| 摘要 |
1531920 Television RCA CORPORATION 19 May 1976 [21 May 1975] 20713/76 Heading H4F A method of operating a CCD imaging array involves a charge integration period having a period when charges above a first level are removed from charge accumulating locations and a subsequent period then charges above a second, higher level are removed from the charge accumulating locations. In one embodiment, Fig. 4, the method is realized by application of a ramp voltage 20 which creates a continuously linearly deepening potential well in the CCD substrate. The method reduces the build up of charges due to "dark current" as seen in Fig. 3, in which the area under curve AA represents the dark current charge at a normal array location using the constant integration voltage of the prior art, that below curve A corresponds to the dark current charge at a normal array location operated according to the method. Areas under curves BB, and B represent respective dark currents at defective array locations. In the latter case the dark currents B are only 30% of those generated BB by prior art methods. The dynamic range of the array is increased as described w.r.t. Figs. 7 to 10 (not shown). Other useful integration voltage profiles are illustrated in Figs. 11 and 12 (not shown). The method permits partial or total "on chip" gamma correction as described w.r.t. Figs. 13 to 17 (not shown). The integration voltage profiles illustrated are applied to the relevant one of the phased electrodes superposing the derived potential well. Alternatively complementary profiles may be applied to adjacent electrodes to vary a potential barrier, permitting charge disposal in accordance with the method Fig. 16 (not shown). The method may be applied to other forms of images such as those employing photo diodes, charge injection devices or vidicons.
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