JPH0418655B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for exposing a phosphor surface of a color cathode ray tube, and particularly to a method of exposing the phosphor surface of a color cathode ray tube. The present invention relates to a method of exposing a fluorescent surface of a color cathode ray tube that can be corrected.

[Technical background of the invention and its problems]

In an in-line color cathode ray tube, the spacing between the red band-shaped phosphor layer and the blue band-shaped phosphor layer corresponding to the electron beams (usually for red and blue) on both sides of the three-color phosphor layers on the phosphor surface is fluorescein. Approximately 2/2 of the horizontal pitch of the electron beam passage hole of the shadow mask over the entire optical surface.
It is designed to be 3. The distance between the red band-shaped phosphor layer and the blue band-shaped phosphor layer is called the electron beam landing degrouping characteristic (hereinafter referred to as σ characteristic). This also applies to the case of a dot-in-line phosphor layer in which a red dot-shaped phosphor layer and a blue dot-shaped phosphor layer are formed in-line.

Furthermore, in the design of the deflection yoke in an in-line color cathode ray tube, the horizontal and vertical deflection magnetic fields are non-uniform magnetic fields in order to achieve dynamic convergence around the periphery of the fluorescent surface. Therefore, the σ characteristic at the center of the fluorescent surface tends to be a group. In order to correct this and make the σ characteristic constant over the entire phosphor surface, a simple wedge lens is used as a σ characteristic correction lens when exposing the red phosphor layer, as shown in Figure 1. 1, and move the shutter 3 vertically up and down the fluorescent surface (in the direction of the arrow) using the convex cam 2a on the panel position controller (hereinafter referred to as PPC), and move it to the periphery of the fluorescent surface. Therefore, the correction amount of the σ characteristic is sequentially increased. When exposing the next green phosphor layer, the simple wedge lens 1 is rotated 90 degrees as shown in Fig. 2, and the shutter 3 is moved vertically up and down (in the direction of the arrow) of the phosphor surface using the flat cam 2b on the PPC. move it. That is, the σ characteristics are irrelevant when exposing the green fluorescent layer, and no correction is made around the fluorescent surface. When exposing the next blue phosphor layer, the simple wedge lens 1 is further rotated 90 degrees as shown in FIG. , and as you move closer to the fluorescent surface, σ
This is done by gradually increasing the amount of characteristic correction.

In the black stripe coating process, the red, green, and blue color phosphor layers are normally exposed continuously using one exposure device.

As a result, the correction of the σ characteristics on the horizontal axis can be made almost uniform by selecting the inclination angle of the simple wedge lens 1, and the correction of the σ characteristics on the vertical and diagonal axes can be made by selecting the curvature coefficients of the cams 2a and 2c. By doing so, it is possible to make it almost uniform in terms of design.

However, recent deflection yokes include dynamic convergence, pincushion correction free types, and 110° deflection tubes, and the amount of correction for the σ characteristics of the vertical, horizontal, and diagonal axes has become different. It is becoming difficult to correct the σ characteristics over the entire phosphor surface by correcting only the tilt angle and cam coefficient of a simple wedge lens.

That is, when the phosphor surface ₂₃₁ of a color cathode ray tube using a recent deflection yoke is formed by the method shown in FIGS. The relationship is as follows, and at the edge of the horizontal axis (H), |(R-
The offset amount (d) expressed by G) - (G - B) | = d is almost zero, but at the edge of the diagonal axis (D), d > zero, and the amount of correction of the σ characteristic is insufficient. I come to do it.

As a countermeasure for this, it is possible to perform the correction as shown in FIG. 6 by moving both the light source 4 and the main correction lens 5 upward on the vertical axis as shown in FIG. By moving the light source 4 and the main correction lens 5 upward on the vertical axis, light that reaches above the diagonal axis of the phosphor surface due to the relationship of the incident angle of the light rays passes through the green band-shaped phosphor layer (G) vertically. This is because the light rays that move closer to each other in the axial direction and reach diagonally downward move the edge band-like phosphor layer (G) away from the vertical axis. However, it is extremely difficult to move the light source 4 and the main correction lens 5 in this manner due to the mechanism of the exposure apparatus.

In addition, as a countermeasure when the PPC cam mechanism is not used, there is an idea to use a σ characteristic correction lens 11 with an aspherical lens curved surface as shown in FIG. As shown in Fig. 8, when forming the green band-shaped phosphor layer (G) at the edge, there is a marked change in the shape of the lens 11.
Since 1 _j and 11 _k are used, cross-graining occurs at the edges of the horizontal axis (H) and diagonal axis (D). For example 19V90°
For pipes, the amount of offset at the edge of the horizontal axis (H) is approximately 40 μm.
becomes. For this reason, a problem arises in that this correction lens 11 cannot be used for exposure of the edge band-shaped phosphor layer (G); (G) or each band-shaped phosphor layer (R), (G), and (B) must be separated. In this case, two or three exposure stands will be required for the black stripe process, instead of the current method of printing three colors on the same exposure stand, which will cause problems in managing the stripe size and equipment problems. .

[Purpose of the invention]

The present invention was developed in view of the conventional problems described above, and eliminates the need for a panel position controller, uses an aspherical correction lens as the σ characteristic correction lens for the phosphor layer, and requires only one exposure stand. in,
It is an object of the present invention to provide a method for exposing a color cathode ray tube fluorescent surface, which can form a fluorescent surface consisting of band-shaped or dot-in-line fluorescent layers of three colors red, green, and blue without cross-grain.

[Summary of the invention]

That is, the present invention provides a belt-shaped or dot-line shaped 3
In an exposure method for a color cathode ray tube fluorescent surface having a fluorescent surface composed of color phosphor layers, an aspherical correction lens for correcting the σ characteristic is used, and In contrast to the arrangement of the aspherical correction lens when exposing one of the phosphor layers on both sides, when exposing the other phosphor layer, the aspherical correction lens is adjusted by 180°. When rotating and exposing the central phosphor layer of the three color phosphor layers, the aspherical correction lens is rotated 90° clockwise relative to the position when exposing the one phosphor layer. A method for exposing a phosphor surface of a color cathode ray tube, characterized in that the phosphor layer of a color cathode ray tube is rotated and the exposure light source is positioned farther from the aspherical correction lens than when exposing the phosphor layers on both sides. .

[Embodiments of the invention]

Next, an embodiment of the method of exposing a fluorescent surface of a color cathode ray tube according to the present invention will be described with reference to FIGS. 9 to 11. In the figure, the same reference numerals as in the conventional example indicate the same parts.

First, FIG. 9 is a diagram showing the state when exposing the red band-shaped phosphor layer (R) among the phosphor layers on both sides, in which a panel 23 with a shadow mask inside is placed on the mounting table 21 of the exposure device 20. The exposure light source 4 ₁ is placed at a distance (L) from the mounting table 21 . The light from this exposure light source ₄₁ passes through an aspherical correction lens 11 as a σ characteristic correction lens and a main correction lens 5 to form a red phosphor layer (R) on the inner surface of the panel. In the case of the blue phosphor layer (B), the aspheric correction lens 5 may be rotated by 180 degrees.

The following Figure 10 shows the case where a green band-shaped phosphor layer (G), which is the central phosphor layer, is formed by exposure.
and the exposure light source 4 ₂ is (L+α), and the aspheric correction lens 11 is rotated 90° clockwise relative to the exposure formation of the red band-shaped phosphor layer (R).
(H) The amount of offset on the upper periphery is made almost zero. In the case of a 19V 90° color cathode ray tube, if the grain size of the conventional method is 40 μm, it is half that amount.
A correction of 20 μm is approximately 0.7 mm in terms of α.
In this case, as shown in FIG. 5, by moving the light source 4 ₂ and the main correction lens 5 in the V-axis direction or by changing the shape of the aspherical correction lens, the diagonal axis (D) line can be further adjusted. Cross-eyed look at the edges can also be eliminated.

Next, when the light source 4 ₁ is changed to 4 ₂ , the movement of the exposure light beam with respect to the green band-shaped phosphor layer will be explained using FIG. 11. For L during exposure of the red and blue band-shaped phosphor layers,
By moving the edge band-shaped phosphor layer to the position L+α during exposure and moving it away, the exposure light beam passing through the electron beam passage hole of the shadow mask ₂₂ moves from the solid line to the position indicated by the broken line. This results in 24 directions, and the amount of cross-grain is corrected.

It goes without saying that the aforementioned movement from the light source 4 ₁ to 4 ₂ may be performed manually within the exposure apparatus, or may be performed automatically.

〔Effect of the invention〕

According to the method of exposing the fluorescent surface of a color cathode ray tube of the present invention, the white uniformity of the color cathode ray tube is improved, and each strip or dot-in-line phosphor layer is coated with one exposure device in the black coating process. This makes it possible to expose the area to be coated, and it is possible to suppress manufacturing variations that occur when multiple exposure devices are used, which is of great industrial value.

[Brief explanation of drawings]

Figures 1 to 4 are diagrams showing an example of a conventional method of exposing the phosphor surface of a color cathode ray tube. An explanatory diagram showing the time of exposure of the strip-shaped phosphor layer, FIG. 3 is an explanatory diagram showing the time of exposure of the blue strip-shaped phosphor layer, and FIG. 4 shows the relationship between each strip-shaped phosphor layer on the phosphor surface. Explanatory diagram,
FIGS. 5 and 6 are diagrams showing other examples of the conventional method of exposing the fluorescent surface of a color cathode ray tube, and FIG. 5 is an explanatory diagram showing a state in which the light source and the main correction lens are moved on the V axis; FIG. 6 is an explanatory diagram showing the relationship between each band-shaped phosphor layer according to FIG. 5, and FIGS. 7 and 8 are diagrams showing still another example of the conventional method of exposing the phosphor surface of a color cathode ray tube. FIG. 7 is a perspective view showing an aspherical σ characteristic correction lens, FIG. 8 is an explanatory diagram showing the relationship between each band-shaped phosphor layer when the correction lens shown in FIG. 7 is used, and FIGS. 9 to 11 9 is a diagram showing an embodiment of the method for exposing a phosphor surface of a color cathode ray tube according to the present invention, and FIG. An explanatory diagram showing
FIG. 10 is an explanatory diagram showing an exposure device for exposing a green band-shaped phosphor layer and each band-shaped phosphor layer on a fluorescent surface;
FIG. 11 is an explanatory diagram showing the movement of the exposure light beam on the fluorescent surface when the distance between the mounting table and the light source is changed. 1, 11...σ characteristic correction lens, 2a, 2b,
2c...Cam, 3...Slit, 4, 4 ₁ , 4 ₂ ...
...Light source, 5...Main correction lens, 23 ₁ ...Fluorescent surface,
23...Panel.

Claims (1)

[Claims] 1. In an exposure method for a color cathode ray tube fluorescent surface having a fluorescent surface consisting of a band-shaped or dot-line three-color phosphor layer, an aspheric correction lens for correcting the σ characteristic is used, and one of the three-color phosphor layers is With respect to the phosphor layers on both sides, when exposing one of the phosphor layers on both sides, the arrangement of the aspherical correction lens corresponds to the arrangement when exposing the other phosphor layer. Rotate the aspherical correction lens by 180 degrees, and when exposing the central phosphor layer of the three color phosphor layers, place the aspherical correction lens in the same position as when exposing one of the phosphor layers. The color cathode ray tube is rotated 90° clockwise relative to the phosphor layer, and the exposure light source is positioned further away from the aspherical correction lens than when exposing the phosphor layers on both sides. How to expose the light surface.