You may have heard about the micro lens used for compact imaging devices. It is used in mobile phone cameras and photocopiers. It is a small lens, less than a diameter of a millimeter (mm). It could be as small as 10 micrometers (µm). The small-sized lenses offer a good optical quality using a simple design. However, the unwanted effects could develop because of optical diffraction at various small features. You should rest assured that a typical micro lens would be the single element entailing a plane surface. It would also have a spherical convex surface used for refraction of the light.
Benefits of smaller lens size
Due to the smaller size of the micro lens, the support offered by the substrate tends to be thicker than the lens. You should rest assured to consider it into the design. When it comes to using sophisticated lenses, you would need aspherical surfaces. However, others could use various layers of optical material for achieving their design performance. The different kind of microlens offers two flat and parallel surfaces. It would provide you the desired focusing needs by refractive index variation made across the lens. It would not be wrong to suggest that a few micro-lenses would meet their focusing action needs using the variation in the refraction index along with the use of the surface shape.
Different classes of micro lens
Yet another type of microlens would be the micro-Fresnel lenses. It would help the light focus through refraction in concentric curved surfaces. It would help you develop lightweight and relatively thin lenses. The binary-optic micro-lenses help you focus light using diffraction. The stepped and grooved edges provide you with an ideal shape. They offer several benefits in replication and fabrication through standard semiconductor processes.
What does microlens arrays entail?
Micro lens arrays comprise several lenses formed in a single-dimensional or dual-dimensional array on a substrate support. It would not be wrong to suggest that the circular apertures of the individual lenses are not allowed to overlap. Rather, they would be placed in a hexagonal method so that the substrate offers maximum coverage. For the remaining gaps between the lenses, you should create the micro-lenses using non-circular apertures.
Using the optical sensor arrays, you would help focus on the tiny lens system. It would concentrate the light onto the photo-diode surface.
The recent time’s witness micro-lenses in imaging chips. These have become relatively smaller to meet the needs of Smartphone devices.