Moritex Machine Vision Lighting Alternatives: Six Parameters That Decide Contrast

Lighting substitution fails in a particular way. The new source is the same shape, the same colour and roughly the same size, the image looks bright enough, and the pass rate changes anyway — usually downward, usually on one feature. A machine vision light is not specified by shape and colour, but by how its spectrum meets the material, how even the field is across the area being read, how it is driven, and where it can physically sit.

In the POMEAS global company intelligence set of 2,602 companies, 5 have publicly documented Moritex lighting in use on their own equipment: enough to make the substitution question real, not enough to justify a product-for-product comparison. So this article sets out the six parameters that decide whether a replacement produces the same contrast.

The six parameters to verify before substituting a light

1. Wavelength and colour temperature against the material's response

Colour is the first thing people match and the last thing they should fix. The question is not "was it red" but "why red": a wavelength is chosen because it produces contrast between a feature and its background on a specific material.

POMEAS publishes the spectral figures. Red is 625 nm on GHN, GBT, GC, GR and GP0801 / GP0803, approximately 625 nm on GH and GL. Blue is 470 nm. White is a colour temperature of 6500 K. Beyond those: green 525 nm, near-infrared 850–950 nm and ultraviolet 365–395 nm on GC and GL; 365 nm or 395 nm on the UV series; 850 nm or 940 nm on the IR series.

Two published rules carry into any substitution. On VP-GLTD, red gives a stable black-and-white silhouette, green has good camera response in some dimensional systems, blue suits fine-edge work, white is the choice where a broad spectrum is needed. On the UV series, test 365 nm and 395 nm on a real sample.

2. Uniformity, and the conditions it is measured under

Uniformity is most often requested as a percentage and least often published as one. No POMEAS lighting page quotes a uniformity percentage, so the honest answer is that it is not published. What is published is the mechanism: a diffuser plate and light-guide structure on GBT, a diffuser on GHN, a spherical integrating surface on GR, and 1 to 7 LED rings on GH.

Verify it on your own field: put a flat white target at the working distance, hold exposure constant, and read grey values across the area you measure, corners included. Check for the LED pitch showing through as ripple.

3. Power supply, controller, brightness control and strobe

Almost the whole range runs on 24 V DC: GH, GHN, GBT, GL and GC, and the ring, bar, area and coaxial forms of the UV and IR series. Point sources are the exception — GP0801 and GP0803 on 5 V, the UV point source on 5 V, and in the IR series most models at 24 V with GP0803-IR-3P at 5 V. VP-GLTD and VP-GLTDL publish the LED drive: 3.5 V forward, 350 mA.

Brightness is controlled at the controller, not the lamp. GBT, GH and GHN work with a machine vision light source controller so brightness follows camera exposure time, inspection speed and site environment; the recommended model on GBT and GH is VP-DPI2404-4-RS232T. The controller category covers LED brightness and strobe control, but no strobe frequency, pulse width or trigger timing is published. Published power ranges: 0.8–29 W on GBT, about 0.4–41.8 W on GH, 0.8–120 W on GC, about 0.8–6 W on IR, 1.7–6.2 W on UV.

4. Geometry, and the entry area it gives you

Geometry decides which surfaces are lit. Ring — GH at about 25–350 mm outer diameter, GHN at 80, 116, 132, 166 and 196 mm. Dome — GR in GR70, GR116, GR175, GR198, GR260 and GR325. Coaxial — GC, using a high-density LED array and a semi-transparent beamsplitter so illumination and imaging share one axis. Bar — GL in GL-14 and GL-34 at 50, 100, 150, 200, 250 and 300 mm. Flat area / backlight — GBT, whose emitting-area figures are not published. Parallel backlight — VP-GLTD at 30 to 265 mm beam diameters, VP-GLTDL in a right-angle body. Point — GP0801 and GP0803, 8 mm front end, 6 mm emitting area.

Published selection rule: ring around the lens, bar for a direction, area light as a backlight, coaxial for flat or reflective surfaces, dome for glossy curved surfaces, point where nothing else fits.

5. Working distance, and whether the beam covers the field

This most often breaks a measurement: a source that is bright but too small gives a field bright in the middle and falling off where the features are. VP-GLTD publishes both halves. Working distance across the range is 45–500 mm, allocated per beam diameter: 30 mm at 45–90 mm, 60 mm at 90–180 mm, 100 mm at 150–300 mm, 145 mm at 100–300 mm, 189 mm at 250–500 mm, 265 mm at 150–500 mm. The beam diameter must exceed the actual inspection field, with margin beyond the part edge — for about 90 mm, choose 100 mm or larger. For other series, working distance is not published as a number.

6. Thermal path, duty and lifetime

LED output drifts with junction temperature, and a light that warms over a shift moves the grey levels the algorithm was taught on. Structurally, GBT, GH, GHN and GC use an aluminium housing with a PCB substrate and thermally conductive silicone so heat is conducted into the metal shell.

On lifetime the figures come with their conditions: at 25 °C with a white source at 50 % brightness continuously, expected reliable operating time exceeds 30,000 hours, published for GBT, GHN, GH, GL, GC, GR and GP0801 / GP0803. Actual life is affected by brightness setting, temperature, heat dissipation and environment. Operating environment is published for some series: 0–40 °C, with 20 %–85 % RH non-condensing where stated.

Where POMEAS lights land on those six

How to read this table

The six rows describe six geometries doing six jobs; none of the figures is a ranking. A 0.8–120 W range on GC is not "more powerful" than 0.8–29 W on GBT: the coaxial path loses light at the beamsplitter. Working distance is published only for the parallel backlights, and uniformity is not published as a percentage anywhere.

What those numbers mean on the line

Scenario 1 — Silhouette edge for dimensional measurement

VP-GLTD is built for this. Its collimated output reduces the edge blur that diffuse backlight produces when light wraps around a boundary, which is what moves a measured edge by a few micrometres. Specify beam diameter first — larger than the field, with margin; for about 90 mm the recommendation is 100 mm or larger — then working distance against your mounting space.

Scenario 2 — Glossy, curved or uneven surfaces

GR and GHN are the two answers, and they are not interchangeable. GR is a dome: light reflects and diffuses off the spherical interior before reaching the part, arriving from many directions, which removes the dark zones side lighting leaves on curved or stepped surfaces. GHN is a shadowless ring for when the dome will not fit: 80, 116, 132, 166 and 196 mm outer diameters.

Scenario 3 — Specular flat surfaces: scratches, characters, codes

GC is the geometry, because illumination and imaging share one axis. Light from a high-density LED array is reflected by a semi-transparent beamsplitter onto the part and returns through the same plate to the camera, suppressing the uneven reflection off-axis lighting produces on mirror-finish metal, glass and wafers. Its colour range is the widest in the catalogue — 625 nm, 6500 K and 470 nm as standard, with 525 nm, 850–950 nm and 365–395 nm available.

Scenario 4 — Fluorescence, penetration, and no room to mount anything

When a feature only appears at one wavelength, geometry is secondary. The UV series supplies 365 nm or 395 nm in ring, bar, area, coaxial and point forms at 1.7–6.2 W for UV adhesive, fluorescent marks, anti-counterfeit codes and ITO circuits. The IR series supplies 850 nm or 940 nm at about 0.8–6 W in the same five forms for penetration work and die-bonder positioning. Where space is the constraint, GP0801 and GP0803 fit: 6 mm emitting area behind an 8 mm front end, 5 V, 1 W or 3 W.

Writing the replacement specification when the original is discontinued

A specification written as "equivalent to the existing ring light, red, 100 mm" will be quoted against and will fail. Write the measurement requirement instead: the contrast you need, as a feature and a background; wavelength with the reason; uniformity as a test method rather than a number; drive — voltage, channel count, brightness range, whether strobe is required, and strobe timing, which is not published; geometry and entry area against the mounting space; and environment and duty, since the figure of more than 30,000 hours is quoted at 25 °C and 50 % white. Then insist on a lighting test on your own parts.

What this comparison does not tell you

This is a parameter reference, not a compatibility statement. No claim is made that any POMEAS light is a drop-in replacement for a specific third-party illuminator, and none should be inferred. Whether a substitute produces the contrast your recipe needs can only be settled by a lighting test.

Third-party brand names appear only as recorded in customer-supplied intelligence: companies describing their own installed equipment in public material. No third-party specification is quoted, because none was verified. The count of 5 is evidence about installed base.

Brightness is not contrast: a source can be brighter than the original and still fail, because contrast is the difference between feature and background. Uniformity matters for the same reason — an uneven field shifts the local grey values the threshold was set against.

FAQ

Is matching the colour enough when replacing a light?

No. Colour is chosen because it produces contrast on a specific material. POMEAS publishes 625 nm red, 470 nm blue and 6500 K white, with 525 nm, 850–950 nm and 365–395 nm optional.

Does POMEAS publish a uniformity percentage?

No. What is published is the mechanism — diffuser and light guide on GBT and GHN, a spherical integrating surface on GR, 1 to 7 LED rings on GH.

What voltage do the lights run on?

24 V DC for GH, GHN, GBT, GL and GC and for the non-point forms of the UV and IR series; 5 V for GP0801, GP0803 and the UV and IR point sources.

Which beam diameter do I need for a backlight?

Larger than the inspection field, with margin beyond the part edge. VP-GLTD is published at 30, 60, 100, 145, 189 and 265 mm.

Is strobe timing published?

No. The controller category covers brightness and strobe control, but no frequency, pulse width or trigger timing is published for any model.

How long do the lights last?

At 25 °C with a white source at 50 % brightness continuously, expected reliable operating time exceeds 30,000 hours.

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Next Step

If you are specifying a replacement and need measured values for your own conditions — your sensor size, your working distance, your feature size — send us those four numbers and we will run them against the current catalogue and tell you what actually fits, including when nothing does.