Auto-stereoscopic displays forego the need for special viewing glasses to present true 3D. Now, 3M and Toshiba Matsushita Display have teamed up to deliver handheld, 3D, auto-stereoscopic LCDs for cell phones, mobile Internet devices, and other consumer products. 3M provides the film that is used in the construction of these backlit LCDs. The display can deliver 2D, 3D, or a mix of 2D and 3D images.
The display’s construction doesn’t require any manufacturing techniques or components other than the addition of the film. The approach is particularly appropriate for handheld devices because minor orientation changes are easy. Likewise, users can optimize the system for personal viewing. Larger displays do not have this advantage, making them harder to construct.
3D LED MAGIC
The LCD stack is similar to a typical stack with side-lighting LEDs separated by a lightpipe that distributes the light to the LCD panel above (see the figure). The difference is the additional layer in between. This is the 3M film, which has been constructed so light from one side will be directed toward one eye while light from the other side will be directed to the other eye.
One set of LEDs is turned on at a time. The image on the LCD is synchronized with the LEDs so the image destined for the left eye alternates with the one for the right. In this case, optics handle the redirection, unlike glasses-based 3D systems where the glasses handle the filtering and synchronization. The film’s optical characteristics are created to match the viewing depth.
One key feature is the lack of critical film orientation. The film must be oriented at right angles to the LEDs, but tolerances aren’t tight compared to other optical approaches. Also, as with most 3D systems, the display must be updated at twice the normal speed. Likewise, 3D presentation is improved when both color depth and resolution are high. The latest crop of LCDs will be able to handle these tasks.
The increased bandwidth required for 3D support will likely be an issue, though new compression techniques could significantly reduce the overhead for offering 3D content. 3D content generated on the fly also requires more processing power, putting a burden on the underlying system. 3D hardware acceleration already available will help in this instance.
The display adapter technology will depend on the source of 3D content. 3D games and dynamically generated 3D content will require 3D hardware acceleration. Streaming content can be handled at the source, reducing the requirements at the destination, though this increases the bandwidth required or reduces the frame rate. Still, the availability of inexpensive 3D displays will make the delivery 3D content practical for handheld devices.