The pending legislation has had support from Microsoft, Cisco, Intel and other big tech firms. It is designed to control excessive litigation; however, detractors claim it would benefit large corporations at the expense of startups.

Inventors and CEOs from more than a dozen companies said they object to the provision that would permit companies to challenge patents after awarded in a subsequent review process.

At a briefing Thursday, several executives said they were concerned that because the esoteric, technical details of patent law are difficult to understand, a bad bill might get through Congress.

Rep. Howard Berman (D-CA), a chief sponsor of the House bill, said he would continue to "tweak" provisions when Congress negotiates the details of a final bill.