JPS6337458B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a straight or annular fluorescent lamp having two phosphor layers partially laminated on the inner wall of a glass tube, and in particular to high illuminance or high illuminance and high color rendering of these lamps. The invention relates to a fluorescent lamp. A typical fluorescent lamp has a single phosphor coated to a substantially uniform thickness on the inside wall of a glass tube. In such a conventional fluorescent lamp, a substantially uniform luminous flux distribution is obtained in the radial direction from the center of the glass tube. However, in practice, the light beam in the main irradiation direction, which is a specific radial direction from the center of the glass tube, is mainly used.
Reflection type fluorescent lamps have been proposed as fluorescent lamps for this purpose. This is a method in which a dedicated reflective coating such as phosphor or titanium oxide is provided on the inner wall of the glass tube on the side opposite to the main irradiation direction of the fluorescent lamp, and a phosphor coating is further formed on the inner surface. be. However, since this type of fluorescent lamp uses only one type of phosphor, it is possible to achieve high illuminance to some extent, but it is impossible to satisfy both high color rendering properties and high illuminance. moreover,
In this fluorescent lamp, a phosphor coating or a special reflective coating is applied, dried, and then baked at high temperature to completely remove binders such as organic solvents before the next phosphor coating process is performed. , their manufacture requires a lot of manpower and man-hours, and there are manufacturing problems such as poor mass production. In addition to the above-mentioned reflective fluorescent lamps, fluorescent lamps have been proposed in which fluorescent materials having different emission spectra are stacked to achieve high color rendering properties. However, in this fluorescent lamp, different types of phosphor layers are applied over the entire inner wall of the glass tube, so although it is effective in improving color rendering, the luminous flux radiant intensity distribution is The drawback is that it is not possible to increase the illuminance in the main irradiation direction because the illumination is uniform. That is, as mentioned above, conventional reflective fluorescent lamps have a complicated manufacturing process and have poor color rendering properties.On the other hand, conventional ordinary fluorescent lamps, which have excellent color rendering properties, have a low luminous flux in the main irradiation direction. It had the following drawback. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a straight or annular reflection type fluorescent lamp which has a simple manufacturing process and has high illuminance or high illuminance and high color rendering properties in the main irradiation direction. be. In order to achieve the above object, in the present invention, a phosphor layer provided on the inner wall of the glass tube is provided. The present invention is characterized in that it is constituted by a phosphor layer having the same or different emission spectrum from the above-mentioned phosphor layer. By configuring the phosphor layer in this way, it is possible to omit the firing step of the phosphor initially deposited on the inner wall of the glass tube, and at the same time, it is possible to significantly improve the illuminance in the main irradiation direction, or the illuminance and color rendering properties. was completed. Hereinafter, the present invention will be described in detail using the annular fluorescent lamp FCL-30 as an example using drawings and tables. FIG. 1 is a cross-sectional view of a conventional annular fluorescent lamp for reference. As is clear from the drawings, in a conventional annular fluorescent lamp, a single layer of fluorescent material 2 having a specific emission spectrum is coated on the inner wall of a glass tube 1 almost uniformly over the entire circumferential direction. On the other hand, the reflective annular fluorescent lamp according to the present invention has a phosphor layer 2 having a specific emission spectrum on the entire circumferential surface of the inner wall of the glass tube 1, as shown in the cross-sectional view of FIG. On top of that, a phosphor layer 3 having an emission spectrum that is the same as or different from that of the phosphor in the phosphor layer 2 is coated in a region excluding the aperture angle α in the circumferential direction. There is. How to take the aperture angle α is that the aperture is on the vertical axis D-
Open at equal angles of α/2 to the left and right with D' as the center. The main irradiation direction is the direction facing the phosphor layer 3 (vertically downward) as shown by arrow R. The difference between the cross-sectional structure of a conventional reflective fluorescent lamp (not shown) using a phosphor as a reflective coating and the cross-sectional structure of the reflective fluorescent lamp according to the present invention shown in FIG. The point is that layer 2 and layer 3 are exchanged. In other words, the conventional lamp has a cross-sectional structure in which layer 3 is first provided in a region excluding the aperture angle α, and layer 2 is provided over the entire surface. In the present invention, the phosphors used in the phosphor layers 2 and 3 include:
There are phosphors of white color, daylight color, warm white color shown in JISZ 9112 (chromaticity classification of fluorescent lamps), and improved color rendering thereof, such as pure natural white color.
These phosphors have emission peaks in the vicinity of 480 nm and 580 nm, and contain manganese, antimony-activated calcium halophosphate, tin-activated strontium/magnesium orthophosphate, manganese-activated zinc silicate, and manganese-activated zinc silicate. It is a mixture of calcium halophosphate and an appropriate amount of phosphor such as active fluorogelmate. Furthermore, new phosphors that are activated with rare earth elements and synthesize a plurality of emission line spectra have recently come into use as pure natural white phosphors. As described above, the phosphors used in the present invention are phosphors conventionally used for general illumination, either singly or in combination. The effects of the lamp according to the present invention will be described below. FIG. 3 shows the luminous flux radiation intensity distribution on a plane including the glass tube cross sections C-C' and D-D' in FIGS. 1 and 2. FIG. In the light distribution curve A of a conventional general type fluorescent lamp, the radiation intensity in any direction with respect to the center 4 of the tube cross section is substantially equal, whereas in the reflection type fluorescent lamp according to the present invention, the radiation intensity is substantially equal. The light distribution curve B has the advantage that the main irradiation direction R has higher illuminance. This is because the phosphor film on the inner wall of the glass tube is thick in areas other than the main irradiation direction, so the emitted light flux from the phosphor surface is reflected inward, and the phosphor film is thinner in the main irradiation direction. This is because it passes through and is radiated. Incidentally, the light distribution curve of a conventional reflective fluorescent lamp also shows a tendency almost similar to curve B shown in FIG. However, there are significant differences between the manufacturing processes of conventional reflective fluorescent lamps using phosphors as reflective coatings and reflective fluorescent lamps according to the present invention. In other words, in a conventional reflection type fluorescent lamp, the phosphor is coated on the inner surface of the glass tube 1 in an area other than the aperture angle α, and then the phosphor is applied to the entire inner surface of the glass tube 1 through a drying and baking process. It is completed through coating, drying, and firing processes. On the other hand, in the reflection type fluorescent lamp of the present invention having the cross-sectional structure shown in FIG. A fluorescent lamp is completed by coating a part of the inner surface of the glass tube 1 with a fluorescent substance without going through any steps, and after drying, the fluorescent layers 2 and 3 are simultaneously fired in a firing furnace. That is, there is a major difference between the manufacturing process of the conventional reflection type fluorescent lamp and that of the reflection type fluorescent lamp according to the present invention in the presence or absence of a step of firing the phosphor coated first. This brings great advantages in terms of manufacturing equipment and manufacturing process time.
The reason why this firing step can be omitted is due to the difference in appearance. In other words, if the first firing step is omitted in the conventional reflective fluorescent lamp manufacturing process, the first applied phosphor will dissolve into the next applied phosphor. As a result, the opening end of the phosphor that is first applied sag, spoiling the appearance. However, in the manufacturing process of a reflective fluorescent lamp having a cross-sectional structure according to the present invention, even if the firing step of the phosphor layer 2 is omitted, sagging occurs at the open end of the phosphor layer 3 to be applied next. The result is an appearance with very sharp contours. Based on the above experimental results, Table 1 shows the performance when phosphors having the same or different emission spectra are combined. The fluorescent lamp under test is JIS-
In C-7601 (fluorescent lamp for general lighting)
It is FCL-30. No.-1 in Table 1 is the conventional normal FCL-30W, and the relative illuminance at this time is
100, and the average color rendering index is 64. No.―

[Table] 2 is a reflection type fluorescent lamp according to the present invention, in which the same white phosphor is applied twice.The second application is applied only to about half of the tube cross section (upper half), and the remaining half is coated with the same white phosphor twice. The first layer was left as is. Incidentally, one side of the second layer of phosphor shown in Table 1 was coated using the same coating method as in the case of No.-2. In the case of No.-2, the relative illumination increases by 30%, resulting in one profit.
However, in order to satisfy the two contradictory requirements of illuminance and color rendering, the combination of white phosphors (No. 2) has poor color rendering, and the combination of pure natural white phosphors (No. 2) has poor color rendering. In 3), the illuminance is poor. However, the reflection type fluorescent lamps No.-4 to No.-7 according to the present invention have the advantage of significantly improving color rendering properties while maintaining illuminance higher than that of current lamps by combining conventionally existing phosphors. is obtained.
Conversely, when the first layer of phosphor, i.e., the inner wall of the glass tube, is coated on only one side, and then the second layer is coated on the entire surface, the performance as shown in Nos. 8 and 9 is obtained. There is almost no effect of the phosphor in the first layer, and the benefit of simultaneous improvement in color rendering and illuminance due to the combination of different types of phosphors cannot be obtained. Next, as for the aperture angle α in the non-fluorescent coating area of the second layer, it is determined that the aperture angle α is 120° to
240° is appropriate, and therefore, the coating range of the second layer of fluorescent material is also 120° to 240°, that is, the range of 1/3 to 2/3 of the circumference of the inner wall of the glass tube in the cross section of the completed fluorescent lamp. It is preferable to do so. It is appropriate that the coating amount of the phosphor be 1.5 to 5.0 mg/cm ² for both the first layer and the second layer. The reason for this is that if the coating amount is less than 1.5mg/cm ² , the luminous flux will deteriorate significantly, and if it exceeds 5.0mg/cm ² , the illuminance will begin to saturate, which is wasteful, and furthermore, the film strength will weaken and the film will peel off. This is undesirable as it tends to occur. Since the coating method is a conventionally well-known method, its explanation will be omitted. In this way, the manufacturing process is greatly simplified by the present invention, and by combining conventionally used phosphors, it is possible to achieve both brightness, or illuminance, as well as illuminance and color rendering properties. Therefore, it is highly versatile and highly practical. In the embodiments, the description has focused on the ring-shaped fluorescent lamp FCL-30, but it goes without saying that the present invention can also be applied to other ring-shaped fluorescent lamps and straight tube fluorescent lamps.

[Brief explanation of the drawing]

Figure 1 is a partial cross-sectional view of a conventional annular fluorescent lamp.
FIG. 2 is a partial sectional view of the annular fluorescent lamp according to the present invention, FIG. 3 is a diagram showing the light distribution curve of the annular fluorescent lamp shown in FIGS. 1 and 2, and FIG. 4 is a diagram showing the light distribution curve of the annular fluorescent lamp shown in FIG. 2 is a graph showing the relationship between the aperture angle α and the relative illuminance of an annular fluorescent lamp. 1... Glass tube, 2... First phosphor layer, 3... Second
Phosphor layer, α...Aperture angle, R...Main irradiation direction.

Claims (1)

[Scope of Claims] 1. A glass tube having electrodes at both ends and filled with appropriate amounts of mercury and rare gas, and a first phosphor layer provided on the entire inner wall of the glass tube. ,
A fluorescent lamp comprising: a second phosphor layer provided on the first phosphor layer along the axial direction of the glass tube, leaving a certain opening angle. . 2. Claim No. 2, characterized in that the phosphor constituting the first phosphor layer has the same emission spectrum as the phosphor constituting the second phosphor layer. Fluorescent lamp according to item 1. 3. Claim 1, characterized in that the phosphor constituting the first phosphor layer has an emission spectrum different from that of the phosphor constituting the second phosphor layer. Fluorescent lamp as described in Section 2. 4. The fluorescent lamp according to any one of claims 1 to 3, wherein the opening angle is in the range of 120 to 240 degrees. 5. According to any one of claims 1 to 4, wherein the first and second phosphor layers each have a phosphor coating amount of 1.5 to 5.0 mg/cm ² . Fluorescent lamp as described. 6. The fluorescent lamp according to any one of claims 1 to 5, wherein the glass tube has a linear shape. 7. The fluorescent lamp according to any one of claims 1 to 5, wherein the glass tube has a curved shape.