"HT" & "HTultra" Glass

Product Information

Optical glasses with ultra-high transmittance

As part of its extensive portfolio of optical glasses, SCHOTT has been offering special glass variants that are known for their superior transmittance. These special glass types with significantly improved transmittance are identified with the suffix "HT" or "HTultra". They are especially suitable for digital projection and high-end optical systems.

Our current portfolio includes 13 "HT" and "HTultra" glasses, (e.g. N-BK7HT, N-SK2HT). Several of our glass types exhibit the best transmittance values available in the maket, including:

N-BAK4HT
N-LASF9HT
N-LASF45HT
N-SF57HTultra
N-SF6HTultra

"HT" and "HTultra" glasses are provided as raw material, as pressings and in the form of finished components.

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Advantages

Improved transmittance especially in the blue-violet spectral range
→ improves color contribution and causes better mesoptic vision
Reduced 'thermal lensing effect' due to higher transmittance
→ reduces energy absorption and improves image quality
Faster polimerization of UV active glues due to better UV transmittance
→ time savings while processing
High product quality due to stringent quality control procedures
Excellent application support and expertise
Extensive processing capabilities (e.g. CNC machining, coating, polishing, sub-assembly)
Product range specifically suited for long-term availability

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Supply Forms

"HT" and "HTultra" glasses are available as:

Supply Forms*	Dimensions*
Components polished prisms lenses	10 mm - 200 mm 3 mm - 200 mm
Pressings	diameter: 5 mm - 320 mm center thickness: 2 mm - 100 mm
Raw glass strips blocks	≤ 50 mm 190 mm x 180 mm x 140 mm

* Other supply forms and dimensions upon request (depend on glass type).
Please contact us.

We also offer high-precision optical components made of "HT" and "HTultra" glasses.

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Technical Information

Specifications | Overview of High Transmittance Glasses

Specifications

Glass	n_d	v_d	τ_i**	Color Code
N-BK7HT	1.51680	64.17	0.998	33/29
N-SK2HT	1.60738	56.65	0.996	34/30
N-BAK4HT	1.56883	55.98	0.993	36/32
F2HT	1.62004	36.37	0.996	35/32
N-LASF45HT	1.80107	34.97	0.886	43/35
SF6HT	1.80518	25.43	0.941	41/36
N-SF6HTultra	1.80518	25.36	0.887	43/37*
N-SF6HT	1.80518	25.36	0.877	44/37
SF57HTultra	1.84666	23.83	0.924	39/36*
N-SF57HTultra	1.84666	23.78	0.830	40/37*
N-SF57HT	1.84666	23.78	0.793	41/37*
N-LASF9HT	1.85025	32.17	0.843	40/36*

additional variants
* wavelength for transmittance 0.7 and 0.05
** 10 mm thickness, 400 nm wavelength

Overview of High Transmittance Glasses***

*** Whereas the internal transmittance curves of standard optical glasses in the datasheet comprise median values for the glass types, "HT" and "HTultra" glass internal transmittance curves are guaranteed minimum values for internal transmittance in the visible spectrum. Shown graphics are valid for 25 mm sample thickness.

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