Abstract: An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.

Abstract: An optical system has an optical functional surface including a common region used for conducting information recording and/or reproducing for both of a first optical information recording medium and a second optical information recording medium. The common region comprises a refractive surface of an imaginary basic aspherical surface and a optical path difference providing structure in which plural ring-shapes zones are separated around the center of an optical axis and neighboring ring-shaped zones are displaced to each other in a direction of an optical axis so as to cause an optical path difference obtained by multiplying a predetermined wavelength ?s (?1<?s<?2) with almost an integer. The refractive surface of the imaginary basic aspherical surface is structured such that a spherical aberration becomes under on the first information recording medium and a spherical aberration becomes over on the second information recording medium.

Abstract: The present invention relates to an optical element for an optical pickup device, wherein the optical element is produced by molding a resin material, in which inorganic particles having a diameter of not more than 30 nm are dispersed in a plastic resin, an optical pickup device using the optical element, and a producing method of the optical element.

Abstract: A method of producing a lens that includes shifting a first die relative to a second die, and pressing an optical material shaped in a preliminary form between the first die and the second die so as to form a lens having a configuration corresponding to a hollow portion formed by the first die and the second die while shifting the first die relative to the second die. The produced lens includes an effective optical surface configured to converge a light flux. The effective optical surface includes a light entrance side, a light exit side, and an optical axis. The effective optical surface is a convex surface shaped such that when a maximum normal line angle is defined as an angle formed between the optical axis and a normal line at the outermost circumference of the effective optical surface, the maximum normal angle is 60° to 90°.

Abstract: A projection optical system that performs enlargement projection of an image on a display device surface formed of a plurality of pixels onto a screen surface, in which pixel shift by less than a pixel pitch is performed on the screen surface in a vertical direction, a horizontal direction, an oblique direction, or a vertical and horizontal directions, and in which conditional formulae (1) and (2) below are fulfilled over the entire image range: (1)|?RG|?0.5 d and (2)|?BG|?0.5 d, where d represents the amount of pixel shift (>0), ?RG represents lateral chromatic aberration in the direction of pixel shift of colored light R having a wavelength of 640 nm with respect to colored light G having a wavelength of 546 nm, and ?BG represents lateral chromatic aberration in the direction of pixel shift of colored light B having a wavelength of 450 nm with respect to the colored light G having a wavelength of 546 nm.

Abstract: The present invention provides a semiconductor light source module including: a semiconductor light source for emitting a light flux with a predefined wavelength; a SHG element for converting an incident light flux entering onto an incident end surface of the SHG element into an outgoing light flux having a different wavelength from the incident light flux; a light converging optical system for converging a light flux emitted from the semiconductor light source onto the incident end surface of the SHG element; a light receiving element for receiving a part of a light flux emitted from the SHG element; and a drive device for driving an optical element in the light converging optical system based on a light flux received by the light receiving element.

Abstract: A hybrid objective lens has a refractive lens and a diffractive optical element constructed by plural coaxial ring-shaped zones on at least one optical surface thereof. When n1, n2 and n3 each is a diffraction order of a diffracted ray having a maximum light amount among diffracted rays of each of first, second and third light flux having wavelength ?1, ?2 and ?3 when respective light flux comes to be incident into the diffractive structure respectively, the following formulas are satisfied: |n1|>|n2|, and |n1|>|n3|, and the hybrid objective lens converges a n1-th, n2-th and n3-th order diffracted ray of the first, second and third light flux onto an information recording plane of each of the first, second ant third optical information recording medium respectively so as to form an appropriate wavefront within respective prescribed necessary image side numerical apertures.

Abstract: An optical system has an optical functional surface including a common region used for conducting information recording and/or reproducing for both of a first optical information recording medium and a second optical information recording medium. The common region comprises a refractive surface of an imaginary basic aspherical surface and a optical path difference providing structure in which plural ring-shapes zones are separated around the center of an optical axis and neighboring ring-shaped zones are displaced to each other in a direction of an optical axis so as to cause an optical path difference obtained by multiplying a predetermined wavelength ?s (?1<?s<?2) with almost an integer. The refractive surface of the imaginary basic aspherical surface is structured such that a spherical aberration becomes under on the first information recording medium and a spherical aberration becomes over on the second information recording medium.

Abstract: A molding die for forming an optical element, comprises a base body; a film layer formed on the base body and having a thickness of 0.01 to 500 ?m; and a transferring surface formed on a surface of the film layer by a predetermined process and having a surface roughness Ra of 0.1 to 50 nm. The film layer is formed by an amorphous alloy having a supercooled liquid state containing 20 mol % or more of at least one atom of Pt, Ir, Au, Pd, Ru, Rh, Fe, Co, Ni, Zr, Al, Ti, Cu, W, Mo, Cr, B, and P and the transferring surface maintains the surface roughness after the transferring surface is heated to a temperature which is higher 50° C. higher than the glass transition temperature (Tg) of the optical element formed by the transferring surface and lower than the glass transition temperature of the amorphous alloy.

Abstract: An optical element used in a bidirectional optical communication module used for bidirectional optical fiber communication by a wavelength multiplex system, comprising a diffraction grating of binary structure prepared by molding, wherein a taper is formed at a portion of the diffraction grating where light entering the diffraction grating is intercepted by a convex part of the binary structure of the diffraction grating.

Abstract: A hybrid objective lens has a refractive lens and a diffractive optical element constructed by plural coaxial ring-shaped zones on at least one optical surface thereof. When n1, n2 and n3 each is a diffraction order of a diffracted ray having a maximum light amount among diffracted rays of each of first, second and third light flux having wavelength ?1, ?2 and ?3 when respective light flux comes to be incident into the diffractive structure respectively, the following formulas are satisfied: |n1|>|n2|, and |n1>|n3 |, and the hybrid objective lens converges a n1-th, n2-th and N3-th order diffracted ray of the first, second and third light flux onto an information recording plane of each of the first, second ant third optical information recording medium respectively so as to form an appropriate wavefront within respective prescribed necessary image side numerical apertures.

Abstract: An object lens unit for an optical pickup device is disclosed. The object lens unit includes a first optical element facing an optical information recording medium; a second optical element positioned on a light source side of the first optical element; and a frame in which the first optical element and the second optical element are fixed. The frame includes a first fitting portion and a second fitting portion, and has a prescribed clearance in a perpendicular direction to the optical axis between at least one of the first fitting portion of the frame and the first optical element, and the second fitting portion of the frame and the second optical element to adjust a position of at least one of the first optical element and the second optical element in a perpendicular direction to the optical axis. An optical pickup device including such object lens unit is also disclosed.

Abstract: An objective optical element of an optical pickup apparatus has a magnification m1 satisfying the following formula for a light flux of the wavelength ?1:?1/7?m1??1/25 and |m1 |<|M1, where M1 is an optical system magnification from the first light source to the first optical information recording medium for a light flux of the wavelength ?1. The objective optical element comprises a common region and an exclusive region. The exclusive region includes an exclusive diffractive structure having a function to suppress an increase of spherical aberration due to a raise of atmospheric temperature. A light flux of a wavelength ?2. having passed through the exclusive diffractive structure intersects with the optical axis at a position different from the position of the converged light spot formed on the information recording plane of the second optical information recording medium.

Abstract: An objective optical element of an optical pickup apparatus has a magnification m1 satisfying the following formula for a light flux of the wavelength ?1: ? 1/7?m1?? 1/25 and |m1|<|M1, where M1 is an optical system magnification from the first light source to the first optical information recording medium for a light flux of the wavelength ?1. The objective optical element comprises a common region and an exclusive region. The exclusive region includes an exclusive diffractive structure having a function to suppress an increase of spherical aberration due to a raise of atmospheric temperature. A light flux of a wavelength ?2 having passed through the exclusive diffractive structure intersects with the optical axis at a position different from the position of the converged light spot formed on the information recording plane of the second optical information recording medium.

Abstract: An object lens unit for an optical pickup device is disclosed. The object lens unit includes a first optical element positioned facing an optical information recording medium; a second optical element positioned on a light source side of the first optical element; and a frame in which the first optical element and the second optical element are fixed. The frame includes a first fitting portion and a second fitting portion, and has a prescribed clearance in a perpendicular direction to the optical axis between at least one of the first fitting portion of the frame and the first optical element, and the second fitting portion of the frame and the second optical element to adjust a position of at least one of the first optical element and the second optical element in a perpendicular direction to the optical axis. An optical pickup device including such object lens unit is also disclosed.

Abstract: A hybrid objective lens has a refractive lens and a diffractive optical element constructed by plural coaxial ring-shaped zones on at least one optical surface thereof. When n1, n2 and n3 each is a diffraction order of a diffracted ray having a maximum light amount among diffracted rays of each of first, second and third light flux having wavelength ?1, ?2 and ?3 when respective light flux comes to be incident into the diffractive structure respectively, the following formulas are satisfied: |n1|>|n2|, and |n1>|n3|, and the hybrid objective lens converges a n1-th, n2-th and n3-th order diffracted ray of the first, second and third light flux onto an information recording plane of each of the first, second ant third optical information recording medium respectively so as to form an appropriate wavefront within respective prescribed necessary image side numerical apertures.

Abstract: An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.

Abstract: An optical communication module includes a first light-receiving element with a receiving surface in which a light flux with a wavelength ?1 emitted from an end surface of an optical fiber enters; a light-emitting element for emitting a light flux with a wavelength ?2; and a first optical element arranged between the first light-receiving element and the light-emitting element, and the end surface of the optical fiber. The first optical element includes a first optical surface with a positive refractive power and a second optical surface having a diffractive structure. One of the first optical surface and the second optical surface is divided into at least a first optical functional surface and a second optical functional surface through a step difference.

Abstract: A hybrid objective lens has a refractive lens and a diffractive optical element constructed by plural coaxial ring-shaped zones on at least one optical surface thereof. When n1, n2 and n3 each is a diffraction order of a diffracted ray having a maximum light amount among diffracted rays of each of first, second and third light flux having wavelength ?1, ?2 and ?3 when respective light flux comes to be incident into the diffractive structure respectively, the following formulas are satisfied: |n1|>|n2|, and |n1|>|n3|, and the hybrid objective lens converges a n1-th, n2-th and n3-th order diffracted ray of the first, second and third light flux onto an information recording plane of each of the first, second ant third optical information recording medium respectively so as to form an appropriate wavefront within respective prescribed necessary image side numerical apertures.

Abstract: An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.