Automatic focusing apparatus and optical device
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Accused Products
Abstract
The present invention is directed to the provision of an automatic focusing apparatus that can detect a focusing point at a sufficiently high speed for practical use and can achieve a lens condition having good focusing performance. The automatic focusing apparatus of the present invention includes a liquid crystal lens which forms a refractive index profile, an optical-to-electrical conversion unit which converts an optical image focused through the liquid crystal lens into an electrical signal and outputs the electrical signal as an image signal, a focus signal extracting unit which causes the refractive index profile to change by applying a first range of voltage to the liquid crystal lens, and extracts a plurality of focus signals based on the image signal, a focusing point identifying unit which identifies a focus signal corresponding to a focusing point from among the plurality of extracted focus signals, and a focusing point adjusting unit which adjusts the focusing point by applying to the liquid crystal lens a second voltage that is capable of generating the refractive index profile corresponding to the focus signal identified by the focusing point identifying unit and that is smaller than the first range of voltage applied to the liquid crystal lens in order to obtain the focus signal identified by the focusing point identifying unit.
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Citations
32 Claims
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1-16. -16. (canceled)
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17. An automatic focusing apparatus comprising:
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a liquid crystal lens which forms a refractive index profile; an optical-to-electrical conversion unit which converts an optical image focused through said liquid crystal lens into an electrical signal and outputs said electrical signal as an image signal; a focus signal extracting unit which causes said refractive index profile to change by applying a first range of voltage to said liquid crystal lens, and extracts a plurality of focus signals based on said image signal; a focusing point identifying unit which identifies a focus signal corresponding to a focusing point from among said plurality of extracted focus signals; and a focusing point adjusting unit which adjusts the focusing point by applying to said liquid crystal lens a second voltage that is capable of generating the refractive index profile corresponding to the focus signal identified by said focusing point identifying unit and that is smaller than said first range of voltage applied to said liquid crystal lens in order to obtain the focus signal identified by said focusing point identifying unit. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. An optical device comprising:
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a liquid crystal lens which forms a refractive index profile; a focus signal extracting unit which causes said refractive index profile to change by applying a first range of voltage to said liquid crystal lens, and extracts a plurality of focus signals based on an image signal converted from an optical image focused through said liquid crystal lens; a focusing point identifying unit which identifies a focus signal corresponding to a focusing point from among said plurality of extracted focus signals; and a focusing point adjusting unit which adjusts the focusing point by applying to said liquid crystal lens a second voltage that is capable of generating the refractive index profile corresponding to the focus signal identified by said focusing point identifying unit and that is smaller than said first range of voltage applied to said liquid crystal lens in order to obtain the focus signal identified by said focusing point identifying unit.
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Specification