JPS5851890B2 - Manufacturing method for bent glass tubes for fluorescent lamps - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a glass tube for a fluorescent lamp (with a fluorescent material coated on the inner wall surface of the tube) bent into a relatively large bending angle such as a U-shape or an L-shape. .

As is well known, a fluorescent lamp is made up of a glass tube whose inner wall is coated with a fluorescent substance, and a cap with electrodes and pins is sealed at both ends. In addition to circular and circular shapes (so-called circle lines), there are demands for U-shaped, L-shaped, and other shapes bent at a considerably large bending angle depending on the application.

The present invention is an invention of an extremely excellent method for manufacturing curved glass tubes for fluorescent lamps, which have particularly large bending angles.

Conventionally, curved glass tubes for fluorescent lamps are manufactured using the following methods: 1) Fluorescent material is applied to the entire inner wall of the straight tube material in advance (usually, a fluorescent material in the form of liquid paint is poured into the tube, allowed to pass through, and then dried). A glass tube is provided in the application area, and the part of the glass tube to be bent is heated with a burner or the like to be bent into a U shape or the like.

2) A tube material not coated with a fluorescent substance is bent into a U-shape or the like, and a fluorescent substance is applied to the entire inner wall surface of the bent glass tube.

Manufactured by any of the following methods:

However, the conventional manufacturing method described above has the following drawbacks.

First, in the case of 1), due to the high heat applied to the part during bending, the fluorescent material combines or mixes with the semi-molten glass tube material, causing the material to turn gray and change its properties. It becomes brittle, difficult to bend, easily cracks, the finished surface becomes uneven, and the bent portion becomes flattened.

As a result, many products are defective due to cracks, etc., and the finished product has a poor appearance, and the internal diameter of the curved part is not constant, resulting in variations in electrical characteristics (starting voltage, discharge pressure, etc.) from product to product. Unevenness occurs in brightness.

In the case of 2), the bending processability is good, but the fluorescent material must be applied to the inner wall surface of the tube after bending.In this case, if the coating is done using the conventional method, unlike in the case of straight tubes, the coating film will inevitably deteriorate. The thickness is not uniform on the left and right sides (the areas where the paint is applied quickly dry quickly, resulting in a thicker coating in those areas), resulting in uneven coating, and the brightness on the left and right sides is not uniform, and the brightness may vary in some areas. Unevenness occurs.

The thicker the coating, the more expensive fluorescent paint is wasted.

The present invention eliminates all of the above-mentioned conventional drawbacks, and
In the glass tube material for fluorescent lamps, the curved part with the set dimensions to be curved is identified in advance, the inner wall surface of the tube in that part is left uncoated, and the entire inner wall surface of the tube other than the iron part is coated. First, a fluorescent substance is appropriately applied to the coated part, and then the uncoated part (curved part) of the glass tube in the coated part is heated and bent into the desired shape. It is designed to manufacture glass tubes.

Embodiments of the present invention will be described below with reference to drawings, taking the manufacturing of a U-shaped tube as an example. Reference numeral 1 is a straight glass tube, and the part to be bent into iron pipe 10 is defined as the bent part A, which has a set dimension L. (pipe dimensions required for bending), the inner wall surface of the pipe in part A is designated as non-coated part B, the entire other inner wall surface part of the pipe excluding iron part B is designated as coated part C, and the target light emission is applied to iron part C. Apply fluorescent substance 2.

In this coating process, for example, the glass tube 1 is placed upright in the coating rack 3, and the fluorescent material 2 is pushed up into the tube from below to the boundary line between B and C, and then discharged and coated.
b) Next, turn the above 1 over and apply it in the same way (opening in Figure 2) with the opposite end standing upright.

Thereby, the thickness of the coating film on the coating portion C of the left and right tubes can be made uniform.

Next, the non-coated part B of the glass tube 1 after the above coating process is completed.
The glass tube is heated with a burner 4 or the like and bent into the desired shape and bending angle to produce the desired bent glass tube.

(FIG. 3) Thereafter, the caps 5 are sealed to both tube ends of the completed curved glass tube as in the conventional method to complete the fluorescent lamp (FIG. 4).

As described above, the present invention provides a glass tube 1 with a non-coated area B and a coated area C that are clearly distinguished from each other, applies a fluorescent substance only to the coated area C, and leaves the non-coated area B to remain in the glass tube. ＼Since the iron part B is heated and bent,
It has excellent manufacturing process and product features such as lack of defects.

1) Since the non-applied area where the fluorescent substance is not applied is heat-processed, it can be bent very easily and accurately in the same way as simply bending a glass tube, and naturally it can be freely processed into various shapes.

2) Since the bending process is easy and there is no mixing of fluorescent substances as in the conventional case, no cracks occur after the process.

3) The finished appearance is beautiful.

4) Good workability keeps the inner diameter of the pipe constant at the curved part.
Therefore, there is no variation in electrical characteristics from product to product.

5) Since it can be processed at a relatively low temperature (if a fluorescent material is coated, it is difficult to process it unless it is at a high temperature), the processing speed is fast and work efficiency can be improved.

6) Since the fluorescent coating can be applied separately to the left and right tubes with the curved part as the boundary, the thickness of the left and right coatings can be adjusted uniformly, resulting in good luminous efficiency and uniform brightness on the left and right sides. .

7) Furthermore, there is no uneven coating, and expensive fluorescent materials can be saved.

8) Area where the glass tube is not coated with fluorescent material (uncoated area)
Of course there exists\, but as a result of various measurements, it was no inferior to the conventional product where the entire pipe was coated.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view of a glass tube before bending processing, Fig. 2 is an explanatory view of the fluorescent substance coating process, Fig. 3 is an explanatory cross-sectional view of a glass tube bent by the method of the present invention, and Fig. 4 is an explanatory cross-sectional view of a glass tube before bending. FIG. 1 is a diagram of a fluorescent lamp using the product of the present invention. Number, A... Curving part with set length, B...
...Non-coated area, C...Coated area, D...
Completed curved glass tube, 1...Glass tube, 2...
...Fluorescent material, 3...Painting, 4...
... Burner 5 ... Base.

Claims (1)

[Claims] 1. In a glass tube material for a fluorescent lamp, a curved portion having a set dimension is specified, and the inner wall surface of the tube in this portion is set as a non-coated portion,
A fluorescent substance is applied to the entire inner wall surface of the tube except for the iron part, and a glass tube consisting of a coated part and a non-coated part is provided as the coated part.
A bent glass tube is manufactured by heating and bending the uncoated portion of an iron tube into a desired shape. A method for manufacturing bent glass tubes for fluorescent lamps.