BH-A29 Cold Mirror & Longpass Filter
BH-A29 is a cold mirror, near-IR longpass: transmission stays near baseline through ~300–690 nm (≤1 % T with a small UV bump ~370–390 nm), then rises steeply across ~710–760 nm to a high IR passband of ~94–96 % T from ~780–1,150+ nm with low ripple—reflecting VIS, passing IR.
- Function: VIS-reflecting / NIR-transmitting longpass (cold mirror)
- VIS leakage: ≤1 % T to ~690 nm; small UV bump ~370–390 nm
- Edge position: Rapid 10→90 % rise across ~710–760 nm
- IR throughput: ~94–96 % T from ~780–1,150+ nm; low ripple
- Durability: Low-scatter hard dielectric; abrasion & humidity resistant
- Substrates & format: Borofloat®, Eagle XG, D263 T, or soda-lime; 5–450 mm • 0.21–3.8 mm; rear-AR & slight wedge options
Learn more
BH-A29 reflects visible back into the beam while venting IR to dumps or sensors—cooler optics and higher luminous efficiency. The steep long-wave edge cleanly separates paths, and the smooth IR passband delivers predictable power to thermal or sensing channels.
Typical applications • Illumination optics & light engines (reflect VIS, vent IR heat) • Projectors & cinema lamps (protect phosphor wheels/LCD/LCOS) • Microscopy & biomedical lighting (cooler epi-illumination, head-lamps) • Machine-vision illuminators (deliver IR to sensors, keep VIS out) • Architectural & entertainment lighting (boost visible output, manage fixture temperature).
Need test chips tomorrow or thousands next quarter? BH-A29 cold-mirror longpass filters are coated and cut-to-size (including dicing) to your exact spec—fast.
Description
BH-A29 is a cold mirror, near-IR longpass. It reflects the visible band and passes infrared: transmission stays near the baseline through ~300–690 nm (generally ≤1% T with a small UV bump near ~370–390 nm), then rises steeply across ~710–760 nm to a high IR passband of ~94–96% T from ~780–1,150+ nm with low ripple.
Key advantages
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High IR throughput — ~94–96% T from ~780–1,150+ nm delivers strong thermal and sensing power.
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Steep long-wave edge — rapid rise across ~710–760 nm cleanly separates reflected VIS from transmitted IR.
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Low VIS leakage — near-baseline transmission across the visible supports efficient cold-mirror operation.
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Cooler systems — reflect the light you want, pass the heat you don’t for lamps, projectors, and light engines.
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Durable dielectric stack — abrasion and humidity resistant for field, stage, and lab use.
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Flexible glass choices — Borofloat®, Eagle XG, or D263 T (0.21–3.8 mm) for high-temp duty to ~450 °C; soda-lime for ≤150 °C. Custom sizes 5–450 mm; rear-surface AR and slight wedge available to suppress ghosts.
Typical applications
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Illumination optics & light engines — reflect bright VIS into the beam while venting IR heat.
-
Projectors & cinema lamps — protect phosphor wheels, LCD/LCOS engines, and dichroics from thermal load.
-
Microscopy & biomedical lighting — cooler epi-illumination and head-lamps.
-
Machine-vision illuminators — deliver IR to sensors while keeping VIS out of the path.
-
Architectural & entertainment lighting — boost visible output and manage fixture temperature.
Need test chips tomorrow or thousands next quarter? BH-A29 cold-mirror longpass filters are coated and cut-to-size (including dicing) to your exact spec—fast.
