In 2003, DoCoMo introduced a mobile phone with a 3D display from Sharp. After selling about 2.8 million of them, they were discontinued in 2004 with no follow-on 3D product. No cell phone has had a 3D display since then. Interest in 3D for mobile phones and other portable devices has not gone away, however, it has just gone back to the research labs. Now it appears as if 3D may emerge from the labs again as a more viable product.

Matt Brennesholtz
Insight Media Analyst

On July 18th (i.e. today) DoCoMo posted on its web site a white paper on a new 3D display technology for mobile phones, which would presumably be suitable for other portable devices as well. (http://www.nttdocomo.com/technologies/future/3d/index.html) This posting is in the DoCoMo "Future Technologies" section of the website and is not a product announcement, but it does indicate that the idea of a 3D mobile phone has not lost its hold at DoCoMo.

This display technology is designed to work in the landscape mode when the mobile phone is held sideways. It is a lenticular array over a high-resolution LCD display. This produces autostereoscopic 3D, viewable without special glasses. Autostereoscopic displays have a problem: they have a very limited "sweet spot" for the viewer. If your eyes are in this few degree wide sweet spot, you see the 3D image. If you are out of the sweet spot, however, the image quality is poor and the image may even be unviewable.

The twist on the new display is head tracking. If your eyes aren’t in the sweet spot, no problem. A camera in the mobile phone finds out where your eyes are and moves the sweet spot to match. According to the DoCoMo website, this is done by remapping the video on the high-resolution display, not physically moving the lenticular array like some previous head-tracked systems. This expands the sweet spot from a few degrees to +/-30 degrees horizontally and +/-15 degrees vertically.

DoCoMo isn’t the only company working on 3D mobile phones. Samsung has announced a plan to sell a few hundred thousand 3D mobile phones at a premium over conventional phones. (See the July issue of Mobile Display Report for details) Samsung uses a switchable parallax barrier in its system, an alternative autostereoscopic technology to the lenticular arrays used by DoCoMo and most others. NEC presented a paper on another technology at the SPIE Electronic Imaging conference in January, one also based on a lenticular array. NEC emphasized that, unlike many autostereoscopic displays, the 2D image quality did not suffer because of the 3D, and the display could easily show Asian type fonts. While technical details are sketchy on the DoCoMo site, they do comment that when the mobile phone is used in the normal portrait mode the lenticular array acts as a diffuser and increases the viewing angle. From the description on the website, Insight Media believes the DoCoMo display should also have good 2D image quality.

One very good thing about the NEC paper was the inclusion of a market study that showed that consumers were interested in 3D mobile phone displays, at least young Japanese consumers. According to the study over half of the respondents were interested in 3D photo-mail and 3D movies on their mobile phones, and about 42% were interested in 3D games. One must never forget, the way DoCoMo did in 2003, that only about 18% of the revenue in the mobile phone business is hardware sales. The other 82% is from services. If the service providers don’t see incremental revenue in their service business from 3D mobile phones, they don’t sell 3D mobile phones in their stores. DoCoMo and NEC seem to recognize this fact, but it is not clear from their public announcements this is well understood at Samsung.

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