JPS6164060A - Low wattage number metal halide lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to low wattage metal halide lamps, and more particularly to the construction and chemical filling of low wattage metal halide lamps.

[Prior art]

Generally, the metal halide discharge lamps currently available on the market are of medium or high wattage, i.e. 175-15
Consisting of 000 watt types. These high wattage metal halide lamps also have high efficacy. Efficacy is directly related to efficiency, conveniently defined as the ratio of total lumen output to input power, as expressed in lumens/watt. Furthermore, it is well known that the efficiency of a lamp tends to decrease as the wattage of the lamp decreases. Thus, in general, 1
It has been assumed that low wattage metal halide lamps of 0.00 watts or less would be completely unsatisfactory insofar as their efficiency was concerned.

Another common practice in medium and relatively high wattage metal halide lamps is to supply an inert fill gas to the outer envelope surrounding the arc tube. The inert fill gas was believed to prevent oxidation of the metal parts located within the outer envelope, increasing the breakdown voltage and preventing arcing. However, it has been found that the efficiency of the discharge lamp is considerably reduced due to the undesirable loss of heat due to convection that can occur due to the presence of an inert gas.

Known attempts to reduce this undesirable heat loss due to convection include the use of a glass cylinder surrounding the arc tube within a sealed outer envelope. However, structures containing gas fill within an outer envelope have undesirable convection.

Furthermore, these convection currents and associated heat losses exist even if a cylindrical arrangement of glass is employed.

Moreover, as the smallest known household commercialized metal halide discharge lamp, it is formed only for horizontal operation and approximately 3
There is a Fullvania 1F 5W lamp with a color temperature of 000'. The lamp has a phosphor-coated outer envelope that converts Uv radiation into visible red radiation. However, this lamp undesirably requires a relatively large and cumbersome floodlight device for adequate light distribution control and, in addition, has the disadvantage that it can only be operated in a horizontal position.

[Purpose and outline of the invention]

The aim of the present invention is to overcome these difficulties of the prior art.

A particular object of the present invention is to provide an improved metal halide discharge lamp having a relatively low wattage and reduced heat loss due to convection.

Another particular object of the invention is to be compact and about 3 o
It is an object of the present invention to provide a low wattage, high efficiency metal halide discharge lamp having a color temperature of o ocK.

Yet another particular object of the invention is to provide a chemical fill for a low wattage, relatively high efficiency metal halide discharge lamp.

These and other objects and advantages of the present invention, in accordance with one aspect of the present invention, include an external glass envelope that includes a pair of conductive wires that extend through the glass envelope and are sealed to the envelope. an arc tube having a pair of spaced apart electrodes disposed within the glass envelope and each electrically connected to one of a pair of conductive wires; 20:1~28:1
and a chemical filler comprising sodium iodide and scandium iodide in molar ratios in the range of .

〔Example〕

The present invention will be described below with reference to the drawings, with reference to preferred embodiments.

Referring to FIG. 1, a low wattage metal halide arc discharge lamp 5 includes an evacuated outer envelope 7. This evacuated outer envelope 7 is sealed to a glass stem member 9 to which an outer pace member 11 is fixed. A pair of conductive wires 13 and 15 extend through and are secured to the stem member 9 to provide a means for energizing the discharge lamp 5 by an external power source (not shown).

Within the vacuum of the exhaust envelope 7, a support member 17 is fixed to one of the conductive wires, extending y-parallel to the longitudinal axis of the lamp 5 and having a circular configuration near the top of the envelope 7. is forming. This circular form 19, together with the upper part of the envelope 7,
It serves to maintain support member 17 in proper alignment and resist deformation caused by external impacts.

A first strap member 21 is welded to the support member 17 and extends therefrom in a direction perpendicular to the longitudinal axis and the direction of the support member 17 .

A domed quartz sleeve or temperature equalization means 23 is provided, which sleeve or means has a pair of oppositely disposed notches 25 on an end 28 opposite the dome portion.
and 27. These notches 25 and 2
7 is configured to slide over a first strap member 21 which serves to support a domed quartz sleeve 23. A circular strap 29 also surrounds the domed quartz sleeve 25 near its domed portion and is attached to the support member 17.

Inside the temperature equalization means or dome-shaped quartz sleeve 23,
An arc tube 51 is provided containing a chemical fill containing elemental scandium and mercury, sodium iodide, scandium and cesium, and an inert gas. Luminous tube 31
has pinch seals at both ends 33 and 35 thereof. Metal foil members 37 and 69 are sealed to press seals 53 and 35, and conductive wires 41 and 45 are attached to the foil members 37 and 59 and extend outwardly from press seals 33 and 35. A flexible support member 45 is secured to one of the conductive wires 41 and to the support member 17. Further, a lead 47 is fixed to the other conductive wire 45 and passes through the dome-shaped portion of the dome-shaped quartz sleeve 23 .

Additionally, a flexible spring-like member 49 connects lead 47 to conductive wire 15 of the other conductive wire pair 13 and 15. A pair of getters 51 and 55 are fixed to the conductive wires 15 and 15, and serve to provide and maintain a vacuum within the evacuated envelope 7 and domed quartz sleeve 23.

Regarding the arc tube 61, for example, about 40 to 150 W
A preferred configuration suitable for use with a metal halide lamp having dimensions in the range of 1.5 to 1.5 mm would have an inner diameter of about 10 fins and an arc length between electrodes 41 and 43 of about 14 fins. Also,
It will be appreciated that each end of arc tube 31 adjacent to and including press seals 65 and 35 is coated with white zirconium oxide paint to provide increased uniformity of wall temperature. Furthermore, about 14-17W/(m2
A wall load in the range of about 40 to 150 is preferred and about 40 to 150
It has been found that this can be achieved with a metal halide lamp having a size in the range of W and having the configuration described above.

Regarding the chemical filling in the form of the discharge lamp mentioned above,
The comparison graph in Figure 2 is based on the chromaticity coordinates of the standard chromaticity chart (
X and Y) are plotted above to illustrate various ratios of sodium iodide and scandium iodide. As can be easily seen on the graph, the molar ratio of sodium iodide to scandium iodide, which is closest to the highly desirable black body (BB) curve representing the output of an incandescent lamp, is approximately 2.
The molar ratio ranges from 0=1 to 28:1. More specifically, a sodium iodide: scandium iodide molar ratio of about 24=1 appears to be a highly desirable filling condition for metal halide discharge lamps. Furthermore, it is noted that the highly desirable sodium iodide to scandium iodide molar ratios discussed above are biased toward the preferred side (below the 88 curve) for general lighting applications.

Also illustrated in FIG. 3 are the color temperature (Tc) and approximate color rendering index (CRI) for the lamps described above having striking molar ratios. As will be appreciated, the above-mentioned preferred molar ratio of sodium iodide to scandium iodide of about 20:1 to 28:1 provides a desirable color temperature of about 3000° in a range not exceeding about 200°K. . Furthermore, a molar ratio of sodium iodide to scandium iodide of about 24=1 appears to closely approach the desired so o o CK color temperature.

Furthermore, the comparative graph in FIG.
, (CRI). Furthermore, a mole of about 24:1 approaches the highly desirable molar ratio of CRI index of 65.0, and a range of about 20=1 to 28:10 mole, 6
It does not vary more than about 2.0 above or below the preferred value of 5.0.

The lamp efficiencies at the various molar ratios of sodium iodide to scandium iodide mentioned above are also shown in FIG.

From this figure, it can be seen that at a molar ratio of sodium iodide to scandium iodide of about 24=1, it is about 100 lumens/W (LPW).
It can be seen that the desired efficiency is shown. Furthermore, this desired 100 LPW capacity remains substantially constant over a sodium iodide to scandium iodide molar ratio ranging from about 20:1 to 28:1.

Furthermore, r? of sodium iodide and scandium iodide in a molar ratio of about 24=10? A study was conducted to determine the dosage of H. Employing a lamp with an arc tube volume of about 1 (m5) and varying the salt dosage in the range of about 8 to 2 Qm9, a dosage of about 12 m9/cm3 yields the highest lumen/cm3 with a preferred molar ratio of about 24:1. Watts and color rendering W< (C
RI) was found to occur. It has been found that for dosages weighing less than about 12 m9, the desired color rendering index (CRI) cannot be sustained, while dosages greater than about 12 m9 result in poor lumen maintenance and short lamp life. Furthermore, a dosage of about 12 m';)/crrt3 was found to be suitable for lamps in the range of about 40-150 W.

Additionally, it has been found that the inclusion of cesium iodide in the lamp dosage improves the starting time of discharge lamps. When the above-mentioned lamp contains cesium iodide in the range of about 0°3 to tom9, when a dosage of about 0.51n9 is adopted, the starting of the lamp is on average about 1 to 1
It has been found that the shame factor can be reduced to a virtually instantaneous start (less than 1 second). Lower amounts of cesium iodide provided much less improvement in start-up time, while lower amounts tended to reduce lamp efficiency and warm color properties. Thus, a volume of about 1 crIL3 and about 40-150
A preferred dosage for a metal halide discharge lamp having a wattage in the W range was to include about 12 parts of sodium iodide, scandium and cesium in a molar ratio of about 24:1:0.6.

In addition to the components mentioned above, the following formula i.e. N (H,S'
) Cm9/crX ) = 7.7 D 1″
According to D = arc tube diameter (mm), a dose of about 100 micrograms/(7n5) of elemental scandium and elemental mercury and argon gas at a pressure of about 100 Torr will power the above metal halide lamp of about 40-150 W. It has been found suitable that discharge lamps of improved color temperature, starting ability, lifespan and efficiency are thus achieved at lower wattages than known ones.

The present invention has been described above with reference to preferred specific examples, but
It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention.

Figure 1 is a cross-sectional view of a low wattage metal halide discharge lamp of the present invention, Figure 2 is a chromaticity coordinate diagram for the molar ratio of sodium iodide to scandium iodide, and Figure 3 is a chromaticity coordinate diagram for the molar ratio of sodium iodide to scandium iodide. Figure 4 shows an example of the color temperature (TC) and color rendering index (Cl) of a low wattage metal halide discharge lamp at a 1:1 molar ratio of sodium iodide to scandium iodide. 1 is a comparison graph illustrating lumens per wattage.

5: Metal halide arc discharge lamp 7: Evacuated outer envelope 9 Glass stem member 11: Pace member 13. 15: Conductive wire 17: Support member 19: Circular form 21. 29 Ni strap 23: Domed quartz sleeve or temperature Equivalent means 25.
27: Arc tube in notch 3 63.35 Nibble seal part 37.39: Metal foil member 41.43: Conductive wire 45: Support member 47: Lead 49: Spring-like member 51.53 -)゛,ノ,-/FIG,1 LPW

Claims (22)

[Claims] (1) a sealed outer glass envelope; a pair of conductive wires penetrating the glass envelope and sealed therein; and one of the pair of conductive wires disposed within the glass envelope. an arc tube having a pair of spaced apart electrodes each electrically connected to the arc tube and comprising sodium iodide and scandium iodide in a molar ratio ranging from about 20:1 to 28:1; Low wattage metal halide discharge lamps containing chemical fillings. (2) A low wattage metal halide discharge lamp according to claim 1, wherein the chemical fill includes cesium iodide, elemental mercury, elemental scandium and an inert gas. 3. The low wattage metal halide discharge lamp of claim 1, wherein said chemical fill comprises sodium iodide, scandium and cesium in a molar ratio of about 24:1:0.6. (4) A low wattage metal halide discharge lamp according to claim 1 having a size in the range of about 40-150W. 5. The low wattage metal halide discharge lamp of claim 1 including an evacuated sealed glass envelope and temperature equalization means disposed within the glass envelope surrounding the arc tube. (6) As the chemical filler, about 0.5 mg/cm^3
2. A low wattage metal halide discharge lamp as claimed in claim 1, comprising a weight of cesium iodide. (7) containing cesium iodide as the chemical filler, wherein the sodium iodide, scandium and cesium are about 1
A low wattage metal halide discharge lamp according to claim 1, having a weight of 2 mg/cm^3. 8. The low wattage metal halide discharge lamp of claim 1, wherein said chemical fill includes elemental scandium with a weight in the range of about 90 to 110 micrograms/cm^3. 9. The low wattage metal halide discharge lamp of claim 1, wherein said chemical fill comprises an inert gas at a pressure of about 100 torr. (10) As the chemical filler, the following formula, that is, N(H
g) (mg/cm^3) = 7.7D^1^/^7 The low wattage according to claim 1, which contains elemental mercury in a weight according to D = arc tube inner diameter (mm). Metal halide discharge lamp. (11) Approximately 3000 within a range not exceeding approximately 200°K above and below
A low wattage metal halide discharge lamp according to claim 1 having a color temperature of °K. 12. The low wattage metal halide discharge lamp of claim 1 having a Color Rendering Index (CRI) of about 65 with no more than about 2.0. 13. The low wattage metal halide discharge lamp of claim 1, wherein said arc tube has a wall load in the range of about 14-17 W/cm^2. (14) an evacuated outer envelope, a pair of conductive wires penetrating the envelope and sealed therein, and a pair of conductive wires disposed within the envelope and connected to one of the pair of conductive wires 1 each electrically connected
an arc tube having a pair of spaced electrodes; a domed quartz sleeve fitted over the arc tube within the envelope; containing iodide, and the sodium iodide and scandium iodide are about 2
A metal halide discharge lamp in the range of about 40 to 150 watts comprising a chemical fill in said arc tube having a molar ratio in the range of 0:1 to 28:1. (15) The metal halide discharge lamp of claim 14, wherein said sodium iodide, scandium and cesium have a molar ratio of about 24:1:0.6. (16) The metal halide discharge lamp according to claim 14, wherein the cesium iodide is contained in an amount of about 0.5 mg/cm^3. (17) The metal halide discharge lamp according to claim 14, wherein the iodides of sodium, scandium, and cesium are contained in an amount of about 12 mg/cm^3. (18) Claim 1 containing the element scandium in an amount in the range of about 90 to 110 micrograms/cm^3
4. The metal halide discharge lamp according to item 4. 19. The metal halide discharge lamp of claim 14, wherein said inert gas is argon at a pressure of about 100 Torr. (20) As the chemical filler, the following formula, that is, N(Hg
) (mg/cm^3) = 7.7D^1^/^7 here D
15. The low wattage metal halide discharge lamp according to claim 14, comprising an amount of elemental mercury according to: = arc tube inner diameter (mm). (21) Approximately 3000 within the range of approximately 200°K above and below
15. A metal halide discharge lamp according to claim 14, having a color temperature of °K. 22. The low wattage metal halide discharge lamp of claim 14, wherein said arc tube has a wall load in the range of about 14-17 W/cm^2.