Abstract: Recordable DVD+R and DVD+R/W optical discs with two (or more) information layers are developed to double the data storage capacity and video recording time. A method and device are proposed to make dual layer DVD disc recordings compliant with the dual layer DVD-ROM standard Recording the data in a DVD-ROM compliant way on the dual layer DVD+R or DVD+R/W disc is obtained by shifting the middle zone area towards the inner radius of a disc in such a way that the data zones of both layers are filled up with data.

Abstract: A multilayer record carrier is for recording information by writing marks representing addressable blocks in a track. Each recording layer has a pre-formed recording control pattern for indicating the track, the pattern comprising physical addresses (59) that indicate the physical position of the physical address with respect to a starting point of the track. The predefined number of bits of the physical address indicates the physical position with respect to a starting point of the track. At least one address bit of the predefined number of address bits of the physical address is allocated as a layer address bit (60) that has a value indicating the recording layer. A recording device has a layer unit (34) for detecting a recording layer in dependence of the layer address bit.

Abstract: A record carrier is for recording information by writing marks in a track on a recording layer. The shortest mark used for recording the information has a length of a predefined minimum number d of channel bit lengths. The record carrier (11) has a pregroove that is modulated by a carrier pattern containing long marks (18,19) that provides a focus area (12) at a predefined location on the recording layer. The long marks have lengths of at least two times the length of the shortest mark for being substantially longer than the effective diameter of the scanning spot. A scanning device locates the focus area and determines the best focus offset by detecting the maximum read signal amplitude while scanning the carrier pattern.

Abstract: A device has a head for recording information by writing marks in a track on a record carrier via a beam of radiation. The radiation is controlled to write the marks (40) having a main mark intensity (44) and a mark length within a predefined range of mark lengths. Further secondary marks (41) are recorded in the same part of the track. The secondary marks have a secondary mark intensity (43) that is substantially different from the main mark intensity and a length substantially longer than mark lengths in the predefined range. Furthermore a record carrier, method of recording and a read device are described.

Abstract: An optical data storage medium (10) for recording by means of a focused radiation beam (9) having a wavelength ? is described. The beam enters through an entrance face (8) of the medium during recording. The medium at least comprises a substrate (1), including a guide groove with a depth g. The guide groove is present at the side of the substrate opposite to the entrance face. A recording stack (2, 3) of layers is present adjacent the substrate (1) at the side of the guide groove. The stack includes a write once recording layer (2) of a material having a complex refractive index ñR=nR?i*kR at the wavelength ? and having a thickness dRG in the groove portion and a thickness dRL in the portion between grooves. A non-metallic layer (3) of a substantially transparent material, is present adjacent the write-once recording layer (2). The groove depth g is in the range (?/655)*20 nm<g<(?/655)*140 nm with ? expressed in nm.

Abstract: A multi-stack optical data storage medium (30) for recording and reading using a focused radiation beam (40) entering through an entrance face (41) of the medium (30) is described. It has a first substrate (31a) with present on a side thereof a first recording stack (33) named L0, comprising a recordable type L0 recording layer (35), formed in a first L0 guide groove (38a, 38b). A first reflective layer (39) is present between the first L0 recording layer (35) and the first substrate (31a). A second substrate (31b) with present on a side thereof a second recording stack (32) named L1 is present at a position closer to the entrance face (41) than the L0 recording stack (33) and formed in a second L1 guide groove (37). A transparent spacer layer (36) is sandwiched between the recording stacks (32, 33). The first L0 guide groove (38a, 38b) has a depth GL0<100 nm. In this way a relatively high reflection value of the L0 stack is achieved at a radiation beam wavelength of approximately 655 nm.