摘要:
A solid-state image pickup device capable of taking more light into light receiving regions is provided. The solid-state image pickup device of the present invention includes: a photoelectric conversion unit having a plurality of light receiving regions that are two-dimensionally arrayed, the photoelectric conversion unit for photoelectrically converting light incident on each of the light receiving regions, and outputting an electric signal according to the intensity of the incident light; a lens unit comprising a plurality of converging lenses provided on an upper layer of the photoelectric conversion unit, each of the converging lens being provided corresponding to a set of continuous first to third light receiving regions; and a dispersing element provided between the photoelectric conversion unit and the lens unit, the dispersing element being formed of a medium whose refractive index varies periodically, and diffracting beams of a first wavelength band and of a third wavelength band, having been transmitted through the converging lens, and directing the beams onto the first light receiving region and the third light receiving region, and transmitting, without diffracting, a beam of a second wavelength band, having been transmitted through the converging lens, and directing the beam onto the second light receiving region.
摘要:
An objective lens element that can suppress occurrence of an aberration is disclosed. Sawtooth-like diffraction structures having different height and cycles (pitches) are provided on an inner part R21 and an outer part R22, respectively. A curved surface M211 extending at an intermediate level of recesses and projections of the sawtooth-like diffraction structure provided on the inner part R21, and a curved surface M212 extending at an intermediate level of recesses and projections of the sawtooth-like diffraction structure provided on the outer part R22 are smoothly connected to each other. Even when wavelength of the light source and/or the environmental temperature change, a phase shift does not occur between the inner part R21 and the outer part R22, and a decrease in diffraction efficiency and occurrence of an aberration can be suppressed.
摘要:
An optical element which has optical steps each providing a phase difference to transmitted light and has low light amount loss and a high efficiency is provided. The optical element includes a symmetry axis, a plurality of optically functional surfaces which are ring-shaped regions around the symmetry axis, and a plurality of wall regions connecting the optically functional surfaces to each other. The optically functional surfaces and the wall regions constitute the optical steps. On a cross-section taken by, as a cutting plane, a plane including the symmetry axis, the contour line of each wall region is substantially parallel to a light beam which is incident on the optically functional surface on the outer side and passes near the wall region. The maximum value of the angle between the symmetry axis and the light beam passing near the wall region is equal to or more than 25 degrees.
摘要:
An objective lens element which can obtain appropriate spot performance only by simple position adjustment, and an optical pickup device using the objective lens element are provided. In the objective lens element, an amount of a generated third-order astigmatism of a spot which is formed when symmetry axes of optically functional surfaces are located parallel to the normal line of a base plate and an incident light beam incident such that a central light beam thereof is tilted at 0.5 degree with respect to the normal line of the base plate is converged, is reduced to be less than an amount of a generated spherical aberration of a spot which is formed when the symmetry axes of the optically functional surface are located parallel to the normal line of the base plate and an incident light beam incident parallel to the normal line of the base plate is converged.
摘要:
A light-absorbing member has a substrate (101, 111) made of a material capable of absorbing light of which reflection is to be prevented, and an antireflection structure (102, 112, 303) having structural elements arranged on the surface of the curve in an array form at a period smaller than the wavelength of the light. The substrate having the shape of a curve viewed from a macroscopic viewpoint. The structural elements have a shape protruding or being recessed from a reference face corresponding to the curve of the substrate, and are arranged so that the straight lines connecting the reference face to the tips of the respective structural elements are nearly parallel to one another.
摘要:
An objective lens (1) 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 (2) 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.
摘要:
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.
摘要:
An optical pickup 1 includes a collimator lens 13 for changing the shape of a laser light by moving on the optical axis AX from a base point. An objective lens 15 is set so as to form a spot of which size, when the collimator lens 13 is located at the base point, is minimum at a point apart from the light source side surface of an information recording medium 20 by a distance of Lc defined by an expression (1): Lc=(L0+Ln)/2 (1), wherein Lc is named as a thickness to the designed center; L0 is a distance between the light source side surface of the information recoding medium and an information recording face located nearest to the light source side surface; and Ln is a distance between the light source side surface of the information recording medium and an information recording face located farthest from the light source side surface.
摘要:
An optical pickup (1) includes a light source (6) capable of emitting laser beams of various wavelengths and an objective optical system (2). The objective optical system (2) includes at least two wavefront conversion surfaces (13a) and (16a) and an objective lens (10). The at least two wavefront conversion surfaces (13a) and (16a) convert a wavefront of any laser beam entered therein into a different wavefront in response to the kind of an optical information recording medium (3) corresponding to the laser light. The objective lens (10) focuses the laser beam came out of the wavefront conversion surface (16a) on an optical information recording surface (3R). The optical pickup (1) satisfies the following condition for every wavelength of the corresponding laser beams: |SCMAX|
摘要:
An objective optical system 10 includes a diffraction plane 15 for separating a laser light beam into at least 0th-order diffracted light and 1st-order diffracted light. The objective optical system 10 is configured to focus the 0th-order diffracted light onto an information recording surface 22a of a first information recording medium 20a and the 1st-order diffracted light onto an information recording surface 22b of a second information recording medium 20b and meet the following conditional expression (1): η0>η1 (1) wherein η0 is the diffraction efficiency of the 0th-order diffracted light and η1 is the diffraction efficiency of the 1st-order diffracted light.