NEC develops high-resolution 3D display

NEC Corp. unveiled a new LCD structure for 3D displays that promises high resolution at 470 horizontal pixels per inch. NEC presented the technology at the Asia Display/IMD '04 exhibition this week in Daegu, South Korea.

The prototype, a 2.5-inch low-temperature polysilicon LCD, has a new pixel arrangement called HDDP (horizontally double-density pixels). Combined with a lenticular lens, HDDP generates 3G effects in a simple structure.

Conventional color LCDs have a square pixel which is usually divided vertically into three dots: red, green and blue. NEC researchers divided the square pixel horizontally into three red, green and blue dots. It is then divided vertically into two sub-pixels to form right- and left-eye pixels. High resolution and a high aperture ratio (brightness) are trade-offs. But by dividing a pixel horizontally, NEC researchers say they achieved 470 horizontal ppi resolution without significantly lowering aperture ratio.

To display 3D images on LCDs, pixels are used alternately for the left and right eyes, meaning horizontal resolution is halved. Typical color displays for mobile phones are 2.2- to 2.5-inch QVGA, with resolution of about 180ppi. Nobuaki Takanashi, principal researcher of NEC's SOG Research Laboratories, said, "A low- resolution display cannot generate a high-quality 3D effect. The HDDP display has high resolution, especially horizontally, and can generate realistic 3D effects."

The display does not require switching to change from 2D to 3D. To display a 2D image, a pair of sub-pixels displays the same image.

"We hope this display works as a trigger to enlarge the 3D market," said Hideki Asada, senior manager of NEC's SOG lab. NEC plans to use the 3D display technology in mobile phone displays.

The lab has focused on system-on-glass LCDs. It announced a prototype LCD with power circuitry integrated on the glass in May 2003. The 3D panel combines SOG's technology and high-resolution display technology, Asada said.

NEC has since shifted volume production of amorphous LCDs to China, and no longer owns volume production lines for low-temperature polysilicon LCDs. Hence, it has not disclosed a strategy for 3D panel production based on low-temperature polysilicon.

- Yoshiko Hara

EE Times