JPH088061B2 - Exposure device for forming fluorescent screen of color picture tube - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an exposure apparatus for forming a fluorescent screen of a color picture tube, and more particularly to a spherical surface having slot-shaped through holes linearly arranged through a bridge. Using the shadow mask of
The present invention relates to an exposure device for forming a fluorescent screen of a color picture tube, which is used when a stripe-shaped phosphor layer or a light absorption layer (black material layer) is formed on the inner surface of a spherical panel.

[Technical background of the invention and its problems]

The phosphor layer forming the phosphor screen of the color picture tube is coated with a phosphor slurry using a sensitized photosensitive resin on the inner surface of the panel, and the coating film is exposed through a shadow mask to expose the desired portion of the photosensitive resin. It is formed by exposing it to light and then developing it. The same applies when a black material layer is formed between the phosphor layers to improve the contrast.

In the above-described exposure, a spherical shadow mask in which slot-shaped through holes are linearly arranged through a bridge is used, and a spherical panel corresponding to the array of the slot-shaped through holes of the shadow mask is used. When forming a fluorescent surface consisting of a stripe-shaped phosphor layer or a black material layer on the inner surface,
Usually, a long linear light source that is long and narrow in the direction in which the slot-shaped through holes are arranged is used as the light source. However, when such a long light source is used, the projection of the long light source onto the inner surface of the panel is rotated due to the three-dimensional geometrical relationship based on the shapes of the light source, the shadow mask, the panel, etc., and as shown in FIG. In particular, meandering stripes (2) are formed at the corners of the panel (1), and as a result, the landing characteristics of the electron beam are impaired, resulting in a color picture tube with poor color purity.

Conventionally, various techniques for correcting the meandering of the stripe (2) have been developed. As an example thereof, there is an exposure apparatus in which a negative meniscus lens (4) is arranged so as to cover the light source (3) as shown in FIG. When the exposure apparatus is constructed in this way, as shown in FIGS. 6 (A) and 6 (B), the negative meniscus lens (4) has radii R ₁ , R ₂ (R ₁ <R _{1 2} ) Approximate sphere, and 3
Since it has a dome shape of 60 ° rotational symmetry, the light reaching the panel (5) from the light source (3) corresponds to each point of the long light source from the actual light source position as shown by the broken line in FIG. 6 (B). Panel (5) with long light source (3)
The rotation of the projection on the inner surface can be reduced, and the meandering of the stripe (2) can be corrected by appropriately selecting the radii R ₁ and R ₂ of the inner and outer surfaces.

In FIG. 5, (6) is a landing correction lens, (7) is a light distribution correction filter, and (8) is a shadow mask.

Although it is possible to correct the meandering of the stripe (2) by using the exposure apparatus equipped with the negative meniscus lens (4) as described above, even if the meandering of the stripe (2) is corrected, FIG. As shown in, when light is irradiated using the shadow mask (8) in which the slot-shaped through holes (10) are arranged through the bridge (11), the long elongated holes are elongated in the arrangement direction of the slot-shaped through holes (10). Even if the light source (3) is used, the pulse (5) inner surface has portions with different irradiation doses corresponding to the through hole (10) and the bridge (11), respectively, so that it is formed as shown in FIG. The striped stripes (2) are narrowed.

In order to correct this constriction, it is necessary to make the irradiation amount of the portion corresponding to the through hole (10) and the bridge (11) uniform. To this end, the length l of the long light source (3) can be calculated by the following equation. Should be satisfied.

Here, L ₀ is the distance from the long light source (3) to the inner surface of the panel (5), q is the distance from the shadow mask (8) to the inner surface of the panel (5), and P is the longitudinal direction of the slot-shaped through hole (10). It is the pitch along.

However, the value of L ₀ / q is not constant in the entire screen, and becomes larger in the peripheral portion in the direction along the longitudinal direction of the long light source (3) than in the central portion of the screen, and becomes smaller in the peripheral portion in the direction orthogonal to the longitudinal direction. Among these, by changing the shape of the long light source (3) light source cover in the direction orthogonal to the longitudinal direction of the light source (3), the constriction of the stripe (2) can be corrected according to the optimum light source length. . However, with respect to the direction along the longitudinal direction, there is no correction means, and there is a problem that a constriction occurs around the screen and the image quality of the color picture tube deteriorates.

[Object of the Invention]

The present invention has been made in view of the above-mentioned problems, and provides an exposure apparatus for forming a fluorescent screen of a color picture tube, which is capable of correcting not only stripe meandering but also constriction by improving a negative meniscus lens. It is intended to be provided.

[Outline of Invention]

According to the present invention, a trajectory of light emitted from an elongated long light source in the Y-axis direction is sequentially corrected by a negative meniscus lens and a landing correction lens, and a spherical shadow mask linearly arranged in the Y-axis direction via a bridge. In a fluorescent screen forming exposure device of a color picture tube, which is configured to irradiate a spherical panel inner surface through a slot-shaped through hole,
When the central axis of the negative meniscus lens is the Z axis and the axis orthogonal to the Z axis and the Y axis is the X axis, a YZ plane including the Y axis and the Z axis and a YZ parallel plane parallel to the YZ plane and the negative meniscus lens It is intended to improve the meandering and constriction of stripes formed on the inner surface of the panel by making the curvature of the line of intersection with the outer surface of the panel larger than the top of the line of intersection.

Example of Invention

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of an exposure apparatus. That is, in the exposure apparatus, the upper end surface (21) of the frame (20) is used as a mounting portion of the panel (5), and the panel (5) having the shadow mask (8) attached to the upper end surface (21) is positioned. It is supposed to be placed. Inside the frame (20), a light source (3), a negative meniscus lens (22), a landing correction lens (6), are sequentially provided toward the panel (5).
The light distribution correction filter (7) and the like are arranged by a support base (not shown). Among these configurations, the configurations and operations of the landing correction lens (6) and the light distribution correction filter (7) are known, and thus detailed description thereof will be omitted. Further, the light source (3) has a long and narrow linear shape, and its longitudinal direction is linearly arranged through the bridge of the shadow mask (8) attached to the panel (5) positioned on the upper end surface (21). The slot-shaped through holes are arranged so as to coincide with the arrangement direction.

2A and 2B show the shape of the negative meniscus lens (22) of the embodiment. That is, the negative meniscus lens (22) has the Z axis as the axis passing through the center, the Y axis as the longitudinal direction of the long light source (3), and the X axis as the axis orthogonal to the Y axis and the Z axis. YZ including the outer surface and Y-axis and Z-axis
The curvature of the line of intersection (24) with the plane is small near the center and large at the periphery. Further, the curvature of the line of intersection between the YZ plane parallel to the YZ plane and the outer surface of the negative meniscus lens (22) is also larger in the peripheral portion than in the vicinity of the top (23) of this line of intersection. This shape can be created, for example, by setting the shape of the line of intersection between the YZ plane and the YZ parallel plane and the outer surface of the negative meniscus lens (22) to be an ellipse having a short axis on the XZ plane including the X axis and the Z axis. it can. The outer surface of such a negative meniscus lens (22) is not rotationally symmetrical like the outer surface of the negative meniscus lens (4). By irradiating the inner surface of the panel (5) with light through the slot-shaped through holes using the negative meniscus lens (22), it is possible to form a stripe without meandering or constriction for the following reasons.

First, regarding the meandering of the stripes (2) formed on the inner surface of the panel (5), the curvature of the shadow mask (8) and the panel (5) is the same as in the exposure apparatus using the conventional negative meniscus lens (4). Correspondingly, the projection of the long light source (3) onto the inner surface of the panel (5) is rotated.
In this case, since the meandering of the stripe (2) is formed around the corner as described above, the shape of the negative meniscus lens (22) corresponding to this part may be optimized.

On the other hand, regarding the constriction of the stripe (2) formed on the inner surface of the panel (5), the negative meniscus lens (22)
The curvature of the line of intersection between the outer surface of the and the YZ plane and the YZ parallel plane is small near the top (23) of this line of intersection and is large in the area corresponding to the exposure on the long side peripheral part of the panel (5). There is. By the way, the negative meniscus lens (22) has a concave lens action as a whole to reduce the image, but the outer surface has a convex lens action to enlarge the image, and the inner surface has a concave lens action to reduce the image. Therefore, when the negative meniscus lens (22) of the embodiment is used, as shown in FIGS. 3 (A) and 3 (B), the convex lens action in the direction along the Y axis is weak near the top (23), and the concave lens action on the inner surface. Is strong, the reduction ratio of the image (25) of the long light source (3) becomes large. On the other hand, in the area corresponding to the peripheral portion on the long side of the panel (5), the convex lens action on the outer surface is strong, and the image (26) of the long light source (3) has a large enlargement ratio,
The reduction rate of the negative meniscus lens (22) is small. Therefore, the length of the long light source (3) apparently differs due to the negative meniscus lens (22) in the region near the top (23) and the peripheral portion on the long side of the panel (5), and the long side of the panel (5). The peripheral area is longer. That is, by balancing the curvature of the line of intersection between the outer surface of the negative meniscus lens (22) and the YZ plane or the YZ parallel plane in the area corresponding to the vicinity of the top (23) and the peripheral part of the long side of the panel (5). The narrowing of the stripe (2) can be corrected as the optimum light source length.

For example, the shape of the line of intersection between the negative meniscus lens (22) and the YZ plane and the YZ parallel plane has an outer surface and an inner surface each having a radius of 38.
From the circle of mm and 26 mm, the outer surface is Z ² / A ² + Y ² / B ² = 1 (however, A
= 5 and B = 28), the ratio of the apparent light source length in the central part to the peripheral part in the 21-inch color picture tube is 1: 0.8 from 1 in the case of changing to an ellipse with a short axis on the Z axis. : 0.92, Y
The stripe necking near the intersection of the Z plane and the inner surface of the panel was improved. Further, when the shape of the line of intersection between the outer surface of the negative meniscus lens and the YZ parallel plane is an ellipse having a minor axis on the XZ plane, the constriction of stripes is improved over the entire screen.

Regarding the shape of the inner surface of the negative meniscus lens, it is only necessary to optimally match the meandering and constriction of the stripes in accordance with the shape of the outer surface, and it is not necessary to use an approximate spherical surface as in the conventional case.

〔The invention's effect〕

As described above, according to the present invention, by partially changing the shape of the negative meniscus lens, it is possible to correct both the meandering and the constriction of the stripes formed on the inner surface of the panel, and the fluorescence of the color picture tube. An exposure device for surface formation can be provided.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an embodiment of an exposure apparatus for forming a fluorescent screen of a color picture tube of the present invention, FIG. 2 (A) is a plan view of the negative meniscus lens of FIG. 1, and FIG. 2 (B). Is a sectional view taken along the Y-axis of FIG. 2A, FIGS. 3A and 3B are explanatory views showing the action of the negative meniscus lens, and FIG. 4 shows the meandering of stripes formed on the inner surface of the panel. Explanatory drawing, FIG. 5 is a schematic explanatory view of an example of a conventional exposure apparatus for forming a fluorescent screen of a color picture tube, FIG. 6 (A) is a plan view of the negative meniscus lens of FIG. 5, and FIG. 6 (B). 6A is an X-axis sectional view of FIG. 6A, FIG. 7 is an explanatory view showing the relationship between the long light source, the shadow mask, and the inner surface of the panel, and FIG. 8 is an explanatory view showing the constriction of stripes formed on the inner surface of the panel. Is. 2 …… stripes, 3 …… light source 4,22 …… negative meniscus lens, 5 …… panel 8 …… shadow mask, 10 …… through hole 11 …… bridge

Claims (2)

[Claims] 1. A spherical shape linearly arrayed through a bridge in the Y-axis direction by sequentially correcting the trajectory of light emitted from a long light source elongated in the Y-axis direction by a negative meniscus lens and a landing correction lens. A color picture tube adapted to irradiate an inner surface of a spherical panel through a slot-shaped through hole of the shadow mask, and form an elongated linear stripe in the array direction of the slot-shaped through hole on the inner surface of the panel. In the exposure apparatus for forming a fluorescent screen, when the central axis of the negative meniscus lens is the Z axis and the axis orthogonal to the Z axis and the Y axis is the X axis, the YZ plane including the Y axis and the Z axis and the Exposure for forming a fluorescent screen of a color picture tube, characterized in that the curvature of the line of intersection between the YZ plane parallel to the YZ plane and the outer surface of the negative meniscus lens is made larger at the peripheral portion than at the top of this intersection line. Location. 2. The outer surface of the negative meniscus lens and the YZ plane and YZ.
The exposure for forming a fluorescent screen of a color picture tube according to claim 1, wherein the shape of the line of intersection with the parallel plane is an ellipse having a short axis on the XZ plane including the X axis and the Z axis. apparatus.