Light sources are critical components in many optical based analytical and scientific instrumentation and systems. The most common types are glass tube lamps such as Xenon, Mercury, Deuterium and Tungsten-Halogen. These lamps are located within the analysis system alongside a detection unit, usually a semiconductor-based or photomultiplier-tube detection device.
These lamps emit a broad and continuous optical spectrum, often extending from the IR (Infra Red) through the visible inito the Ultra-Violet (UV) region. Typical modes of operation for these optical systems include absorption, reflection, scattering and fluorescence monitoring. The lamps are relatively difficult to manufacture and as a result, they often display variations or inconsistencies in performance and are difficult to calibrate. On top of this, they have limited life spans, often of only a few hundred hours.
Despite these issues, lamps are considered a mature technology, accepted by the industry and to-date there has been no real effort to replace them. Until now there has been no viable alternative.
SquareLite™’s LED Technology
SquareLite’s SIMP-100 (free space) and SIMP-200 (fiber coupled) modules effectively provide an efficient wide spectrum light source which overcomes the above mentioned problems with lamp technology and brings all the benefits of LED technology to these analysis applications. These benefits of small size, high efficiency and low power consumption make the SIMP Modules specifically attractive for emerging applications in portable analysis and point-of-care diagnostics.
The SquareLite™ technology locates a number of LEDs inside what is effectively an integrating sphere (internally coated with Barium Sulphate). This causes the emission spectrum at the output slit to be a combination of all the LEDs’ spectra. The LEDs are selected such that their combined spectra gives a single continuous broadband spectrum. Additionally, the concept uses the idea of a pyramid structure which positions the LEDs which emit lower power closer to the output slit, ensuring that more of their power is extracted.
The controller supplied with the modules has 12 constant current sources and the array of LEDs are split across the 12 channels, enabling 1/12 of the emission spectrum to be dynamically switched on and off, adjusted or strobed, if required.
