Electric reflector lamp

Abstract: The electric reflector lamp has a reflector body (1) of moulded glass with a neck portion (6) and a reflector portion (2). A lamp cap (25) is connected to the neck portion. An electric light source (30) is arranged with an electric element (32) inside the reflector portion (2). A mounting member (40) keeps the lamp vessel (31) fixed in the neck portion (6). A tubular body (10) is fastened with a first end portion (11) to the neck portion (6) of the reflector body (1), and supports a lamp cap at a second end portion (13). The mounting member (40) is enclosed between cooperating surfaces (7,12) of the neck portion (6) and the tubular body (10). The lamp is easy to manufacture and renders possible an increased luminous flux

Description: The invention relates to an electric reflector lamp comprising: a moulded glass reflector body with a neck portion and a reflector portion which comprises a light emission window; a lamp cap connected to the neck portion; a electric light source comprising an electric element in a gastight lamp vessel, the electric element being positioned inside the reflector portion; a mounting member which keeps the lamp vessel fixed in the neck portion; and current conductors which extend from the electric element to contacts at the lamp cap. Such a reflector lamp is known from US-A-4829210. The mounting member of this lamp is a disc which has a elastic upright rim and a central opening with tags. A seal of the lamp vessel is held in the opening by the tags. The upright rim rests with clamping fit in the neck portion of the reflector body. If the reflector body is to be moulded from molten glass, it is necessary for the neck portion to widen internally and externally towards the reflector portion at an angle of at least 3°. Otherwise the reflector body thus formed cannot be taken from the mould. A result of this is that the comparatively long neck portion is wider near the reflector portion than is necessary for accommodating the electric light source and the mounting member. This leads to a comparatively large opening in the reflector portion, with the result that the surface area of the reflector portion capable of concentrating generated light into a beam is comparatively small. The opening is also larger than is necessary for accommodating the electric light source because the mounting member has a comparatively large lateral dimension. Another disadvantage of the known lamp is that the position of the electric light source in the reflector body is uncertain. This is caused on the one hand by the fact that the electric light source may have been inserted with greater force in one lamp than in another, and on the other hand by tolerances on the dimensions of the neck portion and of the mounting member. This may lead to considerable differences between the light beams formed by the one lamp and the other lamp. The light emission window of the known lamp is closed with a cover plate after the electric light source has been provided. The cover plate is fused to the reflector body. This has the disadvantage that deformations can occur in both parts during fusion. Deformations in the cover plate are most of all disadvantageous when the cover plate also has an optical, for example beam-shaping or scattering function. US-A-4958266 discloses an electric reflector lamp in which the electric light source is secured in the lamp cap together with a mounting member. After that, the lamp cap is fastened to the reflector body. The moulded-glass reflector body has a conventional shape with a comparatively large opening in the reflector portion opposite the light emission window, and a very short neck portion. US-A-4755711 discloses a reflector lamp which has a ceramic reflector body with a comparatively long neck portion. An advantage of this is that the temperature of the lamp cap can be comparatively low during operation. The electric light source is fixed in a lump of cement in the lamp cap together with the current conductors which issue from the lamp vessel to the exterior. A disadvantage is that curing of the comparatively large quantity of cement takes much time and that many volatile ingredients may be released during this, which ingredients may become deposited in the reflector portion. Ceramic reflector bodies have the disadvantage that they are comparatively expensive. The invention has for its object to provide an electric reflector lamp of the kind described in the opening paragraph which is easy to manufacture and which renders possible an increased luminous intensity of the beam generated during operation. According to the invention, this object is achieved in that the lamp has a tubular body with a first end portion which is fastened to the neck portion of the reflector body, and a second end portion which supports the lamp cap, the mounting member being held between cooperating surfaces of the neck portion and the tubular body. An advantage of the electric reflector lamp according to the invention is that the position of the mounting member, and thus of the electric light source, relative to the reflector portion is accurately determined. In addition, the neck portion of the reflector body may be chosen to be very short, while nevertheless the overall dimensions of the lamp may be chosen at will because of the presence of the tubular body. Since the neck portion is short, its width increases only very little in the direction of the reflector portion. It is also advantageous that the mounting member is enclosed between the neck portion and the tubular body. The mounting member requires no space in the neck portion laterally of the electric light source. The neck portion, accordingly, is allowed to be just so wide as is necessary for accommodating the electric light source. It is favourable when the light emission window is closed with a cover plate. Pollution of the inner surface of the reflector portion during operation is prevented then. An advantage of the reflector lamp according to the invention provided with a cover plate is also that the cover plate may be provided before the electric light source is mounted. The electric element may in fact be introduced into the reflector portion through the neck portion. Vapours emitted by an adhesive agent when the cover plate is being fixed can then freely escape through the neck portion. In a favourable embodiment, the neck portion and the tubular body have overlapping end portions. These are capable of centring the mounting member. They reinforce the coupling between the two parts. In a favourable modification, they have cooperating studs and grooves which lock them against relative rotation. The neck portion and the tubular body may be fastened to one another by means of an adhesive agent. The reflector portion may have a metal layer, for example, at its inner surface. The layer may be an aluminium, silver or chromium layer which has, for example, been vapour-deposited. Alternatively, a dichroic filter may be present which transmits IR radiation and reflects light. The tubular body may be made of synthetic resin, for example of polyether imide, of glass, of ceramic material, or of metal. The lamp cap may be fastened thereto by means of inward projections which enter cavities. The electric element may be an incandescent body, for example in an inert gas containing an halogen, for example in the form of hydrogen bromide. The element, however, may alternatively be a pair of electrodes in an ionizable medium. An incandescent body may be linear or, for example, M-shaped. An embodiment of the electric reflector lamp according to the invention is shown in the drawings, in which Fig. 1 shows a lamp in longitudinal section, Figs. 2a and 2b show a mounting member in elevation and in cross-section, respectively, and Figs. 3a and 3b are elevations of the reflector body and of the tubular body taken on the lines IIIa and IIIb in Fig. 1, respectively. In Fig. 1, the electric reflector lamp has a moulded glass reflector body 1 with a neck portion 6 and a reflector portion 2 which has a light emission window 4. A lamp cap 25 is connected to the neck portion. An electric light source 30 has an electric element 32 in a gastight lamp vessel 31, the electric element 32 being arranged inside the reflector portion 2. A mounting member 40 keeps the lamp vessel 31 fixed in the neck portion 6. Current conductors 27,33; 26,34 extend from the electric element 32 to contacts at the lamp cap 25. The lamp has a tubular body 10 with a first end portion 11 which is fastened to the neck portion 6 of the reflector body 1, and a second end portion 13 which supports the lamp cap. The mounting member 40 is held between cooperating surfaces 7, 12 of the neck portion 6 and the tubular body 10. The reflector body shown in the Figure has a window with a diameter of approximately 5 cm. The body has a vapour- deposited aluminium layer at its inner surface by way of mirror. The light source is a halogen incandescent lamp with a hard-glass lamp vessel filled with an inert gas, such as argon/nitrogen, containing hydrogen bromide. The tubular body 10 may be non-transparent, and possibly coloured. A non-transparent body prevents the emission of light in situ , although, indeed, the mounting member 40 already renders the emission of light practically impossible there. A diode 28 is included in one current conductor 27, 33. A cover plate 20 is fastened to the reflector body 1 with an adhesive agent, closing off the light emission window 4. Since the light source can be introduced into the reflector body from below, as seen in the Figure, the cover plate has been provided previously and fixed with an adhesive agent, for example an epoxy resin. Vapours released during curing could escape freely. The cover plate in the Figure has a light-distributing function. The neck portion 6 and the tubular body 10 have overlapping end portions 8 and 11, respectively, which comprise cooperating grooves 14 and studs 11 to lock them against relative rotation. A ceramic adhesive may be provided between the mounting member 40 on the one hand and the cooperating surfaces 7,12 on the other hand. Such an adhesive may also be used between the overlapping end portions 8,11. Very little material suffices for this, which promotes a quick curing and the release of no or very few volatile ingredients. The mounting member 40 (see also Fig. 2) may be so dimensioned that it is centred by the collar-shaped end portion of the tubular body. Alternatively, the kinks 41d at the tongues 41b may centre the mounting member in cooperation with a bevelled edge 15 of the tubular body. The mounting member shown is a substantially flat metal disc with an opening 42 for accommodating a seal 35 of the lamp vessel (Fig. 1), while resilient tongues 41a, 41b are present for holding on to this seal. The tongues 41a may cooperate with a profile 36 of this seal 35 in this case. Cooperating grooves 14 and studs 9 are shown in Fig. 3. The electric reflector lamp according to the invention is easy to assemble. The reflecting surface area 3 is relatively large as a result of the small opening therein. One of the factors causing this is the small length of the neck portion. In comparison with a conventional lamp of the same length and width, the said opening is 16% smaller, which results in a 7% larger reflecting surface area and in a 20% greater luminous flux when an identical electric light source is used.

Claims: An electric reflector lamp comprising: a moulded glass reflector body (1) with a neck portion (6) and a reflector portion (2) which comprises a light emission window (4); a lamp cap (25) connected to the neck portion; an electric light source (30) comprising an electric element (32) in a gastight lamp vessel (31), the electric element (32) being positioned inside the reflector portion (2); a mounting member (40) which keeps the lamp vessel (31) fixed in the neck portion (6); and current conductors (27,33; 26,34) which extend from the electric element (32) to contacts at the lamp cap (25), characterized in that the lamp has a tubular body (10) with a first end portion (11) which is fastened to the neck portion (6) of the reflector body (1), and a second end portion (13) which supports the lamp cap, the mounting member (40) being held between cooperating surfaces (7,12) of the neck portion (6) and the tubular body (10). An electric reflector lamp as claimed in Claim 1, characterized in that a cover plate (20) is fastened to the reflector body (1) with an adhesive agent, closing off the light emission window (4). An electric reflector lamp as claimed in Claim 1 or 2, characterized in that the neck portion (6) and the tubular body (10) have overlapping end portions (8,11 respectively). An electric reflector lamp as claimed in Claim 3, characterized in that the overlapping end portions (8, 11) have cooperating grooves(14) and studs (9) which lock them against relative rotation.

Inventors: FIELDS LARRY, VENICX CHRIS, FIELDS, LARRY, VENICX, CHRIS
Applicants: PHILIPS ELECTRONICS NV, PHILIPS ELECTRONICS N.V.
Application year: 1992
Main classification: H01J5
IPC codes: H01J61, F21S2, H01K7, H01J5