Surface Figure
Surface form tested by interferometry — PV/RMS values from the actual measurement.
Choose by Configuration
Cemented Rod Lens Assemblies — Single to 4-Element
The right relay structure is decided by the drawing, not by a rule of thumb. We confirm single to 4-element configurations from your print and ship with ≤3′ centration and a measured COA. Send your drawing.
Questions buyers ask before ordering:
- "Which configuration is best?" — there is no preset answer; the structure depends on optical design, space and the system.
- "Can we buy single rod lenses only?" — yes, supplied as independent relay elements per drawing.
- "Can you make 3- or 4-element assemblies?" — yes, reviewed line by line from the drawing.
- "What if we are not sure?" — send the drawing; engineers confirm the structure, not a price band.
The Problem
Getting the configuration wrong is expensive — not the element count
Buyers are often pushed toward "more elements" as if it were automatically better. In practice the configuration must match the optical design and the system around it.
1 · Over-configuration. A more complex assembly than the system needs adds cost and lead time without improving the image.
How HSD prevents it: configuration is confirmed from the drawing before quoting — no preset upsell.
2 · Space mismatch. A larger cemented group may not fit the tube, fixtures or optical length — and the failure appears at assembly, not at the supplier.
How HSD prevents it: tube space, optical length and fixture fit are checked in the engineering review, before production.
3 · Terminology confusion. "Doublet", "triplet" and element counts are used differently between suppliers. The drawing — not the label — defines the structure.
How HSD prevents it: we confirm element count, material order and structure from the drawing line by line.
4 · Preset recommendations. Suppliers who recommend by price band instead of by drawing leave the buyer to absorb the mismatch.
How HSD prevents it: every configuration is reviewed engineer-to-engineer; samples and production run on the same locked structure.
What we make
One configuration decision, four capabilities
Configuration capability
| Configuration | HSD scope |
|---|---|
| Single rod lens | Independent relay element · per drawing |
| 2-element cemented | Two lenses, one fixed component |
| 3-element cemented | Three-element fixed combination |
| 4-element cemented | Four-element fixed assembly |
Tolerance capability
| Item | Specification |
|---|---|
| Diameter | −0.02/−0.04 mm (fit) |
| Length | Per drawing |
| Centration | ≤3′ (cemented per drawing) · ISO 10110-6 4/3′ |
| Surface | 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 |
More elements does not automatically mean better imaging. The configuration must match the optical prescription, sensor and available space.
System Matching
What to check with the system before choosing
Complex cemented assemblies should be reviewed together with the whole system. Before recommending a structure, HSD engineers confirm:
- Sensor resolution and pixel size
- Target field of view and working distance
- Optical length and available tube space
- Assembly datum and tolerances
- Target surface quality and centration
- Coating band
- Sample and production quantities
In-house production
Shop-floor photos
Production photo 1
Production photo 2
Production photo 3
Production photo 4
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
Which configuration is best?
There is no preset "best". The configuration depends on optical design, tube space, optical length, assembly tolerance and the sensor system. HSD confirms it from the drawing.
Can we buy single rod lenses only?
Yes. Single rod lenses are supplied as independent relay elements, with diameter, length, centration, surface quality and coating per your drawing.
Can you make 3- or 4-element assemblies to our drawing?
Yes, reviewed line by line: material order, radii, spacing, datum, cementing and overall tolerances are confirmed before quoting.
We are not sure which configuration we need.
Send the drawing. Our engineers recommend the structure from the optical design and space, not from a price band.
Will samples and production use the same structure?
Yes. After sample approval the process is locked; production repeats the same configuration and every batch ships with a measured COA.
Have a rod lens or assembly drawing?
Engineer-to-engineer configuration review · NDA protected · quote within 24 hours.
Application context
Cemented rod lens assemblies: single to 4-element
This page covers cemented rod lens assemblies, from single to 4-element builds, made to drawing with centration ≤3′.
Check on the drawing: element count, interface diameters, cement type and centration target.
Can you cement to drawing?
Yes, the assembly is made and measured per drawing; centration and interface are confirmed before production.
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
A local defect caught during a cemented assembly run — PV 1.126λ, stopped before shipping.
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