
Surface Figure
Surface form tested by interferometry — PV/RMS values from the actual measurement.
1 · Long rods have long cylindrical surfaces. One scratch or dig in the middle of a 46 mm rod is easy to miss and hard to polish out — and it lands in the image path.
How HSD avoids it: surface is checked to 40/20 MIL-PRF-13830B / ISO 10110-7 5/40-20 and recorded on the batch COA.
2 · Centration decides the relay. Each relay rod has to pass the image straight down the bore; centration error compounds rod after rod.
How HSD avoids it: centration is verified on a per-batch sampling plan per ISO 10110-6, with measured values on the COA.
3 · The “manufacturer” may be a trader. When drawings move through several shops, nobody can explain a repeatability problem.
How HSD avoids it: we are the factory — a 30-person precision optical workshop; your drawing stays with our engineers.
4 · Batch drift kills repeatability. A “within spec” COA hides lot-to-lot shifts that surface as field failures.
How HSD avoids it: every batch COA carries measured values — dimensions, centration, surface, test method.
Industrial builds need rods that behave the same batch after batch — same tolerances, same method, same COA format.
Production photos of long relay rod lenses, labeled by length. Final specifications per your drawing.




Scope of supply: relay rod lenses (lengths up to 46 mm) · slim relay rods · rear rods · uncoated rod lens blanks — all make-to-print per your drawing.
| Item | Specification |
|---|---|
| Rod lens diameter range | Φ1.19–8.0 mm; relay lengths 10–80 mm (per drawing) |
| Diameter tolerance | −0.02 / −0.04 mm (fit) |
| Centration | ≤3′, tighter per drawing |
| Surface quality | 40/20 · MIL-PRF-13830B / ISO 10110-7 5/40-20 |
| Edge chipping | ≤0.05 mm, per drawing · ISO 10110-7 E 0.05 |
| Coating | BBAR 400–700 nm, R<0.5% (per drawing) |
| Glass | Per drawing: JGS1 / H-ZF / H-LAK / H-K9L / N-SK15; material certificates with each batch |
| Length tolerance | Per drawing |
Centration is measured per ISO 10110-6 (≤3′, tighter per drawing) and the measured value goes on the COA — not a "within spec" line. Photo: our inspection bench.
You send the drawing, we make the rod lenses — NDA protected, MOQ 10. If we can't do it, we'll tell you why.
Send Your Drawing →Email [email protected]Application context
Industrial borescope rod lenses are specified by drawing because tube length, working length and relay count vary by instrument. This page is the make-to-print route for those drawings.
Check on the drawing: tube length, relay count and working diameter; no model number is needed.
No. A drawing or sample specification is enough; we review geometry, tolerances and surface quality from the drawing.
Inspection & Metrology
Every batch is verified with interferometry, centration measurement and surface inspection. You get the actual measured values, not a “within spec” checkbox.

Surface form tested by interferometry — PV/RMS values from the actual measurement.

Centration checked on the centration station, typically ≤3′. The reading shown is from a real part — 2.02′.

Surface and edge quality inspected under a video microscope — scratch/dig per MIL-PRF-13830B.

A passing surface from a production run: PV 0.51λ, RMS 0.059λ. Rejects never leave the workshop.
Measured COA per batch — ask for a sample COA with your quote. · Learn how to read a surface map →

Scratch measurement at the workstation — PV 2.876λ.
Real measurement, kept on file. Your COA gets the same kind of data.
Watch rod lens grinding, polishing, centration measurement and final inspection in real time. All information shared during the tour is confidential — your NDA is welcome.
Schedule a Live Video Tour