Introduction to micro lens arrays:  Micro-lens arrays can be defined as a combination of two or more small lenses (lenslet).  In most cases, the lenslet forms a periodic pattern of a square or hexagon. The number of micro lenses (lenslet) is usually thousands or millions. Microlens array is available as a separate optical component, in a mounted form. It is identified three forms- a thin transparent layer, homogenous glass, and semiconductor substrate.

Parameters of Micro Lens array: Before using or ordering a micro lens array, it’s important to know that each lens is different:

  • Micro lens is optimized depending on different spectral ranges, optical material, and the level of anti-reflection coatings.
  • It is available in different values of lens pitch- from a few micrometers to hundreds of micrometers. However, fields that involve accurate and delicate work such as medical science or photography require high accuracy of the lens position.
  • Each lens is characterized by its diameter, focal length, and the wavelength.
  • Lens is usually available in a circular or cylindrical shape. However, these shapes can be customized as per the customer’s request.

Micro Lens Fabrication: Lens array can be produced by various methods depending on the customer’s requirement. For instance, one may employ a micro-fabrication method to produce a micro lens in one step or can opt for photolithography where the lens pattern is defined by a binary photolithographic mask. The next step in the fabrication is to decide the type of material that fits the chosen production technique. Different optical materials such as fused silica, glasses, plastic, and polymers are used depending on the spectral range and thermal stability.

Application of Micro Lens array: Due to its robust features, Micro Lens arrays are used in several areas of modern optics and optical products:

  • To increase the light collection efficiency of CCD arrays.
  • Used in top-notch digital projectors, to focus light in the active areas of the LCD.
  • Advanced micro lens is used as concentrators in high-efficiency photovoltaics for electricity production.
  • Used in compact imaging devices such as photocopy machines and mobile-phone cameras.
  • As correction optics for high brightness and high power diode laser stacks.

Micro lens arrays can provide a dramatic increase in the performance of interline-transfer and CCD imaging due to its robust features. However, their success depends on the client’s specifications, its features and most importantly, the service of optic suppliers.