摘要:
An optical device having a sub-wavelength grating formed in a specified region is disclosed that is able to prevent wave front degradation accompanying a phase difference of a polarized light beam passing through the optical device. The optical device includes a circular-belt-like region where the sub-wavelength diffraction grating is formed, and a center portion where the sub-wavelength diffraction grating is not formed. A vertically polarized light beam used for operations on a blue-light optical recording medium A has a phase difference in the sub-wavelength diffraction grating to be an integral multiple of 2π and hence is transmitted through the sub-wavelength diffraction grating. A horizontally polarized light beam used for operations on a blue-light optical recording medium is diffracted by the sub-wavelength diffraction grating. The light path length L1 of the light beam passing through the circular-belt-like region is the same as that of the light beam passing through the center portion without the sub-wavelength grating.
摘要:
To provide a gradation mask which can easily assure distribution of desired exposure intensity. �Means to accomplish the object!A metal and/or metallic compound film 2 (FIG. 1) is uniformly formed on a transparent substrate 1 such that they have a transmittance of 10% or less. An etching mask having a desired pattern is formed on the metal and/or metallic compound film 2. The metal and/or metallic compound film 2 is dry- or wet-etched. The metal and/or metallic compound film 2 is repeatedly subject to patterning and etching steps by using etching masks with different patterns, so that the obtained layers have a thickness Z(X, Y) varying in three or more steps in accordance with desired transmittance.
摘要:
An optical information recording medium, for writing in and reading out information by a laser beam, is composed of a recording layer, an anti-reflection layer structure formed on an outer surface section on which the laser beam is directed to be focused, on the recording layer, and the anti-reflection layer structure includes one or more transparent electroconductive film layers.
摘要:
Disclosed is a reflecting wavelength plate that deflects and reflects a light path and adds a phase difference with respect to plural incident light having different wavelengths. The reflecting wavelength plate includes a substrate; a reflecting film laminated on the substrate; and a sub-wavelength concavo-convex structure that is laminated on the reflecting film and has a pitch less than or equal to the shortest wavelength of the plural incident light. The filling factor and the groove depth of the sub-wavelength concavo-convex structure are determined so as to add the phase difference obtained by (kπ)/8, where k is an integer, to the plural incident light having the different wavelengths.
摘要:
A two-dimensional shape of a dotted pattern and optical densities of dots or sizes of dots having the same optical density are calculated as write data on the basis of a target distribution of transmittance. The dotted pattern is optically written on a photosensitive medium in accordance with the calculated write data, using a beam from a light source whose output is stepwise or sequentially variable. A latent dotted pattern on the photosensitive medium is developed, thereby obtaining an exposure mask having a desired two-dimensional distribution of transmittance expressed by the dotted pattern and the optical densities of dots or the sizes of dots having the same optical density.
摘要:
Disclosed is a reflecting wavelength plate that deflects and reflects a light path and adds a phase difference with respect to plural incident light having different wavelengths. The reflecting wavelength plate includes a substrate; a reflecting film laminated on the substrate; and a sub-wavelength concavo-convex structure that is laminated on the reflecting film and has a pitch less than or equal to the shortest wavelength of the plural incident light. The filling factor and the groove depth of the sub-wavelength concavo-convex structure are determined so as to add the phase difference obtained by (kπ)/8, where k is an integer, to the plural incident light having the different wavelengths.
摘要:
A disclosed optical pickup includes an aberration correction unit with a phase shifter surface. On the phase shifter surface, rectangular or staircase-like steps are formed in a concentric manner around an optical axial center, in certain regions where a light beam passes through. The steps have different heights in the optical axial direction. A light beam having a wavelength of 405 nm is directly transmitted through the steps so that a phase difference is applied for correcting spherical aberration that occurs on a first optical recording medium. A light beam that passes through an annular region without any steps is focused on a second optical recording medium. A light beam that passes through an outside region is focused by an object lens on the second optical recording medium, and is not focused on the first optical recording medium.
摘要:
An optical device having a sub-wavelength grating formed in a specified region is disclosed that is able to prevent wave front degradation accompanying a phase difference of a polarized light beam passing through the optical device. The optical device includes a circular-belt-like region where the sub-wavelength diffraction grating is formed, and a center portion where the sub-wavelength diffraction grating is not formed. A vertically polarized light beam used for operations on a blue-light optical recording medium A has a phase difference in the sub-wavelength diffraction grating to be an integral multiple of 2π and hence is transmitted through the sub-wavelength diffraction grating. A horizontally polarized light beam used for operations on a blue-light optical recording medium is diffracted by the sub-wavelength diffraction grating. The light path length L1 of the light beam passing through the circular-belt-like region is the same as that of the light beam passing through the center portion without the sub-wavelength grating.
摘要:
An optical pickup is disclosed that includes a simplified phase correction element enabling sufficient correction of spherical aberration and realization of compatibility with blue-light, DVD-type and CD-type optical recording media with a two-stage numerical aperture switching operation. The phase correction element includes a phase shifting part and a diffraction part superposed on the phase shifting part. The phase shifting part has stepwise concentric circular regions including more than two stages. The diffraction part includes periodically arranged projecting and depressed portions formed on the phase shifting part. The phase shifting part suppresses spherical aberration related to red light used for a DVD-type optical recording medium when the object lens is optimized relative to blue light used for a blue-light optical recording medium. The diffraction part sets a most appropriate NA to each of the blue-light, DVD-type and the CD-type optical recording media by switching the numerical aperture.
摘要:
A method of fabricating a mold and a method of fabricating an article with the mold is disclosed that is capable of fabricating a high three-dimensional surface structure and extending the service life of the mold. A mold having a fine surface shape of a height less than an object height is fabricated, then the fine surface shape of the mold is transferred to an intermediate mold by dry-etching, and then the fine surface shape of the intermediate mold is further transferred to a final article material by dry-etching. In each transfer step by dry-etching, the etching selection ratio is appropriately adjusted to increase the height of the fine surface structure step by step, so that the fine surface shape of the final article material has the object height. On the surface of the final article material, a preliminary pattern of the object surface shape may be formed beforehand to reduce the required thickness of the curable resin.