JPH03295147A - Tubular bulb - Google Patents

Abstract

PURPOSE:To prevent the discoloration of displayed articles due to ultraviolet rays by mixing a ultraviolet ray depressant directly into a fluororesin film formed on the outer surface of a glass bulb. CONSTITUTION:A light emitting tube 5 made of quartz glass is stored in the outer tube bulb 1 of a metal halide lamp, and electrodes 6, 6 are sealed inside both ends of the light emitting tube 5. A fluororesin film 12 is formed over the whole outer surface of the outer tube glass 1. A ultraviolet ray depressant made of at least one kind of titanium oxide and zinc oxide is mixed into the fluororesin film 12, thus the ultraviolet ray depressant restricts the permeation of ultraviolet rays. When this lamp is used for the illumination of displayed articles at a shop, the emission of ultraviolet rays from this lamp can be reduced, and the discoloration of the displayed articles due to ultraviolet rays can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a glass bulb having an anti-fly (explosion-proof) film made of fluororesin formed on the outer surface of the bulb.

(Prior Art) High-intensity discharge lamps (HID) have recently become more compact and are increasingly being used indoors, such as in stores.

When a high-intensity discharge lamp is used indoors, particularly in a store, it is dangerous that glass fragments may fall if the outer bulb were to break.

In other words, a metal vapor discharge lamp is a two-piece lamp with an arc tube housed in an outer bulb.
It has a double tube structure, and is used by attaching the cap attached to the end of the outer tube to the socket of the instrument.

In this case, the lamp is generally lit in a vertical position with the base facing upward.

In such discharge lamps, if the outer bulb were to be damaged due to an external shock, etc., or if the luminous tube burst, there is a risk of glass fragments scattering and falling, especially in stores. It is very dangerous if used indoors.

In order to prevent such problems, a method has been adopted in which the outer surface of the outer tube is coated with a fluororesin to form a fly-proof coating.

If the outer surface of the outer tube is coated with a fluororesin, this fluororesin coating will improve the mechanical strength of the outer tube glass and prevent breakage, and even if the outer tube glass breaks, it will prevent glass fragments from scattering and It can prevent you from falling.

However, when discharge lamps are used to illuminate products on display in the above-mentioned stores, etc., the ultraviolet rays emitted from the lamps cannot be ignored, and the products on display may fade due to the ultraviolet rays.

In the future, it is thought that the illuminance used to illuminate products in stores will become even higher, and there will be a need to develop lamps that suppress ultraviolet rays.

Conventionally, as such a lamp, Japanese Patent Application Laid-Open No. 64-2185
No. 5 discloses a technique for coating the outer surface of an outer tube glass with an ultraviolet inhibitor.

(Problems to be Solved by the Invention) In the above-mentioned publication, an ultraviolet inhibitor made of titanium oxide is mixed into a primer film as an undercoat material for a fly-proof coating made of a fluororesin.

That is, when forming a fly-proof coating made of fluororesin on the outer surface of the outer tube glass, a brimer film is first formed on the outer surface of the outer tube glass, and a fly-proof coating made of fluororesin is formed on the outer surface of this brimer film. The brimer film is applied as an adhesive to increase the adhesion of the anti-fly coating to the glass.

Conventionally, a powdered ultraviolet inhibitor made of titanium oxide was mixed into this brimer film.

However, when powder such as titanium oxide is mixed in the primer layer, the adhesion function decreases, and the anti-fly coating made of fluororesin tends to peel off. Therefore, it is not possible to mix in a large amount of the ultraviolet ray inhibitor, and the ultraviolet ray inhibitory effect may become insufficient.

Increasing the thickness of the primer layer may be considered to increase the binding strength of the anti-fly coating, but the primer layer itself is colored, and increasing this thickness will reduce the transmission efficiency of visible light due to coloring. There is a problem where the value decreases.

The present invention was developed based on the above circumstances, and it is possible to maintain the explosion-proof performance of a glass bulb without reducing the binding strength of the anti-fly coating, and to suppress the emission of ultraviolet rays to prevent color fading due to ultraviolet rays. We are trying to provide a tube that can.

[Structure of the Invention (Means for Solving the Problems)] The present invention is characterized in that an ultraviolet inhibitor is directly mixed into a fluororesin coating formed on the outer surface of a glass bulb.

(Function) According to the present invention, an ultraviolet inhibitor such as titanium oxide or zinc oxide is directly mixed into the fluororesin film coated on the outside of the primer layer, so that the fluororesin film does not adhere to the primer layer. It becomes difficult to peel off without decreasing its strength.
The explosion-proof performance of the bulb can be maintained to prevent debris from falling, and the ultraviolet inhibitor suppresses the emission of ultraviolet rays to prevent color fading due to ultraviolet rays.

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

The drawings show an example in which the present invention is applied to a 250W metal halide lamp. In the drawings, reference numeral 1 denotes an outer bulb of the metal halide lamp, which is made of hard glass. This outer tube 1 has a bulge in the center, and
It has a small-diameter top part 2 at the lower part of the drawing and a small-diameter neck part 3 at the upper part of the drawing, and is formed in a so-called BT shape.

A cap 4 is fixed to the upper end of the neck portion 3, and is used by being screwed into a socket on an instrument (not shown).

An arc tube 5 made of quartz glass or the like is housed within the outer tube 1, and electrodes 6 are placed inside both ends of the arc tube 5.
6 is sealed. The arc tube 5 is filled with a predetermined amount of mercury, a metal halide such as an iodide of Sc and Na, and a starting rare gas.

Both ends of the arc tube 5 are supported by support wires 8.8 via insulating holders 7.7.

One support wire 8 is locked to the top portion 2 of the outer tube 1 via an elastic body 9, and the other support wire 8 is provided protruding from the stem 10 or welded to the single lead wire 11a. .

One electrode 6 is connected to another lead wire 11b protruding from the stem 10 via a power supply line 12, and the other electrode 6 is connected to the other support wire 8.

The lead wires 11a and 11b are connected to the shell of the base 4 and external terminals.

A coating 12 made of fluororesin is formed over the entire surface of the outer glass tube 1.

In this case, first, a brimer layer 1 is applied to the outer surface of the outer tube glass 1.
3, and an anti-fly coating 12 made of fluororesin is formed on the outside of this brimer layer 13.

The fluororesin coating 12 covers the entire outer surface of the outer tube 16.
It is formed to have a film thickness t of 0 to 150 gm, for example about 100 μm.

This fluororesin coating 12 contains titanium oxide (T i O
2) and an ultraviolet inhibitor consisting of at least one of zinc oxide (ZnO).

In the case of this example, titanium oxide powder and zinc oxide powder each having an average particle diameter d of 0.1 μm or less, for example, about 0.02 to 0.04 mm, are mixed at 50% each, and this is added to the fluororesin by 50% each. 05-10% by weight, specifically 1% by weight
They are mixed at a content ratio M of about 50%.

In this case, the fluororesin is powdered, and the titanium oxide powder and zinc oxide powder are mixed in the above proportions, and this mixed powder is applied to the outer glass tube on which the brimer layer 13 has been formed in advance. The fluororesin coating 12 can be formed by coating the outer surface of the brimer layer 13 of No. 1 using an electrostatic coating method and baking it at, for example, 350°C.

According to such a configuration, since the fluororesin coating 12 is formed on the outer surface of the outer bulb 1, this fluororesin coating 12 improves the mechanical strength of the outer bulb 1 and prevents damage. Furthermore, even if the outer bulb 1 is damaged, glass fragments can be prevented from scattering or falling.

Furthermore, since the fluororesin coating 12 contains an ultraviolet inhibitor consisting of at least one of titanium oxide and zinc oxide, these ultraviolet inhibitors regulate the transmission of ultraviolet rays.

Therefore, when this lamp is used for illuminating products on display in a store or the like, it is possible to reduce the emission of ultraviolet rays from the lamp, and it is possible to prevent the products on display from fading due to ultraviolet rays.

Moreover, since the ultraviolet inhibitor is mixed into the fluororesin coating 12 while avoiding the brimer layer 13, it does not affect the binding force of the brimer layer 13, and the brimer layer 13
No. 3 does not need to be particularly thick, maintains the original adhesive strength, prevents the fluororesin coating 12 from peeling off, and does not reduce visible light transmittance.

Furthermore, since the ultraviolet ray inhibitor is mixed into the fluororesin coating 12, even if the amount of the ultraviolet ray suppressor used is larger than before, the visible light will not be reduced as much as in the past. It can also enhance the effect of suppressing ultraviolet rays.

Next, the results of investigating the content of ultraviolet inhibitor in the fluororesin coating will be explained.

Here, the content of the ultraviolet inhibitor in the fluororesin coating is the content ratio of the ultraviolet inhibitor to the fluororesin powder M (
(% by weight)

Figure 2 shows the content of the ultraviolet inhibitor and wavelengths of 280~
FIG. 3 is a characteristic diagram of the results of measuring the relationship with the radiation amount of ultraviolet rays UVB in the 315 rv region.

The amount of UV radiation is rapidly reduced by adding UV inhibitors.

In the case of the above example, when the mixing ratio of the UV inhibitor to the fluororesin is 1% by weight and the film thickness is 100 μm, the content of the UV inhibitor is ]00 (weight% x μm), and the UV inhibitor is It was confirmed that the ultraviolet emission rate was 1/100 compared to the case of a coating made only of fluororesin without mixing.

It is thought that the effect of suppressing ultraviolet rays, such as preventing discoloration of products, can be obtained by suppressing the amount of ultraviolet rays (UVB) to approximately 1/2.
(jl amount %X ttm) or more, the objective can be achieved.

Moreover, FIG. 3 is a characteristic diagram of the results of measuring the relationship between the content of the ultraviolet inhibitor and the total luminous flux (brightness).

From this experimental result, the luminous flux gradually decreases as the content of the ultraviolet inhibitor increases. This is because the UV inhibitor absorbs visible light, and the content of the UV inhibitor is 30%.
When it exceeds 0 (wt% x pm), the luminous flux decreases to 90% or less, and the coating 12 becomes white in appearance, light diffusion occurs, and the light distribution characteristics deteriorate, making it unsuitable for use as a clear lamp. .

Therefore, the content of the ultraviolet inhibitor is 3oO (wt% x I
Im) The following is desired.

From such a thing, 5≦MXt≦300 It is hoped that the following will be satisfied.

Furthermore, the particle size of the ultraviolet inhibitor powder is such that the average particle size d is 0.
It is desirable that the thickness be 1 μm or less. Average particle size d is 061μ
If it exceeds m, the ultraviolet ray suppression function will be reduced and the visible light transmittance will be reduced.

therefore, d≦0.1μm It is necessary to

Furthermore, the relationship between the particle size of the fluororesin powder and the particle size of the ultraviolet ray inhibitor powder is (particle size of the ultraviolet ray inhibitor powder/particle size of the fluororesin powder)
It is desirable that X100≦1 (%).

If the size ratio of the above powder exceeds 1%, the dispersion of the UV inhibitor in the fluororesin coating will be poor, and the UV inhibitory effect will decrease in some parts of the coating, meaning that the UV inhibitory effect will vary over the entire coating. This may occur.

FIG. 4 is a characteristic diagram showing the results of measuring the relationship between the content of the ultraviolet inhibitor and the tensile strength of the fluororesin coating 12.

From this experimental result, the tensile strength of the fluororesin coating 12 gradually improves as the content of the ultraviolet inhibitor increases. Therefore, if the film thickness is the same, the effect of preventing glass fragments from scattering can be increased by increasing the content of the ultraviolet inhibitor. On the other hand, if the tensile strength is the same as before by mixing an ultraviolet inhibitor, the film thickness can be limited and the amount of fluororesin used, which is expensive, can be saved.

In the above example, equal amounts of titanium oxide and zinc oxide were mixed as ultraviolet suppressants, but if high visible light transmittance is required, zinc oxide alone or a relatively large amount of zinc oxide may be used. If a high inhibitory effect is required, titanium oxide alone or a relatively large amount of titanium oxide may be used.

Further, the ultraviolet suppressant is not limited to titanium oxide and zinc oxide, but may be other ultraviolet suppressants.

Furthermore, the present invention is not limited to metal halide lamps, but can also be applied to other double-tube structure mercury lamps, high-pressure sodium lamps, and other outer tube glass. Furthermore, the same effect can be obtained even when a halogen incandescent lamp is used as a lamp that emits ultraviolet rays.

Effects of the Invention As explained above, according to the present invention, since an ultraviolet inhibitor is mixed into the fluororesin coating, the binding strength of the fluororesin coating is not reduced, and the anti-flying performance of the bulb is improved. It is possible to keep it high to prevent debris from falling, and the ultraviolet inhibitor can suppress the emission of ultraviolet rays to prevent products from fading due to ultraviolet rays.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a front view of a metal halide lamp, Fig. 2 is a characteristic diagram showing the relationship between the content of an ultraviolet inhibitor and the amount of ultraviolet radiation, and Fig. 3 is a diagram showing the relationship between the content of an ultraviolet inhibitor and the amount of ultraviolet radiation. FIG. 4 is a characteristic diagram showing the relationship between the amount and total luminous flux, and FIG. 4 is a characteristic diagram showing the relationship between the content of the ultraviolet inhibitor and the tensile strength of the fluororesin coating. 1... Outer tube, 3... Neck part, 4... Cap, 5...
... Arc tube, 6... Electrode, 8... Support wire,
12... Fluororesin coating, 13... Brimer layer.

Claims (2)

[Claims] (1) A bulb having a coating made of fluororesin formed on the outer surface of the glass bulb, characterized in that an ultraviolet suppressant is mixed into the coating of the fluororesin. (2) The bulb according to claim 1, wherein the ultraviolet suppressant comprises at least one of titanium oxide and zinc oxide.