DE8904853U1 - Fluorescent lamp - Google Patents

Description

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Fluorescent lamp

The innovation relates to a fluorescent lamp according to the generic term of the main claim.

According to DE-PS 27 25 ¹ 112 and US-PS 36 09 **36, as well as US-PS 20 01 501, GB-PS 518 201 and DiS -PS 26 35 57*J, it is known to arrange additional straight or U-shaped discharge tubes in the interior of fluorescent lamps and to equip these with several discharge electrodes. According to DE-PS 27 25 412, it is also known to provide the outer wall of the discharge tube with a phosphor layer over half its circumference and its entire length. The lamps according to these publications are small, have a threaded connection base, and the discharge takes place in the inner discharge tube and in the lamp bulb. The electrical discharge in the inner discharge chambers initially generates UV radiation, which is converted into visible light in the phosphor layer. The UV radiation generated in the inner discharge tube, however, only contributes to a small extent to the generation of visible light, which is ultimately emitted from the surface of the lamp bulb into the environment. For this reason, the light yield or efficiency of such lamps is relatively low. The electrical energy required for the discharge in the inner discharge tube alone amounts to approximately 50% of the total energy consumption, and in the end

These 50% only contribute about 10% to the total light output of the lamp. Another disadvantage of the previously known lamps is the difficulty of obtaining the right balance of light distribution on the surface of the lamp. The large number of discharge electrodes required for lamps of this type is another economic disadvantage. In addition, a complicated and therefore expensive electrical circuit is required to control the electrodes.

The state of the art also includes lamps that are known in the literature as "compact lamps". From the OSRAM Company's Technical and Scientific Paper, 1986, Volume 12, pages 383 to 393, it is known that these "compact lamps" are equipped with built-in control devices and a threaded base and that they operate at higher frequencies of the lamp current. The advantages of compact lamps, compared to the small lamps described in the above-mentioned documents, are their even smaller dimensions, improved lamp efficiency and reduced light flickering. Despite the advantages of these "compact lamps", they are splitters and their light output is still relatively low.

The innovation is intended to improve the efficiency of such fluorescent lamps and to

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with the aim of further reducing the manufacturing costs of such lamps.

Task int mil. &eegr;&iacgr;&eegr;&tgr; I, eunlit.nl", &eegr; VV I ainpe of the one ng·-'up;&eegr; ii &Lgr;rl", iwli of the innovation by^h dip In knowledge in nhen i|pfi main claims &eegr;dk·" ¹ for I °n features Rel.öp!.. V'ii l.cilhafte Wo I t orb i I duuren and practical Ann ition forms arise

['"In function of the Hispr &idigr; nz in &rgr;&Iacgr;&tgr; new lamp there are two r.iip in the non-circular shape of the Inn I, i ?r 1° &eegr; Jöl· I &igr;- i &pgr;&eegr; lic unfortunately toRruruln. Par» ernle F^'-l er. ¹ ?'.rect, .^icb in the known manner ^wi.snli two Fn' ! adtniRP" I «=k !.roden in the Fnt I adnngsrfi'im uikI the two d» field extends from the interior to the interior element perpendicular to the »rf»te.

The economic advantage of the new type of fluorescent lamp is the significantly higher light output per unit of uncontaminated electrical energy compared to the light output of known fluorescent lamps. The achievable efficiency of the fluorescent lamp according to the invention is approximately twice as high as the efficiency of known fluorescent lamps that are operated at 50 Hz. Furthermore, according to the invention, the efficiency of the lamp is approximately 1.6 times higher than the efficiency of known so-called "compact lamps" that are operated at approximately 35 kHz. A further advantage is the homogeneous light distribution _that occurs on the surface of the lamp.

This results in a reduction in the cost of the lamp bulb, and furthermore the ballasts which are suitable for both electrical fields ^are easy to manufacture and cheaper than the ballasts of known manufacturers. In comparison to conventional ballasts , this means that the ballasts are easy to manufacture and cheaper than the ballasts of known manufacturers ^. &rgr;,&ggr;·&rgr;&pgr;&igr;&pgr;&Igr;-"&Iacgr; Hp rate I 1 .ungakoR Leu r|r·»· erfi.nrlungspeinäPien Leunlihftnf'f l.ampe In packaging 1 ei.oh to those known-1.91' lamps significantly reduced &bgr;&idigr;&igr;&kgr;&idigr;.

I.Vi. a further I,mich I;..^ tn f f'I.Rmpn is explained in more detail below using the following illustrated examples.

Ka shows schematically

Fig. 1 partially in section and view of the tube-shaped fluorescent lamp according to the invention;

Fig. 2 is an enlarged section through the lamp along line TI-II in Fig. 1;

Fig. 3 shows in section one end of the inner element of the fluorescent lamp according to Fig. 1;

Fig. ¹ JA partly in section and view the fluorescent lamp in bulb form;

Fig. i)B shows a special embodiment of the inner element in section;

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Fig. ? the graphical representation of the potential gradients as a function of ^\ev lamp current density;

Fig. G the graphical representation of the lamp voltage on the capacitor plate as a function of time and

Fig. 7 shows the graphical representation of the power output as a function of time.

The fluorescent lamp according to Fig. 1, ?. and 3 consists of a tubular lamp bulb 1 and a discharge space 3 delimited by this and the inner element ? , the inner wall of the lamp bulb 1 being covered with a phosphor layer ?. The discharge space 3 is filled with mercury vapor and with a noble gas or with a noble gas mixture. Thermally emitting discharge electrodes J and 8 are arranged in the discharge space 3 at both inner ends of the lamp bulb 1, between which the electrical discharge takes place in the discharge space 3. The outer surface of the inner element 2 is also covered over its entire length with a phosphor layer 9 or coated with a UV radiation reflector. The inner element 2 is arranged concentrically to the longitudinal axis of the lamp bulb 1 in such a way that its outlet 10 is connected to the inner ends of the bulb 1 in a gas-tight manner and in this way is integrated into the bases 5, 6 together with the lamp bulb 1. The inner element 2 consists of a

Glass tube like the lamp bulb I, ⁿ s Now also at's materials can be made, dip have the same or similar properties as Glan or dip the same l ^r &ugr;&eegr; k 11 &ogr;&eegr; er &Ggr;' MI e &eegr; .

This inner conductor with 2 hai. "ine more f'nHie &Igr;&rgr;'&Iacgr;&igr;&igr;&igr; i sch« and physical ped"ui.iMi»> . rr?!=n.~ !■•-grruz t &udigr;&pgr;.°, &iacgr; The discharge element 2 forms the discharge chamber " ¹ " which, as can be seen from Fig. 1, is in cross-section through the body ring InL. 7. Furthermore, the inner I is a carrier of the two continuously emitting electrodes ⁰ ! 7 and B. Fig. 3 shows that the electrodes are gas-tight according to known methods at the discharge K, i.gt and are connected to the mains voltage by means of a series circuit via terminals 17 and 1B ^. The electrode ⁷ (see Fig. I) at the other end is connected in the same way. Thirdly, in the inner space 11 of the inner element 2, as can be seen in Fig. 1 , one or more metal plates 12 are arranged, which are connected to a voltage source by lines 15 or 16. The voltage source is arranged in the longer base G, but is not shown in detail. The metal plate 12 (Fig. 3) can be made of a sheet, a sieve, a metal layer or the like and forms a capacitor plate. Fig. 1 and Fig. 2 also show, for example, that this capacitor plate can also consist of fine metal chips or of "aluminum wool" 13 or of a grid 1U, with which the interior of the inner element 2 is simply filled.

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These elements are capacitor plates because they are in a charged state when the lamp is in operation. The electrically conductive plasma in the discharge space 3 forms the second electrical conductor of an electrical capacitor. An insulating material formed by the wall of the inner element 2 is arranged between the charged conductors. An electrical field oscillates in this electrical capacitor, which emanates from the voltage source arranged in the base 6. According to Fig. 3, current from the heated electrode 8 flows through the lines 17 and 18 to the cloth between the electrodes 7 and 8, which simultaneously forms the lamp or discharge current.

The fluorescent lamp in Fig. 1 looks like known fluorescent lamps, except that the lamp caps fit into the known sockets, ie no changes are required to the known sockets. The length of the lamp according to Fig. 1 can be between 150 mm and 2370 mm as required and the diameter of the lamp bulb 1 can be between 30 and 55 mm. The distance IJ between the inner wall of the lamp bulb 1 and the outer wall of the inner element 2 can be, for example, 5 to 13 mm.

Fig. 'IA and 'IR' show a so-called compact lamp, which is equipped with ballasts built into the base 6' and is provided with a threaded base 19 and thus can be fitted into conventional filament lamps.

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lamp casings. The capacitor plate 20 extends over the entire length of the inner chamber 11' of the inner element 2' and is advantageously made of a metal ligature which is simply pushed into the glass tube during the manufacture of the inner element 2'. The electrical line 22 connects the grid 20 to the voltage source _; which is located in the base 6'.

Another embodiment of the inner element 2' is shown in Fig. 1B. In this case, only a thermally emitting discharge electrode 8" is provided on the inner element 2" at the outlet 10', and at the other end of the inner space 11'' a short capacitor plate 21 is arranged, which is connected by the line 23' to the voltage source located in the base ^61. The second pole of the voltage source is connected to the electrode 0" via the line 23'; and the electrical circuit between the capacitor plate 21 and the plasma in the discharge space 3' is closed by the wall of the inner element 2". The length of the lamp according to Fig. 1B is, for example, 150 mm to 250 mm and the outside diameter of the lamp bulb 1' is 30 mm to 60 mm.

The interior space 11·, 11" of the inner element 2', 2" is not sealed off from the atmosphere, which also applies to the interior space 11 of the inner element 2 of the lamp according to Fig. 1. All lines of the lamp according to Figs. I and Λ are located in the interior space 11, 11', 11" of the inner element 2, 2 ¹ , 2".

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Depending on the required lamp power and the overall geometric and electrotechnical parameters of the lamps, it must be decided whether only one capacitor plate 20 (Fig. 'la) or two separate capacitor plates 12 (Fig. 3) or only one capacitor plate 21 (Fig. MB) is to be provided. This depends on the frequency of the voltage applied to the capacitor plates 12, 1', 20 or 21, as well as on the distance φ between the inner element 2 and the lamp bulb 1. If the distance D is small, the frequency of an electrical voltage on the capacitor plates must be higher than with a larger distance D.

The luminous efficacy of the fluorescent lamp is inversely proportional to the distance D between the inner element 2 and the lamp bulb 1, i.e. if the distance D is reduced, the luminous efficacy of the lamp increases and vice versa. A second parameter which improves the efficiency of the lamp is the frequency of the voltage applied to the capacitor plates 12, 13, ¹¹ , 20 and 21. A third important parameter for improving the efficiency of the lamp is the pulse duration of a so-called monopolar electrical pulse which is applied to the aforementioned capacitor plates. If the pulse duration is shorter, i.e. if the rise time of the pulse is shorter, then the efficiency of the fluorescent lamp is greater. The rise time of this pulse is the most important physical parameter on which the dpi* efficiency of the lamp depends.

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The lamp according to Fig. 1 is connected in a known manner to the usual mains voltage of 50 Hz. After ignition, the lamp current flows between the electrodes 7 and 8, and at the same time the voltage of the capacitor plate 13 or IM acts perpendicularly on the lamp current through the Wn;v ^! of the inner element 2. This vertical voltage increases the electrical resistance of the plasma located in the discharge space 3. The resistance of the plasma 3 increases proportionally with this vertically oriented voltage, mainly when the current density of the lamp current in the plasma is greater. This physical phenomenon controls the homogeneity of the electrical current in the entire discharge space 3. If, for example, the current density in a locally limited small space increases faster than in an adjacent space, then the electrical resistance in the space with rapidly increasing current density increases rapidly under the effect of the vertical voltage, which slows down the increase in current density in this limited space. The end result &igr; This results in a homogeneous current density in the entire discharge space 3. The unit of the current density defined here is milliamperes per square millimeter δηλ/παγια ² ). A homogeneous current density in the discharge space 3 guarantees a homogeneous light distribution of the visible light on the surface of the lamp bulb.·? 1.

^Furthermore , the resistance of the plasma in the charge space 3 is dependent on the distance I. If the distance I between the walls 1 and 2 becomes smaller, the resistance dps P increases. for· resistance of the plasma pr" /,ent in^ter the· RnL iadurigslänge is, of the PnLrMi in Fig. ^r > loinlit ei-rn<:hr>ni).i &igr; . I) i &rgr; SparnnniR in ^! 'm1(, |&eegr;·&pgr;7,enl". i inel-er (V/hiii) dnr Lamppn.l än^e , also Poland I prad i °!iL RenannL, in L on the<=M· vertical axis in Fig. ^r i au Tg« ³ führ-L and din , ^r ;i lomd i ohl-p fm A/mm) dpi &Igr;..-unpensLrr)rne3 on the^r liorJ.7.r)iiLa.l. ^p n Aelise. All the data in Fig. 5 have been measured without a right-angled voltage. For each curve in ^Fig . 7, the slope i L of the (V/γμπ) from (π/λίδα ^? ) bp\. and the distance P for the curve 1 is (\^r distance \) - M Mim, for curve P is ρ ₌ 10 mm, for curve 3 is P = 8 mm and for curve λ is the ^distance U = 5 mm.

The largest potential /' ¹ qdlpnttMi is exhibited by a lamp with a distance I) = "3 mm, while a lamp with a distance ^PrM mm has the smaller potential tia I.gradj. The patterns in Fig. 5 change considerably when an insulating voltage with a short pulse duration is applied to the capacitor plates i3, 1μ. It is advantageous ^if the vertical voltage consists of short-duration pulses and if the frequency of the pulses is high. All known high-frequency generators can be used for generating the vertical voltage, whereby the most suitable are those which generate pulses whose rise time is in the range of nanoseconds (I = 10" sec.).

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A small frequency pulse generator according to IjR -OS 37 06 305 was installed in the cell 6.6'. The frequency of the innopolar pulses generated by this method can be adjusted over a wide range. The polarity of the pulses is the same as the polarity of the mains voltage.

Fig. 6 shows a graph of an oscilloscope which has a monopolar pulse P in half a period of mains voltage of ^r >0 Hz. The pulse voltage (V) is given on the vertical axis and the time in milliseconds (ms) is given on the horizontal axis. These pulses P are applied to the capacitor plates ' 3 , '" in Fig. 1 or 22, 2\ in Fig. 6. ^Fig . 7 shows schematically some further graphic representations of the distribution of the lamp voltage in the discharge chamber 3 or 3' which are shown under &Lgr;^v. Effect of the pulses P between the voltage V and Vp simultaneously ^with the pulse P. A higher frequency of the pulses P than the frequency shown in Fig. 6 naturally produces a higher oscillation of the lamp voltage in the discharge space 3. The oscillating vertical voltage P on the capacitor plates produces an oscillation of the plasma in the discharge space 3. This oscillation of the plasma is independent of the frequency of the discharge current flowing between the electrodes 7 and 8. Any known high - frequency generator which is connected to the capacitor plates mentioned leads to an oscillation of the plasma in the discharge space 3 and thus significantly improves the light output of such lamps.

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The attached table shows the luminous efficacy in lumens per watt (Im/W) for lamps with a spacing U of 5 mm and D of 8 mm at different electrical energies operated at 50 Hv. through the electrodes 7 and B into the discharge space " i.length 1 M. and onifi' of the energy that l> ^D i ca. 35 kllz is conducted through the capacitor plates 12, 13, ' ¹ I, ?", ?\ in a time i,Mii(>M. ".-pw. zri ?-;!■. Column 2 of the table shows that the electrical energy at 50 Mz is B'! % and the electrical energy at. 35 kllz I? /-. The Li cli I nusbe ter of the lamp according to Fig. I with a distance of I) = 5 mm I then has 157 Im/W and with. a distance of D - 8 mm 128 Im/W. The figures in columns 3 and 4 contain the efficiency ^r \e\' Lamp be-, other energy relies I tu i ssen .

The example in column I illustrates the luminous efficacy of a lamp without a high frequency generator, whereby only a voltage of 50 Mz was applied to the capacitor plate 13 or im. The luminous efficacy with such a simple electrical circuit of the lamp in Fig. 1 is 93 lumens per watt.

The data in the table clearly show that expensive high frequency generators are saved because the electrical energy of the high frequency only accounts for a small proportion of the total electrical energy. For example, with a lamp output of 30 W, only about 8 W of the electrical energy is used at 35 kHz and about 22 W at 50 Hz. Such a lamp radiates with about 600 lumens.

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The light output of the compact lamp as shown in Fig. 1 is approximately 1.0 times greater than that of the known compact lamps.

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Claims (1)

(16 172) Protection claims: 1. Fluorescent lamp with a discharge space delimited by the lamp body, which contains discharge electrodes (7, 8), the entire inner wall of the lamp body (1, 1') being covered with a phosphor layer (*!), characterized in that in the inner wall of the lamp body (1, P) there is an inner element extending along the lamp body. (2, 2' _t 2") is arranged, which with its outer wall (2, 2', 2") and the inner wall of the lamp body (1, 1') delimits the discharge space (3, 3'), wherein on the inner wall of the inner element (2, 2', 2") at least over part of its total length electrically conductive material is arranged, which is connected by lines (15, 16, 22, 22', 23,23') to a voltage source and ballasts and wherein furthermore the interior (11, ¹¹ ', 11") of the inner element (2, ²¹ , 2") is sealed gas-tight against the discharge space (3). 2. Fluorescent lamp according to claim I,
characterized in that the discharge detectors (7, 8) are arranged in a gas-tight manner at both ends of the outer wall of the inner element (P, 2") in the vicinity of the outlet (10, 10'), which are connected to voltage sources and ballasts via lines (17, 18, 23). &bull;&bull;I·· ■■ · ·· · · 3* Fluorescent lamp according to claim 1, characterized in that a discharge electrode (8") is arranged in a gas-tight manner at one end of the outer wall of the inner element (2") near the outlet (10') and a capacitor plate (2t) is arranged at the other end of the inner wall of the inner element (2"), which is connected to a high-frequency generator by a line (P.?.') . A fluorescent lamp according to any one of claims 1 to 3, characterized in that the interior of the inner ^element (2) is filled over at least part of its entire length with electrically conductive material (13), such as aluminum wool, fine metal chips, metal powder, and is connected to a voltage source and ballasts by a line (15, 16). 5« Fluorescent lamp according to one of claims 1 to 3, characterized in that a grid (16, 20) is arranged on the inner wall of the inner element (2, 2') over at least part of its entire length and is connected to a voltage source and ballasts by a line (22). 6. Fluorescent lamp according to one of claims 1 to 5, characterized in that the electrical reveals (15, 16, 17, 18, 22, 22', ^3» 23') are arranged in the interior (11, 11*, 11") of the inner element (2, 2', 2").