Sharp Kabushiki Kaisha Corporation

Katsushige Masui

Keiji Sakai

Kazuhiro Tsuchida

Tetsuo Ueyama

Toshiya Nagahama

Naotaka Otsuka

Yukio Kurata

Shinzoh Murakami

Takehiro Shiomoto

Masahiro Ikehara

Renzaburo Miki

Noboru Fujita

Hiroshige Hirajima

Takahide Ishiguro

Mototaka Taneya

Nobuyuki Miyauchi

Kazunori Matsubara

Masaru Ogawa

Takeshi Horiguchi

Hiroshi Chikugawa

Zenpei Tani

Osamu Hamaoka

Makoto Tsuji

Shigehiro Yamada

Satoru Fukumoto

Naotaka Ohtsuka

In a diffractive element, its grating pattern is so configured that a diffraction angle of a diffracted light beam of a light source that is subject to the first-order diffraction in a diffraction area is matched with an angle of a light beam passing through the diffractive area emitted from a light source and a light source position is matched with a light originating point of the light source that emits a light beam to be transmitted, and the center of light intensity distribution is matched with that of the light source passing through the diffractive element by inclining an optical axis of the light source. A position of the diffractive element is adjusted based on an electric current value generated when a reflected return path light beam of the light source is diffracted by the diffractive element and enters the light source.

Semiconductor laser device, optical pickup apparatus, and method of manufacturing semiconductor laser device

Provided is an optical pickup apparatus that can be made compact and is capable of producing stable push-pull signals. The optical pickup apparatus includes a light source, an objective lens, a diffraction element, a light-receiving element, and a control-driving section. The diffraction element receives light reflected from an optical recording medium. The light-receiving element receives light beams diffracted by the diffraction element. The light-receiving element has a plurality of light-receiving regions. The light-receiving region produces an output signal responsive to the quantity of the incident light beam. The control-driving section obtains differences among the output signals from a plurality of the light-receiving regions by calculation to derive a push-pull signal, and drives the objective lens under control on the basis of the push-pull signal.

Optical pickup apparatus

A lens-side grating diffracts, in a direction of an emitter-side grating, two laser beams passed through the lens-side grating from an optical disk side. The emitter-side grating substantially passes the laser beam having a longer wavelength than the other laser beam, and directs it to a desired region of the light receiving element. The emitter-side grating diffracts the laser beam having a shorter wavelength than the other laser beam to direct a +1st diffracted beam of the laser beam thus diffracted to the same light receiving region as a 0th diffracted beam of the other laser beam. Such a structure may be employed that a &#x2212;1st diffracted beam of the laser beam of the longer wavelength is directed to the same light receiving region as the 0th diffracted beam (passed beam) of the laser beam of the short wavelength.

Optical-integrated unit and optical pickup device used for reading and/or writing information from/onto an optical record medium

An object of the invention is to provide a splitter, a light emitter, and an optical pickup apparatus which can realize a stable track servo. Because of the structure of an optical system including an objective lens () and a hologram pattern (), even when the hologram pattern () is irradiated with a reflected light from one recording layer other than another recording layer in a focused state, first and second TES splitting portions () are not irradiated with the reflected light from the one recording layer, but the reflected light is led to an axis vicinity portion () only. Accordingly, light reception by first and second TES light receiving portions () is prevented, accurate track position information and deviation information can be positively acquired, and troubles such as the objective lens () being driven beyond a movable range can be eliminated.

Splitting element, light emitter, and optical pickup apparatus

To read information from a target information recording surface reliably by canceling DC offsets in tracking-signal detection signals is provided. In effecting tracking servo by 3-beam method, auxiliary light receiving domains D, D, D, Dare provided. The auxiliary light receiving domain receives images formed by the light returned from a different information recording surface from the one targeted for reading. Sub beams of &#xb1; first-order diffracted light enter the light receiving domains D, D, D, D. With respect to the diffraction direction of the hologram, the auxiliary light receiving domains D, D(D, D) are provided on both sides of the light receiving domain D(D). Since signals are computed as: D&#x2212;(D+D); and D&#x2212;(D+D) with the internal connection, DC offsets can be canceled in RES signals (D+D, D+D) used in the DPP method.

Optical pickup device using polarizing hologram element and hologram laser therefor

In this semiconductor laser device, a polarization hologram transmits an outgoing beam directed from a semiconductor laser chip to an optical disk as a forward beam without diffracting the beam, and diffracts a backward beam of the laser beam, which is a return beam of the forward beam that has been reflected by the optical disk, so that the backward beam is deflected from a direction directed toward the semiconductor laser chip part and further directed toward first, second photoreception parts. Therefore, optical loss on the forward way from the semiconductor laser chip to the optical disk can be reduced, and return light to the semiconductor laser chip can be suppressed, so that a high-power, high-sensitivity semiconductor laser device can be realized.

Semiconductor laser device and optical pickup device

An optical pickup can be provided, the optical pickup being capable of recording and playback of a plurality of optical disks having different specs by using light beams of different wavelengths, and further being suitable for integrating the semiconductor lasers and light receiving elements into a single package, by including: first and second semiconductor lasers adjacently disposed; a three-beam diffraction grating for generating three beams for tracking control; a second hologram element for diffracting light of the second semiconductor laser to guide it to a photosensor; a complex polarization beam splitter (PBS) for reflecting only light from the first semiconductor laser; and a first hologram element for diffracting light of the first semiconductor laser to guide it to the photosensor.

Optical pickup

It is an object of the invention to provide a holographic laser and an optical pickup, with which it is possible to read from and write to a plurality of types of optical disks with different read wavelengths, and to achieve a more compact apparatus. The holographic laser includes for example a package, two semiconductor laser elements and a photodiode for reading out signals accommodated within the package, a holographic element positioned proximate to or in close contact with the top of a glass window, and a wavelength separating element positioned proximate to or in close contact with the top of the holographic element. The holographic laser is integrally formed as a single component.

Holographic laser and optical pickup

Not only a semiconductor laser element and a photodetector but also a capacitor connected to the photodetector is housed in a package to thereby reduce the distance from the capacitor to the photodetector so that power source noise is efficiently suppressed by the capacitor and a power source noise suppression effect is improved.

Semiconductor laser device and method for producing the same

A semiconductor laser device includes a base, a semiconductor laser chip and a resin layer enclosing the laser chip. The base may have a monitor photodiode mounted thereon in the vicinity of the laser chip. The resin layer enclosing the laser chip or both of the laser chip and the monitor diode chip is made of a single synthetic resin having a thickness not greater than 500 .mu.m and also having a surface substantially parallel to an outwardly oriented beam emitting end face of the laser chip.

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Nara, Japan

Katsushige Masui