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e-IPS Matrix: Highs and Lows

The monitors I’m discussing today all share one common feature. They are based on e-IPS matrixes which is the further development of the long-existing, time-tested but, unfortunately, too expensive S-IPS technology. It is this biggest downside of S-IPS – high manufacturing cost – that LG’s new technology is meant to address while trying to keep all the benefits of S-IPS.

S-IPS benefits:

  • Excellent viewing angles both horizontally and vertically: colors look almost the same on an S-IPS panel irrespective of whether your line of sight is perpendicular to it or not.
  • Good response time: equipped with not-very-aggressive response time compensation, an S-IPS panel may have an average response time of 6 to 10 milliseconds (GtG), which is fast enough for 3D games.

S-IPS disadvantages:

  • Average contrast ratio like that of TN matrixes and inferior to PVA ones.
  • Viewed from a side, black seems to have a characteristic violet tint.
  • The shimmer effect: the anti-glare coating of older S-IPS matrixes used to shimmer. This effect has been rather effectively reduced in newer matrixes.
  • Low energy efficiency: the low transparency of an S-IPS panel calls for a powerful backlight.
  • High price.

The list of lows is longer than the list of highs, yet one benefit of S-IPS technology makes it competitive. S-IPS matrixes guarantee the lowest level of color distortions whereas the competing technologies (PVA, S-PVA, C-PVA and TN) cannot avoid the tonality of the onscreen image to depend on the user's angle of sight. For example, blue may acquire a distinct greenish hue when viewed from a side. TN matrixes also have very poor vertical viewing angles while PVA matrixes cannot distinguish between the darkest halftones (this effect can be corrected in the monitor settings at the expense of the high contrast ratio which is considered one of the benefits of PVA technology) and have a high response time. Thus, S-IPS matrixes seem to be the only choice for users interested in high color accuracy.

Unfortunately, the high price of S-IPS panels limits their use to professional and semiprofessional monitors which just cannot be cheap.

The problem of high price is going to be solved by the new generation of IPS matrixes which is called e-IPS. The new matrixes have a different pixel structure and higher transparency. The latter property helps lower the brightness of the backlight and, consequently, the cost and power consumption.

e-IPS benefits:

  • Comparable to S-IPS in terms of both horizontal and vertical viewing angles. Colors look the same irrespective of your line of sight.
  • Good response time. If used together with response time compensation, e-IPS technology suits for games.
  • The shimmer effect is almost entirely eliminated.
  • Low price that allows positioning e-IPS monitors into the middle market sector.

e-IPS disadvantages:

  • Average contrast ratio comparable to TN matrixes but inferior to PVA.
  • Contrast ratio degradation when viewed from a side: black gets lighter.

Clearly, this combination of highs and lows puts e-IPS based monitors into a very advantageous position in many users' eyes. Striking a balance between technical specs and price, such monitors are quite attractive for people who want to buy something better than typical TN-based products but do not have any special requirements or preferences and do not want to pay for the satisfaction thereof. While S-IPS based monitors are mostly about “I want to pay extra for high color accuracy”, e-IPS is rather “I want to pay a little bit more for a better image quality”. The latter translates into a larger market segment, of course.

In fact, e-IPS technology has only one serious and inherent drawback. Black gets lighter when the screen is viewed from a side. This effect boils down to contrast ratio degeneration typical of all LCD matrixes. It is just more conspicuous on black with e-IPS matrixes.

Irrespective of the matrix type, an LCD screen loses contrast when viewed from a side. White gets darker and black, lighter. While both effects are usually similar in their strength, the brightening of black is more conspicuous with e-IPS matrixes. Black transforms into dark gray on them even at a rather small deflection from the perpendicular line of sight.

It must be noted, however, that this effect doesn’t affect image quality much. It only shows up with black whereas the rest of colors are displayed by e-IPS matrixes without much tonal distortion which is typical of TN and PVA technologies. Even so, the viewing angles of e-IPS matrixes are much larger than those of TN matrixes which, besides the tonal shift, make the image look darker or lighter when viewed from above or from below.

There is only one usage scenario I can think of in which the abovementioned effect may be a problem. It is when you are going to buy a large monitor for watching movies at home, under dim ambient lighting. The brightening of black may be so conspicuous in movies with a lot of dark scenes that the corners of the screen will look somewhat brighter than its middle if you sit close to the monitor. Otherwise, this problem isn’t going to bother you much.

All in all, e-IPS is an excellent choice for people who want to have a monitor with higher color accuracy than what is offered by popular TN-based products but do not want to pay much or to compromise in other parameters for that.

That’s theory. Let’s now take a look at actual e-IPS based products manufactured by Dell.

 
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