WO1997021327A1 - Dispositif ameliore pour demarrer des lampes fluorescentes - Google Patents

Dispositif ameliore pour demarrer des lampes fluorescentes Download PDF

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Publication number
WO1997021327A1
WO1997021327A1 PCT/IL1996/000168 IL9600168W WO9721327A1 WO 1997021327 A1 WO1997021327 A1 WO 1997021327A1 IL 9600168 W IL9600168 W IL 9600168W WO 9721327 A1 WO9721327 A1 WO 9721327A1
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WO
WIPO (PCT)
Prior art keywords
lamp
current
voltage
filament
starting
Prior art date
Application number
PCT/IL1996/000168
Other languages
English (en)
Inventor
Shimon Vainer
Zvi Vainer (Gregory)
Original Assignee
Shimon Vainer
Vainer Zvi Gregory
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shimon Vainer, Vainer Zvi Gregory filed Critical Shimon Vainer
Publication of WO1997021327A1 publication Critical patent/WO1997021327A1/fr

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/02—Details
    • H05B41/04—Starting switches
    • H05B41/042—Starting switches using semiconductor devices
    • H05B41/044—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes
    • H05B41/046—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes using controlled semiconductor devices

Definitions

  • the invention relates to lighting means. More particularly, the invention relates to fluorescent lamps, such as neon lamps. Specifically, the invention relates to a method and device for a fast and smooth start of fluorescent lamps.
  • Fluorescent lamps are widely used for all lighting purposes. They are characterised by the low power consumption, bright illumination, and low heat emission. However, fluorescent lamps are still suffering from some drawbacks that prevent their use from being more widespread. For example the production cost of a fluorescent lamp is higher than that of an incandescent lamp, as its structure is more complicated, and fluorescent lamps require special starting means, which further increases the cost.
  • starters suffer from several drawbacks such as: a. They are capable of illuminating the lamps after a relatively long"starting period", normally in the range of up to 2-3 seconds and typically about 2.5 seconds (this period being referred to hereinafter as the “starting period”, is the period from the first application of voltage to the lamp, until a stable illumination is obtained); b. They provide a stable illumination after a starting period which is accompanied by several annoying flashes; c.
  • the most common starters comprise of a glow switch element, the contacts of which tend to wear out fast, which frequently causes damage to the iamp, and shortens the life of the lamp tube.
  • a typical fluorescent lamp comprises of a tube tilled with argon or krypton gas, and mercury.
  • the interior surface of the tube is coated with a fluorescent powder, such as phosphor, which converts the ultraviolet light produced by the discharge, i.e., due to ionisation process of the gas, into a visible light.
  • the lamp further comprises at ieast one, and normally two electrodes serving as a cathode or an anode alternatively, as the lamp is normally operated by an alternating current (AC).
  • Each one of said electrodes comprises a filament, for starting an ionisation process of the gas.
  • the ionisation process is normally activated by providing heating current to one filament, while the other electrode T serves as an anode.
  • Electrons are emitted from the hot filament, ionisation process starts, and colliding electrons excite mercury atoms. This process is associated with ultraviolet and visible radiation, which when absorbed by the phosphor, is converted into a visible light. The visible light exists as long as voltage is provided to the lamp. Typically, the connection to each filament is made via two pins, extending from the interior of the tube to its exterior. Regardless of their structure, fluorescent lamps need control means for activating the above mentioned ionisation process of the gas, and thereafter keeping a stabilised arc.
  • a commonly used starter (switching device) of the prior art type is shown in Fig ] .
  • the fluorescent lamp 1 filled with gas 4 has four contact pins 5,6,7 and 8.
  • the two filaments 2, and 3 are located between two adjacent pairs of said contact pins, i.e. between pins 5 and 6, and between pins 7 and 8.
  • the starting device further comprises of a bi-metal component 1 1 , usually contained within a small plastic canister, and a current limiting inductor 9.
  • a glow discharge is created along the bi-metal contacts of the glow starter.
  • the contacts warm up and close, closing the starting circuit, and allowing a current to flow from terminal 10, through the current limiting inductor 9, via the first cathode tube filament 2, through the closed bi-metal component 1 1 and the second filament, and back to terminal 14.
  • the cathode filaments are warm enough to emit electrons, and a glow is seen in the two ends of the tube.
  • the starter-switch bi-metal contacts 12 and 13 open (because of the glow discharge, which previously caused the to heat and close, ceases when they touch, and they cool and open) and this stops the filaments preheating current flow, causing a collapse of the magnetic energy, stored in the core of the inductor (choke) ballast 9, and producing a high voltage pulse (600V- 1000V) across the fluorescent tube, sufficient to strike the arc, and set up the electric discharge through tube 4.
  • the process is repeated several times, normally 3 to 10 times.
  • the current through the tube gradually builds up, causing an increase of the current through the tube. ⁇ s this happens, the voltage across inductor 9 also increases, and the voltage over the tube falls.
  • the inductor is designed so, that when the tube and the inductor current rise to a value determined by the inductor design, the circuit stabilises, and a stable illumination is provided.
  • starters that have been suggested, were found to be expensive, cumbersome, or not effective. For example, some starting devices normally provide a reliable start, but they do not shorten the starting period, or do not eliminate the annoying flashes. Some other means include a transformer instead of the bi-metal element, but these means are heavy, large and expensive, and still provide unsatisfactory results. Other starting devices are also known, in which the duration of the start depends on the voltage level across the lamp, which in turn depends on the ionisation level in the lamp. Those devices do not prevent repeated starts as well.
  • Fig 1 illustrates a starting device according to the prior art
  • Fig 2 shows a block diagiam form of a device according to one embodiment of the invention
  • Fig 3 shows the device of Tig 2 in greater detail
  • Fig 4 illustrates one possible structure of the switching element, in which two transistors are connected in series and act as a switch
  • Fig 5 (a)-(d) illustrate signals over different points of the device, according to the embodiment of the invention shown in Fig 4 (a) Shows the AC voltage of the elect ⁇ cal power, (b) shows the signal over points a and b during the starting period, (c) shows the signal over the two electrodes of the lamp during the starting period and (d) shows the signal over the two electrodes of the lamp during normal illumination;
  • Fig. 6 shows another possible structure of the switching element, according to another preferred embodiment of the invention, in which a pulse generator is used.
  • Fig. 7 (a)-(d) show signals over different points of the device of Fig. 6 .
  • (a) Shows the AC voltage of the electrical main power
  • (b) shows the signal over points a and b during the starting period
  • (c) shows the signal over the two electrodes of the lamp during the starting period
  • (d) shows the signal over the two electrodes of the lamp during normal illumination;
  • the method according to the invention is characterised in that the lamp is heated by forced pulses of current, while high voltage is provided to the electrodes of the lamp between those current pulses.
  • the method therefore enables reduction of the starting period to a minimum, in the range of 0.1 of a second, with no repeated starts, or annoying flashes.
  • two devices based on said method are disclosed. These starting devices are simple, reliable, light weighted, cheap, comprise only electronic components, and are capable to light fluorescent lamps having any conventional structure, size, or gas composure.
  • Fig. 2 shows in a block diagram form a basic structure of a device for providing a fast and smooth start of a fluorescent lamp according to one embodiment of the invention.
  • the device basically comprises a current limiter 9 which is essentially the same as the one which exists in any conventional device, a rectifier such as a diode bridge 36, a charging unit 25, a switch controller 27, a switch 30 controlled by said switch controller 27, and an asymmetric current supplier 18 (the function and operation of the "asymmetric current supplier" will become apparent as the description proceeds).
  • the device durmg each half-cycle of the AC supply, i e 0 01 second in a 50hz network, the device provides the electrodes of the lamp one period of high voltage suppl ⁇ , followed by a pe ⁇ od of current injection (the term cui rent injection" when used herein refers to a short pe ⁇ od du ⁇ ng which a high amount of current is applied, i e a pulse of current)
  • cui rent injection when used herein refers to a short pe ⁇ od du ⁇ ng which a high amount of current is applied, i e a pulse of current
  • the frequency of change between said two periods of current and high-voltage is higher, and therefore the two periods are shorter In other words there are several high voltage periods and current injection periods in each half-cycle of the AC supply during the starting period
  • the closure of the main switch 20 connects the device to the main AC power supply, and the device is immediately activated
  • the mam AC voltage passes through the current limiter inductor coil 9, and rectified by the full wave rectifier 36 Switch 30, is controlled by the switch controller 27 and by the asymmetric current supplier 18, both supply current towards the control point 40 and produce some varied potential at this point, which is generally high at the beginning of the starting period, and is gradually reduced
  • the rectified signal from the diode bridge passes through resistor 1 also adds potential to point 40 and causes switch 30 to close when the potential is above a threshold point, and latei close to the end of the half-period, to open again Du ⁇ ng the closing state of the switch, current is provided to the lamp, and when the switch opens a short and high voltage pulse is provided to electtodes of the lamp, for the same reasons as heretofore discussed for the p ⁇ or art element Therefore, alternating periods of current injections, followed by high-voltage periods are applied to the lamp electrodes
  • the current pulses are applied to the lamp
  • Fig 3 shows a more detailed description of the device according to the invention
  • Numeral 30, which is symbolically marked as a switch refers to an element function of which may be carried out by a variety of known solid state switching components, such as by a thy ⁇ stor, a transistor, etc
  • element 30 may comprise several components
  • Fig 4 shows an example of element 30 in which two transistors in series produce a suitable switch, having two contacts a and b, and a control input c
  • Fig 6 shows another possible structuie for element 30, in which the switch is replaced by a pulse generator
  • the followmg description relates to two embodiments of the invention, wherein in the first one element 30 contains the structure of Fig 4 , and in the second one, it contains the structure of Fig 6
  • the closure of the main switch 20 initiates the follow mg process a
  • the current limiter 21 starts to gradually allow an increased current supply to the filament 22, and through the device (or more particularly, the tectifier 36), to the second filament 18
  • the current limiter is so designed as to gradually increase the current up to a value suitable to maintain a stable illumination at the end of the starting period, as long as switch 20 is ON b AC voltage is provided to a full wave rectifier 36
  • conditions exist to enable a closure of switching element 30 shortly after the beginning ofthe half-cycle, bv the provision of the signal coming to point 40 through resistor 19 These conditions exist as transistor 27 is essentially in a cut-off state at this stage
  • a signal through resistor 19 to the switch control point 40 causes the switch to close any time it passes a specific threshold level.
  • Said switch opens again at the end of the half-cycle when the voltage decreases below said threshold level. Simultaneously, capacitor 25 starts to accumulate charge through resistor 24, and as the voltage over the capacitor rises, more current passes through the base of transistor 27, and the potential at the switch control point 40 decreases. As the potential decreases, closure of switching element 30 occurs after a longer time from beginning of each half-cycle of the AC voltage.
  • a current injection is provided to the filaments when switching element 30 is closed, and this, as described, occurs in the earlier part of each half-cycle. Also, the reopening of the switch causes a high voltage pulse between the two electrodes of the lamp. Therefore, for a time span of one second there are 100 periods of current injections to the lamp, and 100 periods of high voltage. However, normally there is no necessity for 1 second, because the illumination process is much faster in the range of 0.1 -0.2 of a second, i.e. about 5-10 cycles.
  • Fig. 5 is a timing diagram describing signals over different components of the starter according to this embodiment of the invention.
  • Fig. 5 (a) shows the main AC supply
  • Fig. 5 (b) shows the voltage over points a and b during the starting period
  • Fig. 5 (c) shows the voltage over the lamp electrodes during the starting period
  • Fig. 5 (d) shows the voltage over the lamp electrodes after the starting period and during a stable illumination.
  • switching element 30 can be replaced by a miniature pulse generator.
  • the pulse generator as shown in Fig. 6 initiates pulses of at least several times the amplitude of the electric network.
  • the pulse generator is designed to provide several pulses during every half-cycle.
  • the frequency of the pulses is determined and controlled by the voltage level at point c. As in the previously discussed embodiment of the invention, this voltage level is determined by the operation of the switch controller 39, and by the asymmetric current supplier comprises of numerals 15 and 16.
  • the device as shown therefore provides high voltage pulses, which occur several times during each half-cycle.
  • Fig. 7 is a timing diagram describing signals over different components of the starter according to this preferred embodiment of the invention.
  • Fig. 7 (a) shows the main AC supply
  • Fig. 7 (b) shows the voltage over points a and b during the starting period
  • Fig. 7 (c) shows the voltage over the lamp electrodes during the starting period
  • Fig. 7 (a) shows the main AC supply
  • Fig. 7 (b) shows the voltage over points a and b during the starting period
  • Fig. 7 (c) shows the voltage over the lamp electrodes during the starting period
  • Fig. 7 (a) shows the main AC supply
  • Fig. 7 (b) shows the voltage over points a and b during the starting period
  • Fig. 7 (c) shows the voltage over the lamp electrodes during the starting period
  • Fig. 7 (a) shows the main AC supply
  • Fig. 7 (b) shows the voltage over points a and b during the starting period
  • Fig. 7 (c) shows the voltage over the lamp electrode
  • FIG. 7 (d) shows the voltage over the lamp electrodes after the starting period and during a stable illumination.
  • C indicates periods of current injections
  • V indicates periods of high voltage pulses.
  • the diagrams of Figs. 5 and 7 are just principle diagrams, and the signal may vary according to the adaptation of the device.
  • the device can light fluorescent lamps with no filaments at all. The condition of heat, which is needed during the starting period is provided by the spark. This fact can significantly simplify the structure of fluorescent lamps, reduce their production cost, improve their reliability, and extend their life duration.

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

L'invention concerne un dispositif et un procédé pour allumer une lampe fluorescente (1) connectée à une source de tension alternative (22, 23). Le dispositif, comprend un limiteur de courant (9) connecté à la source de tension alternative et d'une manière sérielle à un premier filament (2) de la lampe, un redresseur de tension (36) pour redresser le signal de tension alternative et pour fournir le signal de tension redressé à un second filament (3) de la lampe fluorescente (3), un moyen de commutation (30, 18, 19) commandé par un moyen d'horloge (34, 25, 27) pour couper périodiquement ledit signal redressé venant du second filament, et un moyen d'horloge pour commander l'activation du moyen de commutation. Le procédé consiste à fournir aux électrodes de la lampe, des impulsions de haute tension, suivies par des injections de courant au moins une fois durant chaque demi-cycle du courant alternatif du circuit électrique. De préférence, la fréquence des injections de courant augmente à mesure que l'on avance dans la période de démarrage, plusieurs impulsions de haute tension sont fournies à la lampe durant chaque demi-cycle et le nombre d'impulsions, durant chaque demi-cycle diminue à mesure que l'on avance dans la période de démarrage.
PCT/IL1996/000168 1995-12-04 1996-11-26 Dispositif ameliore pour demarrer des lampes fluorescentes WO1997021327A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL116250 1995-12-04
IL11625095A IL116250A0 (en) 1995-12-04 1995-12-04 Improved starting device for fluorescent lamps

Publications (1)

Publication Number Publication Date
WO1997021327A1 true WO1997021327A1 (fr) 1997-06-12

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Application Number Title Priority Date Filing Date
PCT/IL1996/000168 WO1997021327A1 (fr) 1995-12-04 1996-11-26 Dispositif ameliore pour demarrer des lampes fluorescentes

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WO (1) WO1997021327A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4177403A (en) * 1977-01-31 1979-12-04 U.S. Philips Corporation Electronic starter for igniting a discharge lamp
US4503359A (en) * 1979-09-12 1985-03-05 Hitachi Lighting, Ltd. Discharge lamp lighting device
US4629944A (en) * 1983-03-03 1986-12-16 Texas Instruments Incorporated Starter circuit for a fluorescent tube lamp
US4746841A (en) * 1985-07-10 1988-05-24 Hitachi, Ltd. Fluorescent lamp operating device
US5373215A (en) * 1993-07-07 1994-12-13 The United States Of America As Represented By The United States Department Of Energy Ionization tube simmer current circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4177403A (en) * 1977-01-31 1979-12-04 U.S. Philips Corporation Electronic starter for igniting a discharge lamp
US4503359A (en) * 1979-09-12 1985-03-05 Hitachi Lighting, Ltd. Discharge lamp lighting device
US4629944A (en) * 1983-03-03 1986-12-16 Texas Instruments Incorporated Starter circuit for a fluorescent tube lamp
US4746841A (en) * 1985-07-10 1988-05-24 Hitachi, Ltd. Fluorescent lamp operating device
US5373215A (en) * 1993-07-07 1994-12-13 The United States Of America As Represented By The United States Department Of Energy Ionization tube simmer current circuit

Also Published As

Publication number Publication date
IL116250A0 (en) 1996-03-31

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