Abstract: A lighting unit is disclosed having an electrodeless low pressure discharge lamp which is provided with a discharge vessel closed in a gastight manner and comprising an ionizable filling. The discharge vessel has a recessed portion and an enveloping portion. The recessed portion and the enveloping portion each have a fastening to a metal collar, a coil being arranged in the recessed portion for generating a high-frequency magnetic field for maintaining an electric discharge in the discharge vessel. The enveloping portion is provided at an inner surface with a light-transmitting, electrically conductive layer. The conductive layer is electrically connected to a lead-through member of which the metal collar forms part in that the conductive layer covers a region of the lead-through member which adjoins the inner surface of the enveloping portion and which is at a distance from at least one of the fastenings between the discharge vessel and the collar.

Abstract: A low pressure discharge lamp having a tubular discharge vessel (1). At each of its end portions (2, 3) the vessel (1) is fused to a respective metal tube (5) having an uncovered outer surface outside the vessel. A sealed glass tube (6) is fused to the metal tubes (5). Ignition aids (18, 28, 40) may also be present. The simple construction of the lamp permits manufacture and high lamp quality, even at long lengths and/or small diameters of the discharge vessel. The lamp may have an ionizable filling of rare gas or may also contain mercury. A fluorescent powder may also be present in the discharge vessel. The lamp (72) and a luminaire (70, 71) mounting the lamp may be used for display or signalling purposes.

Abstract: Low-pressure mercury vapor discharge lamp with an emission spectrum according to a spectral energy distribution comprising the wavelength ranges 380-490 nm, 490-590 nm, and 590-700 nm, within which wavelength ranges mutually equal or substantially equal quantities of energy are emitted with a tolerance of 25% for the mutual ratios of equal energy of 1:1:1.

Abstract: The low-pressure discharge lamp has a tubular lamp vessel provided at its both ends with a lamp cap having a pair of contact pins. Each lamp cap is fixed in an adapter having one central contact pin electrically connected to at least one of the pair of contact pins of the lamp cap. A lamp of ordinary construction when provided with the adaptor is thus suitable for use in a space containing explosive gas.

Abstract: The invention relates to a blown lamp bulb having a parabolically curved wall portion, a neck-shaped wall portion near the apex of the parabolically curved wall portion. The bulb has a an axis of symmetry and a largest diameter. A curved wall portion is opposite the parabolic wall portion and has a focus which is located near the neck-shaped wall portion. The curved wall portion has a spherically curved portion having a center of curvature on the largest diameter or above it and a flattened portion proximate the axis of symmetry. The lamp bulb renders it possible to manufacture, by the choice of the finish of the lamp bulb, a large number of lamp types.

Abstract: A lamp includes a tube which forms part of a sealed vessel, extending between a lamp cap and a pinch at an end of the tube inside the vessel. A current supply conductor extending between a cap contact and a light source inside the vessel includes a fuse wire portion which is embedded in an electrically insulated mass within the tube, part of the fuse wire portion being free of the insulating mass, between the mass and the lamp cap.

Abstract: An electric reflector lamp according to the invention has a blown lamp envelope comprising a concave internally mirror-coated wall portion, a spherical internally mirror-coated wall portion opposite thereto, an annular translucent wall portion between the first two portions and a tubular wall portion at the apex of the concave wall portion. These wall portions constitute a single blow moulding. The axes of the mirror-coated wall portions coincide, just like their focus and center of curvature, around which a light source is arranged. The concave wall portion is parabolic or elliptic, the second focus lying outside the lamp envelope. The parts of the mirror-coated wall portions, which throw light rays after at most two reflections through the translucent wall portion to the exterior, surround the focus through a solid angle of more than 1.5 .pi.sr.

Abstract: A flashbulb unit comprising a housing, a plate-shaped support in the housing and an electrical circuit which is provided on the support and in which flashbulbs and break switches are incorporated. The unit comprises pushbuttons which are incorporated in a wall of the housing and which are arranged each opposite to a break switch and operate the break switch when being depressed.

Abstract: A flash bulb unit comprising a plate-shaped support on which an electric circuit is provided. The circuit includes a plurality of combustion flash bulbs. On the side of the support remote from the bulbs the unit has an opaque plate. The plate and the support are each provided with holes aligned with at least one flash bulb. A foil is disposed intermediate the plate and support which substantially blocks light rays until the bulb is flashed whereupon the heat melts the foil. The hole in the support increases in diameter from the side on which the bulb is disposed to the opposite side and is narrower on the side of the bulb than the hole in the plate. The part of the support situated adjacent to the hole in the plate has a color contrasting with that of the foil.

Abstract: The invention relates to a flash array provided with a number of high voltage combustion flash lamps which each cooperate with a single reflector sheet of an electrically conducting material. This reflector sheet is provided with holes; when a lamp is flashed a radiation-sensitive switching contact is affected via one of the holes.According to the invention the radiation-sensitive contacts open responsive to radiation. These contacts and the reflectors are connected to one another via a low-ohmic connection and whereby further a lamp, whose turn has not yet come, is short circuited. These measures result in the fact that the chance for premature ignition of a lamp is extremely small.