Sharp has newly developed CCD for the purpose to provide highly improved sensitivity and image quality compared with conventional one.
Sharp’s CCD is suitable for the surveillance camera which requires image capture with high visibility regardless of day and night, and other various monitoring applications.
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Light collection efficiency improvement technology
Collecting light efficiently |
The shape of each microlens of the CCD image sensor were optimized by Sharp’s unique forming
technology so that the efficiency to collect light can be improved, and as a result, the sensitivity has
greatly been improved. In addition, Sharp has realized high-quality images by optimizing device structure.
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| | ♦ Improved light collection efficiency of visible light and near-infrared light |
| | □Microlens shape optimization |
| | □Inner microlens shape optimization |
Photoelectric conversion efficiency technologies
Efficiently convert light to electric charges |
The additional feature of Sharp’s CCD is that, photoelectric conversion efficiency including near-infrared (NIR) light region has dramatically improved.
The light that was collected by microlens is converted to electric charge in a photoelectric conversion region of the CCD. Since the wavelength of NIR light is longer than visible light, most of NIR light pass through photoelectric conversion region. Therefore photoelectric conversion was theoretically difficult.
Sharp’s CCD makes it possible that NIR light is converted to electric charge efficiently by expanding photoelectric conversion region deeply.
Furthermore, comparatively more noise reduction is required than a visible light region, because the signal level of NIR light region is smaller than visible light region. Sharp’s CCD applies noise reduction technology based on output circuit optimization and it is able to capture high sensitivity and high quality images not only day and night, but also invisible dark situation by irradiating NIR light.
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| | ♦ Improved sensitivity of NIR light |
| | □ Photoelectric conversion region expands |
| | →By optimizing energy and injection angle of ion implantation |
Sensitivity characteristic comparison
Improving sensitivity for both visible light and NIR light |
| | Clearly observable in the dark by irradiating NIR light |
| | ♦Foreign material inspection (application example) |
| | Inspection is more accurate by NIR light rather than visible light. |
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