Overview

A precision optical aperture is the thin metal stop that defines a light bundle in cameras, projectors, spectrometers and laser systems, and its edge quality decides how much stray light reaches the sensor. Photo chemical etching cuts these blades and diaphragms from 0.02–0.5 mm stainless, nickel silver or beryllium copper, producing knife-sharp, burr-free edges with no recast layer, heat tint or mechanical stress. Because the whole aperture array is dissolved from a single masked sheet, even complex iris leaves and multi-hole masks repeat identically from the first article onward.

Stray-light control is where the process earns its place. Etched edges can be blackened by black oxide, matte blackening or PVD black chrome so the bevel does not glint, and a tight ±0.01 mm tolerance on aperture diameter keeps the f-number and field stop consistent across a batch. Designers can mix through-apertures, half-etched seating steps and alignment marks in one part; since geometry lives on the artwork rather than in a die, prototype iterations stay fast and low-cost.

Parameter Window

• Available Materials: 304/316L stainless, pre-blackened stainless, nickel silver, beryllium copper, Invar
• Material Thickness Range: 0.02–0.5 mm
• Tolerance: ±0.01 mm on aperture diameter, ±0.02 mm on blade profile
• Minimum Feature: 0.03 mm knife edge, 0.05 mm minimum blade width
• Surface Options: black oxide, matte blackening, PVD black chrome, electrophoretic black, anti-flare coating
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Optical Specification — Fix aperture diameter, f-number, edge radius and stray-light target from the optical layout.
2. Material Selection — Pick stainless, nickel silver or beryllium copper and set thickness against edge rigidity and the blackening method.
3. Cleaning & Lamination — Degrease the thin foil and laminate fine-grain dry-film resist for crisp edge definition.
4. UV Exposure — Expose the aperture, iris-leaf and half-etched step artwork through high-resolution glass tools.
5. Development — Open the aperture and contour areas, inspecting for resist scum that would round the knife edge.
6. Precision Etching — Etch from both faces under controlled undercut so the precision etching process yields a burr-free, stress-free edge.
7. Blackening & Stripping — Strip resist and apply black oxide or PVD black chrome for low-reflectance, anti-flare edges.
8. Optical Inspection — Verify diameter, edge radius, burr and reflectance under magnification, then pack in clean trays.

Core Advantages

1. Knife-sharp edges: Chemical removal leaves a clean bevel with no burr, recast layer or heat tint, so the aperture does not scatter light back into the path.
2. Stray-light control: Black oxide, matte or PVD black chrome finishes suppress edge glint and lower veiling glare at the sensor.
3. Tight diameter control: ±0.01 mm on aperture diameter keeps f-number and field stop consistent from sample to mass production.
4. Stress-free flat parts: No stamping force or laser heat means blades stay flat, preserving alignment in stacked iris assemblies.
5. Complex geometry in one piece: Through holes, half-etched seating steps and alignment marks are formed together without secondary machining.
6. Fast iteration: Geometry lives on the film, so diameter or iris changes are a new phototool rather than a new die.

Typical Applications

• Camera iris leaves: Diaphragm blades for still and industrial cameras with sharp edges and smooth, jam-free actuation.
• Projector stops: Field stops and baffles that suppress internal barrel reflections once blackened, lifting image contrast.
• Spectrometer slits: Entrance and exit slit plates whose width tolerance sets resolution and throughput, with burr-free edges.
• Laser path apertures: Pinhole stops inside and outside laser cavities that set beam diameter and strip edge modes.
• Microscope field stops: Field-limiting plates in illumination paths, burr-free to avoid diffraction artifacts.
• Sensor mask arrays: Multi-aperture masks for encoders and image sensors with hole positions registered to the array.

Design Notes & Process Considerations

1. Aperture and f-number: Fix aperture and f-number from the optical design before assigning tolerance; diameter error shifts throughput and depth of field.
2. Edge radius and sharpness: Call out the maximum allowed edge radius, since sharper edges stray less light but too thin a blade needs a thickness check.
3. Blackening and anti-flare: Specify the black oxide, matte or PVD black chrome system and reflectance target; coating must not eat into micro-hole diameter.
4. Flatness in stacks: For multi-leaf iris stacks, call out flatness and burr limits, since warp causes jamming or decentering.
5. Half-etched steps: State step depth and position, and whether a feature is half-etched or through-cut; give depth together with diameter.
6. Drawing completeness: Put diameter, tolerance, edge radius, blackening and flatness on one drawing to reduce approval rounds.