JP3160946B2 - Phosphor film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fluorescent film having a uniform thickness on the entire inner surface of the face of a cathode ray tube.

[0002]

2. Description of the Related Art As shown in FIG. 2, a cathode ray tube has a shallow bowl-shaped face portion (1) on the front side and a funnel portion which is provided continuously from the rear end opening side of the face portion (1) and has a gradually decreasing diameter. (2)
And a neck portion (3) connected to the funnel portion (2) having the smallest diameter. However, the face part (1), the funnel part (2) and the neck part (3) are initially separate bodies and are integrated by glass welding.
Prior to integrating the face part (1) with the funnel part (2) and the neck part (3), a fluorescent film (4) is formed on the inner surface (1b) of the face part (1).

The fluorescent film (4) is formed through the steps shown in FIGS. First, as shown in FIG. 3, the holder (5) that rotates and rotates adsorbs the front surface (1a) of the face portion (1), and as shown by a virtual line, the opening side inner surface (1b) of the face portion (1). ) Is turned from the horizontal posture of 0 ° downward to the horizontal posture with the inner surface (1b) facing upward by turning until the elevation angle (θ) becomes 180 ° as shown by the solid line. Inner surface (1b) of this face part (1)
A nozzle (6) is arranged above the nozzle, and a phosphor suspension (7) containing a photosensitive agent is injected from the nozzle (6). At this time, the holder (5) moves the face (1) at 10 rpm to 20 r.
Spin at a speed of pm, and apply the phosphor suspension (7) so as to spread only to the center of the inner surface (1b) of the face (1). If the rotation speed of the face portion (1) is set to a high speed as described later, the phosphor suspension (7) scatters to the peripheral portion, does not remain at the center portion, and does not remain at the center portion. The fluorescent film (4) is not formed at the center of the inner surface (1b). Therefore, the rotation speed of the face part (1) is set to 10 rpm to 20 r.
As pm, the phosphor suspension (7) is applied to the center. After a predetermined amount of the phosphor suspension (7) is applied to the center of the inner surface (1b) of the face (1), the injection of the phosphor suspension (7) is stopped, and the nozzle (6) is turned off. Exclude.
Then, the holder (5) rotates the face (1) from 180 rpm.
Spin at a high speed of 260rpm. Then, the face part (1)
Phosphor suspension (7) applied to the center of the inner surface (1b)
Is scattered from the center of the inner surface (1b) of the face portion (1) to the peripheral portion by centrifugal force, and a part of the phosphor suspension (7) jumps out from the end face of the face portion (1). Thus, the phosphor suspension (7) is applied to the entire inner surface (1b) of the face portion (1). Then, the face part (1)
Is transported to the drying step with its rotation speed changed. Then, when the phosphor suspension (7) is dried, a phosphor film (4) is formed on the entire inner surface (1b) of the face portion (1).

[0004]

SUMMARY OF THE INVENTION Phosphor suspension (7)
Is applied to the center of the inner surface (1b) of the face portion (1), and then the face portion (1) rotates at a high speed of 180 rpm to 260 rpm, and a centrifugal force is applied to the face portion (1).
Is scattered around the inner surface (1b). Since the centrifugal force is larger at the peripheral part than at the central part, the phosphor suspension (7) spreads thinly at the peripheral part and tends to be applied thicker at the central part. Then, the phosphor film (4) formed by drying the phosphor suspension (7) is thicker at the center of the inner surface (1b) of the face (1) and thinner at the periphery, and the brightness at the center is lower. There was a problem that the brightness became brighter than the luminance of the peripheral portion and the central portion appeared whitish.

For this reason, the elevation angle (θ) of the face portion (1)
There are some ideas, such as setting the robot to a 90 ° vertical position and rotating it at high speed, but it was not enough.

Accordingly, an object of the present invention is to provide a method for forming a fluorescent film (4) capable of applying a uniform fluorescent film (4) on the inner surface (1b) of the face portion (1).

[0007]

According to the present invention, in order to achieve the above object, the opening inner surface of the shallow bowl-shaped face portion is turned upward by setting the downward horizontal posture to 0 °.
In a horizontal attitude of °, the phosphor suspension is dropped on the inner surface of the face part, and the face part rotates at a speed of about 20 rpm,
After applying the phosphor suspension to the center of the inner surface of the face,
The face is shifted from 180 ° horizontal position to 100 ° -140.
Angle of inclination, face rotation speed more than 3 seconds
Over gradually accelerated to the speed of 180Rpm～260rpm, it is intended to applied to the periphery of the inner surface of the face portion by the centrifugal force of the phosphor suspension.

[0008] Features of the present invention, as described above face part
The time required for gradually increasing the rotation speed of the motor to 180 to 260 rpm is 3 seconds or more .

[0009]

The phosphor suspension applied to the center of the inner surface of the face portion gradually drops from the center of the inner surface toward the peripheral portion when the face portion is inclined at an inclination of 100 ° to 140 °. As the face rotates at 180 to 260 rpm, it is uniformly scattered around the inner surface of the face by centrifugal force, and the entire inner surface is coated with the phosphor suspension.

If the time for changing the rotation speed of the face portion to high speed is set to 3 seconds or more, it scatters while dripping appropriately,
The phosphor suspension is applied more uniformly.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIG. However, the same parts as those in the related art are denoted by the same reference numerals,
The description is omitted.

First, in the same manner as in the prior art, the opening side inner surface (1b) of the face portion (1) changes its orientation from the horizontal position with the downward horizontal position of 0 ° to the horizontal position with the elevation angle (θ) of 180 °. The inner surface (1b) of (1) faces upward. In this state, while rotating the face part (1) at about 20 rpm,
The phosphor suspension (7) is dropped onto the inner surface (1b) of the face portion (1) from a nozzle (6) disposed above the face portion (1), and the phosphor suspension (7) is applied to the face portion. It is applied only to the center of the inner surface (1b) of (1) (see FIG. 3). A predetermined amount of the phosphor suspension (7) is applied to the inner surface (1b) of the face (1).
After being applied to the center, the dripping of the phosphor suspension (7) from the nozzle (6) is stopped, and the nozzle (6) is removed from above the face portion (1).

Next, as shown in FIG. 1, the face portion (1) is inclined from 100 ° to 140 ° in elevation angle (θ) from a posture in which the inner surface (1b) side of the face (1b) faces downward and the horizontal posture is 0 °. Turn around. In this inclined position, the face (1) is
Rotate at a speed of 0-260 rpm. Rotation speed about 20 rpm
From 3 to over 180 seconds to change from 180rpm to 260rpm,
The moving speed of the phosphor suspension (7) is reduced. if,
Elevation (θ) is 100 ° or less
When the face (1) is rotated at 180 rpm to 260 rpm, the phosphor suspension (7) is immediately dropped from the center of the inner surface (1b) to the periphery, and the face (1) is rotated. However, the phosphor suspension (7) is not scattered from the central portion of the face portion (1) to the entire peripheral portion, and the fluorescent film (4) cannot be formed on the entire inner surface (1b) of the face portion (1). . Also, if the elevation angle (θ) is set to a horizontal posture of 140 ° or more,
As described above, the phosphor suspension (7) remains in the central portion of the face portion (1) in an amount more than a required amount, and the fluorescent film (4) whose central portion is thicker than the peripheral portion is formed. Therefore, the elevation angle (θ) of the face portion (1) is set to 100 ° to 140 ° to optimize the moving speed of dropping, and the face portion (1) is rotated at 180 rpm to 260 rpm. If the rotation speed is 180 rpm or less, the centrifugal force is insufficient and the phosphor suspension (7) is not scattered to the periphery of the inner surface (1b) of the face portion (1), and the inner surface of the face portion (1). The fluorescent film (4) is no longer formed around (1b),
Further, the thickness of the fluorescent film (4) at the center of the inner surface (1b) of the face portion (1) may be increased. Conversely, if the rotation speed is 260 rpm or more, the difference in the centrifugal force between the central portion and the peripheral portion of the face portion (1) becomes too large, and a uniform fluorescent film (4) cannot be formed. Therefore, the elevation angle (θ) of the face portion (1)
100 ° to 140 °, and the rotation speed is 180rpm to 260r
pm, the phosphor suspension (7) applied to the center of the face (1) is dispersed while optimizing the balance between the liquid dripping in the radial direction and the liquid scattering in the peripheral direction due to centrifugal force. Splash. Furthermore, the rotation speed of the face part (1) is about 20 rpm
By setting the time for changing the speed from 180 rpm to 260 rpm to 3 seconds or more, the phosphor suspension (7) is not scattered at a stretch to the periphery of the inner surface (1b) of the face portion (1), and the phosphor suspension According to the viscosity, (7) moves gently to the peripheral portion of the inner surface (1b) and scatters to be applied evenly to the entire inner surface (1b). Thereafter, the face part (1) is conveyed to a drying step, and the phosphor suspension (7) is dried, so that the entire inner surface (1b) of the face part (1) has a uniform thickness of the fluorescent film (4). Is formed.

[0014]

According to the present invention, since a uniform fluorescent film is formed on the inner surface of the face portion, it is possible to manufacture a high-quality cathode ray tube without luminance unevenness.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view when a fluorescent film is formed according to the present invention.

FIG. 2 is a front view of a cathode ray tube.

FIG. 3 is a schematic sectional view when a fluorescent film is formed by a conventional method.

FIG. 4 is a schematic sectional view when a fluorescent film is formed by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Face part 1b Inner surface 4 Phosphor film 7 Phosphor suspension θ Elevation angle indicating attitude of face part

Claims (1)

(57) [Claims] 1. An inner surface on the opening side of a shallow bowl-shaped face portion is turned upward with a downward horizontal attitude of 0 °.
In a horizontal posture of 0 °, the phosphor suspension is dropped on the inner surface of the face portion, the face portion is rotated at a speed of about 20 rpm, and the phosphor suspension is applied to the center of the inner surface of the face portion. Face part is 100 ° -1 from 180 ° horizontal posture
Tilt to a 40 ° tilt position and rotate face face for 3 seconds
Phosphor layer forming method comprising applying to the periphery of the inner surface of the face portion by gradually accelerated to the speed of 180Rpm～260rpm, centrifugal force phosphor suspension over a period.