A Correction - Colour Depths of Modern e-IPS and cPVA Panels

[Thresh]

Ουσιαστικά ο λόγος για τον οποίο υπάρχει τέτοια διαφορά τιμής ανάμεσα στα H-IPS και σε μερικά E-IPS panel Monitors...

 

http://www.tftcentral.co.uk/news_archive/23.htm#colour_depths

 

 

We have recently discovered some more detailed information about the operation of the latest generations of IPS and PVA panels from LG.Display and Samsung respectively. I wanted to make a brief mention of the information here for clarity and to avoid confusion.

 

e-IPS - These new panels have been in production for some time, with modules available in 21.5, 22, 23 and 24" sizes and widely used in modern popular displays. Originally the information available about all these modules suggested that they were true 8-bit displays, supporting 16.7m colours. This was in keeping with traditional S-IPS panels as well. LG.Display's website only lists basic information summaries against their panels, and in fact nowadays doesn't even give the full part number. While the e-IPS modules are not listed here any more, they were originally listed as "8-bit" in the brief description and so reviews of models using these panels will refer to them as 8-bit displays. We too fell into that trap based on the information available at the time. However, recently we have been able to study the detailed LG.Display product datasheets which describe the inner workings of the panels for OEM's looking to use them. We discovered that some of the e-IPS panels are in fact using 6-bit colour depth, with Advanced Frame Rate Control (A-FRC) to produce the 16.7m colours, similar to how TN Film panels operate. This doesn't apply to all the e-IPS panels as you can see from the table below. I would expect this was a cost saving measure and at the end of the day, most regular users would never know or care.

 

EDIT: Apologies, we had wrongly merged the NEC series screens into the same category as the Dell U2311H, when in fact they use a slightly different panel part (SLA1 instead of SLC1). Thanks to user feedback, this has been updated in the above.

 

Now this isn't really a massive issue in our opinion. Yes, it might make a difference to some people who are looking for a true 8-bit compatible display, but most regular users would never even notice any difference with panels using modern FRC mechanisms. In fact we saw no adverse affects of this technology when we reviewed some of these monitors either and neither did other review sites. I'm only bringing it up to offer full transparency and for those interested in the detail. I have also updated the relevant reviews with mention of this change.

 

Also, keep in mind that the same situation can be found when you consider the modern "10-bit" panels. LG.Display again list their new 24, 27 and 30" modules as being 10-bit, and you will see highly regarded manufacturers like NEC and Eizo (and others) refer to their displays as 10-bit. In fact, with the exception of a couple of very expensive models, these screens are all using panels which feature an 8-bit+AFRC colour depth, so again, not a true 10-bit! Some models don't even use an 8-bit+AFRC panel, but carry out the FRC at a hardware LUT level instead of on the panel side. So there's no difference there really.

 

 

 

cPVA - Although information is a little more scarce for these modern PVA panels, I thought I'd make a quick note about them here as well. Being PVA, it is probably assumed that these are true 8-bit panels as well. Samsung don't actually list the colour depth on their Samsung Panel website so thankfully that is not causing confusion. Again, studying the detailed datasheet for the known cPVA parts (23" LTM230HP01) confirms that the panel is actually 6-bit + Hi-FRC. We do not know the other Samsung cPVA panel parts at present, but suspect the 20" module is the same situation.