Focus detecting device
AssigneeMinolta Camera Kabushiki Kaisha
InventorYasuhiro Nanba
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Abstract
A photoelectric focus detecting member includes a semiconductor substrate of a first polarity and at least two closely transversely spaced parallel longitudinally extending photosensitive laminae of a polarity opposite to the first polarity to form corresponding photodiodes. Each of the photosensitive laminae is masked to provide regularly spaced light receiving areas alternating with masked areas, the light receiving areas of successive transversely spaced photodiodes being relatively longitudinally offset to present a checkered pattern. The detecting element is positioned in the focal plane of a lens and is either stationary or oscillated. The difference in potential between the diodes or the amplitude of the AC current in a circuit including the photodiodes is a function of the condition of focus of the lens.
Claims12
A focus detecting element positioned at a plane intended to be focussed by a lens for receiving light through the lens to produce an electrical signal, characterized in that said element comprises at least one pair of photodiodes elongated in longitudinal directions parallel to each other, each of said photodiodes having a light receiving surface divided into a plurality of longitudinally spaced areas along the elongated direction of said photodiode, the areas of one of said pair of diodes being longitudinally offset with respect to the areas of the other of said pair of diodes.
A focus detecting device comprising first and second side-by-side longitudinally extending sets of photoresponsive elements, the photosensitive elements in each set being longitudinally spaced from each other and being longitudinally offset relative to the phtosensitive elements in the other set.
Dependencies are inferred from the claim text.