Surface Figure
Surface form tested by interferometry — PV/RMS values from the actual measurement.
Image Relay Optics
Precision Rod Lenses for Medical Endoscopes — Φ1.19–8.0 mm
Last reviewed: October 2026 · measured values from production batches
A few arc-minutes of centration error on one rod is magnified through 10–12 relay elements. We measure centration per ISO 10110-6 on every batch and put the numbers on the COA. Send the drawing and get a fit check within 24 hours.
We supply single rod lenses or a complete relay set for one scope model — rod lenses and rear rod lenses matched to the same tolerance system.
Applications: laparoscopes · arthroscopes · cystoscopes · hysteroscopes · ENT endoscopes · industrial borescopes
BBAR 400–700 nm (R<0.5%) optional · NDA before drawings · quote within 24 hours · MOQ 10.
We supply single rod lenses or a complete relay set for one scope model — rod lenses and rear rod lenses matched to the same tolerance system.
Applications: laparoscopes · arthroscopes · cystoscopes · hysteroscopes · ENT endoscopes · industrial borescopes
BBAR 400–700 nm (R<0.5%) optional · NDA before drawings · quote within 24 hours · MOQ 10.
Questions buyers ask before ordering:
- "Why did our image go soft at the edges?" — a small alignment error is magnified through 10–12 relay elements, and the failure only shows at final assembly, not at the lens supplier's inspection.
- "Is our supplier actually the manufacturer?" — some suppliers resell parts from several factories; when yield problems appear, there is nobody who can explain the root cause.
- "What does switching suppliers cost?" — re-qualification and re-tooling in the middle of production can run hundreds of thousands of dollars, plus months of delay on medical programs.
- "Can we trace a bad batch?" — only with measured values on every batch; otherwise lot-to-lot drift slips past incoming inspection and surfaces downstream.
Rod Lens Product Range
Choose the rod lens type or standard size you need
245 standard sizes from 1.19 mm to 8.0 mm OD. Review the size table and send the matching drawing or target dimensions.
Multi-element rod lens assemblies made to print, with cemented groups and batch inspection records.
Nine application pages: arthroscopes, hysteroscopes, cystoscopes, ENT, spine and nephroscopes, industrial borescopes.
Small-diameter relay rods for space-constrained endoscope designs.
Rod lens components for cystoscope relay systems.
Relay rods and assemblies for hysteroscope optical systems.
Rod lens manufacturing for arthroscope OEM programs.
Small-format rod lenses for ENT endoscope assemblies.
Rod lens components for spine and nephroscope relay optics.
Made-to-print rod lenses for industrial inspection optics.
Precision ground blanks for coating laboratories, supplied with measured batch data.
Make-to-print optics for endoscope assemblers, including coated and uncoated options.
Standard sizes
Frequently requested rod lens sizes
These are the standard sizes buyers ask for most often. Each one is made to print with the same diameter tolerance, centration method and batch COA as the rest of the range, and each size page lists the drawing points we confirm before quoting.
- Φ2.00 × 16.00 mm rod lens
- Φ2.00 × 22.90 mm rod lens
- Φ2.70 × 22.20 mm rod lens
- Φ2.70 × 22.90 mm rod lens
- Φ2.77 × 22.90 mm rod lens
- Φ2.78 × 22.95 mm rod lens
- Φ2.78 × 29.00 mm rod lens
- Φ3.49 × 29.00 mm rod lens
Looking for another dimension? The full list of 245 sizes is on the standard rod lens size table. Deutsche Fassung: Standardgrößen für Stablinsen.
The Problem
Four problems that show up too late — and how HSD prevents them
None of these are exotic. They are the reasons buyers re-qualify suppliers in the first place.
1 · Edge softness is an alignment problem. A few arc-minutes of centration error on one rod is magnified through 10–12 relay elements. The image fails at final assembly — at the far end of the train, not at the supplier's inspection bench.
How HSD prevents it: centration is verified on a per-batch sampling plan per ISO 10110-6, with measured values printed on the batch COA before parts leave the factory.
2 · The "manufacturer" may be a reseller. If your supplier outsources to several factories, nobody can explain a yield problem when it appears. The only fix is re-qualifying a second supplier and paying for it twice.
How HSD prevents it: we are the factory — a 30-person precision lens workshop in Nanjing. Your drawing is reviewed by our own engineers, not forwarded to a third party.
3 · Switching mid-production is the most expensive option. Re-qualification, new tooling and delays add up to hundreds of thousands of dollars — and on medical programs, a change can stall the project for months.
How HSD prevents it: your drawing is reviewed engineer-to-engineer before production starts, so the parts that ship match the design you approved — no surprises that force a switch.
4 · Batch drift is invisible until the image tells you. MTF, distortion or centration can shift slightly between lots, pass incoming inspection, and only surface in the assembled scope — where it is almost impossible to trace back to one batch.
How HSD prevents it: every batch COA carries measured values — dimensions, centration, surface quality — so drift is visible at incoming inspection, not at final assembly.
That is why we manufacture a relay train as one system: every element carries the same diameter tolerance, the same centration method and the same COA format — so assembly does not depend on anyone's feel.
Have a drawing? Get an engineer-to-engineer review.
Tolerances, coating and fit checked by our engineers — NDA protected, reply within 24 hours.
What we make
One relay train, four capabilities
Component capability
| Component | HSD standard range |
|---|---|
| Rod lenses | Φ1.19–8.0 mm · length 10–80 mm · 245 sizes |
| Rear rod lenses | Φ6 class · per drawing |
| Slim relay rods | Φ1.19–1.96 mm · per drawing |
| Uncoated rod lens blanks | For coating labs · per drawing |
Tolerance capability
| Item | Specification |
|---|---|
| Diameter tolerance | −0.02/−0.04 mm (fit) |
| Length tolerance | Per drawing |
| Centration | ≤3′ (cemented per drawing) · ISO 10110-6 4/3′ |
| 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% |
Measurement capability
| Item | Method |
|---|---|
| Centration | Horizontal-axis V-groove · ISO 10110-6 · per-batch sampling inspection |
| COA | 5 lines: part/dims/centration/surface/method |
| Batch | Measured values, not "within spec" |
Delivery capability
| Item | Commitment |
|---|---|
| MOQ | 10 pieces |
| Quote | Within 24 h of drawing |
| Confidentiality | NDA standard |
| System | ISO 9001:2015 |
In-house production
Production and inspection, in-house
Production workshop
Production workshop
Production workshop
Photos shown are HSD's own production examples. Customer designs are never displayed. Final specifications per the drawing confirmed with your engineer.
Why us
Why HSD
ISO 9001:2015
Manufacturer since 2009
Measured COA per batch
NDA standard
24 h quote
MOQ 10
FAQ
Common questions
Can you supply single rod lenses or a complete relay train?
Both. A complete train means every element shares one tolerance system, so assembly fits without rework.
What centration can you hold?
Rod lenses ≤3′; cemented assemblies per drawing. Every batch COA carries the measured value, taken on a horizontal-axis rig per ISO 10110-6.
What is the smallest rod lens you make?
Φ1.19 mm, one of 245 standard sizes. Smaller configurations are reviewed against the drawing.
Why is the diameter tolerance −0.02/−0.04 mm?
It is a fit tolerance — clearance for coating fixtures and tube assembly, so parts load without distortion and slide without sticking.
What are the lead time and MOQ?
MOQ 10. Quote within 24 hours of drawing confirmation; samples and production run on the same process.
What documents ship with each batch?
A five-line COA with measured values (part/print number, measured dimensions, centration, surface quality, test method) plus material certificates per batch.
Have a rigid endoscope rod lens drawing?
Engineer-to-engineer quote within 24 hours · NDA protected · MOQ 10.
Send your drawing / request a quote
Tell us what you need – quote your drawing number or send the drawing to rfq@hsdoptical.com. Technical review and quotation within 24 hours.
NDA protected – your drawings stay yours.
All drawings and specifications are treated as strictly confidential. We sign your NDA or ours before you send anything sensitive.
All drawings and specifications are treated as strictly confidential. We sign your NDA or ours before you send anything sensitive.
Request sent – securely
We reply within 24 hours. If you requested an NDA, we send it with our reply.
Inspection & Metrology
We measure it — and the numbers go on your COA.
Every batch is verified with interferometry, centration measurement and surface inspection. You get the actual measured values, not a “within spec” checkbox.
Centration
Centration checked on the centration station, typically ≤3′. The reading shown is from a real part — 2.02′.
Surface Quality
Surface and edge quality inspected under a video microscope — scratch/dig per MIL-PRF-13830B.
What “Pass” Looks Like
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 →
Real inspection record from this product line
Workstation measurement during rod lens production — PV 0.51λ.
Real measurement, kept on file. Your COA gets the same kind of data.
See the Factory Live — Schedule a Video Tour
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