Abstract: A memory module is provided. A plurality of DRAMs is mounted on a PCB. At least one DRAM has an operating parameter different from other DRAMs according to a position where the at least one DRAM is mounted on the PCB.

Abstract: A memory module having an address mirroring function is provided. The memory module includes a register that allows mode registers of first memory chips of a first rank and mode registers of second memory chips of a second rank to be identically programmed in response to a mode register set (MRS) command during a rank-merged test mode. The register sets address signals, which are symmetrically connected to the first and second memory chips through through-via-holes (TVHs) or blind-via-holes (BVHs) of a printed circuit board, to be selectively mirrored.

Abstract: A memory module is provided. A plurality of DRAMs is mounted on a PCB. At least one DRAM has an operating parameter different from other DRAMs according to a position where the at least one DRAM is mounted on the PCB.

Abstract: A memory module is provided. A plurality of DRAMs is mounted on a PCB. At least one DRAM has an operating parameter different from other DRAMs according to a position where the at least one DRAM is mounted on the PCB.

Abstract: A memory module having an address minoring function is provided. The memory module includes a register that allows mode registers of first memory chips of a first rank and mode registers of second memory chips of a second rank to be identically programmed in response to a mode register set (MRS) command during a rank-merged test mode. The register sets address signals, which are symmetrically connected to the first and second memory chips through through-via-holes (TVHs) or blind-via-holes (BVHs) of a printed circuit board, to be selectively mirrored.

Abstract: A memory module is provided. A plurality of DRAMs is mounted on a PCB. At least one DRAM has an operating parameter different from other DRAMs according to a position where the at least one DRAM is mounted on the PCB.

Abstract: An optical pickup device includes a light source to emit light, an objective lens to focus the light on a recording medium to form a light spot, an optical path changer on an optical path between the light source and the objective lens to change the path of incident light, a chromatic aberration correction lens disposed on an optical path between the light source and the objective lens, and a photodetector to receive light which is reflected from the recording medium and is then incident thereon through the optical path changer. The chromatic aberration correction lens corrects a chromatic aberration occurring due to a change in the wavelength and/or due to an increase in a wavelength bandwidth of the light. The chromatic aberration correction lens includes at least two lenses such that a lens having a positive power and a lens having a negative power are adjacent to each other.

Abstract: An optical beam forming apparatus capable of forming a polarization of laser beam into an elliptic polarization includes a beam source to emit a semiconductor laser beam, a wave plate to receive the beam emitted from the beam source and to form an elliptic polarization, and a lens to focus the beam passed through the wave plate to form a beam spot on a disc.

Abstract: A semiconductor memory device capable of determining an operation mode by using states of data pins, and an operation mode determining method for the same are disclosed. The semiconductor memory device includes at least one MRS input pad, at least one data input pad, and an operation mode determining circuit. The operation mode determining circuit generates an operation mode determining signal, when an MRS command input through the MRS input pad corresponds to a predetermined MRS command and data signals input through the data input pad or pads include a predetermined combination. Accordingly, the efficiency in the manufacturing and producing processes may be improved by determining the operation mode of the semiconductor memory device in a module assembly process.

Abstract: An object lens for an optical disk may include an aspherical lens surface, and an aspherical equation, which may be applied to form the aspherical lens surface may include two 2nd order function terms. Accordingly, a lens, which has a high numerical aperture (NA) and also has a small flexure on a lens surface or aberration, is provided.

Abstract: A multi-mode electrostatic discharge (ESD) circuit for a semiconductor chip comprises first and second ESD diodes. In a first mode, a body voltage greater than a power source voltage of the semiconductor chip is applied to the first ESD diode and a body voltage less than a ground voltage of the semiconductor chip is applied to the second ESD diode. In a second mode, a body voltage substantially equal to the power source voltage of the semiconductor chip is applied to the body of the first ESD diode and a body voltage substantially equal to the ground voltage of the semiconductor chip is applied to the second ESD diode.

Abstract: An optical pickup actuator is provided. The actuator comprises a bobbin, on which one or more objective lenses are mounted for allowing light to be incident onto an optical information storage medium, and which is supported by a support member to be movable in relation to a base. The actuator also comprises a magnetic circuit for independently driving the bobbin in focusing and tilt directions.

Abstract: A memory module includes a first memory group including a plurality of memory devices, a second memory group including a less number of memory devices with respect to the memory devices in the first memory group, a register configured to provide a command/address signal to the first memory group and a delayed command/address signal to the second memory group, a first signal line configured to transfer the command/address signal to the first memory group, and a second signal line configured to transfer the delayed command/address signal to the second memory group.

Abstract: An optical pickup actuator comprises a lens holder having an object lens which focuses a laser beam onto an optical information storage medium mounted thereon. In the optical pickup actuator the lens holder is movably supported by a support member with respect to a base. The optical pickup actuator also comprises a magnetic circuit to drive the lens holder in a focusing direction and a tilt direction independently.

Abstract: An optical pickup actuator, including a lens holder movably installed on a base, and mounted with an objective lens to transmit an incident light to an optical information recording medium, and a magnetic circuit to independently drive the lens holder in a focusing direction, a tilting direction and a tracking direction, respectively.

Abstract: An optical pickup apparatus according to an embodiment of the present invention, comprises an optical unit for projecting a plurality of wavelengths of light, the light including a celadon light, toward a recording medium and receiving the light reflected from the recording medium to thereby detect an information signal and an error signal, and a compatible objective lens for focusing a light projected from the optical unit to thereby form an optical spot on a recording surface of the recording medium and applying at least three light having different wavelength ranges to be compatibly used for both the high-density and the low-density recording mediums. Accordingly, the optical pickup apparatus is capable of compatibly employing a high-density recording medium, which uses a celadon light and is slimmer than a digital versatile disc (DVD), and at least one low-density recording medium.

Abstract: A memory module, a memory unit, and a hub with a non-periodic clock and methods for using the same. An example memory module may include a phased locked loop, receiving an external, periodic clock and generating one or more internal periodic clocks and a plurality of memory units, receiving one of the internal periodic clocks or a non-periodic clock from an external source.

Abstract: An optical pickup actuator and a method of assembling the same is provided. The method of assembling the optical pickup actuator comprises the steps of providing a blade having at least one objective lens mounting area and an aberration correcting mechanism mounting area, arranging an objective lens in the objective lens mounting area, positioning an aberration correcting mechanism in the aberration correcting mechanism mounting area such that the central point of the aberration correcting mechanism coincides with the central point of the objective lens, tuning the aberration correction mechanism, and adhering the aberration correcting mechanism using an adhesive.

Abstract: A memory module test system including at least one memory module. The at least one memory module includes a first hub and a plurality of semiconductor memory devices. The system includes a tester for testing the at least one memory module. A second hub is located between the first hub and the tester. The second hub is for converting a memory command and memory data output from the tester into packet data and transmits the packet data to the first hub. The second hub converts the packet data output from the first hub into memory data and transmits the memory data to the tester.

Abstract: A memory module testing apparatus and method include a test slot adapted to receive a target memory module, wherein the target memory module includes a first memory unit to store information related to the target memory module. The memory module testing apparatus further includes a second memory unit adapted to store information related to a memory module, and a first switching unit adapted to selectively provide a driving signal to at least one of the first memory unit and the second memory unit.