Sorry, I don't know where.
Despite being one of the coolest features of the Panasonics, allowing one to project giant images yet still not see the raw LCD grid or experience the dreaded SDE ["screen door effect"] they are amazingly silent about the details of SmoothScreen and the few times I have seen them talk about it in ads the copy writers actually get it wrong in describing how it works!
Here is a simplistic description from that site cine4home
Google language translation:
"15. Screen Door / Screen Effect
The screen door effect concerns nowadays predominantly only digital projectors LCD genus.
It describes the unwanted, black distance between the individual image pixels. If you sit too close to the screen, or has good eyes, affects the entire image as if behind a "screen door". At the same time the maximum brightness and the contrast by the dark strips is impaired. Thus, the smaller the distance between the pixels, the better the result. is measured, the proportion of the distances by the so-called "fill rate". It describes the area ratio of the actual pixels in the total image. A fill rate of 70% for example means that only 70% of the image pixels are illuminated, while 30% of black lines "covered" is.
D-ILA projectors achieve a fill factor of 93%, DLP projectors and 88% conventional LCD projectors only 60%, since the conductor tracks are in the light path.
Newer LCD models have special blur functions to increase the fill rate and reduce the screen door effect. An example is the PT-AE300 with Screen Smooth function.
In PlasmaTVs the problem of fly screen does not appear. As with normal televisions, the picture is here too small in relation to the viewing distance in order to make individual pixels, "visible"."
What they refer to, at least as translated by Google, as "fill rate" is actually called "fill factor" in English.