Very strong glow from the Casio F-108. The interesting thing about this is that a model with an LED backlight has enough space behind the LCD for the Glow Tape. I expected a positive display LCD to let in more light for the Glow Tape, since this is why they are more easily readable than negative displays in low ambient light situations. But seeing it is still a revelation.
Are you aware that some LCDs (many Timexes) are positive display with ambient light, and yet negative display when lit. Backlit, that is. I wonder how they would display with your tape idea. I suspect that they would allow all the light IN to charge up the LCD, but it might be difficult to read the numbers, as it would all come out, too. Unless you wore polarized glasses? Or maybe the numbers would be brighter. Or, best case: they would look like your negative display, only brighter.
Also, OP, what kind of Glow Tape did you use, and where did you get it? Thanks again for bringing something new to the fore.