JPH0654656B2 - Fluorescent lamp and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention is to deposit a metal oxide powder such as alumina on the inner surface of a bulb, and to fluoresce the metal oxide powder. The present invention relates to a fluorescent lamp formed by stacking body coatings and a method for manufacturing the same.

(Prior Art) In a fluorescent lamp, a fluorescent film is formed on the inner surface of a glass bulb. However, if the phosphor coating is formed directly on the inner surface of the bulb, the binder of the phosphor coating may react with the glass to erode the glass and cause fine cracks, which may cause Problems such as a decrease in mechanical strength and a decrease in luminous efficiency occur.

In order to eliminate such a defect, conventionally, a means for depositing a powder made of a metal oxide such as alumina, silica or titania between the bulb and the phosphor coating has been adopted.

The state of deposition of the metal oxide powder is such that the metal oxide powder is dispersed on the inner surface of the bulb to the extent that the phosphor coating has a portion directly adhered to the inner surface of the bulb without passing through the metal oxide powder. It has been attached.

According to such a structure, the metal oxide powder provided between the bulb and the phosphor coating reduces direct contact between the phosphor coating and the bulb, and therefore the binder of the phosphor coating is used. Prevent valve erosion.

However, the metal oxide powder formed between the bulb and the phosphor coating as described above prevents the binder of the phosphor coating from coming into contact with the bulb. The binding force is reduced, and the phosphor film is easily peeled off.

This tendency is such that the higher the coating density of the metal oxide powder is, the more the binding force of the phosphor coating is prevented from contacting the bulb, so that the phosphor coating is easily peeled off.

By the way, the fluorescent lamp coated with the metal oxide powder as described above may be applied to a ring-shaped fluorescent lamp, and its problems will be described in the case of manufacturing the ring-shaped fluorescent lamp. Usually, a ring-shaped fluorescent lamp of this type is manufactured by the method shown in FIGS. 6 to 9.

That is, in FIG. 6, after cleaning the inner surface of the straight tube type glass bulb 1, the bulb 1 is kept in a substantially vertical posture,
A suspension in which powder such as alumina is dispersed and mixed from the upper end 1a.
Apply 2 to the inner surface of the valve 1 by letting it flow out from the lower end 1b. By drying this and scattering the binder and the like, only the metal oxide powder is dispersed and attached to the inner surface of the valve 1. That is, the alumina powder is attached to the inner surface of the bulb 1 as if sand was scattered.

Next, as shown in FIG. 7, while keeping the valve 1 in a posture in a substantially vertical direction, a suspension 4 containing phosphor powder is flowed from the upper end in the same direction as above to flow the metal oxide. Powder
Apply on top of 3. The phosphor coating 5 is formed on the metal oxide powder 3 by drying and firing it.

Thus, the metal oxide powder 3 and the phosphor coating
The straight tube type glass bulb 1 having the shape 5 is sealed with stems having electrodes (not shown) at both ends.

Then, the valve 1 is heated in a heating furnace (not shown) to be softened, wound around the peripheral surface of the bending drum 6 as shown in FIG. 8 and bent to form an annular shape as shown in FIG. To process.

Next, the inside of the valve 1 is evacuated through an exhaust pipe protruding from the stem, and after activation of the electrodes, mercury and an inert gas are sealed and the exhaust pipe is cut off.

Further, a base is attached to the end of the bulb 1 to complete the fluorescent lamp.

Although the above manufacturing method is well known, in the conventional case, as shown in FIG. 6, in order to apply the suspension 2 of the metal oxide powder to the inner surface of the straight tube type glass bulb 1, 1
Is maintained in a substantially vertical posture, and the suspension 2 of the metal oxide powder is flowed from the upper end 1a. According to such a coating method, the coating thickness of the suspension 2 becomes thicker in the lower portion than in the upper portion of the valve 1, as shown in FIG. Therefore, the adhesion density of the metal oxide powder becomes sparse in the upper part of the valve 1, whereas the adhesion density of the metal oxide powder becomes dense in the lower part. In the drawings, the adhered portions of the metal oxide powder are shown as having different thicknesses, but it should be understood that there is a difference in adhesion density.

On the other hand, when the phosphor coating 5 is formed on the metal oxide powder 3 formed as described above, the straight tube glass bulb 1 is coated with the suspension 2 of the metal oxide powder. Keep the posture in the same direction as the vertical posture,
A suspension 4 containing phosphor powder is flowed from 1a, and a suspension 4 of the phosphor coating 5 is flown on the metal oxide powder 3. As a result, the thickness of the phosphor coating 5 becomes thicker in the lower portion of the bulb 1 than in the upper portion thereof, as shown in FIG. The thickness of the phosphor coating 5 is shown in the figure.

That is, the density of the metal oxide powder 3 is higher in the lower part of the bulb 1 than in the upper part, and the thickness of the phosphor coating 5 formed on the lower part of the bulb 1 is also thicker than in the upper part.

When bending such a bulb 1, in order to prevent the phosphor coating 5 from seeing through due to the elongation of the glass, place the one with the larger thickness of the phosphor coating 5 above the bulb 1 with a large elongation. It has become.

That is, in the bending step shown in FIG. 8, the upper end of the valve 1 which has been softened by heating is clamped by the chuck 7 on the head side, and the lower end is clamped by the chuck 8 of the bending drum 6, and the bending drum 6 is held. The valve 1 is wound around the bending drum 6 by rotating in the direction of arrow A and simultaneously raising in the direction of arrow B. In this case, valve 1
The elongation at the upper end tends to be greater than that at the lower end.

Therefore, the bulb 1 shown in FIG. 7 is turned upside down and the thicker end 1b of the phosphor coating 5 is clamped by the chuck 7 on the head side as shown in FIG. The lower end 1a of the phosphor coating 5 is clamped by the chuck 8 of the bending drum 6, and the thicker end of the phosphor coating 5 is installed in the larger extension. Was there.

(Problems to be Solved by the Invention) However, originally, the greater the film thickness of the phosphor coating 5, the lower the surface tension and the more easily it is peeled off from the bulb. Therefore, the metal oxide powder 3
Is desired, but it is inevitable to prevent the reaction between the valve and the binder.

Further, in the phosphor film 5 which originally has a property of being easily peeled off as the film thickness becomes larger, the metal oxide powder has a higher adhesion density between the phosphor film 5 and the inner surface of the bulb 1 where the thickness is large. If it is interposed, the binding force of the phosphor coating 5 on the bulb 1 is hindered and the phosphor coating 5 is easily peeled off.

Furthermore, while the upper end of the valve 1 extends greatly,
If the phosphor coating 5 is not firmly attached to the bulb 1, the phosphor coating 5 will float and will be very easily peeled off.

Then, the phosphor coating 5 and the bulb 1
If a portion where the metal oxide powder has a high adhesion density is provided between the inner surface and the inner surface, mercury particles may come into contact with the phosphor coating 5 and peel off when the mercury is filled in the exhaust process. Also, there is a drawback that pinholes are easily peeled off due to the adhesion of mercury during lighting.

In the present invention, even if a metal oxide powder is adhered between the inner surface of the bulb and the phosphor coating, a fluorescent lamp capable of preventing the phosphor coating from peeling off, and a manufacturing that can be easily realized. It is intended to provide a method.

[Structure of the Invention] (Means for Solving the Problems) The first aspect of the present invention is to form a phosphor coating on the inner surface of the bulb and to locate the inner surface of the bulb between the bulb and the phosphor coating. In the fluorescent lamp having the metal oxide powder deposited thereon, the deposition density of the metal oxide powder is sparse in the thick portion of the phosphor coating.

A second aspect of the present invention is a method of manufacturing a fluorescent lamp in which a metal oxide powder is deposited on the inner surface of a bulb and a phosphor coating is formed on the inner surface of the bulb to provide a vertical difference between both ends of the bulb. , The suspension of the metal oxide powder is flowed from one end of the valve to apply it to the inner surface of the valve and then it is dried, and then the valve is turned upside down and It is characterized in that a suspension of the phosphor coating is flown from the other end to be applied over the metal oxide powder, and then dried.

(Function) According to the first aspect of the present invention, since the deposition density of the metal oxide powder is sparse in the thick portion of the phosphor coating, which originally has a weak binding strength to the bulb, the bulb of the phosphor coating is The contact area with respect to is increased and the binding strength is increased, and therefore the peeling of the phosphor coating can be prevented.

According to the second aspect of the present invention, since the density of the metal oxide powder becomes sparse in the upper part of the valve during the coating process by the flow of the suspension in which the metal oxide powder is dispersed, the valve is turned upside down. If the suspension of the phosphor coating is flowed from the upper end of the lever and applied over the metal oxide powder,
It is possible to easily form a portion where the density of the metal oxide powder is sparse in the portion where the thickness of the phosphor coating is large.

(Embodiment) The present invention will be described below based on an embodiment shown in FIGS. 1 to 5.

1 to 4 sequentially describe the manufacturing process of the ring-shaped fluorescent lamp, the same members as those of the conventional one are designated by the same reference numerals, and the description thereof will be omitted.

In Fig. 1, after cleaning the inner surface of a straight tube type glass bulb 1, keep this bulb 1 in a substantially vertical position, and from the upper end 1a, flow a suspension 2 containing dispersed alumina powder and let it flow from the lower end 1b. Suspension on the inner surface of valve 1 by draining
Apply 2. When this is dried, the solvent components and the like of the suspension 2 are scattered, and only the alumina powder 3 is attached to the inner surface of the valve 1 as if the sand was scattered.

Next, by turning the valve 1 upside down, as shown in FIG.
Keeping this valve 1 in a vertical position,
The suspension 4 containing the phosphor powder is poured from 1b and the lower end 1a
Flow out from above and apply on the above alumina powder 3.
The alumina powder 3 was obtained by drying and firing this.
A phosphor coating 5 is formed on top of it.

In this way, the alumina powder 3 and the phosphor coating 5
The straight tube type glass bulb 1 having the above-mentioned structure is sealed with a stem having electrodes (not shown) at both ends.

Then, the valve 1 is heated in a heating furnace (not shown) to soften it, and the valve 1 is wound around the peripheral surface of the bending drum 6 as shown in FIG. 3 and bent to form an annular shape as shown in FIG. To process.

In the bending process of FIG. 3 above, the valve 1 shown in FIG.
The head side chuck 7 and the lower end 1b.
Is clamped by the chuck 8 of the bending drum 6, and this bending drum 6 is rotated in the direction of arrow A and at the same time raised in the direction of arrow B, and the valve 1 is wound up on this bending drum 6.

Next, the inside of the valve 1 is evacuated through an exhaust pipe protruding from the stem, and after activation of the electrodes, mercury and an inert gas are sealed and the exhaust pipe is cut off.

Further, a base is attached to the end of the bulb 1 to complete the fluorescent lamp.

According to the manufacturing method as described above, the straight tube type glass bulb 1
When the suspension 2 of alumina powder is made to flow from the upper end 1a while maintaining the vertical posture, the coating thickness distribution of the suspension 2 becomes
As shown, the valve 1 is thicker at the bottom than at the top. Therefore, if the solvent component of the suspension 2 is scattered, the adherence density of the alumina powder becomes sparse at the upper part of the valve 1, and the density of the alumina powder becomes denser at the lower part. This state is displayed as thickness in the drawing,
Actually it is density.

Next, in order to form the phosphor film 5 on the alumina powder 3, the straight tube glass bulb 1 is turned upside down and kept in a substantially vertical posture, and the phosphor powder is mixed from the upper end 1b. Since the suspension 4 thus prepared is applied by flowing, the thickness of the phosphor coating 5 becomes thicker in the lower portion of the bulb 1 than in the upper portion thereof, as shown in FIG.

That is, the density of the alumina powder 3 is higher in the upper part of the bulb 1 than in the lower part of the bulb 1, and the phosphor film formed on this is denser.
On the contrary, the thickness of 5 is thicker at the bottom than at the top of valve 1.

Therefore, if the thickness of the phosphor coating 5 is large,
A portion where the adhesion density of the alumina powder 3 is sparse is provided, and the contact area of the phosphor coating 5 with the bulb 1 is increased to improve the binding strength.

In addition, when bending the bulb 1, in order to prevent the phosphor coating 5 from seeing through due to the elongation of the glass, place the one with the larger thickness of the phosphor coating 5 above the bulb 1 with a large elongation. However, the thicker part of the phosphor coating 5 is provided with a portion of the alumina powder having a lower density as described above, and the binding strength of the phosphor coating 5 with the bulb 1 is strengthened. In the bending step, peeling of the phosphor coating 5 can be prevented even in the portion where the thickness of the phosphor coating 5 is large and the elongation of the bulb is large.

In addition, even if mercury particles come into contact with the thick portion of the phosphor coating 5 during mercury filling in the exhaust process,
It is also possible to prevent the peeling off of the pinhole, and to reduce the pinhole peeling due to the adhesion of mercury during lighting.

Moreover, the combination molding of the density difference of the alumina powder 3 and the thickness difference of the phosphor coating 5 as described above is carried out when the suspension 2 of the alumina powder is flowed and when the suspension 4 containing the phosphor powder is mixed.
It can be formed by turning the valve 1 upside down depending on the case of flowing, and can be manufactured extremely easily without changing the conventional process.

FIG. 5 shows the experimental results for examining the degree of peeling of the phosphor coating during bending in a fluorescent lamp. The applicable lamp is FCL30 / 28, which is a three-wavelength fluorescent lamp, the powder is alumina, and the fluorescent substance is a rare earth fluorescent substance.

A lamp manufactured by the conventional method shown in FIG. 6 and subsequent figures is indicated by a broken line a, and a fluorescent lamp manufactured by the present invention is indicated by a solid line b.
Indicate.

In the lamp manufactured by the conventional method, the alumina powder is deposited at a high density on the portion where the elongation in bending is large. Therefore, if the total amount of the alumina powder deposited on the inner surface of the bulb exceeds 3 mg, the phosphor coating However, according to the present invention, since the alumina powder can be deposited at a low density on the portion having a large bending elongation, even if the total amount of alumina powder deposited on the inner surface of the valve exceeds 4 mg. It was possible to reduce the peeling of the phosphor coating.

Further, the following table shows the results of examining the peeling state of the phosphor coating under various conditions.

In the above table, the size of peeling after impact is SU
It is the size of the peeling of the phosphor coating that occurs when hitting with a scale of S150 mm, and is shown by width and length.

Further, without alumina powder is a lamp in which no alumina powder is provided between the bulb and the phosphor coating, and when the bulb is not turned upside down in the alumina powder adhesion step and the phosphor coating application step, the method of the present invention is different from the conventional method. Shows the case where the valve is turned upside down in the alumina powder adhesion step and the phosphor coating step.

Furthermore, the degassing treatment employs a line seal method when the stem is sealed to the valve, but the valve is already formed by heating the valve to about 250 to 300 ° C. during this sealing step. This is to prevent impurities from being adsorbed on the phosphor coating on the inner surface of the bulb. When impurities such as moisture are adsorbed on the phosphor coating, they are easily peeled off. On the other hand, “without degassing treatment” means that the valve is not heated during the line seal sealing step, and impurities are likely to be adsorbed by the already formed phosphor coating on the inner surface of the valve.

As can be seen from the above table, the effect of the method of the present invention is recognized, and particularly when the degassing treatment is adopted, the effect is remarkable.

The present invention is not limited to the ring fluorescent lamp and the manufacturing method thereof. That is, in the ring fluorescent lamp, the metal oxide powder 3 and the phosphor coating 5
There is a bending step after the formation of the film. In this bending step, peeling of the phosphor coating 5 is a concern, so the condition is severe.

However, the variation in the film thickness of the phosphor coating 5 occurs in the fluorescent lamps of various shapes including the straight tube fluorescent lamp, and the application of the present invention to these fluorescent lamps is also possible. It is possible.

Further, the metal oxide powder of the present invention is not necessarily applied to such an extent that the phosphor coating has a portion directly attached to the inner surface of the bulb without interposing the metal oxide powder,
It can be carried out even when applied in layers.

EFFECTS OF THE INVENTION As described above, according to the first aspect of the present invention, the deposition density of the metal oxide powder is made sparse in the thick portion of the phosphor coating, which originally has a weak binding strength to the bulb. The contact area of the phosphor coating with the bulb is increased and the binding strength is increased, so that the peeling of the phosphor coating can be prevented.

According to the second aspect of the present invention, since the density of the metal oxide powder becomes sparse in the upper part of the valve during the coating process by the flow of the suspension in which the metal oxide powder is dispersed, the valve is turned upside down. If the suspension of the phosphor coating is flowed from the upper end of the lever and applied over the metal oxide powder,
It is possible to easily form a portion where the density of the metal oxide powder is sparse in the portion where the thickness of the phosphor coating is large.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention.
1 to 4 are explanatory views showing the manufacturing steps of the ring-shaped fluorescent lamp in order, FIG. 5 is a characteristic diagram, and FIGS. 6 to 9 are the manufacturing steps of a conventional ring-shaped fluorescent lamp. FIG. 1 …… Valve, 3 …… Metal oxide powder, 5 …… Fluorescent film, 6 …… Bending drum.

Claims (3)

[Claims] 1. A fluorescent coating is formed on the inner surface of the bulb, and the fluorescent coating is positioned between the bulb and the fluorescent coating.
A fluorescent lamp in which a metal oxide powder is deposited on the inner surface of a bulb, wherein the deposition density of the metal oxide powder is sparse in the thick portion of the phosphor coating. 2. The adhered state of the metal oxide powder is such that there is a portion where the phosphor film is directly adhered to the inner surface of the bulb without interposing the metal oxide powder. The fluorescent lamp according to item 1 above. 3. A method of manufacturing a fluorescent lamp in which a metal oxide powder is deposited on the inner surface of a bulb, and a phosphor coating is formed on the inner surface of the bulb. The suspension of the metal oxide powder is poured from one end of the higher side to apply it on the inner surface of the valve and then dried, and then the valve is turned upside down from the other end of the raised valve. A method for manufacturing a fluorescent lamp, comprising: flowing a suspension of a phosphor coating, superposing the metal oxide powder on the metal oxide powder, and then drying the metal oxide powder.