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Technology On Samsung LE40F71BX

by Colin Tang
21 February 2007

SPVA (Super Patterned Vertical Alignment)

Viewwing angle

Although not quite 178 degrees, it is still miles ahead of the pack. Source: www.samsung.com

The latest panels from Samsung use the S-PVA technology that is also employed by Sony in their W2000 and X2000 series. Although they share the same panel, that’s where the similarities end. They are developed independently and have different backlights, internal electronics and video processing.

Samsung's patented S-PVA technology claims to deliver 40-60 percent better contrast than the best panels available today. While we normally take manufacturer’s measurements with a pinch of salt, there is no denying that in terms of contrast ratios, Samsung is with the best of them. The S-PVA technology also presents a decent black level, but, we were unhappy over the red tint in the black. It would be interesting to see if the Sony panels suffer from the same problem.

One very successful implementation of the S-PVA technology is the stellar viewing angles compared to other LCD manufacturers. This is reportedly achieved by using subdivisions inside each pixel to refract backlight over a wider are.

XWCG – CCFL Backlight

Wide color gamut
The colour range is extended but the they weren't accurate.

Samsung uses a eXtended Wide Colour Gamut – Cold Cathode Fluorescent Lamp backlight for the F71 series. With the combination of colour filters and internal processing, it is supposed to enhance the range (gamut) of colours for the TV by 138 percent from the PAL color gamut. Unfortunately, deviating from the accepted standard (in the case of HD, it’s HD 709 color gamut) always introduces colour errors. This can be seen on our previous CIE chart.

Having colours that fall on the standard triangle is important because that was how the video images were encoded (without going into too much detail). To see what the director intended, we need to decode the image to form colours with accurate coordinates on the triangle. So in this case, less is more.

Digital Natural Image Engine

This technology, which has been in development since 1996, claims to make the sharpest and clearest images possible, regardless of the profile of input signals. Five image processors and a six-times density enhancer ensure the best picture from any source. What concerns me is the lack of information on the exact picture processing that takes place. Personally I don’t mind if the picture gets `processed’ as long as it comes out the other end as director intended and not market research influenced.

It is not clear if dynamic dimming is part of the engine but clearly it is a feature best left off. Sacrificing picture stability (flicker) for a few extra points on black level is not a good trade. The Samsung panel also uses an unusual gamma distortion that skews the grayscale intensity graph for brighter pictures. This is highly objectionable to some viewers who find the images unnatural.

Update:

The first fully featured DNIe engine was introduced in 2003. Samsung has continued to optimize the features since then. It comprises of the following processes:

  • 6x density enhancer - This is the scaling algorithm used for conversion of images to the native resolution of the panel. For example, SD (576) and 720p material will need to be upconverted to be displayed on a 1080p native panel. Remember, this process does not add any more detail to the image.
  • Color optimizer - This alters the saturation and white tone of the incoming picture. Should generally be turned off if you want to see the original colours.
  • Detail optimizer - The DNIe claims to sharpen edges without introducing haloing artifacts (overshoot).
  • Contrast enhancer - It employs an S-shape transfer characteristic that gives brighter, higher contrast images.
  • Motion optimizer - DNIe examines up to 70,000 images segments on different frames to reduce loss of detail and motion smearing when subband spatial and motion adaptive temporal noise filter is applied.
  • Image optimizer - Has colour control, dynamic contrast, brightness sensor and color weakness compensation. (Frankly, I don't know what the last one does)

In my opinion, some of the above features are essential for SD programmes, given the wide range of quality out there. While I believe Samsung can still improve on some aspects of DNIe performance, they are clearly heading in the right direction. Let's hope that future models will allow some flexibility in using the different features in the DNIe engine to accommodate a wider range of tastes.

10-bit Processing

Having 10 bit processing on an 8 bit source increases tolerance for errors in digital processing. This results is less potential for posterization (colour banding) especially in darker areas of the picture with graduated tone. We predict that all LCD manufacturers will implement this sooner or later.


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