Introduction to the types of microlens array

The applications of Microlens array are very wide nowadays, from small printers to large scientific research, medical and industrial. In different applications of the environment, need to use different structures of microlenses, this article gives the types of Microlens array to introduce the different types of pictures.

Microlens array can be categorized mainly according to the following dimensions:

-According to the structural arrangement:

Single-row: microlenses are arranged along a single direction.

M×N arrangement: microlenses are arranged in two dimensions according to a matrix of M rows and N columns.

Full spread type: the microlenses cover the whole array area densely and uniformly, without obvious row and column intervals.

-According to the number of array faces:

Single-sided array: all microlenses are located on the same plane or surface.

Double-sided array: microlenses are distributed on two opposite surfaces of the array, which may be used to enhance optical performance or achieve special functions.

-According to the working principle:

Refraction-based Microlens Array (ROE): Based on the geometrical optics principle of refraction, the difference in refractive indices of materials directs light to bend and focus. These arrays are usually made of transparent materials (e.g. glass, plastic) and their shape and thickness are designed so that the incident light forms separate focusing points under each microlens, ultimately achieving spot overlap and beam homogenization at the focal plane.

Diffractive Microlens Array: The use of nano or micron-sized periodic relief structures on the surface to modulate the phase of light waves to achieve focusing or other beam manipulation through the diffraction effect. These arrays are characterized by thinness, lightness and design flexibility, and are suitable for applications such as wavefront sensing, light fusion, and light shaping.

-According to the shape characteristics:

Planar Microlens array: all microlenses are located in the same plane, the optical axis is parallel to each other, commonly used in light field cameras and CCD sensors.

Curved microlens array: microlenses are distributed in curved surfaces, similar to the structure of insect compound eyes, with large viewing angle, high resolution and other advantages.

-According to the lens shape and arrangement pattern:

Shape: Subunit shape can be circular, square, rectangular, hexagonal, quadrilateral or other specific shapes. Convex and concave microlenses can be combined with different arrangement shapes.

Arrangement pattern: usually arranged in a square grid, but can also be arranged in a hexagonal or other regular pattern, such as hexagonal aperture planar Microlens array.

Our Microlens array are classified into three main categories: A, B and C.

-A is a columnar microlens, A1 is a single convex columnar microlens, A2 is a single concave columnar microlens, A3A4 columnar Microlens array, A5 concave columnar Microlens array, and A6 concave-convex columnar Microlens array.

-B is a single microlens, B1 single convex microlens, B2 single concave microlens.

-C is a concave-convex microlens array, C1 concave microlens array, C2 concave square arrangement microlens array, and C3 concave square arrangement microlens array. lens array, C2 convex microlens array, C3 concave square aligned microlens array.

There are also some more specialized microlenses as shown below:

Class D is a more special microlens, usually customised models, D1 is a double-column round microlens, D2 is a custom-positioned microlens E1 is a concave square arrangement of square microlenses, E2 is a circular arrangement of microlenses

Note: The ML series microlens array are cost-effective product line. Mainly used for Medical beauty, Shack Hartmann sensor, High sensitivity imaging, Wavefront sensing, Beam focusing and some other applications. Due to the limited level of our cleanroom in old factory, there are always some defects (bad spots) on the surface of ML series products. The surface accuracy is also not very good.

The MLA, MLA1 and CLA, CLA1 series are high-end product line. MLA, MLA1 and CLA, CLA1 series microlens array have more accurate surface and less surface defects. They could be used for different applications, such as beam shaping (beam homogenization) and Industrial grade light field camera.