JP2006134704A - High-pressure metallic vapor discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance lamp efficiency and color rendering of a high-pressure metallic vapor discharge lamp using a ceramic light-emitting tube for indoor illumination such as in a store and an outdoor illumination such as in the street, and at the same time, to keep its light source colors within the range of warm white, white and daylight white, and further, to prevent fade-out or the like of a lamp due to rise of a lamp voltage. <P>SOLUTION: Cerium halide, sodium halide, and calcium halide are sealed in as light-emitting substances inside a light-emitting part 2 of a ceramic light-emitting tube equipped with an electrode 5, 5 at each end, in which, a mol composition ratio NaI/CeI<SB>3</SB>of the sodium halide to the cerium halide is set within the range of 8 to 95, and a mol composition ratio CaI<SB>2</SB>/CeI<SB>3</SB>of the calcium halide to cerium halide within the range of 5 to 60. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a high-pressure metal vapor discharge lamp that emits light by discharge in a mixture of a metal vapor and a halide dissociation product.

In recent years, high-pressure metal vapor discharge lamps using ceramic arc tubes, such as translucent polycrystalline alumina ceramic tubes, have been rated in place of the conventionally used quartz arc tubes. Commercialized mainly with lamp power of 150W or less. High-pressure metal vapor discharge lamps using arc tubes made of ceramic materials that have better heat resistance and corrosion resistance than quartz use quartz arc tubes by making the wall load of the arc tube higher than that of quartz arc tubes. Compared with conventional high pressure metal vapor discharge lamps, it has excellent characteristics such as high efficiency, high color rendering, and long life, and ceramic arc tube has less shape variation than quartz arc tube. Since there is very little color variation and the light source color is white, it is becoming popular for indoor lighting in stores and the like.

Although currently marketed high-pressure metal vapor discharge lamps of 150 W or less using a ceramic arc tube have an average color rendering index (Ra) of 85 to 90, the lamp efficiency is approximately 90 ( However, there is almost no achievement of 100 (lm / W) or more, which is generally said to be high efficiency, and recently there has been a demand for further higher lamp efficiency from the viewpoint of energy saving. Yes. In addition, high-pressure metal vapor discharge lamps using ceramic arc tubes are required to have high wattage that can be mounted on higher ceilings indoors or used for outdoor lighting on streets, etc. In addition, there is a demand for an inexpensive mercury lamp ballast that can be turned on.

As a means for increasing the lamp efficiency, it is common to increase the light emission of the rare earth element halide enclosed in the light emitting part by increasing the tube wall load of the arc tube, but the ceramic arc tube is made of quartz. Since the tube wall load is higher than that of the arc tube, if the tube wall load is further increased to increase the emission of halides of rare earth elements, the re-ignition voltage will increase, and the lamp will extinguish accordingly. Since the generated voltage becomes high, the lamp may be extinguished in a lighting time much shorter than the rated life, or in the worst case, it may be extinguished at the beginning of lighting.

In addition, when the tube wall load of the arc tube is increased, the temperature of the arc tube at the time of lighting increases, and particularly the heat load of the light emitting part increases. Therefore, the thermal load causes cracks in the arc tube with a lighting time much shorter than the rated life. Causes the lamp to become unsatisfactory, or the reaction between the ceramic forming the arc tube and the luminescent material enclosed in the light emitting part is promoted to weaken the arc tube, causing leakage from the weakened part. The lamp life may be shortened.

These problems are particularly noticeable when a high-pressure metal vapor discharge lamp is lit by a mercury lamp ballast. For example, in the case of a medium-watt (200 W to 400 W) class high-pressure metal vapor discharge lamp, the lamp is lit with a dedicated ballast. The set lamp voltage when turning on is approximately 90V to 100V, whereas the set lamp voltage when turning on with a mercury lamp ballast is approximately 130V. Occurs earlier than when.

Recently, in order to obtain high lamp efficiency, cerium halide (CeI ₃ ) and sodium halide (NaI) are selected as the luminescent materials to be enclosed in the light emitting part of the ceramic arc tube, and the molar composition ratio thereof. A high-pressure metal vapor discharge lamp in which NaI / CeI ₃ is selected in the range of 3.8 to 10 has been proposed (see Patent Document 1).
JP 2003-86130 A

However, when cerium halide is encapsulated to increase the lamp efficiency to 100 (lm / W) or more, the green spectral emission of cerium halide having high specific sensitivity increases, and the light source color is greener than white. Therefore, there is a problem in that the color rendering performance is lowered, the average color rendering index (Ra) is less than 80, and the lamp voltage is rapidly increased as the lighting time elapses to cause the lamp to go out. This increase in lamp voltage is due to the inclusion of cerium halides compared to the cases where dysprosium halides, holmium halides, thallium halides, sodium halides, etc., which are conventionally known luminescent materials, are enclosed. In this case, the lamp voltage is much more rapid and the degree of increase in the lamp voltage is larger. Moreover, even if the lamp voltage increases with the dedicated ballast, the lamp voltage rises as much as with the mercury lamp ballast.

The present invention has a technical object to provide a high-efficiency, high color rendering, and long-life high-pressure metal vapor discharge lamp. In particular, the present invention relates to a high-pressure metal vapor discharge lamp using a ceramic arc tube. W) Higher efficiency than the above, and high color rendering of an average color rendering index (Ra) of 80 or more belonging to the color rendering property group 1B recommended by the International Lighting Commission (CIE) as office lighting, etc., and the light source color is white The problem is to prevent the lamp from going out even if it is lit with a ballast for mercury lamps.

In order to solve the above-mentioned problems, the present invention provides a high-pressure metal vapor discharge lamp in which a light emitting portion of an arc tube having electrodes provided at both ends is formed of a light-transmitting ceramic material. cerium halides, sodium halides and calcium halides are sealed, said with sodium halide and cerium halide molar ratio NaI / CeI ₃ of is selected in the range of 8 to 95, wherein the calcium halide and cerium halide molar ratio _CaI 2 / CeI ₃ of products is characterized in that it is selected in the range of 5-60.

According to the present invention, a cerium halide, a sodium halide, and a calcium halide are encapsulated as a luminescent material in a light emitting portion of a light emitting tube that is formed of a translucent ceramic material and has a large wall load. And the cerium halide molar composition ratio NaI / CeI ₃ within the above range, and the calcium halide and cerium halide molar composition ratio CaI ₂ / CeI ₃ within the above range, the lamp efficiency 100 (lm / W) high efficiency and high color rendering with an average color rendering index (Ra) of 80 or more, and the light source color is white (warm white as specified in JIS as the light source color of the fluorescent lamp, White and day white) and when lighting with mercury ballasts as well as with special ballasts There is also an effect that a high-pressure metal vapor discharge lamp that does not disappear can be obtained.

The best embodiment of the high-pressure metal vapor discharge lamp according to the present invention is a tube wall load 19-30 (W / cm) in which a light-emitting tube provided with electrodes on both ends is formed with a light-emitting portion of a translucent ceramic material. ² ) a ceramic arc tube, and in the light emitting portion thereof, a rare earth element halide containing at least cerium halide, a sodium halide, and a calcium halide are encapsulated as a luminescent material, and further sodium halide. And the cerium halide molar composition ratio NaI / CeI ₃ is selected in the range of 8 to 95, and the calcium halide and cerium halide molar composition ratio CaI ₂ / CeI ₃ is selected in the range of 5 to 60. Yes.

FIG. 1 is a cross-sectional view showing an example of an arc tube used in a high-pressure metal vapor discharge lamp according to the present invention. The arc tube 1 shown in FIG. 1 has a tube wall load 21 (W / cm ² ) used for a starter built-in type metal halide lamp (high-pressure metal vapor discharge lamp of this embodiment) having a rated lamp power of 360 W that can be lit by a mercury lamp ballast. ), The central light emitting portion 2 and the thin tube portions 3L and 3R provided at both ends thereof are formed of translucent polycrystalline alumina. The tube wall load here refers to the rated lamp power (W) / the total inner surface area (cm ² ) of the arc tube.

In the light emitting section 2, cerium halide, thulium halide, sodium halide, calcium halide, and thallium halide, which are halides of rare earth elements, are encapsulated as a light emitting substance, and as a discharge catalyst. Mercury and noble gases are enclosed. The thin tube portions 3L and 3R are inserted with electrode systems 4L and 4R each composed of an electrode 5 and a power feeder 6 for supplying lamp power to the electrodes, and the inside thereof is hermetically sealed.

Experimental data following Table 1, together made different variously sodium halide and cerium halide molar ratio NaI / CeI ₃ of encapsulated within the light emitting portion 2 of the arc tube 1 over a value range of 1 to 120, the light emitting portion A total of 16 types of lamps of the same type that are different from the above-mentioned metal halide lamps in that calcium halide is not sealed in 2 are experimental samples, and the lamp efficiency (lm / W) of each of the samples 1 to 16 The average color rendering index (Ra) is measured, and whether the light source color is within the range of warm white, white and daylight white of the light source color specified in JIS as the light source color of the fluorescent lamp. It shows the result of the evaluation.

According to this result, as the sample 1 and 2, when sodium halide and cerium halide molar ratio NaI / CeI ₃ of is in the range of 1-3, the green spectrum of high spectral luminous efficiency cerium halide Radiation increases, lamp efficiency reaches 119-120 (lm / W), and high efficiency of 100 (lm / W) or more can be achieved, while the light source color is tinged with green, JIS And the average color rendering index (Ra) is 77 to 78, and high color rendering of 80 or more cannot be achieved.

Also, as the samples 15 and 16, when sodium halide and cerium halide molar ratio NaI / CeI ₃ of is in the range of 110 to 120, the warm white color light source according to JIS-compliant, white and daylight white range The average color rendering index (Ra) is 86 to 87, and high color rendering of 80 or more can be achieved. However, the lamp efficiency is 97 to 99 (lm / W) and 100 (lm / W). The above high efficiency cannot be achieved.

On the other hand, when the molar composition ratio NaI / CeI ₃ is in the range of 5 to 100 as in Samples ₃ to 14, the lamp efficiency is 101 to 118 (lm / W), and the average color rendering index (Ra) is 80. The light source color is also in the range of warm white, white and daylight white in accordance with JIS. That is, if the molar composition ratio of cerium halide that produces green light emission and sodium halide that produces strong light emission from red to orange is selected appropriately, and the visible light is emitted in a well-balanced manner, the light source color can be changed. It is possible to achieve white color, and at the same time, it is possible to achieve a high color rendering efficiency of 100 (lm / W) or higher and a high color rendering index (Ra) of 80 or higher.

However, when a life test was performed in which each of the lamps of samples 3 to 14 in which the molar composition ratio NaI / CeI _{3 of} sodium halide to cerium halide was in the range of 5 to 100 was performed for a long time, There was something that caused the voltage to rise and disappear. As a cause of the increase in lamp voltage when the lamp is lit for a long time, the position of the coldest part of the arc tube 1 may be changed.

That is, the coldest part of the arc tube 1 is present in the narrow tube portions 3L and 3R. Therefore, when the lamp is lit for a long time, the ceramics of the thin tube portions 3L and 3R and the cerium halogen which is a rare earth element halide. The ceramics are eroded by reaction with the chemicals, and the eroded food accumulates in the thin tube portions 3L and 3R, so that the coldest portion is closer to the light emitting portion 2 than the initial position and the lamp voltage is increased. it is conceivable that. Actually, when the arc tube 1 of the lamp that disappeared during the rated life was analyzed, it was confirmed that ceramic erosion was accumulated in the thin tube portions 3L and 3R. The degree of increase in the lamp voltage was much more remarkable than that of the lamp using the arc tube in which the cerium halide was not enclosed.

Therefore, a light emitting substance calcium halide (CaI ₂ ) that additionally serves to suppress the reaction between the rare earth element halide and the ceramic is additionally enclosed in the light emitting portion 2 of the arc tube 1 used for the lamps of the samples 3 to 14. Then, when the life test of each of these lamps was performed, it was suppressed that the erosion of ceramics accumulated in the thin tube portions 3L and 3R and the position of the coldest portion of the arc tube 1 changed, but the sample 3 The lamp had a high probability of going out during the rated life, and the lamp of the sample 14 did not reach a lamp efficiency of 100 (lm / W).

Analysis of the cause, when sodium halide and cerium halide molar ratio NaI / CeI ₃ of less than 8, irrespective of the charging amount of calcium halide, resulting extinction early, its molar ratio When it was 8 or more, it was found that the lamp voltage did not disappear during the rated life. It was also found that if the molar composition ratio is 95 or less, a lamp efficiency of 100 (lm / W) or more can be achieved regardless of the amount of calcium halide enclosed.

Accordingly, the light emitting portion 2 of the arc tube 1 is filled with calcium halide that has a function of suppressing the reaction between the rare earth element halide and the ceramic and suppressing the position of the coldest portion of the arc tube 1 from changing, and if selected molar ratio NaI / CeI ₃ of sodium halide and cerium halide enclosed in its light-emitting portion 2 in the range of 8-95, lamp efficiency 100 (lm / W) or more and high efficiency, the average A high color rendering index (Ra) of 80 or more can be achieved, and at the same time, a long-life lamp can be obtained in which the lamp voltage does not go out even if the lamp is lit for a long time.

In addition, for each of the lamps of Samples 3 to 14, the molar composition ratio CaI ₂ / Ce ₃ of calcium halide and cerium halide was changed by changing only the amount of calcium halide enclosed without changing the amount of cerium halide enclosed. Many prototypes with various differences in the range of 1 to 100 were manufactured, and each lamp efficiency, color rendering property and light source color were evaluated. As the molar composition ratio CaI ₂ / CeI ₃ was smaller, the lamp efficiency was higher. However, the color rendering is reduced and the light source color is out of the white range.On the contrary, when the numerical value is increased, the color rendering is improved and the light source color is white, but it is confirmed that the lamp efficiency is lowered. At the same time, if the numerical value is selected within the range of 5 to 60, the lamp efficiency is 100 (lm / W) or higher, and the average color rendering index (Ra) is 80 or higher. Rukoto can, and light source color may become white was confirmed.

Furthermore, in the present embodiment, the tube wall load of the arc tube 1 is designed to be 21 (W / cm ² ), but the tube wall load of the arc tube 1 is varied for each lamp of the samples 3 to 14. A number of prototypes were made and the lamp efficiency, average color rendering index, light source color, and extinction due to a rise in lamp voltage were evaluated. If the tube wall load was smaller than 19 (W / cm ² ) The temperature of the arc tube 1 is lowered, the evaporation / light emission of the encapsulated material other than the cerium halide is insufficient, and the green spectrum radiation of the cerium halide is conspicuous, and the lamp efficiency is 100 (lm / W) or more. However, the average color rendering index (Ra) was lower than 80, and the light source color was also out of the range of warm white, white, and daylight white according to JIS. In addition, when the tube wall load of the arc tube 1 is greater than 30 (W / cm ² ), the temperature of the arc tube 1 is rapidly increased, so that the light emitting part 2 cannot withstand the thermal load, and the rated life is exceeded. Lamp failure occurs due to arc tube cracks and leaks much earlier.

On the other hand, when the tube wall load of the arc tube 1 is selected within the range of 19 to 30 (W / cm ² ), the average color rendering index (Ra) is 80 or more, and the light source color is within the JIS range. There are no lamp defects caused by arc tube cracks or leaks. Similar experimental results were obtained for 180 W and 220 W lamps that can be lit with mercury ballasts and 150 and 400 W lamps that can be lit with dedicated ballasts.

Therefore, in the high-pressure metal vapor discharge lamp of the present embodiment, the tube wall load of the arc tube 1 is selected in the range of 19 to 30 (W / cm ² ), and the light emitting portion 2 of the arc tube 1 is used as a luminescent substance. cerium halides, sodium halides and calcium halides are sealed, and with sodium halide and cerium halide molar composition NaI / CeI ₃ of is selected in the range of 8-95, the calcium halide and cerium halide The molar composition ratio CaI ₂ / CeI ₃ is selected in the range of 5 to 60, which enables high efficiency of lamp efficiency of 100 (lm / W) or more and high color rendering of average color rendering index (Ra) of 80 or more. At the same time, the whiteness of the light source color is high. It can be obtained lamp life that does not cause the lamp not point due to leakage.

In addition, although the light emission part 1 and the thin tube part 3L, 3R are each shape | molded separately by the arc tube 1 of a present Example, not only this but the light emission part and the thin tube part may be integrally molded. . Further, the shape of the light emitting part is not limited to the spindle shape as shown, but may be a cylindrical shape or an elliptical sphere shape. In this embodiment, thulium (Tm) halide is selected as the halide of rare earth elements other than cerium to be enclosed in the light emitting portion 2 of the arc tube 1, but instead of this, dysprosium ( A halide of Dy) or holmium (Ho) may be selected.

INDUSTRIAL APPLICABILITY The present invention can provide a high-efficiency, high color rendering, high whiteness, and long-life high-pressure metal vapor discharge lamp that is useful as indoor lighting in stores and outdoor lighting on streets.

Sectional drawing which shows an example of the arc tube used for the high pressure metal vapor discharge lamp which concerns on this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emission tube 2 Light emission part 3L Thin tube part 3R Thin tube part 4L Electrode system 4R Electrode system 5 Electrode 6 Feeding body

Claims (2)

In the high pressure metal vapor discharge lamp in which the light emitting part of the arc tube provided with electrodes at both ends is formed of a translucent ceramic material, cerium halide, sodium halide and calcium halide are used as the light emitting substance in the light emitting part. The molar composition ratio NaI / CeI _{3 of the} sodium halide and cerium halide is selected in the range of 8 to 95, and the molar composition ratio CaI ₂ / CeI _{3 of the} calcium halide and cerium halide is 5 A high pressure metal vapor discharge lamp characterized by being selected in a range of ˜60. High-pressure metal-vapor discharge lamp according to claim 1, wherein the tube wall loading of said arc tube is selected in the range of 19~30W / cm ^2.

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