Minolta Camera Kabushiki Kaisha

Takayuki Gotoh

Toshihiko Karasaki

Eiji Yamakawa

Yasuhiro Nanba

Yasuhiro Namba

A focus detecting photoelectric device includes a plurality of photodiodes each formed by an amorphous silicon layer sandwiched between transparent and non-transparent electrodes. The photodiodes are provided in pairs and are aligned in an array and deposited on a glass plate such that the transparent electrode is directly mounted on the glass plate. The photodiodes in a pair are located closely adjacent to, but in a spaced relation with, each other and are electrically connected in series to each other. An image formed on the photodiodes in a pair effects the generation of photocurrent from the photodiodes such that the photocurrents from both photodiodes are approximately the same when the image is out of focus, and they vary from each other as the image becomes sharp.

Focus detecting photoelectric device and focus detecting system

The disclosure relates to a focus detecting device for detecting a focusing condition of an objective lens on a focal plane by the detection of contrast of an image formed by the objective lens. The device includes an elongated biconcave cylindrical lens for forming a line image, a glass plate positioned parallelly to the cylindrical lens, and a plurality of photodiodes deposited on the opposite flat surfaces of the glass plate in arrays parallel to the axial direction of the elongated cylindrical lens such that the photodiode arrays on the opposite flat surfaces are disposed alternately in an interlaid manner. When the line image formed on the photodiodes deposited on one surface of the glass plate is front-focus condition and the line image formed on the photodiodes deposited on the other surface of the glass plate is rear-focus condition, a detector indicates that the line image formed on a plane between the opposite flat surfaces is in-focus condition.

Growing community of inventors

Osaka, Japan

Takayuki Gotoh