In 1907, Henry Joseph Round of Marconi Labs observed electroluminescence in silicon carbide crystals, which can be considered as the first indication of the LED phenomenon. Between 1920 and 1950, several researchers studied electroluminescence in semiconductors, but without making practical applications of it.

In 1961, Gary Pittman and James Robert Biard of Texas Instruments created the first practical infrared LED (890–900 nm).

In 1962, Nick Holonyak of General Electric, considered the "father of LED", manufactured the first visible red LED (650–700 nm).

Between 1962 and 1970, red-orange and yellow LEDs were developed. In 1972, George Craford of Bell Labs, a former graduate student of Holonyak, developed the first high-brightness yellow LED (585–595 nm) and improved the red LED to make it 10 times brighter.

We were the first company capable of designing and producing semiautomatic and automatic analysers using full-range LED optical systems, being at the forefront of technology. We launched the BTS-350, our first semiautomatic analyser with full LED optical system, in 2009.

Some features of our Smart LED technology optical systems are:

• They use a double beam design, with two silicon photodiodes, to achieve ultra-high stability, resolution and accuracy absorbance measurements, with a wide range.

• They have one dedicated LED for each wavelength. Therefore, they can individually control the light emission at each wavelength, achieving the suitable light intensity at all wavelengths to optimize the readings. In optical systems with halogen lamp, it is not possible to regulate the light intensity for each wavelength independently.

• They don’t need any refrigeration system of its light source, and they don’t require any warmup time. Therefore, they don’t slow down the start-up of the analysers, and the temperature of the light source does not affect the reactions temperature. Optical systems with halogen lamps need refrigeration for the lamp and have to wait for the temperature stabilization of its filament to get a stable light source.

• They have no moving parts and there are no mechanical adjustments, reducing drastically maintenance intervention. LEDs are switched at high speed, and the system can read, at the suitable light wavelength, 24 different biochemical reactions per second.

• They have a practically unlimited lifetime, and there is no need for light source maintenance. Halogen Lamps must be replaced every 1,000-2,000 hours.