Could BFI be done using a dedicated overlay?

[xthomas]

What I think of is to use some transparent panel over the display, which shifts between transparent state and black state, it must be fast, it must be durable, it must be capable of many cycles, it must be very transparent, and it must be possible to time it strictly.

The most obvious would be a transparent Liquid Crystal display, but I don't know if the technology is really there.

The usage would be to insert black frames on LCD instead of doing backlight strobing.

 

[sharknice]

That's what active 3D glasses did. If it was on the actual display there aren't any advantages over strobing the backlight, only disadvantages.

 

[NattyKathy]

I think the main hurdle would be how to synchronize the bfi panel to the image panel. The old active 3D glasses relied on genlock either through a physical port on the GPU or an IR transmitter hooked into the NV display driver and IIRC had to be used with specific monitors of known latency.

For this idea, one would have to create their own genlock either thru software or hardware. Duplicate and phase-shift the frame presentations by 180* and you have a 2×(refresh rate) signal to drive a transistor to latch the BFI LCD on and off for half of each frame.

Getting the synchronization just right is crucial. People have tried software versions of this idea using various overlays and it easily turns into a flickering nightmare. The same risk is there with a hardware implementation.

Then there's the image quality ramifications... Having a second panel, even if very thin, over the image panel is never great for IQ.

So yeah, definitely possible. But there's a lot of challenges with the idea.