Abstract: The electric discharge lamp has a discharge vessel (2), which is mounted in an outer bulb (1). A glass sleeve (10) is surrounding the discharge vessel. A coiled wire (11) is used as an envelope (11) to a glass sleeve. The wire is in an electrically floating manner fixed around the sleeve (10), e.g. by clamping fit. The construction of the lamp is simple an effective to protect the outer bulb (1) from being damaged by an explosion of the lamp vessel (2) and to prevent sodium, if present, to disappear from the discharge vessel as a result of photoemission.

Abstract: An electric reflector lamp is disclosed having a reflecting surface and a neck. A light source having a glass lamp vessel with a pinch seal is accommodated in the reflector body, the pinch seal being located in the neck. A mounting plate is present on the pinch seal. The plate is the bottom of a bush which extends axially along the lamp vessel towards the reflecting surface and which has a transversely extending rim which closes the neck.

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 mercury vapor discharge lamp according to the invention is provided with a discharge vessel (10) which encloses a discharge space (11) containing mercury and a rare gas in a gaslight manner. The discharge vessel (10) has a light-transmitting tubular portion (12) and a first and a second end portion (13A, 13B). Current supply conductors (20A, 20A'; 20B, 20B') issue through each end portion (13A, 13B) to respective electrodes (21A, 21B) arranged in the discharge space (11). The lamp is further provided with a main amalgam (30) for stabilizing the mercury vapour pressure in the discharge space (11) during normal operation, and with an auxiliary amalgam (31A, 31B) for quickly releasing mercury into the discharge space (11) after switching-on of the lamp. In an equilibrium state at room temperature (25.degree. C.), the mass (m.sub.Hg in mg) of the quantity of mercury absorbed in auxiliary amalgam (31A, 31B) is at most 20 times the mercury vapour pressure (P.sub.

Abstract: The packaging carton of the packed electric lamp has an incision line through diagonally opposed edges in respective side walls adjoining these edges. Boundary lines extend in each of the two side walls from said incision line to a point P of the edge, which point lies closer to the first end, so as to define together with the incision line a region of said walls which is flipped over as a folded portion into the carton, thus narrowing the carton. The lamp may be readily machine packed into the carton, starting from the back of the carton, and displays essential distinguishing marks of its bulb while the packaging remains closed.

Abstract: The electric lamp (1) has a lamp vessel (2), wherein an electric element (3) is accommodated. This element is connected to current conductors (4). Molybdenum end portions (5) of the current conductors extend outside the lamp vessel and have a skin of molybdenum nitride as a protection against oxidation.

Abstract: The packed electric lamp has a back wall with a first sleeve comprising a base and a first fixation wall with an opening, and a second sleeve comprising a top and a second fixation wall with an opening. Side walls are connected to the back wall and fastened to the first and second sleeves by means of folded tongues. The lamp is held fixed in the with respective end portions. The packing keeps the lamp securely fixed in place, while nevertheless a substantial portion of the lamp is visible. The packing may be readily shaped from its blank and simultaneously made to hold the lamp.

Abstract: A method of selecting low-pressure mercury discharge lamps comprising a luminescent layer, the luminescent layer being excited and the low-pressure mercury discharge lamps being selected in dependence on the emission spectrum of the visible light emitted by the luminescent layer. The luminescent layer is excited by a light source arranged outside the low-pressure mercury discharge lamp and which generates ultraviolet radiation having a wavelength above 300 nm. This makes it possible to use the presence of a blue-luminescent substance in the luminescent layer as a selection criterion for both leaky and intact low-pressure mercury discharge lamps.

Abstract: The electric reflector lamp has a reflector body with a light-beam shaping surface which comprises a body of revolution of a branch of a parabola which has been tilted towards the optical axis of the light-beam shaping surface. The light-beam shaping surface has superimposed plane axial lanes of which the number in a first zone remote from the light emission window is half that in a second zone adjacent said window. The axial lanes give the light-beam shaping surface cross-sections which are regular polygons. A light source is positioned on the optical axis, while the focus is inside this light source. The lamp has a universal burning position, a good mixing of the generated light, and a comparatively high luminous flux in the beam.

Abstract: A low-pressure mercury vapor discharge lamp with a tubular discharge vessel (1) with an internal diameter D. The discharge vessel (1) encloses a discharge space (3), which comprises mercury and a rare gas, in a gastight manner. Electrodes (5A, 5B) are arranged in end portions (4A, 4B) of this discharge space. The discharge vessel (1) has a luminescent layer (10) which supports a protective layer (11) comprising a metal oxide at an inner surface (9). In the lamp according to the invention, at least 75% by weight of the metal oxide is present in total in the end portions (4A, 4B), said end portions (4A, 4B) each extending up to a distance beyond the electrodes (5A, 5B) which is three times the internal diameter of the discharge vessel (1). The lamp has a comparatively low luminous decrement and can be manufactured comparatively efficiently.

Abstract: A high pressure gas discharge lamp includes first and second discharge devices electrically connected in series within an outer envelope. The discharge devices each include a discharge vessel enclosing a discharge space with an ionizable fill and first and second discharge electrode assemblies. The first discharge electrode assemblies of the discharge devices are connected so as to receive a starting pulse and lamp operating voltage. Each discharge vessel includes a first wall portion spaced from the first discharge electrode assembly and defining an ionizable gap therebetween. A conductive element bridges the discharge devices at the first wall portions and capacitively couples the first discharge electrode assemblies to induce ionization in one of the discharge devices in the ionizable gap between the first wall portion and first discharge electrode assembly.

Abstract: A low-pressure discharge lamp according to the invention is provided with a radiation-transmitting discharge vessel which encloses a discharge space containing an ionizable filling in a gastight manner, and electrodes arranged in the discharge space between which a discharge path extends. At least one of the electrodes is a sintered mixture of metal and ceramic material, the proportional quantity of metal in the mixture being small compared with the proportional quantity of ceramic material. The sintered mixture includes smaller ceramic particles with a modal diameter D1 and larger ceramic particles with a modal diameter D2, the ratio D2/D1 being at least 3, while the proportional volume of the smaller ceramic particles is small compared with that of the larger ceramic particles. In the lamp according to the invention, the electrodes have a comparatively high resistance to temperature variations in spite of the small proportional volume of metal particles.

Abstract: The capped electric lamp has a glass lamp vessel (1) having first and second neck-shaped portions (2,3). An outer glass envelope (8) has a narrowed portion (9) where it is coupled to the first neck-shaped portion (2). A metal sleeve (10) has a clamping zone (11) which clampingly holds the outer envelope (8), and a welding zone (12) to which tongues (21) of a fixation member (20) which is fixed in a lamp cap (30) are welded. The metal sleeve (10) becomes narrower from the clamping zone (11) towards the first neck-shaped portion (2) up to the welding zone (12).

Abstract: An illumination unit according to the invention comprises an electrodeless low-pressure discharge lamp 10. The illumination unit is provided with a lamp vessel 20 which encloses a discharge space 21 which contains an ionizable filling. The illumination unit is in addition provided with a holder 60 for the lamp vessel 20, with a coil 30 for generating a high-frequency magnetic field so as to maintain an electric discharge in the discharge space 21, and with a high-frequency supply 50 for the coil. The illumination unit is further provided with ignition aids 40 for promoting the initiation of the discharge.

Abstract: The luminaire has a concave reflector (1) built up from plane facets (4). The facets are arranged in rows (7) which extend between first parallel planes (8) towards the light emission window (3). The facets are also bounded by second parallel planes (9). The first and the second parallel planes extend parallel to the axis (2) of the reflector, but transversely to one another. A lamp holder (30) is present for holding an electric light source (31') in a plane transverse to the plane of symmetry (6) of the reflector. The luminaire is suitable for concentrating the light generated by the light source into a comparatively wide beam and for illuminating a field from a small distance with a high degree of homogeneity.

Abstract: An illumination unit comprises an electrodeless low-pressure discharge-lamp and a high-frequency power supply unit. The lamp has a gastight closed discharge vessel with an ionizable fill and a coil with turns of a primary and a secondary winding around a core of soft-magnetic material. The power supply unit has input terminals, a first output terminal, electrically neutral with respect to ground, that is connected to a first end of the primary winding, and a further output terminal that is connected to a second end of the primary winding. During nominal lamp operation the primary winding excites a high-frequency magnetic field that maintains an electrical discharge in the discharge vessel and that induces in the secondary winding a potential drop in the direction of a first, with respect to the electrically neutral end, to a second free end that varies in a sense opposite to the potential drop from the first to the second end in the first winding.

Abstract: The electric lamp has a quartz glass lamp vessel (10) in which an electric element (3, 4) is accommodated. The lamp vessel locally has a light-absorbing, non reflective coating (11, 12). The coating mainly consists of 2 to 10% by weight of glass which is free of lead oxide and has a softening point between 600.degree. and 700.degree. C. Iron 50 to 60% by weight, primarily in metallic form, and manganese oxide, 30 to 55% by weight, are dispersed therein.

Abstract: The low pressure sodium discharge lamp has an outer envelope (1) in which a U-shaped discharge tube (10) is accommodated. A mica disk (20) having holes (21 ) through which pinches (11) of the discharge tube extend, keeps the discharge tube centered. The mica disk (20) has teeth (22) at its periphery, which are bent towards the lamp base (5) and clampingly engage the outer envelope. The disk allows for the outer envelope to be fused to a flared tube (3) in a drop-seal process and provides several additional features.

Abstract: A novel type of leadless, black glass for use in an envelope (3) of a black light blue lamp (1) which includes CoO in an amount of 0.45 to 1.0 wt % and NiO in an amount of 2.8 to 3.4 wt %. The glass does not comprise PbO and B.sub.2 O.sub.3. The glass can be exchanged with the existing lead-containing glasses for such envelopes (3). A burning lamp (1) having such an envelope (3) emits light of the same intensity and colour as the existing lamp and emits predominantly UV-A radiation.