Abstract: In a laser processing method for accurately forming a convexo-concave structure on the surface of a glass substrate, a periodic optical intensity distribution of a laser beam is obtained by an interference between diffracted light beams of +1 degree and ?1 degree emitted from a phase mask, onto which the laser beam is irradiated, in the vicinity of the emission side of the phase mask, and a glass substrate, on which a thin film is formed, is set in the area where the periodic optical intensity distribution is provided. As a result, the thin film is evaporated or ablated depending on the periodic optical intensity, thereby a diffraction grating, which has the same period as that of the varying optical intensity, is formed on the glass substrate.

Abstract: An object sensor is provided, which has a high object detection rate with respect to an object such as a raindrop adhering to a detection surface, and which is capable of detecting the presence/absence of an object with a high sensitivity. A light source 10, a detection surface 110, a focusing lens 40, and a plurality of photodetecting elements of a photodetecting unit 50 form a focusing system of equal magnification that is capable of catching an image in a size smaller than an object to be detected. Light emitted from the light source 10 is incident on the detection surface 110 via a prism 20 at a predetermined incident angle. Without a raindrop 120, the total internal reflection condition is satisfied as shown by a path 140 of a beam, so that the beam is subjected to the total internal reflection. Then, the beam passes through a prism 30, and is focused on a photodetecting surface of the photodetecting unit 50 by the focusing lens 40.

Abstract: An optical element according to the invention uses a thin film-like two-dimensional photonic crystal having a structure of periodic repetition in two directions perpendicular to each other. When the two periodic directions are Y-axis and Z-axis directions, opposite surfaces of the photonic crystal structure perpendicular to the Z-axis direction and parallel to the Y-axis direction are used as a light input surface and a light output surface respectively. The direction of movement of light rays incident onto the light input surface is decided so that it is parallel to the YZ plane and inclined at a predetermined inclination angle to the Z-axis direction.

Abstract: An optical element of the present invention includes a structure having at least one convex portion and at least one concave portion formed so as to be adjacent to either one of the convex portions. At least one surface of the structure is covered, and the optical element has a hollow portion. At least one surface of the structure is covered with a covering layer formed by a deposition process.

Abstract: A processing method for glass substrate of the present invention includes: applying heat and external force to a glass substrate and then cooling it down to thereby form a compression stressed part having a different etching rate from that of other parts with respect to an etching reagent to be used, on the surface of the glass substrate and in the vicinity thereof, and performing chemical etching using the etching reagent on the glass substrate having the compression stressed part formed thereon, so as to form a relief on the surface of the glass substrate.

Abstract: A micro prismatic structure is formed inside the light transmission face of a gradient-index lens, in which the projections have a height of at least 0.25 ? and the distance between the neighboring projections is at most ?, based on the applied wavelength ?. Preferably, the micro prismatic structure has conical projection units that are aligned in the light transmission face of the lens in a mode of hexagonal, tetragonal or orthorhombic arrangement. The conical projections may be in any form of circular cones, polygonal cones, flat-headed circular cones (circular cones of which the apex has been cut horizontally) or flat-headed polygonal cones .

Abstract: The present invention improves a method of forming a surface unevenness using a difference in etching rates, and relaxes limitations on substrates in this method. In a method of the present invention, an uneven surface is formed by a method including applying pressure to a predetermined region in a surface of a thin film formed on a substrate, and etching a region including at least a portion of the predetermined region and at least a portion of the reminder of the surface that excludes the predetermined region. An etching rate difference within the thin film increases freedom in selecting a substrate material.

Abstract: A diffraction device using a photonic crystal includes a diffraction grating, which has a period and periodically divides electromagnetic waves, and an input medium and an output medium, which contact the diffraction grating. The input medium is air, and the output medium is a one-dimensional layer having a periodic characteristic in a single direction (Z axis direction). The photonic crystal is formed by a periodic multilayer film having a period corresponding to the sum of the thickness of a first substance and the thickness of a second substance, which are superimposed. The diffraction device drastically decreases the resolution corresponding to the difference of the separated frequencies.

Abstract: A deposit detector in which deposit on a detection surface has a surface shape effect, and generation of a flashing phenomenon caused by irregular reflection of the light incident on the deposit from the outside is estimated. In a deposit detection mode, light emitted from a light source (10) for total reflection and total-reflected from the detection surface is received by a light-receiving element unit (50). Each element is disposed at such an angle that the light undergoes total reflection when no deposit is present or the condition of total reflection is not satisfied when deposit is present. Further, in a light-scattering deposit detection mode, light emitted from a scattering light source (20) and scattered by the detection surface is received by the light-receiving element unit (50). In an extraneous light quantity increase detection mode, extraneous light is received by the light-receiving element unit (50).

Abstract: In a laser processing method for accurately forming a convexo-concave structure on the surface of a glass substrate, a periodic optical intensity distribution of a laser beam is obtained by an interference between diffracted light beams of +1 degree and −1 degree emitted from a phase mask, onto which the laser beam is irradiated, in the vicinity of the emission side of the phase mask, and a glass substrate, on which a thin film is formed, is set in the area where the periodic optical intensity distribution is provided. As a result, the thin film is evaporated or ablated depending on the periodic optical intensity, thereby a diffraction grating, which has the same period as that of the varying optical intensity, is formed on the glass substrate.

Abstract: A micro prismatic structure is formed inside the light transmission face of a gradient-index lens, in which the projections have a height of at least 0.25 &lgr; and the distance between the neighboring projections is at most &lgr;, based on the applied wavelength &lgr;. Preferably, the micro prismatic structure has conical projection units that are aligned in the light transmission face of the lens in a mode of hexagonal, tetragonal or orthorhombic arrangement. The conical projections may be in any form of circular cones, polygonal cones, flat-headed circular cones (circular cones of which the apex has been cut horizontally) or flat-headed polygonal cones .

Abstract: An optical element using one-dimensional photonic crystal according to the invention includes a multilayer film, which is achieved by an element processed into a triangular prism shape. A phase modulation unit is provided so as to be adjacent or abutting to a light input end surface of the optical element. Input light is phase-modulated by the phase modulation unit in the same period and direction as those of photonic crystal so that only specific high-order band light can be propagated through the optical element. When this optical element is formed in an optical waveguide, a small-size spectroscopic device having high resolving power can be provided.

Abstract: An optical element according to the invention uses a thin film-like two-dimensional photonic crystal having a structure of periodic repetition in two directions perpendicular to each other. When the two periodic directions are Y-axis and Z-axis directions, opposite surfaces of the photonic crystal structure perpendicular to the Z-axis direction and parallel to the Y-axis direction are used as a light input surface and a light output surface respectively. The direction of movement of light rays incident onto the light input surface is decided so that it is parallel to the YZ plane and inclined at a predetermined inclination angle to the Z-axis direction.

Abstract: A limited portion of a surface of a glass substrate is removed by application of a laser beam on the limited portion of the glass substrate to thereby produce a glass structure according to the invention. The glass substrate contains at least one element such as titanium, iron, vanadium, bismuth, lead, thallium, tin, cerium, rhodium or cobalt capable of absorbing energy of the laser beam and has a threshold of not larger than 1.0 J/cm2 per laser beam pulse in terms of machining energy of the laser beam. When such a glass substrate 21 is used, a glass structure having a through-hole 61 or cavity optional in sectional shape can be formed by irradiation with the laser beam 10.

Abstract: A method of forming a micro groove structure according to the invention has the steps of: (a) forming a mask pattern on a substrate capable of being subjected to dry etching; (b) dry etching the substrate having the mask pattern formed thereon; (c) vapor-phase forming a thin film of a masking material for the dry etching, on a non-etched surface portion of the substrate after the dry etching; and (d) dry etching the substrate having the thin film formed thereon. The steps (a) to (d) are carried out successively.

Abstract: In a laser processing method for accurately forming a convexo-concave structure on the surface of a glass substrate, a periodic optical intensity distribution of a laser beam is obtained by an interference between diffracted light beams of +1 degree and −1 degree emitted from a phase mask, onto which the laser beam is irradiated, in the vicinity of the emission side of the phase mask, and a glass substrate, on which a thin film is formed, is set in the area where the periodic optical intensity distribution is provided. As a result, the thin film is evaporated or ablated depending on the periodic optical intensity, thereby a diffraction grating, which has the same period as that of the varying optical intensity, is formed on the glass substrate.

Abstract: The present invention provides an object-sensing device capable of estimating the presence of an object attached on a sensing surface, the kind of the object and the state of the object. An image is formed by a lens with light via the sensing surface, and the light is received by a light-receiving element portion in which a plurality of micro-light-receiving elements are arranged. In the object detection mode, totally reflected light from the sensing surface is received by the light-receiving element portion. The components are arranged at an angle that allows total reflection when there is no object, and does not allow the total reflection condition to be satisfied when there is an object. In the light scattering object detection mode, scattered light from the sensing surface is received by the light-receiving element portion. A signal pattern is obtained by joining detection signal levels of the micro-light-receiving elements in accordance with the arrangement of the micro-light-receiving elements.

Abstract: An optical element according to the invention constituted by a multilayer structure having a periodic structural portion as at least one region constituted by repetition of a predetermined period, wherein an end surface of the multilayer structure not parallel to layer surfaces of the multilayer structure is used as a light input surface whereas one or each of opposite surfaces of the multilayer structure parallel to the layer surfaces is used as a light output surface. The periodic structural portion of the multilayer structure can be regarded as a one-dimensional photonic crystal. Refracted light from the one-dimensional photonic crystal has good directivity and the direction of the refracted light has strong dependence on wavelength. When this wavelength dependence property is used, a spectroscopic device or a polarized light separating device of high resolution can be achieved without increase in device size.

Abstract: An object sensor is provided, which has a high object detection rate with respect to an object such as a raindrop adhering to a detection surface, and which is capable of detecting the presence/absence of an object with a high sensitivity. A light source 10, a detection surface 110, a focusing lens 40, and a plurality of photodetecting elements of a photodetecting unit 50 form a focusing system of equal magnification that is capable of catching an image in a size smaller than an object to be detected. Light emitted from the light source 10 is incident on the detection surface 110 via a prism 20 at a predetermined incident angle. Without a raindrop 120, the total internal reflection condition is satisfied as shown by a path 140 of a beam, so that the beam is subjected to the total internal reflection. Then, the beam passes through a prism 30, and is focused on a photodetecting surface of the photodetecting unit 50 by the focusing lens 40.

Abstract: A method for producing an aspherical structure according to the invention includes the steps of: forming a layer on a surface of a substrate so that the layer exhibits an etching rate distribution in a direction perpendicular to the surface of the substrate; forming a mask having a predetermined opening shape on the surface of the layer; and etching the layer to thereby form at least one aspherical concave portion. When each concave portion is used as a molding tool so that a resin with which the concave portion is filled is solidified and removed from the concave portions an aspherical lens array can be formed accurately.