just bought a LG 47LD650, have the same problem. but solve by your solution. i wonder what cause it.
I know there are already a lot of posts about this, but last night I solved the issue I was having with my Playstation 3 and Samsung LNT-4061F.
My setup consists of the above mentioned products talking to each other through a Denon AVR-591. I recently purchased the Playstation 3 and did not experience the blinking problem until I tried to play Gran Turismo 5. My TV started to blink, an obvious HDCP issue between the components. I started reading online and many people said there was nothing I could do, it was the TV and there was no way to update the firmware on it. Blah, blah, blah...
This is what worked for me.
1. Power on your PS3
2. Navigate to Settings -> Display Settings -> Video Output Settings
3. Select the appropriate cable (HDMI, Component, ect...)
4. At the next screen select Custom
5. Uncheck 1080p as one of the output options and press X to accept (Your TV will blink once to see if the settings are functional)
This will leave you with 1080i, 720p and 480p (which should be grayed out depending on the cable being used).
I realize that your TV is probably 1080p (mine is also), but with HDCP handshake issues it's all about making the devices communicate is the simplest way possible. You won't see a difference with 1080i in relation to 1080p, especially when playing video games.
Good luck, I hope this helps!