Shaver on Edison's light bulb: "Scientifically speaking, his team’s discoveries were neither the first, nor the most important."
Lea Shaver's article in 69 Wash & Lee L. Rev. 1891 was not her first commentary on Edison and the light bulb.
For example, one has the 2010 post New light from an old source, which includes the text:
Contrary to popular wisdom, however, Edison’s team was merely one of dozens that co-invented electric light bulb.
Scientifically speaking, his team’s discoveries were neither the first, nor the most important.
What Edison did better than all the other inventors took place not in the laboratory, but in the law office.
His lawyers pursued, obtained, asserted, and litigated key patents on light bulb technology in order to run competing bulb manufacturers out of business or buy them (...)
It was at this point, in 1879, that Edison filed for his first patent on “an improvement in Electric Lamps and in the method of manufacturing the same.” The improvement Edison claimed was the use of a certain type of filament inside the bulb.
Edison then leveraged his monopoly on bulbs to corner the market in electricity service as well. Over a century later, General Electric is the longest-running member of the Dow Jones industrial average.
For example, Thomas Swan had light bulb patents of his own, the first predating Edison’s by 19 years. He had even been granted a patent in England claiming the same discovery Edison’s team claimed to have made.
But he was unable to retain the legal upper hand. Even though it was never legally established that Swan’s bulbs infringed on Edison’s patents, the shadow of IP law made it too risky for Swan to continue competing. The two companies merged.
In the process, competition in the light bulb market – and therefore the race to roll out improvements and cut prices – was severely curtailed. And a half century would pass before ordinary Americans could afford electric lights.
In theory, patents promote innovation by providing greater incentives to invention. But it can also work the other way, by erecting legal barriers to follow-on innovation.
This 2010 post suggest a link to an earlier post at the blog of the Information Society Project at Yale Law School, , which yields
Page not found
The requested page could not be found.
and to a speech, which also yields
Page not found
The requested page could not be found.
and to a law review article [my article from the Wisconsin Law Review ] , which yields
Not Found
The requested URL /lawreview/ was not found on this server.
Apache/2.4.7 (Ubuntu) Server at hosted.law.wisc.edu Port 80
although the final link [http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1354788 ] does yield a result.
Footnote 8 of 69 Wash & Lee L. Rev. 1891 does reference Lea Shaver, The Right to Science and Culture, 2010 Wisc. L. Rev. 121, 122-28 for the proposition: Of course, patent protection can also be challenged on ethical grounds, including notions of human rights.
**Returning to the 2012 law review article, the introduction does assert
This Article sheds light on the role that patent law played in the light bulb's emergence. The story told here is not a conventional tale of great inventors, bright ideas, and the inevitable march of scientific progress. It is a story of corporate maneuvering and high-stakes litigation, as Thomas Edison and [p. 1894] his competitors employed patents as weapons in their battle to dominate the electrical industry. Although famous for his workshop talents, Edison would be better understood as an early Bill Gates, his business success built on a keen appreciation of the power of aggressive intellectual property strategy and the frailty of antitrust law. n3
Of the patent interference:
Between 1880 and 1883, the competitors were embroiled in a hard-fought priority battle at the U.S. patent office over which team had been first to achieve a key insight. n89 The dispute went against Edison, and the issuance of the Sawyer and Man patent in 1885- along with Westinghouse's entry in the industry-set the stage for a decade of extensive and expensive litigation. n90
Keeping in mind that Edison was basically forced out of GE by J.P. Morgan, the following text is curious:
By 1897, General Electric was the undisputed leader, and Westinghouse was its only serious rival. n152 The two companies agreed to a truce in the form of patent cross-licensing and product pricing agreements. n153 Smaller competitors were invited to join [*1931] the Incandescent Lamp Manufacturers Association, organized by General Electric. These members agreed to divide up the markets and avoid price competition. n154 The result was that G.E. sold half of the bulbs in the U.S. market, and the smaller companies divided the other half. n155 These smaller companies, dependent on G.E. patent licenses for their existence, put no downward pressure on prices and were discouraged from contributing their full potential to next-generation innovation. n156 In Bright's words: "They gave only the appearance of competition." n157 Through incorporation, patent litigation, licensing deals, and eventually purchases of stock, by 1910, G.E. controlled 97% of the market. n158 Only then could Edison finally rest, his empire secure.
In 1910, Edison had no light bulb empire.
The 2012 law review article does not seem to re-visit the 2010 text:
Scientifically speaking, his team’s discoveries were neither the first, nor the most important.
as to whose discoveries were the most important. Shaver does mention the most important patent [But in U.S. litigation one of Edison's many patents on the light bulb would ultimately play the most important role. Issued on January 27, 1880, U.S. Patent No. 223,898 ('898 Patent) recognized Thomas Alva Edison's "improvement in electric lamps," including a claim on "[a]n electric lamp for giving light by incandescence, consisting of a filament of carbon of high resistance, made as described, and secured to metallic wires, as set forth." n145 ]
**In passing, footnotes 81, 88 and 89 relating to the patent interference:
n81 See Charles Bazerman, The Languages of Edison's Light 247 (1999) ("[I]n the 15 years before Edison was granted his first patent for incandescent light, 31 patents had already been granted in that area . . . ." (citing Robert E. Conot, A Streak of Luck 214 (1979))).
n88 See generally Bazerman, supra note 81, at 247-49 (describing Edison's practice of resolving conflicting patent claims over the incandescent light by combining forces with the businesses holding competing patents, but noting that this was not successful universally, and the Sawyer Man competition was particularly vexing).
n89 See id. at 248-57 (detailing the patent interference proceedings and later litigation between the Edison and Sawyer-Man teams).
The interference related to Sawyer-Man US 317676 with claims:
We claim as our joint invention-
1. An incandescing conductor for an electric lamp, of carbonized fibrous or textile material and of an arch or horseshoe shape, substantially as hereinbefore set forth.
2. The combination, substantially as hereinbefore set forth, of an electric circuit and an incandescing conductor of carbonized fibrous material, included in and forming part of said circuit, and atransparent hermetically-sealed chamber in which the conductor is inclosed.
3. The incandescing conductor for an electric lamp, formed of carbonized paper, substantially as described.
4. An incandescin electric lamp consisting of the following elements in combination first, an illuminating-chamber made whollyof glass hermetically sealed. and out of which all carbon'consuming gas has been exhausted or driven; second, an electric-circuit conductor passing through the glass wall of said chamber and hermetically sealed therein, as described; third, an illuminating conductor in said circuit, and forming part thereof within said chamber, consisting of carbon made from a fibrous or textile material, having the form of an arch or loop, substantially as described, for the purpose specified.
In testimony whereof we have hereunto subscribed our names this 8th day of January, 1880.
Note this was filed AFTER Edison's application leading to 223,898.
Note also that interferences are about PRIORITY not about validity, as we see in the recent order in the CRISPR case and as was evident in the case of the Sawyer-Man patent at issue in the 1880-1890 time period.
Specifically, as to the fate of the Sawyer-Man patent that prevailed in the interference, from Kevin T. Richards, EXPERIMENTATION AND PATENT VALIDITY: RESTORING THE SUPREME COURT'S INCANDESCENT LAMP PATENT PRECEDENT, 101 Va. L. Rev. 1545 (2015) :
Early incandescent lamps did not use thin filaments, relying [p. 1550] instead on a thick incandescent conductor. n38 [See U.S. Patent No. 317,676 fig.3 (filed Jan. 9, 1880). ] Edison's main contribution to incandescent lighting was the discovery that a thin, high-resistance filament provided better light than the thick, low-resistance burner employed by researchers like Sawyer and Man. n39
Research centered on finding a material for the incandescent conductor that was not quickly consumed by the current passing through it. n40 Before 1880, hard mineral carbons seemed the most promising. n41 Those carbons burned slowly in open air, n42 but disintegrated quickly when a current passed through them. n43 Sawyer and Man claimed that they discovered that incandescent lamps could use carbonized fibrous or textile material as opposed to hard mineral carbon. n44 Edison argued he had made that discovery. n45
Sawyer and Man's narrowest claim in their patent was to an "incandescing conductor for an electric lamp, formed of carbonized paper." n46 [U.S. Patent No. 317,676 claim 3 (filed Jan. 9, 1880). ] Later, the Supreme Court would recognize that the paper claim was likely valid. n47 However, that claim would have been commercially worthless - few, if any, commercially successful lamps used a carbonized paper incandescent conductor. n48 To capture Edison's commercially successful lamp within the scope of their claims, Sawyer and Man had to rely on their broader claim to an "incandescing conductor for an electric lamp, of carbonized fibrous or textile material and of an arch or horseshoe shape." n49 If Sawyer and Man's broader claim was valid, they could control the entire electrical lighting industry - approximately twenty-four million bulbs per year. n50 At the time, there were no successful alternatives [*1551] to carbonized fibrous material incandescent conductors. n51 The outcome of the case, then, would effectively determine who controlled the electric lighting industry in the United States.
C. The Case
Perhaps because of the case's importance, the Supreme Court itself re-captioned the case as The Incandescent Lamp Patent. n52 In the court below, the case was captioned Consolidated Electric Light Co. v. McKeesport Light Co. n53 That caption tended to obscure the real parties in interest. Consolidated Electric Company, the plaintiff suing on the basis of the broad Sawyer and Man patent, was a subsidiary owned by George Westinghouse. n54 The McKeesport Company, the nominal defendant, really represented Edison's interest. n55 McKeesport used light bulbs from Edison Electric, and Edison agreed to indemnify McKeesport in litigation. n56
This case was the culmination of fifteen years of litigation between Edison and Westinghouse. n57 At the U.S. Patent Office, Edison attempted to claim that he had invented a lamp using fibrous vegetable material - the very thing that he later argued it was not proper to patent in Incandescent Lamp. Once litigation began, Edison attempted to delay Sawyer and Man's patent for as long as possible. n58 As will be explained later, this delay strengthened Edison's case at the Supreme Court.
Justice Bradley, a Supreme Court Justice riding circuit, decided the Western District of Pennsylvania case that led to the Incandescent Lamp decision. n59 However, Bradley did not decide the case on enablement grounds. Instead, Bradley found that the prior art invalidated the patent - that what Sawyer and Man had done was not new, or even if it [p. 1552] was new, that there was no "invention" because of what previous inventors had done before. n60
[p. 1554]
So the Court laid down a clear test for determining whether the description was sufficient: "If the description [of the invention] be so vague and uncertain that no one can tell, except by independent experiments, how to construct the patented device, the patent is void." n77
B. Analysis
In fashioning a test that obviated the need for experimentation, the Court attempted to reconcile what Sawyer and Man claimed in their patent with what they actually invented. After Incandescent Lamp, the Court allows broad claims but shows concern about preempting fields of research. n78 A patent preempting research into a certain field prevents innovation in that field for the term of the patent. Before the Court allows that preemption, it requires inventors to show that they have achieved the best result within that field. Simply recognizing that a field has promise is not an invention; invention is finding a real solution to a real problem. The Court determines whether the patent presents a real solution by asking whether the patent description answers the problem or merely makes a suggestion for others to investigate "by independent experiments." n79
Note also footnote 68, confirming that NOT all claims were invalidated [ The Court seemed to accept only the claim to carbonized paper as valid. See id. ] Edison did not infringe this claim because he did not use carbonized paper; that is why the loss of the interference was not significant.
**Note previous post on IPBiz
http://ipbiz.blogspot.com/2016/03/lea-shaver-said-central-mistake-made-by.html
**Note also, from the 2011 post -- http://spectrum.ieee.org/consumer-electronics/standards/requiem-for-the-incandescent-lightbulb :
With an effective vacuum pump available, several inventors soon produced working lamps. In August 1881, four of them—Thomas Edison and Hiram Maxim from the United States and Joseph Swan and St. George Lane Fox-Pitt from England—displayed their bulbs in Paris at the International Exposition of Electricity, which was attended by almost a million people. The lamps differed mainly in the choice of the material that was charred in a furnace to create the carbon filament. Edison began with bamboo fiber, Swan with cotton, Maxim with paper, and Fox-Pitt with grass. The Exposition Jury measured the efficiency of the various lamps, expressing that efficiency as candlepower—the light generated by a typical wax candle—per horsepower required to produce it. Edison's lamps ranked as the most efficient, giving 196 candlepower of light per horsepower applied to the generator. Maxim's gave 151, and the other two scored in between. The jury didn't consider how long each lamp lasted, and at that time it wasn't generally appreciated that the life of a filament lamp and its efficiency are interchangeable.
(...)
Before it could flourish, electric lighting had to defeat an entrenched competitor in many towns—gas. In the mid- and late 19th century, gaslight simply meant a bare gas flame, so the electric lamp, which produced no smoke, was a clear winner. But the gas industry didn't give up easily; it developed the gas mantle during the 1880s, then greatly improved it in the 1890s. This fine mesh, made mainly of thorium oxide, became incandescent when heated by a gas flame smaller than what had been used in previous generations of gas lamps. This technology also allowed the industry to change the composition of its gas so that the flames produced more heat and less light—and less smoke. The gas mantle turned out to be a cheaper source of light than the carbon filament lamp. Score round one to gas.
Starting around 1899, electricity answered the gas mantle with the metal filament, which could be operated at a hotter temperature, and therefore more efficiently, than a carbon filament.
(...)
In early tungsten lamps, the filaments sat in near vacuums, but it turned out that a little nitrogen or argon reduced the evaporation of the metal and prolonged the filament's life. The problem was that the gas also cooled the filament, making the lamp less efficient.
(...)
In 1959, General Electric (U.S.) refined the filament lamp one more time. Its researchers sealed a tungsten filament into a compact bulb containing an inert gas and a small amount of a halogen, usually iodine or bromine.
(...)
In a halogen bulb, the halogen gas combines with the minute particles of tungsten that evaporate from the filament, which in ordinary incandescent lamps are deposited mostly on the inner surface of the bulb and over time gradually dim the light output. The tungsten halide that forms moves around as a gas and then, when it nears the hot filament, breaks down, redepositing the tungsten back onto the filament and releasing the halogen to repeat the process.
For example, one has the 2010 post New light from an old source, which includes the text:
Contrary to popular wisdom, however, Edison’s team was merely one of dozens that co-invented electric light bulb.
Scientifically speaking, his team’s discoveries were neither the first, nor the most important.
What Edison did better than all the other inventors took place not in the laboratory, but in the law office.
His lawyers pursued, obtained, asserted, and litigated key patents on light bulb technology in order to run competing bulb manufacturers out of business or buy them (...)
It was at this point, in 1879, that Edison filed for his first patent on “an improvement in Electric Lamps and in the method of manufacturing the same.” The improvement Edison claimed was the use of a certain type of filament inside the bulb.
Edison then leveraged his monopoly on bulbs to corner the market in electricity service as well. Over a century later, General Electric is the longest-running member of the Dow Jones industrial average.
For example, Thomas Swan had light bulb patents of his own, the first predating Edison’s by 19 years. He had even been granted a patent in England claiming the same discovery Edison’s team claimed to have made.
But he was unable to retain the legal upper hand. Even though it was never legally established that Swan’s bulbs infringed on Edison’s patents, the shadow of IP law made it too risky for Swan to continue competing. The two companies merged.
In the process, competition in the light bulb market – and therefore the race to roll out improvements and cut prices – was severely curtailed. And a half century would pass before ordinary Americans could afford electric lights.
In theory, patents promote innovation by providing greater incentives to invention. But it can also work the other way, by erecting legal barriers to follow-on innovation.
This 2010 post suggest a link to an earlier post at the blog of the Information Society Project at Yale Law School, , which yields
Page not found
The requested page could not be found.
and to a speech, which also yields
Page not found
The requested page could not be found.
and to a law review article [my article from the Wisconsin Law Review ] , which yields
Not Found
The requested URL /lawreview/ was not found on this server.
Apache/2.4.7 (Ubuntu) Server at hosted.law.wisc.edu Port 80
although the final link [http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1354788 ] does yield a result.
Footnote 8 of 69 Wash & Lee L. Rev. 1891 does reference Lea Shaver, The Right to Science and Culture, 2010 Wisc. L. Rev. 121, 122-28 for the proposition: Of course, patent protection can also be challenged on ethical grounds, including notions of human rights.
**Returning to the 2012 law review article, the introduction does assert
This Article sheds light on the role that patent law played in the light bulb's emergence. The story told here is not a conventional tale of great inventors, bright ideas, and the inevitable march of scientific progress. It is a story of corporate maneuvering and high-stakes litigation, as Thomas Edison and [p. 1894] his competitors employed patents as weapons in their battle to dominate the electrical industry. Although famous for his workshop talents, Edison would be better understood as an early Bill Gates, his business success built on a keen appreciation of the power of aggressive intellectual property strategy and the frailty of antitrust law. n3
Of the patent interference:
Between 1880 and 1883, the competitors were embroiled in a hard-fought priority battle at the U.S. patent office over which team had been first to achieve a key insight. n89 The dispute went against Edison, and the issuance of the Sawyer and Man patent in 1885- along with Westinghouse's entry in the industry-set the stage for a decade of extensive and expensive litigation. n90
Keeping in mind that Edison was basically forced out of GE by J.P. Morgan, the following text is curious:
By 1897, General Electric was the undisputed leader, and Westinghouse was its only serious rival. n152 The two companies agreed to a truce in the form of patent cross-licensing and product pricing agreements. n153 Smaller competitors were invited to join [*1931] the Incandescent Lamp Manufacturers Association, organized by General Electric. These members agreed to divide up the markets and avoid price competition. n154 The result was that G.E. sold half of the bulbs in the U.S. market, and the smaller companies divided the other half. n155 These smaller companies, dependent on G.E. patent licenses for their existence, put no downward pressure on prices and were discouraged from contributing their full potential to next-generation innovation. n156 In Bright's words: "They gave only the appearance of competition." n157 Through incorporation, patent litigation, licensing deals, and eventually purchases of stock, by 1910, G.E. controlled 97% of the market. n158 Only then could Edison finally rest, his empire secure.
In 1910, Edison had no light bulb empire.
The 2012 law review article does not seem to re-visit the 2010 text:
Scientifically speaking, his team’s discoveries were neither the first, nor the most important.
as to whose discoveries were the most important. Shaver does mention the most important patent [But in U.S. litigation one of Edison's many patents on the light bulb would ultimately play the most important role. Issued on January 27, 1880, U.S. Patent No. 223,898 ('898 Patent) recognized Thomas Alva Edison's "improvement in electric lamps," including a claim on "[a]n electric lamp for giving light by incandescence, consisting of a filament of carbon of high resistance, made as described, and secured to metallic wires, as set forth." n145 ]
**In passing, footnotes 81, 88 and 89 relating to the patent interference:
n81 See Charles Bazerman, The Languages of Edison's Light 247 (1999) ("[I]n the 15 years before Edison was granted his first patent for incandescent light, 31 patents had already been granted in that area . . . ." (citing Robert E. Conot, A Streak of Luck 214 (1979))).
n88 See generally Bazerman, supra note 81, at 247-49 (describing Edison's practice of resolving conflicting patent claims over the incandescent light by combining forces with the businesses holding competing patents, but noting that this was not successful universally, and the Sawyer Man competition was particularly vexing).
n89 See id. at 248-57 (detailing the patent interference proceedings and later litigation between the Edison and Sawyer-Man teams).
The interference related to Sawyer-Man US 317676 with claims:
We claim as our joint invention-
1. An incandescing conductor for an electric lamp, of carbonized fibrous or textile material and of an arch or horseshoe shape, substantially as hereinbefore set forth.
2. The combination, substantially as hereinbefore set forth, of an electric circuit and an incandescing conductor of carbonized fibrous material, included in and forming part of said circuit, and atransparent hermetically-sealed chamber in which the conductor is inclosed.
3. The incandescing conductor for an electric lamp, formed of carbonized paper, substantially as described.
4. An incandescin electric lamp consisting of the following elements in combination first, an illuminating-chamber made whollyof glass hermetically sealed. and out of which all carbon'consuming gas has been exhausted or driven; second, an electric-circuit conductor passing through the glass wall of said chamber and hermetically sealed therein, as described; third, an illuminating conductor in said circuit, and forming part thereof within said chamber, consisting of carbon made from a fibrous or textile material, having the form of an arch or loop, substantially as described, for the purpose specified.
In testimony whereof we have hereunto subscribed our names this 8th day of January, 1880.
Note this was filed AFTER Edison's application leading to 223,898.
Note also that interferences are about PRIORITY not about validity, as we see in the recent order in the CRISPR case and as was evident in the case of the Sawyer-Man patent at issue in the 1880-1890 time period.
Specifically, as to the fate of the Sawyer-Man patent that prevailed in the interference, from Kevin T. Richards, EXPERIMENTATION AND PATENT VALIDITY: RESTORING THE SUPREME COURT'S INCANDESCENT LAMP PATENT PRECEDENT, 101 Va. L. Rev. 1545 (2015) :
Early incandescent lamps did not use thin filaments, relying [p. 1550] instead on a thick incandescent conductor. n38 [See U.S. Patent No. 317,676 fig.3 (filed Jan. 9, 1880). ] Edison's main contribution to incandescent lighting was the discovery that a thin, high-resistance filament provided better light than the thick, low-resistance burner employed by researchers like Sawyer and Man. n39
Research centered on finding a material for the incandescent conductor that was not quickly consumed by the current passing through it. n40 Before 1880, hard mineral carbons seemed the most promising. n41 Those carbons burned slowly in open air, n42 but disintegrated quickly when a current passed through them. n43 Sawyer and Man claimed that they discovered that incandescent lamps could use carbonized fibrous or textile material as opposed to hard mineral carbon. n44 Edison argued he had made that discovery. n45
Sawyer and Man's narrowest claim in their patent was to an "incandescing conductor for an electric lamp, formed of carbonized paper." n46 [U.S. Patent No. 317,676 claim 3 (filed Jan. 9, 1880). ] Later, the Supreme Court would recognize that the paper claim was likely valid. n47 However, that claim would have been commercially worthless - few, if any, commercially successful lamps used a carbonized paper incandescent conductor. n48 To capture Edison's commercially successful lamp within the scope of their claims, Sawyer and Man had to rely on their broader claim to an "incandescing conductor for an electric lamp, of carbonized fibrous or textile material and of an arch or horseshoe shape." n49 If Sawyer and Man's broader claim was valid, they could control the entire electrical lighting industry - approximately twenty-four million bulbs per year. n50 At the time, there were no successful alternatives [*1551] to carbonized fibrous material incandescent conductors. n51 The outcome of the case, then, would effectively determine who controlled the electric lighting industry in the United States.
C. The Case
Perhaps because of the case's importance, the Supreme Court itself re-captioned the case as The Incandescent Lamp Patent. n52 In the court below, the case was captioned Consolidated Electric Light Co. v. McKeesport Light Co. n53 That caption tended to obscure the real parties in interest. Consolidated Electric Company, the plaintiff suing on the basis of the broad Sawyer and Man patent, was a subsidiary owned by George Westinghouse. n54 The McKeesport Company, the nominal defendant, really represented Edison's interest. n55 McKeesport used light bulbs from Edison Electric, and Edison agreed to indemnify McKeesport in litigation. n56
This case was the culmination of fifteen years of litigation between Edison and Westinghouse. n57 At the U.S. Patent Office, Edison attempted to claim that he had invented a lamp using fibrous vegetable material - the very thing that he later argued it was not proper to patent in Incandescent Lamp. Once litigation began, Edison attempted to delay Sawyer and Man's patent for as long as possible. n58 As will be explained later, this delay strengthened Edison's case at the Supreme Court.
Justice Bradley, a Supreme Court Justice riding circuit, decided the Western District of Pennsylvania case that led to the Incandescent Lamp decision. n59 However, Bradley did not decide the case on enablement grounds. Instead, Bradley found that the prior art invalidated the patent - that what Sawyer and Man had done was not new, or even if it [p. 1552] was new, that there was no "invention" because of what previous inventors had done before. n60
[p. 1554]
So the Court laid down a clear test for determining whether the description was sufficient: "If the description [of the invention] be so vague and uncertain that no one can tell, except by independent experiments, how to construct the patented device, the patent is void." n77
B. Analysis
In fashioning a test that obviated the need for experimentation, the Court attempted to reconcile what Sawyer and Man claimed in their patent with what they actually invented. After Incandescent Lamp, the Court allows broad claims but shows concern about preempting fields of research. n78 A patent preempting research into a certain field prevents innovation in that field for the term of the patent. Before the Court allows that preemption, it requires inventors to show that they have achieved the best result within that field. Simply recognizing that a field has promise is not an invention; invention is finding a real solution to a real problem. The Court determines whether the patent presents a real solution by asking whether the patent description answers the problem or merely makes a suggestion for others to investigate "by independent experiments." n79
Note also footnote 68, confirming that NOT all claims were invalidated [ The Court seemed to accept only the claim to carbonized paper as valid. See id. ] Edison did not infringe this claim because he did not use carbonized paper; that is why the loss of the interference was not significant.
**Note previous post on IPBiz
http://ipbiz.blogspot.com/2016/03/lea-shaver-said-central-mistake-made-by.html
**Note also, from the 2011 post -- http://spectrum.ieee.org/consumer-electronics/standards/requiem-for-the-incandescent-lightbulb :
With an effective vacuum pump available, several inventors soon produced working lamps. In August 1881, four of them—Thomas Edison and Hiram Maxim from the United States and Joseph Swan and St. George Lane Fox-Pitt from England—displayed their bulbs in Paris at the International Exposition of Electricity, which was attended by almost a million people. The lamps differed mainly in the choice of the material that was charred in a furnace to create the carbon filament. Edison began with bamboo fiber, Swan with cotton, Maxim with paper, and Fox-Pitt with grass. The Exposition Jury measured the efficiency of the various lamps, expressing that efficiency as candlepower—the light generated by a typical wax candle—per horsepower required to produce it. Edison's lamps ranked as the most efficient, giving 196 candlepower of light per horsepower applied to the generator. Maxim's gave 151, and the other two scored in between. The jury didn't consider how long each lamp lasted, and at that time it wasn't generally appreciated that the life of a filament lamp and its efficiency are interchangeable.
(...)
Before it could flourish, electric lighting had to defeat an entrenched competitor in many towns—gas. In the mid- and late 19th century, gaslight simply meant a bare gas flame, so the electric lamp, which produced no smoke, was a clear winner. But the gas industry didn't give up easily; it developed the gas mantle during the 1880s, then greatly improved it in the 1890s. This fine mesh, made mainly of thorium oxide, became incandescent when heated by a gas flame smaller than what had been used in previous generations of gas lamps. This technology also allowed the industry to change the composition of its gas so that the flames produced more heat and less light—and less smoke. The gas mantle turned out to be a cheaper source of light than the carbon filament lamp. Score round one to gas.
Starting around 1899, electricity answered the gas mantle with the metal filament, which could be operated at a hotter temperature, and therefore more efficiently, than a carbon filament.
(...)
In early tungsten lamps, the filaments sat in near vacuums, but it turned out that a little nitrogen or argon reduced the evaporation of the metal and prolonged the filament's life. The problem was that the gas also cooled the filament, making the lamp less efficient.
(...)
In 1959, General Electric (U.S.) refined the filament lamp one more time. Its researchers sealed a tungsten filament into a compact bulb containing an inert gas and a small amount of a halogen, usually iodine or bromine.
(...)
In a halogen bulb, the halogen gas combines with the minute particles of tungsten that evaporate from the filament, which in ordinary incandescent lamps are deposited mostly on the inner surface of the bulb and over time gradually dim the light output. The tungsten halide that forms moves around as a gas and then, when it nears the hot filament, breaks down, redepositing the tungsten back onto the filament and releasing the halogen to repeat the process.
posted by Lawrence B. Ebert at 11:52 AM
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