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Does Panel Switching Affect Tech Specs?

Vincent Alzieu
Translator: Catherine Barraclough
September 1, 2010 1:47 PM
One of our readers contacted us with a question about our investigations into panel switching in TVs. It's actually a very good question and it's worth responding to in some detail. The reader in question was wondering whether the energy consumption values quoted by manufacturers would be affected by changes in panel technology. Can we still trust the manufacturer's spec? Let's take a closer look.

I have a question about this TV panel lottery you're investigating:

Doesn't using a different type of screen technology change the overall energy consumption of the TV? Given that the TV's energy consumption is generally quoted in the product spec, wouldn't manufacturers be misleading consumers if they changed the screen technology without changing the spec?

To answer this very good question let's look at a concrete example, using the Samsung 46C630 we tested a few weeks ago. This is a particularly good example, as we tested a model with an MVA panel made by AU Optronics, whereas other owners in Europe have reported owning the same TV with a Samsung PVA panel. However, the spec sheets are the same in all European countries.

Samsung LE46C630

Here are a few of the TV's main features:

  Spec announced
 Actual
Screen size
 46" 46"
Resolution 1920 x 1080 1920 x 1080
Contrast High Contrast 1990:1
Responsiveness 100 Hz  
Viewing angles 178° / 178° 1.8 / 5
Energy consumption
 170 W 147 W

The first thing to note is that Samsung NEVER gives the panel technology in its product specs. Even if we'd actually be quite pleased to see one of Samsung's very good PVA panels advertised when used in its products, panel technology is still nowhere to be found. Samsung isn't alone though, as no manufacturers give the panel technology even if, along with Samsung, Sony produces some excellent PVA panels, and LG makes its own IPS panels, etc.

In reality, manufacturers cover their backs by only quoting a 'minimum spec'.

Contrast

The first example is quite striking, but Samsung's new way of quoting contrast is perfectly truthful and is also very clever.

Whereas you'll find completely ridiculous figures like 120,000:1 on many spec sheets these days, you'll now just see 'High Contrast', 'Ultra Contrast' or 'Mega Contrast' on Samsung TVs. With this catch-all term, there's now no problem if a lab test shows contrast at over 4000:1 for a PVA panel or 2000:1 for an MVA panel, as both can be considered 'high contrast'.

Responsiveness

This time the tactics are a little different, as manufacturers do usually give a response time for TVs. The figure quoted is the lowest score obtained over a series of tests, irrespective of the fact that the highest ghosting levels can be much higher than the minimum value.

Here too, Samsung seems to distance itself the norm ... and with very good reason! Although a response time is sometimes given by manufacturers (we found '4 ms' for the 46C630), it's no longer given as standard in the 'full product spec'. Samsung, it seems, prefers to highlight the 100 Hz function that keeps pictures smooth and flowing.

NB: Until now, the best way we've found to measure the responsiveness of a screen has been to measure the average number of ghosted images trailing a moving object. A screen with an average of 0.4 ghosted images is therefore three times more responsive than one with an average of 1.2 ghosted images.

We're currently working on a new procedure for testing responsiveness. We'll outline it in greater detail at a later date.

Viewing angles

The standard manufacturers use to test viewing angles is particularly flattering for the screen. Manufacturers measure the angle up to which the picture still looks 'good', where 'good' often means 'with a contrast ratio of 5:1' (or 10:1 if they're feeling generous). However, at this level (5:1 or 10:1), the picture is far from pleasant to watch in real terms!

The angle usually given for all kinds of panel technology except TN is 178°, which effectively means manufacturers are free to use IPS, MVA, ASV or PVA panels interchangeably.

Energy consumption

The energy consumption of the 46C630 is advertised at 170 W, whereas we recorded 147 W.

It's very rare that our readings give better results than the values quoted by the manufacturer. The quoted value generally leaves manufacturers room to manoeuvre in case they need to change a component.

Why does this happen?

This is reminiscent of the days when panel switching was widespread in the industry and wasn't really a problem for manufacturers. Back in the day, pretty much NO manufacturer of monitors, TVs or screens thought there was anything wrong with using different types of panel is their various models.

Three or four years ago, manufacturers didn't see any reason why people should be bothered about finding different components in a product to those they were expecting. The reasons they gave made good sense too ...

Devices are often developed to comply with a list of specifications. A given product therefore always complies with a specific set of spec, usually defined in terms of threshold levels, for example, with a minimum level of responsiveness, a minimum contrast ratio, a maximum power consumption etc. A few years ago, manufacturers considered that as long as a product met these criteria it was worthy of sale under the given product's name. In other words, the screen panel could be changed freely, so long as it still met the criteria set out in the product's specifications. However, this also meant that two versions of a product, both compliant with the pre-defined criteria, could have certain dramatically different features.

The second problem was that the same model of TV or monitor was often available cheaper in other countries, but was made using different (cheaper) components. A product could have the same name on several different continents, but the kinds of screen glass, panel technology, etc. could be entirely different. Cheap imports from other countries then produced a toxic cocktail of stock on sale.

Are today's consumers too demanding?

 
 
Times have changed and so have consumers, who now expect much more from manufacturers. While many consumers still fall for the old 'everything must go - special offer - monster discount - huge reduction - price crash - last few models' kind of offers designed to shift stock, others expect more from a product that just a low price. Many users now update their equipment regularly in constant pursuit of ever-higher quality. Plus, manufacturers' advertising has a role to play in creating this kind of consumption too, making everything that ever existed before sound out-dated and inferior quality.

However, by continually promoting the quality of their latest products compared with those of the previous generation, manufacturers also shouldn't be surprised to see consumers wanting more for their money, and becoming both more demanding and better informed about the technology on offer.

Sometimes manufacturers don't seem to realise just how knowledgeable some of their consumers actually are. After having recently spoken to several manufacturers on the subject, it seems that many of them don't imagine for a second that consumers have even heard of 'panel technology', let alone the actual panel types such as TN, IPS, MVA and PVA. Manufacturers are often convinced that only a few geeky engineers actually understand this type of thing, and that most consumers don't really care about it. What's more, they're even less convinced that any of you have ever heard of panel manufacturers like AU Optronics (AUO), CMO etc.

> TV Panel Switching: Findings from 2010, Hopes for 2011 : See all news

> Buyer's Guides: Our Pick of The Best Products
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