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May I put in my 2 pence worth, for what is worth!
As everybody knows or may not know is that LED technology has been around for 100 years or so, not in the form as we know it but the technology is not new. Nearly every country has dabbled at it at some point but never really knowing what to do with it, until recently!
It was in the 1960’s that they began experimenting again with this technology with a view to make money out of it. The early SLR camera’s had low current LEDs installed as battery condition indicators at the rear of the camera’s. These were really pin head size LEDs, they used very little current and lasted for years. In fact, I still have some old Pentax and Nikon camera’s where LEDs were used in the VF prism to let you know if you were under or over exposing, I just put a battery to one camera and the LEDs were still working fine. These are very low current diodes and only work in dark or low light conditions, infact they are useless for anything else.
In the mid 1980’s they experimented with the technology until they came up with improved semi conductors, which means that the current could be raised, with the introduction of Germanium, Selenium and Silicon semi conductors, this meant that you could raise the current that would be enough to excite diode to increase the brightness, so now the application changed so that LEDs could be used to illuminate but the boffins in white coats could not find a market for medium current diodes. Their use was still restricted to warning lights or indicators on a panel, their use was limited, so very little profit there. In the year 2000, semi conductors began to improve and experiments made to increase the current to a higher level, these LEDs could produce a decent light to power a new range of Torches( Flash lights) etc. These began to appear in the millions and paved the way for other uses eg, TV and film lighting and emergency lighting etc. The “Cree” bulb was invented which was a phoserous semi conductor which needed a high current to excite it but produced a powerful beam, the diode was fairly bullit proof but it needed a transformer and other components to power it. This is the week point of LEDs today, the components can fail early and then you have to throw the bulb away. Billions of resin diodes were produced bringing down the price of these bulbs so manufacturers then designed lights to take advantage of these cheap as chips light bulbs (LEDs). Most of these new lights came out of China, many were not designed for film or TV use but for the Video fraternity, the cheap end of the market but the most profitable. These are now produced by the million, everybody wants one, because they are affordable even the Professional range by ‘you know who’, are ‘badged’ Chinese made ones. Everybody is making making money, this is a good business to be in. These lamps are quick and easy to set up due to their size and weight, you don’t need “beefy men” to set these up and can pack away in a small van. The types can even change the colours by reducing the current with a variable resistor built into the lamp, you can alter the RGB in the silicon semi conductor to suit your needs. These are the ones most people are buying these days.
Understanding how diodes work helps to understand how they evolved, the technology has always been there but nobody knew how to apply it. It has made a lot of people wealthy and will continue to do so, is it what people need, probably not but what is the alternative, Mole Richardson will soon be using LEDs in their lamps soon. Film making will be forced to adapt to the new ways.
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