WO2015101953A1

WO2015101953A1 - Switchless quartz metal halide lamp for probe-start and pulse-start lighting systems

Info

Publication number: WO2015101953A1
Application number: PCT/IB2015/050048
Authority: WO
Inventors: Junming Tu; Randy Robinson; Gregory Allen Golding
Original assignee: Koninklijke Philips N.V.
Priority date: 2014-01-06
Filing date: 2015-01-04
Publication date: 2015-07-09

Abstract

A metal halide (MH) lamp includes an arc tube having end sections and a center portion defining a discharge cavity; an electrode assembly having electrode leads arranged in a symmetric electrode configuration; and a fill contained within the discharge cavity and including a noble gas mixture, mercury, and a salt mix of a metal halide for allowing a starting operation of the MH lamp using a starting voltage of less than 500 volts. The noble gas mixture includes neon from 99.9% to 99.0% and argon from 0.1% to 1.0%. The lamp may also have an outer envelope around the arc tube, where the outer envelope includes neon gas having the same partial pressure as the partial pressure of the neon of the gas mixture.

Description

SWnCHLESS QUARTZ METAL HALIDE LAMP FOR PROBE-START

AND PULSE-START LIGHTING SYSTEMS The present system relates to a quartz metal halide (QMH) lamp and, more particularly, to a QMH lamp suitable for operation using both probe-start and pulse-start lighting systems.

To reduce energy use and costs due to lighting, it has become commonplace to retrofit existing lamps with energy-efficient lamps such as quartz metal halide (QMH) lamps. QMH lamps provide white light and are frequently used as a retrofit lamp in many lighting applications such as outdoor spaces, parking lots, retail stores, and industry lighting. Over 80% of conventional lighting systems for the above-mentioned lighting applications are configured for probe-start (e.g., switch start) lamps as opposed to being configured for pulse-start lamps.

Conventional probe start QMH lamps have a bi-metal switch and a starting electrode which provide for reliable ignition for operation with ballasts that are used in probe-start type lighting systems. This added circuitry increases manufacturing complexity, time, and cost and can reduce reliability. Further, most, if not all, commercial QMH lamps in the North American market are probe-start QMH lamps and, therefore, use a starting electrode.

However, conventional probe-start QMH lamps are not compatible for operation with pulse-start lighting systems and conventional pulse-start QMH lamps are incompatible with conventional probe-start lighting systems. For example, conventional pulse-start lamps must operate on a pulse-start ballasts which output high ignition voltage pulses, that are typically between 3000V and 4000V for starting. In contrast, conventional probe-start ballasts do not have high voltage igniters and, thus do not output the aforementioned voltage pulses.

Accordingly, conventional pulse-start lamps cannot be ignited on probe-start systems. Further, conventional probe-start lamps rely upon starting electrodes and bi-metal switches to start on probe-start ballasts which do not output high voltage pulses. For example, if a conventional probe start QHM lamp configured for a probe-start lighting system, is coupled to a pulse-start lighting system, the starting mechanism (e.g., including the starter electrode and the bi-metal switch) and could fail due to arcing between two opposite potentials of the bi-metal switch.

Further, as probe-start QMH-type lamps are generally incompatible with pulse-start ballasts, and vice versa, probe-start QMH lamps lamp cannot be used as energy-efficient drop-in replacement lamps in pulse-start lighting systems, and pulse-start lamps QMH lamps cannot be uses as an energy-efficient drop-in replacement for probe-start lighting systems.

The system(s), device(s), method(s), user interface(s), computer program(s), processes, etc. (hereinafter each of which will be referred to as system, unless the context indicates otherwise), described herein address problems in prior art systems.

In accordance with embodiments of the present system, there is disclosed a metal halide (MH) lamp comprising an arc tube, such as a quartz arc tube, having end sections and a center portion situated between the end sections, the center portion (CP) defining at least part of a discharge cavity situated between opposed end walls (IL) and having an inside diameter (ID) which is substantially constant along a substantial portion of a longitudinal length of the discharge cavity, and the opposed end portions being substantially flattened in cross section, each end section having only a single opening. The discharge cavity may have an aspect ratio (AR) defined by a length of the discharge cavity between the opposed end walls (TL) to the ID, wherein the AR is between 2:1 and 4: 1.

The MH lamp further comprises an electrode assembly having electrode leads arranged in a symmetric electrode configuration, such as comprising an even number of electrode leads; and a fill contained within the discharge cavity and comprising a noble gas mixture, mercury, and a salt mix, the salt mix comprising a metal halide for allowing a starting operation of the MH lamp using a starting voltage of less than 500 volts, such as an open circuit starting voltage of less than 500 volts provided by a probe-start ballast. The noble gas mixture may comprise neon from 99.9% to 99.0% and argon from 0.1% to 1.0%, and the lamp may have an outer envelope around the arc tube, where the outer envelope contains neon gas having a same partial pressure as a partial pressure of the neon of the gas mixture.

Each of the electrode leads may be symmetric about a center point of the center point (CP) and longitudinal axis of the quartz arc tube, and may be opposed to each other and symmetrically located about a center of the discharge cavity. Further, each lead electrode of the electrode assembly may have first and second ends and an electrode coil situated at the second end such that a backspace distance between each electrode coil and an adjacent end wall of the opposed end walls is the same. Each lead electrode may further extend past an outer periphery of the arc tube, where the backspace distance of each of the opposed lead electrodes is equal to or greater than 2 mm.

The electrode assembly may consist only of a pair of opposed lead electrodes, and the MH lamp may be configured to be started using the pair of opposed lead electrodes when coupled to a probe-start ballast for providing the open circuit starting voltage of less than 500 volts to start the MH lamp. The MH lamp may be further started using voltage pulses having an amplitude between 3000 and 4000 volts provided by a pulse-start ballast.

The invention is explained in further detail, and by way of example, with reference to the accompanying drawings wherein:

FIG. 1 is front partial cutaway view of an arc tube in accordance with embodiments of the present system;

FIG. 2A is top partial cutaway view of an arc tube in accordance with embodiments of the present system;

FIG. 2B is an end view of a portion of the arc tube in accordance with embodiments of the present system;

FIG. 2C is cross sectional view of a portion of the arc tube taken along lines 2C-2C of FIG. 1 in accordance with embodiments of the present system;

FIG. 3 is a side view of a lamp including an arc tube in accordance with embodiments of the present system; and

FIG. 4 is a side view of a lamp after 100 hours of operation in accordance with embodiments of the present system. The following are descriptions of illustrative embodiments that when taken in

conjunction with the following drawings will demonstrate the above noted features and advantages, as well as further ones. In the following description, for purposes of explanation rather than limitation, illustrative details are set forth such as architecture, interfaces, techniques, element attributes, etc. However, it will be apparent to those of ordinary skill in the art that other embodiments that depart from these details would still be understood to be within the scope of the appended claims. Moreover, for the purpose of clarity, detailed descriptions of well known devices, circuits, tools, techniques and methods are omitted so as not to obscure the description of the present system. It should be expressly understood that the drawings are included for illustrative purposes and do not represent the entire scope of the present system. In the accompanying drawings, like reference numbers in different drawings may designate similar elements.

FIG. 1 is front partial cutaway view of an arc tube 100 in accordance with embodiments of the present system. The arc tube 100 may include glass tube 102 (e.g., a discharge vessel), first and second lead assemblies (e.g., electrode lead assemblies, electrodes, or leads 116) 116-1 and 116-2, respectively, and a fill F. The glass arc tube 102 may have opposed ends 128 and substantially cylindrical center portion 108 defining a cavity 112 (e.g., a discharge space) suitable for containing the fill F (e.g., a discharge tube (DT) fill) under pressure. The center portion 108 may be situated between the opposed end walls 110 and may be substantially cylindrical with an inside diameter (ID) and a length (Dcp). The center portion 108 may further have an outside wall thickness of between about 1.0mm to 2.0mm depending on wattage and operation orientations. However, other outside wall thickness values and/or ranges of values are also envisioned. The inside diameter (ID) of center portion 108 may be between 13mm to 25mm for medium to high power quartz metal halide lamps. However, other values and/or ranges of the ID are also envisioned. Further, in accordance with some embodiments, the length (Dcp) of the center portion 108 should be greater than about 22mm for medium-wattage lamps (e.g., lamps rated at less than 400 watts or having a power range of 5 to 400 Watts), and 60mm for high- wattage lamps (e.g., lamps rated at more than 400 Watts or having a power range of 425 to lOOOWatts or more). However, other wattages and lengths of Dcp are also envisioned. However, in yet other embodiments other values and/or ranges of values are also envisioned. In some embodiments, a center portion aspect ratio (Cpar) may be defined as a ratio of the length (Dcp) to the inside diameter (ID) of the center portion 108 and may be between 2 and 4. However other values and/or ranges of values for Cpar are also envisioned. It is further envisioned that the discharge cavity 1 12 may have an aspect ratio (AR) defined by the length (dIL) (e.g., of the discharge cavity between the opposed end walls 1 10) to the inside diameter (ID), and which is between 2 and 4. However, other values and/or ranges of values for the AR are also envisioned. This may avoid an oval-shaped center portion (when viewed from the top or side) configuration which may be formed when using a narrow cavity (e.g., a cavity with a small inside diameter). An advantage of providing an oval-shaped arc tube includes less energy loss in the cavity which can yield a high vapor pressure and higher lumens output.

The glass tubing or tube 102 may be formed from a suitable material such as a quartz material or the like. The center portion 108 may be located between flattened sections 132 (which may also be referred to as end sections) of the glass tube 102 such that the each flattened section 132 is located adjacent to a corresponding opposed end 128 of the glass tube 102. The flattened sections 132 may be flattened using any suitable method such as by heating and pressing portions of the glass tube 102.

The first and second lead assemblies 116-1 and 116-2 (generally 116-x), respectively, may be substantially similar to each other. Accordingly, only a single lead assembly 116-x will be discussed for the sake of clarity, unless the context indicates otherwise. Each lead assembly 116- x may include first and second ends 124 and 104, respectively, and may extend through a corresponding opening 114 of the glass tube 102 such that the second end 104 and an electrode coil 130 attached thereto are situated within the cavity 112 of the glass tube 102. Each of the lead assemblies 116-x may include a first portion 122 located at the first end 124, a second portion 118 located at the second end 104, and a third portion 120 located between the first and second portions 122 and 1 18, respectively. The electrode coil 130 may be located at, or adjacent to, the second end 104 thereof.

The first through third portions 122, 1 18, and 120, respectively, of the lead assemblies 116- x may be coupled to each other using any suitable method such as welding, frictional fitting, etc. The lead assemblies 116-x may include a sealing section formed from any suitable foil material such as a molybdenum foil located at the third portion 120. The ends 104 of the lead assemblies 116-x may be separated from each other by a distance Die. The first ends 124 of the first and second lead assemblies 116-1 and 116-2, respectively, extend beyond an outer envelope of the glass tube 102. Each of the electrode coils 130 may be formed from a suitable material such as a tungsten coil and may have opposed first and second ends, wherein the first ends are situated furthest into the cavity 112 and the second ends are situated closest to an adjacent one of the end walls 110 of the cavity 106 and separated from an adjacent end wall 110 by a backspacing distance (DBS) which should be greater than or equal to about 2.0 mm to reduce or entirely prevent possible electron traps due to impurities on the wall of the arc tube 100. However, in yet other embodiments, the DBS may have other values.

The cavity 112 may have an internal length dIL between the opposed end walls 110 of between 25mm and 120mm for medium and high power metal halide lamps, respectively.

However, other values and/or ranges of values of dIL are also envisioned. The openings 114 of the glass tube 102 should be sealed about the corresponding lead assemblies 116-x so as to seal the cavity 104 so that pressure with the cavity 112 will be maintained.

The glass tube 102 should be configured such that in some embodiments each of the lead assemblies 116-x may be substantially equally spaced from an adjacent interior wall 126 of the center portion 108 and/or the end walls 110 which define at least portions of the cavity 1 12 of the glass tube 102. In other words, the cavity and press area (in the arc tube ends) should not be very narrow. For example, in some embodiments the press area may be slightly larger than the cavity

112 (inside the glass tubing 102).

Thus, the arc tube 100 may be configured such that each lead assembly 116-x may be equidistant from corresponding adjacent interior walls (e.g., 126 and 110) of the cavity 112 so that the lead assemblies may be considered to be symmetrically located relative to at least the cavity 112 of the arc tube 100 (e.g., in one or more axes such as x, y, and/or z axes of the arc tube 100), as opposed to being asymmetrically located relative to at least the cavity of the arc tube 100. Further, assuming that a center point CP (e.g., which may include one or more center points such as CP_X CP_y, and CP_Z, each of which may be located about x, y, and/or z axes, respectively, of the glass tube 102) of the arc tube 100 is a center point of the cavity 112 and/or glass tube 102 (assuming a substantially symmetric glass tube 102), then, each of the lead electrode assemblies 116-x may symmetrically located about the CP(s) of at least one of a cavity 112 and/or glass tube 102 of the arc tube 100. In comparison, each lead assembly of a three-lead probe-start lamp is not equidistant from at least one center point of the cavity (e.g., in the x, y, and/or z axes) of the arc tube, adjacent interior walls of the glass tube 102, and/or the glass tube 102 itself. Thus, conventional three-lead probe-start lamps are not symmetric about any of their center points.

The fill (F) may include a starting gas mixture (inner gas), one or more salts, and mercury (Hg). In accordance with some embodiments, an Hg dose may range from about 25mg to 200mg for medium and high power QMH lamps. However, the Hg dose may be further dependent upon lamp voltage and/or arc length. For example, in some embodiments it is envisioned that a ratio of Hg/arc length may be between 8mg/mm and 24mg/mm arc tube length. With regard to the starting gas mixture, this mixture may include one or more gasses which may act as a penning mixture and may include at least one noble gas or mixture thereof such as neon- argon (Ne-Ar) gas mixture. For example, the Ne-Ar gas mixture may include about 99.5% neon and 0.5% argon so as to act as a penning mixture and may be configured to reduce the ignition voltage of the lamp 100. However, in yet other embodiments, the Ne-Ar gas mixture may range from 99.9%-0.1% Ne-Ar to 99.0%-1.0% Ne-Ar . Thus, in some embodiments, the Ne can range from 99.0% to 99.9% with the remainder being Ar in the gas mixture. Thus, the Ar can range from 0.1% to 1% based upon a percentage of Ne in the Ne-Ar gas mixture. The Ne-Ar gas may have a fill pressure of between 20 torr and 90 torr in some embodiments, and in other embodiments the Ne-Ar gas may have a fill pressure of between 20 torr and 50 torr to enhance ignition of the lamp, as the lamp ignition voltage may be substantially proportional to gas pressure. However, other ranges for the Ne-Ar fill pressure within the cavity 112 are also envisioned such as from 90 to 200 torr. However, when using higher Ne-Ar fill pressure, a ballast which can provide a sufficiently high voltage to start the lamp may be desirable. Further with regard to lamp ignition voltage, generally this is proportional to arc length and gas pressure. Thus, for a given arc length, the lower the fill pressure, the easier it is to start the lamp.

Conversely, for the same given arc length, the higher the fill pressure, the harder it is to start the lamp. Thus, a lamp with a higher fill pressure may require a higher ignition voltage be provided by its ballast to properly start the lamp. Conversely, for the same given arc length, a lamp with a lower fill pressure (e.g., than the amp with the higher fill pressure) may require a lower ignition voltage be provided by its ballast to properly start the lamp.

The one or more salts may include a metal halide such as sodium iodide (Nal) and scandium iodide (SCI3) and ThLj. The molar ratio (MR) of the Nal to the Sc¾ may be between about 19: 1 For example, in some embodiments, the MR may range from between 11 and 38 for a quartz metal halide lamp. However, other values are also envisioned. The molar ratio may be calculated, for example, based on a ratio of Nal mole (weight divided by molecular weight) and ScB .

The Ne-Ar gas mixture of the probe-start quartz metal halide lamps in accordance with embodiments of the present system reduces the ignition voltage significantly compared with conventional three-lead probe-start lamps quartz-metal halide lamps which use 100% Ar fill gas. Accordingly, lamps configured in accordance with embodiments of the present system may start using open circuit voltage (OCV) as provided by a probe start ballast (e.g., typically below 500V) and does not require voltage pulses (e.g., as provided by pulse start ballasts) for starting. Thus, lamps configured in accordance with embodiments of the present system may be configured to start using an OCV which may be below 500V as provided by a probe-start ballast (e.g. without high-voltage pulses) and may be configured to start and operate on a pulse start lighting system (e.g., using power supplied by pulse start ballasts) without modification. Thus, lamps in accordance with embodiments of the present system may be referred to as hybrid probe-start and pulse-start lamps. Alternatively, or in addition, Thus, lamps in accordance with embodiments of the present system may be referred to as probe-start lamps that does not have bi-a metal switch and/or a starting electrode, and yet starts and operates with a starting voltage of less than 500V using (OCV as provided by a probe start ballast, without requiring high voltage pulses (such as 3000V to 4000V Volts pulses typically provided by pulse-start ballasts in lamps that do not have a bi-metal switch and a starting electrode.

In some embodiments, with regard to the backspacing, because QMH lamps in

accordance with some embodiments of the present system contain iodides including sodium iodide and scandium iodide, control of impurities such as moisture and hydrogen may be important. This is because iodide may form hydrogen iodide (HI), which is an electron-absorbing species, to form HI-. If not controlled, this electron-absorbing species may trap electrons and make lamp starting difficult or impossible. Furthermore, as hydrogen iodide may exhibit a tendency to experience voltage spikes during initial lamp warm-up and, if these voltage spikes reach a threshold level (e.g., >160V for medium voltage QMH lamps), a ballast providing power to a corresponding lamp may be not able to sustain the arc and the lamp may extinguish.

Furthermore, because of manufacturing issues, a surface of the arc tube (e.g., a quartz arc tube such as 101) of a lamp may be contaminated by impurities such as moisture and hydrocarbons (organic contaminants). Accordingly, the electrodes may be located at a certain minimum distance from an interior wall of the arc tube to avoid electrons from being taken away by these impurities. In accordance with some embodiments, a distance ratio of A to B (A/B) may be defined, where A is a distance along a longitudinal axis of the lamp 100 between a second end 104 of a corresponding electrode lead assembly 116-x and an adjacent end wall 1 10 where the corresponding electrode lead assembly 1 16-x enters the discharge cavity 112, and B is a distance between the second end 104 of the corresponding electrode lead assembly 116-x and a closest portion of the adjacent end wall 110 as shown in FIG 1 , and have a ratio of about 1. However, in yet other embodiments, the ratio of A to be B be have a range of about 0.9 and 1.1. Illustratively, A and B have approximately the same dimension and are at least 3 mm, each. However, A may be in a range of 3 mm to 7mm and B is in a range of 3 mm to 7mm for medium- wattage lamps (e.g., 50 to 400 Watts); for high-wattage lamps (e.g., 425 to lOOOWatts or more), A is in a range of 4mm to 9mm and B is in a range of 4mm to 9mm.

FIG. 2A is top partial cutaway view of an arc tube 100 in accordance with embodiments of the present system. The flattened sections 132 extend about the center portion 108 of the arc tube 102 and may be configured to support the arc tube 102. The flattened sections 132 may be crimped about respective lead assemblies 116-x so as to seal the cavity 112.

The lead assemblies 116-x are symmetrically located about the center point (CP) of the lamp. Further, in some embodiments the lamp and/or is substantially symmetric about the center point (CP) as opposed to be substantially asymmetric as is the case with conventional three-lead lamps such as conventional probe-start lamps.

FIG. 2B is an end view of a portion of the arc tube 100 in accordance with embodiments of the present system. Both flattened sections 132 are substantially flat in cross section and as are substantially similar to each other. Accordingly, only a single end view of the arc tube 100 is shown for the sake of clarity.

FIG. 2C is cross sectional view of a portion of the arc tube 100 taken along lines 2C-2C of FIG. 1 in accordance with embodiments of the present system. The cavity 112 includes the fill F which may include one or more of mercury and salts (e.g., a salt mix). The salt mix may include a metal halide such as one or more of sodium iodide (Nal), scandium iodide (Sc^), and ThLj and may have a specific mole ratio (MR) which may define a ratio of Nal to Scl₃ and will be described below. However, ThLj may be optional in some QMH lamps in accordance with embodiments of the present system. However, as Th acts as an emission material to provide initial electrons for ignition, it may be desirable to provide a Th in other areas of the lamp 100 such as in the electrodes. For example, it is envisioned that some QMH lamps the electrodes may include a small amount of Th0₂, such as about 2%. Thus, some embodiments may not include Thl₄ in the salt mix but may include Th in the electrodes as Th0₂, if desired. However, in yet other embodiments, Thl₄ may be provided in the salt mix to assure that if the Th0₂ in the electrodes is lower than expected, or Th is depleted during lamp life due to chemical reactions, a sufficient amount of Th may be available to provide an initial source of electrons for lamp ignition.

FIG. 3 is a side view of a bulb 300 including an arc tube 100 in accordance with embodiments of the present system. The lamp 300 may include one or more of an outer bulb or envelope 352, the arc tube 100, a frame including a first frame portion 358 and a second frame portion 360, and a base 356.

The outer bulb 352 may be formed from a suitable material such as glass and may define at least part of an outer cavity 354 suitable for maintaining a gas or gas mixture at a desired pressure. The arc tube 100 may be situated within the outer cavity 354. The outer cavity 354 may be filled with an outer gas or gas mixture such as Ne-N₂ at a pressure to prevent or reduce the diffusion of Ne from within the arc tube 100 to the outer cavity 354. Accordingly, the partial pressure of the Ne in the outer gas of the cavity 354 and the Ne (of the inner gas) in the cavity of the arc tube 100 may be substantially equal to each other. For example, in accordance with some embodiments, the outer cavity 354 may include a Ne-N₂ with a partial pressure of Ne (e.g., of the outer gas) which is equal to the partial pressure of the Ne gas (e.g., of the inner gas) within the cavity 112 of the lamp 100, 300. The outer bulb 352 should be configured to maintain the pressure within the outer cavity 354.

The outer bulb 352 may be coupled to the base 356 using any suitable method. The base 356 may be configured to be coupled to any suitable socket depending upon the application. For example, in some embodiments, the base 356 may include threads which may be configured to be coupled to a corresponding threaded receptacle of a probe and/or pulse start lighting system.

The outer bulb 352 may include a stem 368 having openings through which first and second stem leads 370 and 372, respectively, may pass. The first stem lead 370 may have first and second ends and may be coupled to the base 356 adjacent to its first end and coupled to the first frame portion 358 adjacent to its second end so as to electrically couple the first frame portion 358 to the base 356. The second stem lead 372 may be have first and second ends and may be coupled to a contact 374 adjacent to the first end and to the second frame portion 360 so as to electrically couple the second frame portion 360 to the base contact 374.

An insulator 376 formed from a suitable insulator such as Vitrite™ may insulate the contact 374 from the base 356. The frame may include a support portion 378 which be coupled to the outer bulb 352 and to the first frame portion 358 so as to at least partially support the first frame portion 358 and the arc tube 100.

One or more getters such as getter 362 may be located with the outer cavity 354 and coupled to portions of the frame such as the first frame portion 358, the support portion 378, and/or the second frame portion 360. The one or more getters may be configured to absorb desired contaminates such as oxygen, moisture, etc., within the outer cavity 354. One or more portions of the frame may be insulated by insulators, such as insulator 366 which may form a cylinder through which at least a portion of the frame may pass and so as to electrically and/or thermally insulate the corresponding portion of the frame (e.g., the first frame portion 358) and the arc tube 100 from each other. The insulator 366 may be formed from a suitable material such as a quartz glass.

Experimental Results:

FIG. 4 is a side view of a lamp 400 after 100 hours of operation in accordance with embodiments of the present system. The lamp 400 may be similar to the lamp 300 and may include an outer bulb 452 and an arc tube 401 (which may be similar to the arc tube 100).

However, support rings 492 at least partially couple the arc tube 401 to a first frame support 468. The lamp 400 was operated using a probe-start ballast during testing. The lamp 400 may be a protected 400-watt QMH lamp and may include quartz shroud 494 which surrounds sides of the arc tube 401 and should be configured to reduce the likelihood of portions of the arc tube 401 contacting the outer bulb 452 in case of a failure of the arc tube 401. Further, the lamp 400 does not include an optional coating.

Experimental results will now be described with reference the figures and Tables 1 -5. The experimental results were obtained using switchless QMH pressed-body lamps in accordance with embodiments of the present system, such as that shown in FIG. 4 and having at least some of specifications shown in Tables 1 -5 below.

During testing of lamps formed in accordance with embodiments of the present system, an ignition test for zero hour lamps was performed according to the ANSI requirements (e.g., ANSI C78.43-2005). During testing, a peak voltage was set at 495V. For 175W and 400W quartz metal halide lamps, ANSI specifies a requirement of lamp ignition within two minutes at a minimum peak voltage 495V. To meet this above-mentioned peak voltage, line voltage was set to about 190V (vs. nominal voltage of 240V). Test results indicate that QMH lamps of 175 W (unprotected) and 400W (protected) in accordance with embodiments of the present system, meet or exceed the ANSI requirements (e.g., ignition < 120 seconds).

Tables 1 and 2 below show ignition test results for the 175W and 400W lamps, respectively, formed in accordance with embodiments of the present system. The 175W and 400W lamps tested as shown in Tables 1 and 2 below include an inner cavity discharge tube (DT) fill of Ne-Ar, and an outer cavity fill of N₂-Ne. Further, the peak voltage was set to 495 volts.

Table 1

Table 2

400 Watt Lamp/E iU M59-type Ballast Input V =188 volts

Lamp number Ignition Time (sec) Hydrogen Spikes (V) Aging time (minutes)

1 1 <5 7

2 1 <10 7

3 1 14 7 Table 3 below illustrates lamp parameters for the 400 Watt lamps described with respect to Table 2.

Table 3

Table 4 below shows a comparison of light technical properties of switchless protected QMH 400W lamps formed in accordance with embodiments of the present system and similar properties for a conventional 400W QMH lamp with a bi-metal switch (shown in the last row see, MP400W/BU).

Table 4

As shown in Table 4, the light properties of the 400W QMH lamps formed in accordance with embodiments of the present system is similar to and better than properties of the

conventional 400W lamp, including providing more lumens, namely greater than 3800 lumens, such as providing from 38500 to 41500 lumens for 400W QMH lamps formed in accordance with embodiments of the present system. Further, low, medium and high wattage QMH lamps formed in accordance with embodiments have a long life of up to 20,000 hours, a high efficiency or Lumen Per Watt (LPW or lm/W), such as, from 80 to 125 lm/W where, for 400W QMH lamps formed in accordance with embodiments, the LPW is from 95 to 105. As used herein, x and y are color coordinates based on International Commission on Illumination (CIE) in

1931 CIE 1931 chromaticity diagram. CCT refers to correlated color temperature relative to completely radiating source (blackbody). CRI refers to color rendering index. MPCD refers to minimum perceptible color difference. The smaller the MPCD, the better for the color to close to the natural light source. QMH lamps formed in accordance with embodiments output white or natural light with small MPCD, such as less than 25, where x is from 0.33 to 0.47, y is from 0.35 to 0.43, CCT is from 2700K to 5000K , and MPCD is from -25 to 25 . QMH lamps formed in accordance with embodiments output white or natural light of at least 3800 lumens for a QMH 400W lamp formed in accordance with embodiments of the present system and may be used in any application requiring such white or natural light and high lumen output, such as outdoor spaces, parking lots, retail stores, stadiums and industry lighting, for example.

In accordance with yet other embodiments, there is provided a QMH lamp in accordance with embodiments of the present system including pressed bodies and the specifications as illustrated in Table 5 below each of which includes a pressed body.

Table 5

With regard to mounts, in accordance with embodiments of the present system, the 175, 400, and 1000 Watt lamp may include any suitable mount such as an ED17-, ED37-, BT56-type mounts. In some embodiments, wattage may be 400W in an ED37-type bulb/mount and 1000W in a BT56-type bulb/mount. However, in yet other embodiments, other types of bulbs and/or mounts may be used. Further, in yet other embodiments the ED17-type mount may be formed without a shroud. In accordance with embodiments of the present system, bulbs may include protected (e.g., with a quartz shroud) and/or non-protected (e.g. without a quartz-shroud) quartz metal halide lamps. Further, in accordance with some embodiments, an STlOl-type getter may be included. The outer Ne-N₂ gas may, for example, include 11.7% Ne gas to achieve an Ne partial pressure equilibrium between the inner gas of the arc tube and the outer gas, with the remainder including, for example, 88.3% N₂.

Further, in accordance with embodiments of the present system, a base of the lamp may include an extended eyelet. However, in yet other embodiments, other types of bases are also envisioned. For example, in some embodiments, the 400-Watt lamps may include a base such as an extended-eyelet-type mogul base and the 175-Watt lamps may include a medium mogul-type base.

Accordingly, lamps formed in accordance with embodiments of the present system may eliminate the need for a bi-metal switch and/or a starting electrode of probe-start QMH lamps. This may reduce manufacturing complexity and time and lower costs. Additionally,

environmental benefits may be obtained due to reduced power consumption and reduced material use. Further, lamps in accordance with embodiments of the present system may be used with both probe-start lighting systems, where lamps are started using starting voltage of less than 500 volts, as provided by open circuit voltage (OCV) of a probe start ballast probe-start ballasts, and pulse-start (PS) lighting systems where lamps are started using starting voltage pulses 3000 and 4000 volts, having a minimum pulse width of Ο μβ at 2700V and a minimum pulse repetition rate of 1 per half cycle as provided by pulse-start ballasts, for example, economies-of-scale may be obtained due to the use of a single lamp-type for both lighting systems, and/or incorrect lamp installation be prevented which may lead to reduce costs due to waste (e.g., due to burnt-out bulbs). Moreover, QMH lamps in accordance with embodiments of the present system may output white or natural light, and have a long life, a high lumen output and a high efficiency.

Further variations of the present system would readily occur to a person of ordinary skill in the art and are encompassed by the following claims.

Finally, the above-discussion is intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present system has been described with reference to exemplary embodiments, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the broader and intended spirit and scope of the present system as set forth in the claims that follow. In addition, the section headings included herein are intended to facilitate a review but are not intended to limit the scope of the present system. Accordingly, the specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

The section headings included herein are intended to facilitate a review but are not intended to limit the scope of the present system. Accordingly, the specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

In interpreting the appended claims, it should be understood that:

a) the word "comprising" does not exclude the presence of other elements or acts than those listed in a given claim;

b) the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements;

c) any reference signs in the claims do not limit their scope;

d) several "means" may be represented by the same item or hardware or software implemented structure or function; 2013PF01123 e) any of the disclosed elements may be comprised of hardware portions (e.g., including discrete and integrated electronic circuitry), software portions (e.g., computer programming), and any combination thereof;

f) hardware portions may be comprised of one or both of analog and digital portions; g) any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise;

h) no specific sequence of acts or steps is intended to be required unless specifically indicated; and

i) the term "plurality of an element includes two or more of the claimed element, and does not imply any particular range of number of elements; that is, a plurality of elements may be as few as two elements, and may include an immeasurable number of elements.

Claims

1. A metal halide (MH) lamp (100) comprising:

an arc tube (102) having end sections (128) and a center portion (108) situated between the end sections (128), the center portion (108) defining at least part of a discharge cavity (1 12) situated between opposed end walls (1 10);

an electrode assembly comprising an even number of electrode leads (116); and a fill contained within the discharge cavity (112) and comprising a noble gas mixture, mercury, and a salt mix, the salt mix comprising a metal halide for allowing a starting operation of the MH lamp (100) using a starting voltage of less than 500 volts.

2. The MH lamp (100) of claim 1 , wherein the fill further allows the starting operation using starting voltage pulses having an amplitude between 3000 to 4000 volts.

3. The MH lamp (100) of claim 1, wherein the noble gas mixture comprises neon from 99.9% to 99.0% and argon from 0.1 % to 1.0%.

4. The MH lamp (100) of claim 3, further comprising an outer envelope (352) around the arc tube (102), wherein the outer envelope (352) contains neon gas having a same partial pressure as a partial pressure of the neon of the gas mixture.

5. The MH lamp (100) of claim 1, wherein each of the electrode leads (1 16) is symmetric about a center point (CP) of the center portion (108).

6. The MH lamp (100) of claim 1, wherein the electrode assembly has a symmetric electrode configuration, wherein the discharge cavity (1 12) has an inside diameter (ID) which is substantially constant along a substantial portion of a longitudinal length of the discharge cavity (1 12), and wherein the end sections (128) are substantially flattened in cross section, each end section (128) having only a single opening.

7. The MH lamp (100) of claim 1, wherein each of the lead electrodes (116) is opposed to each other and symmetrically located about a center of the discharge cavity (1 12).

8. The MH lamp (100) of claim 1 , wherein each lead electrode (116) of the electrode assembly has first and second ends (124, 104) and an electrode coil (130) situated at the second end (104) such that a backspace distance (101) between each electrode coil (130) and an adjacent end wall of the opposed end walls is the same, wherein each lead electrode (1 16) further extends past an outer periphery of the arc tube (102); and wherein the backspace distance (101) of each of the opposed lead electrodes is equal to or greater than 2 mm.

9. The MH lamp (100) of claim 1, wherein the electrode assembly consists of a pair of opposed lead electrodes (1 16), and wherein the MH lamp is configured to be started using the pair of opposed lead electrodes (1 16) when coupled to a probe-start ballast.

10. The MH lamp (100) of claim 1, wherein the discharge cavity (1 12) has an aspect ratio (AR) defined by a length of the discharge cavity between the opposed end walls (110) to an inside diameter (ID) of the discharge cavity (1 12), and wherein the AR is between 2: 1 and 4: 1.

11. A metal halide (MH) lamp (100) comprising:

a quartz arc tube (102) having end sections (128) and a center portion (108) situated between the end sections (128), the center portion (CP) defining at least part of a discharge cavity (1 12) situated between opposed end walls (1 10) and having an inside diameter (ID) which is substantially constant along a substantial portion of a longitudinal length of the discharge cavity (1 12), the end sections (128) being substantially flattened in cross section, each end section (128) having only a single opening;

an electrode assembly having electrode leads (116) arranged in a symmetric electrode configuration; and

a fill contained within the discharge cavity (112) and comprising a noble gas mixture, mercury, and a salt mix, the salt mix comprising a metal halide for allowing a starting operation of the MH lamp (100) using an open circuit starting voltage of less than 500 volts provided by a probe-start ballast.

12. The MH lamp (100) of claim 11, wherein the electrode assembly comprises an even number of electrodes.

13. The MH lamp (100) of claim 11 , wherein the noble gas mixture comprises neon from 99.9% to 99.0% and argon from 0.1% to 1.0%.

14. The MH lamp (100) of claim 13, further comprising an outer envelope (352) around the quartz arc tube (102), wherein the outer envelope (352) contains neon gas having a same partial pressure as a partial pressure of the neon of the gas mixture.

15. The MH lamp (100) of claim 11, wherein each of the electrode leads is symmetric about a center point (CP) of the center portion (108) and longitudinal axis of the quartz arc tube (102).

16. The MH lamp (100) of claim 11 , wherein each of the lead electrodes (116) is opposed to each other and symmetrically located about a center of the discharge cavity (112).

17. The MH lamp (100) of claim 11, wherein each lead electrode of the electrode assembly has first and second ends (124, 104) and an electrode coil (130) situated at the second end (104) such that a backspace distance (101) between each electrode coil (130) and an adjacent end wall of the opposed end walls is the same, wherein each lead electrode (116) further extends past an outer periphery of the arc tube (102); and wherein the backspace distance (101) of each of the opposed lead electrodes is equal to or greater than 2 mm.

18. The MH lamp (100) of claim 11, wherein the electrode assembly consists of a pair of opposed lead electrodes (116), and wherein the MH lamp is configured to be started using the pair of opposed lead electrodes (116) when coupled to a probe-start ballast.

19. The MH lamp (100) of claim 11, wherein the discharge cavity (112) has an aspect ratio (AR) defined by a length of the discharge cavity between the opposed end walls (IL) to the ID, wherein the AR is between 2: 1 and 4: 1.

20. The MH lamp (100) of claim 11, wherein the MH lamp (100) is further started using voltage pulses having an amplitude between 3000 and 4000 volts provided by a pulse-start ballast.