Radial Fresnel Lenses
Written by Microsharp
PDF Print E-mail

Radial Fresnel lenses are used to focus or collimate light. Applications include solar concentrators and LED lighting.

Fresnel lenses reduce the amount of material required compared to a conventional lens structure by breaking the lens into a set of concentric angular sections known as Fresnel zones.

fresnel_lens_1

Lens Construction

Fresnel lens structures are be formed onto the surface of thin film materials using a UV embossing process to produce thin, flexible lens structures. Whilst the individual factets in our lenses are small, the very high precision with which we can form the individaul optical factets allows us to produce lenses with efficiency performances as good as or better than the best lenses produced by alternative technologies such as hot embossing or injection moulding.

The lens structure is constructed with a fixed height of between 35 and 70 microns and variable pitch. Facet peak and trough precision is usually in the region of 1-2 microns.

frenel_lens_3 

These lenses can then be bonded onto a PMMA support sheet if required.  

fresenl_lens_4  

Multiple lens parquets can be produced with parquet sizes up to 900mm by 1000mm.

fresnel_lens_5 

Optical Design and Modelling

Microsharp offers a comprehensive lens design service to develop lens designs to meet individual customers' exact specifications. Using proprietary software tools, we are able to design and model all aspects of CPV optics systems quickly and accurately.

Our design and modelling service includes the following parameters.

  • Focal length and focal spot size optimisation
  • On axis optical efficiency measurement / Off axis tolerance analysis
  • Optimisation of lens structure to align performance characteristics to individual multi junction sub cell characteristics.
  • Colour Mixing
  • Secondary optics design and dimensioning and integration
  • Complete optical train development

fresenl_lens_7            fresnel_lens_8

Lens Design Specifications

We design, develop and manufacture bespoke lenses for use in HCPV applications within the constraints given in the table below. The majority of the lenses we produce are bespoke designs and propriertay to the developing client.

We provide a comprehensive design and modelling service to ensure that each lens is optimised within the constraints set by a clients system. We can also design and model complete optical systems including secondary optical devices. 

 

 The table below outlines the normal the typical parameters within which we design. 

fresnel_lens_6

 Evaluation and development samples

Whilst most of our lens designs are proprietary to individual customers we do have a limited range of designs that we can make availabel to clients for evaluation purposes. Please contact us for details.