Microlens Array (MLA) General Specification Sheet

Microlens Array (MLA) General Specification Sheet

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While every microlens array (MLA) project is custom by nature, tailored to the optical, mechanical, and environmental demands of the end application, Holographix offers the following general specifications as a helpful reference for system designers and engineers. These values represent typical performance targets or standard process capabilities across a wide range of successful MLA programs.

If your requirements push the boundaries of these standard specifications, whether in curvature precision, feature size, material compatibility, or integration, we encourage you to contact a Holographix Application Engineer. Our team can help evaluate feasibility, recommend design modifications, and guide you through the co-development process to ensure optical performance is both achievable and repeatable.

Please consider these specifications as general design guidelines. Actual capabilities will depend on the specific combination of design parameters, substrate selection, and fabrication process used.

Optical Specifications

Optical Specifications

Parameter Typical Value / Range Notes
Lens Diameter 10 μm – several mm Below ~10 μm diffraction becomes dominant; large diameters limited by sag
Lens Pitch 10 μm – 1 mm Not a hard limit; pitch affects fill factor and transition zone area
Transition Zone Width ~1 μm (varies with sag/steepness) Reduces usable lens area as pitch decreases
Sag Height 0.5 μm – 250 μm (process dependent) Limits focal power; defines manufacturing range
Radius of Curvature (RoC) Design dependent (short RoC = higher power) Tolerance typically given as RMS error to best-fit sphere/profile
RoC Uniformity (Intra-array) ±2–5% variation typical Across lenses on the same part
RoC Repeatability (Part-to-Part) <2% typical With stable tooling and process control
Surface RMS Error <0.1 μm typical; <0.05 μm achievable Relative to design profile (sphere or freeform)
Numerical Aperture (NA) 0.05 – 0.95 (informational) Related to RoC and refractive index
Surface Roughness <10 nm RMS (optical grade); <3 nm for low-scatter optics Higher values lead to forward scatter
Autofluorescence Low (material dependent) Avoid high-fluorescence resins for biosensing/imaging
Internal Transmission >92% across target band (material dependent) Fused silica best; polymers vary
AR Coating Reflectance <1.5% per surface (single-layer); <0.5% (multilayer) Limited by coating stress and substrate thermal budget
Mirror Coating Reflectivity Al: ~90%, Ag: 95–99%, Au: 98–99%,  Dielectric: 99%+ Depends on wavelength and application

Mechanical Specification

Mechanical Specifications

 

Parameter Typical Value / Range Notes
Substrate Material Glass, polymer (e.g., PMMA, epoxy), hybrid stack Material choice impacts durability, transmission, autofluorescence
Profile Shape Capability Spherical, aspherical, freeform, cylindrical No cost or complexity penalty across these using modern processes
Lens Sag Control ±0.1 – ±1.0 μm depending on height Sag defines focal power and process limits
Pitch Tolerance ±0.2 – ±2.0 μm Alignment-critical applications (e.g., image sensors)
Lens Height Consistency <±1 μm typical across array Important for focal plane uniformity
AR Coating Thickness 50 nm – 2um typical Minimize layers to reduce mechanical stress
Mirror Coating Thickness 100 nm – 2um Process dependent; uniformity critical on curved profiles

 

Environmental Specifications

See Polymer General Specifications

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