microprismen

Microprisms are tiny prism-shaped optical elements, typically formed as arrays on a substrate. Base dimensions range from a few micrometers up to several millimeters, and the prisms are arranged in one- or two-dimensional grids. The facets are usually polished to reduce scattering, and the prisms can redirect, split, or homogenize light, or increase the effective optical path length within a material.

Materials and fabrication methods vary by application. The prisms are commonly made from transparent polymers such as PMMA or polycarbonate, but glass and silicon are also used. Manufacturing methods include embossing or hot stamping for polymers, injection molding for high-volume parts, glass molding or etching for glass prisms, and lithographic or laser-based micromachining for precise features. The choice depends on required optical properties, environmental durability, and cost.

Applications span several fields. In display technology, microprism sheets placed on backlights redirect light toward the viewer to improve brightness, efficiency, and uniformity in LCD or OLED panels. In photovoltaics, microprismatic coatings reduce surface reflectance and trap light to boost absorption. In imaging and sensing, microprisms can couple light into detectors, split light into channels, or form compact beam-shaping elements. They also appear in retroreflective materials and privacy screens where controlled scattering is useful.

Performance considerations include refractive index, facet angle, and surface quality, which determine losses and diffraction effects. Thermal and environmental stability, adhesion to substrates, and manufacturing tolerances influence long-term performance. Microprisms offer compact, flat optics with strong angular control, but can introduce chromatic dispersion or color shifts if not properly engineered.

Related concepts include microlens arrays and retroreflective prism sheets.