Sharp Offers 3-D Viewing Without Glasses

The technology works best in small displays

3 min read

9 April, 2010—Last Friday, Sharp Corp. took the wraps off a 3-D display technology that doesn't require special glasses but produces an image as bright as what you'd see on a standard LCD screen. Sharp says it will begin mass-producing small displays, suitable for mobile devices, in the next six months and predicted that it wouldn't be long before the technology replaces standard mobile displays.

Sharp's bet on 3-D comes hard on the blue 3-D heels of Avatar, the highest-grossing movie ever, and in the wake of the March launch of 3-D TVs from Japan's Panasonic and South Korea's Samsung. Sony says it will ship its 3-D LCD TVs in June, just in time for the World Cup soccer tournament, which ESPN will use to kick off the industry's first 3-D television network.

Sharp has been here before: In 2002, it introduced the first generation of spectacles-free 3-D displays, a launch that was followed by decidedly one-dimensional sales. Those displays were too dim, too thick, and too rigid; the image could not be rotated from portrait to landscape mode. Besides, there was little 3-D content then for people to watch.

"We knew that if we could overcome these challenges, we could be successful," said Yoshisuke Hasegawa, executive manager in charge of Sharp's LCD operations, at the unveiling of its new display on 2 April.

The live demonstrations of the new panels show that the company has made significant strides, judging by the 2-D–like brightness and resolution of both the still images and video animation provided by Sharp. The specifications also underscore the improvements. The older 3-D display targeting cellphones measured 2.4 inches (6.1 centimeters) with a screen resolution of 240 by 320 pixels, a brightness in 2-D mode of 250 candelas per square meter, and a contrast of 100:1. The new display measures 3.4 inches (8.6 cm), sports a resolution of 480 by 854 pixels, and has twice the brightness (500 cd/m2) and 10 times the contrast ratio (1000:1). It comes with an optional touch screen that lets you rotate the image, although Sharp did not demonstrate this feature.

Two advances account for most of the improvement. First, Sharp improved the "parallax barrier," an overlay of alternating transmissive and nontransmissive columns aligned with columns of LCD pixels to separate the two paths that light takes to the viewer's right and left eyes. Sharp's trick is to make the barrier electronically switchable through the addition of polarizing optics that can rotate the light, in effect switching the display from 2-D to 3-D, or vice versa. The technology was used in Sharp's first-generation 3-D displays, but the company has refined it, reducing ghosting and cross talk between the left eye and right eye images.

The drawback of using a barrier is that the screen must be viewed at its center and from a precise distance—in the case of the Sharp display, from 30 cm. This should not pose a serious problem for cellphone users, and it may even be acceptable for video-game players, but it wouldn't work for the large displays used in PC monitors and TVs.

The second improvement involves the use of continuous grain (CG) silicon, which was developed jointly with Semiconductor Energy Laboratory Co., in Japan. CG is a variant of polycrystalline silicon in which there is a reduced impediment to electron flow between the single-crystalline regions. The effect is to increase electron mobility to six times that of low-temperature polysilicon and to 600 times that of ordinary amorphous silicon, according to Sharp. The company can thus reduce the number of layers used in fabricating the panel and shrink the width of the wiring within the panel, allowing more light to pass through. The result: a brighter display.

Hasegawa says Sharp will use the panels in its own products and is currently negotiating to sell the panels to various product manufacturers. Noting that 2-D technology spread from the cinema to the home and then on to mobile devices, he adds, "we think the same will happen with 3-D." He predicts the technology will account for between 10 to 20 percent of Sharp's mobile displays this fiscal year and up to 50 percent next year.

In March, Nintendo announced that within the next 12 months it would release a 3-D version of its popular DS handheld video-game player. The Japanese press, citing inside sources, says the display will come from Sharp and expects the launch to happen in time for the 2010 holiday season.

About the Author

John Boyd writes about science and technology from Japan. In April 2010 he covered Sony's scheme for wirelessly connecting chips inside computers.

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