As I mentioned before we are currently developing an application which runs on a dedicated android-device. When implementing the auto-start function I noticed that android enters a screen-locked state after booting. This snippet disables the lock.
KeyguardManager keyguardManager = (KeyguardManager)getSystemService(Activity.KEYGUARD_SERVICE);
KeyguardLock lock = keyguardManager.newKeyguardLock(KEYGUARD_SERVICE);