Method of manufacturing a scanning device with adjustable frames

Abstract

The invention relates to a method of manufacturing a scanning device comprising a support ( 9 ) for an information carrier ( 1 ), a motor ( 13 ) for rotating the support about an axis of rotation ( 11 ), a scanning unit ( 15 ) for scanning the information carrier, and a displacement device ( 19 ) for displacing the scanning unit relatively to the information carrier. According to this method, the motor and the displacement unit are each provided on a separate frame ( 29, 31 ), and the scanning device is provided with a pretensioning means ( 39 ) and an adjusting device ( 33, 35, 37 ). In at least one adjustment position, the frames are held at a mutual distance under the influence of a pretensioning force exerted by said pretensioning means, said distance being adjusted by means of said adjusting device. The adjusting device is used to correct an angular deviation present between a laser beam path ( 27 ) of the scanning unit and a normal to an information surface ( 7 ) of the information carrier as a result of manufacturing tolerances. According to the method in accordance with the invention, an adhesive ( 73, 75 ) is applied between the two frames adjoining the adjusting device, and the distance between the two frames, as adjusted by means of the adjusting device, is secured by curing the adhesive present between the two frames. In this manner, unwanted mutual displacements of the two frames, which could occur as a result of imbalance forces caused by the information carrier rotating at relatively high speeds, are prevented as much as possible.

1 . A method of manufacturing a scanning device comprising a support for an information carrier, a motor for rotating the support about an axis of rotation, a scanning unit for scanning the information carrier, and a displacement device for displacing the scanning unit relatively to the information carrier, according to which method the motor and the displacement device are each provided on a separate frame, and the scanning device is provided with a pretensioning means and an adjusting device, both frames being maintained at a mutual distance in at least one adjustment position, viewed in a direction parallel to the axis of rotation, under the influence of a pretensioning force of the pretensioning means, and said distance being adjusted by means of the adjusting device, characterized in that an amount of an adhesive is provided between the two frames at a location near the adjusting device, the adjusted distance between the two frames being secured by curing the adhesive provided between the two frames.  
     
     
         2 . A method as claimed in  claim 1 , characterized in that the amount of adhesive is provided in an interspace between the adjusting device and the pretensioning means.  
     
     
         3 . A method as claimed in  claim 1 , characterized in that said distance is adjusted by rotating a screw of the adjusting device, which screw is screwed into a screw hole of a first one of the two frames, which screw hole extends substantially parallel to the axis of rotation, and which screw is provided with a head against which a second one of the two frames rests under the influence of the pretensioning force, a further amount of adhesive being provided in the screw hole, and the screw being secured, after adjusting said distance, in the screw hole by curing the adhesive provided in the screw hole.  
     
     
         4 . A scanning device manufactured in accordance with a method as claimed in  claim 3 , characterized in that the scanning device is provided with an adjusting device in three adjustment positions, a first one and a third one of the adjusting devices being arranged, on a Y-axis, so as to be diametrically opposed, with respect to the axis of rotation, said Y-axis extending perpendicularly to the axis of rotation, and a second one of the adjusting devices being arranged on a X-axis extending perpendicularly to the axis of rotation and the Y-axis, while the first, the second and the third adjusting device are provided with, respectively, a first, a second and a third cylindrical guiding sleeve, which are provided on the first frame and each comprise the screw hole of the relevant adjusting device, and with, respectively, a first, a second and a third cylindrical supporting element, which are provided on the second frame and are guided around, respectively, the first, the second and the third guiding sleeve, the second frame resting against the heads of the screws of the three adjusting devices through the help of the three supporting elements and under the influence of the pretensioning force.