It was in early January that the incident took place.
The man broke into the woman's home and tried to have intercourse through threats and violence.
According to the verdict, the man must, among other things, have held a knife aimed at her.
The woman's son and her granddaughter came home while the man was still in the apartment.
The evidence included interrogation of witnesses and photographs from the apartment.
The man denies the crime and says that it was the woman who wanted sex.
The verdict states that the woman is old, fragile and almost completely blind.
"It is difficult to imagine that she would want or be able to overpower and make sexual advances against a 30-year-old stranger," the district court writes in the judgment.
The man is now sentenced by Umeå District Court to one year and six months in prison.
The man must also pay damages of SEK 62,000 to the woman.