Abstract: By hiding at least blackened portions from outside to make visual confirmation thereof impossible, a fluorescent lamp keeps its clean outward appearance until its service life expires and insufficiency of luminance on ends of the fluorescent lamp is dissolved. The fluorescent lamp comprising a plurality of discharging electrodes in a glass tube, and wherein the glass tube comprises an illuminating glass tube portion coated at inner wall surfaces thereof with a fluorescent substance and functioning as an illuminating body, and auxiliary glass tube portions provided contiguous to the illuminating glass tube portion and hidden from outside by shielding members, and wherein the discharging electrodes are not provided in the illuminating glass tube portion but mounted in the auxiliary glass tube portions.

Abstract: An optical multi-demultiplexer of the present invention comprises an input waveguide to which wavelength division multiple signals are applied, a plurality of output waveguides for demultiplexing and outputting the wavelength division multiple signals, an arrayed waveguide including a plurality of channel waveguides having different waveguide lengths, an input slab waveguide, and an output slab waveguide. The input slab waveguide is provided between the input waveguide and the arrayed waveguide. The output slab waveguide is provided between the arrayed waveguide and the output waveguides. The input slab waveguide is formed with tapered island regions having a refractive index lower than that of the core layer of the slab waveguide. The island regions are situated in positions opposite the channel waveguides of the arrayed waveguide.

Abstract: By hiding at least blackened portions from outside to make visual confirmation thereof impossible, a fluorescent lamp keeps its clean outward appearance until its service life expires and insufficiency of luminance on ends of the fluorescent lamp is dissolved. The fluorescent lamp comprising a plurality of discharging electrodes in a glass tube, and wherein the glass tube comprises an illuminating glass tube portion coated at inner wall surfaces thereof with a fluorescent substance and functioning as an illuminating body, and auxiliary glass tube portions provided contiguous to the illuminating glass tube portion and hidden from outside by shielding members, and wherein the discharging electrodes are not provided in the illuminating glass tube portion but mounted in the auxiliary glass tube portions.

Abstract: Proposed is a method for fabricating a planar optical waveguide device having a plurality of core segments formed between a lower clad layer and an upper clad layer, in which a hot isostatic pressing process (HIP) is carried out during the fabrication process. The lower clad layer may consist of a substrate or a buffer layer formed on a substrate. Each layer may be formed either by a low-temperature film-forming process such as CVD or by the flame hydrolysis pressing process. The HIP process is also effective in eliminating voids when the core is formed in a recess of the lower clad layer. According to the tests conducted by the inventors, it was found that the HIP process can be conducted without requiring any protective layer or a gas barrier through proper selection of the condition for the HIP process, as opposed to the common belief that a protective layer or a gas barrier is essential for the HIP process.

Abstract: An optical multi-demultiplexer of the present invention comprises an input waveguide to which wavelength division multiple signals are applied, a plurality of output waveguides for demultiplexing and outputting the wavelength division multiple signals, an arrayed waveguide including a plurality of channel waveguides having different waveguide lengths, an input slab waveguide, and an output slab waveguide. The input slab waveguide is provided between the input waveguide and the arrayed waveguide. The output slab waveguide is provided between the arrayed waveguide and the output waveguides. The input slab waveguide is formed with tapered island regions having a refractive index lower than that of the core layer of the slab waveguide. The island regions are situated in positions opposite the channel waveguides of the arrayed waveguide.

Abstract: An optical device comprises a substrate, an optical waveguide, a laser diode, photodiodes, and a filter. The substrate is provided with a flat reference surface and a V-groove recessed from the reference surface. A pin is fitted in the V-groove of the device and a V-groove of a connector. The optical waveguide is formed on the reference surface. The optical waveguide is provided with a core and a cladding. The core extends along the reference surface. The laser diode emits a signal light beam with a first wavelength toward the core and the photodiode, individually. The filter transmits the signal light beam with the first wavelength and reflects a signal light beam with a second wavelength. The signal light beam reflected by the filter is received by a photodiode.

Abstract: A pair of electrodes (1a, 1b) are formed on one surface of a dielectric substrate (2). A dielectric layer (18) is formed on the surface of the dielectric substrate (2) so as to cover the pair of electrodes (1a, 1b). The pair of electrodes (1a, 1b) have linear electrode elements, respectively. The respective linear electrode elements are arrange at equal intervals.

Abstract: A pair of electrodes (1a, 1b) are formed on one surface of a dielectric substrate (2). A dielectric layer (18) is formed on the surface of the dielectric substrate (2) so as to cover the pair of electrodes (1a, 1b). The pair of electrodes (1a, 1b) have linear electrode elements, respectively. The respective linear electrode elements are arrange at equal intervals.

Abstract: A laminate-type metallic gasket comprising adjacent combustion chamber holes (A, A), a pair of bead substrates (3, 4) made of an elastic metallic plate with a bead (1) formed along each of the combustion chamber holes (A, A) and first and second intermediate plates (6, 8), in which peak portions of beads (1) are symmetrically opposite to each other, disposed between the two bead substrates (3, 4) according to the present invention wherein a first intermediate plate (6) is provided with a step (9) having a thickness less than that of a second intermediate (8) formed along an edge portion (7) of the combustion chamber holes (A, A).

Abstract: An optical waveguide device is provided with a core formed on a substrate and a clad layer. A low-temperature film-forming method, such as the CVD or PVD method, is used in a core forming process for forming the core and a clad forming process for forming the clad layer. The surface of the clad layer is coated with a protective film of chrome or the like in a protective film forming process that is carried out after the clad forming process. In a heating/pressurizing process that is carried out after the protective film forming process, the clad layer is heated and pressurized from its outside by the HIP (hot isostatic pressing) method. This heating/pressurizing process substantially eliminates voids in the clad layer and the like, and enhances or improves the density of a buffer layer, core, and upper clad layer and the transparency of the core layer. The protective film is removed by etching or the like in a removing process.

Abstract: The metallic gasket consists of a first elastic metallic plate having beads and folded portions and a second elastic metallic plate having beads, laminated on each other. The folded portions are formed by bending the plate alone the circumferences of cylinder bore holes, and the beads are formed on the portions of the plate spaced from the circumferences of the cylinder bore holes at a predetermined distance in the radially outward direction thereof, whereby double annular seal portions are formed. The projecting portions of the beads on the second elastic metallic plate are fitted in or brought into contact with the recessed portions or projecting portions of the beads on the first elastic metallic plate. The spring constant of the gasket becomes equal to the sum of those of the two plates, and this enables the stress carried by the plates to be lessened, and the durability of the gasket to be improved.

Abstract: At the portions of the metallic gasket according to the present invention which are around perforations the inner diameter of which is smaller than that of holes for combustion chamber, the thickness of at least the folded portions and the portions of an elastic metallic plate on which these folded portions are laminated are reduced to a level in the range from a level not higher than that of the thickness of said metallic plate to a level not lower than that of a half of the thickness of said metallic plate. These thickness-reduced portions of the metallic plate are bent onto the bead-ridge-carrying side thereof to form folded portions, whereby the thickness of the folded portions is reduced to provide a difference in height between the folded portions and the bead-surrounding portions of the metallic plate. The metallic plate is heat treated after the folding step has been completed, to regulate the hardness of the metallic plate.

Abstract: This invention provides a metal gasket and its production method which prevents damage to folded portions by fold-machining and damage to metal materials after fastening, and expands the range of selection of materials for elastic metal plates, by reducing the thickness of a predetermined region of a elastic metal plate at which folded portions are to be formed. The thickness of the folded portion of the elastic metal plate is reduced from the folding side in an inner region of folded base portions and in regions in which folded free ends are positioned. Bend-machining is made gently at the folded base portions subjected to fold-bend machining, and the folded base portions each have a gap there-inside. The folded free ends do not come into contact with the elastic metal plate due to recessed surfaces. Accordingly, cracks and wrinkles do not occur at the folded base portions, and the folded free ends do not leave friction traces on the elastic metal plate.

Abstract: In the metallic gasket according to the present invention, beads are formed on the circumferential portions of the first cylinder bore-aligned holes in the base member, and folded portions are formed on the auxiliary member by merely folding back the inner edge sections of the second cylinder bore-aligned holes therein so as not to embrace the bead-carrying base member, the auxiliary member being laminated on the side of the base member from which the beads project. In this metallic gasket, the folded portions of the auxiliary member restrict the deformation of the beads to minimize the occurrence of fatigue and cracks in the beads, whereby the sealing function of the gasket is improved with uniform and proper surface pressure distribution maintained. Soft members are provided between the main portion of the auxiliary member and the folded portions thereof so as to secure proper surface pressure distribution in the metallic gasket in accordance with the rigidity of the cylinder head.

Abstract: This metal gasket interposes a regulation plate having compression stop portions and beads between first and second elastic metal plates the convexities of beads of which face one another. The compression stop portions prevent complete compression of each bead and absorbs any irregularity between opposed fitting surfaces around holes for a combustion chamber. An intermediate plate having an offset portion is sandwiched between the regulation plate and the second elastic metal plate. The offset portion is shaped to a height smaller than the thickness of the compression stop portions and regulates the degree of compression of each bead.

Abstract: Disclosed is a metal gasket for a manifold produced by laminating a plurality of bead plates having bead portions which are bent at a predetermined radius of curvature R and by setting the ratio R/t of the radius of curvature R to the thickness t of the bead plates to the range of 7 to 15. Therefore, the radius of curvature of the bent portions of the bead plates to the thickness can be made relatively great and the bent portions of the bead plates become smooth. As a result, when the metal gasket is tightened between a cylinder head and an exhaust manifold, the contact portions of the bead plates are expanded and the stress and face-to-face pressure occurring at the contact portions can be reduced. Accordingly, the stress acting on the bead plates can be made lower than a reference value, the increase of the facet-face pressure can be restricted to within a predetermined range and the stress and face-to-face pressure of the bead portions forming a seal surface can be kept within suitable ranges.

Abstract: This invention discloses the method of manufacturing metallic gaskets which are properly prestressed by a load which is determined according to a stress calculation. In the process of applying prestresses to the gaskets, a die formed to a thickness smaller than the thickness of the metallic gasket material--which has a bead portion and is coated with resin such as a fluoroelastomer--is placed close to and surrounding the outer circumference of the metallic gasket material or inside the holes formed in the metallic gasket material. Then, the tension side of the bead portion of the metallic gasket material is prestressed by a stress greater than a specified stress that will occur when the metallic gasket is used.