The diamond pixel pattern of Sony's ClearVid CMOS sensor is featured on small-chip camcorders including the HXR-NX5U and HVR-Z5U.
Physics can be a harsh taskmaster. It constantly forces image sensor designers to walk the line between high resolution (which requires smaller photosites for a given imager size) and high sensitivity, signal-to-noise ratio and exposure latitude (which all favor larger photosites). In small-format sensors, the challenges are especially severe. While Sony engineers must respect the laws of physics, creative designs can give us a little wiggle room. Sony's ClearVid design rotates the conventional pixel array by 45 degrees and employs diamond-shaped photosites to address the specific challenges of small-format sensors.
Challenge #1: The lens
While Moore's Law enables smaller and smaller image sensors, there is no Moore's Law for lenses. For example, achieving full 1080p resolution on a Super 35mm digital sensor requires a lens that resolves about 41 line pairs per mm. This is relatively easy. Move to the 2/3-inch type sensor common to television broadcast cameras and you'll need a 100 line pairs per mm. That's more challenging. Call it ironic, call it perverse, but the small, affordable 1/3-inch cameras need spectacular lens resolution-184 line pairs per mm-to achieve full 1080p. This performance is seldom achieved in the real world.
Challenge #2: Diffraction
A second stumbling block in small sensors is inherent in the wave nature of light. Diffraction causes light to bend as it passes an edge, such as the blades of a camera's iris. The diffraction becomes worse as the iris stops down and worse at longer wavelengths (the red end of the spectrum). What should appear on the image plane as a point becomes a blurry circle called the Airy Disk. Diffraction is much more likely to cause image blurring on a small sensor because the photosite squares are so much smaller in comparison to the Airy Disk size.