Abstract: The invention pertains to a method for examining a series of objects that are symmetrical in reference to a rotational axis, e.g., circular disks, during or after the manufacturing process of the disks. In particular, the invention pertains to the optical examination of circular data carriers, e.g., CD, DVDs, CD-Rs or the like. The invention proposes that each object contains at least one marking or is provided with at least one marking. The marking makes it possible to unequivocally determine the angular position of each object about the rotational axis in reference to the marking for objects manufactured in the same manufacturing process. At least one section of the objects is scanned by at least one scanning element, and the marking is detected during the examination process.

Abstract: A method for the inspection of an article which has a relatively large surface-area and which has at least two opposing, partially transparent, outer layers and at least one intermediate layer located between the outer layers. In particular, the method is utilized to optically inspect optical data media, for instance, DVDs, having the above referenced multilayer structure. The opposing sides of the article are sensed with at least two optical receivers, and the data of the recorded image points of the one optical receiver is allocated to the data of the recorded image points of the other optical receiver in such a manner that the data of the opposing points of the article are allocated to each other and can be evaluated. An identification of a potential error in the intermediate layer is possible when the data of the opposing image points indicate an error in the case of both optical receivers.

Abstract: Device for optical detection of the deformation of a surface with at least one photosensitive receiver having a matrix image plane, which is exposed by at least one light source. It is proposed according to the invention that the light source is constructed as a nearly point-source light with uncollimated light and in imaging optics are provided and adjusted such that the light source is imaged sharply onto the image plane (14) of the photosensitive receiver, so that the surface to be examined acts as a reflective surface, the light source having a known nominal position on the image plane in case of a flawless surface being examined, so that the deformation can be determined from the deviation of the actual position of the image of the light source from the known nominal position of the image of the light source on the image plane. With this arrangement, a deformation, in particular, an erroneous inclination of a CD or DVD, can be detected with high precision and by simple means.

Abstract: A rotary drive device for a flat object which is transported by a conveyance means to a processing station. At the processing station the object is rotated about an axis orthogonal to its surface extension by the rotary drive device. The rotary drive device includes a receptacle for the object and an axially projecting guidance means which cooperates with a hole in the object to center the object. When the object is positioned on the conveyance means above the receptacle, the object can be connected to the receptacle free of rotational play by a releasable fixation means. The receptacle is arranged on a rotatable plunger that can be moved back and forth so that elaborate pivoting and lowering motions of the conveyance means is not required.