JPH0785398B2 - Exposure device for forming fluorescent surface - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a fluorescent surface forming exposure apparatus suitable for use in forming a fluorescent surface of a color picture tube having an in-line type electron gun.

[Technical Background of the Invention] Generally, red (R), green (G), and blue (B) three-color phosphor dots or three-color phosphors are provided on the inner surface of a panel of a color receiver having an in-line type electron gun. When forming a fluorescent surface consisting of stripes, first, a black light absorbing layer is formed with high precision so as to cover the circumference of the region where the three-color fluorescent substance dots or the three-color fluorescent substance stripes are to be formed. . Next, a method of forming a fluorescent material layer so as to be embedded in a hole portion of the black light absorbing layer is general, and the black light absorbing layer and the fluorescent material layer are formed by a photographic method including exposure. It

That is, the conventional exposure apparatus for forming a fluorescent surface is configured as shown in FIG. 4, and the panel 2 and the shadow mask 3 on which the fluorescent surface is to be formed are installed so as to cover the opening of the container 1. . Opposed to the shadow mask 3, the light distribution correction filter 4, the γ-Δp correction lens 5, and the γ-
The Δs correction lens 6 and the light source 7 are arranged at a predetermined interval. The exposure of the black light absorption layer formed on the inner surface of the panel 2 is performed by one exposure apparatus by moving the position of the light source 7 corresponding to the exposure of each of the three colors. .

By the way, in the above case, the light source 7 moves corresponding to each color exposure. The γ-Δp correction lens 5 is an aspherical lens (main lens) that mainly corrects the γ-Δp characteristic, and usually one lens is commonly used for three colors. Also, γ-Δ
The s-correction lens 6 is a lens that mainly corrects the γ-Δs characteristic, and is shown as a single lens in the drawing, but it may be configured by several lenses corresponding to each color. Where γ
The -Δp characteristic is a movement characteristic of the electron beam deflection center in the tube axis direction with respect to the deflection angle, and the γ-Δs characteristic is a characteristic of a change in the distance between the side beam deflection centers with respect to the deflection angle. Further, the light distribution correction filter 4 plays a role of continuously controlling the hole diameter of the black light absorbing layer and the fluorescent substance dot diameter in the central portion and the peripheral portion of the panel 2.

[Problems of Background Art] In general, the convergence characteristics of an in-line convergence-free deflection yoke are as shown in FIG.
Since green has a narrow pattern with respect to red and blue, for example F /
By attaching a magnetic material called C (Field Controller) to the tip of the electron gun, the deflection magnetic field on the electron gun side with respect to the green beam (center beam) is made stronger than the red and blue side beams, and this is corrected. Yes (green sensitivity correction). In the figure, 8 indicates a red / blue raster, and 9 indicates a green raster.

However, in the above method, although the convergence pattern is corrected, as shown in FIG. 6, the movement trajectory of each beam is such that the green beam starts to be deflected relatively earlier than the red beam and the blue beam. Then, the deflection center comes to be closer to the electron gun than red and blue (Fig. 6 is exaggerated, 10 is a green beam trajectory, 11 is a red / blue beam trajectory, and 13 is a green beam deflection. Center, 14 is the red / blue beam deflection center). As a result, when the conventional exposure apparatus for forming a fluorescent surface as described above is used, the landing characteristics tend to shift the green beam inward with respect to the red and blue beams, as shown in FIG. Incidentally, 15-R, 15-G, 15- in FIG.
B is the reaching beam bundle of red, green, and blue, and is 16-R, 16-
G, 16-B are red, green and blue phosphor dots.

Further, in the diagonal portion, an error that is a composite of errors on the horizontal axis and the vertical axis occurs. FIG. 7 shows the case of the dot type, and the dot type will be described below. When the mislanding as shown in FIG. 7 occurs, the electron beam does not cause the entire phosphor dots to emit light, and there is a drawback that the brightness and color purity are easily deteriorated.

[Object of the Invention] An object of the present invention is to form a phosphor dot so as to match each beam and correct a landing error between a green beam, a red beam, and a blue beam, thereby preventing deterioration of brightness and color purity. It is an object of the present invention to provide an exposure apparatus for forming a fluorescent surface which is prevented.

SUMMARY OF THE INVENTION The present invention is an exposure apparatus for forming a fluorescent surface, in which a γ-Δs correction lens is composed of at least two types of lenses for green, red, and blue, and the center thickness of each lens is different. is there.

[Embodiment of the Invention] Like the conventional example (see FIG. 4), the exposure apparatus for forming a fluorescent surface of the present invention covers a fluorescent surface (fluorescent material dots or fluorescent dots) so as to cover the opening of the container 1. A panel 2 on which an optical stripe) is to be formed and a shadow mask 3 having a large number of small holes are installed. A light distribution correction filter 4, a γ-Δp correction lens 5, a γ-Δs correction lens 6, and a light source 7 are arranged at predetermined intervals in the container 1 so as to face the shadow mask 3.

In this case, the γ-Δs correction lens 6 is different from the conventional one and is composed of at least two types of lenses, a flat lens and a wedge lens, which are exchanged in response to each color exposure, and the flat lens and the wedge lens are It is formed so that the respective center thicknesses are different from each other.

That is, the γ-Δs correction lens used in the present invention is configured as shown in FIGS. 1 (a), (b) and (c), and has a wedge lens for blue 27-B and a flat lens for green. 27-G, red wedge lens 27-R. Moreover, as shown in the drawing, the center thickness t of the green plate lens 27-G is
Center thickness T of each wedge lens 27-B, 27-R for blue and red
It is set thinner (T> t).

The wedge lenses 27-B and 27-R for blue and red may basically have the same shape, but the directions of use are different by 180 °.
Then, by reducing the lens thickness t of the flat plate lens 27-G for green, as shown in FIGS. 2 (a) and 2 (b),
The green phosphor dots 16-G are the red and blue phosphor dots 16-
It is formed inside R and 16-B.

In this way, the thicknesses of the wedge lens for blue 27-B, the flat plate lens for green 27-G, and the wedge lens for red 27-R, which are γ-Δs correction lenses, should be optimally designed. By doing so, it is possible to correct the amount of deviation of the beam with respect to the phosphor dots as described above, and achieve the best landing for blue, green, and red. As a design example, in a 14V, 0.31 mm pitch tube, the flat lens 27-G for green is 3.3 mm, and the wedge lenses 27-B and 27-R for blue and red are 4.0 mm.

The exposure apparatus for forming a fluorescent surface of the present invention is the above-mentioned γ-Δs.
Except for the correction lens, it has the same configuration as the conventional example (FIG. 4),
Detailed description is omitted.

Further, FIG. 3 shows an example of a method of exchanging the γ-Δs correction lens. In the figure, 7 is a light source, 46 is a lens frame, 47 is a rotation direction of the lens frame 46, 48 is a rotation axis, 42-B, 42. -R, 42-G is γ-
The Δs correction lenses 45-B and 45-R show the inclination tendency of the wedge lenses for blue and red.

Further, in the above embodiment, the case where the fluorescent body is the dot type has been described, but it goes without saying that the present invention can be applied to the case where the fluorescent body is the stripe type.

[Effects of the Invention] According to the present invention, it is possible to make the imbalance tendency of the phosphor dot trio substantially match the imbalance tendency of the beam trio. As a result, it is possible to prevent the deterioration of the brightness and the color purity due to the difference in the imbalance tendency between the beam trio and the phosphor dot trio.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A, FIG. 1B, and FIG. 1C are sectional views showing a γ-Δs correction lens used in a fluorescent surface forming exposure apparatus of the present invention,
FIG. 2 is an explanatory diagram showing an array of three-color phosphor dots and beam landing when the exposure apparatus for forming a fluorescent surface of the present invention is used, and FIG. 3 is a plan view showing a method of exchanging a γ-Δs correction lens. 4 and 5 are sectional views showing a conventional exposure apparatus for forming a fluorescent surface, FIG. 5 is a plan view showing a convergence error in a self-convergence type deflection yoke, and FIG. 6 is an F / C. And FIG. 7 is a plan view showing the landing error in the case of FIG. 1 ... Container, 2 ... Panel, 3 ... Shadow mask, 4
...... Light distribution correction filter, 5 γ-Δp correction lens, 6
...... γ-Δs correction lens, 7 ... Light source, 27-B ... Blue wedge lens, 27-G ... Green flat lens, 27-R
...... Red wedge lens.

Claims (2)

[Claims] 1. A shadow mask having a large number of small holes which are arranged so as to face each other inside a panel where a fluorescent surface is to be formed, a light source which is arranged so as to face the shadow mask, the light source and the shadow. An exposure apparatus for forming a fluorescent surface, comprising: a correction lens disposed between masks and performing exposure corresponding to three-color fluorescent dots or three-color fluorescent stripes by one unit. Comprises two stages of a lens or lens group commonly used for the exposure of each color and at least two lens groups of a flat lens and a wedge lens exchanged for each color exposure, and An exposure apparatus for forming a fluorescent surface, wherein the center thicknesses of the flat lens and the wedge lens are different from each other. 2. The exposure apparatus for forming a fluorescent surface according to claim 1, wherein the center thickness of the flat lens is thinner than the center thickness of the wedge lens.