JPH0864173A - Mercury vapor discharge lamp and lighting system using this lamp - Google Patents

Abstract

PURPOSE: To provide a mercury vapor discharge lamp and a lighting system using this lamp, which suppresses deterioration of a fluorescent material caused by receiving a 185nm ultraviolet ray and enhances a luminous flux maintenance factor. CONSTITUTION: In a mercury vapor discharge lamp in which a fluorescent material film 2 is formed on the inside of a bulb 1, the fluorescent material film is formed with a fluorescent material which emits light by absorbing mainly a 254nm ultraviolet ray, and a protection layer 10 made of a composite metal oxide which absorbs a l85nm ultraviolet ray but transmits a 254nm ultraviolet ray, and does not emit light even if it absorbs the 185nm ultraviolet ray is formed on a discharge space side of the fluorescent material film. Since the protection layer 10 absorbs the 185nm ultraviolet ray to prevent the transmission of it, deterioration of the fluorescent material layer caused by receiving the 185nm ultraviolet ray is prevented. Since the protection layer 10 has no self deterioration by the 185nm ultraviolet ray and protects the fluorescent layer from the 185nm ultraviolet ray, a luminous maintenance factor is enhanced for a long time.

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. Particularly 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, but in a high-load fluorescent lamp with a high input power, it is 254 nm. To 185nm
The intensity ratio of the phosphor 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 absorbs 185 nm ultraviolet light, 25
Since it has a property of transmitting 4 nm ultraviolet light with almost no absorption, therefore, if the phosphor particles are covered with such a MgO protective film, the 185 nm ultraviolet light will be blocked and 254 nm will be cut off.
Only the ultraviolet rays of will reach the phosphor. therefore,
It has been confirmed that even a high-load fluorescent lamp can prevent the deterioration of the fluorescent substance due to 185 nm ultraviolet light.

However, the protective film made of MgO is
The protective film itself has a problem that the strength against ultraviolet rays is not so high, and such an oxide has a property that the MgO protective film itself is deteriorated by receiving 185 nm ultraviolet light depending on its production. If it progresses, the function of protecting the phosphor for a long period of time deteriorates, so that there is a problem that the effect of increasing the luminous flux maintenance factor of the lamp cannot be expected.

The present invention has been made in order to solve such a problem, and its object is to set a wavelength of 18
Deterioration of phosphor deterioration due to 5 nm UV rays is suppressed,
An object of the present invention is to provide a mercury vapor discharge lamp having an improved luminous flux maintenance factor and an illumination device using the same.

[0012]

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 is mainly formed of a phosphor that absorbs ultraviolet light of 254 nm and emits light. Absorbs 185nm UV and has 254nm
Is characterized in that a protective layer formed of a composite metal oxide which transmits the ultraviolet rays of (1) and does not substantially emit light by absorbing the ultraviolet rays of 185 nm is formed.

Here, the phosphor coating may have two or more layers. In addition, Al ₂ O ₃ , ZnO, Ti are formed on the inner surface of the valve.
There may or may not be a protective film such as O ₂ .

According to a second aspect of the present invention, the protective layer made of the composite metal oxide is made of a phosphor matrix containing no activator, which absorbs 185 nm ultraviolet light, transmits 254 nm ultraviolet light, and 185 nm. It is formed of a phosphor matrix that does not substantially emit light due to absorption of ultraviolet rays.

According to a third aspect of the present invention, the protective layer formed of the composite metal oxide layer is BaO.Al ₁₂ O ₁₈ , (ZnO).
_1.8・ SiO ₂ , (ZnO) _2.0・ SiO ₂ , Y ₃
It is characterized by being formed of one kind or a mixture of Al ₅ O ₁₂ .

The invention of claim 4 is characterized in that the rated tube wall load of the valve is 500 W / m 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.

[0017]

According to the invention of claim 1, when the protective layer of the composite metal oxide formed on the discharge space side receives the ultraviolet rays of 185 nm and 254 nm of the mercury resonance line, it absorbs 185 nm and the ultraviolet ray of 254 nm. Therefore, the ultraviolet rays of 185 nm are prevented from reaching the phosphor coating on the bulb side, and therefore the phosphor coating is prevented from being deteriorated by the ultraviolet rays.

Moreover, the protective layer made of the above composite metal oxide does not self-deteriorate even when it receives ultraviolet rays of 185 nm, and can protect the phosphor coating from ultraviolet rays of 185 nm for a long period of time, thus improving the luminous flux maintenance factor. To do.

According to the second aspect of the present invention, the protective layer made of the composite metal oxide is made of a phosphor matrix containing no activator and absorbs the 185 nm ultraviolet ray and transmits the 254 nm ultraviolet ray. Moreover, since it is formed of a phosphor matrix that does not emit light even when receiving these ultraviolet rays, it is possible to use the phosphor matrix in the process of manufacturing the phosphor as the composite metal oxide, and it is easy to manufacture the composite metal oxide. Is.

According to the third aspect of the present invention, the protective layer formed of the composite metal oxide layer is formed of BaO.Al ₁₂ O ₁₈ (Zn).
O) _1.8・ SiO ₂ , (ZnO) _2.0・ SiO ₂ ,
Formed from one or a mixture of Y ₃ Al ₅ O ₁₂ , these materials absorb at 185 nm and 25
It has an excellent function of transmitting 4 nm UV light, and it does not undergo self-degradation even when it receives 185 nm UV light. Therefore, the phosphor coating can be protected from 185 nm UV light for a long period of time, and the luminous flux maintenance factor is improved.

According to the invention of claim 4, although it is applied to a high load lamp having a tube wall load of 500 W / m ² or more, ultraviolet rays of 185 nm are cut off, so that the deterioration of the phosphor is good. Can be suppressed. 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 FIG. 2 is an enlarged sectional view of a portion II of FIG. In the figure,
Reference numeral 1 is a transparent arc tube bulb made of soda lime glass. As shown in FIG. 2, a phosphor coating 2 is formed on the inner surface of the bulb 1. This phosphor coating 2 is 18
Light with a wavelength longer than 5 nm, that is, 254 nm of the mercury resonance line
Which emits visible light upon receiving the ultraviolet rays of, for example, antimony / manganese activated halophosphate phosphor (Ca ₅ (PO
₄ ) ₃ (F, Cl): Sb, Mn) or a three-wavelength light emitting phosphor. Ca ₅ (PO ₄ ) ₃ above
In the case of (F, Cl): Sb, Mn phosphor, when it receives an ultraviolet ray of 254 nm, it has a strong emission region for visible light such as 480 nm and 580 nm. The thickness t1 of the phosphor layer 2 may be about 30 to 50 .mu.m, which is the same as the conventional one and is sufficient to emit visible light.

A protective film 10 is formed on the surface of the phosphor coating 2, that is, the surface on the discharge space side. This protective film 1
0 is formed of a composite metal oxide that absorbs 185 nm ultraviolet light, transmits 254 nm ultraviolet light, and does not substantially emit light by absorbing 185 nm ultraviolet light. This composite metal oxide is composed of, for example, a phosphor matrix containing no activator, absorbs 185 nm ultraviolet light, transmits 254 nm ultraviolet light, and is 185 nm.
A phosphor matrix that itself does not substantially emit light by absorption of ultraviolet rays of nm, and specific examples include barium oxide / aluminic acid {BaO.Al ₁₂ O ₁₈ }, zinc oxide / silicate {(Zn
O) _1.8・ SiO ₂ }, {(ZnO) _2.0・ SiO
₂ }, yttrim aluminate {Y ₃ Al ₅ O ₁₂ } or a mixture thereof. The thickness t2 of the protective layer 10 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 attached to these stems 3 and 3.
... is airtightly penetrated. Electrodes 5 and 5 are attached to each well 4 ..., and these electrodes 5 and 5 are formed by a coil made of a tungsten filament. BaO, SrO, and
An electron emitting material (emitter) such as CaO is applied.

The caps 6, 6 are attached to the ends of the valve 1, and the cap pins 7 projecting from the caps 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 surface of the phosphor coating 2 on the discharge space side absorbs 185 nm ultraviolet rays, transmits 254 nm ultraviolet rays, and is 185 nm.
Since the protective film 10 is formed of a composite metal oxide that does not substantially emit light even if it absorbs the ultraviolet light, the protective film 10 blocks ultraviolet rays of 185 nm and
Transmits 54 nm ultraviolet light.

Therefore, ultraviolet rays of 185 nm do not reach the phosphor coating 2 on the bulb wall side, and the phosphor coating 2 is
It is prevented from being deteriorated or deteriorated by receiving 85 nm ultraviolet rays.

Then, 254 reached the phosphor coating 2.
The ultraviolet rays of nm are converted into visible light by this phosphor coating 2 and emitted to the outside through the bulb 1. In addition, the protective film 10 does not emit light by itself, and remains 185 for a long time.
Even when it receives an ultraviolet ray of nm, it does not deteriorate itself, that is, it does not become discolored or colored, and therefore it retains the property of blocking the ultraviolet ray of 185 nm and transmitting the ultraviolet ray of 254 nm for a long time. For this reason, the phosphor coating 2 does not deteriorate for a long period of time, and the constraint maintenance rate can be kept high.

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

For example, a general FL40W type fluorescent lamp has a rated input of 40 W, an arc tube inner diameter of 37 mm and a total length of 1
It is 200 mm and the tube wall load is 290 W / m 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, high output fluorescent lamp FLR60H
・ In the case of DA, the inner diameter of the arc tube is 37m at the rated input of 60W.
m, total length 1200 mm, pipe wall load 430 W / m ²
Is. 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,
A protective film 10 is formed on the inner surface of the phosphor coating 2, and the protective film 10 absorbs ultraviolet rays of 185 nm and is 254 nm.
If it is made of a composite metal oxide that transmits the above ultraviolet rays and does not emit light even if it absorbs the 185 nm ultraviolet rays, the 185 nm ultraviolet rays do not reach the phosphor coating 2, preventing deterioration and deterioration of the phosphor. Therefore, the luminous flux maintenance factor is improved.

Tables 1 and 2 show the results of examining how the luminous flux maintenance factor changes with the lapse of lighting time for such a fluorescent lamp. Table 1 below shows that the phosphor coating 2 is formed of antimony / manganese activated halophosphate phosphor (Ca ₅ (PO ₄ ) ₃ (F, Cl): Sb, Mn). A protective film 10 made of various materials is formed on the surface, and the lighting time is 0 and 10 respectively.
It is the measured value of the result of examining the luminous flux maintenance factor after 0 hours. The thickness t of the phosphor coating 2 is 40 μm, and the protective film 1 is
The thickness t2 of 0 was 10 μm in all.

[0034]

[Table 1]

From Table 1, as in the embodiment of the present invention,
It is confirmed that when the protective layer 10 is laminated on the surface of the phosphor coating 2, the luminous flux maintenance factor is improved as compared with the case where the protective layer 10 is not formed. This is because the protective layer 10 does not absorb and transmit the 185 nm ultraviolet ray, and thus the phosphor coating 2 is not deteriorated by the 185 nm ultraviolet ray, and the protective layer 10 itself is not deteriorated, so that the luminous flux maintenance rate is improved. You can think of it as something.

Further, Table 2 below shows that the phosphor coating 2 is a europume activated strontium borate phosphor (SrB ₄
O ₇ : Eu) and formed on the surface of the phosphor coating 2.
These are the measured values of the results of examining the luminous flux maintenance factor after forming the protective film 10 made of various materials and respectively after the lighting time of 0 and 100 hours. Also in this case, the thickness t of the phosphor coating 2 is 40 .mu.m and the thickness t2 of the protective film 10 is 10 .mu.m.

[0037]

[Table 2]

From Table 2 as well, it is confirmed that when the protective layer 10 is laminated on the surface of the phosphor coating 2, the luminous flux maintenance factor is improved. The protective layer 10 made of the complex metal oxide as described above is specifically made of BaO.Al ₁₂ O ₁₈ , (Zn
O) _1.8・ SiO ₂ , (ZnO) _2.0・ SiO ₂ ,
It is preferably formed of one or a mixture of Y ₃ Al ₅ O ₁₂ . These substances have excellent functions of absorbing 185 nm and transmitting 254 nm ultraviolet rays.
It is a phosphor matrix that does not undergo self-degradation even when it receives 85 nm UV light, and can protect the phosphor coating 2 from 185 nm UV light for a long period of time, contributing to an improvement in the luminous flux maintenance factor.

The protective layer 10 made of the complex metal oxide as described above is made of a phosphor matrix containing no activator and absorbs 185 nm ultraviolet light and 254 nm.
It can be formed of a phosphor matrix that transmits the above ultraviolet rays and does not emit light itself even when absorbing 185 nm ultraviolet rays.

The composite metal oxide composed of this phosphor matrix can be manufactured by using the method for manufacturing a phosphor without mixing an activator, and the manufacture of the composite metal oxide is easy. Moreover, the protective layer 10 can be manufactured by a method similar to that for forming the phosphor coating, and is easily available and manufactured.

An example of a method for producing a composite metal oxide composed of the above phosphor matrix will be described. (1) Manufacturing method of BaO.Al ₁₂ O ₁₈ 19.7 g of BaCO ₃ powder, 60.2 g of γ-Al ₂ O ₃ powder and 1.70 g of AlF ₃ powder were mixed together, and this was mixed with alumina. Put in a crucible, 1 in air
Bake at a temperature of 200 ° C. for 17 hours. Add 4 times the glass beads with an average particle size of 2 mm to this fired mixed powder and 2
Milling was carried out by adding twice the amount of water, and this was suction filtered to 1
Dry at 00 ° C. When this is passed through a 200-mesh sieve, a phosphor matrix made of BaO.Al ₁₂ O ₁₈ is obtained. (2) Method for producing (ZnO) _1.8 · SiO ₂ 24.4 g of ZnO powder, 10.0 g of SiO ₂ powder,
Each is mixed well, placed in an alumina crucible and fired in air at a temperature of 1300 ° C. for 3 hours. The calcined mixed powder is removed from the crucible, passed through a 200 mesh sieve in water, suction filtered and dried. Pass it through a 200 mesh sieve again (ZnO)
_A phosphor matrix composed of _1.8 · SiO ₂ is obtained. _{(3) (ZnO) 2.0 ·} SiO 2 of the method for manufacturing ZnO powder 27.1 g, a SiO ₂ powder and 10.0 g, when prepared by a method the same order of the (2) (ZnO)
_A phosphor matrix composed of 2.0.SiO ₂ is obtained. (4) Method for producing Y ₃ Al ₅ O ₁₂ 16.9 g of Y ₂ O ₃ powder, 11.7 g of γ-Al ₂ O ₃ powder, and 1.70 g of AlF ₃ powder were mixed well. Then, this is placed in an alumina crucible and calcined in air at a temperature of 1250 ° C. for 60 hours. Similar to the method (1), four times the amount of glass beads having an average particle size of 2 mm and twice the amount of water are added to the fired mixed powder for milling. It is suction filtered and dried at 100 ° C. When this is passed through a 200-mesh sieve, a phosphor matrix made of Y ₃ Al ₅ O ₁₂ is obtained.

Therefore, the composite metal oxide composed of these phosphor bases can be manufactured by using the method for manufacturing a phosphor without mixing an activator, and is easy to manufacture. The thickness t1 of the phosphor layer 2 is preferably 30 to 50 .mu.m. If the film thickness t1 of the phosphor layer 2 is less than 30 μm, then 25
The ability to convert 4 nm UV light into visible light is reduced, and
If it exceeds 0 μm, the strength of the coating film is reduced and the film is easily peeled off, or visible light is self-absorbed to reduce the luminous flux, resulting in a decrease in efficiency.

The thickness t2 of the protective layer 10 is 5 to 20.
About μm is preferable. If the thickness t2 of the protective layer 10 is less than 5 μm, the ability to block 185 nm ultraviolet rays is low, and the initial purpose of providing the protective layer 10 cannot be achieved.
If it exceeds 50 μm, problems such as easy peeling occur.

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 as the light source is lit for a long period of time in a state where the luminous flux maintenance ratio is excellent, it is possible to provide an illuminating device having high brightness and excellent life characteristics. it can.

The present invention is not limited to the structure of the above embodiment. That is, as the phosphor constituting the phosphor coating 2, the above-mentioned antimony / manganese activated halophosphate phosphor (Ca ₅ (PO ₄ ) ₃ (F, Cl):
Sb, Mn) and europume activated strontium
Not only the borate phosphor or the three-wavelength emission type phosphor, but all the phosphors used in the fluorescent lamps and the high-pressure mercury lamp that have already been put into practical use can be used.

The phosphor coating 2 may itself have a structure of two or more layers. That is, a phosphor layer made of a three-wavelength light emitting phosphor is provided on the bulb wall side, and a phosphor layer made of an antimony / manganese activated halophosphate phosphor is provided inside the phosphor layer. You may.

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 type 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 mainly composed 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 translucent 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.

[0051]

As described above, according to the invention of claim 1, the protective layer formed of the composite metal oxide absorbs the 185 nm ultraviolet ray of the mercury resonance line and transmits the 254 nm ultraviolet ray. The side phosphor coating is prevented from receiving 185 nm UV radiation and therefore the phosphor coating is prevented from UV degradation. Moreover, the protective layer made of the above-mentioned composite metal oxide does not self-deteriorate even when it receives ultraviolet rays of 185 nm, and can protect the phosphor coating from ultraviolet rays of 185 nm for a long period of time, thus improving the luminous flux maintenance factor.

According to the second aspect of the present invention, the protective layer made of the composite metal oxide is made of a phosphor matrix containing no activator and absorbs the 185 nm ultraviolet ray and transmits the 254 nm ultraviolet ray. In addition, since the composite metal oxide is formed of a phosphor matrix that does not emit light even when it receives these ultraviolet rays, it is possible to use the phosphor matrix in the process of manufacturing the phosphor, and to manufacture and protect the composite metal oxide. The layers are easy to manufacture.

According to the third aspect of the present invention, the protective layer formed of the composite metal oxide layer is formed of BaO.Al ₁₂ O ₁₈ (Zn
O) _1.8・ SiO ₂ , (ZnO) _2.0・ SiO ₂ ,
Formed from one or a mixture of Y ₃ Al ₅ O ₁₂ , these materials absorb at 185 nm and 25
It has an excellent function of transmitting 4 nm UV light, and it does not undergo self-degradation even when it receives 185 nm UV light. Therefore, the phosphor coating can be protected from 185 nm UV light for a long period of time, and the luminous flux maintenance factor is improved.

According to the invention of claim 4, although it is applied to a high-load lamp having a tube wall load of 500 W / m ² or more, ultraviolet rays of 185 nm are blocked, so that the deterioration of the phosphor is good. Can be suppressed. 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 is a side view of a fluorescent lamp showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a II portion in FIG. 1 of the same embodiment.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Arc tube 2 ... Phosphor coating 3 ... Stem 5 ... Electrode 10 ... Protective layer 30 ... Lighting fixture main body 31 ... Lamp socket 32 ... Ballast

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masaaki Tamaya 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research and Development Center

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 including, the phosphor film is mainly formed of a phosphor that absorbs and emits 254 nm ultraviolet light, and the discharge space side of the phosphor film absorbs 185 nm ultraviolet light. And transmits 254 nm ultraviolet light, and 185
A mercury vapor discharge lamp, comprising a protective layer formed of a composite metal oxide that does not substantially emit light when absorbing an ultraviolet ray of nm. 2. The protective layer of the composite metal oxide comprises a phosphor matrix containing no activator, absorbs 185 nm ultraviolet light and transmits 254 nm ultraviolet light.
The mercury vapor discharge lamp according to claim 1, wherein the mercury vapor discharge lamp is formed of a phosphor matrix that does not substantially emit light when absorbing 85 nm ultraviolet light. 3. The protective layer of the composite metal oxide is BaO.
・ Al ₁₂ O ₁₈ , (ZnO) _1.8・ SiO ₂ , (Zn
_{O) 2.0 · SiO 2, Y} 3 Al 5 mercury vapor discharge lamp according to claim 1 or claim 2, characterized in that it is formed by one or mixture of O _12. 4. The rated tube wall load of the valve is 5005 W / m.
^{It is 2} or more, Claim 1 thru | or Claim 3 characterized by the above-mentioned.
1. 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.