JPS6358756A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To substantially improve initial luminous flux and better luminous flux maintenance factor by making a smooth transparent coating of cerium oxide on the inner surface of a glass bulb and maintaining optimum thickness thereof. CONSTITUTION:A transparent cerium oxide coating with adhesive amount in the range of 5 to 200mug/cm<2> is formed on the inner surfaces of glass bulbs 11 through 14. By this arrangement, ultraviolet rays passing through phosphor coatings reach the transparent cerium oxide coatings on the glass bulbs 11 through 14 with a part of which is effectively reflected contributing to luminance while still a part of which is absorbed into the coating thus checking the ultraviolet rays from reaching the glass bulbs. As the result, initial luminous flux of a fluorescent lamp is improved substantially, and luminous flux maintenance factor is also improved at the same time.

Description

[Detailed description of the invention] Industrial applications The present invention relates to fluorescent lamps.

Conventional technology Conventionally, in fluorescent lamps, the inner surface of the glass bulb and the phosphor coating were used to improve the luminous flux maintenance rate and to prevent fading and deterioration of paintings, antiques, etc. due to ultraviolet rays emitted from the lamp. It is known that an oxide film of titanium oxide, alumina, etc. is formed in between.

Such an oxide film contributes to light emission by reflecting the ultraviolet rays that have passed through the phosphor coating and returns them to the phosphor coating, and also prevents the glass from darkening by suppressing the ultraviolet rays from reaching the glass bulb. It is.

Problems to be Solved by the Invention However, in such conventional fluorescent lamps, the oxide coating, typified by some alumina, which has increased UV reflectance through surface reflection of the coating, generally has a rough surface and low visible light transmittance. On the other hand, a transparent titanium oxide coating that aims to improve UV reflectance through thin film interference cannot sufficiently contribute to improving luminous flux due to its high UV absorption. was there.

The present invention was made to solve these problems.Titanium oxide does not absorb ultraviolet rays, but cerium oxide is made into a transparent and smooth film that absorbs ultraviolet rays by maintaining its optimal thickness. The present invention provides a fluorescent lamp that has increased reflectance, significantly improved initial luminous flux, and improved luminous flux maintenance factor.

Means for Solving the Problem In order to solve this problem, the present invention applies a transparent cerium oxide coating to the inner surface of the glass bulb in an amount of 5 to 200 μg.
/ ant, and a phosphor film is formed on the cerium oxide film to form a fluorescent lamp.

With this configuration, the ultraviolet rays that have passed through the phosphor coating reach the transparent cerium oxide coating on the glass bulb, where some of it is efficiently reflected and contributes to light emission, and some of it is absorbed by the coating. This prevents ultraviolet rays from reaching the glass bulb. As a result, the initial luminous flux of the fluorescent lamp is significantly improved and the luminous flux maintenance rate is also improved.

Note that if the amount of the coating is less than 5 μg/cd, it will not be possible to obtain a high ultraviolet reflectance (and the ultraviolet absorbency will also be low, making it impossible to suppress ultraviolet rays from reaching the glass bulb.

On the other hand, if the amount of adhesion exceeds 200 μg/cJ, the ultraviolet absorbency increases, making it impossible to obtain a high ultraviolet reflectance, and the visible light transmittance also decreases, resulting in a decrease in luminous flux.

Example Embodiments of the present invention will be described below with reference to the drawings.

First, the transmittance of the cerium oxide coating (I) and titanium oxide coating, which was deposited at approximately 20 μg/ci on a flat quartz glass plate, was measured using the third method.
As shown in the figure. In the figure, curve 6 shows the transmittance of the base quartz glass, curve 7 shows the transmittance of glass with cerium oxide attached, and curve 8 shows the transmittance of glass with titanium oxide attached. As is clear from this figure, the cerium oxide coating has a higher ultraviolet transmittance than the titanium oxide coating.

On the other hand, the relative spectral reflectance of the cerium oxide film and the titanium oxide film, which were attached to the base glass at a concentration of about 20 μg/ci on a flat soda-lime glass whose back surface was frosted, was calculated as follows.
As shown in the figure. In the figure, curve 9 shows the relative spectral reflectance of the cerium oxide film, and curve 10 shows the relative spectral reflectance of the titanium oxide film. As is clear from this figure, the cerium oxide coating and the titanium oxide coating exhibit higher ultraviolet reflectance than the titanium oxide coating.

Based on these results, a cerium oxide film was applied to a fluorescent lamp and evaluated.

An ethyl alcohol solution of cerium complex of acetylacetone was used as a starting material, and the inner diameter was 15 mm, which had been cleaned in advance.
Apply the coating to the inner surface of the glass bulb in various amounts, 1
It was dried at 20°C for 5 minutes.

Further, it was heated and baked at 550° C. for 10 minutes to form a smooth transparent cerium oxide film. A three-wavelength rare earth phosphor (BaMgAe+6
027: Eu, LaPo4: Ce.

After applying 1.4 g of 3+ Tb, Y2O3:ELI), drying and firing, a 27 Watt type fluorescent lamp having two bridge connections as shown in FIG. 5 was prepared and tested using a conventional method.

In FIG. 5, reference numerals 11 to 14 indicate glass bulbs, and an electrode (not shown) is provided at one end of the glass bulbs 11 and 12. 15 is a first bridge, 16 is a second bridge, and 17 is a cap.

At the same time, a fluorescent lamp in which a transparent titanium oxide film made of the same starting material was applied instead of the transparent cerium oxide film was fabricated and tested in the same manner.

The luminous flux values of these fluorescent lamps after being lit for 100 hours are shown in FIG. In the figure, curve 1 shows the lamp luminous flux of a fluorescent lamp having a cerium oxide film according to the present invention, and curve 2 shows the lamp luminous flux of a conventional fluorescent lamp having a titanium oxide film. As is clear from this figure, the fluorescent lamp according to the present invention can obtain a luminous flux equivalent to or higher than the luminous flux level obtained by a lamp with a titanium oxide coating applied in a coating amount of 5 to 200 μg/cj, and especially when the coating amount is 20 μg/cj. /c
The effect was noticeable around ++f, and the 100-hour luminous flux of the fluorescent lamp according to the present invention was improved by 4.4% compared to the conventional fluorescent lamp.

Additionally, in addition to a fluorescent lamp with a transparent cerium oxide coating with a coating amount of approximately 20 μg/cJ and a fluorescent lamp with a transparent titanium oxide coating with the same coating amount, three fluorescent lamps with no oxide coating were added. 1 type of fluorescent lamp
Figure 2 shows the luminous flux maintenance weight after 000 hours of lighting. In the figure,
Curve 3 shows the lumen maintenance factor of a lamp with a cerium oxide coating according to the present invention, curve 4 shows the lumen maintenance factor of a lamp with a conventional titanium oxide coating, and curve 5 shows the lumen maintenance factor of a lamp without an oxide coating. . As is clear from this figure, the 1000-hour luminous flux maintenance rates of the lamps with cerium oxide coating and titanium oxide coating are 92% and 99%, respectively.
It can be seen that the luminous flux maintenance rate of 0% is significantly higher than that of a lamp without an oxide coating, and that the cerium oxide coating is also superior to the titanium oxide coating in terms of luminous flux maintenance rate.

The relationship between the amount of cerium oxide deposited and the 100-hour luminous flux is the same for other fluorescent lamps, and it is possible to improve the lamp luminous flux within the range of the amount of cerium oxide deposited from 5 to 200 μg/cj.

As described in detail, the present invention forms a transparent cerium oxide film on the inner surface of a glass bulb with a coating amount of 5 to 200 μg/cd, and forms a phosphor film on top of the transparent cerium oxide film, thereby increasing the initial luminous flux. This makes it possible to provide a fluorescent lamp that has excellent effects such as greatly improved luminous flux retention.

[Brief explanation of drawings]

Figure 1 is a curve diagram showing the lamp luminous flux after 100 hours of operation when different amounts of cerium oxide film and titanium oxide film are applied to fluorescent lamps. Figure 2 is a lamp with cerium oxide film and a lamp with titanium oxide film applied. A curve diagram showing the luminous flux maintenance factor of a lamp and a lamp without an oxide film applied. Figure 3 is a curve diagram showing the transmittance of a cerium oxide film and a titanium oxide film deposited on a flat quartz glass. FIG. 5 is a curve diagram showing the relative spectral reflectance of a cerium oxide film and a titanium oxide film deposited on a frosted flat soda-lime glass with respect to the base glass. FIG. 5 is a perspective view of a fluorescent lamp according to an embodiment of the present invention. 11-14...Glass bulb, 17...
・Case. Name of agent Patent attorney Toshio Nakao and one other person lσθ Time end (mu) 8 Figure 2, 41. r1 time (time) Figure 3 -k (nrn) Figure 4 -k (nrn) Figure 5

Claims (1)

[Claims] Amount of transparent cerium oxide film deposited on the inner surface of the glass bulb is 5.
A fluorescent lamp characterized in that a phosphor film is formed on the cerium oxide film in a range of ˜200 μg/cm^2.