Quick answer: Etching Optical Glass covers Optical Glass (CTE 7.1 x 10^-6 /K, 350 nm – 2.0 um); Etching to depth control +/-1 um. Prototypes ship in 5-10 working days.
We etch Optical Glass daily, in thicknesses from 0.1 – 5 mm. The controlling numbers: depth control +/-1 um working tolerance, 10 um channel width (masked HF) minimum features, and isotropic smooth walls off the machine. Where the drawing asks for more, downstream lapping and polishing take over.
Specifications at a glance
| Material | Optical Glass (N-BK7, H-K9L and filter glass sets) |
|---|---|
| Thermal expansion (CTE) | 7.1 x 10^-6 /K |
| Service temperature | 400 C (Tg 557 C) |
| Transmission range | 350 nm – 2.0 um |
| Density | 2.51 g/cm3 |
| Knoop hardness | 610 kg/mm2 |
| Refractive index | 1.5168 @ 587 nm |
| Stock thickness | 0.30 – 50 mm |
| Maximum blank size | 300 mm diameter |
| Process | Etching |
| Working tolerance | depth control +/-1 um |
| Minimum feature | 10 um channel width (masked HF) |
| Surface finish | isotropic smooth walls |
| Thickness window | 0.1 – 5 mm |
| Edge condition | stress-relief etch available |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
What the process holds
Etching earns its place through microchannels, cavities and frosted textures without mechanical stress. Its boundary condition – isotropic undercut roughly equals depth, so masks are compensated at layout time – is the first thing our DFM review checks.
Beyond this page, Optical Glass routinely runs through cnc machining, drilling, coring, sandblasting in our shop – most real parts combine two or three of these steps.
Design guidance
Before sending the RFQ, check these against your drawing:
- Material note: index-certified blanks must be oriented and serialized through the shop to keep melt traceability.
- Process boundary: isotropic undercut roughly equals depth, so masks are compensated at layout time.
- Over-specification is the quiet budget killer: a 20/10 scratch-dig face costs roughly three times an 80/50 face, so grade each surface individually.
The full rules live in our tolerance design guide and holes and edges design guide.
Where these parts end up
Orders for etching optical glass cluster in optical sensors (sensor windows, filter caps, lens covers); machine vision (camera windows, ring-light diffusers, calibration plates); scientific instruments (reference flats, cells, prism mounts, stage inserts). Background reading on the underlying material science: RP Photonics: optical glass.
The fastest route to a quote is geometry: use the 3D configurator below, or the site-wide custom glass machining 3D builder for fully custom parts.
Related reading on this site: JGS1 quartz glass, optical glass options, high-purity quartz guide.
Common questions
What tolerances are achievable on Optical Glass parts?
Ground features hold +/-0.01 mm and lapped thickness reaches +/-0.003 mm. Index-certified blanks must be oriented and serialized through the shop to keep melt traceability.
What thickness range do you stock for Optical Glass?
Standard stock spans 0.30 – 50 mm, with blanks up to 300 mm diameter. Other formats are sourced per order.
How does Optical Glass behave under heat?
CTE is 7.1 x 10^-6 /K and continuous service reaches 400 C (Tg 557 C), which is what drives its use where certified refractive index and dispersion matters.
What accuracy does etching hold?
Depth control +/-1 um with minimum features of 10 um channel width (masked HF). Isotropic undercut roughly equals depth, so masks are compensated at layout time.
Specifications on this page were last reviewed by our engineering team in July 2026.