JPS6342370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a unevenly thick phosphor film for a fluorescent lamp.

In the tube structure of a conventional general fluorescent lamp, as shown in Fig. 1, a phosphor layer 2 is coated on the inner surface of a glass tube 1 with a constant thickness, so that the light distribution characteristic A is as shown in Fig. 2. It has a perfect circular shape with respect to the center. However, in most cases, more light is required to go in one direction (downward) by incorporating it into a lighting fixture and suspending it from the ceiling, so the light from the upper half of the lamp may escape upward, or even Even if the light can be reflected by a fixture or ceiling, it is often wasted due to multiple reflections or poor reflection efficiency. In order to eliminate such defects, reflector type lamps have conventionally existed.
As shown in Fig. 3, its structure is such that a reflective film 3 is formed on the top surface of the glass tube 1 to reflect the upwardly emitted light downward, and its light distribution characteristic B is as shown in Fig. 4. It's getting old. However, in this lamp, the light does not pass through the part where the reflective film 3 is located.
On the other hand, the upper part was too dark, and the ceiling and fixtures gave a gloomy feeling, creating an undesirable atmosphere. In addition, the manufacturing method involves coating the entire surface with the reflective film 3, then removing a portion of it, and then applying the phosphor layer 2. Removing only a portion is troublesome, expensive, and difficult to mass-produce. There were flaws.

Therefore, fluorescent lamps have been proposed that can improve light distribution characteristics and increase usage efficiency. An example is shown in FIG. That is, in this fluorescent lamp, the relationship between the coating layer d 1 on the inner surface 4 on the front side (corresponding to the lower surface side) of the glass tube ₁ and the coating thickness d ₂ on the inner surface 5 on the rear surface side (corresponding to the upper surface side) is d The phosphor layer 6 is applied so that ₁ > d ₂ . As the thickness of the phosphor coating becomes thinner, the ultraviolet absorption rate and hence the visible light (fluorescence) emission rate tend to decrease, so if this is done, the light distribution characteristic C will become as shown in Figure 6. Light is emitted somewhat more towards the upper half than with a reflector type lamp. Since the desired degree can be achieved by changing the coating thickness, the feeling of depression can be suppressed by setting the coating thickness. As an example, we compared the light distribution characteristics of an inverted Fuji-shaped lighting fixture mounted directly on the ceiling with conventional general-use lamps and reflector-type lamps. The result is the 7th
As shown in the figure. In other words, a in the same figure is a general lamp A, and the light distribution characteristic _A1 is that the luminous flux is too large upwards (approximately 30 to 40%), the ceiling surface P becomes too bright, and the actual effective light downwards is too large. decrease. Figure b is reflector type lamp b, and light distribution characteristic _b1 has a small upward luminous flux (several percent), making the ceiling P and fixture Q look dark and gloomy (same even without fixture). ).
The figure c shows the lamp c of the example, and its light distribution characteristic c ₁ allows light to reach the ceiling surface P moderately (10 to 20%).
However, it can be said that most of the light is effectively distributed downward.

In this way, it is possible to efficiently provide light downward while creating a soft light distribution atmosphere throughout the room.

In addition, while this fluorescent lamp can reduce the amount of fluorescent material compared to conventional reflector lamps,
It is possible to obtain the same or higher luminous flux. In particular, when using a high color rendering lamp that uses a special phosphor,
The effect of reducing material costs due to the reduction in the number of phosphors is significant.
In addition, the luminous flux reduction and yellowing of the tube during lighting are generally more severe as the coating thickness of the phosphor is thinner, but in this fluorescent lamp, the parts that can be seen clearly downward are thicker, so the above-mentioned deterioration phenomenon appears to be smaller. The quality effect in actual use is significant.

Further, an indicator mark 7 is provided on the long side of the glass tube 1 of this fluorescent lamp to indicate which side of the phosphor layer 6 is thicker (FIG. 5).

Now, regarding the above-mentioned method of applying uneven thickness of the phosphor film, there is a conventional method in which the glass tube is partially heated by taking advantage of the phenomenon that the coating thickness of the phosphor slurry becomes thinner depending on the temperature of the glass tube ( Jitsukai Showa 54-173584
However, the disadvantage is that the operations such as partial heating of the glass tube and pouring of the slurry under the temperature conditions are complicated, and the productivity is poor.

On the other hand, a device using a method with almost no difference in productivity compared to the conventional method is shown in FIGS. 8 to 10. That is, this manufacturing apparatus applies the phosphor layer 6 to an uneven thickness on the inner surface of the glass tube 1 by a general drooping coating method. The tip of the nozzle 9 that sprays the fluorescent body fluid 8 is circular as shown in FIG. 10, and a large number of small spray holes 10 are formed around it at equal intervals.
In addition, these small holes 10 are controlled to open and close by an on-off valve 11. 12 is an opening/closing valve operating shaft, 13 is a fluorescent body fluid supply container, and 14 is a reservoir. This nozzle 9 is inserted vertically downward at an eccentric position from the upper end of the vertically erected glass tube 1 as shown in FIGS. 8 to 10, and the on-off valve 11 is opened to inject the fluorescent liquid 8. As a result, the ejected fluorescent body fluid 8 comes to adhere to the inner surface of the tube while drawing a parabola, and in this case, since the nozzle 9 is eccentric, the nozzle 9
The inner surface 15 of the tube, which is closer to the inner surface of the tube, is thicker, and the opposite side 16 has a smaller amount of phosphor fluid 8 adhering to it and is formed thinner, resulting in a phosphor layer with uneven thickness as shown in FIG. is formed. In this case, the thickness can be adjusted by adjusting the amount of eccentricity of the nozzle 9. After coating, the inside of the tube is dried, the phosphor fluid is fixed, and the lamp is completed through predetermined processes such as firing the phosphor, sealing the mount, evacuation, and gas filling. This manufacturing apparatus can therefore extremely easily apply the phosphor in uneven thickness without increasing the number of conventional steps.

Moreover, FIGS. 11 to 13 show cases in which uneven thickness is applied by electrostatic coating. In this case, the injection holes 10 of the nozzle 9 are equally spaced (corresponding to FIG. 9), the nozzle 9 is made of metal, and a metal tube 17 is wrapped outside the glass tube 1 to connect the nozzle 9 with the metal. A power source E is connected between the tube 17 and a voltage is applied, and the nozzle 9 is inserted into the glass tube 1 at an eccentric position (at a constant speed) to inject the fluorescent body fluid 8. At this time, the sprayed mist of the fluorescent body fluid 8 is charged and electrostatically adsorbed on the inner surface of the glass tube 1, so compared to the drooping coating method, there is no need for a binder to thicken the fluorescent body fluid 8. By moving the nozzle 9 within the glass tube 1 at a constant speed, the inner surface of the glass tube 1 near the nozzle 9 is thickly coated, and the opposite side is coated thinly. Therefore, the phosphor layer 6 as shown in FIG. 5 can be obtained very easily without changing the number of manufacturing steps.

However, these manufacturing methods require the nozzle to be set at an eccentric position with respect to the glass tube, so it is necessary to adjust the relative positional relationship between the nozzle and the glass tube in conventional manufacturing mass production equipment. However, it has the disadvantage of requiring changes to the equipment.

Therefore, an object of the present invention is to provide a method for forming a phosphor film of uneven thickness for a fluorescent lamp, which can apply conventional equipment as is and coat a phosphor film of uneven thickness without changing productivity. It is to be.

The first embodiment of this invention is shown in FIG.
It is shown in Figure 5. That is, this manufacturing apparatus uses a drooping coating method, and the small injection hole 10' of the nozzle 9 is
The nozzles 9 are arranged at equal intervals, with more in one direction and fewer in the opposite direction, and the nozzle 9 is positioned over the center of the glass tube 1. in this case,
Since the flow rate of the fluorescent fluid coming out of the small injection holes 10' is constant, the more small injection holes 10' there are, the more the fluorescent fluid will be ejected in that direction. As a result, it is possible to form a luminescent layer with uneven thickness as shown in FIG. The coating layer in this case is determined by the uneven density of the injection holes 10'. Other details are the same as in FIGS. 8 to 10. Therefore, according to this method, the only difference from the conventional method is the nozzle 9, and by simply replacing the nozzle 9, the conventional equipment can be used as is, and there is no change in productivity.

A second embodiment is shown in FIGS. 16 to 18. That is, this manufacturing apparatus is similar to the method shown in FIGS. 11 to 13 above, but the number density of the small injection holes 10' of the nozzle 9 is uneven, and the nozzle 9 is arranged above the center of the glass tube 1. It is moved at a constant speed to form a phosphor layer with uneven thickness. The rest is the same as the first embodiment of the present invention, and has the same effects.

As described above, in the method for forming a unevenly thick phosphor film in a fluorescent lamp of the present invention, the opening amount of the large number of small injection holes in the nozzle is increased in one direction, so that conventional equipment can be used as is. , and allows uneven thickness coating of the phosphor film without any change in manufacturability.
This has the effect of providing the desired fluorescent lamp at a low cost.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional general-use fluorescent lamp.
Figure 2 is its light distribution curve, Figure 3 is a cross-sectional view of a conventional reflector type fluorescent lamp, Figure 4 is its light distribution curve, Figure 5 is a cross-sectional view of the proposed fluorescent lamp, and Figure 5 is a cross-sectional view of the proposed fluorescent lamp. Figure 6 is a diagram of its light distribution curve, and Figure 7 is a comparison diagram of its light distribution curve when it is installed on the ceiling, where a is a general fluorescent lamp, b is a reflector type fluorescent lamp, and c is a proposed fluorescent lamp. A light distribution curve diagram, FIG. 8 is a cross-sectional schematic diagram of a device manufactured by a conventional manufacturing method, FIG. 9 is an enlarged view of its main parts, FIG. 10 is a horizontal cross-sectional diagram thereof, FIG. 12
13 is an enlarged sectional view of the nozzle, FIG. 14 is a sectional view of the nozzle of the first embodiment of the present invention, FIG. 15 is a longitudinal sectional front view of the nozzle, and FIG. FIG. 17 is a longitudinal sectional view of the second embodiment of the invention, FIG. 17 is a longitudinal sectional front view thereof, and FIG. 18 is an enlarged sectional view of the nozzle. 1...Glass tube, 4...Bottom side (front side), 5
...Top side (rear side), d ₁ , d ₂ ... Coating thickness, 6...
...phosphor layer, 8... fluorescent body fluid, 9... nozzle, 10'... small injection hole, 11... opening/closing valve.

Claims (1)

[Claims] 1 Place a nozzle on the central axis of the glass tube, form a predetermined number of small injection holes around the nozzle, and make the opening amount of the small injection holes large in one direction of the glass tube. A method for forming a unevenly thick phosphor film for a fluorescent lamp, characterized in that the phosphor is applied to the inner surface of the glass tube through a small injection hole.