JPH07335180A - Mercury vapor discharge lamp and illumination device incorporating it - Google Patents

Abstract

PURPOSE:To provide a mercury vapor discharge lamp and an illumination device, with which deterioration of a fluorescent lamp upon reception of 185-nm ultraviolet rays is suppressed and also an enhanced light emission efficiency and rate of light flux maintenance are presented. CONSTITUTION:A mercury vapor discharge lamp has a bulb 1 in which mercury and a rare gas are encapsulated, and a phosphor film 2 is formed on the inner surface of this bulb 1, wherein the phosphor film 2 consists of two layers, of which the phosphor layer 21 on the bulb wall side is formed from a phosphor, which emits light upon absorbing 254-nm ultraviolet rays, while the phosphor layer 22 on the discharge space side is formed from a phosphor which absorbs 185-nm when receiving 185-nm ultraviolet rays and emits light of longer wavelength than the absorbed. Thus the phosphor layer on the discharge space side absorbs 185-nm ultraviolet rays and emits light of longer wavelength, so that the phosphor layer on the bulb wall side is prevented from receiving 185-nm ultraviolet rays to ensure that the visible ray converting function of the phosphor layer on the bulb wall side is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mercury vapor discharge lamp such as a high load fluorescent lamp and an illuminating device using this discharge lamp.

[0002]

2. Description of the Related Art Low-pressure mercury vapor discharge lamps, such as fluorescent lamps, have been used in a wide range of fields such as general lighting, light sources for OA equipment, pixel light sources for huge screens, backlights for liquid crystal displays, etc. .

In such a fluorescent lamp, a phosphor coating is formed on the inside of an arc tube bulb made of a transparent glass tube, and a mixed gas containing mercury and one or more rare gases is provided in the bulb. Is enclosed. When a positive column discharge is generated between the electrodes provided at both ends of the bulb,
The mercury enclosed in the arc tube is evaporated, the mercury atoms are excited and ionized, and when the mercury atoms are excited, the ultraviolet rays of 185 nm and 254 nm, which are mercury resonance lines, are emitted. These ultraviolet rays are converted into visible light by a phosphor formed on the inner surface of the tube wall, and this visible light is emitted to the outside of the arc tube.

[0004]

However, such a fluorescent lamp has a problem that the luminous flux decreases as the lighting time elapses. Especially in the case of a high-load fluorescent lamp, the luminous flux is significantly reduced. The following reason is considered as a cause of the decrease in luminous flux in the case of a high-load fluorescent lamp. That is, in this type of fluorescent lamp, it is considered that the fluorescent material coated on the inner surface of the bulb is deteriorated and deteriorated by receiving ultraviolet rays having a wavelength of 185 nm which is a resonance line of mercury.

Usually, most of ultraviolet rays emitted from mercury are ultraviolet rays of 254 nm, and ultraviolet rays of 185 nm occupy only about 10 to 12% of all ultraviolet rays. However, it is said that the 185 nm ultraviolet ray has a property of deteriorating the phosphor.

In the case of a low-load fluorescent lamp, ultraviolet rays of 185 nm emitted from mercury occupy only about 12% of the total ultraviolet rays as described above. The intensity ratio of 185 nm becomes large, and thus the deterioration of the phosphor due to ultraviolet rays becomes severe.

In recent fluorescent lamps, the shape of the glass tube is not limited to the straight tube type, but it is formed into a ring shape, a U shape, a saddle shape or the like, and the size and size of the fluorescent lamp are rapidly increasing. Miniaturization of such a fluorescent lamp tends to increase the tube wall load, and therefore, as the tube wall load increases,
As described above, the intensity ratio of 185 nm to 254 nm becomes large, so that the deterioration of the phosphor becomes severe.

As a result, a lamp having a high tube wall load has a larger luminous flux lowering rate than an ordinary lamp, and further, a coloring (blackening) phenomenon is likely to occur early.

[0009] As one means for preventing the deterioration of the phosphor due to the 185 nm ultraviolet ray, the phosphor particles are made of metal oxide,
For example, it has been proposed to cover with a protective film of magnesium oxide MgO. MgO has a property of absorbing 185 nm ultraviolet rays with almost no absorption of 254 nm ultraviolet rays. Therefore, if the phosphor particles are covered with such MgO protective film, 185 nm ultraviolet rays are cut and only 254 nm ultraviolet rays are fluorescent. It has been confirmed that it can reach the body, and even a high-load fluorescent lamp can prevent the deterioration of the fluorescent substance due to the ultraviolet rays of 185 nm.

However, the protective film of MgO has a disadvantage that the strength against ultraviolet rays is not so high, and such oxides have a property that the protective film itself is deteriorated by receiving 185 nm ultraviolet rays depending on the production thereof. The function of protecting the phosphor for a long period of time may be deteriorated, so that the effect of increasing the luminous flux maintenance factor of the lamp may not be expected.

Moreover, when the above MgO protective film is used,
MgO has a property of absorbing 185 nm ultraviolet light, and in fact, a part of the ultraviolet light emitted from mercury is absorbed by the MgO protective film and disappears, so that there is also a problem that the luminous efficiency decreases.

The present invention has been made in order to solve such a problem, and its object is to set a wavelength of 18
The deterioration of the phosphor due to the 5nm UV is suppressed, and the 185nm UV can be converted into light with a longer wavelength and can be effectively used for light emission, improving both the luminous efficiency and the luminous flux maintenance factor. It is intended to provide a mercury vapor discharge lamp and a lighting device using the same.

[0013]

According to a first aspect of the present invention, a translucent bulb in which mercury and a rare gas are enclosed, a phosphor coating provided inside the bulb, and a discharge in the bulb. In the mercury vapor discharge lamp, which is provided with a means for generating and maintaining this discharge, the phosphor coating comprises two or more layers, and the phosphor layer on the bulb wall side comprises:
It is mainly made of a phosphor that absorbs and emits 254 nm ultraviolet light, and the phosphor layer on the discharge space side is mainly made of a phosphor that absorbs 185 nm ultraviolet light and emits light of a wavelength longer than 185 nm. It is characterized by

Here, the phosphor coating may have two or more layers as a whole. For example, in the case of three layers, the phosphor layer on the bulb wall side is two layers and the phosphor on the discharge space side is one layer. ,
As a result, the total number of layers may be three.

Also, Al ₂ O ₃ and Zn are formed on the inner surface of the valve.
There may or may not be a protective film such as O or TiO ₂ . In the invention of claim 2, the phosphor layer on the discharge space side is 2
It is characterized in that it is formed of a phosphor that absorbs ultraviolet rays of 185 nm better than 54 nm.

According to a third aspect of the invention, the phosphor layer on the discharge space side is made of BaAl ₁₂ O ₁₄ : Mn, Y ₂ SiO ₅ : Ce, Y ₃
It is characterized in that it is formed of a single substance or a mixture of the phosphors of Al ₅ O ₁₂ : Ce and Y ₃ Al ₅ O ₁₂ : Tb.

The invention of claim 4 is characterized in that the rated tube wall load of the valve is 0.05 W / cm ² or more. According to a fifth aspect of the present invention, the mercury vapor discharge lamp according to any one of the first to fourth aspects, a lighting fixture body to which the discharge lamp is attached, and the mercury vapor discharge lamp provided in the fixture body. And a power supply circuit that is electrically connected between the power supply and a power source to maintain the lighting of the discharge lamp.

[0018]

According to the invention of claim 1, the fluorescent layer (second fluorescent layer) on the discharge space side absorbs 185 nm when it receives ultraviolet rays of 185 nm and emits light of a longer wavelength than this. Since it is formed of a body, the fluorescent material layer on the bulb wall side (first fluorescent material layer) is prevented from receiving ultraviolet rays of 185 nm, and therefore the fluorescent material layer on the bulb wall side contributing to the emission of visible light is It is prevented from being deteriorated by ultraviolet rays. In addition, the phosphor layer on the discharge space side emits light having a wavelength longer than 185 nm when it receives ultraviolet light of 185 nm, so that the deterioration of its own ultraviolet light is small, and therefore the luminous efficiency and the luminous flux maintenance rate are improved.

Further, according to the second aspect of the invention, since the phosphor layer on the discharge space side absorbs 185 nm and has a small absorption at 254 nm, the phosphor layer on the bulb wall side promotes the visible light converting action. be able to. Therefore, the luminous efficiency and the luminous flux maintenance factor are improved.

According to the invention of claim 3, the phosphor layer on the discharge space side is made of BaAl ₁₂ O ₁₄ : Mn, Y ₂ SiO ₅ : C.
e, Y ₃ Al ₅ O ₁₂ : Ce and Y ₃ Al ₅ O ₁₂ : Tb
Since it is formed of a single substance or a mixture of the above phosphors, it absorbs 185 nm when it receives an ultraviolet ray of 185 nm and emits light of a longer wavelength than that of 254 nm.
Since the absorption of ultraviolet rays of nm is small, the luminous efficiency and the luminous flux maintenance rate are improved.

According to the fourth aspect of the present invention, it is possible to favorably suppress the deterioration of the phosphor, although the lamp is applied to a high load lamp having a tube wall load of 0.05 W / cm ² or more. . According to the invention of claim 5, a lamp having excellent luminous efficiency and life characteristics is used as a light source, so that the characteristics of the lighting device are improved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 shows a straight tube fluorescent lamp, and reference numeral 1 is a transparent arc tube bulb made of soda lime glass. A phosphor coating 2 is formed on the inner surface of the bulb 1. This phosphor coating 2 is formed to have a laminated structure of two or more layers, in this example, two layers 21 and 22.

Phosphor layer on the bulb wall side (first phosphor layer)
21 is mainly light having a wavelength longer than 185 nm, or 2
A phosphor that emits visible light upon receiving an ultraviolet ray of 54 nm, for example, an antimony-manganese-activated halophosphate phosphor (Ca ₅
(PO ₄ ) ₃ (F, Cl): Sb, Mn) or a three-wavelength light emitting phosphor. Above Ca ₅ (PO
₄ ) ₃ (F, Cl): 25 in the case of Sb, Mn phosphor
When it receives an ultraviolet ray of 4 nm, it has a strong emission region for visible light such as 480 nm and 580 nm. The thickness t1 of the first phosphor layer 21 may be about 30 to 50 .mu.m, which is the same as the conventional one and is sufficient to emit visible light.

Phosphor layer on the discharge space side (second phosphor layer)
22 is 185 nm when it receives 185 nm ultraviolet light
Which absorbs the ultraviolet rays of the above and converts it into light having a wavelength longer than 185 nm, for example, manganese-activated aluminate phosphor (Ba
Al ₁₂ O ₁₄ : Mn). BaA above
The l ₁₂ O ₁₄ : Mn phosphor has a property of emitting light of 480 nm when it receives an ultraviolet ray of 185 nm. The thickness t2 of the second phosphor layer 22 is preferably about 5 to 20 .mu.m.

The ends of the valve 1 are closed by stems 3 and 3 and wells 4 ... Are pierced through the stems 3 and 3 in an airtight manner. Electrodes 5 and 5 in each wells 4 ...
Are attached, and these electrodes 5 and 5 are formed by a coil made of a tungsten filament. These electrodes 5 and 5 are coated with an electron emitting substance (emitter) made of BaO, SrO, CaO or the like, which is not shown.

Bases 6, 6 are attached to the ends of the valve 1, and base pins 7 projecting from the bases 6, 6 are provided.
Are electrically connected to the wells 4 described above. The arc tube 1 is filled with a predetermined amount of mercury and a rare gas such as argon having a predetermined pressure.

The operation of the fluorescent lamp having such a structure will be described. The fluorescent lamp of the above-mentioned embodiment has one of the mercury resonance lines from the mercury atoms ionized and excited by the discharge.
Although 85 nm and 254 nm ultraviolet rays are emitted, the phosphor coating 2 has a two-layer structure, and when the second phosphor layer 22 on the discharge space side receives 185 nm ultraviolet rays, 185 nm is emitted.
Since it is formed of a phosphor that converts light having a wavelength longer than nm, for example, a manganese-activated aluminate phosphor (BaAl ₁₂ O ₁₄ : Mn), ultraviolet light of 185 nm is emitted by the second phosphor layer 22 to 185 nm. It is converted to longer wavelength UV or visible light. Therefore, ultraviolet rays do not reach 185 nm in the first phosphor layer 21 on the bulb wall side,
Alternatively, the amount of light reaching the first phosphor layer 21 decreases and the first phosphor layer 21 becomes 1
It is prevented from being deteriorated or deteriorated by 85 nm UV light.

Of course, the second phosphor layer 2 on the discharge space side
Since No. 2 converts ultraviolet rays of 185 nm when it receives them, the second phosphor itself does not deteriorate or deteriorate due to the ultraviolet rays.

The second phosphor layer 22 on the discharge space side is also provided.
Absorbs a small amount of 254 nm ultraviolet light, so that a large amount of 254 nm ultraviolet light reaches the first phosphor layer 21. 185 nm converted by the second phosphor layer 22
Longer wavelength light (ultraviolet and / or visible light),
The 254 nm ultraviolet light transmitted through the second phosphor layer 22 reaches the first phosphor layer 21 and is converted into visible light by the first phosphor layer 21.

Therefore, the 185 nm ultraviolet rays are the second and first rays.
Since the phosphor layers 22, 21 are converted into visible light and emitted to the outside, the 185 nm ultraviolet ray can be effectively used for visible light. Therefore, the luminous efficiency is improved as compared with the case where the ultraviolet rays are simply absorbed at 185 nm.

In particular, as the lamp wall load increases, the increase rate of the 185 nm UV intensity exceeds the 245 nm UV intensity increase rate, and the 185 nm UV intensity ratio increases to the 245 nm UV intensity. Deterioration becomes severe.

For example, a general FL40W fluorescent lamp has a rated input of 40 W, an arc tube inner diameter of 37 mm, and an overall length of 1 mm.
It is 200 mm and the tube wall load is 0.029 W / cm ² . In this case, the intensity ratio of the 185 nm ultraviolet ray to the 245 nm ultraviolet ray is 0.12. On the other hand, in the case of the high output fluorescent lamp FLR60H • DA, the rated input is 60 W, the inner diameter of the arc tube is 37 mm, the total length is 1200 mm, and the tube wall load is 0.043 W / cm ² . In this case, the intensity ratio of the 185 nm ultraviolet ray to the 245 nm ultraviolet ray is about 0.2.

Even in such a high load fluorescent lamp,
The phosphor coating 2 has a two-layer structure as described above, the first phosphor layer 21 is formed of a phosphor that emits light upon receiving ultraviolet rays of 254 nm, and the second phosphor layer 22 is exposed to ultraviolet rays of 185 nm. If the second phosphor layer 22 receives a 185 nm ultraviolet ray and emits a long wavelength light, if it is formed by a phosphor that converts the light having a wavelength longer than 185 nm when received and has a small absorption of the 254 nm ultraviolet ray, The 185 nm ultraviolet light can be effectively used, and such light is converted into visible light by the first phosphor layer 21, so that the luminous efficiency is improved. Then, the first phosphor layer 21 has 18
Since the 5 nm ultraviolet ray does not reach or the amount of the ultraviolet ray does not reach, the deterioration and deterioration of the phosphor can be prevented, and the luminous flux maintenance factor is improved.

With respect to such a fluorescent lamp, it was investigated how the luminous efficiency and the luminous flux maintenance rate change with the passage of lighting time. The results are shown in Table 1 and the characteristic diagram of FIG. Table 1 below shows that the phosphor coating 2 is antimony.
Manganese-activated halophosphate phosphor (Ca ₅ (PO ₄ ) ₃
When it is formed as a single layer of (F, Cl): Sb, Mn (Sample a) (film thickness t = 40 μm), the first phosphor layer 21 and the second phosphor layer 22 of the example are formed. Two-layer structure (sample b)
These are the measured values of the results of examining the luminous flux lm at the lighting times of 0 and 1000 hours for (thickness t1 = 40 μm, t2 = 10 μm).

[0035]

[Table 1]

From Table 1, as in the embodiment of the present invention,
The phosphor coating is applied to the first phosphor layer 21 and the second phosphor layer 22.
It is confirmed that when the two-layer structure is used, the luminous flux is improved and the luminous efficiency is improved as compared with the other structure. This means that the second phosphor layer 22 receives ultraviolet rays of 185 nm and emits light having a long wavelength, and this long wavelength light is converted into visible light directly or by the first phosphor layer 21. It can be considered that the luminous efficiency is improved because it is emitted to the outside.

FIG. 2 shows the measured luminous flux maintenance factor. When the phosphor coating has a two-layer structure of the first phosphor layer 21 and the second phosphor layer 22 (Sample b), It is confirmed that the luminous flux maintenance factor is improved as compared with the other sample (Sample a). This is because the ultraviolet rays of 185 nm are blocked from reaching the first phosphor layer 21.
It is considered that the ultraviolet deterioration of the above was reduced.

FIG. 3 shows an example of a lighting device in which the fluorescent lamp of FIG. 1 is attached to a lighting fixture. That is, in the drawing, 30 is a main body of a ceiling-mounted lighting fixture, and lamp sockets 31,
31 are arranged to face each other. The fluorescent lamp shown in FIG. 1 is mounted between the sockets 31, 31 by engaging the base pins 7 of the bases 6, 6. A ballast 32 is housed in the fixture body 30 as a lighting circuit component for maintaining stable lighting of the lamp.
The fluorescent lamp is connected to a power source (not shown) via the ballast 32.

According to such an illuminating device, since the fluorescent lamp having excellent luminous efficiency is lit for a long period of time in an excellent luminous flux maintenance ratio, an illuminating device having high brightness and excellent life characteristics is provided. be able to.

The present invention is not limited to the structure of the above embodiment. That is, as the phosphor constituting the first phosphor layer 21, the antimony / manganese activated halophosphate phosphor (Ca ₅ (PO ₄ ) ₃ (F, C
l): Not limited to Sb, Mn) and three-wavelength emission type phosphors,
It is possible to use all the phosphors that have already been put to practical use in fluorescent lamps and high-pressure mercury lamps.

The first phosphor layer 21 may itself have a structure of two or more layers. In other words, 3 on the valve wall side
In addition to providing a phosphor layer made of a wavelength emission type phosphor,
The structure may be such that a phosphor layer made of an antimony / manganese activated halophosphate phosphor is provided inside this.

As the second phosphor layer 22 on the discharge space side, the manganese-activated aluminate phosphor (B
aAl ₁₂ O ₁₄ : Mn), cerium activated yttrim silica phosphor (Y ₂ SiO ₅ : Ce), cerium activated yttrim alumina phosphor (Y ₃ Al ₅ O ₁₂ : Ce), tribium activated Yttrim alumina phosphor (Y ₃ Al ₅ O
₁₂ : Tb) or the like or a mixture thereof may be used, and each of these phosphors emits light having a wavelength longer than 185 nm without deterioration when it receives an ultraviolet ray of 185 nm and has a wavelength of 254 nm. It has a property of low absorption.

The above BaAl ₁₂ O ₁₄ : Mn, Y ₂ SiO
FIG. 4 shows a characteristic diagram of the excitation wavelength of the phosphor composed of ₅ : Ce and Y ₃ Al ₅ O ₁₂ : Ce. From FIG. 4, the phosphors composed of BaAl ₁₂ O ₁₄ : Mn, Y ₂ SiO ₅ : Ce and Y ₃ Al ₅ O ₁₂ : Ce are all 18
It can be seen that the excitation wavelength is in the ultraviolet wavelength region around 5 nm, and therefore the property of absorbing ultraviolet light around 185 nm is strong.

Further, in the present invention, the shape of the fluorescent lamp is not limited to the straight tube shape, and it may be a ring-shaped fluorescent lamp or a compact fluorescent lamp formed in a U shape or an H shape. Further, it means that the phosphor coating provided inside the bulb is formed directly or indirectly on the inner wall surface of the bulb. That is, between the wall of the translucent bulb and the phosphor coating, for example, a transparent conductive coating provided in a rapid start type fluorescent lamp may or may not be interposed, and either of them may be used. On the inner surface of the valve 1 is Al ₂ O ₃ , Z for preventing deterioration of the valve.
There may or may not be a protective film made of nO, TiO _2, or the like.

The means for maintaining the discharge is composed mainly of, for example, electrodes, but is not limited to this, and in the case of a lamp called an electrodeless discharge lamp, for example, a transparent airtight seal is used. An induction coil provided on the outside of the container,
The external electrode corresponds to this.

The illuminating device may be a so-called light bulb type fluorescent lamp, a document illuminating device such as a copying machine, in addition to the luminaire. Further, the fluorescent lamp of the present invention may be used not only as a fluorescent lamp that emits visible light but also as an ultraviolet-emitting fluorescent lamp for a chemical reaction that emits an ultraviolet ray of 365 nm or the like.

[0047]

As described above, according to the first aspect of the present invention, the fluorescent layer on the discharge space side absorbs 185 nm when it receives ultraviolet rays of 185 nm and emits light of a longer wavelength than this. Since it is formed of a body, it prevents the fluorescent layer on the bulb wall side from receiving 185 nm ultraviolet light, and thus prevents the fluorescent layer on the bulb wall side contributing to the emission of visible light from being deteriorated by ultraviolet light. To be done. In addition, the phosphor layer on the discharge space side emits light having a wavelength longer than 185 nm when it receives ultraviolet light of 185 nm, so that the deterioration of its own ultraviolet light is small, and therefore the luminous efficiency and the luminous flux maintenance rate are improved.

According to the second aspect of the invention, since the phosphor layer on the discharge space side absorbs 185 nm but little absorption at 254 nm, the visible light converting action of the phosphor layer on the bulb wall side is promoted. You can Therefore, the luminous efficiency and the luminous flux maintenance factor are improved.

Further, according to the invention of claim 3, the phosphor layer on the discharge space side is made of BaAl ₁₂ O ₁₄ : Mn, Y ₂ SiO.
_{5: Ce, Y 3 Al 5} O 12: Ce and Y ₃ Al ₅
Since it is formed of a single substance or a mixture of O ₁₂ : Tb phosphors, it is 1 when it receives an ultraviolet ray of 185 nm.
It absorbs 85 nm and emits light of a longer wavelength than this, and it also absorbs less ultraviolet rays of 254 nm, improving the luminous efficiency and the luminous flux maintenance factor.

According to the invention of claim 4, the deterioration of the phosphor can be suppressed well, although the lamp is applied to a high load lamp having a tube wall load of 0.05 W / cm ² or more. . According to the invention of claim 5, a lamp having excellent luminous efficiency and life characteristics is used as a light source, so that the characteristics of the lighting device are improved.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 (A) is a side view of a fluorescent lamp, and FIG. 1 (B) is a cross-sectional view showing an enlarged structure of a phosphor coating in a portion B of FIG.

FIG. 2 is a characteristic diagram showing a luminous flux maintenance factor.

FIG. 3 is a side view of an illumination device using the fluorescent lamp of FIG. 1 as a light source.

FIG. 4 is a characteristic diagram showing the excitation wavelength of each phosphor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Arc tube 2 ... Phosphor coating 3 ... Stem 5 ... Electrode 21 ... Bulb-side first phosphor layer 22 ... Discharge space-side second phosphor layer 30 ... Lighting fixture main body 31 ... Lamp socket 32 ... stabilizer

Claims (5)

[Claims] 1. A translucent bulb filled with mercury and a rare gas, a phosphor coating provided inside the bulb, and means for generating and maintaining discharge in the bulb. In the mercury vapor discharge lamp comprising :, the phosphor coating is composed of two or more layers, and the phosphor layer on the bulb wall side is mainly formed of a phosphor that absorbs and emits 254 nm ultraviolet light, The mercury vapor discharge lamp is characterized in that the phosphor layer on the discharge space side is formed of a phosphor that mainly absorbs ultraviolet rays of 185 nm and emits light of a wavelength longer than 185 nm. 2. The phosphor layer on the discharge space side is 254 nm
The mercury vapor discharge lamp according to claim 1, wherein the mercury vapor discharge lamp is formed of a phosphor that absorbs ultraviolet rays of 185 nm better than the above. 3. The phosphor layer on the discharge space side is made of BaAl.
₁₂ O ₁₄ : Mn, Y ₂ SiO ₅ : Ce, Y ₃ Al ₅ O ₁₂ :
The mercury vapor discharge lamp according to claim 1 or claim 2, which is formed of a single substance or a mixture of Ce and Y ₃ Al ₅ O ₁₂ : Tb phosphors. 4. The rated tube wall load of the valve is 0.05 W / cm.
^{It is 2} or more, Claim 1 thru | or Claim 3 characterized by the above-mentioned.
The mercury vapor discharge lamp according to any one of 1. 5. The mercury vapor discharge lamp according to any one of claims 1 to 4, a lighting fixture body to which the discharge lamp is attached, the mercury vapor discharge lamp and a power source provided in the fixture body. And a lighting circuit part electrically connected between the lighting circuit part and the lighting circuit part for maintaining the lighting of the discharge lamp.