JPH0565980B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a fluorescent lamp, and particularly relates to improving the luminous flux deterioration characteristics of a fluorescent lamp. [Prior Art] Various studies have been conducted on improving the luminous flux deterioration characteristics of conventional fluorescent lamps, and the improvement effect of a protective film is particularly remarkable. A protective film is a metal oxide film such as alumina provided on the inner surface of a glass bulb, which separates the glass bulb from the phosphor layer and also separates the discharge space, thereby preventing sodium, etc. in the glass. This effectively suppresses precipitation on the phosphor layer and reaction with mercury. The required condition here is that the coating effect of metal oxides such as alumina on the glass be sufficient, and a dense film made of fine particle powder is being considered, and alumina with one particle of about 20 millimicrons is being used. was. However, even with the use of the above methods, luminous flux deterioration of fluorescent lamps cannot be completely prevented, and further improvement of the luminous flux deterioration characteristics is desired. If an intermediate separation layer (protective film) such as alumina is provided, the luminous flux deterioration characteristics will be greatly improved compared to when it is not provided, but if the thickness of the protective film is increased to further improve the phosphor layer film strength. decreases significantly. Therefore, there is a limit to the thickness of the protective film. In order to further increase the thickness of the protective film, special measures such as adding an adhesion strength increasing agent to the protective film as disclosed in JP-A-60-105160 were required. Therefore, through a series of experiments, the inventors discovered that alumina, which could not be used as a protective film beyond a certain thickness due to problems such as a decrease in the strength of the phosphor layer, had insufficient coating effect. We thought of improving the luminous flux deterioration characteristics of fluorescent lamps by increasing the separation effect between the discharge space and the glass by mixing it with glass, and confirmed this effect through experiments. Further, at this time, when the amount of alumina mixed was 60% or less, there was no problem with the strength of the phosphor layer. The results are shown in FIG. [Problems to be solved by the invention] However, even in the above improvement means, the second
As can be seen from the results in the figure, although the recessive luminous flux characteristics were improved, there was a problem in that the initial luminous flux value decreased due to the alumina mixture. The present invention was made to solve these problems, and an object of the present invention is to provide a fluorescent lamp that can improve the luminous flux deterioration characteristics and approximate the initial luminous flux value to that without alumina contamination. [Means for Solving the Problems] In the fluorescent lamp according to the present invention, alumina is mixed into the phosphor layer, and the proportion of the mixed alumina increases toward the bulb side. [Function] In this invention, alumina, which cannot be attached as a protective film at a thickness exceeding a certain level due to problems such as a decrease in the strength of the phosphor layer and the coating effect is insufficient, is also used in the phosphor layer. The luminous flux deterioration characteristics of the fluorescent lamp can be improved by mixing the glass and increasing the separation effect between the discharge space and the glass. Here, even if alumina is used as a protective film at a thickness that is at the upper limit of the strength of the phosphor layer, it is possible for it to be further mixed into the phosphor layer. The strength of the phosphor layer does not decrease. Furthermore, by concentrating alumina in the phosphor layer on the bulb side, where the contribution to visible light conversion is relatively low, a decrease in the initial luminous flux value due to alumina contamination is suppressed. [Embodiment] FIG. 1 is a sectional view of a main part showing an embodiment of the present invention. That is, a protective film 4 is provided on the inner surface of the bulb 3, and two phosphor layers are formed on the protective film 4. A predetermined amount of alumina is dispersed in this phosphor layer. Regarding a fluorescent lamp having a phosphor layer and structure as shown in FIG. 1, an experiment was conducted in which the amount of alumina 2 mixed into the phosphor layer was varied. The particle size distribution of alumina 2 mixed in the phosphor layer is
Figure 4 shows its impurity components. First, the experiment was conducted using a circular fluorescent lamp (FCL30) type as a lamp, a three-wavelength emission type rare earth phosphor as a phosphor, and alumina 2 with an average particle size of 20 mμ as a protective film 4. The dispersed solution with a concentration of 0.5% was applied to the inner surface of the valve 8 and dried. As a result, the values shown in Table 1 and Figures 5a to 5d were obtained.

【table】

〔Effect of the invention〕

As explained above, this invention has the effect of suppressing the decrease in the initial luminous flux value due to this mixing and improving the luminous flux deterioration characteristics by incorporating alumina into the phosphor layer near the bulb at a high concentration. be.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between the amount of alumina mixed in and the total luminous flux, and Fig. 3 shows the particle size distribution of alumina mixed in the phosphor layer. Figure 4 shows the impurity components, and Figure 5a shows the amount of alumina mixed in the second phosphor layer of the two phosphor layers, when the amount of alumina mixed in is 0%. Similarly, 5b shows the relationship between the amount of alumina mixed into the phosphor layer and the initial luminous flux.
FIG. 7 is a characteristic diagram showing the relationship between the amount of alumina mixed into the second phosphor layer and the initial luminous flux when the amount of alumina mixed into the second phosphor layer is 40%.
Figure 5c also shows the relationship between lighting time and total luminous flux when the amount of alumina mixed in the second phosphor layer is 0%, and Figure 5d shows the relationship between the lighting time and the total luminous flux when the amount of alumina mixed in the first layer is 40%. It is a characteristic diagram which shows the relationship between lighting time and total luminous flux when it does. In the figure, 1 is a phosphor, 2 is alumina, 3 is a bulb, and 4 is a protective film.

Claims (1)

[Scope of Claims] 1. A fluorescent lamp characterized in that alumina is mixed into a phosphor layer provided on the inner surface of the bulb, and the proportion of alumina mixed increases as it approaches the bulb side. 2. When the phosphor layer is made up of multiple layers, the proportion of alumina mixed in the phosphor layer on the side closer to the bulb side is higher than the phosphor layer on the side closer to the discharge path, as described in claim 1. fluorescent lamp. 3. The fluorescent lamp according to claim 2, wherein the amount of alumina mixed in the phosphor layer on the bulb side is 5% or more of the weight of the phosphor.