Asahi Kogaku Kogyo Kabushiki Kaisha

Pentax Corporation

Hoya Corporation

Hitachi, Ltd.

Other

Pioneer Corporation

Nippon Hoso' Kyokai

Asahi Kogaku Kogyo Kaisha

Asahi Kogyo Kabusiki Kaisha

Koichi Maruyama

Shuichi Takeuchi

Daisuke Koreeda

Masahiro Oono

Makoto Iki

Makoto Iwaki

Masato Noguchi

Hitoshi Kimura

Yoshiyuki Tashiro

Suguru Takishima

Isao Okuda

Masahiko Sasaki

Junji Kamikubo

Takeshi Shimano

Hiroshi Nishikawa

Toshio Ueda

Satoru Tachihara

Toshiyuki Kase

Eiichi Yamazaki

Shigeru Nakamura

Kazuo Shigematsu

Takayuki Sensui

Moriyasu Shirayanagi

Kuniharu Osakabe

Tsuyoshi Itoh

Iwao Ogura

Toshiharu Takahashi

Takashi Yamanouchi

Hiroshi Kuboya

Hiroyuki Ishida

Teruaki Hiyamuta

Tamiya Aiyama

Takayuki Ito

Tsuyoshi Ishikawa

Akira Arimoto

Tetsuya Nakamura

Ryota Ogawa

Sachio Hasushita

Shuji Yoneyama

Toshio Nakagishi

Wataru Kubo

Hisashi Konno

Tunehiko Sonoda

Syunitirou Wakamiya

Tetsuya Abe

Hitoshi Tanaka

Takashi Iizuka

Hiroshi Yamamoto

Shinichi Suzuki

Isao Takahashi

Shigeo Kubota

Minoru Takeda

Moriyasu Kanai

Masato Hara

Yutaka Takakubo

Takashi Morita

Jun Hirakawa

Eijiroh Tada

Kunio Ando

Takashi Okuyama

Katsuhiro Koike

Hiroshi Suganuma

Takeshi Matsuki

Tsutomu Takeuchi

Hiroshi Yokomizo

Norimichi Takahashi

Tamihiro Miyoshi

Naohito Sasaki

Tetsuo Ariyoshi

Haruki Tokumaru

Syun'itirou Wakamiya

Ryoichi Hirota

Kenichi Hasegawa

Ryoto Ogawa

Kenzo Yamanaka

Kenji Shimizu

Satoshi Kawanishi

Sakae Kunitoh

Michio Nakamura

Toshihiro Tanaka

A method of designing an optical element to be used for an optical system in which each of a plurality of light beams having different design wavelengths passes through the optical element is provided. The method includes determining at least two types of optical path difference functions including first and second optical path difference functions in such a manner that proportion, brought by the first optical path difference function, between diffraction orders at which diffraction efficiencies of the plurality of light beams are maximized is different from proportion, brought by the second optical path difference function, between diffraction orders at which diffraction efficiencies of the plurality of light beams are maximized, and obtaining a shape defined by combining the at least two types of optical path difference functions so as to apply the obtained shape to at least one surface of surfaces of the optical element.

Optical element and objective lens through which a plurality of light beams having different design wavelengths pass

A mask blank is provided by forming a plurality of films, including at least a thin film to be a transfer pattern, on a board. At the time of patterning a resist film of the mask blank according to pattern data, film information to check with a pattern is obtained for each of a plurality of the films.

Mask fabrication supporting method, mask blank providing method, and mask blank dealing system

An imaging optical system, which includes an imaging lens group having at least one lens, and an image side prism that bends light which has passed through the imaging lens group toward an image pickup device arranged at a predetermined position, and wherein the image side prism includes a reflection surface which reflects, toward the image pickup device, incident light proceeding from the imaging lens group and an exit surface from which light reflected from the reflection surface emerges, and wherein the image side prism has a cut surface formed by cutting off a vertex portion between the reflection surface and the exit surface such that a whole normal light incident area within which normal light is incident on the reflection surface remains, and the cut surface is a non-diffusing surface.

Imaging optical system and imaging apparatus

Design method of optical element and optical element through which a plurality of light beams having different design wavelengths pass

There is provided an objective lens used for a plurality of types of optical discs having a front surface and a rear surface, each of which includes an inner region and an outer region. The outer region has a surface shape which suppresses a coma caused when a beam used for a first optical disc is incident thereon obliquely with respect to an optical axis of the objective lens. The inner region is configured such that, at a boundary position between the inner region and the outer region, the coma caused when a beam used for a second optical disc is incident on the inner region obliquely at a first angle with respect to the optical axis is less than the coma caused when the beam used for the second optical disc is incident on the outer region obliquely at the first angle with respect to the optical axis. Further, an inclination &#x3b8;of the inner region and an inclination &#x3b8;of the outer region of the rear surface satisfy a condition: &#x2212;2.5&#x3c;&#x3b8;&#x2212;&#x3b8;&#x3c;0.0 . . . (1).

Objective lens

There is provided an assembling method for expanding a maximum admissible astigmatism of objective lens which includes defining a maximum admissible astigmatism for the entire optical system, installing the collimator lens on the optical system to cause a predetermined amount of astigmatism lying within a range of up to the maximum admissible astigmatism by tilting the collimator lens from a condition where a point source of the semiconductor laser lies on an optical axis of the collimator lens, and installing the objective lens on the body case of the optical system to bring a total amount of astigmatism of the entire optical system to a level smaller than or equal to the maximum admissible astigmatism for the entire optical system by rotating the objective lens from a condition where the point source of the semiconductor laser and the center of the collimator lens lie on the optical axis of the objective lens.

Assembling method for optical system of optical pick-up

In an optical information recording/reproducing device which executes information reading or writing on multiple types of optical discs having different data densities by selectively using first through third light beams having first through third wavelengths, respectively, at least one side of an optical element is provided with a step structure including a plurality of concentric refracting surfaces and steps between them. The steps include first steps each giving a first optical path length difference specified by a first optical path difference function, second steps each giving a second optical path length difference specified by a second optical path difference function, and special steps each giving an optical path length difference obtained by the sum or difference of/between the first and second optical path length differences. Annular zone widths between adjacent steps are set at 10 times the first wavelength or more.

Optical information recording/reproducing device, optical element for the same, and design method of the same

An optical system of an optical pick-up is provided. The optical system includes an optical element including at least a phase shift surface among the surfaces thereof, and located closer to a light source than the objective lens. In this configuration, ttis satisfied, where trepresents a thickness of a cover layer of a first optical disc for which a first laser beam is employed, and ta thickness of a cover layer of a second optical disc for which a second laser beam, having a longer wavelength than the first laser beam, is employed. NANAis satisfied, where NArepresents a numerical aperture for the first optical disc, and NAthe numerical aperture for the second optical disc. The phase shift surface includes a first region that converges the first laser beam on a recording surface of the first optical disc, and the second laser beam on a recording surface of the second optical disc. The first region includes at least an annular zone structure having an annular zone group including a step that gives an additional optical path length to the first laser beam generally by two wavelengths, with respect to an inner refracting surface at a boundary between adjacent refracting surfaces, and a return step portion located at an outer position of the annular zone group.

Objective lens and optical system for optical pick-up

There is provided an optical disc drive for recordation/reproduction for three types of optical discs by selectively using one of three types of light beams. The optical disc drive comprises an objective lens. The objective lens has a step structure which gives an optical path length difference to an incident beam at each step. When the third laser beam passes through the objective lens, the objective lens produces normal diffraction order light converging to a recording surface of the third optical disc and undesired diffraction order light converging to a point deviating from the recording surface of the third optical disc. A distance from a point to which the normal diffraction order light converges to a point to which the undesired diffraction order light converges is larger than or equal to twice a pull-in range of a focus error signal obtained when the third optical disc is used.

Optical disc drive and objective lens for the same

An objective lens for an optical pick-up which is used to record data to and/or to reproduce data from at least three types of optical discs by selectively using one of at least three light beams having different wavelengths is provided. When thicknesses of a first, second and optical discs are represented by t, tand t, respectively, a relationship t&#x2266;t&#x3c;tis satisfied. When numerical apertures required for the first, second and third optical discs are represented by NA, NAand NA, respectively, a relationship NA&#x2267;NA&#x3e;NAis satisfied. The first, second and third light beams are incident on the objective lens as substantially collimated light beams, respectively. In this configuration, at least one of surfaces of the objective lens includes a first area for attaining the numerical aperture required for recording data to and/or reproducing data from the third optical disc, and a second area located outside the first area. The first area includes an inner area including an optical axis of the objective lens, and an outer area located outside the inner area. The outer area is configured to converge the third light beam on a data recording layer of the third optical disc with an amount of an aberration being substantially zero. The objective lens satisfies a condition: 0.75&#x3c;h/h&#x3c;0.87 . . . (1), where hrepresents an effective radius of the first area, and hrepresents an effective radius of the inner area.

Objective lens for optical pick-up

An objective lens, for an optical information read/write device that performs read/write operations on each of a plurality of optical discs using a corresponding one of three laser beams having first, second, and third wavelengths &#x3bb;1, &#x3bb;2, and &#x3bb;3 (nm) satisfying a relationship &#x3bb;1&#x3c;&#x3bb;2&#x3c;&#x3bb;3, respectively, includes a phase shift structure having a plurality of ring-shaped refractive surface zones into which at least one surface of the objective lens is concentrically divided. The objective lens is made of material with an Abbe number &#x3bd;d satisfying a condition 40&#x2266;&#x3bd;d&#x2266;80. The phase shift structure has a step between each couple of the adjacent refractive surface zones that gives an optical path difference to an incident laser beam, so that a condition 2N+1.00&#x3c;|&#x394;OPD/&#x3bb;1|&#x3c;2N+1.30 is satisfied, where &#x394;OPD represents the optical path difference (nm) that the step gives to the laser beam with the first wavelength, and N represents a non-negative integer.

Objective lens and optical information read/write device

There is provided an objective lens used for three types of optical discs including by selectively using one of three types of light beams. At least one of surfaces of the objective lens is provided with a first region converging the third light beam on a recoding surface of the third optical disc. The first region has a step structure configured to have concentric refractive surface zones and to give an optical path length difference to an incident beam at each step formed between adjacent refractive surface zones. The step structure is configured such that the optical path length difference given by each step is substantially equal to an odd multiple of a wavelength of a first light beam, and a value of differentiation of an optical path difference function defining the step structure crosses zero in a height ranging from 30% to 70% of an effective diameter of the first region.

An optical pickup has a light source for emitting a plurality of laser beams with different wavelengths; and an objective lens for focusing the laser beams emitted from the light source on recording surfaces of plural types of information recording media. A diffractive lens structure is provided in a light path of the laser beam, the structure including ring zone areas divided by a plurality of phase steps for correcting a wavefront aberration of the laser beam, a diameter of an outermost phase step of the diffractive lens structure is smaller than a second largest effective diameter of effective diameters required for reproduction of the plural types of information recording media.

Optical pickup, optical element, and information reproducing apparatus configured for use with any of plural types of recording media

Growing community of inventors

Tokyo, Japan

Koichi Maruyama