JPH03163731A - Manufacture of ultraviolet ray suppressing lamp - Google Patents

Abstract

PURPOSE:To unify the thickness of a ultraviolet ray absorbing film by coating a coating liquid containing a ultraviolet ray absorbing material on the outer surface of a bulb, holding the bulb at the attitude to keep an tube axis vertical to dry the above coating liquid, coating the above coating liquid on the outer surface of the bulb again, vertically reversing the bulb, holding it at the attitude to keep the tube axis vertical, and drying the coating liquid. CONSTITUTION:A coating liquid of a ultraviolet ray absorbing material is sprayed through shower nozzles 20.... The coating liquid sprayed on the outer face of a bulb 1 flows down along the outer face of the bulb 1. The bulb 1 is held at the attitude to keep a tube axis vertical, and it is naturally dried at the room temperature. The bulb 1 is reversed upside down so that one base 4a is located below and the other base 4b is located above, and the bulb 1 is supported at the attitude to keep the tube axis vertical. The coating liquid of the above ultraviolet ray absorbing material is sprayed through shower nozzles 21... at this attitude. After the coating liquid of the ultraviolet ray absorbing material is coated on the outer surface of the bulb 1, it is heated in a heating furnace or the like to bake the coated film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing an ultraviolet suppressing lamp in which an ultraviolet absorbing coating is formed on the outer surface of the bulb.

(Prior Art) Fluorescent lamps (NU lamps) for preventing color fading have been conventionally used as illumination light sources in places such as department stores, art museums, and museums where care must be taken to prevent fading of products and displayed items.

This kind of anti-fading fluorescent lamp has a coating containing an ultraviolet absorbing material formed on the inner or outer surface of the bulb, and the ultraviolet absorbing coating absorbs ultraviolet rays of 400 nm or less emitted through the bulb, and the ultraviolet rays are exposed to the outside. It has the effect of reducing the amount of radiation emitted.

As proposed in Japanese Patent Application No. 1-37686, the present applicants have proposed a lamp with such an ultraviolet absorbing film formed by adding fine powder of an ultraviolet absorbing material consisting of titanium oxide and zinc oxide and a binder to the outer surface of the bulb. We have developed a technology to shape the film.

This material has advantages such as high ultraviolet absorption performance, good visible light transmittance, and good color rendering properties.

By the way, when forming such a UV-absorbing film on the outer surface of a bulb, conventionally, a coating solution is prepared by dissolving fine powder of an ultraviolet-absorbing substance made of titanium oxide and zinc oxide in a solvent, and then this coating solution is used. is applied to the outer surface of the bulb by brushing, spraying, dipping, or curtain flow coating, followed by drying and baking.

In this case, after applying the coating liquid to the outer surface of the valve, place the valve on a roller with the tube axis in a horizontal position, and use the rotation of the roller to rotate the valve in a horizontal position to spread the coating liquid over the entire surface. I was trying to make it work.

(Problem to be Solved by the Invention) However, according to the above coating method, the coating liquid applied to the outer surface of the bulb may form streaks in the circumferential direction due to variation in the rotational speed of the bulb or centrifugal force. . This is because when brushing, spraying, dipping, or curtain flow coating methods are used as the above coating methods, the coating solution is applied so thickly that it drips, and the excess coating solution drains away. This will create circumferential lines. As a result, variations in the thickness of the ultraviolet absorbing film and uneven coating occur, resulting in variations in ultraviolet blocking and visible light transmitting performance.

In order to apply the coating solution to an extent that does not cause dripping, the coating must be applied in multiple steps, which increases the number of work steps and takes time.

The present invention has been made based on the above circumstances, and an object thereof is to provide a method for manufacturing an ultraviolet suppressing lamp in which the thickness of the ultraviolet absorbing film formed on the outer surface of the bulb is uniform.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention has a structure in which the outer surface of the bulb is
A coating solution containing an ultraviolet absorbing substance consisting of at least one of titanium oxide, zinc oxide, and cerium oxide is applied, and the bulb is held in a position where the tube axis is vertical to dry the coating solution, and then the bulb is applied again. The above-mentioned coating liquid is applied to the outer surface of the tube, and the valve is held upside down from the above-mentioned position so that the tube axis is perpendicular to dry the coating liquid.

(Function) According to the present invention, the coating liquid applied to the outer surface of the bulb flows downward due to gravity during the drying process while holding the tube axis of the bulb in a vertical position, so that the coating liquid applied to the outer surface of the bulb flows downward due to gravity. However, during the process of drying the valve by holding it upside down and in an orientation where the tube axis is vertical, the coating liquid applied to the outer surface of the bulb is removed from the opposite side from the above. The film thickness on the lower side, which is the end portion of the film, is thicker, so that the film thickness can be made substantially uniform as a whole.

(Example) The present invention will be described below based on an example shown in the drawings.

FIGS. 3 and 4 show the finished fluorescent lamp for preventing fading, and in the figures, 1 is a straight glass bulb. A phosphor coating 2 is provided on the inner surface of the bulb 1, and filament electrodes 3, 3 are sealed at both ends of the bulb 1.

Further, at both ends of the valve 1, there are caps 4 a s 4 b.
The base pins 5, 5 protruding from the end faces of these bases 4a, 4b are electrically connected to the electrode 3.

Inside the bulb 1, a predetermined amount of mercury and an inert gas such as argon are sealed.

A fading prevention coating 6 is formed on the outer surface of the bulb 1.

This anti-fading coating 6 is formed by coating the outer surface of the bulb 1 with an ultraviolet absorbing substance consisting of at least one of titanium oxide, zinc oxide, and cerium oxide, and the manufacturing method thereof will be described below.

First, a phosphor coating is formed by applying a phosphor paint to the inner surface of the bulb 1, drying it, and baking it.

Next, a mount stem to which electrodes 3, 3 are attached in advance is sealed to the openings at both ends of the bulb 1, thereby closing the openings at both ends of the bulb 1 with the mount stems.

Then, the inside of the valve is evacuated using an exhaust pipe protruding from the mount stem, and then an inert gas such as mercury or argon is introduced into the valve to seal and cut the exhaust pipe.

After that, the caps 4a and 4b are placed on both ends of the bulb 1, the lead wires connected to the electrodes 3 and 3 are connected to the cap pin 5, and the caps 4a and 4b are attached to the bulb with an adhesive (base cement). Join both ends of 1.

This results in a fluorescent lamp similar to a normal fluorescent lamp.

Next, the caps 4a and 4b are masked and hidden, the outer surface of the bulb 1 is exposed, and a solvent of an ultraviolet absorbing substance is applied to the outer surface of the bulb 1.

The coating liquid may be, for example, tetraethoxysilane, isobrobyl alcohol, and 0.0%. After IN hydrochloric acid is mixed and reacted at a predetermined temperature with stirring to hydrolyze tetraethoxysilane, isopropyl alcohol is added to prepare a tetraethoxysilane hydrolysis solution, which is used as a binder solution.

Zinc oxide powder having a particle size of 0.01 pm is mixed with this binder solution, and the mixture is stirred and dispersed in a ball mill to prepare a coating solution.

Such a coating liquid is applied to the outer surface of the valve 1 with the caps 4a and 4b masked.

This application method may be a brushing method, a spray method, a dipping method, a curtain flow method, or the like, but in the case of this example, as shown in FIG. 1 and FIG. It is sprayed from nozzles 20 and 21...

In this case, the lamps have respective bases 4 a s 4 b
are supported by chucks 22 and 23, with one mouthpiece 4a positioned above and the other mouthpiece 4b positioned below, with the tube axis oriented vertically.

In this position, the coating liquid of the ultraviolet absorbing substance is sprayed from the shower nozzle 20, as shown in FIGS. 1(A) and 2(A), respectively. The coating liquid sprayed onto the outer surface of the valve 1 flows down along the outer surface of the valve 1.

In this case, by moving the valve 1 in the vertical direction, the coating liquid is applied to the entire outer surface of the valve 1, and by rotating the valve 1, the coating liquid is also applied to the entire outer surface of the valve 1. You can do it like this.

When the coating liquid is applied to the outer surface of the bulb 1 in this way, as shown in FIG. 1(B) and FIG. 2(B), the bulb 1
Keep the tube axis vertical and allow it to dry naturally at room temperature. Note that this natural drying time may be about 30 seconds, although it depends on the room temperature.

Next, as shown in FIG. 1(C) and FIG. 2(C), the valve 1 is turned upside down so that the other cap 4b is located at the top and the one cap 4a is located at the bottom. Then, support the tube so that its axis is vertical.

In this posture, the coating liquid of the ultraviolet absorbing substance is sprayed from the shower nozzle 21.

In this case as well, by moving the valve 1 in the vertical direction, the coating liquid is applied to the entire outer surface of the valve 1, and by rotating the valve 1, the coating liquid is also applied to the entire outer surface of the bulb 1. You can.

When the coating liquid is applied to the outer surface of the bulb 1 in this way, as shown in FIG. 1(D) and FIG. 2(D), the bulb 1
Keep the tube axis vertical and allow it to dry naturally at room temperature. Note that this natural drying time may be about 30 seconds, although it also depends on the room temperature.

When the coating liquid of the ultraviolet absorbing substance is applied to the outer surface of the bulb 1 in this manner, it is heated in a heating furnace or the like to bake the coating film.

This firing may be performed at 100° C. for about 10 minutes.

In this way, a coating 6 containing an ultraviolet absorbing substance for preventing color fading is formed on the outer surface of the bulb 1.

The film thickness of this coating 6 is about 2jm.

According to this coating method, the valve 1 is held in a position where ifldl is vertical, and the coating liquid applied to the outer surface is allowed to dry naturally, so that the coating liquid drips due to gravity during drying, and therefore the valve 1 is held in a vertical position. The film thickness at the top becomes thinner and the film thickness at the bottom becomes thicker.

However, the valve 1 is then turned upside down to keep the tube axis in a vertical position, and the coating liquid reapplied on top of the above coating liquid is allowed to dry naturally. The film thickness at the top of the valve becomes thinner and the film thickness at the bottom becomes thicker.

Therefore, by applying and drying twice before and after, the difference in film thickness between the upper and lower parts of the bulb is reduced, that is, the difference in film thickness along the tube axis direction is reduced.

In addition, in the case of the above example, the difference between the maximum film thickness and the minimum film thickness is
It is about 0.2 #1, and the unevenness of the coating has been eliminated.

Therefore, the quality is improved, the defect rate is reduced,
Yield is also improved.

In the above embodiment, as shown in FIGS. 1 and 2, a plurality of shower nozzles 20 and 21 were used to spray the coating liquid onto the outer surface of the valve. The application method may be a brushing method, a spray method, a dipping method, a curtain flow method, or the like.

When a coating liquid is applied to the outer surface of a bulb by a dipping method or the like, the bulb is immersed in a tank of the coating liquid, so the direction and posture of the bulb during immersion may be horizontal. That is, the present invention is applied to the outer surface of the valve. The position of the valve is not a problem when applying cloth liquid, but the position of the valve is a problem when drying the applied liquid.

Therefore, even when a spray coating method is adopted, the coating solution is not limited to being applied after reversing the valve, as shown in Fig. 1 (C) and Fig. 2 (C), respectively. , the bulb may be inverted after applying the coating liquid.

Further, the coating liquid of the ultraviolet absorbing substance of the present invention is not limited to the above-mentioned embodiments, and a liquid in which ultraviolet absorbing substance fine powder consisting of titanium oxide, zinc oxide, and cesium oxide and a binder are mixed and dispersed in a solvent may be used. .

In this case, the fine powder of the ultraviolet absorbing substance made of titanium oxide, zinc oxide, and cesium oxide has a particle size of 0. It is preferably less than IIIl.

In addition, as a binder, it is difficult to deteriorate due to ultraviolet rays,
It is required to have excellent visible light transmittance, adhesion to glass, film strength, film formability, and drying properties. Resin; Acrylic resin; Fluorine resin; Silicone resin; Alkali silicate such as sodium silicate; Inorganic colloid such as silica sol and alumina sol; Alkyl silicate such as tetraethoxysilane; Phosphate such as aluminum phosphate; Metal alkoxide, Examples include organometallic compounds such as aluminum chelate and tin acetate.

Furthermore, the solvent may be any solvent as long as it dissolves the binder, but the boiling point must be 6 to enable drying at low temperatures.
The temperature is preferably about 0 to 200°C, and examples include aromatic hydrocarbons such as xylene and toluene; alcohols such as n-butanol; esters such as butyl acetate; ketones such as methyl isobutyl ketone; and glycol ethers such as ethyl cellosol. : Saturated hydrocarbons such as n-hexane, ligroin, mineral spirits, etc.

Note that this invention is not limited to straight-tube fluorescent lamps, but may also be ring-shaped fluorescent lamps, and is not limited to hot cathode fluorescent lamps but also cold cathode fluorescent lamps. It is also possible to implement

[Effects of the Invention] As explained above, according to the present invention, the coating liquid applied to the outer surface of the bulb flows downward due to gravity during the process of drying the bulb while holding the bulb in a vertical position. However, the film thickness on the lower side becomes thicker, and the coating liquid applied to the outer surface of the bulb again increases during the process of drying the bulb by holding it in an upside-down position with the tube axis perpendicular to the above-mentioned position. The film thickness at the bottom of the opposite end becomes thicker,
Therefore, the film thickness can be made substantially uniform as a whole.

This eliminates unevenness in film thickness and improves quality.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and are shown in FIGS.
D) is a plan view showing the order of work steps, and Figures 2 (A) to (
D) is a front view showing the order of work steps, FIG. 3 is a perspective view of the straight tube fluorescent lamp, and FIG. 4 is a sectional view thereof. DESCRIPTION OF SYMBOLS 1... Bulb, 2... Fluorescent coating, 3... Electrode, 4 a s 4 b... Base, 6... Ultraviolet absorption coating for preventing fading, 20, 21... Shower nozzle , 22, 23...Chuck.

Claims (1)

[Scope of Claims] A method for manufacturing an ultraviolet suppressing lamp in which a coating containing an ultraviolet absorbing substance consisting of at least one of titanium oxide, zinc oxide, and cerium oxide is formed on the outer surface of the bulb, comprising: The above coating liquid containing the ultraviolet absorbing substance is applied to the bulb, the tube axis is held vertically, and the above coating liquid is dried. Next, the above coating liquid is applied to the outer surface of the bulb again. A method for manufacturing an ultraviolet suppressing lamp, characterized in that the coating liquid is dried by holding the bulb in an orientation in which the tube axis is perpendicular, with the bulb turned upside down from the above-mentioned orientation.