Abstract: Optoelectronic devices in which optoelectronic components comprising a diode laser are fastened on a carrier plate having good heat conduction, and in which the carrier plate is provided with connection conductors for the components which are separated from the carrier plate by an electrically insulating medium, are used inter alia in equipment for optical reading and/or writing of information carriers such as CD (audio) or CDROM. The known device is comparatively expensive, especially because of the necessity of using a special connector when a flexible connection is desired. According to the invention, the electrically insulating medium comprises a strip-shaped flexible foil which carries conductor tracks, extends over and beyond the carrier plate, is fastened on the carrier plate, and has a void above the carrier plate in which the diode laser is present.

Abstract: An optical scanning apparatus, which includes a radiation source (7) supplying a scaning beam (b.sub.1), an objective system (8) for focusing the scanning beam (b.sub.1) to a scanning spot (S.sub.1) in an information plane (2) to be scanned, and a first diffraction element (9) for deforming the beam reflected by the informatin plane (2) in such a way that a focus-error signal can be derived therefrom. The apparatus also includes a second diffraction element (10) for forming two auxiliary beams (b.sub.2, b.sub.3) by means of which a tracking-error signal can be derived, which second diffraction element has such a size and is arranged at such position that the beams originating from the first diffraction element (9) do not traverse the second diffraction element.

Abstract: Optical scanning apparatus which includes a diode laser producing a radiation beam which is focussed by a lens system on a reflecting information plane to be scanned thereby. The reflected radiation is diffracted by a composite diffraction grating which includes a pair of sub-gratings, forming respective radiation spots on respective pairs of radiation detectors. The detectors in each pair are separated by a separating strip, the separating strips being substantially parallel to or co-linear with the bonding line between the sub-gratings. Such arrangement achieves correction for wavelength variations of the radiation beam, as well as fairly wide tolerances in the relative positioning of the various optical elements of the apparatus.

Abstract: Apparatus for scanning a radiation-reflective information plane (2). A scanning beam of radiation (b) from a diode laser (4) is focused by an objective lens (6) on the information plane and the beam reflected therefrom is deflected by a composite diffraction grating (9) so as to form two asymmetrical radiation spots (V.sub.1, V.sub.2) respectively focused on respective pairs of photodiodes (18, 19; 20, 21). The relative outputs of the photodiodes in each pair control focusing of the scanning beam on the information plane. The photodiodes in each pair are separated by a strip (22',23') positioned so that it is at an acute angle to the line (22, 23) along which the asymmetrical reflected radiation spot formed on the relevant diode pair becomes displaced as a result of variations in the wavelength of the scanning beam. Such angle is set so the separating strip is on the line along which the center of the intensity distribution of such radiation spot becomes displaced as a result of such variations.

Abstract: An apparatus for scanning the information plane of an optical record carrier with a radiation beam from a diode laser. The reflected radiation from the information plane is separated from the scanning beam and split into two sub-beams by a composite diffraction grating which also functions to focus the respective sub-beams on respective pairs of photodetectors. The composite grating consists of two sub-gratings which adjoin along a common bounding line, the sub-gratings having varying gratings periods and curved grating strips. Movement of the composite grating in the direction of the bounding line changes the axial imaging distance of the sub-beams from the grating, permitting adjustment of such distance to compensate for changes in the axial distance between the diode laser and the photodetector. The diode laser and photodetectors can therefore be assembled together as a single integrated unit.