One image good, three images better?
One Screen, Three Images
Sharp Corp., of Osaka, Japan, pioneer of the desktop calculator, the personal digital assistant, and the camera phone, now offers yet another first: an LCD that gives three distinct images to three different people standing left, right, and center. Last year’s model, which gave only two views, now enables the driver of some Toyota cars to check the route map while the front passenger uses it to look up information on restaurants and shops.
What good would a third image be? Sharp sketches a scenario—perhaps a little strained—in which a passenger in the rear watches a DVD movie while those in front look at two other images. More practical, it seems, would be signs that show successive advertisements to people who pass by on foot or on an elevator, much as the famous Burma-Shave billboards did for drivers decades ago.
At the heart of the technology lies a parallax barrier, a series of precisely positioned vertical slits that project light from the pixels in different directions. This method has been used in stereoscopic displays, which present the right and left eyes with distinct views, taken from slightly different points, to create a sense of depth. Sharp’s patented parallax system goes further by diverting the images widely enough to cater not just to one person’s eyes but to three people’s.
The prototype display measures 8 inches diagonally and provides an overall resolution of 1600 by 480 pixels, of which the three images have an equal share. Although that leaves each image with just 533 by 480 pixels, they all appeared clear and bright at the demonstration.
Sharp also exhibited a 5-centimeter (2-inch) LCD to serve as both the main and the subdisplay in a clamshell cellphone design. By sandwiching a single backlight unit between two LCD panels, the design not only saves the cost of including and running an extra light but also achieves a total thickness of just 2.07 millimeters.
Both the main display and subdisplay provide the same high 240 by 320 resolution. Sharp says it will produce the panel in three sizes: 5.1 cm, 5.6 cm and 6.1 cm.