Pioneer Corporation

Pioneer Electronic Corporation

Akira Miura

Shinichi Takahashi

Hirokatsu Nagatake

Masayuki Koyama

Ko Ishii

Makoto Kawamura

Mitsutoshi Sugano

Aki Yoshioka

Taichi Akiba

Akihiro Tachibana

Toshihiko Kurihara

Hitoshi Furuhata

Tomotaka Nishimura

Yoshiharu Suzuki

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

A monolithic double-wavelength semiconductor laser diode is provided in a DVD/CD compatible player to suppress deterioration in the optical characteristics of a reading light spot. A laser diode is a monolithic element which has two light emitting points on a single substrate for emitting two different laser beams having different wavelengths with each other. A central line of a main laser beam for use in reproducing DVDs is positioned closer to the optical axis Y of an optical system than a central line of a laser beam for use in reproducing CDs. In another arrangement, the central line of a main laser beam for use in reproducing DVDs is positioned so as to be coincident with the optical axis Y of the optical system.

Optical pickup for CD/DVD compatible player

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

The optical pickup apparatus uses a semiconductor laser element integrated a first light emission source for emitting a first laser beam with a second light emission source for emitting a second laser beam, of which wavelength is different from that of the first laser beam. The optical pickup apparatus is constructed so that a first half mirror functional surface and a second half mirror functional surface are provided in a beam splitter to match an optical path in which the first laser beam passes through the first half mirror functional surface of the beam splitter and then is reflected at the second half mirror functional surface and again is emitted from the first half mirror functional surface to be directed toward a bifocal lens with an optical path in which the second laser beam is reflected at the first half mirror functional surface to be directed toward the bifocal lens

Optical pickup apparatus that emits two light beams having two different wavelengths

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.

An optical pickup device is provided with a focus error signal generating means which is adapted to calculate a first output sum signal obtained by adding together an output signal fed front one portion of the second light receiving means and an output signal fed from one portion of the third light receiving means, and to calculate a second output sum signal obtained by adding together an output signal fed from the other portion of the second light receiving leans and an output signal fed from the other portion of the third light receiving means, so as to calculate a difference between the first output sum signal and the second output sum signal, thereby producing a focus error signal.

Optical pickup device

A multiple focal light beam generating device is provided with a multiple focal mirror device, to which a light beam is incident from a front side thereof. The device has a plurality of mirror surfaces arranged in serial to the incident light beam such that at least one mirror surface other than a mirror surface disposed farthest from the front side comprises a half mirror surface, for reflecting the incident light beam respectively at each of the mirror surfaces into directions different from each other as a plurality of partial light beams; and a light condensing device, to which the partial light beams are inputted from the multiple focal mirror device, for respectively condensing the partial light beams such that positions of maximally condensed points of the partial light beams are different from each other.

Reflective light beam focusing device with multiple focal points

An optical pickup device using a polarizing optics system is characterized in that the polarization beam splitter comprises a polarizing film having optical properties of transmittance and reflectivity satisfying the following formulas (1) and (2):

An optical pickup apparatus for an information reproducing apparatus is adapted to reproduce one of at least first and second type optical record media which is loaded on the information reproducing apparatus. The first and second type optical record media have distances from surfaces to information record planes different from each other. The optical pickup apparatus is provided with: a light emission device for emitting a reading light; an objective lens for focusing the emitted reading light onto the information record plane of the loaded one of the first and second type optical record media such that a focus condition of the focused reading light is optimum with respect to the first type optical record medium; a correction device for correcting a spherical aberration of the focused reading light with respect to the second type optical record medium due to a difference in the distances from the surfaces to the information record planes between the first and second type optical record media when the second type optical record medium is loaded; and a light receiving device for receiving a reflection light of the focused reading light from the information record plane of the loaded one of the first and second optical record media.

Optical pickup apparatus and identification apparatus for identifying

A multiple focal lens is provided with: a diffraction element having a light incident surface and a light outgoing surface for diffracting a light beam incident from the external to the light incident surface and generating a plurality of diffraction light beams from the light outgoing surface; a light condense element for condensing the generated diffraction light beams respectively onto a plurality of focal points different in position from each other; and a main body for holding said diffraction element and said light condense element. A central axis of said diffraction element and a central axis of said light condense element are offset to each other such that one optical path of one reflection light, which is used for reproducing information, among a plurality of reflection lights of the condensed diffraction light beams reflected from an information record medium on which the information to be reproduced is recorded, and the other optical paths of the other reflection lights among the plurality of reflection lights are offset to each other.

Growing community of inventors

Tokorozawa, Japan

Akira Miura