Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tomohiko Sasano

Yasuhiro Tanaka

Michihiro Yamagata

Daisuke Ogata

Shusuke Ono

Kazutake Boku

Hiroshi Yamaguchi

Hiroyuki Asakura

Naohide Wakita

Sumio Terakawa

Hisanori Sugiura

Yoshikazu Sano

Tomoko Komatsu

Takafumi Hamano

Michiyo Ichikawa

Hiromitu Aoki

Disclosed is an optical head apparatus comprising: a light source; a collimating means of converting a beam of light emitted from the light source into a substantially parallel beam of light; a focusing means of focusing the light onto an information medium surface; a beam splitting means of splitting the beam of light modulated by the information medium; and a light receiving means of receiving the light modulated by the information medium, wherein a lens having a negative power and a lens having a positive power are arranged in this order as viewed from the collimating means side between the collimating means and the focusing means, and at least either one of the lenses is moved along an optical axis to correct spherical aberration occurring on the information medium surface, and wherein the distance from the lens having the positive power to the focusing means is set substantially equal to the focal length of the lens having the positive power.

Optical head apparatus and optical information recording and reproduction apparatus

An objective lens () for an optical disk, which focuses a light beam from a light source, is designed so that a third-order coma aberration generated when the objective lens is inclined at a unit angle is larger than a third-order coma aberration generated when the optical disk () is inclined at the unit angle, mounted on an actuator for inclining the objective lens according to an inclination amount of the optical disk, and used. With this structure, it is possible to obtain an objective lens for an optical disk that has a large numerical aperture and is easy to manufacture and assemble, and in which the third-order coma aberration generated when the optical disk surface is inclined owing to a warp or the like can be corrected by small inclination of the objective lens, so as to reduce a residual astigmatism, which is generated according to the inclination amount, after the correction.

Objective lens and optical head device

An objective lens for an optical disk including one lens and capable of satisfying an excellent focusing property on any of two kinds of optical disks each having a different thickness. The objective lens () is formed of a single lens having aspheric surfaces on both sides with the surface () at the side of the light source a rotationally symmetric aspheric surface. Furthermore, the surface at the side of the optical disk () of the objective lens () is divided into an inner circumference region () and an outer circumference region () and a surface () forming the difference in level of about 0.3 &#x3bc;m that is provided in parallel to the optical axis (in the direction of the optical axis) at the boundary between the inner circumference region () and the outer circumference region (). The spherical aberration is corrected by the inner circumference region () and outer circumference () of the objective lens () corresponding to the optical disks having a different thickness.

Objective lens for optical disk

A device for calculating diffraction efficiencies of a diffraction lens divided into a plurality of regions, each region comprising at least one grating ring, comprises a first memory for storing information about diffraction efficiencies of the regions; a second memory for storing information about weights corresponding to the regions; and a first processor for retrieving information from the first and the second memory, and calculating diffraction efficiencies of the entire diffraction lens using the formula Thus, the diffraction efficiency of the diffraction lens can be calculated easily.

Device for calculating diffraction efficiencies of a diffraction lens, lens with grating element, and optical system for reading

There are provided an organic electroluminescence element which is excellent in visibility and which can maintain a light emission performance with a high degree of efficiency, an image forming apparatus which is excellent in visibility and which can maintain a light emission performance with a high degree of efficiency, and a portable terminal unit which is lightweight and which has a long use life. The organic electroluminescence element incorporates at least, on a substrate, an anode for injecting holes, a luminous layer having a light emitting zone, a cathode for injecting electrons, wherein light radiated from the luminous layer is extracted through a surface opposed to the substrate, and an inverted V-like structure higher than the luminous layer is formed on at least a part of an element forming surface of the substrate.

Organic electroluminescence element and image forming apparatus or portable terminal unit using thereof

An objective lens for an optical disk including one lens and capable of satisfying an excellent focusing property on any of two kinds of optical disks each having a different thickness. The objective lens ( ) is formed of a single lens having aspheric surfaces on both sides with the surface ( ) at the side of the light source a rotationally symmetric aspheric surface. Furthermore, the surface at the side of the optical disk ( ) of the objective lens ( ) is divided into an inner circumference region ( ) and an outer circumference region ( ) and a surface ( ) forming the difference in level of about 0.3 &mgr;m that is provided in parallel to the optical axis (in the direction of the optical axis) at the boundary between the inner circumference region ( ) and the outer circumference region ( ). The spherical aberration is corrected by the inner circumference region ( ) and outer circumference ( ) of the objective lens ( ) corresponding to the optical disks having a different thickness.

OBJECTIVE FOR OPTICAL DISK, OPTICAL HEAD DEVICE AND OPTICAL INFORMATION RECORDING/REPRODUCING APPARATUS BOTH COMPRISING THE SAME, MOLD FOR FORMING LENS, METHOD FOR MACHINING MOLD FOR FORMING LENS, AND SHAPE MEASURING INSTRUMENT

An objective lens ( ) for an optical disk, which focuses a light beam from a light source, is designed so that a third-order coma aberration generated when the objective lens is inclined at a unit angle is larger than a third-order coma aberration generated when the optical disk ( ) is inclined at the unit angle, mounted on an actuator for inclining the objective lens according to an inclination amount of the optical disk, and used. With this structure, it is possible to obtain an objective lens for an optical disk that has a large numerical aperture and is easy to manufacture and assemble, and in which the third-order coma aberration generated when the optical disk surface is inclined owing to a warp or the like can be corrected by small inclination of the objective lens, so as to reduce a residual astigmatism, which is generated according to the inclination amount, after the correction.

A beam shaper is made up of a single lens whose both surfaces are toric surfaces. Assuming that directions where the beam divergence angle are larger and smaller in the far field from the semiconductor laser source are referred to as the vertical and horizontal directions, respectively, both of the toric surfaces have aspheric surfaces in a cross-section in the vertical direction, both of the toric surfaces have spherical surfaces in a cross-section in the horizontal direction, and both centers of curvature of the spherical surfaces are located substantially at a luminous point of the semiconductor laser source.

Beam shaper, and semiconductor laser source device and optical head using the beam shaper

In a lens array, a multiplicity of condenser lenses, each in a convex lens form, are arrayed in vertical and horizontal directions so as to correspond to pixel regions, respectively, and each condenser lens, when viewed from a direction perpendicular to a condenser lens-arrayed plane, takes a planar shape formed with a four straight sides along four sides of the pixel region and four circular arcs extending between the respective straight sides. A center of the four circular arcs substantially coincides with a center of the corresponding pixel region. This ensures an increase in area covered with the condenser lens in the pixel region, thereby causing more light rays to enter the condenser lens. In addition, a radius of curvature necessary for collecting can be obtained more easily. Consequently, light rays can be efficiently collected and guided to light receiving sections or the like provided in the pixel regions. Accordingly, sensitivity is improved when such a lens array is used in a solid-state imaging element, while luminance of a screen is improved when it is used in a panel display element. Besides, such a lens array is easily manufactured.

Lens array

An optical system for an optical disk, comprising a light source ( ), a collimating optical system ( ) for converting a luminous flux from the light source into parallel rays of light, and an object lens ( ) for condensing the parallel rays onto the information recording surface ( ) of an optical disk. The object lens consisting of two or three lenses and having a numerical aperture (NA) of at least 0.82 enables a high-density recording. Since a third-order astigmatism produced when the object lens is tilted 0.7 degree with respect to an optical axis is as small as up to 10 m lambda, a residual aberration, after a third-order comatic aberration produced when the optical disk is tilted due to warping or the like is corrected by tilting the optical lens, can be reduced. Therefore, a tilted optical disk still can ensure a satisfactory recording and/or reproducing quality.

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Osaka, Japan

Tomohiko Sasano