How to save the screen from blocking, but keep the dimming function?

I would like the android screen to lock in the application. This is not an app for the market. It is installed on a special tablet.

The only solution I found was using Power Manager and using WakeLock. That way, I can keep the screen from locking, but it also keeps the screen from dimming, while losing battery.

I would like the screen to be dim and turn off the way it always does, but it can wake up when touched and does not require the user to press the power and unlock buttons.

Is it possible? How would you do something like this?