[vslist] Re: CVNet - Compiled answers on: Phosphor persistence and CRT refresh-rates

[Klaus Hartnegg]

On Thu, 14 Mar 2002, Per Magne Knutsen wrote:

> *** ALTERNATIVE DISPLAY TYPES ***
>
> From: Greg DeAngelis <gregd@cabernet.wustl.edu>
> 3-chip DLP projectors have essentially no persistence because they
> are totally optical, but I don't think you will find refresh rates above
> 100Hz."

> From: Peter Carras <pcarras+@pitt.edu>
> "If you do not need precise color and many levels of contrast, perhaps you could use an LCD (Liquid
> Crystal
> Display) monitor. The disadvantage is that the brightness of the pixels does not decay; they stay on until
> they are turned off.  The advantage is that, theoretically, they can be turned on and off at a very high
> rate.  For a monitor with digital inputs, it should be possible to drive the display as quickly as you
> video card can send it information.

Be warned that such display methods (usually used in video projectors)
often come with a certain amount of "intelligent" electronics that does
considerably more than in a normal crt monitor. Problem: This
"intelligence" is optimized for things like PowerPoint presentations, not
for projecting visual stimuli for scientific experiments. I noticed that
all kinds of strange things can happen, for example the device sometimes
automagically doubles the frame rate whenever it "thinks" this is a good
idea. Some projectors with analog input have great difficulties
synchronizing on a video signal that changes rapidly and has dark
background.

Klaus Hartnegg
--
Klaus Hartnegg, Uni Freiburg, AG Hirnforschung, Hansa-Strasse 9, 79104 Freiburg
hartnegg@zfn-brain.uni-freiburg.de   http://www.brain.uni-freiburg.de/~klaus/