JPS6024531B2 - Exposure correction filter manufacturing method and its manufacturing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a correction filter for adjusting the exposure amount in an exposure device used for forming a light surface of a color picture tube.

In the process of forming the crab light surface of a color picture tube, the crab photosensitive layer coated on the inner surface of the face panel is exposed to ultraviolet light through an attached shadow mask, and then subjected to development and other processing steps. By repeating this process, the crab light surface is made into dots or stripes. The exposure equipment used in the above process usually has a correction lens between the light source and the face panel to approximate the optical path to the electron beam trajectory, and a correction filter to adjust the exposure light amount over the entire surface. It has been inserted.

Fig. 1 shows a schematic cross-sectional view of the exposure state.
1 is a face panel, 2 is a crab photosensitive layer coated on the inner surface of the face panel, 3 is a shadow mask attached, and the exposure device is a point light source 4, a correction lens 5, and a correction filter 6. It is evening. Generally speaking, regarding the adjustment of the light amount of the correction filter 6, when the point light source 4 is used as the light source, the amount of light at the center of the face panel 1 will be too large unless it is corrected, and the light will be formed on the inner surface of the face panel. The diameter of a large number of crab photon dots or the width of a crab photon stripe is
The center part of the face panel and the circumferential part are not aligned.

For this reason, it is generally necessary to adjust the amount of light by using a correction filter 6 with low transmittance at the center. The correction filter 6 is made by depositing a metal thin film on a transparent substrate such as glass, and is manufactured by the manufacturing method described below.

That is, metals such as Inconel, chromel, and platinum are evaporated from a circular evaporation source in a vacuum, and a thin film is formed on the surface of a transparent substrate such as glass through a evaporation mask with star-shaped holes. There it is. At this time, the transmittance of the correction filter 6
Some manufacturing equipment was equipped with a mechanism that rotated the transparent substrate so that it was evenly raised in each direction from the center of the substrate. The transmittance distribution of the correction filter 6 obtained by the conventional manufacturing apparatus is such that the transmittance curve 7 in FIG. 2 is obtained in each direction passing through the center 0 of the correction filter 6.

As shown in Figure 3, the edge of the face panel 1 is the X axis 8,
Assuming that the short side direction is the Y axis 9 and the diagonal direction is the diagonal axis 10,
The dots on the crab light surface formed using the correction filter 6 are as shown in FIG. 11 is an X-axis dot curve (broken line), 12 is a Y-axis dot curve (solid line), 13 is a diagonal axis dot curve (single-dot head line), and 14 is the beam diameter.

At the same distance from the face panel center 0, the dot diameter in the X-axis direction generally becomes large, and the difference 15 from the beam diameter becomes small. That is, since the landing margin of the beam becomes small, color shift is particularly likely to occur around the face panel in the x-axis direction, causing deterioration in image quality. In order to eliminate the above-mentioned drawbacks, it is possible to use a correction filter with different transmittance curves in the Attempts were made to obtain a correction filter by making the process extremely complicated, but in reality the process involved repeated trial and error, resulting in large losses in the manufacturing process.

The present invention provides a manufacturing method and an apparatus for manufacturing the same, which can highly accurately obtain a correction filter having a different transmittance in each direction, such as the x-axis direction, using an evaporation source and a deposition mask that have extremely simple shapes. This embodiment will be described in detail with reference to FIG. 5 and the following drawings.

As shown in a cross-sectional view in FIG. 5, 16 is a metal bell jar, which is airtightly placed on a base 17, and its interior is evacuated to create a vacuum.

Reference numeral 18 denotes an evaporation source which is linear and is most simply formed by winding a thin metal wire such as Inconel or the like to be evaporated around a linear tungsten wire heater.

Reference numerals 19 and 20 are vapor deposition masks, and 21 is a transparent substrate such as glass that is an object to be vapor deposited.

FIG. 6 shows a perspective view of the main parts. Face panel 1 in Figure 3
○1X'Y on the transparent substrate 21 corresponding to the ○-XY coordinates of
The coordinates are determined, and the completed correction filter is used in a direction in which its X' axis coincides with the X axis of the face panel.
The vapor deposition masks 19 and 20 each have a seal opening 2 having a large opening diameter in the X'-axis direction and a small opening diameter in the Y'-axis direction.
Although the shapes of 2 and 23 are arbitrary, oval shapes are used here. Comparing the elliptical openings 22 and 23, their longest axes have approximately the same length, and their short axes are smaller at the entrance 22 of the vapor deposition mask 19, which is closer to the evaporation source. On the other hand, the linear evaporation source 18 is arranged in alignment with the Y'-axis direction. In order to show the vapor deposition state, FIG. 7A is a sectional view taken along a plane including the X' axis in FIG. 6, and FIG. 7B is a sectional view taken along a plane including the Y' axis.

When viewed from the transparent substrate 21, the Sekiguchi fleas at the openings 22 and 23 of the vapor deposition masks 19 and 20 are large in the X'-axis direction, and the evaporation source 18 is also close to a point evaporation source, so the transmittance in the X'-axis direction is is like a curve 24 shown by a broken line in FIG. 8, and exhibits a characteristic in which the transmittance gradually increases toward the circumferential portion. On the other hand, in the Y'-axis direction, the evaporation source 18 is linear, the closed diameter of the opening 23 of the deposition mask 20 is small, and the opening diameter of the opening 22 of the vapor deposition mask 19 is even smaller, so that the completed correction As shown by curve 25 (solid line), the transmittance of the filter is low at the center and high at the periphery, showing a characteristic that it gradually increases. And in the diagonal axis direction, the dashed line curve 26
The value is an intermediate value between the above two curves 24 and 25, as shown in FIG.

If the crab photosensitive layer 2 of the face panel 1 is exposed using the correction filter obtained as described above, in the case of the conventional correction filter 6 having the same transmittance distribution curve 7 on each axis, The characteristics that resulted in the dot distribution as shown in Figure 4 are compensated for by different transmittance distributions on each axis as shown in Figure 8, and it is possible to obtain almost the same dot diameter distribution at the same distance from the center of the face panel. is possible.

The transmittance curve for each axial direction is determined not only by the shape and size of the closed parts 22 and 23 of the evaporation masks 19 and 20 but also by the length of the linear evaporation source and from this evaporation source 18 to the evaporation masks 19 and 20. , can be changed depending on the distance to the transparent substrate 21, providing a high degree of freedom in design.

Particularly in the Y-axis direction shown in FIG. 7A, the thickness of the evaporated film on the transparent substrate 21 changes gradually due to the opening 22 of the evaporation mask 9 closer to the evaporation source 18, so that the desired transmittance curve can be adjusted. It can be obtained easily and with high precision. Furthermore, the ninth
As shown in the figure, the shapes of the entrances 22a and 23a of the vapor deposition masks 19a and 20a are changed, and the point 27 when viewed from above is
This point 2 can be solved by configuring the structure so that the overlapping method changes at the border.
Since the amount of evaporation is more greatly controlled by the evaporation mask 19a on the Y-axis side from 7 and by the evaporation mask 20a on the X'-axis side,
In particular, the transmittance distribution between the X' axis and the Y' axis, such as the diagonal axis direction, can be controlled with high precision.

Further, the shape of the closing portions 22, 23, 22a, 23a, etc. is not limited to the approximately oval shape as in the above embodiment;
A combination with a rectangle, a diamond, etc. may also be used. That is, it becomes easier to design and manufacture a vapor deposition mask, and the cost of this manufacturing apparatus can be significantly reduced. In the above, two vapor deposition masks were used, but by increasing the number of masks, the transmittance curve obtained will be extremely accurate, and it will be possible to obtain a high-quality image with very little color shift in each direction. is possible.

As described above, the present invention inserts a plurality of closed evaporation masks between a linear evaporation source and a transparent substrate to serve as a correction filter, and each of these evaporation masks is connected to the linear evaporation source. The aperture diameter in the line direction of the source is smaller than the aperture diameter in the direction perpendicular to the line direction, and the closer the evaporation mask is to the evaporation source, the smaller the aperture diameter in the line direction is at least at the center. By forming a vapor-deposited thin film on the transparent substrate, an excellent correction filter for exposure can be easily produced with high precision, using a simple-shaped evaporation source and a vapor deposition mask, with different transmittances in each direction. The present invention provides a manufacturing method and an apparatus for manufacturing the same.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the exposure state of the face panel;
The figure is a transmittance distribution curve diagram of a conventional correction filter, Figure 3 is a plan view showing the coordinate axes of the face panel, Figure 4 is a dot flea distribution diagram of a crab light surface by a conventional correction filter, and Figure 5 is A sectional view showing an embodiment of the exposure correction filter manufacturing apparatus of the present invention, FIG. 6 is a perspective view of the same essential part, FIG. 7 A and B are a sectional view of the same essential part showing the vapor deposition state, FIG. is a transmittance distribution curve diagram,
FIG. 9 is a plan view of main parts showing another embodiment of the present invention. 18... Evaporation source, 19, 19a, 20, 20a
... Vapor deposition mask, 21 ... Transparent substrate,
22, 22a, 23, 23a...Closed part. 1st
Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 9 Figure 5 Figure 8

Claims (1)

[Claims] 1. A plurality of evaporation masks having openings are inserted between a linear evaporation source and a transparent substrate to serve as a correction filter,
Each of these vapor deposition masks has an aperture diameter in the linear direction of the linear evaporation source that is smaller than an aperture diameter in a direction perpendicular to the linear direction, and the closer the vapor deposition mask is to the evaporation source, the more the evaporation mask is located at least in the central portion in the linear direction. 1. A method of manufacturing an exposure correction filter, comprising: arranging the transparent substrate with a small opening diameter, and forming a vapor-deposited thin film on the transparent substrate. 2. Consisting of an evaporation source, a transparent substrate to serve as a correction filter, and a plurality of evaporation masks having openings provided between the evaporation source and the transparent substrate, the evaporation source is a linear evaporation source, while each The evaporation mask is fixed in a direction in which the aperture diameter in the linear direction of the linear evaporation source is smaller than the aperture diameter in the direction perpendicular to the linear direction, and the aperture diameter in the linear direction is smaller at least in the central part. A manufacturing device for an exposure correction filter, characterized in that a mask is placed on the side of an evaporation source.