JP3052394B2 - Method of forming a coating on the inner surface of a tubular valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating on the inner surface of a tubular bulb suitable for an aperture-type fluorescent lamp having an aperture for guiding light, and more particularly, to coating a coating such as a phosphor film on the inner surface of the bulb. The present invention relates to a method for forming a film on the inner surface of a tubular valve in which the coating process is improved.

[0003]

2. Description of the Related Art In general, an aperture type fluorescent lamp is widely used as a light source for a copying machine for diazo exposure or electronic exposure.

[0004] This is because an aperture-type fluorescent lamp concentrates light in a predetermined direction through a light-guiding aperture (aperture) to obtain an acute light distribution characteristic. As shown in FIG. 3, an example of this type of fluorescent lamp is provided with a band-shaped aperture 2 having a required width along the tube axis direction of a straight tubular glass bulb 1 over substantially the entire length.

[0005] As shown in the cross-sectional view of FIG.
An aperture 2 is provided on the inner peripheral surface of the valve 1 having a substantially circular cross section.
A reflective film 3 made of fine particles of a light-reflective substance such as alumina or titania is adhered to the inner peripheral surface over almost the entire length except for the entire surface,
A phosphor film 4 made of a phosphor material is applied to the entire inner peripheral surface of the reflection film 3 and a part of the inner surface of the bulb 1 inside the aperture 2. Therefore, on the inner peripheral surface of the bulb 1 where the band-shaped aperture 2 is located, the reflection film 3 is missing in a band shape,
The phosphor film 4 is directly applied.

[0006] As the aperture width of the aperture 2, that is, the opening angle θ is set smaller, the emitted light can be narrowed down in a specific direction, and a more acute light distribution characteristic can be obtained. Such a light distribution characteristic at an acute angle is desired for a light source of a copying machine.

When a film such as the reflective film 3, the phosphor film 4, or the protective film is applied to the inner peripheral surface of the bulb 1, the film is formed by a coating process shown in FIGS. After the solution is applied, it is dried and fired.

That is, first, a straight tubular glass bulb 1 having both ends opened is supported obliquely and rotatably, and a coating such as a reflection film 3 or a phosphor film 4 is formed from the inner peripheral surface of the upper end. While pouring the coating solution 5 for the first time, it is turned to the left (clockwise) as shown by an arrow in FIG.

For this reason, the coating solution 5 flows down on the inner peripheral surface of the valve 1 over almost the entire length from the upper end to the lower end, and flows out of the valve 1 from the lower end. On the other hand, at this time, the coating of the coating solution 5 is applied so as to extend almost to the left of the inner peripheral surface of the bulb 1.

When the rotation angle reaches a predetermined angle, the rotation is reversed rightward (counterclockwise) as shown by the arrow in FIG. After returning, the valve 1 is continuously inverted as shown in FIG. 3D, and after reversing the required angle, the valve 1 is again turned to the left as shown by the arrow in FIG. Stop the rotation. Then, a coating is formed by drying and solidifying and baking the coating solution 5 applied to the valve 1.

[0011]

However, in such a method for coating a coating, the diameter of the valve 1 is, for example, about 15 mm or more, and the coating angle of the coating solution 5 is about 30 mm.
There is no particular problem if it is about 0 ° or less, but if the diameter of the valve 1 is about 12 mm or less, or if the diameter is 15 mm
Even if the angle is less than about 320 °, when the coating angle is about 320 ° or more, the linearity of the left and right ends of the coating of the coating solution 5 applied to the valve 1 is deteriorated, and the coating angle, that is, the aperture 2 There is a problem that the accuracy of the opening angle θ is reduced.

That is, if the inner diameter of the valve 1 is 12 mm or less, the amount of the coating solution 5 to be poured is relatively large with respect to the inner diameter of the valve 1 as shown in FIG.
Although the area where a is formed is small, the area of the liquid pool 5b immersed in the coating solution 5 becomes large, and it is hardly expected that the surplus liquid of the coating solution 5 will fall by the weight of the coating 5a to form a thin film in the coating 5a. .

Therefore, when the amount of the coating solution 5 flowing into the valve 1 is reduced, the workability of applying the coating solution to the inner surface of the valve 1 is reduced due to the viscosity and surface tension of the coating solution 5.

On the other hand, if the thickness of the coating solution 5a of the coating solution 5 is small, the excess liquid of the coating solution 5 is reduced, the weight of the coating solution 5 is reduced, and it is difficult to flow. During coating, since the coating solution 5 has not been dried yet, due to the fluidity of the liquid, as shown in FIG. The accuracy of the angle θ decreases.

Accordingly, the present invention has been made in view of such circumstances, and an object thereof is to improve the linearity of the left and right ends of a coating film deposited on the inner peripheral surface of the valve and the accuracy of the deposition (application) angle. It is an object of the present invention to provide a method for forming a coating on the inner surface of a tubular valve. [Configuration of the invention]

[0016]

The present invention is configured as follows to solve the above-mentioned problems.

That is, the present invention relates to a method for forming a coating on the inner surface of a tubular valve having a coating step of applying a coating to a required central angle on the inner peripheral surface of the valve. Supporting, while pouring the coating solution for forming the coating from the upper end into the inner surface thereof, the valve is rotated around the central axis by a required angle in either the left or right direction, and then the rotation is reversed to reverse the rotation. When returning to the first pouring point of the coating solution, the reversal is stopped for a predetermined time, and then the valve is further rotated to the opposite direction to the above-mentioned rotation direction to apply the required center angle of the coating. And

[0018]

While the coating solution for forming the coating is poured from the upper end of the inner peripheral surface of the valve, the valve is rotated around the central axis by a required angle in either the left or right direction. Next, the direction of rotation of the valve is reversed, and when returning to the initial pouring point of the coating solution, the reversal is stopped for a predetermined time.

For this reason, while the reversal is stopped, the excess liquid at the tip of the coating solution applied to the inner peripheral surface of the valve falls downward by its own weight, and the thickness of the tip is made thin and uniform. And dripping is prevented.

As a result, the linearity of the tip is improved, and therefore, the accuracy of the coating solution application angle can be improved.

[0021]

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

FIG. 2 is a perspective view of a coating process of a coating in one embodiment of the present invention. In this embodiment, the inner diameter of the valve 11 is, for example, about 12 mm or less, and the coating angle of the coating is about 320 °. The following shows an example of a suitable coating method when the number exceeds the limit.

The bulb 11 is formed, for example, on an aperture-type fluorescent lamp shown in FIGS. 3 and 4 by coating a coating film such as a phosphor film, a reflection film, and a protective film on almost the entire inner peripheral surface thereof. Next, the coating process of the valve 11 will be described.

First, the valve 11 is supported obliquely so that its central axis is inclined at a required angle, and rotatably supported around the central axis.

A top end of a nozzle 13a of a supply device 13 into which a coating solution 12 for forming a film such as a phosphor film is poured faces an upper end portion of the valve 11 in the drawing. Are fixed to a fixed wall or the like (not shown).

Next, the coating solution 12 is continuously poured from the nozzle 13 a onto the inner peripheral surface of the upper end of the valve 11, and the coating solution 12 is allowed to flow from the upper end to the lower end of the inner peripheral surface of the valve 11. The coating solution 12 is applied over the entire length.

As described above, while the coating solution 12 is continuously poured onto the inner peripheral surface of the valve 11 at the pouring point OO (see FIG. 1A), first, the first pouring point O
The camera is rotated leftward (clockwise) as shown by a small arrow in FIG. 1B, for example, in one of the left and right directions of a, and when the rotation reaches a predetermined angle, the rotation direction is reversed.

By the reversal, as shown in FIG.
When the rotation angle of the valve 11 returns to the circumferential middle point of the coating film, that is, the first pouring point Oa, the reversal is stopped, for example, for about 1 to 3 seconds.

During this stop, as shown by the small arrow in FIG. 1 (C), a part of the surplus liquid of the coating solution 12 which has moved to the right side in the drawing flows to the pouring point OO along the inner peripheral surface of the coating due to its own weight. And the thickness of the film at the right end of the film becomes thinner.

For this purpose, the tip of the coating (FIG. 1C)
In this case, the dripping of the coating solution 12 at the right end is prevented to improve the linearity.

After the reversal is stopped, the reversal is further performed rightward as shown in FIG. 1 (D), and the rotation is temporarily stopped at a required angle, and at the same time, the pouring of the coating solution 12 is stopped.

Accordingly, in FIG. 1D, the vertical center line O
The tip of the coating solution 12 that has moved to the upper part of the valve 11 on the left side of v has a properly reduced thickness, so that dripping can be prevented.

After the rightward rotation is stopped, as shown in FIG. 1 (E), it is rotated leftward again, and the first pouring start point Oa is returned to the pouring point OO again, and the rotation is stopped. . Thereafter, the coating solution 12 is dried and fired, and the coating is applied on the inner peripheral surface of the valve 11 at a required angle.

Therefore, according to the present embodiment, the valve 11
Before reversing from left rotation to right rotation, the rotation is stopped at the circumferential middle part of the coating, so that the excess of the left and right ends of the coating solution 12 is lowered downward, and the left and right ends of the coating solution 12 are lowered. Since the thickness of the film solution is reduced, dripping of the coating solution 12 at the left and right end portions can be prevented.

For this reason, the linearity of the left and right ends of the coating solution 12 can be improved, and the accuracy of the deposition angle can be improved. In the above embodiment, the case where the phosphor film or the reflection film of the aperture type fluorescent lamp is formed has been described, but the present invention is not limited to this. For example, as in the case of a reflection type ultraviolet lamp having an aperture, The present invention is also applicable to a case where a reflective film is applied to the inner peripheral surface of the bulb 11 at a required angle. This ultraviolet lamp irradiates ultraviolet rays to a display panel or the like to which the phosphor is applied to cause the phosphor to emit light.

[0036]

As described above, according to the present invention, the valve is rotatably supported at an angle, and the valve is rotated alternately in the left-right direction while pouring the coating solution into the valve. Then, the rotation is stopped for a predetermined time, so that during this stop, the excess of the liquid component at the left and right ends of the coating solution is lowered downward, so that the film thickness can be made thin and uniform.

For this reason, dripping at the left and right ends of the coating solution can be prevented, and the linearity of the left and right ends can be improved. As a result, the accuracy of the coating angle of the coating can be improved.

[Brief description of the drawings]

1 (A) to 1 (E) are cross-sectional views of a valve showing respective steps of a film coating process in an embodiment of a method of forming a film on the inner surface of a tubular valve according to the present invention.

FIG. 2 is a perspective view of a coating process of the embodiment shown in FIG.

FIG. 3 is a perspective view of a general aperture type fluorescent lamp.

FIG. 4 is a cross-sectional view of the fluorescent lamp shown in FIG.

5 (A) to 5 (E) are cross-sectional views of a valve showing respective steps of a conventional coating process.

FIG. 6 is a cross-sectional view of the valve showing a coating state of the coating solution when the inner diameter of the valve is equal to or smaller than a predetermined value.

FIG. 7 is a partial perspective view showing a state of dripping by the conventional coating method shown in FIG.

[Description of Signs] 11 Valve 12 Coating solution

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 9/22 H01J 9/20

Claims (1)

(57) [Claims] 1. A method for forming a coating on the inner surface of a tubular valve having a coating process for applying a coating to a required central angle on the inner peripheral surface of the valve, wherein the coating process comprises: supporting the valve obliquely and rotatably; While pouring the coating solution for forming the coating from the upper end into the inner surface, the valve is rotated at a required angle around the central axis in any of the left and right directions, and then the rotation is reversed, and the coating solution is discharged. When returning to the first pouring point, the reversal is stopped for a predetermined time, and then the valve is further rotated to the opposite direction to the above-mentioned rotating direction to apply the coating at a required central angle. Method of forming a coating on the inner surface of a valve.