Abstract: The present invention provides, on the camera body side thereof, a pulse signal generator for generating continuous pulse signal trains, the frequency of which is four times the frequency employed for driving a supersonic motor and a pulse width which corresponds to the pulse width of an AC voltage for driving the supersonic motor. Furthermore, a unit detachable from the camera body and including the supersonic motor generates the AC voltage for driving the supersonic motor which corresponds to the pulse signal.

Abstract: The present invention provides a printed circuit board installed in a lens barrel with an imaging optical system. In an installed state, the printed circuit board comprises: a ring-shaped portion disposed substantially perpendicular to the optical axis of the imaging optical system wherein an aperture is provided at a central portion of the ring-shaped portion so that an imaging light beam may pass through the aperture; and an extending board portion that extends outward from the ring-shaped portion wherein electrical components may be mounted on the surface of the extending board portion. After the ring-shaped portion and the extending board portion have been bent, the above-described flexible printed circuit board is inserted into the lens barrel in such a manner that the plane of the extending board portion on which the electrical components are mounted is parallel to the optical axis of the imaging optical system.

Abstract: A drive circuit for an ultrasonic motor comprising:an oscillator;a periodic signal generator that divides the frequency of a clock sent from the oscillator and generates a periodic signal having a specified frequency;an ac voltage generator that uses the periodic signal to generate an ac voltage for driving the ultrasonic motor;a monitor device attached to the ultrasonic motor to provide a monitor output indicating an operating state of the ultrasonic motor;a timing signal generator that generates a signal in accordance with the timing that the ac voltage reaches a specified value within a period thereof;a comparator that in response to the timing signal sent from the timing signal generator, compares the monitor output with a specified value which is not zero; anda frequency control that controls the frequency of the periodic signal in accordance with an output of the comparator.

Abstract: Disclosed is a camera loaded selectively with either a first film having perforations formed in side edges or a second film having the same width as that of the first film and no perforations formed in side edges. The camera comprises: a picture size changeover device for selectively setting a photographing picture frame to a first picture size corresponding to the first film and a second picture size corresponding to the second film; a first lens installable and removable in and from the camera and having an image circle corresponding to the first picture size; a second lens installable and removable in and from the camera and having an image circle corresponding to the second picture size; and a device for judging which lens, the first lens or the second lens, to install in the camera. When the judging device judges that the first lens is installed in a state where the picture size is set to the second picture size, the picture size is so set as to be forcibly changed over to the first picture size.