Infrared emitters for the photovoltaics sector

Drying, sintering and string soldering – the manufacture of solar cells requires heat in many of the individual production steps. Infrared radiation is a high energy, contact-free method of heat transfer. This saves time and production space. The benefits of infrared heat can also be realised under extreme process conditions. Thanks to a newly developed quartz reflector, heating processes can be carried out significantly better in vacuum or at high surrounding temperatures.
Heraeus Noblelight showed infrared emitters with the new reflector at the “Photovoltaic Technology Show 2007 Europe” which took place at the beginning of April in Munich.
Infrared emitters are very compact and transmit large amounts of energy without the need of a contact medium. This makes heating processes under vacuum possible and also helps to ensure that valuable production space is used more efficiently. Compared with metal tube emitters, the heating sources which have conventionally been used under vacuum conditions, Heraeus Noblelight infrared emitters have higher power density and are significantly more responsive. As a result, heating stages can be carried out faster and in a more controlled manner. At the PV Expo, visitors to the Heraeus stand could see a newly developed reflector of opaque quartz glass in operation. A module, which had been specially built for the exhibition, demonstrated that the reflector allows heat to be focused directly onto the product and gave visitors some idea of how energy can be saved with the improved process.
Infrared emitters with quartz reflectors are already being used in the manufacture of solar cells. They heat carrier materials before or during coating especially effectively, because these processes take place under vacuum or at very high temperatures.
The new reflector can also quickly successfully adjust to new applications. For example, it can be used in the application of the Si-N layer or for pre-heating during the diffusion or sputtering process or for drying of substrates. It has been shown that, with the use of the infrared emitter with the new reflector, process parameters such as temperature or operating time can be better maintained.
Opaque Quartz glass sets the standards
Unlike conventional reflectors, the new quartz glass reflector is not made of gold or metal oxides but of opaque quartz glass. Quartz glass is extremely heat-resistant, as well as being resistant to attacks from acids, lyes and other aggressive substances.
A gold coating on the infrared emitters reflects the radiation very effectively, to the extent that the effective radiation onto the product is almost doubled. Measurements have shown that the opaque quartz material has a reflectivity of around 60 to 70%. This is less than gold but similar to that of a highly polished aluminium reflector. However, an aluminium reflector progressively loses its reflectivity, as, over time, aluminium oxide builds up on its surface. In contrast, Quartz glass forms no such oxide coating over time.
The new reflector sits directly on the emitter and, unlike an external reflector, there is no additional fitting necessary to fix it in position.

Heraeus Noblelight GmbH, with its headquarters in Hanau and with subsidiaries in the USA, Great Britain and China, is one of the technology- and market-leaders in the production of specialist light sources. In 2005, Heraeus Noblelight had an annual turnover of 79 Million € and employed 644 people worldwide. The organisation develops, manufactures and markets infrared and ultraviolet emitters for applications in industrial manufacture, environmental protection, medicine and cosmetics, research, development and analytical laboratories.
The precious metal and technology organisation Heraeus, is a market- and technology-leader, worldwide, in the fields of precious metals, dental materials, sensors, quartz glass and specialist light sources. With a turnover of over 9 milliard € and with more than 10,600 employees worldwide in more than 100 companies, Heraus has been acknowledged worldwide for more than 150 years as a precious metals and materials specialist. The high innovation and development potential in the organisation is promoted and encouraged intensively and in a targeted fashion. Heraeus is consolidating its leading position in various industrial sectors by customer-focused product development and considered and targeted acquisitions.

Heraeus Noblelight GmbH
Reinhard-Heraeus-Ring 7
D-63801 Kleinostheim
phone +49 6181 35 8545
hng-infrared@heraeus.com

Press: Dr. Marie-Luise Bopp
marie-luise.bopp@heraeus.com

This release was published on openPR.