U.S. Philips Corporation

Hendricus F Van Tongeren

Marino G Carasso

Paulus Philippus Schampers

Jan W Kokkelink

Martin A Farla

Willem P Weijland

Johannes H Spruit

Bernardus A Jacobs

Johannes Cornelis Driessen

Hermanus A Van De Pas

Cornelis Gerardus Schriks

Piet F Bongers

Theodorus C Bertens

Johannes T Thijssen

Martinus M Sens

The invention relates to an optoelectronic device comprising a semiconductor laser enclosed in an envelope, an optical fibre coupled to the semiconductor laser, and further coupled to at least one optical isolator and an outgoing optical fibre (pigtail). According to the invention, the semiconductor laser and the optical isolator are each enclosed in a separate module. The laser module mainly provides space to the semiconductor laser and to an optical fibre coupled thereto and ending in a ferrule in a tubular projection of the laser module. The module for the optical isolator is tubular in shape and contains in that order a first graded index lens, an optical isolator, a second graded index lens, and an outgoing optical fibre (pigtail) coupled to this second graded index lens through a ferrule. The tubular projection of the laser module and an end portion of the tubular optical module are so shaped in relation to one another that a mechanical coupling of the two modules can be obtained whereby the optical coupling between the modules is achieved simultaneously.

Optoelectronic device comprising a semiconductor laser and an optical

When information is recorded on a record carrier (1) of the thermomagnetic type, the thermomagnetic recording layer (4) is scanned by a magnetic field generated by a magnetic-field modulator (7). The magnetic field is modulated depending on an information signal (Vi). Moreover, the scanned portion of the record carrier (1) is at the same time locally heated by radiation pulses (10) generated by an optical scanning device (5). By means of radiation pulses (10) the record carrier is heated above a write temperature (Ts), above which temperature the magnetization of the record carrier assumes the direction dictated by the magnetic field. A synchronizing circuit (9) generates the control signal (Vm) for modulating the magnetic field and the control signal (Vr) for generating the radiation pulses, in such a way that at the end of the radiation pulses the field strength is sufficiently high for the heated area of the record carrier to be magnetized in the directio dictated by the magnetic field.

Method of recording information on a record carrier of the

An optoelectronic device with a coupling is provided, comprising a lens (10), between an optical transmission fiber (13) and a semiconductor laser diode (2), which device is provided with a holder (1) for the laser diode, a holder (12) for the optical transmission fiber and an intermediate piece (16) present between these two holders, the spherical lens (10) being accommodated in the cover (9) of the holder (1) of the laser diode (2), while the holder (12) of the transmission fiber contains a hollow glass rod (14) in which a core portion (11) of the transmission fiber is accommodated, the end (15) of the glass rod and the fiber core being flat and polished, while the intermediate piece (16) has a sleeve shape and slides with exact fit over the cover (9) of the holder of the semiconductor laser diode (2), which sleeve-shaped intermediate piece has two grooves spaced some distance apart, at which grooves the intermediate piece and the cover of the holder of the semiconductor laser diode are fastened to one another by means of a number of laser welds after axial alignment, while furthermore the ends of the intermediate piece (16) and the holder (12) for the transmission fiber (11) facing one another have flat surfaces perpendicular to the axial alignment direction, which surfaces are fastened to one another with a plurality of laser welds after transversal adjustment.

Optoelectronic device having a coupling comprising a lens and arranged

A laminated product comprising substrate (7) and a thin layer (11, 12) of a dielectric compound formed from the oxide or the suboxide of gallium antimonide or indium antimonide, an optical information carrier containing such a thin layer, whereby said thin layer, dependent upon the oxygen content, may function as a recording layer 11 or as a transparent distance layer 12, as well as the suboxide of gallium antimonide or indium antimonide used in the laminated product.

Laminated product, compound used in the laminated product and optical

A method and apparatus are described for recording a binary information signal (FIG. 2a) on a record carrier (1) having an information layer (2) whose optical properties are modified upon heating. An information pattern corresponding to this information signal (FIG. 2a) is obtained in that the record carrier 1 is moved relative to an optical system (3) for focussing a radiation beam (4) on the information layer (2), a subsequent recording mark (5) being written on the information layer (2) in selected time intervals (.tau.) by locally heating the information layer by means of the radiation beam (4). The amount of radiation energy (E) applied in a selected time interval depends on the position of the selected time interval (.tau.) in the sequence of consecutive selected time intervals (.tau.). This provides compensation for the influence of the radiation energy (E) applied in the preceding time interval (.tau.) on the temperature at the location of the recording mark (5) to be written in the time interval (.tau.) so that for each recording mark (5) the temperature (T.sub.r) which is reached in the information layer (2) and hence the size of the recording mark (5) is substantially the same.

Binary optical signal recorder providing preheating pulse before an

A method and apparatus are described for recording a binary information signal on a record carrier having an information layer whose optical properties are modified upon heating. An information pattern corresponding to the information signal is obtained by moving the record carrier relative to an optical system which focuses a radiation beam onto the information layer. A recording mark is written on the information layer is selected time intervals by locally heating the information layer with the focussed radiation beam. The amount of radiation energy applied during a selected time interval depends on the position of the selected time interval in the sequence of consecutive selected time intervals. This provides compensation for the increase in the temperature at the location where the mark is to be recorded due to heating of the layer during recording of a mark in the preceding time interval. The amount of radiant energy that is applied is chosen so that for each recording mark the temperature which is reached in the information layer, and hence the size of the recording mark, is substantially the same.

Method of recording a binary signal on an optically readable record

The optical cross talk in a camera tube is reduced by the provision of a filter element which overlaps the entire target. The filter may is be arranged behind the target and is constructed so that it has low reflectance for incoming light. In order to prevent excessive transverse conduction, such a filter has a mosaic structure consisting of mutually insulated areas.

Camera tube with mutually insulated, light absorbing particles on gun

The optical cross-talk in a camera tube is reduced by the provision of a filter element which overlaps the entire target. The filter may be arranged in front of the photosensitive target and have a spectral transmission which is adapted to the spectral sensitivity of the target. The filter may also be arranged behind the target and preferably constructed so that it is also low-reflective for incoming light. In order to prevent excessive transverse conduction, such a filter may have a mosaic structure consisting of mutually insulated areas. Optical cross-talk may also be reduced by mounting the target on a support which is separately arranged in the camera tube and which has a small thickness.

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Eindhoven, Netherlands

Hendricus F Van Tongeren