And she affirmed her decision to apply a broader, 2007 version of the state child-endangerment statute to Lynn rather than the one in effect from 1992 to 2004, when he was secretary for clergy.
Lynn, 62, was found guilty last June of child endangerment.
Although he was not accused of molesting children, his job as secretary required him to investigation allegations against priests and recommend action to the archbishop.
The child-endangerment count involved a priest with a history of preying on children whom Lynn allowed to live in a Northeast Philadelphia rectory, where he again molested an altar boy.
Lynn's attorneys argued that the child-endangerment statute in effect when he was secretary required direct supervision of a child.
"He was charged with endangering the welfare of a child he never knew existed," argued defense attorney Thomas A. Bergstrom.
On July 24, Sarmina sentenced Lynn to three to six years in prison. Lynn is in Waymart Prison in Northeast Pennsylvania.
Jeffrey Lindy, who represented Lynn before the county investigating grand jury and at trial, said he continues to believe Sarmina applied the wrong child-endangerment statute.
"The old district attorney, Lynne Abraham, said it did not apply," Lindy said. "We have a new D.A. who has a more aggressive view of the law. That's the D.A.'s job. It's the judge's job to say, 'No, you got that wrong.' "
Bergstrom declined to comment on Sarmina's opinion until after Friday, when he is to file a formal response in Superior Court.
Tasha Jamerson, spokeswoman for District Attorney Seth Williams, said prosecutors had no comment.
Sarmina's opinion was first reported this week by the Legal Intelligencer.
One of the church's main appeal issues was Sarmina's decision to let prosecutors use the 20 case files from the church's "Secret Archives."
The 20 priests were not on trial with Lynn and were never criminally charged. Instead, prosecutors argued that the evidence was vital to prove that the church had a long-standing practice of dealing with child sex-abuse allegations by moving accused priests to a different parish.
Lynn, prosecutors maintained, was following a pattern of conduct that officials condoned for decades.
Defense attorneys argued that admitting 20 files filled with salacious and shocking evidence of priests abusing children would prejudice the jury against Lynn.
Sarmina, however, said she was convinced the evidence's value outweighed any prejudicial impact: "It was the only way to provide a glimpse into what [Lynn] knew and intended."
Sarmina wrote that the Secret Archives illustrated Lynn's on-the-job training for handling child sex-abuse allegations.
"It was then incumbent upon [Lynn] to decide whether to perpetuate the practices in place, or to instead take measures that protected children," wrote Sarmina, who has been on the bench since 1998.
Sarmina wrote that the fact that the jury acquitted Lynn of two other charges against him shows the jury was not prejudiced by the historical files.
Sarmina also defended her evidentiary rulings during the 11-week trial and dismissed defense complaints that Assistant District Attorney Patrick Blessington prejudiced the jury with improper comments during his closing argument.
Sarmina wrote that she instructed the jury that the lawyers' arguments were not evidence: "This court's strenuous emphasis on the proper way to reach a decision effectively curtailed any prejudice that might have formed in the jury's mind as a result of the prosecutor's statement. Therefore, this claim is without merit."
Contact Joseph A. Slobodzian at 215-854-2985, email@example.com, or @joeslobo on Twitter.