JP5045065B2 - Ceramic metal halide lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a fluorescent lamp specified by JIS Z9112 to emit light in a chromaticity range equivalent to daylight white color or daylight color without degrading luminous efficiency and a color rendering property. <P>SOLUTION: Respective halides of dysprosium, holmium and thallium are filled as metal halides in a light emitting tube formed such that the coldest part temperature of a light emitting part in a lighting state is above 800&deg;C and the thickness of the light emitting part is average thickness &plusmn;20%; a halide of cesium is selectively filled therein; and when it is assumed that the filled molar number of sodium halide, that of dysprosium and that of holmium are 0, M<SB>D</SB>and M<SB>H</SB>, respectively, the total filled molar number M<SB>C</SB>of other alkaline metals and the filled molar number M<SB>T</SB>of thallium are specified by expressions: 0&le;M<SB>C</SB>/(M<SB>D</SB>+M<SB>H</SB>)&le;0.4, and 0.1&le;M<SB>T</SB>/(M<SB>D</SB>+M<SB>H</SB>)&le;0.5 when cesium is present. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a ceramic metal halide lamp mainly used for general illumination.

In recent years, high-pressure metal vapor discharge lamps using translucent ceramic arc tubes instead of quartz have been commercialized as arc tube materials for high-pressure metal vapor discharge lamps used in general lighting applications.
Translucent ceramics have higher heat resistance and corrosion resistance than quartz, so by making the wall load of the arc tube higher than the wall load of the quartz arc tube, a high-pressure metal vapor discharge lamp using a quartz arc tube High efficiency, high color rendering, and long life compared to the LED, and the variation of the light source color is very small because the variation of the shape is very small compared to the quartz arc tube. Since the light source color is white when used as an indoor lighting, it is widely used for indoor lighting in stores and the like centering around 150 W or less.

  And from the viewpoint of energy saving, further higher efficiency is required. To achieve this, structurally, the type that combines 3 parts or 5 parts has changed to a type in which the thin tube and light emitting part are integrally molded. ing.

  As for the luminescent color, the conventional ceramic metal halide lamps had many bulb colors to white color with a correlated color temperature of 3000K to 4500K, but the market demands a daylight white color with a correlated color temperature of about 5000K or a daylight color of about 6500K. ing.

  In a conventional high color rendering metal halide lamp, means for using a dysprosium-thallium-cesium system or a dysprosium-neodymium-cesium system as a light emitting metal are known as means for realizing a relatively high color temperature. .

  In such a metal halide lamp using a rare earth element such as dysprosium, it is necessary to use molecular light emission of the enclosed rare earth halide in order to obtain a desired light color.

In general, in order to effectively use the molecular emission of rare earth halides, an alkali metal element such as sodium or cesium having a low vapor pressure but a low excitation voltage is enclosed several times more than the rare earth metal element in a molar ratio. , Make a complex molecule of alkali metal element, rare earth element and halogen.
This composite molecule has a vapor pressure far higher than that of a rare earth halide alone and has the effect of thickening the arc due to the effect of an alkali metal element having a low excitation voltage, so that the rare earth halogen said to emit light in a relatively low arc temperature region. The molecular emission of the compound can be significantly increased.
In general, increasing the encapsulated mole ratio of alkali metals such as cesium Cs has the effect of thickening the arc and suppressing arc swing and stabilizing lighting, while conversely, if the encapsulated mole ratio is small, the arc becomes thin and the arc swing is reduced. It is known that there is a tendency to occur or cause arc bending, or in some cases, the lamp voltage to rise excessively and cause a disappearance that suddenly disappears while the lamp is on.
Therefore, in a normal metal halide lamp, in order to achieve the objectives of “suppressing arc fluctuation” and “high color rendering”, for example, in the conventional lamp, cesium is encapsulated in a large amount as an alkali metal.

However, when a large amount of an alkali metal element having a low excitation voltage is sealed in this way, another problem becomes apparent. For example, when cesium halide is encapsulated as an alkali metal, cesium itself consumes energy because it emits infrared rays, causing the problem that the luminous efficiency of visible light, which is important for general illumination, does not increase, and features of ceramic metal halide lamps In addition to hindering the realization of the high luminous efficiency, the molecular emission of the rare earth metal is too strong and the color temperature is lowered.
Therefore, defining the relatively high molar ratio of cesium Cs for the same reason also in Patent Document 1 described below and 0.5M _A ~1.0M _A.
Further, if a large amount of sodium halide having a main emission wavelength of only about 589 nm is encapsulated as an alkali metal, the luminous efficiency is increased, but the color temperature is lowered, so that it is difficult to realize a high color temperature.

  Conventionally, when encapsulating rare earth elements to obtain high color rendering, dysprosium, thulium, and holmium are said to have almost the same effect. If these are appropriately selected from these three types and encapsulated in the lamp, Although it has been said that there is a desired effect on the color rendering properties, the emission spectra of these three elements are not the same, and the desired level of high color rendering as required for ceramic metal halide lamp products is achieved. When trying to achieve chromaticity, it is necessary to use these three elements properly.

On the other hand, Patent Document 1 discloses a rare gas for starting, mercury, terbium halide (TbX ₃ ), thallium halide (TlX), and cesium halide (CsX) inside the arc tube of a ceramic metal halide lamp made of a translucent material. ) is sealed, and halogenated Disuburoshiumu _(dyx 3), halogenated holmium _(Hox 3), erbium halides _(ERX 3), by sealing at least one halogenated thulium (TMX _3), the color temperature Is disclosed in a range of 5700-7100K corresponding to the daylight color of the fluorescent lamp defined in JIS standard Z9112.
JP 2004-158218 A

FIG 3 of Patent Document 1, the ceramic metal halide lamp of 400W constituted by Dy-Tb-Tl-Cs- I series enclosure, when the total number of moles of the terbium Tb and dysprosium Dy was _{M A} , the color when the molar ratio of terbium Tb is that 0.15 M _a, 0.25M _a, in each case of 0.4 M _a, varying the molar ratio of cesium Cs in 0.5M _a ~1.0M _a The change in temperature is shown.
According to FIG. 3, in the color temperature range from 5000K to 11000K, the lower the terbium halide encapsulation ratio, the lower the color temperature, and the lower the cesium halide encapsulation ratio, the lower the color temperature.
Still referring to FIG. 2, in lamps which are 0.15 M _A molar ratio of thallium Tl in the specification, it is understood that if terbium Tb enclosed amount to zero can below the color temperature 5000K.

However, when the inventors made a prototype of a low-power lamp having a color temperature of 4600K to 5500K and a rated power consumption of 150 W, which is equivalent to the daylight white color of the fluorescent lamp specified in JIS standard Z9112, instead of daylight color, The efficiency did not reach the 85 lm / W required for a high-efficiency lamp and was 80 lm / W or less.
That is, the cesium Cs enclosed in the arc tube lowers the luminous efficiency, and the rated power consumption is as low as 150 W. Therefore, it is considered that the luminous efficiency is further lowered.
For this reason, if the encapsulation ratio of cesium Cs is reduced, the luminous efficiency can be increased, but in reality, as described above, it cannot be made below a certain lower limit value in order to stabilize the arc, It is not practical as a daylight / daylight ceramic metal halide lamp that is expected to have high efficiency and high color rendering.

  Therefore, the present invention can emit light at a color temperature of 4600 K or higher without deteriorating the light emission efficiency and color rendering, and thereby, the chromaticity range equivalent to the daylight white color or daylight color of the fluorescent lamp defined in JIS standard Z9112. It is a technical challenge to provide a lamp.

In order to solve this problem, according to the present invention, a light emitting part in which a metal halide, mercury, and a starting rare gas are sealed, and a capillary through which a pair of electrode assemblies arranged at both ends thereof are inserted, are formed of ceramic. In the ceramic metal halide lamp provided with the luminous tube, the metal halogen is disposed in the luminous tube in which the coldest temperature of the light emitting portion in the lighting state is 800 ° C. or more and the thickness of the light emitting portion is an average thickness of ± 20%. As halides, only dysprosium, holmium, thallium and cesium halides are encapsulated, the number of moles of sodium halide encapsulated is defined as 0, and the number of moles of dysprosium and holmium encapsulated is M _D and M _{H, respectively.} and when, sealed moles M _C and encapsulating moles M _T thallium cesium, the range of values calculated by the respective following formulas Ceramic metal halide lamp, characterized in that it is defined.
[Formula] 0 < M _C / (M _D + M _H ) ≦ 0.4
0.1 ≦ M _T / (M _D + M _H ) ≦ 0.5

According to the present invention, the thickness of the light emitting part is suppressed to an average thickness within ± 20%, and the coldest part of the light emitting tube is formed to be 800 ° C. or higher. Is maintained in such a state that the dysprosium and holmium rare earth metal halides can sufficiently evaporate, and as a result, a stable arc can be generated.
According to the experiment, the vapor pressure at this time was 50 to 100 Pa suitable for light emission.

In addition, according to the inventors' experiments, in order to simultaneously achieve a high color temperature of 4600 K or higher, high color rendering, and high efficiency, atomic emission of a rare earth metal (short wavelength region) and molecular emission of a rare earth metal halide ( It has been found necessary to balance the long wavelength region) at a suitable ratio.
Atomic emission requires a high temperature and therefore occurs at the center of the arc, while molecular emission occurs near the arc edge at a relatively low temperature.
Therefore, if the arc is thin, the spatial region in which molecular light emission occurs is small, so the atomic emission ratio is large, and if the arc is thick, the spatial region in which molecular light emission is large is large, so the molecular light emission ratio is large.
Here, since thallium has the effect of thickening the arc, in the present invention, by encapsulating a required amount of thallium, an arc temperature region is ensured in which the rare earth metal halide emits molecules, and the ratio of molecular emission is increased. The thickness could be adjusted so as not to be too high, and high color rendering properties could be realized.

In this case, the Rukoto added a small amount of cesium, the following effects can be obtained.
In other words, the effect of molecular light emission of rare earth metals is superior to cesium rather than thallium, and if the amount of encapsulation is as specified in the present invention, rather than a decrease in the luminous efficiency of visible light due to infrared emission. The degree of increase in luminous efficiency due to molecular emission of rare earth halides is large, and therefore a lamp with high luminous efficiency can be obtained.
Also, if you try to optimize the emission of rare earth metals by increasing or decreasing only the amount of thallium enclosed, it may be necessary to consider the color change due to the emission of thallium itself, in this case the optimization work becomes troublesome, It is convenient to add a small amount of cesium to achieve high efficiency and high color rendering.

Thus, since it is possible to generate a stable arc by evaporating the halide of the rare earth metal without enclosing an alkali metal such as sodium or cesium, not only can molecular light emission be utilized, A lamp having a high color temperature can be obtained by utilizing atomic emission.
In particular, in the present invention, sodium that causes a decrease in the correlated color temperature is not enclosed, so that the decrease in the correlated color temperature can be prevented and light can be emitted in daylight color and daylight white.
Furthermore, since the amount of cesium encapsulated that causes a decrease in luminous efficiency can be reduced, the luminous efficiency can be maintained at 85 (lm / W) or more.
As a result, the lamp can emit light at a color temperature of 4600K or higher while maintaining high luminous efficiency and high color rendering.

According to claim 2, the lamp has a color temperature of 4600-5500K, and according to claim 3, the lamp has a color temperature of 5700-7100K.
As a result, a ceramic metal halide lamp having a light emission color in the chromaticity range equivalent to the daylight white color or daylight color of the fluorescent lamp defined in JIS standard Z9112 can be realized.

In this example, in order to achieve the purpose of allowing light emission in a color temperature range of 4600K or higher without reducing the light emission efficiency and color rendering of the ceramic metal halide lamp, Only the dysprosium, holmium, thallium and cesium halides are encapsulated as the metal halide in the arc tube in which the part temperature is 800 ° C. or more and the thickness of the light emitting part is formed with an average thickness of ± 20%. When the number of moles of sodium halide enclosed is defined as 0, and the number of moles of dysprosium and holmium is M _D and _MH , respectively, the number of moles of cesium sealed M _C and the number of moles of thallium sealed M _T is defined as a range value calculated by the following equation.
[Formula] 0 < M _C / (M _D + M _H ) ≦ 0.4
0.1 ≦ M _T / (M _D + M _H ) ≦ 0.5

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is an explanatory view showing the main part of a metal halide lamp according to the present invention, FIG. 2 is an overall outer tube diagram thereof, FIG. 3 is a graph showing a change in luminous efficiency depending on the amount of cesium enclosed, and FIG. Graph showing change in evaluation index Ra, FIG. 5 is a graph showing change in emission color depending on the amount of dysprosium and holmium enclosed, and FIG. 6 is a graph showing change in emission color on the xy chromaticity diagram of each example. FIG. 7 is a table showing the amount of light-emitting metal enclosed.

The ceramic metal halide lamp 1 of this example is configured such that an arc tube 2 formed of a translucent ceramic such as alumina is accommodated in an outer sphere 13 having a base 12 at one end.
The arc tube 2 is formed by integrally forming a light emitting portion 3 and capillaries 4A, 4B with a powdered compact of translucent alumina, and inside the light emitting portion 3, a metal halide, mercury, and a starting rare gas are enclosed. Yes.
Further, a pair of electrode assemblies 6A and 6B having electrodes 5 and 5 are inserted into the capillaries 4R and 4L formed at both ends of the substantially spheroidal light emitting unit 3, and both ends of the capillaries 4R and 4L are connected to each other. The electrode assemblies 6A and 6B are fixed in place in the capillaries 4R and 4L at the same time as being hermetically sealed by the frit glass having electrical insulation.

The support disks 17 and 17 are fixed to the two support columns 15 and 16 erected on the stem 14 of the base 12 at a predetermined interval, and the capillaries 4R and 4L are inserted into the insertion holes formed at the centers thereof. The arc tube 2 is attached and supported, and a translucent sleeve 18 is fixed to the disks 17 and 17 so as to surround the light emitting portion 3.
Furthermore, the power supply leads 7 and 7 protruding from the ends of the capillaries 4R and 4L are electrically connected to the base 12 by being welded directly to the support columns 15 and 16 or via the nickel ribbon wires 19 and 19, respectively. ing.

The arc tube 2 is formed such that the coldest portion temperature in the lighting state is 800 ° C. or more, and the thickness of the light emitting portion 3 excluding the capillaries 4R and 4L from the arc tube 2 is an average thickness of ± 20%.
In order to set the coldest part temperature to 800 ° C., in this example, light emission is performed so that the perfect load is 25.6 W / cm ² (rated power consumption 150 W, inner surface area 5.86 cm ² , arc tube inner volume 1.2 cc). Part 3 is formed.

Further, the light emitting section 3 is formed in a substantially spheroid shape, and its thickness is formed to an average thickness of ± 20%. In this example,
Average wall thickness t _av = 8.5mm
Whereas
Minimum thickness t _min = 0.78mm
Maximum wall thickness _tmax = 0.98mm
And
Allowable minimum wall thickness t _av -20% = 0.68mm
Maximum allowable wall thickness t _av + 20% = 1.02 mm
Therefore, it is formed within an allowable thickness dimension of an average thickness ± 20%.
Thereby, the tube wall load required for maintaining the coldest part temperature in the arc tube light-emitting part 3 at 800 ° C. or more can be reduced, and the temperature difference in the light-emitting part can be reduced as compared with the prior art. For this reason, the chemical reaction rate between the rare earth metal iodide and the material constituting the light emitting portion inner wall surface can be kept low, and the lamp life can be extended.
Among the ceramic metal halide lamps, there is an arc tube in which the light emitting portion and the capillary portion are processed by dividing them into three-piece or five-piece parts, and these are assembled by shrink fitting by shrinkage during arc tube sintering. In this type of assembled arc tube, the end of the light emitting part is 1.5 times thicker than the vicinity of the center of the light emitting part in order to ensure the mechanical strength when parts are fitted. Is common.
In this case, since the heat radiation of the thick part is larger than elsewhere, the temperature of the thick part is difficult to rise, and in order to maintain the temperature of this part at 800 ° C. or higher, the tube wall load must be set high. As a result, the temperature difference in the light emitting part is increased, the chemical reaction rate between the rare earth metal iodide and the material constituting the inner wall of the arc tube is increased in the high temperature part, the erosion of the inner wall surface of the arc tube is accelerated, and the lamp life is shortened. This causes the problem.
However, if the variation in the thickness of the light emitting portion is suppressed within an average thickness of ± 20%, even the assembled arc tube has the same effect as the present invention.

Further, the light emitting portion 3 is formed in a substantially spheroidal, the maximum diameter d, the distance between electrodes when the A _L, is the ratio d / A _L,
0.8 ≦ d / A _L ≦ 1.5
In this example, the range is selected so that
Distance between electrodes A _L = 10.0 (mm)
Maximum diameter d = 12.5 (mm)
Designed to.
Setting the value of d / _AL as described above is not always necessary to obtain the effect of the present invention, but experience shows that the temperature distribution in the light emitting part is within a good range as long as it is within this value range. In addition, problems such as cracks in the light emitting portion are unlikely to occur over a long period of time during the lamp life.
The d / A _L lamp having a light emitting portion of less than 0.8 elongated, but results in a coolest portion in the vicinity of the light emitting portion end closer to the lower electrode when lit light axes perpendicular, the outermost Although it is not technically impossible to design the maximum temperature relatively low while maintaining the cold part at 800 ° C. or higher, it is quite difficult and the design margin is reduced.
In the lamp having a light emitting portion of the thick and short shape d / A _L exceeds 1.5, but results in a coolest portion in the vicinity of the light emitting portion lower center when lit optical axis in the horizontal, the coldest In order to maintain the part at 800 ° C. or higher, it is necessary to set the tube wall load high. As a result, the temperature difference in the light emitting part increases, and in particular, the inner wall surface of the arc tube near the upper center of the light emitting part becomes high temperature, and the chemical reaction rate between the rare earth metal iodide and the material constituting the inner wall surface of the arc tube increases. The erosion of the lamp is accelerated and the lamp life is shortened.

Further, only dysprosium, holmium, thallium and cesium halides are encapsulated as metal halides, and the number of moles of sodium halide encapsulated is defined as 0.
Also, when the sealed moles of dysprosium and holmium and respectively M _D and M _H, inclusion moles M _T encapsulation moles M _C and thallium cesium, the range of values calculated by the respective following formulas Stipulated.
[Formula] 0 < M _C / (M _D + M _H ) ≦ 0.4
0.1 ≦ M _T / (M _D + M _H ) ≦ 0.5

In addition, for the enclosed molar ratio M _D / _MH of dysprosium and holmium, when the emission color is the daylight color of a fluorescent lamp specified in JIS standard Z9112,
0.2 ≦ M _D / M _H ≦ 0.4
If the light emission color is the daylight white of the fluorescent lamp specified in the same standard,
0.4 <M _D / M _H ≦ 0.6
It is stipulated in.

3, thallium Tl, dysprosium Dy, inclusion moles of the luminescent metal holmium Ho fixing is a graph showing changes in luminous efficiency when changing the enclosed moles M _C cesium Cs.
In this example, the number of moles M _D , M _H and M _T of dysprosium Dy, holmium Ho, and thallium Tl are set as follows.
M _D ≈1.4 × 10 ⁻³ mol
M _H ≈2.8 × 10 ⁻³ mol
M _T ≈0.9 × 10 ⁻³ mol
Further, the inclusion moles M _C cesium Cs, was varied in the following range.
_{0 ≦ M C / (M D} + M H) ≦ 0.5
According to this, 0 ≦ M _C / emission efficiency when the _{(M D + M H) ≦} 0.4 is not less 85 [lm / W] or more, 0.4 _<M C _/ in _(M D + M _H) Sometimes the luminous efficiency decreases to less than 85 [lm / W].
Further, 0 ≦ M in the range of _{C / (M D + M H} ) ≦ 0.2 continue to increase light emitting efficiency according to increasing cesium, but when it exceeds 0.2, increase even emit more cesium Efficiency will decrease.
This is because cesium Cs has two types of effects: “increase the vapor pressure of rare earth metals” and “decrease the luminous efficiency of visible light”, but the range of 0.2 or less has the effect of the former, and the cesium ratio is It is thought that the influence of the latter becomes dominant when it becomes more than that.
This tendency was the same even when the number of moles of other metals encapsulated was changed.
Therefore, from this result, in order to maintain the luminous efficiency 85 [lm / W] or more high efficiency, enclosed moles _{M C} cesium Cs _{is, 0 ≦ M C / (M} D + M H) ≦ 0.4 It is led to be.

4, cesium Cs, dysprosium Dy, inclusion moles of the luminescent metal holmium Ho fixed, changes in the general color rendering index Ra and the luminous efficiency when changing the enclosed moles M _T thallium Tl It is a graph which shows.
In this embodiment, dysprosium Dy, holmium Ho, enclosed moles _M D cesium _Cs, M H, a _{M C} were as follows.
M _D ≈1.4 × 10 ⁻³ mol
M _H ≈2.8 × 10 ⁻³ mol
M _C ≈1.2 × 10 ⁻³ mol
In addition, the number of moles M _T enclosed in thallium Tl was changed in the following range.
0 ≦ M _T / (M _D + M _H ) ≦ 0.6
According to this, the average color rendering index Ra ≧ 90 when 0 ≦ M _T / (M _D + M _H ) ≦ 0.5, and the average color rendering when 0.5 <M _T / (M _D + M _H ). The evaluation number Ra <90, and beyond that, the average color rendering evaluation number Ra decreases even if the thallium filling amount is increased.
Also, the emission efficiency decreases as the value of M _T / (M _D + M _H ) decreases, and the emission efficiency is less than 85 [lm / W] when M _T / (M _D + M _H ) <0.1. It turns out that it falls.
These tendencies were the same even when the number of moles of other metals contained was changed.
Therefore, from this result, the optimum number of moles M _T of thallium enclosed is derived from the following range.
0.1 ≦ M _T / (M _D + M _H ) ≦ 0.5

FIG. 5 is a graph showing the change in color temperature when the number of moles of cesium Cs and thallium Tl is fixed and the mole ratio M _D / _MH of dysprosium Dy and holmium Ho is changed.
In this example, the number of moles of encapsulated M _C and M _T of cesium Cs and thallium Tl is as follows.
M _C ≈1.2 × 10 ⁻³ mol
M _T ≈0.9 × 10 ⁻³ mol
Also, dysprosium Dy, inclusion molar ratio _M D / _{M H} holmium Ho varied as follows.
0.1 ≦ M _D / M _H ≦ 0.7
According to this, when 0.2 ≦ M _D / M _H ≦ 0.37, the color temperature is 5700-7100 K corresponding to the daylight color of the fluorescent lamp defined in JIS standard Z9112, and 0.4 ≦ M _D When / M _H ≦ 0.6, the value was 4600-5500 K corresponding to the daytime white color of the same standard, and this tendency was the same even when the number of moles of other metals enclosed was changed.

FIG. 6 is an xy chromaticity diagram showing emission colors when seven types of metal halide lamps 1 in Examples 1 to 5 and Comparative Examples 1 and 2 are turned on for 100 hours.
FIG. 7 shows the number of moles and molar ratio of the metal as the halide of each of the lamps of Examples 1 to 5 and Comparative Examples 1 and 2.

The temperature of each part of the light emitting unit 3 was measured by dividing the surface of the light emitting unit 3 into 1 mm ² square elements using an infrared radiation thermometer and measuring the temperature of each element.
Moreover, the outer bulb | ball 13 was removed, the light emission part 3 was lighted in the vacuum chamber, and the measured value of the radiation thermometer was calibrated using the value measured with the thermocouple.

In any case, when the ceramic metal halide lamp 1 is lit up in a vertical direction so that the base 12 faces upward, the coldest part of the arc tube is the boundary position between the capillaries 4R on the base 12 side and the light emitting part 3 P ₁ and in each case, the temperature was around 810 ° C.
Further, a ceramic metal halide lamp 1, when lit Tilt horizontally, coldest portion of the arc tube is the maximum diameter lower position P ₂ of the light emitting portion 3, the temperature was around 823 ° C..

Example 1 was dysprosium Dy, holmium Ho, thallium Tl, enclosed moles _M D cesium _Cs, M _H, M T, as follows the _{M C.}
M _D ≈1.6 × 10 ⁻³ mol
M _H ≈2.8 × 10 ⁻³ mol
M _T ≈0.9 × 10 ⁻³ mol
M _C ≈1.2 × 10 ⁻³ mol
Examples 2 and 3, respectively encapsulated moles M _C cesium Cs, except that the following are the same as in the first embodiment.
M _C ≒ 1.5 × 10 ^-3 mol
M _C ≈0.0 × 10 ⁻³ mol
In each of Examples 1 to 3, the emission color is in the daylight white range of the fluorescent lamp specified in JIS standard Z9112, the average color rendering index Ra = 94 to 95, luminous efficiency = 85 [lm / W ]Met.
In addition, the total number of moles of metal encapsulated as the halide of Example 1 is 6.5 × 10 ⁻³ mol, and the total number of moles enclosed per unit volume of the arc tube 2 is 5.410 ⁻³ mol / cc. Become. This value was the optimum amount of filling in the arc tube and lighting conditions used in this example, but even if the amount of filling was changed from 0.5 to 2 times this value, the light emission characteristics were not so much affected. I did not receive it.
When the shape of the arc tube and other lamps is the same as in the present embodiment, the total encapsulated mole of metal as a halide is used in a lamp in which the coldest part temperature of the light emitting part 3 is 800 ° C., the lower limit defined in the present invention. A better result is obtained if the number is larger than the amount shown in Example 1. On the other hand, in a lamp in which the coldest part temperature of the light emitting part 3 is set higher, a better result is obtained when the total number of moles of metal enclosed as the halide is smaller than the amount shown in Example 1. However, when the lamp is turned on under conditions where the coldest part temperature exceeds 950 ° C., the arc tube maximum temperature may exceed 1200 ° C., and in this case, the inner wall surface of the arc tube 2 deteriorates rapidly, causing several In 100 hours, the arc tube 2 cracks and becomes an extremely short-life lamp.

For Comparative Example 1, except that the following inclusion moles M _C of cesium, the same as in Example 1.
M _C ≈2 × 10 ⁻³ mol
In this case, M _C / (M _D + M _H ) = 0.44 in terms of molar ratio, exceeding 0.4 in terms of molar ratio, and the y value of the emission color is shifted in the direction of increasing, and the average color rendering index Ra Is 90, but the luminous efficiency is reduced to 80 [lm / W].
For Comparative Example 2, except that the following inclusion moles M _T of data helium, it is the same as the first embodiment.
M _T ≈2.4 × 10 ⁻³ mol
In this case, the molar ratio M _T / (M _D + M _H ) = 0.55, which greatly exceeds 0.25 and the luminous efficiency is as high as 90 [lm / W], but the y value of the luminescent color is high. The average color rendering index Ra is also reduced to 85.

Example 4, except that the following inclusion moles M _D of dysprosium are the same as in Example 1.
M _D ≒ 1.0 × 10 ^-3 mol
In this case, the molar ratio M _D / M _H = 0.36, less than 0.40, the emission color is the daylight color range of the fluorescent lamp defined in JIS standard Z9112, and the average color rendering index Ra = 90, Luminous efficiency = 85 [lm / W].

Example 5 shows an example in which a 360 W ceramic metal halide lamp is designed. Although the external shape is almost similar to the 150 W ceramic metal halide lamp shown in Example 1,
The light emitting part 3 formed with the coldest part temperature in the lighting state of 800 ° C. or more and the light emitting part thickness of an average thickness of ± 20% has a maximum diameter d = 19 mm, an interelectrode distance A _L = 22 mm, an inner surface area is 19.15cm ^2, the tube wall load has become a 18.8W / cm ^2. The inner volume of the arc tube 2 was 7.1 cc.

Dysprosium Dy encapsulated in the light emitting portion 3, holmium Ho, thallium Tl, enclosed moles _M D cesium _Cs, M _H, M T, was as follows _{M C.}
M _D ≈5 × 10 ⁻³ mol
M _H ≈11.9 × 10 ⁻³ mol
M _T ≈3.5 × 10 ⁻³ mol
M _C ≈2.7 × 10 ⁻³ mol
In this case, the emission color was in the daylight white range of the fluorescent lamp specified in JIS standard Z9112, the average color rendering index Ra = 95, and the luminous efficiency = 90 [lm / W].

  As described above, the present invention can be applied to a ceramic metal halide lamp mainly used for general illumination.

Explanatory drawing which shows the principal part of the metal halide lamp concerning this invention. The entire outer pipe diagram. The graph which shows the change of the luminous efficiency by the amount of cesium enclosure. The graph which shows the change of the average color rendering evaluation index Ra by the thallium enclosure amount. The graph which shows the change of the luminescent color by the enclosure amount of dysprosium and holmium. The graph which shows the luminescent color change on the xy chromaticity diagram of each Example. The table | surface which shows the enclosure amount of a luminescent metal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic metal halide lamp 2 Light emission tube 3 Light emission part 4A, 4B Capillary 5, 5 Electrode 6A, 6B Electrode assembly 7, 7 Power supply lead

Claims (3)

In a ceramic metal halide lamp provided with a light emitting portion in which a metal halide, mercury and a starting rare gas are sealed, and a capillary inserted through a pair of electrode assemblies disposed at both ends of the light emitting portion, the arc tube is formed of ceramic.
In the arc tube in which the coldest part temperature of the light emitting part in the lighting state is 800 ° C. or more and the thickness of the light emitting part is formed with an average thickness of ± 20%, as the metal halide, dysprosium, holmium, thallium and Only each halide of cesium is enclosed, and the number of moles of sodium halide enclosed is defined as 0,
Defining a sealed moles of dysprosium and holmium when the respective M _D and M _H, enclosed moles M _C and encapsulating moles M _T thallium cesium, to a value in the range calculated by the respective following formulas A ceramic metal halide lamp characterized by
[Formula] 0 < M _C / (M _D + M _H ) ≦ 0.4
0.1 ≦ M _T / (M _D + M _H ) ≦ 0.5
The enclosed molar ratio M _D / _MH of the dysprosium and holmium is
0.4 ≦ M _D / M _H ≦ 0.6
The ceramic metal halide lamp according to claim 1, as defined in claim 1. The dysprosium and encapsulation molar ratio _M D / _{M H} of holmium _{0.2 ≦ M D / M H ≦} 0.37
The ceramic metal halide lamp according to claim 1, as defined in claim 1.

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