We are advancing the development of ultrahigh-speed, high-sensitivity CCDs for broadcast use that are capable of capturing smooth slow-motion videos in vivid colors even where lighting is limited, such as at professional baseball games played at night. We have already developed a 300,000 pixel, ultrahigh-speed CCD, and a single CCD color camera that has been used for sports broadcasts and science programs using this CCD. However, there are cases where even higher sensitivity is required, such as when using a telephoto lens during a baseball broadcast or a high-magnification microscope during science programs. This paper provides a summary of our experimental development aimed at further increasing the sensitivity of CCDs using the light-collecting effects of a microlens array.
Fabrications of free form surface and well array plate demonstrated using glass material by imprint lithography. A metal mold is processed by a Diamond cutting. Using a low Tg glass plate, the mold is pressed to the glass surface and transferred the free form surface. The feature error of the proceed glass surface is within 200nm in 3mm x 6mm field. On the other hand, deep well array for bio-chemical device is transferred on glass surface using ceramics mold. Micro wells with 200 x 200μm in square and 50 μm in depth is achieved without fatal defect using optimized imprint process conditions.
Low-cost micro fabrication technique is indispensable for mass production of micro optical elements. Si very large-scale integration (VLSI) fabrication technology such as electron beam lithography or advanced photo lithography is generally applied to fabricate micro structures, however the production cost is too expensive for mass production of optical elements. To overcome the problem, imprint lithography is one of the promising method to fabricate micro structures at low cost. Various shaped mold is fabricated by semiconductor process technology. Process conditions such as temperature or pressure are designed to avoid fracture of the glass plate. Fine gratings, fine blazed and various shaped structures are successfully achieved on the glass surface without fatal defects. The cross-sectional profile of the imprinted structure is fairly good and surface roughness is less than a few nano meters.