JPH0616376B2 - Color picture tube screen exposure method - Google Patents

Description

The present invention relates to a method for exposing a color picture tube picture screen.

The exposure method for forming the fluorescent surface which is the image screen of the color picture tube is a black matrix film (hereinafter referred to as B
The method in which the formation of the M film) and the formation of the fluorescent film (hereinafter referred to as the PH film) are performed under the same condition has no positional deviation from the BM film and the PH film, and its correction is also unnecessary. However, BM
The film thickness of the photoresist at the time of forming the film is very thin, for example, about 0.6 μm, whereas the film thickness of the phosphor slurry at the time of forming the PH film is, for example, about 30 μm, which is much thicker than the film thickness of the photoresist. Further, the photoresist and the phosphor slurry have different photosensitivity characteristics, and further, the BM film is smaller than the opening hole of the shadow mask, that is, in the case of the slot type opening hole, the width of the BM film is smaller than the width of the slot, and the circular opening hole The diameter of the BM film is smaller than the diameter of the circular shape, and the PH film is larger than the opening hole of the shadow mask because of the film thickness. In the case of the slot-shaped opening hole, the width of the PH film is larger than the width of the slot and the circular opening In the case of holes, since the PH film is formed larger than the circular diameter, forming both under the same conditions reduces the margin of BM film formation and reduces the adhesive strength of the PH film formation (illuminance x Time) is at a disadvantage.

The present invention has been made in view of the above background, and it is possible to improve the margin of BM film formation and the adhesive strength of PH film formation, respectively, and prevent the positional deviation between the BM film and the PH film. It is an object of the present invention to provide a method of exposing the same.

The present invention will be described below with reference to an embodiment shown in the drawings. As shown in FIG. 1, the fluorescent surface of the color picture tube is formed on the shadow mask 4 by an exposure device using a mercury lamp as a linear light source 3 on the photoresist or the phosphor slurry 2 applied to the inner surface of the panel 1. The slit pattern 5 of the formed opening is exposed to light and, as shown in FIG.
The film stripe 6 and the PH film stripe 7 are formed. At this time, the maximum exposure range Dmax and the minimum exposure range Dmin of the light spot 8 are as follows: the diameter of the light source 3 is A, the slit width of the slit pattern 5 is B, the distance from the light source 3 to the shadow mask 4 is P, and the shadow mask 4 is When the distance to the inner surface of the panel 1 is Q, it can be roughly geometrically expressed by the following equation.

Dmax = (B + A) × Q / P + B Dmin = (B−A) × Q / P + B This relationship is shown in FIG.

The width C of the BM film stripe 6 is formed smaller than the width of the electron beam, that is, smaller than the slit width B of the slit pattern 5 in order to improve the purity margin. This will be described with reference to FIG. 3. The exposure exposure is performed at the Dmin side of the light spot 9. That is, as the light source diameter A increases, Dmin decreases, which is advantageous for forming a small BM film stripe 6.

The PH film stripe 7 is formed by exposing a photoconductor slurry having a large film thickness of, for example, 30 μm by exposure, and thus a sufficient exposure amount is required. Explaining this with reference to FIG. 3, increasing the exposure amount results in exposure at Dmax. That is, the width E of the PH film stripe 7 is larger than the slit width B of the slit pattern 5, but the maximum width is set so as not to extend to the adjacent PH film stripe 7. For this, Dmax is as small as possible
The smaller the difference between min and Dmax, the more advantageous. In order to satisfy this, it is better that the light source diameter A is smaller.

Therefore, when the BM film stripe 6 is formed, exposure is performed with an exposure device having a light source diameter A larger than that when the PH film stripe 7 is formed, so that the margin of forming the BM film stripe 6 is improved and the PH film stripe 7 is formed. The adhesive strength is improved. Further, since there is a considerable difference between the thickness of the photoresist and the thickness of the phosphor slurry, the distance between the light source and the shadow mask is set to a value between when the BM film is formed and when the PH film is formed in consideration of the difference. By setting the different dimensions in, the positional deviation between the PH film and the BM film is prevented. That is, as shown in FIG. 4, when the photoresist film 2a is exposed from the light source 3 at the point a through the slit pattern 5 of the opening hole of the shadow mask 4, the point A is exposed, and the BM film centered at the point A is formed. It is formed. On the other hand, when the phosphor film 2b is exposed from the same point a as the exposure of the BM film, the phosphor film 2b is exposed centering on the point A ₁ due to the difference in film thickness, and a PH film centering on the point A ₁ is formed. Positional displacement occurs by the distance AB. Therefore, the light source 3 at the point b, which is closer to the shadow mask 4 than the point a, is exposed so as to expose the fluorescent film 2b at the point C whose center coincides with the point A.
From the above, it is possible to prevent the positional deviation between the BM film and the PH film. When the thickness of the phosphor slurry is T, the distance ΔP between the points a and b is ΔP = T × (P / Q) from the condition that the triangular diameter ALC is similar to the triangular NLM in FIG.
Is calculated as For example, the light source diameter A is 1.5 mmφ when the BM film stripe 6 is formed, 0.9 mmφ is used when the PH film stripe 7 is formed, and the distance P from the light source 3 to the shadow mask 4 is when the BM film stripe 6 is formed. When the exposure position deviation was corrected by making the value 0.3 mm larger than when the PH film stripe 7 was formed, good results were obtained. Here, the BM film stripe 6 due to the difference in light source diameter
The exposure position shift between the photo film stripe 7 and the PH film stripe 7 can be dealt with by changing the distance P as described above, but it can also be dealt with by changing the plate thickness of the correction lens and the glass plate (not shown). Further, the light source diameter may be the same for the BM film and the PH film for preventing the positional deviation.

By thus changing the distance between the light source and the shadow mask, the BM film stripe 6 and the PH film stripe 7 are formed.
Although the quality of formation can be improved, when forming a stripe fluorescent surface, as shown in FIG.
The bridge portion 9 in the longitudinal direction may be erased. In order to erase the bridge portion 9, if the pitch of the bridge portion 9 is F and the length of the linear light source 3 is 1, then l = (P + Q)
A linear light source 3 having a length of / Q · F is required.

However, if the length 1 of the linear light source 3 is exposed with the same length when the BM film stripe 6 is formed and when the PH film stripe 7 is formed, the effective surface of the PH film stripe 7 is longer than the BH film stripe 6. Since it is formed to be small in the direction, a non-luminous portion is generated at the end portion in the longitudinal direction, which becomes a defect of the fluorescent surface. This is because the light source length 1 at the time of exposure of the PH film stripe 7 is set to the light source length 1 at the time of exposure of the BM film stripe 6.
For example, the non-luminous portion could be removed by increasing the length by 3 to 4 mm. This can also be dealt with by changing the moving distance of the light source without changing the length 1 of the light source during both exposures.

Although the stripe type color picture tube has been described in the above embodiment, it can be applied to the formation of the fluorescent surface of the dot type color picture tube.

As is clear from the above description, according to the method of the present invention,
The margin of formation of the BM film is improved, the adhesive strength of the PH film is improved, and the displacement of the positions of both films can be prevented.

[Brief description of drawings]

FIG. 1 shows an embodiment of the method according to the present invention, FIG. 1 is an explanatory view of the principle of the exposure method, FIG. 2 is an explanatory plan view of a stripe type fluorescent surface, and FIG. 3 is an explanatory view showing exposure intensity. FIG. 4 is a principle explanatory diagram for explaining the position and dew point of the light source, and FIG. 5 is a principle explanatory diagram showing a linear light source length for erasing the bridge portion of the shadow mask. 1 ... Panel, 2 ... Photoresist or phosphor slurry, 3 ... Linear light source, 4 ... Shadow mask, 5 ...
Slit pattern, 6 ... BM film stripe, 7 ... P
H film stripe, 8 ... Spot.

Claims (1)

[Claims] 1. A color picture tube in which a photoresist and a phosphor slurry coated on the inner surface of a panel are exposed to light from a light source through an opening hole of a shadow mask to form a black matrix film and a phosphor film by an exposure device. In the method of exposing a video screen, when the fluorescent film is formed after the black matrix film is formed, the point on the light source side in the vertical direction from the exposed point when the black matrix film is formed is the point on the light source side by the film thickness of the phosphor slurry. An exposure method for a picture screen of a color picture tube, wherein the light source is moved to the panel side so as to be exposed to perform the exposure.