| Light-emitting diodes (LEDs) were an accidental | | | | applications only. The cost of materials was an |
| discovery at first. At the beginning of the 20th | | | | issue at first and, therefore, they were used only |
| century, it was discovered that when electricity | | | | in expensive laboratory and test equipment. They |
| was applied to the semiconductor Silicon Carbide | | | | later began to be used in appliances, calculators |
| (SiC) it produced a light. This light was too dim to | | | | and watches. The advent of additional colors |
| be of any use so the research was never | | | | increased their use in displays. They could be used |
| distributed. This could have been the end for the | | | | in signs and digital display equipment. |
| LED, but it wasn't content to die out. | | | | The first LED flat panel television prototype was |
| Nearly 20 years later Russian and German | | | | produced in 1977, by James P. Mitchell. This |
| scientists revisited the idea of light produced this | | | | prototype was a red, monochromatic display. |
| way. The light was still of such poor luminance | | | | Later, in the 1990s, low-cost, efficient blue LEDs |
| that the idea nearly died again. A report published | | | | emerged moving this use along. Once a full |
| in 1936, which helped to invent the term | | | | spectrum of colors was realized in the late 1990s |
| electroluminescence, revived the research for light | | | | the flat panel LED television became a fully |
| from this source. The science of | | | | functional and popular option. |
| electroluminescence languished in obscurity for a | | | | As the LED technology advanced and the |
| while. It began to gain favor again in the 1950s | | | | luminescence increased, the uses for LEDs |
| when some British scientists started | | | | increased. LEDs began popping up in devices used |
| experimenting with it again. This led to the first | | | | to illuminate areas. Flashlights, landscape lighting, |
| infrared LED. From this technology came the first | | | | and other lighting sources became popular. |
| visible spectrum LED, in red, from Gallium | | | | Emergency lights began to use this technology. |
| Phosphide (GaP). | | | | Traffic lights were replaced with LEDs. Interior |
| This was the start of the LED revolution. From | | | | lighting and headlights in vehicles became a |
| that point each decade brought advances in the | | | | common home for these lights, as well. As the |
| technology of light-emitting diodes. The use of | | | | cost of producing the lights decreased, and the |
| different substrates brought brighter lights of | | | | availability of colors and brightness increased, the |
| different colors. The colors advanced from red to | | | | uses exploded. |
| orange and on to pale green, then yellow and on | | | | From an accidental discovery to a common |
| to a brighter green. By the 1990s the use of | | | | household name, the history of LEDs is a long one. |
| Gallium Nitride helped usher in the era of blue | | | | The early discovery and limited uses of the |
| LEDs. These blue lights became the basis for | | | | light-emitting diode did not show much promise. |
| white light. The use of fluorescent phosphors | | | | Very few early researchers would probably have |
| helped change that blue light into high intensity | | | | predicted the many, varied uses for this |
| white lights. Now LEDs can be found in almost | | | | technology. The LED certainly earned its |
| every visible color of light. | | | | prominent spot in today's society. |
| This technology has led to additional uses for the | | | | Learn about clematis macropetala and clematis |
| LED as well. Due to their low light output they | | | | paniculata at the Clematis Care site. |
| started out in indicator lights and display light | | | | |