The pair become Coyle's third and fourth signings of the summer after the arrivals of Darren Pratley and Nigel Reo-Coker.
"I know that it is a good squad so the challenge for me will be to work hard and then look to contribute," said Eagles.
"I am an attacking midfielder and I will certainly be looking to chip in with some goals."
Mears added: "I'm obviously very happy the deal has been concluded I'm really looking forward to working with a manager I've worked with before and playing in the Premier League.
"From the outside looking in, this has seemed like it is a club going in the right direction. It wasn't a difficult decision at all. I know exactly what the manager expects from his players and I'm more than ready for it."