Bandpass vs Longpass Filters: How to Choose: custom precision glass machined to drawing with inspection reports. Single-piece prototypes to production volumes, quoted from your drawing.
The bandpass vs longpass filters: how to choose decision is really about band isolation versus edge separation. The short version: bandpass to isolate a signal line; longpass to separate emission from excitation.
Side by side
| Bandpass Optical Filters | Longpass Optical Filters | |
|---|---|---|
| Specification | CWL 200 – 1600 nm, FWHM from 1 nm, blocking OD4 – OD6 | cut-on 400 – 1500 nm, slope < 2% of edge |
| Role | isolate one working band for a detector | pass long wavelengths, block excitation light |
The decision axis is band isolation versus edge separation. Bandpass to isolate a signal line; longpass to separate emission from excitation.
Specification advice
Before sending the RFQ, check these against your drawing:
- 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.
For the complete framework, see the tolerance design guide and the holes and edges design guide.
Who orders this
bandpass vs longpass filters: how to choose shows up across semiconductor equipment (view ports, wafer carriers, plasma rings, chamber windows); led packaging (groove covers, phosphor carriers, package windows); microfluidic devices (chips, manifolds, via plates, bonded stacks).
Prefer to sketch it? Our custom glass machining 3D + 2D builder accepts your dimensions directly and routes them to engineering.
Engineers scoping this work usually also review beam splitter glass, ITO coated glass, ITO coating process.
Common questions
How fast can prototypes ship?
Machined prototypes ship in 5 – 10 working days. Coated or bonded parts add 1 – 2 weeks depending on queue slots.
What files do you need for a quote?
A dimensioned PDF plus DXF or STEP geometry. If only a sketch exists, our drawing review service formalizes it before quoting.
Do parts ship with inspection data?
Dimensional reports, surface certificates and material certs per melt are available; specify the level on the RFQ.
Which should I choose?
As a rule: bandpass to isolate a signal line; longpass to separate emission from excitation. Borderline cases are worth a materials review with our engineers.
Specifications on this page were last reviewed by our engineering team in August 2026.