GearBits

400 Pixels Per Inch for Cellphone Screens

Samsung has demonstrated a 2-inch LCD panel with an equivalent resolution of 400ppi, yielding a VGA-equivalent-quality screen for use in cellphones.

Samsung's screen is based on Si-TFT technology. While the number of pixels in the panel is 240 x 640, the high-resolution display is theoretically equivalent to VGA (400-ppi, 480 x 640 pixels) was achieved by a special Four Color Rendering (4CR) technique, proprietary to the company.

The 4CR realizes high resolution equivalence with fewer pixels by utilizing RGB sub-pixels on adjoining scan lines in color and gradient renderings.

A similar technique called field sequential (FS) rendering divides pixels sequentially, displaying colors in the order of RGB.

Samsung has already demonstrated several LCD panels featuring FS rendering, technique, but this is one of the few using 4CR, and the first with this level of resolution, 10x earlier models.

Samsung claims a luminance of 200cd/m2, a contrast ratio of 200:1, and 262,000 colors, with color reproduction area against NTSC at 70%.