Abstract: An optical disc on or from which information signals are recorded/reproduced by irradiation of a laser light beam is disclosed. The optical disc has a plurality of top surfaces, a plurality of bottom surfaces, and a plurality of portions formed on a major surface of a disc substrate of the optical disc. The portions separate the top and bottom surfaces from each other. A recording track is constituted by each top surface and each bottom surface. Each bottom surface and each top surface have a first width, while each portion has a second width. The recording track has a track pitch P defined by the sum of the first width and said second pitch. The pitch is related with the second width and the spot diameter of the playback light &phgr; by a formula and P<&phgr;/2 and 0.1 &mgr;m<second width ≦&phgr;/2.5.

Abstract: A consumer supplies personal information such as his/her name and merchandise to be purchased, recorded in his/her personal information terminal, to an information processing part of a store or a corporation such as a maker or a service provider through a connection interface provided on the store front or a network. The consumer receives advertisement related to merchandise and/or service responsive to his/her demand from the corporation, so that the personal information is effectively applied to business and industry. Thus, a personal information application system is so provided that each consumer can readily obtain advertisement of merchandise and/or service responsive to his/her demand and a corporation can readily obtain information about needs and trends of purchase of consumers.

Abstract: In a semiconductor substrate surface, first and second trenches extending in parallel with each other in a bit line direction are provided. An insulation film for trench isolation is filled in the first and second trenches. A floating gate is provided between the first and second trenches on the semiconductor substrate. A sidewall spacer is provided on a sidewall surface, extending in the bit line direction, of the floating gate.

Abstract: A magneto-optical reproducing apparatus for reproducing from a magnetic film medium having at least a displacement layer, a switching layer, and a memory layer. A magnetic wall displacement is generated in the displacement layer in any region where the temperature exceeds the Curie temperature of the switching layer to effectively enlarge any recorded magnetic domain. The reproduced signal from the magnetic film medium is equalized with regard to waveform in an equalizer circuit and then fed to a magnetic wall displacement detection circuit that produces a magnetic wall displacement signal by using a differential signal or a secondary differential signal of the reproduced signal so as to provide a low bit error rate despite any sudden DC level variation in the reproduced signal.

Abstract: An electronic service system is formed such that the personal authentication information such as user ID and password registered at one site can be utilized in carrying out the electronic commerce or the electronic service at another site, by transferring the user information between a plurality of EC sites safely.

Abstract: An optical pick-up generates a 0-th order diffraction light and ±1st order diffraction lights by a diffraction grating and irradiates the same to an optical disc. The ±1st order diffraction lights have phase distributions equivalent to a wavefront aberration of the optical disc when there is a tilt in the optical disc. Distances between the center of the main optical spot and centers of sub optical spots in a disc radial direction on a recording surface are whole multiples of a track pitch. The generation circuit generates a main push-pull signal corresponding to the 0-th order diffraction light and first and second sub push-pull signals corresponding to the ±1st order diffraction lights and generates tracking error signals TE as differential push-pull signals obtained by subtracting a sum signal of the first and second sub push-pull signals from the main push-pull signal.

Abstract: Memory cell gates are formed on the main surface of a semiconductor substrate via a gate isolation film. Source regions and drain regions are formed on both sides of the memory cell gates. The source regions have p− impurity regions and n+ impurity regions while the drain regions have p− impurity regions and n+ impurity regions. And the concentration of the p− impurity regions is made higher than the concentration of the p− impurity regions while the concentration of the n+ impurity regions is made higher than the concentration of the n+ impurity regions.

Abstract: A tilt detection apparatus capable of detecting the tilt of the optical disk, provided with a laser for outputting a laser beam, a diffraction grating for diffracting the laser beam from said laser to generate a 0th order diffraction beam and +-first order diffraction beams which have the phase distribution equal to the phase distribution due to the wave front aberration generated on an optical disk when the optical disk is tilted, an objective lens for collecting said diffraction beams and exposing the beams to the optical disk, a photodetector for generating signals corresponding to said +-first order diffraction beams reflected at said optical disk, a signal generation circuit for generating the push-pull signals based on the generated signals, and a tilt detection circuit for detecting the tilt of the optical disk based on the push-pull signals.

Abstract: A recording and reproduction apparatus using a plurality of generations of optical recording media and an optical recording medium used in such a recording and reproduction apparatus, wherein the optical recording medium comprises first and second recording areas, the first recording area is divided into a plurality of zones, each of the plurality of zones is divided into a plurality of divided areas of one type among a plurality of types set in advance, the plurality of divided areas are assigned addresses and have fixed recording capacities, and identification information indicating the one type is recorded in the second recording area. The apparatus focuses a laser beam on the second recording area to read the identification information and records information on the first recording area or detects recorded information of the first recording area based on the identification information. The optical recording medium is for example a magneto-optical disk.

Abstract: A packet processing and packet transfer scheme capable of reducing the packet processing overhead by eliminating a need to decrypt and re-encrypt the entire packet at a time of relaying encrypted packets. In a packet processing device for relaying encrypted packets, a packet transferred to the packet processing device is received, where the packet has a packet processing key to be used in a prescribed packet processing with respect to a data portion of the packet, and the packet processing key is encrypted by using a first master key shared between a last device that applied a cipher communication related processing to the packet and the packet processing device.

Abstract: An interlayer insulating film is formed by the CVD method to cover a side surface of lower floating gate, and the top surface of said interlayer insulating film is planarized. An upper floating gate is formed extending over lower floating gate and interlayer insulating film. A control gate is formed on upper floating gate with an insulating film therebetween.

Abstract: A mobile computer and a packet encryption and authentication method which are capable of controlling an activation of a packet encryption and authentication device belonging to the mobile computer according to the security policy at the visited network of the mobile computer. The mobile computer is provided with a packet encryption and authentication unit having an ON/OFF switchable function for applying an encryption and authentication processing on input/output packets of the mobile computer.

Abstract: A mobile computing scheme capable of carrying out a proper packet transfer according to a current location of the mobile computer by accounting for the network operating policy. A mobile computer carries out a prescribed communication processing according to recognition results as to whether the mobile computer is located inside or outside the home network at which a mobile computer management device of the mobile computer is provided, and whether or not there exists a packet processing device which has a packet transmitted by at least one of the mobile computer and a correspondent computer as an encryption and authentication processing target.

Abstract: A packet transfer scheme for realizing a control of a packet inspection device to pass only packets from those mobile computers that can be recognized as authenticated among non-management target mobile computers that had moved inside the network, to outside the network.

Abstract: An optical pickup device for improving the numerical aperture of an objective lens and for assuring high-reliability recording/reproduction of information signals. The optical pickup device has a first lens 6 having a curvilinear or planar surface facing an optical recording medium 5 and having the numerical aperture set to a pre-set value, and a second lens 3 arranged for clamping the first lens 6 between t and the optical recording medium 5. The optical pickup device also has a light-converging optical system for converging the reflected light from the surface of the optical recording medium 5 and a first movement unit 2 for moving the first objective lens 6 and the second lens 3 along the direction of the optical axis with respect to the second objective lens 3.

Abstract: The invention relates to an optical disc apparatus more particularly relates to an optical disc apparatus which is suitably applied to an magneto-optic disc apparatus to reduce leakage of wobble signal to reproduction signal. To achieve the object, the signal level of the first and second beam quantity detection signals SI and SJ which generate the reproduction signal RF by use of the differential output is corrected based on the signal level SL of the wobble signal component detected from the reproduction signal RF and the phase detection result S.o slashed., or the wobble signal component is extracted respectively from the first and second beam quantity detection signals and subtraction is performed.

Abstract: A recording/reproducing apparatus for an optical recording medium which is used for recording and/or reproducing information on/from the optical recording medium by irradiating the optical recording medium with a laser light using two-group objective lenses comprising at least two lenses as the first and second lenses, is provided so as to comprise a light source emitting the laser light, the first lens for focusing the laser light emitted from the light source, the second lens arranged between the first lens and the optical recording medium, and a device for moving both the first and second lenses relative to each other to change the distance between them in the optical axis direction of the laser beam, so that the moving device moves the second lens to change the distance between the first and second lenses.

Abstract: An optical recording medium recording and reproducing apparatus for recording information on an optical recording medium and/or reproducing information therefrom by irradiating the optical recording medium with laser light by the use of a two-group objective lens composed of at least first and second lenses. This apparatus is provided with: a light source for emitting laser light; a first lens for converging laser light emitted from the light source; a second lens interposed between the first lens and the optical recording medium; a detecting unit for detecting a kind of the recording medium; and a movement unit for changing the distance in the direction of an optical axis between the first and second lenses by causing a relative movement between the first and second lenses. Further, the distance between the first and second lenses is changed by the movement unit, which causes the second lens to move, according to a result of a detection, which is performed by the detecting unit.

Abstract: A magneto-optical recording medium has a substrate and a magneto-optical recording film. The substrate is formed from material having light transmittivity. On one surface of the substrate there is provided a magneto-optical recording film. In said one surface of the substrate where the magneto-optical recording film is provided, when a wavelength of a light beam, irradiated on the magneto-optical recording medium, is .lambda., there are formed grooves having an optical depth where its lower limit is .lambda./8 and its upper limit is .lambda./4 or less. The magneto-optical recording film is formed so that the Kerr ellipticity thereof becomes 0.degree..

Abstract: A magneto-optical recording medium formed to record an information signal on both of lands and grooves provides a capability of reproducing an excellent signal with a small magnitude of crosstalk even by narrowing a track interval more. In the magneto-optical recording medium, an optical depth d of each groove is in the range of (1/12+n/2).lambda..ltoreq.d.ltoreq.(1/6+n/2).lambda. or {-1/6+(n+1)/2}.lambda..ltoreq.d.ltoreq.{-1/12+(n+1)/2}.lambda., where .lambda. is a wavelength of a light beam to be applied onto the recording medium and n is an integer of 0 or more. When reproducing the information signal from the medium, a phase difference is given to the return light from the medium before detecting the return light.