Abstract: A projection display satisfies formulas {(4FR?)/(W?TphR)}?0.015 and W??0.5, where: F is an F-number of a projection lens; W? is a diagonal size (inch number) of a light modulation element; ph is a pixel count in one side direction of the light modulation element; T is a throw ratio of the projection display (=a projection distance s/a distance L in the one side direction of a projected image on a projection plane); R is a radius of an exit pupil of the projection lens; I is an integrated light quantity obtained by, in a light quantity distribution in the exit pupil, radially integrating the light quantity up to the radius R; and I?(=I/2) is an integrated light quantity obtained by, in the light quantity distribution in the exit pupil, radially integrating the light quantity up to a predetermined radius R? about barycenter of the light quantity distribution.

Abstract: An image projection method includes: reflecting, by a concave mirror, light having transmitted through one or more lenses after forming an intermediate-focused image of the light; and projecting an image onto a projection plane through reflecting the light reflected by the concave mirror by a plane mirror that has an aspect ratio of 1.9 or more.

Abstract: An illumination device includes: a light source section including a laser light source; a first uniformization optical member receiving light from the light source section; a second uniformization optical member receiving light from the first uniformization optical member; an optical device disposed on an optical path of outgoing light from the light source section; and a drive section vibrating the optical device.

Abstract: A projection display satisfies formulas {(4FR?)/(W?TphR)}?0.015 and W??0.5, where: F is an F-number of a projection lens; W? is a diagonal size (inch number) of a light modulation element; ph is a pixel count in one side direction of the light modulation element; T is a throw ratio of the projection display (=a projection distance s/a distance L in the one side direction of a projected image on a projection plane); R is a radius of an exit pupil of the projection lens; I is an integrated light quantity obtained by, in a light quantity distribution in the exit pupil, radially integrating the light quantity up to the radius R; and I?(=I/2) is an integrated light quantity obtained by, in the light quantity distribution in the exit pupil, radially integrating the light quantity up to a predetermined radius R? about barycenter of the light quantity distribution.

Abstract: An illumination device includes: a light source section including a laser light source; an optical element disposed on an optical path of a laser light beam emitted from the laser light source, branching an optical path of an incident light beam incident thereon into a plurality of optical paths, and allowing branched light beams to be output therefrom; an optical member receiving the branched light beams that travel along the plurality of optical paths, and allowing illumination light to be output therefrom based on the branched light beams; and a driver section driving the optical element to allow phases of the branched light beams to be changed independently of one another.

Abstract: An illumination device includes: a light source section including a laser light source, and allowing a laser light beam emitted from the laser light source to be outputted intermittently at a predetermined frequency; an optical element through which the laser light beam passes; and a driver section changing a coherency of the laser light beam by driving the optical element at a predetermined drive frequency. Expressions (1) |2×f2?n1×f1|?20 or (2) |2×f2?n2×f1|?3, (3) f2?20 or (4) f2?3, and (5) |f2?n1×f1|?20 or (6) |f2?n3×f1|?3 are satisfied, where f1 denotes the frequency in Hz, f2 denotes a variation frequency of luminance in illumination light outputted from the optical element in Hz, the variation frequency being generated by the driving of the optical element, n1 denotes an arbitrary integer of 0 to 10 both inclusive, and n2 and n3 denote respective predetermined integers of 0 to 10 both inclusive.

Abstract: An illumination device includes a light source section including a laser light source, and intermittently emitting, at a predetermined frequency, laser light emitted from the laser light source, an optical element passing the laser light emitted intermittently from the light source section, and a drive section vibrating the optical element at a predetermined vibration frequency. An expression 1 or 2 below is satisfied, where f1 [Hz] denotes the frequency, f2 [Hz] denotes a variable frequency of luminance in illumination light emitted from the optical element as a result of vibration of the optical element, n1 denotes an arbitrary integer of 0 or larger and 10 or smaller, and n2 denotes a predetermined integer of 1 or larger.

Abstract: Provided is an objective lens used in an optical pickup that performs recording and/or reproducing of information signals on three different types of optical discs using different wavelengths. The objective lens is configured to collect light beams with the at least three wavelengths ?1, ?2, and ?3, which satisfy a relationship of ?1<?2<?3, on signal recording surfaces of compatible optical discs corresponding to the respective wavelengths. The objective lens includes: a diffractive portion that has a predetermined diffraction structure formed on an incident side surface. The diffractive portion has a first region that is provided in an innermost peripheral portion so as to diffract the light beams, a second region that is provided outside the first region so as to diffract the light beams, and a third region that is provided outside the second region.

Abstract: Provided is an objective lens for selectively focusing each of light beams having three wavelengths ?1, ?2, and ?3 on a signal recording surface of a corresponding optical disc, the wavelengths ?1, ?2, and ?3 satisfying at least a relationship ?1<?2<?3, the objective lens including a diffraction section disposed on an entry-side surface thereof, the diffraction section including a first region disposed in an innermost radius portion, a second region disposed outside the first region, and a third region disposed outside the second region, the first to third regions being formed so that an aperture of the light beams are appropriately limited, the first region including a staircase-like diffractive structure having a certain number of levels configured so that diffracted light of a predetermined order has the highest diffraction efficiency and optical-path-difference phase amounts for the levels of the diffractive structure has a certain relationship.

Abstract: A plastic objective lens is configured to collect a light beam with at least a wavelength ? on a recording layer of an optical disk and is used in an optical pickup for recording and/or reproducing an information signal by illuminating a light beam on the optical disk having one or a plurality of recording layers in an incident direction of the light beam.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: An optical pickup includes: a first emission unit emitting an optical beam with a first wavelength corresponding to a first optical disc; a second emission unit emitting an optical beam with a second wavelength, which is longer than the first wavelength, corresponding to a second optical disc different from the first optical disc; a third emission unit emitting an optical beam with a third wavelength, which is longer than the second wavelength, corresponding to a third optical disc different from the first and second optical discs; a condensing optical device condensing, on a signal recording surface of a corresponding optical disc, the optical beams emitted from the first to third emission units; and a diffraction unit provided in the condensing optical device, which is disposed on the optical path of the optical beams with the first to third wavelengths.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: Provided is an objective lens used in an optical pickup that performs recording and/or reproducing of information signals on three different types of optical discs using different wavelengths. The objective lens is configured to collect light beams with the at least three wavelengths ?1, ?2, and ?3, which satisfy a relationship of ?1<?2<?3, on signal recording surfaces of compatible optical discs corresponding to the respective wavelengths. The objective lens includes: a diffractive portion that has a predetermined diffraction structure formed on an incident side surface. The diffractive portion has a first region that is provided in an innermost peripheral portion so as to diffract the light beams, a second region that is provided outside the first region so as to diffract the light beams, and a third region that is provided outside the second region.

Abstract: Provided is an objective lens for selectively focusing each of light beams having three wavelengths ?1, ?2, and ?3 on a signal recording surface of a corresponding optical disc, the wavelengths ?1, ?2, and ?3 satisfying at least a relationship ?1<?2<?3, the objective lens including a diffraction section disposed on an entry-side surface thereof, the diffraction section including a first region disposed in an innermost radius portion, a second region disposed outside the first region, and a third region disposed outside the second region, the first to third regions being formed so that an aperture of the light beams are appropriately limited, the first region including a staircase-like diffractive structure having a certain number of levels configured so that diffracted light of a predetermined order has the highest diffraction efficiency and optical-path-difference phase amounts for the levels of the diffractive structure has a certain relationship.

Abstract: A plastic objective lens is configured to collect a light beam with at least a wavelength ? on a recording layer of an optical disk and is used in an optical pickup for recording and/or reproducing an information signal by illuminating a light beam on the optical disk having one or a plurality of recording layers in an incident direction of the light beam.

Abstract: An optical pickup includes: a first emission unit emitting an optical beam with a first wavelength corresponding to a first optical disc; a second emission unit emitting an optical beam with a second wavelength, which is longer than the first wavelength, corresponding to a second optical disc different from the first optical disc; a third emission unit emitting an optical beam with a third wavelength, which is longer than the second wavelength, corresponding to a third optical disc different from the first and second optical discs; a condensing optical device condensing, on a signal recording surface of a corresponding optical disc, the optical beams emitted from the first to third emission units; and a diffraction unit provided in the condensing optical device, which is disposed on the optical path of the optical beams with the first to third wavelengths.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.