Freeform Optics Manufacturing Services

At Yighen Ultra Precision, we specialize in freeform optics manufacturing—turning complex, non-rotational surfaces into ultra-precise, manufacturable components. Freeform optics enable performance and packaging advantages that spherical or even aspheric optics cannot achieve.

Our engineers and machinists combine freeform optical design expertise with ultra-precision freeform surface machining—including 5-axis CNC milling, single-point diamond turning (SPDT), and advanced metrology. This allows us to fabricate surfaces with:

Form accuracy down to ±0.2 μm
Surface roughness below Ra 10 nm
Verified dimensional stability across full apertures

📩 Contact us: info@yighen.com — We reply within 24 hours

Why Freeform Optics Matter

Freeform optics break symmetry and enable new optical system architectures: compact folded relays, wide-field AR displays, customized beam shaping, and lightweight reflectors. They provide:

Compact, folded optical paths → reducing device size for AR/VR headsets and HUDs
Reduced component count → one freeform replaces multiple spherical elements
Tailored aberration control → off-axis performance and ghost suppression
Beam redirection → custom reflectors, prisms, and light guides

Traditional optics reach their limit when size, performance, or integration demand more. This is why freeform optical design and machining is now central to AR/VR, LiDAR, medical imaging, and aerospace systems.

Our Capabilities in Freeform Optics Machining

Capability Area	Specification
Surface Form Accuracy	±0.5 μm (typical); ±0.2 μm (advanced)
Surface Finish	Ra < 10 nm (optical grade)
Machinery	5-axis CNC, SPDT, ultra-flat fly-cutting
Materials Supported	PMMA, Zeonex, COC/COP, Optical Glass, Aluminum
Metrology & QC	Interferometry, profilometry, white-light scanning, CMM

All processes are run in climate-controlled labs, since even 1°C fluctuation can cause freeform optics to drift out of tolerance.

Prototyping Freeform Optical Components

What sets Yighen apart is our ability to rapidly prototype freeform optical components and then transition them into repeatable, scalable production.

Ultra-precision prototyping: Using diamond turning and 5-axis CNC machining, we can generate complex freeform optics with sub-micron accuracy, enabling proof-of-concept evaluation within days.
Design-to-prototype feedback: Our engineers integrate Optical System Design with real machining data to adjust freeform coefficients and ensure the prototype matches design intent.
Material flexibility: We prototype in both optical plastics (PMMA, COP, Zeonex) and optical glass, giving clients realistic insight into performance and manufacturability.
Accelerated path to production: Once validated, designs flow into Prototyping Optical Components and later Optical Assembly & Lens Modules.

This capability is essential for industries where freeform optics define product performance but time-to-market is critical.

Error Compensation Technology for Mass Production

Batch production of freeform optics, especially via injection molding of plastics, introduces challenges such as material shrinkage and deformation. Yighen has developed a proprietary freeform error compensation technology:

We model shrinkage behavior for specific polymers (PMMA, COP, Zeonex, etc.)
Compensation is applied directly into the freeform surface design
Machining of molds includes these pre-compensated geometries
The result: consistent, repeatable freeform optics with high yield in mass production

This ensures that what is prototyped in diamond turning matches what is delivered in thousands of molded parts—an advantage few freeform optics suppliers can offer.

Tools & Standards for Freeform Optics

Designing and machining freeform optics requires more than advanced machines—it requires integration of design tools, process control, and international standards. At Yighen, we rely on:

Design software: Zemax OpticStudio and CODE V to generate prescriptions with freeform coefficients and optimize imaging/illumination systems.
Illumination & stray-light modeling: LightTools for ray-trace simulations, ghost path analysis, and beam uniformity evaluation.
Metrology standards: ISO 10110 surface form specifications to communicate tolerances and roughness.
Manufacturability checks: coupling design data with diamond turning machine tool-path simulations and in-process metrology feedback.
Knowledge base: We follow methodologies documented in SPIE and OSA proceedings, ensuring alignment with industry best practices.

Freeform vs. Aspheric vs. Custom Design

Freeform surfaces are not the only path—sometimes aspherics or custom symmetric designs are better. We help clients choose the right solution.

Design Path	When to Use	Advantages	Learn More
Freeform Optics Design	Compact packaging, wide FoV, off-axis correction	Reduce elements, enable folded systems, beam shaping freedom	Freeform Optics Design
Aspheric Lens Design	Imaging and illumination requiring mature, cost-effective correction	Simpler manufacturing, fewer elements, lower cost	Aspheric Lens Design
Custom Optical Design	Unique requirements, detectors, or packaging	Tailored solutions balancing performance and integration	Custom Optical Design
Reverse Optical Engineering	Legacy optics with missing design files	Recover prescriptions and enable modern manufacturing	Reverse Optical Engineering

👉 This ensures every project is matched to the right design approach, with Optical System Design as the overarching framework.

Applications of Freeform Optics

AR/VR & Wearables
Freeform optics enable compact, lightweight architectures. We design and machine freeform prisms, combiners, and waveguides that reduce device thickness while maintaining image clarity. This often combines Optical System Design with prototyping freeform optical components for rapid iteration.

Automotive HUDs
Head-up displays demand wide FoV and perfect eyebox alignment. Our freeform projection mirrors are tailored to deliver precise geometry and stability, integrating error compensation technology for injection-molded parts in volume production.

Laser Beam Shaping
Homogenization and beam steering are best achieved with freeform refractive optics. We prototype freeform diffusers and collimators, then validate manufacturability through Tolerance Analysis & Athermalization.

Medical & Life Sciences
Freeform reflectors and imaging modules allow compact, distortion-controlled optics for surgical and diagnostic devices. Integrated Stray-Light & Ghost Analysis ensures maximum contrast and signal fidelity.

Defense & Aerospace
Ruggedized freeform optics reduce system weight while offering advanced off-axis correction. These are validated through Prototyping Optical Components and transferred into Optical Assembly & Lens Modules for mission-ready deployment.

Case Studies

1. AR Waveguide Prototype with Freeform Combiners
A client developing AR headsets struggled with bulky optics. We designed and prototyped freeform combiners that folded the optical path while maintaining >85% MTF across the eyebox. Rapid prototyping of freeform optical components using diamond turning confirmed feasibility, and our error compensation technology ensured injection-molded parts matched prototypes during volume production. See Prototyping Optical Components.

2. Automotive HUD Projection Mirror
For a European car maker, we fabricated a freeform curved mirror with ±0.2 μm form accuracy and Ra <10 nm finish. Traditional spherical mirrors caused ghosting and misaligned eye-boxes, but our freeform solution provided stable alignment across temperature cycles. Mass production tooling included pre-compensated molds, delivering 95% yield in molding trials. See Tolerance Analysis & Athermalization.

3. Freeform Beam Homogenizer for Lasers
An industrial laser system required uniform illumination. We delivered a freeform refractive element that redistributed beam intensity with <2% variation. Our team combined Stray-Light & Ghost Analysis with advanced metrology to ensure consistent performance in production.

4. Medical Imaging Module
A diagnostic device builder needed compact optics with low distortion. By integrating freeform-asphere hybrids, we reduced system size by 30% and improved resolution uniformity. Monte Carlo simulations validated yield, and the project was transferred into Optical Assembly & Lens Modules.

Frequently Asked Questions

Q1: What are freeform optics?
A: Freeform optics are non-rotational, non-symmetric optical surfaces that enable compact packaging, wide FoV, and advanced aberration correction.

Q2: How do freeform optics differ from aspheric lenses?
A: Aspherics are rotationally symmetric and mainly correct spherical aberration. Freeforms break symmetry, offering 3D beam shaping and off-axis correction. See Aspheric Lens Design.

Q3: Can freeform optics be prototyped quickly?
A: Yes. With diamond turning and CNC machining, we provide prototyping of freeform optical components in days, before scaling to molding. See Prototyping Optical Components.

Q4: How do you ensure freeform optics are manufacturable at scale?
A: We use freeform error compensation technology to pre-adjust mold geometries for polymer shrinkage, ensuring consistent mass production yield.

Q5: Which industries benefit most from freeform optics?
A: AR/VR, automotive HUDs, medical imaging, industrial lasers, and aerospace/defense. See Optical System Design.

Q6: What accuracy can you achieve?
A: Typical parts meet ±0.5 μm form error and Ra <10 nm surface finish. Advanced builds achieve ±0.2 μm accuracy.

Q7: Do you provide native design and machining files?
A: Yes. We accept STEP, IGES, STL, SolidWorks, and provide machining + metrology reports.

Q8: How do you validate freeform optics?
A: With interferometry, profilometry, white-light scanning, and BRDF-based stray-light evaluation. See Stray-Light & Ghost Analysis.

Q9: Can freeform optics be integrated into assemblies?
A: Yes. We design for manufacturability and then transfer validated optics into Optical Assembly & Lens Modules.

Q10: Do you reverse engineer freeform optics?
A: For legacy systems, yes—we reconstruct geometry through Reverse Optical Engineering.

Start Your Freeform Optics Project

📩 Email: info@yighen.com with your drawing, CAD model, or curvature map.
Tell us: wavelength, FoV, packaging, quantity, and timeline.
We reply within 24 hours.

🧭 Freeform Optics Manufacturing Process (5 Steps)

Define Requirements & Tolerances
Translate system targets (FOV, pupil, EFL, distortion, MTF @ lp/mm, WFE) into surface specs, material, coating, and inspection plan.
Pre-Shaping & Fixturing
Machine blanks/cores (CNC pre-shape, datum creation, centering) and design stable fixtures to control clamping and thermal drift.
Ultra-Precision Machining
Select the best path: SPDT/5-axis freeform fly-cutting for metals/plastics, or ultra-precision grinding for glass. Optimize toolpath, feed, depth of cut, spindle speed, and temperature.
Finishing / Polishing (As Needed)
Apply micro-polishing, MRF or deterministic finishing to reach target form (PV/RMS) and surface roughness (Ra in nm) without over-polish of local slopes.
Metrology & Closed-Loop Error Compensation
Measure with interferometry/white-light/profilometry; build a shape-error map; apply freeform error-compensation (incl. molding shrinkage correction) and iterate until spec is met.

⚖️ Prototyping vs. Mass Production – Quick Decision Table

Typical reference ranges for decision-making; exact capability depends on geometry, material, and aperture.

Attribute	SPDT / 5-Axis Freeform (Prototyping)	Injection-Molded Freeform (Mass Production)	Glass Grinding/Polishing (Precision Glass)
Best use	Rapid prototypes, small batches, metal/plastic masters	Scalable plastic optics, cost per piece ↓ at volume	High stability, IR/visible glass optics
Lead time	3–10 days (rush 48–72h possible)	Tooling 3–6 weeks; SOP after T0/T1/T2	2–6 weeks typical
Up-front cost	Low NRE	Tooling cost (mold/core); per-part cost low	Low-to-medium (fixtures & laps)
Form accuracy (PV)	≤0.10–0.20 µm (typical on small/medium parts)	≈0.20–0.50 µm after compensation（量产一致性强）	≤0.20–0.50 µm depending on glass & size
Surface roughness (Ra)	2–5 nm typical on SPDT plastics/metals	5–10 nm on optical-grade plastics	<5–10 nm with fine polish
Aperture / size	Small → medium（常见 ≤150 mm；更大需评估）	Per mold design; replicates 1k–100k+	Small → medium; large optics可定制
Materials	PMMA, PC, COP/COC（ZEONEX/TOPAS…），Al、Ni-P、Cu	Optical plastics（PMMA/PC/COP/COC/PMMI…）	Optical glass（含 CaF₂/MgF₂ 等）
Error compensation	Toolpath & spindle compensation	Molding shrinkage & deformation compensation（闭环）	Shape-error map + deterministic finishing
Unit economics	单件/小批性价比高	量产最优（10³–10⁵+）	取决于玻璃与工艺节拍
Typical hand-off	Prototype lens / master → molding	SOP locked, stable Cp/Cpk	Final glass optics for rugged use

CTA idea：Need help choosing a path? → Link to “Diamond Turning vs. Molding for Freeform Optics”.

❓FAQ – Freeform Optics

Q1. What are freeform optics?
A1. Freeform optics are non-rotationally symmetric optical surfaces engineered to control light in ways spherical/aspheric lenses cannot, enabling compact, high-performance systems for AR/VR, HUD, LiDAR and beam shaping.

Q2. How are freeform optics manufactured?
A2. Most parts follow a chain of pre-shaping → ultra-precision machining (SPDT/5-axis freeform) → polishing → metrology → error-compensation. For plastics, tooling is qualified first, then injection-molded in volume with shrinkage compensation.

Q3. What materials are suitable?
A3. Optical plastics (PMMA, PC, COP/COC/ZEONEX/TOPAS) for lightweight volume parts; aluminum/Ni-P/Cu for mirrors and masters; optical glass (incl. CaF₂/MgF₂) for stability and IR use.

Q4. How long does prototyping take?
A4. Typical freeform prototypes ship in 3–10 days depending on size/complexity; 48–72 h rush is possible for pre-qualified geometries and materials.

Q5. Can freeform optics be mass-produced?
A5. Yes. With injection molding + error-compensation, freeform plastics can reach consistent form and Ra at 1k–100k+ volumes with tight Cp/Cpk in SOP.

Q6. What drives cost the most?
A6. Geometry (slope & local curvature), aperture, material, coating, metrology coverage, and whether tooling is needed. Early DFM and tolerance budgeting cut total cost and lead time.