Family Entertainment Centers Inc., which operates Chuck E. Cheese's Pizza Time Theatres under franchise, announced that the company will open at least 60 G. D. Ritzy's Luxury Grill and Ice Cream restaurants in the Washington and Baltimore areas in the next six years.

Patrick A. Hopf, chairman and president of Family Entertainment Centers, said the company has reached an agreement in principle to purchase exclusive franchise rights to the restaurants and expects to open at least 23 such restaurants in Pennsylvania, in addition to the outlets in this area. The move is a major diversification for the company, which has its headquarters in Rockville.

The company operates 18 Chuck E. Cheese units in the Washington area under a franchise from Pizza Time Theatre of Sunnyvale, Calif.

Hopf said that he expects a final agreement to be reached in about 30 days. He also said that the company will open about five more Chuck E. Cheese units and two of the G. D. Ritzy restaurants by the end of 1983.

The announcement came at the same time Hopf was reporting earnings and sales. Sales have been disappointing, the company said. Even so, "we expect 1983 to be a good year," said Hopf. For the 13 weeks ended April 3, the company earned approximately $275,000 on sales of $5.3 million.