MIAMI (AP) _ His face has been seen by only one of his 45 known victims in five years - a woman who convinced him she couldn't see his face without her glasses and who studied him during the rape, a knife at her throat.

From the description given by the 36-year-old victim, a police artist created a drawing that was circulated throughout Coconut Grove, South Miami and Hollywood, the areas where south Florida's ''Pillowcase Rapist'' has been active since 1981.

Authorities say half a million fliers have been printed by volunteers and distributed. They are shooting for a total of 3 million of the posters to saturate the rapist's stalking grounds.

Recently, too, police commissioned sculptor Tony Lopez to fashion a detailed clay bust of the most hunted man in south Florida history.

''Maybe now that he's been stripped of his disguises, he will realize that it won't be long before we're able to put a name with the face,'' said Metro- Dade Police Sgt. David Simmons.

Since the first reported attack on a 24-year-old secretary in May 1981, the rapist has attacked young career women, usually entering houses or apartments through unlocked doors or windows and using a knife to terrify them into submission.

In each case the attacker has sought to dominate his victims, tying them up, and sometimes using a pillowcase to blindfold them.

Police have no doubt it's the same man. Using a series of blood and semen tests, officials early on were able to identify the rapist as having type O blood with subgroupings common only to 1 percent of the population.

When he struck Friday for the 45th time, the rapist changed his usual pattern and attacked a frail, half-blind 82-year-old widow after breaking into her home. She awoke about 5:30 a.m. Friday to see the rapist standing next to her bed, a pillowcase wrapped around his head with only his eyes showing.

Following the rape, the outraged woman chased him out of the house.

''She literally tore a dish towel rack from the wall of her kitchen,'' Simmons said. ''She chased him out the back door, swinging the metal fixture at him and shouting at him to get out of her house.''

The rapist took the woman's wedding band in the attack and left a bizarre set of clues - a pair of women's red, bikini-style underwear, a pair of little girl's ruffled red nylon panties, a cream-colored women's sleeveless undershirt, a navy blue leather purse with two crumpled department store bags inside, and an unidentified item of men's clothing.

''It's speculative as to what this all means,'' said Simmons, who has been in charge of the case since its start. He said it is rare for a rapist to change his style so drastically.

''This case simply exposed another dimension of his personality,'' Simmons said.

FBI behavioral scientists say the rapist has profound doubts about his sexual adequacy and that he has lived at least part of his life with a dominant, repressive woman, perhaps a wife but more probably his mother.

He is impulsive, nervous, ill at ease in social situations. He takes care of his physique and is probably in a profession requiring some physical skills.

''He could be a lifeguard, bodybuilder, firefighter, law enforcement officer, Southern Bell employee, mail carrier, construction worker. He could be a businessman,'' Simmons said.

A task force of 41 officers has received more than 500 leads in the past two weeks and interviewed and cleared more than 50 suspects, Metro-Dade Police Commander William Johnson said Tuesday.

''We just want to identify him. That's all. Once we know who he is, then we can go after him. But until then we don't have anything,'' said Metro-Dade spokeswoman Lucy Fitts.

''He has to have friends, a wife, a girlfriend...somebody,'' she said.