光学窓用広帯域反射防止コーティング

Broadband AR coating is used to reduce reflection across a wide wavelength range instead of a single design wavelength. It is suitable for optical glass, fused silica, quartz, sapphire, CaF₂, MgF₂, ZnSe, germanium, silicon and glass-ceramic substrates.

Available coating bands include VIS 400–700 nm, NIR 700–1100 nm, VIS-NIR 400–1100 nm, UV-VIS 350–700 nm, UV-VIS-NIR 350–1100 nm and extended NIR 600–1600 nm. Coating design can be customized by wavelength range, substrate, angle of incidence and reflectance target.

What Is Broadband AR Coating?

Broadband anti-reflection (BBAR) coating is a multi-layer thin-film design optimized to minimize surface reflectance simultaneously across a wide wavelength range — typically spanning 100 nm or more — rather than at a single design wavelength. Unlike a V-coat, which achieves extremely low reflectance (< 0.2%) at one specific wavelength but rises sharply on either side, a broadband design uses a more complex layer stack (typically 5–9 layers) with graded refractive index transitions to distribute the destructive interference condition across the full target band. The trade-off is a slightly higher minimum reflectance compared to a V-coat, but with dramatically better uniformity across the spectrum. This makes BBAR coatings the standard choice for white-light imaging systems, broadband laser platforms, multi-wavelength instruments, and any optical system where performance must be maintained across a range of wavelengths rather than optimized for a single line. Deposition is performed by ion-beam sputtering (IBS) or magnetron sputtering with real-time optical monitoring, ensuring layer thickness accuracy to ±0.5 nm and coating uniformity within ±0.5% reflectance across a 200 mm substrate.

コーティング性能仕様

Design Band	波長範囲	Ravg	Rmax
VIS BBAR	400～700 nm	< 0.5%	< 1.0%
NIR BBAR	700～1100 nm	< 0.5%	< 1.0%
VIS-NIR BBAR	400～1100 nm	< 1.0%	< 1.5%
UV-VIS BBAR	350 – 700 nm	< 0.8%	< 1.2%
UV-VIS-NIR BBAR	350 – 1100 nm	< 1.5%	< 2.0%
Extended NIR BBAR	600 – 1600 nm	< 1.0%	< 1.5%
Custom BBAR	Customer-specified	Design-dependent	Design-dependent

Layer count: 5–9 layers · Thickness accuracy: ±0.5 nm · Uniformity: ±0.5% R across 200 mm · AOI: 0°–30° standard

対応基材

	基板	代表的な等級
1	溶融石英	コーニング 7980 / 東ソー ES-2000
2	石英ガラス	SCHOTT Lithosil Q / Heraeus Suprasil 1
3	ホウケイ酸ガラス	パイレックス 7740 / ボロフロート 33
4	光学ガラス	BK7 / N-BK7 / N-SF11 / N-LAKシリーズ
5	サファイア	C面／A面
6	CaF₂	UV対応グレード／IR対応グレード
7	MgF₂	UV対応グレード
8	ZnSe	CVDグレード
9	ゲルマニウム	単結晶／多結晶
10	シリコン	フロートゾーン／チョクラルスキー法
11	結晶化ガラス	ZERODUR / PYROCERAM 9606

層構造と設計

デザイン	層の材料	層数	堆積法
VIS BBAR	TiO₂ / SiO₂	4 – 5	IBS / マグネトロン
NIR BBAR	TiO₂ / SiO₂	4 – 5	IBS / マグネトロン
VIS-NIR BBAR	Ta₂O₅ / SiO₂	6 – 7	IBS
UV-VIS BBAR	HfO₂ / SiO₂ / MgF₂	5 – 6	IBS（イオンアシスト）
UV-VIS-NIR BBAR	Nb₂O₅ / SiO₂ / MgF₂	7 – 9	IBS
Extended NIR BBAR	Ta₂O₅ / SiO₂	5 – 7	IBS / マグネトロン

All designs optimized via needle synthesis and transfer matrix method · Custom AOI and substrate available

代表的な用途

Scientific Imaging: VIS-NIR BBAR on microscope objectives and spectrometer optics for broadband detection
Machine Vision: VIS BBAR on industrial camera lenses for consistent throughput across white-light illumination
Multi-Wavelength Laser Systems: VIS-NIR BBAR on shared-aperture optics handling 532 nm, 1064 nm, and 1550 nm simultaneously
Astronomy & Telescope Optics: UV-VIS-NIR BBAR on corrector plates and field flatteners for broadband sky surveys
Defense & Surveillance: Dual-band VIS/NIR BBAR on sensor windows for day/night imaging systems
Photovoltaics: UV-VIS-NIR BBAR on solar concentrator lenses and cover glass for maximum light harvesting

環境および耐久性基準

テスト	状態	標準	結果
接着	テープ剥離試験	MIL-C-48497A	剥離なし
摩耗	50ストロークの消しゴム	MIL-C-48497A	コーティングの剥離なし
湿度	95% RH · 49°C · 24時間	MIL-STD-810	水ぶくれが生じない
温度サイクル試験	–65°C ～ +125°C · 10サイクル	MIL-STD-810	ひび割れ・剥がれなし
塩霧	5% NaCl・35°C・24時間	MIL-STD-810G	腐食なし
レーザーによる損傷	1064 nm・10 nsパルス	ISO 11254	LDT > 5 J/cm²
溶解度	蒸留水・24時間の浸漬	ISO 9211-3	解散なし