As for InterDigital, and other similar patent holders, it's a question of whether the inventions are sufficiently important. Can they, for example, be used to block Nortel's?

对于InterDigital和一些相似的专利所有者来说，存在一个问题就是是否专利发明是十分重要的，例如，这些专利发明能够阻止Nortel的破产吗？

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This is true despite the fact that prior to filing a patent application a thorough search is typically performed, looking for any publication that might block a patent from issuing, and that a patent application is only filed when chances for obtaining a patent appear good.

FORBES: Keep the Current Standard for Invalidating a Patent

Some patent examiners have been at the patent office for decades, and have a vast storehouse of knowledge regarding what has previously been described in a printed publication (and thereby serves to block a patent grant).

FORBES: Keep the Current Standard for Invalidating a Patent

Amgen is trying to block Roche by suing the company for patent infringement.

FORBES: Magazine Article