摘要:
An optical pickup apparatus having a light source unit including a plurality of light emitting, a beam regulating element to regulate a light flux emitted from the light source unit so that the an angle of divergence of the light flux emitted from the light source unit is changed to a first direction and/or a second direction, wherein a distance from each of the light emitting element to a surface of a protective layer that protects the recording surface is constant regardless a type of the optical information recording medium.
摘要:
An objective lens for use in an optical pickup apparatus in which first and second light sources are provided on a same flat surface, converges each of the light fluxes from the first and second light sources onto an information recording plane through each of transparent substrates of a first and second optical information recording mediums and has a coma aberration of 0.015 &lgr;1 rms or less when recording or reproducing information is conducted for the first optical information recording medium, and a coma aberration of 0.015 &lgr;2 rms or less when recording or reproducing information is conducted for the second optical information recording medium.
摘要:
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.
摘要:
An optical pickup apparatus for conducting recording and/or reproducing information for a first optical information recording medium including at least a transparent protective substrate, a first information recording surface, and a second information recording surface which are laminated in this order from a light source side along an optical axis, comprising: a first light source to emit a light flux having a wavelength of λ1 (380 nm≦λ1≦450 nm); an objective lens to converge the light flux onto the first optical information recording medium; a spherical aberration correcting structure to correct a spherical aberration caused in a converged spot on the first and second information recording surfaces due to a difference in thickness between the thickness to the first information recording surface and the thickness to the second information recording surface.
摘要:
An optical pickup apparatus for conducting recording and/or reproducing information for a first optical information recording medium including at least a transparent protective substrate, a first information recording surface, and a second information recording surface which are laminated in this order from a light source side along an optical axis, comprising: a first light source to emit a light flux having a wavelength of λ1 (380 nm≦λ1≦450 nm); an objective lens to converge the light flux onto the first optical information recording medium; a spherical aberration correcting structure to correct a spherical aberration caused in a converged spot on the first and second information recording surfaces due to a difference in thickness between the thickness to the first information recording surface and the thickness to the second information recording surface.
摘要:
An objective lens for use in an optical pickup apparatus has a diffractive optical surface. A first light flux having a first wavelength of λ1 is converged as a first number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto an information recording plane of the first optical information recording medium having a thinner protective substrate t1 by the diffractive optical surface and a second light flux having a second wavelength of λ2 (λ1
摘要:
An optical pickup apparatus conducts recording or reproducing information for an information recording plane of a first or second optical information recording medium and comprises a first light source and a second light source mounted on a same base board; a converging optical system; and a coupling lens. The converging optical system comprises an objective lens to converge a first or second light flux having passed through the coupling lens on a first or second optical information recording medium; and a diffractive structure to change a focal length in accordance with a wavelength of a light flux emitted from the first light source or the second light source.
摘要:
An optical pickup apparatus comprises a first, second and third light beam sources for emitting first light beams having wavelengths λ1, λ2 and λ3 (λ1
摘要:
A honeycomb structure includes a porous silicon carbide honeycomb fired body and a silicon-containing oxide layer. The porous silicon carbide honeycomb fired body has at least one cell wall defining a plurality of cells extending along a longitudinal direction of the silicon carbide honeycomb fired body. The plurality of cells is provided in parallel with one another. The silicon carbide honeycomb fired body contains silicon carbide particles. The silicon-containing oxide layer is provided on a surface of each of the silicon carbide particles. The silicon-containing oxide layer has a thickness of from about 5 nm to about 100 nm measured with an X-ray photoelectron spectroscopy.
摘要:
An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted ray of the second light flux, where n stands for an integer other than zero.