Abstract: There is provided a diffraction grating including a convex portion and a concave portion which are used for lights having different wavelengths ?1, ?2 and ?3 and are alternately disposed on at least one surface of a substrate with a predetermined pitch. An average refractive index of the convex portion is smaller than an average refractive index of the concave portion. A phase difference in the lights having the wavelength ?1 which transmit the convex portion and the concave portion and a phase difference in the lights having the wavelength ?2 which transmit the convex portion and the concave portion are both substantially the integral multiple of 2?, and a phase difference in the lights having the wavelength ?3 which transmit the convex portion and the concave portion is substantially the non-integral multiple of 2?.

Abstract: A cosmetic composition comprising a polysiloxane copolymer comprising a repeating unit (A) having at least one anionic group, a repeating unit (B) having at least one linear or branched alkyl group having 8 to 64 carbon atoms, and a polysiloxane repeating unit (D), said repeating units (A), (B), and (D) being bonded with one another via diisocyanate residue represented by the following formula (1) wherein X is a divalent hydrocarbon group selected from the group consisting of aromatic hydrocarbon groups, aliphatic hydrocarbon groups, and alicyclic hydrocarbon groups. Cosmetics comprising the composition maintains their effects for a prolonged period of time.

Abstract: The present invention provides a wavelength-selective diffraction element, configured such that light having a plurality of wavelengths are incident thereon as incident light, which is provided with: a transparent substrate; a concavo-convex part, formed on the transparent substrate such that concave portions and convex portions are cyclically extended in one direction, and comprised of a first material which is optically isotropic; and a filling part, filling at least the concave portions and comprised of a second material which is optically isotropic. The first material and the second material have no absorbance with respect to the wavelengths of the incident light. The first material and the second material have an identical refractive index with respect to light having a first wavelength which is at least one of the wavelengths of the incident light.

Abstract: A polarizing diffraction element having a wavelength selectivity which functions as a polarizing diffraction element at a wavelength ?1, and which does not function as a diffraction grating not depending on incident polarization state and shows high transmittance at a wavelength ?2, and an optical head device employing the element, are provided. The polarizing diffraction element selectively diffracts or transmits incident light having two different wavelengths each containing a first circularly polarized light and a second circularly polarized light having a rotation opposite from the rotation of the first circularly polarized light, depending on wavelength and polarization state of the incident light. Then, a reflective wavelength region for at least the first circularly incident light, does not contain said two incident wavelengths.

Abstract: The present application relates to a liquid crystal lens element and an optical head device, in particular order, to a liquid crystal lens capable of switching the focal length among a plurality of different focal lengths according to switching of applied voltage among a plurality of applied voltages, and an optical head device employing the liquid crystal lens, for writing and/or reading an information to/from an optical recording medium.

Abstract: A phase correction element comprising a first phase correction layer formed in a region of numerical aperture NA2, and a first phase plate; the first phase correction layer comprising a concavo-convex portion having a rotational symmetry with respect to the optical axis of incident light and having a cross-sectional shape of a saw-tooth-form or a saw-tooth-form whose convex portions are each approximated by a step form; the first phase plate generating a birefringent phase difference of about an odd number times of ?/2 for linearly polarized light of ?1; and the phase correction element that does change a transmitted wavefront of ?1 and changing a transmitted wavefront of the ?2 or transmitted wavefront of both wavelengths of ?2 and ?3 when three types of incident light at ?1=410 nm, ?2=650 nm and ?3=780 nm respectively, are incident.

Abstract: The present invention provides a phase correction element which can be used for recording and/or reproducing an information of three types of optical disks for HD, DVD and CD by employing a single objective lens for HD, and an optical head device.

Abstract: A polarized diffractive filter contains cyclic concave/convex portions formed as a diffractive grating on a transparent substrate. The concave portions are filled with an optical material. At least one member selected from the group consisting of i) a material constituting the concave/convex portions, and ii) the optical material filled in the concave portions contains a liquid crystal material. The diffractive grating contains an isotropic material, the isotropic material having a refractive index outside a range from an extraordinary index to an ordinary index of the liquid crystal material. The polarized diffractive filter is capable of receiving light having at least two different peak wavelengths so as to shield light of at least one of the peak wavelengths by diffraction and to transmit the light of the other peak wavelengths.

Abstract: An optical rotating plate has an optical rotating material layer. A phase plate is provided on a first surface side of the optical rotating plate and has at least one birefringent material layer. The first surface side is disposed toward an emitting side of an optical path, thereby giving different phase differences to a first linearly polarized light group containing at least a linearly polarized light having a first wavelength and a second linearly polarized light group containing at least a linearly polarized light having a second wavelength which is different from the first wavelength.

Abstract: A phase plate having a reduced size and a reduced weight and having accurately parted regions while it has the same function as a conventional two-parted optical rotation plate and an optical data recording/reproducing device capable of stably recording and reproducing are presented. A phase plate P1 comprising a polymer liquid crystal film 2 held between transparent substrates i, 4, wherein the polymer liquid crystal film 2 is parted spatially in the region into which an incident light enters, so that the light transmitting the phase plate assumes a different state of polarization depending on an aligning direction of the molecules of the polymer liquid crystal film 2. The phase plate is located as a two-parted optical rotation plate in an optical data recording/reproducing device.

Abstract: In order to provide a wavelength-selective light-shielding element capable of blocking circularly-polarized light beams rotating in a specific direction among light beams whose wavelengths falling in a specific range, a light-shielding region is provided in a portion of a transparent substrate, wherein the light-shielding region permits passage of first circularly-polarized light rotating in a first direction regardless of a wavelength of the first circularly-polarized light and blocks second circularly-polarized light beams whose wavelengths falling within a predetermined range, among second circularly-polarized light beams rotating in the second direction, to thus permit passage of the second circularly-polarized light beams falling outside the predetermined range.

Abstract: To provide optical elements such as a phase plate suitably used in a broadband range and a polarizing diffraction element excellent in diffraction efficiency, a polymerizable liquid crystal composition to be used for them, and an optical head device using them.

Abstract: The present invention provides a wavelength-selective diffraction element, configured such that light having a plurality of wavelengths are incident thereon as incident light, which is provided with: a transparent substrate; a concavo-convex part, formed on the transparent substrate such that concave portions and convex portions are cyclically extended in one direction, and comprised of a first material which is optically isotropic; and a filling part, filling at least the concave portions and comprised of a second material which is optically isotropic. The first material and the second material have no absorbance with respect to the wavelengths of the incident light. The first material and the second material have an identical refractive index with respect to light having a first wavelength which is at least one of the wavelengths of the incident light.

Abstract: A diffraction element having concave/convex-like diffraction gratings in its two surfaces from which at least two separated light beams can be taken in the same direction without changing largely the propagating direction of diffracted light even if the temperature of the operating environment changes. A diffraction grating having a concave/convex shape in cross-section is formed in the incoming-side surface of the transparent substrate and two diffraction gratings of concave/convex shape in cross-section are formed in the outgoing-side surface wherein the grating pitch of the first one is made equal to the grating pitch of one of the second ones. In addition, a reflection type diffraction element exhibiting a good wavelength dependence of diffraction efficiency without being dependent largely on the direction of polarization of an incoming light is provided.

Abstract: A diffraction element having concave/convex-like diffraction gratings in its two surfaces from which at least two separated light beams can be taken in the same direction without changing largely the propagating direction of diffracted light even if the temperature of the operating environment changes. A diffraction grating having a concave/convex shape in cross-section is formed in the incoming-side surface of the transparent substrate and two diffraction gratings of concave/convex shape in cross-section are formed in the outgoing-side surface wherein the grating pitch of the first one is made equal to the grating pitch of one of the second ones. In addition, a reflection type diffraction element exhibiting a good wavelength dependence of diffraction efficiency without being dependent largely on the direction of polarization of an incoming light is provided.

Abstract: A liquid crystal lens element having a lens function is provided, which is small sized without having moving part, and which can stably carry out correction of spherical aberration containing a power component corresponding to focal point change of incident light.

Abstract: To provide optical elements such as a phase plate suitably used in a broadband range and a polarizing diffraction element excellent in diffraction efficiency, a polymerizable liquid crystal composition to be used for them, and an optical head device using them.

Abstract: A strap for diving face mask includes an upper branched sub-section and a lower branched sub-section forming together a loop section in a middle zone of the strap as viewed lengthwise. The upper branched sub-section has a circumferential length larger than a circumferential length of the lower branched sub-section and preferably right and left halves of the strap are sloped toward the side of the lower branched sub-section.

Abstract: A liquid crystal lens element is provided, which can realize a small sized element having no moving part, and which has a lens function of switching the focal length among multiple focal lengths of at least 3 types according to an applied voltage.

Abstract: A layered polarized diffractive filter capable of changing the wavelength of light to be transmitted or diffraction-shielded is provided. A polarized diffractive filter is capable of receiving light having at least two different peak wavelengths so as to shield light having at least one of the peak wavelengths by diffraction and to transmit light having the other peak wavelengths. The polarized diffractive filter comprises transparent substrates 11, 13 on which cyclic concave/convex portions 12 are formed as a diffractive grating and the concave/convex portions 12 are filled with a liquid crystal material as an optical member, thereby constituting a diffractive filter. The layered polarized diffractive filter comprises two polarized diffractive filters layered so that longitudinal directions of the diffractive grating of the polarized diffractive filters intersect orthogonally each other.