R17 Longpass Filter
Long-pass filter blocking green-cyan (< 620 nm) while passing 92 – 94 % rich red light (660 – 770 nm) for warm, glare-free output.
- Red passband: 660 – 770 nm, 92 – 94 % T (± 2 – 3 % ripple)
- Cut-on (T50): ≈ 645 nm
- Edge steepness: ~25 nm (10 → 90 % transition)
- Blue-green blocking: < 1 % T below 620 nm
(~25 % bump @ 395 nm – suppressible) - Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: UV-ripple flattening, edge tuning, 45° AOI, rapid prototypes
Learn more
R17 keeps transmission below one percent up to about 620 nm, hits 50 %
near 645 nm, and clears 90 % by ~660 nm. It then rides a smooth 92 – 94 %
plateau through at least 770 nm with ripple confined to ± 2 – 3 %. A modest
25 % bump at 395 nm can be flattened in custom runs for absolute blue
suppression. The ion-assisted hard-oxide stack resists heat, humidity,
solvents, and repeated cleaning. KUPO coats Borofloat®, soda-lime, Schott
D263 T, or Corning Eagle XG in any outline—from 5 mm chips to 450 mm
plates, 0.21 – 3.8 mm thick—and can ship prototypes in about two weeks.
Typical uses: LED colour tuning, far-red fluorescence capture,
green-glare suppression in machine vision, daylight-to-tungsten warming
for film lighting, and AR/HUD red-graphic injection without blue-green
bleed.
Description
R17 keeps transmission below 1 % all the way to around 620 nm, climbs to the 50 % point near 645 nm, and tops 90 % by roughly 660 nm. From there it holds a smooth 92–94 % plateau to at least 770 nm with ripple limited to ±2–3 %. A small ~25 % bump at 395 nm can be flattened when absolute blue rejection is required. R17 is aimed at tasks that need clean, high-power red—warming LED luminaires, capturing far-red fluorescence, or stripping green glare from machine-vision paths—without stacking gels or extra optics.
Key advantages
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Sharp green–cyan cutoff – 50 % cut-on ≈ 645 nm; < 1 % T maintained through ~620 nm to minimise shorter-wavelength leak.
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High, flat red passband – 92–94 % T from ~660 nm to 770 nm keeps brightness and colour balance stable.
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Optional UV peek control – Modest 395 nm ripple can be suppressed for applications needing total blue blocking.
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Hard-oxide durability – Ion-assisted coating withstands heat, humidity, solvents, and repeated cleaning.
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Format versatility – Round, square, or custom blanks from 5 mm to 450 mm, thickness 0.21–3.8 mm, on Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG glass.
Typical applications
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LED colour tuning – Remove cool spikes in white or RGB fixtures to create warm, red-rich ambience.
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Fluorescence emission – Collect far-red probes (Cy5, Alexa 647, mPlum) while rejecting green–cyan excitation.
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Machine vision – Strip cyan reflections from reflective parts while keeping the red channel bright for defect detection.
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Photography & cinema lighting – Warm daylight LED panels toward a tungsten look without gels.
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AR / HUD optics – Inject red graphics cleanly, with negligible blue-green bleed toward the viewer.
Need a quick prototype or a high-volume run? R17 filters can be coated, diced, and shipped to your exact specifications—fast.
