# US 2010/0165804 A1 · Method and device for retrieving information from an optical record carrier at various reading speeds > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0165804 A1 - Document ID: US20100165804A1 - Status: Published application - Kind: A1 - Application number: 12/306,355 - Filed: 2006-07-04 - Published: 2010-07-01 - Earliest claimed: 2006-07-04 - Assignees: Koninklijke Philips Electronics N.V. - Inventors: Johannes H.M. Spruit; Bas Feddes; Jacob G. Nijboer; Paul Weijenbergh - Web page: https://patentgrep.com/patent/US20100165804A1 ## CPC - G11B 7/005: Reproducing (G11B7/0065 takes precedence) - G11B 7/126: Circuits, methods or arrangements for laser control or stabilisation - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract The present invention is related to a method and a reading device (1) for retrieving information from an optical record carrier (10) in which the read power level of a radiation beam (3) for scanning the optical record carrier is set in dependence on the read-out speed. The invention is also related to a record carrier for use with such a method and a reading device. ## Claims ### Claim 1 A method of retrieving information from an optical record carrier (10) comprising the steps of: setting a power level of a radiation beam to a predetermined read power level, scanning the record carrier by the radiation beam (3), detecting a reflected radiation beam reflected from the record carrier, and retrieving the information from the reflected radiation beam (9), characterized in that the power level of the radiation beam is set in dependence on a read-out speed to a read power level of ((1−α)+α√{square root over (n)})•PN where α is a predetermined parameter with 0.2<α<0.8, and PN is a read power level at a nominal read-out speed, and n is the actual read-out speed divided by the nominal read-out speed. ### Claim 2 (depends on 1) A method as claimed in claim 1, wherein the value of α is in a range between 0.33 and 0.50. ### Claim 3 (depends on 1) A method as claimed in claim 1, wherein said method further comprises a step of retrieving a value of the parameter α from the optical record carrier, and wherein the power level of the radiation beam is set in dependence on the retrieved value of the parameter α. ### Claim 4 (depends on 1) A method as claimed in claim 1 for retrieving information from a multi-layer optical record carrier, wherein the power level of the radiation beam is set for each information layer individually, each information layer having a predetermined parameter α to it. ### Claim 5 A reading device (1) for retrieving information from an optical record carrier (10) comprising a radiation source (2) for generating a radiation beam (3), a setting means (6) for setting a power level of the radiation beam to a predetermined read power level, a scanning means (5, 7) for scanning the record carrier by the radiation beam, a detector (4) for transferring a reflected radiation beam (9), said reflected radiation beam reflected from the record carrier, into an electrical signal (13), and a decoding means (8) for retrieving the information from said electrical signal, characterized in that the setting means is arranged for setting the power level of the radiation beam in dependence on a read-out speed to a read power level of ((1−α)+α√{square root over (n)})•PN where α is a predetermined parameter with 0.2<α<0.8, and PN is a read power level at a nominal read-out speed, and n is the actual read-out speed divided by the nominal read-out speed. ### Claim 6 (depends on 5) A reading device as claimed in claim 5, wherein the value of α is in a range between 0.33 and 0.50. ### Claim 7 (depends on 5) A reading device as claimed in claim 5, wherein said reading device further comprises retrieving means (8, 11) for retrieving a value of α from the optical record carrier, and wherein the setting means (6) are arranged for setting the read power level in dependence on the retrieved value of the parameter α. ### Claim 8 (depends on 3, 7) Optical record carrier (10) comprising an area consisting of patterns of optically detectable marks and of spaces between the marks representing parameter values indicative of properties of the record carrier, characterized in that said area comprises patterns of optically detectable marks and of spaces between the marks representing a value of α for use in a method as claimed in claim 3 or a reading device as claimed in claim 7. ### Claim 9 Optical record carrier as claimed in 8 comprising multiple information layers, wherein said area comprises patterns of optically detectable marks and of spaces between the marks representing values of the parameter α for each of the information layers.