Macbook Air - OS X Yosemite 10.10.3

With the new OS X Yosemite 10.10.3 update my Macbook Air screen stay's black for like 20 to 30 seconds, than the Apple logo appears when starting up. Before this update it wasn't like this. I could typ in my password immediately. Is something wrong with my Macbook or is something wrong with the software.

Kind Regards