A European consortium, Delphi4LED, supported by the ECSEL Joint Undertaking – the Public-Private Partnership for Electronic Components and Systems, a funding programme of the European Union, with the financial support of the national funding authorities of the participating countries involved in the consortium – has found a new way of thinking, a new way to develop efficient lighting solutions, particularly for the automotive and general lighting markets, both of which are experiencing impressive revenue growth, predicted to reach around $37.3 billion in 2023. This consortium is composed of 15 partners, companies and research labs representing the total LED value-chain, offering added-value optoelectronic knowledge. 

Addressing design process inefficiencies

Similar to what already exists for power electronic components, but modified for LEDs, the consortium has demonstrated the feasibility to use multi-domain LED component models for LED-based product design, and have proposed new standards and methodologies for the solid-state lighting industry, from component characteristics measurements, through to product integration. By identifying appropriate optical and thermal characterisation test procedures, a mathematical formulation of the multi-domain model and an e-datasheet neutral-file format, Delphi4LED aims to address design inefficiencies for lighting products that exist today, which limit optimisation and slow down the whole product creation process. It is currently the time and effort involved in gathering, reverse engineering and extracting the necessary information to be used for the simulation of the thermal-optical behavior of an LED, in a given end user environment, that leads at best to increased design costs, and at worst to simulation not being performed, with a subsequently increased risk of design goals not being met or identified during physical prototyping. It is exactly these risks and inefficiencies Delphi4LED aims to address.

A multi-domain LED model requires both predictive accuracy, as well as the transparency of proprietary information regarding the LED package’s construction and material properties. Delphi4LED intends to address these requirements:

• Developing a test procedure to determine optical and electrical characteristics, at a series of prescribed, operating LED chip junction temperatures

• Identifying a set of temperature aware optical-electrical functions, the parameters for which are extracted directly from measurement

• Identifying a representation of a thermal network topology, and a method to extract its thermal resistances and thermal capacitances

Reducing cost in product design 

The Delphi4LED partners have conducted many investigations, and today results are available that will enable the design and production of more reliable and cost effective LED-based lighting solutions. Comparisons of new test methodologies and product design processes has delivered savings of up to 40 per cent. This includes the testing of components, product development time and material such as aluminum used for heat sinks.

LED manufacturers as key enablers 

Currently, inefficiency is inadvertently supported by integrators and end users, which should cease. LED manufacturers are, therefore, expected to adopt the newly developed methodologies, and to swiftly make multi-domain models and an e-datasheet neutral-format file that records components available to LED module and luminaire manufacturers. 

As part of their activities, the partners have conducted standardisation activities concerning test methods of LED packages, characteristics presentation and model interfaces, having lately made significant progress within JDEC and CIE appropriate committees. An important milestone has been passed in 2019 by these committees towards balloting updates of test standards and their final technical reports. These standardisation activities have created a momentum, building and now paving the way toward a quick adoption of this new design methodology by the lighting industry to the benefit of the end user.