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US 6,147,811 AGranted
Image reading apparatus
AssigneeCanon Kabushiki Kaisha
InventorKazuo Fujibayashi
Life of this patent
Estimating the term…
Abstract
In an image reading apparatus, an original is illuminated and an image of image information on the original surface is formed on a surface of a line sensor by an imaging system. The imaging system includes a zoom lens each element of which is so constructed as to obtain a predetermined effective F-number on a side of the line sensor of the zoom lens independently of zooming. The zoom lens has an aperture stop the diameter of which is adapted to change in synchronism with zooming to obtain a predetermined effective F-number on the side of the line sensor.
Claims9
An image reading apparatus comprising:
- illumination means for illuminating an original surface;
- a line sensor;
- and
- imaging means for forming an image of image information on the original surface on a surface of said line sensor, said imaging means comprising a zoom lens,
- wherein each element of said zoom lens is so constructed as to obtain a predetermined effective F-number of said zoom lens on a side of said line sensor independently of zooming.
2 more elements
Dependencies are inferred from the claim text.