Abstract: A head-up display apparatus 200 includes: a projection optical system 30 that projects a virtual image; an environment monitor portion 72 as an object detection part that detects an object present in a detection region and detects a distance from the projection optical system 30 to the object as a target distance; an arrangement change apparatus 462 as a projection distance change part that periodically changes a projection distance of a virtual image from the projection optical system 30; and a main control apparatus 90 and a display control portion 18 as an image addition part that adds a related-information image as a virtual image by the projection optical system 30 to the detected object at timing when the target distance substantially matches the projection distance.

Abstract: An object of the present invention is to provide a virtual image display optical system that is capable of substantially simultaneously displaying virtual images at a plurality of distances even with a simple configuration, and an image display device using the virtual image display optical system. A virtual image display optical system (30) according to the present invention is provided with: a display element (11); a projection optical system (15) that enlarges an image formed on the display element (11); a diffusing screen (16) that has a diffusing function, and is positioned on the light emission side of the projection optical system (15); and a virtual image forming optical system (17) that converts an image on the diffusing screen (16) into a virtual image, wherein the virtual image display optical system (30) is further provided with a positioning changing device (62) that changes a position of the diffusing screen (16).

Abstract: A head-up display apparatus 200 includes: a projection optical system 30 that projects a virtual image; an environment monitor portion 72 as an object detection part that detects an object present in a detection region and detects a distance from the projection optical system 30 to the object as a target distance; an arrangement change apparatus 462 as a projection distance change part that periodically changes a projection distance of a virtual image from the projection optical system 30; and a main control apparatus 90 and a display control portion 18 as an image addition part that adds a related-information image as a virtual image by the projection optical system 30 to the detected object at timing when the target distance substantially matches the projection distance.

Abstract: An object of the present invention is to provide a virtual image display optical system that is capable of substantially simultaneously displaying virtual images at a plurality of distances even with a simple configuration, and an image display device using the virtual image display optical system. A virtual image display optical system (30) according to the present invention is provided with: a display element (11); a projection optical system (15) that enlarges an image formed on the display element (11); a diffusing screen (16) that has a diffusing function, and is positioned on the light emission side of the projection optical system (15); and a virtual image forming optical system (17) that converts an image on the diffusing screen (16) into a virtual image, wherein the virtual image display optical system (30) is further provided with a positioning changing device (62) that changes a position of the diffusing screen (16).

Abstract: An optical pickup apparatus includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical unit having a first optical path difference providing structure and a second optical path difference providing structure. Magnifications of the objective optical unit for the first-third light fluxes have almost same value. The first optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be one of under-correction and over-correction for all of the first light flux, the second light flux, and the third light flux. The second optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be the other of under-correction and over-correction of the spherical aberration only for the second light flux.

Abstract: An objective lens system for an optical pickup apparatus, includes in order from an object side: a first lens group having negative paraxial power P1 (mm?1); and a second lens group having positive paraxial power P2 (mm?1) for converging a light flux emitted from the first lens group on an information recording surface of an optical information recording medium.

Abstract: An optical pickup apparatus comprises a first light source for emitting a first light flux having first wavelength ?1 (430 nm>?1>380 nm), a second light source for emitting a second light flux having second wavelength ?2 (?2>?1), an objective optical system having phase structure thereon, and at least one moving optical element for guiding the light flux into the objective optical system, the moving optical element being moved in a direction parallel to an optical axis corresponding to the first light wavelength ?1 and the second light wavelength ?2, wherein the objective optical system has phase structure and satisfies M1=M2=0, where, M1 and M2 denote a first and second magnifications of the objective optical system for recording and/or reproducing the information on or from the first and second optical information media.

Abstract: An optical pickup apparatus for information recording and/or reproduction on different optical information recording media with compatibility among these media, the optical surface of a first objective lens and the optical surface of a second objective lens are formed only of a refractive surface. The second objective lens is used in common for the first light flux with a wavelength of ?1 and the second light flux with a wavelength of ?2, but in the case where the protective substrate t2 of the second optical information recording medium and the protective substrate t3 of the third optical information recording medium are the same, it is not necessary to take the difference in thickness of the protective substrate into consideration. Chromatic aberration based on the difference in wavelength between the first light flux and the second light flux can be corrected by displacing the second coupling lens.

Abstract: An objective lens system for an optical pickup apparatus, includes in order from an object side: a first lens group having negative paraxial power P1 (mm?1); and a second lens group having positive paraxial power P2 (mm?1) for converging a light flux emitted from the first lens group on an information recording surface of an optical information recording medium.

Abstract: An objective lens system for an optical pickup apparatus, includes in order from an object side: a first lens group having negative paraxial power P1 (mm?1); and a second lens group having positive paraxial power P2 (mm?1) for converging a light flux emitted from the first lens group on an information recording surface of an optical information recording medium.

Abstract: An optical pickup apparatus for information recording and/or reproduction on different optical information recording media with compatibility among these media, the optical surface of a first objective lens and the optical surface of a second objective lens are formed only of a refractive surface. The second objective lens is used in common for the first light flux with a wavelength of ?1 and the second light flux with a wavelength of ?2, but in the case where the protective substrate t2 of the second optical information recording medium and the protective substrate t3 of the third optical information recording medium are the same, it is not necessary to take the difference in thickness of the protective substrate into consideration. Chromatic aberration based on the difference in wavelength between the first light flux and the second light flux can be corrected by displacing the second coupling lens.

Abstract: In order to provide an optical pickup apparatus that has a relatively simple configuration and that can carry out recording and/or reproduction of information in a s compatible manner for different optical information storage medium, the optical surface of the first objective lens OBJ1 is formed only by a refracting surface, and hence it is possible to form it at a low cost even if it is made of glass. In addition, said first objective lens OBJ1 can be designed by optimizing it for the first light flux with the wavelength ?1 and the protective substrate t1 of said first optical disk OD1.

Abstract: The present invention has a beam shaping element for converting the light source 11 into a light flux whose emitting angle is almost equal and for projecting it, and a generation amount of the astigmatism generated by the temperature change is suppressed by a linear expansion of the beam shaping element.

Abstract: An objective optical element for use in an optical pickup apparatus first-third light sources emitting first-third light fluxes and a light converging optical system, includes a first optical path difference providing structure for providing an optical path difference which provides a substantial phase change to the third light flux and does not provide a substantial phase change to the first and second light fluxes; and a second optical path difference providing structure for providing an optical path difference to the first light flux, the second light flux and the third light flux, wherein the objective optical element converges the first-third light fluxes through the protective layers with the thicknesses t1-t3 onto an information recording surface of the first-third optical information media respectively.

Abstract: An optical pickup apparatus includes a diffractive optical element, and an objective lens that focuses a light beam of a first wavelength ?1, a light beam of a second wavelength ?2 and a light beam of a third wavelength ?3 on a first recording medium, a second recording medium, and a third recording medium, respectively, the wavelengths ?1, ?2, and ?3 being different from each other.

Abstract: A multi-focal objective lens for use in an optical pickup apparatus for recording and/or reproducing information using a first light flux with a wavelength ?1 on a first and second optical discs, includes a first optical surface including a first diffractive structure. The multi-focal objective lens converges a diffracted light flux with one of the m-th diffraction order and the n-th diffraction order on an information recording surface of the first optical disc for recording and/or reproducing information of the first optical disc, and converges a diffracted light flux with another of the m-th diffraction order and the n-th diffraction order on an information recording surface of the second optical disc for recording and/or reproducing information of the second optical disc.

Abstract: In a beam shaping device for converting the laser light emitted from a semiconductor laser light source from an elliptic beam to a circular beam, the light-entrance-side and light-exit-side surfaces of the beam shaping device both have a curvature only in the minor-axis direction of the cross section of the elliptic beam. Of the light-entrance-side and light-exit-side surfaces, one is a circular-arc cylindrical surface and the other is a non-circular-arc cylindrical surface. The beam shaping device fulfills prescribed conditions with respect to the center thickness, surface shapes, and/or other features.

Abstract: In a beam shaping device for converting the laser light emitted from a semiconductor laser light source from an elliptic beam to a circular beam, the light-entrance-side and light-exit-side surfaces of the beam shaping device both have a curvature only in the major-axis direction of the cross section of the elliptic beam. Of the light-entrance-side and light-exit-side surfaces, one is a circular-arc cylindrical surface and the other is a non-circular-arc cylindrical surface.

Abstract: An optical pickup apparatus includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical unit having a first optical path difference providing structure and a second optical path difference providing structure. Magnifications of the objective optical unit for the first-third light fluxes have almost same value. The first optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be one of under-correction and over-correction for all of the first light flux, the second light flux, and the third light flux. The second optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be the other of under-correction and over-correction of the spherical aberration only for the second light flux.

Abstract: In an optical pickup apparatus for reproducing and/or recording information from/onto four kinds of optical information recording mediums, an optical path of a light flux entering to a first objective optical element when using the first objective optical element and an optical path of a light flux entering to a second objective optical element when using a second objective optical element are arranged to be different so that a position of an incident light flux entering into the first objective optical element when using the first objective lens and a position of an incident light flux entering into the second objective optical element when using the second objective optical element are different in an orthogonal direction to an optical axis.