What substrate should I choose - Borofloat®, Eagle XG, D263 T, soda-lime, or others
Choosing the right glass substrate is crucial for your project's performance and budget. Should you use Borofloat®, Eagle XG, D263 T, soda-lime, or another type? Here's a quick comparison to guide your decision:
Glass Substrate Comparison
| Property | Borofloat® | Eagle XG® | D263® T | Soda-lime | Others |
|---|---|---|---|---|---|
| Type | Borosilicate | Alk. earth borosilicate | Borosilicate | Soda-lime-silicate | Fused silica, aluminosilicate |
| Thermal Resist. | Excellent | Good | Good | Fair | Fused silica: best |
| Chemical Resist. | Excellent | Good | Excellent | Fair | Borosilicate: usually best |
| Transparency | Very high | Very high (>90%) | Very high (~92%) | High | Typically high |
| Therm. Expansion | Low | Moderate | Low | Higher | Lower = better |
| Typical Uses | Optics, lab, harsh env. | Displays, electronics | Sensors, microfluidics | Windows, bottles | UV (fused silica), high strength (aluminosilicate) |
| Cost | Medium | Med-High | Med-High | Low | Specialty: high |
| Flatness | Excellent | Excellent | Excellent | Good | Adv.: ultra-precision |
| Thickness | 1.1–21+ mm | Ultra-thin options | 0.03 mm+ ultra-thin | Wide | Varies |
Quick Guide
- Borofloat®: Best for high chemical and thermal resistance.
- Eagle XG®: Top choice for display panels, eco-friendly.
- D263® T: Excellent for ultra-thin, flat, and precision uses.
- Soda-lime: Cheap and widely used for non-critical jobs.
- Specialty: Choose fused silica for UV, aluminosilicate for strength.
Key Takeaway
- Pick based on performance and budget. Use borosilicates or Eagle XG® for demanding jobs; soda-lime for basic needs.
- Always check datasheets for specs before final selection.
Frequently Asked Questions
https://www.kupooptics.com/en/blogs/q-a/glass_substrate
What glass substrates are used for optical filters and how do I choose?
Common substrates: BK7 (cost-effective, good VIS-NIR transmission, standard choice), Fused Silica (UV-transmission down to 180 nm, low CTE, ideal for UV applications), Borosilicate (similar to BK7, good thermal stability), and specialty substrates like Schott B270 for displays. Choose based on wavelength range, thermal stability, and budget.
What is the difference between BK7 and fused silica as filter substrates?
BK7: Good transmission from ~350 nm to 2.5 µm, low cost, good machinability. Fused silica (FS): transmits from ~180 nm to 2.5 µm (UV-grade), much lower coefficient of thermal expansion (CTE) than BK7, harder, and more expensive. Use FS when UV transmission or thermal stability is critical.
How does substrate thickness affect optical filter performance?
Thicker substrates provide better mechanical rigidity but add more bulk absorption (relevant for UV or IR applications). Thinner substrates are lighter and have less absorption, but are more fragile and may bow under coating stress. Standard filter substrates are typically 0.5–3 mm thick.
What substrate should I use for NIR/SWIR optical filters?
For NIR (700–1100 nm): BK7 or fused silica. For SWIR (1–2.5 µm): Fused silica (cuts off around 2.5 µm). For MWIR (3–5 µm): Silicon or ZnSe. For LWIR (8–14 µm): Germanium or ZnSe. Substrate transmission must span the entire filter wavelength range.
