microlentes

Microlenses are miniature optical lenses, typically ranging from a few micrometers to a few tens of micrometers in diameter, arranged in dense arrays. They are designed to collect and concentrate light, improving the efficiency of optical systems by directing photons toward active regions.

In digital imaging sensors, a microlens sits above each pixel to increase the optical fill factor and guide light to the photodiode. This is particularly important for sensors with small pixel pitches or shallow sensor architectures, where a significant portion of incident light can be lost or redirected away from the active area. Microlenses help mitigate light loss from oblique incidence and improve overall quantum efficiency, especially in back-illuminated sensors.

Manufacturing and materials commonly used include polymers such as PMMA or SU-8, produced by molding, photolithography, or laser-writing techniques. Some microlenses are made of glass. Lens shapes are often plano-convex or aspheric to correct aberrations and maximize light arrival at the pixel wells. The lens array pitch is matched to the sensor’s pixel grid, and precise alignment is essential in high-resolution cameras.

Beyond imaging sensors, microlens arrays are used in solar panels to concentrate light onto smaller active areas, in LED and display modules to shape emission, and in plenoptic (light-field) cameras to capture directional light information. They also appear in micromirror and micro-optics assemblies within various optical instruments.

Advantages include higher light collection and improved sensor performance, while challenges involve manufacturing precision, lens alignment, and material stability under environmental conditions.