JPH08329893A - Fluorescent lamp and lighting device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a fluorescent lamp with a uniform coating that does not cause film thickness variation or peeling due to uneven coating even when using a water-soluble protective coating material coating solution and phosphor coating solution. The purpose is to do. A protective film 6 made of metal oxide fine particles is provided inside a glass bulb 2 provided with at least a pair of electrodes 4, 4, and a protective film containing calcium oxide or the like is laminated on the protective film 6. 6 is a fluorescent lamp 1 provided with a phosphor film 7 containing a binder 7b made of fine particles of a metal oxide of a substance different from 6, and a lighting fixture D equipped with this fluorescent lamp 1. [Effect] There is no melting of the lower protective film due to the upper layer,
A thin film is prevented from becoming a thin film in whole or part, and a film with a desired film thickness that is almost uniform can be formed in a dense state. In addition, it is possible to provide a fluorescent lamp excellent in appearance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp in which a protective film and a phosphor film are laminated on the surface of a glass bulb.

[0002]

2. Description of the Related Art A fluorescent lamp has a structure in which a glass bulb having a phosphor film formed on its inner surface is provided with electrodes consisting of a filament coil in which a tungsten wire is wound in a double or triple manner, and this bulb is also provided. An inert gas such as argon gas for facilitating the discharge and an appropriate amount of mercury are enclosed therein. Then, this fluorescent lamp causes a discharge to occur in the bulb by passing a current through the electrodes, and generates ultraviolet rays to excite the phosphor film coated on the inner surface of the bulb.
Depending on the type of phosphor, desired light such as white, daylight color, blue color, and pink color is emitted from the lamp.

In recent years, this fluorescent lamp has been promoted to have a high output from the viewpoint of energy saving and resource saving. As a result, the load on the tube wall becomes large, so that blackening occurs early during the life of the fluorescent lamp and the luminous flux is lowered. There is a problem of getting bigger.

Therefore, conventionally, a protective film made of a metal oxide is provided between the glass bulb and the phosphor film to prevent the occurrence of blackening due to the permeation of mercury or ultraviolet rays, thereby suppressing the decrease of the luminous flux. It is known.

Further, in a fluorescent lamp in which a glass bulb is bent in a ring shape, a U shape, a W shape, etc., when the bulb is bent, the phosphor film sinks into the glass to cause a decrease in light emission characteristics. A protective film made of a metal oxide such as alumina (Al ₂ O ₃ ) is provided between the film and the film.

A protective film is formed on the glass bulb as the first layer and a phosphor film is formed on the second layer as a second layer. A coating solution is used to form these coatings. The organic type was mainly used, but from the viewpoint of economy and working environment, the water-soluble type has been widely used.

For example, the conventional binder material for the first layer water-soluble protective coating material coating solution and the second layer water-soluble phosphor coating solution has a pH value of about 5 when dispersed in water. In addition, fine particle alumina having an isoelectric pH value of about 8.5, which causes aggregation in water, was used.

However, in this case, when the first layer water-soluble protective coating material coating liquid is applied and dried to form the protective film, the lower protective film is dissolved when the second layer water-soluble phosphor coating liquid is applied. When the lamp was turned on, unevenness of different brightness was seen on the bulb surface when the lamp was turned on, and the appearance was spoiled. This is because, as shown in a model in FIG. 4A, the protective film 6 is melted out to make the film thickness non-uniform, and the eluted alumina (Al ₂ O ₃ ) remains as small bumps. The phosphor film 7 is composed of the phosphor particles 7a, 7a, ...
, b, 7b, ... Are densely packed, but as a whole, a thin film portion is generated, so that a nonuniform film thickness is formed.

The binder for the second layer water-soluble phosphor coating liquid may be PEO (polyethylene oxide).
When a material that does not maintain viscosity in acidic water with a pH value of 6 or less is used, the protective film of the first layer melts and the viscosity of the binder is lost at the interface with the second layer. Value 5
As a result, the phosphor film in that portion becomes thin, which causes uneven coating.

In order to prevent this decrease in pH value,
When the second layer water-soluble phosphor coating solution is subjected to alkali treatment with ammonia or the like at a pH of about 9 to 10,
Due to the isoelectric point action, ammonia and alumina (Al ₂ O ₃ ) which is a binder coagulate to reduce the binding force and cause the film peeling. In this case,
As shown in a model in (b), the protective film 6 was formed with a substantially uniform film thickness, but the alumina (Al ₂ O) in the phosphor film 7 was formed.
₃ ) Aggregation (pieces) 7c, 7c, ... into fine particles 7b, 7b ,.
And the state of the phosphor film 7 was rather rough and peeling occurred.

[0011]

As described above, in the conventional water-soluble coating solution for protective film substance and phosphor coating solution, the lower layer is melted out by the upper layer solution, so that a film having a uniform thickness cannot be formed. There was a problem such as peeling and peeling.

The present invention eliminates the above-mentioned problems and provides a uniform coating film which is free from unevenness in film thickness and peeling due to uneven coating even when a water-soluble protective coating material coating solution and phosphor coating solution are used. An object is to provide a fluorescent lamp.

[0013]

The fluorescent lamp according to claim 1 of the present invention comprises a glass bulb, at least a pair of electrodes provided on the bulb, a discharge medium enclosed in the bulb, and A protective film formed of fine metal oxide particles inside the bulb, and a multilayer coating on this protective film, a binder powder was added and mixed to the phosphor powder on which a coating layer of metal oxide containing calcium oxide was formed. It is characterized by comprising a formed phosphor film.

The fluorescent lamp according to claim 2 of the present invention is
A glass bulb, at least a pair of electrodes provided on the bulb, a discharge medium enclosed in the bulb, a protective film formed of metal oxide fine particles on the inner surface of the bulb, calcium oxide (CaO), Titanium oxide (Ti
O ₂ ), at least one selected from silicon oxide (SiO ₂ ), and a phosphor powder to which a binder containing metal oxide fine particles different from the above-mentioned protective film is added and mixed is formed on the protective film. It is characterized in that it is provided with a phosphor film that is formed by stacking two layers.

The fluorescent lamp according to claim 3 of the present invention comprises:
It is characterized in that the coating solution for the water-soluble phosphor film has a higher pH value than the coating solution for the water-soluble protective film.

The fluorescent lamp according to claim 4 of the present invention is
The protective film material is alumina (Al ₂ O ₃ ), titanium oxide (T
It is characterized in that it is at least one selected from iO ₂ ) and zinc oxide (ZnO).

The fluorescent lamp according to claim 5 of the present invention comprises:
It is characterized in that alumina (Al ₂ O ₃ ) is added to the binder material.

The fluorescent lamp according to claim 6 of the present invention comprises:
A glass bulb, at least a pair of electrodes provided on the bulb, a discharge medium enclosed in the bulb, a protective film formed of fine particles of metal oxide formed inside the bulb, and a protective film on the protective film. And a phosphor film formed by a water-soluble phosphor film coating liquid obtained by adding and mixing a binder having different pH values when the metal oxide fine particles of the protective film are dispersed in water. It is characterized by being.

The fluorescent lamp according to claim 7 of the present invention comprises:
A glass bulb, at least a pair of electrodes provided on the bulb, a discharge medium enclosed in the bulb, a protective film formed of fine particles of metal oxide formed inside the bulb, and a protective film on the protective film. And the isoelectric point p of the metal oxide fine particles of the above protective film is agglomerated in water during water dispersion.
And a phosphor film formed of a water-soluble phosphor film coating liquid obtained by adding and mixing binders having different H values.

The fluorescent lamp according to claim 8 of the present invention comprises:
A glass bulb, at least a pair of electrodes provided on the bulb, a discharge medium enclosed in the bulb, a protective film formed of fine particles of metal oxide formed inside the bulb, and a protective film on the protective film. And a phosphor film formed by a water-soluble phosphor film coating liquid containing a phosphor as a main component, which has a protective substance having different pH values when the metal oxide fine particles of the protective film are dispersed in water. It is characterized by having and.

The fluorescent lamp according to claim 9 of the present invention is
A glass bulb, at least a pair of electrodes provided on the bulb, a discharge medium enclosed in the bulb, a protective film formed of fine particles of metal oxide formed inside the bulb, and a protective film on the protective film. And the isoelectric point p of the metal oxide fine particles of the above protective film is agglomerated in water during water dispersion.
It is characterized in that it is provided with a phosphor film formed by a water-soluble phosphor film coating liquid whose main component is a phosphor having a protective substance having a different H value attached to its surface.

According to a tenth aspect of the present invention, in the fluorescent lamp, the pH value of the binder substance in the coating solution for the water-soluble phosphor film forming the phosphor film is such that the fine particles of the metal oxide forming the protective film. It is characterized in that it is higher than the pH value when dispersed in water.

The fluorescent lamp according to claim 11 of the present invention is the fluorescent material according to claim 6, wherein the isoelectric point pH of the binder substance in the coating solution for the water-soluble phosphor film forming the phosphor film.
It is characterized in that the value is higher than the pH value of the isoelectric point of the metal oxide fine particles forming the protective film when dispersed in water.

According to a twelfth aspect of the present invention, in the fluorescent lamp according to the sixth to ninth aspects, the protective film material is selected from alumina (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and zinc oxide (ZnO). It is characterized by being at least one of the

According to a thirteenth aspect of the present invention, in the fluorescent lamp according to any of the sixth to ninth aspects, the binder material is calcium oxide (CaO), alumina (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), It is characterized by being at least one selected from silicon oxide (SiO ₂ ).

An illumination device according to claim 14 of the present invention is
The lighting device main body is provided with the fluorescent lamp according to any one of claims 1 to 13 installed in the main body.

[0027]

In the inventions of claims 1 to 13, the pH value when the lower layer protective film-forming substance is dispersed in water is acidic, and the isoelectric point, that is, the repulsive force between particles at the time of water dispersion is weakened to cause aggregation. A protective film was formed on the inside of the bulb by using a substance having an alkaline pH value that facilitates the operation. In addition, the upper layer is alkalized with a water-soluble phosphor liquid to have an isoelectric point or higher,
By the isoelectric focusing action on the lower layer of the upper layer liquid, it is possible to prevent the lower protective film from leaching out, and to prevent the lower protective film from becoming a thin film in whole or in part, without causing small pieces to hit.

Further, by controlling the pH and the substance of the film or the film-forming substance, while preventing the lower layer from leaching out, for example, when the pH value of the upper layer phosphor liquid is made alkaline, the pH value is the binder. By selecting the binder substance and the protective film forming substance so as to be different from the isoelectric point, the decrease of the binding force due to the agglomeration of the binder substance is prevented and a strong phosphor film is formed on the protective film. can do.

The film formed of the above-mentioned substances prevents the occurrence of blackening due to the penetration of mercury or ultraviolet rays, and in the fluorescent lamp in which the glass bulb is bent into a ring shape, a U shape, a W shape, etc., It is possible to prevent the phosphor film from sinking into the glass at the time of bending the bulb and lowering the bulb strength.

Furthermore, in the fourteenth aspect of the invention, a lamp is attached to the lighting device, and the same operation as that of the invention of any one of the first to eighth aspects is achieved.

[0031]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a partially cutaway front view showing one end side of a straight tube fluorescent lamp according to the present invention, and FIG. 2 is an explanatory view schematically showing a bulb and a coating portion which are essential parts in an enlarged manner.

In the figure, reference numeral 1 denotes a fluorescent lamp, and an electrode 4 is provided between a pair of lead wires 3 and 3 at both ends of a glass bulb 2 of the lamp 1 (the other end is not shown because the other end is also the same). The stem 5 including the constituent filament coil is sealed.

Inside the bulb 2, a protective film 6 is formed on the first layer and a phosphor film 7 is formed on the second layer so as to be overlaid on the protective film 6. The first-layer protection film 6 is made of, for example, an alumina (Al ₂ O ₃ ) film, and the second-layer phosphor film 7 is, for example, three-wavelength emission type rare earth phosphor powders 7a, 7a, ... And calcium oxide ( CaO) fine particles 7
b, 7b, ... And a mixture thereof.

A discharge medium composed of mercury and an inert gas such as argon is enclosed in the bulb 2.
The base 8 is joined to the end sealing portion 11, and lead wires 3 and 3 (not shown) are electrically connected to the base 8.

The protection film 6 and the phosphor film 7 are formed as follows. The protective film 6 is, for example, fine-grained alumina (Al ₂
O ₃ ) is dispersed in water to have a pH value of about 5, and a water-soluble protective film coating (suspension) solution having an isoelectric point pH value of 8 to 9 that causes aggregation in water during water dispersion is formed into a straight pipe type With the valve vertically supported, the above-mentioned protective film coating liquid is poured from the upper opening to coat the inner surface. Then, after drying, it is baked in a heating furnace or the like to form the first-layer protective film 6.

Next, for the phosphor film 7, for example, a PEO binder dissolved in water, a rare-earth phosphor powder of three-wavelength emission type, and fine particles of calcium oxide (CaO) having a particle diameter of 0.01 to 1 μm are dispersed in water. Then, the dispersion liquid having a pH value of about 12 is mixed to prepare a water-soluble phosphor film coating (suspension) liquid having a pH value of about 9, and the fluorescent light is applied from the opening of the vertically supported bulb as described above. The body membrane coating solution is poured and coated on the first layer. Then, after being dried, it is baked in a heating furnace or the like to form the phosphor film 7 of the second layer.

In this way, the protective film 6 and the phosphor film 7 are formed.
The valve 2 thus formed is completed through a normal step of sealing the stem 5 to the end, a step of exhausting the inside of the valve 2 and mercury, an inert gas filling step, an exhaust pipe closing step, a base attaching step, and the like.

When the fluorescent lamp 1 having such a structure is mounted in a socket and is turned on by turning on a power source, the fluorescent lamp 1 is discharged between the electrodes 4 and 4 by the operation of a lighting circuit, and the lamp 1 emits light to a predetermined level. Is illuminated.

Then, by selecting the pH value of the water-soluble coating liquid to be overlaid as described above, that is, the pH value of the phosphor film 7 of the second layer is set to be smaller than that of the protective film 6 of the first layer. By making the alkalinity higher, the protective film 6 of the first layer is not melted out and the small pieces are not bumped. This is shown in Figure 2.
As shown in a model in (a), the protective film 6 is formed to have a substantially uniform film thickness without melting, and the phosphor film 7 is formed between the phosphor powders 7a, 7a, ... , 7b, ...
Are formed with a substantially uniform film thickness in a densely packed state.

When a PEO binder is used, it is neutralized by the alkaline pH of the binder and the acidic pH of the first layer protective film 6, so that the first layer protective film 6 and the second layer are neutralized. The viscosity of the PEO binder does not decrease at the interface with the phosphor film 7 of the eye, and it is possible to prevent the PEO binder from becoming a thin film entirely or partially, and obtain a desired film thickness.

Further, there is no problem that the gap between the phosphor particles due to the decrease in the viscosity of the binder is eliminated, a dense film is formed, and the luminous efficiency (total luminous flux) is reduced.

In the above embodiment, the protective film 6 of the first layer is made of alumina (Al ₂ O ₃ ) which is acidic in water, and the fluorescent substance film 7 of the second layer is made of calcium oxide Although CaO) is used, the binder material for the second layer may be a mixture of calcium oxide (CaO) and alumina (Al ₂ O ₃ ). In this case, as shown in a model in FIG. 2 (b), minute elution is seen in the protective film 6, and alumina (Al ₂ O ₃ ) fine particles 7b, 7b, ... Some agglomeration (piece) 7c, ...
The phosphor film 7 was slightly rough, but was formed to have a substantially uniform film thickness, and there was no problem in practical use.

The binder substance is not limited to calcium oxide (CaO), but calcium hydroxide (Ca (OH)
₂ ) Water-soluble saturated solution (pH value 12) (which becomes calcium oxide after film formation), titanium oxide (TiO ₂ ) (pH value 7 to 8, isoelectric point pH value 5 to 7), silicon oxide (Si
Other substances such as O ₂ ) (pH value 7 to 8, isoelectric point pH value 5 to 7) were tested with an alkaline substance when dispersed in water, but no problem was found.

Also, titanium oxide (TiO ₂ ) which becomes an alkali in the first layer, and alumina (Al which becomes an acid in the second layer).
₂ O ₃ ) may be used in combination. However, in this case, it is necessary to select a binder that does not cause a decrease in the viscosity of the binder. Further, the protective film and the binder-forming substance are not composed of exactly the same substance such as alumina (Al ₂ O ₃ ) and alumina (Al ₂ O ₃ ), but partially contain the same substance. For example, alumina (Al ₂ O ₃ ) is used as a protective film, and calcium oxide (CaO) is used as a binder substance and alumina (Al ₂ O ₃ ) is used.
What is necessary is just to add.

Further, in the above-mentioned embodiment, a binder substance composed of calcium oxide (CaO) dispersed in water was mixed to form a phosphor film suspension (coating) liquid. However, the binder substance was formed on the surface of the phosphor substance. You may form as a coating layer.

For this, for example, the same protective film substance coating solution as described above is prepared to form a protective film. The phosphor film is a PEO binder dissolved in water and has a particle size of 0.01 to 0.0.
Prepare a phosphor substance with a binder substance consisting of a mixture of alumina (Al ₂ O ₃ ) in the form of fine particles of 2 μm and calcium oxide (CaO) on the surface, and suspend the phosphor film with a pH value of about 9 (Coating) Make a liquid, apply to the bulb as described above and bake to form a phosphor film, seal the bulb, exhaust the air,
A fluorescent lamp is manufactured through the prescribed process.

The coating layer made of the binder substance formed on the surface of the phosphor substance is adhered by the suspension, or a coating formed by applying the binder substance by alkoxide and baking it. It may be a layer.

The coating film of this fluorescent lamp did not melt out the protective film of the first layer and the occurrence of small-sized bumps, as described above.

Further, even when a PEO binder is used, for example, since it is neutralized by the alkaline pH of the phosphor film binder and the acidic pH of the first layer protective film, the first layer protective film 6 is used. Graininess of the PEO binder does not deteriorate at the interface between the second layer phosphor film 7 and the second layer, and it is possible to prevent the PEO binder from becoming a thin film in whole or in part and obtain a desired film thickness.

In addition, when the pH adjusting agent was added during the normal pH adjustment, the binding strength was lowered due to the aggregation of the alumina (Al ₂ O ₃ ) binders. The cohesion with alumina (Al ₂ O ₃ ) as a binder improves the binding strength and prevents peeling.

[0051] Further, those of the first layer of the protective film is formed of titanium oxide (TiO ₂₎ or zinc oxide (ZnO) has an absorption of ultraviolet, decrease in luminous flux is small. In this case, for example, a titanium oxide (Ti
O ₂ ) or zinc oxide (ZnO) powder and APMA (acrylic polymethyl acetate) binder are suspended in the coating solution to form a film, and a second phosphor film is formed. It can be formed by forming from a phosphor film coating liquid in which a wavelength type rare earth phosphor and a PEO (polyethylene oxide) binder are suspended.

Also in the case of a film laminated using such a substance, the PEO binder in the second layer is A in the lower layer.
Since the protective film formed by the PMA binder is not melted and titanium oxide (TiO ₂ ) or zinc oxide (ZnO) does not diffuse into the phosphor film, a fluorescent lamp with improved luminous characteristics without a decrease in luminous flux is provided. can get.

Further, in the above-mentioned embodiments, the phosphor film is explained by using the tri-wavelength type rare earth phosphor, but the phosphor is not limited to the tri-wavelength type phosphor, but may be, for example, calcium halophosphate phosphor. Good.

In this case, for example, 100 g of calcium halophosphate phosphor, 120 g of PEO powder as a binder dissolved in pure water at a concentration of 0.6% and an appropriate amount of a surfactant added, and alumina (Al ₂ O ₃ )
Was mixed well with 2% by weight of phosphor added to prepare a phosphor film suspension (coating) solution. At this time, the pH value of this phosphor film suspension (coating) solution was about 5.9. The pH value of the phosphor film suspension (coating) liquid can be adjusted by appropriately adding an aqueous solution of ammonia.

By the way, p of this phosphor film suspension (coating) liquid is used.
Adjust the H value to 6, 7, 8, 9, and 10 immediately after adjustment and 1
After a week, the coating was applied to a valve and the appearance and coating strength of the coating film were examined. Regarding the appearance of the coating film,
When the value is 10, the surface is rough, and when the first protective film is made of titanium oxide (TiO ₂ ) or zinc oxide (ZnO), it has an ultraviolet absorbing function and the luminous flux is lowered. Few. In this case, for example, a titanium oxide (TiO ₂ ) or zinc oxide (ZnO) powder and APMA are used as the first protective film.
(Acrylic polymethylacetate) is formed from a protective material coating solution in which a binder is suspended to form a film, and a second-layer phosphor film is formed of a triple-wavelength rare earth phosphor and a PEO (polyethylene oxide) binder. A film can be formed by forming from a phosphor film coating solution in which and are suspended.

Also in the case of a film laminated using such a substance, the PEO binder of the second layer is A of the lower layer.
Fluorescent lamp with improved emission characteristics that does not melt the protective film formed with PMA binder and does not diffuse titanium oxide (TiO ₂ ) or zinc oxide (ZnO) into the phosphor film, thus preventing luminous flux from decreasing. Is obtained.

Further, in the above-mentioned embodiments, the phosphor film is explained by using the tri-wavelength type rare earth phosphor, but the phosphor is not limited to the tri-wavelength type phosphor, but may be, for example, calcium halophosphate phosphor. Good.

In this case, for example, 100 g of calcium halophosphate phosphor, 120 g of PEO powder as a binder dissolved in pure water at a concentration of 0.6% and an appropriate amount of surfactant added, and alumina (Al ₂ O ₃ )
Was mixed well with 2% by weight of phosphor added to prepare a phosphor film suspension (coating) solution. At this time, the pH value of this phosphor film suspension (coating) solution was about 5.9. The pH value of the phosphor film suspension (coating) liquid can be adjusted by appropriately adding an aqueous solution of ammonia.

By the way, p of this phosphor film suspension (coating) liquid is used.
Adjust the H value to 6, 7, 8, 9, and 10 immediately after adjustment and 1
After a week, the coating was applied to a valve and the appearance and coating strength of the coating film were examined. Regarding the appearance of the coating film,
Roughness occurred at a value of 10, and one week later, at a pH value of 9 and 10. Regarding the coating strength, all of the ones having a pH value of 6 to 10 were good immediately after the adjustment, but a little peeling occurred at a pH value of 9 or 10 after one week, and generally, the pH value range of 6 to 8 was obtained. It was confirmed that there was no problem with the appearance and coating strength of the coated film within the range.

FIG. 3 is an explanatory view showing an example of an illuminating device using the straight tube type fluorescent lamp of the present invention. The lighting device shown in the drawing is a lighting fixture, and in the drawing, D1 is a lighting fixture main body, and a lighting device such as a fixture (not shown) for a building, a power supply connection mechanism, a ballast D2, etc. is provided in the main body D1. The lamp socket D3 is stored under the main body D1.
D3 is attached and the fluorescent lamp 1 is attached between them. The fluorescent lamp 1 is supported by the sockets D3 and D3, and is supplied with power via the power supply connection mechanism, the ballast D2 and the sockets D3 and D3, and can be stably lit.

The present invention is not limited to the above embodiment. For example, fluorescent lamps are not limited to straight tubes,
The present invention can also be applied to a ring-shaped, U-shaped, W-shaped, bent-type lamp in which a plurality of straight tubes are connected, or a plate-shaped lamp. Further, the present invention is not limited to general fluorescent lamps, and can of course be applied to a rapid start type fluorescent lamp in which a transparent conductor film is provided on the inner surface of a bulb and a protective film and a phosphor film are formed on the conductor film. It is effective in preventing blackening of the coating.

The substance forming the protective film is not limited to those described in the above embodiment. Then, not only one kind but also a mixed kind material containing at least one kind selected from these may be mixed and used. Further, the substance of the binder forming the phosphor film may be titanium oxide (TiO ₂ ) or silicon oxide (SiO ₂ ) in addition to those described in the above embodiment, and
Not at least one but at least one selected from these,
You may mix and use a multiple substance.

Further, although the fluorescent lamp is described as having a hot cathode type electrode using a filament coil, it does not matter whether it is a cold cathode type electrode or an external electrode instead of an internal electrode.

[0064]

According to the inventions of claims 1 to 13,
By raising the pH value of the upper phosphor film to be higher than the pH value of the lower protective film, it is possible to prevent the lower protective film from being melted by the upper layer and to prevent a thin film in whole or in part. It is possible to provide a fluorescent lamp which is capable of forming a film having a desired film thickness that is substantially uniform in a dense state, has no small-sized bumps, has no uneven brightness, and has excellent emission characteristics and appearance.

Further, the film is prevented from being blackened due to the penetration of mercury or ultraviolet rays, and in a fluorescent lamp having a bent glass bulb, the phosphor film is prevented from sinking into the glass when the bulb is bent. Therefore, it is possible to provide a fluorescent lamp excellent in luminous flux maintenance rate and appearance.

Further, the phosphor film prevents undesired agglomeration of the binder to reduce the decrease in luminous flux, and the phosphor can be firmly coated and adhered.

Furthermore, in the invention of claim 14, the lamps of claims 1 to 13 can be turned on without impairing the characteristics and appearance.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing one end side of a straight tube fluorescent lamp according to the present invention.

2 (a) and 2 (b) are explanatory views schematically showing an enlarged model of a bulb and a coating portion which are essential parts of the lamp of the present invention.

FIG. 3 is an explanatory diagram showing an embodiment of a lighting device (lighting device) according to the present invention.

4 (a) and 4 (b) are enlarged schematic explanatory views of a bulb and a coating portion of a conventional fluorescent lamp.

[Explanation of symbols]

 1: Fluorescent lamp 2: Glass bulb 3: Lead wire 4: Electrode (filament coil) 5: Stem 6: Protective film 7: Phosphor film 7a: Phosphor 7b: Binder 7c: Aggregate D: Illuminator (illumination Equipment)

Claims (14)

[Claims] 1. A glass bulb; at least a pair of electrodes provided on the bulb; a discharge medium sealed in the bulb; a protective film formed of metal oxide fine particles inside the bulb; A phosphor film formed by adding and mixing a binder to a phosphor powder having a coating layer of a metal oxide containing calcium oxide formed on the protective film. Fluorescent lamp to do. 2. A glass bulb; at least a pair of electrodes provided on the bulb; a discharge medium enclosed in the bulb; a protective film formed on the inner surface of the bulb with metal oxide fine particles; A binder containing at least one selected from calcium (CaO), titanium oxide (TiO ₂ ) and silicon oxide (SiO ₂ ) and containing metal oxide fine particles different from the above protective film was added and mixed. A phosphor film formed by stacking phosphor powder on the protective film;
A fluorescent lamp comprising: 3. The fluorescent lamp according to claim 1, wherein the coating solution for the water-soluble phosphor film has a higher pH value than the coating solution for the water-soluble protective film. 4. The protective film material is alumina (Al ₂ O ₃ ),
The fluorescent lamp according to claim 1, wherein the fluorescent lamp is at least one selected from titanium oxide (TiO ₂ ) and zinc oxide (ZnO). 5. The fluorescent lamp according to claim ₂ , wherein alumina (Al ₂ O ₃ ) is added to the binder material. 6. A glass bulb; at least a pair of electrodes provided on the bulb; a discharge medium enclosed in the bulb; and a protective film formed inside the bulb and containing fine particles of metal oxide. ; Overlaying this protective film,
And a phosphor film formed of a water-soluble phosphor film coating liquid obtained by adding and mixing binders having different pH values when the metal oxide fine particles of the protective film are dispersed in water. And a fluorescent lamp. 7. A glass bulb; at least a pair of electrodes provided on this bulb; a discharge medium enclosed in the bulb; and a protective film formed inside the bulb and containing fine particles of metal oxide. ; Overlaying this protective film,
A phosphor film formed of a water-soluble phosphor film coating liquid obtained by adding and mixing a binder having a different isoelectric point pH value in which agglomeration of the metal oxide fine particles of the protective film in water during water dispersion occurs. A fluorescent lamp characterized by being provided. 8. A glass bulb; at least a pair of electrodes provided on the bulb; a discharge medium enclosed in the bulb; and a protective film made of metal oxide fine particles formed inside the bulb. ; Overlaying this protective film,
A phosphor film formed of a water-soluble phosphor film coating liquid having a phosphor as a main component and having a protective substance having a different pH value when the metal oxide fine particles of the protective film are dispersed in water. Fluorescent lamp characterized by having. 9. A glass bulb; at least a pair of electrodes provided on the bulb; a discharge medium sealed in the bulb; and a protective film formed inside the bulb and containing fine particles of metal oxide. ; Overlaying this protective film,
Fluorescence formed by a water-soluble phosphor coating liquid containing a phosphor having a protective substance having a different isoelectric pH value as a main component, which causes aggregation of the metal oxide fine particles in the protective film in water when dispersed in water A fluorescent lamp comprising: a body membrane; 10. The pH value of the binder substance in the water-soluble phosphor film coating solution for forming the phosphor film is higher than the pH value of the metal oxide fine particles for forming the protective film when dispersed in water. The fluorescent lamp according to any one of claims 6 to 9, characterized in that. 11. The pH value of the isoelectric point of the binder substance in the coating solution for the water-soluble phosphor film forming the phosphor film is the pH of the isoelectric point of the metal oxide fine particles forming the protective film when dispersed in water. The fluorescent lamp according to any one of claims 6 to 9, which has a higher value than the value. 12. The protective film material is alumina (Al
₂ O ₃ ), titanium oxide (TiO ₂ ), zinc oxide (Zn
The fluorescent lamp according to any one of claims 6 to 9, which is at least one selected from O). 13. The binder material is calcium oxide (Ca).
O), alumina (Al ₂ O ₃ ), titanium oxide (Ti
10. The fluorescent lamp according to claim 6, wherein the fluorescent lamp is at least one selected from O ₂ ) and silicon oxide (SiO ₂ ). 14. A lighting device, comprising: a lighting device main body; and the fluorescent lamp according to claim 1 installed in the main body.