Converter technology for infrared emitters is being used by Osram Opto Semiconductors to produce an LED that emits broadband infrared light in a wavelength range from 650-1,050nm. The main application is near-infrared spectroscopy, such as analysing food to measure fat, protein, water or sugar content.
This broadband infrared LED – the SFH 4735 – is based on a blue chip and a special phosphor converter. The main application for the LED component is near-infrared spectroscopy for analysing food quality. With the SFH 4735, Osram Opto Semiconductors states that it has succeeded in producing the world's first broadband emitting infrared LED. This development from Osram enables this sensor technology to move into the consumer sector, for example, as an add-on for smartphones. The first mini spectrometers have already been showcased, and the LED means that a compact light source is now available.
Measuring freshness with a smartphone
Infrared spectroscopy uses the characteristic absorption behavior of certain molecular compounds. If a defined spectrum is directed at a sample, it is possible to determine the presence and quantity of certain ingredients from the wavelength distribution of the reflected light. This method is used in the food industry and in agriculture, among other sectors. It is possible, for example, to measure the water, fat, carbohydrate, sugar or protein content of foodstuffs. This data provides an indication of freshness, quality or calorie content.
The infrared LED opens this measurement technique up for the consumer market. One option is a compact sensor – like a USB stick – that would be used with an appropriate smartphone app to measure calories, freshness or nutritional content.
Converter for infrared emitters
The basis of the SFH 4735 is a blue 1mm2 chip in UX:3 technology. Its light is converted into infrared radiation with the aid of a phosphor converter developed specifically for this application. A residual blue component in the light helps users target the area they want to investigate. The emission spectrum of the SFH 4735 has a homogeneous spectral distribution in the infrared range. The chip is mounted in the compact Oslon Black Flat package which has strong thermal resistance.
Food analytics supplements bio monitoring
Compact units for spectroscopic chemical analyses open up a range of applications in consumer electronics. Experts expect that it will be possible in the near future to integrate spectrometers directly in mobile devices. The technology is a natural extension of bio monitoring, in other words, the trend for measuring various vital signs such as pulse rate and calorie consumption. A smartphone spectrometer will enable users to monitor the food they eat in a similar manner. Medicines can also be checked in the same way.
“Future applications are also of particular interest,” said Chris Goeltner, Product Marketing Manager for Infrared at Osram Opto Semiconductors. “It is conceivable that the emission range can be extended to include wavelengths up to 2,000 nanometers, which is the middle infrared spectral range. This will allow more precise and detailed measurements and will open up new options for everyday analyses of certain environmental parameters such as air quality.”