Lemelson was granted more than 600 patents, making him one of the 20th century's most prolific patent grantees. Through much of his later career, Lemelson was involved in a series of
patent litigations and subsequent licensing negotiations. As a result, he was both excoriated by his legal opponents and hailed as a hero by many independent inventors. For example, Lemelson claimed he had invented the "flexible track" used in the popular "
Hot Wheels" toys manufactured by
Mattel. In the 1980s Lemelson sued for willful
patent infringement, from which he initially won a substantial judgement in a jury trial. This case was later overturned on appeal. Lemelson litigated extensively on the basis of what he termed his "
machine vision" patents, the earliest of which dates from the mid-1950s. These patents described scanning visual data from a camera, which are then stored in a computer. Combining with robotic devices and
bar coders, this technology could be used to check, manipulate, or evaluate the products moving down an
assembly line. Items or products could then be adjusted or sent on to different parts of a factory for further procedures. to negotiate licenses worth over $1.3 billion from major corporations in a variety of industries. Partially as a result of his filing a succession of
continuation applications, a number of his patents (particularly those in the field of industrial machine vision) were delayed, in some cases by several decades. The courts, in the Symbol and Cognex case discussed below, however found that Lemelson had engaged in "culpable neglect" and noted that "Lemelson patents occupied the top thirteen positions for the longest prosecutions from 1914 to 2001." However, they found no convincing evidence of inequitable conduct. Indeed, Lemelson always claimed that he followed all the rules and regulations of the United States Patent Office. In 2004, Lemelson's estate was defeated in a notable court case involving
Symbol Technologies and
Cognex Corporation, which sought (and received) a ruling that 76 claims under Lemelson's machine vision patents were unenforceable. The plaintiff companies, with the support of dozens of industry supporters, spent millions on this case. The ruling was upheld on September 9, 2005 by a three judge panel of the
U.S. Court of Appeals for the Federal Circuit under the doctrine of
laches, citing "unreasonably long […] delays in prosecution". Lemelson's estate appealed for a review by the full circuit
en banc. On November 16, 2005, the full court declined to review the case, and, citing "prejudice to the public as a whole," extended the original unenforceability ruling to
all claims under the patents in question. However, the judge also ruled that Cognex and Symbol did not demonstrate that Lemelson had "intentionally stalled" getting the patents. Lemelson himself always denied intentionally stalling the patent application process, and asserted that he attempted for many years to get companies interested in his ideas, only to be rejected by what he termed the "
not invented here" response. Under current US law (35 U.S.C. 122 and 37 C.F.R. 1.211), revised by Congress in 1999, most patent applications are published 18 months after being received and any resulting patents expire 20 years after the filing date, serving to limit surprise or
"submarine" patents. Lemelson's applications were submitted under older rules, which kept the application confidential during
patent prosecution. ==Honors==