# US 6,724,696 B2 · Four-axial driving actuator for optical pickup > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,724,696 B2 - Document ID: US6724696B2 - Status: Granted - Kind: B2 - Application number: 09/938,311 - Filed: 2001-08-24 - Published: 2002-06-13 - Granted: 2004-04-20 - Earliest claimed: 2000-12-08 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Seok-jung Kim; Yong-hoon Lee; Tae-yong Doh; Sun-mo Kim; Han-kook Choi - Web page: https://patentgrep.com/patent/US6724696B2 ## CPC - G11B 7/0932: {Details of sprung supports} - G11B 7/0935: {Details of the moving parts} - G11B 7/0956: {to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc} - 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 A four-axial driving actuator for an optical pickup with improved bobbin dynamic characteristics, in which the winding starting ports for a focus coil, tracking coil, and tilt coil are separate from one another, and the winding end ports thereof are combined as a common ground. The four-axial driving actuator includes: a base; a holder fixed on the base; a bobbin to which an objective lens is fixed; spring wires connected between the bobbin and the holder; and a magnetic driving unit driving the bobbin in the focus, track, or tilt direction with a focus coil, a tracking coil, and a tilt coil, wherein the magnetic driving unit comprises a circuit unit including winding starting ports for the focus coil, tracking coil, and tilt coil, and a common ground port at which winding end ports for the focus coil, tracking coil, and tilt coil are grounded, and the circuit unit applies a voltage to the tracking coil, tracking coil, and tilt coil. In the four-axial driving actuator for an optical pickup, the bobbin and the holder are connected with only four wires serving as electric wires, so that moving characteristics of the bobbin are improved and the assembly time is reduced. ## Claims ### Claim 1 A four-axial driving actuator for an optical pickup, comprising: a base; a holder fixed on the base; a bobbin to which an objective lens is fixed; spring wires connected between the bobbin and the holder; and a magnetic driving unit driving the bobbin in the focus, track, or tilt direction with a focusing coil, a tracking coil, and a tilt coil, wherein the magnetic driving unit comprises a circuit unit including winding starting ports for the focusing coil, tracking coil, and tilt coil, and a common ground port at which winding end ports for the focusing coil, tracking coil, and tilt coil are grounded, and the circuit unit applies corresponding voltages to the focusing coil, tracking coil, and tilt coil. ### Claim 2 (depends on 1) The four-axial driving actuator of claim 1, wherein the magnetic driving unit further comprises: a first magnet and a second magnet, each facing a corresponding pair of first and second magnets, respectively, with the bobbin therebetween; an outer yoke which is mounted on the base and to which one of the first magnets is fixed; and an inner yoke mounted on the base facing said one of the first magnets to guide the bobbin, wherein the focusing coil is wound around an outer wall of the bobbin, the tracking coil is wound at the side walls of the bobbin facing the first magnets, and the tilt coil is wound at the side walls of the bobbin facing the second magnets. ### Claim 3 (depends on 2) The four-axial driving actuator of claim 2, wherein the circuit unit comprises: an input generator generating the corresponding voltage to be applied to the focusing coil, tracking coil, or tilt coil; and a filter removing a high-frequency noise component from the corresponding voltage applied from the input generator to supply a noise-free voltage to the focusing coil, tracking coil, or tilt coil. ### Claim 4 (depends on 3) The four-axial driving actuator of claim 3, further comprising a comparator between the input generator and the filter. ### Claim 5 (depends on 1) The four-axial driving actuator of claim 1, wherein the circuit unit comprises: an input generator generating the corresponding voltage to be applied to the focus coil, tracking coil, or tilt coil; and a filter removing a high-frequency noise component from the corresponding voltage applied from the input generator to supply a noise-free voltage to the focusing coil, tracking coil, or tilt coil. ### Claim 6 A driving actuator for an optical pickup, comprising: a base having first and second magnets and a holder; a bobbin having an objective lens, a focusing coil, a tracking coil and a tilt coil; wires connected between the bobbin and the holder; and a magnetic drive unit driving the bobbin by interacting with the first and second magnets, wherein the magnetic drive unit comprises a circuit unit applying corresponding voltages to a first end of the focusing coil, the tracking coil, and the tilt coil, and a common ground connected to a second end of each of the focusing coil, the tracking coil, and the tilt coil. ### Claim 7 (depends on 6) The driving actuator according to claim 6, wherein the circuit unit comprises an input generator applying the corresponding voltages to the focusing coil, the tracking coil and the tilt coil, and a filter that removes high-frequency noise from the voltages applied by the input generator. ### Claim 8 (depends on 6) The driving actuator according to claim 6, wherein the circuit unit comprises a first input generator applying a voltage to the focusing coil, a second input generator applying a voltage to the tracking coil, and a third input generator applying a voltage to the tilt coil. ### Claim 9 (depends on 6) The driving actuator according to claim 6, further comprising: a focusing coil winding starting port; a tracking coil wind starting port; a tilt winding starting port; and a winding end port; wherein the focusing coil winding starting port and the tracking coil starting port are positioned on one side of the bobbin and separate from each other and the tilt winding starting port and winding end port are positioned on an opposite side of the bobbin and spaced apart from each other, the winding end port receiving and connecting second ends of the focusing coil, tracking coil and tilt coil. ### Claim 10 (depends on 9) The driving actuator according to claim 9, wherein the focusing coil is wrapped around the side of the bobbin. ### Claim 11 (depends on 10) The driving actuator according to claim 10, wherein portions of the tracking coil are positioned at opposite sides of the bobbin facing the first magnets and portions of the tilt coil are positioned at remaining opposite sides of the bobbin facing the second magnets.