Micro-lens Array

A micro-lens array is a critical optical component in modern image sensors, consisting of a precisely patterned grid of microscopic polymer or glass lenses. Each microlens corresponds to an individual pixel's photodiode. Its primary function is to collect and concentrate incoming light that would otherwise fall on non-photosensitive areas (like transistor circuitry and metal interconnects) and redirect it onto the active silicon photodiode region. This significantly increases the sensor's quantum efficiency, fill factor, and overall light sensitivity, which is essential for high-performance imaging in low-light conditions and for achieving higher resolution in compact camera modules.

In the manufacturing of image sensors, the micro-lens array is typically placed above the color filter array and planarization layer. The lenses are made from materials such as photosensitive resin (polymer), silicon dioxide (SiO₂), or silicon nitride (Si₃N₄). Key parameters include pitch (5–50 μm), lens diameter (5–50 μm), sag height (1–10 μm), focal length (5–100 μm), surface roughness (Ra ≤ 5 nm), form accuracy (PV ≤ 0.1 μm), transmittance (≥95%), operating temperature (-40–85 °C), storage temperature (-40–125 °C), relative humidity (≤85% RH), substrate thickness (200–1000 μm), and array size (1–20 mm). These values are typical ranges and must be verified for the specific model and application.

The micro-lens array is a component used in the assembly of image sensors. It is not a standalone product but is integrated into sensor modules. When selecting or specifying a micro-lens array, engineers must consider the pixel size, sensor stack thickness, and required optical performance. Verification of model-specific values and standards should be conducted with the legal manufacturer or supplier. The directory provides reference data only and does not imply certification or compliance.

Light incident on the image sensor surface first passes through the color filter array and then strikes the convex surface of each individual microlens in the array. Based on the principles of refraction, each microlens bends and focuses the light rays, concentrating them down through the planarization layer and onto the smaller, active area of the underlying photodiode. This process maximizes the amount of light captured by each pixel, improving the signal-to-noise ratio and the sensor's effective sensitivity.