Taiyo Yuden Co., Ltd.

Katsuhiro Oyama

Fuyuki Miyazawa

Hiroya Kakimoto

Isao Matsuda

Mitsuo Sekiguchi

Takaki Hamamoto

Yasuhito Hagiwara

Masato Ikeda

Yoshikazu Sato

Tetsuharu Kubo

Hiroshi Takahashi

Akira Yamanaka

Ryuichi Sunagawa

Mitsuo Ueno

Mutsuo Nakazawa

Daizo Yokoyama

Satoshi Takakuwa

Hiraya Kakimoto

In one aspect, a load cell includes an elastic body, first optical unit, second optical unit, detector, and computation unit. The first optical unit has a light source, a first diffraction grating on which light from the light source is incident, and a light-receiving unit. The first optical unit is fixed to a first end portion of the elastic body and arranged within a hollow portion of the elastic body. The second optical unit has a second diffraction grating on which diffracted light from the first diffraction grating is incident to generate interference light. The second optical unit is fixed to a second end portion of the elastic body and arranged within the hollow portion. The detector detects the interference light. The computation unit computes a relative displacement amount of the second diffraction grating relative to the first diffraction grating on the basis of a signal obtained by the detector.

Load cell having a computation unit which computes displacement amount of the diffraction grating

A displacement measurement device includes: a light source; a first diffraction grating and a second diffraction grating arranged along a path of light from the light source and movable relative to one another, the first and second diffraction gratings generating diffracted light; an optical sensor that detects interference light produced by interference between &#x2212;nth order diffracted light generated as a result of the second diffraction grating diffracting +nth order diffracted light from the first diffraction grating and +nth order diffracted light generated as a result of the second diffraction grating diffracting &#x2212;nth order diffracted light from the first diffraction grating, where n is a natural number greater than or equal to 1; and a calculation unit calculating, according to a signal from the optical sensor, a relative displacement between the first and second diffraction gratings in a direction orthogonal to an optical axis of the first and second diffraction gratings.

Displacement measurement device and displacement measurement method

An optical unit includes: a first diffraction grating where light from a light source enters; a second diffraction grating that generates interference light as a result of diffracted light rays emitted from the first diffraction grating entering the second diffraction grating; and an optical member including a pair of reflective surfaces that are parallel and opposite to each other, the optical member being configured such that the pair of reflective surfaces respectively reflect &#xb1;mth-order diffracted light rays that are diffracted light rays of a specific order among a plurality of orders of the diffracted light rays emitted from the first diffraction grating so as to guide the &#xb1;mth-order diffracted light rays to the second diffraction grating, where m is a natural number.

Optical unit and displacement measuring device

There is provided a displacement measurement apparatus including: a light source; a pair of diffraction gratings that light emitted from the light source enters, the pair of diffraction gratings opposing each other while being relatively movable along an optical axis; a first optical sensor that detects interference light obtained by diffracted light emitted from a diffraction grating device of each of the pair of diffraction gratings; a second optical sensor that detects non-interference light emitted from the pair of diffraction gratings; and a correction unit that corrects a signal obtained by the first optical sensor based on a signal obtained by the second optical sensor.

Displacement measurement apparatus and displacement measurement method

A technique for measuring displacement involves passing parallel laser light from a laser light source through a first diffraction grating to a semi-transparent semi-reflective mirror. A portion of the laser light is reflected as first reversed light, which passes through the first diffraction grating. The remainder of the parallel laser light proceeds to a total reflection mirror and is reflected as second reversed light that passes through the semi-transparent semi-reflective mirror and the first diffraction grating. The amount of refracted light of a predetermined order that is of the first and second reversed light and that results from the first diffraction grating is detected by a first optical sensor, and the amount of displacement is obtained from the interference band or a signal thereof corresponding to the amount of relative motion in the axial direction of the total reflection mirror with respect to the semi-transparent semi-reflective mirror.

Method and apparatus for measuring displacement

A displacement measurement device includes a first diffraction grating that generates first diffraction light of a prescribed order; a second diffraction grating movable relative to the first diffraction grating, the second diffraction grating dividing the zeroth-order light that has passed through the first diffraction grating into zeroth-order light and a second diffraction light of a prescribed order; and a first optical sensor that detects interfering light beams formed by the first diffraction light from the first diffraction grating and the second diffraction light from the second diffraction grating to determine an amount of a displacement of the second diffraction grating relative to the first diffraction grating.

Interferometric measurement of displacement in axial direction of a grating

There is proposed an optical disk recording method that can prevent degradation of recording quality due to occurrence of thermal interference, and an optical disk recording reproduction device used in this recording method. The recording method has a step of executing a test record on an output proofing area of the optical diskwhile a spot diameter of the recording laser beam is varied, and deriving the relationship between the spot diameter and a characteristic value representing recording quality, a step of deriving a permissible range of a variation amount of the spot diameter on the basis of the derived relationship between the spot diameter and the characteristic value representing the recording quality; a step of irradiating a record region of the optical disk with the recording laser beam to detect spherical aberration while executing recording; and a step of executing aberration correction, in case the spherical aberration occurs, such that a variation amount of the spot diameter falls into the derived permissible range.

Recording method for optical disk and optical disk recording reproduction device

To ensure a favorable recording characteristic for a write-once recording medium for a bluish-purple laser, an optical information recording apparatus includes ways to write power to form recording marks, a space forming power to form spaces, a pulse width of a cooling pulse and ways to record information onto the optical information recording medium according to the setting of the write power, the setting of the space forming power and the setting of the pulse width of the cooling pulse. At this time, the pulse width of the cooling pulse and a ratio whose numerator is the write power and whose denominator is the space forming power have a preferable region of the recording characteristic, and information is recorded onto the optical recording medium by using values in this range.

Optical information recording apparatus and method

In order to ensure a favorable recording characteristic for a write-once recording medium whose recording layer is made of an organic dye having an absorption spectrum at a wavelength &#x3bb;=405 nm, this optical information recording apparatus includes a unit to set a write power to form recording marks, a space forming power to form spaces and a pulse width of a cooling pulse, and a unit to record information onto the recording medium according to the setting. The pulse width of the cooling pulse and a ratio of the space recording power to the write power are determined from a favorable region in a plane whose one coordinate axis represents the ratio and whose other coordinate axis represents the pulse width of the cooling pulse.

Novel evaluation indexes are introduced to allow both a total evaluation of data recording and an evaluation of individual detection patterns. A data recording evaluation method includes a step of reproducing a result of data recording performed on an optical disk and identifying a predetermined detection pattern in a reproduction signal, a step of detecting a signal state of the reproduction signal associated with the predetermined detection pattern, and a first calculation step for calculating a first evaluation index value based on the detected signal state and a reference state identified from the predetermined detection pattern. When there is a plurality of predetermined detection patterns as described above, a second calculation step is further provided for calculating a second recording state evaluation index value using the first evaluation index value calculated from each of the predetermined detection patterns. Data recording can be properly evaluated using the first and second recording state evaluation index values.

Data recording evaluation method and optical disk recording and reproduction device

An optical information recording reproduction device is disclosed, in which aberration detection is stably performed, so that an excellent record grade can be achieved. An RF signal is subjected to differential operation along a time axis of the signal, the RF signal being obtained from reflected light including primary light situated in the periphery of a primary dark ring enclosing zero-order light in a central portion of a beam spot formed on a pit; pulse signal waveforms are represented in an absolute value form, the pulse signal waveforms being generated in correspondence with front and rear ends of the beam spot on the time axis; the pulse signal waveforms represented in the absolute value form are stored into a storage medium; the stored, two pulse signal waveforms are combined to generate a beam profile of the beam spot formed on an optical recording medium; and a beam spot diameter, spherical aberration, and coma aberration of a record laser beam are adjusted based on the beam profile.

Optical information recording reproduction device

It is an object of the present invention to improve a margin to meet good recording quality by conducting a realtime correction of a recording condition of a medium with different recording characteristics for inner and outer circumferences. To accomplish the object, control factors for power and a pulse width are independently detected and corrected using an mT pulse having a length of m'T as a pulse for power control and an nT pulse having a length of n&#x2032;T as a pulse for pulse width control; more specifically, power correction for mT pulse and pulse width correction for nT pulse are conducted in realtime, wherein a recording pulse stream including the mT pulse and nT pulse is irradiated onto a medium by a recording laser beam as well as pits and spaces formed by irradiation of the recording pulse stream are reproduced by a reproducing laser beam to detect the effects of power and pulse width variations independently.

Optical information recording device, optical information recording method, and signal processing circuit

An optical information recording reproduction device is disclosed which finds the correlation between the ratio of the minimum pit amplitude to the maximum pit amplitude of an RF signal obtained from the light reflected by the pits recorded on an optical disk in a tracking servo mode and spherical aberration in advance, and stores it. In recoding information on the optical disk, the optical information recording reproduction device calculates the ratio of the minimum pit amplitude to the maximum pit amplitude of the RF signal, and compares the calculation to the stored correlation, and feeds back to an aberration correction optical system and a driving mechanical system to correct the aberration into an aplanatic state.

An optical information recording apparatus corrects a recording condition for an optical medium having a difference in recording property between the inner and outer peripheries in real time. The optical information recording apparatus obtains an RF signal by using a playback sub beam and retrieves a portion of the RF signal corresponding to a constant output zone of a recording pulse using a gate signal. An average value of the retrieved signal is computed so as to set a reference position in real time. A difference between the top peak value of the retrieved signal and the average value and a difference between the bottom peak value of the retrieved signal and the average value are computed so as to obtain a &#x3b2; value in real time from the on-and-off RF signal affected by the recording pulse that turns on and off.

Optical information recording apparatus, optical information recording method, and signal processing circuit

Processing along one circular path is performed by irradiating a laser beam to a ceramic green sheet attached on an outer peripheral surface of a rotating drum, and the processing path is changed by moving at least one of the rotating drum and a beam irradiated position through a predetermined distance in the direction of drum centerline each time the processing on one circular path is completed. If the laser beam is intermittently irradiated to the ceramic green sheet, a matrix of through holes or concave portions can be easily formed in the ceramic green sheet.

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Tokyo, Japan

Katsuhiro Oyama