17ms Screen refresh rate tech question

[adge666]

Hi I'm new around here, I hope you can help, this is for my dissertation.

If I send a timed image to a 60Hz LCD monitor, say 15ms, will it display for the full screen refresh of 17ms? What would happen if I send a 25ms timed image? Will it display for 2 x 17ms = 34ms? I also read somewhere that even if I send a 17ms image, it may be displayed up to 1.5 screen refreshes. What I really need to know how long a 25ms image is likely to remain on the screen. Hope you can help! I'm writing about subliminal exposures by the way.

Thanks Adge

 

[pcy]

Hi,


I'm unsure what you mean by a "timed image" in this context, but I suspect it does not matter.


AFAIK the screen collects a complete image and writes the whole of it to the display matrix and leaves it ther for teh refresh period while it organizes the next image.




Peter

 

[biostud]

I guess it depends whether vertical sync is on or off. If it is on it will show the image in multiplications of 17ms if it's off I guess the image will tear, but I'm not sure about it.

 

[GaryJohnson]

What I really need to know how long a 25ms image is likely to remain on the screen.

If vertical sync is on, the time it's on screen would be a multiple of the refresh time. So with 16ms refreshes (60Hz), either 16ms or 32ms. Which it is depends on when the last refresh occured. If a refresh just happened before you displayed the image, then the image won't be displayed till the next refresh even though the time for it to be displayed is already counting down.

If vertical sync is off, you can have partial screen refreshes. (aka: tearing) The top 20% of the image might make it into the first refresh, 100% image in the next, and the bottom 25% in the third.

On average a 25ms image will be displayed 25ms. Not always a specific amount of time, but on average the amount of time it's supposed to be displayed is how long it will be displayed.