm light at the same optical power. Practical effect: a 20 mW light-red module looks visually comparable to a 40 mW red module – with a lower laser class and longer diode service life. Light-red modules are slightly more expensive to manufacture but pay off in brighter environments or where a lower laser class is required.

Glass optics vs. acrylic optics – when which?

Acrylic optics (PMMA plastic): low cost, light, dimensionally stable. Optically very good in standard applications, but temperature-sensitive – the refractive index changes with temperature, shifting the focus when variation exceeds ±5 °C. Perfectly adequate for indoor applications with stable conditions. Glass optics: heavier, more expensive, but temperature-stable. The refractive index stays nearly constant across wide temperature swings. Ideal for: outdoor mounting, unheated halls, machines with large temperature swings (welding, sawmills in summer/winter) and applications needing high repeat accuracy over long periods. Glass optics are available as an optional upgrade on our KLM and LLM modules.

What does „stabilized and peak-free power supply“ mean (cross-line laser)?

Cross-line laser modules contain sensitive laser diodes that can be destroyed within microseconds by voltage spikes and current fluctuations. Stabilized means: constant output voltage under load, no sag during switch-on. Peak-free means: no switching spikes or overshoot on the supply line. Always use a switching power supply with sufficient smoothing or a dedicated laser diode driver. Avoid unfiltered supplies, cheap USB power banks without stabilization, and supplies shared with switching relays or motors. The DC variant of our modules includes integrated reverse-polarity protection.

When is the optional glass collimator worthwhile?

The standard version of our KLM modules ships with an aspheric acrylic lens – sufficient for stable indoor temperatures. With strongly fluctuating operating temperatures (more than ±5 °C variation) the acrylic lens can shift focus – beam width changes and sharpness suffers. The optional three-lens glass collimator is significantly more temperature-stable: glass barely expands, so the focus stays constant. Recommended for: outdoor mounting, unheated halls, machines with large temperature swings (welding, sawmills in summer/winter) and applications needing high repeat accuracy over long periods.

How big is the cross at a given distance?

The cross size scales linearly with distance. With a 90° lens angle on a 12 mm module, 1 m distance gives a cross with roughly 2 m line length per axis. At 2 m distance this doubles to about 4 m per axis. With narrower angles (e.g. 35°) the cross is correspondingly smaller: 0.62 m at 1 m distance. Note: as distance grows the cross gets not only larger but also wider in line width (beam divergence). For especially sharp crosses at a known distance, the focus is adjusted on the module (brass ring at the front).

Which colour for which surface (cross-line laser)?

Red (650 nm): standard choice, lowest cost, sufficient in moderately lit environments. Light red (635 nm): noticeably brighter than 650 nm red at the same power, good visibility on most surfaces. Green (520 nm): appears roughly 5–7× brighter than red – the choice for very bright environments, visible in daylight, large distances or dark surfaces. Blue (450 nm): ideal on wood, vegetation, greenish or yellow surfaces – where red and green get lost in the background. Light blue (488 nm): high contrast on warm-light spectra, a special colour for surfaces such as red-toned woods.

Cross-line laser vs. line laser vs. positioning laser – what are the differences?

Line laser: projects one line – ideal for cutting lines, paths and boundaries. Cross-line laser: projects two perpendicular lines as a cross (90°) – ideal for centring and aligning. Positioning laser with DOE optics: projects a pattern (crosshair, circle, search field, square) through a diffractive optical element – the image has constant brightness across the entire area, but the lines are inherently wider than with classic lens optics. In short: line for straight markings, cross-line laser for precise centring with sharp lines, DOE positioning laser for evenly bright patterns including the outer areas.

What is a cross-line laser?

A cross-line laser (also called cross hair laser) projects two perpendicular lines (90°) – a true line cross – onto a surface. Unlike a positioning laser with DOE optics, the cross here is generated by two classic cylindrical lenses. Benefits: sharp, bright lines across the full image width, daylight-capable – good visibility even in daylight and bright environments. Typical applications are workpiece centring on CNC, sawing and drilling machines, microscope reference crosses, inspection stations and operator guidance at manual workstations. Cross-line laser modules are available in red, light red (635 nm), green, blue and light blue – each with adjustable focus.