Laser Line Module Selection: Angle, Wavelength, Current

In a laser level, the module is the optical engine. The line the user sees on the wall starts at a diode a few millimetres wide and a cylindrical lens, and two numbers decide whether that line is still usable at six metres: the fan angle and the wavelength. Bosch's published data sheet for the GLL 3-80 line laser lists a 630–650 nm diode below 10 mW, laser class 2, working range up to 30 m. That is the class of tool the module has to live inside.

Our 0300X range covers the projection slot. The current catalogue lists 28 models: 03000 through 03033, plus DS008, LDG01 to LDG04, and LDR03. Everything below is how we would choose between them, and where the catalogue stops answering for you.

Direct answer: three parameters fix the selection — wavelength (520, 635 or 650 nm), fan angle (30°, 45°, 60°, 90°, 110° or 120°), and the supply you can give it (DC 3–12 V, drawing 30 mA at 650 nm and 50 mA at 635 nm). The pattern — single line, cross line, dot or ground line — is the fourth choice, and it is the one buyers usually make first. We would make it last.

What the range actually covers, as published

The parameter block we publish is identical across all 28 models:

Read that table the way an engineer reads a family datasheet. The electrical envelope is fixed; what changes between models is the projection configuration you order and the mechanics around it. If a project needs something outside those six angles or those three wavelengths, the honest answer is that you are outside this family, not that a special is one email away.

Fan angle is geometry, and geometry costs light

The line length at a given distance is L = 2d × tan(θ/2), where d is the distance to the surface and θ the fan angle. At three metres:

A 120° module covers about 6.5 times the line length of a 30° module at the same distance. If the diode output is held constant, that energy is spread over that much more surface, so the line reads dimmer per centimetre. This is the trade buyers miss most often: they order the widest angle for coverage, then complain the line is faint on a bright site. Wide angle and bright line are the same budget spent two ways.

Pick the narrowest angle that still spans your work area, and move the tool closer if it does not.

520, 635, 650: what the wavelength really changes

• 650 nm is the deep red most red-line tools use. It is the cheapest build in the range and it draws 30 mA.
• 635 nm is the red-orange build. It sits closer to the eye's peak than 650 nm, so it reads brighter on the same optical power. The published current for that build is 50 mA, roughly 1.7 times the 650 nm figure, which is battery life you will notice on a cordless tool.
• 520 nm green sits close to the 555 nm peak of photopic eye response. That is why green lines hold up in daylight and why green tools cost more: the perceived gain is real, the component cost is real too.

One gap in our own documentation, stated plainly: the catalogue does not quote a current figure for the 520 nm build. We have not invented one for this article. Size the driver from measured samples, not from a datasheet row that does not exist.

The supply is part of the optical design

DC 3–12 V describes the input window, not a licence to hang the module on any 3–12 V rail. Laser diodes are current-driven devices. A rail with no current limit will push the diode past its rating on the first cold start, and the diode degrades quietly instead of failing at the bench. You find out six months later, from a customer.

Where a project needs a dedicated supply, our B-series laser DC supplies are the matching part. B26 is published as TÜV/CE/UL, with dual input versions (AC 230–240 V 50 Hz for Europe and Asia, AC 120 V 60 Hz for North America), output DC 3 ± 0.3 V at 50 mA maximum.

Do the arithmetic before you commit. A 50 mA maximum against a 635 nm module that draws 50 mA leaves no margin at all. For that build, either run the 650 nm version or ask for a supply with headroom. We would rather tell you this now than handle the return later.

Compliance: what the certificate covers, and what it does not

Every model in the series is published as TÜV/CE · EMC · FDA compliant, and the modules are built in our TÜV-accredited facility. Certificate documents are shared during technical review; the Certificate Library is the entry point.

Here is the boundary. A module is a component. The class label on a finished tool belongs to the complete optical assembly, and it is assigned against EN 60825-1 / IEC 60825-1 in Europe and 21 CFR 1040.10 and 1040.11 in the United States. We can hand you the module's compliance and EMC evidence. We cannot hand you a class 2 label for a product we did not build, and any supplier who offers one is selling you paperwork that will not survive a customs or notified-body review.

Two things this family is not

It is not a ranging module. Distance meters such as the Leica DISTO or Bosch GLM use a 650 nm class 2 source for time-of-flight measurement. ToF ranging modules and line-projection modules are different component classes, and swapping one for the other breaks the optical scheme rather than saving a line on the BOM.

It is not a drop-in for a level design either, in the sense that a connector swap would be. Collimation, mount flatness and the driver all sit around the module, and a module that tests well on a bench can still print a curved line once it is bolted to a die-cast housing. Sample under your own ambient light, on your own housing, before you release a tooling order.

A short pre-order checklist

• Fix the fan angle from the working distance you must cover, not from the widest option available.
• Write down the wavelength and the published current for that build, then check it against your battery budget.
• Confirm the supply is current-limited, and that its maximum is above your module's draw.
• Decide who owns the laser class label, and get that in writing before the first shipment.
• For 520 nm, ask for measured current before you finalise the driver.

Full model list and per-model pages are on the 28-model series page; the wider range sits under Laser Modules, with dedicated supplies on the Laser DC Power Supplies page. If you are matching a module to an existing level design, send the housing drawing and the supply rail; samples and datasheets follow from that.

FAQ

What fan angle do I need for a 5 m working distance?

Line length at 5 m is 2.7 m at 30°, 5.8 m at 60° and 17.3 m at 120°. Choose the narrowest angle that spans the area you must cover, because a wider fan spreads the same optical energy over a longer line and reads dimmer.

520 nm or 650 nm for an indoor level?

650 nm at 30 mA is the cheapest build and the usual choice for indoor work under controlled light. 520 nm green sits near the peak of eye sensitivity, so it stays visible in daylight, at a higher component cost. The catalogue does not publish a current figure for the 520 nm build, so size that driver from samples.

Do the modules include a driver?

No. The modules take DC 3–12 V, and a bare rail without current limiting is not a driver. Where a dedicated supply is needed, the B-series laser DC supplies are the matching part, for example B26 at DC 3 ± 0.3 V, 50 mA maximum, TÜV/CE/UL.

Does the module's FDA compliance make my tool class 2?

No. Compliance evidence travels with the component; the class label belongs to the finished optical assembly and is assigned against EN 60825-1 / IEC 60825-1 or 21 CFR 1040.10 and 1040.11 by whoever builds the tool.

Can I use a line module for distance measurement?

No. Ranging needs a time-of-flight module, the class of component used in distance meters. A line-projection module produces a visible reference line and will not range.

Need a certified laser projection module for your level, positioner or measurement device? Contact DKLD — samples and datasheets within 24 hours. Explore the full laser module range and certificate library.