19'' comparative test and response time (page 1: 19" comparative test and response time)

Introduction

This simple 19” screen comparative took on a life of its own after a few tests. Initially we wanted to change our test procedure by introducing a real response time measurement. To do that Tektronix (to whom we are thankful) lent us a top-of-the-line numerical oscilloscope, a TDS 3054B, and a photo-sensitive probe. Here we would like to take the opportunity to thank Mr Penarguear, the Mr. “Photo-sensitive probe” of Tektronix World. Specialized in photometry measurement, he adapted one of their existing probes for us, the J1803, whose silicon photodiode is used to measure response time. The sensor precision of around 1 MHz is precise to 1 µs (0.0000001 second). This is more than enough as required precision here is to the millisecond.
The probe, oscilloscope and our picture generator allowed us to measure the “real” response time of a screen, which is from black to white, between greys etc.

Results were astounding but also disturbing. We used to say that response time was not representative as it is currently measured. We were far from thinking that results would be beyond our expectations and this leads us to conclude this figure to be strictly useless. We might as well have measured screen thickness to estimate reactivity time! And the worst thing is that manufacturers are probably unaware of this fact.

We invite you to follow the different steps that brought us to this conclusion, which weakens a screen’s claimed specifications and once more the ISO 13406-2 norm.

Three popular 19´´ LCDs + one 17" reference screen

The response time issue shouldn’t overshadow our tests of these much awaited LCDs. Results are very interesting because these monitors are equipped with new panels all with different technology.

The LG Flatron L1920B is a 19” built with a 25 ms IPS panel,

The Philips 190S5FG is the first 19” with a TN panel. Released a few months ago in a 16 ms version, the 190S5FG tested is now equipped (since September) with a 12 ms panel!

The Samsung SyncMaster 193P, a 19” PVA is equipped with a faster panel than the previous generation.

To estimate their qualities and downsides we compared them to an older but still screen of reference thanks to its excellent reactivity, the Iiyama AS4314UTG. It’s already two years old, has an unappealing body, but is still amongst the fastest for games.

Now to the tests!