Texas Instruments Inc. said it has settled its patent license dispute with three Japanese companies.

Under the terms of the settlement, Oki Electric Industry Co., Matsushita Electronics Corp. and Mitsubishi Electric Corp. are to be dismissed from a patent-infringement investigation by the International Trade Commission and

from a lawsuit filed by Texas Instruments in Federal District Court.The patents involved in the dispute include Texas Instrument's dynamic random access memory (DRAM) patents.

Following the settlements, Texas Instruments and the three Japanese companies filed joint motions with the commission to terminate the investigation under section 337 of the Tariff Act of 1930 insofar as it applies to Oki, Matsushita and Mitsubishi. The motions have been granted by Janet Saxon, chief administrative law judge. However, they are subject to a 30-day review by the commission prior to becoming final.

The patent license agreements between Texas Instruments and the three companies must receive approval from the government of Japan.

Last month, Texas Instruments announced similar settlement agreements with Sharp Corp. and Fujitsu Ltd., and on Feb. 6, 1987, with Toshiba Corp.

In return for licensing its semiconductor patents to the companies, Texas Instruments receives a license under the semiconductor patents of the companies, as well as significant royalty payments. The payments are to be made during the term of the licenses, which expires at the end of 1990.

Texas Instruments will also receive unit royalties based on the use of its U.S. DRAM patents by the three companies.

Texas Instruments filed patent-infringement lawsuits on Jan. 24, 1986, in Federal District Court in Dallas against eight Japanese and one Korean semiconductor companies. The U.S. electronics giant contended that the eight were producing semiconductor memory chips (DRAMS) and selling them in the United States without licenses under its semiconductor patents.

On Feb. 7, 1986, Texas Instruments also filed a complaint with the International Trade Commission under section 337 of the Tariff Act of 1930 regarding the importation of the chips into the United States that infringe the U.S. company's patents covering DRAM technology.

Texas Instruments asked the commission to initiate an investigation, and issue a permanent exclusion order forbidding entry into and sales within the United States of DRAMs that infringe its U.S. patents. The order also included components of those DRAMS as well as products containing them.

The commission initiated an investigation on March 11, 1986, that was extended to an 18-month time period. Hearings on the validity and infringement of the 10 patents ended eight months later.

The next phase of the investigation began Jan. 5 this year, to determine if injury was done to an efficiently operated domestic industry due to the unlicensed imports. That trial concluded last Feb. 6. The judge has until mid- May 1987 to submit her initial determination to the commission.

The commission will have until Sept. 21, 1987, to render its findings.

Insofar as the patent-infringement lawsuit is concerned, discovery procedures are under way in Dallas Federal District Court. Trial date has been set for November 1987.

The remaining Japanese companies named in the 337 action and the lawsuit are Hitachi Ltd., Hitachi America Ltd., NEC Corp. and NEC Electronics Inc.

The Korean companies are Samsung Co. and Samsung Semiconductor and Telecommunications Co.

Texas Instruments and its Japanese counterparts have been accusing each other of patent infringements for the last year or so.

On March 7, 1986, Nippon Electric Corp. filed a complaint in Tokyo District Court against Texas Instruments' wholly owned Japanese subsidiary, Texas Instruments Japan Ltd. The complaint alleged DRAM patent infringement of three of Nippon Electric's patents. Texas Instruments Japan filed a response denying infringement.

On April 7, 1986, Toshiba filed a counterclaim to Texas Instrument's patent infringement lawsuit in Dallas claiming that the U.S. firm was violating one of its U.S. patents in the United States. Toshiba amended that counterclaim on Aug. 26, 1986, to add another of its U.S. patents to the counterclaim.

These counterclaims will be dropped as part of the Toshiba agreement.

On Aug. 15, 1986, Hitachi filed a patent-infringement lawsuit against Texas Instruments in Federal District Court in Alexandria, Va., alleging that Texas Instruments is violating one of Hitachi's patents involving DRAM technology. A Texas Instruments motion was granted on Sept. 30, 1986, moving the Hitachi lawsuit from Alexandria to Dallas.

A patent-infringement lawsuit was filed by Hitachi on Aug. 28, 1986, against the Japanese subsidiary of Texas Instruments. On Oct. 16, 1986, Texas Instruments filed a complaint in Tokyo District Court against Hitachi, seeking injunctive relief and alleging that Hitachi's manufacture, use and sale of certain DRAMs infringe one of Texas Instrument's Japanese patents.

On Jan. 9, 1987, Texas Instruments said it reached settlement agreements with Sharp Corp. and Fujitsu Ltd., and on Feb. 6, 1987, with Toshiba Corp. The agreements included patent licenses between Texas Instruments and each of the Japanese companies.