JPH04223095A - Bias system for reducing lamp-contained ion loss and ion loss preventive method - Google Patents

Abstract

PURPOSE: To provide a high intensity luminescent lamp, having an AC electric source for a chamber to form a plasma conductor for light emission. CONSTITUTION: A DC electric potential is generated as a DC circuit means 28 is distributed with electric power from an AC supply circuit 20, and this electric potential is added to elements of a comparatively large area near a plasma chamber to restrain movement and loss of plasma particles by confining them in a chamber 16. The large area elements such as a reflector 18, an electric conductive housing 17, a reflector or a door 12 are properly polarized, and an electric field to prohibit movement of the plasma particles is generated. Consequently, color output and light output are improved, and lamp longevity is extended.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD This invention relates to luminaires and ballast techniques for minimizing the loss of plasma material and ions from the live plasma confinement arc tube in high intensity luminescent lamps.

0002

BACKGROUND OF THE INVENTION Sodium ions in high pressure sodium (HPS) lamps and ions of other elements in other types of lamps are lost through the walls of an arc containment means that confines the ionized gas at live operating conditions. This has been known for a long time.

0003

The basic problem has been described in various documents as well as in prior patents. In order to form and maintain the ionized plasma conductor that produces the light output in the lamp, it is necessary to place a metal, such as sodium, in the lamp and evaporate it into a gas-emitting state. Each type of lamp requires a fill or starting gas, a certain amount of metals, halides, and amalgams, and a specific partial pressure, so that the light output has the desired color spectrum and lumen level when subjected to the appropriate energy. and a mixture of elements activated with. As plasma material escapes from the lamp as ion losses, the characteristics of the lamp deteriorate, resulting in color shifts and reduced lumen output levels, causing it to no longer operate at the desired design and operating characteristics. Furthermore, the useful life of the lamp is significantly reduced as lamp performance is reduced and the lamp operating pressure is increased resulting in undesirable operating changes.

Although various proposals have been made to reduce such losses, no practical effective or economical solution has been found. Sodium loss is one of the major causes of high brightness luminescence performance degradation with operating time.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrical system that reduces the loss of gas ions from the lamp structure in a luminaire.

It is a further object of the present invention to provide a simple and inexpensive circuit that can be used and operate effectively in various types of ballast tubes and lighting fixtures.

Briefly stated, the present invention provides an electrical system for preventing ion loss from plasma conductors in high intensity light emitting lamps. The lamp includes an arc tube chamber containing an ionizable fill gas and a plasma material, such as a metal halide, which when vaporized helps form a plasma conductor upon emission of light, and has a first terminal and a second terminal. First circuit means including a ballast resistive element provides an AC operating voltage to the chamber. A conductive surface substantially surrounds and encloses the chamber. Second circuit means having a negative terminal and a positive terminal are connected to a voltage source for generating a DC potential. Third circuit means connects one of the DC output terminals to one or both terminals of the chamber. the other DC
An output terminal is connected to a conductive surface surrounding the arc tube to create an electric field between the conductive surface and the chamber to confine ions of the polarity of the surface within the chamber.

Preferably, the electrically conductive surface includes a reflector located generally near the lamp, and the luminaire housing has a transparent window surface near the lamp but opposite the reflector, and the luminaire housing has a transparent window surface near the lamp but opposite the reflector. A second conductive surface consisting of a thin transparent film deposited over the window creates a bias electric field surrounding the lamp. Although other conductive parts of the luminaire housing can also be used as bias-forming conductive surfaces, reflectors placed near the lamp have the greatest effect. Some lighting fixtures have a first reflector located in front of the lamp and a second reflector located behind the lamp. Each of these reflectors can have a curved surface.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to FIGS. 1 to 6.

FIG. 1 is a simplified diagram showing the connection of the main components of the device according to the invention. In the following, the invention will be described with respect to a luminaire containing high pressure sodium or metal halide. However, it must be emphasized that the invention can be used for different types of lighting fixtures and also for luminescent lamps using gases other than sodium.

The luminaire of FIG. 1 has a housing 10,
The housing has a transparent body 12, which can be a refractor or an openable door with a glass panel. The light source itself includes a plasma conductor 14 formed in a chamber such as an arc tube 16;
This tube contains an ionizable gas and is surrounded by an outer jacket or sheath 17. However, this lamp does not have to have an outer jacket, as is the case with many double-ended lamps. The shape and size of these elements vary depending on lamp type and manufacturer. The reflector 18 is shown as being on the opposite side of the light source from the door or refractor 12 and is designed to direct and surround light from a portion of the light source in a special light pattern. can be curved into

AC supply circuit 20 includes terminals 22 connectable to a standard AC voltage source. AC supply feed circuit 20 provides AC output to conductors 24, 25 connected to terminals at opposite ends of lamp 14. The DC circuit means 28 is
It is supplied with power from the C supply circuit 20 and outputs a DC voltage to positive and negative output terminals 30 and 31, respectively. chamber 16
In the illustrated embodiment with a sodium vapor plasma conductor 14 in the plasma conductor, the positive terminal of the DC circuit means 28 is connected to the reflector 18 and the negative terminal 31 is connected to the arc tube 16 at one end of the plasma conductor.

In operation of the simple circuit shown in FIG.
AC supply circuit 20 delivers AC current through conductors 24 , 25 from both ends of arc tube 16 to the plasma conductor to maintain the plasma in a condition that produces light passing through door or refractor 12 . The light is also directed or focused by reflector 18 . At the same time, a DC voltage is applied to the reflector and plasma conductor to make the reflector positive to the plasma. Since the plasma contains sodium ions with a positive charge, and a more positive potential than the plasma conductor is placed on the reflector 18, an electric field is created between the reflector and the plasma ions, and this electric field directs the positively charged plasma particles to the reflector. confine these plasma particles within the chamber 16. This electric field reduces the migration of these positive ions through the walls of the arc tube 16, extending the life of the arc tube and maintaining the sodium design balance, thus changing the color and output of the light. Improve over time.

Operation of the apparatus of FIG. 1 is improved by applying a conductive coating 34 to the surface of the door or refractor 12 and connecting the positive terminal 30 to the coating 34. As a result, the plasma can be surrounded by a repulsive electric field from all sides of the light source, confining the plasma ions within the plasma and further improving the operation and extending the lifetime of the device.

Further, as shown in FIG. 1, the DC opening means 28
The positive terminal of is connected 35 to the housing 10. The housing may be made partially or entirely of metal, and if not made partially electrically conductive by an electrically conductive film or filler. By connecting the positive terminal to this conductive portion, the entire housing 10 can create an electric field that confines ions within the chamber 16.

Of particular importance is the provision of one or more surfaces that substantially surround and enclose the lamp, creating a potential on these surfaces that repels ions and confines them within the arc tube chamber. This is done without the need for additional devices inside the lamp itself. Such internal devices are costly and undesirable. If redundant devices were incorporated into the outer jacket of the lamp, these devices would naturally be discarded along with the lamp at the end of its life, but the circuitry provided in the luminaire of the present invention allows the internal Can extend the life of the lamp.

FIG. 2 shows the relative positions of the light source 38, the reflector 39, the refractor 40, and the housing 41.
In this case, the reflector 39 is made of metal or has a metal surface, the refractor 40 also has a metal surface, and these refractors and the refractor and the electrically conductive housing 41 are
It is connected to the positive terminal of circuit means 28, while its negative terminal is connected to a plasma conductor light source. Again, assuming a sodium vapor lamp is used, a three-dimensional electric field 42 is formed between the plasma conductor and the surrounding shell-like body, which is extremely effective in confining the plasma particles within the chamber. It is valid. Since the shell-like body substantially surrounds the light source, its confinement effect is large. Structures such as the one illustrated in FIG. 2 are commonly used for optical reasons, but not for field effect reasons or to confine plasma ions within the plasma stream.

An example of applying this principle to one type of luminaire is shown in FIG. In this embodiment, the components of the luminaire are housed within the housing 44. The housing 44 is made of metal or filled with metal particles,
Alternatively, a metallized surface can be applied. The opening in the housing receives a glass or plastic refractor 46 which has a conductive coating 48 applied to its inside surface. The coating 48 is, for example, tin oxide or indium oxide, and leaves the refractor substantially transparent, but makes its interior surfaces electrically conductive. Such layers can be deposited on glass by conventional vapor deposition techniques.

A plasma chamber 16 surrounded by an outer jacket 17 is arranged behind the refractor 46, and a reflector 18 is arranged behind this light source.

The AC supply circuit 20 consists of a conventional metal halide lamp ballast tube 50, which is typically an autotransformer with a tap or common point arranged to connect to the AC power source. Or it is a peak load automatic regulator. Instead of the usual single ballast resistor capacitor connected in series between this ballast resistor transformer and the plasma chamber, two ballast resistor capacitors are connected in series with the two AC conductors leading from the ballast resistor transformer to the light source. Stabilizing resistance capacitors 52 and 53 are used. To ensure that the operating wattage of the lamp is accurate, each capacitor 52, 53 is selected to have a value twice the capacitance of a single series capacitor used in a conventional ballast resistance transformer. These capacitors provide isolation for the light source so as to apply a DC bias to the light source.

The voltage dividing means includes a potentiometer 54 connected across the output of the transformer, the potentiometer having contacts 55 connected to the DC circuit means 28. The contact 55 is connected to a parallel circuit of a capacitor 60 and a resistor 61 via a series resistor 56 and a diode 58. The opposite side of this parallel connection circuit is connected to a common line, which is connected to the conductive housing 44 by a screw terminal 62.

The positive output terminal of the DC circuit as this common line is connected to the reflector 18 and the conductive coating 4 on the refractor 46.
8. The negative side is connected to a movable contact 59 of a potentiometer 57. Both ends of the potentiometer are respectively connected to terminals of the plasma conductor chamber. The electric field thus obtained confines the positive ions within the chamber 16 and prevents their migration through the walls of the chamber. Since the positive terminal is connected to the housing at terminal 62, the housing itself of conductive material contributes to the formation of the confining electric field.

As previously mentioned, the apparatus illustrated in FIG.
Because of the electric field created by the proximity of reflector 18 and housing, it can be used without coating 48. In order to more completely surround the chamber and improve the confinement field effect, a reflector 18 is provided as shown in FIG.
can be constructed as a shell-like structure.

Furthermore, if the diode 58 is reversed, D
Since the C electric field can be reversed, essentially equivalent circuits can be used to confine positive or negative ions, the choice depending on the type of lamp and the ions or compounds used within it. Be careful what you do.

A circuit using an electromagnetic regulator is shown in FIG. The structure including the housing, reflector and light source is similar to FIG. 3 and the same numbers are used. AC supply circuit 64
is an electromagnetic regulator having a core 66 with three windings, all windings being insulated from the core and from each other. The isolated primary winding 68 is connected to a conventional AC power source. Output winding 70 is connected at its end to chamber 14 and tapped to be connected to starting circuit 72 . Starting circuit 72 may be any starting circuit known in the industry and generates a voltage pulse across the top of winding 70 that is amplified by a self-transforming effect in winding 70 to connect conductors 74 and 7.
5, which produces a relatively high voltage pulse that is applied to the deionized lamp to produce ignition. A suitable starting circuit is illustrated in FIG. 2 of U.S. Pat. No. 4,763,044 and elsewhere. Magnetic shunts 65, 67 are located across windings 68 and 70.

Floating ballast capacitor winding 76 includes a shunt capacitor 78 which performs the ballast capacitor function. This ballast winding 76 does not interfere with the insulation of the primary winding and also maintains the original A of the ballast tube system.
Does not interfere with C operation. Winding 76 is connected via a diode 80 to a capacitor 82 across which appears a DC bias voltage that is connected to the lighting system elements. Bleeder resistor 83 in parallel with capacitor 82
is connected. In this embodiment used for sodium vapor lamps, the negative terminal of this DC power supply is connected to common line 75 and plasma conductor chamber 16. The positive terminal is connected to reflector 18, conductor coating 48, and conductor housing 44. The function is similar to that of the other embodiments described above, with an electric field created between the reflector and the plasma conductor chamber to confine the gas and ions within the chamber.

Such biasing techniques allow changes in lamp design, such as increasing the loading (watts per square centimeter) of the quartz and polycrystalline alumina arc tube walls, increasing the lumens per watt (L.P. .M) Provides increased power output and improved color and other properties without increasing the rate of sodium loss from the plasma and arc tube.

FIG. 5 shows a further embodiment of the plasma-coupled circuit according to the invention, which is particularly simple and therefore economical and efficient. Similar to the embodiment of FIG. 3, an automatic transformer 92 is connected to the AC power source;
AC current is supplied to lamp 94 via series capacitors 96 and 97. A lamp starting circuit 98 is connected between the lamp sides of capacitors 96 and 97. A reflector 99 is arranged to reflect the light generated in the lamp 94.

DC circuit 100 includes a series circuit of a diode 102 and a resistor 104, and a radio frequency choke 106 for blocking high frequency, high voltage pulses from the lamp starting circuit. The diode is polarized such that the inductive ballast side of capacitor 97 is positive with respect to the lamp side of this capacitor, and capacitor 96 is polarized such that the inductive ballast side of this capacitor is positive with respect to the lamp side. Extreme. Capacitor 96 is dielectrically isolated from the housing. Finally, a conductor 108 connects the neutral or ground side of inductor 92 to reflector 99 and lamp housing 90.

When using this circuit, the neutral side of the inductive ballast resistor is positive with respect to the lamp side circuit of the lamp and capacitors 96,97. The plasma conductor itself is therefore negative with respect to the reflector and housing, creating an ion transfer inhibiting electric field, which improves lamp operation and life. Isolating capacitor 96 from the housing by a dielectric isolation element prevents capacitive shorting of high frequency, high voltage lamp ignition pulses from lamp starting circuit 98. The ballast resistor secondary serves as an inductance to suppress the starting pulse from the starting circuit. A charging circuit including diode 102, resistor 104 and choke 106 charges ballast capacitor 96 to the polarity shown. When the lamp is lit and draws a high AC lamp current, a portion of the charge on capacitor 96 is directed into ballast resistor capacitor 97 so that its DC voltage is equal or reversed, resulting in a net DC voltage along the lamp current loop. reaches zero. However, the lamp plasma circuit is negatively biased relative to the neutral or metal portion.

The AC voltage swings across the operating ramp of this circuit can have peak amplitudes close to or nearly equal to the DC bias voltage. Therefore, there is very little voltage time during a half cycle during which a reverse bias is present to eject sodium ions from the walls of the arc tube.

The DC voltage is automatically regulated by the circuit's lamp voltage clamp mechanism. Such a charging circuit 10
Two zeros could be used, but this is unnecessary since AC power operation transfers the required charge from one capacitor to the other.

To limit the current in the charging circuit, a resistor 104 is used, typically having a value of 10K ohms, 1 watt. As mentioned earlier, the RF choke blocks high voltages from the starting circuit, allowing high frequencies and high voltages to start and ignite the lamp, and also prevents high voltages from damaging other charging circuit elements. This can be prevented. Of course, the diode allows half-wave DC charging.

If it is necessary to discharge the ballast resistor capacitor and starting capacitor when the ballast resistor dies, high resistance bleeder resistors can be connected before and after these capacitors. If rapid discharge is required, by connecting a small relay consisting of a series of normally closed contacts connected to a small resistor before and after each capacitor, and by connecting the relay coil along a wire or ballast resistor secondary wire. Rapid discharge can be performed.

FIG. 6 shows a reflector structure suitable for use in the present invention. The lamp 110 is the primary reflector 1
11 and a secondary reflector 112. By using these two reflectors, the light from the lamp can be emitted in a specific pattern through the refractor or cover 113. Similar to the previous structure, these elements are mounted on housing 114.

By connecting one side of the DC power supply to both reflectors and the other side to one or both terminals of the lamp, these reflectors substantially surround the lamp and are not connected to other parts of the housing. Since it is closer to the lamp than the lamp, it creates a very efficient surrounding electric field. Any of the circuit structures described above can be applied to this reflector structure.

In the foregoing, the invention has been described with respect to a single luminaire. However, it is quite possible to apply the present invention to all lighting fixtures of the same type in an entire building. This is of course economical. The implementation technique is illustrated in FIG. Building 120 is equipped with a number of lighting fixtures, two of which are shown at 122 and 123. Each lighting fixture has a ballast resistor transformer 1
25 and a stabilizing resistance capacitor 126, these elements can be arranged similarly to FIGS. 3 and 4, but
It's not necessarily necessary. Each luminaire has a lamp 127, such as a sodium vapor lamp, and a reflector 128. It is also possible to arrange the starting circuit within or together with the ballast resistor circuit.

[0038] For ordinary AC power lines that supply power to buildings,
An AC current primary winding 129 and a DC isolation transformer 130 are connected. Lighting devices 122 and 123 are connected in parallel between the non-grounded side terminal and the grounded side terminal of the transformer secondary winding. Thus, in the illustrated embodiment of the luminaire, the primary portion of each luminaire is connected to an AC power source.

A DC power supply unit 132 is connected between the AC ungrounded wire coming out of the secondary side of the transformer 130 and the building ground, that is, the green wire in the three-wire power distribution system, and the positive terminal of this DC power supply is Connected to ground. This creates a DC bias between the ground wire and the ground, and the ground becomes positive with respect to the ground wire. To provide the desired bias to confine ions within the lamp according to the present invention, the reflector and/or housing of each luminaire (depending on the particular reflector or housing structure) may be connected to ground. Since the plasma conductor is connected to the ground AC wire, it is automatically biased negatively with respect to ground. The reflector and/or housing is therefore made positive to the plasma, creating the desired confinement electric field. In this way, all of the luminaire's wires need to be connected to the isolation transformer 130, even though other AC supply wires are used for other purposes within the building. Such an electric wire exclusively for DC bias is preferable.

[0040] The present invention is not limited to the above description, but can be modified and implemented as desired within the scope of the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a luminaire illustrating the principles of the invention including a plasma conductor chamber.

FIG. 2 is a schematic diagram illustrating a bias electric field created in an exemplary luminaire structure according to the present invention.

FIG. 3 is a schematic circuit diagram of a first embodiment of a luminaire including a system according to the invention;

FIG. 4 is a schematic circuit diagram of a second embodiment of a luminaire including a system according to the invention;

FIG. 5 is a schematic circuit diagram of a third embodiment of a luminaire including a system according to the invention;

FIG. 6 shows a first reflector and a second reflector of a lighting fixture according to the present invention.
FIG. 3 is a partial side cross-sectional view of a portion of the reflector.

FIG. 7 is a wiring diagram using the present invention for multiple lighting fixtures in a building.

[Explanation of symbols]

10 Housing 12 Refractor 14 Plasma conductor 16 Arc tube 18 Reflector 20 AC supply circuit 28 DC circuit means 50 Stable resistance circuit 64 AC power supply 66 core 68 Winding wire 70 Winding wire 72 Starting circuit 76 Stable resistance winding 92 Automatic transformer 98 Lamp starting circuit 122 Lighting equipment 123 Lighting equipment

Claims (19)

[Claims] 1. An electrical system for preventing ion loss from a plasma conductor in a high-intensity luminescent lamp, comprising an ionizable fill gas and a plasma material, such as a metal halide, which helps form a plasma conductor when evaporated during light emission. an arc tube chamber containing a first terminal and a second terminal; and first circuit means including a ballast resistive element connected to the first terminal and the second terminal for providing an AC operating voltage to the chamber. a conductive surface substantially surrounding and surrounding said chamber; second circuit means connected to a voltage source for generating a DC potential and having a negative terminal and a positive terminal; and one of said output terminals connected to a terminal of said chamber. and third circuit means for connecting and connecting the other output terminal to the conductive surface to create an electric field between the surface and the chamber to confine ions of the polarity of the surface within the chamber. A bias system for reducing ion losses in a lamp, characterized in that: 2. The conductive surface includes a conductive reflector disposed on one side of the chamber to direct light generated in the chamber in a desired direction.
Bias system described in. 3. The first circuit means is an AC circuit having a first conductor and a second conductor for providing an AC operating voltage across the terminals of the chamber and acting as an inductive ballast resistor during operation.
an inductive circuit means connected to a power supply, first and second ballast resistance capacitors connected in series to the first and second conductive wires, and voltage dividing means connected to the inductive circuit means, the voltage dividing means being connected to the inductive circuit means; 3. A biasing system as claimed in claim 2, including voltage dividing means connected to said second circuit means for generating a DC potential difference. 4. A second electrically conductive surface disposed opposite from the first electrically conductive surface with respect to the chamber, and wherein the third circuit is connected to the other electrically conductive surface. 2. The biasing system of claim 1, wherein the output terminal of the biasing system is connected to the second conductive surface. 5. The first conductive surface includes at least one partially transparent housing, and the first conductive surface is a conductive surface disposed on one side of the chamber to direct light generated within the chamber in a desired direction. a reflector, the second electrically conductive surface comprising an electrically conductive substantially transparent coating supported on an at least partially transparent housing surface on an opposite side of the chamber from the reflector. Biasing system according to claim 1. 6. The at least partially transparent housing includes a conductive outer housing for a lamp element and circuitry, the outer housing includes a transparent portion, and the third circuit means connects the negative output terminal to the outer housing. Biasing system according to claim 5, characterized in that it is connected to the housing. 7. The biasing system of claim 5, wherein the at least partially transparent housing supporting the conductive coating includes a light transmissive wall portion of the outer housing. 8. The biasing system of claim 1, wherein the conductive surface is curved to at least partially enclose the chamber. 9. The first circuit means includes an inductive circuit means connectable to act as an inductive ballast resistor during operation, the inductive circuit means including a first winding connectable to an AC power source. and a magnetically permeable core with A at both ends of said chamber.
a second winding for applying the DC operating voltage, and a third winding, a stabilizing resistance capacitor being connected between both terminals of the third winding, and the third winding for generating the DC potential. is connected to the second circuit means.
Bias system described in. 10. The biasing system of claim 9, wherein the conductive surface includes a conductive reflector located on one side of the chamber to direct light generated in the chamber. 11. A second electrically conductive surface disposed opposite from the first electrically conductive surface with respect to the chamber;
11. The biasing system of claim 10, wherein a circuit connects the second conductive surface to the other output terminal that is connected to the first conductive surface. 12. The first conductive surface includes at least one partially transparent housing, and the first conductive surface is a conductive surface disposed on one side of the chamber to direct light generated within the chamber in a desired direction. a reflector, the second electrically conductive surface comprising an electrically conductive substantially transparent coating supported on an at least partially transparent housing surface on an opposite side of the chamber from the reflector. Biasing system according to claim 9. 13. The at least partially transparent housing includes a conductive outer housing for a lamp element and circuitry, the outer housing includes a transparent portion, and the third circuit means connects the negative output terminal to the outer housing. 13. The biasing system of claim 12, wherein the biasing system is connected to a housing. 14. The biasing system of claim 12, wherein the at least partially transparent housing supporting the conductive coating includes a light transmissive wall portion of the outer housing. 15. The biasing system of claim 1, wherein said voltage source includes said first circuit means. 16. The first circuit means includes an A circuit having a first conductor and a second conductor for providing an AC operating voltage across the chamber terminals and acting as an inductive ballast resistor during operation.
C power supply, and first and second ballast resistor capacitors connected in series to the first and second conductors, and the second circuit means is connected to the first ballast resistor. the third circuit means includes a diode and a resistor connected in series between the chamber side of the capacitor and the inductive ballast resistor side of the second ballast resistor capacitor;
2. The biasing system of claim 1, including a conductive wire connected between an inductive ballast side of the second ballast capacitor and the conductive surface. 17. An at least partially conductive luminaire housing containing the lamp and the first, second and third circuit means, and means for insulating at least the first ballast capacitor from the luminaire housing. 17. The electrical system of claim 16, comprising: 18. The biasing system of claim 17, wherein said third circuit means connects said inductive side of said second capacitor to a conductive portion of said luminaire housing. 19. A chamber containing an ionizable filler gas useful for forming a plasma conductor and having first and second terminals and connected to the first and second terminals for providing an AC operating voltage to the chamber. in a method for preventing ion loss from a plasma conductor in a high-intensity light emitting lamp of the type comprising first circuit means comprising a ballast resistive element and a conductive surface proximate a chamber;
generating an electric potential and connecting one DC output having opposite polarity to the ions of the plasma conductor to one of the first and second terminals of the chamber and the other DC output to the conductive surface; forming an electric field between the conductive surface and the chamber to confine ions having the polarity of the conductive surface within the chamber.