Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01K—ELECTRIC INCANDESCENT LAMPS
  • H01K1/00—Details
  • H01K1/28—Envelopes; Vessels

Definitions

• the invention is based on an incandescent lamp, in particular a halogen incandescent lamp with an IR reflection layer, according to the preamble of claim 1.
• This type of lamp is used in general lighting as well as for special lighting purposes, in combination with a reflector, for example in projection technology.
• IR layer for short - The rotationally symmetrical shape of the lamp bulb in conjunction with a coating reflecting IR radiation applied to its inner and / or outer surface - hereinafter referred to as IR layer for short - causes a large part of the IR radiation power emitted by the luminous element to be reflected back.
• the increase in lamp efficiency achieved in this way can be used, on the one hand, with constant electrical power consumption for a temperature increase in the filament and consequently an increase in the luminous flux.
• a predetermined luminous flux can be achieved with lower electrical power consumption - an advantageous "energy saving effect".
• Another desirable effect is that, owing to the IR layer, significantly less IR radiation power is emitted through the lamp bulb and the environment is thus heated than in conventional incandescent lamps.
• the power density of the IR radiation components within the lamp bulb decreases with the number of reflections and consequently also the efficiency of the incandescent lamp. It is therefore crucial for the actually achievable increase in efficiency to minimize the number of reflections required for returning the individual IR rays to the luminous element.
• the lamp bulb provided with the IR layer is specially shaped.
• Corresponding helix shapes can only be realized to a very limited extent due to the limited ductility of the tungsten wire that is generally used for this.
• a cube-shaped helix is suggested as a rough but practical approximation for a sphere.
• the helix has the largest diameter in its center. This gradually decreases towards the two ends of the helix.
• it is proposed to arrange a luminous element in each of the two focal points of the ellipsoid.
• EP-A 0 470 496 discloses a lamp with a spherical bulb, in the center of which a cylindrical luminous element is arranged. This document teaches that the loss of efficiency can be limited to an acceptable level by the deviation of the filament from the ideal spherical shape under the following conditions. Either the bulb diameter and filament diameter or length must be carefully coordinated within a tolerance range, or the diameter of the filament must be significantly smaller (small factor 0.05) than that of the lamp bulb. In addition, a lamp with an ellipsoidal bulb is specified, in the focal line of which an elongated luminous element is arranged axially.
• DE-OS 30 35 068 specifies a teaching for minimizing the inevitable aberration losses even in the latter embodiment. Thereafter, the two focal points of the ellipsoidal lamp bulb lie on the axis of the cylindrical luminous element and at predetermined distances from its respective ends.
• EP-A-0 765 528 discloses a halogen incandescent lamp with a lamp bulb which is shaped as an ellipsoidal or ellipsoid-like barrel body and is provided with an IR layer.
• the ellipsoidal or possibly ellipsoid-like part of the contour of the barrel body is generated by an ellipse section, the small semi-axis b of which is arranged perpendicular to the longitudinal axis of the lamp, ie the axis of rotation of the lamp bulb.
• the small semi-axis of the generators is smaller than half the bulb diameter D / 2 and is displaced approximately by the radius d / 2 of the filament parallel to the axis of rotation, which ultimately results in the barrel body.
• the length of the luminous element corresponds approximately to the distance between the two focal points of the generating ellipse section.
• the filament is positioned within the lamp bulb so that - in the representation of a longitudinal section - the two focal points with the two corresponding corner points of the filament approximately coincide. However, this heats the filament unevenly.
• Another disadvantage of this solution is that the improvement in lamp efficiency that can be achieved depends relatively strongly on the dimensioning and positioning of the filament within the lamp envelope.
• the invention has for its object to eliminate the disadvantages mentioned and to provide an incandescent lamp which is characterized by an efficient return of the emitted IR radiation to the luminous element and consequently a high degree of efficiency.
• compact lamp dimensions with high luminance levels should be made possible, as is sought in particular for low-voltage halogen incandescent lamps.
• FIG. 1 shows a schematic representation of the basic relationships and introduces some parameters that are essential for understanding the invention.
• an ellipse 1 is shown with the large and the small semiaxis a and b as well as with the two focal points F 1 and F 2 .
• the contour of the rotationally symmetrical lamp bulb 2 (shown in a highly schematic and simplified manner) is essentially generated by an ellipse section 3 (highlighted in FIG. 1 by a larger line width) of the ellipse 1.
• the contour can therefore be simplified describe by the rotation of the ellipse section 3 about an axis of rotation RA.
• the ellipse section 3 is specifically selected so that, firstly, the small semiaxis b is oriented perpendicular to the axis of rotation RA of the lamp bulb 2 and, secondly, that the small semiaxis is longer than the radius R of the lamp bulb 2.
• the lamp bulb 2 no longer has the shape of a "real" rotational ellipsoid.
• a luminous element 4 with a rotationally symmetrical, for example circular cylindrical, outer contour (shown as a rectangle in the schematic longitudinal section in FIG. 1) is arranged centrally axially inside the lamp bulb 2.
• the focal axis F 1 F 2 - that is the connecting straight line of the two focal points F 1 , F 2 within the lamp bulb 2 - is displaced parallel to the axis of rotation RA of the lamp bulb 2, specifically in the direction away from the generator 3.
• the length of the small semi-axis b is selected from the range R ⁇ b ⁇ R + 5 ⁇ w r , in particular from the range R + w r b b ⁇ R + 3w r .
• R and w r denote the largest radius of the lamp bulb or the radius of the cylindrical or cylinder-like filament.
• a seal for example a pinch seal or fusible seal, must be provided on the one or both sides in the region of the axis of rotation for the current lead-through (not shown in FIG. 1 for the sake of a better overview).
• the side of the piston opposite the current feedthrough is usually shaped like a dome and may optionally also have a pump tip (likewise not shown in FIG. 1, but compare FIG. 3).
• Figure 2a corresponds essentially to the conditions in DE-OS 30 35 068. It shows an ellipsoidal lamp bulb 5, in the interior of which a luminous element 6 is arranged axially in the center such that the two focal points F 1 and F 2 of the ellipsoid of revolution with the ends of the filament 6 coincide.
• the focal axis is consequently arranged colinearly with the axis of rotation RA of the lamp bulb 5, in contrast to the present invention.
• Figure 2b finally shows the conditions in EP-A-0 765 528.
• the lamp bulb 7 is shaped as an ellipsoidal or ellipsoidal barrel body.
• the schematic sectional illustration shows two ellipse halves which are connected to one another by means of two straight sections.
• the focal pairs F 1 , F 2 and F 1 ', F 2 ' of the two ellipse halves coincide with the corner points of the luminous element 8.
• the focal axis F 1 F 2 is displaced parallel to the axis of rotation RA, but - in contrast to the present invention - towards the generatrix.
• An advantage of the present invention is - apart from the increase in efficiency - the likewise increased uniformity with which the IR radiation is reflected back onto the coil. This prevents local overheating, which can lead to premature destruction of the coil. It is also advantageous that the achievable improvement in lamp efficiency compared to EP-A-0 765 528 depends less on production-related fluctuations in the positioning of the filament within the bulb.
• Axially arranged single or double filaments made of tungsten are used as the filament.
• the luminous element is connected in an electrically conductive manner to two power supply lines, both of which are routed gas-tight to the outside either together at one end of the lamp bulb or separately at the two opposite ends of the lamp bulb. Sealing is generally done through a pinch. Another closing technique is also possible, e.g. a melting plate.
• the version closed on one side is particularly suitable for NV and MV (medium-voltage) applications. In this case, very compact lamp dimensions can be achieved due to the relatively short illuminants.
• the largest possible part of the bulb wall can be used as an effective reflection surface.
• the lamp bulb has a lamp neck at one or possibly at both ends in the area of the current leadthrough.
• the lamp neck surrounds the current feedthrough as closely as possible and merges into a seal. Details can be found in EP-A-0 765 528
• the lamp bulb is usually filled with inert gas, for example with N 2 , Xe, Ar and / or Kr.
• inert gas for example with N 2 , Xe, Ar and / or Kr.
• halogen additives which maintain a tungsten-halogen cycle in order to counteract blackening of the bulb.
• the lamp bulb is made of a translucent material, such as quartz glass.
• the lamp can be operated with an outer bulb. If a particularly strong reduction in the IR power emitted into the surroundings is desired, this can also have an IR layer.
• the IR layer can be designed, for example, as an interference filter known per se - usually a sequence of alternating dielectric layers of different refractive indices.
• the basic structure of suitable IR layers is e.g. explained in EP-A 0 470 496.
• a lamp 9 is shown schematically. It is a halogen incandescent lamp with a nominal voltage of 120 V. It consists of a lamp bulb 10 squeezed on one side, which is shaped as an ellipsoid-like body.
• the generatrix of the ellipsoidal partial contour of the lamp bulb 10 is an ellipse section, the small semiaxis of which is 8.2 mm long and oriented perpendicular to the longitudinal axis of the lamp 9.
• the large semi-axis of the generators is 9.3 mm long.
• the lamp bulb 10 is made of quartz glass with a wall thickness of approximately 1 mm and has a largest outer diameter of approximately 15 mm.
• the lamp bulb 10 goes into one Neck 11 over, which ends in a seal 12. At its opposite end it has a pump tip 13.
• a luminous element 15 is arranged axially centrally within the lamp bulb. It has a length of 9.7 mm and an outer diameter of 1.25 mm.
• the luminous element 15 is made of tungsten wire and is held by means of two power leads 16, 17 leading through the seal 12 to the outside.

Landscapes

• Vessels And Coating Films For Discharge Lamps (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Discharge Lamps And Accessories Thereof (AREA)
• Optical Elements Other Than Lenses (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7817814

Family Applications (1)

Country Status (10)

Families Citing this family (10)

Family Cites Families (10)

• 1997
  • 1997-01-20 DE DE19701792A patent/DE19701792A1/de not_active Withdrawn
  • 1997-12-30 TW TW086119963A patent/TW360895B/zh not_active IP Right Cessation
• 1998
  • 1998-01-19 CA CA002249374A patent/CA2249374C/en not_active Expired - Fee Related
  • 1998-01-19 DE DE59809533T patent/DE59809533D1/de not_active Expired - Lifetime
  • 1998-01-19 CN CNB988000482A patent/CN1146014C/zh not_active Expired - Lifetime
  • 1998-01-19 US US09/142,579 patent/US6160341A/en not_active Expired - Lifetime
  • 1998-01-19 WO PCT/DE1998/000149 patent/WO1998032157A1/de active IP Right Grant
  • 1998-01-19 JP JP53352798A patent/JP4223563B2/ja not_active Expired - Fee Related
  • 1998-01-19 KR KR10-1998-0707060A patent/KR100420874B1/ko not_active IP Right Cessation
  • 1998-01-19 HU HU0000469A patent/HU223239B1/hu not_active IP Right Cessation
  • 1998-01-19 EP EP98906822A patent/EP0891628B1/de not_active Expired - Lifetime

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