JPH04296426A - Exposure device and manufacture of color image receiving tube - Google Patents

Abstract

PURPOSE:To improve the purity by moving a shielding plate in a perpendicular direction to the alignment direction of an in-line electron gun, as well as by moving the position of an exposing light source in the alignment direction of the in-line electron gun in synchronism with the shielding plate. CONSTITUTION:Upon the exposure of a side dot, located at the position corresponding to a deflection center is a light source 1, which moves in the X-axis direction of a color image receiving tube in synchronism with the Y-axis directional movement of a shielding plate 14 having an opening longer in the X-axis direction, the light emitted from the light source 1 is passed through a correcting lens 2, for coinciding it with the final locus of a deflected electron beam, and the opening of a shadow mask 4 mounted on a panel 3 so as to expose a fluorescent surface 5 painted on the inner surface of the panel 3. The exposing device contains a mechanism for replacing the change of a slit position with the change dx of the light source 1 by means of a cam 20, the amount of the movement of the light source 1 is decided from an amount of landing required for correction, and is set by means of the shape of the cam 20. Thereby the purity can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and a method of manufacturing a color picture tube.

0002

2. Description of the Related Art Conventionally, an exposure apparatus used to form a fluorescent screen of a color picture tube has a light source 1 placed at a position corresponding to the center of deflection of the color picture tube, as shown in FIG. 2(A). The light emitted from the light source 1 is corrected by a correction lens 2 to match the final trajectory of the electron beam deflected by the deflection yoke of the color picture tube, and a photosensitive fluorescent film is applied via a shadow mask 4. The fluorescent screen 5 of the panel 3 is irradiated and developed to form phosphor dots.

For example, in the case of a phosphor dot on the right side corresponding to an electron gun that is not in the center of the in-line electron gun, FIG.
), a light source 1 is placed at a position corresponding to the deflection center of the color picture tube with a distance S corresponding to the spacing between the electron guns in the in-line electron gun arrangement direction, and the light emitted from this light source 1 is used to receive a color image. Correction lens 2 for matching the final trajectory of the electron beam deflected by the deflection yoke of the tube
The phosphor screen 5 of the panel 3 coated with the photosensitive phosphor film is irradiated through the shadow mask 4 and developed to form phosphor dots.

0004

[Problems to be Solved by the Invention] The correction lens used in the conventional method of manufacturing color picture tubes must be designed so that the landing error of the three colors is minimized. There are cases where correction is impossible.

This will be explained using FIGS. 3(A) and 3(B).

The arrow shown in FIG. 3(A) indicates the distance from the center 6 of the phosphor dot to the center 7 of the electron beam in FIG.
(landing error amount).

As shown in FIG. 3(A), the screen center 8 and
The landing errors for the three colors are 0 at the axis end 9, the corner 10, and the intermediate part 11, but the landing error is maximum at the Y-axis upper end 12, and both side beams are closer to the center dot. direction. Further, this tendency gradually decreases toward the screen diagonal axis corner 10, and reaches a minimum value of 0 at the corner 10.

[0008] Such a landing error is generally
Often when an in-line self-convergence type deflection yoke is used, the three electron beams are concentrated at the center of the screen.
Moreover, this occurs because the deflection yoke is provided with a complex magnetic field distortion to minimize image distortion.

Therefore, in order to minimize the landing error, the design of the correction lens was modified, and as a result, the phosphor dots moved in a direction and size similar to the arrows shown in FIG. Therefore, at the upper end 12 of the Y-axis, the landing error of the center beam was zero, but the center dot direction components remained in the side beams. The landing error decreased to the minimum in most areas of the screen, including the areas that did not require correction before the correction, but the landing error in the X-axis direction for the side beam at the upper end 12 of the Y-axis only could not be reduced. This is because since the lens surface is a continuous curved surface, the lens surface inclination in the X direction cannot be made to a predetermined inclination at each point.

As described above, it is impossible to correct the landing errors shown in FIGS. 3A, 3B and 4 using a continuous curved lens. On the other hand, it is possible to correct the discontinuous surface lenses that have been used in some cases, but it requires a large number of mold jigs and tools for lens processing, is expensive, and has problems caused by discontinuities. There are many limitations to using a discontinuous lens, such as the need for a mechanism to eliminate shadows on the fluorescent screen.

An object of the present invention is to provide an exposure apparatus and a method for manufacturing a color picture tube that improve purity by optimally forming phosphor dots on a panel surface by combining a continuous surface correction lens and movement of a light source. There is a particular thing.

0012

[Means for Solving the Problems] The exposure apparatus of the present invention includes a movable exposure source, a correction lens fixed above the exposure source, and an in-line lens disposed between the correction lens and the exposure source. Move in the direction perpendicular to the arrangement direction of the electron gun,
It has a light shielding plate that limits the exposure area in a direction perpendicular to the in-line electron gun array direction, and a mechanism that moves the position of the exposure source in the in-line electron gun array direction in synchronization with the light shielding plate.

In the method of manufacturing a color picture tube of the present invention, the light shielding plate of the exposure device is moved in a direction perpendicular to the arrangement direction of the inline electron guns, and the position of the exposure source is moved to the inline electron gun in synchronization with the light shielding plate. The method includes a step of moving the electron guns in the array direction and exposing phosphor dots corresponding to electron guns disposed on both outer sides of the in-line electron guns.

[0014]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

1(A) and 1(B) are cross-sectional views of an exposure apparatus used in an embodiment of the present invention, and FIG. 1(B) is a cross-sectional view of an exposure apparatus used in an embodiment of the present invention.
) is a cross-sectional view in the right angle direction.

As shown in FIGS. 1A and 1B, when exposing side dots, color image reception is performed in synchronization with the movement of the light-shielding plate 14, which has long openings in the X-axis direction, in the Y-axis direction. A light source 1 moving in the X-axis direction of the tube is placed at a position corresponding to the center of deflection, and a correction lens 2 and a panel 3 are attached to make the light emitted from the light source 1 coincide with the final trajectory of the deflected electron beam of the color picture tube. The fluorescent screen 5 coated on the inner surface of the panel 3 is exposed through the aperture of the shadow mask 4. The exposure apparatus has a mechanism that uses a cam 20 to replace a change in the slit position with a change dx in the light source 1, and the amount of movement of the light source 1 is determined from the landing amount that needs to be corrected and can be set by the shape of the cam 20. If light source 1 is moved by dx in the X-axis direction and the landing correction amount is ds, then ds=q・dx
/(L-q) holds true. Here, L indicates the distance between the inner surface of the panel 3 and the center of deflection, and q indicates the distance between the inner surface of the panel 3 and the shadow mask 4.

Therefore, for example, when calculating the dx that corrects the landing error q=15 μm when exposing the Y-axis upper end 12 shown in FIG. 4 of a 17-inch 90° screen, L=240.
Since mm, q=10 mm, dx=0.345 mm. In this way, by determining dx according to the amount of landing error and finely adjusting dx so that the error is minimized over the entire screen, the phosphor dots will be placed in the predetermined positions, and the phosphor dots manufactured in this way will be The color picture tube has an extremely good landing condition.

[0018]

As explained above, the present invention moves the light shielding plate of an exposure device in a direction perpendicular to the arrangement direction of the inline electron guns, and synchronizes the position of the exposure source with the inline electron gun array. By moving the in-line electron gun in the direction and exposing the phosphor dots corresponding to the electron guns placed on both outer sides of the in-line electron gun, landings that could not be corrected with conventional continuous curve correction lenses can be easily corrected.
It has the effect of improving purity.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an example of a conventional exposure apparatus.

FIG. 3 is a plan view illustrating an example of landing error of a conventional color picture tube.

FIG. 4 is a plan view showing another example of landing error of a conventional color picture tube.

[Explanation of symbols]

1 Light source 2 Correction lens 3 Panel 4 Shadow mask 5. Fluorescent screen 6 Center of phosphor dot 7 Center of electron beam 8 Center of screen 9 X-axis end 10 Corner part 11, 13 Middle part 12 Y-axis upper end 14　　　　Light shielding plate 20 Cam

Claims (2)

[Claims] 1. A movable exposure source, a correction lens fixed above the exposure source, and an in-line electron gun that is disposed between the correction lens and the exposure source and moves in a direction perpendicular to the arrangement direction. and a light shielding plate that limits the exposure area in a direction perpendicular to the inline electron gun array direction, and a mechanism for moving the position of the exposure source in the inline electron gun array direction in synchronization with the light shielding plate. An exposure device characterized by: 2. Moving the light shielding plate of the exposure device in a direction perpendicular to the arrangement direction of the in-line electron guns, and
The method further includes the step of moving the position of the exposure source in the direction of arrangement of the in-line electron guns in synchronization with the light shielding plate, and exposing phosphor dots corresponding to electron guns arranged on both outer sides of the in-line electron guns. Characteristic method for manufacturing color picture tubes.