Pioneer Corporation

Hirokatsu Nagatake

Akira Miura

Shinichi Takahashi

Masayuki Koyama

Ko Ishii

Makoto Kawamura

Mitsutoshi Sugano

Aki Yoshioka

Hitoshi Furuhata

Tomotaka Nishimura

An optical pickup which appropriately detects reflected light and return light reflected back from an information recording medium even if a laser light Bemitted from a light source varies in wavelength. The transmittances of a half mirror to the laser light Bemitted from the light source, and to the reflected light Bwr, Ber or the return light Brr reflected back from the information recording medium are preset according to a predetermined condition, i.e., Tpc(&#x3bb;c)/Tp(&#x3bb;)=(1&#x2212;Ts(&#x3bb;)/(1&#x2212;Tsc(&#x3bb;c))&#xd7;(Tsc(&#x3bb;c)/Ts(&#x3bb;)). Here, &#x3bb; is a predetermined wavelength emitted from a semiconductor laser as the light source, Ts(&#x3bb;) is a transmittance to the laser light Bwith a predetermined polarization, Tp(&#x3bb;) is a transmittance to the reflected light Bwr, Ber or the return light Brr reflected back from the information recording medium when the laser light Bwith the predetermined wavelength &#x3bb; is emitted, Tsc(&#x3bb;c) is a transmittance to the laser light Bwith a wavelength &#x3bb;c when the semiconductor laser varies in wavelength characteristic, and Tpc(&#x3bb;c) is a transmittance to the reflected light Bwr, Ber or the return light Brr reflected back from the information recording medium when the laser light Bwith the wavelength &#x3bb;c is emitted.

Optical pickup

An optical pickup apparatus and a laser diode chip which can simplify and miniaturize a construction of the apparatus is provided for using a plurality of laser beams of different wavelengths. The laser diode chip is a chip for the optical pickup apparatus in which a plurality of light emitting portions for emitting the laser beams of the different wavelengths in the same emitting direction are formed on a substrate. Light emitting points of the plurality of light emitting portions are located at positions which are different in the emitting direction.

Optical pickup apparatus and laser diode chip

An optical pickup apparatus which supports two wavelengths and is amenable to a reduction in size without employing a combining prism. The optical pickup apparatus employs a semiconductor laser device implemented in the form of a one-chip laser diode having two light sources for emitting a first laser beam and a second laser beam at a wavelength different from that of the first laser beam. A photodetector unit has a first detector section for receiving the first laser beam and a second detector section for receiving the second laser beam, and is set at positions at which the first and second laser beams follow return light paths of different lengths from an optical disc to the first and second detector sections.

Optical pickup apparatus for reading different types of recording media at different reading wavelengths

An optical pickup apparatus capable of reading information from recording media of different read wavelengths, includes a light-emitter having a first light source for emitting a first laser beam integrated with a second light source for emitting a second laser beam of a different wavelength from that of the first laser beam. The optical pickup apparatus includes a photodetector for receiving a beam reflected by each of the recording media and an optical system having a plurality of optical elements which form an optical path to guide the first and second laser beams to the recording media and which form an optical path for guiding the reflected beam to the photodetector and through which the first and second laser beams pass.

Optical pickup apparatus

An optical pickup apparatus includes a semiconductor laser device having a plurality of light emitting portions for emitting laser beams having different wavelengths on a substrate for emitting a laser beam from one of the plurality of light emitting portions in response to a light emitter selecting instruction in the same emitting direction. The laser beam emitted from the semiconductor laser device is converged by an objective lens and led to a recording surface of an optical disk, and the objective lens is moved to one of a plurality of different positions in a radial direction of the optical disk, corresponding to the selected light emitting portion.

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Tokorozawa, Japan

Hirokatsu Nagatake