Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Junichi Asada

Seiji Nishiwaki

Youichi Saitoh

Kazuo Momoo

Shinji Uchida

Kenji Nagashima

Yuichi Takahashi

Junji Nagaoka

Yoshiaki Komma

Fumitomo Yamasaki

Toshiyasu Tanaka

Osamu Kajino

Yoshinao Taketomi

Hiroaki Matsumiya

Noriaki Terahara

Takaaki Tomita

Kousei Sano

Keiichi Matsuzaki

Shoichi Ishihara

Kazuo Yokoyama

Kazuhiro Minami

Sadayoshi Hotta

Yoshihiro Matsuo

Hiroshi Watanabe

Yasushi Kobayashi

Kiyoko Ooshima

Fumiko Yokotani

Hiroshi Kayama

Hiroshi Shiroiwa

Tetsuo Kitagawa

The first, third, fourth, and seventh photosensors are disposed on one side with respect to the centerline, and the second, fifth, sixth, and eighth photosensors are disposed on another side with respect to the centerline. The first and seventh photosensors are positioned between the third and fourth photosensors in the direction parallel to the centerline. The second and eighth photosensors are positioned between the fifth and sixth photosensors in the direction parallel to the centerline. The first photosensor receives overlapped light of the 0th-order light with the +1st-order diffracted light, the second photosensor receives overlapped light of the 0th-order light with the &#x2212;1st-order diffracted light, each of the third to sixth photosensors receives the 0th-order light, and does not receive the +1st-order diffracted light and the &#x2212;1st-order diffracted light, and each of the seventh and eighth photosensors receives at least the 0th-order light.

Recorder and player apparatus stably keeping track of recording medium

A disclosed objective lens includes: a lens having an entrance surface and an emission surface; and an anti-reflection coat formed on the emission surface, wherein a transmittance T[%] of the anti-reflection coat when an incident angle of a first laser beam having a first wavelength &#x3bb;(390 nm&#x2266;&#x3bb;&#x2266;430 nm) is 0&#xb0;, and the transmittance T[%] of the anti-reflection coat when the incident angle of the first laser beam is 40&#xb0; satisfy 0.95&#x2266;T/T&#x2266;1.05, and a transmittance T[%] of the anti-reflection coat when an incident angle of a second laser beam having a second wavelength &#x3bb;(630 nm&#x2266;&#x3bb;&#x2266;680 nm) is 0&#xb0; and a transmittance T[%] of the anti-reflection coat when the incident angle of the second laser beam is 40&#xb0; satisfy 0.85&#x2266;T/T&#x2266;0.97.

Objective lens, optical head, optical disk device, and information processing device

An objective lens, an optical head, an optical disk apparatus and an information processing apparatus which can suppress deterioration of a focal spot caused by a drop in the diffraction efficiency. Inner and outer circumference areas converge a laser beam, out of laser beams having a wavelength &#x3bb;which are diffracted by the inner and outer circumference areas, on a first information recording medium; the inner circumference area and a mid-circumference area converge a laser beam, out of the laser beams having a wavelength &#x3bb;which are diffracted by the inner circumference area and the mid-circumference area, on a second information recording medium; and the diffraction efficiency of the laser beam having the wavelength &#x3bb;is greater than the diffraction efficiency of the laser beam having the wavelength &#x3bb;

Objective lens, optical head, optical disk apparatus, and information processing apparatus

Light emitted from a radiation light sourcepasses through a diffraction gratingand is separated into transmitted light a and +1st/&#x2212;1st order diffracted lights b, c. These lights are collected through an objective lenson tracks of an optical discin a partially overlapped state. Light reflected by the tracks passes through the objective lensand is incident upon light diverging means. Subsequently, light corresponding to the transmitted light 'a' diverges into two light beams that are respectively incident upon light detection regions A, A, light corresponding to the diffracted lights 'b' and &#x201c;c&#x201d; respectively diverges into two light beams that are respectively incident upon light detection regions B, B, and C, C. A tracking error signal associated with the tracks of the optical discis generated by combining signals detected in the light detection regions A, A, B, B, C, and C

Optical disc device

An optical disk device has an aperture of an objective lens in an incoming path of a beam from a semiconductor laser to an optical disk formed larger than an aperture in a return path from the optical disk or an aperture is varied in recording and in reproduction. This configuration improves recording/reproducing ability since light is focused on an optical disk with high numerical aperture. In addition, since reflected light from the optical disk is detected with low numerical aperture, margins for tilt and defocus are not reduced. Furthermore, since unnecessary signal components contained in the reflected light can be eliminated, a S/N (signal-to-noise ratio) of an information signal also increases. Thus, a high-performance optical disk device can be obtained. Alternatively, by varying the aperture of an objective lens in recording and in reproduction, an optical disk device in which recording density and recording quality are increased without deteriorating reproduction quality can be obtained.

Optical information processor and optical element

To implement light quantity monitoring with high frequency responsivity and correction of astigmatic differences of a semiconductor laser with a simple configuration with a fewer parts. Of the light beam output from a semiconductor laser light source, a peripheral beam component is entered by a light reflection elementinto an anterior light monitoring photodetectorformed in the vicinity of a semiconductor laser light source. Furthermore, the surface of the reflection sphere of the light reflection element is formed anamorphic, and thus condensed to an appropriate size on the photodetector without being focused, providing high frequency responsivity. Furthermore, the light reflection elementis placed inclined at a predetermined angle so as to cancel out astigmatic difference of the optical semiconductor laser light source. In addition, the photodetectoris placed in the direction so that a reflected lightis bent by an inclination of the light reflection element, reducing the amount of parallel displacement during adjustment of the light reflection element

Optical head apparatus

The present invention provides the beam-shaping device which includes a first surface on which is formed a first grating through which a beam of light emitted from a light source on an optical axis passes; and a second surface on which is formed a second grating through which the beam of light having passed through the first surface passes; wherein the first grating and the second grating are designed, so as to maintain, when the wavelength of the emitted beam of light varies, a prescribed relationship between (1) the displacement of the first virtual light emitting point, in the first meridian plane containing the optical axis, and (2) the displacement of the second virtual light emitting point, in the second meridian plane perpendicular to the first meridian plane containing the optical axis.

Beam-shaping device, optical disc device, and fabrication method of beam-shaping device

To implement light quantity monitoring with high frequency responsivity and correction of astigmatic differences of a semiconductor laser with a simple configuration with fewer parts. Of the output from a semiconductor laser light source, a peripheral component is entered by a light reflection element into an anterior light monitoring photodetector formed in the vicinity of a semiconductor laser light source. Furthermore, the surface of the reflection sphere of the light reflection element is anamorphic, and thus condensed to an appropriate size on the photodetector without being focused, providing high frequency responsivity. Furthermore, the light reflection element is inclined at a predetermined angle to cancel out astigmatic differences of the optical semiconductor laser light source. In addition, the photodetector is placed so that reflected light is bent by an inclination of the light reflection element, reducing the amount of parallel displacement during adjustment of the light reflection element.

An optical element that receives a first incident light and a second incident light through a main surface and allowing the first and second incident lights to be transmitted therethrough, the first and second incident lights being linearly polarized lights having substantially orthogonal polarizing directions and having different wavelengths &lgr;1 and &lgr;2 respectively, the optical element receiving a first reflected light and a second reflected light generated when the first and second incident lights are reflected from a reflector through the other face, and allowing the first and second reflected lights to be transmitted therethrough again, the optical element has a polarizing hologram that allows the first incident light, the second incident light, and the second reflected light to be transmitted therethrough upon receiving these lights and that diffracts the first reflected light upon receiving this light; and at least one wavelength plate that varies at least one of polarizing states of all of the first incident light and reflected light and polarizing states of all or part of the second incident light and reflected light.

Optical element, optical pickup, information recording and reproducing method, and polarizing hologram

Optical pickup

An exposure equipment which is simply configured and can expose fine cyclic patterns whose pitch is smaller than the wavelength of light source has the laser beam 2 (wavelength .lambda.) outgoing from the light source 1 reflected on the mirror 3a, 3b, guided to the beam expander optical system 4, and converged by a focusing lens 4a, passing through a pinhole 4c located on the focal plane of the focusing lens 4a, and converted into parallel beam 5 with the beam diameter expanded by a collimator lens 4b, wherein this parallel beam 5 vertically impinges on and penetrates a phase shifter 6 with recessed portion and protruded portion repeatedly formed on the outgoing surface side of the parallel flat plate configured with transparent material of refraction index n, and as a result, .+-. first order diffracted light is generated, and the .+-. first order diffracted lights interfere with one another on the sensitized film facing the phase shifter via a spacer 7 to form fine fringes, thereby exposing the sensitized film.

Exposure equipment

Growing community of inventors

Hyogo, Japan

Junichi Asada