Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: A focal detecting means (35) of a controller (25) controls an actuator driver (38) to actuate an actuator (12) to vibrate an objective lens (3) in a direction along an optical axis. An output of a focus error signal from a signal generator (27) is checked by a signal detecting means (46) and presence of a workpiece is determined when the signal is detected. When the presence of the workpiece is detected, the focal detecting means (35) moves the objective lens (3) along the optical axis by the actuator (12) and a focus position is recognized with reference to a position signal from a position detecting means (49) together with the focus error signal, where the objective lens (3) is moved to the focus position for focusing.

Abstract: An operation for recording a recording signal onto a disk (1) is interrupted, when an amount of signal data stored in a buffer RAM (11) for temporarily storing the recording signal is less than an interruption setting value during performing of the recording operation. Moreover, when the amount of signal data stored in the buffer RAM (11) increases and indicates a resumption setting value, the signal recorded on the disk (1) before interruption is reproduced, and the recording operation is resumed based on the reproduced signal. Moreover, recording properties are detected by the signal reproduced before resumption of recording.

Abstract: The present invention provides an optical recording medium capable of detecting groove start signals and groove end signals with an inexpensive detection circuit and allowing quick, stable clock detection and tracking pull-in, which optical recording medium is constructed in such a way that the depth DG of the grooves satisfies DG/(?/N)<0.16, where ? is a wavelength of a light beam and N is an index of refraction of a substrate, and that the distance Ls between the groove edge and the pit closest thereto satisfies Ls>1.2 FWHM, where FWHM is a full width at half maximum of the light beam in the track direction.

Abstract: In a scanning apparatus, a scanning spot is moved along a path from one track to another track of the information carrier, the scanning spot is accelerated in a first stage of the movement and decelerating in a second stage of the movement. Initially during the movement a displacement of the scanning spot is derived from a first and a second position signal. The velocity of the scanning spot is estimated during movement along the path. After the estimated velocity of the scanning spot exceeds a first predetermined value during the first stage of the movement, the displacement of the scanning spot is derived from the first position signal and independent from the second position signal, during movement along the path. After the estimated velocity has decreased below a second predetermined value during the second stage of the movement, the displacement of the scanning spot is again derived from both the first and the second position signal, during movement along the path.

Abstract: A solid immersion mirror (SIM) type objective lens and an optical pickup employing the same. The objective lens has a first curved surface which condenses incident light and a second curved surface surrounding the first curved surface which diverges incident light. A second transmission surface disposed to face the first transmission surface has an area which transmits incident light and a first reflection surface surrounding the second transmission surface which reflects incident light. A second reflection surface which surrounds the second curved reflects incident light. The objective lens realizes an NA of 0.7 or more with a single lens; has a working distance enabling far field recording/reproducing; has a smaller blocking area than that of the conventional SIM; and generates a smaller amount of side lobe. Where the objective lens is adopted in an optical pickup device, generation of jitter during reproduction or cross erasure during recording is minimized.

Abstract: A first multiplier 251 multiplies a reproduced RF signal rf(t) by a DC component of an APC monitoring output signal m(t), which component is an output signal from an LPF 252, and then supplies a signal resulting from the multiplication to an arithmetic unit 255. A second multiplier 254 multiplies the reproduced RF signal rf(t) by a laser noise component of the APC monitoring output signal m(t), which component is an output signal from an HPF 253, and then supplies a signal resulting from the multiplication to the arithmetic unit 255. The arithmetic unit 255 subtracts the signal from the multiplier 254 from the signal from the multiplier 251 to thereby remove both an additive noise component and a modulated noise component of laser noise.

Abstract: An accelerometer includes a field emitter to generate an electron beam current and a medium. An effect is generated when the electron beam current bombards the medium. The magnitude of the effect is affected by a physical impact imparting an amount of energy to the accelerometer to cause a relative movement between the field emitter and the medium. The amount of energy imparted to the accelerometer by the physical impact is determined by measuring the magnitude of the effect. The accelerometer can be integrally implemented in a storage device.