[visionlist] CRT wrapup

Max Snodderly max.snodderly at mail.utexas.edu
Mon Feb 5 14:21:04 GMT 2007


I hope this will be my last post on this subject for a while.  

1) The best confirmed high-speed performance for a currently available
display at this time is for the ViewSonic G225fB

G225f will run 800x600 at 160Hz, in a custom 160Hz mode (Yuri Petrov).

 

2) The Samsung Syncmaster CRT 1100MB will run 120 Hz, but it has not been
tested at a higher frame rate because of limitations of the video card (Hans
Irtel).  It lists 360 MHz bandwidth so it would be worth further testing.

 

3)  Useful information on phosphor decays and their measurement from
john.kelly at seattlechildrens.org

 

"I don't want to bother you with too many details, but often you need speed
and sensitivity for really accurate measurements. That is why I have used
photomultiplier tube detectors (Hammamatsu). If you need basic measurements
I ususally use a UDT Si detector (model 265). If you are motivated, I have
heard but not confirmed you can put a resister shunt (say > = 1k Ohm) across
the leads and use a current sensitive measurement to increase their speed.

 

The CRT manufacturer's typically report decay for the P-22 red and green
phosphors as1.5 and 6.0 msec, respectively. Luminescence measured by a
photomultiplier tube decayed to 1% at 9.5 msec for red and 12.0 msec for
green (the 1/e2 time constant was 1.4 and 1.8 msec for red and green,
respectively). Phosphor decay was slow enough to obscure luminescence peaks
from two pixels when pixels were separated by less than 30 raster lines.
Here are a few references that might be of interest. Reference 4 should be
of particular interest to Max.

 

 1)      S. Sherr, Electronic Displays. John Wiley & Sons Inc.; New York,
pp. 8 - 101, 1993.

 

2)      V. Di Lollo,  A.E. Seiffert, G. Burchett, R. Rabeeh, T.A. Ruman
"Phosphor persistence of oscilloscopic displays: A comparison of four
phosphors." Spatial Vision, vol. 10, pp. 353-360, 1997.

 

3)      J.A.J. Roufs, "Dynamic properties of vision - I. Experimental
relationships between flicker and flash thresholds." Vision Research, vol.
12, pp. 261-278, 1972.

 

4)      T. Hase, T. Kano, E. Nakazawa, H. Yammamoto, "Phosphor Materials for
cathode-ray tubes." Advances in Electronics and Electron Physics, vol. 79,
pp. 271-361, 1990.

 

5)      R. Groner, M.T. Groner, P. Muller, W.F. Bischof, V. Di Lollo,  "On
the confounding effects of phosphor persistence in oscilloscopic displays."
Vision Research, vol. 33, pp. 913-917,1993.

 

6)      V. Di-Lollo, W.F. Bischof, P.U. Walther-Mueller, M.T. Groner et-al.,
"Phosphor persistence in oscilloscopic displays: Its luminance and
visibility." Vision Research, vol. 34, pp. 1619-1620, 1994.

 

7)  V. Di Lollo, W.F.Bischof, "Inverse-intensity effect in duration of
visible persistence." Psychological Bulletin, vol. 118, pp. 223-237, 1995.

 

4)  Another measurement suggestion (separately posted by Michael Bach)

 

The "BPW 21" is somewhat close to the human photopic v-lambda curve
(Siemens).

 

In this old paper "Bach M (1997) A note on luminance calibration of
raster-scan cathode ray tubes: Temporal resolution, ripple and accuracy.
Spatial Vision 10:485-489" I gave a circuit diagram incorporating that
photodiode.

 

Thanks to colleagues for sharing.

 

Max Snodderly

 

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