A Delaware judge has given Cogent Inc. the go-ahead to pursue a $943 million tender offer from 3M Co. that expires Thursday. The $10.50 a share bid had been threatened by a larger offer from NEC Corp.

Shareholders of Pasadena maker of fingerprint-identification systems have until 9 p.m., or midnight Eastern time on Thursday to accept 3M’s $10.50-a-share offer. Founder and Chief Executive Ming Hsieh already has tendered his nearly 39 percent stake in the company.

Cogent said Wednesday that a Delaware Chancery Court judge rejected a challenge by shareholders who wanted the company to pursue NEC’s $12-a-share bid. Cogent argued that the NEC bid was non-binding and likely to pose more serious antitrust issues.

Chancery Judge Parsons sided with Cogent’s argument that NEC’s offer wasn’t firm enough. Parsons also ruled that plaintiffs “had not shown a reasonable probability of success on the merits of any of their claims.”

All regulatory hurdles for the 3M deal have been cleared, Cogent said, allowing the acquisition to be completed once sufficient shares have been tendered. “We are pleased with the judge’s ruling,” Hsieh said in a statement, “The (board) continues to strongly endorse the proposed acquisition of the company by 3M.”

Cogent shares closed down 16 cents, or 1.5 percent, to $10.57 on the Nasdaq.