An English gentleman (Joseph Swan) patented a similar light bulb in England a few months before Edison and other light bulb development considerably predated that. In fact, on October 8, 1883 the US Patent Office ruled that Edison’s US Patent was invalid due to prior art by William Sawyer. To summarize the story so far, the “light bulb” idea was not Edison’s, successful development took considerable resources, and Edison’s patent was worthless well before it had a chance to expire.Edison, Sawyer, and Swan were not the only ones pursuing improvements on the light bulb idea. But even with Edison eventually winning the U.S. patent, it didn't do him a whole lot of good:
But Edison’s light bulb must have been a smashing success right? After all, it cost him over $10,000–in 1879 dollars when cheap labor cost 7 cents an hour–and everybody must have wanted electric light bulbs right? Some $200,000 plus later the light bulb was commercialized and 3,144 light bulbs had been sold to 203 customers by sometime in 1882. By 1889, 10 years after the patent, there were only 710 customers. The problem was that electricity and its support infrastructure cost too much and, of course, had to be installed. Ten more years later, after electricity costs had come down, there were 3 million customers and all the basic light bulb patents had expired. In fact it took 46 years for electric lighting to reach just 25% of the US population.We love to beat a dead horse here at Right to Create, and our current system of ignoring the independent invention defense is certainly a rotten, stinking corpse.
Seven years, and more than $100,000 in litigation expenses after Edison’s patent was invalidated by the US Patent Office, on October 6, 1889, a judge ruled that the electric light improvement claim for "a filament of carbon of high resistance" was valid. Unfortunately further research exposed in A Streak of Luck by Robert Conot (1979), also shows that Edison and his attorneys hid significant information from the judge. They cut out the October 7-21, 1879 section of a notebook that the judge might have determined showed that they were simply extending Sawyer’s (or Swan’s) work with carbon "burners" or "rods" in an evacuated glass bulb.
The reality probably is that all Edison and his team did was change their terminology to "filament" and there is a high probability they got that from a presentation Mr. Swan made in the US after filing for his patent in England. In fact, Edison and his team did not find a commercially workable filament (bamboo) until more than 6 months after Edison filed the patent application. The weak and short lived (40-150 hours) carbon filament was laid to rest for good by the coming of the tungsten filament in 1906.
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