Sandia Optical
Microlens Arrays

Microlens arrays — uniform illumination, structured-light projection, and wavefront sensing.

Microlens arrays solve uniformity and patterning problems that single optics cannot. We design and replicate them in volume from SPDT-cut inserts on our press floor, and we run direct SPDT for the prototype and low-volume parts that ride ahead of tooling.

Square · Hex · Freeform · Randomized
Applications

Five places programs reach for arrays instead of single optics.

Beam homogenization
Top-hat illumination for laser exposure, structured-light projection, and machine-vision lighting where intensity uniformity at the work plane is the design target.
Structured-light projection
Dot-pattern and grid projectors for depth sensing, biometric capture, and AR/VR tracking systems — array geometry tuned to the downstream pattern.
Displays and HUDs
Diffuser plates and integrator arrays for headlamp, HUD, and AR display systems where the eye sees uniform luminance regardless of source non-uniformity.
Wavefront sensing
Shack-Hartmann sensor arrays with custom pitch and focal length tied to the adaptive-optics or testing application the program is built around.
Fly's-eye condensers
Two-stage homogenizer architectures (fly's-eye condenser pairs) for high-uniformity output planes in photolithography, projection, and exposure systems.
Geometries

Square, hex-pack, freeform, randomized — each chosen by the uniformity and speckle budget.

Microlens array geometries A · Square Fill ≈ 78% Even diffraction orders B · Hex-pack Fill > 95% Best uniformity envelope C · Randomized Speckle-reducing Coherent-source illumination Pitch 30 µm – 5 mm · sag 5 µm – 500 µm · square / hex-pack / freeform / randomized Fabrication: SPDT-generated inserts for volume · direct SPDT for prototypes
Microlens array geometries — square, hex-packed, and randomized.

Pitch range: 30 µm to 5 mm. Sag range: 5 µm to 500 µm. Fill factors above 95 % achievable on hex-pack layouts. The choice between square and hex-pack is rarely about uniformity in isolation; it is about how the downstream optical train handles the higher-order diffraction lobes the array geometry produces.

Fabrication routes

Two routes — chosen by volume and the prototype-vs-production economics.

Mold replication via SPDT-generated inserts
Highest-volume route: SPDT cuts the master geometry on an electroless-nickel insert; the press floor replicates the array in polymer. Cycle-time and lot-economics scale to high volume once the cavity is qualified.
Direct SPDT
Prototype and low-volume route: arrays cut directly into the optical-grade polymer or metal substrate. Useful for design iteration, custom freeform geometries, and short-run programs where ramping a mold is not the right call.
Beam homogenization

A gaussian beam enters; a uniform output plane emerges.

Beam homogenization through a microlens array Incident beam Microlens array Homogenized output Gaussian Uniform intensity 5–10% non-uniformity Optical axis
Beam homogenization through a microlens array — animated; pauses under prefers-reduced-motion.
Uniformity budget

What "uniform" means in practice, and what drives the envelope.

  • Typical non-uniformity over the target plane: 5–10 % depending on geometry and tolerancing.
  • Hex-pack geometries give the highest fill factor (> 95 %) and lowest geometric non-uniformity.
  • Randomized layouts trade a small uniformity penalty for significant speckle reduction under coherent illumination.
  • Tolerances on pitch, sag, and registration cascade into the final non-uniformity envelope — modeled per program with Monte-Carlo at design time.

Send us the illumination profile and the target plane.

We will tell you which geometry — square, hex, freeform, randomized — gives the uniformity and speckle envelope your program needs, and which fabrication route the volume justifies.

Discuss an array program