Waltham Mr. Robert L. Dion, Sr. of Waltham died Thursday, April 7, 2005 at Lexington Health Care Center. He was 84. Born in Waltham, a son of the late Emile and Florence (Roberts) Dion, he was a lifelong resident. Until his retirement in 1982, Mr. Dion worked as and optics technician for the Raytheon Company and for the Thermo-Electron Company in Waltham. During World War II he served with the U.S. Army. Mr. Dion was a longtime parishioner at Our Ladys Church in Waltham had been a member of the Loyal Order of Moose, Lodge No. 1018 in Waltham. He leaves his wife of 56 years, Celia M. (DeMichele) Dion; his children, Maureen Dion-Perry of Camino, CA, Robert L. Dion, Jr. of Waltham and Carol Dion-Lees of Dracut; three grandchildren, Alison Dion-Perry and Jillian and Lauryn Lees; three brothers, Roland Dion and Alfred Dion both of Waltham and Eli Dion of Florida and many nieces and nephews including Debra Gildart of Waltham. He was also a brother of the late William Dion and Marie Boisvert. Relatives and friends are invited to attend the Funeral at 9 a.m. Monday from The Joyce Funeral Home, 245 Main Street (Rte. 20), Waltham followed by a Funeral Mass in Our Lady Comforter of the Afflicted Church, 880 Trapelo Road, Waltham at 10 a.m. Burial will be in Mount Feake Cemetery, Waltham. Visiting hours are Sunday from 2 to 4 and 7 to 9 p.m. Memorial donations may be made to Our Ladys Church, 880 Trapelo Road, Waltham, MA 02452.