TECHNOLOGY — OPTICS
The right light distribution starts with the right optic.
VALDUR can be configured for footpaths, local roads, coastal environments, park paths, lit trails and sensitive natural environments through careful selection of lens, light distribution and colour temperature.
OPTICS EXPLAINED SIMPLY
The lens determines where the light lands.
An LED module emits light in all directions. The lens (optic) collects and directs that light so it lands where it is needed — on the road surface — rather than dispersing into the air, onto buildings or up towards the sky.
The same luminaire can produce entirely different results depending on which lens is chosen. A narrow footpath needs a narrow, elongated light pattern. A wide carriageway needs a wide distribution. The wrong optic can cause glare, dark patches between columns or unnecessary spill light beyond the road edge.
VALDUR uses LEDiL’s 2×2 lens platform — five different light distributions and three lens families that can be combined to suit the environment, mounting height and requirements.
WHY OPTICS MATTER
Right optic — light lands on the road surface, evenly distributed, with minimal spill light.
Wrong optic — glare, dark patches, light thrown onto buildings or into woodland.
Optics also affects the choice of colour temperature, column height and column spacing.
TAILORED TO THE ENVIRONMENT
Which optic goes where?
Each environment places different demands. Here is a concise guide — simple explanation first, technical depth for those who want to go further.
Footpath & cycle path
Even light along a narrower path. The light follows the path rather than dispersing sideways.
Technical detail
The T2 lens gives a narrow but elongated light pattern (Type II, long reach). Suitable column height 4–5 m, spacing 20–25 m. Gives low glare risk if the luminaire is correctly mounted. AMBER or SPECTRE suits residential areas where blue light reduction is desired.
Local road
Wider light pattern for carriageway and road edge. Suits most residential and local roads.
Technical detail
The DWC lens (Type III, asymmetric) is the most common choice for general urban lighting. Column height 5–7 m. Asymmetric distribution directs light outwards from the column. High efficiency (>90% with STRADA). Not available in SPECTRE variant; choose AMBER-DWC for a warmer tone.
Coastal & open environments
Controlled light pattern where spill light and glare must be minimised. Consideration for darkness is important.
Technical detail
In open, wind-swept locations, mounting height is decisive for how much light spreads into the surroundings. Lower mounting height (5–6 m) with T2 or DWC gives better control than a tall column. AMBER lens is recommended for coastal communities where darkness and wildlife are considered.
Lit trail
Light that follows the trail without throwing too much light into the woodland on either side.
Technical detail
The T2 lens gives a narrow, forward-directed light pattern suited to narrow trails. Typical mounting height 4–5 m. AMBER-T2 or SPECTRE-T2 reduces blue light and spill light towards surrounding nature. Avoid T4 and DWC where the trail is flanked by vegetation.
Nature-sensitive environments
Warmer light and controlled distribution to reduce impact on wildlife and dark environments.
Technical detail
AMBER lenses block ~99% of blue light (380–500 nm) and create a CCT of approximately 2,250 K from a 3,000 K LED. Combined with T2 optics and a low mounting height, this gives minimal impact on nocturnal wildlife. Suitable near Natura 2000 areas and nature reserves.
Wide roads, squares & car parks
Maximum width coverage for areas requiring even light across large widths.
Technical detail
T4 (Type IV) gives extremely wide distribution — suited for wide carriageways and open areas. ME (Class M) adds a back-light component and meets CIE M-class uniformity requirements. Both require taller columns (6–8 m) to avoid glare. Risk of spill light beyond the road edge — check mounting angle.
THREE LENS FAMILIES
Same form, different light pattern.
All lenses in VALDUR are based on LEDiL’s 2×2 platform (50×50 mm). You first select the light distribution (T2, DWC, T4…) and then the lens family based on requirements for light output and blue light reduction.
STRADA
Clear white lensEfficiency
Blue light reduction
Colour tone effect
Input CCT maintained unchanged
Clear lens that transmits almost all light. Maximum light output. Used when high lux levels are required and blue light does not need to be filtered.
Suitable for: Traffic routes, industry, harbours, high light level requirements
Not suitable for: Nature areas, over-specified residential streets
AMBER
Yellow filterEfficiency
Blue light reduction
Colour tone effect
3,000 K → ~2,250 K — noticeably warmer
Yellow-tinted lens that filters out ~99% of blue light (380–500 nm). Reduces light output by ~26–27%. Suitable when blue light reduction is more important than maximum lux.
| LED CCT | LED only | AMBER lens | Output |
|---|---|---|---|
| 2 200 K | 1 900 K | ||
| 2 700 K | 2 100 K | ||
| 3 000 K | 2 200 K | ||
| 4 000 K | 2 500 K | ||
| 5 000 K | 2 800 K | ||
| 5 700 K | 2 900 K | ||
| 6 500 K | 3 000 K |
LED source (left) compared with output through AMBER lens (right) — seven LED CCT options
Suitable for: Parks, residential areas, nature reserves, coastal environments
Not suitable for: Installations with high lux level requirements
Internal spectral filter
Visually similar to STRADA — the effect is measured in the spectrum, not visible to the naked eye
SPECTRE
Spectral conversionEfficiency
Blue light reduction
Colour tone effect
3,000 K → ~2,200 K; 4,000 K → ~2,500 K
Converts blue light to longer wavelengths instead of absorbing it. Higher light output is retained compared with filtering. Available variants: T2, SCL, ME, T4 (not DWC).
| LED CCT | LED only | SPECTRE-Y | Output |
|---|---|---|---|
| 2 200 K | 1 850 K | ||
| 3 000 K | 2 200 K | ||
| 4 000 K | 2 500 K | ||
| 5 000 K | 2 700 K | ||
| 6 500 K | 2 800 K |
LED source (left) compared with output through SPECTRE-Y lens (right) — five LED CCT options
Suitable for: Larger roads, squares, car parks where both high lux and low blue light are required
Not available: DWC variant does not exist in the SPECTRE family
FOR THOSE WORKING WITH LIGHTING CALCULATIONS
Compare optics
Data from LEDiL data sheets and the optics reference guide. The table shows all five light distributions with their properties and recommendations.
| Optic / Beam | Best suited for | Light pattern | Typical column height | Strength | Limitation |
|---|---|---|---|---|---|
DWC Type III |
Local roads, residential streets, general urban lighting | Asymmetric, medium width, long reach | 4–7 m | Universal choice, high efficiency (>94% with STRADA) | Not narrow enough for tight footpaths. No SPECTRE variant. |
T2 Type II |
Footpaths, cycle paths, narrow roads, lit trails, boulevards | Narrow, elongated, long reach | 4–5 m | Extremely even lighting along narrow stretches. Low glare risk. | Too narrow for wide carriageways. T2 with AMBER suits nature areas well but gives ~27% lower lux. |
SCL Type II/III extra long |
Wide roads, long column spacing, motorways | Very wide and elongated | 6–8 m | Enables long column spacing. Efficient at high mounting heights. | Risk of non-uniformity at low mounting heights. Requires careful lighting design. |
ME Class M |
Wide roads with high uniformity requirements, area lighting | Medium width with back-light component | 6–8 m | Meets CIE M-class. High uniformity (high Uo). Back light gives good coverage behind the column. | Back-light component can cause spill light if luminaire is aimed incorrectly. Requires correct design. |
T4 Type IV |
Squares, car parks, wide open areas, tunnels | Extremely wide distribution | 5–8 m | Maximum width coverage. Suitable where wide distribution is the primary requirement. | High risk of spill light beyond the carriageway. Can cause glare if not mounted high enough. |
EFFICIENCY & SPECTRUM
STRADA, AMBER and SPECTRE — what sets them apart?
| Lens family | Optical eff. | Blue light remaining | CCT shift |
|---|---|---|---|
| STRADA (clear) | >90–94% | All | None |
| AMBER (yellow) | ~73–74% | ~0.3–0.4% | 3,000 K → ~2,250 K |
| SPECTRE-Y | >88% | Nearly none | 4,000 K → ~2,500 K |
Source: LEDiL data sheets and product documentation. Measured with Philips Fortimo FastFlex 2×2 DA UHE and Nichia LED.
Simulated installation scenarios
| Scenario | Height | Spacing | Centre lux | Min lux |
|---|---|---|---|---|
| A | 5 m | 25 m | 10–20 lx | >0.5 lx |
| B | 4 m | 20 m | 15–30 lx | ~1 lx |
| C | 6 m | 30 m | 5–10 lx | 0.5–1 lx |
Calculated with ~1,000 lm (Fortimo FastFlex 4,000 K) and Type II/III profile. Exact values vary with lens choice. Use IES files and DIALux for final design.
GLOSSARY
Good to know
Light distribution
Where the light lands on the ground. A narrow distribution concentrates light along the road; a wide distribution spans a larger area.
Glare
When light strikes the eye instead of the surface. Excessive intensity in the field of vision reduces visibility. Most commonly occurs at too-low mounting height or with the wrong optic.
Uniformity (Uo)
The difference between bright and dark patches. High uniformity (Uo close to 1.0) means light is distributed evenly. Low uniformity creates dark pockets between columns.
Spill light
Light that ends up where it does no useful work — onto building facades, into woodland, up towards the sky. Increases energy consumption and negatively affects environments and wildlife.
Column spacing
The spacing between columns affects which optic works. Long spacing requires a lens with long reach (T2 or SCL). Short spacing gives more freedom.
Optical efficiency
What proportion of the light output from the LED module comes out through the lens. STRADA >90%. AMBER ~73%. SPECTRE ~100% (by converting blue light to visible).
IESNA Type
North American classification of light distribution width (Type I–V). Type II = narrow, Type III = medium, Type IV = wide. Used in IES files and lighting calculation software.
CCT (colour temperature)
Measured in Kelvin (K). Low values (2,200–3,000 K) give warmer, more amber light. High values (4,000–5,000 K) give cooler, whiter light. The AMBER lens lowers CCT by approximately 750 K.
Isolux diagram
A map of light levels on a surface, where lines connect points of equal illuminance (lux). Used to assess coverage and uniformity in a project.
WHY OPTICS IS ESPECIALLY IMPORTANT IN VALDUR
The luminaire can be adapted. It should be.
VALDUR is built for a long service life, but the right optic determines how well the light actually works in the project. A luminaire with the wrong lens may meet requirements on paper but deliver a poor experience in reality.
The combination of optics, colour temperature, controls and mounting height should be seen as a system. The right optic can reduce spill light, improve uniformity and make the installation more energy-efficient — without adjusting power output or the number of luminaires.
Because VALDUR uses LEDiL’s standardised 2×2 platform, the lens can be changed without replacing the luminaire — giving flexibility over time if requirements or the environment changes.
The lens affects more than the light pattern
Colour temperature (AMBER/SPECTRE), blue light profile, glare risk and luminous efficacy are all affected by lens choice.
Five distributions, three lens families
15 possible combinations. Not all suit all environments — which is why it is important to choose based on actual requirements.
IES files available for design
Photometric files in IES and LDT format can be requested for each power and optic combination. Use DIALux or Relux for verification.
FREQUENTLY ASKED QUESTIONS
About optics & lens selection
Can I change the lens without replacing the luminaire?
Yes. VALDUR uses LEDiL’s standardised 2×2 platform (50×50 mm). All lens variants — STRADA, AMBER and SPECTRE — share the same footprint and can be mounted on the same holder, making it possible to adapt the optics at a project change without replacing the entire luminaire.
What happens to light output if I choose an AMBER lens?
The AMBER lens filters out approximately 99% of blue light, but in doing so absorbs ~26–27% of the total light output. An LED module of 1,000 lm thus gives approximately 730–740 lm out through an AMBER lens. If the project requires high lux levels and low blue light simultaneously, SPECTRE is preferable — it retains almost full light output.
When should I NOT use the T4 lens?
T4 (Type IV) gives extremely wide distribution and is not suitable for narrow roads, footpaths or environments with sensitive areas on the sides (such as nature reserves or residential facades). The wide light can cause glare and spill light beyond the road edge. Choose T2 or DWC for most residential environments.
Is the SPECTRE lens available for all light distributions?
No. SPECTRE-Y-2X2 is available in the variants T2, SCL, ME and T4. There is currently no SPECTRE variant for DWC (Type III). If you need DWC distribution with reduced blue light, choose AMBER-2X2-DWC and expect approximately 26–27% lower light output.
How do I choose column height and column spacing?
Column height and spacing depend on optic, road width and uniformity requirements. The T2 lens at 5 m/25 m typically gives centre 10–20 lux with min >0.5 lux. Closer mounting (4 m/20 m) gives 15–30 lux. Footpaths and lit trails typically use 4–5 m with T2 optics. For final layout, lighting calculations in DIALux or Relux with current IES files are required.
READ FURTHER
Related technologies
ALSO READ IN THE KNOWLEDGE BASE
NEXT STEP
Request the complete technical documentation.
IES files, lighting calculation data and technical data sheets for each optic and power combination.