Date: 9th December 2010
3D ticket box office results show consumers love 3D movies. However, 3D TV sales have disappointed. Why is this? One major difference is the 3D glasses. US theaters use polarized or passive glasses. They are light, comfortable and inexpensive. However, 3D TVs on the market use active shutter glasses which are expensive, bulky and heavy due to the internal batteries necessary to control the switching liquid crystal. I believe if it wasn’t for the glasses, 3D TVs would be doing much better as it is hard to justify $500+ in glasses costs for limited 3D content.
In a recent Nielsen survey, 45% of survey respondents indicated the glasses were not comfortable. What if the low cost, light and comfortable glasses were available with your 3D TV?
Starting in 2011, 3D LCD TVs based on film patterned retarders (FPRs) will be available. Expect these TVs from LG, Philips, Vizio and a host of Chinese brands as well with panels from LG Displays and AUO.
What may cause confusion, is that performance is better in some areas than others compared with active shutter glasses 3D. In the active shutter glass approach, time multiplexing is used where the left and right images are shown in different frames within one frame time. The shutter glasses and their switching liquid crystal are opened alternately in each left and right frame in sync with the images on the TV. In addition, in the case of LCDs, a black frame is inserted in between the left and right frames. So, 240 Hz frame rates correspond to 60Hz for each of the left, black, right and black frames. This approach requires very fast liquid crystal switching and frame rates. Because LCDs don’t switch as fast as plasma or OLEDs, they tend to show more double images or ghosting than plasma or OLEDs. Furthermore, because of the black frame insertions and the shutter glasses, significant brightness is lost. Most 450-nit 3D LCD panels are actually perceived through the glasses at less than 100 nits. More than 80% of the brightness is lost. Brightness must improve to achieve a more acceptable 3D experience.
In the spatial multiplexing approach, a film patterned retarder (FPR) is applied to the top of the screen. It corresponds to the odd and even lines of the LCD and converts light to either left or right circular polarization which are seen by the polarized glasses as left and right images producing 3D images. Unlike time multiplexing, the entire frame time can be used for generating one frame. As a result, the slower liquid crystal response rates are less likely to produce ghosting or double images. The panel supplier can also use slower refresh rates if desired. 120Hz is sufficient for FPR 3D as flicker is less of an issue and there is no black frame insertion. The FPR clearly separates the left and right images, producing a more stable image. Furthermore, brightness is significantly improved as there is no black frame insertion required. Brightness should be at least 2X higher than time multiplexing approaches.
However, the FPR sacrifices resolution for these other improvements. Every other line is used for each eye. Thus, 1920 x 540 is being observed by each eye rather than 1920 x 1080. Higher resolutions have gained significant share in the TV market, although only Blu-ray movies are shown at 1920 x 1080p. Will consumers notice the difference? Will they care?
In addition, the FPR 3D approach suffers from a lower vertical viewing angle than shutter glasses 3D due to the FPR. Will this be observed in retail? When I saw numerous FPR 3D demos at FPD International last month, I didn’t perceive this, but wasn’t looking for it in particular.
Due to the differences in resolution and viewing angle, in 2D mode, the shutter glass approach should be better as you can’t turn off the FPR in 2D mode.
In terms of cost, the FPR does cost more, but FPR panel suppliers claim that they can match conventional shutter glass panel costs. This may be because of vertical integration, lower cost approaches or reducing the refresh rate. However, if the glasses costs are factored in, the FPR 3D solution should be at least 20% less costly than shutter glasses 3D TVs. So, the total purchasing cost will be less.
The advantages of each approach are summarized in the table below. I would expect the brands offering this new approach to heavily promote its advantages, while the brands not offering this approach such as Samsung, Sony and Panasonic, may actively promote its disadvantages.
It could get even more confusing for 3D if active retarder technology which does not sacrifice resolution and maintains passive glasses use is introduced. At FPD International last month, both LG and CMI were showing prototypes with this technology which looked great. However, it should be the most expensive panel solution as it requires additional an additional liquid crystal layer and an additional pair of glass substrates. OLEDs have also been shown with this approach and plasma should be able to use it as well.
In my case, I want to experience 3D in the home, but I can’t justify the glasses prices, so I am looking forward to the passive glasses 3D solutions. One of my coworkers’ objections was until he could buy a bag of 3D glasses in the supermarket or liquor store for entertaining during the Super Bowl, Final Four, etc., he is on the sidelines. Well, don’t be surprised to see bags of 3D glasses in supermarkets for Super Bowl 2012.
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