Delving into the 3D TV Technology Dispute through Picture Quality

Hello, I’m Yoo-chul Kim and I am in charge of software and global R&D strategy in the CTO Technology Strategy Team. I’m here to have a straightforward talk from a technical standpoint about the recent 3D TV technology dispute that has become such a big issue here in Korea. As a matter of fact, newspapers, broadcasts and other stories in the media try to translate complicated technology in laymen’s terms but in the process there have been many misunderstandings. Also, because materials released from different companies only focused on highlighting the shortcomings of competitors, this was indeed frustrating for a person like me who works in a technological division. It’s actually much easier to understand the content that was posted by bloggers, and I will also try to explain as objectively as possible.

First off, let’s focus our discussion in a straightforward way on the matter of 3D TV picture quality. Of course, it will again be from a purely technical perspective.

Resolution = Number of the pixels that can be counted

There’s been a lot of controversy recently about whether FPR (Film Patterned Retarder), is Full HD or not. First, let’s define what Full HD is.

Generally Full HD or 1080p is a screen that is 1,920 pixels wide and 1,080 pixels high. This also means that the human eye should be able to count all of the 2,073,600 pixels (1,920 X 1,080). (Depending on whether it’s Progressive or Interlace, it is categorized into 1080p or 1080i, but all 3D TVs currently support 1080p.)

You can count the 2 million plus pixels on 3D TVs with the glasses on, for both SG or FPR types. (I’m sure you won’t really try counting, right?) In other words, I would like to say that it would be wrong to have a dispute about the resolution difference between SG and FPR types. Why? Because they have the same resolution.

 

Take into account the difference in viewing angle at home and in the store

When purchasing TVs, monitors or mobile phones, there are times we consider the viewing angle of the device. Most products these days allow a 180 degree viewing angle. However, the viewing angle for 3D TVs, FPR and SG types alike, are limited. So, let’s take a look at if the limitation in viewing angle actually causes problems.

Unlike monitor or mobile phones, where the screen is viewing at a relatively closer distance, most people watch TV from a farther distance. According to research recently conducted in Japan, most people watch TVs at a vertical angle of 10 degrees, and a horizontal viewing angle of 55 degrees. This is the appropriate viewing angle that is normally taken into account when developing TVs.

The reason for the limitation on vertical viewing angle is because of the character of the FPR film that prevents the light from the display to disperse depending on the horizontal pixels. Currently, the vertical viewing angle is about 13 degrees and the horizontal viewing angle is about 180 degrees. From a 2-meter distance, the vertical viewing angle translates to about 92cm and from a 3m distance the angle translates into approximately 138cm.

For SG types, the viewing angles are theoretically 90 degrees for both horizontal and vertical viewing angles. However, in reality it is affected by other limitations. The TV and glasses send back and forth sync signals, and this limits the viewing angle. Currently, the viewing angle is approximately 40 degrees for both horizontal and vertical, and when the angle becomes wider, the TV can no longer sync with the glasses.

  

Both types show brightness loss due to polarized films, and 2 polarized films doubles light loss?

People believe that FPR types are dark because they use polarized films, but in reality this is not true. Developments have been made in FPR technology, and light loss is an area that has been most improved. There may be slight brightness differences in FPR and SG types when viewing without the glasses, but the actual brightness of the TVs are the same.

I want to show you how the brightness changes when you wear 3D glasses but before we do that, let me state that both types of TVs measure 450nits (nit: measurement for determining brightness). Previous PG types showed great loss in brightness, but the current FPR types show no loss in brightness from the TV itself.

FPR types show measure 170nits when seen through glasses with a single layer of polarized film. However, SG types have 2 layers of film in the glasses, showing a higher loss of brightness, and its right image- black image- left image – black image sequence also reduces the brightness to about 65nits.

The research to increase brightness continues. The easiest method could be to increase the brightness of the display backlight in 3D viewing mode. But this can also cause the side effect of worsening flickering for SG types, so more research is needed.

  

Watching 3D TV 2D Mode

Unlike SG types, there have been claims that vertical lines can be seen in FPR type TVs in 2D viewing mode. However, the lines are not visible unless the distance is very close, and cannot be seen when viewed 1.2m away from the TV, which is the LG recommended viewing distance for 3D TVs.

  

Advice on choosing 3D TV from a person that makes 3D TVs

It seems like I’ve talked about everything that I have to say regarding the technology aspect of 3D TVs. So then, what kind of TV should you buy? Of course, I can’t make the decision for you but if it was me choosing, this is what I would say:

“Get a Flicker Free 3D TV!”

From a consumer standpoint, I think the most important thing is that your eyes should be comfortable when they watch, and you should not feel dizzy. In this dispute over 3D TVs, people have talked a lot about the weight or price of the glasses, standardization of glasses, viewing position, crosstalk, resolution, viewing angle, brightness, 2D viewing or transforming 2D to 3D, and so on. But at the end of the day, the most important thing is to be able to watch high quality 3D images comfortably.

Take your time to actually see the product in the store (of course it may be different from viewing at home), go see comparison demos and carefully compare the features and prices before making a purchase decision. If you understand everything that I’ve told you here, then you’re already way more knowledgeable than salesmen in the stores.

With 3D smartphones and 3D tablets, the 3D era has truly dawned. Do you have any idea how much more fun it is to take 3D pictures and videos with 3D smartphones and tablets, and view it on your 3D TV? I hope that you will be able to take full advantage of the fun and entertaining 3D era that has dawned.

Well, today we went through the technological differences in picture quality, and the differences that can be recognized by consumers. In the next post I’ll take you through the differences in glasses for 3D TVs. See you soon.

 

 

Writer (guest) Yoo-chul Kim
Yoo-chul Kim is in charge of software and global R&D strategies in the CTO Technology Strategy Team. He is also active as an expert in technology promotion through exhibitions, lectures and recruiting. Kim will be talking about how new technology impacts our lives. On a personal level, he is interested in games, good places to eat and comic books. He longs for the day when people can share more information more conveniently.

 

 

 

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