Description

This exciting project centred on the development of a new LED board with an exceptional (market leading) light output to power consumption ratio, housed in individual modules connectable by an innovative power transfer system.

Challenge

The concept stage of the project established general objectives of modularity, high efficiency and a cost target allowing the product to compete effectively in the identified markets. It was not clear at this stage that these objectives could be achieved.

Technical objectives included achieving an LED board temperature of less than 20 degrees above ambient through correct heatsink design and a target of 7000 lumens output for the new board from a consumption of 60 watts of power.

Power would be transferred from module to module by means of “butterfly” connecting pieces which would also provide mechanical stability. A maximum of at least nine modules would need to be connectable to allow the product to be offered to challenging markets (e.g. large industrial compounds, sports fields).

The design of the LED board would also have to be undertaken in conjunction with the design of a new polycarbonate lens to try and achieve the required photometric value targets for the product to be commercially viable.

These objectives presented a considerable challenge and achievement of a successful outcome would only follow iterative prototyping.

Solution

The design challenges were placed into three categories:-

  • Mechanical engineering issues including design of the heatsink, butterfly connectors and housing in aluminium.
  • Specialist design of the LED board and lens.
  • Design of the power feed and electrical interface between the individual modules and the butterfly connectors.

Hallam worked with The University of Nottingham, on a consultancy basis to develop and provide a model for the calculation of the heatsink surface area required for any particular design to achieve the thermal transfer values required for a particular material. Hallam has the IP rights to this model and continues to use it in lighting development projects.

The mechanical design of the housing, heatsink and connectors was undertaken by Hallam’s own staff using professional CAD software. Heatsink extrusion prototypes (and the final component) had to be made outside the UK as the UK extrusion supply chain was unable to manufacture the required design.

The LED board prototypes and final version were manufactured by Seoul semiconductors to the specification provided. The polycarbonate lens was manufactured in the UK to the CAD model and specification provided.

Hallam’s staff designed and prototyped the power feed component and electrical interfaces using spring loaded connectors and seals.

Summary

Following independent regulatory testing and approval the finished product went on sale from the beginning of 2017 and has already been sold into industrial and commercial markets. Applications include dockside storage compounds, refrigeration plants and factory units. In addition systems have been sold to schools, golf courses and restaurants and there is evidence of interest from the domestic sector, where single modules provide effective patio/security lighting.