Canon Kabushiki Kaisha

Kiyoshi Ikuta

Michio Hirohata

Kazuo Ikawa

Shinya Yomogizawa

A distance measuring device determines the distance to an object. A position detector detects the position of a signal reflected off an object. The position detector has a plurality of outputs wherein the ratio between the outputs vary in accordance with the position of the reflected signal. The ratio is obtained from the ratio of a period of time required for an ascending integration to a period of time required for a descending integration. A control circuit causes the ascending integration and descending integration to be performed repeatedly a plural number of times and obtains the receiving position from the ratio of the periods of time required for the plural number of times of the ascending integration and the descending integration.

Distance measuring device

In a distance measuring device for measuring a distance to an object by projecting a signal light and by receiving the reflected light thereof, at least two light emitting elements are arranged for projecting the signal light; a common drive source is provided for driving the two light emitting elements; and a control circuit is arranged to prevent the two light emitting elements form simultaneously lighting up.

A distance measuring device of the dual integration type in which a signal light is projected onto an object whose distance is to be measured has light receiving means receptive of the reflection of the signal light from the object and produces two output signals of variable ratio depending on the object distance. After either or both of the two outputs have been integrated for a first integration time, an integrated value for the first integration time is reversely integrated by an output of the light receiving means different from the output or outputs which have been integrated for the first integration time, so as to measure the distance to the object by seeking a second integration time required until the integrated value for the first integration time has reached a predetermined value by the reverse integration. The present invention proposes detecting means for detecting whether or not an integration level in the first integration time has reached the predetermined value, and integration time variable means for varying the first integration time in accordance with a period of time required for the integration level in the first integration time to reach the predetermined value.

Dual integration type electro-optical distance measuring device wherein

The present patent application discloses a flash device for camera, or a camera, including a light emitter for flash photography mounted about a pivot shaft on the camera body and a light condenser mounted about a pivot shaft on the photographic lens barrel which moves to vary the light distribution characteristics of the light emitter as the focal length of the photographic optical system varies, wherein when the flash device is in use, the light condenser moves as the focal length of the photographic optical system varies, thus making it possible to obtain the light distribution characteristic which is suited to the focal length of the photographic optical system, while when not in use, the light emitter and the light condenser are turned to be integrally housed in an appropriate plate of either the lens barrel or the camera body.

Flash device for camera

A battery check device for a camera which is capable of accurately making a battery check without being affected by temperature comprises detecting means for detecting the service condition of a battery; comparison means for comparing the detection value obtained by the service condition detecting means with a reference value; informing means for informing the photographer of the service capacity of the battery in response to the output of the comparison means; and changing means for changing the reference value to change thereby the informing state of the informing means according to temperature.

Battery check device for camera

This patent application discloses a device for protecting the photographic optical system of a camera having a first detector for detecting that the back cover of the camera is open or closed and a second detector for detecting whether or not the film is winding on the takeup spool, wherein when that the back cover is open or that the film is not winding on the spool is detected by the first and second detectors, either the rear of the photographic optical system is shut off, or the photographic optical system is moved forward, so that the rear vertex of the photographic optical system is prevented from being touched with a finger or the edge of the film leader.

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Tokyo, Japan

Kiyoshi Ikuta