JP3293499B2 - High pressure discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure discharge lamp having an arc tube made of ceramics.

[0002]

2. Description of the Related Art A high-pressure discharge lamp having an arc tube made of ceramics is compared with a high-pressure discharge lamp having an arc tube made of quartz which has been generally used so far. Since the reaction is small, it is expected that stable life characteristics can be obtained. Further, for the above-mentioned reason, by increasing the load on the arc tube compared to the arc tube made of quartz and raising the coldest point temperature of the arc tube, the vapor pressure of the discharge space of the encapsulated metal compound is increased, and high lamp efficiency ( l
m / W) and excellent color characteristics can be realized.

[0003] Conventional high pressure discharge lamps of this type include:
Translucent alumina tube whose tube end is closed with an insulating ceramic cap or a conductive cap
283543) and a conductive lead having an electrode is inserted into a cylindrical end provided on each side of the main tube of the arc tube, and a gap between the cylindrical end and the conductive lead is formed. A structure in which a ceramic sealing frit is used for sealing is known (JP-A-6-196131).

[0004]

A metal halide lamp having an arc tube made of ceramics has been put to practical use in an indoor commercial space and the like.
It achieves a life performance of 000 hours and a high efficiency of 90 lm / W. As for the color characteristics, it is assumed that an average color rendering index (Ra) of 83 and a special color rendering index (R9) of -28 have been realized for a bulb color at a low color temperature (3000 K). However, although this 3000K correlated color temperature is suitable as an alternative to a light bulb, it cannot be said that it is suitable for use in a commercial space centered on white, which is desired in Japan.

On the other hand, some conventional high pressure discharge lamps having an arc tube made of quartz have a correlated color temperature of 3500K to 5500K.
A compact metal halide lamp that emits white light of 000K and has a high color rendering performance of Ra95 or more has been put to practical use. As a filling material for such a lamp, a material obtained by adding thallium and cesium iodides to a rare earth metal iodide such as dysprosium is generally used. As described above, such a lamp has white light having high color rendering properties, but has a relatively low lamp efficiency of 75 lm / W because a continuous spectrum emitted by a rare earth metal is mainly used. Further, the rare earth metal easily reacts with quartz which is a material of the arc tube, and silicon is generated by this reaction. This silicon damages the electrode, scatters tungsten as an electrode material, and the tungsten adheres to the arc tube wall to darken the arc tube, causing a large decrease in luminous flux during the lifetime. Further, the blackening of the arc tube raises the temperature of the arc tube. As a result, the vapor pressure of the rare-earth metal iodide increases, so that the continuous spectrum on the long wavelength side increases.
As described above, there is a problem that the correlated color temperature is lowered.

In order to solve the above problems, an arc tube made of ceramics having low reactivity with an encapsulating metal is used in place of the conventional arc tube made of quartz, and an enclosure similar to the arc tube made of quartz is used. By enclosing, it is expected that a metal halide lamp that suppresses color temperature shift during the lifetime, increases efficiency, and has high color rendering white light can be realized.

However, dysprosium-thallium-cesium (65: 1) is used for the arc tube made of ceramics.
5:20 wt%), the vapor pressure of the rare earth metal iodide is increased as compared with that of a quartz arc tube, which leads to an increase in the continuous spectrum centered on the long wavelength side spectrum having low luminous efficiency. Results. Therefore, there is almost no increase in lamp efficiency.

[0008] Furthermore, due to an increase in the iodide vapor pressure, there arises a problem that the re-ignition portion of the lamp voltage at the time of sine wave lighting rises, and the lamp extinction voltage also rises.

Further, since the temperature of the arc tube is high and the vapor pressure of the rare earth metal iodide is higher than that of the arc tube made of quartz, the vapor pressure of the rare earth metal iodide due to a change in the coldest point temperature of the arc tube is increased. Changes have a significant effect on lamp characteristics.
Therefore, depending on the lighting direction of the lamp, a large change in color temperature and a change in lamp voltage occur. In particular, when the lighting direction is changed from vertical lighting to horizontal lighting, the lamp voltage greatly increases, and in some cases, the lamp goes out.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-pressure discharge lamp having high efficiency and high color rendering white radiation, stable life characteristics, little change in characteristics depending on the lighting direction, and less likely to extinguish. Is what you do.

[0011]

According to the present invention, there is provided a high-pressure discharge lamp comprising: a main tube having a pair of electrodes disposed therein;
Provided at both ends of the part, and inside the electrode at the tip
The introduction line having a thin tube portion sealed by a sealing material.
A light-emitting tube made translucent ceramics having the
A gap is formed between the inner wall of the thin tube portion and the introduction line.
At least a rare earth metal halide and a metal halide containing sodium halide are sealed inside the arc tube as an enclosure, and the weight ratio of the sodium halide to the rare earth metal halide is 10%. ~ 100% and correlated color temperature of 3500K
It is issued a release Shako of ~5000K.

As a result, it is possible to obtain a high-pressure discharge lamp that is highly efficient, has high color rendering white light that is stable throughout its life, has little variation in characteristics depending on the lighting direction, and does not easily extinguish.

[0013]

DETAILED DESCRIPTION OF THE INVENTION A high pressure discharge lamp according to claim 1 of the present invention comprises: a main tube in which a pair of electrodes are disposed;
The electrodes are provided at both ends of the main pipe portion and are internally provided.
The lead wire at the tip is thin with a sealing material
A light-emitting tube made translucent ceramics having a tubular portion, a gap forms between the inner wall and the lead-in wire of the narrow tube portion
At least a rare earth metal halide and a metal halide containing sodium halide are sealed inside the arc tube as an enclosure, and a weight ratio of the sodium halide to the rare earth metal halide is contained. Is 10% to 100%, and the correlated color temperature is 3%.
It is issued a release Shako of 500K~5000K.

By adding an appropriate amount of sodium halide, at a high operating temperature of the arc tube made of ceramics, it is possible to adjust the continuous spectrum of the rare earth metal having an appropriate intensity necessary for enhancing the color rendering and the color temperature. A spectrum of sodium that increases efficiency can be obtained,
Color temperature of 350 while maintaining high color rendering and lamp efficiency
A high-pressure discharge lamp with a clear white radiation of 0 to 5000 K can be realized.

It should be further noted that the action of sodium having a low excitation / ionization voltage suppresses a rise in the re-ignition portion of the lamp voltage even when the halide has a very high vapor pressure, thereby extinguishing the lamp. It has the effect of preventing the voltage from rising. Similarly, when the lighting direction is changed and the coldest point temperature further rises, the vapor pressure of the rare earth metal iodide rises, and at the same time, the vapor pressure of sodium iodide, which has a low ionization / excitation voltage, rises. Has the effect of suppressing the rise of the lamp and preventing the lamp from going out.

A high-pressure discharge lamp according to a second aspect of the present invention is the high-pressure discharge lamp according to the first aspect, having a configuration in which a metal halide contains cesium halide.

Thus, the addition of cesium having a low ionization voltage has the effect of improving the life characteristics. Originally, cesium has a lower ionization voltage than sodium. By adding cesium, the same effect as that obtained by adding sodium can be obtained. However, as in the conventional case, a large amount of cesium is used (20%). If added, there is a problem that the lamp efficiency is reduced. Furthermore, when cesium is actually used together with a rare earth metal, a composite halide of cesium and a rare earth metal is generated in the arc tube, and the vapor pressure of the halide containing the rare earth metal increases, so that when the operating temperature of the arc tube is high, It does not lead to the effect of reducing the re-ignition portion of the lamp voltage. Therefore, in this case, cesium is added in a relatively small amount to improve the life characteristics by lowering the arc temperature.

The high pressure discharge lamp according to claim 3 of the present invention is the high pressure discharge lamp according to claim 1 or 2, wherein the rare earth metal halide is dysprosium halide, thulium halide, or halogen. It has a structure containing at least one of holmium oxide.

[0019] Thus, these metals having a continuous spectrum in the visible region, while maintaining high efficiency,
It has the effect of improving color rendering.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. A 150 W high-pressure discharge lamp according to an embodiment of the present invention shown in FIG. 1 includes an arc tube 1 made of ceramics in an outer tube 2 sealed by a stem 3. It has a configuration fixed and supported by the extending metal wires 3a, 3b. A predetermined amount of mercury, argon as a starting rare gas are sealed in the arc tube 1, dysprosium as a rare earth metal emitting a continuous spectrum as metal halide, thallium for adjusting light color, and efficiency as a metal halide. A sodium iodide for encapsulating a high turning-off voltage and improving a lighting direction variation characteristic is sealed. The inside of the outer tube 2 is evacuated to a vacuum. Reference numeral 4 denotes a base.

The arc tube 1 made of ceramics shown in FIG. 2 has an outer diameter of 2.8 m at both ends of a main tube portion 6 having an outer diameter of 10 mm.
m, and narrow tube portions 7a and 7b each having an inner diameter of 1.0 mm are provided. Introductory wires 9a made of niobium having an outer diameter of 0.9 mm and having an electrode at the tip are provided in the thin tube portions 7a and 7b.
9b are inserted. The introduction wires 9a and 9b are inserted into the thin tube portions 7a and 7b so that the electrodes 5a and 5b are positioned in the main tube portion 6, and are sealed in the thin tube portions 7a and 7b by the sealing members 10a and 10b. , 8b.

Reference numeral 11 denotes mercury, and 12 denotes iodide pellets. Table 1 shows the high-pressure discharge lamp of the present embodiment (hereinafter, referred to as the present invention) in which iodide of dysprosium-sodium-thallium (55:30:15 wt%) was enclosed as the filling, and the present invention. The initial characteristics at the time of vertical lighting with a comparative lamp (hereinafter, referred to as a comparative product) having a similar structure and using an enclosure (dysprosium-thallium-cesium iodide) to which sodium is not added are shown.

Cesium in this case is added to stabilize arc discharge.

[0024]

[Table 1]

As described above, the product of the present invention in which dysprosium-sodium-thallium (55:30:15 wt%) is encapsulated has a high lamp efficiency of 96 lm / W and a white light having a color temperature of 4100K. The color rendering properties were as high as an average color rendering index of 95, showing very good lamp characteristics.

On the other hand, the comparative product to which sodium was not added had white radiation having high color rendering properties similar to the product of the present invention, but had a lamp efficiency of 85 lm / W. The superiority is small compared with the lamp efficiency of 75 lm / W of the used lamp. Further, the value of the extinguishing voltage is equivalent to that of the product of the present invention despite the low lamp voltage. That is, it can be said that the present invention product has a substantially lower extinction voltage.

Next, Table 2 shows the difference in various characteristics depending on the lighting direction of these lamps.

[0028]

[Table 2]

As is clear from Table 2, the lamp of the present invention has a lamp voltage difference of 6.1 V between vertical lighting and horizontal lighting, whereas the comparative product has a lamp voltage difference of 16 V between vertical lighting and horizontal lighting. .1 V, which is higher than that of the product of the present invention. Further, as for the extinguishing voltage, the product of the present invention only rises by 11 V from vertical lighting to horizontal lighting, while it rises by 35 V in the case of the comparative product.

As is evident from these results, the product of the present invention exhibits good color characteristics and is less likely to disappear as compared with a comparative product having the same characteristics. Further, it can be seen that the lamp is hardly extinguished even when an arbitrary lighting direction is freely selected, since the lamp voltage and the extinguishing voltage vary little depending on the lighting direction.

FIG. 3 shows the weight ratio of sodium iodide to dysprosium iodide (a = NaI) for the product of the present invention.
/ DyI ₃ ), a change in color temperature, a change in average color rendering index, and a change in extinguishing voltage when the lighting posture is changed from vertical to horizontal. In FIG.
The solid line represents the relationship between the weight ratio a and the color temperature, the dotted line represents the relationship between the weight ratio a and the variation in the lighting direction of the extinguishing voltage, and the dashed line represents the relationship between the weight ratio a and the average color rendering index. As shown here, when the weight ratio a exceeds 1.0 (100%), the color temperature becomes closer to the bulb color, and the average color rendering index is reduced to less than 90. Further, when the weight ratio a is 0.3 (30%) or less, the change of the extinguishing voltage when the lighting posture is changed from vertical to horizontal increases, and when the lighting ratio is 0.1 (10%) or less, it exceeds 20 V. If the change of the extinguishing voltage exceeds 20 V, it may cause extinguishing when the lamp voltage rises during the life of horizontal lighting.

FIG. 4 shows a comparative product in which dysprosium-thallium-cesium iodide is sealed in a quartz arc tube,
The color temperature change during the life of the product of the present invention in which dysprosium-thallium-sodium iodide is sealed in an arc tube made of ceramics is shown. As is clear from this figure, it was confirmed that the color temperature change during the life of the product of the present invention was significantly improved.

In this embodiment, dysprosium-sodium-thallium iodide is sealed, but dysprosium-thallium-sodium-cesium (53: 1) is used.
(5: 29: 3 wt%), a small amount of cesium may be added to improve the life characteristics due to a decrease in arc temperature caused by cesium having a low ionization voltage.

In this embodiment, a niobium wire is used as the lead wire for the sealing portion. However, other lead wire materials having a coefficient of thermal expansion close to that of the arc tube material may be used instead of niobium wire. In addition, a conductive or non-conductive ceramic cap may be used for the sealing portion. Also, the shape of the arc tube does not have to include the thin tube portion.

Regarding the filling material, bromide, iodide,
A halide such as chloride may be used, or a mixture thereof may be used. As for the rare earth metal, a rare earth metal iodide other than dysprosium such as thulium or holmium, which can further enhance the effect, or a mixture thereof may be used.

[0036]

As described above, according to the present invention,
An object of the present invention is to provide a high-pressure discharge lamp having high efficiency and high color rendering white light, stable life characteristics, little change in characteristics depending on the lighting direction, and hard to extinguish.

[Brief description of the drawings]

FIG. 1 is a front view of a high-pressure discharge lamp according to an embodiment of the present invention.

FIG. 2 is a sectional front view of the arc tube.

FIG. 3 is a diagram showing a relationship between a ratio of sodium iodide to a rare earth metal iodide, a color temperature, an average color rendering index, and a change in a turn-off voltage depending on a lighting direction.

FIG. 4 is a diagram showing a change in color temperature during the life of the product of the present invention and a comparative product.

[Explanation of symbols]

 Reference Signs List 1 arc tube 2 outer tube 3 stem 3a, 3b metal wire 4 base 5a, 5b electrode 6 main tube 7a, 7b narrow tube 8a, 8b sealing 9a, 9b introduction line 10a, 10b sealing material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-230946 (JP, A) JP-A-64-19671 (JP, A) JP-A-10-50264 (JP, A) JP-A-9-96 270246 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 61/20

Claims (3)

(57) [Claims] 1. A main pipe portion in which a pair of electrodes are disposed.
And provided at both ends of the main pipe part,
Lead wire with a pole at the tip is sealed with a sealant
It provided with a light-emitting tube made translucent ceramics having a narrow tube portion, a gap between the lead-in wire and the inner wall of the narrow tube portion
Is formed, and at least a rare earth metal halide and a metal halide containing sodium halide are sealed inside the arc tube as an enclosure, and the weight of the sodium halide with respect to the rare earth metal halide is sealed. the ratio is 10% to 100%, the high-pressure discharge lamp which correlated color temperature is characterized in that calling the release Shako of 3500K～5000K. 2. The high-pressure discharge lamp according to claim 1, wherein the metal halide includes cesium halide. 3. The method according to claim 1, wherein the rare earth metal halide includes dysprosium halide, thulium halide, and
3. The high-pressure discharge lamp according to claim 1, comprising at least one of holmium halide.